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diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
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+*   When calling `update_columns` on a record that is not persisted, the error
+    message now reflects whether that object is a new record or has been
+    destroyed.
+
+    *Lachlan Sylvester*
+
+*   Define `id_was` to get the previous value of the primary key.
+
+    Currently when we call id_was and we have a custom primary key name
+    Active Record will return the current value of the primary key. This
+    make impossible to correctly do an update operation if you change the
+    id.
+
+    Fixes #16413.
+
+    *Rafael Mendonça França*
+
+*   Deprecate `DatabaseTasks.load_schema` to act on the current connection.
+    Use `.load_schema_current` instead. In the future `load_schema` will
+    require the `configuration` to act on as an argument.
+
+    *Yves Senn*
+
+*   Fixed automatic maintaining test schema to properly handle sql structure
+    schema format.
+
+    Fixes #15394.
+
+    *Wojciech Wnętrzak*
+
+*   Fix type casting to Decimal from Float with large precision.
+
+    *Tomohiro Hashidate*
+
+*   Deprecate `Reflection#source_macro`
+
+    `Reflection#source_macro` is no longer needed in Active Record
+    source so it has been deprecated. Code that used `source_macro`
+    was removed in #16353.
+
+    *Eileen M. Uchtitelle*, *Aaron Patterson*
+
+*   No verbose backtrace by db:drop when database does not exist.
+
+    Fixes #16295.
+
+    *Kenn Ejima*
+
+*   Add support for Postgresql JSONB.
+
+    Example:
+
+        create_table :posts do |t|
+          t.jsonb :meta_data
+        end
+
+    *Philippe Creux*, *Chris Teague*
+
+*   `db:purge` with MySQL respects `Rails.env`.
+
+    *Yves Senn*
+
+*   `change_column_default :table, :column, nil` with PostgreSQL will issue a
+    `DROP DEFAULT` instead of a `DEFAULT NULL` query.
+
+    Fixes #16261.
+
+    *Matthew Draper*, *Yves Senn*
+
+*   Allow to specify a type for the foreign key column in `references`
+    and `add_reference`.
+
+    Example:
+
+        change_table :vehicle do |t|
+          t.references :station, type: :uuid
+        end
+
+    *Andrey Novikov*, *Łukasz Sarnacki*
+
+*   `create_join_table` removes a common prefix when generating the join table.
+    This matches the existing behavior of HABTM associations.
+
+    Fixes #13683.
+
+    *Stefan Kanev*
+
+*   Dont swallow errors on compute_type when having a bad alias_method on
+    a class.
+
+    *arthurnn*
+
+*   PostgreSQL invalid `uuid` are convert to nil.
+
+    *Abdelkader Boudih*
+
+*   Restore 4.0 behavior for using serialize attributes with `JSON` as coder.
+
+    With 4.1.x, `serialize` started returning a string when `JSON` was passed as
+    the second attribute. It will now return a hash as per previous versions.
+
+    Example:
+
+        class Post < ActiveRecord::Base
+          serialize :comment, JSON
+        end
+
+        class Comment
+          include ActiveModel::Model
+          attr_accessor :category, :text
+        end
+
+        post = Post.create!
+        post.comment = Comment.new(category: "Animals", text: "This is a comment about squirrels.")
+        post.save!
+
+        # 4.0
+        post.comment # => {"category"=>"Animals", "text"=>"This is a comment about squirrels."}
+
+        # 4.1 before
+        post.comment # => "#<Comment:0x007f80ab48ff98>"
+
+        # 4.1 after
+        post.comment # => {"category"=>"Animals", "text"=>"This is a comment about squirrels."}
+
+    When using `JSON` as the coder in `serialize`, Active Record will use the
+    new `ActiveRecord::Coders::JSON` coder which delegates its `dump/load` to
+    `ActiveSupport::JSON.encode/decode`. This ensures special objects are dumped
+    correctly using the `#as_json` hook.
+
+    To keep the previous behaviour, supply a custom coder instead
+    ([example](https://gist.github.com/jenncoop/8c4142bbe59da77daa63)).
+
+    Fixes #15594.
+
+    *Jenn Cooper*
+
+*   Do not use `RENAME INDEX` syntax for MariaDB 10.0.
+
+    Fixes #15931.
+
+    *Jeff Browning*
+
+*   Calling `#empty?` on a `has_many` association would use the value from the
+    counter cache if one exists.
+
+    *David Verhasselt*
+
+*   Fix the schema dump generated for tables without constraints and with
+    primary key with default value of custom PostgreSQL function result.
+
+    Fixes #16111.
+
+    *Andrey Novikov*
+
+*   Fix the SQL generated when a `delete_all` is run on an association to not
+    produce an `IN` statements.
+
+    Before:
+
+      UPDATE "categorizations" SET "category_id" = NULL WHERE
+      "categorizations"."category_id" = 1 AND "categorizations"."id" IN (1, 2)
+
+    After:
+
+      UPDATE "categorizations" SET "category_id" = NULL WHERE
+      "categorizations"."category_id" = 1
+
+    *Eileen M. Uchitelle, Aaron Patterson*
+
+*   Avoid type casting boolean and ActiveSupport::Duration values to numeric
+    values for string columns. Otherwise, in some database, the string column
+    values will be coerced to a numeric allowing false or 0.seconds match any
+    string starting with a non-digit.
+
+    Example:
+
+        App.where(apikey: false) # => SELECT * FROM users WHERE apikey = '0'
+
+    *Dylan Thacker-Smith*
+
+*   Add a `:required` option to singular associations, providing a nicer
+    API for presence validations on associations.
+
+    *Sean Griffin*
+
+*   Fixed error in `reset_counters` when associations have `select` scope.
+    (Call to `count` generates invalid SQL.)
+
+    *Cade Truitt*
+
+*   After a successful `reload`, `new_record?` is always false.
+
+    Fixes #12101.
+
+    *Matthew Draper*
+
+*   PostgreSQL renaming table doesn't attempt to rename non existent sequences.
+
+    *Abdelkader Boudih*
+
+*   Move 'dependent: :destroy' handling for 'belongs_to'
+    from 'before_destroy' to 'after_destroy' callback chain
+
+    Fixes #12380.
+
+    *Ivan Antropov*
+
+*   Detect in-place modifications on String attributes.
+
+    Before this change user have to mark the attribute as changed to it be persisted
+    in the database. Now it is not required anymore.
+
+    Before:
+
+        user = User.first
+        user.name << ' Griffin'
+        user.name_will_change!
+        user.save
+        user.reload.name # => "Sean Griffin"
+
+    After:
+
+        user = User.first
+        user.name << ' Griffin'
+        user.save
+        user.reload.name # => "Sean Griffin"
+
+    *Sean Griffin*
+
+*   Add `ActiveRecord::Base#validate!` that raises `RecordInvalid` if the record
+    is invalid.
+
+    *Bogdan Gusiev*, *Marc Schütz*
+
+*   Support for adding and removing foreign keys. Foreign keys are now
+    a part of `schema.rb`. This is supported by Mysql2Adapter, MysqlAdapter
+    and PostgreSQLAdapter.
+
+    Many thanks to *Matthew Higgins* for laying the foundation with his work on
+    [foreigner](https://github.com/matthuhiggins/foreigner).
+
+    Example:
+
+        # within your migrations:
+        add_foreign_key :articles, :authors
+        remove_foreign_key :articles, :authors
+
+    *Yves Senn*
+
+*   Fix subtle bugs regarding attribute assignment on models with no primary
+    key. `'id'` will no longer be part of the attributes hash.
+
+    *Sean Griffin*
+
+*   Deprecate automatic counter caches on `has_many :through`. The behavior was
+    broken and inconsistent.
+
+    *Sean Griffin*
+
+*   `preload` preserves readonly flag for associations.
+
+    See #15853.
+
+    *Yves Senn*
+
+*   Assume numeric types have changed if they were assigned to a value that
+    would fail numericality validation, regardless of the old value. Previously
+    this would only occur if the old value was 0.
+
+    Example:
+
+        model = Model.create!(number: 5)
+        model.number = '5wibble'
+        model.number_changed? # => true
+
+    Fixes #14731.
+
+    *Sean Griffin*
+
+*   `reload` no longer merges with the existing attributes.
+    The attribute hash is fully replaced. The record is put into the same state
+    as it would be with `Model.find(model.id)`.
+
+    *Sean Griffin*
+
+*   The object returned from `select_all` must respond to `column_types`.
+    If this is not the case a `NoMethodError` is raised.
+
+    *Sean Griffin*
+
+*   `has_many :through` associations will no longer save the through record
+    twice when added in an `after_create` callback defined before the
+    associations.
+
+    Fixes #3798.
+
+    *Sean Griffin*
+
+*   Detect in-place modifications of PG array types
+
+    *Sean Griffin*
+
+*   Add `bin/rake db:purge` task to empty the current database.
+
+    *Yves Senn*
+
+*   Deprecate `serialized_attributes` without replacement.
+
+    *Sean Griffin*
+
+*   Correctly extract IPv6 addresses from `DATABASE_URI`: the square brackets
+    are part of the URI structure, not the actual host.
+
+    Fixes #15705.
+
+    *Andy Bakun*, *Aaron Stone*
+
+*   Ensure both parent IDs are set on join records when both sides of a
+    through association are new.
+
+    *Sean Griffin*
+
+*   `ActiveRecord::Dirty` now detects in-place changes to mutable values.
+    Serialized attributes on ActiveRecord models will no longer save when
+    unchanged.
+
+    Fixes #8328.
+
+    *Sean Griffin*
+
+*   Pluck now works when selecting columns from different tables with the same
+    name.
+
+    Fixes #15649.
+
+    *Sean Griffin*
+
+*   Remove `cache_attributes` and friends. All attributes are cached.
+
+    *Sean Griffin*
+
+*   Remove deprecated method `ActiveRecord::Base.quoted_locking_column`.
+
+    *Akshay Vishnoi*
+
+*   `ActiveRecord::FinderMethods.find` with block can handle proc parameter as
+    `Enumerable#find` does.
+
+    Fixes #15382.
+
+    *James Yang*
+
+*   Make timezone aware attributes work with PostgreSQL array columns.
+
+    Fixes #13402.
+
+    *Kuldeep Aggarwal*, *Sean Griffin*
+
+*   `ActiveRecord::SchemaMigration` has no primary key regardless of the
+    `primary_key_prefix_type` configuration.
+
+    Fixes #15051.
+
+    *JoseLuis Torres*, *Yves Senn*
+
+*   `rake db:migrate:status` works with legacy migration numbers like `00018_xyz.rb`.
+
+    Fixes #15538.
+
+    *Yves Senn*
+
+*   Baseclass becomes! subclass.
+
+    Before this change, a record which changed its STI type, could not be
+    updated.
+
+    Fixes #14785.
+
+    *Matthew Draper*, *Earl St Sauver*, *Edo Balvers*
+
+*   Remove deprecated `ActiveRecord::Migrator.proper_table_name`. Use the
+    `proper_table_name` instance method on `ActiveRecord::Migration` instead.
+
+    *Akshay Vishnoi*
+
+*   Fix regression on eager loading association based on SQL query rather than
+    existing column.
+
+    Fixes #15480.
+
+    *Lauro Caetano*, *Carlos Antonio da Silva*
+
+*   Deprecate returning `nil` from `column_for_attribute` when no column exists.
+    It will return a null object in Rails 5.0
+
+    *Sean Griffin*
+
+*   Implemented ActiveRecord::Base#pretty_print to work with PP.
+
+    *Ethan*
+
+*   Preserve type when dumping PostgreSQL point, bit, bit varying and money
+    columns.
+
+    *Yves Senn*
+
+*   New records remain new after YAML serialization.
+
+    *Sean Griffin*
+
+*   PostgreSQL support default values for enum types. Fixes #7814.
+
+    *Yves Senn*
+
+*   PostgreSQL `default_sequence_name` respects schema. Fixes #7516.
+
+    *Yves Senn*
+
+*   Fixed `columns_for_distinct` of postgresql adapter to work correctly
+    with orders without sort direction modifiers.
+
+    *Nikolay Kondratyev*
+
+*   PostgreSQL `reset_pk_sequence!` respects schemas. Fixes #14719.
+
+    *Yves Senn*
+
+*   Keep PostgreSQL `hstore` and `json` attributes as `Hash` in `@attributes`.
+    Fixes duplication in combination with `store_accessor`.
+
+    Fixes #15369.
+
+    *Yves Senn*
+
+*   `rake railties:install:migrations` respects the order of railties.
+
+    *Arun Agrawal*
+
+*   Fix redefine a has_and_belongs_to_many inside inherited class
+    Fixing regression case, where redefining the same has_an_belongs_to_many
+    definition into a subclass would raise.
+
+    Fixes #14983.
+
+    *arthurnn*
+
+*   Fix has_and_belongs_to_many public reflection.
+    When defining a has_and_belongs_to_many, internally we convert that to two has_many.
+    But as `reflections` is a public API, people expect to see the right macro.
+
+    Fixes #14682.
+
+    *arthurnn*
+
+*   Fixed serialization for records with an attribute named `format`.
+
+    Fixes #15188.
+
+    *Godfrey Chan*
+
+*   When a `group` is set, `sum`, `size`, `average`, `minimum` and `maximum`
+    on a NullRelation should return a Hash.
+
+    *Kuldeep Aggarwal*
+
+*   Fixed serialized fields returning serialized data after being updated with
+    `update_column`.
+
+    *Simon Hørup Eskildsen*
+
+*   Fixed polymorphic eager loading when using a String as foreign key.
+
+    Fixes #14734.
+
+    *Lauro Caetano*
+
+*   Change belongs_to touch to be consistent with timestamp updates
+
+    If a model is set up with a belongs_to: touch relationship the parent
+    record will only be touched if the record was modified. This makes it
+    consistent with timestamp updating on the record itself.
+
+    *Brock Trappitt*
+
+*   Fixed the inferred table name of a has_and_belongs_to_many auxiliar
+    table inside a schema.
+
+    Fixes #14824.
+
+    *Eric Chahin*
+
+*   Remove unused `:timestamp` type. Transparently alias it to `:datetime`
+    in all cases. Fixes inconsistencies when column types are sent outside of
+    `ActiveRecord`, such as for XML Serialization.
+
+    *Sean Griffin*
+
+*   Fix bug that added `table_name_prefix` and `table_name_suffix` to
+    extension names in PostgreSQL when migrating.
+
+    *Joao Carlos*
+
+*   The `:index` option in migrations, which previously was only available for
+    `references`, now works with any column types.
+
+    *Marc Schütz*
+
+*   Add support for counter name to be passed as parameter on `CounterCache::ClassMethods#reset_counters`.
+
+    *jnormore*
+
+*   Restrict deletion of record when using `delete_all` with `uniq`, `group`, `having`
+    or `offset`.
+
+    In these cases the generated query ignored them and that caused unintended
+    records to be deleted.
+
+    Fixes #11985.
+
+    *Leandro Facchinetti*
+
+*   Floats with limit >= 25 that get turned into doubles in MySQL no longer have
+    their limit dropped from the schema.
+
+    Fixes #14135.
+
+    *Aaron Nelson*
+
+*   Fix how to calculate associated class name when using namespaced has_and_belongs_to_many
+    association.
+
+    Fixes #14709.
+
+    *Kassio Borges*
+
+*   `ActiveRecord::Relation::Merger#filter_binds` now compares equivalent symbols and
+    strings in column names as equal.
+
+    This fixes a rare case in which more bind values are passed than there are
+    placeholders for them in the generated SQL statement, which can make PostgreSQL
+    throw a `StatementInvalid` exception.
+
+    *Nat Budin*
+
+*   Fix `stored_attributes` to correctly merge the details of stored
+    attributes defined in parent classes.
+
+    Fixes #14672.
+
+    *Brad Bennett*, *Jessica Yao*, *Lakshmi Parthasarathy*
+
+*   `change_column_default` allows `[]` as argument to `change_column_default`.
+
+    Fixes #11586.
+
+    *Yves Senn*
+
+*   Handle `name` and `"char"` column types in the PostgreSQL adapter.
+
+    `name` and `"char"` are special character types used internally by
+    PostgreSQL and are used by internal system catalogs. These field types
+    can sometimes show up in structure-sniffing queries that feature internal system
+    structures or with certain PostgreSQL extensions.
+
+    *J Smith*, *Yves Senn*
+
+*   Fix `PostgreSQLAdapter::OID::Float#type_cast` to convert Infinity and
+    NaN PostgreSQL values into a native Ruby `Float::INFINITY` and `Float::NAN`
+
+    Before:
+
+        Point.create(value: 1.0/0)
+        Point.last.value # => 0.0
+
+    After:
+
+        Point.create(value: 1.0/0)
+        Point.last.value # => Infinity
+
+    *Innokenty Mikhailov*
+
+*   Allow the PostgreSQL adapter to handle bigserial primary key types again.
+
+    Fixes #10410.
+
+    *Patrick Robertson*
+
+*   Deprecate joining, eager loading and preloading of instance dependent
+    associations without replacement. These operations happen before instances
+    are created. The current behavior is unexpected and can result in broken
+    behavior.
+
+    Fixes #15024.
+
+    *Yves Senn*
+
+*   Fixed has_and_belongs_to_many's CollectionAssociation size calculation.
+
+    has_and_belongs_to_many should fall back to using the normal CollectionAssociation's
+    size calculation if the collection is not cached or loaded.
+
+    Fixes #14913, #14914.
+
+    *Fred Wu*
+
+*   Return a non zero status when running `rake db:migrate:status` and migration table does
+    not exist.
+
+    *Paul B.*
+
+*   Add support for module-level `table_name_suffix` in models.
+
+    This makes `table_name_suffix` work the same way as `table_name_prefix` when
+    using namespaced models.
+
+    *Jenner LaFave*
+
+*   Revert the behaviour of `ActiveRecord::Relation#join` changed through 4.0 => 4.1 to 4.0.
+
+    In 4.1.0 `Relation#join` is delegated to `Arel#SelectManager`.
+    In 4.0 series it is delegated to `Array#join`.
+
+    *Bogdan Gusiev*
+
+*   Log nil binary column values correctly.
+
+    When an object with a binary column is updated with a nil value
+    in that column, the SQL logger would throw an exception when trying
+    to log that nil value. This only occurs when updating a record
+    that already has a non-nil value in that column since an initial nil
+    value isn't included in the SQL anyway (at least, when dirty checking
+    is enabled.) The column's new value will now be logged as `<NULL binary data>`
+    to parallel the existing `<N bytes of binary data>` for non-nil values.
+
+    *James Coleman*
+
+*   Rails will now pass a custom validation context through to autosave associations
+    in order to validate child associations with the same context.
+
+    Fixes #13854.
+
+    *Eric Chahin*, *Aaron Nelson*, *Kevin Casey*
+
+*   Stringify all variables keys of MySQL connection configuration.
+
+    When `sql_mode` variable for MySQL adapters set in configuration as `String`
+    was ignored and overwritten by strict mode option.
+
+    Fixes #14895.
+
+    *Paul Nikitochkin*
+
+*   Ensure SQLite3 statements are closed on errors.
+
+    Fixes #13631.
+
+    *Timur Alperovich*
+
+*   Give ActiveRecord::PredicateBuilder private methods the privacy they deserve.
+
+    *Hector Satre*
+
+*   When using a custom `join_table` name on a `habtm`, rails was not saving it
+    on Reflections. This causes a problem when rails loads fixtures, because it
+    uses the reflections to set database with fixtures.
+
+    Fixes #14845.
+
+    *Kassio Borges*
+
+*   Reset the cache when modifying a Relation with cached Arel.
+    Additionally display a warning message to make the user aware.
+
+    *Yves Senn*
+
+*   PostgreSQL should internally use `:datetime` consistently for TimeStamp. Assures
+    different spellings of timestamps are treated the same.
+
+    Example:
+
+        mytimestamp.simplified_type('timestamp without time zone')
+        # => :datetime
+        mytimestamp.simplified_type('timestamp(6) without time zone')
+        # => also :datetime (previously would be :timestamp)
+
+    See #14513.
+
+    *Jefferson Lai*
+
+*   `ActiveRecord::Base.no_touching` no longer triggers callbacks or start empty transactions.
+
+    Fixes #14841.
+
+    *Lucas Mazza*
+
+*   Fix name collision with `Array#select!` with `Relation#select!`.
+
+    Fixes #14752.
+
+    *Earl St Sauver*
+
+*   Fixed unexpected behavior for `has_many :through` associations going through a scoped `has_many`.
+
+    If a `has_many` association is adjusted using a scope, and another `has_many :through`
+    uses this association, then the scope adjustment is unexpectedly neglected.
+
+    Fixes #14537.
+
+    *Jan Habermann*
+
+*   `@destroyed` should always be set to `false` when an object is duped.
+
+    *Kuldeep Aggarwal*
+
+*   Fixed has_many association to make it support irregular inflections.
+
+    Fixes #8928.
+
+    *arthurnn*, *Javier Goizueta*
+
+*   Fixed a problem where count used with a grouping was not returning a Hash.
+
+    Fixes #14721.
+
+    *Eric Chahin*
+
+*   `sanitize_sql_like` helper method to escape a string for safe use in an SQL
+    LIKE statement.
+
+    Example:
+
+        class Article
+          def self.search(term)
+            where("title LIKE ?", sanitize_sql_like(term))
+          end
+        end
+
+        Article.search("20% _reduction_")
+        # => Query looks like "... title LIKE '20\% \_reduction\_' ..."
+
+    *Rob Gilson*, *Yves Senn*
+
+*   Do not quote uuid default value on `change_column`.
+
+    Fixes #14604.
+
+    *Eric Chahin*
+
+*   The comparison between `Relation` and `CollectionProxy` should be consistent.
+
+    Example:
+
+        author.posts == Post.where(author_id: author.id)
+        # => true
+        Post.where(author_id: author.id) == author.posts
+        # => true
+
+    Fixes #13506.
+
+    *Lauro Caetano*
+
+*   Calling `delete_all` on an unloaded `CollectionProxy` no longer
+    generates an SQL statement containing each id of the collection:
+
+    Before:
+
+        DELETE FROM `model` WHERE `model`.`parent_id` = 1
+        AND `model`.`id` IN (1, 2, 3...)
+
+    After:
+
+        DELETE FROM `model` WHERE `model`.`parent_id` = 1
+
+    *Eileen M. Uchitelle*, *Aaron Patterson*
+
+*   Fixed error for aggregate methods (`empty?`, `any?`, `count`) with `select`
+    which created invalid SQL.
+
+    Fixes #13648.
+
+    *Simon Woker*
+
+*   PostgreSQL adapter only warns once for every missing OID per connection.
+
+    Fixes #14275.
+
+    *Matthew Draper*, *Yves Senn*
+
+*   PostgreSQL adapter automatically reloads it's type map when encountering
+    unknown OIDs.
+
+    Fixes #14678.
+
+    *Matthew Draper*, *Yves Senn*
+
+*   Fix insertion of records via `has_many :through` association with scope.
+
+    Fixes #3548.
+
+    *Ivan Antropov*
+
+*   Auto-generate stable fixture UUIDs on PostgreSQL.
+
+    Fixes #11524.
+
+    *Roderick van Domburg*
+
+*   Fixed a problem where an enum would overwrite values of another enum
+    with the same name in an unrelated class.
+
+    Fixes #14607.
+
+    *Evan Whalen*
+
+*   PostgreSQL and SQLite string columns no longer have a default limit of 255.
+
+    Fixes #13435, #9153.
+
+    *Vladimir Sazhin*, *Toms Mikoss*, *Yves Senn*
+
+*   Make possible to have an association called `records`.
+
+    Fixes #11645.
+
+    *prathamesh-sonpatki*
+
+*   `to_sql` on an association now matches the query that is actually executed, where it
+    could previously have incorrectly accrued additional conditions (e.g. as a result of
+    a previous query). CollectionProxy now always defers to the association scope's
+    `arel` method so the (incorrect) inherited one should be entirely concealed.
+
+    Fixes #14003.
+
+    *Jefferson Lai*
+
+*   Block a few default Class methods as scope name.
+
+    For instance, this will raise:
+
+        scope :public, -> { where(status: 1) }
+
+    *arthurnn*
+
+*   Fixed error when using `with_options` with lambda.
+
+    Fixes #9805.
+
+    *Lauro Caetano*
+
+*   Switch `sqlite3:///` URLs (which were temporarily
+    deprecated in 4.1) from relative to absolute.
+
+    If you still want the previous interpretation, you should replace
+    `sqlite3:///my/path` with `sqlite3:my/path`.
+
+    *Matthew Draper*
+
+*   Treat blank UUID values as `nil`.
+
+    Example:
+
+        Sample.new(uuid_field: '') #=> <Sample id: nil, uuid_field: nil>
+
+    *Dmitry Lavrov*
+
+*   Enable support for materialized views on PostgreSQL >= 9.3.
+
+    *Dave Lee*
+
+*   The PostgreSQL adapter supports custom domains. Fixes #14305.
+
+    *Yves Senn*
+
+*   PostgreSQL `Column#type` is now determined through the corresponding OID.
+    The column types stay the same except for enum columns. They no longer have
+    `nil` as type but `enum`.
+
+    See #7814.
+
+    *Yves Senn*
+
+*   Fixed error when specifying a non-empty default value on a PostgreSQL array column.
+
+    Fixes #10613.
+
+    *Luke Steensen*
+
+*   Fixed error where .persisted? throws SystemStackError for an unsaved model with a
+    custom primary key that didn't save due to validation error.
+
+    Fixes #14393.
+
+    *Chris Finne*
+
+*   Introduce `validate` as an alias for `valid?`.
+
+    This is more intuitive when you want to run validations but don't care about the return value.
+
+    *Henrik Nyh*
+
+*   Create indexes inline in CREATE TABLE for MySQL.
+
+    This is important, because adding an index on a temporary table after it has been created
+    would commit the transaction.
+
+    It also allows creating and dropping indexed tables with fewer queries and fewer permissions
+    required.
+
+    Example:
+
+        create_table :temp, temporary: true, as: "SELECT id, name, zip FROM a_really_complicated_query" do |t|
+          t.index :zip
+        end
+        # => CREATE TEMPORARY TABLE temp (INDEX (zip)) AS SELECT id, name, zip FROM a_really_complicated_query
+
+    *Cody Cutrer*, *Steve Rice*, *Rafael Mendonça Franca*
+
+*   Use singular table name in generated migrations when
+    `ActiveRecord::Base.pluralize_table_names` is `false`.
+
+    Fixes #13426.
+
+    *Kuldeep Aggarwal*
+
+*   `touch` accepts many attributes to be touched at once.
+
+    Example:
+
+        # touches :signed_at, :sealed_at, and :updated_at/on attributes.
+        Photo.last.touch(:signed_at, :sealed_at)
+
+    *James Pinto*
+
+*   `rake db:structure:dump` only dumps schema information if the schema
+    migration table exists.
+
+    Fixes #14217.
+
+    *Yves Senn*
+
+*   Reap connections that were checked out by now-dead threads, instead
+    of waiting until they disconnect by themselves. Before this change,
+    a suitably constructed series of short-lived threads could starve
+    the connection pool, without ever having more than a couple alive at
+    the same time.
+
+    *Matthew Draper*
+
+*   `pk_and_sequence_for` now ensures that only the pg_depend entries
+    pointing to pg_class, and thus only sequence objects, are considered.
+
+    *Josh Williams*
+
+*   `where.not` adds `references` for `includes` like normal `where` calls do.
+
+    Fixes #14406.
+
+    *Yves Senn*
+
+*   Extend fixture `$LABEL` replacement to allow string interpolation.
+
+    Example:
+
+        martin:
+          email: $LABEL@email.com
+
+        users(:martin).email # => martin@email.com
+
+    *Eric Steele*
+
+*   Add support for `Relation` be passed as parameter on `QueryCache#select_all`.
+
+    Fixes #14361.
+
+    *arthurnn*
+
+*   Passing an Active Record object to `find` or `exists?` is now deprecated.
+    Call `.id` on the object first.
+
+    *Aaron Patterson*
+
+*   Only use BINARY for MySQL case sensitive uniqueness check when column has a case insensitive collation.
+
+    *Ryuta Kamizono*
+
+*   Support for MySQL 5.6 fractional seconds.
+
+    *arthurnn*, *Tatsuhiko Miyagawa*
+
+*   Support for Postgres `citext` data type enabling case-insensitive where
+    values without needing to wrap in UPPER/LOWER sql functions.
+
+    *Troy Kruthoff*, *Lachlan Sylvester*
+
+*   Only save has_one associations if record has changes.
+    Previously after save related callbacks, such as `#after_commit`, were triggered when the has_one
+    object did not get saved to the db.
+
+    *Alan Kennedy*
+
+*   Allow strings to specify the `#order` value.
+
+    Example:
+
+        Model.order(id: 'asc').to_sql == Model.order(id: :asc).to_sql
+
+    *Marcelo Casiraghi*, *Robin Dupret*
+
+*   Dynamically register PostgreSQL enum OIDs. This prevents "unknown OID"
+    warnings on enum columns.
+
+    *Dieter Komendera*
+
+*   `includes` is able to detect the right preloading strategy when string
+    joins are involved.
+
+    Fixes #14109.
+
+    *Aaron Patterson*, *Yves Senn*
+
+*   Fixed error with validation with enum fields for records where the
+    value for any enum attribute is always evaluated as 0 during
+    uniqueness validation.
+
+    Fixes #14172.
+
+    *Vilius Luneckas* *Ahmed AbouElhamayed*
+
+*   `before_add` callbacks are fired before the record is saved on
+    `has_and_belongs_to_many` associations *and* on `has_many :through`
+    associations.  Before this change, `before_add` callbacks would be fired
+    before the record was saved on `has_and_belongs_to_many` associations, but
+    *not* on `has_many :through` associations.
+
+    Fixes #14144.
+
+*   Fixed STI classes not defining an attribute method if there is a
+    conflicting private method defined on its ancestors.
+
+    Fixes #11569.
+
+    *Godfrey Chan*
+
+*   Coerce strings when reading attributes. Fixes #10485.
+
+    Example:
+
+        book = Book.new(title: 12345)
+        book.save!
+        book.title # => "12345"
+
+    *Yves Senn*
+
+*   Deprecate half-baked support for PostgreSQL range values with excluding beginnings.
+    We currently map PostgreSQL ranges to Ruby ranges. This conversion is not fully
+    possible because the Ruby range does not support excluded beginnings.
+
+    The current solution of incrementing the beginning is not correct and is now
+    deprecated. For subtypes where we don't know how to increment (e.g. `#succ`
+    is not defined) it will raise an ArgumentException for ranges with excluding
+    beginnings.
+
+    *Yves Senn*
+
+*   Support for user created range types in PostgreSQL.
+
+    *Yves Senn*
+
+Please check [4-1-stable](https://github.com/rails/rails/blob/4-1-stable/activerecord/CHANGELOG.md) for previous changes.
diff --git a/activerecord/MIT-LICENSE b/activerecord/MIT-LICENSE
new file mode 100644
index 0000000000..2950f05b11
--- /dev/null
+++ b/activerecord/MIT-LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2004-2014 David Heinemeier Hansson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/activerecord/README.rdoc b/activerecord/README.rdoc
new file mode 100644
index 0000000000..f4777919d3
--- /dev/null
+++ b/activerecord/README.rdoc
@@ -0,0 +1,218 @@
+= Active Record -- Object-relational mapping in Rails
+
+Active Record connects classes to relational database tables to establish an
+almost zero-configuration persistence layer for applications. The library
+provides a base class that, when subclassed, sets up a mapping between the new
+class and an existing table in the database. In the context of an application,
+these classes are commonly referred to as *models*. Models can also be
+connected to other models; this is done by defining *associations*.
+
+Active Record relies heavily on naming in that it uses class and association
+names to establish mappings between respective database tables and foreign key
+columns. Although these mappings can be defined explicitly, it's recommended
+to follow naming conventions, especially when getting started with the
+library.
+
+A short rundown of some of the major features:
+
+* Automated mapping between classes and tables, attributes and columns.
+
+   class Product < ActiveRecord::Base
+   end
+
+  {Learn more}[link:classes/ActiveRecord/Base.html]
+
+The Product class is automatically mapped to the table named "products",
+which might look like this:
+
+   CREATE TABLE products (
+     id int(11) NOT NULL auto_increment,
+     name varchar(255),
+     PRIMARY KEY  (id)
+   );
+
+This would also define the following accessors: `Product#name` and
+`Product#name=(new_name)`.
+
+
+* Associations between objects defined by simple class methods.
+
+   class Firm < ActiveRecord::Base
+     has_many   :clients
+     has_one    :account
+     belongs_to :conglomerate
+   end
+
+  {Learn more}[link:classes/ActiveRecord/Associations/ClassMethods.html]
+
+
+* Aggregations of value objects.
+
+   class Account < ActiveRecord::Base
+     composed_of :balance, class_name: 'Money',
+                 mapping: %w(balance amount)
+     composed_of :address,
+                 mapping: [%w(address_street street), %w(address_city city)]
+   end
+
+  {Learn more}[link:classes/ActiveRecord/Aggregations/ClassMethods.html]
+
+
+* Validation rules that can differ for new or existing objects.
+
+    class Account < ActiveRecord::Base
+      validates :subdomain, :name, :email_address, :password, presence: true
+      validates :subdomain, uniqueness: true
+      validates :terms_of_service, acceptance: true, on: :create
+      validates :password, :email_address, confirmation: true, on: :create
+    end
+
+  {Learn more}[link:classes/ActiveRecord/Validations.html]
+
+
+* Callbacks available for the entire life cycle (instantiation, saving, destroying, validating, etc.).
+
+   class Person < ActiveRecord::Base
+     before_destroy :invalidate_payment_plan
+     # the `invalidate_payment_plan` method gets called just before Person#destroy
+   end
+
+  {Learn more}[link:classes/ActiveRecord/Callbacks.html]
+
+
+* Inheritance hierarchies.
+
+   class Company < ActiveRecord::Base; end
+   class Firm < Company; end
+   class Client < Company; end
+   class PriorityClient < Client; end
+
+  {Learn more}[link:classes/ActiveRecord/Base.html]
+
+
+* Transactions.
+
+    # Database transaction
+    Account.transaction do
+      david.withdrawal(100)
+      mary.deposit(100)
+    end
+
+  {Learn more}[link:classes/ActiveRecord/Transactions/ClassMethods.html]
+
+
+* Reflections on columns, associations, and aggregations.
+
+    reflection = Firm.reflect_on_association(:clients)
+    reflection.klass # => Client (class)
+    Firm.columns # Returns an array of column descriptors for the firms table
+
+  {Learn more}[link:classes/ActiveRecord/Reflection/ClassMethods.html]
+
+
+* Database abstraction through simple adapters.
+
+    # connect to SQLite3
+    ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: 'dbfile.sqlite3')
+
+    # connect to MySQL with authentication
+    ActiveRecord::Base.establish_connection(
+      adapter:  'mysql2',
+      host:     'localhost',
+      username: 'me',
+      password: 'secret',
+      database: 'activerecord'
+    )
+
+  {Learn more}[link:classes/ActiveRecord/Base.html] and read about the built-in support for
+  MySQL[link:classes/ActiveRecord/ConnectionAdapters/MysqlAdapter.html],
+  PostgreSQL[link:classes/ActiveRecord/ConnectionAdapters/PostgreSQLAdapter.html], and
+  SQLite3[link:classes/ActiveRecord/ConnectionAdapters/SQLite3Adapter.html].
+
+
+* Logging support for Log4r[https://github.com/colbygk/log4r] and Logger[http://www.ruby-doc.org/stdlib/libdoc/logger/rdoc].
+
+    ActiveRecord::Base.logger = ActiveSupport::Logger.new(STDOUT)
+    ActiveRecord::Base.logger = Log4r::Logger.new('Application Log')
+
+
+* Database agnostic schema management with Migrations.
+
+    class AddSystemSettings < ActiveRecord::Migration
+      def up
+        create_table :system_settings do |t|
+          t.string  :name
+          t.string  :label
+          t.text    :value
+          t.string  :type
+          t.integer :position
+        end
+
+        SystemSetting.create name: 'notice', label: 'Use notice?', value: 1
+      end
+
+      def down
+        drop_table :system_settings
+      end
+    end
+
+  {Learn more}[link:classes/ActiveRecord/Migration.html]
+
+
+== Philosophy
+
+Active Record is an implementation of the object-relational mapping (ORM)
+pattern[http://www.martinfowler.com/eaaCatalog/activeRecord.html] by the same
+name described by Martin Fowler:
+
+  "An object that wraps a row in a database table or view,
+  encapsulates the database access, and adds domain logic on that data."
+
+Active Record attempts to provide a coherent wrapper as a solution for the inconvenience that is
+object-relational mapping. The prime directive for this mapping has been to minimize
+the amount of code needed to build a real-world domain model. This is made possible
+by relying on a number of conventions that make it easy for Active Record to infer
+complex relations and structures from a minimal amount of explicit direction.
+
+Convention over Configuration:
+* No XML files!
+* Lots of reflection and run-time extension
+* Magic is not inherently a bad word
+
+Admit the Database:
+* Lets you drop down to SQL for odd cases and performance
+* Doesn't attempt to duplicate or replace data definitions
+
+
+== Download and installation
+
+The latest version of Active Record can be installed with RubyGems:
+
+  % [sudo] gem install activerecord
+
+Source code can be downloaded as part of the Rails project on GitHub:
+
+* https://github.com/rails/rails/tree/master/activerecord
+
+
+== License
+
+Active Record is released under the MIT license:
+
+* http://www.opensource.org/licenses/MIT
+
+
+== Support
+
+API documentation is at:
+
+* http://api.rubyonrails.org
+
+Bug reports can be filed for the Ruby on Rails project here:
+
+* https://github.com/rails/rails/issues
+
+Feature requests should be discussed on the rails-core mailing list here:
+
+* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
+
diff --git a/activerecord/RUNNING_UNIT_TESTS.rdoc b/activerecord/RUNNING_UNIT_TESTS.rdoc
new file mode 100644
index 0000000000..ca1f2fd665
--- /dev/null
+++ b/activerecord/RUNNING_UNIT_TESTS.rdoc
@@ -0,0 +1,44 @@
+== Setup
+
+If you don't have an environment for running tests, read
+http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#setting-up-a-development-environment
+
+== Running the Tests
+
+To run a specific test:
+
+  $ ruby -Itest test/cases/base_test.rb -n method_name
+
+To run a set of tests:
+
+  $ ruby -Itest test/cases/base_test.rb
+
+You can also run tests that depend upon a specific database backend. For
+example:
+
+  $ bundle exec rake test_sqlite3
+
+Simply executing <tt>bundle exec rake test</tt> is equivalent to the following:
+
+  $ bundle exec rake test_mysql
+  $ bundle exec rake test_mysql2
+  $ bundle exec rake test_postgresql
+  $ bundle exec rake test_sqlite3
+  $ bundle exec rake test_sqlite3_mem
+
+There should be tests available for each database backend listed in the {Config
+File}[rdoc-label:label-Config+File]. (the exact set of available tests is
+defined in +Rakefile+)
+
+== Config File
+
+If +test/config.yml+ is present, it's parameters are obeyed. Otherwise, the
+parameters in +test/config.example.yml+ are obeyed.
+
+You can override the +connections:+ parameter in either file using the +ARCONN+
+(Active Record CONNection) environment variable:
+
+  $ ARCONN=postgresql ruby -Itest test/cases/base_test.rb
+
+You can specify a custom location for the config file using the +ARCONFIG+
+environment variable.
diff --git a/activerecord/Rakefile b/activerecord/Rakefile
new file mode 100644
index 0000000000..7769966a22
--- /dev/null
+++ b/activerecord/Rakefile
@@ -0,0 +1,185 @@
+require 'rake/testtask'
+require 'rubygems/package_task'
+
+require File.expand_path(File.dirname(__FILE__)) + "/test/config"
+require File.expand_path(File.dirname(__FILE__)) + "/test/support/config"
+
+def run_without_aborting(*tasks)
+  errors = []
+
+  tasks.each do |task|
+    begin
+      Rake::Task[task].invoke
+    rescue Exception
+      errors << task
+    end
+  end
+
+  abort "Errors running #{errors.join(', ')}" if errors.any?
+end
+
+desc 'Run mysql, mysql2, sqlite, and postgresql tests by default'
+task :default => :test
+
+desc 'Run mysql, mysql2, sqlite, and postgresql tests'
+task :test do
+  tasks = defined?(JRUBY_VERSION) ?
+    %w(test_jdbcmysql test_jdbcsqlite3 test_jdbcpostgresql) :
+    %w(test_mysql test_mysql2 test_sqlite3 test_postgresql)
+  run_without_aborting(*tasks)
+end
+
+namespace :test do
+  task :isolated do
+    tasks = defined?(JRUBY_VERSION) ?
+      %w(isolated_test_jdbcmysql isolated_test_jdbcsqlite3 isolated_test_jdbcpostgresql) :
+      %w(isolated_test_mysql isolated_test_mysql2 isolated_test_sqlite3 isolated_test_postgresql)
+    run_without_aborting(*tasks)
+  end
+end
+
+desc 'Build MySQL and PostgreSQL test databases'
+namespace :db do
+  task :create => ['db:mysql:build', 'db:postgresql:build']
+  task :drop => ['db:mysql:drop', 'db:postgresql:drop']
+end
+
+%w( mysql mysql2 postgresql sqlite3 sqlite3_mem db2 oracle jdbcmysql jdbcpostgresql jdbcsqlite3 jdbcderby jdbch2 jdbchsqldb ).each do |adapter|
+  namespace :test do
+    Rake::TestTask.new(adapter => "#{adapter}:env") { |t|
+      adapter_short = adapter == 'db2' ? adapter : adapter[/^[a-z0-9]+/]
+      t.libs << 'test'
+      t.test_files = (Dir.glob( "test/cases/**/*_test.rb" ).reject {
+        |x| x =~ /\/adapters\//
+      } + Dir.glob("test/cases/adapters/#{adapter_short}/**/*_test.rb")).sort
+
+      t.warning = true
+      t.verbose = true
+    }
+
+    namespace :isolated do
+      task adapter => "#{adapter}:env" do
+        adapter_short = adapter == 'db2' ? adapter : adapter[/^[a-z0-9]+/]
+        puts [adapter, adapter_short].inspect
+        (Dir["test/cases/**/*_test.rb"].reject {
+          |x| x =~ /\/adapters\//
+        } + Dir["test/cases/adapters/#{adapter_short}/**/*_test.rb"]).all? do |file|
+          sh(Gem.ruby, '-w' ,"-Itest", file)
+        end or raise "Failures"
+      end
+    end
+  end
+
+  namespace adapter do
+    task :test => "test_#{adapter}"
+    task :isolated_test => "isolated_test_#{adapter}"
+
+    # Set the connection environment for the adapter
+    task(:env) { ENV['ARCONN'] = adapter }
+  end
+
+  # Make sure the adapter test evaluates the env setting task
+  task "test_#{adapter}" => ["#{adapter}:env", "test:#{adapter}"]
+  task "isolated_test_#{adapter}" => ["#{adapter}:env", "test:isolated:#{adapter}"]
+end
+
+rule '.sqlite3' do |t|
+  sh %Q{sqlite3 "#{t.name}" "create table a (a integer); drop table a;"}
+end
+
+task :test_sqlite3 => [
+  'test/fixtures/fixture_database.sqlite3',
+  'test/fixtures/fixture_database_2.sqlite3'
+]
+
+namespace :db do
+  namespace :mysql do
+    desc 'Build the MySQL test databases'
+    task :build do
+      config = ARTest.config['connections']['mysql']
+      %x( mysql --user=#{config['arunit']['username']} -e "create DATABASE #{config['arunit']['database']} DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_unicode_ci ")
+      %x( mysql --user=#{config['arunit2']['username']} -e "create DATABASE #{config['arunit2']['database']} DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_unicode_ci ")
+    end
+
+    desc 'Drop the MySQL test databases'
+    task :drop do
+      config = ARTest.config['connections']['mysql']
+      %x( mysqladmin --user=#{config['arunit']['username']} -f drop #{config['arunit']['database']} )
+      %x( mysqladmin --user=#{config['arunit2']['username']} -f drop #{config['arunit2']['database']} )
+    end
+
+    desc 'Rebuild the MySQL test databases'
+    task :rebuild => [:drop, :build]
+  end
+
+  namespace :postgresql do
+    desc 'Build the PostgreSQL test databases'
+    task :build do
+      config = ARTest.config['connections']['postgresql']
+      %x( createdb -E UTF8 -T template0 #{config['arunit']['database']} )
+      %x( createdb -E UTF8 -T template0 #{config['arunit2']['database']} )
+
+      # prepare hstore
+      if %x( createdb --version ).strip.gsub(/(.*)(\d\.\d\.\d)$/, "\\2") < "9.1.0"
+        puts "Please prepare hstore data type. See http://www.postgresql.org/docs/9.0/static/hstore.html"
+      end
+    end
+
+    desc 'Drop the PostgreSQL test databases'
+    task :drop do
+      config = ARTest.config['connections']['postgresql']
+      %x( dropdb #{config['arunit']['database']} )
+      %x( dropdb #{config['arunit2']['database']} )
+    end
+
+    desc 'Rebuild the PostgreSQL test databases'
+    task :rebuild => [:drop, :build]
+  end
+end
+
+task :build_mysql_databases => 'db:mysql:build'
+task :drop_mysql_databases => 'db:mysql:drop'
+task :rebuild_mysql_databases => 'db:mysql:rebuild'
+
+task :build_postgresql_databases => 'db:postgresql:build'
+task :drop_postgresql_databases => 'db:postgresql:drop'
+task :rebuild_postgresql_databases => 'db:postgresql:rebuild'
+
+task :lines do
+  lines, codelines, total_lines, total_codelines = 0, 0, 0, 0
+
+  FileList["lib/active_record/**/*.rb"].each do |file_name|
+    next if file_name =~ /vendor/
+    File.open(file_name, 'r') do |f|
+      while line = f.gets
+        lines += 1
+        next if line =~ /^\s*$/
+        next if line =~ /^\s*#/
+        codelines += 1
+      end
+    end
+    puts "L: #{sprintf("%4d", lines)}, LOC #{sprintf("%4d", codelines)} | #{file_name}"
+
+    total_lines     += lines
+    total_codelines += codelines
+
+    lines, codelines = 0, 0
+  end
+
+  puts "Total: Lines #{total_lines}, LOC #{total_codelines}"
+end
+
+spec = eval(File.read('activerecord.gemspec'))
+
+Gem::PackageTask.new(spec) do |p|
+  p.gem_spec = spec
+end
+
+# Publishing ------------------------------------------------------
+
+desc "Release to rubygems"
+task :release => :package do
+  require 'rake/gemcutter'
+  Rake::Gemcutter::Tasks.new(spec).define
+  Rake::Task['gem:push'].invoke
+end
diff --git a/activerecord/activerecord.gemspec b/activerecord/activerecord.gemspec
new file mode 100644
index 0000000000..8075008574
--- /dev/null
+++ b/activerecord/activerecord.gemspec
@@ -0,0 +1,28 @@
+version = File.read(File.expand_path('../../RAILS_VERSION', __FILE__)).strip
+
+Gem::Specification.new do |s|
+  s.platform    = Gem::Platform::RUBY
+  s.name        = 'activerecord'
+  s.version     = version
+  s.summary     = 'Object-relational mapper framework (part of Rails).'
+  s.description = 'Databases on Rails. Build a persistent domain model by mapping database tables to Ruby classes. Strong conventions for associations, validations, aggregations, migrations, and testing come baked-in.'
+
+  s.required_ruby_version = '>= 1.9.3'
+
+  s.license = 'MIT'
+
+  s.author   = 'David Heinemeier Hansson'
+  s.email    = 'david@loudthinking.com'
+  s.homepage = 'http://www.rubyonrails.org'
+
+  s.files        = Dir['CHANGELOG.md', 'MIT-LICENSE', 'README.rdoc', 'examples/**/*', 'lib/**/*']
+  s.require_path = 'lib'
+
+  s.extra_rdoc_files = %w(README.rdoc)
+  s.rdoc_options.concat ['--main',  'README.rdoc']
+
+  s.add_dependency 'activesupport', version
+  s.add_dependency 'activemodel',   version
+
+  s.add_dependency 'arel', '~> 6.0.0'
+end
diff --git a/activerecord/examples/.gitignore b/activerecord/examples/.gitignore
new file mode 100644
index 0000000000..0dfc1cb7fb
--- /dev/null
+++ b/activerecord/examples/.gitignore
@@ -0,0 +1 @@
+performance.sql
diff --git a/activerecord/examples/performance.rb b/activerecord/examples/performance.rb
new file mode 100644
index 0000000000..d3546ce948
--- /dev/null
+++ b/activerecord/examples/performance.rb
@@ -0,0 +1,184 @@
+require File.expand_path('../../../load_paths', __FILE__)
+require "active_record"
+require 'benchmark/ips'
+
+TIME    = (ENV['BENCHMARK_TIME'] || 20).to_i
+RECORDS = (ENV['BENCHMARK_RECORDS'] || TIME*1000).to_i
+
+conn = { adapter: 'sqlite3', database: ':memory:' }
+
+ActiveRecord::Base.establish_connection(conn)
+
+class User < ActiveRecord::Base
+  connection.create_table :users, force: true do |t|
+    t.string :name, :email
+    t.timestamps
+  end
+
+  has_many :exhibits
+end
+
+class Exhibit < ActiveRecord::Base
+  connection.create_table :exhibits, force: true do |t|
+    t.belongs_to :user
+    t.string :name
+    t.text :notes
+    t.timestamps
+  end
+
+  belongs_to :user
+
+  def look; attributes end
+  def feel; look; user.name end
+
+  def self.with_name
+    where("name IS NOT NULL")
+  end
+
+  def self.with_notes
+    where("notes IS NOT NULL")
+  end
+
+  def self.look(exhibits) exhibits.each { |e| e.look } end
+  def self.feel(exhibits) exhibits.each { |e| e.feel } end
+end
+
+def progress_bar(int); print "." if (int%100).zero? ; end
+
+puts 'Generating data...'
+
+module ActiveRecord
+  class Faker
+    LOREM = %Q{Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse non aliquet diam. Curabitur vel urna metus, quis malesuada elit.
+     Integer consequat tincidunt felis. Etiam non erat dolor. Vivamus imperdiet nibh sit amet diam eleifend id posuere diam malesuada. Mauris at accumsan sem.
+     Donec id lorem neque. Fusce erat lorem, ornare eu congue vitae, malesuada quis neque. Maecenas vel urna a velit pretium fermentum. Donec tortor enim,
+     tempor venenatis egestas a, tempor sed ipsum. Ut arcu justo, faucibus non imperdiet ac, interdum at diam. Pellentesque ipsum enim, venenatis ut iaculis vitae,
+     varius vitae sem. Sed rutrum quam ac elit euismod bibendum. Donec ultricies ultricies magna, at lacinia libero mollis aliquam. Sed ac arcu in tortor elementum
+     tincidunt vel interdum sem. Curabitur eget erat arcu. Praesent eget eros leo. Nam magna enim, sollicitudin vehicula scelerisque in, vulputate ut libero.
+     Praesent varius tincidunt commodo}.split
+
+    def self.name
+      LOREM.grep(/^\w*$/).sort_by { rand }.first(2).join ' '
+    end
+
+    def self.email
+      LOREM.grep(/^\w*$/).sort_by { rand }.first(2).join('@') + ".com"
+    end
+  end
+end
+
+# pre-compute the insert statements and fake data compilation,
+# so the benchmarks below show the actual runtime for the execute
+# method, minus the setup steps
+
+# Using the same paragraph for all exhibits because it is very slow
+# to generate unique paragraphs for all exhibits.
+notes = ActiveRecord::Faker::LOREM.join ' '
+today = Date.today
+
+puts "Inserting #{RECORDS} users and exhibits..."
+RECORDS.times do |record|
+  user = User.create(
+    created_at: today,
+    name: ActiveRecord::Faker.name,
+    email: ActiveRecord::Faker.email
+  )
+
+  Exhibit.create(
+    created_at: today,
+    name: ActiveRecord::Faker.name,
+    user: user,
+    notes: notes
+  )
+  progress_bar(record)
+end
+puts "Done!\n"
+
+Benchmark.ips(TIME) do |x|
+  ar_obj       = Exhibit.find(1)
+  attrs        = { name: 'sam' }
+  attrs_first  = { name: 'sam' }
+  attrs_second = { name: 'tom' }
+  exhibit      = {
+    name: ActiveRecord::Faker.name,
+    notes: notes,
+    created_at: Date.today
+  }
+
+  x.report("Model#id") do
+    ar_obj.id
+  end
+
+  x.report 'Model.new (instantiation)' do
+    Exhibit.new
+  end
+
+  x.report 'Model.new (setting attributes)' do
+    Exhibit.new(attrs)
+  end
+
+  x.report 'Model.first' do
+    Exhibit.first.look
+  end
+
+  x.report 'Model.take' do 
+    Exhibit.take
+  end
+  
+  x.report("Model.all limit(100)") do
+    Exhibit.look Exhibit.limit(100)
+  end
+
+  x.report("Model.all take(100)") do
+    Exhibit.look Exhibit.take(100)
+  end
+
+  x.report "Model.all limit(100) with relationship" do
+    Exhibit.feel Exhibit.limit(100).includes(:user)
+  end
+
+  x.report "Model.all limit(10,000)" do
+    Exhibit.look Exhibit.limit(10000)
+  end
+
+  x.report 'Model.named_scope' do
+    Exhibit.limit(10).with_name.with_notes
+  end
+
+  x.report 'Model.create' do
+    Exhibit.create(exhibit)
+  end
+
+  x.report 'Resource#attributes=' do
+    e = Exhibit.new(attrs_first)
+    e.attributes = attrs_second
+  end
+
+  x.report 'Resource#update' do
+    Exhibit.first.update(name: 'bob')
+  end
+
+  x.report 'Resource#destroy' do
+    Exhibit.first.destroy
+  end
+
+  x.report 'Model.transaction' do
+    Exhibit.transaction { Exhibit.new }
+  end
+
+  x.report 'Model.find(id)' do
+    User.find(1)
+  end
+
+  x.report 'Model.find_by_sql' do
+    Exhibit.find_by_sql("SELECT * FROM exhibits WHERE id = #{(rand * 1000 + 1).to_i}").first
+  end
+
+  x.report "Model.log" do
+    Exhibit.connection.send(:log, "hello", "world") {}
+  end
+
+  x.report "AR.execute(query)" do
+    ActiveRecord::Base.connection.execute("SELECT * FROM exhibits WHERE id = #{(rand * 1000 + 1).to_i}")
+  end
+end
diff --git a/activerecord/examples/simple.rb b/activerecord/examples/simple.rb
new file mode 100644
index 0000000000..4ed5d80eb2
--- /dev/null
+++ b/activerecord/examples/simple.rb
@@ -0,0 +1,14 @@
+require File.expand_path('../../../load_paths', __FILE__)
+require 'active_record'
+
+class Person < ActiveRecord::Base
+  establish_connection adapter: 'sqlite3', database: 'foobar.db'
+  connection.create_table table_name, force: true do |t|
+    t.string :name
+  end
+end
+
+bob = Person.create!(name: 'bob')
+puts Person.all.inspect
+bob.destroy
+puts Person.all.inspect
diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
new file mode 100644
index 0000000000..9028970a3d
--- /dev/null
+++ b/activerecord/lib/active_record.rb
@@ -0,0 +1,173 @@
+#--
+# Copyright (c) 2004-2014 David Heinemeier Hansson
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#++
+
+require 'active_support'
+require 'active_support/rails'
+require 'active_model'
+require 'arel'
+
+require 'active_record/version'
+require 'active_record/attribute_set'
+
+module ActiveRecord
+  extend ActiveSupport::Autoload
+
+  autoload :Attribute
+  autoload :Base
+  autoload :Callbacks
+  autoload :Core
+  autoload :ConnectionHandling
+  autoload :CounterCache
+  autoload :DynamicMatchers
+  autoload :Enum
+  autoload :Explain
+  autoload :Inheritance
+  autoload :Integration
+  autoload :Migration
+  autoload :Migrator, 'active_record/migration'
+  autoload :ModelSchema
+  autoload :NestedAttributes
+  autoload :NoTouching
+  autoload :Persistence
+  autoload :QueryCache
+  autoload :Querying
+  autoload :ReadonlyAttributes
+  autoload :Reflection
+  autoload :RuntimeRegistry
+  autoload :Sanitization
+  autoload :Schema
+  autoload :SchemaDumper
+  autoload :SchemaMigration
+  autoload :Scoping
+  autoload :Serialization
+  autoload :StatementCache
+  autoload :Store
+  autoload :Timestamp
+  autoload :Transactions
+  autoload :Translation
+  autoload :Validations
+
+  eager_autoload do
+    autoload :ActiveRecordError, 'active_record/errors'
+    autoload :ConnectionNotEstablished, 'active_record/errors'
+    autoload :ConnectionAdapters, 'active_record/connection_adapters/abstract_adapter'
+
+    autoload :Aggregations
+    autoload :Associations
+    autoload :AttributeAssignment
+    autoload :AttributeMethods
+    autoload :AutosaveAssociation
+
+    autoload :Relation
+    autoload :AssociationRelation
+    autoload :NullRelation
+
+    autoload_under 'relation' do
+      autoload :QueryMethods
+      autoload :FinderMethods
+      autoload :Calculations
+      autoload :PredicateBuilder
+      autoload :SpawnMethods
+      autoload :Batches
+      autoload :Delegation
+    end
+
+    autoload :Result
+  end
+
+  module Coders
+    autoload :YAMLColumn, 'active_record/coders/yaml_column'
+    autoload :JSON, 'active_record/coders/json'
+  end
+
+  module AttributeMethods
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :BeforeTypeCast
+      autoload :Dirty
+      autoload :PrimaryKey
+      autoload :Query
+      autoload :Read
+      autoload :TimeZoneConversion
+      autoload :Write
+      autoload :Serialization
+    end
+  end
+
+  module Locking
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :Optimistic
+      autoload :Pessimistic
+    end
+  end
+
+  module ConnectionAdapters
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :AbstractAdapter
+      autoload :ConnectionManagement, "active_record/connection_adapters/abstract/connection_pool"
+    end
+  end
+
+  module Scoping
+    extend ActiveSupport::Autoload
+
+    eager_autoload do
+      autoload :Named
+      autoload :Default
+    end
+  end
+
+  module Tasks
+    extend ActiveSupport::Autoload
+
+    autoload :DatabaseTasks
+    autoload :SQLiteDatabaseTasks, 'active_record/tasks/sqlite_database_tasks'
+    autoload :MySQLDatabaseTasks,  'active_record/tasks/mysql_database_tasks'
+    autoload :PostgreSQLDatabaseTasks,
+      'active_record/tasks/postgresql_database_tasks'
+  end
+
+  autoload :TestFixtures, 'active_record/fixtures'
+
+  def self.eager_load!
+    super
+    ActiveRecord::Locking.eager_load!
+    ActiveRecord::Scoping.eager_load!
+    ActiveRecord::Associations.eager_load!
+    ActiveRecord::AttributeMethods.eager_load!
+    ActiveRecord::ConnectionAdapters.eager_load!
+  end
+end
+
+ActiveSupport.on_load(:active_record) do
+  Arel::Table.engine = self
+end
+
+ActiveSupport.on_load(:i18n) do
+  I18n.load_path << File.dirname(__FILE__) + '/active_record/locale/en.yml'
+end
diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
new file mode 100644
index 0000000000..e576ec4d40
--- /dev/null
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -0,0 +1,266 @@
+module ActiveRecord
+  # = Active Record Aggregations
+  module Aggregations # :nodoc:
+    extend ActiveSupport::Concern
+
+    def clear_aggregation_cache #:nodoc:
+      @aggregation_cache.clear if persisted?
+    end
+
+    # Active Record implements aggregation through a macro-like class method called +composed_of+
+    # for representing attributes  as value objects. It expresses relationships like "Account [is]
+    # composed of Money [among other things]" or "Person [is] composed of [an] address". Each call
+    # to the macro adds a description of how the value objects are created from the attributes of
+    # the entity object (when the entity is initialized either as a new object or from finding an
+    # existing object) and how it can be turned back into attributes (when the entity is saved to
+    # the database).
+    #
+    #   class Customer < ActiveRecord::Base
+    #     composed_of :balance, class_name: "Money", mapping: %w(balance amount)
+    #     composed_of :address, mapping: [ %w(address_street street), %w(address_city city) ]
+    #   end
+    #
+    # The customer class now has the following methods to manipulate the value objects:
+    # * <tt>Customer#balance, Customer#balance=(money)</tt>
+    # * <tt>Customer#address, Customer#address=(address)</tt>
+    #
+    # These methods will operate with value objects like the ones described below:
+    #
+    #  class Money
+    #    include Comparable
+    #    attr_reader :amount, :currency
+    #    EXCHANGE_RATES = { "USD_TO_DKK" => 6 }
+    #
+    #    def initialize(amount, currency = "USD")
+    #      @amount, @currency = amount, currency
+    #    end
+    #
+    #    def exchange_to(other_currency)
+    #      exchanged_amount = (amount * EXCHANGE_RATES["#{currency}_TO_#{other_currency}"]).floor
+    #      Money.new(exchanged_amount, other_currency)
+    #    end
+    #
+    #    def ==(other_money)
+    #      amount == other_money.amount && currency == other_money.currency
+    #    end
+    #
+    #    def <=>(other_money)
+    #      if currency == other_money.currency
+    #        amount <=> other_money.amount
+    #      else
+    #        amount <=> other_money.exchange_to(currency).amount
+    #      end
+    #    end
+    #  end
+    #
+    #  class Address
+    #    attr_reader :street, :city
+    #    def initialize(street, city)
+    #      @street, @city = street, city
+    #    end
+    #
+    #    def close_to?(other_address)
+    #      city == other_address.city
+    #    end
+    #
+    #    def ==(other_address)
+    #      city == other_address.city && street == other_address.street
+    #    end
+    #  end
+    #
+    # Now it's possible to access attributes from the database through the value objects instead. If
+    # you choose to name the composition the same as the attribute's name, it will be the only way to
+    # access that attribute. That's the case with our +balance+ attribute. You interact with the value
+    # objects just like you would with any other attribute:
+    #
+    #   customer.balance = Money.new(20)     # sets the Money value object and the attribute
+    #   customer.balance                     # => Money value object
+    #   customer.balance.exchange_to("DKK")  # => Money.new(120, "DKK")
+    #   customer.balance > Money.new(10)     # => true
+    #   customer.balance == Money.new(20)    # => true
+    #   customer.balance < Money.new(5)      # => false
+    #
+    # Value objects can also be composed of multiple attributes, such as the case of Address. The order
+    # of the mappings will determine the order of the parameters.
+    #
+    #   customer.address_street = "Hyancintvej"
+    #   customer.address_city   = "Copenhagen"
+    #   customer.address        # => Address.new("Hyancintvej", "Copenhagen")
+    #
+    #   customer.address_street = "Vesterbrogade"
+    #   customer.address        # => Address.new("Hyancintvej", "Copenhagen")
+    #   customer.clear_aggregation_cache
+    #   customer.address        # => Address.new("Vesterbrogade", "Copenhagen")
+    #
+    #   customer.address = Address.new("May Street", "Chicago")
+    #   customer.address_street # => "May Street"
+    #   customer.address_city   # => "Chicago"
+    #
+    # == Writing value objects
+    #
+    # Value objects are immutable and interchangeable objects that represent a given value, such as
+    # a Money object representing $5. Two Money objects both representing $5 should be equal (through
+    # methods such as <tt>==</tt> and <tt><=></tt> from Comparable if ranking makes sense). This is
+    # unlike entity objects where equality is determined by identity. An entity class such as Customer can
+    # easily have two different objects that both have an address on Hyancintvej. Entity identity is
+    # determined by object or relational unique identifiers (such as primary keys). Normal
+    # ActiveRecord::Base classes are entity objects.
+    #
+    # It's also important to treat the value objects as immutable. Don't allow the Money object to have
+    # its amount changed after creation. Create a new Money object with the new value instead. The
+    # Money#exchange_to method is an example of this. It returns a new value object instead of changing
+    # its own values. Active Record won't persist value objects that have been changed through means
+    # other than the writer method.
+    #
+    # The immutable requirement is enforced by Active Record by freezing any object assigned as a value
+    # object. Attempting to change it afterwards will result in a RuntimeError.
+    #
+    # Read more about value objects on http://c2.com/cgi/wiki?ValueObject and on the dangers of not
+    # keeping value objects immutable on http://c2.com/cgi/wiki?ValueObjectsShouldBeImmutable
+    #
+    # == Custom constructors and converters
+    #
+    # By default value objects are initialized by calling the <tt>new</tt> constructor of the value
+    # class passing each of the mapped attributes, in the order specified by the <tt>:mapping</tt>
+    # option, as arguments. If the value class doesn't support this convention then +composed_of+ allows
+    # a custom constructor to be specified.
+    #
+    # When a new value is assigned to the value object, the default assumption is that the new value
+    # is an instance of the value class. Specifying a custom converter allows the new value to be automatically
+    # converted to an instance of value class if necessary.
+    #
+    # For example, the NetworkResource model has +network_address+ and +cidr_range+ attributes that should be
+    # aggregated using the NetAddr::CIDR value class (http://www.ruby-doc.org/gems/docs/n/netaddr-1.5.0/NetAddr/CIDR.html).
+    # The constructor for the value class is called +create+ and it expects a CIDR address string as a parameter.
+    # New values can be assigned to the value object using either another NetAddr::CIDR object, a string
+    # or an array. The <tt>:constructor</tt> and <tt>:converter</tt> options can be used to meet
+    # these requirements:
+    #
+    #   class NetworkResource < ActiveRecord::Base
+    #     composed_of :cidr,
+    #                 class_name: 'NetAddr::CIDR',
+    #                 mapping: [ %w(network_address network), %w(cidr_range bits) ],
+    #                 allow_nil: true,
+    #                 constructor: Proc.new { |network_address, cidr_range| NetAddr::CIDR.create("#{network_address}/#{cidr_range}") },
+    #                 converter: Proc.new { |value| NetAddr::CIDR.create(value.is_a?(Array) ? value.join('/') : value) }
+    #   end
+    #
+    #   # This calls the :constructor
+    #   network_resource = NetworkResource.new(network_address: '192.168.0.1', cidr_range: 24)
+    #
+    #   # These assignments will both use the :converter
+    #   network_resource.cidr = [ '192.168.2.1', 8 ]
+    #   network_resource.cidr = '192.168.0.1/24'
+    #
+    #   # This assignment won't use the :converter as the value is already an instance of the value class
+    #   network_resource.cidr = NetAddr::CIDR.create('192.168.2.1/8')
+    #
+    #   # Saving and then reloading will use the :constructor on reload
+    #   network_resource.save
+    #   network_resource.reload
+    #
+    # == Finding records by a value object
+    #
+    # Once a +composed_of+ relationship is specified for a model, records can be loaded from the database
+    # by specifying an instance of the value object in the conditions hash. The following example
+    # finds all customers with +balance_amount+ equal to 20 and +balance_currency+ equal to "USD":
+    #
+    #   Customer.where(balance: Money.new(20, "USD"))
+    #
+    module ClassMethods
+      # Adds reader and writer methods for manipulating a value object:
+      # <tt>composed_of :address</tt> adds <tt>address</tt> and <tt>address=(new_address)</tt> methods.
+      #
+      # Options are:
+      # * <tt>:class_name</tt> - Specifies the class name of the association. Use it only if that name
+      #   can't be inferred from the part id. So <tt>composed_of :address</tt> will by default be linked
+      #   to the Address class, but if the real class name is CompanyAddress, you'll have to specify it
+      #   with this option.
+      # * <tt>:mapping</tt> - Specifies the mapping of entity attributes to attributes of the value
+      #   object. Each mapping is represented as an array where the first item is the name of the
+      #   entity attribute and the second item is the name of the attribute in the value object. The
+      #   order in which mappings are defined determines the order in which attributes are sent to the
+      #   value class constructor.
+      # * <tt>:allow_nil</tt> - Specifies that the value object will not be instantiated when all mapped
+      #   attributes are +nil+. Setting the value object to +nil+ has the effect of writing +nil+ to all
+      #   mapped attributes.
+      #   This defaults to +false+.
+      # * <tt>:constructor</tt> - A symbol specifying the name of the constructor method or a Proc that
+      #   is called to initialize the value object. The constructor is passed all of the mapped attributes,
+      #   in the order that they are defined in the <tt>:mapping option</tt>, as arguments and uses them
+      #   to instantiate a <tt>:class_name</tt> object.
+      #   The default is <tt>:new</tt>.
+      # * <tt>:converter</tt> - A symbol specifying the name of a class method of <tt>:class_name</tt>
+      #   or a Proc that is called when a new value is assigned to the value object. The converter is
+      #   passed the single value that is used in the assignment and is only called if the new value is
+      #   not an instance of <tt>:class_name</tt>. If <tt>:allow_nil</tt> is set to true, the converter
+      #   can return nil to skip the assignment.
+      #
+      # Option examples:
+      #   composed_of :temperature, mapping: %w(reading celsius)
+      #   composed_of :balance, class_name: "Money", mapping: %w(balance amount),
+      #                         converter: Proc.new { |balance| balance.to_money }
+      #   composed_of :address, mapping: [ %w(address_street street), %w(address_city city) ]
+      #   composed_of :gps_location
+      #   composed_of :gps_location, allow_nil: true
+      #   composed_of :ip_address,
+      #               class_name: 'IPAddr',
+      #               mapping: %w(ip to_i),
+      #               constructor: Proc.new { |ip| IPAddr.new(ip, Socket::AF_INET) },
+      #               converter: Proc.new { |ip| ip.is_a?(Integer) ? IPAddr.new(ip, Socket::AF_INET) : IPAddr.new(ip.to_s) }
+      #
+      def composed_of(part_id, options = {})
+        options.assert_valid_keys(:class_name, :mapping, :allow_nil, :constructor, :converter)
+
+        name        = part_id.id2name
+        class_name  = options[:class_name]  || name.camelize
+        mapping     = options[:mapping]     || [ name, name ]
+        mapping     = [ mapping ] unless mapping.first.is_a?(Array)
+        allow_nil   = options[:allow_nil]   || false
+        constructor = options[:constructor] || :new
+        converter   = options[:converter]
+
+        reader_method(name, class_name, mapping, allow_nil, constructor)
+        writer_method(name, class_name, mapping, allow_nil, converter)
+
+        reflection = ActiveRecord::Reflection.create(:composed_of, part_id, nil, options, self)
+        Reflection.add_aggregate_reflection self, part_id, reflection
+      end
+
+      private
+        def reader_method(name, class_name, mapping, allow_nil, constructor)
+          define_method(name) do
+            if @aggregation_cache[name].nil? && (!allow_nil || mapping.any? {|key, _| !read_attribute(key).nil? })
+              attrs = mapping.collect {|key, _| read_attribute(key)}
+              object = constructor.respond_to?(:call) ?
+                constructor.call(*attrs) :
+                class_name.constantize.send(constructor, *attrs)
+              @aggregation_cache[name] = object
+            end
+            @aggregation_cache[name]
+          end
+        end
+
+        def writer_method(name, class_name, mapping, allow_nil, converter)
+          define_method("#{name}=") do |part|
+            klass = class_name.constantize
+            if part.is_a?(Hash)
+              part = klass.new(*part.values)
+            end
+
+            unless part.is_a?(klass) || converter.nil? || part.nil?
+              part = converter.respond_to?(:call) ? converter.call(part) : klass.send(converter, part)
+            end
+
+            if part.nil? && allow_nil
+              mapping.each { |key, _| self[key] = nil }
+              @aggregation_cache[name] = nil
+            else
+              mapping.each { |key, value| self[key] = part.send(value) }
+              @aggregation_cache[name] = part.freeze
+            end
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/association_relation.rb b/activerecord/lib/active_record/association_relation.rb
new file mode 100644
index 0000000000..5a84792f45
--- /dev/null
+++ b/activerecord/lib/active_record/association_relation.rb
@@ -0,0 +1,22 @@
+module ActiveRecord
+  class AssociationRelation < Relation
+    def initialize(klass, table, association)
+      super(klass, table)
+      @association = association
+    end
+
+    def proxy_association
+      @association
+    end
+
+    def ==(other)
+      other == to_a
+    end
+
+    private
+
+    def exec_queries
+      super.each { |r| @association.set_inverse_instance r }
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
new file mode 100644
index 0000000000..1c5a737696
--- /dev/null
+++ b/activerecord/lib/active_record/associations.rb
@@ -0,0 +1,1630 @@
+require 'active_support/core_ext/enumerable'
+require 'active_support/core_ext/string/conversions'
+require 'active_support/core_ext/module/remove_method'
+require 'active_record/errors'
+
+module ActiveRecord
+  class AssociationNotFoundError < ConfigurationError #:nodoc:
+    def initialize(record, association_name)
+      super("Association named '#{association_name}' was not found on #{record.class.name}; perhaps you misspelled it?")
+    end
+  end
+
+  class InverseOfAssociationNotFoundError < ActiveRecordError #:nodoc:
+    def initialize(reflection, associated_class = nil)
+      super("Could not find the inverse association for #{reflection.name} (#{reflection.options[:inverse_of].inspect} in #{associated_class.nil? ? reflection.class_name : associated_class.name})")
+    end
+  end
+
+  class HasManyThroughAssociationNotFoundError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name, reflection)
+      super("Could not find the association #{reflection.options[:through].inspect} in model #{owner_class_name}")
+    end
+  end
+
+  class HasManyThroughAssociationPolymorphicSourceError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name, reflection, source_reflection)
+      super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' on the polymorphic object '#{source_reflection.class_name}##{source_reflection.name}' without 'source_type'. Try adding 'source_type: \"#{reflection.name.to_s.classify}\"' to 'has_many :through' definition.")
+    end
+  end
+
+  class HasManyThroughAssociationPolymorphicThroughError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name, reflection)
+      super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' which goes through the polymorphic association '#{owner_class_name}##{reflection.through_reflection.name}'.")
+    end
+  end
+
+  class HasManyThroughAssociationPointlessSourceTypeError < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name, reflection, source_reflection)
+      super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' with a :source_type option if the '#{reflection.through_reflection.class_name}##{source_reflection.name}' is not polymorphic. Try removing :source_type on your association.")
+    end
+  end
+
+  class HasOneThroughCantAssociateThroughCollection < ActiveRecordError #:nodoc:
+    def initialize(owner_class_name, reflection, through_reflection)
+      super("Cannot have a has_one :through association '#{owner_class_name}##{reflection.name}' where the :through association '#{owner_class_name}##{through_reflection.name}' is a collection. Specify a has_one or belongs_to association in the :through option instead.")
+    end
+  end
+
+  class HasManyThroughSourceAssociationNotFoundError < ActiveRecordError #:nodoc:
+    def initialize(reflection)
+      through_reflection      = reflection.through_reflection
+      source_reflection_names = reflection.source_reflection_names
+      source_associations     = reflection.through_reflection.klass._reflections.keys
+      super("Could not find the source association(s) #{source_reflection_names.collect{ |a| a.inspect }.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)} in model #{through_reflection.klass}. Try 'has_many #{reflection.name.inspect}, :through => #{through_reflection.name.inspect}, :source => <name>'. Is it one of #{source_associations.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)}?")
+    end
+  end
+
+  class HasManyThroughCantAssociateThroughHasOneOrManyReflection < ActiveRecordError #:nodoc:
+    def initialize(owner, reflection)
+      super("Cannot modify association '#{owner.class.name}##{reflection.name}' because the source reflection class '#{reflection.source_reflection.class_name}' is associated to '#{reflection.through_reflection.class_name}' via :#{reflection.source_reflection.macro}.")
+    end
+  end
+
+  class HasManyThroughCantAssociateNewRecords < ActiveRecordError #:nodoc:
+    def initialize(owner, reflection)
+      super("Cannot associate new records through '#{owner.class.name}##{reflection.name}' on '#{reflection.source_reflection.class_name rescue nil}##{reflection.source_reflection.name rescue nil}'. Both records must have an id in order to create the has_many :through record associating them.")
+    end
+  end
+
+  class HasManyThroughCantDissociateNewRecords < ActiveRecordError #:nodoc:
+    def initialize(owner, reflection)
+      super("Cannot dissociate new records through '#{owner.class.name}##{reflection.name}' on '#{reflection.source_reflection.class_name rescue nil}##{reflection.source_reflection.name rescue nil}'. Both records must have an id in order to delete the has_many :through record associating them.")
+    end
+  end
+
+  class HasManyThroughNestedAssociationsAreReadonly < ActiveRecordError #:nodoc:
+    def initialize(owner, reflection)
+      super("Cannot modify association '#{owner.class.name}##{reflection.name}' because it goes through more than one other association.")
+    end
+  end
+
+  class EagerLoadPolymorphicError < ActiveRecordError #:nodoc:
+    def initialize(reflection)
+      super("Cannot eagerly load the polymorphic association #{reflection.name.inspect}")
+    end
+  end
+
+  class ReadOnlyAssociation < ActiveRecordError #:nodoc:
+    def initialize(reflection)
+      super("Cannot add to a has_many :through association. Try adding to #{reflection.through_reflection.name.inspect}.")
+    end
+  end
+
+  # This error is raised when trying to destroy a parent instance in N:1 or 1:1 associations
+  # (has_many, has_one) when there is at least 1 child associated instance.
+  # ex: if @project.tasks.size > 0, DeleteRestrictionError will be raised when trying to destroy @project
+  class DeleteRestrictionError < ActiveRecordError #:nodoc:
+    def initialize(name)
+      super("Cannot delete record because of dependent #{name}")
+    end
+  end
+
+  # See ActiveRecord::Associations::ClassMethods for documentation.
+  module Associations # :nodoc:
+    extend ActiveSupport::Autoload
+    extend ActiveSupport::Concern
+
+    # These classes will be loaded when associations are created.
+    # So there is no need to eager load them.
+    autoload :Association,           'active_record/associations/association'
+    autoload :SingularAssociation,   'active_record/associations/singular_association'
+    autoload :CollectionAssociation, 'active_record/associations/collection_association'
+    autoload :CollectionProxy,       'active_record/associations/collection_proxy'
+
+    autoload :BelongsToAssociation,            'active_record/associations/belongs_to_association'
+    autoload :BelongsToPolymorphicAssociation, 'active_record/associations/belongs_to_polymorphic_association'
+    autoload :HasManyAssociation,              'active_record/associations/has_many_association'
+    autoload :HasManyThroughAssociation,       'active_record/associations/has_many_through_association'
+    autoload :HasOneAssociation,               'active_record/associations/has_one_association'
+    autoload :HasOneThroughAssociation,        'active_record/associations/has_one_through_association'
+    autoload :ThroughAssociation,              'active_record/associations/through_association'
+
+    module Builder #:nodoc:
+      autoload :Association,           'active_record/associations/builder/association'
+      autoload :SingularAssociation,   'active_record/associations/builder/singular_association'
+      autoload :CollectionAssociation, 'active_record/associations/builder/collection_association'
+
+      autoload :BelongsTo,           'active_record/associations/builder/belongs_to'
+      autoload :HasOne,              'active_record/associations/builder/has_one'
+      autoload :HasMany,             'active_record/associations/builder/has_many'
+      autoload :HasAndBelongsToMany, 'active_record/associations/builder/has_and_belongs_to_many'
+    end
+
+    eager_autoload do
+      autoload :Preloader,        'active_record/associations/preloader'
+      autoload :JoinDependency,   'active_record/associations/join_dependency'
+      autoload :AssociationScope, 'active_record/associations/association_scope'
+      autoload :AliasTracker,     'active_record/associations/alias_tracker'
+    end
+
+    # Clears out the association cache.
+    def clear_association_cache #:nodoc:
+      @association_cache.clear if persisted?
+    end
+
+    # :nodoc:
+    attr_reader :association_cache
+
+    # Returns the association instance for the given name, instantiating it if it doesn't already exist
+    def association(name) #:nodoc:
+      association = association_instance_get(name)
+
+      if association.nil?
+        raise AssociationNotFoundError.new(self, name) unless reflection = self.class._reflect_on_association(name)
+        association = reflection.association_class.new(self, reflection)
+        association_instance_set(name, association)
+      end
+
+      association
+    end
+
+    private
+      # Returns the specified association instance if it responds to :loaded?, nil otherwise.
+      def association_instance_get(name)
+        @association_cache[name]
+      end
+
+      # Set the specified association instance.
+      def association_instance_set(name, association)
+        @association_cache[name] = association
+      end
+
+    # \Associations are a set of macro-like class methods for tying objects together through
+    # foreign keys. They express relationships like "Project has one Project Manager"
+    # or "Project belongs to a Portfolio". Each macro adds a number of methods to the
+    # class which are specialized according to the collection or association symbol and the
+    # options hash. It works much the same way as Ruby's own <tt>attr*</tt>
+    # methods.
+    #
+    #   class Project < ActiveRecord::Base
+    #     belongs_to              :portfolio
+    #     has_one                 :project_manager
+    #     has_many                :milestones
+    #     has_and_belongs_to_many :categories
+    #   end
+    #
+    # The project class now has the following methods (and more) to ease the traversal and
+    # manipulation of its relationships:
+    # * <tt>Project#portfolio, Project#portfolio=(portfolio), Project#portfolio.nil?</tt>
+    # * <tt>Project#project_manager, Project#project_manager=(project_manager), Project#project_manager.nil?,</tt>
+    # * <tt>Project#milestones.empty?, Project#milestones.size, Project#milestones, Project#milestones<<(milestone),</tt>
+    #   <tt>Project#milestones.delete(milestone), Project#milestones.destroy(milestone), Project#milestones.find(milestone_id),</tt>
+    #   <tt>Project#milestones.build, Project#milestones.create</tt>
+    # * <tt>Project#categories.empty?, Project#categories.size, Project#categories, Project#categories<<(category1),</tt>
+    #   <tt>Project#categories.delete(category1), Project#categories.destroy(category1)</tt>
+    #
+    # === A word of warning
+    #
+    # Don't create associations that have the same name as instance methods of
+    # <tt>ActiveRecord::Base</tt>. Since the association adds a method with that name to
+    # its model, it will override the inherited method and break things.
+    # For instance, +attributes+ and +connection+ would be bad choices for association names.
+    #
+    # == Auto-generated methods
+    # See also Instance Public methods below for more details.
+    #
+    # === Singular associations (one-to-one)
+    #                                     |            |  belongs_to  |
+    #   generated methods                 | belongs_to | :polymorphic | has_one
+    #   ----------------------------------+------------+--------------+---------
+    #   other(force_reload=false)         |     X      |      X       |    X
+    #   other=(other)                     |     X      |      X       |    X
+    #   build_other(attributes={})        |     X      |              |    X
+    #   create_other(attributes={})       |     X      |              |    X
+    #   create_other!(attributes={})      |     X      |              |    X
+    #
+    # ===Collection associations (one-to-many / many-to-many)
+    #                                     |       |          | has_many
+    #   generated methods                 | habtm | has_many | :through
+    #   ----------------------------------+-------+----------+----------
+    #   others(force_reload=false)        |   X   |    X     |    X
+    #   others=(other,other,...)          |   X   |    X     |    X
+    #   other_ids                         |   X   |    X     |    X
+    #   other_ids=(id,id,...)             |   X   |    X     |    X
+    #   others<<                          |   X   |    X     |    X
+    #   others.push                       |   X   |    X     |    X
+    #   others.concat                     |   X   |    X     |    X
+    #   others.build(attributes={})       |   X   |    X     |    X
+    #   others.create(attributes={})      |   X   |    X     |    X
+    #   others.create!(attributes={})     |   X   |    X     |    X
+    #   others.size                       |   X   |    X     |    X
+    #   others.length                     |   X   |    X     |    X
+    #   others.count                      |   X   |    X     |    X
+    #   others.sum(*args)                 |   X   |    X     |    X
+    #   others.empty?                     |   X   |    X     |    X
+    #   others.clear                      |   X   |    X     |    X
+    #   others.delete(other,other,...)    |   X   |    X     |    X
+    #   others.delete_all                 |   X   |    X     |    X
+    #   others.destroy(other,other,...)   |   X   |    X     |    X
+    #   others.destroy_all                |   X   |    X     |    X
+    #   others.find(*args)                |   X   |    X     |    X
+    #   others.exists?                    |   X   |    X     |    X
+    #   others.distinct                   |   X   |    X     |    X
+    #   others.uniq                       |   X   |    X     |    X
+    #   others.reset                      |   X   |    X     |    X
+    #
+    # === Overriding generated methods
+    #
+    # Association methods are generated in a module that is included into the model class,
+    # which allows you to easily override with your own methods and call the original
+    # generated method with +super+. For example:
+    #
+    #   class Car < ActiveRecord::Base
+    #     belongs_to :owner
+    #     belongs_to :old_owner
+    #     def owner=(new_owner)
+    #       self.old_owner = self.owner
+    #       super
+    #     end
+    #   end
+    #
+    # If your model class is <tt>Project</tt>, the module is
+    # named <tt>Project::GeneratedFeatureMethods</tt>. The GeneratedFeatureMethods module is
+    # included in the model class immediately after the (anonymous) generated attributes methods
+    # module, meaning an association will override the methods for an attribute with the same name.
+    #
+    # == Cardinality and associations
+    #
+    # Active Record associations can be used to describe one-to-one, one-to-many and many-to-many
+    # relationships between models. Each model uses an association to describe its role in
+    # the relation. The +belongs_to+ association is always used in the model that has
+    # the foreign key.
+    #
+    # === One-to-one
+    #
+    # Use +has_one+ in the base, and +belongs_to+ in the associated model.
+    #
+    #   class Employee < ActiveRecord::Base
+    #     has_one :office
+    #   end
+    #   class Office < ActiveRecord::Base
+    #     belongs_to :employee    # foreign key - employee_id
+    #   end
+    #
+    # === One-to-many
+    #
+    # Use +has_many+ in the base, and +belongs_to+ in the associated model.
+    #
+    #   class Manager < ActiveRecord::Base
+    #     has_many :employees
+    #   end
+    #   class Employee < ActiveRecord::Base
+    #     belongs_to :manager     # foreign key - manager_id
+    #   end
+    #
+    # === Many-to-many
+    #
+    # There are two ways to build a many-to-many relationship.
+    #
+    # The first way uses a +has_many+ association with the <tt>:through</tt> option and a join model, so
+    # there are two stages of associations.
+    #
+    #   class Assignment < ActiveRecord::Base
+    #     belongs_to :programmer  # foreign key - programmer_id
+    #     belongs_to :project     # foreign key - project_id
+    #   end
+    #   class Programmer < ActiveRecord::Base
+    #     has_many :assignments
+    #     has_many :projects, through: :assignments
+    #   end
+    #   class Project < ActiveRecord::Base
+    #     has_many :assignments
+    #     has_many :programmers, through: :assignments
+    #   end
+    #
+    # For the second way, use +has_and_belongs_to_many+ in both models. This requires a join table
+    # that has no corresponding model or primary key.
+    #
+    #   class Programmer < ActiveRecord::Base
+    #     has_and_belongs_to_many :projects       # foreign keys in the join table
+    #   end
+    #   class Project < ActiveRecord::Base
+    #     has_and_belongs_to_many :programmers    # foreign keys in the join table
+    #   end
+    #
+    # Choosing which way to build a many-to-many relationship is not always simple.
+    # If you need to work with the relationship model as its own entity,
+    # use <tt>has_many :through</tt>. Use +has_and_belongs_to_many+ when working with legacy schemas or when
+    # you never work directly with the relationship itself.
+    #
+    # == Is it a +belongs_to+ or +has_one+ association?
+    #
+    # Both express a 1-1 relationship. The difference is mostly where to place the foreign
+    # key, which goes on the table for the class declaring the +belongs_to+ relationship.
+    #
+    #   class User < ActiveRecord::Base
+    #     # I reference an account.
+    #     belongs_to :account
+    #   end
+    #
+    #   class Account < ActiveRecord::Base
+    #     # One user references me.
+    #     has_one :user
+    #   end
+    #
+    # The tables for these classes could look something like:
+    #
+    #   CREATE TABLE users (
+    #     id int(11) NOT NULL auto_increment,
+    #     account_id int(11) default NULL,
+    #     name varchar default NULL,
+    #     PRIMARY KEY  (id)
+    #   )
+    #
+    #   CREATE TABLE accounts (
+    #     id int(11) NOT NULL auto_increment,
+    #     name varchar default NULL,
+    #     PRIMARY KEY  (id)
+    #   )
+    #
+    # == Unsaved objects and associations
+    #
+    # You can manipulate objects and associations before they are saved to the database, but
+    # there is some special behavior you should be aware of, mostly involving the saving of
+    # associated objects.
+    #
+    # You can set the <tt>:autosave</tt> option on a <tt>has_one</tt>, <tt>belongs_to</tt>,
+    # <tt>has_many</tt>, or <tt>has_and_belongs_to_many</tt> association. Setting it
+    # to +true+ will _always_ save the members, whereas setting it to +false+ will
+    # _never_ save the members. More details about <tt>:autosave</tt> option is available at
+    # AutosaveAssociation.
+    #
+    # === One-to-one associations
+    #
+    # * Assigning an object to a +has_one+ association automatically saves that object and
+    #   the object being replaced (if there is one), in order to update their foreign
+    #   keys - except if the parent object is unsaved (<tt>new_record? == true</tt>).
+    # * If either of these saves fail (due to one of the objects being invalid), an
+    #   <tt>ActiveRecord::RecordNotSaved</tt> exception is raised and the assignment is
+    #   cancelled.
+    # * If you wish to assign an object to a +has_one+ association without saving it,
+    #   use the <tt>build_association</tt> method (documented below). The object being
+    #   replaced will still be saved to update its foreign key.
+    # * Assigning an object to a +belongs_to+ association does not save the object, since
+    #   the foreign key field belongs on the parent. It does not save the parent either.
+    #
+    # === Collections
+    #
+    # * Adding an object to a collection (+has_many+ or +has_and_belongs_to_many+) automatically
+    #   saves that object, except if the parent object (the owner of the collection) is not yet
+    #   stored in the database.
+    # * If saving any of the objects being added to a collection (via <tt>push</tt> or similar)
+    #   fails, then <tt>push</tt> returns +false+.
+    # * If saving fails while replacing the collection (via <tt>association=</tt>), an
+    #   <tt>ActiveRecord::RecordNotSaved</tt> exception is raised and the assignment is
+    #   cancelled.
+    # * You can add an object to a collection without automatically saving it by using the
+    #   <tt>collection.build</tt> method (documented below).
+    # * All unsaved (<tt>new_record? == true</tt>) members of the collection are automatically
+    #   saved when the parent is saved.
+    #
+    # == Customizing the query
+    #
+    # \Associations are built from <tt>Relation</tt>s, and you can use the <tt>Relation</tt> syntax
+    # to customize them. For example, to add a condition:
+    #
+    #   class Blog < ActiveRecord::Base
+    #     has_many :published_posts, -> { where published: true }, class_name: 'Post'
+    #   end
+    #
+    # Inside the <tt>-> { ... }</tt> block you can use all of the usual <tt>Relation</tt> methods.
+    #
+    # === Accessing the owner object
+    #
+    # Sometimes it is useful to have access to the owner object when building the query. The owner
+    # is passed as a parameter to the block. For example, the following association would find all
+    # events that occur on the user's birthday:
+    #
+    #   class User < ActiveRecord::Base
+    #     has_many :birthday_events, ->(user) { where starts_on: user.birthday }, class_name: 'Event'
+    #   end
+    #
+    # Note: Joining, eager loading and preloading of these associations is not fully possible.
+    # These operations happen before instance creation and the scope will be called with a +nil+ argument.
+    # This can lead to unexpected behavior and is deprecated.
+    #
+    # == Association callbacks
+    #
+    # Similar to the normal callbacks that hook into the life cycle of an Active Record object,
+    # you can also define callbacks that get triggered when you add an object to or remove an
+    # object from an association collection.
+    #
+    #   class Project
+    #     has_and_belongs_to_many :developers, after_add: :evaluate_velocity
+    #
+    #     def evaluate_velocity(developer)
+    #       ...
+    #     end
+    #   end
+    #
+    # It's possible to stack callbacks by passing them as an array. Example:
+    #
+    #   class Project
+    #     has_and_belongs_to_many :developers,
+    #                             after_add: [:evaluate_velocity, Proc.new { |p, d| p.shipping_date = Time.now}]
+    #   end
+    #
+    # Possible callbacks are: +before_add+, +after_add+, +before_remove+ and +after_remove+.
+    #
+    # Should any of the +before_add+ callbacks throw an exception, the object does not get
+    # added to the collection. Same with the +before_remove+ callbacks; if an exception is
+    # thrown the object doesn't get removed.
+    #
+    # == Association extensions
+    #
+    # The proxy objects that control the access to associations can be extended through anonymous
+    # modules. This is especially beneficial for adding new finders, creators, and other
+    # factory-type methods that are only used as part of this association.
+    #
+    #   class Account < ActiveRecord::Base
+    #     has_many :people do
+    #       def find_or_create_by_name(name)
+    #         first_name, last_name = name.split(" ", 2)
+    #         find_or_create_by(first_name: first_name, last_name: last_name)
+    #       end
+    #     end
+    #   end
+    #
+    #   person = Account.first.people.find_or_create_by_name("David Heinemeier Hansson")
+    #   person.first_name # => "David"
+    #   person.last_name  # => "Heinemeier Hansson"
+    #
+    # If you need to share the same extensions between many associations, you can use a named
+    # extension module.
+    #
+    #   module FindOrCreateByNameExtension
+    #     def find_or_create_by_name(name)
+    #       first_name, last_name = name.split(" ", 2)
+    #       find_or_create_by(first_name: first_name, last_name: last_name)
+    #     end
+    #   end
+    #
+    #   class Account < ActiveRecord::Base
+    #     has_many :people, -> { extending FindOrCreateByNameExtension }
+    #   end
+    #
+    #   class Company < ActiveRecord::Base
+    #     has_many :people, -> { extending FindOrCreateByNameExtension }
+    #   end
+    #
+    # Some extensions can only be made to work with knowledge of the association's internals.
+    # Extensions can access relevant state using the following methods (where +items+ is the
+    # name of the association):
+    #
+    # * <tt>record.association(:items).owner</tt> - Returns the object the association is part of.
+    # * <tt>record.association(:items).reflection</tt> - Returns the reflection object that describes the association.
+    # * <tt>record.association(:items).target</tt> - Returns the associated object for +belongs_to+ and +has_one+, or
+    #   the collection of associated objects for +has_many+ and +has_and_belongs_to_many+.
+    #
+    # However, inside the actual extension code, you will not have access to the <tt>record</tt> as
+    # above. In this case, you can access <tt>proxy_association</tt>. For example,
+    # <tt>record.association(:items)</tt> and <tt>record.items.proxy_association</tt> will return
+    # the same object, allowing you to make calls like <tt>proxy_association.owner</tt> inside
+    # association extensions.
+    #
+    # == Association Join Models
+    #
+    # Has Many associations can be configured with the <tt>:through</tt> option to use an
+    # explicit join model to retrieve the data. This operates similarly to a
+    # +has_and_belongs_to_many+ association. The advantage is that you're able to add validations,
+    # callbacks, and extra attributes on the join model. Consider the following schema:
+    #
+    #   class Author < ActiveRecord::Base
+    #     has_many :authorships
+    #     has_many :books, through: :authorships
+    #   end
+    #
+    #   class Authorship < ActiveRecord::Base
+    #     belongs_to :author
+    #     belongs_to :book
+    #   end
+    #
+    #   @author = Author.first
+    #   @author.authorships.collect { |a| a.book } # selects all books that the author's authorships belong to
+    #   @author.books                              # selects all books by using the Authorship join model
+    #
+    # You can also go through a +has_many+ association on the join model:
+    #
+    #   class Firm < ActiveRecord::Base
+    #     has_many   :clients
+    #     has_many   :invoices, through: :clients
+    #   end
+    #
+    #   class Client < ActiveRecord::Base
+    #     belongs_to :firm
+    #     has_many   :invoices
+    #   end
+    #
+    #   class Invoice < ActiveRecord::Base
+    #     belongs_to :client
+    #   end
+    #
+    #   @firm = Firm.first
+    #   @firm.clients.flat_map { |c| c.invoices } # select all invoices for all clients of the firm
+    #   @firm.invoices                            # selects all invoices by going through the Client join model
+    #
+    # Similarly you can go through a +has_one+ association on the join model:
+    #
+    #   class Group < ActiveRecord::Base
+    #     has_many   :users
+    #     has_many   :avatars, through: :users
+    #   end
+    #
+    #   class User < ActiveRecord::Base
+    #     belongs_to :group
+    #     has_one    :avatar
+    #   end
+    #
+    #   class Avatar < ActiveRecord::Base
+    #     belongs_to :user
+    #   end
+    #
+    #   @group = Group.first
+    #   @group.users.collect { |u| u.avatar }.compact # select all avatars for all users in the group
+    #   @group.avatars                                # selects all avatars by going through the User join model.
+    #
+    # An important caveat with going through +has_one+ or +has_many+ associations on the
+    # join model is that these associations are *read-only*. For example, the following
+    # would not work following the previous example:
+    #
+    #   @group.avatars << Avatar.new   # this would work if User belonged_to Avatar rather than the other way around
+    #   @group.avatars.delete(@group.avatars.last)  # so would this
+    #
+    # == Setting Inverses
+    #
+    # If you are using a +belongs_to+ on the join model, it is a good idea to set the
+    # <tt>:inverse_of</tt> option on the +belongs_to+, which will mean that the following example
+    # works correctly (where <tt>tags</tt> is a +has_many+ <tt>:through</tt> association):
+    #
+    #   @post = Post.first
+    #   @tag = @post.tags.build name: "ruby"
+    #   @tag.save
+    #
+    # The last line ought to save the through record (a <tt>Taggable</tt>). This will only work if the
+    # <tt>:inverse_of</tt> is set:
+    #
+    #   class Taggable < ActiveRecord::Base
+    #     belongs_to :post
+    #     belongs_to :tag, inverse_of: :taggings
+    #   end
+    #
+    # If you do not set the <tt>:inverse_of</tt> record, the association will
+    # do its best to match itself up with the correct inverse. Automatic
+    # inverse detection only works on <tt>has_many</tt>, <tt>has_one</tt>, and
+    # <tt>belongs_to</tt> associations.
+    #
+    # Extra options on the associations, as defined in the
+    # <tt>AssociationReflection::INVALID_AUTOMATIC_INVERSE_OPTIONS</tt> constant, will
+    # also prevent the association's inverse from being found automatically.
+    #
+    # The automatic guessing of the inverse association uses a heuristic based
+    # on the name of the class, so it may not work for all associations,
+    # especially the ones with non-standard names.
+    #
+    # You can turn off the automatic detection of inverse associations by setting
+    # the <tt>:inverse_of</tt> option to <tt>false</tt> like so:
+    #
+    #   class Taggable < ActiveRecord::Base
+    #     belongs_to :tag, inverse_of: false
+    #   end
+    #
+    # == Nested \Associations
+    #
+    # You can actually specify *any* association with the <tt>:through</tt> option, including an
+    # association which has a <tt>:through</tt> option itself. For example:
+    #
+    #   class Author < ActiveRecord::Base
+    #     has_many :posts
+    #     has_many :comments, through: :posts
+    #     has_many :commenters, through: :comments
+    #   end
+    #
+    #   class Post < ActiveRecord::Base
+    #     has_many :comments
+    #   end
+    #
+    #   class Comment < ActiveRecord::Base
+    #     belongs_to :commenter
+    #   end
+    #
+    #   @author = Author.first
+    #   @author.commenters # => People who commented on posts written by the author
+    #
+    # An equivalent way of setting up this association this would be:
+    #
+    #   class Author < ActiveRecord::Base
+    #     has_many :posts
+    #     has_many :commenters, through: :posts
+    #   end
+    #
+    #   class Post < ActiveRecord::Base
+    #     has_many :comments
+    #     has_many :commenters, through: :comments
+    #   end
+    #
+    #   class Comment < ActiveRecord::Base
+    #     belongs_to :commenter
+    #   end
+    #
+    # When using nested association, you will not be able to modify the association because there
+    # is not enough information to know what modification to make. For example, if you tried to
+    # add a <tt>Commenter</tt> in the example above, there would be no way to tell how to set up the
+    # intermediate <tt>Post</tt> and <tt>Comment</tt> objects.
+    #
+    # == Polymorphic \Associations
+    #
+    # Polymorphic associations on models are not restricted on what types of models they
+    # can be associated with. Rather, they specify an interface that a +has_many+ association
+    # must adhere to.
+    #
+    #   class Asset < ActiveRecord::Base
+    #     belongs_to :attachable, polymorphic: true
+    #   end
+    #
+    #   class Post < ActiveRecord::Base
+    #     has_many :assets, as: :attachable         # The :as option specifies the polymorphic interface to use.
+    #   end
+    #
+    #   @asset.attachable = @post
+    #
+    # This works by using a type column in addition to a foreign key to specify the associated
+    # record. In the Asset example, you'd need an +attachable_id+ integer column and an
+    # +attachable_type+ string column.
+    #
+    # Using polymorphic associations in combination with single table inheritance (STI) is
+    # a little tricky. In order for the associations to work as expected, ensure that you
+    # store the base model for the STI models in the type column of the polymorphic
+    # association. To continue with the asset example above, suppose there are guest posts
+    # and member posts that use the posts table for STI. In this case, there must be a +type+
+    # column in the posts table.
+    #
+    # Note: The <tt>attachable_type=</tt> method is being called when assigning an +attachable+.
+    # The +class_name+ of the +attachable+ is passed as a String.
+    #
+    #   class Asset < ActiveRecord::Base
+    #     belongs_to :attachable, polymorphic: true
+    #
+    #     def attachable_type=(class_name)
+    #        super(class_name.constantize.base_class.to_s)
+    #     end
+    #   end
+    #
+    #   class Post < ActiveRecord::Base
+    #     # because we store "Post" in attachable_type now dependent: :destroy will work
+    #     has_many :assets, as: :attachable, dependent: :destroy
+    #   end
+    #
+    #   class GuestPost < Post
+    #   end
+    #
+    #   class MemberPost < Post
+    #   end
+    #
+    # == Caching
+    #
+    # All of the methods are built on a simple caching principle that will keep the result
+    # of the last query around unless specifically instructed not to. The cache is even
+    # shared across methods to make it even cheaper to use the macro-added methods without
+    # worrying too much about performance at the first go.
+    #
+    #   project.milestones             # fetches milestones from the database
+    #   project.milestones.size        # uses the milestone cache
+    #   project.milestones.empty?      # uses the milestone cache
+    #   project.milestones(true).size  # fetches milestones from the database
+    #   project.milestones             # uses the milestone cache
+    #
+    # == Eager loading of associations
+    #
+    # Eager loading is a way to find objects of a certain class and a number of named associations.
+    # This is one of the easiest ways of to prevent the dreaded N+1 problem in which fetching 100
+    # posts that each need to display their author triggers 101 database queries. Through the
+    # use of eager loading, the number of queries will be reduced from 101 to 2.
+    #
+    #   class Post < ActiveRecord::Base
+    #     belongs_to :author
+    #     has_many   :comments
+    #   end
+    #
+    # Consider the following loop using the class above:
+    #
+    #   Post.all.each do |post|
+    #     puts "Post:            " + post.title
+    #     puts "Written by:      " + post.author.name
+    #     puts "Last comment on: " + post.comments.first.created_on
+    #   end
+    #
+    # To iterate over these one hundred posts, we'll generate 201 database queries. Let's
+    # first just optimize it for retrieving the author:
+    #
+    #   Post.includes(:author).each do |post|
+    #
+    # This references the name of the +belongs_to+ association that also used the <tt>:author</tt>
+    # symbol. After loading the posts, find will collect the +author_id+ from each one and load
+    # all the referenced authors with one query. Doing so will cut down the number of queries
+    # from 201 to 102.
+    #
+    # We can improve upon the situation further by referencing both associations in the finder with:
+    #
+    #   Post.includes(:author, :comments).each do |post|
+    #
+    # This will load all comments with a single query. This reduces the total number of queries
+    # to 3. More generally the number of queries will be 1 plus the number of associations
+    # named (except if some of the associations are polymorphic +belongs_to+ - see below).
+    #
+    # To include a deep hierarchy of associations, use a hash:
+    #
+    #   Post.includes(:author, {comments: {author: :gravatar}}).each do |post|
+    #
+    # That'll grab not only all the comments but all their authors and gravatar pictures.
+    # You can mix and match symbols, arrays and hashes in any combination to describe the
+    # associations you want to load.
+    #
+    # All of this power shouldn't fool you into thinking that you can pull out huge amounts
+    # of data with no performance penalty just because you've reduced the number of queries.
+    # The database still needs to send all the data to Active Record and it still needs to
+    # be processed. So it's no catch-all for performance problems, but it's a great way to
+    # cut down on the number of queries in a situation as the one described above.
+    #
+    # Since only one table is loaded at a time, conditions or orders cannot reference tables
+    # other than the main one. If this is the case Active Record falls back to the previously
+    # used LEFT OUTER JOIN based strategy. For example
+    #
+    #   Post.includes([:author, :comments]).where(['comments.approved = ?', true])
+    #
+    # This will result in a single SQL query with joins along the lines of:
+    # <tt>LEFT OUTER JOIN comments ON comments.post_id = posts.id</tt> and
+    # <tt>LEFT OUTER JOIN authors ON authors.id = posts.author_id</tt>. Note that using conditions
+    # like this can have unintended consequences.
+    # In the above example posts with no approved comments are not returned at all, because
+    # the conditions apply to the SQL statement as a whole and not just to the association.
+    #
+    # You must disambiguate column references for this fallback to happen, for example
+    # <tt>order: "author.name DESC"</tt> will work but <tt>order: "name DESC"</tt> will not.
+    #
+    # If you want to load all posts (including posts with no approved comments) then write
+    # your own LEFT OUTER JOIN query using ON
+    #
+    #   Post.joins("LEFT OUTER JOIN comments ON comments.post_id = posts.id AND comments.approved = '1'")
+    #
+    # In this case it is usually more natural to include an association which has conditions defined on it:
+    #
+    #   class Post < ActiveRecord::Base
+    #     has_many :approved_comments, -> { where approved: true }, class_name: 'Comment'
+    #   end
+    #
+    #   Post.includes(:approved_comments)
+    #
+    # This will load posts and eager load the +approved_comments+ association, which contains
+    # only those comments that have been approved.
+    #
+    # If you eager load an association with a specified <tt>:limit</tt> option, it will be ignored,
+    # returning all the associated objects:
+    #
+    #   class Picture < ActiveRecord::Base
+    #     has_many :most_recent_comments, -> { order('id DESC').limit(10) }, class_name: 'Comment'
+    #   end
+    #
+    #   Picture.includes(:most_recent_comments).first.most_recent_comments # => returns all associated comments.
+    #
+    # Eager loading is supported with polymorphic associations.
+    #
+    #   class Address < ActiveRecord::Base
+    #     belongs_to :addressable, polymorphic: true
+    #   end
+    #
+    # A call that tries to eager load the addressable model
+    #
+    #   Address.includes(:addressable)
+    #
+    # This will execute one query to load the addresses and load the addressables with one
+    # query per addressable type.
+    # For example if all the addressables are either of class Person or Company then a total
+    # of 3 queries will be executed. The list of addressable types to load is determined on
+    # the back of the addresses loaded. This is not supported if Active Record has to fallback
+    # to the previous implementation of eager loading and will raise <tt>ActiveRecord::EagerLoadPolymorphicError</tt>.
+    # The reason is that the parent model's type is a column value so its corresponding table
+    # name cannot be put in the +FROM+/+JOIN+ clauses of that query.
+    #
+    # == Table Aliasing
+    #
+    # Active Record uses table aliasing in the case that a table is referenced multiple times
+    # in a join. If a table is referenced only once, the standard table name is used. The
+    # second time, the table is aliased as <tt>#{reflection_name}_#{parent_table_name}</tt>.
+    # Indexes are appended for any more successive uses of the table name.
+    #
+    #   Post.joins(:comments)
+    #   # => SELECT ... FROM posts INNER JOIN comments ON ...
+    #   Post.joins(:special_comments) # STI
+    #   # => SELECT ... FROM posts INNER JOIN comments ON ... AND comments.type = 'SpecialComment'
+    #   Post.joins(:comments, :special_comments) # special_comments is the reflection name, posts is the parent table name
+    #   # => SELECT ... FROM posts INNER JOIN comments ON ... INNER JOIN comments special_comments_posts
+    #
+    # Acts as tree example:
+    #
+    #   TreeMixin.joins(:children)
+    #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
+    #   TreeMixin.joins(children: :parent)
+    #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
+    #                               INNER JOIN parents_mixins ...
+    #   TreeMixin.joins(children: {parent: :children})
+    #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
+    #                               INNER JOIN parents_mixins ...
+    #                               INNER JOIN mixins childrens_mixins_2
+    #
+    # Has and Belongs to Many join tables use the same idea, but add a <tt>_join</tt> suffix:
+    #
+    #   Post.joins(:categories)
+    #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
+    #   Post.joins(categories: :posts)
+    #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
+    #                              INNER JOIN categories_posts posts_categories_join INNER JOIN posts posts_categories
+    #   Post.joins(categories: {posts: :categories})
+    #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
+    #                              INNER JOIN categories_posts posts_categories_join INNER JOIN posts posts_categories
+    #                              INNER JOIN categories_posts categories_posts_join INNER JOIN categories categories_posts_2
+    #
+    # If you wish to specify your own custom joins using <tt>joins</tt> method, those table
+    # names will take precedence over the eager associations:
+    #
+    #   Post.joins(:comments).joins("inner join comments ...")
+    #   # => SELECT ... FROM posts INNER JOIN comments_posts ON ... INNER JOIN comments ...
+    #   Post.joins(:comments, :special_comments).joins("inner join comments ...")
+    #   # => SELECT ... FROM posts INNER JOIN comments comments_posts ON ...
+    #                              INNER JOIN comments special_comments_posts ...
+    #                              INNER JOIN comments ...
+    #
+    # Table aliases are automatically truncated according to the maximum length of table identifiers
+    # according to the specific database.
+    #
+    # == Modules
+    #
+    # By default, associations will look for objects within the current module scope. Consider:
+    #
+    #   module MyApplication
+    #     module Business
+    #       class Firm < ActiveRecord::Base
+    #         has_many :clients
+    #       end
+    #
+    #       class Client < ActiveRecord::Base; end
+    #     end
+    #   end
+    #
+    # When <tt>Firm#clients</tt> is called, it will in turn call
+    # <tt>MyApplication::Business::Client.find_all_by_firm_id(firm.id)</tt>.
+    # If you want to associate with a class in another module scope, this can be done by
+    # specifying the complete class name.
+    #
+    #   module MyApplication
+    #     module Business
+    #       class Firm < ActiveRecord::Base; end
+    #     end
+    #
+    #     module Billing
+    #       class Account < ActiveRecord::Base
+    #         belongs_to :firm, class_name: "MyApplication::Business::Firm"
+    #       end
+    #     end
+    #   end
+    #
+    # == Bi-directional associations
+    #
+    # When you specify an association there is usually an association on the associated model
+    # that specifies the same relationship in reverse. For example, with the following models:
+    #
+    #    class Dungeon < ActiveRecord::Base
+    #      has_many :traps
+    #      has_one :evil_wizard
+    #    end
+    #
+    #    class Trap < ActiveRecord::Base
+    #      belongs_to :dungeon
+    #    end
+    #
+    #    class EvilWizard < ActiveRecord::Base
+    #      belongs_to :dungeon
+    #    end
+    #
+    # The +traps+ association on +Dungeon+ and the +dungeon+ association on +Trap+ are
+    # the inverse of each other and the inverse of the +dungeon+ association on +EvilWizard+
+    # is the +evil_wizard+ association on +Dungeon+ (and vice-versa). By default,
+    # Active Record doesn't know anything about these inverse relationships and so no object
+    # loading optimization is possible. For example:
+    #
+    #    d = Dungeon.first
+    #    t = d.traps.first
+    #    d.level == t.dungeon.level # => true
+    #    d.level = 10
+    #    d.level == t.dungeon.level # => false
+    #
+    # The +Dungeon+ instances +d+ and <tt>t.dungeon</tt> in the above example refer to
+    # the same object data from the database, but are actually different in-memory copies
+    # of that data. Specifying the <tt>:inverse_of</tt> option on associations lets you tell
+    # Active Record about inverse relationships and it will optimise object loading. For
+    # example, if we changed our model definitions to:
+    #
+    #    class Dungeon < ActiveRecord::Base
+    #      has_many :traps, inverse_of: :dungeon
+    #      has_one :evil_wizard, inverse_of: :dungeon
+    #    end
+    #
+    #    class Trap < ActiveRecord::Base
+    #      belongs_to :dungeon, inverse_of: :traps
+    #    end
+    #
+    #    class EvilWizard < ActiveRecord::Base
+    #      belongs_to :dungeon, inverse_of: :evil_wizard
+    #    end
+    #
+    # Then, from our code snippet above, +d+ and <tt>t.dungeon</tt> are actually the same
+    # in-memory instance and our final <tt>d.level == t.dungeon.level</tt> will return +true+.
+    #
+    # There are limitations to <tt>:inverse_of</tt> support:
+    #
+    # * does not work with <tt>:through</tt> associations.
+    # * does not work with <tt>:polymorphic</tt> associations.
+    # * for +belongs_to+ associations +has_many+ inverse associations are ignored.
+    #
+    # == Deleting from associations
+    #
+    # === Dependent associations
+    #
+    # +has_many+, +has_one+ and +belongs_to+ associations support the <tt>:dependent</tt> option.
+    # This allows you to specify that associated records should be deleted when the owner is
+    # deleted.
+    #
+    # For example:
+    #
+    #     class Author
+    #       has_many :posts, dependent: :destroy
+    #     end
+    #     Author.find(1).destroy # => Will destroy all of the author's posts, too
+    #
+    # The <tt>:dependent</tt> option can have different values which specify how the deletion
+    # is done. For more information, see the documentation for this option on the different
+    # specific association types. When no option is given, the behavior is to do nothing
+    # with the associated records when destroying a record.
+    #
+    # Note that <tt>:dependent</tt> is implemented using Rails' callback
+    # system, which works by processing callbacks in order. Therefore, other
+    # callbacks declared either before or after the <tt>:dependent</tt> option
+    # can affect what it does.
+    #
+    # === Delete or destroy?
+    #
+    # +has_many+ and +has_and_belongs_to_many+ associations have the methods <tt>destroy</tt>,
+    # <tt>delete</tt>, <tt>destroy_all</tt> and <tt>delete_all</tt>.
+    #
+    # For +has_and_belongs_to_many+, <tt>delete</tt> and <tt>destroy</tt> are the same: they
+    # cause the records in the join table to be removed.
+    #
+    # For +has_many+, <tt>destroy</tt> and <tt>destroy_all</tt> will always call the <tt>destroy</tt> method of the
+    # record(s) being removed so that callbacks are run. However <tt>delete</tt> and <tt>delete_all</tt> will either
+    # do the deletion according to the strategy specified by the <tt>:dependent</tt> option, or
+    # if no <tt>:dependent</tt> option is given, then it will follow the default strategy.
+    # The default strategy is <tt>:nullify</tt> (set the foreign keys to <tt>nil</tt>), except for
+    # +has_many+ <tt>:through</tt>, where the default strategy is <tt>delete_all</tt> (delete
+    # the join records, without running their callbacks).
+    #
+    # There is also a <tt>clear</tt> method which is the same as <tt>delete_all</tt>, except that
+    # it returns the association rather than the records which have been deleted.
+    #
+    # === What gets deleted?
+    #
+    # There is a potential pitfall here: +has_and_belongs_to_many+ and +has_many+ <tt>:through</tt>
+    # associations have records in join tables, as well as the associated records. So when we
+    # call one of these deletion methods, what exactly should be deleted?
+    #
+    # The answer is that it is assumed that deletion on an association is about removing the
+    # <i>link</i> between the owner and the associated object(s), rather than necessarily the
+    # associated objects themselves. So with +has_and_belongs_to_many+ and +has_many+
+    # <tt>:through</tt>, the join records will be deleted, but the associated records won't.
+    #
+    # This makes sense if you think about it: if you were to call <tt>post.tags.delete(Tag.find_by(name: 'food'))</tt>
+    # you would want the 'food' tag to be unlinked from the post, rather than for the tag itself
+    # to be removed from the database.
+    #
+    # However, there are examples where this strategy doesn't make sense. For example, suppose
+    # a person has many projects, and each project has many tasks. If we deleted one of a person's
+    # tasks, we would probably not want the project to be deleted. In this scenario, the delete method
+    # won't actually work: it can only be used if the association on the join model is a
+    # +belongs_to+. In other situations you are expected to perform operations directly on
+    # either the associated records or the <tt>:through</tt> association.
+    #
+    # With a regular +has_many+ there is no distinction between the "associated records"
+    # and the "link", so there is only one choice for what gets deleted.
+    #
+    # With +has_and_belongs_to_many+ and +has_many+ <tt>:through</tt>, if you want to delete the
+    # associated records themselves, you can always do something along the lines of
+    # <tt>person.tasks.each(&:destroy)</tt>.
+    #
+    # == Type safety with <tt>ActiveRecord::AssociationTypeMismatch</tt>
+    #
+    # If you attempt to assign an object to an association that doesn't match the inferred
+    # or specified <tt>:class_name</tt>, you'll get an <tt>ActiveRecord::AssociationTypeMismatch</tt>.
+    #
+    # == Options
+    #
+    # All of the association macros can be specialized through options. This makes cases
+    # more complex than the simple and guessable ones possible.
+    module ClassMethods
+      # Specifies a one-to-many association. The following methods for retrieval and query of
+      # collections of associated objects will be added:
+      #
+      # +collection+ is a placeholder for the symbol passed as the +name+ argument, so
+      # <tt>has_many :clients</tt> would add among others <tt>clients.empty?</tt>.
+      #
+      # [collection(force_reload = false)]
+      #   Returns an array of all the associated objects.
+      #   An empty array is returned if none are found.
+      # [collection<<(object, ...)]
+      #   Adds one or more objects to the collection by setting their foreign keys to the collection's primary key.
+      #   Note that this operation instantly fires update SQL without waiting for the save or update call on the
+      #   parent object, unless the parent object is a new record.
+      # [collection.delete(object, ...)]
+      #   Removes one or more objects from the collection by setting their foreign keys to +NULL+.
+      #   Objects will be in addition destroyed if they're associated with <tt>dependent: :destroy</tt>,
+      #   and deleted if they're associated with <tt>dependent: :delete_all</tt>.
+      #
+      #   If the <tt>:through</tt> option is used, then the join records are deleted (rather than
+      #   nullified) by default, but you can specify <tt>dependent: :destroy</tt> or
+      #   <tt>dependent: :nullify</tt> to override this.
+      # [collection.destroy(object, ...)]
+      #   Removes one or more objects from the collection by running <tt>destroy</tt> on
+      #   each record, regardless of any dependent option, ensuring callbacks are run.
+      #
+      #   If the <tt>:through</tt> option is used, then the join records are destroyed
+      #   instead, not the objects themselves.
+      # [collection=objects]
+      #   Replaces the collections content by deleting and adding objects as appropriate. If the <tt>:through</tt>
+      #   option is true callbacks in the join models are triggered except destroy callbacks, since deletion is
+      #   direct.
+      # [collection_singular_ids]
+      #   Returns an array of the associated objects' ids
+      # [collection_singular_ids=ids]
+      #   Replace the collection with the objects identified by the primary keys in +ids+. This
+      #   method loads the models and calls <tt>collection=</tt>. See above.
+      # [collection.clear]
+      #   Removes every object from the collection. This destroys the associated objects if they
+      #   are associated with <tt>dependent: :destroy</tt>, deletes them directly from the
+      #   database if <tt>dependent: :delete_all</tt>, otherwise sets their foreign keys to +NULL+.
+      #   If the <tt>:through</tt> option is true no destroy callbacks are invoked on the join models.
+      #   Join models are directly deleted.
+      # [collection.empty?]
+      #   Returns +true+ if there are no associated objects.
+      # [collection.size]
+      #   Returns the number of associated objects.
+      # [collection.find(...)]
+      #   Finds an associated object according to the same rules as <tt>ActiveRecord::Base.find</tt>.
+      # [collection.exists?(...)]
+      #   Checks whether an associated object with the given conditions exists.
+      #   Uses the same rules as <tt>ActiveRecord::Base.exists?</tt>.
+      # [collection.build(attributes = {}, ...)]
+      #   Returns one or more new objects of the collection type that have been instantiated
+      #   with +attributes+ and linked to this object through a foreign key, but have not yet
+      #   been saved.
+      # [collection.create(attributes = {})]
+      #   Returns a new object of the collection type that has been instantiated
+      #   with +attributes+, linked to this object through a foreign key, and that has already
+      #   been saved (if it passed the validation). *Note*: This only works if the base model
+      #   already exists in the DB, not if it is a new (unsaved) record!
+      # [collection.create!(attributes = {})]
+      #   Does the same as <tt>collection.create</tt>, but raises <tt>ActiveRecord::RecordInvalid</tt>
+      #   if the record is invalid.
+      #
+      # === Example
+      #
+      # A <tt>Firm</tt> class declares <tt>has_many :clients</tt>, which will add:
+      # * <tt>Firm#clients</tt> (similar to <tt>Client.where(firm_id: id)</tt>)
+      # * <tt>Firm#clients<<</tt>
+      # * <tt>Firm#clients.delete</tt>
+      # * <tt>Firm#clients.destroy</tt>
+      # * <tt>Firm#clients=</tt>
+      # * <tt>Firm#client_ids</tt>
+      # * <tt>Firm#client_ids=</tt>
+      # * <tt>Firm#clients.clear</tt>
+      # * <tt>Firm#clients.empty?</tt> (similar to <tt>firm.clients.size == 0</tt>)
+      # * <tt>Firm#clients.size</tt> (similar to <tt>Client.count "firm_id = #{id}"</tt>)
+      # * <tt>Firm#clients.find</tt> (similar to <tt>Client.where(firm_id: id).find(id)</tt>)
+      # * <tt>Firm#clients.exists?(name: 'ACME')</tt> (similar to <tt>Client.exists?(name: 'ACME', firm_id: firm.id)</tt>)
+      # * <tt>Firm#clients.build</tt> (similar to <tt>Client.new("firm_id" => id)</tt>)
+      # * <tt>Firm#clients.create</tt> (similar to <tt>c = Client.new("firm_id" => id); c.save; c</tt>)
+      # * <tt>Firm#clients.create!</tt> (similar to <tt>c = Client.new("firm_id" => id); c.save!</tt>)
+      # The declaration can also include an +options+ hash to specialize the behavior of the association.
+      #
+      # === Options
+      # [:class_name]
+      #   Specify the class name of the association. Use it only if that name can't be inferred
+      #   from the association name. So <tt>has_many :products</tt> will by default be linked
+      #   to the Product class, but if the real class name is SpecialProduct, you'll have to
+      #   specify it with this option.
+      # [:foreign_key]
+      #   Specify the foreign key used for the association. By default this is guessed to be the name
+      #   of this class in lower-case and "_id" suffixed. So a Person class that makes a +has_many+
+      #   association will use "person_id" as the default <tt>:foreign_key</tt>.
+      # [:primary_key]
+      #   Specify the method that returns the primary key used for the association. By default this is +id+.
+      # [:dependent]
+      #   Controls what happens to the associated objects when
+      #   their owner is destroyed. Note that these are implemented as
+      #   callbacks, and Rails executes callbacks in order. Therefore, other
+      #   similar callbacks may affect the <tt>:dependent</tt> behavior, and the
+      #   <tt>:dependent</tt> behavior may affect other callbacks.
+      #
+      #   * <tt>:destroy</tt> causes all the associated objects to also be destroyed.
+      #   * <tt>:delete_all</tt> causes all the associated objects to be deleted directly from the database (so callbacks will not be executed).
+      #   * <tt>:nullify</tt> causes the foreign keys to be set to +NULL+. Callbacks are not executed.
+      #   * <tt>:restrict_with_exception</tt> causes an exception to be raised if there are any associated records.
+      #   * <tt>:restrict_with_error</tt> causes an error to be added to the owner if there are any associated objects.
+      #
+      #   If using with the <tt>:through</tt> option, the association on the join model must be
+      #   a +belongs_to+, and the records which get deleted are the join records, rather than
+      #   the associated records.
+      # [:counter_cache]
+      #   This option can be used to configure a custom named <tt>:counter_cache.</tt> You only need this option,
+      #   when you customized the name of your <tt>:counter_cache</tt> on the <tt>belongs_to</tt> association.
+      # [:as]
+      #   Specifies a polymorphic interface (See <tt>belongs_to</tt>).
+      # [:through]
+      #   Specifies an association through which to perform the query. This can be any other type
+      #   of association, including other <tt>:through</tt> associations. Options for <tt>:class_name</tt>,
+      #   <tt>:primary_key</tt> and <tt>:foreign_key</tt> are ignored, as the association uses the
+      #   source reflection.
+      #
+      #   If the association on the join model is a +belongs_to+, the collection can be modified
+      #   and the records on the <tt>:through</tt> model will be automatically created and removed
+      #   as appropriate. Otherwise, the collection is read-only, so you should manipulate the
+      #   <tt>:through</tt> association directly.
+      #
+      #   If you are going to modify the association (rather than just read from it), then it is
+      #   a good idea to set the <tt>:inverse_of</tt> option on the source association on the
+      #   join model. This allows associated records to be built which will automatically create
+      #   the appropriate join model records when they are saved. (See the 'Association Join Models'
+      #   section above.)
+      # [:source]
+      #   Specifies the source association name used by <tt>has_many :through</tt> queries.
+      #   Only use it if the name cannot be inferred from the association.
+      #   <tt>has_many :subscribers, through: :subscriptions</tt> will look for either <tt>:subscribers</tt> or
+      #   <tt>:subscriber</tt> on Subscription, unless a <tt>:source</tt> is given.
+      # [:source_type]
+      #   Specifies type of the source association used by <tt>has_many :through</tt> queries where the source
+      #   association is a polymorphic +belongs_to+.
+      # [:validate]
+      #   If +false+, don't validate the associated objects when saving the parent object. true by default.
+      # [:autosave]
+      #   If true, always save the associated objects or destroy them if marked for destruction,
+      #   when saving the parent object. If false, never save or destroy the associated objects.
+      #   By default, only save associated objects that are new records. This option is implemented as a
+      #   +before_save+ callback. Because callbacks are run in the order they are defined, associated objects
+      #   may need to be explicitly saved in any user-defined +before_save+ callbacks.
+      #
+      #   Note that <tt>accepts_nested_attributes_for</tt> sets <tt>:autosave</tt> to <tt>true</tt>.
+      # [:inverse_of]
+      #   Specifies the name of the <tt>belongs_to</tt> association on the associated object
+      #   that is the inverse of this <tt>has_many</tt> association. Does not work in combination
+      #   with <tt>:through</tt> or <tt>:as</tt> options.
+      #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
+      #
+      # Option examples:
+      #   has_many :comments, -> { order "posted_on" }
+      #   has_many :comments, -> { includes :author }
+      #   has_many :people, -> { where("deleted = 0").order("name") }, class_name: "Person"
+      #   has_many :tracks, -> { order "position" }, dependent: :destroy
+      #   has_many :comments, dependent: :nullify
+      #   has_many :tags, as: :taggable
+      #   has_many :reports, -> { readonly }
+      #   has_many :subscribers, through: :subscriptions, source: :user
+      def has_many(name, scope = nil, options = {}, &extension)
+        reflection = Builder::HasMany.build(self, name, scope, options, &extension)
+        Reflection.add_reflection self, name, reflection
+      end
+
+      # Specifies a one-to-one association with another class. This method should only be used
+      # if the other class contains the foreign key. If the current class contains the foreign key,
+      # then you should use +belongs_to+ instead. See also ActiveRecord::Associations::ClassMethods's overview
+      # on when to use +has_one+ and when to use +belongs_to+.
+      #
+      # The following methods for retrieval and query of a single associated object will be added:
+      #
+      # +association+ is a placeholder for the symbol passed as the +name+ argument, so
+      # <tt>has_one :manager</tt> would add among others <tt>manager.nil?</tt>.
+      #
+      # [association(force_reload = false)]
+      #   Returns the associated object. +nil+ is returned if none is found.
+      # [association=(associate)]
+      #   Assigns the associate object, extracts the primary key, sets it as the foreign key,
+      #   and saves the associate object. To avoid database inconsistencies, permanently deletes an existing
+      #   associated object when assigning a new one, even if the new one isn't saved to database.
+      # [build_association(attributes = {})]
+      #   Returns a new object of the associated type that has been instantiated
+      #   with +attributes+ and linked to this object through a foreign key, but has not
+      #   yet been saved.
+      # [create_association(attributes = {})]
+      #   Returns a new object of the associated type that has been instantiated
+      #   with +attributes+, linked to this object through a foreign key, and that
+      #   has already been saved (if it passed the validation).
+      # [create_association!(attributes = {})]
+      #   Does the same as <tt>create_association</tt>, but raises <tt>ActiveRecord::RecordInvalid</tt>
+      #   if the record is invalid.
+      #
+      # === Example
+      #
+      # An Account class declares <tt>has_one :beneficiary</tt>, which will add:
+      # * <tt>Account#beneficiary</tt> (similar to <tt>Beneficiary.where(account_id: id).first</tt>)
+      # * <tt>Account#beneficiary=(beneficiary)</tt> (similar to <tt>beneficiary.account_id = account.id; beneficiary.save</tt>)
+      # * <tt>Account#build_beneficiary</tt> (similar to <tt>Beneficiary.new("account_id" => id)</tt>)
+      # * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>)
+      # * <tt>Account#create_beneficiary!</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save!; b</tt>)
+      #
+      # === Options
+      #
+      # The declaration can also include an +options+ hash to specialize the behavior of the association.
+      #
+      # Options are:
+      # [:class_name]
+      #   Specify the class name of the association. Use it only if that name can't be inferred
+      #   from the association name. So <tt>has_one :manager</tt> will by default be linked to the Manager class, but
+      #   if the real class name is Person, you'll have to specify it with this option.
+      # [:dependent]
+      #   Controls what happens to the associated object when
+      #   its owner is destroyed:
+      #
+      #   * <tt>:destroy</tt> causes the associated object to also be destroyed
+      #   * <tt>:delete</tt> causes the associated object to be deleted directly from the database (so callbacks will not execute)
+      #   * <tt>:nullify</tt> causes the foreign key to be set to +NULL+. Callbacks are not executed.
+      #   * <tt>:restrict_with_exception</tt> causes an exception to be raised if there is an associated record
+      #   * <tt>:restrict_with_error</tt> causes an error to be added to the owner if there is an associated object
+      # [:foreign_key]
+      #   Specify the foreign key used for the association. By default this is guessed to be the name
+      #   of this class in lower-case and "_id" suffixed. So a Person class that makes a +has_one+ association
+      #   will use "person_id" as the default <tt>:foreign_key</tt>.
+      # [:primary_key]
+      #   Specify the method that returns the primary key used for the association. By default this is +id+.
+      # [:as]
+      #   Specifies a polymorphic interface (See <tt>belongs_to</tt>).
+      # [:through]
+      #   Specifies a Join Model through which to perform the query. Options for <tt>:class_name</tt>,
+      #   <tt>:primary_key</tt>, and <tt>:foreign_key</tt> are ignored, as the association uses the
+      #   source reflection. You can only use a <tt>:through</tt> query through a <tt>has_one</tt>
+      #   or <tt>belongs_to</tt> association on the join model.
+      # [:source]
+      #   Specifies the source association name used by <tt>has_one :through</tt> queries.
+      #   Only use it if the name cannot be inferred from the association.
+      #   <tt>has_one :favorite, through: :favorites</tt> will look for a
+      #   <tt>:favorite</tt> on Favorite, unless a <tt>:source</tt> is given.
+      # [:source_type]
+      #   Specifies type of the source association used by <tt>has_one :through</tt> queries where the source
+      #   association is a polymorphic +belongs_to+.
+      # [:validate]
+      #   If +false+, don't validate the associated object when saving the parent object. +false+ by default.
+      # [:autosave]
+      #   If true, always save the associated object or destroy it if marked for destruction,
+      #   when saving the parent object. If false, never save or destroy the associated object.
+      #   By default, only save the associated object if it's a new record.
+      #
+      #   Note that <tt>accepts_nested_attributes_for</tt> sets <tt>:autosave</tt> to <tt>true</tt>.
+      # [:inverse_of]
+      #   Specifies the name of the <tt>belongs_to</tt> association on the associated object
+      #   that is the inverse of this <tt>has_one</tt> association. Does not work in combination
+      #   with <tt>:through</tt> or <tt>:as</tt> options.
+      #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
+      # [:required]
+      #   When set to +true+, the association will also have its presence validated.
+      #   This will validate the association itself, not the id. You can use
+      #   +:inverse_of+ to avoid an extra query during validation.
+      #
+      # Option examples:
+      #   has_one :credit_card, dependent: :destroy  # destroys the associated credit card
+      #   has_one :credit_card, dependent: :nullify  # updates the associated records foreign
+      #                                                 # key value to NULL rather than destroying it
+      #   has_one :last_comment, -> { order 'posted_on' }, class_name: "Comment"
+      #   has_one :project_manager, -> { where role: 'project_manager' }, class_name: "Person"
+      #   has_one :attachment, as: :attachable
+      #   has_one :boss, readonly: :true
+      #   has_one :club, through: :membership
+      #   has_one :primary_address, -> { where primary: true }, through: :addressables, source: :addressable
+      #   has_one :credit_card, required: true
+      def has_one(name, scope = nil, options = {})
+        reflection = Builder::HasOne.build(self, name, scope, options)
+        Reflection.add_reflection self, name, reflection
+      end
+
+      # Specifies a one-to-one association with another class. This method should only be used
+      # if this class contains the foreign key. If the other class contains the foreign key,
+      # then you should use +has_one+ instead. See also ActiveRecord::Associations::ClassMethods's overview
+      # on when to use +has_one+ and when to use +belongs_to+.
+      #
+      # Methods will be added for retrieval and query for a single associated object, for which
+      # this object holds an id:
+      #
+      # +association+ is a placeholder for the symbol passed as the +name+ argument, so
+      # <tt>belongs_to :author</tt> would add among others <tt>author.nil?</tt>.
+      #
+      # [association(force_reload = false)]
+      #   Returns the associated object. +nil+ is returned if none is found.
+      # [association=(associate)]
+      #   Assigns the associate object, extracts the primary key, and sets it as the foreign key.
+      # [build_association(attributes = {})]
+      #   Returns a new object of the associated type that has been instantiated
+      #   with +attributes+ and linked to this object through a foreign key, but has not yet been saved.
+      # [create_association(attributes = {})]
+      #   Returns a new object of the associated type that has been instantiated
+      #   with +attributes+, linked to this object through a foreign key, and that
+      #   has already been saved (if it passed the validation).
+      # [create_association!(attributes = {})]
+      #   Does the same as <tt>create_association</tt>, but raises <tt>ActiveRecord::RecordInvalid</tt>
+      #   if the record is invalid.
+      #
+      # === Example
+      #
+      # A Post class declares <tt>belongs_to :author</tt>, which will add:
+      # * <tt>Post#author</tt> (similar to <tt>Author.find(author_id)</tt>)
+      # * <tt>Post#author=(author)</tt> (similar to <tt>post.author_id = author.id</tt>)
+      # * <tt>Post#build_author</tt> (similar to <tt>post.author = Author.new</tt>)
+      # * <tt>Post#create_author</tt> (similar to <tt>post.author = Author.new; post.author.save; post.author</tt>)
+      # * <tt>Post#create_author!</tt> (similar to <tt>post.author = Author.new; post.author.save!; post.author</tt>)
+      # The declaration can also include an +options+ hash to specialize the behavior of the association.
+      #
+      # === Options
+      #
+      # [:class_name]
+      #   Specify the class name of the association. Use it only if that name can't be inferred
+      #   from the association name. So <tt>belongs_to :author</tt> will by default be linked to the Author class, but
+      #   if the real class name is Person, you'll have to specify it with this option.
+      # [:foreign_key]
+      #   Specify the foreign key used for the association. By default this is guessed to be the name
+      #   of the association with an "_id" suffix. So a class that defines a <tt>belongs_to :person</tt>
+      #   association will use "person_id" as the default <tt>:foreign_key</tt>. Similarly,
+      #   <tt>belongs_to :favorite_person, class_name: "Person"</tt> will use a foreign key
+      #   of "favorite_person_id".
+      # [:foreign_type]
+      #   Specify the column used to store the associated object's type, if this is a polymorphic
+      #   association. By default this is guessed to be the name of the association with a "_type"
+      #   suffix. So a class that defines a <tt>belongs_to :taggable, polymorphic: true</tt>
+      #   association will use "taggable_type" as the default <tt>:foreign_type</tt>.
+      # [:primary_key]
+      #   Specify the method that returns the primary key of associated object used for the association.
+      #   By default this is id.
+      # [:dependent]
+      #   If set to <tt>:destroy</tt>, the associated object is destroyed when this object is. If set to
+      #   <tt>:delete</tt>, the associated object is deleted *without* calling its destroy method.
+      #   This option should not be specified when <tt>belongs_to</tt> is used in conjunction with
+      #   a <tt>has_many</tt> relationship on another class because of the potential to leave
+      #   orphaned records behind.
+      # [:counter_cache]
+      #   Caches the number of belonging objects on the associate class through the use of +increment_counter+
+      #   and +decrement_counter+. The counter cache is incremented when an object of this
+      #   class is created and decremented when it's destroyed. This requires that a column
+      #   named <tt>#{table_name}_count</tt> (such as +comments_count+ for a belonging Comment class)
+      #   is used on the associate class (such as a Post class) - that is the migration for
+      #   <tt>#{table_name}_count</tt> is created on the associate class (such that <tt>Post.comments_count</tt> will
+      #   return the count cached, see note below). You can also specify a custom counter
+      #   cache column by providing a column name instead of a +true+/+false+ value to this
+      #   option (e.g., <tt>counter_cache: :my_custom_counter</tt>.)
+      #   Note: Specifying a counter cache will add it to that model's list of readonly attributes
+      #   using +attr_readonly+.
+      # [:polymorphic]
+      #   Specify this association is a polymorphic association by passing +true+.
+      #   Note: If you've enabled the counter cache, then you may want to add the counter cache attribute
+      #   to the +attr_readonly+ list in the associated classes (e.g. <tt>class Post; attr_readonly :comments_count; end</tt>).
+      # [:validate]
+      #   If +false+, don't validate the associated objects when saving the parent object. +false+ by default.
+      # [:autosave]
+      #   If true, always save the associated object or destroy it if marked for destruction, when
+      #   saving the parent object.
+      #   If false, never save or destroy the associated object.
+      #   By default, only save the associated object if it's a new record.
+      #
+      #   Note that <tt>accepts_nested_attributes_for</tt> sets <tt>:autosave</tt> to <tt>true</tt>.
+      # [:touch]
+      #   If true, the associated object will be touched (the updated_at/on attributes set to current time)
+      #   when this record is either saved or destroyed. If you specify a symbol, that attribute
+      #   will be updated with the current time in addition to the updated_at/on attribute.
+      # [:inverse_of]
+      #   Specifies the name of the <tt>has_one</tt> or <tt>has_many</tt> association on the associated
+      #   object that is the inverse of this <tt>belongs_to</tt> association. Does not work in
+      #   combination with the <tt>:polymorphic</tt> options.
+      #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
+      # [:required]
+      #   When set to +true+, the association will also have its presence validated.
+      #   This will validate the association itself, not the id. You can use
+      #   +:inverse_of+ to avoid an extra query during validation.
+      #
+      # Option examples:
+      #   belongs_to :firm, foreign_key: "client_of"
+      #   belongs_to :person, primary_key: "name", foreign_key: "person_name"
+      #   belongs_to :author, class_name: "Person", foreign_key: "author_id"
+      #   belongs_to :valid_coupon, ->(o) { where "discounts > #{o.payments_count}" },
+      #                             class_name: "Coupon", foreign_key: "coupon_id"
+      #   belongs_to :attachable, polymorphic: true
+      #   belongs_to :project, readonly: true
+      #   belongs_to :post, counter_cache: true
+      #   belongs_to :company, touch: true
+      #   belongs_to :company, touch: :employees_last_updated_at
+      #   belongs_to :company, required: true
+      def belongs_to(name, scope = nil, options = {})
+        reflection = Builder::BelongsTo.build(self, name, scope, options)
+        Reflection.add_reflection self, name, reflection
+      end
+
+      # Specifies a many-to-many relationship with another class. This associates two classes via an
+      # intermediate join table. Unless the join table is explicitly specified as an option, it is
+      # guessed using the lexical order of the class names. So a join between Developer and Project
+      # will give the default join table name of "developers_projects" because "D" precedes "P" alphabetically.
+      # Note that this precedence is calculated using the <tt><</tt> operator for String. This
+      # means that if the strings are of different lengths, and the strings are equal when compared
+      # up to the shortest length, then the longer string is considered of higher
+      # lexical precedence than the shorter one. For example, one would expect the tables "paper_boxes" and "papers"
+      # to generate a join table name of "papers_paper_boxes" because of the length of the name "paper_boxes",
+      # but it in fact generates a join table name of "paper_boxes_papers". Be aware of this caveat, and use the
+      # custom <tt>:join_table</tt> option if you need to.
+      # If your tables share a common prefix, it will only appear once at the beginning. For example,
+      # the tables "catalog_categories" and "catalog_products" generate a join table name of "catalog_categories_products".
+      #
+      # The join table should not have a primary key or a model associated with it. You must manually generate the
+      # join table with a migration such as this:
+      #
+      #   class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration
+      #     def change
+      #       create_table :developers_projects, id: false do |t|
+      #         t.integer :developer_id
+      #         t.integer :project_id
+      #       end
+      #     end
+      #   end
+      #
+      # It's also a good idea to add indexes to each of those columns to speed up the joins process.
+      # However, in MySQL it is advised to add a compound index for both of the columns as MySQL only
+      # uses one index per table during the lookup.
+      #
+      # Adds the following methods for retrieval and query:
+      #
+      # +collection+ is a placeholder for the symbol passed as the +name+ argument, so
+      # <tt>has_and_belongs_to_many :categories</tt> would add among others <tt>categories.empty?</tt>.
+      #
+      # [collection(force_reload = false)]
+      #   Returns an array of all the associated objects.
+      #   An empty array is returned if none are found.
+      # [collection<<(object, ...)]
+      #   Adds one or more objects to the collection by creating associations in the join table
+      #   (<tt>collection.push</tt> and <tt>collection.concat</tt> are aliases to this method).
+      #   Note that this operation instantly fires update SQL without waiting for the save or update call on the
+      #   parent object, unless the parent object is a new record.
+      # [collection.delete(object, ...)]
+      #   Removes one or more objects from the collection by removing their associations from the join table.
+      #   This does not destroy the objects.
+      # [collection.destroy(object, ...)]
+      #   Removes one or more objects from the collection by running destroy on each association in the join table, overriding any dependent option.
+      #   This does not destroy the objects.
+      # [collection=objects]
+      #   Replaces the collection's content by deleting and adding objects as appropriate.
+      # [collection_singular_ids]
+      #   Returns an array of the associated objects' ids.
+      # [collection_singular_ids=ids]
+      #   Replace the collection by the objects identified by the primary keys in +ids+.
+      # [collection.clear]
+      #   Removes every object from the collection. This does not destroy the objects.
+      # [collection.empty?]
+      #   Returns +true+ if there are no associated objects.
+      # [collection.size]
+      #   Returns the number of associated objects.
+      # [collection.find(id)]
+      #   Finds an associated object responding to the +id+ and that
+      #   meets the condition that it has to be associated with this object.
+      #   Uses the same rules as <tt>ActiveRecord::Base.find</tt>.
+      # [collection.exists?(...)]
+      #   Checks whether an associated object with the given conditions exists.
+      #   Uses the same rules as <tt>ActiveRecord::Base.exists?</tt>.
+      # [collection.build(attributes = {})]
+      #   Returns a new object of the collection type that has been instantiated
+      #   with +attributes+ and linked to this object through the join table, but has not yet been saved.
+      # [collection.create(attributes = {})]
+      #   Returns a new object of the collection type that has been instantiated
+      #   with +attributes+, linked to this object through the join table, and that has already been
+      #   saved (if it passed the validation).
+      #
+      # === Example
+      #
+      # A Developer class declares <tt>has_and_belongs_to_many :projects</tt>, which will add:
+      # * <tt>Developer#projects</tt>
+      # * <tt>Developer#projects<<</tt>
+      # * <tt>Developer#projects.delete</tt>
+      # * <tt>Developer#projects.destroy</tt>
+      # * <tt>Developer#projects=</tt>
+      # * <tt>Developer#project_ids</tt>
+      # * <tt>Developer#project_ids=</tt>
+      # * <tt>Developer#projects.clear</tt>
+      # * <tt>Developer#projects.empty?</tt>
+      # * <tt>Developer#projects.size</tt>
+      # * <tt>Developer#projects.find(id)</tt>
+      # * <tt>Developer#projects.exists?(...)</tt>
+      # * <tt>Developer#projects.build</tt> (similar to <tt>Project.new("developer_id" => id)</tt>)
+      # * <tt>Developer#projects.create</tt> (similar to <tt>c = Project.new("developer_id" => id); c.save; c</tt>)
+      # The declaration may include an +options+ hash to specialize the behavior of the association.
+      #
+      # === Options
+      #
+      # [:class_name]
+      #   Specify the class name of the association. Use it only if that name can't be inferred
+      #   from the association name. So <tt>has_and_belongs_to_many :projects</tt> will by default be linked to the
+      #   Project class, but if the real class name is SuperProject, you'll have to specify it with this option.
+      # [:join_table]
+      #   Specify the name of the join table if the default based on lexical order isn't what you want.
+      #   <b>WARNING:</b> If you're overwriting the table name of either class, the +table_name+ method
+      #   MUST be declared underneath any +has_and_belongs_to_many+ declaration in order to work.
+      # [:foreign_key]
+      #   Specify the foreign key used for the association. By default this is guessed to be the name
+      #   of this class in lower-case and "_id" suffixed. So a Person class that makes
+      #   a +has_and_belongs_to_many+ association to Project will use "person_id" as the
+      #   default <tt>:foreign_key</tt>.
+      # [:association_foreign_key]
+      #   Specify the foreign key used for the association on the receiving side of the association.
+      #   By default this is guessed to be the name of the associated class in lower-case and "_id" suffixed.
+      #   So if a Person class makes a +has_and_belongs_to_many+ association to Project,
+      #   the association will use "project_id" as the default <tt>:association_foreign_key</tt>.
+      # [:readonly]
+      #   If true, all the associated objects are readonly through the association.
+      # [:validate]
+      #   If +false+, don't validate the associated objects when saving the parent object. +true+ by default.
+      # [:autosave]
+      #   If true, always save the associated objects or destroy them if marked for destruction, when
+      #   saving the parent object.
+      #   If false, never save or destroy the associated objects.
+      #   By default, only save associated objects that are new records.
+      #
+      #   Note that <tt>accepts_nested_attributes_for</tt> sets <tt>:autosave</tt> to <tt>true</tt>.
+      #
+      # Option examples:
+      #   has_and_belongs_to_many :projects
+      #   has_and_belongs_to_many :projects, -> { includes :milestones, :manager }
+      #   has_and_belongs_to_many :nations, class_name: "Country"
+      #   has_and_belongs_to_many :categories, join_table: "prods_cats"
+      #   has_and_belongs_to_many :categories, -> { readonly }
+      def has_and_belongs_to_many(name, scope = nil, options = {}, &extension)
+        if scope.is_a?(Hash)
+          options = scope
+          scope   = nil
+        end
+
+        habtm_reflection = ActiveRecord::Reflection::HasAndBelongsToManyReflection.new(name, scope, options, self)
+
+        builder = Builder::HasAndBelongsToMany.new name, self, options
+
+        join_model = builder.through_model
+
+        # FIXME: we should move this to the internal constants. Also people
+        # should never directly access this constant so I'm not happy about
+        # setting it.
+        const_set join_model.name, join_model
+
+        middle_reflection = builder.middle_reflection join_model
+
+        Builder::HasMany.define_callbacks self, middle_reflection
+        Reflection.add_reflection self, middle_reflection.name, middle_reflection
+        middle_reflection.parent_reflection = [name.to_s, habtm_reflection]
+
+        include Module.new {
+          class_eval <<-RUBY, __FILE__, __LINE__ + 1
+          def destroy_associations
+            association(:#{middle_reflection.name}).delete_all(:delete_all)
+            association(:#{name}).reset
+            super
+          end
+          RUBY
+        }
+
+        hm_options = {}
+        hm_options[:through] = middle_reflection.name
+        hm_options[:source] = join_model.right_reflection.name
+
+        [:before_add, :after_add, :before_remove, :after_remove, :autosave, :validate, :join_table].each do |k|
+          hm_options[k] = options[k] if options.key? k
+        end
+
+        has_many name, scope, hm_options, &extension
+        self._reflections[name.to_s].parent_reflection = [name.to_s, habtm_reflection]
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/alias_tracker.rb b/activerecord/lib/active_record/associations/alias_tracker.rb
new file mode 100644
index 0000000000..a6a1947148
--- /dev/null
+++ b/activerecord/lib/active_record/associations/alias_tracker.rb
@@ -0,0 +1,96 @@
+require 'active_support/core_ext/string/conversions'
+
+module ActiveRecord
+  module Associations
+    # Keeps track of table aliases for ActiveRecord::Associations::ClassMethods::JoinDependency and
+    # ActiveRecord::Associations::ThroughAssociationScope
+    class AliasTracker # :nodoc:
+      attr_reader :aliases, :connection
+
+      def self.empty(connection)
+        new connection, Hash.new(0)
+      end
+
+      def self.create(connection, table_joins)
+        if table_joins.empty?
+          empty connection
+        else
+          aliases = Hash.new { |h,k|
+            h[k] = initial_count_for(connection, k, table_joins)
+          }
+          new connection, aliases
+        end
+      end
+
+      def self.initial_count_for(connection, name, table_joins)
+        # quoted_name should be downcased as some database adapters (Oracle) return quoted name in uppercase
+        quoted_name = connection.quote_table_name(name).downcase
+
+        counts = table_joins.map do |join|
+          if join.is_a?(Arel::Nodes::StringJoin)
+            # Table names + table aliases
+            join.left.downcase.scan(
+              /join(?:\s+\w+)?\s+(\S+\s+)?#{quoted_name}\son/
+            ).size
+          elsif join.respond_to? :left
+            join.left.table_name == name ? 1 : 0
+          else
+            # this branch is reached by two tests:
+            #
+            # activerecord/test/cases/associations/cascaded_eager_loading_test.rb:37
+            #   with :posts
+            #
+            # activerecord/test/cases/associations/eager_test.rb:1133
+            #   with :comments
+            #
+            0
+          end
+        end
+
+        counts.sum
+      end
+
+      # table_joins is an array of arel joins which might conflict with the aliases we assign here
+      def initialize(connection, aliases)
+        @aliases    = aliases
+        @connection = connection
+      end
+
+      def aliased_table_for(table_name, aliased_name)
+        table_alias = aliased_name_for(table_name, aliased_name)
+
+        if table_alias == table_name
+          Arel::Table.new(table_name)
+        else
+          Arel::Table.new(table_name).alias(table_alias)
+        end
+      end
+
+      def aliased_name_for(table_name, aliased_name)
+        if aliases[table_name].zero?
+          # If it's zero, we can have our table_name
+          aliases[table_name] = 1
+          table_name
+        else
+          # Otherwise, we need to use an alias
+          aliased_name = connection.table_alias_for(aliased_name)
+
+          # Update the count
+          aliases[aliased_name] += 1
+
+          if aliases[aliased_name] > 1
+            "#{truncate(aliased_name)}_#{aliases[aliased_name]}"
+          else
+            aliased_name
+          end
+        end
+      end
+
+      private
+
+        def truncate(name)
+          name.slice(0, connection.table_alias_length - 2)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
new file mode 100644
index 0000000000..f1c36cd047
--- /dev/null
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -0,0 +1,253 @@
+require 'active_support/core_ext/array/wrap'
+
+module ActiveRecord
+  module Associations
+    # = Active Record Associations
+    #
+    # This is the root class of all associations ('+ Foo' signifies an included module Foo):
+    #
+    #   Association
+    #     SingularAssociation
+    #       HasOneAssociation
+    #         HasOneThroughAssociation + ThroughAssociation
+    #       BelongsToAssociation
+    #         BelongsToPolymorphicAssociation
+    #     CollectionAssociation
+    #       HasManyAssociation
+    #         HasManyThroughAssociation + ThroughAssociation
+    class Association #:nodoc:
+      attr_reader :owner, :target, :reflection
+      attr_accessor :inversed
+
+      delegate :options, :to => :reflection
+
+      def initialize(owner, reflection)
+        reflection.check_validity!
+
+        @owner, @reflection = owner, reflection
+
+        reset
+        reset_scope
+      end
+
+      # Returns the name of the table of the associated class:
+      #
+      #   post.comments.aliased_table_name # => "comments"
+      #
+      def aliased_table_name
+        klass.table_name
+      end
+
+      # Resets the \loaded flag to +false+ and sets the \target to +nil+.
+      def reset
+        @loaded = false
+        @target = nil
+        @stale_state = nil
+        @inversed = false
+      end
+
+      # Reloads the \target and returns +self+ on success.
+      def reload
+        reset
+        reset_scope
+        load_target
+        self unless target.nil?
+      end
+
+      # Has the \target been already \loaded?
+      def loaded?
+        @loaded
+      end
+
+      # Asserts the \target has been loaded setting the \loaded flag to +true+.
+      def loaded!
+        @loaded = true
+        @stale_state = stale_state
+        @inversed = false
+      end
+
+      # The target is stale if the target no longer points to the record(s) that the
+      # relevant foreign_key(s) refers to. If stale, the association accessor method
+      # on the owner will reload the target. It's up to subclasses to implement the
+      # stale_state method if relevant.
+      #
+      # Note that if the target has not been loaded, it is not considered stale.
+      def stale_target?
+        !inversed && loaded? && @stale_state != stale_state
+      end
+
+      # Sets the target of this association to <tt>\target</tt>, and the \loaded flag to +true+.
+      def target=(target)
+        @target = target
+        loaded!
+      end
+
+      def scope
+        target_scope.merge(association_scope)
+      end
+
+      # The scope for this association.
+      #
+      # Note that the association_scope is merged into the target_scope only when the
+      # scope method is called. This is because at that point the call may be surrounded
+      # by scope.scoping { ... } or with_scope { ... } etc, which affects the scope which
+      # actually gets built.
+      def association_scope
+        if klass
+          @association_scope ||= AssociationScope.scope(self, klass.connection)
+        end
+      end
+
+      def reset_scope
+        @association_scope = nil
+      end
+
+      # Set the inverse association, if possible
+      def set_inverse_instance(record)
+        if invertible_for?(record)
+          inverse = record.association(inverse_reflection_for(record).name)
+          inverse.target = owner
+          inverse.inversed = true
+        end
+        record
+      end
+
+      # Returns the class of the target. belongs_to polymorphic overrides this to look at the
+      # polymorphic_type field on the owner.
+      def klass
+        reflection.klass
+      end
+
+      # Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e. the
+      # through association's scope)
+      def target_scope
+        AssociationRelation.create(klass, klass.arel_table, self).merge!(klass.all)
+      end
+
+      # Loads the \target if needed and returns it.
+      #
+      # This method is abstract in the sense that it relies on +find_target+,
+      # which is expected to be provided by descendants.
+      #
+      # If the \target is already \loaded it is just returned. Thus, you can call
+      # +load_target+ unconditionally to get the \target.
+      #
+      # ActiveRecord::RecordNotFound is rescued within the method, and it is
+      # not reraised. The proxy is \reset and +nil+ is the return value.
+      def load_target
+        @target = find_target if (@stale_state && stale_target?) || find_target?
+
+        loaded! unless loaded?
+        target
+      rescue ActiveRecord::RecordNotFound
+        reset
+      end
+
+      def interpolate(sql, record = nil)
+        if sql.respond_to?(:to_proc)
+          owner.instance_exec(record, &sql)
+        else
+          sql
+        end
+      end
+
+      # We can't dump @reflection since it contains the scope proc
+      def marshal_dump
+        ivars = (instance_variables - [:@reflection]).map { |name| [name, instance_variable_get(name)] }
+        [@reflection.name, ivars]
+      end
+
+      def marshal_load(data)
+        reflection_name, ivars = data
+        ivars.each { |name, val| instance_variable_set(name, val) }
+        @reflection = @owner.class._reflect_on_association(reflection_name)
+      end
+
+      def initialize_attributes(record) #:nodoc:
+        skip_assign = [reflection.foreign_key, reflection.type].compact
+        attributes = create_scope.except(*(record.changed - skip_assign))
+        record.assign_attributes(attributes)
+        set_inverse_instance(record)
+      end
+
+      private
+
+        def find_target?
+          !loaded? && (!owner.new_record? || foreign_key_present?) && klass
+        end
+
+        def creation_attributes
+          attributes = {}
+
+          if (reflection.has_one? || reflection.collection?) && !options[:through]
+            attributes[reflection.foreign_key] = owner[reflection.active_record_primary_key]
+
+            if reflection.options[:as]
+              attributes[reflection.type] = owner.class.base_class.name
+            end
+          end
+
+          attributes
+        end
+
+        # Sets the owner attributes on the given record
+        def set_owner_attributes(record)
+          creation_attributes.each { |key, value| record[key] = value }
+        end
+
+        # Returns true if there is a foreign key present on the owner which
+        # references the target. This is used to determine whether we can load
+        # the target if the owner is currently a new record (and therefore
+        # without a key). If the owner is a new record then foreign_key must
+        # be present in order to load target.
+        #
+        # Currently implemented by belongs_to (vanilla and polymorphic) and
+        # has_one/has_many :through associations which go through a belongs_to.
+        def foreign_key_present?
+          false
+        end
+
+        # Raises ActiveRecord::AssociationTypeMismatch unless +record+ is of
+        # the kind of the class of the associated objects. Meant to be used as
+        # a sanity check when you are about to assign an associated record.
+        def raise_on_type_mismatch!(record)
+          unless record.is_a?(reflection.klass) || record.is_a?(reflection.class_name.constantize)
+            message = "#{reflection.class_name}(##{reflection.klass.object_id}) expected, got #{record.class}(##{record.class.object_id})"
+            raise ActiveRecord::AssociationTypeMismatch, message
+          end
+        end
+
+        # Can be redefined by subclasses, notably polymorphic belongs_to
+        # The record parameter is necessary to support polymorphic inverses as we must check for
+        # the association in the specific class of the record.
+        def inverse_reflection_for(record)
+          reflection.inverse_of
+        end
+
+        # Returns true if inverse association on the given record needs to be set.
+        # This method is redefined by subclasses.
+        def invertible_for?(record)
+          foreign_key_for?(record) && inverse_reflection_for(record)
+        end
+
+        # Returns true if record contains the foreign_key
+        def foreign_key_for?(record)
+          record.has_attribute?(reflection.foreign_key)
+        end
+
+        # This should be implemented to return the values of the relevant key(s) on the owner,
+        # so that when stale_state is different from the value stored on the last find_target,
+        # the target is stale.
+        #
+        # This is only relevant to certain associations, which is why it returns nil by default.
+        def stale_state
+        end
+
+        def build_record(attributes)
+          reflection.build_association(attributes) do |record|
+            initialize_attributes(record)
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/association_scope.rb b/activerecord/lib/active_record/associations/association_scope.rb
new file mode 100644
index 0000000000..519d4d8651
--- /dev/null
+++ b/activerecord/lib/active_record/associations/association_scope.rb
@@ -0,0 +1,182 @@
+module ActiveRecord
+  module Associations
+    class AssociationScope #:nodoc:
+      def self.scope(association, connection)
+        INSTANCE.scope association, connection
+      end
+
+      class BindSubstitution
+        def initialize(block)
+          @block = block
+        end
+
+        def bind_value(scope, column, value, alias_tracker)
+          substitute = alias_tracker.connection.substitute_at(
+            column, scope.bind_values.length)
+          scope.bind_values += [[column, @block.call(value)]]
+          substitute
+        end
+      end
+
+      def self.create(&block)
+        block = block ? block : lambda { |val| val }
+        new BindSubstitution.new(block)
+      end
+
+      def initialize(bind_substitution)
+        @bind_substitution = bind_substitution
+      end
+
+      INSTANCE = create
+
+      def scope(association, connection)
+        klass         = association.klass
+        reflection    = association.reflection
+        scope         = klass.unscoped
+        owner         = association.owner
+        alias_tracker = AliasTracker.empty connection
+
+        scope.extending! Array(reflection.options[:extend])
+        add_constraints(scope, owner, klass, reflection, alias_tracker)
+      end
+
+      def join_type
+        Arel::Nodes::InnerJoin
+      end
+
+      def self.get_bind_values(owner, chain)
+        bvs = []
+        chain.each_with_index do |reflection, i|
+          if reflection == chain.last
+            bvs << reflection.join_id_for(owner)
+            if reflection.type
+              bvs << owner.class.base_class.name
+            end
+          else
+            if reflection.type
+              bvs << chain[i + 1].klass.base_class.name
+            end
+          end
+        end
+        bvs
+      end
+
+      private
+
+      def construct_tables(chain, klass, refl, alias_tracker)
+        chain.map do |reflection|
+          alias_tracker.aliased_table_for(
+            table_name_for(reflection, klass, refl),
+            table_alias_for(reflection, refl, reflection != refl)
+          )
+        end
+      end
+
+      def table_alias_for(reflection, refl, join = false)
+        name = "#{reflection.plural_name}_#{alias_suffix(refl)}"
+        name << "_join" if join
+        name
+      end
+
+      def join(table, constraint)
+        table.create_join(table, table.create_on(constraint), join_type)
+      end
+
+      def column_for(table_name, column_name, alias_tracker)
+        columns = alias_tracker.connection.schema_cache.columns_hash(table_name)
+        columns[column_name]
+      end
+
+      def bind_value(scope, column, value, alias_tracker)
+        @bind_substitution.bind_value scope, column, value, alias_tracker
+      end
+
+      def bind(scope, table_name, column_name, value, tracker)
+        column   = column_for table_name, column_name, tracker
+        bind_value scope, column, value, tracker
+      end
+
+      def add_constraints(scope, owner, assoc_klass, refl, tracker)
+        chain = refl.chain
+        scope_chain = refl.scope_chain
+
+        tables = construct_tables(chain, assoc_klass, refl, tracker)
+
+        chain.each_with_index do |reflection, i|
+          table, foreign_table = tables.shift, tables.first
+
+          join_keys = reflection.join_keys(assoc_klass)
+          key = join_keys.key
+          foreign_key = join_keys.foreign_key
+
+          if reflection == chain.last
+            bind_val = bind scope, table.table_name, key.to_s, owner[foreign_key], tracker
+            scope    = scope.where(table[key].eq(bind_val))
+
+            if reflection.type
+              value    = owner.class.base_class.name
+              bind_val = bind scope, table.table_name, reflection.type.to_s, value, tracker
+              scope    = scope.where(table[reflection.type].eq(bind_val))
+            end
+          else
+            constraint = table[key].eq(foreign_table[foreign_key])
+
+            if reflection.type
+              value    = chain[i + 1].klass.base_class.name
+              bind_val = bind scope, table.table_name, reflection.type.to_s, value, tracker
+              scope    = scope.where(table[reflection.type].eq(bind_val))
+            end
+
+            scope = scope.joins(join(foreign_table, constraint))
+          end
+
+          is_first_chain = i == 0
+          klass = is_first_chain ? assoc_klass : reflection.klass
+
+          # Exclude the scope of the association itself, because that
+          # was already merged in the #scope method.
+          scope_chain[i].each do |scope_chain_item|
+            item  = eval_scope(klass, scope_chain_item, owner)
+
+            if scope_chain_item == refl.scope
+              scope.merge! item.except(:where, :includes, :bind)
+            end
+
+            if is_first_chain
+              scope.includes! item.includes_values
+            end
+
+            scope.where_values += item.where_values
+            scope.bind_values  += item.bind_values
+            scope.order_values |= item.order_values
+          end
+        end
+
+        scope
+      end
+
+      def alias_suffix(refl)
+        refl.name
+      end
+
+      def table_name_for(reflection, klass, refl)
+        if reflection == refl
+          # If this is a polymorphic belongs_to, we want to get the klass from the
+          # association because it depends on the polymorphic_type attribute of
+          # the owner
+          klass.table_name
+        else
+          reflection.table_name
+        end
+      end
+
+      def eval_scope(klass, scope, owner)
+        if scope.is_a?(Relation)
+          scope
+        else
+          klass.unscoped.instance_exec(owner, &scope)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
new file mode 100644
index 0000000000..81fdd681de
--- /dev/null
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -0,0 +1,111 @@
+module ActiveRecord
+  # = Active Record Belongs To Association
+  module Associations
+    class BelongsToAssociation < SingularAssociation #:nodoc:
+
+      def handle_dependency
+        target.send(options[:dependent]) if load_target
+      end
+
+      def replace(record)
+        if record
+          raise_on_type_mismatch!(record)
+          update_counters(record)
+          replace_keys(record)
+          set_inverse_instance(record)
+          @updated = true
+        else
+          decrement_counters
+          remove_keys
+        end
+
+        self.target = record
+      end
+
+      def reset
+        super
+        @updated = false
+      end
+
+      def updated?
+        @updated
+      end
+
+      def decrement_counters # :nodoc:
+        with_cache_name { |name| decrement_counter name }
+      end
+
+      def increment_counters # :nodoc:
+        with_cache_name { |name| increment_counter name }
+      end
+
+      private
+
+        def find_target?
+          !loaded? && foreign_key_present? && klass
+        end
+
+        def with_cache_name
+          counter_cache_name = reflection.counter_cache_column
+          return unless counter_cache_name && owner.persisted?
+          yield counter_cache_name
+        end
+
+        def update_counters(record)
+          with_cache_name do |name|
+            return unless different_target? record
+            record.class.increment_counter(name, record.id)
+            decrement_counter name
+          end
+        end
+
+        def decrement_counter(counter_cache_name)
+          if foreign_key_present?
+            klass.decrement_counter(counter_cache_name, target_id)
+          end
+        end
+
+        def increment_counter(counter_cache_name)
+          if foreign_key_present?
+            klass.increment_counter(counter_cache_name, target_id)
+          end
+        end
+
+        # Checks whether record is different to the current target, without loading it
+        def different_target?(record)
+          record.id != owner[reflection.foreign_key]
+        end
+
+        def replace_keys(record)
+          owner[reflection.foreign_key] = record[reflection.association_primary_key(record.class)]
+        end
+
+        def remove_keys
+          owner[reflection.foreign_key] = nil
+        end
+
+        def foreign_key_present?
+          owner[reflection.foreign_key]
+        end
+
+        # NOTE - for now, we're only supporting inverse setting from belongs_to back onto
+        # has_one associations.
+        def invertible_for?(record)
+          inverse = inverse_reflection_for(record)
+          inverse && inverse.has_one?
+        end
+
+        def target_id
+          if options[:primary_key]
+            owner.send(reflection.name).try(:id)
+          else
+            owner[reflection.foreign_key]
+          end
+        end
+
+        def stale_state
+          owner[reflection.foreign_key] && owner[reflection.foreign_key].to_s
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/belongs_to_polymorphic_association.rb b/activerecord/lib/active_record/associations/belongs_to_polymorphic_association.rb
new file mode 100644
index 0000000000..b710cf6bdb
--- /dev/null
+++ b/activerecord/lib/active_record/associations/belongs_to_polymorphic_association.rb
@@ -0,0 +1,40 @@
+module ActiveRecord
+  # = Active Record Belongs To Polymorphic Association
+  module Associations
+    class BelongsToPolymorphicAssociation < BelongsToAssociation #:nodoc:
+      def klass
+        type = owner[reflection.foreign_type]
+        type.presence && type.constantize
+      end
+
+      private
+
+        def replace_keys(record)
+          super
+          owner[reflection.foreign_type] = record.class.base_class.name
+        end
+
+        def remove_keys
+          super
+          owner[reflection.foreign_type] = nil
+        end
+
+        def different_target?(record)
+          super || record.class != klass
+        end
+
+        def inverse_reflection_for(record)
+          reflection.polymorphic_inverse_of(record.class)
+        end
+
+        def raise_on_type_mismatch!(record)
+          # A polymorphic association cannot have a type mismatch, by definition
+        end
+
+        def stale_state
+          foreign_key = super
+          foreign_key && [foreign_key.to_s, owner[reflection.foreign_type].to_s]
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/association.rb b/activerecord/lib/active_record/associations/builder/association.rb
new file mode 100644
index 0000000000..947d61ee7b
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/association.rb
@@ -0,0 +1,149 @@
+require 'active_support/core_ext/module/attribute_accessors'
+
+# This is the parent Association class which defines the variables
+# used by all associations.
+#
+# The hierarchy is defined as follows:
+#  Association
+#    - SingularAssociation
+#      - BelongsToAssociation
+#      - HasOneAssociation
+#    - CollectionAssociation
+#      - HasManyAssociation
+
+module ActiveRecord::Associations::Builder
+  class Association #:nodoc:
+    class << self
+      attr_accessor :extensions
+      # TODO: This class accessor is needed to make activerecord-deprecated_finders work.
+      # We can move it to a constant in 5.0.
+      attr_accessor :valid_options
+    end
+    self.extensions = []
+
+    self.valid_options = [:class_name, :class, :foreign_key, :validate]
+
+    attr_reader :name, :scope, :options
+
+    def self.build(model, name, scope, options, &block)
+      if model.dangerous_attribute_method?(name)
+        raise ArgumentError, "You tried to define an association named #{name} on the model #{model.name}, but " \
+                             "this will conflict with a method #{name} already defined by Active Record. " \
+                             "Please choose a different association name."
+      end
+
+      builder = create_builder model, name, scope, options, &block
+      reflection = builder.build(model)
+      define_accessors model, reflection
+      define_callbacks model, reflection
+      define_validations model, reflection
+      builder.define_extensions model
+      reflection
+    end
+
+    def self.create_builder(model, name, scope, options, &block)
+      raise ArgumentError, "association names must be a Symbol" unless name.kind_of?(Symbol)
+
+      new(model, name, scope, options, &block)
+    end
+
+    def initialize(model, name, scope, options)
+      # TODO: Move this to create_builder as soon we drop support to activerecord-deprecated_finders.
+      if scope.is_a?(Hash)
+        options = scope
+        scope   = nil
+      end
+
+      # TODO: Remove this model argument as soon we drop support to activerecord-deprecated_finders.
+      @name    = name
+      @scope   = scope
+      @options = options
+
+      validate_options
+
+      if scope && scope.arity == 0
+        @scope = proc { instance_exec(&scope) }
+      end
+    end
+
+    def build(model)
+      ActiveRecord::Reflection.create(macro, name, scope, options, model)
+    end
+
+    def macro
+      raise NotImplementedError
+    end
+
+    def valid_options
+      Association.valid_options + Association.extensions.flat_map(&:valid_options)
+    end
+
+    def validate_options
+      options.assert_valid_keys(valid_options)
+    end
+
+    def define_extensions(model)
+    end
+
+    def self.define_callbacks(model, reflection)
+      if dependent = reflection.options[:dependent]
+        check_dependent_options(dependent)
+        add_destroy_callbacks(model, reflection)
+      end
+
+      Association.extensions.each do |extension|
+        extension.build model, reflection
+      end
+    end
+
+    # Defines the setter and getter methods for the association
+    # class Post < ActiveRecord::Base
+    #   has_many :comments
+    # end
+    #
+    # Post.first.comments and Post.first.comments= methods are defined by this method...
+    def self.define_accessors(model, reflection)
+      mixin = model.generated_association_methods
+      name = reflection.name
+      define_readers(mixin, name)
+      define_writers(mixin, name)
+    end
+
+    def self.define_readers(mixin, name)
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name}(*args)
+          association(:#{name}).reader(*args)
+        end
+      CODE
+    end
+
+    def self.define_writers(mixin, name)
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name}=(value)
+          association(:#{name}).writer(value)
+        end
+      CODE
+    end
+
+    def self.define_validations(model, reflection)
+      # noop
+    end
+
+    def self.valid_dependent_options
+      raise NotImplementedError
+    end
+
+    private
+
+    def self.check_dependent_options(dependent)
+      unless valid_dependent_options.include? dependent
+        raise ArgumentError, "The :dependent option must be one of #{valid_dependent_options}, but is :#{dependent}"
+      end
+    end
+
+    def self.add_destroy_callbacks(model, reflection)
+      name = reflection.name
+      model.before_destroy lambda { |o| o.association(name).handle_dependency }
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/belongs_to.rb b/activerecord/lib/active_record/associations/builder/belongs_to.rb
new file mode 100644
index 0000000000..954ea3878a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/belongs_to.rb
@@ -0,0 +1,116 @@
+module ActiveRecord::Associations::Builder
+  class BelongsTo < SingularAssociation #:nodoc:
+    def macro
+      :belongs_to
+    end
+
+    def valid_options
+      super + [:foreign_type, :polymorphic, :touch, :counter_cache]
+    end
+
+    def self.valid_dependent_options
+      [:destroy, :delete]
+    end
+
+    def self.define_callbacks(model, reflection)
+      super
+      add_counter_cache_callbacks(model, reflection) if reflection.options[:counter_cache]
+      add_touch_callbacks(model, reflection)         if reflection.options[:touch]
+    end
+
+    def self.define_accessors(mixin, reflection)
+      super
+      add_counter_cache_methods mixin
+    end
+
+    private
+
+    def self.add_counter_cache_methods(mixin)
+      return if mixin.method_defined? :belongs_to_counter_cache_after_update
+
+      mixin.class_eval do
+        def belongs_to_counter_cache_after_update(reflection)
+          foreign_key  = reflection.foreign_key
+          cache_column = reflection.counter_cache_column
+
+          if (@_after_create_counter_called ||= false)
+            @_after_create_counter_called = false
+          elsif attribute_changed?(foreign_key) && !new_record? && reflection.constructable?
+            model           = reflection.klass
+            foreign_key_was = attribute_was foreign_key
+            foreign_key     = attribute foreign_key
+
+            if foreign_key && model.respond_to?(:increment_counter)
+              model.increment_counter(cache_column, foreign_key)
+            end
+            if foreign_key_was && model.respond_to?(:decrement_counter)
+              model.decrement_counter(cache_column, foreign_key_was)
+            end
+          end
+        end
+      end
+    end
+
+    def self.add_counter_cache_callbacks(model, reflection)
+      cache_column = reflection.counter_cache_column
+
+      model.after_update lambda { |record|
+        record.belongs_to_counter_cache_after_update(reflection)
+      }
+
+      klass = reflection.class_name.safe_constantize
+      klass.attr_readonly cache_column if klass && klass.respond_to?(:attr_readonly)
+    end
+
+    def self.touch_record(o, foreign_key, name, touch) # :nodoc:
+      old_foreign_id = o.changed_attributes[foreign_key]
+
+      if old_foreign_id
+        association = o.association(name)
+        reflection = association.reflection
+        if reflection.polymorphic?
+          klass = o.public_send("#{reflection.foreign_type}_was").constantize
+        else
+          klass = association.klass
+        end
+        old_record = klass.find_by(klass.primary_key => old_foreign_id)
+
+        if old_record
+          if touch != true
+            old_record.touch touch
+          else
+            old_record.touch
+          end
+        end
+      end
+
+      record = o.send name
+      if record && record.persisted?
+        if touch != true
+          record.touch touch
+        else
+          record.touch
+        end
+      end
+    end
+
+    def self.add_touch_callbacks(model, reflection)
+      foreign_key = reflection.foreign_key
+      n           = reflection.name
+      touch       = reflection.options[:touch]
+
+      callback = lambda { |record|
+        BelongsTo.touch_record(record, foreign_key, n, touch)
+      }
+
+      model.after_save    callback, if: :changed?
+      model.after_touch   callback
+      model.after_destroy callback
+    end
+
+    def self.add_destroy_callbacks(model, reflection)
+      name = reflection.name
+      model.after_destroy lambda { |o| o.association(name).handle_dependency }
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/collection_association.rb b/activerecord/lib/active_record/associations/builder/collection_association.rb
new file mode 100644
index 0000000000..bc15a49996
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/collection_association.rb
@@ -0,0 +1,91 @@
+# This class is inherited by the has_many and has_many_and_belongs_to_many association classes
+
+require 'active_record/associations'
+
+module ActiveRecord::Associations::Builder
+  class CollectionAssociation < Association #:nodoc:
+
+    CALLBACKS = [:before_add, :after_add, :before_remove, :after_remove]
+
+    def valid_options
+      super + [:table_name, :before_add,
+               :after_add, :before_remove, :after_remove, :extend]
+    end
+
+    attr_reader :block_extension
+
+    def initialize(model, name, scope, options)
+      super
+      @mod = nil
+      if block_given?
+        @mod = Module.new(&Proc.new)
+        @scope = wrap_scope @scope, @mod
+      end
+    end
+
+    def self.define_callbacks(model, reflection)
+      super
+      name    = reflection.name
+      options = reflection.options
+      CALLBACKS.each { |callback_name|
+        define_callback(model, callback_name, name, options)
+      }
+    end
+
+    def define_extensions(model)
+      if @mod
+        extension_module_name = "#{model.name.demodulize}#{name.to_s.camelize}AssociationExtension"
+        model.parent.const_set(extension_module_name, @mod)
+      end
+    end
+
+    def self.define_callback(model, callback_name, name, options)
+      full_callback_name = "#{callback_name}_for_#{name}"
+
+      # TODO : why do i need method_defined? I think its because of the inheritance chain
+      model.class_attribute full_callback_name unless model.method_defined?(full_callback_name)
+      callbacks = Array(options[callback_name.to_sym]).map do |callback|
+        case callback
+        when Symbol
+          ->(method, owner, record) { owner.send(callback, record) }
+        when Proc
+          ->(method, owner, record) { callback.call(owner, record) }
+        else
+          ->(method, owner, record) { callback.send(method, owner, record) }
+        end
+      end
+      model.send "#{full_callback_name}=", callbacks
+    end
+
+    # Defines the setter and getter methods for the collection_singular_ids.
+    def self.define_readers(mixin, name)
+      super
+
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name.to_s.singularize}_ids
+          association(:#{name}).ids_reader
+        end
+      CODE
+    end
+
+    def self.define_writers(mixin, name)
+      super
+
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name.to_s.singularize}_ids=(ids)
+          association(:#{name}).ids_writer(ids)
+        end
+      CODE
+    end
+
+    private
+
+    def wrap_scope(scope, mod)
+      if scope
+        proc { |owner| instance_exec(owner, &scope).extending(mod) }
+      else
+        proc { extending(mod) }
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
new file mode 100644
index 0000000000..34a555dfd4
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
@@ -0,0 +1,124 @@
+module ActiveRecord::Associations::Builder
+  class HasAndBelongsToMany # :nodoc:
+    class JoinTableResolver
+      KnownTable = Struct.new :join_table
+
+      class KnownClass
+        def initialize(lhs_class, rhs_class_name)
+          @lhs_class      = lhs_class
+          @rhs_class_name = rhs_class_name
+          @join_table     = nil
+        end
+
+        def join_table
+          @join_table ||= [@lhs_class.table_name, klass.table_name].sort.join("\0").gsub(/^(.*[._])(.+)\0\1(.+)/, '\1\2_\3').gsub("\0", "_")
+        end
+
+        private
+
+        def klass
+          @lhs_class.send(:compute_type, @rhs_class_name)
+        end
+      end
+
+      def self.build(lhs_class, name, options)
+        if options[:join_table]
+          KnownTable.new options[:join_table].to_s
+        else
+          class_name = options.fetch(:class_name) {
+            name.to_s.camelize.singularize
+          }
+          KnownClass.new lhs_class, class_name
+        end
+      end
+    end
+
+    attr_reader :lhs_model, :association_name, :options
+
+    def initialize(association_name, lhs_model, options)
+      @association_name = association_name
+      @lhs_model = lhs_model
+      @options = options
+    end
+
+    def through_model
+      habtm = JoinTableResolver.build lhs_model, association_name, options
+
+      join_model = Class.new(ActiveRecord::Base) {
+        class << self;
+          attr_accessor :class_resolver
+          attr_accessor :name
+          attr_accessor :table_name_resolver
+          attr_accessor :left_reflection
+          attr_accessor :right_reflection
+        end
+
+        def self.table_name
+          table_name_resolver.join_table
+        end
+
+        def self.compute_type(class_name)
+          class_resolver.compute_type class_name
+        end
+
+        def self.add_left_association(name, options)
+          belongs_to name, options
+          self.left_reflection = _reflect_on_association(name)
+        end
+
+        def self.add_right_association(name, options)
+          rhs_name = name.to_s.singularize.to_sym
+          belongs_to rhs_name, options
+          self.right_reflection = _reflect_on_association(rhs_name)
+        end
+
+      }
+
+      join_model.name                = "HABTM_#{association_name.to_s.camelize}"
+      join_model.table_name_resolver = habtm
+      join_model.class_resolver      = lhs_model
+
+      join_model.add_left_association :left_side, class: lhs_model
+      join_model.add_right_association association_name, belongs_to_options(options)
+      join_model
+    end
+
+    def middle_reflection(join_model)
+      middle_name = [lhs_model.name.downcase.pluralize,
+                     association_name].join('_').gsub(/::/, '_').to_sym
+      middle_options = middle_options join_model
+      hm_builder = HasMany.create_builder(lhs_model,
+                                          middle_name,
+                                          nil,
+                                          middle_options)
+      hm_builder.build lhs_model
+    end
+
+    private
+
+    def middle_options(join_model)
+      middle_options = {}
+      middle_options[:class] = join_model
+      middle_options[:source] = join_model.left_reflection.name
+      if options.key? :foreign_key
+        middle_options[:foreign_key] = options[:foreign_key]
+      end
+      middle_options
+    end
+
+    def belongs_to_options(options)
+      rhs_options = {}
+
+      if options.key? :class_name
+        rhs_options[:foreign_key] = options[:class_name].foreign_key
+        rhs_options[:class_name] = options[:class_name]
+      end
+
+      if options.key? :association_foreign_key
+        rhs_options[:foreign_key] = options[:association_foreign_key]
+      end
+
+      rhs_options
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/has_many.rb b/activerecord/lib/active_record/associations/builder/has_many.rb
new file mode 100644
index 0000000000..4c8c826f76
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_many.rb
@@ -0,0 +1,15 @@
+module ActiveRecord::Associations::Builder
+  class HasMany < CollectionAssociation #:nodoc:
+    def macro
+      :has_many
+    end
+
+    def valid_options
+      super + [:primary_key, :dependent, :as, :through, :source, :source_type, :inverse_of, :counter_cache, :join_table]
+    end
+
+    def self.valid_dependent_options
+      [:destroy, :delete_all, :nullify, :restrict_with_error, :restrict_with_exception]
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/has_one.rb b/activerecord/lib/active_record/associations/builder/has_one.rb
new file mode 100644
index 0000000000..c194c8ae9a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_one.rb
@@ -0,0 +1,23 @@
+module ActiveRecord::Associations::Builder
+  class HasOne < SingularAssociation #:nodoc:
+    def macro
+      :has_one
+    end
+
+    def valid_options
+      valid = super + [:as]
+      valid += [:through, :source, :source_type] if options[:through]
+      valid
+    end
+
+    def self.valid_dependent_options
+      [:destroy, :delete, :nullify, :restrict_with_error, :restrict_with_exception]
+    end
+
+    private
+
+    def self.add_destroy_callbacks(model, reflection)
+      super unless reflection.options[:through]
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/builder/singular_association.rb b/activerecord/lib/active_record/associations/builder/singular_association.rb
new file mode 100644
index 0000000000..6e6dd7204c
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/singular_association.rb
@@ -0,0 +1,38 @@
+# This class is inherited by the has_one and belongs_to association classes
+
+module ActiveRecord::Associations::Builder
+  class SingularAssociation < Association #:nodoc:
+    def valid_options
+      super + [:dependent, :primary_key, :inverse_of, :required]
+    end
+
+    def self.define_accessors(model, reflection)
+      super
+      define_constructors(model.generated_association_methods, reflection.name) if reflection.constructable?
+    end
+
+    # Defines the (build|create)_association methods for belongs_to or has_one association
+    def self.define_constructors(mixin, name)
+      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def build_#{name}(*args, &block)
+          association(:#{name}).build(*args, &block)
+        end
+
+        def create_#{name}(*args, &block)
+          association(:#{name}).create(*args, &block)
+        end
+
+        def create_#{name}!(*args, &block)
+          association(:#{name}).create!(*args, &block)
+        end
+      CODE
+    end
+
+    def self.define_validations(model, reflection)
+      super
+      if reflection.options[:required]
+        model.validates_presence_of reflection.name
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
new file mode 100644
index 0000000000..065a2cff01
--- /dev/null
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -0,0 +1,606 @@
+module ActiveRecord
+  module Associations
+    # = Active Record Association Collection
+    #
+    # CollectionAssociation is an abstract class that provides common stuff to
+    # ease the implementation of association proxies that represent
+    # collections. See the class hierarchy in Association.
+    #
+    #   CollectionAssociation:
+    #     HasManyAssociation => has_many
+    #       HasManyThroughAssociation + ThroughAssociation => has_many :through
+    #
+    # CollectionAssociation class provides common methods to the collections
+    # defined by +has_and_belongs_to_many+, +has_many+ or +has_many+ with
+    # +:through association+ option.
+    #
+    # You need to be careful with assumptions regarding the target: The proxy
+    # does not fetch records from the database until it needs them, but new
+    # ones created with +build+ are added to the target. So, the target may be
+    # non-empty and still lack children waiting to be read from the database.
+    # If you look directly to the database you cannot assume that's the entire
+    # collection because new records may have been added to the target, etc.
+    #
+    # If you need to work on all current children, new and existing records,
+    # +load_target+ and the +loaded+ flag are your friends.
+    class CollectionAssociation < Association #:nodoc:
+
+      # Implements the reader method, e.g. foo.items for Foo.has_many :items
+      def reader(force_reload = false)
+        if force_reload
+          klass.uncached { reload }
+        elsif stale_target?
+          reload
+        end
+
+        @proxy ||= CollectionProxy.create(klass, self)
+      end
+
+      # Implements the writer method, e.g. foo.items= for Foo.has_many :items
+      def writer(records)
+        replace(records)
+      end
+
+      # Implements the ids reader method, e.g. foo.item_ids for Foo.has_many :items
+      def ids_reader
+        if loaded?
+          load_target.map do |record|
+            record.send(reflection.association_primary_key)
+          end
+        else
+          column  = "#{reflection.quoted_table_name}.#{reflection.association_primary_key}"
+          scope.pluck(column)
+        end
+      end
+
+      # Implements the ids writer method, e.g. foo.item_ids= for Foo.has_many :items
+      def ids_writer(ids)
+        pk_type = reflection.primary_key_type
+        ids = Array(ids).reject { |id| id.blank? }
+        ids.map! { |i| pk_type.type_cast_from_user(i) }
+        replace(klass.find(ids).index_by { |r| r.id }.values_at(*ids))
+      end
+
+      def reset
+        super
+        @target = []
+      end
+
+      def select(*fields)
+        if block_given?
+          load_target.select.each { |e| yield e }
+        else
+          scope.select(*fields)
+        end
+      end
+
+      def find(*args)
+        if block_given?
+          load_target.find(*args) { |*block_args| yield(*block_args) }
+        else
+          if options[:inverse_of] && loaded?
+            args_flatten = args.flatten
+            raise RecordNotFound, "Couldn't find #{scope.klass.name} without an ID" if args_flatten.blank?
+            result = find_by_scan(*args)
+
+            result_size = Array(result).size
+            if !result || result_size != args_flatten.size
+              scope.raise_record_not_found_exception!(args_flatten, result_size, args_flatten.size)
+            else
+              result
+            end
+          else
+            scope.find(*args)
+          end
+        end
+      end
+
+      def first(*args)
+        first_nth_or_last(:first, *args)
+      end
+
+      def second(*args)
+        first_nth_or_last(:second, *args)
+      end
+
+      def third(*args)
+        first_nth_or_last(:third, *args)
+      end
+
+      def fourth(*args)
+        first_nth_or_last(:fourth, *args)
+      end
+
+      def fifth(*args)
+        first_nth_or_last(:fifth, *args)
+      end
+
+      def forty_two(*args)
+        first_nth_or_last(:forty_two, *args)
+      end
+
+      def last(*args)
+        first_nth_or_last(:last, *args)
+      end
+
+      def build(attributes = {}, &block)
+        if attributes.is_a?(Array)
+          attributes.collect { |attr| build(attr, &block) }
+        else
+          add_to_target(build_record(attributes)) do |record|
+            yield(record) if block_given?
+          end
+        end
+      end
+
+      def create(attributes = {}, &block)
+        _create_record(attributes, &block)
+      end
+
+      def create!(attributes = {}, &block)
+        _create_record(attributes, true, &block)
+      end
+
+      # Add +records+ to this association. Returns +self+ so method calls may
+      # be chained. Since << flattens its argument list and inserts each record,
+      # +push+ and +concat+ behave identically.
+      def concat(*records)
+        if owner.new_record?
+          load_target
+          concat_records(records)
+        else
+          transaction { concat_records(records) }
+        end
+      end
+
+      # Starts a transaction in the association class's database connection.
+      #
+      #   class Author < ActiveRecord::Base
+      #     has_many :books
+      #   end
+      #
+      #   Author.first.books.transaction do
+      #     # same effect as calling Book.transaction
+      #   end
+      def transaction(*args)
+        reflection.klass.transaction(*args) do
+          yield
+        end
+      end
+
+      # Removes all records from the association without calling callbacks
+      # on the associated records. It honors the `:dependent` option. However
+      # if the `:dependent` value is `:destroy` then in that case the `:delete_all`
+      # deletion strategy for the association is applied.
+      #
+      # You can force a particular deletion strategy by passing a parameter.
+      #
+      # Example:
+      #
+      # @author.books.delete_all(:nullify)
+      # @author.books.delete_all(:delete_all)
+      #
+      # See delete for more info.
+      def delete_all(dependent = nil)
+        if dependent && ![:nullify, :delete_all].include?(dependent)
+          raise ArgumentError, "Valid values are :nullify or :delete_all"
+        end
+
+        dependent = if dependent
+                      dependent
+                    elsif options[:dependent] == :destroy
+                      :delete_all
+                    else
+                      options[:dependent]
+                    end
+
+        delete_or_nullify_all_records(dependent).tap do
+          reset
+          loaded!
+        end
+      end
+
+      # Destroy all the records from this association.
+      #
+      # See destroy for more info.
+      def destroy_all
+        destroy(load_target).tap do
+          reset
+          loaded!
+        end
+      end
+
+      # Count all records using SQL.  Construct options and pass them with
+      # scope to the target class's +count+.
+      def count(column_name = nil, count_options = {})
+        # TODO: Remove count_options argument as soon we remove support to
+        # activerecord-deprecated_finders.
+        column_name, count_options = nil, column_name if column_name.is_a?(Hash)
+
+        relation = scope
+        if association_scope.distinct_value
+          # This is needed because 'SELECT count(DISTINCT *)..' is not valid SQL.
+          column_name ||= reflection.klass.primary_key
+          relation = relation.distinct
+        end
+
+        value = relation.count(column_name)
+
+        limit  = options[:limit]
+        offset = options[:offset]
+
+        if limit || offset
+          [ [value - offset.to_i, 0].max, limit.to_i ].min
+        else
+          value
+        end
+      end
+
+      # Removes +records+ from this association calling +before_remove+ and
+      # +after_remove+ callbacks.
+      #
+      # This method is abstract in the sense that +delete_records+ has to be
+      # provided by descendants. Note this method does not imply the records
+      # are actually removed from the database, that depends precisely on
+      # +delete_records+. They are in any case removed from the collection.
+      def delete(*records)
+        return if records.empty?
+        _options = records.extract_options!
+        dependent = _options[:dependent] || options[:dependent]
+
+        records = find(records) if records.any? { |record| record.kind_of?(Fixnum) || record.kind_of?(String) }
+        delete_or_destroy(records, dependent)
+      end
+
+      # Deletes the +records+ and removes them from this association calling
+      # +before_remove+ , +after_remove+ , +before_destroy+ and +after_destroy+ callbacks.
+      #
+      # Note that this method removes records from the database ignoring the
+      # +:dependent+ option.
+      def destroy(*records)
+        return if records.empty?
+        records = find(records) if records.any? { |record| record.kind_of?(Fixnum) || record.kind_of?(String) }
+        delete_or_destroy(records, :destroy)
+      end
+
+      # Returns the size of the collection by executing a SELECT COUNT(*)
+      # query if the collection hasn't been loaded, and calling
+      # <tt>collection.size</tt> if it has.
+      #
+      # If the collection has been already loaded +size+ and +length+ are
+      # equivalent. If not and you are going to need the records anyway
+      # +length+ will take one less query. Otherwise +size+ is more efficient.
+      #
+      # This method is abstract in the sense that it relies on
+      # +count_records+, which is a method descendants have to provide.
+      def size
+        if !find_target? || loaded?
+          if association_scope.distinct_value
+            target.uniq.size
+          else
+            target.size
+          end
+        elsif !loaded? && !association_scope.group_values.empty?
+          load_target.size
+        elsif !loaded? && !association_scope.distinct_value && target.is_a?(Array)
+          unsaved_records = target.select { |r| r.new_record? }
+          unsaved_records.size + count_records
+        else
+          count_records
+        end
+      end
+
+      # Returns the size of the collection calling +size+ on the target.
+      #
+      # If the collection has been already loaded +length+ and +size+ are
+      # equivalent. If not and you are going to need the records anyway this
+      # method will take one less query. Otherwise +size+ is more efficient.
+      def length
+        load_target.size
+      end
+
+      # Returns true if the collection is empty.
+      #
+      # If the collection has been loaded
+      # it is equivalent to <tt>collection.size.zero?</tt>. If the
+      # collection has not been loaded, it is equivalent to
+      # <tt>collection.exists?</tt>. If the collection has not already been
+      # loaded and you are going to fetch the records anyway it is better to
+      # check <tt>collection.length.zero?</tt>.
+      def empty?
+        if loaded?
+          size.zero?
+        else
+          @target.blank? && !scope.exists?
+        end
+      end
+
+      # Returns true if the collections is not empty.
+      # Equivalent to +!collection.empty?+.
+      def any?
+        if block_given?
+          load_target.any? { |*block_args| yield(*block_args) }
+        else
+          !empty?
+        end
+      end
+
+      # Returns true if the collection has more than 1 record.
+      # Equivalent to +collection.size > 1+.
+      def many?
+        if block_given?
+          load_target.many? { |*block_args| yield(*block_args) }
+        else
+          size > 1
+        end
+      end
+
+      def distinct
+        seen = {}
+        load_target.find_all do |record|
+          seen[record.id] = true unless seen.key?(record.id)
+        end
+      end
+      alias uniq distinct
+
+      # Replace this collection with +other_array+. This will perform a diff
+      # and delete/add only records that have changed.
+      def replace(other_array)
+        other_array.each { |val| raise_on_type_mismatch!(val) }
+        original_target = load_target.dup
+
+        if owner.new_record?
+          replace_records(other_array, original_target)
+        else
+          if other_array != original_target
+            transaction { replace_records(other_array, original_target) }
+          end
+        end
+      end
+
+      def include?(record)
+        if record.is_a?(reflection.klass)
+          if record.new_record?
+            include_in_memory?(record)
+          else
+            loaded? ? target.include?(record) : scope.exists?(record.id)
+          end
+        else
+          false
+        end
+      end
+
+      def load_target
+        if find_target?
+          @target = merge_target_lists(find_target, target)
+        end
+
+        loaded!
+        target
+      end
+
+      def add_to_target(record, skip_callbacks = false)
+        callback(:before_add, record) unless skip_callbacks
+        yield(record) if block_given?
+
+        if association_scope.distinct_value && index = @target.index(record)
+          @target[index] = record
+        else
+          @target << record
+        end
+
+        callback(:after_add, record) unless skip_callbacks
+        set_inverse_instance(record)
+
+        record
+      end
+
+      def scope(opts = {})
+        scope = super()
+        scope.none! if opts.fetch(:nullify, true) && null_scope?
+        scope
+      end
+
+      def null_scope?
+        owner.new_record? && !foreign_key_present?
+      end
+
+      private
+      def get_records
+        return scope.to_a if reflection.scope_chain.any?(&:any?)
+
+        conn = klass.connection
+        sc = reflection.association_scope_cache(conn, owner) do
+          StatementCache.create(conn) { |params|
+            as = AssociationScope.create { params.bind }
+            target_scope.merge as.scope(self, conn)
+          }
+        end
+
+        binds = AssociationScope.get_bind_values(owner, reflection.chain)
+        sc.execute binds, klass, klass.connection
+      end
+
+        def find_target
+          records = get_records
+          records.each { |record| set_inverse_instance(record) }
+          records
+        end
+
+        # We have some records loaded from the database (persisted) and some that are
+        # in-memory (memory). The same record may be represented in the persisted array
+        # and in the memory array.
+        #
+        # So the task of this method is to merge them according to the following rules:
+        #
+        #   * The final array must not have duplicates
+        #   * The order of the persisted array is to be preserved
+        #   * Any changes made to attributes on objects in the memory array are to be preserved
+        #   * Otherwise, attributes should have the value found in the database
+        def merge_target_lists(persisted, memory)
+          return persisted if memory.empty?
+          return memory    if persisted.empty?
+
+          persisted.map! do |record|
+            if mem_record = memory.delete(record)
+
+              ((record.attribute_names & mem_record.attribute_names) - mem_record.changes.keys).each do |name|
+                mem_record[name] = record[name]
+              end
+
+              mem_record
+            else
+              record
+            end
+          end
+
+          persisted + memory
+        end
+
+        def _create_record(attributes, raise = false, &block)
+          unless owner.persisted?
+            raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
+          end
+
+          if attributes.is_a?(Array)
+            attributes.collect { |attr| _create_record(attr, raise, &block) }
+          else
+            transaction do
+              add_to_target(build_record(attributes)) do |record|
+                yield(record) if block_given?
+                insert_record(record, true, raise)
+              end
+            end
+          end
+        end
+
+        # Do the relevant stuff to insert the given record into the association collection.
+        def insert_record(record, validate = true, raise = false)
+          raise NotImplementedError
+        end
+
+        def create_scope
+          scope.scope_for_create.stringify_keys
+        end
+
+        def delete_or_destroy(records, method)
+          records = records.flatten
+          records.each { |record| raise_on_type_mismatch!(record) }
+          existing_records = records.reject { |r| r.new_record? }
+
+          if existing_records.empty?
+            remove_records(existing_records, records, method)
+          else
+            transaction { remove_records(existing_records, records, method) }
+          end
+        end
+
+        def remove_records(existing_records, records, method)
+          records.each { |record| callback(:before_remove, record) }
+
+          delete_records(existing_records, method) if existing_records.any?
+          records.each { |record| target.delete(record) }
+
+          records.each { |record| callback(:after_remove, record) }
+        end
+
+        # Delete the given records from the association, using one of the methods :destroy,
+        # :delete_all or :nullify (or nil, in which case a default is used).
+        def delete_records(records, method)
+          raise NotImplementedError
+        end
+
+        def replace_records(new_target, original_target)
+          delete(target - new_target)
+
+          unless concat(new_target - target)
+            @target = original_target
+            raise RecordNotSaved, "Failed to replace #{reflection.name} because one or more of the " \
+                                  "new records could not be saved."
+          end
+
+          target
+        end
+
+        def concat_records(records, should_raise = false)
+          result = true
+
+          records.flatten.each do |record|
+            raise_on_type_mismatch!(record)
+            add_to_target(record) do |rec|
+              result &&= insert_record(rec, true, should_raise) unless owner.new_record?
+            end
+          end
+
+          result && records
+        end
+
+        def callback(method, record)
+          callbacks_for(method).each do |callback|
+            callback.call(method, owner, record)
+          end
+        end
+
+        def callbacks_for(callback_name)
+          full_callback_name = "#{callback_name}_for_#{reflection.name}"
+          owner.class.send(full_callback_name)
+        end
+
+        # Should we deal with assoc.first or assoc.last by issuing an independent query to
+        # the database, or by getting the target, and then taking the first/last item from that?
+        #
+        # If the args is just a non-empty options hash, go to the database.
+        #
+        # Otherwise, go to the database only if none of the following are true:
+        #   * target already loaded
+        #   * owner is new record
+        #   * target contains new or changed record(s)
+        def fetch_first_nth_or_last_using_find?(args)
+          if args.first.is_a?(Hash)
+            true
+          else
+            !(loaded? ||
+              owner.new_record? ||
+              target.any? { |record| record.new_record? || record.changed? })
+          end
+        end
+
+        def include_in_memory?(record)
+          if reflection.is_a?(ActiveRecord::Reflection::ThroughReflection)
+            assoc = owner.association(reflection.through_reflection.name)
+            assoc.reader.any? { |source|
+              target = source.send(reflection.source_reflection.name)
+              target.respond_to?(:include?) ? target.include?(record) : target == record
+            } || target.include?(record)
+          else
+            target.include?(record)
+          end
+        end
+
+        # If the :inverse_of option has been
+        # specified, then #find scans the entire collection.
+        def find_by_scan(*args)
+          expects_array = args.first.kind_of?(Array)
+          ids           = args.flatten.compact.map{ |arg| arg.to_s }.uniq
+
+          if ids.size == 1
+            id = ids.first
+            record = load_target.detect { |r| id == r.id.to_s }
+            expects_array ? [ record ] : record
+          else
+            load_target.select { |r| ids.include?(r.id.to_s) }
+          end
+        end
+
+        # Fetches the first/last using SQL if possible, otherwise from the target array.
+        def first_nth_or_last(type, *args)
+          args.shift if args.first.is_a?(Hash) && args.first.empty?
+
+          collection = fetch_first_nth_or_last_using_find?(args) ? scope : load_target
+          collection.send(type, *args).tap do |record|
+            set_inverse_instance record if record.is_a? ActiveRecord::Base
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
new file mode 100644
index 0000000000..84c8cfe72b
--- /dev/null
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -0,0 +1,1030 @@
+module ActiveRecord
+  module Associations
+    # Association proxies in Active Record are middlemen between the object that
+    # holds the association, known as the <tt>@owner</tt>, and the actual associated
+    # object, known as the <tt>@target</tt>. The kind of association any proxy is
+    # about is available in <tt>@reflection</tt>. That's an instance of the class
+    # ActiveRecord::Reflection::AssociationReflection.
+    #
+    # For example, given
+    #
+    #   class Blog < ActiveRecord::Base
+    #     has_many :posts
+    #   end
+    #
+    #   blog = Blog.first
+    #
+    # the association proxy in <tt>blog.posts</tt> has the object in +blog+ as
+    # <tt>@owner</tt>, the collection of its posts as <tt>@target</tt>, and
+    # the <tt>@reflection</tt> object represents a <tt>:has_many</tt> macro.
+    #
+    # This class delegates unknown methods to <tt>@target</tt> via
+    # <tt>method_missing</tt>.
+    #
+    # The <tt>@target</tt> object is not \loaded until needed. For example,
+    #
+    #   blog.posts.count
+    #
+    # is computed directly through SQL and does not trigger by itself the
+    # instantiation of the actual post records.
+    class CollectionProxy < Relation
+      delegate(*(ActiveRecord::Calculations.public_instance_methods - [:count]), to: :scope)
+
+      def initialize(klass, association) #:nodoc:
+        @association = association
+        super klass, klass.arel_table
+        merge! association.scope(nullify: false)
+      end
+
+      def target
+        @association.target
+      end
+
+      def load_target
+        @association.load_target
+      end
+
+      # Returns +true+ if the association has been loaded, otherwise +false+.
+      #
+      #   person.pets.loaded? # => false
+      #   person.pets
+      #   person.pets.loaded? # => true
+      def loaded?
+        @association.loaded?
+      end
+
+      # Works in two ways.
+      #
+      # *First:* Specify a subset of fields to be selected from the result set.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.select(:name)
+      #   # => [
+      #   #      #<Pet id: nil, name: "Fancy-Fancy">,
+      #   #      #<Pet id: nil, name: "Spook">,
+      #   #      #<Pet id: nil, name: "Choo-Choo">
+      #   #    ]
+      #
+      #   person.pets.select(:id, :name )
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy">,
+      #   #      #<Pet id: 2, name: "Spook">,
+      #   #      #<Pet id: 3, name: "Choo-Choo">
+      #   #    ]
+      #
+      # Be careful because this also means you're initializing a model
+      # object with only the fields that you've selected. If you attempt
+      # to access a field except +id+ that is not in the initialized record you'll
+      # receive:
+      #
+      #   person.pets.select(:name).first.person_id
+      #   # => ActiveModel::MissingAttributeError: missing attribute: person_id
+      #
+      # *Second:* You can pass a block so it can be used just like Array#select.
+      # This builds an array of objects from the database for the scope,
+      # converting them into an array and iterating through them using
+      # Array#select.
+      #
+      #   person.pets.select { |pet| pet.name =~ /oo/ }
+      #   # => [
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.select(:name) { |pet| pet.name =~ /oo/ }
+      #   # => [
+      #   #      #<Pet id: 2, name: "Spook">,
+      #   #      #<Pet id: 3, name: "Choo-Choo">
+      #   #    ]
+      def select(*fields, &block)
+        @association.select(*fields, &block)
+      end
+
+      # Finds an object in the collection responding to the +id+. Uses the same
+      # rules as <tt>ActiveRecord::Base.find</tt>. Returns <tt>ActiveRecord::RecordNotFound</tt>
+      # error if the object cannot be found.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.find(1) # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
+      #   person.pets.find(4) # => ActiveRecord::RecordNotFound: Couldn't find Pet with id=4
+      #
+      #   person.pets.find(2) { |pet| pet.name.downcase! }
+      #   # => #<Pet id: 2, name: "fancy-fancy", person_id: 1>
+      #
+      #   person.pets.find(2, 3)
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def find(*args, &block)
+        @association.find(*args, &block)
+      end
+
+      # Returns the first record, or the first +n+ records, from the collection.
+      # If the collection is empty, the first form returns +nil+, and the second
+      # form returns an empty array.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.first # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
+      #
+      #   person.pets.first(2)
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
+      #   #    ]
+      #
+      #   another_person_without.pets          # => []
+      #   another_person_without.pets.first    # => nil
+      #   another_person_without.pets.first(3) # => []
+      def first(*args)
+        @association.first(*args)
+      end
+
+      # Same as +first+ except returns only the second record.
+      def second(*args)
+        @association.second(*args)
+      end
+
+      # Same as +first+ except returns only the third record.
+      def third(*args)
+        @association.third(*args)
+      end
+
+      # Same as +first+ except returns only the fourth record.
+      def fourth(*args)
+        @association.fourth(*args)
+      end
+
+      # Same as +first+ except returns only the fifth record.
+      def fifth(*args)
+        @association.fifth(*args)
+      end
+
+      # Same as +first+ except returns only the forty second record.
+      # Also known as accessing "the reddit".
+      def forty_two(*args)
+        @association.forty_two(*args)
+      end
+
+      # Returns the last record, or the last +n+ records, from the collection.
+      # If the collection is empty, the first form returns +nil+, and the second
+      # form returns an empty array.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.last # => #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #
+      #   person.pets.last(2)
+      #   # => [
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   another_person_without.pets         # => []
+      #   another_person_without.pets.last    # => nil
+      #   another_person_without.pets.last(3) # => []
+      def last(*args)
+        @association.last(*args)
+      end
+
+      # Returns a new object of the collection type that has been instantiated
+      # with +attributes+ and linked to this object, but have not yet been saved.
+      # You can pass an array of attributes hashes, this will return an array
+      # with the new objects.
+      #
+      #   class Person
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.build
+      #   # => #<Pet id: nil, name: nil, person_id: 1>
+      #
+      #   person.pets.build(name: 'Fancy-Fancy')
+      #   # => #<Pet id: nil, name: "Fancy-Fancy", person_id: 1>
+      #
+      #   person.pets.build([{name: 'Spook'}, {name: 'Choo-Choo'}, {name: 'Brain'}])
+      #   # => [
+      #   #      #<Pet id: nil, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: nil, name: "Choo-Choo", person_id: 1>,
+      #   #      #<Pet id: nil, name: "Brain", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size  # => 5 # size of the collection
+      #   person.pets.count # => 0 # count from database
+      def build(attributes = {}, &block)
+        @association.build(attributes, &block)
+      end
+      alias_method :new, :build
+
+      # Returns a new object of the collection type that has been instantiated with
+      # attributes, linked to this object and that has already been saved (if it
+      # passes the validations).
+      #
+      #   class Person
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.create(name: 'Fancy-Fancy')
+      #   # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
+      #
+      #   person.pets.create([{name: 'Spook'}, {name: 'Choo-Choo'}])
+      #   # => [
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size  # => 3
+      #   person.pets.count # => 3
+      #
+      #   person.pets.find(1, 2, 3)
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def create(attributes = {}, &block)
+        @association.create(attributes, &block)
+      end
+
+      # Like +create+, except that if the record is invalid, raises an exception.
+      #
+      #   class Person
+      #     has_many :pets
+      #   end
+      #
+      #   class Pet
+      #     validates :name, presence: true
+      #   end
+      #
+      #   person.pets.create!(name: nil)
+      #   # => ActiveRecord::RecordInvalid: Validation failed: Name can't be blank
+      def create!(attributes = {}, &block)
+        @association.create!(attributes, &block)
+      end
+
+      # Add one or more records to the collection by setting their foreign keys
+      # to the association's primary key. Since << flattens its argument list and
+      # inserts each record, +push+ and +concat+ behave identically. Returns +self+
+      # so method calls may be chained.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 0
+      #   person.pets.concat(Pet.new(name: 'Fancy-Fancy'))
+      #   person.pets.concat(Pet.new(name: 'Spook'), Pet.new(name: 'Choo-Choo'))
+      #   person.pets.size # => 3
+      #
+      #   person.id # => 1
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.concat([Pet.new(name: 'Brain'), Pet.new(name: 'Benny')])
+      #   person.pets.size # => 5
+      def concat(*records)
+        @association.concat(*records)
+      end
+
+      # Replaces this collection with +other_array+. This will perform a diff
+      # and delete/add only records that have changed.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [#<Pet id: 1, name: "Gorby", group: "cats", person_id: 1>]
+      #
+      #   other_pets = [Pet.new(name: 'Puff', group: 'celebrities']
+      #
+      #   person.pets.replace(other_pets)
+      #
+      #   person.pets
+      #   # => [#<Pet id: 2, name: "Puff", group: "celebrities", person_id: 1>]
+      #
+      # If the supplied array has an incorrect association type, it raises
+      # an <tt>ActiveRecord::AssociationTypeMismatch</tt> error:
+      #
+      #   person.pets.replace(["doo", "ggie", "gaga"])
+      #   # => ActiveRecord::AssociationTypeMismatch: Pet expected, got String
+      def replace(other_array)
+        @association.replace(other_array)
+      end
+
+      # Deletes all the records from the collection. For +has_many+ associations,
+      # the deletion is done according to the strategy specified by the <tt>:dependent</tt>
+      # option.
+      #
+      # If no <tt>:dependent</tt> option is given, then it will follow the
+      # default strategy. The default strategy is <tt>:nullify</tt>. This
+      # sets the foreign keys to <tt>NULL</tt>. For, +has_many+ <tt>:through</tt>,
+      # the default strategy is +delete_all+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets # dependent: :nullify option by default
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete_all
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size # => 0
+      #   person.pets      # => []
+      #
+      #   Pet.find(1, 2, 3)
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: nil>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: nil>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: nil>
+      #   #    ]
+      #
+      # If it is set to <tt>:destroy</tt> all the objects from the collection
+      # are removed by calling their +destroy+ method. See +destroy+ for more
+      # information.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets, dependent: :destroy
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete_all
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   Pet.find(1, 2, 3)
+      #   # => ActiveRecord::RecordNotFound
+      #
+      # If it is set to <tt>:delete_all</tt>, all the objects are deleted
+      # *without* calling their +destroy+ method.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets, dependent: :delete_all
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete_all
+      #
+      #   Pet.find(1, 2, 3)
+      #   # => ActiveRecord::RecordNotFound
+      def delete_all(dependent = nil)
+        @association.delete_all(dependent)
+      end
+
+      # Deletes the records of the collection directly from the database
+      # ignoring the +:dependent+ option. It invokes +before_remove+,
+      # +after_remove+ , +before_destroy+ and +after_destroy+ callbacks.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy_all
+      #
+      #   person.pets.size # => 0
+      #   person.pets      # => []
+      #
+      #   Pet.find(1) # => Couldn't find Pet with id=1
+      def destroy_all
+        @association.destroy_all
+      end
+
+      # Deletes the +records+ supplied and removes them from the collection. For
+      # +has_many+ associations, the deletion is done according to the strategy
+      # specified by the <tt>:dependent</tt> option. Returns an array with the
+      # deleted records.
+      #
+      # If no <tt>:dependent</tt> option is given, then it will follow the default
+      # strategy. The default strategy is <tt>:nullify</tt>. This sets the foreign
+      # keys to <tt>NULL</tt>. For, +has_many+ <tt>:through</tt>, the default
+      # strategy is +delete_all+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets # dependent: :nullify option by default
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete(Pet.find(1))
+      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
+      #
+      #   person.pets.size # => 2
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   Pet.find(1)
+      #   # => #<Pet id: 1, name: "Fancy-Fancy", person_id: nil>
+      #
+      # If it is set to <tt>:destroy</tt> all the +records+ are removed by calling
+      # their +destroy+ method. See +destroy+ for more information.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets, dependent: :destroy
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete(Pet.find(1), Pet.find(3))
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size # => 1
+      #   person.pets
+      #   # => [#<Pet id: 2, name: "Spook", person_id: 1>]
+      #
+      #   Pet.find(1, 3)
+      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with IDs (1, 3)
+      #
+      # If it is set to <tt>:delete_all</tt>, all the +records+ are deleted
+      # *without* calling their +destroy+ method.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets, dependent: :delete_all
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete(Pet.find(1))
+      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
+      #
+      #   person.pets.size # => 2
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   Pet.find(1)
+      #   # => ActiveRecord::RecordNotFound: Couldn't find Pet with id=1
+      #
+      # You can pass +Fixnum+ or +String+ values, it finds the records
+      # responding to the +id+ and executes delete on them.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.delete("1")
+      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
+      #
+      #   person.pets.delete(2, 3)
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def delete(*records)
+        @association.delete(*records)
+      end
+
+      # Destroys the +records+ supplied and removes them from the collection.
+      # This method will _always_ remove record from the database ignoring
+      # the +:dependent+ option. Returns an array with the removed records.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy(Pet.find(1))
+      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
+      #
+      #   person.pets.size # => 2
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy(Pet.find(2), Pet.find(3))
+      #   # => [
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size  # => 0
+      #   person.pets       # => []
+      #
+      #   Pet.find(1, 2, 3) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with IDs (1, 2, 3)
+      #
+      # You can pass +Fixnum+ or +String+ values, it finds the records
+      # responding to the +id+ and then deletes them from the database.
+      #
+      #   person.pets.size # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy("4")
+      #   # => #<Pet id: 4, name: "Benny", person_id: 1>
+      #
+      #   person.pets.size # => 2
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.destroy(5, 6)
+      #   # => [
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size  # => 0
+      #   person.pets       # => []
+      #
+      #   Pet.find(4, 5, 6) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with IDs (4, 5, 6)
+      def destroy(*records)
+        @association.destroy(*records)
+      end
+
+      # Specifies whether the records should be unique or not.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.select(:name)
+      #   # => [
+      #   #      #<Pet name: "Fancy-Fancy">,
+      #   #      #<Pet name: "Fancy-Fancy">
+      #   #    ]
+      #
+      #   person.pets.select(:name).distinct
+      #   # => [#<Pet name: "Fancy-Fancy">]
+      def distinct
+        @association.distinct
+      end
+      alias uniq distinct
+
+      # Count all records using SQL.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.count # => 3
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def count(column_name = nil, options = {})
+        # TODO: Remove options argument as soon we remove support to
+        # activerecord-deprecated_finders.
+        @association.count(column_name, options)
+      end
+
+      # Returns the size of the collection. If the collection hasn't been loaded,
+      # it executes a <tt>SELECT COUNT(*)</tt> query. Else it calls <tt>collection.size</tt>.
+      #
+      # If the collection has been already loaded +size+ and +length+ are
+      # equivalent. If not and you are going to need the records anyway
+      # +length+ will take one less query. Otherwise +size+ is more efficient.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 3
+      #   # executes something like SELECT COUNT(*) FROM "pets" WHERE "pets"."person_id" = 1
+      #
+      #   person.pets # This will execute a SELECT * FROM query
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      #
+      #   person.pets.size # => 3
+      #   # Because the collection is already loaded, this will behave like
+      #   # collection.size and no SQL count query is executed.
+      def size
+        @association.size
+      end
+
+      # Returns the size of the collection calling +size+ on the target.
+      # If the collection has been already loaded, +length+ and +size+ are
+      # equivalent. If not and you are going to need the records anyway this
+      # method will take one less query. Otherwise +size+ is more efficient.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.length # => 3
+      #   # executes something like SELECT "pets".* FROM "pets" WHERE "pets"."person_id" = 1
+      #
+      #   # Because the collection is loaded, you can
+      #   # call the collection with no additional queries:
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def length
+        @association.length
+      end
+
+      # Returns +true+ if the collection is empty. If the collection has been
+      # loaded it is equivalent
+      # to <tt>collection.size.zero?</tt>. If the collection has not been loaded,
+      # it is equivalent to <tt>collection.exists?</tt>. If the collection has
+      # not already been loaded and you are going to fetch the records anyway it
+      # is better to check <tt>collection.length.zero?</tt>.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.count  # => 1
+      #   person.pets.empty? # => false
+      #
+      #   person.pets.delete_all
+      #
+      #   person.pets.count  # => 0
+      #   person.pets.empty? # => true
+      def empty?
+        @association.empty?
+      end
+
+      # Returns +true+ if the collection is not empty.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.count # => 0
+      #   person.pets.any?  # => false
+      #
+      #   person.pets << Pet.new(name: 'Snoop')
+      #   person.pets.count # => 0
+      #   person.pets.any?  # => true
+      #
+      # You can also pass a block to define criteria. The behavior
+      # is the same, it returns true if the collection based on the
+      # criteria is not empty.
+      #
+      #   person.pets
+      #   # => [#<Pet name: "Snoop", group: "dogs">]
+      #
+      #   person.pets.any? do |pet|
+      #     pet.group == 'cats'
+      #   end
+      #   # => false
+      #
+      #   person.pets.any? do |pet|
+      #     pet.group == 'dogs'
+      #   end
+      #   # => true
+      def any?(&block)
+        @association.any?(&block)
+      end
+
+      # Returns true if the collection has more than one record.
+      # Equivalent to <tt>collection.size > 1</tt>.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.count # => 1
+      #   person.pets.many? # => false
+      #
+      #   person.pets << Pet.new(name: 'Snoopy')
+      #   person.pets.count # => 2
+      #   person.pets.many? # => true
+      #
+      # You can also pass a block to define criteria. The
+      # behavior is the same, it returns true if the collection
+      # based on the criteria has more than one record.
+      #
+      #   person.pets
+      #   # => [
+      #   #      #<Pet name: "Gorby", group: "cats">,
+      #   #      #<Pet name: "Puff", group: "cats">,
+      #   #      #<Pet name: "Snoop", group: "dogs">
+      #   #    ]
+      #
+      #   person.pets.many? do |pet|
+      #     pet.group == 'dogs'
+      #   end
+      #   # => false
+      #
+      #   person.pets.many? do |pet|
+      #     pet.group == 'cats'
+      #   end
+      #   # => true
+      def many?(&block)
+        @association.many?(&block)
+      end
+
+      # Returns +true+ if the given object is present in the collection.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets # => [#<Pet id: 20, name: "Snoop">]
+      #
+      #   person.pets.include?(Pet.find(20)) # => true
+      #   person.pets.include?(Pet.find(21)) # => false
+      def include?(record)
+        !!@association.include?(record)
+      end
+
+      def arel
+        scope.arel
+      end
+
+      def proxy_association
+        @association
+      end
+
+      # We don't want this object to be put on the scoping stack, because
+      # that could create an infinite loop where we call an @association
+      # method, which gets the current scope, which is this object, which
+      # delegates to @association, and so on.
+      def scoping
+        @association.scope.scoping { yield }
+      end
+
+      # Returns a <tt>Relation</tt> object for the records in this association
+      def scope
+        @association.scope
+      end
+      alias spawn scope
+
+      # Equivalent to <tt>Array#==</tt>. Returns +true+ if the two arrays
+      # contain the same number of elements and if each element is equal
+      # to the corresponding element in the other array, otherwise returns
+      # +false+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
+      #   #    ]
+      #
+      #   other = person.pets.to_ary
+      #
+      #   person.pets == other
+      #   # => true
+      #
+      #   other = [Pet.new(id: 1), Pet.new(id: 2)]
+      #
+      #   person.pets == other
+      #   # => false
+      def ==(other)
+        load_target == other
+      end
+
+      # Returns a new array of objects from the collection. If the collection
+      # hasn't been loaded, it fetches the records from the database.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets
+      #   # => [
+      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   other_pets = person.pets.to_ary
+      #   # => [
+      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      #
+      #   other_pets.replace([Pet.new(name: 'BooGoo')])
+      #
+      #   other_pets
+      #   # => [#<Pet id: nil, name: "BooGoo", person_id: 1>]
+      #
+      #   person.pets
+      #   # This is not affected by replace
+      #   # => [
+      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
+      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
+      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
+      #   #    ]
+      def to_ary
+        load_target.dup
+      end
+      alias_method :to_a, :to_ary
+
+      # Adds one or more +records+ to the collection by setting their foreign keys
+      # to the association's primary key. Returns +self+, so several appends may be
+      # chained together.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets.size # => 0
+      #   person.pets << Pet.new(name: 'Fancy-Fancy')
+      #   person.pets << [Pet.new(name: 'Spook'), Pet.new(name: 'Choo-Choo')]
+      #   person.pets.size # => 3
+      #
+      #   person.id # => 1
+      #   person.pets
+      #   # => [
+      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
+      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
+      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
+      #   #    ]
+      def <<(*records)
+        proxy_association.concat(records) && self
+      end
+      alias_method :push, :<<
+      alias_method :append, :<<
+
+      def prepend(*args)
+        raise NoMethodError, "prepend on association is not defined. Please use << or append"
+      end
+
+      # Equivalent to +delete_all+. The difference is that returns +self+, instead
+      # of an array with the deleted objects, so methods can be chained. See
+      # +delete_all+ for more information.
+      def clear
+        delete_all
+        self
+      end
+
+      # Reloads the collection from the database. Returns +self+.
+      # Equivalent to <tt>collection(true)</tt>.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets # uses the pets cache
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets.reload # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets(true)  # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      def reload
+        proxy_association.reload
+        self
+      end
+
+      # Unloads the association. Returns +self+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets # uses the pets cache
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets.reset # clears the pets cache
+      #
+      #   person.pets  # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      def reset
+        proxy_association.reset
+        proxy_association.reset_scope
+        self
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
new file mode 100644
index 0000000000..79c3d2b0f5
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -0,0 +1,184 @@
+module ActiveRecord
+  # = Active Record Has Many Association
+  module Associations
+    # This is the proxy that handles a has many association.
+    #
+    # If the association has a <tt>:through</tt> option further specialization
+    # is provided by its child HasManyThroughAssociation.
+    class HasManyAssociation < CollectionAssociation #:nodoc:
+
+      def handle_dependency
+        case options[:dependent]
+        when :restrict_with_exception
+          raise ActiveRecord::DeleteRestrictionError.new(reflection.name) unless empty?
+
+        when :restrict_with_error
+          unless empty?
+            record = klass.human_attribute_name(reflection.name).downcase
+            owner.errors.add(:base, :"restrict_dependent_destroy.many", record: record)
+            false
+          end
+
+        else
+          if options[:dependent] == :destroy
+            # No point in executing the counter update since we're going to destroy the parent anyway
+            load_target.each { |t| t.destroyed_by_association = reflection }
+            destroy_all
+          else
+            delete_all
+          end
+        end
+      end
+
+      def insert_record(record, validate = true, raise = false)
+        set_owner_attributes(record)
+        set_inverse_instance(record)
+
+        if raise
+          record.save!(:validate => validate)
+        else
+          record.save(:validate => validate)
+        end
+      end
+
+      def empty?
+        if has_cached_counter?
+          size.zero?
+        else
+          super
+        end
+      end
+
+      private
+
+        # Returns the number of records in this collection.
+        #
+        # If the association has a counter cache it gets that value. Otherwise
+        # it will attempt to do a count via SQL, bounded to <tt>:limit</tt> if
+        # there's one. Some configuration options like :group make it impossible
+        # to do an SQL count, in those cases the array count will be used.
+        #
+        # That does not depend on whether the collection has already been loaded
+        # or not. The +size+ method is the one that takes the loaded flag into
+        # account and delegates to +count_records+ if needed.
+        #
+        # If the collection is empty the target is set to an empty array and
+        # the loaded flag is set to true as well.
+        def count_records
+          count = if has_cached_counter?
+            owner.read_attribute cached_counter_attribute_name
+          else
+            scope.count
+          end
+
+          # If there's nothing in the database and @target has no new records
+          # we are certain the current target is an empty array. This is a
+          # documented side-effect of the method that may avoid an extra SELECT.
+          @target ||= [] and loaded! if count == 0
+
+          [association_scope.limit_value, count].compact.min
+        end
+
+        def has_cached_counter?(reflection = reflection())
+          owner.attribute_present?(cached_counter_attribute_name(reflection))
+        end
+
+        def cached_counter_attribute_name(reflection = reflection())
+          options[:counter_cache] || "#{reflection.name}_count"
+        end
+
+        def update_counter(difference, reflection = reflection())
+          update_counter_in_database(difference, reflection)
+          update_counter_in_memory(difference, reflection)
+        end
+
+        def update_counter_in_database(difference, reflection = reflection())
+          if has_cached_counter?(reflection)
+            counter = cached_counter_attribute_name(reflection)
+            owner.class.update_counters(owner.id, counter => difference)
+          end
+        end
+
+        def update_counter_in_memory(difference, reflection = reflection())
+          if has_cached_counter?(reflection)
+            counter = cached_counter_attribute_name(reflection)
+            owner[counter] += difference
+            owner.changed_attributes.delete(counter) # eww
+          end
+        end
+
+        # This shit is nasty. We need to avoid the following situation:
+        #
+        #   * An associated record is deleted via record.destroy
+        #   * Hence the callbacks run, and they find a belongs_to on the record with a
+        #     :counter_cache options which points back at our owner. So they update the
+        #     counter cache.
+        #   * In which case, we must make sure to *not* update the counter cache, or else
+        #     it will be decremented twice.
+        #
+        # Hence this method.
+        def inverse_updates_counter_cache?(reflection = reflection())
+          counter_name = cached_counter_attribute_name(reflection)
+          inverse_updates_counter_named?(counter_name, reflection)
+        end
+
+        def inverse_updates_counter_named?(counter_name, reflection = reflection())
+          reflection.klass._reflections.values.any? { |inverse_reflection|
+            inverse_reflection.belongs_to? &&
+            inverse_reflection.counter_cache_column == counter_name
+          }
+        end
+
+        def delete_count(method, scope)
+          if method == :delete_all
+            scope.delete_all
+          else
+            scope.update_all(reflection.foreign_key => nil)
+          end
+        end
+
+        def delete_or_nullify_all_records(method)
+          count = delete_count(method, self.scope)
+          update_counter(-count)
+        end
+
+        # Deletes the records according to the <tt>:dependent</tt> option.
+        def delete_records(records, method)
+          if method == :destroy
+            records.each(&:destroy!)
+            update_counter(-records.length) unless inverse_updates_counter_cache?
+          else
+            scope = self.scope.where(reflection.klass.primary_key => records)
+            update_counter(-delete_count(method, scope))
+          end
+        end
+
+        def foreign_key_present?
+          if reflection.klass.primary_key
+            owner.attribute_present?(reflection.association_primary_key)
+          else
+            false
+          end
+        end
+
+        def concat_records(records, *)
+          update_counter_if_success(super, records.length)
+        end
+
+        def _create_record(attributes, *)
+          if attributes.is_a?(Array)
+            super
+          else
+            update_counter_if_success(super, 1)
+          end
+        end
+
+        def update_counter_if_success(saved_successfully, difference)
+          if saved_successfully
+            update_counter_in_memory(difference)
+          end
+          saved_successfully
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
new file mode 100644
index 0000000000..44c4436e95
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -0,0 +1,235 @@
+module ActiveRecord
+  # = Active Record Has Many Through Association
+  module Associations
+    class HasManyThroughAssociation < HasManyAssociation #:nodoc:
+      include ThroughAssociation
+
+      def initialize(owner, reflection)
+        super
+
+        @through_records     = {}
+        @through_association = nil
+      end
+
+      # Returns the size of the collection by executing a SELECT COUNT(*) query
+      # if the collection hasn't been loaded, and by calling collection.size if
+      # it has. If the collection will likely have a size greater than zero,
+      # and if fetching the collection will be needed afterwards, one less
+      # SELECT query will be generated by using #length instead.
+      def size
+        if has_cached_counter?
+          owner.read_attribute cached_counter_attribute_name(reflection)
+        elsif loaded?
+          target.size
+        else
+          super
+        end
+      end
+
+      def concat(*records)
+        unless owner.new_record?
+          records.flatten.each do |record|
+            raise_on_type_mismatch!(record)
+          end
+        end
+
+        super
+      end
+
+      def concat_records(records)
+        ensure_not_nested
+
+        records = super(records, true)
+
+        if owner.new_record? && records
+          records.flatten.each do |record|
+            build_through_record(record)
+          end
+        end
+
+        records
+      end
+
+      def insert_record(record, validate = true, raise = false)
+        ensure_not_nested
+
+        if record.new_record?
+          if raise
+            record.save!(:validate => validate)
+          else
+            return unless record.save(:validate => validate)
+          end
+        end
+
+        save_through_record(record)
+        if has_cached_counter? && !through_reflection_updates_counter_cache?
+          ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
+            Automatic updating of counter caches on through associations has been
+            deprecated, and will be removed in Rails 5.0. Instead, please set the
+            appropriate counter_cache options on the has_many and belongs_to for
+            your associations to #{through_reflection.name}.
+          MESSAGE
+          update_counter_in_database(1)
+        end
+        record
+      end
+
+      private
+
+        def through_association
+          @through_association ||= owner.association(through_reflection.name)
+        end
+
+        # The through record (built with build_record) is temporarily cached
+        # so that it may be reused if insert_record is subsequently called.
+        #
+        # However, after insert_record has been called, the cache is cleared in
+        # order to allow multiple instances of the same record in an association.
+        def build_through_record(record)
+          @through_records[record.object_id] ||= begin
+            ensure_mutable
+
+            through_record = through_association.build(*options_for_through_record)
+            through_record.send("#{source_reflection.name}=", record)
+            through_record
+          end
+        end
+
+        def options_for_through_record
+          [through_scope_attributes]
+        end
+
+        def through_scope_attributes
+          scope.where_values_hash(through_association.reflection.name.to_s).
+            except!(through_association.reflection.foreign_key,
+                    through_association.reflection.klass.inheritance_column)
+        end
+
+        def save_through_record(record)
+          build_through_record(record).save!
+        ensure
+          @through_records.delete(record.object_id)
+        end
+
+        def build_record(attributes)
+          ensure_not_nested
+
+          record = super(attributes)
+
+          inverse = source_reflection.inverse_of
+          if inverse
+            if inverse.collection?
+              record.send(inverse.name) << build_through_record(record)
+            elsif inverse.has_one?
+              record.send("#{inverse.name}=", build_through_record(record))
+            end
+          end
+
+          record
+        end
+
+        def target_reflection_has_associated_record?
+          !(through_reflection.belongs_to? && owner[through_reflection.foreign_key].blank?)
+        end
+
+        def update_through_counter?(method)
+          case method
+          when :destroy
+            !inverse_updates_counter_cache?(through_reflection)
+          when :nullify
+            false
+          else
+            true
+          end
+        end
+
+        def delete_or_nullify_all_records(method)
+          delete_records(load_target, method)
+        end
+
+        def delete_records(records, method)
+          ensure_not_nested
+
+          scope = through_association.scope
+          scope.where! construct_join_attributes(*records)
+
+          case method
+          when :destroy
+            if scope.klass.primary_key
+              count = scope.destroy_all.length
+            else
+              scope.to_a.each do |record|
+                record.run_callbacks :destroy
+              end
+
+              arel = scope.arel
+
+              stmt = Arel::DeleteManager.new arel.engine
+              stmt.from scope.klass.arel_table
+              stmt.wheres = arel.constraints
+
+              count = scope.klass.connection.delete(stmt, 'SQL', scope.bind_values)
+            end
+          when :nullify
+            count = scope.update_all(source_reflection.foreign_key => nil)
+          else
+            count = scope.delete_all
+          end
+
+          delete_through_records(records)
+
+          if source_reflection.options[:counter_cache] && method != :destroy
+            counter = source_reflection.counter_cache_column
+            klass.decrement_counter counter, records.map(&:id)
+          end
+
+          if through_reflection.collection? && update_through_counter?(method)
+            update_counter(-count, through_reflection)
+          end
+
+          update_counter(-count)
+        end
+
+        def through_records_for(record)
+          attributes = construct_join_attributes(record)
+          candidates = Array.wrap(through_association.target)
+          candidates.find_all do |c|
+            attributes.all? do |key, value|
+              c.public_send(key) == value
+            end
+          end
+        end
+
+        def delete_through_records(records)
+          records.each do |record|
+            through_records = through_records_for(record)
+
+            if through_reflection.collection?
+              through_records.each { |r| through_association.target.delete(r) }
+            else
+              if through_records.include?(through_association.target)
+                through_association.target = nil
+              end
+            end
+
+            @through_records.delete(record.object_id)
+          end
+        end
+
+        def find_target
+          return [] unless target_reflection_has_associated_record?
+          get_records
+        end
+
+        # NOTE - not sure that we can actually cope with inverses here
+        def invertible_for?(record)
+          false
+        end
+
+        def through_reflection_updates_counter_cache?
+          counter_name = cached_counter_attribute_name
+          inverse_updates_counter_named?(counter_name, through_reflection)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
new file mode 100644
index 0000000000..e6095d84dc
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -0,0 +1,105 @@
+module ActiveRecord
+  # = Active Record Belongs To Has One Association
+  module Associations
+    class HasOneAssociation < SingularAssociation #:nodoc:
+
+      def handle_dependency
+        case options[:dependent]
+        when :restrict_with_exception
+          raise ActiveRecord::DeleteRestrictionError.new(reflection.name) if load_target
+
+        when :restrict_with_error
+          if load_target
+            record = klass.human_attribute_name(reflection.name).downcase
+            owner.errors.add(:base, :"restrict_dependent_destroy.one", record: record)
+            false
+          end
+
+        else
+          delete
+        end
+      end
+
+      def replace(record, save = true)
+        raise_on_type_mismatch!(record) if record
+        load_target
+
+        return self.target if !(target || record)
+
+        assigning_another_record = target != record
+        if assigning_another_record || record.changed?
+          save &&= owner.persisted?
+
+          transaction_if(save) do
+            remove_target!(options[:dependent]) if target && !target.destroyed? && assigning_another_record
+
+            if record
+              set_owner_attributes(record)
+              set_inverse_instance(record)
+
+              if save && !record.save
+                nullify_owner_attributes(record)
+                set_owner_attributes(target) if target
+                raise RecordNotSaved, "Failed to save the new associated #{reflection.name}."
+              end
+            end
+          end
+        end
+
+        self.target = record
+      end
+
+      def delete(method = options[:dependent])
+        if load_target
+          case method
+            when :delete
+              target.delete
+            when :destroy
+              target.destroy
+            when :nullify
+              target.update_columns(reflection.foreign_key => nil)
+          end
+        end
+      end
+
+      private
+
+        # The reason that the save param for replace is false, if for create (not just build),
+        # is because the setting of the foreign keys is actually handled by the scoping when
+        # the record is instantiated, and so they are set straight away and do not need to be
+        # updated within replace.
+        def set_new_record(record)
+          replace(record, false)
+        end
+
+        def remove_target!(method)
+          case method
+            when :delete
+              target.delete
+            when :destroy
+              target.destroy
+            else
+              nullify_owner_attributes(target)
+
+              if target.persisted? && owner.persisted? && !target.save
+                set_owner_attributes(target)
+                raise RecordNotSaved, "Failed to remove the existing associated #{reflection.name}. " +
+                                      "The record failed to save after its foreign key was set to nil."
+              end
+          end
+        end
+
+        def nullify_owner_attributes(record)
+          record[reflection.foreign_key] = nil
+        end
+
+        def transaction_if(value)
+          if value
+            reflection.klass.transaction { yield }
+          else
+            yield
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_one_through_association.rb b/activerecord/lib/active_record/associations/has_one_through_association.rb
new file mode 100644
index 0000000000..08e0ec691f
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_one_through_association.rb
@@ -0,0 +1,36 @@
+module ActiveRecord
+  # = Active Record Has One Through Association
+  module Associations
+    class HasOneThroughAssociation < HasOneAssociation #:nodoc:
+      include ThroughAssociation
+
+      def replace(record)
+        create_through_record(record)
+        self.target = record
+      end
+
+      private
+
+        def create_through_record(record)
+          ensure_not_nested
+
+          through_proxy  = owner.association(through_reflection.name)
+          through_record = through_proxy.send(:load_target)
+
+          if through_record && !record
+            through_record.destroy
+          elsif record
+            attributes = construct_join_attributes(record)
+
+            if through_record
+              through_record.update(attributes)
+            elsif owner.new_record?
+              through_proxy.build(attributes)
+            else
+              through_proxy.create(attributes)
+            end
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb
new file mode 100644
index 0000000000..ec5c189cd3
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -0,0 +1,273 @@
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      autoload :JoinBase,        'active_record/associations/join_dependency/join_base'
+      autoload :JoinAssociation, 'active_record/associations/join_dependency/join_association'
+
+      class Aliases # :nodoc:
+        def initialize(tables)
+          @tables = tables
+          @alias_cache = tables.each_with_object({}) { |table,h|
+            h[table.node] = table.columns.each_with_object({}) { |column,i|
+              i[column.name] = column.alias
+            }
+          }
+          @name_and_alias_cache = tables.each_with_object({}) { |table,h|
+            h[table.node] = table.columns.map { |column|
+              [column.name, column.alias]
+            }
+          }
+        end
+
+        def columns
+          @tables.flat_map { |t| t.column_aliases }
+        end
+
+        # An array of [column_name, alias] pairs for the table
+        def column_aliases(node)
+          @name_and_alias_cache[node]
+        end
+
+        def column_alias(node, column)
+          @alias_cache[node][column]
+        end
+
+        class Table < Struct.new(:node, :columns)
+          def table
+            Arel::Nodes::TableAlias.new node.table, node.aliased_table_name
+          end
+
+          def column_aliases
+            t = table
+            columns.map { |column| t[column.name].as Arel.sql column.alias }
+          end
+        end
+        Column = Struct.new(:name, :alias)
+      end
+
+      attr_reader :alias_tracker, :base_klass, :join_root
+
+      def self.make_tree(associations)
+        hash = {}
+        walk_tree associations, hash
+        hash
+      end
+
+      def self.walk_tree(associations, hash)
+        case associations
+        when Symbol, String
+          hash[associations.to_sym] ||= {}
+        when Array
+          associations.each do |assoc|
+            walk_tree assoc, hash
+          end
+        when Hash
+          associations.each do |k,v|
+            cache = hash[k] ||= {}
+            walk_tree v, cache
+          end
+        else
+          raise ConfigurationError, associations.inspect
+        end
+      end
+
+      # base is the base class on which operation is taking place.
+      # associations is the list of associations which are joined using hash, symbol or array.
+      # joins is the list of all string join commands and arel nodes.
+      #
+      #  Example :
+      #
+      #  class Physician < ActiveRecord::Base
+      #    has_many :appointments
+      #    has_many :patients, through: :appointments
+      #  end
+      #
+      #  If I execute `@physician.patients.to_a` then
+      #    base # => Physician
+      #    associations # => []
+      #    joins # =>  [#<Arel::Nodes::InnerJoin: ...]
+      #
+      #  However if I execute `Physician.joins(:appointments).to_a` then
+      #    base # => Physician
+      #    associations # => [:appointments]
+      #    joins # =>  []
+      #
+      def initialize(base, associations, joins)
+        @alias_tracker = AliasTracker.create(base.connection, joins)
+        @alias_tracker.aliased_name_for(base.table_name, base.table_name) # Updates the count for base.table_name to 1
+        tree = self.class.make_tree associations
+        @join_root = JoinBase.new base, build(tree, base)
+        @join_root.children.each { |child| construct_tables! @join_root, child }
+      end
+
+      def reflections
+        join_root.drop(1).map!(&:reflection)
+      end
+
+      def join_constraints(outer_joins)
+        joins = join_root.children.flat_map { |child|
+          make_inner_joins join_root, child
+        }
+
+        joins.concat outer_joins.flat_map { |oj|
+          if join_root.match? oj.join_root
+            walk join_root, oj.join_root
+          else
+            oj.join_root.children.flat_map { |child|
+              make_outer_joins oj.join_root, child
+            }
+          end
+        }
+      end
+
+      def aliases
+        Aliases.new join_root.each_with_index.map { |join_part,i|
+          columns = join_part.column_names.each_with_index.map { |column_name,j|
+            Aliases::Column.new column_name, "t#{i}_r#{j}"
+          }
+          Aliases::Table.new(join_part, columns)
+        }
+      end
+
+      def instantiate(result_set, aliases)
+        primary_key = aliases.column_alias(join_root, join_root.primary_key)
+
+        seen = Hash.new { |h,parent_klass|
+          h[parent_klass] = Hash.new { |i,parent_id|
+            i[parent_id] = Hash.new { |j,child_klass| j[child_klass] = {} }
+          }
+        }
+
+        model_cache = Hash.new { |h,klass| h[klass] = {} }
+        parents = model_cache[join_root]
+        column_aliases = aliases.column_aliases join_root
+
+        result_set.each { |row_hash|
+          parent = parents[row_hash[primary_key]] ||= join_root.instantiate(row_hash, column_aliases)
+          construct(parent, join_root, row_hash, result_set, seen, model_cache, aliases)
+        }
+
+        parents.values
+      end
+
+      private
+
+      def make_constraints(parent, child, tables, join_type)
+        chain         = child.reflection.chain
+        foreign_table = parent.table
+        foreign_klass = parent.base_klass
+        child.join_constraints(foreign_table, foreign_klass, child, join_type, tables, child.reflection.scope_chain, chain)
+      end
+
+      def make_outer_joins(parent, child)
+        tables    = table_aliases_for(parent, child)
+        join_type = Arel::Nodes::OuterJoin
+        info      = make_constraints parent, child, tables, join_type
+
+        [info] + child.children.flat_map { |c| make_outer_joins(child, c) }
+      end
+
+      def make_inner_joins(parent, child)
+        tables    = child.tables
+        join_type = Arel::Nodes::InnerJoin
+        info      = make_constraints parent, child, tables, join_type
+
+        [info] + child.children.flat_map { |c| make_inner_joins(child, c) }
+      end
+
+      def table_aliases_for(parent, node)
+        node.reflection.chain.map { |reflection|
+          alias_tracker.aliased_table_for(
+            reflection.table_name,
+            table_alias_for(reflection, parent, reflection != node.reflection)
+          )
+        }
+      end
+
+      def construct_tables!(parent, node)
+        node.tables = table_aliases_for(parent, node)
+        node.children.each { |child| construct_tables! node, child }
+      end
+
+      def table_alias_for(reflection, parent, join)
+        name = "#{reflection.plural_name}_#{parent.table_name}"
+        name << "_join" if join
+        name
+      end
+
+      def walk(left, right)
+        intersection, missing = right.children.map { |node1|
+          [left.children.find { |node2| node1.match? node2 }, node1]
+        }.partition(&:first)
+
+        ojs = missing.flat_map { |_,n| make_outer_joins left, n }
+        intersection.flat_map { |l,r| walk l, r }.concat ojs
+      end
+
+      def find_reflection(klass, name)
+        klass._reflect_on_association(name) or
+          raise ConfigurationError, "Association named '#{ name }' was not found on #{ klass.name }; perhaps you misspelled it?"
+      end
+
+      def build(associations, base_klass)
+        associations.map do |name, right|
+          reflection = find_reflection base_klass, name
+          reflection.check_validity!
+          reflection.check_eager_loadable!
+
+          if reflection.polymorphic?
+            raise EagerLoadPolymorphicError.new(reflection)
+          end
+
+          JoinAssociation.new reflection, build(right, reflection.klass)
+        end
+      end
+
+      def construct(ar_parent, parent, row, rs, seen, model_cache, aliases)
+        primary_id  = ar_parent.id
+
+        parent.children.each do |node|
+          if node.reflection.collection?
+            other = ar_parent.association(node.reflection.name)
+            other.loaded!
+          else
+            if ar_parent.association_cache.key?(node.reflection.name)
+              model = ar_parent.association(node.reflection.name).target
+              construct(model, node, row, rs, seen, model_cache, aliases)
+              next
+            end
+          end
+
+          key = aliases.column_alias(node, node.primary_key)
+          id = row[key]
+          next if id.nil?
+
+          model = seen[parent.base_klass][primary_id][node.base_klass][id]
+
+          if model
+            construct(model, node, row, rs, seen, model_cache, aliases)
+          else
+            model = construct_model(ar_parent, node, row, model_cache, id, aliases)
+            seen[parent.base_klass][primary_id][node.base_klass][id] = model
+            construct(model, node, row, rs, seen, model_cache, aliases)
+          end
+        end
+      end
+
+      def construct_model(record, node, row, model_cache, id, aliases)
+        model = model_cache[node][id] ||= node.instantiate(row,
+                                                           aliases.column_aliases(node))
+        other = record.association(node.reflection.name)
+
+        if node.reflection.collection?
+          other.target.push(model)
+        else
+          other.target = model
+        end
+
+        other.set_inverse_instance(model)
+        model
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
new file mode 100644
index 0000000000..c3bbdccad8
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
@@ -0,0 +1,122 @@
+require 'active_record/associations/join_dependency/join_part'
+
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      class JoinAssociation < JoinPart # :nodoc:
+        # The reflection of the association represented
+        attr_reader :reflection
+
+        attr_accessor :tables
+
+        def initialize(reflection, children)
+          super(reflection.klass, children)
+
+          @reflection      = reflection
+          @tables          = nil
+        end
+
+        def match?(other)
+          return true if self == other
+          super && reflection == other.reflection
+        end
+
+        JoinInformation = Struct.new :joins, :binds
+
+        def join_constraints(foreign_table, foreign_klass, node, join_type, tables, scope_chain, chain)
+          joins         = []
+          bind_values   = []
+          tables        = tables.reverse
+
+          scope_chain_index = 0
+          scope_chain = scope_chain.reverse
+
+          # The chain starts with the target table, but we want to end with it here (makes
+          # more sense in this context), so we reverse
+          chain.reverse_each do |reflection|
+            table = tables.shift
+            klass = reflection.klass
+
+            join_keys   = reflection.join_keys(klass)
+            key         = join_keys.key
+            foreign_key = join_keys.foreign_key
+
+            constraint = build_constraint(klass, table, key, foreign_table, foreign_key)
+
+            scope_chain_items = scope_chain[scope_chain_index].map do |item|
+              if item.is_a?(Relation)
+                item
+              else
+                ActiveRecord::Relation.create(klass, table).instance_exec(node, &item)
+              end
+            end
+            scope_chain_index += 1
+
+            scope_chain_items.concat [klass.send(:build_default_scope, ActiveRecord::Relation.create(klass, table))].compact
+
+            rel = scope_chain_items.inject(scope_chain_items.shift) do |left, right|
+              left.merge right
+            end
+
+            if rel && !rel.arel.constraints.empty?
+              bind_values.concat rel.bind_values
+              constraint = constraint.and rel.arel.constraints
+            end
+
+            if reflection.type
+              value = foreign_klass.base_class.name
+              column = klass.columns_hash[column.to_s]
+
+              substitute = klass.connection.substitute_at(column, bind_values.length)
+              bind_values.push [column, value]
+              constraint = constraint.and table[reflection.type].eq substitute
+            end
+
+            joins << table.create_join(table, table.create_on(constraint), join_type)
+
+            # The current table in this iteration becomes the foreign table in the next
+            foreign_table, foreign_klass = table, klass
+          end
+
+          JoinInformation.new joins, bind_values
+        end
+
+        #  Builds equality condition.
+        #
+        #  Example:
+        #
+        #  class Physician < ActiveRecord::Base
+        #    has_many :appointments
+        #  end
+        #
+        #  If I execute `Physician.joins(:appointments).to_a` then
+        #    klass         # => Physician
+        #    table         # => #<Arel::Table @name="appointments" ...>
+        #    key           # =>  physician_id
+        #    foreign_table # => #<Arel::Table @name="physicians" ...>
+        #    foreign_key   # => id
+        #
+        def build_constraint(klass, table, key, foreign_table, foreign_key)
+          constraint = table[key].eq(foreign_table[foreign_key])
+
+          if klass.finder_needs_type_condition?
+            constraint = table.create_and([
+              constraint,
+              klass.send(:type_condition, table)
+            ])
+          end
+
+          constraint
+        end
+
+        def table
+          tables.first
+        end
+
+        def aliased_table_name
+          table.table_alias || table.name
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_base.rb b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
new file mode 100644
index 0000000000..3a26c25737
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
@@ -0,0 +1,22 @@
+require 'active_record/associations/join_dependency/join_part'
+
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      class JoinBase < JoinPart # :nodoc:
+        def match?(other)
+          return true if self == other
+          super && base_klass == other.base_klass
+        end
+
+        def table
+          base_klass.arel_table
+        end
+
+        def aliased_table_name
+          base_klass.table_name
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_part.rb b/activerecord/lib/active_record/associations/join_dependency/join_part.rb
new file mode 100644
index 0000000000..91e1c6a9d7
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_part.rb
@@ -0,0 +1,72 @@
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      # A JoinPart represents a part of a JoinDependency. It is inherited
+      # by JoinBase and JoinAssociation. A JoinBase represents the Active Record which
+      # everything else is being joined onto. A JoinAssociation represents an association which
+      # is joining to the base. A JoinAssociation may result in more than one actual join
+      # operations (for example a has_and_belongs_to_many JoinAssociation would result in
+      # two; one for the join table and one for the target table).
+      class JoinPart # :nodoc:
+        include Enumerable
+
+        # The Active Record class which this join part is associated 'about'; for a JoinBase
+        # this is the actual base model, for a JoinAssociation this is the target model of the
+        # association.
+        attr_reader :base_klass, :children
+
+        delegate :table_name, :column_names, :primary_key, :to => :base_klass
+
+        def initialize(base_klass, children)
+          @base_klass = base_klass
+          @column_names_with_alias = nil
+          @children = children
+        end
+
+        def name
+          reflection.name
+        end
+
+        def match?(other)
+          self.class == other.class
+        end
+
+        def each(&block)
+          yield self
+          children.each { |child| child.each(&block) }
+        end
+
+        # An Arel::Table for the active_record
+        def table
+          raise NotImplementedError
+        end
+
+        # The alias for the active_record's table
+        def aliased_table_name
+          raise NotImplementedError
+        end
+
+        def extract_record(row, column_names_with_alias)
+          # This code is performance critical as it is called per row.
+          # see: https://github.com/rails/rails/pull/12185
+          hash = {}
+
+          index = 0
+          length = column_names_with_alias.length
+
+          while index < length
+            column_name, alias_name = column_names_with_alias[index]
+            hash[column_name] = row[alias_name]
+            index += 1
+          end
+
+          hash
+        end
+
+        def instantiate(row, aliases)
+          base_klass.instantiate(extract_record(row, aliases))
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader.rb b/activerecord/lib/active_record/associations/preloader.rb
new file mode 100644
index 0000000000..7519fec10a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader.rb
@@ -0,0 +1,193 @@
+module ActiveRecord
+  module Associations
+    # Implements the details of eager loading of Active Record associations.
+    #
+    # Note that 'eager loading' and 'preloading' are actually the same thing.
+    # However, there are two different eager loading strategies.
+    #
+    # The first one is by using table joins. This was only strategy available
+    # prior to Rails 2.1. Suppose that you have an Author model with columns
+    # 'name' and 'age', and a Book model with columns 'name' and 'sales'. Using
+    # this strategy, Active Record would try to retrieve all data for an author
+    # and all of its books via a single query:
+    #
+    #   SELECT * FROM authors
+    #   LEFT OUTER JOIN books ON authors.id = books.author_id
+    #   WHERE authors.name = 'Ken Akamatsu'
+    #
+    # However, this could result in many rows that contain redundant data. After
+    # having received the first row, we already have enough data to instantiate
+    # the Author object. In all subsequent rows, only the data for the joined
+    # 'books' table is useful; the joined 'authors' data is just redundant, and
+    # processing this redundant data takes memory and CPU time. The problem
+    # quickly becomes worse and worse as the level of eager loading increases
+    # (i.e. if Active Record is to eager load the associations' associations as
+    # well).
+    #
+    # The second strategy is to use multiple database queries, one for each
+    # level of association. Since Rails 2.1, this is the default strategy. In
+    # situations where a table join is necessary (e.g. when the +:conditions+
+    # option references an association's column), it will fallback to the table
+    # join strategy.
+    class Preloader #:nodoc:
+      extend ActiveSupport::Autoload
+
+      eager_autoload do
+        autoload :Association,           'active_record/associations/preloader/association'
+        autoload :SingularAssociation,   'active_record/associations/preloader/singular_association'
+        autoload :CollectionAssociation, 'active_record/associations/preloader/collection_association'
+        autoload :ThroughAssociation,    'active_record/associations/preloader/through_association'
+
+        autoload :HasMany,             'active_record/associations/preloader/has_many'
+        autoload :HasManyThrough,      'active_record/associations/preloader/has_many_through'
+        autoload :HasOne,              'active_record/associations/preloader/has_one'
+        autoload :HasOneThrough,       'active_record/associations/preloader/has_one_through'
+        autoload :BelongsTo,           'active_record/associations/preloader/belongs_to'
+      end
+
+      # Eager loads the named associations for the given Active Record record(s).
+      #
+      # In this description, 'association name' shall refer to the name passed
+      # to an association creation method. For example, a model that specifies
+      # <tt>belongs_to :author</tt>, <tt>has_many :buyers</tt> has association
+      # names +:author+ and +:buyers+.
+      #
+      # == Parameters
+      # +records+ is an array of ActiveRecord::Base. This array needs not be flat,
+      # i.e. +records+ itself may also contain arrays of records. In any case,
+      # +preload_associations+ will preload the all associations records by
+      # flattening +records+.
+      #
+      # +associations+ specifies one or more associations that you want to
+      # preload. It may be:
+      # - a Symbol or a String which specifies a single association name. For
+      #   example, specifying +:books+ allows this method to preload all books
+      #   for an Author.
+      # - an Array which specifies multiple association names. This array
+      #   is processed recursively. For example, specifying <tt>[:avatar, :books]</tt>
+      #   allows this method to preload an author's avatar as well as all of his
+      #   books.
+      # - a Hash which specifies multiple association names, as well as
+      #   association names for the to-be-preloaded association objects. For
+      #   example, specifying <tt>{ author: :avatar }</tt> will preload a
+      #   book's author, as well as that author's avatar.
+      #
+      # +:associations+ has the same format as the +:include+ option for
+      # <tt>ActiveRecord::Base.find</tt>. So +associations+ could look like this:
+      #
+      #   :books
+      #   [ :books, :author ]
+      #   { author: :avatar }
+      #   [ :books, { author: :avatar } ]
+
+      NULL_RELATION = Struct.new(:values, :bind_values).new({}, [])
+
+      def preload(records, associations, preload_scope = nil)
+        records       = Array.wrap(records).compact.uniq
+        associations  = Array.wrap(associations)
+        preload_scope = preload_scope || NULL_RELATION
+
+        if records.empty?
+          []
+        else
+          associations.flat_map { |association|
+            preloaders_on association, records, preload_scope
+          }
+        end
+      end
+
+      private
+
+      def preloaders_on(association, records, scope)
+        case association
+        when Hash
+          preloaders_for_hash(association, records, scope)
+        when Symbol
+          preloaders_for_one(association, records, scope)
+        when String
+          preloaders_for_one(association.to_sym, records, scope)
+        else
+          raise ArgumentError, "#{association.inspect} was not recognised for preload"
+        end
+      end
+
+      def preloaders_for_hash(association, records, scope)
+        association.flat_map { |parent, child|
+          loaders = preloaders_for_one parent, records, scope
+
+          recs = loaders.flat_map(&:preloaded_records).uniq
+          loaders.concat Array.wrap(child).flat_map { |assoc|
+            preloaders_on assoc, recs, scope
+          }
+          loaders
+        }
+      end
+
+      # Not all records have the same class, so group then preload group on the reflection
+      # itself so that if various subclass share the same association then we do not split
+      # them unnecessarily
+      #
+      # Additionally, polymorphic belongs_to associations can have multiple associated
+      # classes, depending on the polymorphic_type field. So we group by the classes as
+      # well.
+      def preloaders_for_one(association, records, scope)
+        grouped_records(association, records).flat_map do |reflection, klasses|
+          klasses.map do |rhs_klass, rs|
+            loader = preloader_for(reflection, rs, rhs_klass).new(rhs_klass, rs, reflection, scope)
+            loader.run self
+            loader
+          end
+        end
+      end
+
+      def grouped_records(association, records)
+        h = {}
+        records.each do |record|
+          next unless record
+          assoc = record.association(association)
+          klasses = h[assoc.reflection] ||= {}
+          (klasses[assoc.klass] ||= []) << record
+        end
+        h
+      end
+
+      class AlreadyLoaded
+        attr_reader :owners, :reflection
+
+        def initialize(klass, owners, reflection, preload_scope)
+          @owners = owners
+          @reflection = reflection
+        end
+
+        def run(preloader); end
+
+        def preloaded_records
+          owners.flat_map { |owner| owner.association(reflection.name).target }
+        end
+      end
+
+      class NullPreloader
+        def self.new(klass, owners, reflection, preload_scope); self; end
+        def self.run(preloader); end
+      end
+
+      def preloader_for(reflection, owners, rhs_klass)
+        return NullPreloader unless rhs_klass
+
+        if owners.first.association(reflection.name).loaded?
+          return AlreadyLoaded
+        end
+        reflection.check_preloadable!
+
+        case reflection.macro
+        when :has_many
+          reflection.options[:through] ? HasManyThrough : HasMany
+        when :has_one
+          reflection.options[:through] ? HasOneThrough : HasOne
+        when :belongs_to
+          BelongsTo
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/association.rb b/activerecord/lib/active_record/associations/preloader/association.rb
new file mode 100644
index 0000000000..c0639742be
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/association.rb
@@ -0,0 +1,167 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class Association #:nodoc:
+        attr_reader :owners, :reflection, :preload_scope, :model, :klass
+        attr_reader :preloaded_records
+
+        def initialize(klass, owners, reflection, preload_scope)
+          @klass         = klass
+          @owners        = owners
+          @reflection    = reflection
+          @preload_scope = preload_scope
+          @model         = owners.first && owners.first.class
+          @scope         = nil
+          @owners_by_key = nil
+          @preloaded_records = []
+        end
+
+        def run(preloader)
+          preload(preloader)
+        end
+
+        def preload(preloader)
+          raise NotImplementedError
+        end
+
+        def scope
+          @scope ||= build_scope
+        end
+
+        def records_for(ids)
+          query_scope(ids)
+        end
+
+        def query_scope(ids)
+          scope.where(association_key.in(ids))
+        end
+
+        def table
+          klass.arel_table
+        end
+
+        # The name of the key on the associated records
+        def association_key_name
+          raise NotImplementedError
+        end
+
+        # This is overridden by HABTM as the condition should be on the foreign_key column in
+        # the join table
+        def association_key
+          table[association_key_name]
+        end
+
+        # The name of the key on the model which declares the association
+        def owner_key_name
+          raise NotImplementedError
+        end
+
+        def owners_by_key
+          @owners_by_key ||= if key_conversion_required?
+                               owners.group_by do |owner|
+                                 owner[owner_key_name].to_s
+                               end
+                             else
+                               owners.group_by do |owner|
+                                 owner[owner_key_name]
+                               end
+                             end
+        end
+
+        def options
+          reflection.options
+        end
+
+        private
+
+        def associated_records_by_owner(preloader)
+          owners_map = owners_by_key
+          owner_keys = owners_map.keys.compact
+
+          # Each record may have multiple owners, and vice-versa
+          records_by_owner = owners.each_with_object({}) do |owner,h|
+            h[owner] = []
+          end
+
+          if owner_keys.any?
+            # Some databases impose a limit on the number of ids in a list (in Oracle it's 1000)
+            # Make several smaller queries if necessary or make one query if the adapter supports it
+            sliced  = owner_keys.each_slice(klass.connection.in_clause_length || owner_keys.size)
+
+            records = load_slices sliced
+            records.each do |record, owner_key|
+              owners_map[owner_key].each do |owner|
+                records_by_owner[owner] << record
+              end
+            end
+          end
+
+          records_by_owner
+        end
+
+        def key_conversion_required?
+          association_key_type != owner_key_type
+        end
+
+        def association_key_type
+          @klass.type_for_attribute(association_key_name.to_s).type
+        end
+
+        def owner_key_type
+          @model.type_for_attribute(owner_key_name.to_s).type
+        end
+
+        def load_slices(slices)
+          @preloaded_records = slices.flat_map { |slice|
+            records_for(slice)
+          }
+
+          @preloaded_records.map { |record|
+            key = record[association_key_name]
+            key = key.to_s if key_conversion_required?
+
+            [record, key]
+          }
+        end
+
+        def reflection_scope
+          @reflection_scope ||= reflection.scope ? klass.unscoped.instance_exec(nil, &reflection.scope) : klass.unscoped
+        end
+
+        def build_scope
+          scope = klass.unscoped
+
+          values         = reflection_scope.values
+          reflection_binds = reflection_scope.bind_values
+          preload_values = preload_scope.values
+          preload_binds  = preload_scope.bind_values
+
+          scope.where_values      = Array(values[:where])      + Array(preload_values[:where])
+          scope.references_values = Array(values[:references]) + Array(preload_values[:references])
+          scope.bind_values       = (reflection_binds + preload_binds)
+
+          scope._select!   preload_values[:select] || values[:select] || table[Arel.star]
+          scope.includes! preload_values[:includes] || values[:includes]
+
+          if preload_values.key? :order
+            scope.order! preload_values[:order]
+          else
+            if values.key? :order
+              scope.order! values[:order]
+            end
+          end
+
+          if preload_values[:readonly] || values[:readonly]
+            scope.readonly!
+          end
+
+          if options[:as]
+            scope.where!(klass.table_name => { reflection.type => model.base_class.sti_name })
+          end
+
+          klass.default_scoped.merge(scope)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/belongs_to.rb b/activerecord/lib/active_record/associations/preloader/belongs_to.rb
new file mode 100644
index 0000000000..5091d4717a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/belongs_to.rb
@@ -0,0 +1,17 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class BelongsTo < SingularAssociation #:nodoc:
+
+        def association_key_name
+          reflection.options[:primary_key] || klass && klass.primary_key
+        end
+
+        def owner_key_name
+          reflection.foreign_key
+        end
+
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/collection_association.rb b/activerecord/lib/active_record/associations/preloader/collection_association.rb
new file mode 100644
index 0000000000..5adffcd831
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/collection_association.rb
@@ -0,0 +1,24 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class CollectionAssociation < Association #:nodoc:
+
+        private
+
+        def build_scope
+          super.order(preload_scope.values[:order] || reflection_scope.values[:order])
+        end
+
+        def preload(preloader)
+          associated_records_by_owner(preloader).each do |owner, records|
+            association = owner.association(reflection.name)
+            association.loaded!
+            association.target.concat(records)
+            records.each { |record| association.set_inverse_instance(record) }
+          end
+        end
+
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/has_many.rb b/activerecord/lib/active_record/associations/preloader/has_many.rb
new file mode 100644
index 0000000000..3ea91a8c11
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_many.rb
@@ -0,0 +1,17 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasMany < CollectionAssociation #:nodoc:
+
+        def association_key_name
+          reflection.foreign_key
+        end
+
+        def owner_key_name
+          reflection.active_record_primary_key
+        end
+
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/has_many_through.rb b/activerecord/lib/active_record/associations/preloader/has_many_through.rb
new file mode 100644
index 0000000000..7b37b5942d
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_many_through.rb
@@ -0,0 +1,19 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasManyThrough < CollectionAssociation #:nodoc:
+        include ThroughAssociation
+
+        def associated_records_by_owner(preloader)
+          records_by_owner = super
+
+          if reflection_scope.distinct_value
+            records_by_owner.each_value { |records| records.uniq! }
+          end
+
+          records_by_owner
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/has_one.rb b/activerecord/lib/active_record/associations/preloader/has_one.rb
new file mode 100644
index 0000000000..24728e9f01
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_one.rb
@@ -0,0 +1,23 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasOne < SingularAssociation #:nodoc:
+
+        def association_key_name
+          reflection.foreign_key
+        end
+
+        def owner_key_name
+          reflection.active_record_primary_key
+        end
+
+        private
+
+        def build_scope
+          super.order(preload_scope.values[:order] || reflection_scope.values[:order])
+        end
+
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/has_one_through.rb b/activerecord/lib/active_record/associations/preloader/has_one_through.rb
new file mode 100644
index 0000000000..f063f85574
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_one_through.rb
@@ -0,0 +1,9 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasOneThrough < SingularAssociation #:nodoc:
+        include ThroughAssociation
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/singular_association.rb b/activerecord/lib/active_record/associations/preloader/singular_association.rb
new file mode 100644
index 0000000000..f60647a81e
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/singular_association.rb
@@ -0,0 +1,21 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class SingularAssociation < Association #:nodoc:
+
+        private
+
+        def preload(preloader)
+          associated_records_by_owner(preloader).each do |owner, associated_records|
+            record = associated_records.first
+
+            association = owner.association(reflection.name)
+            association.target = record
+            association.set_inverse_instance(record) if record
+          end
+        end
+
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/preloader/through_association.rb b/activerecord/lib/active_record/associations/preloader/through_association.rb
new file mode 100644
index 0000000000..1fed7f74e7
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/through_association.rb
@@ -0,0 +1,95 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      module ThroughAssociation #:nodoc:
+        def through_reflection
+          reflection.through_reflection
+        end
+
+        def source_reflection
+          reflection.source_reflection
+        end
+
+        def associated_records_by_owner(preloader)
+          preloader.preload(owners,
+                            through_reflection.name,
+                            through_scope)
+
+          through_records = owners.map do |owner|
+            association = owner.association through_reflection.name
+
+            [owner, Array(association.reader)]
+          end
+
+          reset_association owners, through_reflection.name
+
+          middle_records = through_records.flat_map { |(_,rec)| rec }
+
+          preloaders = preloader.preload(middle_records,
+                                         source_reflection.name,
+                                         reflection_scope)
+
+          @preloaded_records = preloaders.flat_map(&:preloaded_records)
+
+          middle_to_pl = preloaders.each_with_object({}) do |pl,h|
+            pl.owners.each { |middle|
+              h[middle] = pl
+            }
+          end
+
+          record_offset = {}
+          @preloaded_records.each_with_index do |record,i|
+            record_offset[record] = i
+          end
+
+          through_records.each_with_object({}) { |(lhs,center),records_by_owner|
+            pl_to_middle = center.group_by { |record| middle_to_pl[record] }
+
+            records_by_owner[lhs] = pl_to_middle.flat_map do |pl, middles|
+              rhs_records = middles.flat_map { |r|
+                association = r.association source_reflection.name
+
+                association.reader
+              }.compact
+
+              rhs_records.sort_by { |rhs| record_offset[rhs] }
+            end
+          }
+        end
+
+        private
+
+        def reset_association(owners, association_name)
+          should_reset = (through_scope != through_reflection.klass.unscoped) ||
+             (reflection.options[:source_type] && through_reflection.collection?)
+
+          # Dont cache the association - we would only be caching a subset
+          if should_reset
+            owners.each { |owner|
+              owner.association(association_name).reset
+            }
+          end
+        end
+
+
+        def through_scope
+          scope = through_reflection.klass.unscoped
+
+          if options[:source_type]
+            scope.where! reflection.foreign_type => options[:source_type]
+          else
+            unless reflection_scope.where_values.empty?
+              scope.includes_values = Array(reflection_scope.values[:includes] || options[:source])
+              scope.where_values    = reflection_scope.values[:where]
+            end
+
+            scope.references! reflection_scope.values[:references]
+            scope = scope.order reflection_scope.values[:order] if scope.eager_loading?
+          end
+
+          scope
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/singular_association.rb b/activerecord/lib/active_record/associations/singular_association.rb
new file mode 100644
index 0000000000..f2e3a4e40f
--- /dev/null
+++ b/activerecord/lib/active_record/associations/singular_association.rb
@@ -0,0 +1,80 @@
+module ActiveRecord
+  module Associations
+    class SingularAssociation < Association #:nodoc:
+      # Implements the reader method, e.g. foo.bar for Foo.has_one :bar
+      def reader(force_reload = false)
+        if force_reload
+          klass.uncached { reload }
+        elsif !loaded? || stale_target?
+          reload
+        end
+
+        target
+      end
+
+      # Implements the writer method, e.g. foo.bar= for Foo.belongs_to :bar
+      def writer(record)
+        replace(record)
+      end
+
+      def create(attributes = {}, &block)
+        _create_record(attributes, &block)
+      end
+
+      def create!(attributes = {}, &block)
+        _create_record(attributes, true, &block)
+      end
+
+      def build(attributes = {})
+        record = build_record(attributes)
+        yield(record) if block_given?
+        set_new_record(record)
+        record
+      end
+
+      private
+
+        def create_scope
+          scope.scope_for_create.stringify_keys.except(klass.primary_key)
+        end
+
+        def get_records
+          return scope.limit(1).to_a if reflection.scope_chain.any?(&:any?)
+
+          conn = klass.connection
+          sc = reflection.association_scope_cache(conn, owner) do
+            StatementCache.create(conn) { |params|
+              as = AssociationScope.create { params.bind }
+              target_scope.merge(as.scope(self, conn)).limit(1)
+            }
+          end
+
+          binds = AssociationScope.get_bind_values(owner, reflection.chain)
+          sc.execute binds, klass, klass.connection
+        end
+
+        def find_target
+          if record = get_records.first
+            set_inverse_instance record
+          end
+        end
+
+        def replace(record)
+          raise NotImplementedError, "Subclasses must implement a replace(record) method"
+        end
+
+        def set_new_record(record)
+          replace(record)
+        end
+
+        def _create_record(attributes, raise_error = false)
+          record = build_record(attributes)
+          yield(record) if block_given?
+          saved = record.save
+          set_new_record(record)
+          raise RecordInvalid.new(record) if !saved && raise_error
+          record
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb
new file mode 100644
index 0000000000..611d471e62
--- /dev/null
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -0,0 +1,92 @@
+module ActiveRecord
+  # = Active Record Through Association
+  module Associations
+    module ThroughAssociation #:nodoc:
+
+      delegate :source_reflection, :through_reflection, :to => :reflection
+
+      protected
+
+        # We merge in these scopes for two reasons:
+        #
+        #   1. To get the default_scope conditions for any of the other reflections in the chain
+        #   2. To get the type conditions for any STI models in the chain
+        def target_scope
+          scope = super
+          reflection.chain.drop(1).each do |reflection|
+            relation = reflection.klass.all
+            relation.merge!(reflection.scope) if reflection.scope
+
+            scope.merge!(
+              relation.except(:select, :create_with, :includes, :preload, :joins, :eager_load)
+            )
+          end
+          scope
+        end
+
+      private
+
+        # Construct attributes for :through pointing to owner and associate. This is used by the
+        # methods which create and delete records on the association.
+        #
+        # We only support indirectly modifying through associations which has a belongs_to source.
+        # This is the "has_many :tags, through: :taggings" situation, where the join model
+        # typically has a belongs_to on both side. In other words, associations which could also
+        # be represented as has_and_belongs_to_many associations.
+        #
+        # We do not support creating/deleting records on the association where the source has
+        # some other type, because this opens up a whole can of worms, and in basically any
+        # situation it is more natural for the user to just create or modify their join records
+        # directly as required.
+        def construct_join_attributes(*records)
+          ensure_mutable
+
+          if source_reflection.association_primary_key(reflection.klass) == reflection.klass.primary_key
+            join_attributes = { source_reflection.name => records }
+          else
+            join_attributes = {
+              source_reflection.foreign_key =>
+                records.map { |record|
+                  record.send(source_reflection.association_primary_key(reflection.klass))
+                }
+            }
+          end
+
+          if options[:source_type]
+            join_attributes[source_reflection.foreign_type] =
+              records.map { |record| record.class.base_class.name }
+          end
+
+          if records.count == 1
+            Hash[join_attributes.map { |k, v| [k, v.first] }]
+          else
+            join_attributes
+          end
+        end
+
+        # Note: this does not capture all cases, for example it would be crazy to try to
+        # properly support stale-checking for nested associations.
+        def stale_state
+          if through_reflection.belongs_to?
+            owner[through_reflection.foreign_key] && owner[through_reflection.foreign_key].to_s
+          end
+        end
+
+        def foreign_key_present?
+          through_reflection.belongs_to? && !owner[through_reflection.foreign_key].nil?
+        end
+
+        def ensure_mutable
+          unless source_reflection.belongs_to?
+            raise HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(owner, reflection)
+          end
+        end
+
+        def ensure_not_nested
+          if reflection.nested?
+            raise HasManyThroughNestedAssociationsAreReadonly.new(owner, reflection)
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute.rb b/activerecord/lib/active_record/attribute.rb
new file mode 100644
index 0000000000..6d38224830
--- /dev/null
+++ b/activerecord/lib/active_record/attribute.rb
@@ -0,0 +1,120 @@
+module ActiveRecord
+  class Attribute # :nodoc:
+    class << self
+      def from_database(name, value, type)
+        FromDatabase.new(name, value, type)
+      end
+
+      def from_user(name, value, type)
+        FromUser.new(name, value, type)
+      end
+
+      def null(name)
+        Null.new(name)
+      end
+
+      def uninitialized(name, type)
+        Uninitialized.new(name, type)
+      end
+    end
+
+    attr_reader :name, :value_before_type_cast, :type
+
+    # This method should not be called directly.
+    # Use #from_database or #from_user
+    def initialize(name, value_before_type_cast, type)
+      @name = name
+      @value_before_type_cast = value_before_type_cast
+      @type = type
+    end
+
+    def value
+      # `defined?` is cheaper than `||=` when we get back falsy values
+      @value = type_cast(value_before_type_cast) unless defined?(@value)
+      @value
+    end
+
+    def value_for_database
+      type.type_cast_for_database(value)
+    end
+
+    def changed_from?(old_value)
+      type.changed?(old_value, value, value_before_type_cast)
+    end
+
+    def changed_in_place_from?(old_value)
+      type.changed_in_place?(old_value, value)
+    end
+
+    def with_value_from_user(value)
+      self.class.from_user(name, value, type)
+    end
+
+    def with_value_from_database(value)
+      self.class.from_database(name, value, type)
+    end
+
+    def type_cast
+      raise NotImplementedError
+    end
+
+    def initialized?
+      true
+    end
+
+    protected
+
+    def initialize_dup(other)
+      if defined?(@value) && @value.duplicable?
+        @value = @value.dup
+      end
+    end
+
+    class FromDatabase < Attribute # :nodoc:
+      def type_cast(value)
+        type.type_cast_from_database(value)
+      end
+    end
+
+    class FromUser < Attribute # :nodoc:
+      def type_cast(value)
+        type.type_cast_from_user(value)
+      end
+    end
+
+    class Null < Attribute # :nodoc:
+      def initialize(name)
+        super(name, nil, Type::Value.new)
+      end
+
+      def value
+        nil
+      end
+
+      def with_value_from_database(value)
+        raise ActiveModel::MissingAttributeError, "can't write unknown attribute `#{name}`"
+      end
+      alias_method :with_value_from_user, :with_value_from_database
+    end
+
+    class Uninitialized < Attribute # :nodoc:
+      def initialize(name, type)
+        super(name, nil, type)
+      end
+
+      def value
+        if block_given?
+          yield name
+        end
+      end
+
+      def value_for_database
+      end
+
+      def initialized?
+        false
+      end
+    end
+    private_constant :FromDatabase, :FromUser, :Null, :Uninitialized
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_assignment.rb b/activerecord/lib/active_record/attribute_assignment.rb
new file mode 100644
index 0000000000..2887db3bf7
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_assignment.rb
@@ -0,0 +1,212 @@
+require 'active_model/forbidden_attributes_protection'
+
+module ActiveRecord
+  module AttributeAssignment
+    extend ActiveSupport::Concern
+    include ActiveModel::ForbiddenAttributesProtection
+
+    # Allows you to set all the attributes by passing in a hash of attributes with
+    # keys matching the attribute names (which again matches the column names).
+    #
+    # If the passed hash responds to <tt>permitted?</tt> method and the return value
+    # of this method is +false+ an <tt>ActiveModel::ForbiddenAttributesError</tt>
+    # exception is raised.
+    #
+    #   cat = Cat.new(name: "Gorby", status: "yawning")
+    #   cat.attributes # =>  { "name" => "Gorby", "status" => "yawning", "created_at" => nil, "updated_at" => nil}
+    #   cat.assign_attributes(status: "sleeping")
+    #   cat.attributes # =>  { "name" => "Gorby", "status" => "sleeping", "created_at" => nil, "updated_at" => nil }
+    #
+    # New attributes will be persisted in the database when the object is saved.
+    #
+    # Aliased to <tt>attributes=</tt>.
+    def assign_attributes(new_attributes)
+      if !new_attributes.respond_to?(:stringify_keys)
+        raise ArgumentError, "When assigning attributes, you must pass a hash as an argument."
+      end
+      return if new_attributes.blank?
+
+      attributes                  = new_attributes.stringify_keys
+      multi_parameter_attributes  = []
+      nested_parameter_attributes = []
+
+      attributes = sanitize_for_mass_assignment(attributes)
+
+      attributes.each do |k, v|
+        if k.include?("(")
+          multi_parameter_attributes << [ k, v ]
+        elsif v.is_a?(Hash)
+          nested_parameter_attributes << [ k, v ]
+        else
+          _assign_attribute(k, v)
+        end
+      end
+
+      assign_nested_parameter_attributes(nested_parameter_attributes) unless nested_parameter_attributes.empty?
+      assign_multiparameter_attributes(multi_parameter_attributes) unless multi_parameter_attributes.empty?
+    end
+
+    alias attributes= assign_attributes
+
+    private
+
+    def _assign_attribute(k, v)
+      public_send("#{k}=", v)
+    rescue NoMethodError
+      if respond_to?("#{k}=")
+        raise
+      else
+        raise UnknownAttributeError.new(self, k)
+      end
+    end
+
+    # Assign any deferred nested attributes after the base attributes have been set.
+    def assign_nested_parameter_attributes(pairs)
+      pairs.each { |k, v| _assign_attribute(k, v) }
+    end
+
+    # Instantiates objects for all attribute classes that needs more than one constructor parameter. This is done
+    # by calling new on the column type or aggregation type (through composed_of) object with these parameters.
+    # So having the pairs written_on(1) = "2004", written_on(2) = "6", written_on(3) = "24", will instantiate
+    # written_on (a date type) with Date.new("2004", "6", "24"). You can also specify a typecast character in the
+    # parentheses to have the parameters typecasted before they're used in the constructor. Use i for Fixnum and
+    # f for Float. If all the values for a given attribute are empty, the attribute will be set to +nil+.
+    def assign_multiparameter_attributes(pairs)
+      execute_callstack_for_multiparameter_attributes(
+        extract_callstack_for_multiparameter_attributes(pairs)
+      )
+    end
+
+    def execute_callstack_for_multiparameter_attributes(callstack)
+      errors = []
+      callstack.each do |name, values_with_empty_parameters|
+        begin
+          send("#{name}=", MultiparameterAttribute.new(self, name, values_with_empty_parameters).read_value)
+        rescue => ex
+          errors << AttributeAssignmentError.new("error on assignment #{values_with_empty_parameters.values.inspect} to #{name} (#{ex.message})", ex, name)
+        end
+      end
+      unless errors.empty?
+        error_descriptions = errors.map { |ex| ex.message }.join(",")
+        raise MultiparameterAssignmentErrors.new(errors), "#{errors.size} error(s) on assignment of multiparameter attributes [#{error_descriptions}]"
+      end
+    end
+
+    def extract_callstack_for_multiparameter_attributes(pairs)
+      attributes = {}
+
+      pairs.each do |(multiparameter_name, value)|
+        attribute_name = multiparameter_name.split("(").first
+        attributes[attribute_name] ||= {}
+
+        parameter_value = value.empty? ? nil : type_cast_attribute_value(multiparameter_name, value)
+        attributes[attribute_name][find_parameter_position(multiparameter_name)] ||= parameter_value
+      end
+
+      attributes
+    end
+
+    def type_cast_attribute_value(multiparameter_name, value)
+      multiparameter_name =~ /\([0-9]*([if])\)/ ? value.send("to_" + $1) : value
+    end
+
+    def find_parameter_position(multiparameter_name)
+      multiparameter_name.scan(/\(([0-9]*).*\)/).first.first.to_i
+    end
+
+    class MultiparameterAttribute #:nodoc:
+      attr_reader :object, :name, :values, :cast_type
+
+      def initialize(object, name, values)
+        @object = object
+        @name   = name
+        @values = values
+      end
+
+      def read_value
+        return if values.values.compact.empty?
+
+        @cast_type = object.type_for_attribute(name)
+        klass = cast_type.klass
+
+        if klass == Time
+          read_time
+        elsif klass == Date
+          read_date
+        else
+          read_other
+        end
+      end
+
+      private
+
+      def instantiate_time_object(set_values)
+        if object.class.send(:create_time_zone_conversion_attribute?, name, cast_type)
+          Time.zone.local(*set_values)
+        else
+          Time.send(object.class.default_timezone, *set_values)
+        end
+      end
+
+      def read_time
+        # If column is a :time (and not :date or :datetime) there is no need to validate if
+        # there are year/month/day fields
+        if cast_type.type == :time
+          # if the column is a time set the values to their defaults as January 1, 1970, but only if they're nil
+          { 1 => 1970, 2 => 1, 3 => 1 }.each do |key,value|
+            values[key] ||= value
+          end
+        else
+          # else column is a timestamp, so if Date bits were not provided, error
+          validate_required_parameters!([1,2,3])
+
+          # If Date bits were provided but blank, then return nil
+          return if blank_date_parameter?
+        end
+
+        max_position = extract_max_param(6)
+        set_values   = values.values_at(*(1..max_position))
+        # If Time bits are not there, then default to 0
+        (3..5).each { |i| set_values[i] = set_values[i].presence || 0 }
+        instantiate_time_object(set_values)
+      end
+
+      def read_date
+        return if blank_date_parameter?
+        set_values = values.values_at(1,2,3)
+        begin
+          Date.new(*set_values)
+        rescue ArgumentError # if Date.new raises an exception on an invalid date
+          instantiate_time_object(set_values).to_date # we instantiate Time object and convert it back to a date thus using Time's logic in handling invalid dates
+        end
+      end
+
+      def read_other
+        max_position = extract_max_param
+        positions    = (1..max_position)
+        validate_required_parameters!(positions)
+
+        values.slice(*positions)
+      end
+
+      # Checks whether some blank date parameter exists. Note that this is different
+      # than the validate_required_parameters! method, since it just checks for blank
+      # positions instead of missing ones, and does not raise in case one blank position
+      # exists. The caller is responsible to handle the case of this returning true.
+      def blank_date_parameter?
+        (1..3).any? { |position| values[position].blank? }
+      end
+
+      # If some position is not provided, it errors out a missing parameter exception.
+      def validate_required_parameters!(positions)
+        if missing_parameter = positions.detect { |position| !values.key?(position) }
+          raise ArgumentError.new("Missing Parameter - #{name}(#{missing_parameter})")
+        end
+      end
+
+      def extract_max_param(upper_cap = 100)
+        [values.keys.max, upper_cap].min
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_decorators.rb b/activerecord/lib/active_record/attribute_decorators.rb
new file mode 100644
index 0000000000..5b96623b6e
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_decorators.rb
@@ -0,0 +1,66 @@
+module ActiveRecord
+  module AttributeDecorators # :nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :attribute_type_decorations, instance_accessor: false # :internal:
+      self.attribute_type_decorations = TypeDecorator.new
+    end
+
+    module ClassMethods # :nodoc:
+      def decorate_attribute_type(column_name, decorator_name, &block)
+        matcher = ->(name, _) { name == column_name.to_s }
+        key = "_#{column_name}_#{decorator_name}"
+        decorate_matching_attribute_types(matcher, key, &block)
+      end
+
+      def decorate_matching_attribute_types(matcher, decorator_name, &block)
+        clear_caches_calculated_from_columns
+        decorator_name = decorator_name.to_s
+
+        # Create new hashes so we don't modify parent classes
+        self.attribute_type_decorations = attribute_type_decorations.merge(decorator_name => [matcher, block])
+      end
+
+      private
+
+      def add_user_provided_columns(*)
+        super.map do |column|
+          decorated_type = attribute_type_decorations.apply(column.name, column.cast_type)
+          column.with_type(decorated_type)
+        end
+      end
+    end
+
+    class TypeDecorator # :nodoc:
+      delegate :clear, to: :@decorations
+
+      def initialize(decorations = {})
+        @decorations = decorations
+      end
+
+      def merge(*args)
+        TypeDecorator.new(@decorations.merge(*args))
+      end
+
+      def apply(name, type)
+        decorations = decorators_for(name, type)
+        decorations.inject(type) do |new_type, block|
+          block.call(new_type)
+        end
+      end
+
+      private
+
+      def decorators_for(name, type)
+        matching(name, type).map(&:last)
+      end
+
+      def matching(name, type)
+        @decorations.values.select do |(matcher, _)|
+          matcher.call(name, type)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
new file mode 100644
index 0000000000..a2bb78dfcc
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -0,0 +1,433 @@
+require 'active_support/core_ext/enumerable'
+require 'mutex_m'
+require 'thread_safe'
+
+module ActiveRecord
+  # = Active Record Attribute Methods
+  module AttributeMethods
+    extend ActiveSupport::Concern
+    include ActiveModel::AttributeMethods
+
+    included do
+      initialize_generated_modules
+      include Read
+      include Write
+      include BeforeTypeCast
+      include Query
+      include PrimaryKey
+      include TimeZoneConversion
+      include Dirty
+      include Serialization
+
+      delegate :column_for_attribute, to: :class
+    end
+
+    AttrNames = Module.new {
+      def self.set_name_cache(name, value)
+        const_name = "ATTR_#{name}"
+        unless const_defined? const_name
+          const_set const_name, value.dup.freeze
+        end
+      end
+    }
+
+    BLACKLISTED_CLASS_METHODS = %w(private public protected)
+
+    class AttributeMethodCache
+      def initialize
+        @module = Module.new
+        @method_cache = ThreadSafe::Cache.new
+      end
+
+      def [](name)
+        @method_cache.compute_if_absent(name) do
+          safe_name = name.unpack('h*').first
+          temp_method = "__temp__#{safe_name}"
+          ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+          @module.module_eval method_body(temp_method, safe_name), __FILE__, __LINE__
+          @module.instance_method temp_method
+        end
+      end
+
+      private
+
+      # Override this method in the subclasses for method body.
+      def method_body(method_name, const_name)
+        raise NotImplementedError, "Subclasses must implement a method_body(method_name, const_name) method."
+      end
+    end
+
+    module ClassMethods
+      def inherited(child_class) #:nodoc:
+        child_class.initialize_generated_modules
+        super
+      end
+
+      def initialize_generated_modules # :nodoc:
+        @generated_attribute_methods = Module.new { extend Mutex_m }
+        @attribute_methods_generated = false
+        include @generated_attribute_methods
+      end
+
+      # Generates all the attribute related methods for columns in the database
+      # accessors, mutators and query methods.
+      def define_attribute_methods # :nodoc:
+        return false if @attribute_methods_generated
+        # Use a mutex; we don't want two threads simultaneously trying to define
+        # attribute methods.
+        generated_attribute_methods.synchronize do
+          return false if @attribute_methods_generated
+          superclass.define_attribute_methods unless self == base_class
+          super(column_names)
+          @attribute_methods_generated = true
+        end
+        true
+      end
+
+      def undefine_attribute_methods # :nodoc:
+        generated_attribute_methods.synchronize do
+          super if @attribute_methods_generated
+          @attribute_methods_generated = false
+        end
+      end
+
+      # Raises a <tt>ActiveRecord::DangerousAttributeError</tt> exception when an
+      # \Active \Record method is defined in the model, otherwise +false+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     def save
+      #       'already defined by Active Record'
+      #     end
+      #   end
+      #
+      #   Person.instance_method_already_implemented?(:save)
+      #   # => ActiveRecord::DangerousAttributeError: save is defined by ActiveRecord
+      #
+      #   Person.instance_method_already_implemented?(:name)
+      #   # => false
+      def instance_method_already_implemented?(method_name)
+        if dangerous_attribute_method?(method_name)
+          raise DangerousAttributeError, "#{method_name} is defined by Active Record"
+        end
+
+        if superclass == Base
+          super
+        else
+          # If B < A and A defines its own attribute method, then we don't want to overwrite that.
+          defined = method_defined_within?(method_name, superclass, superclass.generated_attribute_methods)
+          base_defined = Base.method_defined?(method_name) || Base.private_method_defined?(method_name)
+          defined && !base_defined || super
+        end
+      end
+
+      # A method name is 'dangerous' if it is already (re)defined by Active Record, but
+      # not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
+      def dangerous_attribute_method?(name) # :nodoc:
+        method_defined_within?(name, Base)
+      end
+
+      def method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc:
+        if klass.method_defined?(name) || klass.private_method_defined?(name)
+          if superklass.method_defined?(name) || superklass.private_method_defined?(name)
+            klass.instance_method(name).owner != superklass.instance_method(name).owner
+          else
+            true
+          end
+        else
+          false
+        end
+      end
+
+      # A class method is 'dangerous' if it is already (re)defined by Active Record, but
+      # not by any ancestors. (So 'puts' is not dangerous but 'new' is.)
+      def dangerous_class_method?(method_name)
+        BLACKLISTED_CLASS_METHODS.include?(method_name.to_s) || class_method_defined_within?(method_name, Base)
+      end
+
+      def class_method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc
+        if klass.respond_to?(name, true)
+          if superklass.respond_to?(name, true)
+            klass.method(name).owner != superklass.method(name).owner
+          else
+            true
+          end
+        else
+          false
+        end
+      end
+
+      # Returns +true+ if +attribute+ is an attribute method and table exists,
+      # +false+ otherwise.
+      #
+      #   class Person < ActiveRecord::Base
+      #   end
+      #
+      #   Person.attribute_method?('name')   # => true
+      #   Person.attribute_method?(:age=)    # => true
+      #   Person.attribute_method?(:nothing) # => false
+      def attribute_method?(attribute)
+        super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, '')))
+      end
+
+      # Returns an array of column names as strings if it's not an abstract class and
+      # table exists. Otherwise it returns an empty array.
+      #
+      #   class Person < ActiveRecord::Base
+      #   end
+      #
+      #   Person.attribute_names
+      #   # => ["id", "created_at", "updated_at", "name", "age"]
+      def attribute_names
+        @attribute_names ||= if !abstract_class? && table_exists?
+            column_names
+          else
+            []
+          end
+      end
+
+      # Returns the column object for the named attribute.
+      # Returns nil if the named attribute does not exist.
+      #
+      #   class Person < ActiveRecord::Base
+      #   end
+      #
+      #   person = Person.new
+      #   person.column_for_attribute(:name) # the result depends on the ConnectionAdapter
+      #   # => #<ActiveRecord::ConnectionAdapters::Column:0x007ff4ab083980 @name="name", @sql_type="varchar(255)", @null=true, ...>
+      #
+      #   person.column_for_attribute(:nothing)
+      #   # => nil
+      def column_for_attribute(name)
+        column = columns_hash[name.to_s]
+        if column.nil?
+          ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
+            `column_for_attribute` will return a null object for non-existent columns
+            in Rails 5.0. Use `has_attribute?` if you need to check for an
+            attribute's existence.
+          MESSAGE
+        end
+        column
+      end
+    end
+
+    # A Person object with a name attribute can ask <tt>person.respond_to?(:name)</tt>,
+    # <tt>person.respond_to?(:name=)</tt>, and <tt>person.respond_to?(:name?)</tt>
+    # which will all return +true+. It also define the attribute methods if they have
+    # not been generated.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.new
+    #   person.respond_to(:name)    # => true
+    #   person.respond_to(:name=)   # => true
+    #   person.respond_to(:name?)   # => true
+    #   person.respond_to('age')    # => true
+    #   person.respond_to('age=')   # => true
+    #   person.respond_to('age?')   # => true
+    #   person.respond_to(:nothing) # => false
+    def respond_to?(name, include_private = false)
+      return false unless super
+      name = name.to_s
+
+      # If the result is true then check for the select case.
+      # For queries selecting a subset of columns, return false for unselected columns.
+      # We check defined?(@attributes) not to issue warnings if called on objects that
+      # have been allocated but not yet initialized.
+      if defined?(@attributes) && self.class.column_names.include?(name)
+        return has_attribute?(name)
+      end
+
+      return true
+    end
+
+    # Returns +true+ if the given attribute is in the attributes hash, otherwise +false+.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.new
+    #   person.has_attribute?(:name)    # => true
+    #   person.has_attribute?('age')    # => true
+    #   person.has_attribute?(:nothing) # => false
+    def has_attribute?(attr_name)
+      @attributes.key?(attr_name.to_s)
+    end
+
+    # Returns an array of names for the attributes available on this object.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.new
+    #   person.attribute_names
+    #   # => ["id", "created_at", "updated_at", "name", "age"]
+    def attribute_names
+      @attributes.keys
+    end
+
+    # Returns a hash of all the attributes with their names as keys and the values of the attributes as values.
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.create(name: 'Francesco', age: 22)
+    #   person.attributes
+    #   # => {"id"=>3, "created_at"=>Sun, 21 Oct 2012 04:53:04, "updated_at"=>Sun, 21 Oct 2012 04:53:04, "name"=>"Francesco", "age"=>22}
+    def attributes
+      @attributes.to_hash
+    end
+
+    # Returns an <tt>#inspect</tt>-like string for the value of the
+    # attribute +attr_name+. String attributes are truncated upto 50
+    # characters, Date and Time attributes are returned in the
+    # <tt>:db</tt> format, Array attributes are truncated upto 10 values.
+    # Other attributes return the value of <tt>#inspect</tt> without
+    # modification.
+    #
+    #   person = Person.create!(name: 'David Heinemeier Hansson ' * 3)
+    #
+    #   person.attribute_for_inspect(:name)
+    #   # => "\"David Heinemeier Hansson David Heinemeier Hansson ...\""
+    #
+    #   person.attribute_for_inspect(:created_at)
+    #   # => "\"2012-10-22 00:15:07\""
+    #
+    #   person.attribute_for_inspect(:tag_ids)
+    #   # => "[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ...]"
+    def attribute_for_inspect(attr_name)
+      value = read_attribute(attr_name)
+
+      if value.is_a?(String) && value.length > 50
+        "#{value[0, 50]}...".inspect
+      elsif value.is_a?(Date) || value.is_a?(Time)
+        %("#{value.to_s(:db)}")
+      elsif value.is_a?(Array) && value.size > 10
+        inspected = value.first(10).inspect
+        %(#{inspected[0...-1]}, ...])
+      else
+        value.inspect
+      end
+    end
+
+    # Returns +true+ if the specified +attribute+ has been set by the user or by a
+    # database load and is neither +nil+ nor <tt>empty?</tt> (the latter only applies
+    # to objects that respond to <tt>empty?</tt>, most notably Strings). Otherwise, +false+.
+    # Note that it always returns +true+ with boolean attributes.
+    #
+    #   class Task < ActiveRecord::Base
+    #   end
+    #
+    #   task = Task.new(title: '', is_done: false)
+    #   task.attribute_present?(:title)   # => false
+    #   task.attribute_present?(:is_done) # => true
+    #   task.title = 'Buy milk'
+    #   task.is_done = true
+    #   task.attribute_present?(:title)   # => true
+    #   task.attribute_present?(:is_done) # => true
+    def attribute_present?(attribute)
+      value = read_attribute(attribute)
+      !value.nil? && !(value.respond_to?(:empty?) && value.empty?)
+    end
+
+    # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
+    # "2004-12-12" in a date column is cast to a date object, like Date.new(2004, 12, 12)). It raises
+    # <tt>ActiveModel::MissingAttributeError</tt> if the identified attribute is missing.
+    #
+    # Note: +:id+ is always present.
+    #
+    # Alias for the <tt>read_attribute</tt> method.
+    #
+    #   class Person < ActiveRecord::Base
+    #     belongs_to :organization
+    #   end
+    #
+    #   person = Person.new(name: 'Francesco', age: '22')
+    #   person[:name] # => "Francesco"
+    #   person[:age]  # => 22
+    #
+    #   person = Person.select('id').first
+    #   person[:name]            # => ActiveModel::MissingAttributeError: missing attribute: name
+    #   person[:organization_id] # => ActiveModel::MissingAttributeError: missing attribute: organization_id
+    def [](attr_name)
+      read_attribute(attr_name) { |n| missing_attribute(n, caller) }
+    end
+
+    # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+.
+    # (Alias for the protected <tt>write_attribute</tt> method).
+    #
+    #   class Person < ActiveRecord::Base
+    #   end
+    #
+    #   person = Person.new
+    #   person[:age] = '22'
+    #   person[:age] # => 22
+    #   person[:age] # => Fixnum
+    def []=(attr_name, value)
+      write_attribute(attr_name, value)
+    end
+
+    protected
+
+    def clone_attribute_value(reader_method, attribute_name) # :nodoc:
+      value = send(reader_method, attribute_name)
+      value.duplicable? ? value.clone : value
+    rescue TypeError, NoMethodError
+      value
+    end
+
+    def arel_attributes_with_values_for_create(attribute_names) # :nodoc:
+      arel_attributes_with_values(attributes_for_create(attribute_names))
+    end
+
+    def arel_attributes_with_values_for_update(attribute_names) # :nodoc:
+      arel_attributes_with_values(attributes_for_update(attribute_names))
+    end
+
+    def attribute_method?(attr_name) # :nodoc:
+      # We check defined? because Syck calls respond_to? before actually calling initialize.
+      defined?(@attributes) && @attributes.key?(attr_name)
+    end
+
+    private
+
+    # Returns a Hash of the Arel::Attributes and attribute values that have been
+    # typecasted for use in an Arel insert/update method.
+    def arel_attributes_with_values(attribute_names)
+      attrs = {}
+      arel_table = self.class.arel_table
+
+      attribute_names.each do |name|
+        attrs[arel_table[name]] = typecasted_attribute_value(name)
+      end
+      attrs
+    end
+
+    # Filters the primary keys and readonly attributes from the attribute names.
+    def attributes_for_update(attribute_names)
+      attribute_names.reject do |name|
+        readonly_attribute?(name)
+      end
+    end
+
+    # Filters out the primary keys, from the attribute names, when the primary
+    # key is to be generated (e.g. the id attribute has no value).
+    def attributes_for_create(attribute_names)
+      attribute_names.reject do |name|
+        pk_attribute?(name) && id.nil?
+      end
+    end
+
+    def readonly_attribute?(name)
+      self.class.readonly_attributes.include?(name)
+    end
+
+    def pk_attribute?(name)
+      name == self.class.primary_key
+    end
+
+    def typecasted_attribute_value(name)
+      read_attribute(name)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/before_type_cast.rb b/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
new file mode 100644
index 0000000000..fd61febd57
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
@@ -0,0 +1,71 @@
+module ActiveRecord
+  module AttributeMethods
+    # = Active Record Attribute Methods Before Type Cast
+    #
+    # <tt>ActiveRecord::AttributeMethods::BeforeTypeCast</tt> provides a way to
+    # read the value of the attributes before typecasting and deserialization.
+    #
+    #   class Task < ActiveRecord::Base
+    #   end
+    #
+    #   task = Task.new(id: '1', completed_on: '2012-10-21')
+    #   task.id           # => 1
+    #   task.completed_on # => Sun, 21 Oct 2012
+    #
+    #   task.attributes_before_type_cast
+    #   # => {"id"=>"1", "completed_on"=>"2012-10-21", ... }
+    #   task.read_attribute_before_type_cast('id')           # => "1"
+    #   task.read_attribute_before_type_cast('completed_on') # => "2012-10-21"
+    #
+    # In addition to #read_attribute_before_type_cast and #attributes_before_type_cast,
+    # it declares a method for all attributes with the <tt>*_before_type_cast</tt>
+    # suffix.
+    #
+    #   task.id_before_type_cast           # => "1"
+    #   task.completed_on_before_type_cast # => "2012-10-21"
+    module BeforeTypeCast
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "_before_type_cast"
+      end
+
+      # Returns the value of the attribute identified by +attr_name+ before
+      # typecasting and deserialization.
+      #
+      #   class Task < ActiveRecord::Base
+      #   end
+      #
+      #   task = Task.new(id: '1', completed_on: '2012-10-21')
+      #   task.read_attribute('id')                            # => 1
+      #   task.read_attribute_before_type_cast('id')           # => '1'
+      #   task.read_attribute('completed_on')                  # => Sun, 21 Oct 2012
+      #   task.read_attribute_before_type_cast('completed_on') # => "2012-10-21"
+      #   task.read_attribute_before_type_cast(:completed_on)  # => "2012-10-21"
+      def read_attribute_before_type_cast(attr_name)
+        @attributes[attr_name.to_s].value_before_type_cast
+      end
+
+      # Returns a hash of attributes before typecasting and deserialization.
+      #
+      #   class Task < ActiveRecord::Base
+      #   end
+      #
+      #   task = Task.new(title: nil, is_done: true, completed_on: '2012-10-21')
+      #   task.attributes
+      #   # => {"id"=>nil, "title"=>nil, "is_done"=>true, "completed_on"=>Sun, 21 Oct 2012, "created_at"=>nil, "updated_at"=>nil}
+      #   task.attributes_before_type_cast
+      #   # => {"id"=>nil, "title"=>nil, "is_done"=>true, "completed_on"=>"2012-10-21", "created_at"=>nil, "updated_at"=>nil}
+      def attributes_before_type_cast
+        @attributes.values_before_type_cast
+      end
+
+      private
+
+      # Handle *_before_type_cast for method_missing.
+      def attribute_before_type_cast(attribute_name)
+        read_attribute_before_type_cast(attribute_name)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
new file mode 100644
index 0000000000..b58295a106
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -0,0 +1,167 @@
+require 'active_support/core_ext/module/attribute_accessors'
+
+module ActiveRecord
+  module AttributeMethods
+    module Dirty # :nodoc:
+      extend ActiveSupport::Concern
+
+      include ActiveModel::Dirty
+
+      included do
+        if self < ::ActiveRecord::Timestamp
+          raise "You cannot include Dirty after Timestamp"
+        end
+
+        class_attribute :partial_writes, instance_writer: false
+        self.partial_writes = true
+      end
+
+      # Attempts to +save+ the record and clears changed attributes if successful.
+      def save(*)
+        if status = super
+          changes_applied
+        end
+        status
+      end
+
+      # Attempts to <tt>save!</tt> the record and clears changed attributes if successful.
+      def save!(*)
+        super.tap do
+          changes_applied
+        end
+      end
+
+      # <tt>reload</tt> the record and clears changed attributes.
+      def reload(*)
+        super.tap do
+          clear_changes_information
+        end
+      end
+
+      def initialize_dup(other) # :nodoc:
+        super
+        calculate_changes_from_defaults
+      end
+
+      def changed?
+        super || changed_in_place.any?
+      end
+
+      def changed
+        super | changed_in_place
+      end
+
+      def attribute_changed?(attr_name, options = {})
+        result = super
+        # We can't change "from" something in place. Only setters can define
+        # "from" and "to"
+        result ||= changed_in_place?(attr_name) unless options.key?(:from)
+        result
+      end
+
+      def changes_applied
+        super
+        store_original_raw_attributes
+      end
+
+      def clear_changes_information
+        super
+        original_raw_attributes.clear
+      end
+
+      private
+
+      def calculate_changes_from_defaults
+        @changed_attributes = nil
+        self.class.column_defaults.each do |attr, orig_value|
+          changed_attributes[attr] = orig_value if _field_changed?(attr, orig_value)
+        end
+      end
+
+      # Wrap write_attribute to remember original attribute value.
+      def write_attribute(attr, value)
+        attr = attr.to_s
+
+        old_value = old_attribute_value(attr)
+
+        result = super
+        store_original_raw_attribute(attr)
+        save_changed_attribute(attr, old_value)
+        result
+      end
+
+      def raw_write_attribute(attr, value)
+        attr = attr.to_s
+
+        result = super
+        original_raw_attributes[attr] = value
+        result
+      end
+
+      def save_changed_attribute(attr, old_value)
+        if attribute_changed?(attr)
+          changed_attributes.delete(attr) unless _field_changed?(attr, old_value)
+        else
+          changed_attributes[attr] = old_value if _field_changed?(attr, old_value)
+        end
+      end
+
+      def old_attribute_value(attr)
+        if attribute_changed?(attr)
+          changed_attributes[attr]
+        else
+          clone_attribute_value(:read_attribute, attr)
+        end
+      end
+
+      def _update_record(*)
+        partial_writes? ? super(keys_for_partial_write) : super
+      end
+
+      def _create_record(*)
+        partial_writes? ? super(keys_for_partial_write) : super
+      end
+
+      # Serialized attributes should always be written in case they've been
+      # changed in place.
+      def keys_for_partial_write
+        changed
+      end
+
+      def _field_changed?(attr, old_value)
+        @attributes[attr].changed_from?(old_value)
+      end
+
+      def changed_in_place
+        self.class.attribute_names.select do |attr_name|
+          changed_in_place?(attr_name)
+        end
+      end
+
+      def changed_in_place?(attr_name)
+        old_value = original_raw_attribute(attr_name)
+        @attributes[attr_name].changed_in_place_from?(old_value)
+      end
+
+      def original_raw_attribute(attr_name)
+        original_raw_attributes.fetch(attr_name) do
+          read_attribute_before_type_cast(attr_name)
+        end
+      end
+
+      def original_raw_attributes
+        @original_raw_attributes ||= {}
+      end
+
+      def store_original_raw_attribute(attr_name)
+        original_raw_attributes[attr_name] = @attributes[attr_name].value_for_database
+      end
+
+      def store_original_raw_attributes
+        attribute_names.each do |attr|
+          store_original_raw_attribute(attr)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
new file mode 100644
index 0000000000..9bd333bbac
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -0,0 +1,127 @@
+require 'set'
+
+module ActiveRecord
+  module AttributeMethods
+    module PrimaryKey
+      extend ActiveSupport::Concern
+
+      # Returns this record's primary key value wrapped in an Array if one is
+      # available.
+      def to_key
+        sync_with_transaction_state
+        key = self.id
+        [key] if key
+      end
+
+      # Returns the primary key value.
+      def id
+        if pk = self.class.primary_key
+          sync_with_transaction_state
+          read_attribute(pk)
+        end
+      end
+
+      # Sets the primary key value.
+      def id=(value)
+        sync_with_transaction_state
+        write_attribute(self.class.primary_key, value) if self.class.primary_key
+      end
+
+      # Queries the primary key value.
+      def id?
+        sync_with_transaction_state
+        query_attribute(self.class.primary_key)
+      end
+
+      # Returns the primary key value before type cast.
+      def id_before_type_cast
+        sync_with_transaction_state
+        read_attribute_before_type_cast(self.class.primary_key)
+      end
+
+      # Returns the primary key previous value.
+      def id_was
+        sync_with_transaction_state
+        attribute_was(self.class.primary_key)
+      end
+
+      protected
+
+      def attribute_method?(attr_name)
+        attr_name == 'id' || super
+      end
+
+      module ClassMethods
+        def define_method_attribute(attr_name)
+          super
+
+          if attr_name == primary_key && attr_name != 'id'
+            generated_attribute_methods.send(:alias_method, :id, primary_key)
+          end
+        end
+
+        ID_ATTRIBUTE_METHODS = %w(id id= id? id_before_type_cast id_was).to_set
+
+        def dangerous_attribute_method?(method_name)
+          super && !ID_ATTRIBUTE_METHODS.include?(method_name)
+        end
+
+        # Defines the primary key field -- can be overridden in subclasses.
+        # Overwriting will negate any effect of the +primary_key_prefix_type+
+        # setting, though.
+        def primary_key
+          @primary_key = reset_primary_key unless defined? @primary_key
+          @primary_key
+        end
+
+        # Returns a quoted version of the primary key name, used to construct
+        # SQL statements.
+        def quoted_primary_key
+          @quoted_primary_key ||= connection.quote_column_name(primary_key)
+        end
+
+        def reset_primary_key #:nodoc:
+          if self == base_class
+            self.primary_key = get_primary_key(base_class.name)
+          else
+            self.primary_key = base_class.primary_key
+          end
+        end
+
+        def get_primary_key(base_name) #:nodoc:
+          if base_name && primary_key_prefix_type == :table_name
+            base_name.foreign_key(false)
+          elsif base_name && primary_key_prefix_type == :table_name_with_underscore
+            base_name.foreign_key
+          else
+            if ActiveRecord::Base != self && table_exists?
+              connection.schema_cache.primary_keys(table_name)
+            else
+              'id'
+            end
+          end
+        end
+
+        # Sets the name of the primary key column.
+        #
+        #   class Project < ActiveRecord::Base
+        #     self.primary_key = 'sysid'
+        #   end
+        #
+        # You can also define the +primary_key+ method yourself:
+        #
+        #   class Project < ActiveRecord::Base
+        #     def self.primary_key
+        #       'foo_' + super
+        #     end
+        #   end
+        #
+        #   Project.primary_key # => "foo_id"
+        def primary_key=(value)
+          @primary_key        = value && value.to_s
+          @quoted_primary_key = nil
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/query.rb b/activerecord/lib/active_record/attribute_methods/query.rb
new file mode 100644
index 0000000000..0f9723febb
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/query.rb
@@ -0,0 +1,40 @@
+module ActiveRecord
+  module AttributeMethods
+    module Query
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "?"
+      end
+
+      def query_attribute(attr_name)
+        value = read_attribute(attr_name) { |n| missing_attribute(n, caller) }
+
+        case value
+        when true        then true
+        when false, nil  then false
+        else
+          column = self.class.columns_hash[attr_name]
+          if column.nil?
+            if Numeric === value || value !~ /[^0-9]/
+              !value.to_i.zero?
+            else
+              return false if ActiveRecord::ConnectionAdapters::Column::FALSE_VALUES.include?(value)
+              !value.blank?
+            end
+          elsif column.number?
+            !value.zero?
+          else
+            !value.blank?
+          end
+        end
+      end
+
+      private
+        # Handle *? for method_missing.
+        def attribute?(attribute_name)
+          query_attribute(attribute_name)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
new file mode 100644
index 0000000000..10869dfc1e
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -0,0 +1,97 @@
+require 'active_support/core_ext/module/method_transplanting'
+
+module ActiveRecord
+  module AttributeMethods
+    module Read
+      ReaderMethodCache = Class.new(AttributeMethodCache) {
+        private
+        # We want to generate the methods via module_eval rather than
+        # define_method, because define_method is slower on dispatch.
+        # Evaluating many similar methods may use more memory as the instruction
+        # sequences are duplicated and cached (in MRI).  define_method may
+        # be slower on dispatch, but if you're careful about the closure
+        # created, then define_method will consume much less memory.
+        #
+        # But sometimes the database might return columns with
+        # characters that are not allowed in normal method names (like
+        # 'my_column(omg)'. So to work around this we first define with
+        # the __temp__ identifier, and then use alias method to rename
+        # it to what we want.
+        #
+        # We are also defining a constant to hold the frozen string of
+        # the attribute name. Using a constant means that we do not have
+        # to allocate an object on each call to the attribute method.
+        # Making it frozen means that it doesn't get duped when used to
+        # key the @attributes in read_attribute.
+        def method_body(method_name, const_name)
+          <<-EOMETHOD
+          def #{method_name}
+            name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{const_name}
+            read_attribute(name) { |n| missing_attribute(n, caller) }
+          end
+          EOMETHOD
+        end
+      }.new
+
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        [:cache_attributes, :cached_attributes, :cache_attribute?].each do |method_name|
+          define_method method_name do |*|
+            cached_attributes_deprecation_warning(method_name)
+            true
+          end
+        end
+
+        protected
+
+        def cached_attributes_deprecation_warning(method_name)
+          ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
+            Calling `#{method_name}` is no longer necessary. All attributes are cached.
+          MESSAGE
+        end
+
+        if Module.methods_transplantable?
+          def define_method_attribute(name)
+            method = ReaderMethodCache[name]
+            generated_attribute_methods.module_eval { define_method name, method }
+          end
+        else
+          def define_method_attribute(name)
+            safe_name = name.unpack('h*').first
+            temp_method = "__temp__#{safe_name}"
+
+            ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+
+            generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+              def #{temp_method}
+                name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name}
+                read_attribute(name) { |n| missing_attribute(n, caller) }
+              end
+            STR
+
+            generated_attribute_methods.module_eval do
+              alias_method name, temp_method
+              undef_method temp_method
+            end
+          end
+        end
+      end
+
+      # Returns the value of the attribute identified by <tt>attr_name</tt> after
+      # it has been typecast (for example, "2004-12-12" in a date column is cast
+      # to a date object, like Date.new(2004, 12, 12)).
+      def read_attribute(attr_name, &block)
+        name = attr_name.to_s
+        name = self.class.primary_key if name == 'id'
+        @attributes.fetch_value(name, &block)
+      end
+
+      private
+
+      def attribute(attribute_name)
+        read_attribute(attribute_name)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/serialization.rb b/activerecord/lib/active_record/attribute_methods/serialization.rb
new file mode 100644
index 0000000000..264ce2bdfa
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/serialization.rb
@@ -0,0 +1,70 @@
+module ActiveRecord
+  module AttributeMethods
+    module Serialization
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        # If you have an attribute that needs to be saved to the database as an
+        # object, and retrieved as the same object, then specify the name of that
+        # attribute using this method and it will be handled automatically. The
+        # serialization is done through YAML. If +class_name+ is specified, the
+        # serialized object must be of that class on retrieval or
+        # <tt>SerializationTypeMismatch</tt> will be raised.
+        #
+        # A notable side effect of serialized attributes is that the model will
+        # be updated on every save, even if it is not dirty.
+        #
+        # ==== Parameters
+        #
+        # * +attr_name+ - The field name that should be serialized.
+        # * +class_name_or_coder+ - Optional, a coder object, which responds to `.load` / `.dump`
+        #   or a class name that the object type should be equal to.
+        #
+        # ==== Example
+        #
+        #   # Serialize a preferences attribute.
+        #   class User < ActiveRecord::Base
+        #     serialize :preferences
+        #   end
+        #
+        #   # Serialize preferences using JSON as coder.
+        #   class User < ActiveRecord::Base
+        #     serialize :preferences, JSON
+        #   end
+        #
+        #   # Serialize preferences as Hash using YAML coder.
+        #   class User < ActiveRecord::Base
+        #     serialize :preferences, Hash
+        #   end
+        def serialize(attr_name, class_name_or_coder = Object)
+          # When ::JSON is used, force it to go through the Active Support JSON encoder
+          # to ensure special objects (e.g. Active Record models) are dumped correctly
+          # using the #as_json hook.
+          coder = if class_name_or_coder == ::JSON
+                    Coders::JSON
+                  elsif [:load, :dump].all? { |x| class_name_or_coder.respond_to?(x) }
+                    class_name_or_coder
+                  else
+                    Coders::YAMLColumn.new(class_name_or_coder)
+                  end
+
+          decorate_attribute_type(attr_name, :serialize) do |type|
+            Type::Serialized.new(type, coder)
+          end
+        end
+
+        def serialized_attributes
+          ActiveSupport::Deprecation.warn(<<-WARNING.strip_heredoc)
+            `serialized_attributes` is deprecated without replacement, and will
+            be removed in Rails 5.0.
+          WARNING
+          @serialized_attributes ||= Hash[
+            columns.select { |t| t.cast_type.is_a?(Type::Serialized) }.map { |c|
+              [c.name, c.cast_type.coder]
+            }
+          ]
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
new file mode 100644
index 0000000000..f439bd1ffe
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -0,0 +1,63 @@
+module ActiveRecord
+  module AttributeMethods
+    module TimeZoneConversion
+      class TimeZoneConverter < SimpleDelegator # :nodoc:
+        def type_cast_from_database(value)
+          convert_time_to_time_zone(super)
+        end
+
+        def type_cast_from_user(value)
+          if value.is_a?(Array)
+            value.map { |v| type_cast_from_user(v) }
+          elsif value.respond_to?(:in_time_zone)
+            value.in_time_zone
+          end
+        end
+
+        def convert_time_to_time_zone(value)
+          if value.is_a?(Array)
+            value.map { |v| convert_time_to_time_zone(v) }
+          elsif value.acts_like?(:time)
+            value.in_time_zone
+          else
+            value
+          end
+        end
+      end
+
+      extend ActiveSupport::Concern
+
+      included do
+        mattr_accessor :time_zone_aware_attributes, instance_writer: false
+        self.time_zone_aware_attributes = false
+
+        class_attribute :skip_time_zone_conversion_for_attributes, instance_writer: false
+        self.skip_time_zone_conversion_for_attributes = []
+      end
+
+      module ClassMethods
+        private
+
+        def inherited(subclass)
+          # We need to apply this decorator here, rather than on module inclusion. The closure
+          # created by the matcher would otherwise evaluate for `ActiveRecord::Base`, not the
+          # sub class being decorated. As such, changes to `time_zone_aware_attributes`, or
+          # `skip_time_zone_conversion_for_attributes` would not be picked up.
+          subclass.class_eval do
+            matcher = ->(name, type) { create_time_zone_conversion_attribute?(name, type) }
+            decorate_matching_attribute_types(matcher, :_time_zone_conversion) do |type|
+              TimeZoneConverter.new(type)
+            end
+          end
+          super
+        end
+
+        def create_time_zone_conversion_attribute?(name, cast_type)
+          time_zone_aware_attributes &&
+            !self.skip_time_zone_conversion_for_attributes.include?(name.to_sym) &&
+            (:datetime == cast_type.type)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
new file mode 100644
index 0000000000..b3c8209a74
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -0,0 +1,83 @@
+require 'active_support/core_ext/module/method_transplanting'
+
+module ActiveRecord
+  module AttributeMethods
+    module Write
+      WriterMethodCache = Class.new(AttributeMethodCache) {
+        private
+
+        def method_body(method_name, const_name)
+          <<-EOMETHOD
+          def #{method_name}(value)
+            name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{const_name}
+            write_attribute(name, value)
+          end
+          EOMETHOD
+        end
+      }.new
+
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "="
+      end
+
+      module ClassMethods
+        protected
+
+        if Module.methods_transplantable?
+          def define_method_attribute=(name)
+            method = WriterMethodCache[name]
+            generated_attribute_methods.module_eval {
+              define_method "#{name}=", method
+            }
+          end
+        else
+          def define_method_attribute=(name)
+            safe_name = name.unpack('h*').first
+            ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+
+            generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+              def __temp__#{safe_name}=(value)
+                name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name}
+                write_attribute(name, value)
+              end
+              alias_method #{(name + '=').inspect}, :__temp__#{safe_name}=
+              undef_method :__temp__#{safe_name}=
+            STR
+          end
+        end
+      end
+
+      # Updates the attribute identified by <tt>attr_name</tt> with the
+      # specified +value+. Empty strings for fixnum and float columns are
+      # turned into +nil+.
+      def write_attribute(attr_name, value)
+        write_attribute_with_type_cast(attr_name, value, true)
+      end
+
+      def raw_write_attribute(attr_name, value)
+        write_attribute_with_type_cast(attr_name, value, false)
+      end
+
+      private
+      # Handle *= for method_missing.
+      def attribute=(attribute_name, value)
+        write_attribute(attribute_name, value)
+      end
+
+      def write_attribute_with_type_cast(attr_name, value, should_type_cast)
+        attr_name = attr_name.to_s
+        attr_name = self.class.primary_key if attr_name == 'id' && self.class.primary_key
+
+        if should_type_cast
+          @attributes.write_from_user(attr_name, value)
+        else
+          @attributes.write_from_database(attr_name, value)
+        end
+
+        value
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_set.rb b/activerecord/lib/active_record/attribute_set.rb
new file mode 100644
index 0000000000..98ac63c7e1
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_set.rb
@@ -0,0 +1,77 @@
+require 'active_record/attribute_set/builder'
+
+module ActiveRecord
+  class AttributeSet # :nodoc:
+    delegate :keys, to: :initialized_attributes
+
+    def initialize(attributes)
+      @attributes = attributes
+    end
+
+    def [](name)
+      attributes[name] || Attribute.null(name)
+    end
+
+    def values_before_type_cast
+      attributes.transform_values(&:value_before_type_cast)
+    end
+
+    def to_hash
+      initialized_attributes.transform_values(&:value)
+    end
+    alias_method :to_h, :to_hash
+
+    def key?(name)
+      attributes.key?(name) && self[name].initialized?
+    end
+
+    def fetch_value(name, &block)
+      self[name].value(&block)
+    end
+
+    def write_from_database(name, value)
+      attributes[name] = self[name].with_value_from_database(value)
+    end
+
+    def write_from_user(name, value)
+      attributes[name] = self[name].with_value_from_user(value)
+    end
+
+    def freeze
+      @attributes.freeze
+      super
+    end
+
+    def initialize_dup(_)
+      @attributes = attributes.transform_values(&:dup)
+      super
+    end
+
+    def initialize_clone(_)
+      @attributes = attributes.clone
+      super
+    end
+
+    def reset(key)
+      if key?(key)
+        write_from_database(key, nil)
+      end
+    end
+
+    def ensure_initialized(key)
+      unless self[key].initialized?
+        write_from_database(key, nil)
+      end
+    end
+
+    protected
+
+    attr_reader :attributes
+
+    private
+
+    def initialized_attributes
+      attributes.select { |_, attr| attr.initialized? }
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_set/builder.rb b/activerecord/lib/active_record/attribute_set/builder.rb
new file mode 100644
index 0000000000..1e146a07da
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_set/builder.rb
@@ -0,0 +1,32 @@
+module ActiveRecord
+  class AttributeSet # :nodoc:
+    class Builder # :nodoc:
+      attr_reader :types
+
+      def initialize(types)
+        @types = types
+      end
+
+      def build_from_database(values = {}, additional_types = {})
+        attributes = build_attributes_from_values(values, additional_types)
+        add_uninitialized_attributes(attributes)
+        AttributeSet.new(attributes)
+      end
+
+      private
+
+      def build_attributes_from_values(values, additional_types)
+        values.each_with_object({}) do |(name, value), hash|
+          type = additional_types.fetch(name, types[name])
+          hash[name] = Attribute.from_database(name, value, type)
+        end
+      end
+
+      def add_uninitialized_attributes(attributes)
+        types.except(*attributes.keys).each do |name, type|
+          attributes[name] = Attribute.uninitialized(name, type)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attributes.rb b/activerecord/lib/active_record/attributes.rb
new file mode 100644
index 0000000000..890a1314d9
--- /dev/null
+++ b/activerecord/lib/active_record/attributes.rb
@@ -0,0 +1,122 @@
+module ActiveRecord
+  module Attributes # :nodoc:
+    extend ActiveSupport::Concern
+
+    Type = ActiveRecord::Type
+
+    included do
+      class_attribute :user_provided_columns, instance_accessor: false # :internal:
+      self.user_provided_columns = {}
+    end
+
+    module ClassMethods # :nodoc:
+      # Defines or overrides a attribute on this model. This allows customization of
+      # Active Record's type casting behavior, as well as adding support for user defined
+      # types.
+      #
+      # +name+ The name of the methods to define attribute methods for, and the column which
+      # this will persist to.
+      #
+      # +cast_type+ A type object that contains information about how to type cast the value.
+      # See the examples section for more information.
+      #
+      # ==== Options
+      # The options hash accepts the following options:
+      #
+      # +default+ is the default value that the column should use on a new record.
+      #
+      # ==== Examples
+      #
+      # The type detected by Active Record can be overridden.
+      #
+      #   # db/schema.rb
+      #   create_table :store_listings, force: true do |t|
+      #     t.decimal :price_in_cents
+      #   end
+      #
+      #   # app/models/store_listing.rb
+      #   class StoreListing < ActiveRecord::Base
+      #   end
+      #
+      #   store_listing = StoreListing.new(price_in_cents: '10.1')
+      #
+      #   # before
+      #   store_listing.price_in_cents # => BigDecimal.new(10.1)
+      #
+      #   class StoreListing < ActiveRecord::Base
+      #     attribute :price_in_cents, Type::Integer.new
+      #   end
+      #
+      #   # after
+      #   store_listing.price_in_cents # => 10
+      #
+      # Users may also define their own custom types, as long as they respond to the methods
+      # defined on the value type. The `type_cast` method on your type object will be called
+      # with values both from the database, and from your controllers. See
+      # `ActiveRecord::Attributes::Type::Value` for the expected API. It is recommended that your
+      # type objects inherit from an existing type, or the base value type.
+      #
+      #   class MoneyType < ActiveRecord::Type::Integer
+      #     def type_cast(value)
+      #       if value.include?('$')
+      #         price_in_dollars = value.gsub(/\$/, '').to_f
+      #         price_in_dollars * 100
+      #       else
+      #         value.to_i
+      #       end
+      #     end
+      #   end
+      #
+      #   class StoreListing < ActiveRecord::Base
+      #     attribute :price_in_cents, MoneyType.new
+      #   end
+      #
+      #   store_listing = StoreListing.new(price_in_cents: '$10.00')
+      #   store_listing.price_in_cents # => 1000
+      def attribute(name, cast_type, options = {})
+        name = name.to_s
+        clear_caches_calculated_from_columns
+        # Assign a new hash to ensure that subclasses do not share a hash
+        self.user_provided_columns = user_provided_columns.merge(name => connection.new_column(name, options[:default], cast_type))
+      end
+
+      # Returns an array of column objects for the table associated with this class.
+      def columns
+        @columns ||= add_user_provided_columns(connection.schema_cache.columns(table_name))
+      end
+
+      # Returns a hash of column objects for the table associated with this class.
+      def columns_hash
+        @columns_hash ||= Hash[columns.map { |c| [c.name, c] }]
+      end
+
+      def reset_column_information # :nodoc:
+        super
+        clear_caches_calculated_from_columns
+      end
+
+      private
+
+      def add_user_provided_columns(schema_columns)
+        existing_columns = schema_columns.map do |column|
+          user_provided_columns[column.name] || column
+        end
+
+        existing_column_names = existing_columns.map(&:name)
+        new_columns = user_provided_columns.except(*existing_column_names).values
+
+        existing_columns + new_columns
+      end
+
+      def clear_caches_calculated_from_columns
+        @attributes_builder = nil
+        @column_names = nil
+        @column_types = nil
+        @columns = nil
+        @columns_hash = nil
+        @content_columns = nil
+        @default_attributes = nil
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
new file mode 100644
index 0000000000..dd92e29199
--- /dev/null
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -0,0 +1,437 @@
+module ActiveRecord
+  # = Active Record Autosave Association
+  #
+  # +AutosaveAssociation+ is a module that takes care of automatically saving
+  # associated records when their parent is saved. In addition to saving, it
+  # also destroys any associated records that were marked for destruction.
+  # (See +mark_for_destruction+ and <tt>marked_for_destruction?</tt>).
+  #
+  # Saving of the parent, its associations, and the destruction of marked
+  # associations, all happen inside a transaction. This should never leave the
+  # database in an inconsistent state.
+  #
+  # If validations for any of the associations fail, their error messages will
+  # be applied to the parent.
+  #
+  # Note that it also means that associations marked for destruction won't
+  # be destroyed directly. They will however still be marked for destruction.
+  #
+  # Note that <tt>autosave: false</tt> is not same as not declaring <tt>:autosave</tt>.
+  # When the <tt>:autosave</tt> option is not present then new association records are
+  # saved but the updated association records are not saved.
+  #
+  # == Validation
+  #
+  # Children records are validated unless <tt>:validate</tt> is +false+.
+  #
+  # == Callbacks
+  #
+  # Association with autosave option defines several callbacks on your
+  # model (before_save, after_create, after_update). Please note that
+  # callbacks are executed in the order they were defined in
+  # model. You should avoid modifying the association content, before
+  # autosave callbacks are executed. Placing your callbacks after
+  # associations is usually a good practice.
+  #
+  # === One-to-one Example
+  #
+  #   class Post < ActiveRecord::Base
+  #     has_one :author, autosave: true
+  #   end
+  #
+  # Saving changes to the parent and its associated model can now be performed
+  # automatically _and_ atomically:
+  #
+  #   post = Post.find(1)
+  #   post.title       # => "The current global position of migrating ducks"
+  #   post.author.name # => "alloy"
+  #
+  #   post.title = "On the migration of ducks"
+  #   post.author.name = "Eloy Duran"
+  #
+  #   post.save
+  #   post.reload
+  #   post.title       # => "On the migration of ducks"
+  #   post.author.name # => "Eloy Duran"
+  #
+  # Destroying an associated model, as part of the parent's save action, is as
+  # simple as marking it for destruction:
+  #
+  #   post.author.mark_for_destruction
+  #   post.author.marked_for_destruction? # => true
+  #
+  # Note that the model is _not_ yet removed from the database:
+  #
+  #   id = post.author.id
+  #   Author.find_by(id: id).nil? # => false
+  #
+  #   post.save
+  #   post.reload.author # => nil
+  #
+  # Now it _is_ removed from the database:
+  #
+  #   Author.find_by(id: id).nil? # => true
+  #
+  # === One-to-many Example
+  #
+  # When <tt>:autosave</tt> is not declared new children are saved when their parent is saved:
+  #
+  #   class Post < ActiveRecord::Base
+  #     has_many :comments # :autosave option is not declared
+  #   end
+  #
+  #   post = Post.new(title: 'ruby rocks')
+  #   post.comments.build(body: 'hello world')
+  #   post.save # => saves both post and comment
+  #
+  #   post = Post.create(title: 'ruby rocks')
+  #   post.comments.build(body: 'hello world')
+  #   post.save # => saves both post and comment
+  #
+  #   post = Post.create(title: 'ruby rocks')
+  #   post.comments.create(body: 'hello world')
+  #   post.save # => saves both post and comment
+  #
+  # When <tt>:autosave</tt> is true all children are saved, no matter whether they
+  # are new records or not:
+  #
+  #   class Post < ActiveRecord::Base
+  #     has_many :comments, autosave: true
+  #   end
+  #
+  #   post = Post.create(title: 'ruby rocks')
+  #   post.comments.create(body: 'hello world')
+  #   post.comments[0].body = 'hi everyone'
+  #   post.comments.build(body: "good morning.")
+  #   post.title += "!"
+  #   post.save # => saves both post and comments.
+  #
+  # Destroying one of the associated models as part of the parent's save action
+  # is as simple as marking it for destruction:
+  #
+  #   post.comments # => [#<Comment id: 1, ...>, #<Comment id: 2, ...]>
+  #   post.comments[1].mark_for_destruction
+  #   post.comments[1].marked_for_destruction? # => true
+  #   post.comments.length # => 2
+  #
+  # Note that the model is _not_ yet removed from the database:
+  #
+  #   id = post.comments.last.id
+  #   Comment.find_by(id: id).nil? # => false
+  #
+  #   post.save
+  #   post.reload.comments.length # => 1
+  #
+  # Now it _is_ removed from the database:
+  #
+  #   Comment.find_by(id: id).nil? # => true
+
+  module AutosaveAssociation
+    extend ActiveSupport::Concern
+
+    module AssociationBuilderExtension #:nodoc:
+      def self.build(model, reflection)
+        model.send(:add_autosave_association_callbacks, reflection)
+      end
+
+      def self.valid_options
+        [ :autosave ]
+      end
+    end
+
+    included do
+      Associations::Builder::Association.extensions << AssociationBuilderExtension
+    end
+
+    module ClassMethods
+      private
+
+        def define_non_cyclic_method(name, &block)
+          return if method_defined?(name)
+          define_method(name) do |*args|
+            result = true; @_already_called ||= {}
+            # Loop prevention for validation of associations
+            unless @_already_called[name]
+              begin
+                @_already_called[name]=true
+                result = instance_eval(&block)
+              ensure
+                @_already_called[name]=false
+              end
+            end
+
+            result
+          end
+        end
+
+        # Adds validation and save callbacks for the association as specified by
+        # the +reflection+.
+        #
+        # For performance reasons, we don't check whether to validate at runtime.
+        # However the validation and callback methods are lazy and those methods
+        # get created when they are invoked for the very first time. However,
+        # this can change, for instance, when using nested attributes, which is
+        # called _after_ the association has been defined. Since we don't want
+        # the callbacks to get defined multiple times, there are guards that
+        # check if the save or validation methods have already been defined
+        # before actually defining them.
+        def add_autosave_association_callbacks(reflection)
+          save_method = :"autosave_associated_records_for_#{reflection.name}"
+          validation_method = :"validate_associated_records_for_#{reflection.name}"
+          collection = reflection.collection?
+
+          if collection
+            before_save :before_save_collection_association
+
+            define_non_cyclic_method(save_method) { save_collection_association(reflection) }
+            after_save save_method
+          elsif reflection.has_one?
+            define_method(save_method) { save_has_one_association(reflection) } unless method_defined?(save_method)
+            # Configures two callbacks instead of a single after_save so that
+            # the model may rely on their execution order relative to its
+            # own callbacks.
+            #
+            # For example, given that after_creates run before after_saves, if
+            # we configured instead an after_save there would be no way to fire
+            # a custom after_create callback after the child association gets
+            # created.
+            after_create save_method
+            after_update save_method
+          else
+            define_non_cyclic_method(save_method) { save_belongs_to_association(reflection) }
+            before_save save_method
+          end
+
+          if reflection.validate? && !method_defined?(validation_method)
+            method = (collection ? :validate_collection_association : :validate_single_association)
+            define_non_cyclic_method(validation_method) { send(method, reflection) }
+            validate validation_method
+          end
+        end
+    end
+
+    # Reloads the attributes of the object as usual and clears <tt>marked_for_destruction</tt> flag.
+    def reload(options = nil)
+      @marked_for_destruction = false
+      @destroyed_by_association = nil
+      super
+    end
+
+    # Marks this record to be destroyed as part of the parents save transaction.
+    # This does _not_ actually destroy the record instantly, rather child record will be destroyed
+    # when <tt>parent.save</tt> is called.
+    #
+    # Only useful if the <tt>:autosave</tt> option on the parent is enabled for this associated model.
+    def mark_for_destruction
+      @marked_for_destruction = true
+    end
+
+    # Returns whether or not this record will be destroyed as part of the parents save transaction.
+    #
+    # Only useful if the <tt>:autosave</tt> option on the parent is enabled for this associated model.
+    def marked_for_destruction?
+      @marked_for_destruction
+    end
+
+    # Records the association that is being destroyed and destroying this
+    # record in the process.
+    def destroyed_by_association=(reflection)
+      @destroyed_by_association = reflection
+    end
+
+    # Returns the association for the parent being destroyed.
+    #
+    # Used to avoid updating the counter cache unnecessarily.
+    def destroyed_by_association
+      @destroyed_by_association
+    end
+
+    # Returns whether or not this record has been changed in any way (including whether
+    # any of its nested autosave associations are likewise changed)
+    def changed_for_autosave?
+      new_record? || changed? || marked_for_destruction? || nested_records_changed_for_autosave?
+    end
+
+    private
+
+      # Returns the record for an association collection that should be validated
+      # or saved. If +autosave+ is +false+ only new records will be returned,
+      # unless the parent is/was a new record itself.
+      def associated_records_to_validate_or_save(association, new_record, autosave)
+        if new_record
+          association && association.target
+        elsif autosave
+          association.target.find_all { |record| record.changed_for_autosave? }
+        else
+          association.target.find_all { |record| record.new_record? }
+        end
+      end
+
+      # go through nested autosave associations that are loaded in memory (without loading
+      # any new ones), and return true if is changed for autosave
+      def nested_records_changed_for_autosave?
+        self.class._reflections.values.any? do |reflection|
+          if reflection.options[:autosave]
+            association = association_instance_get(reflection.name)
+            association && Array.wrap(association.target).any? { |a| a.changed_for_autosave? }
+          end
+        end
+      end
+
+      # Validate the association if <tt>:validate</tt> or <tt>:autosave</tt> is
+      # turned on for the association.
+      def validate_single_association(reflection)
+        association = association_instance_get(reflection.name)
+        record      = association && association.reader
+        association_valid?(reflection, record) if record
+      end
+
+      # Validate the associated records if <tt>:validate</tt> or
+      # <tt>:autosave</tt> is turned on for the association specified by
+      # +reflection+.
+      def validate_collection_association(reflection)
+        if association = association_instance_get(reflection.name)
+          if records = associated_records_to_validate_or_save(association, new_record?, reflection.options[:autosave])
+            records.each { |record| association_valid?(reflection, record) }
+          end
+        end
+      end
+
+      # Returns whether or not the association is valid and applies any errors to
+      # the parent, <tt>self</tt>, if it wasn't. Skips any <tt>:autosave</tt>
+      # enabled records if they're marked_for_destruction? or destroyed.
+      def association_valid?(reflection, record)
+        return true if record.destroyed? || record.marked_for_destruction?
+
+        validation_context = self.validation_context unless [:create, :update].include?(self.validation_context)
+        unless valid = record.valid?(validation_context)
+          if reflection.options[:autosave]
+            record.errors.each do |attribute, message|
+              attribute = "#{reflection.name}.#{attribute}"
+              errors[attribute] << message
+              errors[attribute].uniq!
+            end
+          else
+            errors.add(reflection.name)
+          end
+        end
+        valid
+      end
+
+      # Is used as a before_save callback to check while saving a collection
+      # association whether or not the parent was a new record before saving.
+      def before_save_collection_association
+        @new_record_before_save = new_record?
+        true
+      end
+
+      # Saves any new associated records, or all loaded autosave associations if
+      # <tt>:autosave</tt> is enabled on the association.
+      #
+      # In addition, it destroys all children that were marked for destruction
+      # with mark_for_destruction.
+      #
+      # This all happens inside a transaction, _if_ the Transactions module is included into
+      # ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
+      def save_collection_association(reflection)
+        if association = association_instance_get(reflection.name)
+          autosave = reflection.options[:autosave]
+
+          if records = associated_records_to_validate_or_save(association, @new_record_before_save, autosave)
+
+            if autosave
+              records_to_destroy = records.select(&:marked_for_destruction?)
+              records_to_destroy.each { |record| association.destroy(record) }
+              records -= records_to_destroy
+            end
+
+            records.each do |record|
+              next if record.destroyed?
+
+              saved = true
+
+              if autosave != false && (@new_record_before_save || record.new_record?)
+                if autosave
+                  saved = association.insert_record(record, false)
+                else
+                  association.insert_record(record) unless reflection.nested?
+                end
+              elsif autosave
+                saved = record.save(:validate => false)
+              end
+
+              raise ActiveRecord::Rollback unless saved
+            end
+            @new_record_before_save = false
+          end
+
+          # reconstruct the scope now that we know the owner's id
+          association.reset_scope if association.respond_to?(:reset_scope)
+        end
+      end
+
+      # Saves the associated record if it's new or <tt>:autosave</tt> is enabled
+      # on the association.
+      #
+      # In addition, it will destroy the association if it was marked for
+      # destruction with mark_for_destruction.
+      #
+      # This all happens inside a transaction, _if_ the Transactions module is included into
+      # ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
+      def save_has_one_association(reflection)
+        association = association_instance_get(reflection.name)
+        record      = association && association.load_target
+
+        if record && !record.destroyed?
+          autosave = reflection.options[:autosave]
+
+          if autosave && record.marked_for_destruction?
+            record.destroy
+          elsif autosave != false
+            key = reflection.options[:primary_key] ? send(reflection.options[:primary_key]) : id
+
+            if (autosave && record.changed_for_autosave?) || new_record? || record_changed?(reflection, record, key)
+              unless reflection.through_reflection
+                record[reflection.foreign_key] = key
+              end
+
+              saved = record.save(:validate => !autosave)
+              raise ActiveRecord::Rollback if !saved && autosave
+              saved
+            end
+          end
+        end
+      end
+
+      # If the record is new or it has changed, returns true.
+      def record_changed?(reflection, record, key)
+        record.new_record? || record[reflection.foreign_key] != key || record.attribute_changed?(reflection.foreign_key)
+      end
+
+      # Saves the associated record if it's new or <tt>:autosave</tt> is enabled.
+      #
+      # In addition, it will destroy the association if it was marked for destruction.
+      def save_belongs_to_association(reflection)
+        association = association_instance_get(reflection.name)
+        record      = association && association.load_target
+        if record && !record.destroyed?
+          autosave = reflection.options[:autosave]
+
+          if autosave && record.marked_for_destruction?
+            self[reflection.foreign_key] = nil
+            record.destroy
+          elsif autosave != false
+            saved = record.save(:validate => !autosave) if record.new_record? || (autosave && record.changed_for_autosave?)
+
+            if association.updated?
+              association_id = record.send(reflection.options[:primary_key] || :id)
+              self[reflection.foreign_key] = association_id
+              association.loaded!
+            end
+
+            saved if autosave
+          end
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
new file mode 100644
index 0000000000..f978fbd0a4
--- /dev/null
+++ b/activerecord/lib/active_record/base.rb
@@ -0,0 +1,317 @@
+require 'yaml'
+require 'set'
+require 'active_support/benchmarkable'
+require 'active_support/dependencies'
+require 'active_support/descendants_tracker'
+require 'active_support/time'
+require 'active_support/core_ext/module/attribute_accessors'
+require 'active_support/core_ext/class/delegating_attributes'
+require 'active_support/core_ext/array/extract_options'
+require 'active_support/core_ext/hash/deep_merge'
+require 'active_support/core_ext/hash/slice'
+require 'active_support/core_ext/hash/transform_values'
+require 'active_support/core_ext/string/behavior'
+require 'active_support/core_ext/kernel/singleton_class'
+require 'active_support/core_ext/module/introspection'
+require 'active_support/core_ext/object/duplicable'
+require 'active_support/core_ext/class/subclasses'
+require 'arel'
+require 'active_record/attribute_decorators'
+require 'active_record/errors'
+require 'active_record/log_subscriber'
+require 'active_record/explain_subscriber'
+require 'active_record/relation/delegation'
+require 'active_record/attributes'
+
+module ActiveRecord #:nodoc:
+  # = Active Record
+  #
+  # Active Record objects don't specify their attributes directly, but rather infer them from
+  # the table definition with which they're linked. Adding, removing, and changing attributes
+  # and their type is done directly in the database. Any change is instantly reflected in the
+  # Active Record objects. The mapping that binds a given Active Record class to a certain
+  # database table will happen automatically in most common cases, but can be overwritten for the uncommon ones.
+  #
+  # See the mapping rules in table_name and the full example in link:files/activerecord/README_rdoc.html for more insight.
+  #
+  # == Creation
+  #
+  # Active Records accept constructor parameters either in a hash or as a block. The hash
+  # method is especially useful when you're receiving the data from somewhere else, like an
+  # HTTP request. It works like this:
+  #
+  #   user = User.new(name: "David", occupation: "Code Artist")
+  #   user.name # => "David"
+  #
+  # You can also use block initialization:
+  #
+  #   user = User.new do |u|
+  #     u.name = "David"
+  #     u.occupation = "Code Artist"
+  #   end
+  #
+  # And of course you can just create a bare object and specify the attributes after the fact:
+  #
+  #   user = User.new
+  #   user.name = "David"
+  #   user.occupation = "Code Artist"
+  #
+  # == Conditions
+  #
+  # Conditions can either be specified as a string, array, or hash representing the WHERE-part of an SQL statement.
+  # The array form is to be used when the condition input is tainted and requires sanitization. The string form can
+  # be used for statements that don't involve tainted data. The hash form works much like the array form, except
+  # only equality and range is possible. Examples:
+  #
+  #   class User < ActiveRecord::Base
+  #     def self.authenticate_unsafely(user_name, password)
+  #       where("user_name = '#{user_name}' AND password = '#{password}'").first
+  #     end
+  #
+  #     def self.authenticate_safely(user_name, password)
+  #       where("user_name = ? AND password = ?", user_name, password).first
+  #     end
+  #
+  #     def self.authenticate_safely_simply(user_name, password)
+  #       where(user_name: user_name, password: password).first
+  #     end
+  #   end
+  #
+  # The <tt>authenticate_unsafely</tt> method inserts the parameters directly into the query
+  # and is thus susceptible to SQL-injection attacks if the <tt>user_name</tt> and +password+
+  # parameters come directly from an HTTP request. The <tt>authenticate_safely</tt> and
+  # <tt>authenticate_safely_simply</tt> both will sanitize the <tt>user_name</tt> and +password+
+  # before inserting them in the query, which will ensure that an attacker can't escape the
+  # query and fake the login (or worse).
+  #
+  # When using multiple parameters in the conditions, it can easily become hard to read exactly
+  # what the fourth or fifth question mark is supposed to represent. In those cases, you can
+  # resort to named bind variables instead. That's done by replacing the question marks with
+  # symbols and supplying a hash with values for the matching symbol keys:
+  #
+  #   Company.where(
+  #     "id = :id AND name = :name AND division = :division AND created_at > :accounting_date",
+  #     { id: 3, name: "37signals", division: "First", accounting_date: '2005-01-01' }
+  #   ).first
+  #
+  # Similarly, a simple hash without a statement will generate conditions based on equality with the SQL AND
+  # operator. For instance:
+  #
+  #   Student.where(first_name: "Harvey", status: 1)
+  #   Student.where(params[:student])
+  #
+  # A range may be used in the hash to use the SQL BETWEEN operator:
+  #
+  #   Student.where(grade: 9..12)
+  #
+  # An array may be used in the hash to use the SQL IN operator:
+  #
+  #   Student.where(grade: [9,11,12])
+  #
+  # When joining tables, nested hashes or keys written in the form 'table_name.column_name'
+  # can be used to qualify the table name of a particular condition. For instance:
+  #
+  #   Student.joins(:schools).where(schools: { category: 'public' })
+  #   Student.joins(:schools).where('schools.category' => 'public' )
+  #
+  # == Overwriting default accessors
+  #
+  # All column values are automatically available through basic accessors on the Active Record
+  # object, but sometimes you want to specialize this behavior. This can be done by overwriting
+  # the default accessors (using the same name as the attribute) and calling
+  # <tt>read_attribute(attr_name)</tt> and <tt>write_attribute(attr_name, value)</tt> to actually
+  # change things.
+  #
+  #   class Song < ActiveRecord::Base
+  #     # Uses an integer of seconds to hold the length of the song
+  #
+  #     def length=(minutes)
+  #       write_attribute(:length, minutes.to_i * 60)
+  #     end
+  #
+  #     def length
+  #       read_attribute(:length) / 60
+  #     end
+  #   end
+  #
+  # You can alternatively use <tt>self[:attribute]=(value)</tt> and <tt>self[:attribute]</tt>
+  # instead of <tt>write_attribute(:attribute, value)</tt> and <tt>read_attribute(:attribute)</tt>.
+  #
+  # == Attribute query methods
+  #
+  # In addition to the basic accessors, query methods are also automatically available on the Active Record object.
+  # Query methods allow you to test whether an attribute value is present.
+  # For numeric values, present is defined as non-zero.
+  #
+  # For example, an Active Record User with the <tt>name</tt> attribute has a <tt>name?</tt> method that you can call
+  # to determine whether the user has a name:
+  #
+  #   user = User.new(name: "David")
+  #   user.name? # => true
+  #
+  #   anonymous = User.new(name: "")
+  #   anonymous.name? # => false
+  #
+  # == Accessing attributes before they have been typecasted
+  #
+  # Sometimes you want to be able to read the raw attribute data without having the column-determined
+  # typecast run its course first. That can be done by using the <tt><attribute>_before_type_cast</tt>
+  # accessors that all attributes have. For example, if your Account model has a <tt>balance</tt> attribute,
+  # you can call <tt>account.balance_before_type_cast</tt> or <tt>account.id_before_type_cast</tt>.
+  #
+  # This is especially useful in validation situations where the user might supply a string for an
+  # integer field and you want to display the original string back in an error message. Accessing the
+  # attribute normally would typecast the string to 0, which isn't what you want.
+  #
+  # == Dynamic attribute-based finders
+  #
+  # Dynamic attribute-based finders are a mildly deprecated way of getting (and/or creating) objects
+  # by simple queries without turning to SQL. They work by appending the name of an attribute
+  # to <tt>find_by_</tt> like <tt>Person.find_by_user_name</tt>.
+  # Instead of writing <tt>Person.find_by(user_name: user_name)</tt>, you can use
+  # <tt>Person.find_by_user_name(user_name)</tt>.
+  #
+  # It's possible to add an exclamation point (!) on the end of the dynamic finders to get them to raise an
+  # <tt>ActiveRecord::RecordNotFound</tt> error if they do not return any records,
+  # like <tt>Person.find_by_last_name!</tt>.
+  #
+  # It's also possible to use multiple attributes in the same find by separating them with "_and_".
+  #
+  #  Person.find_by(user_name: user_name, password: password)
+  #  Person.find_by_user_name_and_password(user_name, password) # with dynamic finder
+  #
+  # It's even possible to call these dynamic finder methods on relations and named scopes.
+  #
+  #   Payment.order("created_on").find_by_amount(50)
+  #
+  # == Saving arrays, hashes, and other non-mappable objects in text columns
+  #
+  # Active Record can serialize any object in text columns using YAML. To do so, you must
+  # specify this with a call to the class method +serialize+.
+  # This makes it possible to store arrays, hashes, and other non-mappable objects without doing
+  # any additional work.
+  #
+  #   class User < ActiveRecord::Base
+  #     serialize :preferences
+  #   end
+  #
+  #   user = User.create(preferences: { "background" => "black", "display" => large })
+  #   User.find(user.id).preferences # => { "background" => "black", "display" => large }
+  #
+  # You can also specify a class option as the second parameter that'll raise an exception
+  # if a serialized object is retrieved as a descendant of a class not in the hierarchy.
+  #
+  #   class User < ActiveRecord::Base
+  #     serialize :preferences, Hash
+  #   end
+  #
+  #   user = User.create(preferences: %w( one two three ))
+  #   User.find(user.id).preferences    # raises SerializationTypeMismatch
+  #
+  # When you specify a class option, the default value for that attribute will be a new
+  # instance of that class.
+  #
+  #   class User < ActiveRecord::Base
+  #     serialize :preferences, OpenStruct
+  #   end
+  #
+  #   user = User.new
+  #   user.preferences.theme_color = "red"
+  #
+  #
+  # == Single table inheritance
+  #
+  # Active Record allows inheritance by storing the name of the class in a
+  # column that is named "type" by default. See ActiveRecord::Inheritance for
+  # more details.
+  #
+  # == Connection to multiple databases in different models
+  #
+  # Connections are usually created through ActiveRecord::Base.establish_connection and retrieved
+  # by ActiveRecord::Base.connection. All classes inheriting from ActiveRecord::Base will use this
+  # connection. But you can also set a class-specific connection. For example, if Course is an
+  # ActiveRecord::Base, but resides in a different database, you can just say <tt>Course.establish_connection</tt>
+  # and Course and all of its subclasses will use this connection instead.
+  #
+  # This feature is implemented by keeping a connection pool in ActiveRecord::Base that is
+  # a Hash indexed by the class. If a connection is requested, the retrieve_connection method
+  # will go up the class-hierarchy until a connection is found in the connection pool.
+  #
+  # == Exceptions
+  #
+  # * ActiveRecordError - Generic error class and superclass of all other errors raised by Active Record.
+  # * AdapterNotSpecified - The configuration hash used in <tt>establish_connection</tt> didn't include an
+  #   <tt>:adapter</tt> key.
+  # * AdapterNotFound - The <tt>:adapter</tt> key used in <tt>establish_connection</tt> specified a
+  #   non-existent adapter
+  #   (or a bad spelling of an existing one).
+  # * AssociationTypeMismatch - The object assigned to the association wasn't of the type
+  #   specified in the association definition.
+  # * AttributeAssignmentError - An error occurred while doing a mass assignment through the
+  #   <tt>attributes=</tt> method.
+  #   You can inspect the +attribute+ property of the exception object to determine which attribute
+  #   triggered the error.
+  # * ConnectionNotEstablished - No connection has been established. Use <tt>establish_connection</tt>
+  #   before querying.
+  # * MultiparameterAssignmentErrors - Collection of errors that occurred during a mass assignment using the
+  #   <tt>attributes=</tt> method. The +errors+ property of this exception contains an array of
+  #   AttributeAssignmentError
+  #   objects that should be inspected to determine which attributes triggered the errors.
+  # * RecordInvalid - raised by save! and create! when the record is invalid.
+  # * RecordNotFound - No record responded to the +find+ method. Either the row with the given ID doesn't exist
+  #   or the row didn't meet the additional restrictions. Some +find+ calls do not raise this exception to signal
+  #   nothing was found, please check its documentation for further details.
+  # * SerializationTypeMismatch - The serialized object wasn't of the class specified as the second parameter.
+  # * StatementInvalid - The database server rejected the SQL statement. The precise error is added in the message.
+  #
+  # *Note*: The attributes listed are class-level attributes (accessible from both the class and instance level).
+  # So it's possible to assign a logger to the class through <tt>Base.logger=</tt> which will then be used by all
+  # instances in the current object space.
+  class Base
+    extend ActiveModel::Naming
+
+    extend ActiveSupport::Benchmarkable
+    extend ActiveSupport::DescendantsTracker
+
+    extend ConnectionHandling
+    extend QueryCache::ClassMethods
+    extend Querying
+    extend Translation
+    extend DynamicMatchers
+    extend Explain
+    extend Enum
+    extend Delegation::DelegateCache
+
+    include Core
+    include Persistence
+    include ReadonlyAttributes
+    include ModelSchema
+    include Inheritance
+    include Scoping
+    include Sanitization
+    include AttributeAssignment
+    include ActiveModel::Conversion
+    include Integration
+    include Validations
+    include CounterCache
+    include Attributes
+    include AttributeDecorators
+    include Locking::Optimistic
+    include Locking::Pessimistic
+    include AttributeMethods
+    include Callbacks
+    include Timestamp
+    include Associations
+    include ActiveModel::SecurePassword
+    include AutosaveAssociation
+    include NestedAttributes
+    include Aggregations
+    include Transactions
+    include NoTouching
+    include Reflection
+    include Serialization
+    include Store
+  end
+
+  ActiveSupport.run_load_hooks(:active_record, Base)
+end
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
new file mode 100644
index 0000000000..5955673b42
--- /dev/null
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -0,0 +1,313 @@
+module ActiveRecord
+  # = Active Record Callbacks
+  #
+  # Callbacks are hooks into the life cycle of an Active Record object that allow you to trigger logic
+  # before or after an alteration of the object state. This can be used to make sure that associated and
+  # dependent objects are deleted when +destroy+ is called (by overwriting +before_destroy+) or to massage attributes
+  # before they're validated (by overwriting +before_validation+). As an example of the callbacks initiated, consider
+  # the <tt>Base#save</tt> call for a new record:
+  #
+  # * (-) <tt>save</tt>
+  # * (-) <tt>valid</tt>
+  # * (1) <tt>before_validation</tt>
+  # * (-) <tt>validate</tt>
+  # * (2) <tt>after_validation</tt>
+  # * (3) <tt>before_save</tt>
+  # * (4) <tt>before_create</tt>
+  # * (-) <tt>create</tt>
+  # * (5) <tt>after_create</tt>
+  # * (6) <tt>after_save</tt>
+  # * (7) <tt>after_commit</tt>
+  #
+  # Also, an <tt>after_rollback</tt> callback can be configured to be triggered whenever a rollback is issued.
+  # Check out <tt>ActiveRecord::Transactions</tt> for more details about <tt>after_commit</tt> and
+  # <tt>after_rollback</tt>.
+  #
+  # Additionally, an <tt>after_touch</tt> callback is triggered whenever an
+  # object is touched.
+  #
+  # Lastly an <tt>after_find</tt> and <tt>after_initialize</tt> callback is triggered for each object that
+  # is found and instantiated by a finder, with <tt>after_initialize</tt> being triggered after new objects
+  # are instantiated as well.
+  #
+  # There are nineteen callbacks in total, which give you immense power to react and prepare for each state in the
+  # Active Record life cycle. The sequence for calling <tt>Base#save</tt> for an existing record is similar,
+  # except that each <tt>_create</tt> callback is replaced by the corresponding <tt>_update</tt> callback.
+  #
+  # Examples:
+  #   class CreditCard < ActiveRecord::Base
+  #     # Strip everything but digits, so the user can specify "555 234 34" or
+  #     # "5552-3434" and both will mean "55523434"
+  #     before_validation(on: :create) do
+  #       self.number = number.gsub(/[^0-9]/, "") if attribute_present?("number")
+  #     end
+  #   end
+  #
+  #   class Subscription < ActiveRecord::Base
+  #     before_create :record_signup
+  #
+  #     private
+  #       def record_signup
+  #         self.signed_up_on = Date.today
+  #       end
+  #   end
+  #
+  #   class Firm < ActiveRecord::Base
+  #     # Destroys the associated clients and people when the firm is destroyed
+  #     before_destroy { |record| Person.destroy_all "firm_id = #{record.id}"   }
+  #     before_destroy { |record| Client.destroy_all "client_of = #{record.id}" }
+  #   end
+  #
+  # == Inheritable callback queues
+  #
+  # Besides the overwritable callback methods, it's also possible to register callbacks through the
+  # use of the callback macros. Their main advantage is that the macros add behavior into a callback
+  # queue that is kept intact down through an inheritance hierarchy.
+  #
+  #   class Topic < ActiveRecord::Base
+  #     before_destroy :destroy_author
+  #   end
+  #
+  #   class Reply < Topic
+  #     before_destroy :destroy_readers
+  #   end
+  #
+  # Now, when <tt>Topic#destroy</tt> is run only +destroy_author+ is called. When <tt>Reply#destroy</tt> is
+  # run, both +destroy_author+ and +destroy_readers+ are called. Contrast this to the following situation
+  # where the +before_destroy+ method is overridden:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     def before_destroy() destroy_author end
+  #   end
+  #
+  #   class Reply < Topic
+  #     def before_destroy() destroy_readers end
+  #   end
+  #
+  # In that case, <tt>Reply#destroy</tt> would only run +destroy_readers+ and _not_ +destroy_author+.
+  # So, use the callback macros when you want to ensure that a certain callback is called for the entire
+  # hierarchy, and use the regular overwritable methods when you want to leave it up to each descendant
+  # to decide whether they want to call +super+ and trigger the inherited callbacks.
+  #
+  # *IMPORTANT:* In order for inheritance to work for the callback queues, you must specify the
+  # callbacks before specifying the associations. Otherwise, you might trigger the loading of a
+  # child before the parent has registered the callbacks and they won't be inherited.
+  #
+  # == Types of callbacks
+  #
+  # There are four types of callbacks accepted by the callback macros: Method references (symbol), callback objects,
+  # inline methods (using a proc), and inline eval methods (using a string). Method references and callback objects
+  # are the recommended approaches, inline methods using a proc are sometimes appropriate (such as for
+  # creating mix-ins), and inline eval methods are deprecated.
+  #
+  # The method reference callbacks work by specifying a protected or private method available in the object, like this:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     before_destroy :delete_parents
+  #
+  #     private
+  #       def delete_parents
+  #         self.class.delete_all "parent_id = #{id}"
+  #       end
+  #   end
+  #
+  # The callback objects have methods named after the callback called with the record as the only parameter, such as:
+  #
+  #   class BankAccount < ActiveRecord::Base
+  #     before_save      EncryptionWrapper.new
+  #     after_save       EncryptionWrapper.new
+  #     after_initialize EncryptionWrapper.new
+  #   end
+  #
+  #   class EncryptionWrapper
+  #     def before_save(record)
+  #       record.credit_card_number = encrypt(record.credit_card_number)
+  #     end
+  #
+  #     def after_save(record)
+  #       record.credit_card_number = decrypt(record.credit_card_number)
+  #     end
+  #
+  #     alias_method :after_initialize, :after_save
+  #
+  #     private
+  #       def encrypt(value)
+  #         # Secrecy is committed
+  #       end
+  #
+  #       def decrypt(value)
+  #         # Secrecy is unveiled
+  #       end
+  #   end
+  #
+  # So you specify the object you want messaged on a given callback. When that callback is triggered, the object has
+  # a method by the name of the callback messaged. You can make these callbacks more flexible by passing in other
+  # initialization data such as the name of the attribute to work with:
+  #
+  #   class BankAccount < ActiveRecord::Base
+  #     before_save      EncryptionWrapper.new("credit_card_number")
+  #     after_save       EncryptionWrapper.new("credit_card_number")
+  #     after_initialize EncryptionWrapper.new("credit_card_number")
+  #   end
+  #
+  #   class EncryptionWrapper
+  #     def initialize(attribute)
+  #       @attribute = attribute
+  #     end
+  #
+  #     def before_save(record)
+  #       record.send("#{@attribute}=", encrypt(record.send("#{@attribute}")))
+  #     end
+  #
+  #     def after_save(record)
+  #       record.send("#{@attribute}=", decrypt(record.send("#{@attribute}")))
+  #     end
+  #
+  #     alias_method :after_initialize, :after_save
+  #
+  #     private
+  #       def encrypt(value)
+  #         # Secrecy is committed
+  #       end
+  #
+  #       def decrypt(value)
+  #         # Secrecy is unveiled
+  #       end
+  #   end
+  #
+  # The callback macros usually accept a symbol for the method they're supposed to run, but you can also
+  # pass a "method string", which will then be evaluated within the binding of the callback. Example:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     before_destroy 'self.class.delete_all "parent_id = #{id}"'
+  #   end
+  #
+  # Notice that single quotes (') are used so the <tt>#{id}</tt> part isn't evaluated until the callback
+  # is triggered. Also note that these inline callbacks can be stacked just like the regular ones:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     before_destroy 'self.class.delete_all "parent_id = #{id}"',
+  #                    'puts "Evaluated after parents are destroyed"'
+  #   end
+  #
+  # == <tt>before_validation*</tt> returning statements
+  #
+  # If the returning value of a +before_validation+ callback can be evaluated to +false+, the process will be
+  # aborted and <tt>Base#save</tt> will return +false+. If Base#save! is called it will raise a
+  # ActiveRecord::RecordInvalid exception. Nothing will be appended to the errors object.
+  #
+  # == Canceling callbacks
+  #
+  # If a <tt>before_*</tt> callback returns +false+, all the later callbacks and the associated action are
+  # cancelled. If an <tt>after_*</tt> callback returns +false+, all the later callbacks are cancelled.
+  # Callbacks are generally run in the order they are defined, with the exception of callbacks defined as
+  # methods on the model, which are called last.
+  #
+  # == Ordering callbacks
+  #
+  # Sometimes the code needs that the callbacks execute in a specific order. For example, a +before_destroy+
+  # callback (+log_children+ in this case) should be executed before the children get destroyed by the +dependent: destroy+ option.
+  #
+  # Let's look at the code below:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     has_many :children, dependent: destroy
+  #
+  #     before_destroy :log_children
+  #
+  #     private
+  #       def log_children
+  #         # Child processing
+  #       end
+  #   end
+  #
+  # In this case, the problem is that when the +before_destroy+ callback is executed, the children are not available
+  # because the +destroy+ callback gets executed first. You can use the +prepend+ option on the +before_destroy+ callback to avoid this.
+  #
+  #   class Topic < ActiveRecord::Base
+  #     has_many :children, dependent: destroy
+  #
+  #     before_destroy :log_children, prepend: true
+  #
+  #     private
+  #       def log_children
+  #         # Child processing
+  #       end
+  #   end
+  #
+  # This way, the +before_destroy+ gets executed before the <tt>dependent: destroy</tt> is called, and the data is still available.
+  #
+  # == Transactions
+  #
+  # The entire callback chain of a +save+, <tt>save!</tt>, or +destroy+ call runs
+  # within a transaction. That includes <tt>after_*</tt> hooks. If everything
+  # goes fine a COMMIT is executed once the chain has been completed.
+  #
+  # If a <tt>before_*</tt> callback cancels the action a ROLLBACK is issued. You
+  # can also trigger a ROLLBACK raising an exception in any of the callbacks,
+  # including <tt>after_*</tt> hooks. Note, however, that in that case the client
+  # needs to be aware of it because an ordinary +save+ will raise such exception
+  # instead of quietly returning +false+.
+  #
+  # == Debugging callbacks
+  #
+  # The callback chain is accessible via the <tt>_*_callbacks</tt> method on an object. ActiveModel Callbacks support
+  # <tt>:before</tt>, <tt>:after</tt> and <tt>:around</tt> as values for the <tt>kind</tt> property. The <tt>kind</tt> property
+  # defines what part of the chain the callback runs in.
+  #
+  # To find all callbacks in the before_save callback chain:
+  #
+  #   Topic._save_callbacks.select { |cb| cb.kind.eql?(:before) }
+  #
+  # Returns an array of callback objects that form the before_save chain.
+  #
+  # To further check if the before_save chain contains a proc defined as <tt>rest_when_dead</tt> use the <tt>filter</tt> property of the callback object:
+  #
+  #   Topic._save_callbacks.select { |cb| cb.kind.eql?(:before) }.collect(&:filter).include?(:rest_when_dead)
+  #
+  # Returns true or false depending on whether the proc is contained in the before_save callback chain on a Topic model.
+  #
+  module Callbacks
+    extend ActiveSupport::Concern
+
+    CALLBACKS = [
+      :after_initialize, :after_find, :after_touch, :before_validation, :after_validation,
+      :before_save, :around_save, :after_save, :before_create, :around_create,
+      :after_create, :before_update, :around_update, :after_update,
+      :before_destroy, :around_destroy, :after_destroy, :after_commit, :after_rollback
+    ]
+
+    module ClassMethods
+      include ActiveModel::Callbacks
+    end
+
+    included do
+      include ActiveModel::Validations::Callbacks
+
+      define_model_callbacks :initialize, :find, :touch, :only => :after
+      define_model_callbacks :save, :create, :update, :destroy
+    end
+
+    def destroy #:nodoc:
+      run_callbacks(:destroy) { super }
+    end
+
+    def touch(*) #:nodoc:
+      run_callbacks(:touch) { super }
+    end
+
+  private
+
+    def create_or_update #:nodoc:
+      run_callbacks(:save) { super }
+    end
+
+    def _create_record #:nodoc:
+      run_callbacks(:create) { super }
+    end
+
+    def _update_record(*) #:nodoc:
+      run_callbacks(:update) { super }
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/coders/json.rb b/activerecord/lib/active_record/coders/json.rb
new file mode 100644
index 0000000000..75d3bfe625
--- /dev/null
+++ b/activerecord/lib/active_record/coders/json.rb
@@ -0,0 +1,13 @@
+module ActiveRecord
+  module Coders # :nodoc:
+    class JSON # :nodoc:
+      def self.dump(obj)
+        ActiveSupport::JSON.encode(obj)
+      end
+
+      def self.load(json)
+        ActiveSupport::JSON.decode(json) unless json.nil?
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/coders/yaml_column.rb b/activerecord/lib/active_record/coders/yaml_column.rb
new file mode 100644
index 0000000000..d3d7396c91
--- /dev/null
+++ b/activerecord/lib/active_record/coders/yaml_column.rb
@@ -0,0 +1,38 @@
+require 'yaml'
+
+module ActiveRecord
+  module Coders # :nodoc:
+    class YAMLColumn # :nodoc:
+
+      attr_accessor :object_class
+
+      def initialize(object_class = Object)
+        @object_class = object_class
+      end
+
+      def dump(obj)
+        return if obj.nil?
+
+        unless obj.is_a?(object_class)
+          raise SerializationTypeMismatch,
+            "Attribute was supposed to be a #{object_class}, but was a #{obj.class}. -- #{obj.inspect}"
+        end
+        YAML.dump obj
+      end
+
+      def load(yaml)
+        return object_class.new if object_class != Object && yaml.nil?
+        return yaml unless yaml.is_a?(String) && yaml =~ /^---/
+        obj = YAML.load(yaml)
+
+        unless obj.is_a?(object_class) || obj.nil?
+          raise SerializationTypeMismatch,
+            "Attribute was supposed to be a #{object_class}, but was a #{obj.class}"
+        end
+        obj ||= object_class.new if object_class != Object
+
+        obj
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
new file mode 100644
index 0000000000..a5fa9d6adc
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -0,0 +1,657 @@
+require 'thread'
+require 'thread_safe'
+require 'monitor'
+require 'set'
+
+module ActiveRecord
+  # Raised when a connection could not be obtained within the connection
+  # acquisition timeout period: because max connections in pool
+  # are in use.
+  class ConnectionTimeoutError < ConnectionNotEstablished
+  end
+
+  module ConnectionAdapters
+    # Connection pool base class for managing Active Record database
+    # connections.
+    #
+    # == Introduction
+    #
+    # A connection pool synchronizes thread access to a limited number of
+    # database connections. The basic idea is that each thread checks out a
+    # database connection from the pool, uses that connection, and checks the
+    # connection back in. ConnectionPool is completely thread-safe, and will
+    # ensure that a connection cannot be used by two threads at the same time,
+    # as long as ConnectionPool's contract is correctly followed. It will also
+    # handle cases in which there are more threads than connections: if all
+    # connections have been checked out, and a thread tries to checkout a
+    # connection anyway, then ConnectionPool will wait until some other thread
+    # has checked in a connection.
+    #
+    # == Obtaining (checking out) a connection
+    #
+    # Connections can be obtained and used from a connection pool in several
+    # ways:
+    #
+    # 1. Simply use ActiveRecord::Base.connection as with Active Record 2.1 and
+    #    earlier (pre-connection-pooling). Eventually, when you're done with
+    #    the connection(s) and wish it to be returned to the pool, you call
+    #    ActiveRecord::Base.clear_active_connections!. This will be the
+    #    default behavior for Active Record when used in conjunction with
+    #    Action Pack's request handling cycle.
+    # 2. Manually check out a connection from the pool with
+    #    ActiveRecord::Base.connection_pool.checkout. You are responsible for
+    #    returning this connection to the pool when finished by calling
+    #    ActiveRecord::Base.connection_pool.checkin(connection).
+    # 3. Use ActiveRecord::Base.connection_pool.with_connection(&block), which
+    #    obtains a connection, yields it as the sole argument to the block,
+    #    and returns it to the pool after the block completes.
+    #
+    # Connections in the pool are actually AbstractAdapter objects (or objects
+    # compatible with AbstractAdapter's interface).
+    #
+    # == Options
+    #
+    # There are several connection-pooling-related options that you can add to
+    # your database connection configuration:
+    #
+    # * +pool+: number indicating size of connection pool (default 5)
+    # * +checkout_timeout+: number of seconds to block and wait for a connection
+    #   before giving up and raising a timeout error (default 5 seconds).
+    # * +reaping_frequency+: frequency in seconds to periodically run the
+    #   Reaper, which attempts to find and recover connections from dead
+    #   threads, which can occur if a programmer forgets to close a
+    #   connection at the end of a thread or a thread dies unexpectedly.
+    #   Regardless of this setting, the Reaper will be invoked before every
+    #   blocking wait. (Default nil, which means don't schedule the Reaper).
+    class ConnectionPool
+      # Threadsafe, fair, FIFO queue.  Meant to be used by ConnectionPool
+      # with which it shares a Monitor.  But could be a generic Queue.
+      #
+      # The Queue in stdlib's 'thread' could replace this class except
+      # stdlib's doesn't support waiting with a timeout.
+      class Queue
+        def initialize(lock = Monitor.new)
+          @lock = lock
+          @cond = @lock.new_cond
+          @num_waiting = 0
+          @queue = []
+        end
+
+        # Test if any threads are currently waiting on the queue.
+        def any_waiting?
+          synchronize do
+            @num_waiting > 0
+          end
+        end
+
+        # Returns the number of threads currently waiting on this
+        # queue.
+        def num_waiting
+          synchronize do
+            @num_waiting
+          end
+        end
+
+        # Add +element+ to the queue.  Never blocks.
+        def add(element)
+          synchronize do
+            @queue.push element
+            @cond.signal
+          end
+        end
+
+        # If +element+ is in the queue, remove and return it, or nil.
+        def delete(element)
+          synchronize do
+            @queue.delete(element)
+          end
+        end
+
+        # Remove all elements from the queue.
+        def clear
+          synchronize do
+            @queue.clear
+          end
+        end
+
+        # Remove the head of the queue.
+        #
+        # If +timeout+ is not given, remove and return the head the
+        # queue if the number of available elements is strictly
+        # greater than the number of threads currently waiting (that
+        # is, don't jump ahead in line).  Otherwise, return nil.
+        #
+        # If +timeout+ is given, block if it there is no element
+        # available, waiting up to +timeout+ seconds for an element to
+        # become available.
+        #
+        # Raises:
+        # - ConnectionTimeoutError if +timeout+ is given and no element
+        # becomes available after +timeout+ seconds,
+        def poll(timeout = nil)
+          synchronize do
+            if timeout
+              no_wait_poll || wait_poll(timeout)
+            else
+              no_wait_poll
+            end
+          end
+        end
+
+        private
+
+        def synchronize(&block)
+          @lock.synchronize(&block)
+        end
+
+        # Test if the queue currently contains any elements.
+        def any?
+          !@queue.empty?
+        end
+
+        # A thread can remove an element from the queue without
+        # waiting if an only if the number of currently available
+        # connections is strictly greater than the number of waiting
+        # threads.
+        def can_remove_no_wait?
+          @queue.size > @num_waiting
+        end
+
+        # Removes and returns the head of the queue if possible, or nil.
+        def remove
+          @queue.shift
+        end
+
+        # Remove and return the head the queue if the number of
+        # available elements is strictly greater than the number of
+        # threads currently waiting.  Otherwise, return nil.
+        def no_wait_poll
+          remove if can_remove_no_wait?
+        end
+
+        # Waits on the queue up to +timeout+ seconds, then removes and
+        # returns the head of the queue.
+        def wait_poll(timeout)
+          @num_waiting += 1
+
+          t0 = Time.now
+          elapsed = 0
+          loop do
+            @cond.wait(timeout - elapsed)
+
+            return remove if any?
+
+            elapsed = Time.now - t0
+            if elapsed >= timeout
+              msg = 'could not obtain a database connection within %0.3f seconds (waited %0.3f seconds)' %
+                [timeout, elapsed]
+              raise ConnectionTimeoutError, msg
+            end
+          end
+        ensure
+          @num_waiting -= 1
+        end
+      end
+
+      # Every +frequency+ seconds, the reaper will call +reap+ on +pool+.
+      # A reaper instantiated with a nil frequency will never reap the
+      # connection pool.
+      #
+      # Configure the frequency by setting "reaping_frequency" in your
+      # database yaml file.
+      class Reaper
+        attr_reader :pool, :frequency
+
+        def initialize(pool, frequency)
+          @pool      = pool
+          @frequency = frequency
+        end
+
+        def run
+          return unless frequency
+          Thread.new(frequency, pool) { |t, p|
+            while true
+              sleep t
+              p.reap
+            end
+          }
+        end
+      end
+
+      include MonitorMixin
+
+      attr_accessor :automatic_reconnect, :checkout_timeout
+      attr_reader :spec, :connections, :size, :reaper
+
+      # Creates a new ConnectionPool object. +spec+ is a ConnectionSpecification
+      # object which describes database connection information (e.g. adapter,
+      # host name, username, password, etc), as well as the maximum size for
+      # this ConnectionPool.
+      #
+      # The default ConnectionPool maximum size is 5.
+      def initialize(spec)
+        super()
+
+        @spec = spec
+
+        @checkout_timeout = spec.config[:checkout_timeout] || 5
+        @reaper  = Reaper.new self, spec.config[:reaping_frequency]
+        @reaper.run
+
+        # default max pool size to 5
+        @size = (spec.config[:pool] && spec.config[:pool].to_i) || 5
+
+        # The cache of reserved connections mapped to threads
+        @reserved_connections = ThreadSafe::Cache.new(:initial_capacity => @size)
+
+        @connections         = []
+        @automatic_reconnect = true
+
+        @available = Queue.new self
+      end
+
+      # Retrieve the connection associated with the current thread, or call
+      # #checkout to obtain one if necessary.
+      #
+      # #connection can be called any number of times; the connection is
+      # held in a hash keyed by the thread id.
+      def connection
+        # this is correctly done double-checked locking
+        # (ThreadSafe::Cache's lookups have volatile semantics)
+        @reserved_connections[current_connection_id] || synchronize do
+          @reserved_connections[current_connection_id] ||= checkout
+        end
+      end
+
+      # Is there an open connection that is being used for the current thread?
+      def active_connection?
+        synchronize do
+          @reserved_connections.fetch(current_connection_id) {
+            return false
+          }.in_use?
+        end
+      end
+
+      # Signal that the thread is finished with the current connection.
+      # #release_connection releases the connection-thread association
+      # and returns the connection to the pool.
+      def release_connection(with_id = current_connection_id)
+        synchronize do
+          conn = @reserved_connections.delete(with_id)
+          checkin conn if conn
+        end
+      end
+
+      # If a connection already exists yield it to the block. If no connection
+      # exists checkout a connection, yield it to the block, and checkin the
+      # connection when finished.
+      def with_connection
+        connection_id = current_connection_id
+        fresh_connection = true unless active_connection?
+        yield connection
+      ensure
+        release_connection(connection_id) if fresh_connection
+      end
+
+      # Returns true if a connection has already been opened.
+      def connected?
+        synchronize { @connections.any? }
+      end
+
+      # Disconnects all connections in the pool, and clears the pool.
+      def disconnect!
+        synchronize do
+          @reserved_connections.clear
+          @connections.each do |conn|
+            checkin conn
+            conn.disconnect!
+          end
+          @connections = []
+          @available.clear
+        end
+      end
+
+      # Clears the cache which maps classes.
+      def clear_reloadable_connections!
+        synchronize do
+          @reserved_connections.clear
+          @connections.each do |conn|
+            checkin conn
+            conn.disconnect! if conn.requires_reloading?
+          end
+          @connections.delete_if do |conn|
+            conn.requires_reloading?
+          end
+          @available.clear
+          @connections.each do |conn|
+            @available.add conn
+          end
+        end
+      end
+
+      # Check-out a database connection from the pool, indicating that you want
+      # to use it. You should call #checkin when you no longer need this.
+      #
+      # This is done by either returning and leasing existing connection, or by
+      # creating a new connection and leasing it.
+      #
+      # If all connections are leased and the pool is at capacity (meaning the
+      # number of currently leased connections is greater than or equal to the
+      # size limit set), an ActiveRecord::ConnectionTimeoutError exception will be raised.
+      #
+      # Returns: an AbstractAdapter object.
+      #
+      # Raises:
+      # - ConnectionTimeoutError: no connection can be obtained from the pool.
+      def checkout
+        synchronize do
+          conn = acquire_connection
+          conn.lease
+          checkout_and_verify(conn)
+        end
+      end
+
+      # Check-in a database connection back into the pool, indicating that you
+      # no longer need this connection.
+      #
+      # +conn+: an AbstractAdapter object, which was obtained by earlier by
+      # calling +checkout+ on this pool.
+      def checkin(conn)
+        synchronize do
+          owner = conn.owner
+
+          conn.run_callbacks :checkin do
+            conn.expire
+          end
+
+          release owner
+
+          @available.add conn
+        end
+      end
+
+      # Remove a connection from the connection pool.  The connection will
+      # remain open and active but will no longer be managed by this pool.
+      def remove(conn)
+        synchronize do
+          @connections.delete conn
+          @available.delete conn
+
+          release conn.owner
+
+          @available.add checkout_new_connection if @available.any_waiting?
+        end
+      end
+
+      # Recover lost connections for the pool.  A lost connection can occur if
+      # a programmer forgets to checkin a connection at the end of a thread
+      # or a thread dies unexpectedly.
+      def reap
+        stale_connections = synchronize do
+          @connections.select do |conn|
+            conn.in_use? && !conn.owner.alive?
+          end
+        end
+
+        stale_connections.each do |conn|
+          synchronize do
+            if conn.active?
+              conn.reset!
+              checkin conn
+            else
+              remove conn
+            end
+          end
+        end
+      end
+
+      private
+
+      # Acquire a connection by one of 1) immediately removing one
+      # from the queue of available connections, 2) creating a new
+      # connection if the pool is not at capacity, 3) waiting on the
+      # queue for a connection to become available.
+      #
+      # Raises:
+      # - ConnectionTimeoutError if a connection could not be acquired
+      def acquire_connection
+        if conn = @available.poll
+          conn
+        elsif @connections.size < @size
+          checkout_new_connection
+        else
+          reap
+          @available.poll(@checkout_timeout)
+        end
+      end
+
+      def release(owner)
+        thread_id = owner.object_id
+
+        @reserved_connections.delete thread_id
+      end
+
+      def new_connection
+        Base.send(spec.adapter_method, spec.config)
+      end
+
+      def current_connection_id #:nodoc:
+        Base.connection_id ||= Thread.current.object_id
+      end
+
+      def checkout_new_connection
+        raise ConnectionNotEstablished unless @automatic_reconnect
+
+        c = new_connection
+        c.pool = self
+        @connections << c
+        c
+      end
+
+      def checkout_and_verify(c)
+        c.run_callbacks :checkout do
+          c.verify!
+        end
+        c
+      end
+    end
+
+    # ConnectionHandler is a collection of ConnectionPool objects. It is used
+    # for keeping separate connection pools for Active Record models that connect
+    # to different databases.
+    #
+    # For example, suppose that you have 5 models, with the following hierarchy:
+    #
+    #   class Author < ActiveRecord::Base
+    #   end
+    #
+    #   class BankAccount < ActiveRecord::Base
+    #   end
+    #
+    #   class Book < ActiveRecord::Base
+    #     establish_connection "library_db"
+    #   end
+    #
+    #   class ScaryBook < Book
+    #   end
+    #
+    #   class GoodBook < Book
+    #   end
+    #
+    # And a database.yml that looked like this:
+    #
+    #   development:
+    #     database: my_application
+    #     host: localhost
+    #
+    #   library_db:
+    #     database: library
+    #     host: some.library.org
+    #
+    # Your primary database in the development environment is "my_application"
+    # but the Book model connects to a separate database called "library_db"
+    # (this can even be a database on a different machine).
+    #
+    # Book, ScaryBook and GoodBook will all use the same connection pool to
+    # "library_db" while Author, BankAccount, and any other models you create
+    # will use the default connection pool to "my_application".
+    #
+    # The various connection pools are managed by a single instance of
+    # ConnectionHandler accessible via ActiveRecord::Base.connection_handler.
+    # All Active Record models use this handler to determine the connection pool that they
+    # should use.
+    class ConnectionHandler
+      def initialize
+        # These caches are keyed by klass.name, NOT klass. Keying them by klass
+        # alone would lead to memory leaks in development mode as all previous
+        # instances of the class would stay in memory.
+        @owner_to_pool = ThreadSafe::Cache.new(:initial_capacity => 2) do |h,k|
+          h[k] = ThreadSafe::Cache.new(:initial_capacity => 2)
+        end
+        @class_to_pool = ThreadSafe::Cache.new(:initial_capacity => 2) do |h,k|
+          h[k] = ThreadSafe::Cache.new
+        end
+      end
+
+      def connection_pool_list
+        owner_to_pool.values.compact
+      end
+
+      def connection_pools
+        ActiveSupport::Deprecation.warn(
+          "In the next release, this will return the same as #connection_pool_list. " \
+          "(An array of pools, rather than a hash mapping specs to pools.)"
+        )
+        Hash[connection_pool_list.map { |pool| [pool.spec, pool] }]
+      end
+
+      def establish_connection(owner, spec)
+        @class_to_pool.clear
+        raise RuntimeError, "Anonymous class is not allowed." unless owner.name
+        owner_to_pool[owner.name] = ConnectionAdapters::ConnectionPool.new(spec)
+      end
+
+      # Returns true if there are any active connections among the connection
+      # pools that the ConnectionHandler is managing.
+      def active_connections?
+        connection_pool_list.any?(&:active_connection?)
+      end
+
+      # Returns any connections in use by the current thread back to the pool,
+      # and also returns connections to the pool cached by threads that are no
+      # longer alive.
+      def clear_active_connections!
+        connection_pool_list.each(&:release_connection)
+      end
+
+      # Clears the cache which maps classes.
+      def clear_reloadable_connections!
+        connection_pool_list.each(&:clear_reloadable_connections!)
+      end
+
+      def clear_all_connections!
+        connection_pool_list.each(&:disconnect!)
+      end
+
+      # Locate the connection of the nearest super class. This can be an
+      # active or defined connection: if it is the latter, it will be
+      # opened and set as the active connection for the class it was defined
+      # for (not necessarily the current class).
+      def retrieve_connection(klass) #:nodoc:
+        pool = retrieve_connection_pool(klass)
+        raise ConnectionNotEstablished, "No connection pool for #{klass}" unless pool
+        conn = pool.connection
+        raise ConnectionNotEstablished, "No connection for #{klass} in connection pool" unless conn
+        conn
+      end
+
+      # Returns true if a connection that's accessible to this class has
+      # already been opened.
+      def connected?(klass)
+        conn = retrieve_connection_pool(klass)
+        conn && conn.connected?
+      end
+
+      # Remove the connection for this class. This will close the active
+      # connection and the defined connection (if they exist). The result
+      # can be used as an argument for establish_connection, for easily
+      # re-establishing the connection.
+      def remove_connection(owner)
+        if pool = owner_to_pool.delete(owner.name)
+          @class_to_pool.clear
+          pool.automatic_reconnect = false
+          pool.disconnect!
+          pool.spec.config
+        end
+      end
+
+      # Retrieving the connection pool happens a lot so we cache it in @class_to_pool.
+      # This makes retrieving the connection pool O(1) once the process is warm.
+      # When a connection is established or removed, we invalidate the cache.
+      #
+      # Ideally we would use #fetch here, as class_to_pool[klass] may sometimes be nil.
+      # However, benchmarking (https://gist.github.com/jonleighton/3552829) showed that
+      # #fetch is significantly slower than #[]. So in the nil case, no caching will
+      # take place, but that's ok since the nil case is not the common one that we wish
+      # to optimise for.
+      def retrieve_connection_pool(klass)
+        class_to_pool[klass.name] ||= begin
+          until pool = pool_for(klass)
+            klass = klass.superclass
+            break unless klass <= Base
+          end
+
+          class_to_pool[klass.name] = pool
+        end
+      end
+
+      private
+
+      def owner_to_pool
+        @owner_to_pool[Process.pid]
+      end
+
+      def class_to_pool
+        @class_to_pool[Process.pid]
+      end
+
+      def pool_for(owner)
+        owner_to_pool.fetch(owner.name) {
+          if ancestor_pool = pool_from_any_process_for(owner)
+            # A connection was established in an ancestor process that must have
+            # subsequently forked. We can't reuse the connection, but we can copy
+            # the specification and establish a new connection with it.
+            establish_connection owner, ancestor_pool.spec
+          else
+            owner_to_pool[owner.name] = nil
+          end
+        }
+      end
+
+      def pool_from_any_process_for(owner)
+        owner_to_pool = @owner_to_pool.values.find { |v| v[owner.name] }
+        owner_to_pool && owner_to_pool[owner.name]
+      end
+    end
+
+    class ConnectionManagement
+      def initialize(app)
+        @app = app
+      end
+
+      def call(env)
+        testing = env.key?('rack.test')
+
+        response = @app.call(env)
+        response[2] = ::Rack::BodyProxy.new(response[2]) do
+          ActiveRecord::Base.clear_active_connections! unless testing
+        end
+
+        response
+      rescue Exception
+        ActiveRecord::Base.clear_active_connections! unless testing
+        raise
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_limits.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_limits.rb
new file mode 100644
index 0000000000..c0a2111571
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_limits.rb
@@ -0,0 +1,67 @@
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module DatabaseLimits
+
+      # Returns the maximum length of a table alias.
+      def table_alias_length
+        255
+      end
+
+      # Returns the maximum length of a column name.
+      def column_name_length
+        64
+      end
+
+      # Returns the maximum length of a table name.
+      def table_name_length
+        64
+      end
+
+      # Returns the maximum allowed length for an index name. This
+      # limit is enforced by rails and Is less than or equal to
+      # <tt>index_name_length</tt>. The gap between
+      # <tt>index_name_length</tt> is to allow internal rails
+      # operations to use prefixes in temporary operations.
+      def allowed_index_name_length
+        index_name_length
+      end
+
+      # Returns the maximum length of an index name.
+      def index_name_length
+        64
+      end
+
+      # Returns the maximum number of columns per table.
+      def columns_per_table
+        1024
+      end
+
+      # Returns the maximum number of indexes per table.
+      def indexes_per_table
+        16
+      end
+
+      # Returns the maximum number of columns in a multicolumn index.
+      def columns_per_multicolumn_index
+        16
+      end
+
+      # Returns the maximum number of elements in an IN (x,y,z) clause.
+      # nil means no limit.
+      def in_clause_length
+        nil
+      end
+
+      # Returns the maximum length of an SQL query.
+      def sql_query_length
+        1048575
+      end
+
+      # Returns maximum number of joins in a single query.
+      def joins_per_query
+        256
+      end
+
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
new file mode 100644
index 0000000000..98e96099cb
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -0,0 +1,371 @@
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module DatabaseStatements
+      def initialize
+        super
+        reset_transaction
+      end
+
+      # Converts an arel AST to SQL
+      def to_sql(arel, binds = [])
+        if arel.respond_to?(:ast)
+          collected = visitor.accept(arel.ast, collector)
+          collected.compile(binds.dup, self)
+        else
+          arel
+        end
+      end
+
+      # This is used in the StatementCache object. It returns an object that
+      # can be used to query the database repeatedly.
+      def cacheable_query(arel) # :nodoc:
+        if prepared_statements
+          ActiveRecord::StatementCache.query visitor, arel.ast
+        else
+          ActiveRecord::StatementCache.partial_query visitor, arel.ast, collector
+        end
+      end
+
+      # Returns an ActiveRecord::Result instance.
+      def select_all(arel, name = nil, binds = [])
+        arel, binds = binds_from_relation arel, binds
+        select(to_sql(arel, binds), name, binds)
+      end
+
+      # Returns a record hash with the column names as keys and column values
+      # as values.
+      def select_one(arel, name = nil, binds = [])
+        select_all(arel, name, binds).first
+      end
+
+      # Returns a single value from a record
+      def select_value(arel, name = nil, binds = [])
+        if result = select_one(arel, name, binds)
+          result.values.first
+        end
+      end
+
+      # Returns an array of the values of the first column in a select:
+      #   select_values("SELECT id FROM companies LIMIT 3") => [1,2,3]
+      def select_values(arel, name = nil)
+        arel, binds = binds_from_relation arel, []
+        select_rows(to_sql(arel, binds), name, binds).map(&:first)
+      end
+
+      # Returns an array of arrays containing the field values.
+      # Order is the same as that returned by +columns+.
+      def select_rows(sql, name = nil, binds = [])
+      end
+      undef_method :select_rows
+
+      # Executes the SQL statement in the context of this connection.
+      def execute(sql, name = nil)
+      end
+      undef_method :execute
+
+      # Executes +sql+ statement in the context of this connection using
+      # +binds+ as the bind substitutes. +name+ is logged along with
+      # the executed +sql+ statement.
+      def exec_query(sql, name = 'SQL', binds = [])
+      end
+
+      # Executes insert +sql+ statement in the context of this connection using
+      # +binds+ as the bind substitutes. +name+ is logged along with
+      # the executed +sql+ statement.
+      def exec_insert(sql, name, binds, pk = nil, sequence_name = nil)
+        exec_query(sql, name, binds)
+      end
+
+      # Executes delete +sql+ statement in the context of this connection using
+      # +binds+ as the bind substitutes. +name+ is logged along with
+      # the executed +sql+ statement.
+      def exec_delete(sql, name, binds)
+        exec_query(sql, name, binds)
+      end
+
+      # Executes update +sql+ statement in the context of this connection using
+      # +binds+ as the bind substitutes. +name+ is logged along with
+      # the executed +sql+ statement.
+      def exec_update(sql, name, binds)
+        exec_query(sql, name, binds)
+      end
+
+      # Returns the last auto-generated ID from the affected table.
+      #
+      # +id_value+ will be returned unless the value is nil, in
+      # which case the database will attempt to calculate the last inserted
+      # id and return that value.
+      #
+      # If the next id was calculated in advance (as in Oracle), it should be
+      # passed in as +id_value+.
+      def insert(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [])
+        sql, binds = sql_for_insert(to_sql(arel, binds), pk, id_value, sequence_name, binds)
+        value      = exec_insert(sql, name, binds, pk, sequence_name)
+        id_value || last_inserted_id(value)
+      end
+
+      # Executes the update statement and returns the number of rows affected.
+      def update(arel, name = nil, binds = [])
+        exec_update(to_sql(arel, binds), name, binds)
+      end
+
+      # Executes the delete statement and returns the number of rows affected.
+      def delete(arel, name = nil, binds = [])
+        exec_delete(to_sql(arel, binds), name, binds)
+      end
+
+      # Returns +true+ when the connection adapter supports prepared statement
+      # caching, otherwise returns +false+
+      def supports_statement_cache?
+        false
+      end
+
+      # Runs the given block in a database transaction, and returns the result
+      # of the block.
+      #
+      # == Nested transactions support
+      #
+      # Most databases don't support true nested transactions. At the time of
+      # writing, the only database that supports true nested transactions that
+      # we're aware of, is MS-SQL.
+      #
+      # In order to get around this problem, #transaction will emulate the effect
+      # of nested transactions, by using savepoints:
+      # http://dev.mysql.com/doc/refman/5.0/en/savepoint.html
+      # Savepoints are supported by MySQL and PostgreSQL. SQLite3 version >= '3.6.8'
+      # supports savepoints.
+      #
+      # It is safe to call this method if a database transaction is already open,
+      # i.e. if #transaction is called within another #transaction block. In case
+      # of a nested call, #transaction will behave as follows:
+      #
+      # - The block will be run without doing anything. All database statements
+      #   that happen within the block are effectively appended to the already
+      #   open database transaction.
+      # - However, if +:requires_new+ is set, the block will be wrapped in a
+      #   database savepoint acting as a sub-transaction.
+      #
+      # === Caveats
+      #
+      # MySQL doesn't support DDL transactions. If you perform a DDL operation,
+      # then any created savepoints will be automatically released. For example,
+      # if you've created a savepoint, then you execute a CREATE TABLE statement,
+      # then the savepoint that was created will be automatically released.
+      #
+      # This means that, on MySQL, you shouldn't execute DDL operations inside
+      # a #transaction call that you know might create a savepoint. Otherwise,
+      # #transaction will raise exceptions when it tries to release the
+      # already-automatically-released savepoints:
+      #
+      #   Model.connection.transaction do  # BEGIN
+      #     Model.connection.transaction(requires_new: true) do  # CREATE SAVEPOINT active_record_1
+      #       Model.connection.create_table(...)
+      #       # active_record_1 now automatically released
+      #     end  # RELEASE SAVEPOINT active_record_1  <--- BOOM! database error!
+      #   end
+      #
+      # == Transaction isolation
+      #
+      # If your database supports setting the isolation level for a transaction, you can set
+      # it like so:
+      #
+      #   Post.transaction(isolation: :serializable) do
+      #     # ...
+      #   end
+      #
+      # Valid isolation levels are:
+      #
+      # * <tt>:read_uncommitted</tt>
+      # * <tt>:read_committed</tt>
+      # * <tt>:repeatable_read</tt>
+      # * <tt>:serializable</tt>
+      #
+      # You should consult the documentation for your database to understand the
+      # semantics of these different levels:
+      #
+      # * http://www.postgresql.org/docs/9.1/static/transaction-iso.html
+      # * https://dev.mysql.com/doc/refman/5.0/en/set-transaction.html
+      #
+      # An <tt>ActiveRecord::TransactionIsolationError</tt> will be raised if:
+      #
+      # * The adapter does not support setting the isolation level
+      # * You are joining an existing open transaction
+      # * You are creating a nested (savepoint) transaction
+      #
+      # The mysql, mysql2 and postgresql adapters support setting the transaction
+      # isolation level. However, support is disabled for MySQL versions below 5,
+      # because they are affected by a bug[http://bugs.mysql.com/bug.php?id=39170]
+      # which means the isolation level gets persisted outside the transaction.
+      def transaction(options = {})
+        options.assert_valid_keys :requires_new, :joinable, :isolation
+
+        if !options[:requires_new] && current_transaction.joinable?
+          if options[:isolation]
+            raise ActiveRecord::TransactionIsolationError, "cannot set isolation when joining a transaction"
+          end
+          yield
+        else
+          transaction_manager.within_new_transaction(options) { yield }
+        end
+      rescue ActiveRecord::Rollback
+        # rollbacks are silently swallowed
+      end
+
+      attr_reader :transaction_manager #:nodoc:
+
+      delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, to: :transaction_manager
+
+      def transaction_open?
+        current_transaction.open?
+      end
+
+      def reset_transaction #:nodoc:
+        @transaction_manager = TransactionManager.new(self)
+      end
+
+      # Register a record with the current transaction so that its after_commit and after_rollback callbacks
+      # can be called.
+      def add_transaction_record(record)
+        current_transaction.add_record(record)
+      end
+
+      # Begins the transaction (and turns off auto-committing).
+      def begin_db_transaction()    end
+
+      def transaction_isolation_levels
+        {
+          read_uncommitted: "READ UNCOMMITTED",
+          read_committed:   "READ COMMITTED",
+          repeatable_read:  "REPEATABLE READ",
+          serializable:     "SERIALIZABLE"
+        }
+      end
+
+      # Begins the transaction with the isolation level set. Raises an error by
+      # default; adapters that support setting the isolation level should implement
+      # this method.
+      def begin_isolated_db_transaction(isolation)
+        raise ActiveRecord::TransactionIsolationError, "adapter does not support setting transaction isolation"
+      end
+
+      # Commits the transaction (and turns on auto-committing).
+      def commit_db_transaction()   end
+
+      # Rolls back the transaction (and turns on auto-committing). Must be
+      # done if the transaction block raises an exception or returns false.
+      def rollback_db_transaction() end
+
+      def default_sequence_name(table, column)
+        nil
+      end
+
+      # Set the sequence to the max value of the table's column.
+      def reset_sequence!(table, column, sequence = nil)
+        # Do nothing by default. Implement for PostgreSQL, Oracle, ...
+      end
+
+      # Inserts the given fixture into the table. Overridden in adapters that require
+      # something beyond a simple insert (eg. Oracle).
+      def insert_fixture(fixture, table_name)
+        columns = schema_cache.columns_hash(table_name)
+
+        key_list   = []
+        value_list = fixture.map do |name, value|
+          key_list << quote_column_name(name)
+          quote(value, columns[name])
+        end
+
+        execute "INSERT INTO #{quote_table_name(table_name)} (#{key_list.join(', ')}) VALUES (#{value_list.join(', ')})", 'Fixture Insert'
+      end
+
+      def empty_insert_statement_value
+        "DEFAULT VALUES"
+      end
+
+      def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
+        "WHERE #{quoted_primary_key} IN (SELECT #{quoted_primary_key} FROM #{quoted_table_name} #{where_sql})"
+      end
+
+      # Sanitizes the given LIMIT parameter in order to prevent SQL injection.
+      #
+      # The +limit+ may be anything that can evaluate to a string via #to_s. It
+      # should look like an integer, or a comma-delimited list of integers, or
+      # an Arel SQL literal.
+      #
+      # Returns Integer and Arel::Nodes::SqlLiteral limits as is.
+      # Returns the sanitized limit parameter, either as an integer, or as a
+      # string which contains a comma-delimited list of integers.
+      def sanitize_limit(limit)
+        if limit.is_a?(Integer) || limit.is_a?(Arel::Nodes::SqlLiteral)
+          limit
+        elsif limit.to_s.include?(',')
+          Arel.sql limit.to_s.split(',').map{ |i| Integer(i) }.join(',')
+        else
+          Integer(limit)
+        end
+      end
+
+      # The default strategy for an UPDATE with joins is to use a subquery. This doesn't work
+      # on MySQL (even when aliasing the tables), but MySQL allows using JOIN directly in
+      # an UPDATE statement, so in the MySQL adapters we redefine this to do that.
+      def join_to_update(update, select) #:nodoc:
+        key = update.key
+        subselect = subquery_for(key, select)
+
+        update.where key.in(subselect)
+      end
+
+      def join_to_delete(delete, select, key) #:nodoc:
+        subselect = subquery_for(key, select)
+
+        delete.where key.in(subselect)
+      end
+
+      protected
+
+        # Returns a subquery for the given key using the join information.
+        def subquery_for(key, select)
+          subselect = select.clone
+          subselect.projections = [key]
+          subselect
+        end
+
+        # Returns an ActiveRecord::Result instance.
+        def select(sql, name = nil, binds = [])
+        end
+        undef_method :select
+
+        # Returns the last auto-generated ID from the affected table.
+        def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
+          execute(sql, name)
+          id_value
+        end
+
+        # Executes the update statement and returns the number of rows affected.
+        def update_sql(sql, name = nil)
+          execute(sql, name)
+        end
+
+        # Executes the delete statement and returns the number of rows affected.
+        def delete_sql(sql, name = nil)
+          update_sql(sql, name)
+        end
+
+        def sql_for_insert(sql, pk, id_value, sequence_name, binds)
+          [sql, binds]
+        end
+
+        def last_inserted_id(result)
+          row = result.rows.first
+          row && row.first
+        end
+
+        def binds_from_relation(relation, binds)
+          if relation.is_a?(Relation) && binds.empty?
+            relation, binds = relation.arel, relation.bind_values
+          end
+          [relation, binds]
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
new file mode 100644
index 0000000000..4a4506c7f5
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
@@ -0,0 +1,95 @@
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module QueryCache
+      class << self
+        def included(base) #:nodoc:
+          dirties_query_cache base, :insert, :update, :delete
+        end
+
+        def dirties_query_cache(base, *method_names)
+          method_names.each do |method_name|
+            base.class_eval <<-end_code, __FILE__, __LINE__ + 1
+              def #{method_name}(*)
+                clear_query_cache if @query_cache_enabled
+                super
+              end
+            end_code
+          end
+        end
+      end
+
+      attr_reader :query_cache, :query_cache_enabled
+
+      def initialize(*)
+        super
+        @query_cache         = Hash.new { |h,sql| h[sql] = {} }
+        @query_cache_enabled = false
+      end
+
+      # Enable the query cache within the block.
+      def cache
+        old, @query_cache_enabled = @query_cache_enabled, true
+        yield
+      ensure
+        @query_cache_enabled = old
+        clear_query_cache unless @query_cache_enabled
+      end
+
+      def enable_query_cache!
+        @query_cache_enabled = true
+      end
+
+      def disable_query_cache!
+        @query_cache_enabled = false
+      end
+
+      # Disable the query cache within the block.
+      def uncached
+        old, @query_cache_enabled = @query_cache_enabled, false
+        yield
+      ensure
+        @query_cache_enabled = old
+      end
+
+      # Clears the query cache.
+      #
+      # One reason you may wish to call this method explicitly is between queries
+      # that ask the database to randomize results. Otherwise the cache would see
+      # the same SQL query and repeatedly return the same result each time, silently
+      # undermining the randomness you were expecting.
+      def clear_query_cache
+        @query_cache.clear
+      end
+
+      def select_all(arel, name = nil, binds = [])
+        if @query_cache_enabled && !locked?(arel)
+          arel, binds = binds_from_relation arel, binds
+          sql = to_sql(arel, binds)
+          cache_sql(sql, binds) { super(sql, name, binds) }
+        else
+          super
+        end
+      end
+
+      private
+
+      def cache_sql(sql, binds)
+        result =
+          if @query_cache[sql].key?(binds)
+            ActiveSupport::Notifications.instrument("sql.active_record",
+              :sql => sql, :binds => binds, :name => "CACHE", :connection_id => object_id)
+            @query_cache[sql][binds]
+          else
+            @query_cache[sql][binds] = yield
+          end
+        result.dup
+      end
+
+      # If arel is locked this is a SELECT ... FOR UPDATE or somesuch. Such
+      # queries should not be cached.
+      def locked?(arel)
+        arel.respond_to?(:locked) && arel.locked
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
new file mode 100644
index 0000000000..eb88845913
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
@@ -0,0 +1,133 @@
+require 'active_support/core_ext/big_decimal/conversions'
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module Quoting
+      # Quotes the column value to help prevent
+      # {SQL injection attacks}[http://en.wikipedia.org/wiki/SQL_injection].
+      def quote(value, column = nil)
+        # records are quoted as their primary key
+        return value.quoted_id if value.respond_to?(:quoted_id)
+
+        if column
+          value = column.cast_type.type_cast_for_database(value)
+        end
+
+        _quote(value)
+      end
+
+      # Cast a +value+ to a type that the database understands. For example,
+      # SQLite does not understand dates, so this method will convert a Date
+      # to a String.
+      def type_cast(value, column)
+        if value.respond_to?(:quoted_id) && value.respond_to?(:id)
+          return value.id
+        end
+
+        if column
+          value = column.cast_type.type_cast_for_database(value)
+        end
+
+        _type_cast(value)
+      rescue TypeError
+        to_type = column ? " to #{column.type}" : ""
+        raise TypeError, "can't cast #{value.class}#{to_type}"
+      end
+
+      # Quotes a string, escaping any ' (single quote) and \ (backslash)
+      # characters.
+      def quote_string(s)
+        s.gsub(/\\/, '\&\&').gsub(/'/, "''") # ' (for ruby-mode)
+      end
+
+      # Quotes the column name. Defaults to no quoting.
+      def quote_column_name(column_name)
+        column_name
+      end
+
+      # Quotes the table name. Defaults to column name quoting.
+      def quote_table_name(table_name)
+        quote_column_name(table_name)
+      end
+
+      # Override to return the quoted table name for assignment. Defaults to
+      # table quoting.
+      #
+      # This works for mysql and mysql2 where table.column can be used to
+      # resolve ambiguity.
+      #
+      # We override this in the sqlite3 and postgresql adapters to use only
+      # the column name (as per syntax requirements).
+      def quote_table_name_for_assignment(table, attr)
+        quote_table_name("#{table}.#{attr}")
+      end
+
+      def quoted_true
+        "'t'"
+      end
+
+      def unquoted_true
+        't'
+      end
+
+      def quoted_false
+        "'f'"
+      end
+
+      def unquoted_false
+        'f'
+      end
+
+      def quoted_date(value)
+        if value.acts_like?(:time)
+          zone_conversion_method = ActiveRecord::Base.default_timezone == :utc ? :getutc : :getlocal
+
+          if value.respond_to?(zone_conversion_method)
+            value = value.send(zone_conversion_method)
+          end
+        end
+
+        value.to_s(:db)
+      end
+
+      private
+
+      def types_which_need_no_typecasting
+        [nil, Numeric, String]
+      end
+
+      def _quote(value)
+        case value
+        when String, ActiveSupport::Multibyte::Chars, Type::Binary::Data
+          "'#{quote_string(value.to_s)}'"
+        when true       then quoted_true
+        when false      then quoted_false
+        when nil        then "NULL"
+        # BigDecimals need to be put in a non-normalized form and quoted.
+        when BigDecimal then value.to_s('F')
+        when Numeric, ActiveSupport::Duration then value.to_s
+        when Date, Time then "'#{quoted_date(value)}'"
+        when Symbol     then "'#{quote_string(value.to_s)}'"
+        when Class      then "'#{value.to_s}'"
+        else
+          "'#{quote_string(YAML.dump(value))}'"
+        end
+      end
+
+      def _type_cast(value)
+        case value
+        when Symbol, ActiveSupport::Multibyte::Chars, Type::Binary::Data
+          value.to_s
+        when true       then unquoted_true
+        when false      then unquoted_false
+        # BigDecimals need to be put in a non-normalized form and quoted.
+        when BigDecimal then value.to_s('F')
+        when Date, Time then quoted_date(value)
+        when *types_which_need_no_typecasting
+          value
+        else raise TypeError
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/savepoints.rb b/activerecord/lib/active_record/connection_adapters/abstract/savepoints.rb
new file mode 100644
index 0000000000..25c17ce971
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/savepoints.rb
@@ -0,0 +1,21 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module Savepoints #:nodoc:
+      def supports_savepoints?
+        true
+      end
+
+      def create_savepoint(name = current_savepoint_name)
+        execute("SAVEPOINT #{name}")
+      end
+
+      def rollback_to_savepoint(name = current_savepoint_name)
+        execute("ROLLBACK TO SAVEPOINT #{name}")
+      end
+
+      def release_savepoint(name = current_savepoint_name)
+        execute("RELEASE SAVEPOINT #{name}")
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
new file mode 100644
index 0000000000..adad6cd542
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -0,0 +1,125 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class AbstractAdapter
+      class SchemaCreation # :nodoc:
+        def initialize(conn)
+          @conn = conn
+          @cache = {}
+        end
+
+        def accept(o)
+          m = @cache[o.class] ||= "visit_#{o.class.name.split('::').last}"
+          send m, o
+        end
+
+        def visit_AddColumn(o)
+          sql_type = type_to_sql(o.type, o.limit, o.precision, o.scale)
+          sql = "ADD #{quote_column_name(o.name)} #{sql_type}"
+          add_column_options!(sql, column_options(o))
+        end
+
+        private
+
+          def visit_AlterTable(o)
+            sql = "ALTER TABLE #{quote_table_name(o.name)} "
+            sql << o.adds.map { |col| visit_AddColumn col }.join(' ')
+            sql << o.foreign_key_adds.map { |fk| visit_AddForeignKey fk }.join(' ')
+            sql << o.foreign_key_drops.map { |fk| visit_DropForeignKey fk }.join(' ')
+          end
+
+          def visit_ColumnDefinition(o)
+            sql_type = type_to_sql(o.type, o.limit, o.precision, o.scale)
+            column_sql = "#{quote_column_name(o.name)} #{sql_type}"
+            add_column_options!(column_sql, column_options(o)) unless o.primary_key?
+            column_sql
+          end
+
+          def visit_TableDefinition(o)
+            create_sql = "CREATE#{' TEMPORARY' if o.temporary} TABLE "
+            create_sql << "#{quote_table_name(o.name)} "
+            create_sql << "(#{o.columns.map { |c| accept c }.join(', ')}) " unless o.as
+            create_sql << "#{o.options}"
+            create_sql << " AS #{@conn.to_sql(o.as)}" if o.as
+            create_sql
+          end
+
+          def visit_AddForeignKey(o)
+            sql = <<-SQL.strip_heredoc
+              ADD CONSTRAINT #{quote_column_name(o.name)}
+              FOREIGN KEY (#{quote_column_name(o.column)})
+                REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
+            SQL
+            sql << " #{action_sql('DELETE', o.on_delete)}" if o.on_delete
+            sql << " #{action_sql('UPDATE', o.on_update)}" if o.on_update
+            sql
+          end
+
+          def visit_DropForeignKey(name)
+            "DROP CONSTRAINT #{quote_column_name(name)}"
+          end
+
+          def column_options(o)
+            column_options = {}
+            column_options[:null] = o.null unless o.null.nil?
+            column_options[:default] = o.default unless o.default.nil?
+            column_options[:column] = o
+            column_options[:first] = o.first
+            column_options[:after] = o.after
+            column_options
+          end
+
+          def quote_column_name(name)
+            @conn.quote_column_name name
+          end
+
+          def quote_table_name(name)
+            @conn.quote_table_name name
+          end
+
+          def type_to_sql(type, limit, precision, scale)
+            @conn.type_to_sql type.to_sym, limit, precision, scale
+          end
+
+          def add_column_options!(sql, options)
+            sql << " DEFAULT #{quote_value(options[:default], options[:column])}" if options_include_default?(options)
+            # must explicitly check for :null to allow change_column to work on migrations
+            if options[:null] == false
+              sql << " NOT NULL"
+            end
+            if options[:auto_increment] == true
+              sql << " AUTO_INCREMENT"
+            end
+            sql
+          end
+
+          def quote_value(value, column)
+            column.sql_type ||= type_to_sql(column.type, column.limit, column.precision, column.scale)
+            column.cast_type ||= type_for_column(column)
+
+            @conn.quote(value, column)
+          end
+
+          def options_include_default?(options)
+            options.include?(:default) && !(options[:null] == false && options[:default].nil?)
+          end
+
+          def action_sql(action, dependency)
+            case dependency
+            when :nullify then "ON #{action} SET NULL"
+            when :cascade  then "ON #{action} CASCADE"
+            when :restrict then "ON #{action} RESTRICT"
+            else
+              raise ArgumentError, <<-MSG.strip_heredoc
+                '#{dependency}' is not supported for :on_update or :on_delete.
+                Supported values are: :nullify, :cascade, :restrict
+              MSG
+            end
+          end
+
+          def type_for_column(column)
+            @conn.lookup_cast_type(column.sql_type)
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
new file mode 100644
index 0000000000..e44ccb7d81
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -0,0 +1,564 @@
+require 'date'
+require 'set'
+require 'bigdecimal'
+require 'bigdecimal/util'
+
+module ActiveRecord
+  module ConnectionAdapters #:nodoc:
+    # Abstract representation of an index definition on a table. Instances of
+    # this type are typically created and returned by methods in database
+    # adapters. e.g. ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter#indexes
+    class IndexDefinition < Struct.new(:table, :name, :unique, :columns, :lengths, :orders, :where, :type, :using) #:nodoc:
+    end
+
+    # Abstract representation of a column definition. Instances of this type
+    # are typically created by methods in TableDefinition, and added to the
+    # +columns+ attribute of said TableDefinition object, in order to be used
+    # for generating a number of table creation or table changing SQL statements.
+    class ColumnDefinition < Struct.new(:name, :type, :limit, :precision, :scale, :default, :null, :first, :after, :primary_key, :sql_type, :cast_type) #:nodoc:
+
+      def primary_key?
+        primary_key || type.to_sym == :primary_key
+      end
+    end
+
+    class ChangeColumnDefinition < Struct.new(:column, :type, :options) #:nodoc:
+    end
+
+    class ForeignKeyDefinition < Struct.new(:from_table, :to_table, :options) #:nodoc:
+      def name
+        options[:name]
+      end
+
+      def column
+        options[:column]
+      end
+
+      def primary_key
+        options[:primary_key] || default_primary_key
+      end
+
+      def on_delete
+        options[:on_delete]
+      end
+
+      def on_update
+        options[:on_update]
+      end
+
+      def custom_primary_key?
+        options[:primary_key] != default_primary_key
+      end
+
+      private
+      def default_primary_key
+        "id"
+      end
+    end
+
+    # Represents the schema of an SQL table in an abstract way. This class
+    # provides methods for manipulating the schema representation.
+    #
+    # Inside migration files, the +t+ object in +create_table+
+    # is actually of this type:
+    #
+    #   class SomeMigration < ActiveRecord::Migration
+    #     def up
+    #       create_table :foo do |t|
+    #         puts t.class  # => "ActiveRecord::ConnectionAdapters::TableDefinition"
+    #       end
+    #     end
+    #
+    #     def down
+    #       ...
+    #     end
+    #   end
+    #
+    # The table definitions
+    # The Columns are stored as a ColumnDefinition in the +columns+ attribute.
+    class TableDefinition
+      # An array of ColumnDefinition objects, representing the column changes
+      # that have been defined.
+      attr_accessor :indexes
+      attr_reader :name, :temporary, :options, :as
+
+      def initialize(types, name, temporary, options, as = nil)
+        @columns_hash = {}
+        @indexes = {}
+        @native = types
+        @temporary = temporary
+        @options = options
+        @as = as
+        @name = name
+      end
+
+      def columns; @columns_hash.values; end
+
+      # Appends a primary key definition to the table definition.
+      # Can be called multiple times, but this is probably not a good idea.
+      def primary_key(name, type = :primary_key, options = {})
+        column(name, type, options.merge(:primary_key => true))
+      end
+
+      # Returns a ColumnDefinition for the column with name +name+.
+      def [](name)
+        @columns_hash[name.to_s]
+      end
+
+      # Instantiates a new column for the table.
+      # The +type+ parameter is normally one of the migrations native types,
+      # which is one of the following:
+      # <tt>:primary_key</tt>, <tt>:string</tt>, <tt>:text</tt>,
+      # <tt>:integer</tt>, <tt>:float</tt>, <tt>:decimal</tt>,
+      # <tt>:datetime</tt>, <tt>:timestamp</tt>, <tt>:time</tt>,
+      # <tt>:date</tt>, <tt>:binary</tt>, <tt>:boolean</tt>.
+      #
+      # You may use a type not in this list as long as it is supported by your
+      # database (for example, "polygon" in MySQL), but this will not be database
+      # agnostic and should usually be avoided.
+      #
+      # Available options are (none of these exists by default):
+      # * <tt>:limit</tt> -
+      #   Requests a maximum column length. This is number of characters for <tt>:string</tt> and
+      #   <tt>:text</tt> columns and number of bytes for <tt>:binary</tt> and <tt>:integer</tt> columns.
+      # * <tt>:default</tt> -
+      #   The column's default value. Use nil for NULL.
+      # * <tt>:null</tt> -
+      #   Allows or disallows +NULL+ values in the column. This option could
+      #   have been named <tt>:null_allowed</tt>.
+      # * <tt>:precision</tt> -
+      #   Specifies the precision for a <tt>:decimal</tt> column.
+      # * <tt>:scale</tt> -
+      #   Specifies the scale for a <tt>:decimal</tt> column.
+      # * <tt>:index</tt> -
+      #   Create an index for the column. Can be either <tt>true</tt> or an options hash.
+      #
+      # Note: The precision is the total number of significant digits
+      # and the scale is the number of digits that can be stored following
+      # the decimal point. For example, the number 123.45 has a precision of 5
+      # and a scale of 2. A decimal with a precision of 5 and a scale of 2 can
+      # range from -999.99 to 999.99.
+      #
+      # Please be aware of different RDBMS implementations behavior with
+      # <tt>:decimal</tt> columns:
+      # * The SQL standard says the default scale should be 0, <tt>:scale</tt> <=
+      #   <tt>:precision</tt>, and makes no comments about the requirements of
+      #   <tt>:precision</tt>.
+      # * MySQL: <tt>:precision</tt> [1..63], <tt>:scale</tt> [0..30].
+      #   Default is (10,0).
+      # * PostgreSQL: <tt>:precision</tt> [1..infinity],
+      #   <tt>:scale</tt> [0..infinity]. No default.
+      # * SQLite2: Any <tt>:precision</tt> and <tt>:scale</tt> may be used.
+      #   Internal storage as strings. No default.
+      # * SQLite3: No restrictions on <tt>:precision</tt> and <tt>:scale</tt>,
+      #   but the maximum supported <tt>:precision</tt> is 16. No default.
+      # * Oracle: <tt>:precision</tt> [1..38], <tt>:scale</tt> [-84..127].
+      #   Default is (38,0).
+      # * DB2: <tt>:precision</tt> [1..63], <tt>:scale</tt> [0..62].
+      #   Default unknown.
+      # * SqlServer?: <tt>:precision</tt> [1..38], <tt>:scale</tt> [0..38].
+      #   Default (38,0).
+      #
+      # This method returns <tt>self</tt>.
+      #
+      # == Examples
+      #  # Assuming +td+ is an instance of TableDefinition
+      #  td.column(:granted, :boolean)
+      #  # granted BOOLEAN
+      #
+      #  td.column(:picture, :binary, limit: 2.megabytes)
+      #  # => picture BLOB(2097152)
+      #
+      #  td.column(:sales_stage, :string, limit: 20, default: 'new', null: false)
+      #  # => sales_stage VARCHAR(20) DEFAULT 'new' NOT NULL
+      #
+      #  td.column(:bill_gates_money, :decimal, precision: 15, scale: 2)
+      #  # => bill_gates_money DECIMAL(15,2)
+      #
+      #  td.column(:sensor_reading, :decimal, precision: 30, scale: 20)
+      #  # => sensor_reading DECIMAL(30,20)
+      #
+      #  # While <tt>:scale</tt> defaults to zero on most databases, it
+      #  # probably wouldn't hurt to include it.
+      #  td.column(:huge_integer, :decimal, precision: 30)
+      #  # => huge_integer DECIMAL(30)
+      #
+      #  # Defines a column with a database-specific type.
+      #  td.column(:foo, 'polygon')
+      #  # => foo polygon
+      #
+      # == Short-hand examples
+      #
+      # Instead of calling +column+ directly, you can also work with the short-hand definitions for the default types.
+      # They use the type as the method name instead of as a parameter and allow for multiple columns to be defined
+      # in a single statement.
+      #
+      # What can be written like this with the regular calls to column:
+      #
+      #   create_table :products do |t|
+      #     t.column :shop_id,     :integer
+      #     t.column :creator_id,  :integer
+      #     t.column :item_number, :string
+      #     t.column :name,        :string, default: "Untitled"
+      #     t.column :value,       :string, default: "Untitled"
+      #     t.column :created_at,  :datetime
+      #     t.column :updated_at,  :datetime
+      #   end
+      #   add_index :products, :item_number
+      #
+      # can also be written as follows using the short-hand:
+      #
+      #   create_table :products do |t|
+      #     t.integer :shop_id, :creator_id
+      #     t.string  :item_number, index: true
+      #     t.string  :name, :value, default: "Untitled"
+      #     t.timestamps
+      #   end
+      #
+      # There's a short-hand method for each of the type values declared at the top. And then there's
+      # TableDefinition#timestamps that'll add +created_at+ and +updated_at+ as datetimes.
+      #
+      # TableDefinition#references will add an appropriately-named _id column, plus a corresponding _type
+      # column if the <tt>:polymorphic</tt> option is supplied. If <tt>:polymorphic</tt> is a hash of
+      # options, these will be used when creating the <tt>_type</tt> column. The <tt>:index</tt> option
+      # will also create an index, similar to calling <tt>add_index</tt>. So what can be written like this:
+      #
+      #   create_table :taggings do |t|
+      #     t.integer :tag_id, :tagger_id, :taggable_id
+      #     t.string  :tagger_type
+      #     t.string  :taggable_type, default: 'Photo'
+      #   end
+      #   add_index :taggings, :tag_id, name: 'index_taggings_on_tag_id'
+      #   add_index :taggings, [:tagger_id, :tagger_type]
+      #
+      # Can also be written as follows using references:
+      #
+      #   create_table :taggings do |t|
+      #     t.references :tag, index: { name: 'index_taggings_on_tag_id' }
+      #     t.references :tagger, polymorphic: true, index: true
+      #     t.references :taggable, polymorphic: { default: 'Photo' }
+      #   end
+      def column(name, type, options = {})
+        name = name.to_s
+        type = type.to_sym
+
+        if primary_key_column_name == name
+          raise ArgumentError, "you can't redefine the primary key column '#{name}'. To define a custom primary key, pass { id: false } to create_table."
+        end
+
+        index_options = options.delete(:index)
+        index(name, index_options.is_a?(Hash) ? index_options : {}) if index_options
+        @columns_hash[name] = new_column_definition(name, type, options)
+        self
+      end
+
+      def remove_column(name)
+        @columns_hash.delete name.to_s
+      end
+
+      [:string, :text, :integer, :float, :decimal, :datetime, :timestamp, :time, :date, :binary, :boolean].each do |column_type|
+        define_method column_type do |*args|
+          options = args.extract_options!
+          column_names = args
+          column_names.each { |name| column(name, column_type, options) }
+        end
+      end
+
+      # Adds index options to the indexes hash, keyed by column name
+      # This is primarily used to track indexes that need to be created after the table
+      #
+      #   index(:account_id, name: 'index_projects_on_account_id')
+      def index(column_name, options = {})
+        indexes[column_name] = options
+      end
+
+      # Appends <tt>:datetime</tt> columns <tt>:created_at</tt> and
+      # <tt>:updated_at</tt> to the table.
+      def timestamps(*args)
+        options = args.extract_options!
+        column(:created_at, :datetime, options)
+        column(:updated_at, :datetime, options)
+      end
+
+      # Adds a reference. Optionally adds a +type+ column, if <tt>:polymorphic</tt> option is provided.
+      # <tt>references</tt> and <tt>belongs_to</tt> are acceptable. The reference column will be an +integer+
+      # by default, the <tt>:type</tt> option can be used to specify a different type.
+      #
+      #  t.references(:user)
+      #  t.references(:user, type: "string")
+      #  t.belongs_to(:supplier, polymorphic: true)
+      #
+      # See SchemaStatements#add_reference
+      def references(*args)
+        options = args.extract_options!
+        polymorphic = options.delete(:polymorphic)
+        index_options = options.delete(:index)
+        type = options.delete(:type) || :integer
+        args.each do |col|
+          column("#{col}_id", type, options)
+          column("#{col}_type", :string, polymorphic.is_a?(Hash) ? polymorphic : options) if polymorphic
+          index(polymorphic ? %w(id type).map { |t| "#{col}_#{t}" } : "#{col}_id", index_options.is_a?(Hash) ? index_options : {}) if index_options
+        end
+      end
+      alias :belongs_to :references
+
+      def new_column_definition(name, type, options) # :nodoc:
+        type = aliased_types[type] || type
+        column = create_column_definition name, type
+        limit = options.fetch(:limit) do
+          native[type][:limit] if native[type].is_a?(Hash)
+        end
+
+        column.limit       = limit
+        column.array       = options[:array] if column.respond_to?(:array)
+        column.precision   = options[:precision]
+        column.scale       = options[:scale]
+        column.default     = options[:default]
+        column.null        = options[:null]
+        column.first       = options[:first]
+        column.after       = options[:after]
+        column.primary_key = type == :primary_key || options[:primary_key]
+        column
+      end
+
+      private
+      def create_column_definition(name, type)
+        ColumnDefinition.new name, type
+      end
+
+      def primary_key_column_name
+        primary_key_column = columns.detect { |c| c.primary_key? }
+        primary_key_column && primary_key_column.name
+      end
+
+      def native
+        @native
+      end
+
+      def aliased_types
+        HashWithIndifferentAccess.new(
+          timestamp: :datetime,
+        )
+      end
+    end
+
+    class AlterTable # :nodoc:
+      attr_reader :adds
+      attr_reader :foreign_key_adds
+      attr_reader :foreign_key_drops
+
+      def initialize(td)
+        @td   = td
+        @adds = []
+        @foreign_key_adds = []
+        @foreign_key_drops = []
+      end
+
+      def name; @td.name; end
+
+      def add_foreign_key(to_table, options)
+        @foreign_key_adds << ForeignKeyDefinition.new(name, to_table, options)
+      end
+
+      def drop_foreign_key(name)
+        @foreign_key_drops << name
+      end
+
+      def add_column(name, type, options)
+        name = name.to_s
+        type = type.to_sym
+        @adds << @td.new_column_definition(name, type, options)
+      end
+    end
+
+    # Represents an SQL table in an abstract way for updating a table.
+    # Also see TableDefinition and SchemaStatements#create_table
+    #
+    # Available transformations are:
+    #
+    #   change_table :table do |t|
+    #     t.column
+    #     t.index
+    #     t.rename_index
+    #     t.timestamps
+    #     t.change
+    #     t.change_default
+    #     t.rename
+    #     t.references
+    #     t.belongs_to
+    #     t.string
+    #     t.text
+    #     t.integer
+    #     t.float
+    #     t.decimal
+    #     t.datetime
+    #     t.timestamp
+    #     t.time
+    #     t.date
+    #     t.binary
+    #     t.boolean
+    #     t.remove
+    #     t.remove_references
+    #     t.remove_belongs_to
+    #     t.remove_index
+    #     t.remove_timestamps
+    #   end
+    #
+    class Table
+      def initialize(table_name, base)
+        @table_name = table_name
+        @base = base
+      end
+
+      # Adds a new column to the named table.
+      # See TableDefinition#column for details of the options you can use.
+      #
+      # ====== Creating a simple column
+      #  t.column(:name, :string)
+      def column(column_name, type, options = {})
+        @base.add_column(@table_name, column_name, type, options)
+      end
+
+      # Checks to see if a column exists. See SchemaStatements#column_exists?
+      def column_exists?(column_name, type = nil, options = {})
+        @base.column_exists?(@table_name, column_name, type, options)
+      end
+
+      # Adds a new index to the table. +column_name+ can be a single Symbol, or
+      # an Array of Symbols. See SchemaStatements#add_index
+      #
+      # ====== Creating a simple index
+      #  t.index(:name)
+      # ====== Creating a unique index
+      #  t.index([:branch_id, :party_id], unique: true)
+      # ====== Creating a named index
+      #  t.index([:branch_id, :party_id], unique: true, name: 'by_branch_party')
+      def index(column_name, options = {})
+        @base.add_index(@table_name, column_name, options)
+      end
+
+      # Checks to see if an index exists. See SchemaStatements#index_exists?
+      def index_exists?(column_name, options = {})
+        @base.index_exists?(@table_name, column_name, options)
+      end
+
+      # Renames the given index on the table.
+      #
+      #  t.rename_index(:user_id, :account_id)
+      def rename_index(index_name, new_index_name)
+        @base.rename_index(@table_name, index_name, new_index_name)
+      end
+
+      # Adds timestamps (+created_at+ and +updated_at+) columns to the table. See SchemaStatements#add_timestamps
+      #
+      #  t.timestamps
+      def timestamps
+        @base.add_timestamps(@table_name)
+      end
+
+      # Changes the column's definition according to the new options.
+      # See TableDefinition#column for details of the options you can use.
+      #
+      #  t.change(:name, :string, limit: 80)
+      #  t.change(:description, :text)
+      def change(column_name, type, options = {})
+        @base.change_column(@table_name, column_name, type, options)
+      end
+
+      # Sets a new default value for a column. See SchemaStatements#change_column_default
+      #
+      #  t.change_default(:qualification, 'new')
+      #  t.change_default(:authorized, 1)
+      def change_default(column_name, default)
+        @base.change_column_default(@table_name, column_name, default)
+      end
+
+      # Removes the column(s) from the table definition.
+      #
+      #  t.remove(:qualification)
+      #  t.remove(:qualification, :experience)
+      def remove(*column_names)
+        @base.remove_columns(@table_name, *column_names)
+      end
+
+      # Removes the given index from the table.
+      #
+      # ====== Remove the index_table_name_on_column in the table_name table
+      #   t.remove_index :column
+      # ====== Remove the index named index_table_name_on_branch_id in the table_name table
+      #   t.remove_index column: :branch_id
+      # ====== Remove the index named index_table_name_on_branch_id_and_party_id in the table_name table
+      #   t.remove_index column: [:branch_id, :party_id]
+      # ====== Remove the index named by_branch_party in the table_name table
+      #   t.remove_index name: :by_branch_party
+      def remove_index(options = {})
+        @base.remove_index(@table_name, options)
+      end
+
+      # Removes the timestamp columns (+created_at+ and +updated_at+) from the table.
+      #
+      #  t.remove_timestamps
+      def remove_timestamps
+        @base.remove_timestamps(@table_name)
+      end
+
+      # Renames a column.
+      #
+      #  t.rename(:description, :name)
+      def rename(column_name, new_column_name)
+        @base.rename_column(@table_name, column_name, new_column_name)
+      end
+
+      # Adds a reference. Optionally adds a +type+ column, if <tt>:polymorphic</tt> option is provided.
+      # <tt>references</tt> and <tt>belongs_to</tt> are acceptable. The reference column will be an +integer+
+      # by default, the <tt>:type</tt> option can be used to specify a different type.
+      #
+      #  t.references(:user)
+      #  t.references(:user, type: "string")
+      #  t.belongs_to(:supplier, polymorphic: true)
+      #
+      # See SchemaStatements#add_reference
+      def references(*args)
+        options = args.extract_options!
+        args.each do |ref_name|
+          @base.add_reference(@table_name, ref_name, options)
+        end
+      end
+      alias :belongs_to :references
+
+      # Removes a reference. Optionally removes a +type+ column.
+      # <tt>remove_references</tt> and <tt>remove_belongs_to</tt> are acceptable.
+      #
+      #  t.remove_references(:user)
+      #  t.remove_belongs_to(:supplier, polymorphic: true)
+      #
+      # See SchemaStatements#remove_reference
+      def remove_references(*args)
+        options = args.extract_options!
+        args.each do |ref_name|
+          @base.remove_reference(@table_name, ref_name, options)
+        end
+      end
+      alias :remove_belongs_to :remove_references
+
+      # Adds a column or columns of a specified type
+      #
+      #  t.string(:goat)
+      #  t.string(:goat, :sheep)
+      [:string, :text, :integer, :float, :decimal, :datetime, :timestamp, :time, :date, :binary, :boolean].each do |column_type|
+        define_method column_type do |*args|
+          options = args.extract_options!
+          args.each do |name|
+            @base.add_column(@table_name, name, column_type, options)
+          end
+        end
+      end
+
+      private
+        def native
+          @base.native_database_types
+        end
+    end
+
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
new file mode 100644
index 0000000000..9bd0401e40
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
@@ -0,0 +1,46 @@
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    # The goal of this module is to move Adapter specific column
+    # definitions to the Adapter instead of having it in the schema
+    # dumper itself. This code represents the normal case.
+    # We can then redefine how certain data types may be handled in the schema dumper on the
+    # Adapter level by over-writing this code inside the database specific adapters
+    module ColumnDumper
+      def column_spec(column, types)
+        spec = prepare_column_options(column, types)
+        (spec.keys - [:name, :type]).each{ |k| spec[k].insert(0, "#{k.to_s}: ")}
+        spec
+      end
+
+      # This can be overridden on a Adapter level basis to support other
+      # extended datatypes (Example: Adding an array option in the
+      # PostgreSQLAdapter)
+      def prepare_column_options(column, types)
+        spec = {}
+        spec[:name]      = column.name.inspect
+        spec[:type]      = column.type.to_s
+        spec[:limit]     = column.limit.inspect if column.limit != types[column.type][:limit]
+        spec[:precision] = column.precision.inspect if column.precision
+        spec[:scale]     = column.scale.inspect if column.scale
+        spec[:null]      = 'false' unless column.null
+        spec[:default]   = schema_default(column) if column.has_default?
+        spec.delete(:default) if spec[:default].nil?
+        spec
+      end
+
+      # Lists the valid migration options
+      def migration_keys
+        [:name, :limit, :precision, :scale, :default, :null]
+      end
+
+      private
+
+      def schema_default(column)
+        default = column.type_cast_from_database(column.default)
+        unless default.nil?
+          column.type_cast_for_schema(default)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
new file mode 100644
index 0000000000..10753defc2
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -0,0 +1,979 @@
+require 'active_record/migration/join_table'
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    module SchemaStatements
+      include ActiveRecord::Migration::JoinTable
+
+      # Returns a hash of mappings from the abstract data types to the native
+      # database types. See TableDefinition#column for details on the recognized
+      # abstract data types.
+      def native_database_types
+        {}
+      end
+
+      # Truncates a table alias according to the limits of the current adapter.
+      def table_alias_for(table_name)
+        table_name[0...table_alias_length].tr('.', '_')
+      end
+
+      # Checks to see if the table +table_name+ exists on the database.
+      #
+      #   table_exists?(:developers)
+      #
+      def table_exists?(table_name)
+        tables.include?(table_name.to_s)
+      end
+
+      # Returns an array of indexes for the given table.
+      # def indexes(table_name, name = nil) end
+
+      # Checks to see if an index exists on a table for a given index definition.
+      #
+      #   # Check an index exists
+      #   index_exists?(:suppliers, :company_id)
+      #
+      #   # Check an index on multiple columns exists
+      #   index_exists?(:suppliers, [:company_id, :company_type])
+      #
+      #   # Check a unique index exists
+      #   index_exists?(:suppliers, :company_id, unique: true)
+      #
+      #   # Check an index with a custom name exists
+      #   index_exists?(:suppliers, :company_id, name: "idx_company_id")
+      #
+      def index_exists?(table_name, column_name, options = {})
+        column_names = Array(column_name)
+        index_name = options.key?(:name) ? options[:name].to_s : index_name(table_name, :column => column_names)
+        if options[:unique]
+          indexes(table_name).any?{ |i| i.unique && i.name == index_name }
+        else
+          indexes(table_name).any?{ |i| i.name == index_name }
+        end
+      end
+
+      # Returns an array of Column objects for the table specified by +table_name+.
+      # See the concrete implementation for details on the expected parameter values.
+      def columns(table_name) end
+
+      # Checks to see if a column exists in a given table.
+      #
+      #   # Check a column exists
+      #   column_exists?(:suppliers, :name)
+      #
+      #   # Check a column exists of a particular type
+      #   column_exists?(:suppliers, :name, :string)
+      #
+      #   # Check a column exists with a specific definition
+      #   column_exists?(:suppliers, :name, :string, limit: 100)
+      #   column_exists?(:suppliers, :name, :string, default: 'default')
+      #   column_exists?(:suppliers, :name, :string, null: false)
+      #   column_exists?(:suppliers, :tax, :decimal, precision: 8, scale: 2)
+      #
+      def column_exists?(table_name, column_name, type = nil, options = {})
+        column_name = column_name.to_s
+        columns(table_name).any?{ |c| c.name == column_name &&
+                                      (!type                     || c.type == type) &&
+                                      (!options.key?(:limit)     || c.limit == options[:limit]) &&
+                                      (!options.key?(:precision) || c.precision == options[:precision]) &&
+                                      (!options.key?(:scale)     || c.scale == options[:scale]) &&
+                                      (!options.key?(:default)   || c.default == options[:default]) &&
+                                      (!options.key?(:null)      || c.null == options[:null]) }
+      end
+
+      # Creates a new table with the name +table_name+. +table_name+ may either
+      # be a String or a Symbol.
+      #
+      # There are two ways to work with +create_table+. You can use the block
+      # form or the regular form, like this:
+      #
+      # === Block form
+      #
+      #   # create_table() passes a TableDefinition object to the block.
+      #   # This form will not only create the table, but also columns for the
+      #   # table.
+      #
+      #   create_table(:suppliers) do |t|
+      #     t.column :name, :string, limit: 60
+      #     # Other fields here
+      #   end
+      #
+      # === Block form, with shorthand
+      #
+      #   # You can also use the column types as method calls, rather than calling the column method.
+      #   create_table(:suppliers) do |t|
+      #     t.string :name, limit: 60
+      #     # Other fields here
+      #   end
+      #
+      # === Regular form
+      #
+      #   # Creates a table called 'suppliers' with no columns.
+      #   create_table(:suppliers)
+      #   # Add a column to 'suppliers'.
+      #   add_column(:suppliers, :name, :string, {limit: 60})
+      #
+      # The +options+ hash can include the following keys:
+      # [<tt>:id</tt>]
+      #   Whether to automatically add a primary key column. Defaults to true.
+      #   Join tables for +has_and_belongs_to_many+ should set it to false.
+      # [<tt>:primary_key</tt>]
+      #   The name of the primary key, if one is to be added automatically.
+      #   Defaults to +id+. If <tt>:id</tt> is false this option is ignored.
+      #
+      #   Note that Active Record models will automatically detect their
+      #   primary key. This can be avoided by using +self.primary_key=+ on the model
+      #   to define the key explicitly.
+      #
+      # [<tt>:options</tt>]
+      #   Any extra options you want appended to the table definition.
+      # [<tt>:temporary</tt>]
+      #   Make a temporary table.
+      # [<tt>:force</tt>]
+      #   Set to true to drop the table before creating it.
+      #   Defaults to false.
+      # [<tt>:as</tt>]
+      #   SQL to use to generate the table. When this option is used, the block is
+      #   ignored, as are the <tt>:id</tt> and <tt>:primary_key</tt> options.
+      #
+      # ====== Add a backend specific option to the generated SQL (MySQL)
+      #
+      #   create_table(:suppliers, options: 'ENGINE=InnoDB DEFAULT CHARSET=utf8')
+      #
+      # generates:
+      #
+      #   CREATE TABLE suppliers (
+      #     id int(11) DEFAULT NULL auto_increment PRIMARY KEY
+      #   ) ENGINE=InnoDB DEFAULT CHARSET=utf8
+      #
+      # ====== Rename the primary key column
+      #
+      #   create_table(:objects, primary_key: 'guid') do |t|
+      #     t.column :name, :string, limit: 80
+      #   end
+      #
+      # generates:
+      #
+      #   CREATE TABLE objects (
+      #     guid int(11) DEFAULT NULL auto_increment PRIMARY KEY,
+      #     name varchar(80)
+      #   )
+      #
+      # ====== Do not add a primary key column
+      #
+      #   create_table(:categories_suppliers, id: false) do |t|
+      #     t.column :category_id, :integer
+      #     t.column :supplier_id, :integer
+      #   end
+      #
+      # generates:
+      #
+      #   CREATE TABLE categories_suppliers (
+      #     category_id int,
+      #     supplier_id int
+      #   )
+      #
+      # ====== Create a temporary table based on a query
+      #
+      #   create_table(:long_query, temporary: true,
+      #     as: "SELECT * FROM orders INNER JOIN line_items ON order_id=orders.id")
+      #
+      # generates:
+      #
+      #   CREATE TEMPORARY TABLE long_query AS
+      #     SELECT * FROM orders INNER JOIN line_items ON order_id=orders.id
+      #
+      # See also TableDefinition#column for details on how to create columns.
+      def create_table(table_name, options = {})
+        td = create_table_definition table_name, options[:temporary], options[:options], options[:as]
+
+        if options[:id] != false && !options[:as]
+          pk = options.fetch(:primary_key) do
+            Base.get_primary_key table_name.to_s.singularize
+          end
+
+          td.primary_key pk, options.fetch(:id, :primary_key), options
+        end
+
+        yield td if block_given?
+
+        if options[:force] && table_exists?(table_name)
+          drop_table(table_name, options)
+        end
+
+        result = execute schema_creation.accept td
+        td.indexes.each_pair { |c, o| add_index(table_name, c, o) } unless supports_indexes_in_create?
+        result
+      end
+
+      # Creates a new join table with the name created using the lexical order of the first two
+      # arguments. These arguments can be a String or a Symbol.
+      #
+      #   # Creates a table called 'assemblies_parts' with no id.
+      #   create_join_table(:assemblies, :parts)
+      #
+      # You can pass a +options+ hash can include the following keys:
+      # [<tt>:table_name</tt>]
+      #   Sets the table name overriding the default
+      # [<tt>:column_options</tt>]
+      #   Any extra options you want appended to the columns definition.
+      # [<tt>:options</tt>]
+      #   Any extra options you want appended to the table definition.
+      # [<tt>:temporary</tt>]
+      #   Make a temporary table.
+      # [<tt>:force</tt>]
+      #   Set to true to drop the table before creating it.
+      #   Defaults to false.
+      #
+      # Note that +create_join_table+ does not create any indices by default; you can use
+      # its block form to do so yourself:
+      #
+      #   create_join_table :products, :categories do |t|
+      #     t.index :product_id
+      #     t.index :category_id
+      #   end
+      #
+      # ====== Add a backend specific option to the generated SQL (MySQL)
+      #
+      #   create_join_table(:assemblies, :parts, options: 'ENGINE=InnoDB DEFAULT CHARSET=utf8')
+      #
+      # generates:
+      #
+      #   CREATE TABLE assemblies_parts (
+      #     assembly_id int NOT NULL,
+      #     part_id int NOT NULL,
+      #   ) ENGINE=InnoDB DEFAULT CHARSET=utf8
+      #
+      def create_join_table(table_1, table_2, options = {})
+        join_table_name = find_join_table_name(table_1, table_2, options)
+
+        column_options = options.delete(:column_options) || {}
+        column_options.reverse_merge!(null: false)
+
+        t1_column, t2_column = [table_1, table_2].map{ |t| t.to_s.singularize.foreign_key }
+
+        create_table(join_table_name, options.merge!(id: false)) do |td|
+          td.integer t1_column, column_options
+          td.integer t2_column, column_options
+          yield td if block_given?
+        end
+      end
+
+      # Drops the join table specified by the given arguments.
+      # See +create_join_table+ for details.
+      #
+      # Although this command ignores the block if one is given, it can be helpful
+      # to provide one in a migration's +change+ method so it can be reverted.
+      # In that case, the block will be used by create_join_table.
+      def drop_join_table(table_1, table_2, options = {})
+        join_table_name = find_join_table_name(table_1, table_2, options)
+        drop_table(join_table_name)
+      end
+
+      # A block for changing columns in +table+.
+      #
+      #   # change_table() yields a Table instance
+      #   change_table(:suppliers) do |t|
+      #     t.column :name, :string, limit: 60
+      #     # Other column alterations here
+      #   end
+      #
+      # The +options+ hash can include the following keys:
+      # [<tt>:bulk</tt>]
+      #   Set this to true to make this a bulk alter query, such as
+      #
+      #     ALTER TABLE `users` ADD COLUMN age INT(11), ADD COLUMN birthdate DATETIME ...
+      #
+      #   Defaults to false.
+      #
+      # ====== Add a column
+      #
+      #   change_table(:suppliers) do |t|
+      #     t.column :name, :string, limit: 60
+      #   end
+      #
+      # ====== Add 2 integer columns
+      #
+      #   change_table(:suppliers) do |t|
+      #     t.integer :width, :height, null: false, default: 0
+      #   end
+      #
+      # ====== Add created_at/updated_at columns
+      #
+      #   change_table(:suppliers) do |t|
+      #     t.timestamps
+      #   end
+      #
+      # ====== Add a foreign key column
+      #
+      #   change_table(:suppliers) do |t|
+      #     t.references :company
+      #   end
+      #
+      # Creates a <tt>company_id(integer)</tt> column.
+      #
+      # ====== Add a polymorphic foreign key column
+      #
+      #  change_table(:suppliers) do |t|
+      #    t.belongs_to :company, polymorphic: true
+      #  end
+      #
+      # Creates <tt>company_type(varchar)</tt> and <tt>company_id(integer)</tt> columns.
+      #
+      # ====== Remove a column
+      #
+      #  change_table(:suppliers) do |t|
+      #    t.remove :company
+      #  end
+      #
+      # ====== Remove several columns
+      #
+      #  change_table(:suppliers) do |t|
+      #    t.remove :company_id
+      #    t.remove :width, :height
+      #  end
+      #
+      # ====== Remove an index
+      #
+      #  change_table(:suppliers) do |t|
+      #    t.remove_index :company_id
+      #  end
+      #
+      # See also Table for details on all of the various column transformation.
+      def change_table(table_name, options = {})
+        if supports_bulk_alter? && options[:bulk]
+          recorder = ActiveRecord::Migration::CommandRecorder.new(self)
+          yield update_table_definition(table_name, recorder)
+          bulk_change_table(table_name, recorder.commands)
+        else
+          yield update_table_definition(table_name, self)
+        end
+      end
+
+      # Renames a table.
+      #
+      #   rename_table('octopuses', 'octopi')
+      #
+      def rename_table(table_name, new_name)
+        raise NotImplementedError, "rename_table is not implemented"
+      end
+
+      # Drops a table from the database.
+      #
+      # Although this command ignores +options+ and the block if one is given, it can be helpful
+      # to provide these in a migration's +change+ method so it can be reverted.
+      # In that case, +options+ and the block will be used by create_table.
+      def drop_table(table_name, options = {})
+        execute "DROP TABLE #{quote_table_name(table_name)}"
+      end
+
+      # Adds a new column to the named table.
+      # See TableDefinition#column for details of the options you can use.
+      def add_column(table_name, column_name, type, options = {})
+        at = create_alter_table table_name
+        at.add_column(column_name, type, options)
+        execute schema_creation.accept at
+      end
+
+      # Removes the given columns from the table definition.
+      #
+      #   remove_columns(:suppliers, :qualification, :experience)
+      #
+      def remove_columns(table_name, *column_names)
+        raise ArgumentError.new("You must specify at least one column name. Example: remove_columns(:people, :first_name)") if column_names.empty?
+        column_names.each do |column_name|
+          remove_column(table_name, column_name)
+        end
+      end
+
+      # Removes the column from the table definition.
+      #
+      #   remove_column(:suppliers, :qualification)
+      #
+      # The +type+ and +options+ parameters will be ignored if present. It can be helpful
+      # to provide these in a migration's +change+ method so it can be reverted.
+      # In that case, +type+ and +options+ will be used by add_column.
+      def remove_column(table_name, column_name, type = nil, options = {})
+        execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{quote_column_name(column_name)}"
+      end
+
+      # Changes the column's definition according to the new options.
+      # See TableDefinition#column for details of the options you can use.
+      #
+      #   change_column(:suppliers, :name, :string, limit: 80)
+      #   change_column(:accounts, :description, :text)
+      #
+      def change_column(table_name, column_name, type, options = {})
+        raise NotImplementedError, "change_column is not implemented"
+      end
+
+      # Sets a new default value for a column:
+      #
+      #   change_column_default(:suppliers, :qualification, 'new')
+      #   change_column_default(:accounts, :authorized, 1)
+      #
+      # Setting the default to +nil+ effectively drops the default:
+      #
+      #   change_column_default(:users, :email, nil)
+      #
+      def change_column_default(table_name, column_name, default)
+        raise NotImplementedError, "change_column_default is not implemented"
+      end
+
+      # Sets or removes a +NOT NULL+ constraint on a column. The +null+ flag
+      # indicates whether the value can be +NULL+. For example
+      #
+      #   change_column_null(:users, :nickname, false)
+      #
+      # says nicknames cannot be +NULL+ (adds the constraint), whereas
+      #
+      #   change_column_null(:users, :nickname, true)
+      #
+      # allows them to be +NULL+ (drops the constraint).
+      #
+      # The method accepts an optional fourth argument to replace existing
+      # +NULL+s with some other value. Use that one when enabling the
+      # constraint if needed, since otherwise those rows would not be valid.
+      #
+      # Please note the fourth argument does not set a column's default.
+      def change_column_null(table_name, column_name, null, default = nil)
+        raise NotImplementedError, "change_column_null is not implemented"
+      end
+
+      # Renames a column.
+      #
+      #   rename_column(:suppliers, :description, :name)
+      #
+      def rename_column(table_name, column_name, new_column_name)
+        raise NotImplementedError, "rename_column is not implemented"
+      end
+
+      # Adds a new index to the table. +column_name+ can be a single Symbol, or
+      # an Array of Symbols.
+      #
+      # The index will be named after the table and the column name(s), unless
+      # you pass <tt>:name</tt> as an option.
+      #
+      # ====== Creating a simple index
+      #
+      #   add_index(:suppliers, :name)
+      #
+      # generates:
+      #
+      #   CREATE INDEX suppliers_name_index ON suppliers(name)
+      #
+      # ====== Creating a unique index
+      #
+      #   add_index(:accounts, [:branch_id, :party_id], unique: true)
+      #
+      # generates:
+      #
+      #   CREATE UNIQUE INDEX accounts_branch_id_party_id_index ON accounts(branch_id, party_id)
+      #
+      # ====== Creating a named index
+      #
+      #   add_index(:accounts, [:branch_id, :party_id], unique: true, name: 'by_branch_party')
+      #
+      # generates:
+      #
+      #  CREATE UNIQUE INDEX by_branch_party ON accounts(branch_id, party_id)
+      #
+      # ====== Creating an index with specific key length
+      #
+      #   add_index(:accounts, :name, name: 'by_name', length: 10)
+      #
+      # generates:
+      #
+      #   CREATE INDEX by_name ON accounts(name(10))
+      #
+      #   add_index(:accounts, [:name, :surname], name: 'by_name_surname', length: {name: 10, surname: 15})
+      #
+      # generates:
+      #
+      #   CREATE INDEX by_name_surname ON accounts(name(10), surname(15))
+      #
+      # Note: SQLite doesn't support index length.
+      #
+      # ====== Creating an index with a sort order (desc or asc, asc is the default)
+      #
+      #   add_index(:accounts, [:branch_id, :party_id, :surname], order: {branch_id: :desc, party_id: :asc})
+      #
+      # generates:
+      #
+      #   CREATE INDEX by_branch_desc_party ON accounts(branch_id DESC, party_id ASC, surname)
+      #
+      # Note: MySQL doesn't yet support index order (it accepts the syntax but ignores it).
+      #
+      # ====== Creating a partial index
+      #
+      #   add_index(:accounts, [:branch_id, :party_id], unique: true, where: "active")
+      #
+      # generates:
+      #
+      #   CREATE UNIQUE INDEX index_accounts_on_branch_id_and_party_id ON accounts(branch_id, party_id) WHERE active
+      #
+      # ====== Creating an index with a specific method
+      #
+      #   add_index(:developers, :name, using: 'btree')
+      #
+      # generates:
+      #
+      #   CREATE INDEX index_developers_on_name ON developers USING btree (name) -- PostgreSQL
+      #   CREATE INDEX index_developers_on_name USING btree ON developers (name) -- MySQL
+      #
+      # Note: only supported by PostgreSQL and MySQL
+      #
+      # ====== Creating an index with a specific type
+      #
+      #   add_index(:developers, :name, type: :fulltext)
+      #
+      # generates:
+      #
+      #   CREATE FULLTEXT INDEX index_developers_on_name ON developers (name) -- MySQL
+      #
+      # Note: only supported by MySQL. Supported: <tt>:fulltext</tt> and <tt>:spatial</tt> on MyISAM tables.
+      def add_index(table_name, column_name, options = {})
+        index_name, index_type, index_columns, index_options = add_index_options(table_name, column_name, options)
+        execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{index_columns})#{index_options}"
+      end
+
+      # Removes the given index from the table.
+      #
+      # Removes the +index_accounts_on_column+ in the +accounts+ table.
+      #
+      #   remove_index :accounts, :column
+      #
+      # Removes the index named +index_accounts_on_branch_id+ in the +accounts+ table.
+      #
+      #   remove_index :accounts, column: :branch_id
+      #
+      # Removes the index named +index_accounts_on_branch_id_and_party_id+ in the +accounts+ table.
+      #
+      #   remove_index :accounts, column: [:branch_id, :party_id]
+      #
+      # Removes the index named +by_branch_party+ in the +accounts+ table.
+      #
+      #   remove_index :accounts, name: :by_branch_party
+      #
+      def remove_index(table_name, options = {})
+        remove_index!(table_name, index_name_for_remove(table_name, options))
+      end
+
+      def remove_index!(table_name, index_name) #:nodoc:
+        execute "DROP INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)}"
+      end
+
+      # Renames an index.
+      #
+      # Rename the +index_people_on_last_name+ index to +index_users_on_last_name+:
+      #
+      #   rename_index :people, 'index_people_on_last_name', 'index_users_on_last_name'
+      #
+      def rename_index(table_name, old_name, new_name)
+        # this is a naive implementation; some DBs may support this more efficiently (Postgres, for instance)
+        old_index_def = indexes(table_name).detect { |i| i.name == old_name }
+        return unless old_index_def
+        add_index(table_name, old_index_def.columns, name: new_name, unique: old_index_def.unique)
+        remove_index(table_name, name: old_name)
+      end
+
+      def index_name(table_name, options) #:nodoc:
+        if Hash === options
+          if options[:column]
+            "index_#{table_name}_on_#{Array(options[:column]) * '_and_'}"
+          elsif options[:name]
+            options[:name]
+          else
+            raise ArgumentError, "You must specify the index name"
+          end
+        else
+          index_name(table_name, :column => options)
+        end
+      end
+
+      # Verifies the existence of an index with a given name.
+      #
+      # The default argument is returned if the underlying implementation does not define the indexes method,
+      # as there's no way to determine the correct answer in that case.
+      def index_name_exists?(table_name, index_name, default)
+        return default unless respond_to?(:indexes)
+        index_name = index_name.to_s
+        indexes(table_name).detect { |i| i.name == index_name }
+      end
+
+      # Adds a reference. Optionally adds a +type+ column, if <tt>:polymorphic</tt> option is provided.
+      # The reference column is an +integer+ by default, the <tt>:type</tt> option can be used to specify
+      # a different type.
+      # <tt>add_reference</tt> and <tt>add_belongs_to</tt> are acceptable.
+      #
+      # ====== Create a user_id integer column
+      #
+      #   add_reference(:products, :user)
+      #
+      # ====== Create a user_id string column
+      #
+      #   add_reference(:products, :user, type: :string)
+      #
+      # ====== Create a supplier_id and supplier_type columns
+      #
+      #   add_belongs_to(:products, :supplier, polymorphic: true)
+      #
+      # ====== Create a supplier_id, supplier_type columns and appropriate index
+      #
+      #   add_reference(:products, :supplier, polymorphic: true, index: true)
+      #
+      def add_reference(table_name, ref_name, options = {})
+        polymorphic = options.delete(:polymorphic)
+        index_options = options.delete(:index)
+        type = options.delete(:type) || :integer
+        add_column(table_name, "#{ref_name}_id", type, options)
+        add_column(table_name, "#{ref_name}_type", :string, polymorphic.is_a?(Hash) ? polymorphic : options) if polymorphic
+        add_index(table_name, polymorphic ? %w[id type].map{ |t| "#{ref_name}_#{t}" } : "#{ref_name}_id", index_options.is_a?(Hash) ? index_options : {}) if index_options
+      end
+      alias :add_belongs_to :add_reference
+
+      # Removes the reference(s). Also removes a +type+ column if one exists.
+      # <tt>remove_reference</tt>, <tt>remove_references</tt> and <tt>remove_belongs_to</tt> are acceptable.
+      #
+      # ====== Remove the reference
+      #
+      #   remove_reference(:products, :user, index: true)
+      #
+      # ====== Remove polymorphic reference
+      #
+      #   remove_reference(:products, :supplier, polymorphic: true)
+      #
+      def remove_reference(table_name, ref_name, options = {})
+        remove_column(table_name, "#{ref_name}_id")
+        remove_column(table_name, "#{ref_name}_type") if options[:polymorphic]
+      end
+      alias :remove_belongs_to :remove_reference
+
+      # Returns an array of foreign keys for the given table.
+      # The foreign keys are represented as +ForeignKeyDefinition+ objects.
+      def foreign_keys(table_name)
+        raise NotImplementedError, "foreign_keys is not implemented"
+      end
+
+      # Adds a new foreign key. +from_table+ is the table with the key column,
+      # +to_table+ contains the referenced primary key.
+      #
+      # The foreign key will be named after the following pattern: <tt>fk_rails_<identifier></tt>.
+      # +identifier+ is a 10 character long random string. A custom name can be specified with
+      # the <tt>:name</tt> option.
+      #
+      # ====== Creating a simple foreign key
+      #
+      #   add_foreign_key :articles, :authors
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT articles_author_id_fk FOREIGN KEY ("author_id") REFERENCES "authors" ("id")
+      #
+      # ====== Creating a foreign key on a specific column
+      #
+      #   add_foreign_key :articles, :users, column: :author_id, primary_key: "lng_id"
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT fk_rails_58ca3d3a82 FOREIGN KEY ("author_id") REFERENCES "users" ("lng_id")
+      #
+      # ====== Creating a cascading foreign key
+      #
+      #   add_foreign_key :articles, :authors, on_delete: :cascade
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT articles_author_id_fk FOREIGN KEY ("author_id") REFERENCES "authors" ("id") ON DELETE CASCADE
+      #
+      # The +options+ hash can include the following keys:
+      # [<tt>:column</tt>]
+      #   The foreign key column name on +from_table+. Defaults to <tt>to_table.singularize + "_id"</tt>
+      # [<tt>:primary_key</tt>]
+      #   The primary key column name on +to_table+. Defaults to +id+.
+      # [<tt>:name</tt>]
+      #   The constraint name. Defaults to <tt>fk_rails_<identifier></tt>.
+      # [<tt>:on_delete</tt>]
+      #   Action that happens <tt>ON DELETE</tt>. Valid values are +:nullify+, +:cascade:+ and +:restrict+
+      # [<tt>:on_update</tt>]
+      #   Action that happens <tt>ON UPDATE</tt>. Valid values are +:nullify+, +:cascade:+ and +:restrict+
+      def add_foreign_key(from_table, to_table, options = {})
+        return unless supports_foreign_keys?
+
+        options[:column] ||= foreign_key_column_for(to_table)
+
+        options = {
+          column: options[:column],
+          primary_key: options[:primary_key],
+          name: foreign_key_name(from_table, options),
+          on_delete: options[:on_delete],
+          on_update: options[:on_update]
+        }
+        at = create_alter_table from_table
+        at.add_foreign_key to_table, options
+
+        execute schema_creation.accept(at)
+      end
+
+      # Removes the given foreign key from the table.
+      #
+      # Removes the foreign key on +accounts.branch_id+.
+      #
+      #   remove_foreign_key :accounts, :branches
+      #
+      # Removes the foreign key on +accounts.owner_id+.
+      #
+      #   remove_foreign_key :accounts, column: :owner_id
+      #
+      # Removes the foreign key named +special_fk_name+ on the +accounts+ table.
+      #
+      #   remove_foreign_key :accounts, name: :special_fk_name
+      #
+      def remove_foreign_key(from_table, options_or_to_table = {})
+        return unless supports_foreign_keys?
+
+        if options_or_to_table.is_a?(Hash)
+          options = options_or_to_table
+        else
+          options = { column: foreign_key_column_for(options_or_to_table) }
+        end
+
+        fk_name_to_delete = options.fetch(:name) do
+          fk_to_delete = foreign_keys(from_table).detect {|fk| fk.column == options[:column] }
+
+          if fk_to_delete
+            fk_to_delete.name
+          else
+            raise ArgumentError, "Table '#{from_table}' has no foreign key on column '#{options[:column]}'"
+          end
+        end
+
+        at = create_alter_table from_table
+        at.drop_foreign_key fk_name_to_delete
+
+        execute schema_creation.accept(at)
+      end
+
+      def foreign_key_column_for(table_name) # :nodoc:
+        "#{table_name.to_s.singularize}_id"
+      end
+
+      def dump_schema_information #:nodoc:
+        sm_table = ActiveRecord::Migrator.schema_migrations_table_name
+
+        ActiveRecord::SchemaMigration.order('version').map { |sm|
+          "INSERT INTO #{sm_table} (version) VALUES ('#{sm.version}');"
+        }.join "\n\n"
+      end
+
+      # Should not be called normally, but this operation is non-destructive.
+      # The migrations module handles this automatically.
+      def initialize_schema_migrations_table
+        ActiveRecord::SchemaMigration.create_table
+      end
+
+      def assume_migrated_upto_version(version, migrations_paths = ActiveRecord::Migrator.migrations_paths)
+        migrations_paths = Array(migrations_paths)
+        version = version.to_i
+        sm_table = quote_table_name(ActiveRecord::Migrator.schema_migrations_table_name)
+
+        migrated = select_values("SELECT version FROM #{sm_table}").map { |v| v.to_i }
+        paths = migrations_paths.map {|p| "#{p}/[0-9]*_*.rb" }
+        versions = Dir[*paths].map do |filename|
+          filename.split('/').last.split('_').first.to_i
+        end
+
+        unless migrated.include?(version)
+          execute "INSERT INTO #{sm_table} (version) VALUES ('#{version}')"
+        end
+
+        inserted = Set.new
+        (versions - migrated).each do |v|
+          if inserted.include?(v)
+            raise "Duplicate migration #{v}. Please renumber your migrations to resolve the conflict."
+          elsif v < version
+            execute "INSERT INTO #{sm_table} (version) VALUES ('#{v}')"
+            inserted << v
+          end
+        end
+      end
+
+      def type_to_sql(type, limit = nil, precision = nil, scale = nil) #:nodoc:
+        if native = native_database_types[type.to_sym]
+          column_type_sql = (native.is_a?(Hash) ? native[:name] : native).dup
+
+          if type == :decimal # ignore limit, use precision and scale
+            scale ||= native[:scale]
+
+            if precision ||= native[:precision]
+              if scale
+                column_type_sql << "(#{precision},#{scale})"
+              else
+                column_type_sql << "(#{precision})"
+              end
+            elsif scale
+              raise ArgumentError, "Error adding decimal column: precision cannot be empty if scale is specified"
+            end
+
+          elsif (type != :primary_key) && (limit ||= native.is_a?(Hash) && native[:limit])
+            column_type_sql << "(#{limit})"
+          end
+
+          column_type_sql
+        else
+          type.to_s
+        end
+      end
+
+      # Given a set of columns and an ORDER BY clause, returns the columns for a SELECT DISTINCT.
+      # Both PostgreSQL and Oracle overrides this for custom DISTINCT syntax - they
+      # require the order columns appear in the SELECT.
+      #
+      #   columns_for_distinct("posts.id", ["posts.created_at desc"])
+      def columns_for_distinct(columns, orders) #:nodoc:
+        columns
+      end
+
+      # Adds timestamps (+created_at+ and +updated_at+) columns to the named table.
+      #
+      #   add_timestamps(:suppliers)
+      #
+      def add_timestamps(table_name)
+        add_column table_name, :created_at, :datetime
+        add_column table_name, :updated_at, :datetime
+      end
+
+      # Removes the timestamp columns (+created_at+ and +updated_at+) from the table definition.
+      #
+      #  remove_timestamps(:suppliers)
+      #
+      def remove_timestamps(table_name)
+        remove_column table_name, :updated_at
+        remove_column table_name, :created_at
+      end
+
+      def update_table_definition(table_name, base) #:nodoc:
+        Table.new(table_name, base)
+      end
+
+      def add_index_options(table_name, column_name, options = {}) #:nodoc:
+        column_names = Array(column_name)
+        index_name   = index_name(table_name, column: column_names)
+
+        options.assert_valid_keys(:unique, :order, :name, :where, :length, :internal, :using, :algorithm, :type)
+
+        index_type = options[:unique] ? "UNIQUE" : ""
+        index_type = options[:type].to_s if options.key?(:type)
+        index_name = options[:name].to_s if options.key?(:name)
+        max_index_length = options.fetch(:internal, false) ? index_name_length : allowed_index_name_length
+
+        if options.key?(:algorithm)
+          algorithm = index_algorithms.fetch(options[:algorithm]) {
+            raise ArgumentError.new("Algorithm must be one of the following: #{index_algorithms.keys.map(&:inspect).join(', ')}")
+          }
+        end
+
+        using = "USING #{options[:using]}" if options[:using].present?
+
+        if supports_partial_index?
+          index_options = options[:where] ? " WHERE #{options[:where]}" : ""
+        end
+
+        if index_name.length > max_index_length
+          raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{max_index_length} characters"
+        end
+        if table_exists?(table_name) && index_name_exists?(table_name, index_name, false)
+          raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' already exists"
+        end
+        index_columns = quoted_columns_for_index(column_names, options).join(", ")
+
+        [index_name, index_type, index_columns, index_options, algorithm, using]
+      end
+
+      protected
+        def add_index_sort_order(option_strings, column_names, options = {})
+          if options.is_a?(Hash) && order = options[:order]
+            case order
+            when Hash
+              column_names.each {|name| option_strings[name] += " #{order[name].upcase}" if order.has_key?(name)}
+            when String
+              column_names.each {|name| option_strings[name] += " #{order.upcase}"}
+            end
+          end
+
+          return option_strings
+        end
+
+        # Overridden by the MySQL adapter for supporting index lengths
+        def quoted_columns_for_index(column_names, options = {})
+          option_strings = Hash[column_names.map {|name| [name, '']}]
+
+          # add index sort order if supported
+          if supports_index_sort_order?
+            option_strings = add_index_sort_order(option_strings, column_names, options)
+          end
+
+          column_names.map {|name| quote_column_name(name) + option_strings[name]}
+        end
+
+        def options_include_default?(options)
+          options.include?(:default) && !(options[:null] == false && options[:default].nil?)
+        end
+
+        def index_name_for_remove(table_name, options = {})
+          index_name = index_name(table_name, options)
+
+          unless index_name_exists?(table_name, index_name, true)
+            if options.is_a?(Hash) && options.has_key?(:name)
+              options_without_column = options.dup
+              options_without_column.delete :column
+              index_name_without_column = index_name(table_name, options_without_column)
+
+              return index_name_without_column if index_name_exists?(table_name, index_name_without_column, false)
+            end
+
+            raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' does not exist"
+          end
+
+          index_name
+        end
+
+        def rename_table_indexes(table_name, new_name)
+          indexes(new_name).each do |index|
+            generated_index_name = index_name(table_name, column: index.columns)
+            if generated_index_name == index.name
+              rename_index new_name, generated_index_name, index_name(new_name, column: index.columns)
+            end
+          end
+        end
+
+        def rename_column_indexes(table_name, column_name, new_column_name)
+          column_name, new_column_name = column_name.to_s, new_column_name.to_s
+          indexes(table_name).each do |index|
+            next unless index.columns.include?(new_column_name)
+            old_columns = index.columns.dup
+            old_columns[old_columns.index(new_column_name)] = column_name
+            generated_index_name = index_name(table_name, column: old_columns)
+            if generated_index_name == index.name
+              rename_index table_name, generated_index_name, index_name(table_name, column: index.columns)
+            end
+          end
+        end
+
+      private
+      def create_table_definition(name, temporary, options, as = nil)
+        TableDefinition.new native_database_types, name, temporary, options, as
+      end
+
+      def create_alter_table(name)
+        AlterTable.new create_table_definition(name, false, {})
+      end
+
+      def foreign_key_name(table_name, options) # :nodoc:
+        options.fetch(:name) do
+          "fk_rails_#{SecureRandom.hex(5)}"
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
new file mode 100644
index 0000000000..4a7f2aaca8
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
@@ -0,0 +1,197 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class TransactionState
+      attr_reader :parent
+
+      VALID_STATES = Set.new([:committed, :rolledback, nil])
+
+      def initialize(state = nil)
+        @state = state
+        @parent = nil
+      end
+
+      def finalized?
+        @state
+      end
+
+      def committed?
+        @state == :committed
+      end
+
+      def rolledback?
+        @state == :rolledback
+      end
+
+      def set_state(state)
+        if !VALID_STATES.include?(state)
+          raise ArgumentError, "Invalid transaction state: #{state}"
+        end
+        @state = state
+      end
+    end
+
+    class NullTransaction #:nodoc:
+      def initialize; end
+      def closed?; true; end
+      def open?; false; end
+      def joinable?; false; end
+      def add_record(record); end
+    end
+
+    class Transaction #:nodoc:
+
+      attr_reader :connection, :state, :records, :savepoint_name
+      attr_writer :joinable
+
+      def initialize(connection, options)
+        @connection = connection
+        @state = TransactionState.new
+        @records = []
+        @joinable = options.fetch(:joinable, true)
+      end
+
+      def add_record(record)
+        if record.has_transactional_callbacks?
+          records << record
+        else
+          record.set_transaction_state(@state)
+        end
+      end
+
+      def rollback
+        @state.set_state(:rolledback)
+      end
+
+      def rollback_records
+        records.uniq.each do |record|
+          begin
+            record.rolledback! full_rollback?
+          rescue => e
+            record.logger.error(e) if record.respond_to?(:logger) && record.logger
+          end
+        end
+      end
+
+      def commit
+        @state.set_state(:committed)
+      end
+
+      def commit_records
+        records.uniq.each do |record|
+          begin
+            record.committed!
+          rescue => e
+            record.logger.error(e) if record.respond_to?(:logger) && record.logger
+          end
+        end
+      end
+
+      def full_rollback?; true; end
+      def joinable?; @joinable; end
+      def closed?; false; end
+      def open?; !closed?; end
+    end
+
+    class SavepointTransaction < Transaction
+
+      def initialize(connection, savepoint_name, options)
+        super(connection, options)
+        if options[:isolation]
+          raise ActiveRecord::TransactionIsolationError, "cannot set transaction isolation in a nested transaction"
+        end
+        connection.create_savepoint(@savepoint_name = savepoint_name)
+      end
+
+      def rollback
+        super
+        connection.rollback_to_savepoint(savepoint_name)
+        rollback_records
+      end
+
+      def commit
+        super
+        connection.release_savepoint(savepoint_name)
+      end
+
+      def full_rollback?; false; end
+    end
+
+    class RealTransaction < Transaction
+
+      def initialize(connection, options)
+        super
+        if options[:isolation]
+          connection.begin_isolated_db_transaction(options[:isolation])
+        else
+          connection.begin_db_transaction
+        end
+      end
+
+      def rollback
+        super
+        connection.rollback_db_transaction
+        rollback_records
+      end
+
+      def commit
+        super
+        connection.commit_db_transaction
+        commit_records
+      end
+    end
+
+    class TransactionManager #:nodoc:
+      def initialize(connection)
+        @stack = []
+        @connection = connection
+      end
+
+      def begin_transaction(options = {})
+        transaction =
+          if @stack.empty?
+            RealTransaction.new(@connection, options)
+          else
+            SavepointTransaction.new(@connection, "active_record_#{@stack.size}", options)
+          end
+        @stack.push(transaction)
+        transaction
+      end
+
+      def commit_transaction
+        @stack.pop.commit
+      end
+
+      def rollback_transaction
+        @stack.pop.rollback
+      end
+
+      def within_new_transaction(options = {})
+        transaction = begin_transaction options
+        yield
+      rescue Exception => error
+        transaction.rollback if transaction
+        raise
+      ensure
+        begin
+          transaction.commit unless error
+        rescue Exception
+          transaction.rollback
+          raise
+        ensure
+          @stack.pop if transaction
+        end
+      end
+
+      def open_transactions
+        @stack.size
+      end
+
+      def current_transaction
+        @stack.last || NULL_TRANSACTION
+      end
+
+      private
+        NULL_TRANSACTION = NullTransaction.new
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
new file mode 100644
index 0000000000..a1b6671664
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -0,0 +1,479 @@
+require 'date'
+require 'bigdecimal'
+require 'bigdecimal/util'
+require 'active_record/type'
+require 'active_support/core_ext/benchmark'
+require 'active_record/connection_adapters/schema_cache'
+require 'active_record/connection_adapters/abstract/schema_dumper'
+require 'active_record/connection_adapters/abstract/schema_creation'
+require 'monitor'
+require 'arel/collectors/bind'
+require 'arel/collectors/sql_string'
+
+module ActiveRecord
+  module ConnectionAdapters # :nodoc:
+    extend ActiveSupport::Autoload
+
+    autoload_at 'active_record/connection_adapters/column' do
+      autoload :Column
+      autoload :NullColumn
+    end
+    autoload :ConnectionSpecification
+
+    autoload_at 'active_record/connection_adapters/abstract/schema_definitions' do
+      autoload :IndexDefinition
+      autoload :ColumnDefinition
+      autoload :ChangeColumnDefinition
+      autoload :TableDefinition
+      autoload :Table
+      autoload :AlterTable
+    end
+
+    autoload_at 'active_record/connection_adapters/abstract/connection_pool' do
+      autoload :ConnectionHandler
+      autoload :ConnectionManagement
+    end
+
+    autoload_under 'abstract' do
+      autoload :SchemaStatements
+      autoload :DatabaseStatements
+      autoload :DatabaseLimits
+      autoload :Quoting
+      autoload :ConnectionPool
+      autoload :QueryCache
+      autoload :Savepoints
+    end
+
+    autoload_at 'active_record/connection_adapters/abstract/transaction' do
+      autoload :TransactionManager
+      autoload :NullTransaction
+      autoload :RealTransaction
+      autoload :SavepointTransaction
+      autoload :TransactionState
+    end
+
+    # Active Record supports multiple database systems. AbstractAdapter and
+    # related classes form the abstraction layer which makes this possible.
+    # An AbstractAdapter represents a connection to a database, and provides an
+    # abstract interface for database-specific functionality such as establishing
+    # a connection, escaping values, building the right SQL fragments for ':offset'
+    # and ':limit' options, etc.
+    #
+    # All the concrete database adapters follow the interface laid down in this class.
+    # ActiveRecord::Base.connection returns an AbstractAdapter object, which
+    # you can use.
+    #
+    # Most of the methods in the adapter are useful during migrations. Most
+    # notably, the instance methods provided by SchemaStatement are very useful.
+    class AbstractAdapter
+      include Quoting, DatabaseStatements, SchemaStatements
+      include DatabaseLimits
+      include QueryCache
+      include ActiveSupport::Callbacks
+      include MonitorMixin
+      include ColumnDumper
+
+      SIMPLE_INT = /\A\d+\z/
+
+      define_callbacks :checkout, :checkin
+
+      attr_accessor :visitor, :pool
+      attr_reader :schema_cache, :owner, :logger
+      alias :in_use? :owner
+
+      def self.type_cast_config_to_integer(config)
+        if config =~ SIMPLE_INT
+          config.to_i
+        else
+          config
+        end
+      end
+
+      def self.type_cast_config_to_boolean(config)
+        if config == "false"
+          false
+        else
+          config
+        end
+      end
+
+      attr_reader :prepared_statements
+
+      def initialize(connection, logger = nil, pool = nil) #:nodoc:
+        super()
+
+        @connection          = connection
+        @owner               = nil
+        @instrumenter        = ActiveSupport::Notifications.instrumenter
+        @logger              = logger
+        @pool                = pool
+        @schema_cache        = SchemaCache.new self
+        @visitor             = nil
+        @prepared_statements = false
+      end
+
+      class BindCollector < Arel::Collectors::Bind
+        def compile(bvs, conn)
+          super(bvs.map { |bv| conn.quote(*bv.reverse) })
+        end
+      end
+
+      class SQLString < Arel::Collectors::SQLString
+        def compile(bvs, conn)
+          super(bvs)
+        end
+      end
+
+      def collector
+        if prepared_statements
+          SQLString.new
+        else
+          BindCollector.new
+        end
+      end
+
+      def valid_type?(type)
+        true
+      end
+
+      def schema_creation
+        SchemaCreation.new self
+      end
+
+      def lease
+        synchronize do
+          unless in_use?
+            @owner = Thread.current
+          end
+        end
+      end
+
+      def schema_cache=(cache)
+        cache.connection = self
+        @schema_cache = cache
+      end
+
+      def expire
+        @owner = nil
+      end
+
+      def unprepared_statement
+        old_prepared_statements, @prepared_statements = @prepared_statements, false
+        yield
+      ensure
+        @prepared_statements = old_prepared_statements
+      end
+
+      # Returns the human-readable name of the adapter. Use mixed case - one
+      # can always use downcase if needed.
+      def adapter_name
+        'Abstract'
+      end
+
+      # Does this adapter support migrations?
+      def supports_migrations?
+        false
+      end
+
+      # Can this adapter determine the primary key for tables not attached
+      # to an Active Record class, such as join tables?
+      def supports_primary_key?
+        false
+      end
+
+      # Does this adapter support DDL rollbacks in transactions? That is, would
+      # CREATE TABLE or ALTER TABLE get rolled back by a transaction?
+      def supports_ddl_transactions?
+        false
+      end
+
+      def supports_bulk_alter?
+        false
+      end
+
+      # Does this adapter support savepoints?
+      def supports_savepoints?
+        false
+      end
+
+      # Should primary key values be selected from their corresponding
+      # sequence before the insert statement? If true, next_sequence_value
+      # is called before each insert to set the record's primary key.
+      def prefetch_primary_key?(table_name = nil)
+        false
+      end
+
+      # Does this adapter support index sort order?
+      def supports_index_sort_order?
+        false
+      end
+
+      # Does this adapter support partial indices?
+      def supports_partial_index?
+        false
+      end
+
+      # Does this adapter support explain?
+      def supports_explain?
+        false
+      end
+
+      # Does this adapter support setting the isolation level for a transaction?
+      def supports_transaction_isolation?
+        false
+      end
+
+      # Does this adapter support database extensions?
+      def supports_extensions?
+        false
+      end
+
+      # Does this adapter support creating indexes in the same statement as
+      # creating the table?
+      def supports_indexes_in_create?
+        false
+      end
+
+      # Does this adapter support creating foreign key constraints?
+      def supports_foreign_keys?
+        false
+      end
+
+      # This is meant to be implemented by the adapters that support extensions
+      def disable_extension(name)
+      end
+
+      # This is meant to be implemented by the adapters that support extensions
+      def enable_extension(name)
+      end
+
+      # A list of extensions, to be filled in by adapters that support them.
+      def extensions
+        []
+      end
+
+      # A list of index algorithms, to be filled by adapters that support them.
+      def index_algorithms
+        {}
+      end
+
+      # QUOTING ==================================================
+
+      # Returns a bind substitution value given a bind +index+ and +column+
+      # NOTE: The column param is currently being used by the sqlserver-adapter
+      def substitute_at(column, index)
+        Arel::Nodes::BindParam.new '?'
+      end
+
+      # REFERENTIAL INTEGRITY ====================================
+
+      # Override to turn off referential integrity while executing <tt>&block</tt>.
+      def disable_referential_integrity
+        yield
+      end
+
+      # CONNECTION MANAGEMENT ====================================
+
+      # Checks whether the connection to the database is still active. This includes
+      # checking whether the database is actually capable of responding, i.e. whether
+      # the connection isn't stale.
+      def active?
+      end
+
+      # Disconnects from the database if already connected, and establishes a
+      # new connection with the database. Implementors should call super if they
+      # override the default implementation.
+      def reconnect!
+        clear_cache!
+        reset_transaction
+      end
+
+      # Disconnects from the database if already connected. Otherwise, this
+      # method does nothing.
+      def disconnect!
+        clear_cache!
+        reset_transaction
+      end
+
+      # Reset the state of this connection, directing the DBMS to clear
+      # transactions and other connection-related server-side state. Usually a
+      # database-dependent operation.
+      #
+      # The default implementation does nothing; the implementation should be
+      # overridden by concrete adapters.
+      def reset!
+        # this should be overridden by concrete adapters
+      end
+
+      ###
+      # Clear any caching the database adapter may be doing, for example
+      # clearing the prepared statement cache. This is database specific.
+      def clear_cache!
+        # this should be overridden by concrete adapters
+      end
+
+      # Returns true if its required to reload the connection between requests for development mode.
+      def requires_reloading?
+        false
+      end
+
+      # Checks whether the connection to the database is still active (i.e. not stale).
+      # This is done under the hood by calling <tt>active?</tt>. If the connection
+      # is no longer active, then this method will reconnect to the database.
+      def verify!(*ignored)
+        reconnect! unless active?
+      end
+
+      # Provides access to the underlying database driver for this adapter. For
+      # example, this method returns a Mysql object in case of MysqlAdapter,
+      # and a PGconn object in case of PostgreSQLAdapter.
+      #
+      # This is useful for when you need to call a proprietary method such as
+      # PostgreSQL's lo_* methods.
+      def raw_connection
+        @connection
+      end
+
+      def create_savepoint(name = nil)
+      end
+
+      def rollback_to_savepoint(name = nil)
+      end
+
+      def release_savepoint(name = nil)
+      end
+
+      def case_sensitive_modifier(node, table_attribute)
+        node
+      end
+
+      def case_sensitive_comparison(table, attribute, column, value)
+        table_attr = table[attribute]
+        value = case_sensitive_modifier(value, table_attr) unless value.nil?
+        table_attr.eq(value)
+      end
+
+      def case_insensitive_comparison(table, attribute, column, value)
+        table[attribute].lower.eq(table.lower(value))
+      end
+
+      def current_savepoint_name
+        current_transaction.savepoint_name
+      end
+
+      # Check the connection back in to the connection pool
+      def close
+        pool.checkin self
+      end
+
+      def type_map # :nodoc:
+        @type_map ||= Type::TypeMap.new.tap do |mapping|
+          initialize_type_map(mapping)
+        end
+      end
+
+      def new_column(name, default, cast_type, sql_type = nil, null = true)
+        Column.new(name, default, cast_type, sql_type, null)
+      end
+
+      def lookup_cast_type(sql_type) # :nodoc:
+        type_map.lookup(sql_type)
+      end
+
+      protected
+
+      def initialize_type_map(m) # :nodoc:
+        register_class_with_limit m, %r(boolean)i,   Type::Boolean
+        register_class_with_limit m, %r(char)i,      Type::String
+        register_class_with_limit m, %r(binary)i,    Type::Binary
+        register_class_with_limit m, %r(text)i,      Type::Text
+        register_class_with_limit m, %r(date)i,      Type::Date
+        register_class_with_limit m, %r(time)i,      Type::Time
+        register_class_with_limit m, %r(datetime)i,  Type::DateTime
+        register_class_with_limit m, %r(float)i,     Type::Float
+        register_class_with_limit m, %r(int)i,       Type::Integer
+
+        m.alias_type %r(blob)i,      'binary'
+        m.alias_type %r(clob)i,      'text'
+        m.alias_type %r(timestamp)i, 'datetime'
+        m.alias_type %r(numeric)i,   'decimal'
+        m.alias_type %r(number)i,    'decimal'
+        m.alias_type %r(double)i,    'float'
+
+        m.register_type(%r(decimal)i) do |sql_type|
+          scale = extract_scale(sql_type)
+          precision = extract_precision(sql_type)
+
+          if scale == 0
+            # FIXME: Remove this class as well
+            Type::DecimalWithoutScale.new(precision: precision)
+          else
+            Type::Decimal.new(precision: precision, scale: scale)
+          end
+        end
+      end
+
+      def reload_type_map # :nodoc:
+        type_map.clear
+        initialize_type_map(type_map)
+      end
+
+      def register_class_with_limit(mapping, key, klass) # :nodoc:
+        mapping.register_type(key) do |*args|
+          limit = extract_limit(args.last)
+          klass.new(limit: limit)
+        end
+      end
+
+      def extract_scale(sql_type) # :nodoc:
+        case sql_type
+          when /\((\d+)\)/ then 0
+          when /\((\d+)(,(\d+))\)/ then $3.to_i
+        end
+      end
+
+      def extract_precision(sql_type) # :nodoc:
+        $1.to_i if sql_type =~ /\((\d+)(,\d+)?\)/
+      end
+
+      def extract_limit(sql_type) # :nodoc:
+        $1.to_i if sql_type =~ /\((.*)\)/
+      end
+
+      def translate_exception_class(e, sql)
+        message = "#{e.class.name}: #{e.message}: #{sql}"
+        @logger.error message if @logger
+        exception = translate_exception(e, message)
+        exception.set_backtrace e.backtrace
+        exception
+      end
+
+      def log(sql, name = "SQL", binds = [], statement_name = nil)
+        @instrumenter.instrument(
+          "sql.active_record",
+          :sql            => sql,
+          :name           => name,
+          :connection_id  => object_id,
+          :statement_name => statement_name,
+          :binds          => binds) { yield }
+      rescue => e
+        raise translate_exception_class(e, sql)
+      end
+
+      def translate_exception(exception, message)
+        # override in derived class
+        ActiveRecord::StatementInvalid.new(message, exception)
+      end
+
+      def without_prepared_statement?(binds)
+        !prepared_statements || binds.empty?
+      end
+
+      def column_for(table_name, column_name) # :nodoc:
+        column_name = column_name.to_s
+        columns(table_name).detect { |c| c.name == column_name } ||
+          raise(ActiveRecordError, "No such column: #{table_name}.#{column_name}")
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
new file mode 100644
index 0000000000..e5417a9556
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -0,0 +1,841 @@
+require 'arel/visitors/bind_visitor'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class AbstractMysqlAdapter < AbstractAdapter
+      include Savepoints
+
+      class SchemaCreation < AbstractAdapter::SchemaCreation
+        def visit_AddColumn(o)
+          add_column_position!(super, column_options(o))
+        end
+
+        private
+
+        def visit_DropForeignKey(name)
+          "DROP FOREIGN KEY #{name}"
+        end
+
+        def visit_TableDefinition(o)
+          name = o.name
+          create_sql = "CREATE#{' TEMPORARY' if o.temporary} TABLE #{quote_table_name(name)} "
+
+          statements = o.columns.map { |c| accept c }
+          statements.concat(o.indexes.map { |column_name, options| index_in_create(name, column_name, options) })
+
+          create_sql << "(#{statements.join(', ')}) " if statements.present?
+          create_sql << "#{o.options}"
+          create_sql << " AS #{@conn.to_sql(o.as)}" if o.as
+          create_sql
+        end
+
+        def visit_ChangeColumnDefinition(o)
+          column = o.column
+          options = o.options
+          sql_type = type_to_sql(o.type, options[:limit], options[:precision], options[:scale])
+          change_column_sql = "CHANGE #{quote_column_name(column.name)} #{quote_column_name(options[:name])} #{sql_type}"
+          add_column_options!(change_column_sql, options.merge(column: column))
+          add_column_position!(change_column_sql, options)
+        end
+
+        def add_column_position!(sql, options)
+          if options[:first]
+            sql << " FIRST"
+          elsif options[:after]
+            sql << " AFTER #{quote_column_name(options[:after])}"
+          end
+          sql
+        end
+
+        def index_in_create(table_name, column_name, options)
+          index_name, index_type, index_columns, index_options, index_algorithm, index_using = @conn.add_index_options(table_name, column_name, options)
+          "#{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns})#{index_options} #{index_algorithm}"
+        end
+      end
+
+      def schema_creation
+        SchemaCreation.new self
+      end
+
+      class Column < ConnectionAdapters::Column # :nodoc:
+        attr_reader :collation, :strict, :extra
+
+        def initialize(name, default, cast_type, sql_type = nil, null = true, collation = nil, strict = false, extra = "")
+          @strict    = strict
+          @collation = collation
+          @extra     = extra
+          super(name, default, cast_type, sql_type, null)
+          assert_valid_default(default)
+          extract_default
+        end
+
+        def extract_default
+          if blob_or_text_column?
+            @default = null || strict ? nil : ''
+          elsif missing_default_forged_as_empty_string?(@default)
+            @default = nil
+          end
+        end
+
+        def has_default?
+          return false if blob_or_text_column? # MySQL forbids defaults on blob and text columns
+          super
+        end
+
+        def blob_or_text_column?
+          sql_type =~ /blob/i || type == :text
+        end
+
+        def case_sensitive?
+          collation && !collation.match(/_ci$/)
+        end
+
+        private
+
+        # MySQL misreports NOT NULL column default when none is given.
+        # We can't detect this for columns which may have a legitimate ''
+        # default (string) but we can for others (integer, datetime, boolean,
+        # and the rest).
+        #
+        # Test whether the column has default '', is not null, and is not
+        # a type allowing default ''.
+        def missing_default_forged_as_empty_string?(default)
+          type != :string && !null && default == ''
+        end
+
+        def assert_valid_default(default)
+          if blob_or_text_column? && default.present?
+            raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
+          end
+        end
+      end
+
+      ##
+      # :singleton-method:
+      # By default, the MysqlAdapter will consider all columns of type <tt>tinyint(1)</tt>
+      # as boolean. If you wish to disable this emulation (which was the default
+      # behavior in versions 0.13.1 and earlier) you can add the following line
+      # to your application.rb file:
+      #
+      #   ActiveRecord::ConnectionAdapters::Mysql[2]Adapter.emulate_booleans = false
+      class_attribute :emulate_booleans
+      self.emulate_booleans = true
+
+      LOST_CONNECTION_ERROR_MESSAGES = [
+        "Server shutdown in progress",
+        "Broken pipe",
+        "Lost connection to MySQL server during query",
+        "MySQL server has gone away" ]
+
+      QUOTED_TRUE, QUOTED_FALSE = '1', '0'
+
+      NATIVE_DATABASE_TYPES = {
+        :primary_key => "int(11) auto_increment PRIMARY KEY",
+        :string      => { :name => "varchar", :limit => 255 },
+        :text        => { :name => "text" },
+        :integer     => { :name => "int", :limit => 4 },
+        :float       => { :name => "float" },
+        :decimal     => { :name => "decimal" },
+        :datetime    => { :name => "datetime" },
+        :time        => { :name => "time" },
+        :date        => { :name => "date" },
+        :binary      => { :name => "blob" },
+        :boolean     => { :name => "tinyint", :limit => 1 }
+      }
+
+      INDEX_TYPES  = [:fulltext, :spatial]
+      INDEX_USINGS = [:btree, :hash]
+
+      # FIXME: Make the first parameter more similar for the two adapters
+      def initialize(connection, logger, connection_options, config)
+        super(connection, logger)
+        @connection_options, @config = connection_options, config
+        @quoted_column_names, @quoted_table_names = {}, {}
+
+        @visitor = Arel::Visitors::MySQL.new self
+
+        if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
+          @prepared_statements = true
+        else
+          @prepared_statements = false
+        end
+      end
+
+      def adapter_name #:nodoc:
+        self.class::ADAPTER_NAME
+      end
+
+      # Returns true, since this connection adapter supports migrations.
+      def supports_migrations?
+        true
+      end
+
+      def supports_primary_key?
+        true
+      end
+
+      def supports_bulk_alter? #:nodoc:
+        true
+      end
+
+      # Technically MySQL allows to create indexes with the sort order syntax
+      # but at the moment (5.5) it doesn't yet implement them
+      def supports_index_sort_order?
+        true
+      end
+
+      # MySQL 4 technically support transaction isolation, but it is affected by a bug
+      # where the transaction level gets persisted for the whole session:
+      #
+      # http://bugs.mysql.com/bug.php?id=39170
+      def supports_transaction_isolation?
+        version[0] >= 5
+      end
+
+      def supports_indexes_in_create?
+        true
+      end
+
+      def supports_foreign_keys?
+        true
+      end
+
+      def native_database_types
+        NATIVE_DATABASE_TYPES
+      end
+
+      def index_algorithms
+        { default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
+      end
+
+      # HELPER METHODS ===========================================
+
+      # The two drivers have slightly different ways of yielding hashes of results, so
+      # this method must be implemented to provide a uniform interface.
+      def each_hash(result) # :nodoc:
+        raise NotImplementedError
+      end
+
+      def new_column(field, default, cast_type, sql_type = nil, null = true, collation = "", extra = "") # :nodoc:
+        Column.new(field, default, cast_type, sql_type, null, collation, strict_mode?, extra)
+      end
+
+      # Must return the MySQL error number from the exception, if the exception has an
+      # error number.
+      def error_number(exception) # :nodoc:
+        raise NotImplementedError
+      end
+
+      # QUOTING ==================================================
+
+      def _quote(value) # :nodoc:
+        if value.is_a?(Type::Binary::Data)
+          "x'#{value.hex}'"
+        else
+          super
+        end
+      end
+
+      def quote_column_name(name) #:nodoc:
+        @quoted_column_names[name] ||= "`#{name.to_s.gsub('`', '``')}`"
+      end
+
+      def quote_table_name(name) #:nodoc:
+        @quoted_table_names[name] ||= quote_column_name(name).gsub('.', '`.`')
+      end
+
+      def quoted_true
+        QUOTED_TRUE
+      end
+
+      def unquoted_true
+        1
+      end
+
+      def quoted_false
+        QUOTED_FALSE
+      end
+
+      def unquoted_false
+        0
+      end
+
+      # REFERENTIAL INTEGRITY ====================================
+
+      def disable_referential_integrity #:nodoc:
+        old = select_value("SELECT @@FOREIGN_KEY_CHECKS")
+
+        begin
+          update("SET FOREIGN_KEY_CHECKS = 0")
+          yield
+        ensure
+          update("SET FOREIGN_KEY_CHECKS = #{old}")
+        end
+      end
+
+      # DATABASE STATEMENTS ======================================
+
+      def clear_cache!
+        super
+        reload_type_map
+      end
+
+      # Executes the SQL statement in the context of this connection.
+      def execute(sql, name = nil)
+        log(sql, name) { @connection.query(sql) }
+      end
+
+      # MysqlAdapter has to free a result after using it, so we use this method to write
+      # stuff in an abstract way without concerning ourselves about whether it needs to be
+      # explicitly freed or not.
+      def execute_and_free(sql, name = nil) #:nodoc:
+        yield execute(sql, name)
+      end
+
+      def update_sql(sql, name = nil) #:nodoc:
+        super
+        @connection.affected_rows
+      end
+
+      def begin_db_transaction
+        execute "BEGIN"
+      end
+
+      def begin_isolated_db_transaction(isolation)
+        execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
+        begin_db_transaction
+      end
+
+      def commit_db_transaction #:nodoc:
+        execute "COMMIT"
+      end
+
+      def rollback_db_transaction #:nodoc:
+        execute "ROLLBACK"
+      end
+
+      # In the simple case, MySQL allows us to place JOINs directly into the UPDATE
+      # query. However, this does not allow for LIMIT, OFFSET and ORDER. To support
+      # these, we must use a subquery.
+      def join_to_update(update, select) #:nodoc:
+        if select.limit || select.offset || select.orders.any?
+          super
+        else
+          update.table select.source
+          update.wheres = select.constraints
+        end
+      end
+
+      def empty_insert_statement_value
+        "VALUES ()"
+      end
+
+      # SCHEMA STATEMENTS ========================================
+
+      # Drops the database specified on the +name+ attribute
+      # and creates it again using the provided +options+.
+      def recreate_database(name, options = {})
+        drop_database(name)
+        sql = create_database(name, options)
+        reconnect!
+        sql
+      end
+
+      # Create a new MySQL database with optional <tt>:charset</tt> and <tt>:collation</tt>.
+      # Charset defaults to utf8.
+      #
+      # Example:
+      #   create_database 'charset_test', charset: 'latin1', collation: 'latin1_bin'
+      #   create_database 'matt_development'
+      #   create_database 'matt_development', charset: :big5
+      def create_database(name, options = {})
+        if options[:collation]
+          execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}` COLLATE `#{options[:collation]}`"
+        else
+          execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}`"
+        end
+      end
+
+      # Drops a MySQL database.
+      #
+      # Example:
+      #   drop_database('sebastian_development')
+      def drop_database(name) #:nodoc:
+        execute "DROP DATABASE IF EXISTS `#{name}`"
+      end
+
+      def current_database
+        select_value 'SELECT DATABASE() as db'
+      end
+
+      # Returns the database character set.
+      def charset
+        show_variable 'character_set_database'
+      end
+
+      # Returns the database collation strategy.
+      def collation
+        show_variable 'collation_database'
+      end
+
+      def tables(name = nil, database = nil, like = nil) #:nodoc:
+        sql = "SHOW TABLES "
+        sql << "IN #{quote_table_name(database)} " if database
+        sql << "LIKE #{quote(like)}" if like
+
+        execute_and_free(sql, 'SCHEMA') do |result|
+          result.collect { |field| field.first }
+        end
+      end
+
+      def table_exists?(name)
+        return false unless name.present?
+        return true if tables(nil, nil, name).any?
+
+        name          = name.to_s
+        schema, table = name.split('.', 2)
+
+        unless table # A table was provided without a schema
+          table  = schema
+          schema = nil
+        end
+
+        tables(nil, schema, table).any?
+      end
+
+      # Returns an array of indexes for the given table.
+      def indexes(table_name, name = nil) #:nodoc:
+        indexes = []
+        current_index = nil
+        execute_and_free("SHOW KEYS FROM #{quote_table_name(table_name)}", 'SCHEMA') do |result|
+          each_hash(result) do |row|
+            if current_index != row[:Key_name]
+              next if row[:Key_name] == 'PRIMARY' # skip the primary key
+              current_index = row[:Key_name]
+
+              mysql_index_type = row[:Index_type].downcase.to_sym
+              index_type  = INDEX_TYPES.include?(mysql_index_type)  ? mysql_index_type : nil
+              index_using = INDEX_USINGS.include?(mysql_index_type) ? mysql_index_type : nil
+              indexes << IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique].to_i == 0, [], [], nil, nil, index_type, index_using)
+            end
+
+            indexes.last.columns << row[:Column_name]
+            indexes.last.lengths << row[:Sub_part]
+          end
+        end
+
+        indexes
+      end
+
+      # Returns an array of +Column+ objects for the table specified by +table_name+.
+      def columns(table_name)#:nodoc:
+        sql = "SHOW FULL FIELDS FROM #{quote_table_name(table_name)}"
+        execute_and_free(sql, 'SCHEMA') do |result|
+          each_hash(result).map do |field|
+            field_name = set_field_encoding(field[:Field])
+            sql_type = field[:Type]
+            cast_type = lookup_cast_type(sql_type)
+            new_column(field_name, field[:Default], cast_type, sql_type, field[:Null] == "YES", field[:Collation], field[:Extra])
+          end
+        end
+      end
+
+      def create_table(table_name, options = {}) #:nodoc:
+        super(table_name, options.reverse_merge(:options => "ENGINE=InnoDB"))
+      end
+
+      def bulk_change_table(table_name, operations) #:nodoc:
+        sqls = operations.flat_map do |command, args|
+          table, arguments = args.shift, args
+          method = :"#{command}_sql"
+
+          if respond_to?(method, true)
+            send(method, table, *arguments)
+          else
+            raise "Unknown method called : #{method}(#{arguments.inspect})"
+          end
+        end.join(", ")
+
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{sqls}")
+      end
+
+      # Renames a table.
+      #
+      # Example:
+      #   rename_table('octopuses', 'octopi')
+      def rename_table(table_name, new_name)
+        execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
+        rename_table_indexes(table_name, new_name)
+      end
+
+      def drop_table(table_name, options = {})
+        execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE #{quote_table_name(table_name)}"
+      end
+
+      def rename_index(table_name, old_name, new_name)
+        if supports_rename_index?
+          execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"
+        else
+          super
+        end
+      end
+
+      def change_column_default(table_name, column_name, default)
+        column = column_for(table_name, column_name)
+        change_column table_name, column_name, column.sql_type, :default => default
+      end
+
+      def change_column_null(table_name, column_name, null, default = nil)
+        column = column_for(table_name, column_name)
+
+        unless null || default.nil?
+          execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
+        end
+
+        change_column table_name, column_name, column.sql_type, :null => null
+      end
+
+      def change_column(table_name, column_name, type, options = {}) #:nodoc:
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{change_column_sql(table_name, column_name, type, options)}")
+      end
+
+      def rename_column(table_name, column_name, new_column_name) #:nodoc:
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
+        rename_column_indexes(table_name, column_name, new_column_name)
+      end
+
+      def add_index(table_name, column_name, options = {}) #:nodoc:
+        index_name, index_type, index_columns, index_options, index_algorithm, index_using = add_index_options(table_name, column_name, options)
+        execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} ON #{quote_table_name(table_name)} (#{index_columns})#{index_options} #{index_algorithm}"
+      end
+
+      def foreign_keys(table_name)
+        fk_info = select_all <<-SQL.strip_heredoc
+          SELECT fk.referenced_table_name as 'to_table'
+                ,fk.referenced_column_name as 'primary_key'
+                ,fk.column_name as 'column'
+                ,fk.constraint_name as 'name'
+          FROM information_schema.key_column_usage fk
+          WHERE fk.referenced_column_name is not null
+            AND fk.table_schema = '#{@config[:database]}'
+            AND fk.table_name = '#{table_name}'
+        SQL
+
+        create_table_info = select_one("SHOW CREATE TABLE #{quote_table_name(table_name)}")["Create Table"]
+
+        fk_info.map do |row|
+          options = {
+            column: row['column'],
+            name: row['name'],
+            primary_key: row['primary_key']
+          }
+
+          options[:on_update] = extract_foreign_key_action(create_table_info, row['name'], "UPDATE")
+          options[:on_delete] = extract_foreign_key_action(create_table_info, row['name'], "DELETE")
+
+          ForeignKeyDefinition.new(table_name, row['to_table'], options)
+        end
+      end
+
+      # Maps logical Rails types to MySQL-specific data types.
+      def type_to_sql(type, limit = nil, precision = nil, scale = nil)
+        case type.to_s
+        when 'binary'
+          case limit
+          when 0..0xfff;           "varbinary(#{limit})"
+          when nil;                "blob"
+          when 0x1000..0xffffffff; "blob(#{limit})"
+          else raise(ActiveRecordError, "No binary type has character length #{limit}")
+          end
+        when 'integer'
+          case limit
+          when 1; 'tinyint'
+          when 2; 'smallint'
+          when 3; 'mediumint'
+          when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
+          when 5..8; 'bigint'
+          else raise(ActiveRecordError, "No integer type has byte size #{limit}")
+          end
+        when 'text'
+          case limit
+          when 0..0xff;               'tinytext'
+          when nil, 0x100..0xffff;    'text'
+          when 0x10000..0xffffff;     'mediumtext'
+          when 0x1000000..0xffffffff; 'longtext'
+          else raise(ActiveRecordError, "No text type has character length #{limit}")
+          end
+        else
+          super
+        end
+      end
+
+      def add_column_position!(sql, options)
+        if options[:first]
+          sql << " FIRST"
+        elsif options[:after]
+          sql << " AFTER #{quote_column_name(options[:after])}"
+        end
+      end
+
+      # SHOW VARIABLES LIKE 'name'
+      def show_variable(name)
+        variables = select_all("SHOW VARIABLES LIKE '#{name}'", 'SCHEMA')
+        variables.first['Value'] unless variables.empty?
+      end
+
+      # Returns a table's primary key and belonging sequence.
+      def pk_and_sequence_for(table)
+        execute_and_free("SHOW CREATE TABLE #{quote_table_name(table)}", 'SCHEMA') do |result|
+          create_table = each_hash(result).first[:"Create Table"]
+          if create_table.to_s =~ /PRIMARY KEY\s+(?:USING\s+\w+\s+)?\((.+)\)/
+            keys = $1.split(",").map { |key| key.delete('`"') }
+            keys.length == 1 ? [keys.first, nil] : nil
+          else
+            nil
+          end
+        end
+      end
+
+      # Returns just a table's primary key
+      def primary_key(table)
+        pk_and_sequence = pk_and_sequence_for(table)
+        pk_and_sequence && pk_and_sequence.first
+      end
+
+      def case_sensitive_modifier(node, table_attribute)
+        node = Arel::Nodes.build_quoted node, table_attribute
+        Arel::Nodes::Bin.new(node)
+      end
+
+      def case_sensitive_comparison(table, attribute, column, value)
+        if column.case_sensitive?
+          table[attribute].eq(value)
+        else
+          super
+        end
+      end
+
+      def case_insensitive_comparison(table, attribute, column, value)
+        if column.case_sensitive?
+          super
+        else
+          table[attribute].eq(value)
+        end
+      end
+
+      def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
+        where_sql
+      end
+
+      def strict_mode?
+        self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
+      end
+
+      def valid_type?(type)
+        !native_database_types[type].nil?
+      end
+
+      protected
+
+      def initialize_type_map(m) # :nodoc:
+        super
+        m.register_type(%r(enum)i) do |sql_type|
+          limit = sql_type[/^enum\((.+)\)/i, 1]
+            .split(',').map{|enum| enum.strip.length - 2}.max
+          Type::String.new(limit: limit)
+        end
+
+        m.register_type %r(tinytext)i,   Type::Text.new(limit: 255)
+        m.register_type %r(tinyblob)i,   Type::Binary.new(limit: 255)
+        m.register_type %r(mediumtext)i, Type::Text.new(limit: 16777215)
+        m.register_type %r(mediumblob)i, Type::Binary.new(limit: 16777215)
+        m.register_type %r(longtext)i,   Type::Text.new(limit: 2147483647)
+        m.register_type %r(longblob)i,   Type::Binary.new(limit: 2147483647)
+        m.register_type %r(^bigint)i,    Type::Integer.new(limit: 8)
+        m.register_type %r(^int)i,       Type::Integer.new(limit: 4)
+        m.register_type %r(^mediumint)i, Type::Integer.new(limit: 3)
+        m.register_type %r(^smallint)i,  Type::Integer.new(limit: 2)
+        m.register_type %r(^tinyint)i,   Type::Integer.new(limit: 1)
+        m.register_type %r(^float)i,     Type::Float.new(limit: 24)
+        m.register_type %r(^double)i,    Type::Float.new(limit: 53)
+
+        m.alias_type %r(tinyint\(1\))i,  'boolean' if emulate_booleans
+        m.alias_type %r(set)i,           'varchar'
+        m.alias_type %r(year)i,          'integer'
+        m.alias_type %r(bit)i,           'binary'
+      end
+
+      # MySQL is too stupid to create a temporary table for use subquery, so we have
+      # to give it some prompting in the form of a subsubquery. Ugh!
+      def subquery_for(key, select)
+        subsubselect = select.clone
+        subsubselect.projections = [key]
+
+        subselect = Arel::SelectManager.new(select.engine)
+        subselect.project Arel.sql(key.name)
+        subselect.from subsubselect.as('__active_record_temp')
+      end
+
+      def add_index_length(option_strings, column_names, options = {})
+        if options.is_a?(Hash) && length = options[:length]
+          case length
+          when Hash
+            column_names.each {|name| option_strings[name] += "(#{length[name]})" if length.has_key?(name) && length[name].present?}
+          when Fixnum
+            column_names.each {|name| option_strings[name] += "(#{length})"}
+          end
+        end
+
+        return option_strings
+      end
+
+      def quoted_columns_for_index(column_names, options = {})
+        option_strings = Hash[column_names.map {|name| [name, '']}]
+
+        # add index length
+        option_strings = add_index_length(option_strings, column_names, options)
+
+        # add index sort order
+        option_strings = add_index_sort_order(option_strings, column_names, options)
+
+        column_names.map {|name| quote_column_name(name) + option_strings[name]}
+      end
+
+      def translate_exception(exception, message)
+        case error_number(exception)
+        when 1062
+          RecordNotUnique.new(message, exception)
+        when 1452
+          InvalidForeignKey.new(message, exception)
+        else
+          super
+        end
+      end
+
+      def add_column_sql(table_name, column_name, type, options = {})
+        td = create_table_definition table_name, options[:temporary], options[:options]
+        cd = td.new_column_definition(column_name, type, options)
+        schema_creation.visit_AddColumn cd
+      end
+
+      def change_column_sql(table_name, column_name, type, options = {})
+        column = column_for(table_name, column_name)
+
+        unless options_include_default?(options)
+          options[:default] = column.default
+        end
+
+        unless options.has_key?(:null)
+          options[:null] = column.null
+        end
+
+        options[:name] = column.name
+        schema_creation.accept ChangeColumnDefinition.new column, type, options
+      end
+
+      def rename_column_sql(table_name, column_name, new_column_name)
+        column  = column_for(table_name, column_name)
+        options = {
+          name: new_column_name,
+          default: column.default,
+          null: column.null,
+          auto_increment: column.extra == "auto_increment"
+        }
+
+        current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'", 'SCHEMA')["Type"]
+        schema_creation.accept ChangeColumnDefinition.new column, current_type, options
+      end
+
+      def remove_column_sql(table_name, column_name, type = nil, options = {})
+        "DROP #{quote_column_name(column_name)}"
+      end
+
+      def remove_columns_sql(table_name, *column_names)
+        column_names.map {|column_name| remove_column_sql(table_name, column_name) }
+      end
+
+      def add_index_sql(table_name, column_name, options = {})
+        index_name, index_type, index_columns = add_index_options(table_name, column_name, options)
+        "ADD #{index_type} INDEX #{index_name} (#{index_columns})"
+      end
+
+      def remove_index_sql(table_name, options = {})
+        index_name = index_name_for_remove(table_name, options)
+        "DROP INDEX #{index_name}"
+      end
+
+      def add_timestamps_sql(table_name)
+        [add_column_sql(table_name, :created_at, :datetime), add_column_sql(table_name, :updated_at, :datetime)]
+      end
+
+      def remove_timestamps_sql(table_name)
+        [remove_column_sql(table_name, :updated_at), remove_column_sql(table_name, :created_at)]
+      end
+
+      private
+
+      def version
+        @version ||= full_version.scan(/^(\d+)\.(\d+)\.(\d+)/).flatten.map { |v| v.to_i }
+      end
+
+      def mariadb?
+        full_version =~ /mariadb/i
+      end
+
+      def supports_views?
+        version[0] >= 5
+      end
+
+      def supports_rename_index?
+        mariadb? ? false : (version[0] == 5 && version[1] >= 7) || version[0] >= 6
+      end
+
+      def configure_connection
+        variables = @config.fetch(:variables, {}).stringify_keys
+
+        # By default, MySQL 'where id is null' selects the last inserted id.
+        # Turn this off. http://dev.rubyonrails.org/ticket/6778
+        variables['sql_auto_is_null'] = 0
+
+        # Increase timeout so the server doesn't disconnect us.
+        wait_timeout = @config[:wait_timeout]
+        wait_timeout = 2147483 unless wait_timeout.is_a?(Fixnum)
+        variables['wait_timeout'] = self.class.type_cast_config_to_integer(wait_timeout)
+
+        # Make MySQL reject illegal values rather than truncating or blanking them, see
+        # http://dev.mysql.com/doc/refman/5.0/en/server-sql-mode.html#sqlmode_strict_all_tables
+        # If the user has provided another value for sql_mode, don't replace it.
+        unless variables.has_key?('sql_mode')
+          variables['sql_mode'] = strict_mode? ? 'STRICT_ALL_TABLES' : ''
+        end
+
+        # NAMES does not have an equals sign, see
+        # http://dev.mysql.com/doc/refman/5.0/en/set-statement.html#id944430
+        # (trailing comma because variable_assignments will always have content)
+        encoding = "NAMES #{@config[:encoding]}, " if @config[:encoding]
+
+        # Gather up all of the SET variables...
+        variable_assignments = variables.map do |k, v|
+          if v == ':default' || v == :default
+            "@@SESSION.#{k.to_s} = DEFAULT" # Sets the value to the global or compile default
+          elsif !v.nil?
+            "@@SESSION.#{k.to_s} = #{quote(v)}"
+          end
+          # or else nil; compact to clear nils out
+        end.compact.join(', ')
+
+        # ...and send them all in one query
+        @connection.query  "SET #{encoding} #{variable_assignments}"
+      end
+
+      def extract_foreign_key_action(structure, name, action) # :nodoc:
+        if structure =~ /CONSTRAINT #{quote_column_name(name)} FOREIGN KEY .* REFERENCES .* ON #{action} (CASCADE|SET NULL|RESTRICT)/
+          case $1
+          when 'CASCADE'; :cascade
+          when 'SET NULL'; :nullify
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
new file mode 100644
index 0000000000..5f9cc6edd0
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -0,0 +1,62 @@
+require 'set'
+
+module ActiveRecord
+  # :stopdoc:
+  module ConnectionAdapters
+    # An abstract definition of a column in a table.
+    class Column
+      TRUE_VALUES = [true, 1, '1', 't', 'T', 'true', 'TRUE', 'on', 'ON'].to_set
+      FALSE_VALUES = [false, 0, '0', 'f', 'F', 'false', 'FALSE', 'off', 'OFF'].to_set
+
+      module Format
+        ISO_DATE = /\A(\d{4})-(\d\d)-(\d\d)\z/
+        ISO_DATETIME = /\A(\d{4})-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)(\.\d+)?\z/
+      end
+
+      attr_reader :name, :cast_type, :null, :sql_type, :default, :default_function
+
+      delegate :type, :precision, :scale, :limit, :klass, :accessor,
+        :number?, :binary?, :changed?,
+        :type_cast_from_user, :type_cast_from_database, :type_cast_for_database,
+        :type_cast_for_schema,
+        to: :cast_type
+
+      # Instantiates a new column in the table.
+      #
+      # +name+ is the column's name, such as <tt>supplier_id</tt> in <tt>supplier_id int(11)</tt>.
+      # +default+ is the type-casted default value, such as +new+ in <tt>sales_stage varchar(20) default 'new'</tt>.
+      # +cast_type+ is the object used for type casting and type information.
+      # +sql_type+ is used to extract the column's length, if necessary. For example +60+ in
+      # <tt>company_name varchar(60)</tt>.
+      # It will be mapped to one of the standard Rails SQL types in the <tt>type</tt> attribute.
+      # +null+ determines if this column allows +NULL+ values.
+      def initialize(name, default, cast_type, sql_type = nil, null = true)
+        @name             = name
+        @cast_type        = cast_type
+        @sql_type         = sql_type
+        @null             = null
+        @default          = default
+        @default_function = nil
+      end
+
+      def has_default?
+        !default.nil?
+      end
+
+      # Returns the human name of the column name.
+      #
+      # ===== Examples
+      #  Column.new('sales_stage', ...).human_name # => 'Sales stage'
+      def human_name
+        Base.human_attribute_name(@name)
+      end
+
+      def with_type(type)
+        dup.tap do |clone|
+          clone.instance_variable_set('@cast_type', type)
+        end
+      end
+    end
+  end
+  # :startdoc:
+end
diff --git a/activerecord/lib/active_record/connection_adapters/connection_specification.rb b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
new file mode 100644
index 0000000000..d28a54b8f9
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
@@ -0,0 +1,270 @@
+require 'uri'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionSpecification #:nodoc:
+      attr_reader :config, :adapter_method
+
+      def initialize(config, adapter_method)
+        @config, @adapter_method = config, adapter_method
+      end
+
+      def initialize_dup(original)
+        @config = original.config.dup
+      end
+
+      # Expands a connection string into a hash.
+      class ConnectionUrlResolver # :nodoc:
+
+        # == Example
+        #
+        #   url = "postgresql://foo:bar@localhost:9000/foo_test?pool=5&timeout=3000"
+        #   ConnectionUrlResolver.new(url).to_hash
+        #   # => {
+        #     "adapter"  => "postgresql",
+        #     "host"     => "localhost",
+        #     "port"     => 9000,
+        #     "database" => "foo_test",
+        #     "username" => "foo",
+        #     "password" => "bar",
+        #     "pool"     => "5",
+        #     "timeout"  => "3000"
+        #   }
+        def initialize(url)
+          raise "Database URL cannot be empty" if url.blank?
+          @uri     = uri_parser.parse(url)
+          @adapter = @uri.scheme.gsub('-', '_')
+          @adapter = "postgresql" if @adapter == "postgres"
+
+          if @uri.opaque
+            @uri.opaque, @query = @uri.opaque.split('?', 2)
+          else
+            @query = @uri.query
+          end
+        end
+
+        # Converts the given URL to a full connection hash.
+        def to_hash
+          config = raw_config.reject { |_,value| value.blank? }
+          config.map { |key,value| config[key] = uri_parser.unescape(value) if value.is_a? String }
+          config
+        end
+
+        private
+
+        def uri
+          @uri
+        end
+
+        def uri_parser
+          @uri_parser ||= URI::Parser.new
+        end
+
+        # Converts the query parameters of the URI into a hash.
+        #
+        #   "localhost?pool=5&reaping_frequency=2"
+        #   # => { "pool" => "5", "reaping_frequency" => "2" }
+        #
+        # returns empty hash if no query present.
+        #
+        #   "localhost"
+        #   # => {}
+        def query_hash
+          Hash[(@query || '').split("&").map { |pair| pair.split("=") }]
+        end
+
+        def raw_config
+          if uri.opaque
+            query_hash.merge({
+              "adapter"  => @adapter,
+              "database" => uri.opaque })
+          else
+            query_hash.merge({
+              "adapter"  => @adapter,
+              "username" => uri.user,
+              "password" => uri.password,
+              "port"     => uri.port,
+              "database" => database_from_path,
+              "host"     => uri.hostname })
+          end
+        end
+
+        # Returns name of the database.
+        def database_from_path
+          if @adapter == 'sqlite3'
+            # 'sqlite3:/foo' is absolute, because that makes sense. The
+            # corresponding relative version, 'sqlite3:foo', is handled
+            # elsewhere, as an "opaque".
+
+            uri.path
+          else
+            # Only SQLite uses a filename as the "database" name; for
+            # anything else, a leading slash would be silly.
+
+            uri.path.sub(%r{^/}, "")
+          end
+        end
+      end
+
+      ##
+      # Builds a ConnectionSpecification from user input.
+      class Resolver # :nodoc:
+        attr_reader :configurations
+
+        # Accepts a hash two layers deep, keys on the first layer represent
+        # environments such as "production". Keys must be strings.
+        def initialize(configurations)
+          @configurations = configurations
+        end
+
+        # Returns a hash with database connection information.
+        #
+        # == Examples
+        #
+        # Full hash Configuration.
+        #
+        #   configurations = { "production" => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3" } }
+        #   Resolver.new(configurations).resolve(:production)
+        #   # => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3"}
+        #
+        # Initialized with URL configuration strings.
+        #
+        #   configurations = { "production" => "postgresql://localhost/foo" }
+        #   Resolver.new(configurations).resolve(:production)
+        #   # => { "host" => "localhost", "database" => "foo", "adapter" => "postgresql" }
+        #
+        def resolve(config)
+          if config
+            resolve_connection config
+          elsif env = ActiveRecord::ConnectionHandling::RAILS_ENV.call
+            resolve_symbol_connection env.to_sym
+          else
+            raise AdapterNotSpecified
+          end
+        end
+
+        # Expands each key in @configurations hash into fully resolved hash
+        def resolve_all
+          config = configurations.dup
+          config.each do |key, value|
+            config[key] = resolve(value) if value
+          end
+          config
+        end
+
+        # Returns an instance of ConnectionSpecification for a given adapter.
+        # Accepts a hash one layer deep that contains all connection information.
+        #
+        # == Example
+        #
+        #   config = { "production" => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3" } }
+        #   spec = Resolver.new(config).spec(:production)
+        #   spec.adapter_method
+        #   # => "sqlite3_connection"
+        #   spec.config
+        #   # => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3" }
+        #
+        def spec(config)
+          spec = resolve(config).symbolize_keys
+
+          raise(AdapterNotSpecified, "database configuration does not specify adapter") unless spec.key?(:adapter)
+
+          path_to_adapter = "active_record/connection_adapters/#{spec[:adapter]}_adapter"
+          begin
+            require path_to_adapter
+          rescue Gem::LoadError => e
+            raise Gem::LoadError, "Specified '#{spec[:adapter]}' for database adapter, but the gem is not loaded. Add `gem '#{e.name}'` to your Gemfile (and ensure its version is at the minimum required by ActiveRecord)."
+          rescue LoadError => e
+            raise LoadError, "Could not load '#{path_to_adapter}'. Make sure that the adapter in config/database.yml is valid. If you use an adapter other than 'mysql', 'mysql2', 'postgresql' or 'sqlite3' add the necessary adapter gem to the Gemfile.", e.backtrace
+          end
+
+          adapter_method = "#{spec[:adapter]}_connection"
+          ConnectionSpecification.new(spec, adapter_method)
+        end
+
+        private
+
+        # Returns fully resolved connection, accepts hash, string or symbol.
+        # Always returns a hash.
+        #
+        # == Examples
+        #
+        # Symbol representing current environment.
+        #
+        #   Resolver.new("production" => {}).resolve_connection(:production)
+        #   # => {}
+        #
+        # One layer deep hash of connection values.
+        #
+        #   Resolver.new({}).resolve_connection("adapter" => "sqlite3")
+        #   # => { "adapter" => "sqlite3" }
+        #
+        # Connection URL.
+        #
+        #   Resolver.new({}).resolve_connection("postgresql://localhost/foo")
+        #   # => { "host" => "localhost", "database" => "foo", "adapter" => "postgresql" }
+        #
+        def resolve_connection(spec)
+          case spec
+          when Symbol
+            resolve_symbol_connection spec
+          when String
+            resolve_string_connection spec
+          when Hash
+            resolve_hash_connection spec
+          end
+        end
+
+        def resolve_string_connection(spec)
+          # Rails has historically accepted a string to mean either
+          # an environment key or a URL spec, so we have deprecated
+          # this ambiguous behaviour and in the future this function
+          # can be removed in favor of resolve_url_connection.
+          if configurations.key?(spec) || spec !~ /:/
+            ActiveSupport::Deprecation.warn "Passing a string to ActiveRecord::Base.establish_connection " \
+              "for a configuration lookup is deprecated, please pass a symbol (#{spec.to_sym.inspect}) instead"
+            resolve_symbol_connection(spec)
+          else
+            resolve_url_connection(spec)
+          end
+        end
+
+        # Takes the environment such as `:production` or `:development`.
+        # This requires that the @configurations was initialized with a key that
+        # matches.
+        #
+        #   Resolver.new("production" => {}).resolve_symbol_connection(:production)
+        #   # => {}
+        #
+        def resolve_symbol_connection(spec)
+          if config = configurations[spec.to_s]
+            resolve_connection(config)
+          else
+            raise(AdapterNotSpecified, "'#{spec}' database is not configured. Available: #{configurations.keys.inspect}")
+          end
+        end
+
+        # Accepts a hash. Expands the "url" key that contains a
+        # URL database connection to a full connection
+        # hash and merges with the rest of the hash.
+        # Connection details inside of the "url" key win any merge conflicts
+        def resolve_hash_connection(spec)
+          if spec["url"] && spec["url"] !~ /^jdbc:/
+            connection_hash = resolve_url_connection(spec.delete("url"))
+            spec.merge!(connection_hash)
+          end
+          spec
+        end
+
+        # Takes a connection URL.
+        #
+        #   Resolver.new({}).resolve_url_connection("postgresql://localhost/foo")
+        #   # => { "host" => "localhost", "database" => "foo", "adapter" => "postgresql" }
+        #
+        def resolve_url_connection(url)
+          ConnectionUrlResolver.new(url).to_hash
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
new file mode 100644
index 0000000000..39d52e6349
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -0,0 +1,281 @@
+require 'active_record/connection_adapters/abstract_mysql_adapter'
+
+gem 'mysql2', '~> 0.3.13'
+require 'mysql2'
+
+module ActiveRecord
+  module ConnectionHandling # :nodoc:
+    # Establishes a connection to the database that's used by all Active Record objects.
+    def mysql2_connection(config)
+      config = config.symbolize_keys
+
+      config[:username] = 'root' if config[:username].nil?
+
+      if Mysql2::Client.const_defined? :FOUND_ROWS
+        config[:flags] = Mysql2::Client::FOUND_ROWS
+      end
+
+      client = Mysql2::Client.new(config)
+      options = [config[:host], config[:username], config[:password], config[:database], config[:port], config[:socket], 0]
+      ConnectionAdapters::Mysql2Adapter.new(client, logger, options, config)
+    rescue Mysql2::Error => error
+      if error.message.include?("Unknown database")
+        raise ActiveRecord::NoDatabaseError.new(error.message, error)
+      else
+        raise
+      end
+    end
+  end
+
+  module ConnectionAdapters
+    class Mysql2Adapter < AbstractMysqlAdapter
+      ADAPTER_NAME = 'Mysql2'
+
+      def initialize(connection, logger, connection_options, config)
+        super
+        @prepared_statements = false
+        configure_connection
+      end
+
+      MAX_INDEX_LENGTH_FOR_UTF8MB4 = 191
+      def initialize_schema_migrations_table
+        if @config[:encoding] == 'utf8mb4'
+          ActiveRecord::SchemaMigration.create_table(MAX_INDEX_LENGTH_FOR_UTF8MB4)
+        else
+          ActiveRecord::SchemaMigration.create_table
+        end
+      end
+
+      def supports_explain?
+        true
+      end
+
+      # HELPER METHODS ===========================================
+
+      def each_hash(result) # :nodoc:
+        if block_given?
+          result.each(:as => :hash, :symbolize_keys => true) do |row|
+            yield row
+          end
+        else
+          to_enum(:each_hash, result)
+        end
+      end
+
+      def error_number(exception)
+        exception.error_number if exception.respond_to?(:error_number)
+      end
+
+      # QUOTING ==================================================
+
+      def quote_string(string)
+        @connection.escape(string)
+      end
+
+      def quoted_date(value)
+        if value.acts_like?(:time) && value.respond_to?(:usec)
+          "#{super}.#{sprintf("%06d", value.usec)}"
+        else
+          super
+        end
+      end
+
+      # CONNECTION MANAGEMENT ====================================
+
+      def active?
+        return false unless @connection
+        @connection.ping
+      end
+
+      def reconnect!
+        super
+        disconnect!
+        connect
+      end
+      alias :reset! :reconnect!
+
+      # Disconnects from the database if already connected.
+      # Otherwise, this method does nothing.
+      def disconnect!
+        super
+        unless @connection.nil?
+          @connection.close
+          @connection = nil
+        end
+      end
+
+      # DATABASE STATEMENTS ======================================
+
+      def explain(arel, binds = [])
+        sql     = "EXPLAIN #{to_sql(arel, binds.dup)}"
+        start   = Time.now
+        result  = exec_query(sql, 'EXPLAIN', binds)
+        elapsed = Time.now - start
+
+        ExplainPrettyPrinter.new.pp(result, elapsed)
+      end
+
+      class ExplainPrettyPrinter # :nodoc:
+        # Pretty prints the result of a EXPLAIN in a way that resembles the output of the
+        # MySQL shell:
+        #
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   | id | select_type | table | type  | possible_keys | key     | key_len | ref   | rows | Extra       |
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   |  1 | SIMPLE      | users | const | PRIMARY       | PRIMARY | 4       | const |    1 |             |
+        #   |  1 | SIMPLE      | posts | ALL   | NULL          | NULL    | NULL    | NULL  |    1 | Using where |
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   2 rows in set (0.00 sec)
+        #
+        # This is an exercise in Ruby hyperrealism :).
+        def pp(result, elapsed)
+          widths    = compute_column_widths(result)
+          separator = build_separator(widths)
+
+          pp = []
+
+          pp << separator
+          pp << build_cells(result.columns, widths)
+          pp << separator
+
+          result.rows.each do |row|
+            pp << build_cells(row, widths)
+          end
+
+          pp << separator
+          pp << build_footer(result.rows.length, elapsed)
+
+          pp.join("\n") + "\n"
+        end
+
+        private
+
+        def compute_column_widths(result)
+          [].tap do |widths|
+            result.columns.each_with_index do |column, i|
+              cells_in_column = [column] + result.rows.map {|r| r[i].nil? ? 'NULL' : r[i].to_s}
+              widths << cells_in_column.map(&:length).max
+            end
+          end
+        end
+
+        def build_separator(widths)
+          padding = 1
+          '+' + widths.map {|w| '-' * (w + (padding*2))}.join('+') + '+'
+        end
+
+        def build_cells(items, widths)
+          cells = []
+          items.each_with_index do |item, i|
+            item = 'NULL' if item.nil?
+            justifier = item.is_a?(Numeric) ? 'rjust' : 'ljust'
+            cells << item.to_s.send(justifier, widths[i])
+          end
+          '| ' + cells.join(' | ') + ' |'
+        end
+
+        def build_footer(nrows, elapsed)
+          rows_label = nrows == 1 ? 'row' : 'rows'
+          "#{nrows} #{rows_label} in set (%.2f sec)" % elapsed
+        end
+      end
+
+      # FIXME: re-enable the following once a "better" query_cache solution is in core
+      #
+      # The overrides below perform much better than the originals in AbstractAdapter
+      # because we're able to take advantage of mysql2's lazy-loading capabilities
+      #
+      # # Returns a record hash with the column names as keys and column values
+      # # as values.
+      # def select_one(sql, name = nil)
+      #   result = execute(sql, name)
+      #   result.each(as: :hash) do |r|
+      #     return r
+      #   end
+      # end
+      #
+      # # Returns a single value from a record
+      # def select_value(sql, name = nil)
+      #   result = execute(sql, name)
+      #   if first = result.first
+      #     first.first
+      #   end
+      # end
+      #
+      # # Returns an array of the values of the first column in a select:
+      # #   select_values("SELECT id FROM companies LIMIT 3") => [1,2,3]
+      # def select_values(sql, name = nil)
+      #   execute(sql, name).map { |row| row.first }
+      # end
+
+      # Returns an array of arrays containing the field values.
+      # Order is the same as that returned by +columns+.
+      def select_rows(sql, name = nil, binds = [])
+        execute(sql, name).to_a
+      end
+
+      # Executes the SQL statement in the context of this connection.
+      def execute(sql, name = nil)
+        if @connection
+          # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
+          # made since we established the connection
+          @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
+        end
+
+        super
+      end
+
+      def exec_query(sql, name = 'SQL', binds = [])
+        result = execute(sql, name)
+        ActiveRecord::Result.new(result.fields, result.to_a)
+      end
+
+      alias exec_without_stmt exec_query
+
+      # Returns an ActiveRecord::Result instance.
+      def select(sql, name = nil, binds = [])
+        exec_query(sql, name)
+      end
+
+      def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
+        super
+        id_value || @connection.last_id
+      end
+      alias :create :insert_sql
+
+      def exec_insert(sql, name, binds, pk = nil, sequence_name = nil)
+        execute to_sql(sql, binds), name
+      end
+
+      def exec_delete(sql, name, binds)
+        execute to_sql(sql, binds), name
+        @connection.affected_rows
+      end
+      alias :exec_update :exec_delete
+
+      def last_inserted_id(result)
+        @connection.last_id
+      end
+
+      private
+
+      def connect
+        @connection = Mysql2::Client.new(@config)
+        configure_connection
+      end
+
+      def configure_connection
+        @connection.query_options.merge!(:as => :array)
+        super
+      end
+
+      def full_version
+        @full_version ||= @connection.info[:version]
+      end
+
+      def set_field_encoding field_name
+        field_name
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
new file mode 100644
index 0000000000..a03bc28744
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -0,0 +1,487 @@
+require 'active_record/connection_adapters/abstract_mysql_adapter'
+require 'active_record/connection_adapters/statement_pool'
+require 'active_support/core_ext/hash/keys'
+
+gem 'mysql', '~> 2.9'
+require 'mysql'
+
+class Mysql
+  class Time
+    def to_date
+      Date.new(year, month, day)
+    end
+  end
+  class Stmt; include Enumerable end
+  class Result; include Enumerable end
+end
+
+module ActiveRecord
+  module ConnectionHandling # :nodoc:
+    # Establishes a connection to the database that's used by all Active Record objects.
+    def mysql_connection(config)
+      config = config.symbolize_keys
+      host     = config[:host]
+      port     = config[:port]
+      socket   = config[:socket]
+      username = config[:username] ? config[:username].to_s : 'root'
+      password = config[:password].to_s
+      database = config[:database]
+
+      mysql = Mysql.init
+      mysql.ssl_set(config[:sslkey], config[:sslcert], config[:sslca], config[:sslcapath], config[:sslcipher]) if config[:sslca] || config[:sslkey]
+
+      default_flags = Mysql.const_defined?(:CLIENT_MULTI_RESULTS) ? Mysql::CLIENT_MULTI_RESULTS : 0
+      default_flags |= Mysql::CLIENT_FOUND_ROWS if Mysql.const_defined?(:CLIENT_FOUND_ROWS)
+      options = [host, username, password, database, port, socket, default_flags]
+      ConnectionAdapters::MysqlAdapter.new(mysql, logger, options, config)
+    rescue Mysql::Error => error
+      if error.message.include?("Unknown database")
+        raise ActiveRecord::NoDatabaseError.new(error.message, error)
+      else
+        raise
+      end
+    end
+  end
+
+  module ConnectionAdapters
+    # The MySQL adapter will work with both Ruby/MySQL, which is a Ruby-based MySQL adapter that comes bundled with Active Record, and with
+    # the faster C-based MySQL/Ruby adapter (available both as a gem and from http://www.tmtm.org/en/mysql/ruby/).
+    #
+    # Options:
+    #
+    # * <tt>:host</tt> - Defaults to "localhost".
+    # * <tt>:port</tt> - Defaults to 3306.
+    # * <tt>:socket</tt> - Defaults to "/tmp/mysql.sock".
+    # * <tt>:username</tt> - Defaults to "root"
+    # * <tt>:password</tt> - Defaults to nothing.
+    # * <tt>:database</tt> - The name of the database. No default, must be provided.
+    # * <tt>:encoding</tt> - (Optional) Sets the client encoding by executing "SET NAMES <encoding>" after connection.
+    # * <tt>:reconnect</tt> - Defaults to false (See MySQL documentation: http://dev.mysql.com/doc/refman/5.0/en/auto-reconnect.html).
+    # * <tt>:strict</tt> - Defaults to true. Enable STRICT_ALL_TABLES. (See MySQL documentation: http://dev.mysql.com/doc/refman/5.0/en/server-sql-mode.html)
+    # * <tt>:variables</tt> - (Optional) A hash session variables to send as `SET @@SESSION.key = value` on each database connection. Use the value `:default` to set a variable to its DEFAULT value. (See MySQL documentation: http://dev.mysql.com/doc/refman/5.0/en/set-statement.html).
+    # * <tt>:sslca</tt> - Necessary to use MySQL with an SSL connection.
+    # * <tt>:sslkey</tt> - Necessary to use MySQL with an SSL connection.
+    # * <tt>:sslcert</tt> - Necessary to use MySQL with an SSL connection.
+    # * <tt>:sslcapath</tt> - Necessary to use MySQL with an SSL connection.
+    # * <tt>:sslcipher</tt> - Necessary to use MySQL with an SSL connection.
+    #
+    class MysqlAdapter < AbstractMysqlAdapter
+      ADAPTER_NAME = 'MySQL'
+
+      class StatementPool < ConnectionAdapters::StatementPool
+        def initialize(connection, max = 1000)
+          super
+          @cache = Hash.new { |h,pid| h[pid] = {} }
+        end
+
+        def each(&block); cache.each(&block); end
+        def key?(key);    cache.key?(key); end
+        def [](key);      cache[key]; end
+        def length;       cache.length; end
+        def delete(key);  cache.delete(key); end
+
+        def []=(sql, key)
+          while @max <= cache.size
+            cache.shift.last[:stmt].close
+          end
+          cache[sql] = key
+        end
+
+        def clear
+          cache.values.each do |hash|
+            hash[:stmt].close
+          end
+          cache.clear
+        end
+
+        private
+        def cache
+          @cache[Process.pid]
+        end
+      end
+
+      def initialize(connection, logger, connection_options, config)
+        super
+        @statements = StatementPool.new(@connection,
+                                        self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 }))
+        @client_encoding = nil
+        connect
+      end
+
+      # Returns true, since this connection adapter supports prepared statement
+      # caching.
+      def supports_statement_cache?
+        true
+      end
+
+      # HELPER METHODS ===========================================
+
+      def each_hash(result) # :nodoc:
+        if block_given?
+          result.each_hash do |row|
+            row.symbolize_keys!
+            yield row
+          end
+        else
+          to_enum(:each_hash, result)
+        end
+      end
+
+      def error_number(exception) # :nodoc:
+        exception.errno if exception.respond_to?(:errno)
+      end
+
+      # QUOTING ==================================================
+
+      def quote_string(string) #:nodoc:
+        @connection.quote(string)
+      end
+
+      # CONNECTION MANAGEMENT ====================================
+
+      def active?
+        if @connection.respond_to?(:stat)
+          @connection.stat
+        else
+          @connection.query 'select 1'
+        end
+
+        # mysql-ruby doesn't raise an exception when stat fails.
+        if @connection.respond_to?(:errno)
+          @connection.errno.zero?
+        else
+          true
+        end
+      rescue Mysql::Error
+        false
+      end
+
+      def reconnect!
+        super
+        disconnect!
+        connect
+      end
+
+      # Disconnects from the database if already connected. Otherwise, this
+      # method does nothing.
+      def disconnect!
+        super
+        @connection.close rescue nil
+      end
+
+      def reset!
+        if @connection.respond_to?(:change_user)
+          # See http://bugs.mysql.com/bug.php?id=33540 -- the workaround way to
+          # reset the connection is to change the user to the same user.
+          @connection.change_user(@config[:username], @config[:password], @config[:database])
+          configure_connection
+        end
+      end
+
+      # DATABASE STATEMENTS ======================================
+
+      def select_rows(sql, name = nil, binds = [])
+        @connection.query_with_result = true
+        rows = exec_query(sql, name, binds).rows
+        @connection.more_results && @connection.next_result    # invoking stored procedures with CLIENT_MULTI_RESULTS requires this to tidy up else connection will be dropped
+        rows
+      end
+
+      # Clears the prepared statements cache.
+      def clear_cache!
+        super
+        @statements.clear
+      end
+
+      # Taken from here:
+      #   https://github.com/tmtm/ruby-mysql/blob/master/lib/mysql/charset.rb
+      # Author: TOMITA Masahiro <tommy@tmtm.org>
+      ENCODINGS = {
+        "armscii8" => nil,
+        "ascii"    => Encoding::US_ASCII,
+        "big5"     => Encoding::Big5,
+        "binary"   => Encoding::ASCII_8BIT,
+        "cp1250"   => Encoding::Windows_1250,
+        "cp1251"   => Encoding::Windows_1251,
+        "cp1256"   => Encoding::Windows_1256,
+        "cp1257"   => Encoding::Windows_1257,
+        "cp850"    => Encoding::CP850,
+        "cp852"    => Encoding::CP852,
+        "cp866"    => Encoding::IBM866,
+        "cp932"    => Encoding::Windows_31J,
+        "dec8"     => nil,
+        "eucjpms"  => Encoding::EucJP_ms,
+        "euckr"    => Encoding::EUC_KR,
+        "gb2312"   => Encoding::EUC_CN,
+        "gbk"      => Encoding::GBK,
+        "geostd8"  => nil,
+        "greek"    => Encoding::ISO_8859_7,
+        "hebrew"   => Encoding::ISO_8859_8,
+        "hp8"      => nil,
+        "keybcs2"  => nil,
+        "koi8r"    => Encoding::KOI8_R,
+        "koi8u"    => Encoding::KOI8_U,
+        "latin1"   => Encoding::ISO_8859_1,
+        "latin2"   => Encoding::ISO_8859_2,
+        "latin5"   => Encoding::ISO_8859_9,
+        "latin7"   => Encoding::ISO_8859_13,
+        "macce"    => Encoding::MacCentEuro,
+        "macroman" => Encoding::MacRoman,
+        "sjis"     => Encoding::SHIFT_JIS,
+        "swe7"     => nil,
+        "tis620"   => Encoding::TIS_620,
+        "ucs2"     => Encoding::UTF_16BE,
+        "ujis"     => Encoding::EucJP_ms,
+        "utf8"     => Encoding::UTF_8,
+        "utf8mb4"  => Encoding::UTF_8,
+      }
+
+      # Get the client encoding for this database
+      def client_encoding
+        return @client_encoding if @client_encoding
+
+        result = exec_query(
+          "SHOW VARIABLES WHERE Variable_name = 'character_set_client'",
+          'SCHEMA')
+        @client_encoding = ENCODINGS[result.rows.last.last]
+      end
+
+      def exec_query(sql, name = 'SQL', binds = [])
+        if without_prepared_statement?(binds)
+          result_set, affected_rows = exec_without_stmt(sql, name)
+        else
+          result_set, affected_rows = exec_stmt(sql, name, binds)
+        end
+
+        yield affected_rows if block_given?
+
+        result_set
+      end
+
+      def last_inserted_id(result)
+        @connection.insert_id
+      end
+
+      module Fields # :nodoc:
+        class DateTime < Type::DateTime # :nodoc:
+          def cast_value(value)
+            if Mysql::Time === value
+              new_time(
+                value.year,
+                value.month,
+                value.day,
+                value.hour,
+                value.minute,
+                value.second,
+                value.second_part)
+            else
+              super
+            end
+          end
+        end
+
+        class Time < Type::Time # :nodoc:
+          def cast_value(value)
+            if Mysql::Time === value
+              new_time(
+                2000,
+                01,
+                01,
+                value.hour,
+                value.minute,
+                value.second,
+                value.second_part)
+            else
+              super
+            end
+          end
+        end
+
+        class << self
+          TYPES = Type::HashLookupTypeMap.new # :nodoc:
+
+          delegate :register_type, :alias_type, to: :TYPES
+
+          def find_type(field)
+            if field.type == Mysql::Field::TYPE_TINY && field.length > 1
+              TYPES.lookup(Mysql::Field::TYPE_LONG)
+            else
+              TYPES.lookup(field.type)
+            end
+          end
+        end
+
+        register_type Mysql::Field::TYPE_TINY,    Type::Boolean.new
+        register_type Mysql::Field::TYPE_LONG,    Type::Integer.new
+        alias_type Mysql::Field::TYPE_LONGLONG,   Mysql::Field::TYPE_LONG
+        alias_type Mysql::Field::TYPE_NEWDECIMAL, Mysql::Field::TYPE_LONG
+
+        register_type Mysql::Field::TYPE_DATE, Type::Date.new
+        register_type Mysql::Field::TYPE_DATETIME, Fields::DateTime.new
+        register_type Mysql::Field::TYPE_TIME, Fields::Time.new
+        register_type Mysql::Field::TYPE_FLOAT, Type::Float.new
+      end
+
+      def initialize_type_map(m) # :nodoc:
+        super
+        m.register_type %r(datetime)i, Fields::DateTime.new
+        m.register_type %r(time)i,     Fields::Time.new
+      end
+
+      def exec_without_stmt(sql, name = 'SQL') # :nodoc:
+        # Some queries, like SHOW CREATE TABLE don't work through the prepared
+        # statement API. For those queries, we need to use this method. :'(
+        log(sql, name) do
+          result = @connection.query(sql)
+          affected_rows = @connection.affected_rows
+
+          if result
+            types = {}
+            fields = []
+            result.fetch_fields.each { |field|
+              field_name = field.name
+              fields << field_name
+
+              if field.decimals > 0
+                types[field_name] = Type::Decimal.new
+              else
+                types[field_name] = Fields.find_type field
+              end
+            }
+
+            result_set = ActiveRecord::Result.new(fields, result.to_a, types)
+            result.free
+          else
+            result_set = ActiveRecord::Result.new([], [])
+          end
+
+          [result_set, affected_rows]
+        end
+      end
+
+      def execute_and_free(sql, name = nil) # :nodoc:
+        result = execute(sql, name)
+        ret = yield result
+        result.free
+        ret
+      end
+
+      def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) #:nodoc:
+        super sql, name
+        id_value || @connection.insert_id
+      end
+      alias :create :insert_sql
+
+      def exec_delete(sql, name, binds) # :nodoc:
+        affected_rows = 0
+
+        exec_query(sql, name, binds) do |n|
+          affected_rows = n
+        end
+
+        affected_rows
+      end
+      alias :exec_update :exec_delete
+
+      def begin_db_transaction #:nodoc:
+        exec_query "BEGIN"
+      end
+
+      private
+
+      def exec_stmt(sql, name, binds)
+        cache = {}
+        type_casted_binds = binds.map { |col, val|
+          [col, type_cast(val, col)]
+        }
+
+        log(sql, name, type_casted_binds) do
+          if binds.empty?
+            stmt = @connection.prepare(sql)
+          else
+            cache = @statements[sql] ||= {
+              :stmt => @connection.prepare(sql)
+            }
+            stmt = cache[:stmt]
+          end
+
+          begin
+            stmt.execute(*type_casted_binds.map { |_, val| val })
+          rescue Mysql::Error => e
+            # Older versions of MySQL leave the prepared statement in a bad
+            # place when an error occurs. To support older MySQL versions, we
+            # need to close the statement and delete the statement from the
+            # cache.
+            stmt.close
+            @statements.delete sql
+            raise e
+          end
+
+          cols = nil
+          if metadata = stmt.result_metadata
+            cols = cache[:cols] ||= metadata.fetch_fields.map { |field|
+              field.name
+            }
+            metadata.free
+          end
+
+          result_set = ActiveRecord::Result.new(cols, stmt.to_a) if cols
+          affected_rows = stmt.affected_rows
+
+          stmt.free_result
+          stmt.close if binds.empty?
+
+          [result_set, affected_rows]
+        end
+      end
+
+      def connect
+        encoding = @config[:encoding]
+        if encoding
+          @connection.options(Mysql::SET_CHARSET_NAME, encoding) rescue nil
+        end
+
+        if @config[:sslca] || @config[:sslkey]
+          @connection.ssl_set(@config[:sslkey], @config[:sslcert], @config[:sslca], @config[:sslcapath], @config[:sslcipher])
+        end
+
+        @connection.options(Mysql::OPT_CONNECT_TIMEOUT, @config[:connect_timeout]) if @config[:connect_timeout]
+        @connection.options(Mysql::OPT_READ_TIMEOUT, @config[:read_timeout]) if @config[:read_timeout]
+        @connection.options(Mysql::OPT_WRITE_TIMEOUT, @config[:write_timeout]) if @config[:write_timeout]
+
+        @connection.real_connect(*@connection_options)
+
+        # reconnect must be set after real_connect is called, because real_connect sets it to false internally
+        @connection.reconnect = !!@config[:reconnect] if @connection.respond_to?(:reconnect=)
+
+        configure_connection
+      end
+
+      # Many Rails applications monkey-patch a replacement of the configure_connection method
+      # and don't call 'super', so leave this here even though it looks superfluous.
+      def configure_connection
+        super
+      end
+
+      def select(sql, name = nil, binds = [])
+        @connection.query_with_result = true
+        rows = exec_query(sql, name, binds)
+        @connection.more_results && @connection.next_result    # invoking stored procedures with CLIENT_MULTI_RESULTS requires this to tidy up else connection will be dropped
+        rows
+      end
+
+      # Returns the full version of the connected MySQL server.
+      def full_version
+        @full_version ||= @connection.server_info
+      end
+
+      def set_field_encoding field_name
+        field_name.force_encoding(client_encoding)
+        if internal_enc = Encoding.default_internal
+          field_name = field_name.encode!(internal_enc)
+        end
+        field_name
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb b/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb
new file mode 100644
index 0000000000..1b74c039ce
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb
@@ -0,0 +1,93 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module ArrayParser # :nodoc:
+
+        DOUBLE_QUOTE = '"'
+        BACKSLASH = "\\"
+        COMMA = ','
+        BRACKET_OPEN = '{'
+        BRACKET_CLOSE = '}'
+
+        def parse_pg_array(string) # :nodoc:
+          local_index = 0
+          array = []
+          while(local_index < string.length)
+            case string[local_index]
+            when BRACKET_OPEN
+              local_index,array = parse_array_contents(array, string, local_index + 1)
+            when BRACKET_CLOSE
+              return array
+            end
+            local_index += 1
+          end
+
+          array
+        end
+
+        private
+
+          def parse_array_contents(array, string, index)
+            is_escaping  = false
+            is_quoted    = false
+            was_quoted   = false
+            current_item = ''
+
+            local_index = index
+            while local_index
+              token = string[local_index]
+              if is_escaping
+                current_item << token
+                is_escaping = false
+              else
+                if is_quoted
+                  case token
+                  when DOUBLE_QUOTE
+                    is_quoted = false
+                    was_quoted = true
+                  when BACKSLASH
+                    is_escaping = true
+                  else
+                    current_item << token
+                  end
+                else
+                  case token
+                  when BACKSLASH
+                    is_escaping = true
+                  when COMMA
+                    add_item_to_array(array, current_item, was_quoted)
+                    current_item = ''
+                    was_quoted = false
+                  when DOUBLE_QUOTE
+                    is_quoted = true
+                  when BRACKET_OPEN
+                    internal_items = []
+                    local_index,internal_items = parse_array_contents(internal_items, string, local_index + 1)
+                    array.push(internal_items)
+                  when BRACKET_CLOSE
+                    add_item_to_array(array, current_item, was_quoted)
+                    return local_index,array
+                  else
+                    current_item << token
+                  end
+                end
+              end
+
+              local_index += 1
+            end
+            return local_index,array
+          end
+
+          def add_item_to_array(array, current_item, quoted)
+            return if !quoted && current_item.length == 0
+
+            if !quoted && current_item == 'NULL'
+              array.push nil
+            else
+              array.push current_item
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/column.rb b/activerecord/lib/active_record/connection_adapters/postgresql/column.rb
new file mode 100644
index 0000000000..37e5c3859c
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/column.rb
@@ -0,0 +1,20 @@
+module ActiveRecord
+  module ConnectionAdapters
+    # PostgreSQL-specific extensions to column definitions in a table.
+    class PostgreSQLColumn < Column #:nodoc:
+      attr_accessor :array
+
+      def initialize(name, default, cast_type, sql_type = nil, null = true, default_function = nil)
+        if sql_type =~ /\[\]$/
+          @array = true
+          super(name, default, cast_type, sql_type[0..sql_type.length - 3], null)
+        else
+          @array = false
+          super(name, default, cast_type, sql_type, null)
+        end
+
+        @default_function = default_function
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
new file mode 100644
index 0000000000..89a7257d77
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
@@ -0,0 +1,236 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module DatabaseStatements
+        def explain(arel, binds = [])
+          sql = "EXPLAIN #{to_sql(arel, binds)}"
+          ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
+        end
+
+        class ExplainPrettyPrinter # :nodoc:
+          # Pretty prints the result of a EXPLAIN in a way that resembles the output of the
+          # PostgreSQL shell:
+          #
+          #                                     QUERY PLAN
+          #   ------------------------------------------------------------------------------
+          #    Nested Loop Left Join  (cost=0.00..37.24 rows=8 width=0)
+          #      Join Filter: (posts.user_id = users.id)
+          #      ->  Index Scan using users_pkey on users  (cost=0.00..8.27 rows=1 width=4)
+          #            Index Cond: (id = 1)
+          #      ->  Seq Scan on posts  (cost=0.00..28.88 rows=8 width=4)
+          #            Filter: (posts.user_id = 1)
+          #   (6 rows)
+          #
+          def pp(result)
+            header = result.columns.first
+            lines  = result.rows.map(&:first)
+
+            # We add 2 because there's one char of padding at both sides, note
+            # the extra hyphens in the example above.
+            width = [header, *lines].map(&:length).max + 2
+
+            pp = []
+
+            pp << header.center(width).rstrip
+            pp << '-' * width
+
+            pp += lines.map {|line| " #{line}"}
+
+            nrows = result.rows.length
+            rows_label = nrows == 1 ? 'row' : 'rows'
+            pp << "(#{nrows} #{rows_label})"
+
+            pp.join("\n") + "\n"
+          end
+        end
+
+        def select_value(arel, name = nil, binds = [])
+          arel, binds = binds_from_relation arel, binds
+          sql = to_sql(arel, binds)
+          execute_and_clear(sql, name, binds) do |result|
+            result.getvalue(0, 0) if result.ntuples > 0 && result.nfields > 0
+          end
+        end
+
+        def select_values(arel, name = nil)
+          arel, binds = binds_from_relation arel, []
+          sql = to_sql(arel, binds)
+          execute_and_clear(sql, name, binds) do |result|
+            if result.nfields > 0
+              result.column_values(0)
+            else
+              []
+            end
+          end
+        end
+
+        # Executes a SELECT query and returns an array of rows. Each row is an
+        # array of field values.
+        def select_rows(sql, name = nil, binds = [])
+          execute_and_clear(sql, name, binds) do |result|
+            result.values
+          end
+        end
+
+        # Executes an INSERT query and returns the new record's ID
+        def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
+          unless pk
+            # Extract the table from the insert sql. Yuck.
+            table_ref = extract_table_ref_from_insert_sql(sql)
+            pk = primary_key(table_ref) if table_ref
+          end
+
+          if pk && use_insert_returning?
+            select_value("#{sql} RETURNING #{quote_column_name(pk)}")
+          elsif pk
+            super
+            last_insert_id_value(sequence_name || default_sequence_name(table_ref, pk))
+          else
+            super
+          end
+        end
+
+        def create
+          super.insert
+        end
+
+        # The internal PostgreSQL identifier of the money data type.
+        MONEY_COLUMN_TYPE_OID = 790 #:nodoc:
+        # The internal PostgreSQL identifier of the BYTEA data type.
+        BYTEA_COLUMN_TYPE_OID = 17 #:nodoc:
+
+        # create a 2D array representing the result set
+        def result_as_array(res) #:nodoc:
+          # check if we have any binary column and if they need escaping
+          ftypes = Array.new(res.nfields) do |i|
+            [i, res.ftype(i)]
+          end
+
+          rows = res.values
+          return rows unless ftypes.any? { |_, x|
+            x == BYTEA_COLUMN_TYPE_OID || x == MONEY_COLUMN_TYPE_OID
+          }
+
+          typehash = ftypes.group_by { |_, type| type }
+          binaries = typehash[BYTEA_COLUMN_TYPE_OID] || []
+          monies   = typehash[MONEY_COLUMN_TYPE_OID] || []
+
+          rows.each do |row|
+            # unescape string passed BYTEA field (OID == 17)
+            binaries.each do |index, _|
+              row[index] = unescape_bytea(row[index])
+            end
+
+            # If this is a money type column and there are any currency symbols,
+            # then strip them off. Indeed it would be prettier to do this in
+            # PostgreSQLColumn.string_to_decimal but would break form input
+            # fields that call value_before_type_cast.
+            monies.each do |index, _|
+              data = row[index]
+              # Because money output is formatted according to the locale, there are two
+              # cases to consider (note the decimal separators):
+              #  (1) $12,345,678.12
+              #  (2) $12.345.678,12
+              case data
+              when /^-?\D+[\d,]+\.\d{2}$/  # (1)
+                data.gsub!(/[^-\d.]/, '')
+              when /^-?\D+[\d.]+,\d{2}$/  # (2)
+                data.gsub!(/[^-\d,]/, '').sub!(/,/, '.')
+              end
+            end
+          end
+        end
+
+        # Queries the database and returns the results in an Array-like object
+        def query(sql, name = nil) #:nodoc:
+          log(sql, name) do
+            result_as_array @connection.async_exec(sql)
+          end
+        end
+
+        # Executes an SQL statement, returning a PGresult object on success
+        # or raising a PGError exception otherwise.
+        def execute(sql, name = nil)
+          log(sql, name) do
+            @connection.async_exec(sql)
+          end
+        end
+
+        def substitute_at(column, index)
+          Arel::Nodes::BindParam.new "$#{index + 1}"
+        end
+
+        def exec_query(sql, name = 'SQL', binds = [])
+          execute_and_clear(sql, name, binds) do |result|
+            types = {}
+            fields = result.fields
+            fields.each_with_index do |fname, i|
+              ftype = result.ftype i
+              fmod  = result.fmod i
+              types[fname] = get_oid_type(ftype, fmod, fname)
+            end
+            ActiveRecord::Result.new(fields, result.values, types)
+          end
+        end
+
+        def exec_delete(sql, name = 'SQL', binds = [])
+          execute_and_clear(sql, name, binds) {|result| result.cmd_tuples }
+        end
+        alias :exec_update :exec_delete
+
+        def sql_for_insert(sql, pk, id_value, sequence_name, binds)
+          unless pk
+            # Extract the table from the insert sql. Yuck.
+            table_ref = extract_table_ref_from_insert_sql(sql)
+            pk = primary_key(table_ref) if table_ref
+          end
+
+          if pk && use_insert_returning?
+            sql = "#{sql} RETURNING #{quote_column_name(pk)}"
+          end
+
+          [sql, binds]
+        end
+
+        def exec_insert(sql, name, binds, pk = nil, sequence_name = nil)
+          val = exec_query(sql, name, binds)
+          if !use_insert_returning? && pk
+            unless sequence_name
+              table_ref = extract_table_ref_from_insert_sql(sql)
+              sequence_name = default_sequence_name(table_ref, pk)
+              return val unless sequence_name
+            end
+            last_insert_id_result(sequence_name)
+          else
+            val
+          end
+        end
+
+        # Executes an UPDATE query and returns the number of affected tuples.
+        def update_sql(sql, name = nil)
+          super.cmd_tuples
+        end
+
+        # Begins a transaction.
+        def begin_db_transaction
+          execute "BEGIN"
+        end
+
+        def begin_isolated_db_transaction(isolation)
+          begin_db_transaction
+          execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
+        end
+
+        # Commits a transaction.
+        def commit_db_transaction
+          execute "COMMIT"
+        end
+
+        # Aborts a transaction.
+        def rollback_db_transaction
+          execute "ROLLBACK"
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
new file mode 100644
index 0000000000..d28a2b4fa0
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
@@ -0,0 +1,36 @@
+require 'active_record/connection_adapters/postgresql/oid/infinity'
+
+require 'active_record/connection_adapters/postgresql/oid/array'
+require 'active_record/connection_adapters/postgresql/oid/bit'
+require 'active_record/connection_adapters/postgresql/oid/bit_varying'
+require 'active_record/connection_adapters/postgresql/oid/bytea'
+require 'active_record/connection_adapters/postgresql/oid/cidr'
+require 'active_record/connection_adapters/postgresql/oid/date'
+require 'active_record/connection_adapters/postgresql/oid/date_time'
+require 'active_record/connection_adapters/postgresql/oid/decimal'
+require 'active_record/connection_adapters/postgresql/oid/enum'
+require 'active_record/connection_adapters/postgresql/oid/float'
+require 'active_record/connection_adapters/postgresql/oid/hstore'
+require 'active_record/connection_adapters/postgresql/oid/inet'
+require 'active_record/connection_adapters/postgresql/oid/integer'
+require 'active_record/connection_adapters/postgresql/oid/json'
+require 'active_record/connection_adapters/postgresql/oid/jsonb'
+require 'active_record/connection_adapters/postgresql/oid/money'
+require 'active_record/connection_adapters/postgresql/oid/point'
+require 'active_record/connection_adapters/postgresql/oid/range'
+require 'active_record/connection_adapters/postgresql/oid/specialized_string'
+require 'active_record/connection_adapters/postgresql/oid/time'
+require 'active_record/connection_adapters/postgresql/oid/uuid'
+require 'active_record/connection_adapters/postgresql/oid/vector'
+require 'active_record/connection_adapters/postgresql/oid/xml'
+
+require 'active_record/connection_adapters/postgresql/oid/type_map_initializer'
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
new file mode 100644
index 0000000000..cd5efe2bb8
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -0,0 +1,96 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Array < Type::Value # :nodoc:
+          include Type::Mutable
+
+          # Loads pg_array_parser if available. String parsing can be
+          # performed quicker by a native extension, which will not create
+          # a large amount of Ruby objects that will need to be garbage
+          # collected. pg_array_parser has a C and Java extension
+          begin
+            require 'pg_array_parser'
+            include PgArrayParser
+          rescue LoadError
+            require 'active_record/connection_adapters/postgresql/array_parser'
+            include PostgreSQL::ArrayParser
+          end
+
+          attr_reader :subtype, :delimiter
+          delegate :type, to: :subtype
+
+          def initialize(subtype, delimiter = ',')
+            @subtype = subtype
+            @delimiter = delimiter
+          end
+
+          def type_cast_from_database(value)
+            if value.is_a?(::String)
+              type_cast_array(parse_pg_array(value), :type_cast_from_database)
+            else
+              super
+            end
+          end
+
+          def type_cast_from_user(value)
+            type_cast_array(value, :type_cast_from_user)
+          end
+
+          def type_cast_for_database(value)
+            if value.is_a?(::Array)
+              cast_value_for_database(value)
+            else
+              super
+            end
+          end
+
+          private
+
+          def type_cast_array(value, method)
+            if value.is_a?(::Array)
+              value.map { |item| type_cast_array(item, method) }
+            else
+              @subtype.public_send(method, value)
+            end
+          end
+
+          def cast_value_for_database(value)
+            if value.is_a?(::Array)
+              casted_values = value.map { |item| cast_value_for_database(item) }
+              "{#{casted_values.join(delimiter)}}"
+            else
+              quote_and_escape(subtype.type_cast_for_database(value))
+            end
+          end
+
+          ARRAY_ESCAPE = "\\" * 2 * 2 # escape the backslash twice for PG arrays
+
+          def quote_and_escape(value)
+            case value
+            when ::String
+              if string_requires_quoting?(value)
+                value = value.gsub(/\\/, ARRAY_ESCAPE)
+                value.gsub!(/"/,"\\\"")
+                %("#{value}")
+              else
+                value
+              end
+            when nil then "NULL"
+            else value
+            end
+          end
+
+          # See http://www.postgresql.org/docs/9.2/static/arrays.html#ARRAYS-IO
+          # for a list of all cases in which strings will be quoted.
+          def string_requires_quoting?(string)
+            string.empty? ||
+              string == "NULL" ||
+              string =~ /[\{\}"\\\s]/ ||
+              string.include?(delimiter)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit.rb
new file mode 100644
index 0000000000..1dbb40ca1d
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit.rb
@@ -0,0 +1,52 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Bit < Type::Value # :nodoc:
+          def type
+            :bit
+          end
+
+          def type_cast(value)
+            if ::String === value
+              case value
+              when /^0x/i
+                value[2..-1].hex.to_s(2) # Hexadecimal notation
+              else
+                value                    # Bit-string notation
+              end
+            else
+              value
+            end
+          end
+
+          def type_cast_for_database(value)
+            Data.new(super) if value
+          end
+
+          class Data
+            def initialize(value)
+              @value = value
+            end
+
+            def to_s
+              value
+            end
+
+            def binary?
+              /\A[01]*\Z/ === value
+            end
+
+            def hex?
+              /\A[0-9A-F]*\Z/i === value
+            end
+
+            protected
+
+            attr_reader :value
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit_varying.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit_varying.rb
new file mode 100644
index 0000000000..4c21097d48
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bit_varying.rb
@@ -0,0 +1,13 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class BitVarying < OID::Bit # :nodoc:
+          def type
+            :bit_varying
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb
new file mode 100644
index 0000000000..997613d7be
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb
@@ -0,0 +1,14 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Bytea < Type::Binary # :nodoc:
+          def type_cast_from_database(value)
+            return if value.nil?
+            PGconn.unescape_bytea(super)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb
new file mode 100644
index 0000000000..a53b4ee8e2
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb
@@ -0,0 +1,46 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Cidr < Type::Value # :nodoc:
+          def type
+            :cidr
+          end
+
+          def type_cast_for_schema(value)
+            subnet_mask = value.instance_variable_get(:@mask_addr)
+
+            # If the subnet mask is equal to /32, don't output it
+            if subnet_mask == (2**32 - 1)
+              "\"#{value.to_s}\""
+            else
+              "\"#{value.to_s}/#{subnet_mask.to_s(2).count('1')}\""
+            end
+          end
+
+          def type_cast_for_database(value)
+            if IPAddr === value
+              "#{value.to_s}/#{value.instance_variable_get(:@mask_addr).to_s(2).count('1')}"
+            else
+              value
+            end
+          end
+
+          def cast_value(value)
+            if value.nil?
+              nil
+            elsif String === value
+              begin
+                IPAddr.new(value)
+              rescue ArgumentError
+                nil
+              end
+            else
+              value
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/date.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/date.rb
new file mode 100644
index 0000000000..1d8d264530
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/date.rb
@@ -0,0 +1,11 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Date < Type::Date # :nodoc:
+          include Infinity
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb
new file mode 100644
index 0000000000..b9e7894e5c
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb
@@ -0,0 +1,27 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class DateTime < Type::DateTime # :nodoc:
+          include Infinity
+
+          def cast_value(value)
+            if value.is_a?(::String)
+              case value
+              when 'infinity' then ::Float::INFINITY
+              when '-infinity' then -::Float::INFINITY
+              when / BC$/
+                astronomical_year = format("%04d", -value[/^\d+/].to_i + 1)
+                super(value.sub(/ BC$/, "").sub(/^\d+/, astronomical_year))
+              else
+                super
+              end
+            else
+              value
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/decimal.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/decimal.rb
new file mode 100644
index 0000000000..43d22c8daf
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/decimal.rb
@@ -0,0 +1,13 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Decimal < Type::Decimal # :nodoc:
+          def infinity(options = {})
+            BigDecimal.new("Infinity") * (options[:negative] ? -1 : 1)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/enum.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/enum.rb
new file mode 100644
index 0000000000..77d5038efd
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/enum.rb
@@ -0,0 +1,17 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Enum < Type::Value # :nodoc:
+          def type
+            :enum
+          end
+
+          def type_cast(value)
+            value.to_s
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/float.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/float.rb
new file mode 100644
index 0000000000..78ef94b912
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/float.rb
@@ -0,0 +1,21 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Float < Type::Float # :nodoc:
+          include Infinity
+
+          def cast_value(value)
+            case value
+            when ::Float then     value
+            when 'Infinity' then  ::Float::INFINITY
+            when '-Infinity' then -::Float::INFINITY
+            when 'NaN' then       ::Float::NAN
+            else                  value.to_f
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
new file mode 100644
index 0000000000..be4525c94f
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
@@ -0,0 +1,59 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Hstore < Type::Value # :nodoc:
+          include Type::Mutable
+
+          def type
+            :hstore
+          end
+
+          def type_cast_from_database(value)
+            if value.is_a?(::String)
+              ::Hash[value.scan(HstorePair).map { |k, v|
+                v = v.upcase == 'NULL' ? nil : v.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
+                k = k.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
+                [k, v]
+              }]
+            else
+              value
+            end
+          end
+
+          def type_cast_for_database(value)
+            if value.is_a?(::Hash)
+              value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(', ')
+            else
+              value
+            end
+          end
+
+          def accessor
+            ActiveRecord::Store::StringKeyedHashAccessor
+          end
+
+          private
+
+          HstorePair = begin
+            quoted_string = /"[^"\\]*(?:\\.[^"\\]*)*"/
+            unquoted_string = /(?:\\.|[^\s,])[^\s=,\\]*(?:\\.[^\s=,\\]*|=[^,>])*/
+            /(#{quoted_string}|#{unquoted_string})\s*=>\s*(#{quoted_string}|#{unquoted_string})/
+          end
+
+          def escape_hstore(value)
+            if value.nil?
+              'NULL'
+            else
+              if value == ""
+                '""'
+              else
+                '"%s"' % value.to_s.gsub(/(["\\])/, '\\\\\1')
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/inet.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/inet.rb
new file mode 100644
index 0000000000..96486fa65b
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/inet.rb
@@ -0,0 +1,13 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Inet < Cidr # :nodoc:
+          def type
+            :inet
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/infinity.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/infinity.rb
new file mode 100644
index 0000000000..e47780399a
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/infinity.rb
@@ -0,0 +1,13 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        module Infinity # :nodoc:
+          def infinity(options = {})
+            options[:negative] ? -::Float::INFINITY : ::Float::INFINITY
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/integer.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/integer.rb
new file mode 100644
index 0000000000..59abdc0009
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/integer.rb
@@ -0,0 +1,11 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Integer < Type::Integer # :nodoc:
+          include Infinity
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/json.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/json.rb
new file mode 100644
index 0000000000..e12ddd9901
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/json.rb
@@ -0,0 +1,35 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Json < Type::Value # :nodoc:
+          include Type::Mutable
+
+          def type
+            :json
+          end
+
+          def type_cast_from_database(value)
+            if value.is_a?(::String)
+              ::ActiveSupport::JSON.decode(value)
+            else
+              super
+            end
+          end
+
+          def type_cast_for_database(value)
+            if value.is_a?(::Array) || value.is_a?(::Hash)
+              ::ActiveSupport::JSON.encode(value)
+            else
+              super
+            end
+          end
+
+          def accessor
+            ActiveRecord::Store::StringKeyedHashAccessor
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/jsonb.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/jsonb.rb
new file mode 100644
index 0000000000..34ed32ad35
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/jsonb.rb
@@ -0,0 +1,23 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Jsonb < Json # :nodoc:
+          def type
+            :jsonb
+          end
+
+          def changed_in_place?(raw_old_value, new_value)
+            # Postgres does not preserve insignificant whitespaces when
+            # roundtripping jsonb columns. This causes some false positives for
+            # the comparison here. Therefore, we need to parse and re-dump the
+            # raw value here to ensure the insignificant whitespaces are
+            # consitent with our encoder's output.
+            raw_old_value = type_cast_for_database(type_cast_from_database(raw_old_value))
+            super(raw_old_value, new_value)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb
new file mode 100644
index 0000000000..df890c2ed6
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb
@@ -0,0 +1,43 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Money < Type::Decimal # :nodoc:
+          include Infinity
+
+          class_attribute :precision
+
+          def type
+            :money
+          end
+
+          def scale
+            2
+          end
+
+          def cast_value(value)
+            return value unless ::String === value
+
+            # Because money output is formatted according to the locale, there are two
+            # cases to consider (note the decimal separators):
+            #  (1) $12,345,678.12
+            #  (2) $12.345.678,12
+            # Negative values are represented as follows:
+            #  (3) -$2.55
+            #  (4) ($2.55)
+
+            value.sub!(/^\((.+)\)$/, '-\1') # (4)
+            case value
+            when /^-?\D+[\d,]+\.\d{2}$/  # (1)
+              value.gsub!(/[^-\d.]/, '')
+            when /^-?\D+[\d.]+,\d{2}$/  # (2)
+              value.gsub!(/[^-\d,]/, '').sub!(/,/, '.')
+            end
+
+            super(value)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb
new file mode 100644
index 0000000000..bac8b01d6b
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb
@@ -0,0 +1,43 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Point < Type::Value # :nodoc:
+          include Type::Mutable
+
+          def type
+            :point
+          end
+
+          def type_cast(value)
+            case value
+            when ::String
+              if value[0] == '(' && value[-1] == ')'
+                value = value[1...-1]
+              end
+              type_cast(value.split(','))
+            when ::Array
+              value.map { |v| Float(v) }
+            else
+              value
+            end
+          end
+
+          def type_cast_for_database(value)
+            if value.is_a?(::Array)
+              "(#{number_for_point(value[0])},#{number_for_point(value[1])})"
+            else
+              super
+            end
+          end
+
+          private
+
+          def number_for_point(number)
+            number.to_s.gsub(/\.0$/, '')
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
new file mode 100644
index 0000000000..ae967d5167
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
@@ -0,0 +1,76 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Range < Type::Value # :nodoc:
+          attr_reader :subtype, :type
+
+          def initialize(subtype, type)
+            @subtype = subtype
+            @type = type
+          end
+
+          def type_cast_for_schema(value)
+            value.inspect.gsub('Infinity', '::Float::INFINITY')
+          end
+
+          def cast_value(value)
+            return if value == 'empty'
+            return value if value.is_a?(::Range)
+
+            extracted = extract_bounds(value)
+            from = type_cast_single extracted[:from]
+            to = type_cast_single extracted[:to]
+
+            if !infinity?(from) && extracted[:exclude_start]
+              if from.respond_to?(:succ)
+                from = from.succ
+                ActiveSupport::Deprecation.warn <<-MESSAGE
+Excluding the beginning of a Range is only partialy supported through `#succ`.
+This is not reliable and will be removed in the future.
+                MESSAGE
+              else
+                raise ArgumentError, "The Ruby Range object does not support excluding the beginning of a Range. (unsupported value: '#{value}')"
+              end
+            end
+            ::Range.new(from, to, extracted[:exclude_end])
+          end
+
+          def type_cast_for_database(value)
+            if value.is_a?(::Range)
+              from = type_cast_single_for_database(value.begin)
+              to = type_cast_single_for_database(value.end)
+              "[#{from},#{to}#{value.exclude_end? ? ')' : ']'}"
+            else
+              super
+            end
+          end
+
+          private
+
+          def type_cast_single(value)
+            infinity?(value) ? value : @subtype.type_cast_from_database(value)
+          end
+
+          def type_cast_single_for_database(value)
+            infinity?(value) ? '' : @subtype.type_cast_for_database(value)
+          end
+
+          def extract_bounds(value)
+            from, to = value[1..-2].split(',')
+            {
+              from:          (value[1] == ',' || from == '-infinity') ? @subtype.infinity(negative: true) : from,
+              to:            (value[-2] == ',' || to == 'infinity') ? @subtype.infinity : to,
+              exclude_start: (value[0] == '('),
+              exclude_end:   (value[-1] == ')')
+            }
+          end
+
+          def infinity?(value)
+            value.respond_to?(:infinite?) && value.infinite?
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/specialized_string.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/specialized_string.rb
new file mode 100644
index 0000000000..2d2fede4e8
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/specialized_string.rb
@@ -0,0 +1,15 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class SpecializedString < Type::String # :nodoc:
+          attr_reader :type
+
+          def initialize(type)
+            @type = type
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/time.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/time.rb
new file mode 100644
index 0000000000..8f0246eddb
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/time.rb
@@ -0,0 +1,11 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Time < Type::Time # :nodoc:
+          include Infinity
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
new file mode 100644
index 0000000000..e396ff4a1e
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
@@ -0,0 +1,85 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        # This class uses the data from PostgreSQL pg_type table to build
+        # the OID -> Type mapping.
+        #   - OID is and integer representing the type.
+        #   - Type is an OID::Type object.
+        # This class has side effects on the +store+ passed during initialization.
+        class TypeMapInitializer # :nodoc:
+          def initialize(store)
+            @store = store
+          end
+
+          def run(records)
+            nodes = records.reject { |row| @store.key? row['oid'].to_i }
+            mapped, nodes = nodes.partition { |row| @store.key? row['typname'] }
+            ranges, nodes = nodes.partition { |row| row['typtype'] == 'r' }
+            enums, nodes = nodes.partition { |row| row['typtype'] == 'e' }
+            domains, nodes = nodes.partition { |row| row['typtype'] == 'd' }
+            arrays, nodes = nodes.partition { |row| row['typinput'] == 'array_in' }
+            composites, nodes = nodes.partition { |row| row['typelem'] != '0' }
+
+            mapped.each     { |row| register_mapped_type(row)    }
+            enums.each      { |row| register_enum_type(row)      }
+            domains.each    { |row| register_domain_type(row)    }
+            arrays.each     { |row| register_array_type(row)     }
+            ranges.each     { |row| register_range_type(row)     }
+            composites.each { |row| register_composite_type(row) }
+          end
+
+          private
+          def register_mapped_type(row)
+            alias_type row['oid'], row['typname']
+          end
+
+          def register_enum_type(row)
+            register row['oid'], OID::Enum.new
+          end
+
+          def register_array_type(row)
+            if subtype = @store.lookup(row['typelem'].to_i)
+              register row['oid'], OID::Array.new(subtype, row['typdelim'])
+            end
+          end
+
+          def register_range_type(row)
+            if subtype = @store.lookup(row['rngsubtype'].to_i)
+              register row['oid'], OID::Range.new(subtype, row['typname'].to_sym)
+            end
+          end
+
+          def register_domain_type(row)
+            if base_type = @store.lookup(row["typbasetype"].to_i)
+              register row['oid'], base_type
+            else
+              warn "unknown base type (OID: #{row["typbasetype"]}) for domain #{row["typname"]}."
+            end
+          end
+
+          def register_composite_type(row)
+            if subtype = @store.lookup(row['typelem'].to_i)
+              register row['oid'], OID::Vector.new(row['typdelim'], subtype)
+            end
+          end
+
+          def register(oid, oid_type)
+            oid = assert_valid_registration(oid, oid_type)
+            @store.register_type(oid, oid_type)
+          end
+
+          def alias_type(oid, target)
+            oid = assert_valid_registration(oid, target)
+            @store.alias_type(oid, target)
+          end
+
+          def assert_valid_registration(oid, oid_type)
+            raise ArgumentError, "can't register nil type for OID #{oid}" if oid_type.nil?
+            oid.to_i
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
new file mode 100644
index 0000000000..dd97393eac
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
@@ -0,0 +1,26 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Uuid < Type::Value # :nodoc:
+          RFC_4122 = %r{\A\{?[a-fA-F0-9]{4}-?
+                             [a-fA-F0-9]{4}-?
+                             [a-fA-F0-9]{4}-?
+                             [1-5][a-fA-F0-9]{3}-?
+                             [8-Bab][a-fA-F0-9]{3}-?
+                             [a-fA-F0-9]{4}-?
+                             [a-fA-F0-9]{4}-?
+                             [a-fA-F0-9]{4}-?\}?\z}x
+
+          def type
+            :uuid
+          end
+
+          def type_cast(value)
+            value.to_s[RFC_4122, 0]
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/vector.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/vector.rb
new file mode 100644
index 0000000000..de4187b028
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/vector.rb
@@ -0,0 +1,26 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Vector < Type::Value # :nodoc:
+          attr_reader :delim, :subtype
+
+          # +delim+ corresponds to the `typdelim` column in the pg_types
+          # table.  +subtype+ is derived from the `typelem` column in the
+          # pg_types table.
+          def initialize(delim, subtype)
+            @delim   = delim
+            @subtype = subtype
+          end
+
+          # FIXME: this should probably split on +delim+ and use +subtype+
+          # to cast the values.  Unfortunately, the current Rails behavior
+          # is to just return the string.
+          def type_cast(value)
+            value
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/xml.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/xml.rb
new file mode 100644
index 0000000000..334af7c598
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/xml.rb
@@ -0,0 +1,28 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Xml < Type::String # :nodoc:
+          def type
+            :xml
+          end
+
+          def type_cast_for_database(value)
+            return unless value
+            Data.new(super)
+          end
+
+          class Data # :nodoc:
+            def initialize(value)
+              @value = value
+            end
+
+            def to_s
+              @value
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
new file mode 100644
index 0000000000..cf5c8d288e
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
@@ -0,0 +1,118 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module Quoting
+        # Escapes binary strings for bytea input to the database.
+        def escape_bytea(value)
+          @connection.escape_bytea(value) if value
+        end
+
+        # Unescapes bytea output from a database to the binary string it represents.
+        # NOTE: This is NOT an inverse of escape_bytea! This is only to be used
+        # on escaped binary output from database drive.
+        def unescape_bytea(value)
+          @connection.unescape_bytea(value) if value
+        end
+
+        # Quotes PostgreSQL-specific data types for SQL input.
+        def quote(value, column = nil) #:nodoc:
+          return super unless column
+
+          case value
+          when Float
+            if value.infinite? || value.nan?
+              "'#{value.to_s}'"
+            else
+              super
+            end
+          else
+            super
+          end
+        end
+
+        # Quotes strings for use in SQL input.
+        def quote_string(s) #:nodoc:
+          @connection.escape(s)
+        end
+
+        # Checks the following cases:
+        #
+        # - table_name
+        # - "table.name"
+        # - schema_name.table_name
+        # - schema_name."table.name"
+        # - "schema.name".table_name
+        # - "schema.name"."table.name"
+        def quote_table_name(name)
+          Utils.extract_schema_qualified_name(name.to_s).quoted
+        end
+
+        def quote_table_name_for_assignment(table, attr)
+          quote_column_name(attr)
+        end
+
+        # Quotes column names for use in SQL queries.
+        def quote_column_name(name) #:nodoc:
+          PGconn.quote_ident(name.to_s)
+        end
+
+        # Quote date/time values for use in SQL input. Includes microseconds
+        # if the value is a Time responding to usec.
+        def quoted_date(value) #:nodoc:
+          result = super
+          if value.acts_like?(:time) && value.respond_to?(:usec)
+            result = "#{result}.#{sprintf("%06d", value.usec)}"
+          end
+
+          if value.year <= 0
+            bce_year = format("%04d", -value.year + 1)
+            result = result.sub(/^-?\d+/, bce_year) + " BC"
+          end
+          result
+        end
+
+        # Does not quote function default values for UUID columns
+        def quote_default_value(value, column) #:nodoc:
+          if column.type == :uuid && value =~ /\(\)/
+            value
+          else
+            quote(value, column)
+          end
+        end
+
+        private
+
+        def _quote(value)
+          case value
+          when Type::Binary::Data
+            "'#{escape_bytea(value.to_s)}'"
+          when OID::Xml::Data
+            "xml '#{quote_string(value.to_s)}'"
+          when OID::Bit::Data
+            if value.binary?
+              "B'#{value}'"
+            elsif value.hex?
+              "X'#{value}'"
+            end
+          else
+            super
+          end
+        end
+
+        def _type_cast(value)
+          case value
+          when Type::Binary::Data
+            # Return a bind param hash with format as binary.
+            # See http://deveiate.org/code/pg/PGconn.html#method-i-exec_prepared-doc
+            # for more information
+            { value: value.to_s, format: 1 }
+          when OID::Xml::Data, OID::Bit::Data
+            value.to_s
+          else
+            super
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/referential_integrity.rb b/activerecord/lib/active_record/connection_adapters/postgresql/referential_integrity.rb
new file mode 100644
index 0000000000..52b307c432
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/referential_integrity.rb
@@ -0,0 +1,30 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module ReferentialIntegrity # :nodoc:
+        def supports_disable_referential_integrity? # :nodoc:
+          true
+        end
+
+        def disable_referential_integrity # :nodoc:
+          if supports_disable_referential_integrity?
+            begin
+              execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} DISABLE TRIGGER ALL" }.join(";"))
+            rescue
+              execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} DISABLE TRIGGER USER" }.join(";"))
+            end
+          end
+          yield
+        ensure
+          if supports_disable_referential_integrity?
+            begin
+              execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} ENABLE TRIGGER ALL" }.join(";"))
+            rescue
+              execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} ENABLE TRIGGER USER" }.join(";"))
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
new file mode 100644
index 0000000000..83554bbf74
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
@@ -0,0 +1,154 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module ColumnMethods
+        def xml(*args)
+          options = args.extract_options!
+          column(args[0], :xml, options)
+        end
+
+        def tsvector(*args)
+          options = args.extract_options!
+          column(args[0], :tsvector, options)
+        end
+
+        def int4range(name, options = {})
+          column(name, :int4range, options)
+        end
+
+        def int8range(name, options = {})
+          column(name, :int8range, options)
+        end
+
+        def tsrange(name, options = {})
+          column(name, :tsrange, options)
+        end
+
+        def tstzrange(name, options = {})
+          column(name, :tstzrange, options)
+        end
+
+        def numrange(name, options = {})
+          column(name, :numrange, options)
+        end
+
+        def daterange(name, options = {})
+          column(name, :daterange, options)
+        end
+
+        def hstore(name, options = {})
+          column(name, :hstore, options)
+        end
+
+        def ltree(name, options = {})
+          column(name, :ltree, options)
+        end
+
+        def inet(name, options = {})
+          column(name, :inet, options)
+        end
+
+        def cidr(name, options = {})
+          column(name, :cidr, options)
+        end
+
+        def macaddr(name, options = {})
+          column(name, :macaddr, options)
+        end
+
+        def uuid(name, options = {})
+          column(name, :uuid, options)
+        end
+
+        def json(name, options = {})
+          column(name, :json, options)
+        end
+
+        def jsonb(name, options = {})
+          column(name, :jsonb, options)
+        end
+
+        def citext(name, options = {})
+          column(name, :citext, options)
+        end
+
+        def point(name, options = {})
+          column(name, :point, options)
+        end
+
+        def bit(name, options)
+          column(name, :bit, options)
+        end
+
+        def bit_varying(name, options)
+          column(name, :bit_varying, options)
+        end
+
+        def money(name, options)
+          column(name, :money, options)
+        end
+      end
+
+      class ColumnDefinition < ActiveRecord::ConnectionAdapters::ColumnDefinition
+        attr_accessor :array
+      end
+
+      class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
+        include ColumnMethods
+
+        # Defines the primary key field.
+        # Use of the native PostgreSQL UUID type is supported, and can be used
+        # by defining your tables as such:
+        #
+        #   create_table :stuffs, id: :uuid do |t|
+        #     t.string :content
+        #     t.timestamps
+        #   end
+        #
+        # By default, this will use the +uuid_generate_v4()+ function from the
+        # +uuid-ossp+ extension, which MUST be enabled on your database. To enable
+        # the +uuid-ossp+ extension, you can use the +enable_extension+ method in your
+        # migrations. To use a UUID primary key without +uuid-ossp+ enabled, you can
+        # set the +:default+ option to +nil+:
+        #
+        #   create_table :stuffs, id: false do |t|
+        #     t.primary_key :id, :uuid, default: nil
+        #     t.uuid :foo_id
+        #     t.timestamps
+        #   end
+        #
+        # You may also pass a different UUID generation function from +uuid-ossp+
+        # or another library.
+        #
+        # Note that setting the UUID primary key default value to +nil+ will
+        # require you to assure that you always provide a UUID value before saving
+        # a record (as primary keys cannot be +nil+). This might be done via the
+        # +SecureRandom.uuid+ method and a +before_save+ callback, for instance.
+        def primary_key(name, type = :primary_key, options = {})
+          return super unless type == :uuid
+          options[:default] = options.fetch(:default, 'uuid_generate_v4()')
+          options[:primary_key] = true
+          column name, type, options
+        end
+
+        def column(name, type = nil, options = {})
+          super
+          column = self[name]
+          column.array = options[:array]
+
+          self
+        end
+
+        private
+
+          def create_column_definition(name, type)
+            PostgreSQL::ColumnDefinition.new name, type
+          end
+      end
+
+      class Table < ActiveRecord::ConnectionAdapters::Table
+        include ColumnMethods
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
new file mode 100644
index 0000000000..7042817672
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -0,0 +1,560 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      class SchemaCreation < AbstractAdapter::SchemaCreation
+        private
+
+        def visit_AddColumn(o)
+          sql_type = type_to_sql(o.type, o.limit, o.precision, o.scale)
+          sql = "ADD COLUMN #{quote_column_name(o.name)} #{sql_type}"
+          add_column_options!(sql, column_options(o))
+        end
+
+        def visit_ColumnDefinition(o)
+          sql = super
+          if o.primary_key? && o.type != :primary_key
+            sql << " PRIMARY KEY "
+            add_column_options!(sql, column_options(o))
+          end
+          sql
+        end
+
+        def add_column_options!(sql, options)
+          if options[:array] || options[:column].try(:array)
+            sql << '[]'
+          end
+
+          column = options.fetch(:column) { return super }
+          if column.type == :uuid && options[:default] =~ /\(\)/
+            sql << " DEFAULT #{options[:default]}"
+          else
+            super
+          end
+        end
+
+        def type_for_column(column)
+          if column.array
+            @conn.lookup_cast_type("#{column.sql_type}[]")
+          else
+            super
+          end
+        end
+      end
+
+      module SchemaStatements
+        # Drops the database specified on the +name+ attribute
+        # and creates it again using the provided +options+.
+        def recreate_database(name, options = {}) #:nodoc:
+          drop_database(name)
+          create_database(name, options)
+        end
+
+        # Create a new PostgreSQL database. Options include <tt>:owner</tt>, <tt>:template</tt>,
+        # <tt>:encoding</tt> (defaults to utf8), <tt>:collation</tt>, <tt>:ctype</tt>,
+        # <tt>:tablespace</tt>, and <tt>:connection_limit</tt> (note that MySQL uses
+        # <tt>:charset</tt> while PostgreSQL uses <tt>:encoding</tt>).
+        #
+        # Example:
+        #   create_database config[:database], config
+        #   create_database 'foo_development', encoding: 'unicode'
+        def create_database(name, options = {})
+          options = { encoding: 'utf8' }.merge!(options.symbolize_keys)
+
+          option_string = options.sum do |key, value|
+            case key
+            when :owner
+              " OWNER = \"#{value}\""
+            when :template
+              " TEMPLATE = \"#{value}\""
+            when :encoding
+              " ENCODING = '#{value}'"
+            when :collation
+              " LC_COLLATE = '#{value}'"
+            when :ctype
+              " LC_CTYPE = '#{value}'"
+            when :tablespace
+              " TABLESPACE = \"#{value}\""
+            when :connection_limit
+              " CONNECTION LIMIT = #{value}"
+            else
+              ""
+            end
+          end
+
+          execute "CREATE DATABASE #{quote_table_name(name)}#{option_string}"
+        end
+
+        # Drops a PostgreSQL database.
+        #
+        # Example:
+        #   drop_database 'matt_development'
+        def drop_database(name) #:nodoc:
+          execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
+        end
+
+        # Returns the list of all tables in the schema search path or a specified schema.
+        def tables(name = nil)
+          query(<<-SQL, 'SCHEMA').map { |row| row[0] }
+            SELECT tablename
+            FROM pg_tables
+            WHERE schemaname = ANY (current_schemas(false))
+          SQL
+        end
+
+        # Returns true if table exists.
+        # If the schema is not specified as part of +name+ then it will only find tables within
+        # the current schema search path (regardless of permissions to access tables in other schemas)
+        def table_exists?(name)
+          name = Utils.extract_schema_qualified_name(name.to_s)
+          return false unless name.identifier
+
+          exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0
+              SELECT COUNT(*)
+              FROM pg_class c
+              LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
+              WHERE c.relkind IN ('r','v','m') -- (r)elation/table, (v)iew, (m)aterialized view
+              AND c.relname = '#{name.identifier}'
+              AND n.nspname = #{name.schema ? "'#{name.schema}'" : 'ANY (current_schemas(false))'}
+          SQL
+        end
+
+        # Returns true if schema exists.
+        def schema_exists?(name)
+          exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0
+            SELECT COUNT(*)
+            FROM pg_namespace
+            WHERE nspname = '#{name}'
+          SQL
+        end
+
+        def index_name_exists?(table_name, index_name, default)
+          exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0
+            SELECT COUNT(*)
+            FROM pg_class t
+            INNER JOIN pg_index d ON t.oid = d.indrelid
+            INNER JOIN pg_class i ON d.indexrelid = i.oid
+            WHERE i.relkind = 'i'
+              AND i.relname = '#{index_name}'
+              AND t.relname = '#{table_name}'
+              AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) )
+          SQL
+        end
+
+        # Returns an array of indexes for the given table.
+        def indexes(table_name, name = nil)
+           result = query(<<-SQL, 'SCHEMA')
+             SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid
+             FROM pg_class t
+             INNER JOIN pg_index d ON t.oid = d.indrelid
+             INNER JOIN pg_class i ON d.indexrelid = i.oid
+             WHERE i.relkind = 'i'
+               AND d.indisprimary = 'f'
+               AND t.relname = '#{table_name}'
+               AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) )
+            ORDER BY i.relname
+          SQL
+
+          result.map do |row|
+            index_name = row[0]
+            unique = row[1] == 't'
+            indkey = row[2].split(" ")
+            inddef = row[3]
+            oid = row[4]
+
+            columns = Hash[query(<<-SQL, "SCHEMA")]
+            SELECT a.attnum, a.attname
+            FROM pg_attribute a
+            WHERE a.attrelid = #{oid}
+            AND a.attnum IN (#{indkey.join(",")})
+            SQL
+
+            column_names = columns.values_at(*indkey).compact
+
+            unless column_names.empty?
+              # add info on sort order for columns (only desc order is explicitly specified, asc is the default)
+              desc_order_columns = inddef.scan(/(\w+) DESC/).flatten
+              orders = desc_order_columns.any? ? Hash[desc_order_columns.map {|order_column| [order_column, :desc]}] : {}
+              where = inddef.scan(/WHERE (.+)$/).flatten[0]
+              using = inddef.scan(/USING (.+?) /).flatten[0].to_sym
+
+              IndexDefinition.new(table_name, index_name, unique, column_names, [], orders, where, nil, using)
+            end
+          end.compact
+        end
+
+        # Returns the list of all column definitions for a table.
+        def columns(table_name)
+          # Limit, precision, and scale are all handled by the superclass.
+          column_definitions(table_name).map do |column_name, type, default, notnull, oid, fmod|
+            oid = get_oid_type(oid.to_i, fmod.to_i, column_name, type)
+            default_value = extract_value_from_default(oid, default)
+            default_function = extract_default_function(default_value, default)
+            new_column(column_name, default_value, oid, type, notnull == 'f', default_function)
+          end
+        end
+
+        def new_column(name, default, cast_type, sql_type = nil, null = true, default_function = nil) # :nodoc:
+          PostgreSQLColumn.new(name, default, cast_type, sql_type, null, default_function)
+        end
+
+        # Returns the current database name.
+        def current_database
+          query('select current_database()', 'SCHEMA')[0][0]
+        end
+
+        # Returns the current schema name.
+        def current_schema
+          query('SELECT current_schema', 'SCHEMA')[0][0]
+        end
+
+        # Returns the current database encoding format.
+        def encoding
+          query(<<-end_sql, 'SCHEMA')[0][0]
+            SELECT pg_encoding_to_char(pg_database.encoding) FROM pg_database
+            WHERE pg_database.datname LIKE '#{current_database}'
+          end_sql
+        end
+
+        # Returns the current database collation.
+        def collation
+          query(<<-end_sql, 'SCHEMA')[0][0]
+            SELECT pg_database.datcollate FROM pg_database WHERE pg_database.datname LIKE '#{current_database}'
+          end_sql
+        end
+
+        # Returns the current database ctype.
+        def ctype
+          query(<<-end_sql, 'SCHEMA')[0][0]
+            SELECT pg_database.datctype FROM pg_database WHERE pg_database.datname LIKE '#{current_database}'
+          end_sql
+        end
+
+        # Returns an array of schema names.
+        def schema_names
+          query(<<-SQL, 'SCHEMA').flatten
+            SELECT nspname
+              FROM pg_namespace
+             WHERE nspname !~ '^pg_.*'
+               AND nspname NOT IN ('information_schema')
+             ORDER by nspname;
+          SQL
+        end
+
+        # Creates a schema for the given schema name.
+        def create_schema schema_name
+          execute "CREATE SCHEMA #{schema_name}"
+        end
+
+        # Drops the schema for the given schema name.
+        def drop_schema schema_name
+          execute "DROP SCHEMA #{schema_name} CASCADE"
+        end
+
+        # Sets the schema search path to a string of comma-separated schema names.
+        # Names beginning with $ have to be quoted (e.g. $user => '$user').
+        # See: http://www.postgresql.org/docs/current/static/ddl-schemas.html
+        #
+        # This should be not be called manually but set in database.yml.
+        def schema_search_path=(schema_csv)
+          if schema_csv
+            execute("SET search_path TO #{schema_csv}", 'SCHEMA')
+            @schema_search_path = schema_csv
+          end
+        end
+
+        # Returns the active schema search path.
+        def schema_search_path
+          @schema_search_path ||= query('SHOW search_path', 'SCHEMA')[0][0]
+        end
+
+        # Returns the current client message level.
+        def client_min_messages
+          query('SHOW client_min_messages', 'SCHEMA')[0][0]
+        end
+
+        # Set the client message level.
+        def client_min_messages=(level)
+          execute("SET client_min_messages TO '#{level}'", 'SCHEMA')
+        end
+
+        # Returns the sequence name for a table's primary key or some other specified key.
+        def default_sequence_name(table_name, pk = nil) #:nodoc:
+          result = serial_sequence(table_name, pk || 'id')
+          return nil unless result
+          Utils.extract_schema_qualified_name(result)
+        rescue ActiveRecord::StatementInvalid
+          PostgreSQL::Name.new(nil, "#{table_name}_#{pk || 'id'}_seq")
+        end
+
+        def serial_sequence(table, column)
+          result = exec_query(<<-eosql, 'SCHEMA')
+            SELECT pg_get_serial_sequence('#{table}', '#{column}')
+          eosql
+          result.rows.first.first
+        end
+
+        # Resets the sequence of a table's primary key to the maximum value.
+        def reset_pk_sequence!(table, pk = nil, sequence = nil) #:nodoc:
+          unless pk and sequence
+            default_pk, default_sequence = pk_and_sequence_for(table)
+
+            pk ||= default_pk
+            sequence ||= default_sequence
+          end
+
+          if @logger && pk && !sequence
+            @logger.warn "#{table} has primary key #{pk} with no default sequence"
+          end
+
+          if pk && sequence
+            quoted_sequence = quote_table_name(sequence)
+
+            select_value <<-end_sql, 'SCHEMA'
+              SELECT setval('#{quoted_sequence}', (SELECT COALESCE(MAX(#{quote_column_name pk})+(SELECT increment_by FROM #{quoted_sequence}), (SELECT min_value FROM #{quoted_sequence})) FROM #{quote_table_name(table)}), false)
+            end_sql
+          end
+        end
+
+        # Returns a table's primary key and belonging sequence.
+        def pk_and_sequence_for(table) #:nodoc:
+          # First try looking for a sequence with a dependency on the
+          # given table's primary key.
+          result = query(<<-end_sql, 'SCHEMA')[0]
+            SELECT attr.attname, nsp.nspname, seq.relname
+            FROM pg_class      seq,
+                 pg_attribute  attr,
+                 pg_depend     dep,
+                 pg_constraint cons,
+                 pg_namespace  nsp
+            WHERE seq.oid           = dep.objid
+              AND seq.relkind       = 'S'
+              AND attr.attrelid     = dep.refobjid
+              AND attr.attnum       = dep.refobjsubid
+              AND attr.attrelid     = cons.conrelid
+              AND attr.attnum       = cons.conkey[1]
+              AND seq.relnamespace  = nsp.oid
+              AND cons.contype      = 'p'
+              AND dep.classid       = 'pg_class'::regclass
+              AND dep.refobjid      = '#{quote_table_name(table)}'::regclass
+          end_sql
+
+          if result.nil? or result.empty?
+            result = query(<<-end_sql, 'SCHEMA')[0]
+              SELECT attr.attname, nsp.nspname,
+                CASE
+                  WHEN pg_get_expr(def.adbin, def.adrelid) !~* 'nextval' THEN NULL
+                  WHEN split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2) ~ '.' THEN
+                    substr(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2),
+                           strpos(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), '.')+1)
+                  ELSE split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2)
+                END
+              FROM pg_class       t
+              JOIN pg_attribute   attr ON (t.oid = attrelid)
+              JOIN pg_attrdef     def  ON (adrelid = attrelid AND adnum = attnum)
+              JOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])
+              JOIN pg_namespace   nsp  ON (t.relnamespace = nsp.oid)
+              WHERE t.oid = '#{quote_table_name(table)}'::regclass
+                AND cons.contype = 'p'
+                AND pg_get_expr(def.adbin, def.adrelid) ~* 'nextval|uuid_generate'
+            end_sql
+          end
+
+          pk = result.shift
+          if result.last
+            [pk, PostgreSQL::Name.new(*result)]
+          else
+            [pk, nil]
+          end
+        rescue
+          nil
+        end
+
+        # Returns just a table's primary key
+        def primary_key(table)
+          row = exec_query(<<-end_sql, 'SCHEMA').rows.first
+            SELECT attr.attname
+            FROM pg_attribute attr
+            INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1]
+            WHERE cons.contype = 'p'
+              AND cons.conrelid = '#{quote_table_name(table)}'::regclass
+          end_sql
+
+          row && row.first
+        end
+
+        # Renames a table.
+        # Also renames a table's primary key sequence if the sequence name exists and
+        # matches the Active Record default.
+        #
+        # Example:
+        #   rename_table('octopuses', 'octopi')
+        def rename_table(table_name, new_name)
+          clear_cache!
+          execute "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
+          pk, seq = pk_and_sequence_for(new_name)
+          if seq && seq.identifier == "#{table_name}_#{pk}_seq"
+            new_seq = "#{new_name}_#{pk}_seq"
+            execute "ALTER TABLE #{quote_table_name(seq)} RENAME TO #{quote_table_name(new_seq)}"
+          end
+
+          rename_table_indexes(table_name, new_name)
+        end
+
+        # Adds a new column to the named table.
+        # See TableDefinition#column for details of the options you can use.
+        def add_column(table_name, column_name, type, options = {})
+          clear_cache!
+          super
+        end
+
+        # Changes the column of a table.
+        def change_column(table_name, column_name, type, options = {})
+          clear_cache!
+          quoted_table_name = quote_table_name(table_name)
+          sql_type = type_to_sql(type, options[:limit], options[:precision], options[:scale])
+          sql_type << "[]" if options[:array]
+          execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{sql_type}"
+
+          change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
+          change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
+        end
+
+        # Changes the default value of a table column.
+        def change_column_default(table_name, column_name, default)
+          clear_cache!
+          column = column_for(table_name, column_name)
+          return unless column
+
+          alter_column_query = "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} %s"
+          if default.nil?
+            # <tt>DEFAULT NULL</tt> results in the same behavior as <tt>DROP DEFAULT</tt>. However, PostgreSQL will
+            # cast the default to the columns type, which leaves us with a default like "default NULL::character varying".
+            execute alter_column_query % "DROP DEFAULT"
+          else
+            execute alter_column_query % "SET DEFAULT #{quote_default_value(default, column)}"
+          end
+        end
+
+        def change_column_null(table_name, column_name, null, default = nil)
+          clear_cache!
+          unless null || default.nil?
+            column = column_for(table_name, column_name)
+            execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote_default_value(default, column)} WHERE #{quote_column_name(column_name)} IS NULL") if column
+          end
+          execute("ALTER TABLE #{quote_table_name(table_name)} ALTER #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL")
+        end
+
+        # Renames a column in a table.
+        def rename_column(table_name, column_name, new_column_name)
+          clear_cache!
+          execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
+          rename_column_indexes(table_name, column_name, new_column_name)
+        end
+
+        def add_index(table_name, column_name, options = {}) #:nodoc:
+          index_name, index_type, index_columns, index_options, index_algorithm, index_using = add_index_options(table_name, column_name, options)
+          execute "CREATE #{index_type} INDEX #{index_algorithm} #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} #{index_using} (#{index_columns})#{index_options}"
+        end
+
+        def remove_index!(table_name, index_name) #:nodoc:
+          execute "DROP INDEX #{quote_table_name(index_name)}"
+        end
+
+        def rename_index(table_name, old_name, new_name)
+          execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
+        end
+
+        def foreign_keys(table_name)
+          fk_info = select_all <<-SQL.strip_heredoc
+            SELECT t2.relname AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete
+            FROM pg_constraint c
+            JOIN pg_class t1 ON c.conrelid = t1.oid
+            JOIN pg_class t2 ON c.confrelid = t2.oid
+            JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
+            JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
+            JOIN pg_namespace t3 ON c.connamespace = t3.oid
+            WHERE c.contype = 'f'
+              AND t1.relname = #{quote(table_name)}
+              AND t3.nspname = ANY (current_schemas(false))
+            ORDER BY c.conname
+          SQL
+
+          fk_info.map do |row|
+            options = {
+              column: row['column'],
+              name: row['name'],
+              primary_key: row['primary_key']
+            }
+
+            options[:on_delete] = extract_foreign_key_action(row['on_delete'])
+            options[:on_update] = extract_foreign_key_action(row['on_update'])
+            ForeignKeyDefinition.new(table_name, row['to_table'], options)
+          end
+        end
+
+        def extract_foreign_key_action(specifier) # :nodoc:
+          case specifier
+          when 'c'; :cascade
+          when 'n'; :nullify
+          when 'r'; :restrict
+          end
+        end
+
+        def index_name_length
+          63
+        end
+
+        # Maps logical Rails types to PostgreSQL-specific data types.
+        def type_to_sql(type, limit = nil, precision = nil, scale = nil)
+          case type.to_s
+          when 'binary'
+            # PostgreSQL doesn't support limits on binary (bytea) columns.
+            # The hard limit is 1Gb, because of a 32-bit size field, and TOAST.
+            case limit
+            when nil, 0..0x3fffffff; super(type)
+            else raise(ActiveRecordError, "No binary type has byte size #{limit}.")
+            end
+          when 'text'
+            # PostgreSQL doesn't support limits on text columns.
+            # The hard limit is 1Gb, according to section 8.3 in the manual.
+            case limit
+            when nil, 0..0x3fffffff; super(type)
+            else raise(ActiveRecordError, "The limit on text can be at most 1GB - 1byte.")
+            end
+          when 'integer'
+            return 'integer' unless limit
+
+            case limit
+              when 1, 2; 'smallint'
+              when 3, 4; 'integer'
+              when 5..8; 'bigint'
+              else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with precision 0 instead.")
+            end
+          when 'datetime'
+            return super unless precision
+
+            case precision
+              when 0..6; "timestamp(#{precision})"
+              else raise(ActiveRecordError, "No timestamp type has precision of #{precision}. The allowed range of precision is from 0 to 6")
+            end
+          else
+            super
+          end
+        end
+
+        # PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and
+        # requires that the ORDER BY include the distinct column.
+        def columns_for_distinct(columns, orders) #:nodoc:
+          order_columns = orders.reject(&:blank?).map{ |s|
+              # Convert Arel node to string
+              s = s.to_sql unless s.is_a?(String)
+              # Remove any ASC/DESC modifiers
+              s.gsub(/\s+(?:ASC|DESC)?\s*(?:NULLS\s+(?:FIRST|LAST)\s*)?/i, '')
+            }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
+
+          [super, *order_columns].join(', ')
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/utils.rb b/activerecord/lib/active_record/connection_adapters/postgresql/utils.rb
new file mode 100644
index 0000000000..0290bcb48c
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/utils.rb
@@ -0,0 +1,66 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      # Value Object to hold a schema qualified name.
+      # This is usually the name of a PostgreSQL relation but it can also represent
+      # schema qualified type names. +schema+ and +identifier+ are unquoted to prevent
+      # double quoting.
+      class Name # :nodoc:
+        SEPARATOR = "."
+        attr_reader :schema, :identifier
+
+        def initialize(schema, identifier)
+          @schema, @identifier = unquote(schema), unquote(identifier)
+        end
+
+        def to_s
+          parts.join SEPARATOR
+        end
+
+        def quoted
+          parts.map { |p| PGconn.quote_ident(p) }.join SEPARATOR
+        end
+
+        def ==(o)
+          o.class == self.class && o.parts == parts
+        end
+        alias_method :eql?, :==
+
+        def hash
+          parts.hash
+        end
+
+        protected
+          def unquote(part)
+            return unless part
+            part.gsub(/(^"|"$)/,'')
+          end
+
+          def parts
+            @parts ||= [@schema, @identifier].compact
+          end
+      end
+
+      module Utils # :nodoc:
+        extend self
+
+        # Returns an instance of <tt>ActiveRecord::ConnectionAdapters::PostgreSQL::Name</tt>
+        # extracted from +string+.
+        # +schema+ is nil if not specified in +string+.
+        # +schema+ and +identifier+ exclude surrounding quotes (regardless of whether provided in +string+)
+        # +string+ supports the range of schema/table references understood by PostgreSQL, for example:
+        #
+        # * <tt>table_name</tt>
+        # * <tt>"table.name"</tt>
+        # * <tt>schema_name.table_name</tt>
+        # * <tt>schema_name."table.name"</tt>
+        # * <tt>"schema_name".table_name</tt>
+        # * <tt>"schema.name"."table name"</tt>
+        def extract_schema_qualified_name(string)
+          table, schema = string.scan(/[^".\s]+|"[^"]*"/)[0..1].reverse
+          PostgreSQL::Name.new(schema, table)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
new file mode 100644
index 0000000000..eede374678
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -0,0 +1,743 @@
+require 'active_record/connection_adapters/abstract_adapter'
+require 'active_record/connection_adapters/statement_pool'
+
+require 'active_record/connection_adapters/postgresql/utils'
+require 'active_record/connection_adapters/postgresql/column'
+require 'active_record/connection_adapters/postgresql/oid'
+require 'active_record/connection_adapters/postgresql/quoting'
+require 'active_record/connection_adapters/postgresql/referential_integrity'
+require 'active_record/connection_adapters/postgresql/schema_definitions'
+require 'active_record/connection_adapters/postgresql/schema_statements'
+require 'active_record/connection_adapters/postgresql/database_statements'
+
+require 'arel/visitors/bind_visitor'
+
+# Make sure we're using pg high enough for PGResult#values
+gem 'pg', '~> 0.11'
+require 'pg'
+
+require 'ipaddr'
+
+module ActiveRecord
+  module ConnectionHandling # :nodoc:
+    VALID_CONN_PARAMS = [:host, :hostaddr, :port, :dbname, :user, :password, :connect_timeout,
+                         :client_encoding, :options, :application_name, :fallback_application_name,
+                         :keepalives, :keepalives_idle, :keepalives_interval, :keepalives_count,
+                         :tty, :sslmode, :requiressl, :sslcompression, :sslcert, :sslkey,
+                         :sslrootcert, :sslcrl, :requirepeer, :krbsrvname, :gsslib, :service]
+
+    # Establishes a connection to the database that's used by all Active Record objects
+    def postgresql_connection(config)
+      conn_params = config.symbolize_keys
+
+      conn_params.delete_if { |_, v| v.nil? }
+
+      # Map ActiveRecords param names to PGs.
+      conn_params[:user] = conn_params.delete(:username) if conn_params[:username]
+      conn_params[:dbname] = conn_params.delete(:database) if conn_params[:database]
+
+      # Forward only valid config params to PGconn.connect.
+      conn_params.keep_if { |k, _| VALID_CONN_PARAMS.include?(k) }
+
+      # The postgres drivers don't allow the creation of an unconnected PGconn object,
+      # so just pass a nil connection object for the time being.
+      ConnectionAdapters::PostgreSQLAdapter.new(nil, logger, conn_params, config)
+    end
+  end
+
+  module ConnectionAdapters
+    # The PostgreSQL adapter works with the native C (https://bitbucket.org/ged/ruby-pg) driver.
+    #
+    # Options:
+    #
+    # * <tt>:host</tt> - Defaults to a Unix-domain socket in /tmp. On machines without Unix-domain sockets,
+    #   the default is to connect to localhost.
+    # * <tt>:port</tt> - Defaults to 5432.
+    # * <tt>:username</tt> - Defaults to be the same as the operating system name of the user running the application.
+    # * <tt>:password</tt> - Password to be used if the server demands password authentication.
+    # * <tt>:database</tt> - Defaults to be the same as the user name.
+    # * <tt>:schema_search_path</tt> - An optional schema search path for the connection given
+    #   as a string of comma-separated schema names. This is backward-compatible with the <tt>:schema_order</tt> option.
+    # * <tt>:encoding</tt> - An optional client encoding that is used in a <tt>SET client_encoding TO
+    #   <encoding></tt> call on the connection.
+    # * <tt>:min_messages</tt> - An optional client min messages that is used in a
+    #   <tt>SET client_min_messages TO <min_messages></tt> call on the connection.
+    # * <tt>:variables</tt> - An optional hash of additional parameters that
+    #   will be used in <tt>SET SESSION key = val</tt> calls on the connection.
+    # * <tt>:insert_returning</tt> - An optional boolean to control the use or <tt>RETURNING</tt> for <tt>INSERT</tt> statements
+    #   defaults to true.
+    #
+    # Any further options are used as connection parameters to libpq. See
+    # http://www.postgresql.org/docs/9.1/static/libpq-connect.html for the
+    # list of parameters.
+    #
+    # In addition, default connection parameters of libpq can be set per environment variables.
+    # See http://www.postgresql.org/docs/9.1/static/libpq-envars.html .
+    class PostgreSQLAdapter < AbstractAdapter
+      ADAPTER_NAME = 'PostgreSQL'
+
+      NATIVE_DATABASE_TYPES = {
+        primary_key: "serial primary key",
+        string:      { name: "character varying" },
+        text:        { name: "text" },
+        integer:     { name: "integer" },
+        float:       { name: "float" },
+        decimal:     { name: "decimal" },
+        datetime:    { name: "timestamp" },
+        time:        { name: "time" },
+        date:        { name: "date" },
+        daterange:   { name: "daterange" },
+        numrange:    { name: "numrange" },
+        tsrange:     { name: "tsrange" },
+        tstzrange:   { name: "tstzrange" },
+        int4range:   { name: "int4range" },
+        int8range:   { name: "int8range" },
+        binary:      { name: "bytea" },
+        boolean:     { name: "boolean" },
+        xml:         { name: "xml" },
+        tsvector:    { name: "tsvector" },
+        hstore:      { name: "hstore" },
+        inet:        { name: "inet" },
+        cidr:        { name: "cidr" },
+        macaddr:     { name: "macaddr" },
+        uuid:        { name: "uuid" },
+        json:        { name: "json" },
+        ltree:       { name: "ltree" },
+        citext:      { name: "citext" },
+        point:       { name: "point" },
+        bit:         { name: "bit" },
+        bit_varying: { name: "bit varying" },
+        money:       { name: "money" },
+      }
+
+      OID = PostgreSQL::OID #:nodoc:
+
+      include PostgreSQL::Quoting
+      include PostgreSQL::ReferentialIntegrity
+      include PostgreSQL::SchemaStatements
+      include PostgreSQL::DatabaseStatements
+      include Savepoints
+
+      # Returns 'PostgreSQL' as adapter name for identification purposes.
+      def adapter_name
+        ADAPTER_NAME
+      end
+
+      def schema_creation # :nodoc:
+        PostgreSQL::SchemaCreation.new self
+      end
+
+      # Adds `:array` option to the default set provided by the
+      # AbstractAdapter
+      def prepare_column_options(column, types) # :nodoc:
+        spec = super
+        spec[:array] = 'true' if column.respond_to?(:array) && column.array
+        spec[:default] = "\"#{column.default_function}\"" if column.default_function
+        spec
+      end
+
+      # Adds `:array` as a valid migration key
+      def migration_keys
+        super + [:array]
+      end
+
+      # Returns +true+, since this connection adapter supports prepared statement
+      # caching.
+      def supports_statement_cache?
+        true
+      end
+
+      def supports_index_sort_order?
+        true
+      end
+
+      def supports_partial_index?
+        true
+      end
+
+      def supports_transaction_isolation?
+        true
+      end
+
+      def supports_foreign_keys?
+        true
+      end
+
+      def index_algorithms
+        { concurrently: 'CONCURRENTLY' }
+      end
+
+      class StatementPool < ConnectionAdapters::StatementPool
+        def initialize(connection, max)
+          super
+          @counter = 0
+          @cache   = Hash.new { |h,pid| h[pid] = {} }
+        end
+
+        def each(&block); cache.each(&block); end
+        def key?(key);    cache.key?(key); end
+        def [](key);      cache[key]; end
+        def length;       cache.length; end
+
+        def next_key
+          "a#{@counter + 1}"
+        end
+
+        def []=(sql, key)
+          while @max <= cache.size
+            dealloc(cache.shift.last)
+          end
+          @counter += 1
+          cache[sql] = key
+        end
+
+        def clear
+          cache.each_value do |stmt_key|
+            dealloc stmt_key
+          end
+          cache.clear
+        end
+
+        def delete(sql_key)
+          dealloc cache[sql_key]
+          cache.delete sql_key
+        end
+
+        private
+
+          def cache
+            @cache[Process.pid]
+          end
+
+          def dealloc(key)
+            @connection.query "DEALLOCATE #{key}" if connection_active?
+          end
+
+          def connection_active?
+            @connection.status == PGconn::CONNECTION_OK
+          rescue PGError
+            false
+          end
+      end
+
+      # Initializes and connects a PostgreSQL adapter.
+      def initialize(connection, logger, connection_parameters, config)
+        super(connection, logger)
+
+        @visitor = Arel::Visitors::PostgreSQL.new self
+        if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
+          @prepared_statements = true
+        else
+          @prepared_statements = false
+        end
+
+        @connection_parameters, @config = connection_parameters, config
+
+        # @local_tz is initialized as nil to avoid warnings when connect tries to use it
+        @local_tz = nil
+        @table_alias_length = nil
+
+        connect
+        @statements = StatementPool.new @connection,
+                                        self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 })
+
+        if postgresql_version < 80200
+          raise "Your version of PostgreSQL (#{postgresql_version}) is too old, please upgrade!"
+        end
+
+        @type_map = Type::HashLookupTypeMap.new
+        initialize_type_map(type_map)
+        @local_tz = execute('SHOW TIME ZONE', 'SCHEMA').first["TimeZone"]
+        @use_insert_returning = @config.key?(:insert_returning) ? self.class.type_cast_config_to_boolean(@config[:insert_returning]) : true
+      end
+
+      # Clears the prepared statements cache.
+      def clear_cache!
+        @statements.clear
+      end
+
+      # Is this connection alive and ready for queries?
+      def active?
+        @connection.query 'SELECT 1'
+        true
+      rescue PGError
+        false
+      end
+
+      # Close then reopen the connection.
+      def reconnect!
+        super
+        @connection.reset
+        configure_connection
+      end
+
+      def reset!
+        clear_cache!
+        reset_transaction
+        unless @connection.transaction_status == ::PG::PQTRANS_IDLE
+          @connection.query 'ROLLBACK'
+        end
+        @connection.query 'DISCARD ALL'
+        configure_connection
+      end
+
+      # Disconnects from the database if already connected. Otherwise, this
+      # method does nothing.
+      def disconnect!
+        super
+        @connection.close rescue nil
+      end
+
+      def native_database_types #:nodoc:
+        NATIVE_DATABASE_TYPES
+      end
+
+      # Returns true, since this connection adapter supports migrations.
+      def supports_migrations?
+        true
+      end
+
+      # Does PostgreSQL support finding primary key on non-Active Record tables?
+      def supports_primary_key? #:nodoc:
+        true
+      end
+
+      # Enable standard-conforming strings if available.
+      def set_standard_conforming_strings
+        old, self.client_min_messages = client_min_messages, 'panic'
+        execute('SET standard_conforming_strings = on', 'SCHEMA') rescue nil
+      ensure
+        self.client_min_messages = old
+      end
+
+      def supports_ddl_transactions?
+        true
+      end
+
+      def supports_explain?
+        true
+      end
+
+      # Returns true if pg > 9.1
+      def supports_extensions?
+        postgresql_version >= 90100
+      end
+
+      # Range datatypes weren't introduced until PostgreSQL 9.2
+      def supports_ranges?
+        postgresql_version >= 90200
+      end
+
+      def supports_materialized_views?
+        postgresql_version >= 90300
+      end
+
+      def enable_extension(name)
+        exec_query("CREATE EXTENSION IF NOT EXISTS \"#{name}\"").tap {
+          reload_type_map
+        }
+      end
+
+      def disable_extension(name)
+        exec_query("DROP EXTENSION IF EXISTS \"#{name}\" CASCADE").tap {
+          reload_type_map
+        }
+      end
+
+      def extension_enabled?(name)
+        if supports_extensions?
+          res = exec_query "SELECT EXISTS(SELECT * FROM pg_available_extensions WHERE name = '#{name}' AND installed_version IS NOT NULL) as enabled",
+            'SCHEMA'
+          res.cast_values.first
+        end
+      end
+
+      def extensions
+        if supports_extensions?
+          exec_query("SELECT extname from pg_extension", "SCHEMA").cast_values
+        else
+          super
+        end
+      end
+
+      # Returns the configured supported identifier length supported by PostgreSQL
+      def table_alias_length
+        @table_alias_length ||= query('SHOW max_identifier_length', 'SCHEMA')[0][0].to_i
+      end
+
+      # Set the authorized user for this session
+      def session_auth=(user)
+        clear_cache!
+        exec_query "SET SESSION AUTHORIZATION #{user}"
+      end
+
+      def use_insert_returning?
+        @use_insert_returning
+      end
+
+      def valid_type?(type)
+        !native_database_types[type].nil?
+      end
+
+      def update_table_definition(table_name, base) #:nodoc:
+        PostgreSQL::Table.new(table_name, base)
+      end
+
+      def lookup_cast_type(sql_type) # :nodoc:
+        oid = execute("SELECT #{quote(sql_type)}::regtype::oid", "SCHEMA").first['oid'].to_i
+        super(oid)
+      end
+
+      protected
+
+        # Returns the version of the connected PostgreSQL server.
+        def postgresql_version
+          @connection.server_version
+        end
+
+        # See http://www.postgresql.org/docs/9.1/static/errcodes-appendix.html
+        FOREIGN_KEY_VIOLATION = "23503"
+        UNIQUE_VIOLATION      = "23505"
+
+        def translate_exception(exception, message)
+          return exception unless exception.respond_to?(:result)
+
+          case exception.result.try(:error_field, PGresult::PG_DIAG_SQLSTATE)
+          when UNIQUE_VIOLATION
+            RecordNotUnique.new(message, exception)
+          when FOREIGN_KEY_VIOLATION
+            InvalidForeignKey.new(message, exception)
+          else
+            super
+          end
+        end
+
+      private
+
+        def get_oid_type(oid, fmod, column_name, sql_type = '') # :nodoc:
+          if !type_map.key?(oid)
+            load_additional_types(type_map, [oid])
+          end
+
+          type_map.fetch(oid, fmod, sql_type) {
+            warn "unknown OID #{oid}: failed to recognize type of '#{column_name}'. It will be treated as String."
+            Type::Value.new.tap do |cast_type|
+              type_map.register_type(oid, cast_type)
+            end
+          }
+        end
+
+        def initialize_type_map(m) # :nodoc:
+          register_class_with_limit m, 'int2', OID::Integer
+          m.alias_type 'int4', 'int2'
+          m.alias_type 'int8', 'int2'
+          m.alias_type 'oid', 'int2'
+          m.register_type 'float4', OID::Float.new
+          m.alias_type 'float8', 'float4'
+          m.register_type 'text', Type::Text.new
+          register_class_with_limit m, 'varchar', Type::String
+          m.alias_type 'char', 'varchar'
+          m.alias_type 'name', 'varchar'
+          m.alias_type 'bpchar', 'varchar'
+          m.register_type 'bool', Type::Boolean.new
+          register_class_with_limit m, 'bit', OID::Bit
+          register_class_with_limit m, 'varbit', OID::BitVarying
+          m.alias_type 'timestamptz', 'timestamp'
+          m.register_type 'date', OID::Date.new
+          m.register_type 'time', OID::Time.new
+
+          m.register_type 'money', OID::Money.new
+          m.register_type 'bytea', OID::Bytea.new
+          m.register_type 'point', OID::Point.new
+          m.register_type 'hstore', OID::Hstore.new
+          m.register_type 'json', OID::Json.new
+          m.register_type 'jsonb', OID::Jsonb.new
+          m.register_type 'cidr', OID::Cidr.new
+          m.register_type 'inet', OID::Inet.new
+          m.register_type 'uuid', OID::Uuid.new
+          m.register_type 'xml', OID::Xml.new
+          m.register_type 'tsvector', OID::SpecializedString.new(:tsvector)
+          m.register_type 'macaddr', OID::SpecializedString.new(:macaddr)
+          m.register_type 'citext', OID::SpecializedString.new(:citext)
+          m.register_type 'ltree', OID::SpecializedString.new(:ltree)
+
+          # FIXME: why are we keeping these types as strings?
+          m.alias_type 'interval', 'varchar'
+          m.alias_type 'path', 'varchar'
+          m.alias_type 'line', 'varchar'
+          m.alias_type 'polygon', 'varchar'
+          m.alias_type 'circle', 'varchar'
+          m.alias_type 'lseg', 'varchar'
+          m.alias_type 'box', 'varchar'
+
+          m.register_type 'timestamp' do |_, _, sql_type|
+            precision = extract_precision(sql_type)
+            OID::DateTime.new(precision: precision)
+          end
+
+          m.register_type 'numeric' do |_, fmod, sql_type|
+            precision = extract_precision(sql_type)
+            scale = extract_scale(sql_type)
+
+            # The type for the numeric depends on the width of the field,
+            # so we'll do something special here.
+            #
+            # When dealing with decimal columns:
+            #
+            # places after decimal  = fmod - 4 & 0xffff
+            # places before decimal = (fmod - 4) >> 16 & 0xffff
+            if fmod && (fmod - 4 & 0xffff).zero?
+              # FIXME: Remove this class, and the second argument to
+              # lookups on PG
+              Type::DecimalWithoutScale.new(precision: precision)
+            else
+              OID::Decimal.new(precision: precision, scale: scale)
+            end
+          end
+
+          load_additional_types(m)
+        end
+
+        def extract_limit(sql_type) # :nodoc:
+          case sql_type
+          when /^bigint/i;    8
+          when /^smallint/i;  2
+          else super
+          end
+        end
+
+        # Extracts the value from a PostgreSQL column default definition.
+        def extract_value_from_default(oid, default) # :nodoc:
+          case default
+            # Quoted types
+            when /\A[\(B]?'(.*)'::/m
+              $1.gsub(/''/, "'")
+            # Boolean types
+            when 'true', 'false'
+              default
+            # Numeric types
+            when /\A\(?(-?\d+(\.\d*)?\)?(::bigint)?)\z/
+              $1
+            # Object identifier types
+            when /\A-?\d+\z/
+              $1
+            else
+              # Anything else is blank, some user type, or some function
+              # and we can't know the value of that, so return nil.
+              nil
+          end
+        end
+
+        def extract_default_function(default_value, default) # :nodoc:
+          default if has_default_function?(default_value, default)
+        end
+
+        def has_default_function?(default_value, default) # :nodoc:
+          !default_value && (%r{\w+\(.*\)} === default)
+        end
+
+        def load_additional_types(type_map, oids = nil) # :nodoc:
+          if supports_ranges?
+            query = <<-SQL
+              SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, r.rngsubtype, t.typtype, t.typbasetype
+              FROM pg_type as t
+              LEFT JOIN pg_range as r ON oid = rngtypid
+            SQL
+          else
+            query = <<-SQL
+              SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, t.typtype, t.typbasetype
+              FROM pg_type as t
+            SQL
+          end
+
+          if oids
+            query += "WHERE t.oid::integer IN (%s)" % oids.join(", ")
+          end
+
+          initializer = OID::TypeMapInitializer.new(type_map)
+          records = execute(query, 'SCHEMA')
+          initializer.run(records)
+        end
+
+        FEATURE_NOT_SUPPORTED = "0A000" #:nodoc:
+
+        def execute_and_clear(sql, name, binds)
+          result = without_prepared_statement?(binds) ? exec_no_cache(sql, name, binds) :
+                                                        exec_cache(sql, name, binds)
+          ret = yield result
+          result.clear
+          ret
+        end
+
+        def exec_no_cache(sql, name, binds)
+          log(sql, name, binds) { @connection.async_exec(sql, []) }
+        end
+
+        def exec_cache(sql, name, binds)
+          stmt_key = prepare_statement(sql)
+          type_casted_binds = binds.map { |col, val|
+            [col, type_cast(val, col)]
+          }
+
+          log(sql, name, type_casted_binds, stmt_key) do
+            @connection.send_query_prepared(stmt_key, type_casted_binds.map { |_, val| val })
+            @connection.block
+            @connection.get_last_result
+          end
+        rescue ActiveRecord::StatementInvalid => e
+          pgerror = e.original_exception
+
+          # Get the PG code for the failure.  Annoyingly, the code for
+          # prepared statements whose return value may have changed is
+          # FEATURE_NOT_SUPPORTED.  Check here for more details:
+          # http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573
+          begin
+            code = pgerror.result.result_error_field(PGresult::PG_DIAG_SQLSTATE)
+          rescue
+            raise e
+          end
+          if FEATURE_NOT_SUPPORTED == code
+            @statements.delete sql_key(sql)
+            retry
+          else
+            raise e
+          end
+        end
+
+        # Returns the statement identifier for the client side cache
+        # of statements
+        def sql_key(sql)
+          "#{schema_search_path}-#{sql}"
+        end
+
+        # Prepare the statement if it hasn't been prepared, return
+        # the statement key.
+        def prepare_statement(sql)
+          sql_key = sql_key(sql)
+          unless @statements.key? sql_key
+            nextkey = @statements.next_key
+            begin
+              @connection.prepare nextkey, sql
+            rescue => e
+              raise translate_exception_class(e, sql)
+            end
+            # Clear the queue
+            @connection.get_last_result
+            @statements[sql_key] = nextkey
+          end
+          @statements[sql_key]
+        end
+
+        # Connects to a PostgreSQL server and sets up the adapter depending on the
+        # connected server's characteristics.
+        def connect
+          @connection = PGconn.connect(@connection_parameters)
+
+          # Money type has a fixed precision of 10 in PostgreSQL 8.2 and below, and as of
+          # PostgreSQL 8.3 it has a fixed precision of 19. PostgreSQLColumn.extract_precision
+          # should know about this but can't detect it there, so deal with it here.
+          OID::Money.precision = (postgresql_version >= 80300) ? 19 : 10
+
+          configure_connection
+        rescue ::PG::Error => error
+          if error.message.include?("does not exist")
+            raise ActiveRecord::NoDatabaseError.new(error.message, error)
+          else
+            raise
+          end
+        end
+
+        # Configures the encoding, verbosity, schema search path, and time zone of the connection.
+        # This is called by #connect and should not be called manually.
+        def configure_connection
+          if @config[:encoding]
+            @connection.set_client_encoding(@config[:encoding])
+          end
+          self.client_min_messages = @config[:min_messages] || 'warning'
+          self.schema_search_path = @config[:schema_search_path] || @config[:schema_order]
+
+          # Use standard-conforming strings if available so we don't have to do the E'...' dance.
+          set_standard_conforming_strings
+
+          # If using Active Record's time zone support configure the connection to return
+          # TIMESTAMP WITH ZONE types in UTC.
+          # (SET TIME ZONE does not use an equals sign like other SET variables)
+          if ActiveRecord::Base.default_timezone == :utc
+            execute("SET time zone 'UTC'", 'SCHEMA')
+          elsif @local_tz
+            execute("SET time zone '#{@local_tz}'", 'SCHEMA')
+          end
+
+          # SET statements from :variables config hash
+          # http://www.postgresql.org/docs/8.3/static/sql-set.html
+          variables = @config[:variables] || {}
+          variables.map do |k, v|
+            if v == ':default' || v == :default
+              # Sets the value to the global or compile default
+              execute("SET SESSION #{k.to_s} TO DEFAULT", 'SCHEMA')
+            elsif !v.nil?
+              execute("SET SESSION #{k.to_s} TO #{quote(v)}", 'SCHEMA')
+            end
+          end
+        end
+
+        # Returns the current ID of a table's sequence.
+        def last_insert_id(sequence_name) #:nodoc:
+          Integer(last_insert_id_value(sequence_name))
+        end
+
+        def last_insert_id_value(sequence_name)
+          last_insert_id_result(sequence_name).rows.first.first
+        end
+
+        def last_insert_id_result(sequence_name) #:nodoc:
+          exec_query("SELECT currval('#{sequence_name}')", 'SQL')
+        end
+
+        # Executes a SELECT query and returns the results, performing any data type
+        # conversions that are required to be performed here instead of in PostgreSQLColumn.
+        def select(sql, name = nil, binds = [])
+          exec_query(sql, name, binds)
+        end
+
+        # Returns the list of a table's column names, data types, and default values.
+        #
+        # The underlying query is roughly:
+        #  SELECT column.name, column.type, default.value
+        #    FROM column LEFT JOIN default
+        #      ON column.table_id = default.table_id
+        #     AND column.num = default.column_num
+        #   WHERE column.table_id = get_table_id('table_name')
+        #     AND column.num > 0
+        #     AND NOT column.is_dropped
+        #   ORDER BY column.num
+        #
+        # If the table name is not prefixed with a schema, the database will
+        # take the first match from the schema search path.
+        #
+        # Query implementation notes:
+        #  - format_type includes the column size constraint, e.g. varchar(50)
+        #  - ::regclass is a function that gives the id for a table name
+        def column_definitions(table_name) # :nodoc:
+          exec_query(<<-end_sql, 'SCHEMA').rows
+              SELECT a.attname, format_type(a.atttypid, a.atttypmod),
+                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
+                FROM pg_attribute a LEFT JOIN pg_attrdef d
+                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
+               WHERE a.attrelid = '#{quote_table_name(table_name)}'::regclass
+                 AND a.attnum > 0 AND NOT a.attisdropped
+               ORDER BY a.attnum
+          end_sql
+        end
+
+        def extract_table_ref_from_insert_sql(sql) # :nodoc:
+          sql[/into\s+([^\(]*).*values\s*\(/im]
+          $1.strip if $1
+        end
+
+        def create_table_definition(name, temporary, options, as = nil) # :nodoc:
+          PostgreSQL::TableDefinition.new native_database_types, name, temporary, options, as
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/schema_cache.rb b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
new file mode 100644
index 0000000000..a10ce330c7
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
@@ -0,0 +1,94 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class SchemaCache
+      attr_reader :version
+      attr_accessor :connection
+
+      def initialize(conn)
+        @connection = conn
+
+        @columns      = {}
+        @columns_hash = {}
+        @primary_keys = {}
+        @tables       = {}
+      end
+
+      def primary_keys(table_name)
+        @primary_keys[table_name] ||= table_exists?(table_name) ? connection.primary_key(table_name) : nil
+      end
+
+      # A cached lookup for table existence.
+      def table_exists?(name)
+        prepare_tables if @tables.empty?
+        return @tables[name] if @tables.key? name
+
+        @tables[name] = connection.table_exists?(name)
+      end
+
+      # Add internal cache for table with +table_name+.
+      def add(table_name)
+        if table_exists?(table_name)
+          primary_keys(table_name)
+          columns(table_name)
+          columns_hash(table_name)
+        end
+      end
+
+      def tables(name)
+        @tables[name]
+      end
+
+      # Get the columns for a table
+      def columns(table_name)
+        @columns[table_name] ||= connection.columns(table_name)
+      end
+
+      # Get the columns for a table as a hash, key is the column name
+      # value is the column object.
+      def columns_hash(table_name)
+        @columns_hash[table_name] ||= Hash[columns(table_name).map { |col|
+          [col.name, col]
+        }]
+      end
+
+      # Clears out internal caches
+      def clear!
+        @columns.clear
+        @columns_hash.clear
+        @primary_keys.clear
+        @tables.clear
+        @version = nil
+      end
+
+      def size
+        [@columns, @columns_hash, @primary_keys, @tables].map { |x|
+          x.size
+        }.inject :+
+      end
+
+      # Clear out internal caches for table with +table_name+.
+      def clear_table_cache!(table_name)
+        @columns.delete table_name
+        @columns_hash.delete table_name
+        @primary_keys.delete table_name
+        @tables.delete table_name
+      end
+
+      def marshal_dump
+        # if we get current version during initialization, it happens stack over flow.
+        @version = ActiveRecord::Migrator.current_version
+        [@version, @columns, @columns_hash, @primary_keys, @tables]
+      end
+
+      def marshal_load(array)
+        @version, @columns, @columns_hash, @primary_keys, @tables = array
+      end
+
+      private
+
+        def prepare_tables
+          connection.tables.each { |table| @tables[table] = true }
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
new file mode 100644
index 0000000000..faf1cdc686
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -0,0 +1,633 @@
+require 'active_record/connection_adapters/abstract_adapter'
+require 'active_record/connection_adapters/statement_pool'
+require 'arel/visitors/bind_visitor'
+
+gem 'sqlite3', '~> 1.3.6'
+require 'sqlite3'
+
+module ActiveRecord
+  module ConnectionHandling # :nodoc:
+    # sqlite3 adapter reuses sqlite_connection.
+    def sqlite3_connection(config)
+      # Require database.
+      unless config[:database]
+        raise ArgumentError, "No database file specified. Missing argument: database"
+      end
+
+      # Allow database path relative to Rails.root, but only if the database
+      # path is not the special path that tells sqlite to build a database only
+      # in memory.
+      if ':memory:' != config[:database]
+        config[:database] = File.expand_path(config[:database], Rails.root) if defined?(Rails.root)
+        dirname = File.dirname(config[:database])
+        Dir.mkdir(dirname) unless File.directory?(dirname)
+      end
+
+      db = SQLite3::Database.new(
+        config[:database].to_s,
+        :results_as_hash => true
+      )
+
+      db.busy_timeout(ConnectionAdapters::SQLite3Adapter.type_cast_config_to_integer(config[:timeout])) if config[:timeout]
+
+      ConnectionAdapters::SQLite3Adapter.new(db, logger, nil, config)
+    rescue Errno::ENOENT => error
+      if error.message.include?("No such file or directory")
+        raise ActiveRecord::NoDatabaseError.new(error.message, error)
+      else
+        raise
+      end
+    end
+  end
+
+  module ConnectionAdapters #:nodoc:
+    class SQLite3Binary < Type::Binary # :nodoc:
+      def cast_value(value)
+        if value.encoding != Encoding::ASCII_8BIT
+          value = value.force_encoding(Encoding::ASCII_8BIT)
+        end
+        value
+      end
+    end
+
+    class SQLite3String < Type::String # :nodoc:
+      def type_cast_for_database(value)
+        if value.is_a?(::String) && value.encoding == Encoding::ASCII_8BIT
+          value.encode(Encoding::UTF_8)
+        else
+          super
+        end
+      end
+    end
+
+    # The SQLite3 adapter works SQLite 3.6.16 or newer
+    # with the sqlite3-ruby drivers (available as gem from https://rubygems.org/gems/sqlite3).
+    #
+    # Options:
+    #
+    # * <tt>:database</tt> - Path to the database file.
+    class SQLite3Adapter < AbstractAdapter
+      include Savepoints
+
+      NATIVE_DATABASE_TYPES = {
+        primary_key:  'INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL',
+        string:       { name: "varchar" },
+        text:         { name: "text" },
+        integer:      { name: "integer" },
+        float:        { name: "float" },
+        decimal:      { name: "decimal" },
+        datetime:     { name: "datetime" },
+        time:         { name: "time" },
+        date:         { name: "date" },
+        binary:       { name: "blob" },
+        boolean:      { name: "boolean" }
+      }
+
+      class Version
+        include Comparable
+
+        def initialize(version_string)
+          @version = version_string.split('.').map { |v| v.to_i }
+        end
+
+        def <=>(version_string)
+          @version <=> version_string.split('.').map { |v| v.to_i }
+        end
+      end
+
+      class StatementPool < ConnectionAdapters::StatementPool
+        def initialize(connection, max)
+          super
+          @cache = Hash.new { |h,pid| h[pid] = {} }
+        end
+
+        def each(&block); cache.each(&block); end
+        def key?(key);    cache.key?(key); end
+        def [](key);      cache[key]; end
+        def length;       cache.length; end
+
+        def []=(sql, key)
+          while @max <= cache.size
+            dealloc(cache.shift.last[:stmt])
+          end
+          cache[sql] = key
+        end
+
+        def clear
+          cache.values.each do |hash|
+            dealloc hash[:stmt]
+          end
+          cache.clear
+        end
+
+        private
+        def cache
+          @cache[$$]
+        end
+
+        def dealloc(stmt)
+          stmt.close unless stmt.closed?
+        end
+      end
+
+      def initialize(connection, logger, connection_options, config)
+        super(connection, logger)
+
+        @active     = nil
+        @statements = StatementPool.new(@connection,
+                                        self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 }))
+        @config = config
+
+        @visitor = Arel::Visitors::SQLite.new self
+
+        if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
+          @prepared_statements = true
+        else
+          @prepared_statements = false
+        end
+      end
+
+      def adapter_name #:nodoc:
+        'SQLite'
+      end
+
+      def supports_ddl_transactions?
+        true
+      end
+
+      def supports_savepoints?
+        true
+      end
+
+      def supports_partial_index?
+        sqlite_version >= '3.8.0'
+      end
+
+      # Returns true, since this connection adapter supports prepared statement
+      # caching.
+      def supports_statement_cache?
+        true
+      end
+
+      # Returns true, since this connection adapter supports migrations.
+      def supports_migrations? #:nodoc:
+        true
+      end
+
+      def supports_primary_key? #:nodoc:
+        true
+      end
+
+      def requires_reloading?
+        true
+      end
+
+      def supports_add_column?
+        true
+      end
+
+      def active?
+        @active != false
+      end
+
+      # Disconnects from the database if already connected. Otherwise, this
+      # method does nothing.
+      def disconnect!
+        super
+        @active = false
+        @connection.close rescue nil
+      end
+
+      # Clears the prepared statements cache.
+      def clear_cache!
+        @statements.clear
+      end
+
+      def supports_index_sort_order?
+        true
+      end
+
+      # Returns 62. SQLite supports index names up to 64
+      # characters. The rest is used by rails internally to perform
+      # temporary rename operations
+      def allowed_index_name_length
+        index_name_length - 2
+      end
+
+      def native_database_types #:nodoc:
+        NATIVE_DATABASE_TYPES
+      end
+
+      # Returns the current database encoding format as a string, eg: 'UTF-8'
+      def encoding
+        @connection.encoding.to_s
+      end
+
+      def supports_explain?
+        true
+      end
+
+      # QUOTING ==================================================
+
+      def _quote(value) # :nodoc:
+        case value
+        when Type::Binary::Data
+          "x'#{value.hex}'"
+        else
+          super
+        end
+      end
+
+      def _type_cast(value) # :nodoc:
+        case value
+        when BigDecimal
+          value.to_f
+        else
+          super
+        end
+      end
+
+      def quote_string(s) #:nodoc:
+        @connection.class.quote(s)
+      end
+
+      def quote_table_name_for_assignment(table, attr)
+        quote_column_name(attr)
+      end
+
+      def quote_column_name(name) #:nodoc:
+        %Q("#{name.to_s.gsub('"', '""')}")
+      end
+
+      # Quote date/time values for use in SQL input. Includes microseconds
+      # if the value is a Time responding to usec.
+      def quoted_date(value) #:nodoc:
+        if value.respond_to?(:usec)
+          "#{super}.#{sprintf("%06d", value.usec)}"
+        else
+          super
+        end
+      end
+
+      # DATABASE STATEMENTS ======================================
+
+      def explain(arel, binds = [])
+        sql = "EXPLAIN QUERY PLAN #{to_sql(arel, binds)}"
+        ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', []))
+      end
+
+      class ExplainPrettyPrinter
+        # Pretty prints the result of a EXPLAIN QUERY PLAN in a way that resembles
+        # the output of the SQLite shell:
+        #
+        #   0|0|0|SEARCH TABLE users USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)
+        #   0|1|1|SCAN TABLE posts (~100000 rows)
+        #
+        def pp(result) # :nodoc:
+          result.rows.map do |row|
+            row.join('|')
+          end.join("\n") + "\n"
+        end
+      end
+
+      def exec_query(sql, name = nil, binds = [])
+        type_casted_binds = binds.map { |col, val|
+          [col, type_cast(val, col)]
+        }
+
+        log(sql, name, type_casted_binds) do
+          # Don't cache statements if they are not prepared
+          if without_prepared_statement?(binds)
+            stmt    = @connection.prepare(sql)
+            begin
+              cols    = stmt.columns
+              records = stmt.to_a
+            ensure
+              stmt.close
+            end
+            stmt = records
+          else
+            cache = @statements[sql] ||= {
+              :stmt => @connection.prepare(sql)
+            }
+            stmt = cache[:stmt]
+            cols = cache[:cols] ||= stmt.columns
+            stmt.reset!
+            stmt.bind_params type_casted_binds.map { |_, val| val }
+          end
+
+          ActiveRecord::Result.new(cols, stmt.to_a)
+        end
+      end
+
+      def exec_delete(sql, name = 'SQL', binds = [])
+        exec_query(sql, name, binds)
+        @connection.changes
+      end
+      alias :exec_update :exec_delete
+
+      def last_inserted_id(result)
+        @connection.last_insert_row_id
+      end
+
+      def execute(sql, name = nil) #:nodoc:
+        log(sql, name) { @connection.execute(sql) }
+      end
+
+      def update_sql(sql, name = nil) #:nodoc:
+        super
+        @connection.changes
+      end
+
+      def delete_sql(sql, name = nil) #:nodoc:
+        sql += " WHERE 1=1" unless sql =~ /WHERE/i
+        super sql, name
+      end
+
+      def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) #:nodoc:
+        super
+        id_value || @connection.last_insert_row_id
+      end
+      alias :create :insert_sql
+
+      def select_rows(sql, name = nil, binds = [])
+        exec_query(sql, name, binds).rows
+      end
+
+      def begin_db_transaction #:nodoc:
+        log('begin transaction',nil) { @connection.transaction }
+      end
+
+      def commit_db_transaction #:nodoc:
+        log('commit transaction',nil) { @connection.commit }
+      end
+
+      def rollback_db_transaction #:nodoc:
+        log('rollback transaction',nil) { @connection.rollback }
+      end
+
+      # SCHEMA STATEMENTS ========================================
+
+      def tables(name = nil, table_name = nil) #:nodoc:
+        sql = <<-SQL
+          SELECT name
+          FROM sqlite_master
+          WHERE type = 'table' AND NOT name = 'sqlite_sequence'
+        SQL
+        sql << " AND name = #{quote_table_name(table_name)}" if table_name
+
+        exec_query(sql, 'SCHEMA').map do |row|
+          row['name']
+        end
+      end
+
+      def table_exists?(table_name)
+        table_name && tables(nil, table_name).any?
+      end
+
+      # Returns an array of +Column+ objects for the table specified by +table_name+.
+      def columns(table_name) #:nodoc:
+        table_structure(table_name).map do |field|
+          case field["dflt_value"]
+          when /^null$/i
+            field["dflt_value"] = nil
+          when /^'(.*)'$/m
+            field["dflt_value"] = $1.gsub("''", "'")
+          when /^"(.*)"$/m
+            field["dflt_value"] = $1.gsub('""', '"')
+          end
+
+          sql_type = field['type']
+          cast_type = lookup_cast_type(sql_type)
+          new_column(field['name'], field['dflt_value'], cast_type, sql_type, field['notnull'].to_i == 0)
+        end
+      end
+
+      # Returns an array of indexes for the given table.
+      def indexes(table_name, name = nil) #:nodoc:
+        exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", 'SCHEMA').map do |row|
+          sql = <<-SQL
+            SELECT sql
+            FROM sqlite_master
+            WHERE name=#{quote(row['name'])} AND type='index'
+            UNION ALL
+            SELECT sql
+            FROM sqlite_temp_master
+            WHERE name=#{quote(row['name'])} AND type='index'
+          SQL
+          index_sql = exec_query(sql).first['sql']
+          match = /\sWHERE\s+(.+)$/i.match(index_sql)
+          where = match[1] if match
+          IndexDefinition.new(
+            table_name,
+            row['name'],
+            row['unique'] != 0,
+            exec_query("PRAGMA index_info('#{row['name']}')", "SCHEMA").map { |col|
+              col['name']
+            }, nil, nil, where)
+        end
+      end
+
+      def primary_key(table_name) #:nodoc:
+        column = table_structure(table_name).find { |field|
+          field['pk'] == 1
+        }
+        column && column['name']
+      end
+
+      def remove_index!(table_name, index_name) #:nodoc:
+        exec_query "DROP INDEX #{quote_column_name(index_name)}"
+      end
+
+      # Renames a table.
+      #
+      # Example:
+      #   rename_table('octopuses', 'octopi')
+      def rename_table(table_name, new_name)
+        exec_query "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
+        rename_table_indexes(table_name, new_name)
+      end
+
+      # See: http://www.sqlite.org/lang_altertable.html
+      # SQLite has an additional restriction on the ALTER TABLE statement
+      def valid_alter_table_options( type, options)
+        type.to_sym != :primary_key
+      end
+
+      def add_column(table_name, column_name, type, options = {}) #:nodoc:
+        if supports_add_column? && valid_alter_table_options( type, options )
+          super(table_name, column_name, type, options)
+        else
+          alter_table(table_name) do |definition|
+            definition.column(column_name, type, options)
+          end
+        end
+      end
+
+      def remove_column(table_name, column_name, type = nil, options = {}) #:nodoc:
+        alter_table(table_name) do |definition|
+          definition.remove_column column_name
+        end
+      end
+
+      def change_column_default(table_name, column_name, default) #:nodoc:
+        alter_table(table_name) do |definition|
+          definition[column_name].default = default
+        end
+      end
+
+      def change_column_null(table_name, column_name, null, default = nil)
+        unless null || default.nil?
+          exec_query("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
+        end
+        alter_table(table_name) do |definition|
+          definition[column_name].null = null
+        end
+      end
+
+      def change_column(table_name, column_name, type, options = {}) #:nodoc:
+        alter_table(table_name) do |definition|
+          include_default = options_include_default?(options)
+          definition[column_name].instance_eval do
+            self.type    = type
+            self.limit   = options[:limit] if options.include?(:limit)
+            self.default = options[:default] if include_default
+            self.null    = options[:null] if options.include?(:null)
+            self.precision = options[:precision] if options.include?(:precision)
+            self.scale   = options[:scale] if options.include?(:scale)
+          end
+        end
+      end
+
+      def rename_column(table_name, column_name, new_column_name) #:nodoc:
+        column = column_for(table_name, column_name)
+        alter_table(table_name, rename: {column.name => new_column_name.to_s})
+        rename_column_indexes(table_name, column.name, new_column_name)
+      end
+
+      protected
+
+        def initialize_type_map(m)
+          super
+          m.register_type(/binary/i, SQLite3Binary.new)
+          register_class_with_limit m, %r(char)i, SQLite3String
+        end
+
+        def select(sql, name = nil, binds = []) #:nodoc:
+          exec_query(sql, name, binds)
+        end
+
+        def table_structure(table_name)
+          structure = exec_query("PRAGMA table_info(#{quote_table_name(table_name)})", 'SCHEMA').to_hash
+          raise(ActiveRecord::StatementInvalid, "Could not find table '#{table_name}'") if structure.empty?
+          structure
+        end
+
+        def alter_table(table_name, options = {}) #:nodoc:
+          altered_table_name = "a#{table_name}"
+          caller = lambda {|definition| yield definition if block_given?}
+
+          transaction do
+            move_table(table_name, altered_table_name,
+              options.merge(:temporary => true))
+            move_table(altered_table_name, table_name, &caller)
+          end
+        end
+
+        def move_table(from, to, options = {}, &block) #:nodoc:
+          copy_table(from, to, options, &block)
+          drop_table(from)
+        end
+
+        def copy_table(from, to, options = {}) #:nodoc:
+          from_primary_key = primary_key(from)
+          options[:id] = false
+          create_table(to, options) do |definition|
+            @definition = definition
+            @definition.primary_key(from_primary_key) if from_primary_key.present?
+            columns(from).each do |column|
+              column_name = options[:rename] ?
+                (options[:rename][column.name] ||
+                 options[:rename][column.name.to_sym] ||
+                 column.name) : column.name
+              next if column_name == from_primary_key
+
+              @definition.column(column_name, column.type,
+                :limit => column.limit, :default => column.default,
+                :precision => column.precision, :scale => column.scale,
+                :null => column.null)
+            end
+            yield @definition if block_given?
+          end
+          copy_table_indexes(from, to, options[:rename] || {})
+          copy_table_contents(from, to,
+            @definition.columns.map {|column| column.name},
+            options[:rename] || {})
+        end
+
+        def copy_table_indexes(from, to, rename = {}) #:nodoc:
+          indexes(from).each do |index|
+            name = index.name
+            if to == "a#{from}"
+              name = "t#{name}"
+            elsif from == "a#{to}"
+              name = name[1..-1]
+            end
+
+            to_column_names = columns(to).map { |c| c.name }
+            columns = index.columns.map {|c| rename[c] || c }.select do |column|
+              to_column_names.include?(column)
+            end
+
+            unless columns.empty?
+              # index name can't be the same
+              opts = { name: name.gsub(/(^|_)(#{from})_/, "\\1#{to}_"), internal: true }
+              opts[:unique] = true if index.unique
+              add_index(to, columns, opts)
+            end
+          end
+        end
+
+        def copy_table_contents(from, to, columns, rename = {}) #:nodoc:
+          column_mappings = Hash[columns.map {|name| [name, name]}]
+          rename.each { |a| column_mappings[a.last] = a.first }
+          from_columns = columns(from).collect {|col| col.name}
+          columns = columns.find_all{|col| from_columns.include?(column_mappings[col])}
+          quoted_columns = columns.map { |col| quote_column_name(col) } * ','
+
+          quoted_to = quote_table_name(to)
+
+          raw_column_mappings = Hash[columns(from).map { |c| [c.name, c] }]
+
+          exec_query("SELECT * FROM #{quote_table_name(from)}").each do |row|
+            sql = "INSERT INTO #{quoted_to} (#{quoted_columns}) VALUES ("
+
+            column_values = columns.map do |col|
+              quote(row[column_mappings[col]], raw_column_mappings[col])
+            end
+
+            sql << column_values * ', '
+            sql << ')'
+            exec_query sql
+          end
+        end
+
+        def sqlite_version
+          @sqlite_version ||= SQLite3Adapter::Version.new(select_value('select sqlite_version(*)'))
+        end
+
+        def translate_exception(exception, message)
+          case exception.message
+          # SQLite 3.8.2 returns a newly formatted error message:
+          #   UNIQUE constraint failed: *table_name*.*column_name*
+          # Older versions of SQLite return:
+          #   column *column_name* is not unique
+          when /column(s)? .* (is|are) not unique/, /UNIQUE constraint failed: .*/
+            RecordNotUnique.new(message, exception)
+          else
+            super
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/statement_pool.rb b/activerecord/lib/active_record/connection_adapters/statement_pool.rb
new file mode 100644
index 0000000000..c6b1bc8b5b
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/statement_pool.rb
@@ -0,0 +1,40 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class StatementPool
+      include Enumerable
+
+      def initialize(connection, max = 1000)
+        @connection = connection
+        @max        = max
+      end
+
+      def each
+        raise NotImplementedError
+      end
+
+      def key?(key)
+        raise NotImplementedError
+      end
+
+      def [](key)
+        raise NotImplementedError
+      end
+
+      def length
+        raise NotImplementedError
+      end
+
+      def []=(sql, key)
+        raise NotImplementedError
+      end
+
+      def clear
+        raise NotImplementedError
+      end
+
+      def delete(key)
+        raise NotImplementedError
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb
new file mode 100644
index 0000000000..31e7390bf7
--- /dev/null
+++ b/activerecord/lib/active_record/connection_handling.rb
@@ -0,0 +1,132 @@
+module ActiveRecord
+  module ConnectionHandling
+    RAILS_ENV   = -> { Rails.env if defined?(Rails) }
+    DEFAULT_ENV = -> { RAILS_ENV.call || "default_env" }
+
+    # Establishes the connection to the database. Accepts a hash as input where
+    # the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)
+    # example for regular databases (MySQL, Postgresql, etc):
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     adapter:  "mysql",
+    #     host:     "localhost",
+    #     username: "myuser",
+    #     password: "mypass",
+    #     database: "somedatabase"
+    #   )
+    #
+    # Example for SQLite database:
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     adapter:  "sqlite3",
+    #     database: "path/to/dbfile"
+    #   )
+    #
+    # Also accepts keys as strings (for parsing from YAML for example):
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     "adapter"  => "sqlite3",
+    #     "database" => "path/to/dbfile"
+    #   )
+    #
+    # Or a URL:
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     "postgres://myuser:mypass@localhost/somedatabase"
+    #   )
+    #
+    # In case <tt>ActiveRecord::Base.configurations</tt> is set (Rails
+    # automatically loads the contents of config/database.yml into it),
+    # a symbol can also be given as argument, representing a key in the
+    # configuration hash:
+    #
+    #   ActiveRecord::Base.establish_connection(:production)
+    #
+    # The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError
+    # may be returned on an error.
+    def establish_connection(spec = nil)
+      spec     ||= DEFAULT_ENV.call.to_sym
+      resolver =   ConnectionAdapters::ConnectionSpecification::Resolver.new configurations
+      spec     =   resolver.spec(spec)
+
+      unless respond_to?(spec.adapter_method)
+        raise AdapterNotFound, "database configuration specifies nonexistent #{spec.config[:adapter]} adapter"
+      end
+
+      remove_connection
+      connection_handler.establish_connection self, spec
+    end
+
+    class MergeAndResolveDefaultUrlConfig # :nodoc:
+      def initialize(raw_configurations)
+        @raw_config = raw_configurations.dup
+        @env = DEFAULT_ENV.call.to_s
+      end
+
+      # Returns fully resolved connection hashes.
+      # Merges connection information from `ENV['DATABASE_URL']` if available.
+      def resolve
+        ConnectionAdapters::ConnectionSpecification::Resolver.new(config).resolve_all
+      end
+
+      private
+        def config
+          @raw_config.dup.tap do |cfg|
+            if url = ENV['DATABASE_URL']
+              cfg[@env] ||= {}
+              cfg[@env]["url"] ||= url
+            end
+          end
+        end
+    end
+
+    # Returns the connection currently associated with the class. This can
+    # also be used to "borrow" the connection to do database work unrelated
+    # to any of the specific Active Records.
+    def connection
+      retrieve_connection
+    end
+
+    def connection_id
+      ActiveRecord::RuntimeRegistry.connection_id
+    end
+
+    def connection_id=(connection_id)
+      ActiveRecord::RuntimeRegistry.connection_id = connection_id
+    end
+
+    # Returns the configuration of the associated connection as a hash:
+    #
+    #  ActiveRecord::Base.connection_config
+    #  # => {pool: 5, timeout: 5000, database: "db/development.sqlite3", adapter: "sqlite3"}
+    #
+    # Please use only for reading.
+    def connection_config
+      connection_pool.spec.config
+    end
+
+    def connection_pool
+      connection_handler.retrieve_connection_pool(self) or raise ConnectionNotEstablished
+    end
+
+    def retrieve_connection
+      connection_handler.retrieve_connection(self)
+    end
+
+    # Returns +true+ if Active Record is connected.
+    def connected?
+      connection_handler.connected?(self)
+    end
+
+    def remove_connection(klass = self)
+      connection_handler.remove_connection(klass)
+    end
+
+    def clear_cache! # :nodoc:
+      connection.schema_cache.clear!
+    end
+
+    delegate :clear_active_connections!, :clear_reloadable_connections!,
+      :clear_all_connections!, :to => :connection_handler
+  end
+end
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
new file mode 100644
index 0000000000..d22806fbdf
--- /dev/null
+++ b/activerecord/lib/active_record/core.rb
@@ -0,0 +1,552 @@
+require 'active_support/core_ext/hash/indifferent_access'
+require 'active_support/core_ext/object/duplicable'
+require 'thread'
+
+module ActiveRecord
+  module Core
+    extend ActiveSupport::Concern
+
+    included do
+      ##
+      # :singleton-method:
+      #
+      # Accepts a logger conforming to the interface of Log4r which is then
+      # passed on to any new database connections made and which can be
+      # retrieved on both a class and instance level by calling +logger+.
+      mattr_accessor :logger, instance_writer: false
+
+      ##
+      # Contains the database configuration - as is typically stored in config/database.yml -
+      # as a Hash.
+      #
+      # For example, the following database.yml...
+      #
+      #   development:
+      #     adapter: sqlite3
+      #     database: db/development.sqlite3
+      #
+      #   production:
+      #     adapter: sqlite3
+      #     database: db/production.sqlite3
+      #
+      # ...would result in ActiveRecord::Base.configurations to look like this:
+      #
+      #   {
+      #      'development' => {
+      #         'adapter'  => 'sqlite3',
+      #         'database' => 'db/development.sqlite3'
+      #      },
+      #      'production' => {
+      #         'adapter'  => 'sqlite3',
+      #         'database' => 'db/production.sqlite3'
+      #      }
+      #   }
+      def self.configurations=(config)
+        @@configurations = ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig.new(config).resolve
+      end
+      self.configurations = {}
+
+      # Returns fully resolved configurations hash
+      def self.configurations
+        @@configurations
+      end
+
+      ##
+      # :singleton-method:
+      # Determines whether to use Time.utc (using :utc) or Time.local (using :local) when pulling
+      # dates and times from the database. This is set to :utc by default.
+      mattr_accessor :default_timezone, instance_writer: false
+      self.default_timezone = :utc
+
+      ##
+      # :singleton-method:
+      # Specifies the format to use when dumping the database schema with Rails'
+      # Rakefile. If :sql, the schema is dumped as (potentially database-
+      # specific) SQL statements. If :ruby, the schema is dumped as an
+      # ActiveRecord::Schema file which can be loaded into any database that
+      # supports migrations. Use :ruby if you want to have different database
+      # adapters for, e.g., your development and test environments.
+      mattr_accessor :schema_format, instance_writer: false
+      self.schema_format = :ruby
+
+      ##
+      # :singleton-method:
+      # Specify whether or not to use timestamps for migration versions
+      mattr_accessor :timestamped_migrations, instance_writer: false
+      self.timestamped_migrations = true
+
+      ##
+      # :singleton-method:
+      # Specify whether schema dump should happen at the end of the
+      # db:migrate rake task. This is true by default, which is useful for the
+      # development environment. This should ideally be false in the production
+      # environment where dumping schema is rarely needed.
+      mattr_accessor :dump_schema_after_migration, instance_writer: false
+      self.dump_schema_after_migration = true
+
+      # :nodoc:
+      mattr_accessor :maintain_test_schema, instance_accessor: false
+
+      def self.disable_implicit_join_references=(value)
+        ActiveSupport::Deprecation.warn("Implicit join references were removed with Rails 4.1." \
+                                        "Make sure to remove this configuration because it does nothing.")
+      end
+
+      class_attribute :default_connection_handler, instance_writer: false
+      class_attribute :find_by_statement_cache
+
+      def self.connection_handler
+        ActiveRecord::RuntimeRegistry.connection_handler || default_connection_handler
+      end
+
+      def self.connection_handler=(handler)
+        ActiveRecord::RuntimeRegistry.connection_handler = handler
+      end
+
+      self.default_connection_handler = ConnectionAdapters::ConnectionHandler.new
+    end
+
+    module ClassMethods
+      def allocate
+        define_attribute_methods
+        super
+      end
+
+      def initialize_find_by_cache
+        self.find_by_statement_cache = {}.extend(Mutex_m)
+      end
+
+      def inherited(child_class)
+        child_class.initialize_find_by_cache
+        super
+      end
+
+      def find(*ids)
+        # We don't have cache keys for this stuff yet
+        return super unless ids.length == 1
+        return super if block_given? ||
+                        primary_key.nil? ||
+                        default_scopes.any? ||
+                        columns_hash.include?(inheritance_column) ||
+                        ids.first.kind_of?(Array)
+
+        id  = ids.first
+        if ActiveRecord::Base === id
+          id = id.id
+          ActiveSupport::Deprecation.warn "You are passing an instance of ActiveRecord::Base to `find`." \
+            "Please pass the id of the object by calling `.id`"
+        end
+        key = primary_key
+
+        s = find_by_statement_cache[key] || find_by_statement_cache.synchronize {
+          find_by_statement_cache[key] ||= StatementCache.create(connection) { |params|
+            where(key => params.bind).limit(1)
+          }
+        }
+        record = s.execute([id], self, connection).first
+        unless record
+          raise RecordNotFound, "Couldn't find #{name} with '#{primary_key}'=#{id}"
+        end
+        record
+      end
+
+      def find_by(*args)
+        return super if current_scope || args.length > 1 || reflect_on_all_aggregations.any?
+
+        hash = args.first
+
+        return super if hash.values.any? { |v|
+          v.nil? || Array === v || Hash === v
+        }
+
+        key  = hash.keys
+
+        klass = self
+        s = find_by_statement_cache[key] || find_by_statement_cache.synchronize {
+          find_by_statement_cache[key] ||= StatementCache.create(connection) { |params|
+            wheres = key.each_with_object({}) { |param,o|
+              o[param] = params.bind
+            }
+            klass.where(wheres).limit(1)
+          }
+        }
+        begin
+          s.execute(hash.values, self, connection).first
+        rescue TypeError => e
+          raise ActiveRecord::StatementInvalid.new(e.message, e)
+        end
+      end
+
+      def initialize_generated_modules
+        super
+
+        generated_association_methods
+      end
+
+      def generated_association_methods
+        @generated_association_methods ||= begin
+          mod = const_set(:GeneratedAssociationMethods, Module.new)
+          include mod
+          mod
+        end
+      end
+
+      # Returns a string like 'Post(id:integer, title:string, body:text)'
+      def inspect
+        if self == Base
+          super
+        elsif abstract_class?
+          "#{super}(abstract)"
+        elsif !connected?
+          "#{super} (call '#{super}.connection' to establish a connection)"
+        elsif table_exists?
+          attr_list = columns.map { |c| "#{c.name}: #{c.type}" } * ', '
+          "#{super}(#{attr_list})"
+        else
+          "#{super}(Table doesn't exist)"
+        end
+      end
+
+      # Overwrite the default class equality method to provide support for association proxies.
+      def ===(object)
+        object.is_a?(self)
+      end
+
+      # Returns an instance of <tt>Arel::Table</tt> loaded with the current table name.
+      #
+      #   class Post < ActiveRecord::Base
+      #     scope :published_and_commented, -> { published.and(self.arel_table[:comments_count].gt(0)) }
+      #   end
+      def arel_table # :nodoc:
+        @arel_table ||= Arel::Table.new(table_name, arel_engine)
+      end
+
+      # Returns the Arel engine.
+      def arel_engine # :nodoc:
+        @arel_engine ||=
+          if Base == self || connection_handler.retrieve_connection_pool(self)
+            self
+          else
+            superclass.arel_engine
+          end
+      end
+
+      private
+
+      def relation #:nodoc:
+        relation = Relation.create(self, arel_table)
+
+        if finder_needs_type_condition?
+          relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
+        else
+          relation
+        end
+      end
+    end
+
+    # New objects can be instantiated as either empty (pass no construction parameter) or pre-set with
+    # attributes but not yet saved (pass a hash with key names matching the associated table column names).
+    # In both instances, valid attribute keys are determined by the column names of the associated table --
+    # hence you can't have attributes that aren't part of the table columns.
+    #
+    # ==== Example:
+    #   # Instantiates a single new object
+    #   User.new(first_name: 'Jamie')
+    def initialize(attributes = nil, options = {})
+      @attributes = self.class.default_attributes.dup
+
+      init_internals
+      initialize_internals_callback
+
+      self.class.define_attribute_methods
+      # +options+ argument is only needed to make protected_attributes gem easier to hook.
+      # Remove it when we drop support to this gem.
+      init_attributes(attributes, options) if attributes
+
+      yield self if block_given?
+      run_callbacks :initialize unless _initialize_callbacks.empty?
+    end
+
+    # Initialize an empty model object from +coder+. +coder+ must contain
+    # the attributes necessary for initializing an empty model object. For
+    # example:
+    #
+    #   class Post < ActiveRecord::Base
+    #   end
+    #
+    #   post = Post.allocate
+    #   post.init_with('attributes' => { 'title' => 'hello world' })
+    #   post.title # => 'hello world'
+    def init_with(coder)
+      @attributes = coder['attributes']
+
+      init_internals
+
+      @new_record = coder['new_record']
+
+      self.class.define_attribute_methods
+
+      run_callbacks :find
+      run_callbacks :initialize
+
+      self
+    end
+
+    ##
+    # :method: clone
+    # Identical to Ruby's clone method.  This is a "shallow" copy.  Be warned that your attributes are not copied.
+    # That means that modifying attributes of the clone will modify the original, since they will both point to the
+    # same attributes hash. If you need a copy of your attributes hash, please use the #dup method.
+    #
+    #   user = User.first
+    #   new_user = user.clone
+    #   user.name               # => "Bob"
+    #   new_user.name = "Joe"
+    #   user.name               # => "Joe"
+    #
+    #   user.object_id == new_user.object_id            # => false
+    #   user.name.object_id == new_user.name.object_id  # => true
+    #
+    #   user.name.object_id == user.dup.name.object_id  # => false
+
+    ##
+    # :method: dup
+    # Duped objects have no id assigned and are treated as new records. Note
+    # that this is a "shallow" copy as it copies the object's attributes
+    # only, not its associations. The extent of a "deep" copy is application
+    # specific and is therefore left to the application to implement according
+    # to its need.
+    # The dup method does not preserve the timestamps (created|updated)_(at|on).
+
+    ##
+    def initialize_dup(other) # :nodoc:
+      @attributes = @attributes.dup
+      @attributes.reset(self.class.primary_key)
+
+      run_callbacks(:initialize) unless _initialize_callbacks.empty?
+
+      @aggregation_cache = {}
+      @association_cache = {}
+
+      @new_record  = true
+      @destroyed   = false
+
+      super
+    end
+
+    # Populate +coder+ with attributes about this record that should be
+    # serialized. The structure of +coder+ defined in this method is
+    # guaranteed to match the structure of +coder+ passed to the +init_with+
+    # method.
+    #
+    # Example:
+    #
+    #   class Post < ActiveRecord::Base
+    #   end
+    #   coder = {}
+    #   Post.new.encode_with(coder)
+    #   coder # => {"attributes" => {"id" => nil, ... }}
+    def encode_with(coder)
+      # FIXME: Remove this when we better serialize attributes
+      coder['raw_attributes'] = attributes_before_type_cast
+      coder['attributes'] = @attributes
+      coder['new_record'] = new_record?
+    end
+
+    # Returns true if +comparison_object+ is the same exact object, or +comparison_object+
+    # is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
+    #
+    # Note that new records are different from any other record by definition, unless the
+    # other record is the receiver itself. Besides, if you fetch existing records with
+    # +select+ and leave the ID out, you're on your own, this predicate will return false.
+    #
+    # Note also that destroying a record preserves its ID in the model instance, so deleted
+    # models are still comparable.
+    def ==(comparison_object)
+      super ||
+        comparison_object.instance_of?(self.class) &&
+        !id.nil? &&
+        comparison_object.id == id
+    end
+    alias :eql? :==
+
+    # Delegates to id in order to allow two records of the same type and id to work with something like:
+    #   [ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
+    def hash
+      if id
+        id.hash
+      else
+        super
+      end
+    end
+
+    # Clone and freeze the attributes hash such that associations are still
+    # accessible, even on destroyed records, but cloned models will not be
+    # frozen.
+    def freeze
+      @attributes = @attributes.clone.freeze
+      self
+    end
+
+    # Returns +true+ if the attributes hash has been frozen.
+    def frozen?
+      @attributes.frozen?
+    end
+
+    # Allows sort on objects
+    def <=>(other_object)
+      if other_object.is_a?(self.class)
+        self.to_key <=> other_object.to_key
+      else
+        super
+      end
+    end
+
+    # Returns +true+ if the record is read only. Records loaded through joins with piggy-back
+    # attributes will be marked as read only since they cannot be saved.
+    def readonly?
+      @readonly
+    end
+
+    # Marks this record as read only.
+    def readonly!
+      @readonly = true
+    end
+
+    def connection_handler
+      self.class.connection_handler
+    end
+
+    # Returns the contents of the record as a nicely formatted string.
+    def inspect
+      # We check defined?(@attributes) not to issue warnings if the object is
+      # allocated but not initialized.
+      inspection = if defined?(@attributes) && @attributes
+                     self.class.column_names.collect { |name|
+                       if has_attribute?(name)
+                         "#{name}: #{attribute_for_inspect(name)}"
+                       end
+                     }.compact.join(", ")
+                   else
+                     "not initialized"
+                   end
+      "#<#{self.class} #{inspection}>"
+    end
+
+    # Takes a PP and prettily prints this record to it, allowing you to get a nice result from `pp record`
+    # when pp is required.
+    def pretty_print(pp)
+      pp.object_address_group(self) do
+        if defined?(@attributes) && @attributes
+          column_names = self.class.column_names.select { |name| has_attribute?(name) || new_record? }
+          pp.seplist(column_names, proc { pp.text ',' }) do |column_name|
+            column_value = read_attribute(column_name)
+            pp.breakable ' '
+            pp.group(1) do
+              pp.text column_name
+              pp.text ':'
+              pp.breakable
+              pp.pp column_value
+            end
+          end
+        else
+          pp.breakable ' '
+          pp.text 'not initialized'
+        end
+      end
+    end
+
+    # Returns a hash of the given methods with their names as keys and returned values as values.
+    def slice(*methods)
+      Hash[methods.map! { |method| [method, public_send(method)] }].with_indifferent_access
+    end
+
+    def set_transaction_state(state) # :nodoc:
+      @transaction_state = state
+    end
+
+    def has_transactional_callbacks? # :nodoc:
+      !_rollback_callbacks.empty? || !_commit_callbacks.empty? || !_create_callbacks.empty?
+    end
+
+    private
+
+    # Updates the attributes on this particular ActiveRecord object so that
+    # if it is associated with a transaction, then the state of the AR object
+    # will be updated to reflect the current state of the transaction
+    #
+    # The @transaction_state variable stores the states of the associated
+    # transaction. This relies on the fact that a transaction can only be in
+    # one rollback or commit (otherwise a list of states would be required)
+    # Each AR object inside of a transaction carries that transaction's
+    # TransactionState.
+    #
+    # This method checks to see if the ActiveRecord object's state reflects
+    # the TransactionState, and rolls back or commits the ActiveRecord object
+    # as appropriate.
+    #
+    # Since ActiveRecord objects can be inside multiple transactions, this
+    # method recursively goes through the parent of the TransactionState and
+    # checks if the ActiveRecord object reflects the state of the object.
+    def sync_with_transaction_state
+      update_attributes_from_transaction_state(@transaction_state, 0)
+    end
+
+    def update_attributes_from_transaction_state(transaction_state, depth)
+      if transaction_state && transaction_state.finalized? && !has_transactional_callbacks?
+        unless @reflects_state[depth]
+          restore_transaction_record_state if transaction_state.rolledback?
+          clear_transaction_record_state
+          @reflects_state[depth] = true
+        end
+
+        if transaction_state.parent && !@reflects_state[depth+1]
+          update_attributes_from_transaction_state(transaction_state.parent, depth+1)
+        end
+      end
+    end
+
+    # Under Ruby 1.9, Array#flatten will call #to_ary (recursively) on each of the elements
+    # of the array, and then rescues from the possible NoMethodError. If those elements are
+    # ActiveRecord::Base's, then this triggers the various method_missing's that we have,
+    # which significantly impacts upon performance.
+    #
+    # So we can avoid the method_missing hit by explicitly defining #to_ary as nil here.
+    #
+    # See also http://tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary.html
+    def to_ary # :nodoc:
+      nil
+    end
+
+    def init_internals
+      @attributes.ensure_initialized(self.class.primary_key)
+
+      @aggregation_cache        = {}
+      @association_cache        = {}
+      @readonly                 = false
+      @destroyed                = false
+      @marked_for_destruction   = false
+      @destroyed_by_association = nil
+      @new_record               = true
+      @txn                      = nil
+      @_start_transaction_state = {}
+      @transaction_state        = nil
+      @reflects_state           = [false]
+    end
+
+    def initialize_internals_callback
+    end
+
+    # This method is needed to make protected_attributes gem easier to hook.
+    # Remove it when we drop support to this gem.
+    def init_attributes(attributes, options)
+      assign_attributes(attributes)
+    end
+
+    def thaw
+      if frozen?
+        @attributes = @attributes.dup
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
new file mode 100644
index 0000000000..f0b6afc4b4
--- /dev/null
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -0,0 +1,175 @@
+module ActiveRecord
+  # = Active Record Counter Cache
+  module CounterCache
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Resets one or more counter caches to their correct value using an SQL
+      # count query. This is useful when adding new counter caches, or if the
+      # counter has been corrupted or modified directly by SQL.
+      #
+      # ==== Parameters
+      #
+      # * +id+ - The id of the object you wish to reset a counter on.
+      # * +counters+ - One or more association counters to reset. Association name or counter name can be given.
+      #
+      # ==== Examples
+      #
+      #   # For Post with id #1 records reset the comments_count
+      #   Post.reset_counters(1, :comments)
+      def reset_counters(id, *counters)
+        object = find(id)
+        counters.each do |counter_association|
+          has_many_association = _reflect_on_association(counter_association.to_sym)
+          unless has_many_association
+            has_many = reflect_on_all_associations(:has_many)
+            has_many_association = has_many.find { |association| association.counter_cache_column && association.counter_cache_column.to_sym == counter_association.to_sym }
+            counter_association = has_many_association.plural_name if has_many_association
+          end
+          raise ArgumentError, "'#{self.name}' has no association called '#{counter_association}'" unless has_many_association
+
+          if has_many_association.is_a? ActiveRecord::Reflection::ThroughReflection
+            has_many_association = has_many_association.through_reflection
+          end
+
+          foreign_key  = has_many_association.foreign_key.to_s
+          child_class  = has_many_association.klass
+          reflection   = child_class._reflections.values.find { |e| e.belongs_to? && e.foreign_key.to_s == foreign_key && e.options[:counter_cache].present? }
+          counter_name = reflection.counter_cache_column
+
+          stmt = unscoped.where(arel_table[primary_key].eq(object.id)).arel.compile_update({
+            arel_table[counter_name] => object.send(counter_association).count(:all)
+          }, primary_key)
+          connection.update stmt
+        end
+        return true
+      end
+
+      # A generic "counter updater" implementation, intended primarily to be
+      # used by increment_counter and decrement_counter, but which may also
+      # be useful on its own. It simply does a direct SQL update for the record
+      # with the given ID, altering the given hash of counters by the amount
+      # given by the corresponding value:
+      #
+      # ==== Parameters
+      #
+      # * +id+ - The id of the object you wish to update a counter on or an Array of ids.
+      # * +counters+ - A Hash containing the names of the fields
+      #   to update as keys and the amount to update the field by as values.
+      #
+      # ==== Examples
+      #
+      #   # For the Post with id of 5, decrement the comment_count by 1, and
+      #   # increment the action_count by 1
+      #   Post.update_counters 5, comment_count: -1, action_count: 1
+      #   # Executes the following SQL:
+      #   # UPDATE posts
+      #   #    SET comment_count = COALESCE(comment_count, 0) - 1,
+      #   #        action_count = COALESCE(action_count, 0) + 1
+      #   #  WHERE id = 5
+      #
+      #   # For the Posts with id of 10 and 15, increment the comment_count by 1
+      #   Post.update_counters [10, 15], comment_count: 1
+      #   # Executes the following SQL:
+      #   # UPDATE posts
+      #   #    SET comment_count = COALESCE(comment_count, 0) + 1
+      #   #  WHERE id IN (10, 15)
+      def update_counters(id, counters)
+        updates = counters.map do |counter_name, value|
+          operator = value < 0 ? '-' : '+'
+          quoted_column = connection.quote_column_name(counter_name)
+          "#{quoted_column} = COALESCE(#{quoted_column}, 0) #{operator} #{value.abs}"
+        end
+
+        unscoped.where(primary_key => id).update_all updates.join(', ')
+      end
+
+      # Increment a numeric field by one, via a direct SQL update.
+      #
+      # This method is used primarily for maintaining counter_cache columns that are
+      # used to store aggregate values. For example, a DiscussionBoard may cache
+      # posts_count and comments_count to avoid running an SQL query to calculate the
+      # number of posts and comments there are, each time it is displayed.
+      #
+      # ==== Parameters
+      #
+      # * +counter_name+ - The name of the field that should be incremented.
+      # * +id+ - The id of the object that should be incremented or an Array of ids.
+      #
+      # ==== Examples
+      #
+      #   # Increment the post_count column for the record with an id of 5
+      #   DiscussionBoard.increment_counter(:post_count, 5)
+      def increment_counter(counter_name, id)
+        update_counters(id, counter_name => 1)
+      end
+
+      # Decrement a numeric field by one, via a direct SQL update.
+      #
+      # This works the same as increment_counter but reduces the column value by
+      # 1 instead of increasing it.
+      #
+      # ==== Parameters
+      #
+      # * +counter_name+ - The name of the field that should be decremented.
+      # * +id+ - The id of the object that should be decremented or an Array of ids.
+      #
+      # ==== Examples
+      #
+      #   # Decrement the post_count column for the record with an id of 5
+      #   DiscussionBoard.decrement_counter(:post_count, 5)
+      def decrement_counter(counter_name, id)
+        update_counters(id, counter_name => -1)
+      end
+    end
+
+    protected
+
+      def actually_destroyed?
+        @_actually_destroyed
+      end
+
+      def clear_destroy_state
+        @_actually_destroyed = nil
+      end
+
+    private
+
+      def _create_record(*)
+        id = super
+
+        each_counter_cached_associations do |association|
+          if send(association.reflection.name)
+            association.increment_counters
+            @_after_create_counter_called = true
+          end
+        end
+
+        id
+      end
+
+      def destroy_row
+        affected_rows = super
+
+        if affected_rows > 0
+          each_counter_cached_associations do |association|
+            foreign_key = association.reflection.foreign_key.to_sym
+            unless destroyed_by_association && destroyed_by_association.foreign_key.to_sym == foreign_key
+              if send(association.reflection.name)
+                association.decrement_counters
+              end
+            end
+          end
+        end
+
+        affected_rows
+      end
+
+      def each_counter_cached_associations
+        _reflections.each do |name, reflection|
+          yield association(name) if reflection.belongs_to? && reflection.counter_cache_column
+        end
+      end
+
+  end
+end
diff --git a/activerecord/lib/active_record/dynamic_matchers.rb b/activerecord/lib/active_record/dynamic_matchers.rb
new file mode 100644
index 0000000000..e94b74063e
--- /dev/null
+++ b/activerecord/lib/active_record/dynamic_matchers.rb
@@ -0,0 +1,140 @@
+module ActiveRecord
+  module DynamicMatchers #:nodoc:
+    # This code in this file seems to have a lot of indirection, but the indirection
+    # is there to provide extension points for the activerecord-deprecated_finders
+    # gem. When we stop supporting activerecord-deprecated_finders (from Rails 5),
+    # then we can remove the indirection.
+
+    def respond_to?(name, include_private = false)
+      if self == Base
+        super
+      else
+        match = Method.match(self, name)
+        match && match.valid? || super
+      end
+    end
+
+    private
+
+    def method_missing(name, *arguments, &block)
+      match = Method.match(self, name)
+
+      if match && match.valid?
+        match.define
+        send(name, *arguments, &block)
+      else
+        super
+      end
+    end
+
+    class Method
+      @matchers = []
+
+      class << self
+        attr_reader :matchers
+
+        def match(model, name)
+          klass = matchers.find { |k| name =~ k.pattern }
+          klass.new(model, name) if klass
+        end
+
+        def pattern
+          @pattern ||= /\A#{prefix}_([_a-zA-Z]\w*)#{suffix}\Z/
+        end
+
+        def prefix
+          raise NotImplementedError
+        end
+
+        def suffix
+          ''
+        end
+      end
+
+      attr_reader :model, :name, :attribute_names
+
+      def initialize(model, name)
+        @model           = model
+        @name            = name.to_s
+        @attribute_names = @name.match(self.class.pattern)[1].split('_and_')
+        @attribute_names.map! { |n| @model.attribute_aliases[n] || n }
+      end
+
+      def valid?
+        attribute_names.all? { |name| model.columns_hash[name] || model.reflect_on_aggregation(name.to_sym) }
+      end
+
+      def define
+        model.class_eval <<-CODE, __FILE__, __LINE__ + 1
+          def self.#{name}(#{signature})
+            #{body}
+          end
+        CODE
+      end
+
+      def body
+        raise NotImplementedError
+      end
+    end
+
+    module Finder
+      # Extended in activerecord-deprecated_finders
+      def body
+        result
+      end
+
+      # Extended in activerecord-deprecated_finders
+      def result
+        "#{finder}(#{attributes_hash})"
+      end
+
+      # The parameters in the signature may have reserved Ruby words, in order
+      # to prevent errors, we start each param name with `_`.
+      #
+      # Extended in activerecord-deprecated_finders
+      def signature
+        attribute_names.map { |name| "_#{name}" }.join(', ')
+      end
+
+      # Given that the parameters starts with `_`, the finder needs to use the
+      # same parameter name.
+      def attributes_hash
+        "{" + attribute_names.map { |name| ":#{name} => _#{name}" }.join(',') + "}"
+      end
+
+      def finder
+        raise NotImplementedError
+      end
+    end
+
+    class FindBy < Method
+      Method.matchers << self
+      include Finder
+
+      def self.prefix
+        "find_by"
+      end
+
+      def finder
+        "find_by"
+      end
+    end
+
+    class FindByBang < Method
+      Method.matchers << self
+      include Finder
+
+      def self.prefix
+        "find_by"
+      end
+
+      def self.suffix
+        "!"
+      end
+
+      def finder
+        "find_by!"
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/enum.rb b/activerecord/lib/active_record/enum.rb
new file mode 100644
index 0000000000..f0ee433d0b
--- /dev/null
+++ b/activerecord/lib/active_record/enum.rb
@@ -0,0 +1,198 @@
+require 'active_support/core_ext/object/deep_dup'
+
+module ActiveRecord
+  # Declare an enum attribute where the values map to integers in the database,
+  # but can be queried by name. Example:
+  #
+  #   class Conversation < ActiveRecord::Base
+  #     enum status: [ :active, :archived ]
+  #   end
+  #
+  #   # conversation.update! status: 0
+  #   conversation.active!
+  #   conversation.active? # => true
+  #   conversation.status  # => "active"
+  #
+  #   # conversation.update! status: 1
+  #   conversation.archived!
+  #   conversation.archived? # => true
+  #   conversation.status    # => "archived"
+  #
+  #   # conversation.update! status: 1
+  #   conversation.status = "archived"
+  #
+  #   # conversation.update! status: nil
+  #   conversation.status = nil
+  #   conversation.status.nil? # => true
+  #   conversation.status      # => nil
+  #
+  # Scopes based on the allowed values of the enum field will be provided
+  # as well. With the above example:
+  #
+  #   Conversation.active
+  #   Conversation.archived
+  #
+  # You can set the default value from the database declaration, like:
+  #
+  #   create_table :conversations do |t|
+  #     t.column :status, :integer, default: 0
+  #   end
+  #
+  # Good practice is to let the first declared status be the default.
+  #
+  # Finally, it's also possible to explicitly map the relation between attribute and
+  # database integer with a +Hash+:
+  #
+  #   class Conversation < ActiveRecord::Base
+  #     enum status: { active: 0, archived: 1 }
+  #   end
+  #
+  # Note that when an +Array+ is used, the implicit mapping from the values to database
+  # integers is derived from the order the values appear in the array. In the example,
+  # <tt>:active</tt> is mapped to +0+ as it's the first element, and <tt>:archived</tt>
+  # is mapped to +1+. In general, the +i+-th element is mapped to <tt>i-1</tt> in the
+  # database.
+  #
+  # Therefore, once a value is added to the enum array, its position in the array must
+  # be maintained, and new values should only be added to the end of the array. To
+  # remove unused values, the explicit +Hash+ syntax should be used.
+  #
+  # In rare circumstances you might need to access the mapping directly.
+  # The mappings are exposed through a class method with the pluralized attribute
+  # name:
+  #
+  #   Conversation.statuses # => { "active" => 0, "archived" => 1 }
+  #
+  # Use that class method when you need to know the ordinal value of an enum:
+  #
+  #   Conversation.where("status <> ?", Conversation.statuses[:archived])
+  #
+  # Where conditions on an enum attribute must use the ordinal value of an enum.
+  module Enum
+    def self.extended(base) # :nodoc:
+      base.class_attribute(:defined_enums)
+      base.defined_enums = {}
+    end
+
+    def inherited(base) # :nodoc:
+      base.defined_enums = defined_enums.deep_dup
+      super
+    end
+
+    def enum(definitions)
+      klass = self
+      definitions.each do |name, values|
+        # statuses = { }
+        enum_values = ActiveSupport::HashWithIndifferentAccess.new
+        name        = name.to_sym
+
+        # def self.statuses statuses end
+        detect_enum_conflict!(name, name.to_s.pluralize, true)
+        klass.singleton_class.send(:define_method, name.to_s.pluralize) { enum_values }
+
+        _enum_methods_module.module_eval do
+          # def status=(value) self[:status] = statuses[value] end
+          klass.send(:detect_enum_conflict!, name, "#{name}=")
+          define_method("#{name}=") { |value|
+            if enum_values.has_key?(value) || value.blank?
+              self[name] = enum_values[value]
+            elsif enum_values.has_value?(value)
+              # Assigning a value directly is not a end-user feature, hence it's not documented.
+              # This is used internally to make building objects from the generated scopes work
+              # as expected, i.e. +Conversation.archived.build.archived?+ should be true.
+              self[name] = value
+            else
+              raise ArgumentError, "'#{value}' is not a valid #{name}"
+            end
+          }
+
+          # def status() statuses.key self[:status] end
+          klass.send(:detect_enum_conflict!, name, name)
+          define_method(name) { enum_values.key self[name] }
+
+          # def status_before_type_cast() statuses.key self[:status] end
+          klass.send(:detect_enum_conflict!, name, "#{name}_before_type_cast")
+          define_method("#{name}_before_type_cast") { enum_values.key self[name] }
+
+          pairs = values.respond_to?(:each_pair) ? values.each_pair : values.each_with_index
+          pairs.each do |value, i|
+            enum_values[value] = i
+
+            # def active?() status == 0 end
+            klass.send(:detect_enum_conflict!, name, "#{value}?")
+            define_method("#{value}?") { self[name] == i }
+
+            # def active!() update! status: :active end
+            klass.send(:detect_enum_conflict!, name, "#{value}!")
+            define_method("#{value}!") { update! name => value }
+
+            # scope :active, -> { where status: 0 }
+            klass.send(:detect_enum_conflict!, name, value, true)
+            klass.scope value, -> { klass.where name => i }
+          end
+        end
+        defined_enums[name.to_s] = enum_values
+      end
+    end
+
+    private
+      def _enum_methods_module
+        @_enum_methods_module ||= begin
+          mod = Module.new do
+            private
+              def save_changed_attribute(attr_name, old)
+                if (mapping = self.class.defined_enums[attr_name.to_s])
+                  value = read_attribute(attr_name)
+                  if attribute_changed?(attr_name)
+                    if mapping[old] == value
+                      changed_attributes.delete(attr_name)
+                    end
+                  else
+                    if old != value
+                      changed_attributes[attr_name] = mapping.key old
+                    end
+                  end
+                else
+                  super
+                end
+              end
+          end
+          include mod
+          mod
+        end
+      end
+
+      ENUM_CONFLICT_MESSAGE = \
+        "You tried to define an enum named \"%{enum}\" on the model \"%{klass}\", but " \
+        "this will generate a %{type} method \"%{method}\", which is already defined " \
+        "by %{source}."
+
+      def detect_enum_conflict!(enum_name, method_name, klass_method = false)
+        if klass_method && dangerous_class_method?(method_name)
+          raise ArgumentError, ENUM_CONFLICT_MESSAGE % {
+            enum: enum_name,
+            klass: self.name,
+            type: 'class',
+            method: method_name,
+            source: 'Active Record'
+          }
+        elsif !klass_method && dangerous_attribute_method?(method_name)
+          raise ArgumentError, ENUM_CONFLICT_MESSAGE % {
+            enum: enum_name,
+            klass: self.name,
+            type: 'instance',
+            method: method_name,
+            source: 'Active Record'
+          }
+        elsif !klass_method && method_defined_within?(method_name, _enum_methods_module, Module)
+          raise ArgumentError, ENUM_CONFLICT_MESSAGE % {
+            enum: enum_name,
+            klass: self.name,
+            type: 'instance',
+            method: method_name,
+            source: 'another enum'
+          }
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/errors.rb b/activerecord/lib/active_record/errors.rb
new file mode 100644
index 0000000000..52c70977ef
--- /dev/null
+++ b/activerecord/lib/active_record/errors.rb
@@ -0,0 +1,231 @@
+module ActiveRecord
+
+  # = Active Record Errors
+  #
+  # Generic Active Record exception class.
+  class ActiveRecordError < StandardError
+  end
+
+  # Raised when the single-table inheritance mechanism fails to locate the subclass
+  # (for example due to improper usage of column that +inheritance_column+ points to).
+  class SubclassNotFound < ActiveRecordError #:nodoc:
+  end
+
+  # Raised when an object assigned to an association has an incorrect type.
+  #
+  #   class Ticket < ActiveRecord::Base
+  #     has_many :patches
+  #   end
+  #
+  #   class Patch < ActiveRecord::Base
+  #     belongs_to :ticket
+  #   end
+  #
+  #   # Comments are not patches, this assignment raises AssociationTypeMismatch.
+  #   @ticket.patches << Comment.new(content: "Please attach tests to your patch.")
+  class AssociationTypeMismatch < ActiveRecordError
+  end
+
+  # Raised when unserialized object's type mismatches one specified for serializable field.
+  class SerializationTypeMismatch < ActiveRecordError
+  end
+
+  # Raised when adapter not specified on connection (or configuration file
+  # +config/database.yml+ misses adapter field).
+  class AdapterNotSpecified < ActiveRecordError
+  end
+
+  # Raised when Active Record cannot find database adapter specified in
+  # +config/database.yml+ or programmatically.
+  class AdapterNotFound < ActiveRecordError
+  end
+
+  # Raised when connection to the database could not been established (for
+  # example when +connection=+ is given a nil object).
+  class ConnectionNotEstablished < ActiveRecordError
+  end
+
+  # Raised when Active Record cannot find record by given id or set of ids.
+  class RecordNotFound < ActiveRecordError
+  end
+
+  # Raised by ActiveRecord::Base.save! and ActiveRecord::Base.create! methods when record cannot be
+  # saved because record is invalid.
+  class RecordNotSaved < ActiveRecordError
+  end
+
+  # Raised by ActiveRecord::Base.destroy! when a call to destroy would return false.
+  class RecordNotDestroyed < ActiveRecordError
+  end
+
+  # Superclass for all database execution errors.
+  #
+  # Wraps the underlying database error as +original_exception+.
+  class StatementInvalid < ActiveRecordError
+    attr_reader :original_exception
+
+    def initialize(message, original_exception = nil)
+      super(message)
+      @original_exception = original_exception
+    end
+  end
+
+  # Defunct wrapper class kept for compatibility.
+  # +StatementInvalid+ wraps the original exception now.
+  class WrappedDatabaseException < StatementInvalid
+  end
+
+  # Raised when a record cannot be inserted because it would violate a uniqueness constraint.
+  class RecordNotUnique < WrappedDatabaseException
+  end
+
+  # Raised when a record cannot be inserted or updated because it references a non-existent record.
+  class InvalidForeignKey < WrappedDatabaseException
+  end
+
+  # Raised when number of bind variables in statement given to +:condition+ key
+  # (for example, when using +find+ method) does not match number of expected
+  # values supplied.
+  #
+  # For example, when there are two placeholders with only one value supplied:
+  #
+  #   Location.where("lat = ? AND lng = ?", 53.7362)
+  class PreparedStatementInvalid < ActiveRecordError
+  end
+
+  # Raised when a given database does not exist.
+  class NoDatabaseError < StatementInvalid
+  end
+
+  # Raised on attempt to save stale record. Record is stale when it's being saved in another query after
+  # instantiation, for example, when two users edit the same wiki page and one starts editing and saves
+  # the page before the other.
+  #
+  # Read more about optimistic locking in ActiveRecord::Locking module
+  # documentation.
+  class StaleObjectError < ActiveRecordError
+    attr_reader :record, :attempted_action
+
+    def initialize(record, attempted_action)
+      super("Attempted to #{attempted_action} a stale object: #{record.class.name}")
+      @record = record
+      @attempted_action = attempted_action
+    end
+
+  end
+
+  # Raised when association is being configured improperly or user tries to use
+  # offset and limit together with +has_many+ or +has_and_belongs_to_many+
+  # associations.
+  class ConfigurationError < ActiveRecordError
+  end
+
+  # Raised on attempt to update record that is instantiated as read only.
+  class ReadOnlyRecord < ActiveRecordError
+  end
+
+  # ActiveRecord::Transactions::ClassMethods.transaction uses this exception
+  # to distinguish a deliberate rollback from other exceptional situations.
+  # Normally, raising an exception will cause the +transaction+ method to rollback
+  # the database transaction *and* pass on the exception. But if you raise an
+  # ActiveRecord::Rollback exception, then the database transaction will be rolled back,
+  # without passing on the exception.
+  #
+  # For example, you could do this in your controller to rollback a transaction:
+  #
+  #   class BooksController < ActionController::Base
+  #     def create
+  #       Book.transaction do
+  #         book = Book.new(params[:book])
+  #         book.save!
+  #         if today_is_friday?
+  #           # The system must fail on Friday so that our support department
+  #           # won't be out of job. We silently rollback this transaction
+  #           # without telling the user.
+  #           raise ActiveRecord::Rollback, "Call tech support!"
+  #         end
+  #       end
+  #       # ActiveRecord::Rollback is the only exception that won't be passed on
+  #       # by ActiveRecord::Base.transaction, so this line will still be reached
+  #       # even on Friday.
+  #       redirect_to root_url
+  #     end
+  #   end
+  class Rollback < ActiveRecordError
+  end
+
+  # Raised when attribute has a name reserved by Active Record (when attribute
+  # has name of one of Active Record instance methods).
+  class DangerousAttributeError < ActiveRecordError
+  end
+
+  # Raised when unknown attributes are supplied via mass assignment.
+  class UnknownAttributeError < NoMethodError
+
+    attr_reader :record, :attribute
+
+    def initialize(record, attribute)
+      @record = record
+      @attribute = attribute.to_s
+      super("unknown attribute: #{attribute}")
+    end
+
+  end
+
+  # Raised when an error occurred while doing a mass assignment to an attribute through the
+  # +attributes=+ method. The exception has an +attribute+ property that is the name of the
+  # offending attribute.
+  class AttributeAssignmentError < ActiveRecordError
+    attr_reader :exception, :attribute
+    def initialize(message, exception, attribute)
+      super(message)
+      @exception = exception
+      @attribute = attribute
+    end
+  end
+
+  # Raised when there are multiple errors while doing a mass assignment through the +attributes+
+  # method. The exception has an +errors+ property that contains an array of AttributeAssignmentError
+  # objects, each corresponding to the error while assigning to an attribute.
+  class MultiparameterAssignmentErrors < ActiveRecordError
+    attr_reader :errors
+    def initialize(errors)
+      @errors = errors
+    end
+  end
+
+  # Raised when a primary key is needed, but not specified in the schema or model.
+  class UnknownPrimaryKey < ActiveRecordError
+    attr_reader :model
+
+    def initialize(model)
+      super("Unknown primary key for table #{model.table_name} in model #{model}.")
+      @model = model
+    end
+
+  end
+
+  # Raised when a relation cannot be mutated because it's already loaded.
+  #
+  #   class Task < ActiveRecord::Base
+  #   end
+  #
+  #   relation = Task.all
+  #   relation.loaded? # => true
+  #
+  #   # Methods which try to mutate a loaded relation fail.
+  #   relation.where!(title: 'TODO')  # => ActiveRecord::ImmutableRelation
+  #   relation.limit!(5)              # => ActiveRecord::ImmutableRelation
+  class ImmutableRelation < ActiveRecordError
+  end
+
+  # TransactionIsolationError will be raised under the following conditions:
+  #
+  # * The adapter does not support setting the isolation level
+  # * You are joining an existing open transaction
+  # * You are creating a nested (savepoint) transaction
+  #
+  # The mysql, mysql2 and postgresql adapters support setting the transaction isolation level.
+  class TransactionIsolationError < ActiveRecordError
+  end
+end
diff --git a/activerecord/lib/active_record/explain.rb b/activerecord/lib/active_record/explain.rb
new file mode 100644
index 0000000000..727a9befc1
--- /dev/null
+++ b/activerecord/lib/active_record/explain.rb
@@ -0,0 +1,38 @@
+require 'active_support/lazy_load_hooks'
+require 'active_record/explain_registry'
+
+module ActiveRecord
+  module Explain
+    # Executes the block with the collect flag enabled. Queries are collected
+    # asynchronously by the subscriber and returned.
+    def collecting_queries_for_explain # :nodoc:
+      ExplainRegistry.collect = true
+      yield
+      ExplainRegistry.queries
+    ensure
+      ExplainRegistry.reset
+    end
+
+    # Makes the adapter execute EXPLAIN for the tuples of queries and bindings.
+    # Returns a formatted string ready to be logged.
+    def exec_explain(queries) # :nodoc:
+      str = queries.map do |sql, bind|
+        [].tap do |msg|
+          msg << "EXPLAIN for: #{sql}"
+          unless bind.empty?
+            bind_msg = bind.map {|col, val| [col.name, val]}.inspect
+            msg.last << " #{bind_msg}"
+          end
+          msg << connection.explain(sql, bind)
+        end.join("\n")
+      end.join("\n")
+
+      # Overriding inspect to be more human readable, especially in the console.
+      def str.inspect
+        self
+      end
+
+      str
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/explain_registry.rb b/activerecord/lib/active_record/explain_registry.rb
new file mode 100644
index 0000000000..f5cd57e075
--- /dev/null
+++ b/activerecord/lib/active_record/explain_registry.rb
@@ -0,0 +1,30 @@
+require 'active_support/per_thread_registry'
+
+module ActiveRecord
+  # This is a thread locals registry for EXPLAIN. For example
+  #
+  #   ActiveRecord::ExplainRegistry.queries
+  #
+  # returns the collected queries local to the current thread.
+  #
+  # See the documentation of <tt>ActiveSupport::PerThreadRegistry</tt>
+  # for further details.
+  class ExplainRegistry # :nodoc:
+    extend ActiveSupport::PerThreadRegistry
+
+    attr_accessor :queries, :collect
+
+    def initialize
+      reset
+    end
+
+    def collect?
+      @collect
+    end
+
+    def reset
+      @collect = false
+      @queries = []
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/explain_subscriber.rb b/activerecord/lib/active_record/explain_subscriber.rb
new file mode 100644
index 0000000000..6a49936644
--- /dev/null
+++ b/activerecord/lib/active_record/explain_subscriber.rb
@@ -0,0 +1,29 @@
+require 'active_support/notifications'
+require 'active_record/explain_registry'
+
+module ActiveRecord
+  class ExplainSubscriber # :nodoc:
+    def start(name, id, payload)
+      # unused
+    end
+
+    def finish(name, id, payload)
+      if ExplainRegistry.collect? && !ignore_payload?(payload)
+        ExplainRegistry.queries << payload.values_at(:sql, :binds)
+      end
+    end
+
+    # SCHEMA queries cannot be EXPLAINed, also we do not want to run EXPLAIN on
+    # our own EXPLAINs now matter how loopingly beautiful that would be.
+    #
+    # On the other hand, we want to monitor the performance of our real database
+    # queries, not the performance of the access to the query cache.
+    IGNORED_PAYLOADS = %w(SCHEMA EXPLAIN CACHE)
+    EXPLAINED_SQLS = /\A\s*(select|update|delete|insert)\b/i
+    def ignore_payload?(payload)
+      payload[:exception] || IGNORED_PAYLOADS.include?(payload[:name]) || payload[:sql] !~ EXPLAINED_SQLS
+    end
+
+    ActiveSupport::Notifications.subscribe("sql.active_record", new)
+  end
+end
diff --git a/activerecord/lib/active_record/fixture_set/file.rb b/activerecord/lib/active_record/fixture_set/file.rb
new file mode 100644
index 0000000000..8132310c91
--- /dev/null
+++ b/activerecord/lib/active_record/fixture_set/file.rb
@@ -0,0 +1,56 @@
+require 'erb'
+require 'yaml'
+
+module ActiveRecord
+  class FixtureSet
+    class File # :nodoc:
+      include Enumerable
+
+      ##
+      # Open a fixture file named +file+.  When called with a block, the block
+      # is called with the filehandle and the filehandle is automatically closed
+      # when the block finishes.
+      def self.open(file)
+        x = new file
+        block_given? ? yield(x) : x
+      end
+
+      def initialize(file)
+        @file = file
+        @rows = nil
+      end
+
+      def each(&block)
+        rows.each(&block)
+      end
+
+
+      private
+        def rows
+          return @rows if @rows
+
+          begin
+            data = YAML.load(render(IO.read(@file)))
+          rescue ArgumentError, Psych::SyntaxError => error
+            raise Fixture::FormatError, "a YAML error occurred parsing #{@file}. Please note that YAML must be consistently indented using spaces. Tabs are not allowed. Please have a look at http://www.yaml.org/faq.html\nThe exact error was:\n  #{error.class}: #{error}", error.backtrace
+          end
+          @rows = data ? validate(data).to_a : []
+        end
+
+        def render(content)
+          context = ActiveRecord::FixtureSet::RenderContext.create_subclass.new
+          ERB.new(content).result(context.get_binding)
+        end
+
+        # Validate our unmarshalled data.
+        def validate(data)
+          unless Hash === data || YAML::Omap === data
+            raise Fixture::FormatError, 'fixture is not a hash'
+          end
+
+          raise Fixture::FormatError unless data.all? { |name, row| Hash === row }
+          data
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
new file mode 100644
index 0000000000..4306b36ae1
--- /dev/null
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -0,0 +1,1030 @@
+require 'erb'
+require 'yaml'
+require 'zlib'
+require 'active_support/dependencies'
+require 'active_support/core_ext/digest/uuid'
+require 'active_record/fixture_set/file'
+require 'active_record/errors'
+
+module ActiveRecord
+  class FixtureClassNotFound < ActiveRecord::ActiveRecordError #:nodoc:
+  end
+
+  # \Fixtures are a way of organizing data that you want to test against; in short, sample data.
+  #
+  # They are stored in YAML files, one file per model, which are placed in the directory
+  # appointed by <tt>ActiveSupport::TestCase.fixture_path=(path)</tt> (this is automatically
+  # configured for Rails, so you can just put your files in <tt><your-rails-app>/test/fixtures/</tt>).
+  # The fixture file ends with the +.yml+ file extension, for example:
+  # <tt><your-rails-app>/test/fixtures/web_sites.yml</tt>).
+  #
+  # The format of a fixture file looks like this:
+  #
+  #   rubyonrails:
+  #     id: 1
+  #     name: Ruby on Rails
+  #     url: http://www.rubyonrails.org
+  #
+  #   google:
+  #     id: 2
+  #     name: Google
+  #     url: http://www.google.com
+  #
+  # This fixture file includes two fixtures. Each YAML fixture (ie. record) is given a name and
+  # is followed by an indented list of key/value pairs in the "key: value" format. Records are
+  # separated by a blank line for your viewing pleasure.
+  #
+  # Note: Fixtures are unordered. If you want ordered fixtures, use the omap YAML type.
+  # See http://yaml.org/type/omap.html
+  # for the specification. You will need ordered fixtures when you have foreign key constraints
+  # on keys in the same table. This is commonly needed for tree structures. Example:
+  #
+  #    --- !omap
+  #    - parent:
+  #        id:         1
+  #        parent_id:  NULL
+  #        title:      Parent
+  #    - child:
+  #        id:         2
+  #        parent_id:  1
+  #        title:      Child
+  #
+  # = Using Fixtures in Test Cases
+  #
+  # Since fixtures are a testing construct, we use them in our unit and functional tests. There
+  # are two ways to use the fixtures, but first let's take a look at a sample unit test:
+  #
+  #   require 'test_helper'
+  #
+  #   class WebSiteTest < ActiveSupport::TestCase
+  #     test "web_site_count" do
+  #       assert_equal 2, WebSite.count
+  #     end
+  #   end
+  #
+  # By default, +test_helper.rb+ will load all of your fixtures into your test
+  # database, so this test will succeed.
+  #
+  # The testing environment will automatically load the all fixtures into the database before each
+  # test. To ensure consistent data, the environment deletes the fixtures before running the load.
+  #
+  # In addition to being available in the database, the fixture's data may also be accessed by
+  # using a special dynamic method, which has the same name as the model, and accepts the
+  # name of the fixture to instantiate:
+  #
+  #   test "find" do
+  #     assert_equal "Ruby on Rails", web_sites(:rubyonrails).name
+  #   end
+  #
+  # Alternatively, you may enable auto-instantiation of the fixture data. For instance, take the
+  # following tests:
+  #
+  #   test "find_alt_method_1" do
+  #     assert_equal "Ruby on Rails", @web_sites['rubyonrails']['name']
+  #   end
+  #
+  #   test "find_alt_method_2" do
+  #     assert_equal "Ruby on Rails", @rubyonrails.name
+  #   end
+  #
+  # In order to use these methods to access fixtured data within your testcases, you must specify one of the
+  # following in your <tt>ActiveSupport::TestCase</tt>-derived class:
+  #
+  # - to fully enable instantiated fixtures (enable alternate methods #1 and #2 above)
+  #     self.use_instantiated_fixtures = true
+  #
+  # - create only the hash for the fixtures, do not 'find' each instance (enable alternate method #1 only)
+  #     self.use_instantiated_fixtures = :no_instances
+  #
+  # Using either of these alternate methods incurs a performance hit, as the fixtured data must be fully
+  # traversed in the database to create the fixture hash and/or instance variables. This is expensive for
+  # large sets of fixtured data.
+  #
+  # = Dynamic fixtures with ERB
+  #
+  # Some times you don't care about the content of the fixtures as much as you care about the volume.
+  # In these cases, you can mix ERB in with your YAML fixtures to create a bunch of fixtures for load
+  # testing, like:
+  #
+  #   <% 1.upto(1000) do |i| %>
+  #   fix_<%= i %>:
+  #     id: <%= i %>
+  #     name: guy_<%= 1 %>
+  #   <% end %>
+  #
+  # This will create 1000 very simple fixtures.
+  #
+  # Using ERB, you can also inject dynamic values into your fixtures with inserts like
+  # <tt><%= Date.today.strftime("%Y-%m-%d") %></tt>.
+  # This is however a feature to be used with some caution. The point of fixtures are that they're
+  # stable units of predictable sample data. If you feel that you need to inject dynamic values, then
+  # perhaps you should reexamine whether your application is properly testable. Hence, dynamic values
+  # in fixtures are to be considered a code smell.
+  #
+  # Helper methods defined in a fixture will not be available in other fixtures, to prevent against
+  # unwanted inter-test dependencies. Methods used by multiple fixtures should be defined in a module
+  # that is included in <tt>ActiveRecord::FixtureSet.context_class</tt>.
+  #
+  # - define a helper method in `test_helper.rb`
+  #     class FixtureFileHelpers
+  #       def file_sha(path)
+  #         Digest::SHA2.hexdigest(File.read(Rails.root.join('test/fixtures', path)))
+  #       end
+  #     end
+  #     ActiveRecord::FixtureSet.context_class.send :include, FixtureFileHelpers
+  #
+  # - use the helper method in a fixture
+  #     photo:
+  #       name: kitten.png
+  #       sha: <%= file_sha 'files/kitten.png' %>
+  #
+  # = Transactional Fixtures
+  #
+  # Test cases can use begin+rollback to isolate their changes to the database instead of having to
+  # delete+insert for every test case.
+  #
+  #   class FooTest < ActiveSupport::TestCase
+  #     self.use_transactional_fixtures = true
+  #
+  #     test "godzilla" do
+  #       assert !Foo.all.empty?
+  #       Foo.destroy_all
+  #       assert Foo.all.empty?
+  #     end
+  #
+  #     test "godzilla aftermath" do
+  #       assert !Foo.all.empty?
+  #     end
+  #   end
+  #
+  # If you preload your test database with all fixture data (probably in the rake task) and use
+  # transactional fixtures, then you may omit all fixtures declarations in your test cases since
+  # all the data's already there and every case rolls back its changes.
+  #
+  # In order to use instantiated fixtures with preloaded data, set +self.pre_loaded_fixtures+ to
+  # true. This will provide access to fixture data for every table that has been loaded through
+  # fixtures (depending on the value of +use_instantiated_fixtures+).
+  #
+  # When *not* to use transactional fixtures:
+  #
+  # 1. You're testing whether a transaction works correctly. Nested transactions don't commit until
+  #    all parent transactions commit, particularly, the fixtures transaction which is begun in setup
+  #    and rolled back in teardown. Thus, you won't be able to verify
+  #    the results of your transaction until Active Record supports nested transactions or savepoints (in progress).
+  # 2. Your database does not support transactions. Every Active Record database supports transactions except MySQL MyISAM.
+  #    Use InnoDB, MaxDB, or NDB instead.
+  #
+  # = Advanced Fixtures
+  #
+  # Fixtures that don't specify an ID get some extra features:
+  #
+  # * Stable, autogenerated IDs
+  # * Label references for associations (belongs_to, has_one, has_many)
+  # * HABTM associations as inline lists
+  # * Autofilled timestamp columns
+  # * Fixture label interpolation
+  # * Support for YAML defaults
+  #
+  # == Stable, Autogenerated IDs
+  #
+  # Here, have a monkey fixture:
+  #
+  #   george:
+  #     id: 1
+  #     name: George the Monkey
+  #
+  #   reginald:
+  #     id: 2
+  #     name: Reginald the Pirate
+  #
+  # Each of these fixtures has two unique identifiers: one for the database
+  # and one for the humans. Why don't we generate the primary key instead?
+  # Hashing each fixture's label yields a consistent ID:
+  #
+  #   george: # generated id: 503576764
+  #     name: George the Monkey
+  #
+  #   reginald: # generated id: 324201669
+  #     name: Reginald the Pirate
+  #
+  # Active Record looks at the fixture's model class, discovers the correct
+  # primary key, and generates it right before inserting the fixture
+  # into the database.
+  #
+  # The generated ID for a given label is constant, so we can discover
+  # any fixture's ID without loading anything, as long as we know the label.
+  #
+  # == Label references for associations (belongs_to, has_one, has_many)
+  #
+  # Specifying foreign keys in fixtures can be very fragile, not to
+  # mention difficult to read. Since Active Record can figure out the ID of
+  # any fixture from its label, you can specify FK's by label instead of ID.
+  #
+  # === belongs_to
+  #
+  # Let's break out some more monkeys and pirates.
+  #
+  #   ### in pirates.yml
+  #
+  #   reginald:
+  #     id: 1
+  #     name: Reginald the Pirate
+  #     monkey_id: 1
+  #
+  #   ### in monkeys.yml
+  #
+  #   george:
+  #     id: 1
+  #     name: George the Monkey
+  #     pirate_id: 1
+  #
+  # Add a few more monkeys and pirates and break this into multiple files,
+  # and it gets pretty hard to keep track of what's going on. Let's
+  # use labels instead of IDs:
+  #
+  #   ### in pirates.yml
+  #
+  #   reginald:
+  #     name: Reginald the Pirate
+  #     monkey: george
+  #
+  #   ### in monkeys.yml
+  #
+  #   george:
+  #     name: George the Monkey
+  #     pirate: reginald
+  #
+  # Pow! All is made clear. Active Record reflects on the fixture's model class,
+  # finds all the +belongs_to+ associations, and allows you to specify
+  # a target *label* for the *association* (monkey: george) rather than
+  # a target *id* for the *FK* (<tt>monkey_id: 1</tt>).
+  #
+  # ==== Polymorphic belongs_to
+  #
+  # Supporting polymorphic relationships is a little bit more complicated, since
+  # Active Record needs to know what type your association is pointing at. Something
+  # like this should look familiar:
+  #
+  #   ### in fruit.rb
+  #
+  #   belongs_to :eater, polymorphic: true
+  #
+  #   ### in fruits.yml
+  #
+  #   apple:
+  #     id: 1
+  #     name: apple
+  #     eater_id: 1
+  #     eater_type: Monkey
+  #
+  # Can we do better? You bet!
+  #
+  #   apple:
+  #     eater: george (Monkey)
+  #
+  # Just provide the polymorphic target type and Active Record will take care of the rest.
+  #
+  # === has_and_belongs_to_many
+  #
+  # Time to give our monkey some fruit.
+  #
+  #   ### in monkeys.yml
+  #
+  #   george:
+  #     id: 1
+  #     name: George the Monkey
+  #
+  #   ### in fruits.yml
+  #
+  #   apple:
+  #     id: 1
+  #     name: apple
+  #
+  #   orange:
+  #     id: 2
+  #     name: orange
+  #
+  #   grape:
+  #     id: 3
+  #     name: grape
+  #
+  #   ### in fruits_monkeys.yml
+  #
+  #   apple_george:
+  #     fruit_id: 1
+  #     monkey_id: 1
+  #
+  #   orange_george:
+  #     fruit_id: 2
+  #     monkey_id: 1
+  #
+  #   grape_george:
+  #     fruit_id: 3
+  #     monkey_id: 1
+  #
+  # Let's make the HABTM fixture go away.
+  #
+  #   ### in monkeys.yml
+  #
+  #   george:
+  #     id: 1
+  #     name: George the Monkey
+  #     fruits: apple, orange, grape
+  #
+  #   ### in fruits.yml
+  #
+  #   apple:
+  #     name: apple
+  #
+  #   orange:
+  #     name: orange
+  #
+  #   grape:
+  #     name: grape
+  #
+  # Zap! No more fruits_monkeys.yml file. We've specified the list of fruits
+  # on George's fixture, but we could've just as easily specified a list
+  # of monkeys on each fruit. As with +belongs_to+, Active Record reflects on
+  # the fixture's model class and discovers the +has_and_belongs_to_many+
+  # associations.
+  #
+  # == Autofilled Timestamp Columns
+  #
+  # If your table/model specifies any of Active Record's
+  # standard timestamp columns (+created_at+, +created_on+, +updated_at+, +updated_on+),
+  # they will automatically be set to <tt>Time.now</tt>.
+  #
+  # If you've set specific values, they'll be left alone.
+  #
+  # == Fixture label interpolation
+  #
+  # The label of the current fixture is always available as a column value:
+  #
+  #   geeksomnia:
+  #     name: Geeksomnia's Account
+  #     subdomain: $LABEL
+  #     email: $LABEL@email.com
+  #
+  # Also, sometimes (like when porting older join table fixtures) you'll need
+  # to be able to get a hold of the identifier for a given label. ERB
+  # to the rescue:
+  #
+  #   george_reginald:
+  #     monkey_id: <%= ActiveRecord::FixtureSet.identify(:reginald) %>
+  #     pirate_id: <%= ActiveRecord::FixtureSet.identify(:george) %>
+  #
+  # == Support for YAML defaults
+  #
+  # You can set and reuse defaults in your fixtures YAML file.
+  # This is the same technique used in the +database.yml+ file to specify
+  # defaults:
+  #
+  #   DEFAULTS: &DEFAULTS
+  #     created_on: <%= 3.weeks.ago.to_s(:db) %>
+  #
+  #   first:
+  #     name: Smurf
+  #     <<: *DEFAULTS
+  #
+  #   second:
+  #     name: Fraggle
+  #     <<: *DEFAULTS
+  #
+  # Any fixture labeled "DEFAULTS" is safely ignored.
+  class FixtureSet
+    #--
+    # An instance of FixtureSet is normally stored in a single YAML file and
+    # possibly in a folder with the same name.
+    #++
+
+    MAX_ID = 2 ** 30 - 1
+
+    @@all_cached_fixtures = Hash.new { |h,k| h[k] = {} }
+
+    def self.default_fixture_model_name(fixture_set_name, config = ActiveRecord::Base) # :nodoc:
+      config.pluralize_table_names ?
+        fixture_set_name.singularize.camelize :
+        fixture_set_name.camelize
+    end
+
+    def self.default_fixture_table_name(fixture_set_name, config = ActiveRecord::Base) # :nodoc:
+       "#{ config.table_name_prefix }"\
+       "#{ fixture_set_name.tr('/', '_') }"\
+       "#{ config.table_name_suffix }".to_sym
+    end
+
+    def self.reset_cache
+      @@all_cached_fixtures.clear
+    end
+
+    def self.cache_for_connection(connection)
+      @@all_cached_fixtures[connection]
+    end
+
+    def self.fixture_is_cached?(connection, table_name)
+      cache_for_connection(connection)[table_name]
+    end
+
+    def self.cached_fixtures(connection, keys_to_fetch = nil)
+      if keys_to_fetch
+        cache_for_connection(connection).values_at(*keys_to_fetch)
+      else
+        cache_for_connection(connection).values
+      end
+    end
+
+    def self.cache_fixtures(connection, fixtures_map)
+      cache_for_connection(connection).update(fixtures_map)
+    end
+
+    def self.instantiate_fixtures(object, fixture_set, load_instances = true)
+      if load_instances
+        fixture_set.each do |fixture_name, fixture|
+          begin
+            object.instance_variable_set "@#{fixture_name}", fixture.find
+          rescue FixtureClassNotFound
+            nil
+          end
+        end
+      end
+    end
+
+    def self.instantiate_all_loaded_fixtures(object, load_instances = true)
+      all_loaded_fixtures.each_value do |fixture_set|
+        instantiate_fixtures(object, fixture_set, load_instances)
+      end
+    end
+
+    cattr_accessor :all_loaded_fixtures
+    self.all_loaded_fixtures = {}
+
+    class ClassCache
+      def initialize(class_names, config)
+        @class_names = class_names.stringify_keys
+        @config      = config
+
+        # Remove string values that aren't constants or subclasses of AR
+        @class_names.delete_if { |klass_name, klass| !insert_class(@class_names, klass_name, klass) }
+      end
+
+      def [](fs_name)
+        @class_names.fetch(fs_name) {
+          klass = default_fixture_model(fs_name, @config).safe_constantize
+          insert_class(@class_names, fs_name, klass)
+        }
+      end
+
+      private
+
+      def insert_class(class_names, name, klass)
+        # We only want to deal with AR objects.
+        if klass && klass < ActiveRecord::Base
+          class_names[name] = klass
+        else
+          class_names[name] = nil
+        end
+      end
+
+      def default_fixture_model(fs_name, config)
+        ActiveRecord::FixtureSet.default_fixture_model_name(fs_name, config)
+      end
+    end
+
+    def self.create_fixtures(fixtures_directory, fixture_set_names, class_names = {}, config = ActiveRecord::Base)
+      fixture_set_names = Array(fixture_set_names).map(&:to_s)
+      class_names = ClassCache.new class_names, config
+
+      # FIXME: Apparently JK uses this.
+      connection = block_given? ? yield : ActiveRecord::Base.connection
+
+      files_to_read = fixture_set_names.reject { |fs_name|
+        fixture_is_cached?(connection, fs_name)
+      }
+
+      unless files_to_read.empty?
+        connection.disable_referential_integrity do
+          fixtures_map = {}
+
+          fixture_sets = files_to_read.map do |fs_name|
+            klass = class_names[fs_name]
+            conn = klass ? klass.connection : connection
+            fixtures_map[fs_name] = new( # ActiveRecord::FixtureSet.new
+              conn,
+              fs_name,
+              klass,
+              ::File.join(fixtures_directory, fs_name))
+          end
+
+          all_loaded_fixtures.update(fixtures_map)
+
+          connection.transaction(:requires_new => true) do
+            fixture_sets.each do |fs|
+              conn = fs.model_class.respond_to?(:connection) ? fs.model_class.connection : connection
+              table_rows = fs.table_rows
+
+              table_rows.keys.each do |table|
+                conn.delete "DELETE FROM #{conn.quote_table_name(table)}", 'Fixture Delete'
+              end
+
+              table_rows.each do |fixture_set_name, rows|
+                rows.each do |row|
+                  conn.insert_fixture(row, fixture_set_name)
+                end
+              end
+            end
+
+            # Cap primary key sequences to max(pk).
+            if connection.respond_to?(:reset_pk_sequence!)
+              fixture_sets.each do |fs|
+                connection.reset_pk_sequence!(fs.table_name)
+              end
+            end
+          end
+
+          cache_fixtures(connection, fixtures_map)
+        end
+      end
+      cached_fixtures(connection, fixture_set_names)
+    end
+
+    # Returns a consistent, platform-independent identifier for +label+.
+    # Integer identifiers are values less than 2^30. UUIDs are RFC 4122 version 5 SHA-1 hashes.
+    def self.identify(label, column_type = :integer)
+      if column_type == :uuid
+        Digest::UUID.uuid_v5(Digest::UUID::OID_NAMESPACE, label.to_s)
+      else
+        Zlib.crc32(label.to_s) % MAX_ID
+      end
+    end
+
+    # Superclass for the evaluation contexts used by ERB fixtures.
+    def self.context_class
+      @context_class ||= Class.new
+    end
+
+    attr_reader :table_name, :name, :fixtures, :model_class, :config
+
+    def initialize(connection, name, class_name, path, config = ActiveRecord::Base)
+      @name     = name
+      @path     = path
+      @config   = config
+      @model_class = nil
+
+      if class_name.is_a?(Class) # TODO: Should be an AR::Base type class, or any?
+        @model_class = class_name
+      else
+        @model_class = class_name.safe_constantize if class_name
+      end
+
+      @connection  = connection
+
+      @table_name = ( model_class.respond_to?(:table_name) ?
+                      model_class.table_name :
+                      self.class.default_fixture_table_name(name, config) )
+
+      @fixtures = read_fixture_files path, @model_class
+    end
+
+    def [](x)
+      fixtures[x]
+    end
+
+    def []=(k,v)
+      fixtures[k] = v
+    end
+
+    def each(&block)
+      fixtures.each(&block)
+    end
+
+    def size
+      fixtures.size
+    end
+
+    # Returns a hash of rows to be inserted. The key is the table, the value is
+    # a list of rows to insert to that table.
+    def table_rows
+      now = config.default_timezone == :utc ? Time.now.utc : Time.now
+      now = now.to_s(:db)
+
+      # allow a standard key to be used for doing defaults in YAML
+      fixtures.delete('DEFAULTS')
+
+      # track any join tables we need to insert later
+      rows = Hash.new { |h,table| h[table] = [] }
+
+      rows[table_name] = fixtures.map do |label, fixture|
+        row = fixture.to_hash
+
+        if model_class
+          # fill in timestamp columns if they aren't specified and the model is set to record_timestamps
+          if model_class.record_timestamps
+            timestamp_column_names.each do |c_name|
+              row[c_name] = now unless row.key?(c_name)
+            end
+          end
+
+          # interpolate the fixture label
+          row.each do |key, value|
+            row[key] = value.gsub("$LABEL", label) if value.is_a?(String)
+          end
+
+          # generate a primary key if necessary
+          if has_primary_key_column? && !row.include?(primary_key_name)
+            row[primary_key_name] = ActiveRecord::FixtureSet.identify(label, primary_key_type)
+          end
+
+          # If STI is used, find the correct subclass for association reflection
+          reflection_class =
+            if row.include?(inheritance_column_name)
+              row[inheritance_column_name].constantize rescue model_class
+            else
+              model_class
+            end
+
+          reflection_class._reflections.values.each do |association|
+            case association.macro
+            when :belongs_to
+              # Do not replace association name with association foreign key if they are named the same
+              fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s
+
+              if association.name.to_s != fk_name && value = row.delete(association.name.to_s)
+                if association.polymorphic? && value.sub!(/\s*\(([^\)]*)\)\s*$/, "")
+                  # support polymorphic belongs_to as "label (Type)"
+                  row[association.foreign_type] = $1
+                end
+
+                fk_type = association.active_record.columns_hash[association.foreign_key].type
+                row[fk_name] = ActiveRecord::FixtureSet.identify(value, fk_type)
+              end
+            when :has_many
+              if association.options[:through]
+                add_join_records(rows, row, HasManyThroughProxy.new(association))
+              end
+            end
+          end
+        end
+
+        row
+      end
+      rows
+    end
+
+    class ReflectionProxy # :nodoc:
+      def initialize(association)
+        @association = association
+      end
+
+      def join_table
+        @association.join_table
+      end
+
+      def name
+        @association.name
+      end
+
+      def primary_key_type
+        @association.klass.column_types[@association.klass.primary_key].type
+      end
+    end
+
+    class HasManyThroughProxy < ReflectionProxy # :nodoc:
+      def rhs_key
+        @association.foreign_key
+      end
+
+      def lhs_key
+        @association.through_reflection.foreign_key
+      end
+    end
+
+    private
+      def primary_key_name
+        @primary_key_name ||= model_class && model_class.primary_key
+      end
+
+      def primary_key_type
+        @primary_key_type ||= model_class && model_class.column_types[model_class.primary_key].type
+      end
+
+      def add_join_records(rows, row, association)
+        # This is the case when the join table has no fixtures file
+        if (targets = row.delete(association.name.to_s))
+          table_name  = association.join_table
+          column_type = association.primary_key_type
+          lhs_key     = association.lhs_key
+          rhs_key     = association.rhs_key
+
+          targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
+          rows[table_name].concat targets.map { |target|
+            { lhs_key => row[primary_key_name],
+              rhs_key => ActiveRecord::FixtureSet.identify(target, column_type) }
+          }
+        end
+      end
+
+      def has_primary_key_column?
+        @has_primary_key_column ||= primary_key_name &&
+          model_class.columns.any? { |c| c.name == primary_key_name }
+      end
+
+      def timestamp_column_names
+        @timestamp_column_names ||=
+          %w(created_at created_on updated_at updated_on) & column_names
+      end
+
+      def inheritance_column_name
+        @inheritance_column_name ||= model_class && model_class.inheritance_column
+      end
+
+      def column_names
+        @column_names ||= @connection.columns(@table_name).collect { |c| c.name }
+      end
+
+      def read_fixture_files(path, model_class)
+        yaml_files = Dir["#{path}/{**,*}/*.yml"].select { |f|
+          ::File.file?(f)
+        } + [yaml_file_path(path)]
+
+        yaml_files.each_with_object({}) do |file, fixtures|
+          FixtureSet::File.open(file) do |fh|
+            fh.each do |fixture_name, row|
+              fixtures[fixture_name] = ActiveRecord::Fixture.new(row, model_class)
+            end
+          end
+        end
+      end
+
+      def yaml_file_path(path)
+        "#{path}.yml"
+      end
+
+  end
+
+  #--
+  # Deprecate 'Fixtures' in favor of 'FixtureSet'.
+  #++
+  # :nodoc:
+  Fixtures = ActiveSupport::Deprecation::DeprecatedConstantProxy.new('ActiveRecord::Fixtures', 'ActiveRecord::FixtureSet')
+
+  class Fixture #:nodoc:
+    include Enumerable
+
+    class FixtureError < StandardError #:nodoc:
+    end
+
+    class FormatError < FixtureError #:nodoc:
+    end
+
+    attr_reader :model_class, :fixture
+
+    def initialize(fixture, model_class)
+      @fixture     = fixture
+      @model_class = model_class
+    end
+
+    def class_name
+      model_class.name if model_class
+    end
+
+    def each
+      fixture.each { |item| yield item }
+    end
+
+    def [](key)
+      fixture[key]
+    end
+
+    alias :to_hash :fixture
+
+    def find
+      if model_class
+        model_class.find(fixture[model_class.primary_key])
+      else
+        raise FixtureClassNotFound, "No class attached to find."
+      end
+    end
+  end
+end
+
+module ActiveRecord
+  module TestFixtures
+    extend ActiveSupport::Concern
+
+    def before_setup
+      setup_fixtures
+      super
+    end
+
+    def after_teardown
+      super
+      teardown_fixtures
+    end
+
+    included do
+      class_attribute :fixture_path, :instance_writer => false
+      class_attribute :fixture_table_names
+      class_attribute :fixture_class_names
+      class_attribute :use_transactional_fixtures
+      class_attribute :use_instantiated_fixtures # true, false, or :no_instances
+      class_attribute :pre_loaded_fixtures
+      class_attribute :config
+
+      self.fixture_table_names = []
+      self.use_transactional_fixtures = true
+      self.use_instantiated_fixtures = false
+      self.pre_loaded_fixtures = false
+      self.config = ActiveRecord::Base
+
+      self.fixture_class_names = Hash.new do |h, fixture_set_name|
+        h[fixture_set_name] = ActiveRecord::FixtureSet.default_fixture_model_name(fixture_set_name, self.config)
+      end
+    end
+
+    module ClassMethods
+      # Sets the model class for a fixture when the class name cannot be inferred from the fixture name.
+      #
+      # Examples:
+      #
+      #   set_fixture_class some_fixture:        SomeModel,
+      #                     'namespaced/fixture' => Another::Model
+      #
+      # The keys must be the fixture names, that coincide with the short paths to the fixture files.
+      def set_fixture_class(class_names = {})
+        self.fixture_class_names = self.fixture_class_names.merge(class_names.stringify_keys)
+      end
+
+      def fixtures(*fixture_set_names)
+        if fixture_set_names.first == :all
+          fixture_set_names = Dir["#{fixture_path}/{**,*}/*.{yml}"]
+          fixture_set_names.map! { |f| f[(fixture_path.to_s.size + 1)..-5] }
+        else
+          fixture_set_names = fixture_set_names.flatten.map { |n| n.to_s }
+        end
+
+        self.fixture_table_names |= fixture_set_names
+        require_fixture_classes(fixture_set_names, self.config)
+        setup_fixture_accessors(fixture_set_names)
+      end
+
+      def try_to_load_dependency(file_name)
+        require_dependency file_name
+      rescue LoadError => e
+        # Let's hope the developer has included it
+        # Let's warn in case this is a subdependency, otherwise
+        # subdependency error messages are totally cryptic
+        if ActiveRecord::Base.logger
+          ActiveRecord::Base.logger.warn("Unable to load #{file_name}, underlying cause #{e.message} \n\n #{e.backtrace.join("\n")}")
+        end
+      end
+
+      def require_fixture_classes(fixture_set_names = nil, config = ActiveRecord::Base)
+        if fixture_set_names
+          fixture_set_names = fixture_set_names.map { |n| n.to_s }
+        else
+          fixture_set_names = fixture_table_names
+        end
+
+        fixture_set_names.each do |file_name|
+          file_name = file_name.singularize if config.pluralize_table_names
+          try_to_load_dependency(file_name)
+        end
+      end
+
+      def setup_fixture_accessors(fixture_set_names = nil)
+        fixture_set_names = Array(fixture_set_names || fixture_table_names)
+        methods = Module.new do
+          fixture_set_names.each do |fs_name|
+            fs_name = fs_name.to_s
+            accessor_name = fs_name.tr('/', '_').to_sym
+
+            define_method(accessor_name) do |*fixture_names|
+              force_reload = fixture_names.pop if fixture_names.last == true || fixture_names.last == :reload
+
+              @fixture_cache[fs_name] ||= {}
+
+              instances = fixture_names.map do |f_name|
+                f_name = f_name.to_s
+                @fixture_cache[fs_name].delete(f_name) if force_reload
+
+                if @loaded_fixtures[fs_name][f_name]
+                  @fixture_cache[fs_name][f_name] ||= @loaded_fixtures[fs_name][f_name].find
+                else
+                  raise StandardError, "No fixture named '#{f_name}' found for fixture set '#{fs_name}'"
+                end
+              end
+
+              instances.size == 1 ? instances.first : instances
+            end
+            private accessor_name
+          end
+        end
+        include methods
+      end
+
+      def uses_transaction(*methods)
+        @uses_transaction = [] unless defined?(@uses_transaction)
+        @uses_transaction.concat methods.map { |m| m.to_s }
+      end
+
+      def uses_transaction?(method)
+        @uses_transaction = [] unless defined?(@uses_transaction)
+        @uses_transaction.include?(method.to_s)
+      end
+    end
+
+    def run_in_transaction?
+      use_transactional_fixtures &&
+        !self.class.uses_transaction?(method_name)
+    end
+
+    def setup_fixtures(config = ActiveRecord::Base)
+      if pre_loaded_fixtures && !use_transactional_fixtures
+        raise RuntimeError, 'pre_loaded_fixtures requires use_transactional_fixtures'
+      end
+
+      @fixture_cache = {}
+      @fixture_connections = []
+      @@already_loaded_fixtures ||= {}
+
+      # Load fixtures once and begin transaction.
+      if run_in_transaction?
+        if @@already_loaded_fixtures[self.class]
+          @loaded_fixtures = @@already_loaded_fixtures[self.class]
+        else
+          @loaded_fixtures = load_fixtures(config)
+          @@already_loaded_fixtures[self.class] = @loaded_fixtures
+        end
+        @fixture_connections = enlist_fixture_connections
+        @fixture_connections.each do |connection|
+          connection.begin_transaction joinable: false
+        end
+      # Load fixtures for every test.
+      else
+        ActiveRecord::FixtureSet.reset_cache
+        @@already_loaded_fixtures[self.class] = nil
+        @loaded_fixtures = load_fixtures(config)
+      end
+
+      # Instantiate fixtures for every test if requested.
+      instantiate_fixtures(config) if use_instantiated_fixtures
+    end
+
+    def teardown_fixtures
+      # Rollback changes if a transaction is active.
+      if run_in_transaction?
+        @fixture_connections.each do |connection|
+          connection.rollback_transaction if connection.transaction_open?
+        end
+        @fixture_connections.clear
+      else
+        ActiveRecord::FixtureSet.reset_cache
+      end
+
+      ActiveRecord::Base.clear_active_connections!
+    end
+
+    def enlist_fixture_connections
+      ActiveRecord::Base.connection_handler.connection_pool_list.map(&:connection)
+    end
+
+    private
+      def load_fixtures(config)
+        fixtures = ActiveRecord::FixtureSet.create_fixtures(fixture_path, fixture_table_names, fixture_class_names, config)
+        Hash[fixtures.map { |f| [f.name, f] }]
+      end
+
+      # for pre_loaded_fixtures, only require the classes once. huge speed improvement
+      @@required_fixture_classes = false
+
+      def instantiate_fixtures(config)
+        if pre_loaded_fixtures
+          raise RuntimeError, 'Load fixtures before instantiating them.' if ActiveRecord::FixtureSet.all_loaded_fixtures.empty?
+          unless @@required_fixture_classes
+            self.class.require_fixture_classes ActiveRecord::FixtureSet.all_loaded_fixtures.keys, config
+            @@required_fixture_classes = true
+          end
+          ActiveRecord::FixtureSet.instantiate_all_loaded_fixtures(self, load_instances?)
+        else
+          raise RuntimeError, 'Load fixtures before instantiating them.' if @loaded_fixtures.nil?
+          @loaded_fixtures.each_value do |fixture_set|
+            ActiveRecord::FixtureSet.instantiate_fixtures(self, fixture_set, load_instances?)
+          end
+        end
+      end
+
+      def load_instances?
+        use_instantiated_fixtures != :no_instances
+      end
+  end
+end
+
+class ActiveRecord::FixtureSet::RenderContext # :nodoc:
+  def self.create_subclass
+    Class.new ActiveRecord::FixtureSet.context_class do
+      def get_binding
+        binding()
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/gem_version.rb b/activerecord/lib/active_record/gem_version.rb
new file mode 100644
index 0000000000..4a7aace460
--- /dev/null
+++ b/activerecord/lib/active_record/gem_version.rb
@@ -0,0 +1,15 @@
+module ActiveRecord
+  # Returns the version of the currently loaded ActiveRecord as a <tt>Gem::Version</tt>
+  def self.gem_version
+    Gem::Version.new VERSION::STRING
+  end
+
+  module VERSION
+    MAJOR = 4
+    MINOR = 2
+    TINY  = 0
+    PRE   = "alpha"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
+  end
+end
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
new file mode 100644
index 0000000000..251d682a02
--- /dev/null
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -0,0 +1,247 @@
+require 'active_support/core_ext/hash/indifferent_access'
+
+module ActiveRecord
+  # == Single table inheritance
+  #
+  # Active Record allows inheritance by storing the name of the class in a column that by
+  # default is named "type" (can be changed by overwriting <tt>Base.inheritance_column</tt>).
+  # This means that an inheritance looking like this:
+  #
+  #   class Company < ActiveRecord::Base; end
+  #   class Firm < Company; end
+  #   class Client < Company; end
+  #   class PriorityClient < Client; end
+  #
+  # When you do <tt>Firm.create(name: "37signals")</tt>, this record will be saved in
+  # the companies table with type = "Firm". You can then fetch this row again using
+  # <tt>Company.where(name: '37signals').first</tt> and it will return a Firm object.
+  #
+  # Be aware that because the type column is an attribute on the record every new
+  # subclass will instantly be marked as dirty and the type column will be included
+  # in the list of changed attributes on the record. This is different from non
+  # STI classes:
+  #
+  #   Company.new.changed? # => false
+  #   Firm.new.changed?    # => true
+  #   Firm.new.changes     # => {"type"=>["","Firm"]}
+  #
+  # If you don't have a type column defined in your table, single-table inheritance won't
+  # be triggered. In that case, it'll work just like normal subclasses with no special magic
+  # for differentiating between them or reloading the right type with find.
+  #
+  # Note, all the attributes for all the cases are kept in the same table. Read more:
+  # http://www.martinfowler.com/eaaCatalog/singleTableInheritance.html
+  #
+  module Inheritance
+    extend ActiveSupport::Concern
+
+    included do
+      # Determines whether to store the full constant name including namespace when using STI.
+      class_attribute :store_full_sti_class, instance_writer: false
+      self.store_full_sti_class = true
+    end
+
+    module ClassMethods
+      # Determines if one of the attributes passed in is the inheritance column,
+      # and if the inheritance column is attr accessible, it initializes an
+      # instance of the given subclass instead of the base class.
+      def new(*args, &block)
+        if abstract_class? || self == Base
+          raise NotImplementedError, "#{self} is an abstract class and cannot be instantiated."
+        end
+
+        attrs = args.first
+        if subclass_from_attributes?(attrs)
+          subclass = subclass_from_attributes(attrs)
+        end
+
+        if subclass
+          subclass.new(*args, &block)
+        else
+          super
+        end
+      end
+
+      # Returns +true+ if this does not need STI type condition. Returns
+      # +false+ if STI type condition needs to be applied.
+      def descends_from_active_record?
+        if self == Base
+          false
+        elsif superclass.abstract_class?
+          superclass.descends_from_active_record?
+        else
+          superclass == Base || !columns_hash.include?(inheritance_column)
+        end
+      end
+
+      def finder_needs_type_condition? #:nodoc:
+        # This is like this because benchmarking justifies the strange :false stuff
+        :true == (@finder_needs_type_condition ||= descends_from_active_record? ? :false : :true)
+      end
+
+      def symbolized_base_class
+        ActiveSupport::Deprecation.warn("ActiveRecord::Base.symbolized_base_class is deprecated and will be removed without replacement.")
+        @symbolized_base_class ||= base_class.to_s.to_sym
+      end
+
+      def symbolized_sti_name
+        ActiveSupport::Deprecation.warn("ActiveRecord::Base.symbolized_sti_name is deprecated and will be removed without replacement.")
+        @symbolized_sti_name ||= sti_name.present? ? sti_name.to_sym : symbolized_base_class
+      end
+
+      # Returns the class descending directly from ActiveRecord::Base, or
+      # an abstract class, if any, in the inheritance hierarchy.
+      #
+      # If A extends AR::Base, A.base_class will return A. If B descends from A
+      # through some arbitrarily deep hierarchy, B.base_class will return A.
+      #
+      # If B < A and C < B and if A is an abstract_class then both B.base_class
+      # and C.base_class would return B as the answer since A is an abstract_class.
+      def base_class
+        unless self < Base
+          raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
+        end
+
+        if superclass == Base || superclass.abstract_class?
+          self
+        else
+          superclass.base_class
+        end
+      end
+
+      # Set this to true if this is an abstract class (see <tt>abstract_class?</tt>).
+      # If you are using inheritance with ActiveRecord and don't want child classes
+      # to utilize the implied STI table name of the parent class, this will need to be true.
+      # For example, given the following:
+      #
+      #   class SuperClass < ActiveRecord::Base
+      #     self.abstract_class = true
+      #   end
+      #   class Child < SuperClass
+      #     self.table_name = 'the_table_i_really_want'
+      #   end
+      #
+      #
+      # <tt>self.abstract_class = true</tt> is required to make <tt>Child<.find,.create, or any Arel method></tt> use <tt>the_table_i_really_want</tt> instead of a table called <tt>super_classes</tt>
+      #
+      attr_accessor :abstract_class
+
+      # Returns whether this class is an abstract class or not.
+      def abstract_class?
+        defined?(@abstract_class) && @abstract_class == true
+      end
+
+      def sti_name
+        store_full_sti_class ? name : name.demodulize
+      end
+
+      protected
+
+      # Returns the class type of the record using the current module as a prefix. So descendants of
+      # MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.
+      def compute_type(type_name)
+        if type_name.match(/^::/)
+          # If the type is prefixed with a scope operator then we assume that
+          # the type_name is an absolute reference.
+          ActiveSupport::Dependencies.constantize(type_name)
+        else
+          # Build a list of candidates to search for
+          candidates = []
+          name.scan(/::|$/) { candidates.unshift "#{$`}::#{type_name}" }
+          candidates << type_name
+
+          candidates.each do |candidate|
+            constant = ActiveSupport::Dependencies.safe_constantize(candidate)
+            return constant if candidate == constant.to_s
+          end
+
+          raise NameError.new("uninitialized constant #{candidates.first}", candidates.first)
+        end
+      end
+
+      private
+
+      # Called by +instantiate+ to decide which class to use for a new
+      # record instance. For single-table inheritance, we check the record
+      # for a +type+ column and return the corresponding class.
+      def discriminate_class_for_record(record)
+        if using_single_table_inheritance?(record)
+          find_sti_class(record[inheritance_column])
+        else
+          super
+        end
+      end
+
+      def using_single_table_inheritance?(record)
+        record[inheritance_column].present? && columns_hash.include?(inheritance_column)
+      end
+
+      def find_sti_class(type_name)
+        if store_full_sti_class
+          ActiveSupport::Dependencies.constantize(type_name)
+        else
+          compute_type(type_name)
+        end
+      rescue NameError
+        raise SubclassNotFound,
+          "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " +
+          "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
+          "Please rename this column if you didn't intend it to be used for storing the inheritance class " +
+          "or overwrite #{name}.inheritance_column to use another column for that information."
+      end
+
+      def type_condition(table = arel_table)
+        sti_column = table[inheritance_column]
+        sti_names  = ([self] + descendants).map { |model| model.sti_name }
+
+        sti_column.in(sti_names)
+      end
+
+      # Detect the subclass from the inheritance column of attrs. If the inheritance column value
+      # is not self or a valid subclass, raises ActiveRecord::SubclassNotFound
+      # If this is a StrongParameters hash, and access to inheritance_column is not permitted,
+      # this will ignore the inheritance column and return nil
+      def subclass_from_attributes?(attrs)
+        columns_hash.include?(inheritance_column) && attrs.is_a?(Hash)
+      end
+
+      def subclass_from_attributes(attrs)
+        subclass_name = attrs.with_indifferent_access[inheritance_column]
+
+        if subclass_name.present? && subclass_name != self.name
+          subclass = subclass_name.safe_constantize
+
+          unless descendants.include?(subclass)
+            raise ActiveRecord::SubclassNotFound.new("Invalid single-table inheritance type: #{subclass_name} is not a subclass of #{name}")
+          end
+
+          subclass
+        end
+      end
+    end
+
+    def initialize_dup(other)
+      super
+      ensure_proper_type
+    end
+
+    private
+
+    def initialize_internals_callback
+      super
+      ensure_proper_type
+    end
+
+    # Sets the attribute used for single table inheritance to this class name if this is not the
+    # ActiveRecord::Base descendant.
+    # Considering the hierarchy Reply < Message < ActiveRecord::Base, this makes it possible to
+    # do Reply.new without having to set <tt>Reply[Reply.inheritance_column] = "Reply"</tt> yourself.
+    # No such attribute would be set for objects of the Message class in that example.
+    def ensure_proper_type
+      klass = self.class
+      if klass.finder_needs_type_condition?
+        write_attribute(klass.inheritance_column, klass.sti_name)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
new file mode 100644
index 0000000000..31e2518540
--- /dev/null
+++ b/activerecord/lib/active_record/integration.rb
@@ -0,0 +1,113 @@
+require 'active_support/core_ext/string/filters'
+
+module ActiveRecord
+  module Integration
+    extend ActiveSupport::Concern
+
+    included do
+      ##
+      # :singleton-method:
+      # Indicates the format used to generate the timestamp in the cache key.
+      # Accepts any of the symbols in <tt>Time::DATE_FORMATS</tt>.
+      #
+      # This is +:nsec+, by default.
+      class_attribute :cache_timestamp_format, :instance_writer => false
+      self.cache_timestamp_format = :nsec
+    end
+
+    # Returns a String, which Action Pack uses for constructing an URL to this
+    # object. The default implementation returns this record's id as a String,
+    # or nil if this record's unsaved.
+    #
+    # For example, suppose that you have a User model, and that you have a
+    # <tt>resources :users</tt> route. Normally, +user_path+ will
+    # construct a path with the user object's 'id' in it:
+    #
+    #   user = User.find_by(name: 'Phusion')
+    #   user_path(user)  # => "/users/1"
+    #
+    # You can override +to_param+ in your model to make +user_path+ construct
+    # a path using the user's name instead of the user's id:
+    #
+    #   class User < ActiveRecord::Base
+    #     def to_param  # overridden
+    #       name
+    #     end
+    #   end
+    #
+    #   user = User.find_by(name: 'Phusion')
+    #   user_path(user)  # => "/users/Phusion"
+    def to_param
+      # We can't use alias_method here, because method 'id' optimizes itself on the fly.
+      id && id.to_s # Be sure to stringify the id for routes
+    end
+
+    # Returns a cache key that can be used to identify this record.
+    #
+    #   Product.new.cache_key     # => "products/new"
+    #   Product.find(5).cache_key # => "products/5" (updated_at not available)
+    #   Person.find(5).cache_key  # => "people/5-20071224150000" (updated_at available)
+    #
+    # You can also pass a list of named timestamps, and the newest in the list will be
+    # used to generate the key:
+    #
+    #   Person.find(5).cache_key(:updated_at, :last_reviewed_at)
+    def cache_key(*timestamp_names)
+      case
+      when new_record?
+        "#{self.class.model_name.cache_key}/new"
+      when timestamp_names.any?
+        timestamp = max_updated_column_timestamp(timestamp_names)
+        timestamp = timestamp.utc.to_s(cache_timestamp_format)
+        "#{self.class.model_name.cache_key}/#{id}-#{timestamp}"
+      when timestamp = max_updated_column_timestamp
+        timestamp = timestamp.utc.to_s(cache_timestamp_format)
+        "#{self.class.model_name.cache_key}/#{id}-#{timestamp}"
+      else
+        "#{self.class.model_name.cache_key}/#{id}"
+      end
+    end
+
+    module ClassMethods
+      # Defines your model's +to_param+ method to generate "pretty" URLs
+      # using +method_name+, which can be any attribute or method that
+      # responds to +to_s+.
+      #
+      #   class User < ActiveRecord::Base
+      #     to_param :name
+      #   end
+      #
+      #   user = User.find_by(name: 'Fancy Pants')
+      #   user.id         # => 123
+      #   user_path(user) # => "/users/123-fancy-pants"
+      #
+      # Values longer than 20 characters will be truncated. The value
+      # is truncated word by word.
+      #
+      #   user = User.find_by(name: 'David HeinemeierHansson')
+      #   user.id         # => 125
+      #   user_path(user) # => "/users/125-david"
+      #
+      # Because the generated param begins with the record's +id+, it is
+      # suitable for passing to +find+. In a controller, for example:
+      #
+      #   params[:id]               # => "123-fancy-pants"
+      #   User.find(params[:id]).id # => 123
+      def to_param(method_name = nil)
+        if method_name.nil?
+          super()
+        else
+          define_method :to_param do
+            if (default = super()) &&
+                 (result = send(method_name).to_s).present? &&
+                   (param = result.squish.truncate(20, separator: /\s/, omission: nil).parameterize).present?
+              "#{default}-#{param}"
+            else
+              default
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/locale/en.yml b/activerecord/lib/active_record/locale/en.yml
new file mode 100644
index 0000000000..b1fbd38622
--- /dev/null
+++ b/activerecord/lib/active_record/locale/en.yml
@@ -0,0 +1,47 @@
+en:
+  # Attributes names common to most models
+  #attributes:
+    #created_at: "Created at"
+    #updated_at: "Updated at"
+
+  # Default error messages
+  errors:
+    messages:
+      taken: "has already been taken"
+
+  # Active Record models configuration
+  activerecord:
+    errors:
+      messages:
+        record_invalid: "Validation failed: %{errors}"
+        restrict_dependent_destroy:
+          one: "Cannot delete record because a dependent %{record} exists"
+          many: "Cannot delete record because dependent %{record} exist"
+        # Append your own errors here or at the model/attributes scope.
+
+      # You can define own errors for models or model attributes.
+      # The values :model, :attribute and :value are always available for interpolation.
+      #
+      # For example,
+      #   models:
+      #     user:
+      #       blank: "This is a custom blank message for %{model}: %{attribute}"
+      #       attributes:
+      #         login:
+      #           blank: "This is a custom blank message for User login"
+      # Will define custom blank validation message for User model and
+      # custom blank validation message for login attribute of User model.
+      #models:
+
+    # Translate model names. Used in Model.human_name().
+    #models:
+      # For example,
+      #   user: "Dude"
+      # will translate User model name to "Dude"
+
+    # Translate model attribute names. Used in Model.human_attribute_name(attribute).
+    #attributes:
+      # For example,
+      #   user:
+      #     login: "Handle"
+      # will translate User attribute "login" as "Handle"
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
new file mode 100644
index 0000000000..52eeb8ae1f
--- /dev/null
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -0,0 +1,204 @@
+module ActiveRecord
+  module Locking
+    # == What is Optimistic Locking
+    #
+    # Optimistic locking allows multiple users to access the same record for edits, and assumes a minimum of
+    # conflicts with the data. It does this by checking whether another process has made changes to a record since
+    # it was opened, an <tt>ActiveRecord::StaleObjectError</tt> exception is thrown if that has occurred
+    # and the update is ignored.
+    #
+    # Check out <tt>ActiveRecord::Locking::Pessimistic</tt> for an alternative.
+    #
+    # == Usage
+    #
+    # Active Records support optimistic locking if the field +lock_version+ is present. Each update to the
+    # record increments the +lock_version+ column and the locking facilities ensure that records instantiated twice
+    # will let the last one saved raise a +StaleObjectError+ if the first was also updated. Example:
+    #
+    #   p1 = Person.find(1)
+    #   p2 = Person.find(1)
+    #
+    #   p1.first_name = "Michael"
+    #   p1.save
+    #
+    #   p2.first_name = "should fail"
+    #   p2.save # Raises a ActiveRecord::StaleObjectError
+    #
+    # Optimistic locking will also check for stale data when objects are destroyed. Example:
+    #
+    #   p1 = Person.find(1)
+    #   p2 = Person.find(1)
+    #
+    #   p1.first_name = "Michael"
+    #   p1.save
+    #
+    #   p2.destroy # Raises a ActiveRecord::StaleObjectError
+    #
+    # You're then responsible for dealing with the conflict by rescuing the exception and either rolling back, merging,
+    # or otherwise apply the business logic needed to resolve the conflict.
+    #
+    # This locking mechanism will function inside a single Ruby process. To make it work across all
+    # web requests, the recommended approach is to add +lock_version+ as a hidden field to your form.
+    #
+    # This behavior can be turned off by setting <tt>ActiveRecord::Base.lock_optimistically = false</tt>.
+    # To override the name of the +lock_version+ column, set the <tt>locking_column</tt> class attribute:
+    #
+    #   class Person < ActiveRecord::Base
+    #     self.locking_column = :lock_person
+    #   end
+    #
+    module Optimistic
+      extend ActiveSupport::Concern
+
+      included do
+        class_attribute :lock_optimistically, instance_writer: false
+        self.lock_optimistically = true
+      end
+
+      def locking_enabled? #:nodoc:
+        self.class.locking_enabled?
+      end
+
+      private
+        def increment_lock
+          lock_col = self.class.locking_column
+          previous_lock_value = send(lock_col).to_i
+          send(lock_col + '=', previous_lock_value + 1)
+        end
+
+        def _update_record(attribute_names = self.attribute_names) #:nodoc:
+          return super unless locking_enabled?
+          return 0 if attribute_names.empty?
+
+          lock_col = self.class.locking_column
+          previous_lock_value = send(lock_col).to_i
+          increment_lock
+
+          attribute_names += [lock_col]
+          attribute_names.uniq!
+
+          begin
+            relation = self.class.unscoped
+
+            stmt = relation.where(
+              relation.table[self.class.primary_key].eq(id).and(
+                relation.table[lock_col].eq(self.class.quote_value(previous_lock_value, column_for_attribute(lock_col)))
+              )
+            ).arel.compile_update(
+              arel_attributes_with_values_for_update(attribute_names),
+              self.class.primary_key
+            )
+
+            affected_rows = self.class.connection.update stmt
+
+            unless affected_rows == 1
+              raise ActiveRecord::StaleObjectError.new(self, "update")
+            end
+
+            affected_rows
+
+          # If something went wrong, revert the version.
+          rescue Exception
+            send(lock_col + '=', previous_lock_value)
+            raise
+          end
+        end
+
+        def destroy_row
+          affected_rows = super
+
+          if locking_enabled? && affected_rows != 1
+            raise ActiveRecord::StaleObjectError.new(self, "destroy")
+          end
+
+          affected_rows
+        end
+
+        def relation_for_destroy
+          relation = super
+
+          if locking_enabled?
+            column_name = self.class.locking_column
+            column      = self.class.columns_hash[column_name]
+            substitute  = self.class.connection.substitute_at(column, relation.bind_values.length)
+
+            relation = relation.where(self.class.arel_table[column_name].eq(substitute))
+            relation.bind_values << [column, self[column_name].to_i]
+          end
+
+          relation
+        end
+
+      module ClassMethods
+        DEFAULT_LOCKING_COLUMN = 'lock_version'
+
+        # Returns true if the +lock_optimistically+ flag is set to true
+        # (which it is, by default) and the table includes the
+        # +locking_column+ column (defaults to +lock_version+).
+        def locking_enabled?
+          lock_optimistically && columns_hash[locking_column]
+        end
+
+        # Set the column to use for optimistic locking. Defaults to +lock_version+.
+        def locking_column=(value)
+          clear_caches_calculated_from_columns
+          @locking_column = value.to_s
+        end
+
+        # The version column used for optimistic locking. Defaults to +lock_version+.
+        def locking_column
+          reset_locking_column unless defined?(@locking_column)
+          @locking_column
+        end
+
+        # Reset the column used for optimistic locking back to the +lock_version+ default.
+        def reset_locking_column
+          self.locking_column = DEFAULT_LOCKING_COLUMN
+        end
+
+        # Make sure the lock version column gets updated when counters are
+        # updated.
+        def update_counters(id, counters)
+          counters = counters.merge(locking_column => 1) if locking_enabled?
+          super
+        end
+
+        private
+
+        # We need to apply this decorator here, rather than on module inclusion. The closure
+        # created by the matcher would otherwise evaluate for `ActiveRecord::Base`, not the
+        # sub class being decorated. As such, changes to `lock_optimistically`, or
+        # `locking_column` would not be picked up.
+        def inherited(subclass)
+          subclass.class_eval do
+            is_lock_column = ->(name, _) { lock_optimistically && name == locking_column }
+            decorate_matching_attribute_types(is_lock_column, :_optimistic_locking) do |type|
+              LockingType.new(type)
+            end
+          end
+          super
+        end
+      end
+    end
+
+    class LockingType < SimpleDelegator # :nodoc:
+      def type_cast_from_database(value)
+        # `nil` *should* be changed to 0
+        super.to_i
+      end
+
+      def changed?(old_value, *)
+        # Ensure we save if the default was `nil`
+        super || old_value == 0
+      end
+
+      def init_with(coder)
+        __setobj__(coder['subtype'])
+      end
+
+      def encode_with(coder)
+        coder['subtype'] = __getobj__
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/locking/pessimistic.rb b/activerecord/lib/active_record/locking/pessimistic.rb
new file mode 100644
index 0000000000..ff7102d35b
--- /dev/null
+++ b/activerecord/lib/active_record/locking/pessimistic.rb
@@ -0,0 +1,77 @@
+module ActiveRecord
+  module Locking
+    # Locking::Pessimistic provides support for row-level locking using
+    # SELECT ... FOR UPDATE and other lock types.
+    #
+    # Chain <tt>ActiveRecord::Base#find</tt> to <tt>ActiveRecord::QueryMethods#lock</tt> to obtain an exclusive
+    # lock on the selected rows:
+    #   # select * from accounts where id=1 for update
+    #   Account.lock.find(1)
+    #
+    # Call <tt>lock('some locking clause')</tt> to use a database-specific locking clause
+    # of your own such as 'LOCK IN SHARE MODE' or 'FOR UPDATE NOWAIT'. Example:
+    #
+    #   Account.transaction do
+    #     # select * from accounts where name = 'shugo' limit 1 for update
+    #     shugo = Account.where("name = 'shugo'").lock(true).first
+    #     yuko = Account.where("name = 'yuko'").lock(true).first
+    #     shugo.balance -= 100
+    #     shugo.save!
+    #     yuko.balance += 100
+    #     yuko.save!
+    #   end
+    #
+    # You can also use <tt>ActiveRecord::Base#lock!</tt> method to lock one record by id.
+    # This may be better if you don't need to lock every row. Example:
+    #
+    #   Account.transaction do
+    #     # select * from accounts where ...
+    #     accounts = Account.where(...)
+    #     account1 = accounts.detect { |account| ... }
+    #     account2 = accounts.detect { |account| ... }
+    #     # select * from accounts where id=? for update
+    #     account1.lock!
+    #     account2.lock!
+    #     account1.balance -= 100
+    #     account1.save!
+    #     account2.balance += 100
+    #     account2.save!
+    #   end
+    #
+    # You can start a transaction and acquire the lock in one go by calling
+    # <tt>with_lock</tt> with a block. The block is called from within
+    # a transaction, the object is already locked. Example:
+    #
+    #   account = Account.first
+    #   account.with_lock do
+    #     # This block is called within a transaction,
+    #     # account is already locked.
+    #     account.balance -= 100
+    #     account.save!
+    #   end
+    #
+    # Database-specific information on row locking:
+    #   MySQL: http://dev.mysql.com/doc/refman/5.1/en/innodb-locking-reads.html
+    #   PostgreSQL: http://www.postgresql.org/docs/current/interactive/sql-select.html#SQL-FOR-UPDATE-SHARE
+    module Pessimistic
+      # Obtain a row lock on this record. Reloads the record to obtain the requested
+      # lock. Pass an SQL locking clause to append the end of the SELECT statement
+      # or pass true for "FOR UPDATE" (the default, an exclusive row lock). Returns
+      # the locked record.
+      def lock!(lock = true)
+        reload(:lock => lock) if persisted?
+        self
+      end
+
+      # Wraps the passed block in a transaction, locking the object
+      # before yielding. You can pass the SQL locking clause
+      # as argument (see <tt>lock!</tt>).
+      def with_lock(lock = true)
+        transaction do
+          lock!(lock)
+          yield
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/log_subscriber.rb b/activerecord/lib/active_record/log_subscriber.rb
new file mode 100644
index 0000000000..eb64d197f0
--- /dev/null
+++ b/activerecord/lib/active_record/log_subscriber.rb
@@ -0,0 +1,75 @@
+module ActiveRecord
+  class LogSubscriber < ActiveSupport::LogSubscriber
+    IGNORE_PAYLOAD_NAMES = ["SCHEMA", "EXPLAIN"]
+
+    def self.runtime=(value)
+      ActiveRecord::RuntimeRegistry.sql_runtime = value
+    end
+
+    def self.runtime
+      ActiveRecord::RuntimeRegistry.sql_runtime ||= 0
+    end
+
+    def self.reset_runtime
+      rt, self.runtime = runtime, 0
+      rt
+    end
+
+    def initialize
+      super
+      @odd = false
+    end
+
+    def render_bind(column, value)
+      if column
+        if column.binary?
+          # This specifically deals with the PG adapter that casts bytea columns into a Hash.
+          value = value[:value] if value.is_a?(Hash)
+          value = value ? "<#{value.bytesize} bytes of binary data>" : "<NULL binary data>"
+        end
+
+        [column.name, value]
+      else
+        [nil, value]
+      end
+    end
+
+    def sql(event)
+      self.class.runtime += event.duration
+      return unless logger.debug?
+
+      payload = event.payload
+
+      return if IGNORE_PAYLOAD_NAMES.include?(payload[:name])
+
+      name  = "#{payload[:name]} (#{event.duration.round(1)}ms)"
+      sql   = payload[:sql]
+      binds = nil
+
+      unless (payload[:binds] || []).empty?
+        binds = "  " + payload[:binds].map { |col,v|
+          render_bind(col, v)
+        }.inspect
+      end
+
+      if odd?
+        name = color(name, CYAN, true)
+        sql  = color(sql, nil, true)
+      else
+        name = color(name, MAGENTA, true)
+      end
+
+      debug "  #{name}  #{sql}#{binds}"
+    end
+
+    def odd?
+      @odd = !@odd
+    end
+
+    def logger
+      ActiveRecord::Base.logger
+    end
+  end
+end
+
+ActiveRecord::LogSubscriber.attach_to :active_record
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
new file mode 100644
index 0000000000..a6847e28c2
--- /dev/null
+++ b/activerecord/lib/active_record/migration.rb
@@ -0,0 +1,1045 @@
+require "active_support/core_ext/module/attribute_accessors"
+require 'set'
+
+module ActiveRecord
+  class MigrationError < ActiveRecordError#:nodoc:
+    def initialize(message = nil)
+      message = "\n\n#{message}\n\n" if message
+      super
+    end
+  end
+
+  # Exception that can be raised to stop migrations from going backwards.
+  class IrreversibleMigration < MigrationError
+  end
+
+  class DuplicateMigrationVersionError < MigrationError#:nodoc:
+    def initialize(version)
+      super("Multiple migrations have the version number #{version}")
+    end
+  end
+
+  class DuplicateMigrationNameError < MigrationError#:nodoc:
+    def initialize(name)
+      super("Multiple migrations have the name #{name}")
+    end
+  end
+
+  class UnknownMigrationVersionError < MigrationError #:nodoc:
+    def initialize(version)
+      super("No migration with version number #{version}")
+    end
+  end
+
+  class IllegalMigrationNameError < MigrationError#:nodoc:
+    def initialize(name)
+      super("Illegal name for migration file: #{name}\n\t(only lower case letters, numbers, and '_' allowed)")
+    end
+  end
+
+  class PendingMigrationError < MigrationError#:nodoc:
+    def initialize
+      if defined?(Rails)
+        super("Migrations are pending. To resolve this issue, run:\n\n\tbin/rake db:migrate RAILS_ENV=#{::Rails.env}")
+      else
+        super("Migrations are pending. To resolve this issue, run:\n\n\tbin/rake db:migrate")
+      end
+    end
+  end
+
+  # = Active Record Migrations
+  #
+  # Migrations can manage the evolution of a schema used by several physical
+  # databases. It's a solution to the common problem of adding a field to make
+  # a new feature work in your local database, but being unsure of how to
+  # push that change to other developers and to the production server. With
+  # migrations, you can describe the transformations in self-contained classes
+  # that can be checked into version control systems and executed against
+  # another database that might be one, two, or five versions behind.
+  #
+  # Example of a simple migration:
+  #
+  #   class AddSsl < ActiveRecord::Migration
+  #     def up
+  #       add_column :accounts, :ssl_enabled, :boolean, default: true
+  #     end
+  #
+  #     def down
+  #       remove_column :accounts, :ssl_enabled
+  #     end
+  #   end
+  #
+  # This migration will add a boolean flag to the accounts table and remove it
+  # if you're backing out of the migration. It shows how all migrations have
+  # two methods +up+ and +down+ that describes the transformations
+  # required to implement or remove the migration. These methods can consist
+  # of both the migration specific methods like +add_column+ and +remove_column+,
+  # but may also contain regular Ruby code for generating data needed for the
+  # transformations.
+  #
+  # Example of a more complex migration that also needs to initialize data:
+  #
+  #   class AddSystemSettings < ActiveRecord::Migration
+  #     def up
+  #       create_table :system_settings do |t|
+  #         t.string  :name
+  #         t.string  :label
+  #         t.text    :value
+  #         t.string  :type
+  #         t.integer :position
+  #       end
+  #
+  #       SystemSetting.create  name:  'notice',
+  #                             label: 'Use notice?',
+  #                             value: 1
+  #     end
+  #
+  #     def down
+  #       drop_table :system_settings
+  #     end
+  #   end
+  #
+  # This migration first adds the +system_settings+ table, then creates the very
+  # first row in it using the Active Record model that relies on the table. It
+  # also uses the more advanced +create_table+ syntax where you can specify a
+  # complete table schema in one block call.
+  #
+  # == Available transformations
+  #
+  # * <tt>create_table(name, options)</tt>: Creates a table called +name+ and
+  #   makes the table object available to a block that can then add columns to it,
+  #   following the same format as +add_column+. See example above. The options hash
+  #   is for fragments like "DEFAULT CHARSET=UTF-8" that are appended to the create
+  #   table definition.
+  # * <tt>drop_table(name)</tt>: Drops the table called +name+.
+  # * <tt>change_table(name, options)</tt>: Allows to make column alterations to
+  #   the table called +name+. It makes the table object available to a block that
+  #   can then add/remove columns, indexes or foreign keys to it.
+  # * <tt>rename_table(old_name, new_name)</tt>: Renames the table called +old_name+
+  #   to +new_name+.
+  # * <tt>add_column(table_name, column_name, type, options)</tt>: Adds a new column
+  #   to the table called +table_name+
+  #   named +column_name+ specified to be one of the following types:
+  #   <tt>:string</tt>, <tt>:text</tt>, <tt>:integer</tt>, <tt>:float</tt>,
+  #   <tt>:decimal</tt>, <tt>:datetime</tt>, <tt>:timestamp</tt>, <tt>:time</tt>,
+  #   <tt>:date</tt>, <tt>:binary</tt>, <tt>:boolean</tt>. A default value can be
+  #   specified by passing an +options+ hash like <tt>{ default: 11 }</tt>.
+  #   Other options include <tt>:limit</tt> and <tt>:null</tt> (e.g.
+  #   <tt>{ limit: 50, null: false }</tt>) -- see
+  #   ActiveRecord::ConnectionAdapters::TableDefinition#column for details.
+  # * <tt>rename_column(table_name, column_name, new_column_name)</tt>: Renames
+  #   a column but keeps the type and content.
+  # * <tt>change_column(table_name, column_name, type, options)</tt>:  Changes
+  #   the column to a different type using the same parameters as add_column.
+  # * <tt>remove_column(table_name, column_name, type, options)</tt>: Removes the column
+  #   named +column_name+ from the table called +table_name+.
+  # * <tt>add_index(table_name, column_names, options)</tt>: Adds a new index
+  #   with the name of the column. Other options include
+  #   <tt>:name</tt>, <tt>:unique</tt> (e.g.
+  #   <tt>{ name: 'users_name_index', unique: true }</tt>) and <tt>:order</tt>
+  #   (e.g. <tt>{ order: { name: :desc } }</tt>).
+  # * <tt>remove_index(table_name, column: column_name)</tt>: Removes the index
+  #   specified by +column_name+.
+  # * <tt>remove_index(table_name, name: index_name)</tt>: Removes the index
+  #   specified by +index_name+.
+  #
+  # == Irreversible transformations
+  #
+  # Some transformations are destructive in a manner that cannot be reversed.
+  # Migrations of that kind should raise an <tt>ActiveRecord::IrreversibleMigration</tt>
+  # exception in their +down+ method.
+  #
+  # == Running migrations from within Rails
+  #
+  # The Rails package has several tools to help create and apply migrations.
+  #
+  # To generate a new migration, you can use
+  #   rails generate migration MyNewMigration
+  #
+  # where MyNewMigration is the name of your migration. The generator will
+  # create an empty migration file <tt>timestamp_my_new_migration.rb</tt>
+  # in the <tt>db/migrate/</tt> directory where <tt>timestamp</tt> is the
+  # UTC formatted date and time that the migration was generated.
+  #
+  # You may then edit the <tt>up</tt> and <tt>down</tt> methods of
+  # MyNewMigration.
+  #
+  # There is a special syntactic shortcut to generate migrations that add fields to a table.
+  #
+  #   rails generate migration add_fieldname_to_tablename fieldname:string
+  #
+  # This will generate the file <tt>timestamp_add_fieldname_to_tablename</tt>, which will look like this:
+  #   class AddFieldnameToTablename < ActiveRecord::Migration
+  #     def up
+  #       add_column :tablenames, :fieldname, :string
+  #     end
+  #
+  #     def down
+  #       remove_column :tablenames, :fieldname
+  #     end
+  #   end
+  #
+  # To run migrations against the currently configured database, use
+  # <tt>rake db:migrate</tt>. This will update the database by running all of the
+  # pending migrations, creating the <tt>schema_migrations</tt> table
+  # (see "About the schema_migrations table" section below) if missing. It will also
+  # invoke the db:schema:dump task, which will update your db/schema.rb file
+  # to match the structure of your database.
+  #
+  # To roll the database back to a previous migration version, use
+  # <tt>rake db:migrate VERSION=X</tt> where <tt>X</tt> is the version to which
+  # you wish to downgrade. If any of the migrations throw an
+  # <tt>ActiveRecord::IrreversibleMigration</tt> exception, that step will fail and you'll
+  # have some manual work to do.
+  #
+  # == Database support
+  #
+  # Migrations are currently supported in MySQL, PostgreSQL, SQLite,
+  # SQL Server, and Oracle (all supported databases except DB2).
+  #
+  # == More examples
+  #
+  # Not all migrations change the schema. Some just fix the data:
+  #
+  #   class RemoveEmptyTags < ActiveRecord::Migration
+  #     def up
+  #       Tag.all.each { |tag| tag.destroy if tag.pages.empty? }
+  #     end
+  #
+  #     def down
+  #       # not much we can do to restore deleted data
+  #       raise ActiveRecord::IrreversibleMigration, "Can't recover the deleted tags"
+  #     end
+  #   end
+  #
+  # Others remove columns when they migrate up instead of down:
+  #
+  #   class RemoveUnnecessaryItemAttributes < ActiveRecord::Migration
+  #     def up
+  #       remove_column :items, :incomplete_items_count
+  #       remove_column :items, :completed_items_count
+  #     end
+  #
+  #     def down
+  #       add_column :items, :incomplete_items_count
+  #       add_column :items, :completed_items_count
+  #     end
+  #   end
+  #
+  # And sometimes you need to do something in SQL not abstracted directly by migrations:
+  #
+  #   class MakeJoinUnique < ActiveRecord::Migration
+  #     def up
+  #       execute "ALTER TABLE `pages_linked_pages` ADD UNIQUE `page_id_linked_page_id` (`page_id`,`linked_page_id`)"
+  #     end
+  #
+  #     def down
+  #       execute "ALTER TABLE `pages_linked_pages` DROP INDEX `page_id_linked_page_id`"
+  #     end
+  #   end
+  #
+  # == Using a model after changing its table
+  #
+  # Sometimes you'll want to add a column in a migration and populate it
+  # immediately after. In that case, you'll need to make a call to
+  # <tt>Base#reset_column_information</tt> in order to ensure that the model has the
+  # latest column data from after the new column was added. Example:
+  #
+  #   class AddPeopleSalary < ActiveRecord::Migration
+  #     def up
+  #       add_column :people, :salary, :integer
+  #       Person.reset_column_information
+  #       Person.all.each do |p|
+  #         p.update_attribute :salary, SalaryCalculator.compute(p)
+  #       end
+  #     end
+  #   end
+  #
+  # == Controlling verbosity
+  #
+  # By default, migrations will describe the actions they are taking, writing
+  # them to the console as they happen, along with benchmarks describing how
+  # long each step took.
+  #
+  # You can quiet them down by setting ActiveRecord::Migration.verbose = false.
+  #
+  # You can also insert your own messages and benchmarks by using the +say_with_time+
+  # method:
+  #
+  #   def up
+  #     ...
+  #     say_with_time "Updating salaries..." do
+  #       Person.all.each do |p|
+  #         p.update_attribute :salary, SalaryCalculator.compute(p)
+  #       end
+  #     end
+  #     ...
+  #   end
+  #
+  # The phrase "Updating salaries..." would then be printed, along with the
+  # benchmark for the block when the block completes.
+  #
+  # == About the schema_migrations table
+  #
+  # Rails versions 2.0 and prior used to create a table called
+  # <tt>schema_info</tt> when using migrations. This table contained the
+  # version of the schema as of the last applied migration.
+  #
+  # Starting with Rails 2.1, the <tt>schema_info</tt> table is
+  # (automatically) replaced by the <tt>schema_migrations</tt> table, which
+  # contains the version numbers of all the migrations applied.
+  #
+  # As a result, it is now possible to add migration files that are numbered
+  # lower than the current schema version: when migrating up, those
+  # never-applied "interleaved" migrations will be automatically applied, and
+  # when migrating down, never-applied "interleaved" migrations will be skipped.
+  #
+  # == Timestamped Migrations
+  #
+  # By default, Rails generates migrations that look like:
+  #
+  #    20080717013526_your_migration_name.rb
+  #
+  # The prefix is a generation timestamp (in UTC).
+  #
+  # If you'd prefer to use numeric prefixes, you can turn timestamped migrations
+  # off by setting:
+  #
+  #    config.active_record.timestamped_migrations = false
+  #
+  # In application.rb.
+  #
+  # == Reversible Migrations
+  #
+  # Starting with Rails 3.1, you will be able to define reversible migrations.
+  # Reversible migrations are migrations that know how to go +down+ for you.
+  # You simply supply the +up+ logic, and the Migration system will figure out
+  # how to execute the down commands for you.
+  #
+  # To define a reversible migration, define the +change+ method in your
+  # migration like this:
+  #
+  #   class TenderloveMigration < ActiveRecord::Migration
+  #     def change
+  #       create_table(:horses) do |t|
+  #         t.column :content, :text
+  #         t.column :remind_at, :datetime
+  #       end
+  #     end
+  #   end
+  #
+  # This migration will create the horses table for you on the way up, and
+  # automatically figure out how to drop the table on the way down.
+  #
+  # Some commands like +remove_column+ cannot be reversed.  If you care to
+  # define how to move up and down in these cases, you should define the +up+
+  # and +down+ methods as before.
+  #
+  # If a command cannot be reversed, an
+  # <tt>ActiveRecord::IrreversibleMigration</tt> exception will be raised when
+  # the migration is moving down.
+  #
+  # For a list of commands that are reversible, please see
+  # <tt>ActiveRecord::Migration::CommandRecorder</tt>.
+  #
+  # == Transactional Migrations
+  #
+  # If the database adapter supports DDL transactions, all migrations will
+  # automatically be wrapped in a transaction. There are queries that you
+  # can't execute inside a transaction though, and for these situations
+  # you can turn the automatic transactions off.
+  #
+  #   class ChangeEnum < ActiveRecord::Migration
+  #     disable_ddl_transaction!
+  #
+  #     def up
+  #       execute "ALTER TYPE model_size ADD VALUE 'new_value'"
+  #     end
+  #   end
+  #
+  # Remember that you can still open your own transactions, even if you
+  # are in a Migration with <tt>self.disable_ddl_transaction!</tt>.
+  class Migration
+    autoload :CommandRecorder, 'active_record/migration/command_recorder'
+
+
+    # This class is used to verify that all migrations have been run before
+    # loading a web page if config.active_record.migration_error is set to :page_load
+    class CheckPending
+      def initialize(app)
+        @app = app
+        @last_check = 0
+      end
+
+      def call(env)
+        if connection.supports_migrations?
+          mtime = ActiveRecord::Migrator.last_migration.mtime.to_i
+          if @last_check < mtime
+            ActiveRecord::Migration.check_pending!(connection)
+            @last_check = mtime
+          end
+        end
+        @app.call(env)
+      end
+
+      private
+
+      def connection
+        ActiveRecord::Base.connection
+      end
+    end
+
+    class << self
+      attr_accessor :delegate # :nodoc:
+      attr_accessor :disable_ddl_transaction # :nodoc:
+
+      def check_pending!(connection = Base.connection)
+        raise ActiveRecord::PendingMigrationError if ActiveRecord::Migrator.needs_migration?(connection)
+      end
+
+      def load_schema_if_pending!
+        if ActiveRecord::Migrator.needs_migration?
+          ActiveRecord::Tasks::DatabaseTasks.load_schema_current
+          check_pending!
+        end
+      end
+
+      def maintain_test_schema! # :nodoc:
+        if ActiveRecord::Base.maintain_test_schema
+          suppress_messages { load_schema_if_pending! }
+        end
+      end
+
+      def method_missing(name, *args, &block) # :nodoc:
+        (delegate || superclass.delegate).send(name, *args, &block)
+      end
+
+      def migrate(direction)
+        new.migrate direction
+      end
+
+      # Disable DDL transactions for this migration.
+      def disable_ddl_transaction!
+        @disable_ddl_transaction = true
+      end
+    end
+
+    def disable_ddl_transaction # :nodoc:
+      self.class.disable_ddl_transaction
+    end
+
+    cattr_accessor :verbose
+    attr_accessor :name, :version
+
+    def initialize(name = self.class.name, version = nil)
+      @name       = name
+      @version    = version
+      @connection = nil
+    end
+
+    self.verbose = true
+    # instantiate the delegate object after initialize is defined
+    self.delegate = new
+
+    # Reverses the migration commands for the given block and
+    # the given migrations.
+    #
+    # The following migration will remove the table 'horses'
+    # and create the table 'apples' on the way up, and the reverse
+    # on the way down.
+    #
+    #   class FixTLMigration < ActiveRecord::Migration
+    #     def change
+    #       revert do
+    #         create_table(:horses) do |t|
+    #           t.text :content
+    #           t.datetime :remind_at
+    #         end
+    #       end
+    #       create_table(:apples) do |t|
+    #         t.string :variety
+    #       end
+    #     end
+    #   end
+    #
+    # Or equivalently, if +TenderloveMigration+ is defined as in the
+    # documentation for Migration:
+    #
+    #   require_relative '2012121212_tenderlove_migration'
+    #
+    #   class FixupTLMigration < ActiveRecord::Migration
+    #     def change
+    #       revert TenderloveMigration
+    #
+    #       create_table(:apples) do |t|
+    #         t.string :variety
+    #       end
+    #     end
+    #   end
+    #
+    # This command can be nested.
+    def revert(*migration_classes)
+      run(*migration_classes.reverse, revert: true) unless migration_classes.empty?
+      if block_given?
+        if @connection.respond_to? :revert
+          @connection.revert { yield }
+        else
+          recorder = CommandRecorder.new(@connection)
+          @connection = recorder
+          suppress_messages do
+            @connection.revert { yield }
+          end
+          @connection = recorder.delegate
+          recorder.commands.each do |cmd, args, block|
+            send(cmd, *args, &block)
+          end
+        end
+      end
+    end
+
+    def reverting?
+      @connection.respond_to?(:reverting) && @connection.reverting
+    end
+
+    class ReversibleBlockHelper < Struct.new(:reverting) # :nodoc:
+      def up
+        yield unless reverting
+      end
+
+      def down
+        yield if reverting
+      end
+    end
+
+    # Used to specify an operation that can be run in one direction or another.
+    # Call the methods +up+ and +down+ of the yielded object to run a block
+    # only in one given direction.
+    # The whole block will be called in the right order within the migration.
+    #
+    # In the following example, the looping on users will always be done
+    # when the three columns 'first_name', 'last_name' and 'full_name' exist,
+    # even when migrating down:
+    #
+    #    class SplitNameMigration < ActiveRecord::Migration
+    #      def change
+    #        add_column :users, :first_name, :string
+    #        add_column :users, :last_name, :string
+    #
+    #        reversible do |dir|
+    #          User.reset_column_information
+    #          User.all.each do |u|
+    #            dir.up   { u.first_name, u.last_name = u.full_name.split(' ') }
+    #            dir.down { u.full_name = "#{u.first_name} #{u.last_name}" }
+    #            u.save
+    #          end
+    #        end
+    #
+    #        revert { add_column :users, :full_name, :string }
+    #      end
+    #    end
+    def reversible
+      helper = ReversibleBlockHelper.new(reverting?)
+      execute_block{ yield helper }
+    end
+
+    # Runs the given migration classes.
+    # Last argument can specify options:
+    # - :direction (default is :up)
+    # - :revert (default is false)
+    def run(*migration_classes)
+      opts = migration_classes.extract_options!
+      dir = opts[:direction] || :up
+      dir = (dir == :down ? :up : :down) if opts[:revert]
+      if reverting?
+        # If in revert and going :up, say, we want to execute :down without reverting, so
+        revert { run(*migration_classes, direction: dir, revert: true) }
+      else
+        migration_classes.each do |migration_class|
+          migration_class.new.exec_migration(@connection, dir)
+        end
+      end
+    end
+
+    def up
+      self.class.delegate = self
+      return unless self.class.respond_to?(:up)
+      self.class.up
+    end
+
+    def down
+      self.class.delegate = self
+      return unless self.class.respond_to?(:down)
+      self.class.down
+    end
+
+    # Execute this migration in the named direction
+    def migrate(direction)
+      return unless respond_to?(direction)
+
+      case direction
+      when :up   then announce "migrating"
+      when :down then announce "reverting"
+      end
+
+      time   = nil
+      ActiveRecord::Base.connection_pool.with_connection do |conn|
+        time = Benchmark.measure do
+          exec_migration(conn, direction)
+        end
+      end
+
+      case direction
+      when :up   then announce "migrated (%.4fs)" % time.real; write
+      when :down then announce "reverted (%.4fs)" % time.real; write
+      end
+    end
+
+    def exec_migration(conn, direction)
+      @connection = conn
+      if respond_to?(:change)
+        if direction == :down
+          revert { change }
+        else
+          change
+        end
+      else
+        send(direction)
+      end
+    ensure
+      @connection = nil
+    end
+
+    def write(text="")
+      puts(text) if verbose
+    end
+
+    def announce(message)
+      text = "#{version} #{name}: #{message}"
+      length = [0, 75 - text.length].max
+      write "== %s %s" % [text, "=" * length]
+    end
+
+    def say(message, subitem=false)
+      write "#{subitem ? "   ->" : "--"} #{message}"
+    end
+
+    def say_with_time(message)
+      say(message)
+      result = nil
+      time = Benchmark.measure { result = yield }
+      say "%.4fs" % time.real, :subitem
+      say("#{result} rows", :subitem) if result.is_a?(Integer)
+      result
+    end
+
+    def suppress_messages
+      save, self.verbose = verbose, false
+      yield
+    ensure
+      self.verbose = save
+    end
+
+    def connection
+      @connection || ActiveRecord::Base.connection
+    end
+
+    def method_missing(method, *arguments, &block)
+      arg_list = arguments.map{ |a| a.inspect } * ', '
+
+      say_with_time "#{method}(#{arg_list})" do
+        unless @connection.respond_to? :revert
+          unless arguments.empty? || [:execute, :enable_extension, :disable_extension].include?(method)
+            arguments[0] = proper_table_name(arguments.first, table_name_options)
+            if [:rename_table, :add_foreign_key].include?(method)
+              arguments[1] = proper_table_name(arguments.second, table_name_options)
+            end
+          end
+        end
+        return super unless connection.respond_to?(method)
+        connection.send(method, *arguments, &block)
+      end
+    end
+
+    def copy(destination, sources, options = {})
+      copied = []
+
+      FileUtils.mkdir_p(destination) unless File.exist?(destination)
+
+      destination_migrations = ActiveRecord::Migrator.migrations(destination)
+      last = destination_migrations.last
+      sources.each do |scope, path|
+        source_migrations = ActiveRecord::Migrator.migrations(path)
+
+        source_migrations.each do |migration|
+          source = File.binread(migration.filename)
+          inserted_comment = "# This migration comes from #{scope} (originally #{migration.version})\n"
+          if /\A#.*\b(?:en)?coding:\s*\S+/ =~ source
+            # If we have a magic comment in the original migration,
+            # insert our comment after the first newline(end of the magic comment line)
+            # so the magic keep working.
+            # Note that magic comments must be at the first line(except sh-bang).
+            source[/\n/] = "\n#{inserted_comment}"
+          else
+            source = "#{inserted_comment}#{source}"
+          end
+
+          if duplicate = destination_migrations.detect { |m| m.name == migration.name }
+            if options[:on_skip] && duplicate.scope != scope.to_s
+              options[:on_skip].call(scope, migration)
+            end
+            next
+          end
+
+          migration.version = next_migration_number(last ? last.version + 1 : 0).to_i
+          new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.#{scope}.rb")
+          old_path, migration.filename = migration.filename, new_path
+          last = migration
+
+          File.binwrite(migration.filename, source)
+          copied << migration
+          options[:on_copy].call(scope, migration, old_path) if options[:on_copy]
+          destination_migrations << migration
+        end
+      end
+
+      copied
+    end
+
+    # Finds the correct table name given an Active Record object.
+    # Uses the Active Record object's own table_name, or pre/suffix from the
+    # options passed in.
+    def proper_table_name(name, options = {})
+      if name.respond_to? :table_name
+        name.table_name
+      else
+        "#{options[:table_name_prefix]}#{name}#{options[:table_name_suffix]}"
+      end
+    end
+
+    # Determines the version number of the next migration.
+    def next_migration_number(number)
+      if ActiveRecord::Base.timestamped_migrations
+        [Time.now.utc.strftime("%Y%m%d%H%M%S"), "%.14d" % number].max
+      else
+        SchemaMigration.normalize_migration_number(number)
+      end
+    end
+
+    def table_name_options(config = ActiveRecord::Base)
+      {
+        table_name_prefix: config.table_name_prefix,
+        table_name_suffix: config.table_name_suffix
+      }
+    end
+
+    private
+    def execute_block
+      if connection.respond_to? :execute_block
+        super # use normal delegation to record the block
+      else
+        yield
+      end
+    end
+  end
+
+  # MigrationProxy is used to defer loading of the actual migration classes
+  # until they are needed
+  class MigrationProxy < Struct.new(:name, :version, :filename, :scope)
+
+    def initialize(name, version, filename, scope)
+      super
+      @migration = nil
+    end
+
+    def basename
+      File.basename(filename)
+    end
+
+    def mtime
+      File.mtime filename
+    end
+
+    delegate :migrate, :announce, :write, :disable_ddl_transaction, to: :migration
+
+    private
+
+      def migration
+        @migration ||= load_migration
+      end
+
+      def load_migration
+        require(File.expand_path(filename))
+        name.constantize.new(name, version)
+      end
+
+  end
+
+  class NullMigration < MigrationProxy #:nodoc:
+    def initialize
+      super(nil, 0, nil, nil)
+    end
+
+    def mtime
+      0
+    end
+  end
+
+  class Migrator#:nodoc:
+    class << self
+      attr_writer :migrations_paths
+      alias :migrations_path= :migrations_paths=
+
+      def migrate(migrations_paths, target_version = nil, &block)
+        case
+        when target_version.nil?
+          up(migrations_paths, target_version, &block)
+        when current_version == 0 && target_version == 0
+          []
+        when current_version > target_version
+          down(migrations_paths, target_version, &block)
+        else
+          up(migrations_paths, target_version, &block)
+        end
+      end
+
+      def rollback(migrations_paths, steps=1)
+        move(:down, migrations_paths, steps)
+      end
+
+      def forward(migrations_paths, steps=1)
+        move(:up, migrations_paths, steps)
+      end
+
+      def up(migrations_paths, target_version = nil)
+        migrations = migrations(migrations_paths)
+        migrations.select! { |m| yield m } if block_given?
+
+        new(:up, migrations, target_version).migrate
+      end
+
+      def down(migrations_paths, target_version = nil, &block)
+        migrations = migrations(migrations_paths)
+        migrations.select! { |m| yield m } if block_given?
+
+        new(:down, migrations, target_version).migrate
+      end
+
+      def run(direction, migrations_paths, target_version)
+        new(direction, migrations(migrations_paths), target_version).run
+      end
+
+      def open(migrations_paths)
+        new(:up, migrations(migrations_paths), nil)
+      end
+
+      def schema_migrations_table_name
+        SchemaMigration.table_name
+      end
+
+      def get_all_versions
+        SchemaMigration.all.map { |x| x.version.to_i }.sort
+      end
+
+      def current_version(connection = Base.connection)
+        sm_table = schema_migrations_table_name
+        if connection.table_exists?(sm_table)
+          get_all_versions.max || 0
+        else
+          0
+        end
+      end
+
+      def needs_migration?(connection = Base.connection)
+        current_version(connection) < last_version
+      end
+
+      def last_version
+        last_migration.version
+      end
+
+      def last_migration #:nodoc:
+        migrations(migrations_paths).last || NullMigration.new
+      end
+
+      def migrations_paths
+        @migrations_paths ||= ['db/migrate']
+        # just to not break things if someone uses: migration_path = some_string
+        Array(@migrations_paths)
+      end
+
+      def migrations_path
+        migrations_paths.first
+      end
+
+      def migrations(paths)
+        paths = Array(paths)
+
+        files = Dir[*paths.map { |p| "#{p}/**/[0-9]*_*.rb" }]
+
+        migrations = files.map do |file|
+          version, name, scope = file.scan(/([0-9]+)_([_a-z0-9]*)\.?([_a-z0-9]*)?\.rb\z/).first
+
+          raise IllegalMigrationNameError.new(file) unless version
+          version = version.to_i
+          name = name.camelize
+
+          MigrationProxy.new(name, version, file, scope)
+        end
+
+        migrations.sort_by(&:version)
+      end
+
+      private
+
+      def move(direction, migrations_paths, steps)
+        migrator = new(direction, migrations(migrations_paths))
+        start_index = migrator.migrations.index(migrator.current_migration)
+
+        if start_index
+          finish = migrator.migrations[start_index + steps]
+          version = finish ? finish.version : 0
+          send(direction, migrations_paths, version)
+        end
+      end
+    end
+
+    def initialize(direction, migrations, target_version = nil)
+      raise StandardError.new("This database does not yet support migrations") unless Base.connection.supports_migrations?
+
+      @direction         = direction
+      @target_version    = target_version
+      @migrated_versions = nil
+      @migrations        = migrations
+
+      validate(@migrations)
+
+      Base.connection.initialize_schema_migrations_table
+    end
+
+    def current_version
+      migrated.max || 0
+    end
+
+    def current_migration
+      migrations.detect { |m| m.version == current_version }
+    end
+    alias :current :current_migration
+
+    def run
+      migration = migrations.detect { |m| m.version == @target_version }
+      raise UnknownMigrationVersionError.new(@target_version) if migration.nil?
+      unless (up? && migrated.include?(migration.version.to_i)) || (down? && !migrated.include?(migration.version.to_i))
+        begin
+          execute_migration_in_transaction(migration, @direction)
+        rescue => e
+          canceled_msg = use_transaction?(migration) ? ", this migration was canceled" : ""
+          raise StandardError, "An error has occurred#{canceled_msg}:\n\n#{e}", e.backtrace
+        end
+      end
+    end
+
+    def migrate
+      if !target && @target_version && @target_version > 0
+        raise UnknownMigrationVersionError.new(@target_version)
+      end
+
+      runnable.each do |migration|
+        Base.logger.info "Migrating to #{migration.name} (#{migration.version})" if Base.logger
+
+        begin
+          execute_migration_in_transaction(migration, @direction)
+        rescue => e
+          canceled_msg = use_transaction?(migration) ? "this and " : ""
+          raise StandardError, "An error has occurred, #{canceled_msg}all later migrations canceled:\n\n#{e}", e.backtrace
+        end
+      end
+    end
+
+    def runnable
+      runnable = migrations[start..finish]
+      if up?
+        runnable.reject { |m| ran?(m) }
+      else
+        # skip the last migration if we're headed down, but not ALL the way down
+        runnable.pop if target
+        runnable.find_all { |m| ran?(m) }
+      end
+    end
+
+    def migrations
+      down? ? @migrations.reverse : @migrations.sort_by(&:version)
+    end
+
+    def pending_migrations
+      already_migrated = migrated
+      migrations.reject { |m| already_migrated.include?(m.version) }
+    end
+
+    def migrated
+      @migrated_versions ||= Set.new(self.class.get_all_versions)
+    end
+
+    private
+    def ran?(migration)
+      migrated.include?(migration.version.to_i)
+    end
+
+    def execute_migration_in_transaction(migration, direction)
+      ddl_transaction(migration) do
+        migration.migrate(direction)
+        record_version_state_after_migrating(migration.version)
+      end
+    end
+
+    def target
+      migrations.detect { |m| m.version == @target_version }
+    end
+
+    def finish
+      migrations.index(target) || migrations.size - 1
+    end
+
+    def start
+      up? ? 0 : (migrations.index(current) || 0)
+    end
+
+    def validate(migrations)
+      name ,= migrations.group_by(&:name).find { |_,v| v.length > 1 }
+      raise DuplicateMigrationNameError.new(name) if name
+
+      version ,= migrations.group_by(&:version).find { |_,v| v.length > 1 }
+      raise DuplicateMigrationVersionError.new(version) if version
+    end
+
+    def record_version_state_after_migrating(version)
+      if down?
+        migrated.delete(version)
+        ActiveRecord::SchemaMigration.where(:version => version.to_s).delete_all
+      else
+        migrated << version
+        ActiveRecord::SchemaMigration.create!(:version => version.to_s)
+      end
+    end
+
+    def up?
+      @direction == :up
+    end
+
+    def down?
+      @direction == :down
+    end
+
+    # Wrap the migration in a transaction only if supported by the adapter.
+    def ddl_transaction(migration)
+      if use_transaction?(migration)
+        Base.transaction { yield }
+      else
+        yield
+      end
+    end
+
+    def use_transaction?(migration)
+      !migration.disable_ddl_transaction && Base.connection.supports_ddl_transactions?
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/migration/command_recorder.rb b/activerecord/lib/active_record/migration/command_recorder.rb
new file mode 100644
index 0000000000..36256415df
--- /dev/null
+++ b/activerecord/lib/active_record/migration/command_recorder.rb
@@ -0,0 +1,197 @@
+module ActiveRecord
+  class Migration
+    # <tt>ActiveRecord::Migration::CommandRecorder</tt> records commands done during
+    # a migration and knows how to reverse those commands. The CommandRecorder
+    # knows how to invert the following commands:
+    #
+    # * add_column
+    # * add_index
+    # * add_timestamps
+    # * create_table
+    # * create_join_table
+    # * remove_timestamps
+    # * rename_column
+    # * rename_index
+    # * rename_table
+    class CommandRecorder
+      include JoinTable
+
+      attr_accessor :commands, :delegate, :reverting
+
+      def initialize(delegate = nil)
+        @commands = []
+        @delegate = delegate
+        @reverting = false
+      end
+
+      # While executing the given block, the recorded will be in reverting mode.
+      # All commands recorded will end up being recorded reverted
+      # and in reverse order.
+      # For example:
+      #
+      #   recorder.revert{ recorder.record(:rename_table, [:old, :new]) }
+      #   # same effect as recorder.record(:rename_table, [:new, :old])
+      def revert
+        @reverting = !@reverting
+        previous = @commands
+        @commands = []
+        yield
+      ensure
+        @commands = previous.concat(@commands.reverse)
+        @reverting = !@reverting
+      end
+
+      # record +command+. +command+ should be a method name and arguments.
+      # For example:
+      #
+      #   recorder.record(:method_name, [:arg1, :arg2])
+      def record(*command, &block)
+        if @reverting
+          @commands << inverse_of(*command, &block)
+        else
+          @commands << (command << block)
+        end
+      end
+
+      # Returns the inverse of the given command. For example:
+      #
+      #   recorder.inverse_of(:rename_table, [:old, :new])
+      #   # => [:rename_table, [:new, :old]]
+      #
+      # This method will raise an +IrreversibleMigration+ exception if it cannot
+      # invert the +command+.
+      def inverse_of(command, args, &block)
+        method = :"invert_#{command}"
+        raise IrreversibleMigration unless respond_to?(method, true)
+        send(method, args, &block)
+      end
+
+      def respond_to?(*args) # :nodoc:
+        super || delegate.respond_to?(*args)
+      end
+
+      [:create_table, :create_join_table, :rename_table, :add_column, :remove_column,
+        :rename_index, :rename_column, :add_index, :remove_index, :add_timestamps, :remove_timestamps,
+        :change_column_default, :add_reference, :remove_reference, :transaction,
+        :drop_join_table, :drop_table, :execute_block, :enable_extension,
+        :change_column, :execute, :remove_columns, :change_column_null,
+        :add_foreign_key, :remove_foreign_key
+       # irreversible methods need to be here too
+      ].each do |method|
+        class_eval <<-EOV, __FILE__, __LINE__ + 1
+          def #{method}(*args, &block)          # def create_table(*args, &block)
+            record(:"#{method}", args, &block)  #   record(:create_table, args, &block)
+          end                                   # end
+        EOV
+      end
+      alias :add_belongs_to :add_reference
+      alias :remove_belongs_to :remove_reference
+
+      def change_table(table_name, options = {}) # :nodoc:
+        yield delegate.update_table_definition(table_name, self)
+      end
+
+      private
+
+      module StraightReversions
+        private
+        { transaction:       :transaction,
+          execute_block:     :execute_block,
+          create_table:      :drop_table,
+          create_join_table: :drop_join_table,
+          add_column:        :remove_column,
+          add_timestamps:    :remove_timestamps,
+          add_reference:     :remove_reference,
+          enable_extension:  :disable_extension
+        }.each do |cmd, inv|
+          [[inv, cmd], [cmd, inv]].uniq.each do |method, inverse|
+            class_eval <<-EOV, __FILE__, __LINE__ + 1
+              def invert_#{method}(args, &block)    # def invert_create_table(args, &block)
+                [:#{inverse}, args, block]          #   [:drop_table, args, block]
+              end                                   # end
+            EOV
+          end
+        end
+      end
+
+      include StraightReversions
+
+      def invert_drop_table(args, &block)
+        if args.size == 1 && block == nil
+          raise ActiveRecord::IrreversibleMigration, "To avoid mistakes, drop_table is only reversible if given options or a block (can be empty)."
+        end
+        super
+      end
+
+      def invert_rename_table(args)
+        [:rename_table, args.reverse]
+      end
+
+      def invert_remove_column(args)
+        raise ActiveRecord::IrreversibleMigration, "remove_column is only reversible if given a type." if args.size <= 2
+        super
+      end
+
+      def invert_rename_index(args)
+        [:rename_index, [args.first] + args.last(2).reverse]
+      end
+
+      def invert_rename_column(args)
+        [:rename_column, [args.first] + args.last(2).reverse]
+      end
+
+      def invert_add_index(args)
+        table, columns, options = *args
+        options ||= {}
+
+        index_name = options[:name]
+        options_hash = index_name ? { name: index_name } : { column: columns }
+
+        [:remove_index, [table, options_hash]]
+      end
+
+      def invert_remove_index(args)
+        table, options = *args
+
+        unless options && options.is_a?(Hash) && options[:column]
+          raise ActiveRecord::IrreversibleMigration, "remove_index is only reversible if given a :column option."
+        end
+
+        options = options.dup
+        [:add_index, [table, options.delete(:column), options]]
+      end
+
+      alias :invert_add_belongs_to :invert_add_reference
+      alias :invert_remove_belongs_to :invert_remove_reference
+
+      def invert_change_column_null(args)
+        args[2] = !args[2]
+        [:change_column_null, args]
+      end
+
+      def invert_add_foreign_key(args)
+        from_table, to_table, add_options = args
+        add_options ||= {}
+
+        if add_options[:name]
+          options = { name: add_options[:name] }
+        elsif add_options[:column]
+          options = { column: add_options[:column] }
+        else
+          options = to_table
+        end
+
+        [:remove_foreign_key, [from_table, options]]
+      end
+
+      # Forwards any missing method call to the \target.
+      def method_missing(method, *args, &block)
+        if @delegate.respond_to?(method)
+          @delegate.send(method, *args, &block)
+        else
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/migration/join_table.rb b/activerecord/lib/active_record/migration/join_table.rb
new file mode 100644
index 0000000000..05569fadbd
--- /dev/null
+++ b/activerecord/lib/active_record/migration/join_table.rb
@@ -0,0 +1,15 @@
+module ActiveRecord
+  class Migration
+    module JoinTable #:nodoc:
+      private
+
+      def find_join_table_name(table_1, table_2, options = {})
+        options.delete(:table_name) || join_table_name(table_1, table_2)
+      end
+
+      def join_table_name(table_1, table_2)
+        ModelSchema.derive_join_table_name(table_1, table_2).to_sym
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
new file mode 100644
index 0000000000..850220babd
--- /dev/null
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -0,0 +1,339 @@
+module ActiveRecord
+  module ModelSchema
+    extend ActiveSupport::Concern
+
+    included do
+      ##
+      # :singleton-method:
+      # Accessor for the prefix type that will be prepended to every primary key column name.
+      # The options are :table_name and :table_name_with_underscore. If the first is specified,
+      # the Product class will look for "productid" instead of "id" as the primary column. If the
+      # latter is specified, the Product class will look for "product_id" instead of "id". Remember
+      # that this is a global setting for all Active Records.
+      mattr_accessor :primary_key_prefix_type, instance_writer: false
+
+      ##
+      # :singleton-method:
+      # Accessor for the name of the prefix string to prepend to every table name. So if set
+      # to "basecamp_", all table names will be named like "basecamp_projects", "basecamp_people",
+      # etc. This is a convenient way of creating a namespace for tables in a shared database.
+      # By default, the prefix is the empty string.
+      #
+      # If you are organising your models within modules you can add a prefix to the models within
+      # a namespace by defining a singleton method in the parent module called table_name_prefix which
+      # returns your chosen prefix.
+      class_attribute :table_name_prefix, instance_writer: false
+      self.table_name_prefix = ""
+
+      ##
+      # :singleton-method:
+      # Works like +table_name_prefix+, but appends instead of prepends (set to "_basecamp" gives "projects_basecamp",
+      # "people_basecamp"). By default, the suffix is the empty string.
+      #
+      # If you are organising your models within modules, you can add a suffix to the models within
+      # a namespace by defining a singleton method in the parent module called table_name_suffix which
+      # returns your chosen suffix.
+      class_attribute :table_name_suffix, instance_writer: false
+      self.table_name_suffix = ""
+
+      ##
+      # :singleton-method:
+      # Accessor for the name of the schema migrations table. By default, the value is "schema_migrations"
+      class_attribute :schema_migrations_table_name, instance_accessor: false
+      self.schema_migrations_table_name = "schema_migrations"
+
+      ##
+      # :singleton-method:
+      # Indicates whether table names should be the pluralized versions of the corresponding class names.
+      # If true, the default table name for a Product class will be +products+. If false, it would just be +product+.
+      # See table_name for the full rules on table/class naming. This is true, by default.
+      class_attribute :pluralize_table_names, instance_writer: false
+      self.pluralize_table_names = true
+
+      self.inheritance_column = 'type'
+
+      delegate :type_for_attribute, to: :class
+    end
+
+    # Derives the join table name for +first_table+ and +second_table+. The
+    # table names appear in alphabetical order. A common prefix is removed
+    # (useful for namespaced models like Music::Artist and Music::Record):
+    #
+    #   artists, records => artists_records
+    #   records, artists => artists_records
+    #   music_artists, music_records => music_artists_records
+    def self.derive_join_table_name(first_table, second_table) # :nodoc:
+      [first_table.to_s, second_table.to_s].sort.join("\0").gsub(/^(.*_)(.+)\0\1(.+)/, '\1\2_\3').gsub("\0", "_")
+    end
+
+    module ClassMethods
+      # Guesses the table name (in forced lower-case) based on the name of the class in the
+      # inheritance hierarchy descending directly from ActiveRecord::Base. So if the hierarchy
+      # looks like: Reply < Message < ActiveRecord::Base, then Message is used
+      # to guess the table name even when called on Reply. The rules used to do the guess
+      # are handled by the Inflector class in Active Support, which knows almost all common
+      # English inflections. You can add new inflections in config/initializers/inflections.rb.
+      #
+      # Nested classes are given table names prefixed by the singular form of
+      # the parent's table name. Enclosing modules are not considered.
+      #
+      # ==== Examples
+      #
+      #   class Invoice < ActiveRecord::Base
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice.rb            Invoice             invoices
+      #
+      #   class Invoice < ActiveRecord::Base
+      #     class Lineitem < ActiveRecord::Base
+      #     end
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice.rb            Invoice::Lineitem   invoice_lineitems
+      #
+      #   module Invoice
+      #     class Lineitem < ActiveRecord::Base
+      #     end
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice/lineitem.rb   Invoice::Lineitem   lineitems
+      #
+      # Additionally, the class-level +table_name_prefix+ is prepended and the
+      # +table_name_suffix+ is appended. So if you have "myapp_" as a prefix,
+      # the table name guess for an Invoice class becomes "myapp_invoices".
+      # Invoice::Lineitem becomes "myapp_invoice_lineitems".
+      #
+      # You can also set your own table name explicitly:
+      #
+      #   class Mouse < ActiveRecord::Base
+      #     self.table_name = "mice"
+      #   end
+      #
+      # Alternatively, you can override the table_name method to define your
+      # own computation. (Possibly using <tt>super</tt> to manipulate the default
+      # table name.) Example:
+      #
+      #   class Post < ActiveRecord::Base
+      #     def self.table_name
+      #       "special_" + super
+      #     end
+      #   end
+      #   Post.table_name # => "special_posts"
+      def table_name
+        reset_table_name unless defined?(@table_name)
+        @table_name
+      end
+
+      # Sets the table name explicitly. Example:
+      #
+      #   class Project < ActiveRecord::Base
+      #     self.table_name = "project"
+      #   end
+      #
+      # You can also just define your own <tt>self.table_name</tt> method; see
+      # the documentation for ActiveRecord::Base#table_name.
+      def table_name=(value)
+        value = value && value.to_s
+
+        if defined?(@table_name)
+          return if value == @table_name
+          reset_column_information if connected?
+        end
+
+        @table_name        = value
+        @quoted_table_name = nil
+        @arel_table        = nil
+        @sequence_name     = nil unless defined?(@explicit_sequence_name) && @explicit_sequence_name
+        @relation          = Relation.create(self, arel_table)
+      end
+
+      # Returns a quoted version of the table name, used to construct SQL statements.
+      def quoted_table_name
+        @quoted_table_name ||= connection.quote_table_name(table_name)
+      end
+
+      # Computes the table name, (re)sets it internally, and returns it.
+      def reset_table_name #:nodoc:
+        self.table_name = if abstract_class?
+          superclass == Base ? nil : superclass.table_name
+        elsif superclass.abstract_class?
+          superclass.table_name || compute_table_name
+        else
+          compute_table_name
+        end
+      end
+
+      def full_table_name_prefix #:nodoc:
+        (parents.detect{ |p| p.respond_to?(:table_name_prefix) } || self).table_name_prefix
+      end
+
+      def full_table_name_suffix #:nodoc:
+        (parents.detect {|p| p.respond_to?(:table_name_suffix) } || self).table_name_suffix
+      end
+
+      # Defines the name of the table column which will store the class name on single-table
+      # inheritance situations.
+      #
+      # The default inheritance column name is +type+, which means it's a
+      # reserved word inside Active Record. To be able to use single-table
+      # inheritance with another column name, or to use the column +type+ in
+      # your own model for something else, you can set +inheritance_column+:
+      #
+      #     self.inheritance_column = 'zoink'
+      def inheritance_column
+        (@inheritance_column ||= nil) || superclass.inheritance_column
+      end
+
+      # Sets the value of inheritance_column
+      def inheritance_column=(value)
+        @inheritance_column = value.to_s
+        @explicit_inheritance_column = true
+      end
+
+      def sequence_name
+        if base_class == self
+          @sequence_name ||= reset_sequence_name
+        else
+          (@sequence_name ||= nil) || base_class.sequence_name
+        end
+      end
+
+      def reset_sequence_name #:nodoc:
+        @explicit_sequence_name = false
+        @sequence_name          = connection.default_sequence_name(table_name, primary_key)
+      end
+
+      # Sets the name of the sequence to use when generating ids to the given
+      # value, or (if the value is nil or false) to the value returned by the
+      # given block. This is required for Oracle and is useful for any
+      # database which relies on sequences for primary key generation.
+      #
+      # If a sequence name is not explicitly set when using Oracle,
+      # it will default to the commonly used pattern of: #{table_name}_seq
+      #
+      # If a sequence name is not explicitly set when using PostgreSQL, it
+      # will discover the sequence corresponding to your primary key for you.
+      #
+      #   class Project < ActiveRecord::Base
+      #     self.sequence_name = "projectseq"   # default would have been "project_seq"
+      #   end
+      def sequence_name=(value)
+        @sequence_name          = value.to_s
+        @explicit_sequence_name = true
+      end
+
+      # Indicates whether the table associated with this class exists
+      def table_exists?
+        connection.schema_cache.table_exists?(table_name)
+      end
+
+      def attributes_builder # :nodoc:
+        @attributes_builder ||= AttributeSet::Builder.new(column_types)
+      end
+
+      def column_types # :nodoc:
+        @column_types ||= columns_hash.transform_values(&:cast_type).tap do |h|
+          h.default = Type::Value.new
+        end
+      end
+
+      def type_for_attribute(attr_name) # :nodoc:
+        column_types[attr_name]
+      end
+
+      # Returns a hash where the keys are column names and the values are
+      # default values when instantiating the AR object for this table.
+      def column_defaults
+        default_attributes.to_hash
+      end
+
+      def default_attributes # :nodoc:
+        @default_attributes ||= attributes_builder.build_from_database(
+          columns_hash.transform_values(&:default))
+      end
+
+      # Returns an array of column names as strings.
+      def column_names
+        @column_names ||= columns.map { |column| column.name }
+      end
+
+      # Returns an array of column objects where the primary id, all columns ending in "_id" or "_count",
+      # and columns used for single table inheritance have been removed.
+      def content_columns
+        @content_columns ||= columns.reject { |c| c.name == primary_key || c.name =~ /(_id|_count)$/ || c.name == inheritance_column }
+      end
+
+      # Resets all the cached information about columns, which will cause them
+      # to be reloaded on the next request.
+      #
+      # The most common usage pattern for this method is probably in a migration,
+      # when just after creating a table you want to populate it with some default
+      # values, eg:
+      #
+      #  class CreateJobLevels < ActiveRecord::Migration
+      #    def up
+      #      create_table :job_levels do |t|
+      #        t.integer :id
+      #        t.string :name
+      #
+      #        t.timestamps
+      #      end
+      #
+      #      JobLevel.reset_column_information
+      #      %w{assistant executive manager director}.each do |type|
+      #        JobLevel.create(name: type)
+      #      end
+      #    end
+      #
+      #    def down
+      #      drop_table :job_levels
+      #    end
+      #  end
+      def reset_column_information
+        connection.clear_cache!
+        undefine_attribute_methods
+        connection.schema_cache.clear_table_cache!(table_name) if table_exists?
+
+        @arel_engine             = nil
+        @column_names            = nil
+        @column_types            = nil
+        @content_columns         = nil
+        @default_attributes      = nil
+        @dynamic_methods_hash    = nil
+        @inheritance_column      = nil unless defined?(@explicit_inheritance_column) && @explicit_inheritance_column
+        @relation                = nil
+        @time_zone_column_names  = nil
+        @cached_time_zone        = nil
+      end
+
+      private
+
+      # Guesses the table name, but does not decorate it with prefix and suffix information.
+      def undecorated_table_name(class_name = base_class.name)
+        table_name = class_name.to_s.demodulize.underscore
+        pluralize_table_names ? table_name.pluralize : table_name
+      end
+
+      # Computes and returns a table name according to default conventions.
+      def compute_table_name
+        base = base_class
+        if self == base
+          # Nested classes are prefixed with singular parent table name.
+          if parent < Base && !parent.abstract_class?
+            contained = parent.table_name
+            contained = contained.singularize if parent.pluralize_table_names
+            contained += '_'
+          end
+
+          "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{full_table_name_suffix}"
+        else
+          # STI subclasses always use their superclass' table.
+          base.table_name
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
new file mode 100644
index 0000000000..8a2a06f2ca
--- /dev/null
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -0,0 +1,548 @@
+require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/object/try'
+require 'active_support/core_ext/hash/indifferent_access'
+
+module ActiveRecord
+  module NestedAttributes #:nodoc:
+    class TooManyRecords < ActiveRecordError
+    end
+
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :nested_attributes_options, instance_writer: false
+      self.nested_attributes_options = {}
+    end
+
+    # = Active Record Nested Attributes
+    #
+    # Nested attributes allow you to save attributes on associated records
+    # through the parent. By default nested attribute updating is turned off
+    # and you can enable it using the accepts_nested_attributes_for class
+    # method. When you enable nested attributes an attribute writer is
+    # defined on the model.
+    #
+    # The attribute writer is named after the association, which means that
+    # in the following example, two new methods are added to your model:
+    #
+    # <tt>author_attributes=(attributes)</tt> and
+    # <tt>pages_attributes=(attributes)</tt>.
+    #
+    #   class Book < ActiveRecord::Base
+    #     has_one :author
+    #     has_many :pages
+    #
+    #     accepts_nested_attributes_for :author, :pages
+    #   end
+    #
+    # Note that the <tt>:autosave</tt> option is automatically enabled on every
+    # association that accepts_nested_attributes_for is used for.
+    #
+    # === One-to-one
+    #
+    # Consider a Member model that has one Avatar:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_one :avatar
+    #     accepts_nested_attributes_for :avatar
+    #   end
+    #
+    # Enabling nested attributes on a one-to-one association allows you to
+    # create the member and avatar in one go:
+    #
+    #   params = { member: { name: 'Jack', avatar_attributes: { icon: 'smiling' } } }
+    #   member = Member.create(params[:member])
+    #   member.avatar.id # => 2
+    #   member.avatar.icon # => 'smiling'
+    #
+    # It also allows you to update the avatar through the member:
+    #
+    #   params = { member: { avatar_attributes: { id: '2', icon: 'sad' } } }
+    #   member.update params[:member]
+    #   member.avatar.icon # => 'sad'
+    #
+    # By default you will only be able to set and update attributes on the
+    # associated model. If you want to destroy the associated model through the
+    # attributes hash, you have to enable it first using the
+    # <tt>:allow_destroy</tt> option.
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_one :avatar
+    #     accepts_nested_attributes_for :avatar, allow_destroy: true
+    #   end
+    #
+    # Now, when you add the <tt>_destroy</tt> key to the attributes hash, with a
+    # value that evaluates to +true+, you will destroy the associated model:
+    #
+    #   member.avatar_attributes = { id: '2', _destroy: '1' }
+    #   member.avatar.marked_for_destruction? # => true
+    #   member.save
+    #   member.reload.avatar # => nil
+    #
+    # Note that the model will _not_ be destroyed until the parent is saved.
+    #
+    # === One-to-many
+    #
+    # Consider a member that has a number of posts:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts
+    #   end
+    #
+    # You can now set or update attributes on the associated posts through
+    # an attribute hash for a member: include the key +:posts_attributes+
+    # with an array of hashes of post attributes as a value.
+    #
+    # For each hash that does _not_ have an <tt>id</tt> key a new record will
+    # be instantiated, unless the hash also contains a <tt>_destroy</tt> key
+    # that evaluates to +true+.
+    #
+    #   params = { member: {
+    #     name: 'joe', posts_attributes: [
+    #       { title: 'Kari, the awesome Ruby documentation browser!' },
+    #       { title: 'The egalitarian assumption of the modern citizen' },
+    #       { title: '', _destroy: '1' } # this will be ignored
+    #     ]
+    #   }}
+    #
+    #   member = Member.create(params[:member])
+    #   member.posts.length # => 2
+    #   member.posts.first.title # => 'Kari, the awesome Ruby documentation browser!'
+    #   member.posts.second.title # => 'The egalitarian assumption of the modern citizen'
+    #
+    # You may also set a :reject_if proc to silently ignore any new record
+    # hashes if they fail to pass your criteria. For example, the previous
+    # example could be rewritten as:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, reject_if: proc { |attributes| attributes['title'].blank? }
+    #   end
+    #
+    #   params = { member: {
+    #     name: 'joe', posts_attributes: [
+    #       { title: 'Kari, the awesome Ruby documentation browser!' },
+    #       { title: 'The egalitarian assumption of the modern citizen' },
+    #       { title: '' } # this will be ignored because of the :reject_if proc
+    #     ]
+    #   }}
+    #
+    #   member = Member.create(params[:member])
+    #   member.posts.length # => 2
+    #   member.posts.first.title # => 'Kari, the awesome Ruby documentation browser!'
+    #   member.posts.second.title # => 'The egalitarian assumption of the modern citizen'
+    #
+    # Alternatively, :reject_if also accepts a symbol for using methods:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, reject_if: :new_record?
+    #   end
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, reject_if: :reject_posts
+    #
+    #     def reject_posts(attributed)
+    #       attributed['title'].blank?
+    #     end
+    #   end
+    #
+    # If the hash contains an <tt>id</tt> key that matches an already
+    # associated record, the matching record will be modified:
+    #
+    #   member.attributes = {
+    #     name: 'Joe',
+    #     posts_attributes: [
+    #       { id: 1, title: '[UPDATED] An, as of yet, undisclosed awesome Ruby documentation browser!' },
+    #       { id: 2, title: '[UPDATED] other post' }
+    #     ]
+    #   }
+    #
+    #   member.posts.first.title # => '[UPDATED] An, as of yet, undisclosed awesome Ruby documentation browser!'
+    #   member.posts.second.title # => '[UPDATED] other post'
+    #
+    # By default the associated records are protected from being destroyed. If
+    # you want to destroy any of the associated records through the attributes
+    # hash, you have to enable it first using the <tt>:allow_destroy</tt>
+    # option. This will allow you to also use the <tt>_destroy</tt> key to
+    # destroy existing records:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, allow_destroy: true
+    #   end
+    #
+    #   params = { member: {
+    #     posts_attributes: [{ id: '2', _destroy: '1' }]
+    #   }}
+    #
+    #   member.attributes = params[:member]
+    #   member.posts.detect { |p| p.id == 2 }.marked_for_destruction? # => true
+    #   member.posts.length # => 2
+    #   member.save
+    #   member.reload.posts.length # => 1
+    #
+    # Nested attributes for an associated collection can also be passed in
+    # the form of a hash of hashes instead of an array of hashes:
+    #
+    #   Member.create(name:             'joe',
+    #                 posts_attributes: { first:  { title: 'Foo' },
+    #                                     second: { title: 'Bar' } })
+    #
+    # has the same effect as
+    #
+    #   Member.create(name:             'joe',
+    #                 posts_attributes: [ { title: 'Foo' },
+    #                                     { title: 'Bar' } ])
+    #
+    # The keys of the hash which is the value for +:posts_attributes+ are
+    # ignored in this case.
+    # However, it is not allowed to use +'id'+ or +:id+ for one of
+    # such keys, otherwise the hash will be wrapped in an array and
+    # interpreted as an attribute hash for a single post.
+    #
+    # Passing attributes for an associated collection in the form of a hash
+    # of hashes can be used with hashes generated from HTTP/HTML parameters,
+    # where there maybe no natural way to submit an array of hashes.
+    #
+    # === Saving
+    #
+    # All changes to models, including the destruction of those marked for
+    # destruction, are saved and destroyed automatically and atomically when
+    # the parent model is saved. This happens inside the transaction initiated
+    # by the parents save method. See ActiveRecord::AutosaveAssociation.
+    #
+    # === Validating the presence of a parent model
+    #
+    # If you want to validate that a child record is associated with a parent
+    # record, you can use <tt>validates_presence_of</tt> and
+    # <tt>inverse_of</tt> as this example illustrates:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts, inverse_of: :member
+    #     accepts_nested_attributes_for :posts
+    #   end
+    #
+    #   class Post < ActiveRecord::Base
+    #     belongs_to :member, inverse_of: :posts
+    #     validates_presence_of :member
+    #   end
+    #
+    # Note that if you do not specify the <tt>inverse_of</tt> option, then
+    # Active Record will try to automatically guess the inverse association
+    # based on heuristics.
+    #
+    # For one-to-one nested associations, if you build the new (in-memory)
+    # child object yourself before assignment, then this module will not
+    # overwrite it, e.g.:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_one :avatar
+    #     accepts_nested_attributes_for :avatar
+    #
+    #     def avatar
+    #       super || build_avatar(width: 200)
+    #     end
+    #   end
+    #
+    #   member = Member.new
+    #   member.avatar_attributes = {icon: 'sad'}
+    #   member.avatar.width # => 200
+    module ClassMethods
+      REJECT_ALL_BLANK_PROC = proc { |attributes| attributes.all? { |key, value| key == '_destroy' || value.blank? } }
+
+      # Defines an attributes writer for the specified association(s).
+      #
+      # Supported options:
+      # [:allow_destroy]
+      #   If true, destroys any members from the attributes hash with a
+      #   <tt>_destroy</tt> key and a value that evaluates to +true+
+      #   (eg. 1, '1', true, or 'true'). This option is off by default.
+      # [:reject_if]
+      #   Allows you to specify a Proc or a Symbol pointing to a method
+      #   that checks whether a record should be built for a certain attribute
+      #   hash. The hash is passed to the supplied Proc or the method
+      #   and it should return either +true+ or +false+. When no :reject_if
+      #   is specified, a record will be built for all attribute hashes that
+      #   do not have a <tt>_destroy</tt> value that evaluates to true.
+      #   Passing <tt>:all_blank</tt> instead of a Proc will create a proc
+      #   that will reject a record where all the attributes are blank excluding
+      #   any value for _destroy.
+      # [:limit]
+      #   Allows you to specify the maximum number of the associated records that
+      #   can be processed with the nested attributes. Limit also can be specified as a
+      #   Proc or a Symbol pointing to a method that should return number. If the size of the
+      #   nested attributes array exceeds the specified limit, NestedAttributes::TooManyRecords
+      #   exception is raised. If omitted, any number associations can be processed.
+      #   Note that the :limit option is only applicable to one-to-many associations.
+      # [:update_only]
+      #   For a one-to-one association, this option allows you to specify how
+      #   nested attributes are to be used when an associated record already
+      #   exists. In general, an existing record may either be updated with the
+      #   new set of attribute values or be replaced by a wholly new record
+      #   containing those values. By default the :update_only option is +false+
+      #   and the nested attributes are used to update the existing record only
+      #   if they include the record's <tt>:id</tt> value. Otherwise a new
+      #   record will be instantiated and used to replace the existing one.
+      #   However if the :update_only option is +true+, the nested attributes
+      #   are used to update the record's attributes always, regardless of
+      #   whether the <tt>:id</tt> is present. The option is ignored for collection
+      #   associations.
+      #
+      # Examples:
+      #   # creates avatar_attributes=
+      #   accepts_nested_attributes_for :avatar, reject_if: proc { |attributes| attributes['name'].blank? }
+      #   # creates avatar_attributes=
+      #   accepts_nested_attributes_for :avatar, reject_if: :all_blank
+      #   # creates avatar_attributes= and posts_attributes=
+      #   accepts_nested_attributes_for :avatar, :posts, allow_destroy: true
+      def accepts_nested_attributes_for(*attr_names)
+        options = { :allow_destroy => false, :update_only => false }
+        options.update(attr_names.extract_options!)
+        options.assert_valid_keys(:allow_destroy, :reject_if, :limit, :update_only)
+        options[:reject_if] = REJECT_ALL_BLANK_PROC if options[:reject_if] == :all_blank
+
+        attr_names.each do |association_name|
+          if reflection = _reflect_on_association(association_name)
+            reflection.autosave = true
+            add_autosave_association_callbacks(reflection)
+
+            nested_attributes_options = self.nested_attributes_options.dup
+            nested_attributes_options[association_name.to_sym] = options
+            self.nested_attributes_options = nested_attributes_options
+
+            type = (reflection.collection? ? :collection : :one_to_one)
+            generate_association_writer(association_name, type)
+          else
+            raise ArgumentError, "No association found for name `#{association_name}'. Has it been defined yet?"
+          end
+        end
+      end
+
+      private
+
+      # Generates a writer method for this association. Serves as a point for
+      # accessing the objects in the association. For example, this method
+      # could generate the following:
+      #
+      #   def pirate_attributes=(attributes)
+      #     assign_nested_attributes_for_one_to_one_association(:pirate, attributes)
+      #   end
+      #
+      # This redirects the attempts to write objects in an association through
+      # the helper methods defined below. Makes it seem like the nested
+      # associations are just regular associations.
+      def generate_association_writer(association_name, type)
+        generated_association_methods.module_eval <<-eoruby, __FILE__, __LINE__ + 1
+          if method_defined?(:#{association_name}_attributes=)
+            remove_method(:#{association_name}_attributes=)
+          end
+          def #{association_name}_attributes=(attributes)
+            assign_nested_attributes_for_#{type}_association(:#{association_name}, attributes)
+          end
+        eoruby
+      end
+    end
+
+    # Returns ActiveRecord::AutosaveAssociation::marked_for_destruction? It's
+    # used in conjunction with fields_for to build a form element for the
+    # destruction of this association.
+    #
+    # See ActionView::Helpers::FormHelper::fields_for for more info.
+    def _destroy
+      marked_for_destruction?
+    end
+
+    private
+
+    # Attribute hash keys that should not be assigned as normal attributes.
+    # These hash keys are nested attributes implementation details.
+    UNASSIGNABLE_KEYS = %w( id _destroy )
+
+    # Assigns the given attributes to the association.
+    #
+    # If an associated record does not yet exist, one will be instantiated. If
+    # an associated record already exists, the method's behavior depends on
+    # the value of the update_only option. If update_only is +false+ and the
+    # given attributes include an <tt>:id</tt> that matches the existing record's
+    # id, then the existing record will be modified. If no <tt>:id</tt> is provided
+    # it will be replaced with a new record. If update_only is +true+ the existing
+    # record will be modified regardless of whether an <tt>:id</tt> is provided.
+    #
+    # If the given attributes include a matching <tt>:id</tt> attribute, or
+    # update_only is true, and a <tt>:_destroy</tt> key set to a truthy value,
+    # then the existing record will be marked for destruction.
+    def assign_nested_attributes_for_one_to_one_association(association_name, attributes)
+      options = self.nested_attributes_options[association_name]
+      attributes = attributes.with_indifferent_access
+      existing_record = send(association_name)
+
+      if (options[:update_only] || !attributes['id'].blank?) && existing_record &&
+          (options[:update_only] || existing_record.id.to_s == attributes['id'].to_s)
+        assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy]) unless call_reject_if(association_name, attributes)
+
+      elsif attributes['id'].present?
+        raise_nested_attributes_record_not_found!(association_name, attributes['id'])
+
+      elsif !reject_new_record?(association_name, attributes)
+        assignable_attributes = attributes.except(*UNASSIGNABLE_KEYS)
+
+        if existing_record && existing_record.new_record?
+          existing_record.assign_attributes(assignable_attributes)
+          association(association_name).initialize_attributes(existing_record)
+        else
+          method = "build_#{association_name}"
+          if respond_to?(method)
+            send(method, assignable_attributes)
+          else
+            raise ArgumentError, "Cannot build association `#{association_name}'. Are you trying to build a polymorphic one-to-one association?"
+          end
+        end
+      end
+    end
+
+    # Assigns the given attributes to the collection association.
+    #
+    # Hashes with an <tt>:id</tt> value matching an existing associated record
+    # will update that record. Hashes without an <tt>:id</tt> value will build
+    # a new record for the association. Hashes with a matching <tt>:id</tt>
+    # value and a <tt>:_destroy</tt> key set to a truthy value will mark the
+    # matched record for destruction.
+    #
+    # For example:
+    #
+    #   assign_nested_attributes_for_collection_association(:people, {
+    #     '1' => { id: '1', name: 'Peter' },
+    #     '2' => { name: 'John' },
+    #     '3' => { id: '2', _destroy: true }
+    #   })
+    #
+    # Will update the name of the Person with ID 1, build a new associated
+    # person with the name 'John', and mark the associated Person with ID 2
+    # for destruction.
+    #
+    # Also accepts an Array of attribute hashes:
+    #
+    #   assign_nested_attributes_for_collection_association(:people, [
+    #     { id: '1', name: 'Peter' },
+    #     { name: 'John' },
+    #     { id: '2', _destroy: true }
+    #   ])
+    def assign_nested_attributes_for_collection_association(association_name, attributes_collection)
+      options = self.nested_attributes_options[association_name]
+
+      unless attributes_collection.is_a?(Hash) || attributes_collection.is_a?(Array)
+        raise ArgumentError, "Hash or Array expected, got #{attributes_collection.class.name} (#{attributes_collection.inspect})"
+      end
+
+      check_record_limit!(options[:limit], attributes_collection)
+
+      if attributes_collection.is_a? Hash
+        keys = attributes_collection.keys
+        attributes_collection = if keys.include?('id') || keys.include?(:id)
+          [attributes_collection]
+        else
+          attributes_collection.values
+        end
+      end
+
+      association = association(association_name)
+
+      existing_records = if association.loaded?
+        association.target
+      else
+        attribute_ids = attributes_collection.map {|a| a['id'] || a[:id] }.compact
+        attribute_ids.empty? ? [] : association.scope.where(association.klass.primary_key => attribute_ids)
+      end
+
+      attributes_collection.each do |attributes|
+        attributes = attributes.with_indifferent_access
+
+        if attributes['id'].blank?
+          unless reject_new_record?(association_name, attributes)
+            association.build(attributes.except(*UNASSIGNABLE_KEYS))
+          end
+        elsif existing_record = existing_records.detect { |record| record.id.to_s == attributes['id'].to_s }
+          unless call_reject_if(association_name, attributes)
+            # Make sure we are operating on the actual object which is in the association's
+            # proxy_target array (either by finding it, or adding it if not found)
+            # Take into account that the proxy_target may have changed due to callbacks
+            target_record = association.target.detect { |record| record.id.to_s == attributes['id'].to_s }
+            if target_record
+              existing_record = target_record
+            else
+              association.add_to_target(existing_record, :skip_callbacks)
+            end
+
+            assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy])
+          end
+        else
+          raise_nested_attributes_record_not_found!(association_name, attributes['id'])
+        end
+      end
+    end
+
+    # Takes in a limit and checks if the attributes_collection has too many
+    # records. It accepts limit in the form of symbol, proc, or
+    # number-like object (anything that can be compared with an integer).
+    #
+    # Raises TooManyRecords error if the attributes_collection is
+    # larger than the limit.
+    def check_record_limit!(limit, attributes_collection)
+      if limit
+        limit = case limit
+        when Symbol
+          send(limit)
+        when Proc
+          limit.call
+        else
+          limit
+        end
+
+        if limit && attributes_collection.size > limit
+          raise TooManyRecords, "Maximum #{limit} records are allowed. Got #{attributes_collection.size} records instead."
+        end
+      end
+    end
+
+    # Updates a record with the +attributes+ or marks it for destruction if
+    # +allow_destroy+ is +true+ and has_destroy_flag? returns +true+.
+    def assign_to_or_mark_for_destruction(record, attributes, allow_destroy)
+      record.assign_attributes(attributes.except(*UNASSIGNABLE_KEYS))
+      record.mark_for_destruction if has_destroy_flag?(attributes) && allow_destroy
+    end
+
+    # Determines if a hash contains a truthy _destroy key.
+    def has_destroy_flag?(hash)
+      Type::Boolean.new.type_cast_from_user(hash['_destroy'])
+    end
+
+    # Determines if a new record should be rejected by checking
+    # has_destroy_flag? or if a <tt>:reject_if</tt> proc exists for this
+    # association and evaluates to +true+.
+    def reject_new_record?(association_name, attributes)
+      has_destroy_flag?(attributes) || call_reject_if(association_name, attributes)
+    end
+
+    # Determines if a record with the particular +attributes+ should be
+    # rejected by calling the reject_if Symbol or Proc (if defined).
+    # The reject_if option is defined by +accepts_nested_attributes_for+.
+    #
+    # Returns false if there is a +destroy_flag+ on the attributes.
+    def call_reject_if(association_name, attributes)
+      return false if has_destroy_flag?(attributes)
+      case callback = self.nested_attributes_options[association_name][:reject_if]
+      when Symbol
+        method(callback).arity == 0 ? send(callback) : send(callback, attributes)
+      when Proc
+        callback.call(attributes)
+      end
+    end
+
+    def raise_nested_attributes_record_not_found!(association_name, record_id)
+      raise RecordNotFound, "Couldn't find #{self.class._reflect_on_association(association_name).klass.name} with ID=#{record_id} for #{self.class.name} with ID=#{id}"
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/no_touching.rb b/activerecord/lib/active_record/no_touching.rb
new file mode 100644
index 0000000000..dbf4564ae5
--- /dev/null
+++ b/activerecord/lib/active_record/no_touching.rb
@@ -0,0 +1,52 @@
+module ActiveRecord
+  # = Active Record No Touching
+  module NoTouching
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Lets you selectively disable calls to `touch` for the
+      # duration of a block.
+      #
+      # ==== Examples
+      #   ActiveRecord::Base.no_touching do
+      #     Project.first.touch  # does nothing
+      #     Message.first.touch  # does nothing
+      #   end
+      #
+      #   Project.no_touching do
+      #     Project.first.touch  # does nothing
+      #     Message.first.touch  # works, but does not touch the associated project
+      #   end
+      #
+      def no_touching(&block)
+        NoTouching.apply_to(self, &block)
+      end
+    end
+
+    class << self
+      def apply_to(klass) #:nodoc:
+        klasses.push(klass)
+        yield
+      ensure
+        klasses.pop
+      end
+
+      def applied_to?(klass) #:nodoc:
+        klasses.any? { |k| k >= klass }
+      end
+
+      private
+        def klasses
+          Thread.current[:no_touching_classes] ||= []
+        end
+    end
+
+    def no_touching?
+      NoTouching.applied_to?(self.class)
+    end
+
+    def touch(*)
+      super unless no_touching?
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/null_relation.rb b/activerecord/lib/active_record/null_relation.rb
new file mode 100644
index 0000000000..807c301596
--- /dev/null
+++ b/activerecord/lib/active_record/null_relation.rb
@@ -0,0 +1,81 @@
+# -*- coding: utf-8 -*-
+
+module ActiveRecord
+  module NullRelation # :nodoc:
+    def exec_queries
+      @records = []
+    end
+
+    def pluck(*column_names)
+      []
+    end
+
+    def delete_all(_conditions = nil)
+      0
+    end
+
+    def update_all(_updates, _conditions = nil, _options = {})
+      0
+    end
+
+    def delete(_id_or_array)
+      0
+    end
+
+    def size
+      calculate :size, nil
+    end
+
+    def empty?
+      true
+    end
+
+    def any?
+      false
+    end
+
+    def many?
+      false
+    end
+
+    def to_sql
+      ""
+    end
+
+    def count(*)
+      calculate :count, nil
+    end
+
+    def sum(*)
+      calculate :sum, nil
+    end
+
+    def average(*)
+      calculate :average, nil
+    end
+
+    def minimum(*)
+      calculate :minimum, nil
+    end
+
+    def maximum(*)
+      calculate :maximum, nil
+    end
+
+    def calculate(operation, _column_name, _options = {})
+      # TODO: Remove _options argument as soon we remove support to
+      # activerecord-deprecated_finders.
+      if [:count, :sum, :size].include? operation
+        group_values.any? ? Hash.new : 0
+      elsif [:average, :minimum, :maximum].include?(operation) && group_values.any?
+        Hash.new
+      else
+        nil
+      end
+    end
+
+    def exists?(_id = false)
+      false
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
new file mode 100644
index 0000000000..51b1931ed5
--- /dev/null
+++ b/activerecord/lib/active_record/persistence.rb
@@ -0,0 +1,532 @@
+module ActiveRecord
+  # = Active Record Persistence
+  module Persistence
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Creates an object (or multiple objects) and saves it to the database, if validations pass.
+      # The resulting object is returned whether the object was saved successfully to the database or not.
+      #
+      # The +attributes+ parameter can be either a Hash or an Array of Hashes. These Hashes describe the
+      # attributes on the objects that are to be created.
+      #
+      # ==== Examples
+      #   # Create a single new object
+      #   User.create(first_name: 'Jamie')
+      #
+      #   # Create an Array of new objects
+      #   User.create([{ first_name: 'Jamie' }, { first_name: 'Jeremy' }])
+      #
+      #   # Create a single object and pass it into a block to set other attributes.
+      #   User.create(first_name: 'Jamie') do |u|
+      #     u.is_admin = false
+      #   end
+      #
+      #   # Creating an Array of new objects using a block, where the block is executed for each object:
+      #   User.create([{ first_name: 'Jamie' }, { first_name: 'Jeremy' }]) do |u|
+      #     u.is_admin = false
+      #   end
+      def create(attributes = nil, &block)
+        if attributes.is_a?(Array)
+          attributes.collect { |attr| create(attr, &block) }
+        else
+          object = new(attributes, &block)
+          object.save
+          object
+        end
+      end
+
+      # Creates an object (or multiple objects) and saves it to the database,
+      # if validations pass. Raises a RecordInvalid error if validations fail,
+      # unlike Base#create.
+      #
+      # The +attributes+ parameter can be either a Hash or an Array of Hashes.
+      # These describe which attributes to be created on the object, or
+      # multiple objects when given an Array of Hashes.
+      def create!(attributes = nil, &block)
+        if attributes.is_a?(Array)
+          attributes.collect { |attr| create!(attr, &block) }
+        else
+          object = new(attributes, &block)
+          object.save!
+          object
+        end
+      end
+
+      # Given an attributes hash, +instantiate+ returns a new instance of
+      # the appropriate class. Accepts only keys as strings.
+      #
+      # For example, +Post.all+ may return Comments, Messages, and Emails
+      # by storing the record's subclass in a +type+ attribute. By calling
+      # +instantiate+ instead of +new+, finder methods ensure they get new
+      # instances of the appropriate class for each record.
+      #
+      # See +ActiveRecord::Inheritance#discriminate_class_for_record+ to see
+      # how this "single-table" inheritance mapping is implemented.
+      def instantiate(attributes, column_types = {})
+        klass = discriminate_class_for_record(attributes)
+        attributes = klass.attributes_builder.build_from_database(attributes, column_types)
+        klass.allocate.init_with('attributes' => attributes, 'new_record' => false)
+      end
+
+      private
+        # Called by +instantiate+ to decide which class to use for a new
+        # record instance.
+        #
+        # See +ActiveRecord::Inheritance#discriminate_class_for_record+ for
+        # the single-table inheritance discriminator.
+        def discriminate_class_for_record(record)
+          self
+        end
+    end
+
+    # Returns true if this object hasn't been saved yet -- that is, a record
+    # for the object doesn't exist in the database yet; otherwise, returns false.
+    def new_record?
+      sync_with_transaction_state
+      @new_record
+    end
+
+    # Returns true if this object has been destroyed, otherwise returns false.
+    def destroyed?
+      sync_with_transaction_state
+      @destroyed
+    end
+
+    # Returns true if the record is persisted, i.e. it's not a new record and it was
+    # not destroyed, otherwise returns false.
+    def persisted?
+      !(new_record? || destroyed?)
+    end
+
+    # Saves the model.
+    #
+    # If the model is new a record gets created in the database, otherwise
+    # the existing record gets updated.
+    #
+    # By default, save always run validations. If any of them fail the action
+    # is cancelled and +save+ returns +false+. However, if you supply
+    # validate: false, validations are bypassed altogether. See
+    # ActiveRecord::Validations for more information.
+    #
+    # There's a series of callbacks associated with +save+. If any of the
+    # <tt>before_*</tt> callbacks return +false+ the action is cancelled and
+    # +save+ returns +false+. See ActiveRecord::Callbacks for further
+    # details.
+    #
+    # Attributes marked as readonly are silently ignored if the record is
+    # being updated.
+    def save(*)
+      create_or_update
+    rescue ActiveRecord::RecordInvalid
+      false
+    end
+
+    # Saves the model.
+    #
+    # If the model is new a record gets created in the database, otherwise
+    # the existing record gets updated.
+    #
+    # With <tt>save!</tt> validations always run. If any of them fail
+    # ActiveRecord::RecordInvalid gets raised. See ActiveRecord::Validations
+    # for more information.
+    #
+    # There's a series of callbacks associated with <tt>save!</tt>. If any of
+    # the <tt>before_*</tt> callbacks return +false+ the action is cancelled
+    # and <tt>save!</tt> raises ActiveRecord::RecordNotSaved. See
+    # ActiveRecord::Callbacks for further details.
+    #
+    # Attributes marked as readonly are silently ignored if the record is
+    # being updated.
+    def save!(*)
+      create_or_update || raise(RecordNotSaved)
+    end
+
+    # Deletes the record in the database and freezes this instance to
+    # reflect that no changes should be made (since they can't be
+    # persisted). Returns the frozen instance.
+    #
+    # The row is simply removed with an SQL +DELETE+ statement on the
+    # record's primary key, and no callbacks are executed.
+    #
+    # To enforce the object's +before_destroy+ and +after_destroy+
+    # callbacks or any <tt>:dependent</tt> association
+    # options, use <tt>#destroy</tt>.
+    def delete
+      self.class.delete(id) if persisted?
+      @destroyed = true
+      freeze
+    end
+
+    # Deletes the record in the database and freezes this instance to reflect
+    # that no changes should be made (since they can't be persisted).
+    #
+    # There's a series of callbacks associated with <tt>destroy</tt>. If
+    # the <tt>before_destroy</tt> callback return +false+ the action is cancelled
+    # and <tt>destroy</tt> returns +false+. See
+    # ActiveRecord::Callbacks for further details.
+    def destroy
+      raise ReadOnlyRecord if readonly?
+      destroy_associations
+      destroy_row if persisted?
+      @destroyed = true
+      freeze
+    end
+
+    # Deletes the record in the database and freezes this instance to reflect
+    # that no changes should be made (since they can't be persisted).
+    #
+    # There's a series of callbacks associated with <tt>destroy!</tt>. If
+    # the <tt>before_destroy</tt> callback return +false+ the action is cancelled
+    # and <tt>destroy!</tt> raises ActiveRecord::RecordNotDestroyed. See
+    # ActiveRecord::Callbacks for further details.
+    def destroy!
+      destroy || raise(ActiveRecord::RecordNotDestroyed)
+    end
+
+    # Returns an instance of the specified +klass+ with the attributes of the
+    # current record. This is mostly useful in relation to single-table
+    # inheritance structures where you want a subclass to appear as the
+    # superclass. This can be used along with record identification in
+    # Action Pack to allow, say, <tt>Client < Company</tt> to do something
+    # like render <tt>partial: @client.becomes(Company)</tt> to render that
+    # instance using the companies/company partial instead of clients/client.
+    #
+    # Note: The new instance will share a link to the same attributes as the original class.
+    # So any change to the attributes in either instance will affect the other.
+    def becomes(klass)
+      became = klass.new
+      became.instance_variable_set("@attributes", @attributes)
+      became.instance_variable_set("@changed_attributes", @changed_attributes) if defined?(@changed_attributes)
+      became.instance_variable_set("@new_record", new_record?)
+      became.instance_variable_set("@destroyed", destroyed?)
+      became.instance_variable_set("@errors", errors)
+      became
+    end
+
+    # Wrapper around +becomes+ that also changes the instance's sti column value.
+    # This is especially useful if you want to persist the changed class in your
+    # database.
+    #
+    # Note: The old instance's sti column value will be changed too, as both objects
+    # share the same set of attributes.
+    def becomes!(klass)
+      became = becomes(klass)
+      sti_type = nil
+      if !klass.descends_from_active_record?
+        sti_type = klass.sti_name
+      end
+      became.public_send("#{klass.inheritance_column}=", sti_type)
+      became
+    end
+
+    # Updates a single attribute and saves the record.
+    # This is especially useful for boolean flags on existing records. Also note that
+    #
+    # * Validation is skipped.
+    # * Callbacks are invoked.
+    # * updated_at/updated_on column is updated if that column is available.
+    # * Updates all the attributes that are dirty in this object.
+    #
+    # This method raises an +ActiveRecord::ActiveRecordError+  if the
+    # attribute is marked as readonly.
+    #
+    # See also +update_column+.
+    def update_attribute(name, value)
+      name = name.to_s
+      verify_readonly_attribute(name)
+      send("#{name}=", value)
+      save(validate: false)
+    end
+
+    # Updates the attributes of the model from the passed-in hash and saves the
+    # record, all wrapped in a transaction. If the object is invalid, the saving
+    # will fail and false will be returned.
+    def update(attributes)
+      # The following transaction covers any possible database side-effects of the
+      # attributes assignment. For example, setting the IDs of a child collection.
+      with_transaction_returning_status do
+        assign_attributes(attributes)
+        save
+      end
+    end
+
+    alias update_attributes update
+
+    # Updates its receiver just like +update+ but calls <tt>save!</tt> instead
+    # of +save+, so an exception is raised if the record is invalid.
+    def update!(attributes)
+      # The following transaction covers any possible database side-effects of the
+      # attributes assignment. For example, setting the IDs of a child collection.
+      with_transaction_returning_status do
+        assign_attributes(attributes)
+        save!
+      end
+    end
+
+    alias update_attributes! update!
+
+    # Equivalent to <code>update_columns(name => value)</code>.
+    def update_column(name, value)
+      update_columns(name => value)
+    end
+
+    # Updates the attributes directly in the database issuing an UPDATE SQL
+    # statement and sets them in the receiver:
+    #
+    #   user.update_columns(last_request_at: Time.current)
+    #
+    # This is the fastest way to update attributes because it goes straight to
+    # the database, but take into account that in consequence the regular update
+    # procedures are totally bypassed. In particular:
+    #
+    # * Validations are skipped.
+    # * Callbacks are skipped.
+    # * +updated_at+/+updated_on+ are not updated.
+    #
+    # This method raises an +ActiveRecord::ActiveRecordError+ when called on new
+    # objects, or when at least one of the attributes is marked as readonly.
+    def update_columns(attributes)
+      raise ActiveRecordError, "cannot update a new record" if new_record?
+      raise ActiveRecordError, "cannot update a destroyed record" if destroyed?
+
+      attributes.each_key do |key|
+        verify_readonly_attribute(key.to_s)
+      end
+
+      updated_count = self.class.unscoped.where(self.class.primary_key => id).update_all(attributes)
+
+      attributes.each do |k, v|
+        raw_write_attribute(k, v)
+      end
+
+      updated_count == 1
+    end
+
+    # Initializes +attribute+ to zero if +nil+ and adds the value passed as +by+ (default is 1).
+    # The increment is performed directly on the underlying attribute, no setter is invoked.
+    # Only makes sense for number-based attributes. Returns +self+.
+    def increment(attribute, by = 1)
+      self[attribute] ||= 0
+      self[attribute] += by
+      self
+    end
+
+    # Wrapper around +increment+ that saves the record. This method differs from
+    # its non-bang version in that it passes through the attribute setter.
+    # Saving is not subjected to validation checks. Returns +true+ if the
+    # record could be saved.
+    def increment!(attribute, by = 1)
+      increment(attribute, by).update_attribute(attribute, self[attribute])
+    end
+
+    # Initializes +attribute+ to zero if +nil+ and subtracts the value passed as +by+ (default is 1).
+    # The decrement is performed directly on the underlying attribute, no setter is invoked.
+    # Only makes sense for number-based attributes. Returns +self+.
+    def decrement(attribute, by = 1)
+      self[attribute] ||= 0
+      self[attribute] -= by
+      self
+    end
+
+    # Wrapper around +decrement+ that saves the record. This method differs from
+    # its non-bang version in that it passes through the attribute setter.
+    # Saving is not subjected to validation checks. Returns +true+ if the
+    # record could be saved.
+    def decrement!(attribute, by = 1)
+      decrement(attribute, by).update_attribute(attribute, self[attribute])
+    end
+
+    # Assigns to +attribute+ the boolean opposite of <tt>attribute?</tt>. So
+    # if the predicate returns +true+ the attribute will become +false+. This
+    # method toggles directly the underlying value without calling any setter.
+    # Returns +self+.
+    def toggle(attribute)
+      self[attribute] = !send("#{attribute}?")
+      self
+    end
+
+    # Wrapper around +toggle+ that saves the record. This method differs from
+    # its non-bang version in that it passes through the attribute setter.
+    # Saving is not subjected to validation checks. Returns +true+ if the
+    # record could be saved.
+    def toggle!(attribute)
+      toggle(attribute).update_attribute(attribute, self[attribute])
+    end
+
+    # Reloads the record from the database.
+    #
+    # This method finds record by its primary key (which could be assigned manually) and
+    # modifies the receiver in-place:
+    #
+    #   account = Account.new
+    #   # => #<Account id: nil, email: nil>
+    #   account.id = 1
+    #   account.reload
+    #   # Account Load (1.2ms)  SELECT "accounts".* FROM "accounts" WHERE "accounts"."id" = $1 LIMIT 1  [["id", 1]]
+    #   # => #<Account id: 1, email: 'account@example.com'>
+    #
+    # Attributes are reloaded from the database, and caches busted, in
+    # particular the associations cache.
+    #
+    # If the record no longer exists in the database <tt>ActiveRecord::RecordNotFound</tt>
+    # is raised. Otherwise, in addition to the in-place modification the method
+    # returns +self+ for convenience.
+    #
+    # The optional <tt>:lock</tt> flag option allows you to lock the reloaded record:
+    #
+    #   reload(lock: true) # reload with pessimistic locking
+    #
+    # Reloading is commonly used in test suites to test something is actually
+    # written to the database, or when some action modifies the corresponding
+    # row in the database but not the object in memory:
+    #
+    #   assert account.deposit!(25)
+    #   assert_equal 25, account.credit        # check it is updated in memory
+    #   assert_equal 25, account.reload.credit # check it is also persisted
+    #
+    # Another common use case is optimistic locking handling:
+    #
+    #   def with_optimistic_retry
+    #     begin
+    #       yield
+    #     rescue ActiveRecord::StaleObjectError
+    #       begin
+    #         # Reload lock_version in particular.
+    #         reload
+    #       rescue ActiveRecord::RecordNotFound
+    #         # If the record is gone there is nothing to do.
+    #       else
+    #         retry
+    #       end
+    #     end
+    #   end
+    #
+    def reload(options = nil)
+      clear_aggregation_cache
+      clear_association_cache
+
+      fresh_object =
+        if options && options[:lock]
+          self.class.unscoped { self.class.lock(options[:lock]).find(id) }
+        else
+          self.class.unscoped { self.class.find(id) }
+        end
+
+      @attributes = fresh_object.instance_variable_get('@attributes')
+      @new_record = false
+      self
+    end
+
+    # Saves the record with the updated_at/on attributes set to the current time.
+    # Please note that no validation is performed and only the +after_touch+,
+    # +after_commit+ and +after_rollback+ callbacks are executed.
+    #
+    # If attribute names are passed, they are updated along with updated_at/on
+    # attributes.
+    #
+    #   product.touch                         # updates updated_at/on
+    #   product.touch(:designed_at)           # updates the designed_at attribute and updated_at/on
+    #   product.touch(:started_at, :ended_at) # updates started_at, ended_at and updated_at/on attributes
+    #
+    # If used along with +belongs_to+ then +touch+ will invoke +touch+ method on
+    # associated object.
+    #
+    #   class Brake < ActiveRecord::Base
+    #     belongs_to :car, touch: true
+    #   end
+    #
+    #   class Car < ActiveRecord::Base
+    #     belongs_to :corporation, touch: true
+    #   end
+    #
+    #   # triggers @brake.car.touch and @brake.car.corporation.touch
+    #   @brake.touch
+    #
+    # Note that +touch+ must be used on a persisted object, or else an
+    # ActiveRecordError will be thrown. For example:
+    #
+    #   ball = Ball.new
+    #   ball.touch(:updated_at)   # => raises ActiveRecordError
+    #
+    def touch(*names)
+      raise ActiveRecordError, "cannot touch on a new record object" unless persisted?
+
+      attributes = timestamp_attributes_for_update_in_model
+      attributes.concat(names)
+
+      unless attributes.empty?
+        current_time = current_time_from_proper_timezone
+        changes = {}
+
+        attributes.each do |column|
+          column = column.to_s
+          changes[column] = write_attribute(column, current_time)
+        end
+
+        changes[self.class.locking_column] = increment_lock if locking_enabled?
+
+        changed_attributes.except!(*changes.keys)
+        primary_key = self.class.primary_key
+        self.class.unscoped.where(primary_key => self[primary_key]).update_all(changes) == 1
+      else
+        true
+      end
+    end
+
+  private
+
+    # A hook to be overridden by association modules.
+    def destroy_associations
+    end
+
+    def destroy_row
+      relation_for_destroy.delete_all
+    end
+
+    def relation_for_destroy
+      pk         = self.class.primary_key
+      column     = self.class.columns_hash[pk]
+      substitute = self.class.connection.substitute_at(column, 0)
+
+      relation = self.class.unscoped.where(
+        self.class.arel_table[pk].eq(substitute))
+
+      relation.bind_values = [[column, id]]
+      relation
+    end
+
+    def create_or_update
+      raise ReadOnlyRecord if readonly?
+      result = new_record? ? _create_record : _update_record
+      result != false
+    end
+
+    # Updates the associated record with values matching those of the instance attributes.
+    # Returns the number of affected rows.
+    def _update_record(attribute_names = self.attribute_names)
+      attributes_values = arel_attributes_with_values_for_update(attribute_names)
+      if attributes_values.empty?
+        0
+      else
+        self.class.unscoped._update_record attributes_values, id, id_was
+      end
+    end
+
+    # Creates a record with values matching those of the instance attributes
+    # and returns its id.
+    def _create_record(attribute_names = self.attribute_names)
+      attributes_values = arel_attributes_with_values_for_create(attribute_names)
+
+      new_id = self.class.unscoped.insert attributes_values
+      self.id ||= new_id if self.class.primary_key
+
+      @new_record = false
+      id
+    end
+
+    def verify_readonly_attribute(name)
+      raise ActiveRecordError, "#{name} is marked as readonly" if self.class.readonly_attributes.include?(name)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/query_cache.rb b/activerecord/lib/active_record/query_cache.rb
new file mode 100644
index 0000000000..dcb2bd3d84
--- /dev/null
+++ b/activerecord/lib/active_record/query_cache.rb
@@ -0,0 +1,56 @@
+module ActiveRecord
+  # = Active Record Query Cache
+  class QueryCache
+    module ClassMethods
+      # Enable the query cache within the block if Active Record is configured.
+      # If it's not, it will execute the given block.
+      def cache(&block)
+        if ActiveRecord::Base.connected?
+          connection.cache(&block)
+        else
+          yield
+        end
+      end
+
+      # Disable the query cache within the block if Active Record is configured.
+      # If it's not, it will execute the given block.
+      def uncached(&block)
+        if ActiveRecord::Base.connected?
+          connection.uncached(&block)
+        else
+          yield
+        end
+      end
+    end
+
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      connection    = ActiveRecord::Base.connection
+      enabled       = connection.query_cache_enabled
+      connection_id = ActiveRecord::Base.connection_id
+      connection.enable_query_cache!
+
+      response = @app.call(env)
+      response[2] = Rack::BodyProxy.new(response[2]) do
+        restore_query_cache_settings(connection_id, enabled)
+      end
+
+      response
+    rescue Exception => e
+      restore_query_cache_settings(connection_id, enabled)
+      raise e
+    end
+
+    private
+
+    def restore_query_cache_settings(connection_id, enabled)
+      ActiveRecord::Base.connection_id = connection_id
+      ActiveRecord::Base.connection.clear_query_cache
+      ActiveRecord::Base.connection.disable_query_cache! unless enabled
+    end
+
+  end
+end
diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb
new file mode 100644
index 0000000000..a9ddd9141f
--- /dev/null
+++ b/activerecord/lib/active_record/querying.rb
@@ -0,0 +1,58 @@
+module ActiveRecord
+  module Querying
+    delegate :find, :take, :take!, :first, :first!, :last, :last!, :exists?, :any?, :many?, to: :all
+    delegate :second, :second!, :third, :third!, :fourth, :fourth!, :fifth, :fifth!, :forty_two, :forty_two!, to: :all
+    delegate :first_or_create, :first_or_create!, :first_or_initialize, to: :all
+    delegate :find_or_create_by, :find_or_create_by!, :find_or_initialize_by, to: :all
+    delegate :find_by, :find_by!, to: :all
+    delegate :destroy, :destroy_all, :delete, :delete_all, :update, :update_all, to: :all
+    delegate :find_each, :find_in_batches, to: :all
+    delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins,
+             :where, :rewhere, :preload, :eager_load, :includes, :from, :lock, :readonly,
+             :having, :create_with, :uniq, :distinct, :references, :none, :unscope, to: :all
+    delegate :count, :average, :minimum, :maximum, :sum, :calculate, to: :all
+    delegate :pluck, :ids, to: :all
+
+    # Executes a custom SQL query against your database and returns all the results. The results will
+    # be returned as an array with columns requested encapsulated as attributes of the model you call
+    # this method from. If you call <tt>Product.find_by_sql</tt> then the results will be returned in
+    # a +Product+ object with the attributes you specified in the SQL query.
+    #
+    # If you call a complicated SQL query which spans multiple tables the columns specified by the
+    # SELECT will be attributes of the model, whether or not they are columns of the corresponding
+    # table.
+    #
+    # The +sql+ parameter is a full SQL query as a string. It will be called as is, there will be
+    # no database agnostic conversions performed. This should be a last resort because using, for example,
+    # MySQL specific terms will lock you to using that particular database engine or require you to
+    # change your call if you switch engines.
+    #
+    #   # A simple SQL query spanning multiple tables
+    #   Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id"
+    #   # => [#<Post:0x36bff9c @attributes={"title"=>"Ruby Meetup", "first_name"=>"Quentin"}>, ...]
+    #
+    # You can use the same string replacement techniques as you can with <tt>ActiveRecord::QueryMethods#where</tt>:
+    #
+    #   Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date]
+    #   Post.find_by_sql ["SELECT body FROM comments WHERE author = :user_id OR approved_by = :user_id", { :user_id => user_id }]
+    def find_by_sql(sql, binds = [])
+      result_set = connection.select_all(sanitize_sql(sql), "#{name} Load", binds)
+      column_types = result_set.column_types.except(*columns_hash.keys)
+      result_set.map { |record| instantiate(record, column_types) }
+    end
+
+    # Returns the result of an SQL statement that should only include a COUNT(*) in the SELECT part.
+    # The use of this method should be restricted to complicated SQL queries that can't be executed
+    # using the ActiveRecord::Calculations class methods. Look into those before using this.
+    #
+    # ==== Parameters
+    #
+    # * +sql+ - An SQL statement which should return a count query from the database, see the example below.
+    #
+    #   Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"
+    def count_by_sql(sql)
+      sql = sanitize_conditions(sql)
+      connection.select_value(sql, "#{name} Count").to_i
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
new file mode 100644
index 0000000000..a4ceacbf44
--- /dev/null
+++ b/activerecord/lib/active_record/railtie.rb
@@ -0,0 +1,164 @@
+require "active_record"
+require "rails"
+require "active_model/railtie"
+
+# For now, action_controller must always be present with
+# rails, so let's make sure that it gets required before
+# here. This is needed for correctly setting up the middleware.
+# In the future, this might become an optional require.
+require "action_controller/railtie"
+
+module ActiveRecord
+  # = Active Record Railtie
+  class Railtie < Rails::Railtie # :nodoc:
+    config.active_record = ActiveSupport::OrderedOptions.new
+
+    config.app_generators.orm :active_record, :migration => true,
+                                              :timestamps => true
+
+    config.app_middleware.insert_after "::ActionDispatch::Callbacks",
+      "ActiveRecord::QueryCache"
+
+    config.app_middleware.insert_after "::ActionDispatch::Callbacks",
+      "ActiveRecord::ConnectionAdapters::ConnectionManagement"
+
+    config.action_dispatch.rescue_responses.merge!(
+      'ActiveRecord::RecordNotFound'   => :not_found,
+      'ActiveRecord::StaleObjectError' => :conflict,
+      'ActiveRecord::RecordInvalid'    => :unprocessable_entity,
+      'ActiveRecord::RecordNotSaved'   => :unprocessable_entity
+    )
+
+
+    config.active_record.use_schema_cache_dump = true
+    config.active_record.maintain_test_schema = true
+
+    config.eager_load_namespaces << ActiveRecord
+
+    rake_tasks do
+      require "active_record/base"
+
+      namespace :db do
+        task :load_config do
+          ActiveRecord::Tasks::DatabaseTasks.database_configuration = Rails.application.config.database_configuration
+
+          if defined?(ENGINE_PATH) && engine = Rails::Engine.find(ENGINE_PATH)
+            if engine.paths['db/migrate'].existent
+              ActiveRecord::Tasks::DatabaseTasks.migrations_paths += engine.paths['db/migrate'].to_a
+            end
+          end
+        end
+      end
+
+      load "active_record/railties/databases.rake"
+    end
+
+    # When loading console, force ActiveRecord::Base to be loaded
+    # to avoid cross references when loading a constant for the
+    # first time. Also, make it output to STDERR.
+    console do |app|
+      require "active_record/railties/console_sandbox" if app.sandbox?
+      require "active_record/base"
+      console = ActiveSupport::Logger.new(STDERR)
+      Rails.logger.extend ActiveSupport::Logger.broadcast console
+    end
+
+    runner do
+      require "active_record/base"
+    end
+
+    initializer "active_record.initialize_timezone" do
+      ActiveSupport.on_load(:active_record) do
+        self.time_zone_aware_attributes = true
+        self.default_timezone = :utc
+      end
+    end
+
+    initializer "active_record.logger" do
+      ActiveSupport.on_load(:active_record) { self.logger ||= ::Rails.logger }
+    end
+
+    initializer "active_record.migration_error" do
+      if config.active_record.delete(:migration_error) == :page_load
+        config.app_middleware.insert_after "::ActionDispatch::Callbacks",
+          "ActiveRecord::Migration::CheckPending"
+      end
+    end
+
+    initializer "active_record.check_schema_cache_dump" do
+      if config.active_record.delete(:use_schema_cache_dump)
+        config.after_initialize do |app|
+          ActiveSupport.on_load(:active_record) do
+            filename = File.join(app.config.paths["db"].first, "schema_cache.dump")
+
+            if File.file?(filename)
+              cache = Marshal.load File.binread filename
+              if cache.version == ActiveRecord::Migrator.current_version
+                self.connection.schema_cache = cache
+              else
+                warn "Ignoring db/schema_cache.dump because it has expired. The current schema version is #{ActiveRecord::Migrator.current_version}, but the one in the cache is #{cache.version}."
+              end
+            end
+          end
+        end
+      end
+    end
+
+    initializer "active_record.set_configs" do |app|
+      ActiveSupport.on_load(:active_record) do
+        app.config.active_record.each do |k,v|
+          send "#{k}=", v
+        end
+      end
+    end
+
+    # This sets the database configuration from Configuration#database_configuration
+    # and then establishes the connection.
+    initializer "active_record.initialize_database" do |app|
+      ActiveSupport.on_load(:active_record) do
+        self.configurations = Rails.application.config.database_configuration
+
+        begin
+          establish_connection
+        rescue ActiveRecord::NoDatabaseError
+          warn <<-end_warning
+Oops - You have a database configured, but it doesn't exist yet!
+
+Here's how to get started:
+
+  1. Configure your database in config/database.yml.
+  2. Run `bin/rake db:create` to create the database.
+  3. Run `bin/rake db:setup` to load your database schema.
+end_warning
+          raise
+        end
+      end
+    end
+
+    # Expose database runtime to controller for logging.
+    initializer "active_record.log_runtime" do
+      require "active_record/railties/controller_runtime"
+      ActiveSupport.on_load(:action_controller) do
+        include ActiveRecord::Railties::ControllerRuntime
+      end
+    end
+
+    initializer "active_record.set_reloader_hooks" do |app|
+      hook = app.config.reload_classes_only_on_change ? :to_prepare : :to_cleanup
+
+      ActiveSupport.on_load(:active_record) do
+        ActionDispatch::Reloader.send(hook) do
+          if ActiveRecord::Base.connected?
+            ActiveRecord::Base.clear_reloadable_connections!
+            ActiveRecord::Base.clear_cache!
+          end
+        end
+      end
+    end
+
+    initializer "active_record.add_watchable_files" do |app|
+      path = app.paths["db"].first
+      config.watchable_files.concat ["#{path}/schema.rb", "#{path}/structure.sql"]
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railties/console_sandbox.rb b/activerecord/lib/active_record/railties/console_sandbox.rb
new file mode 100644
index 0000000000..604a220303
--- /dev/null
+++ b/activerecord/lib/active_record/railties/console_sandbox.rb
@@ -0,0 +1,5 @@
+ActiveRecord::Base.connection.begin_transaction(joinable: false)
+
+at_exit do
+  ActiveRecord::Base.connection.rollback_transaction
+end
diff --git a/activerecord/lib/active_record/railties/controller_runtime.rb b/activerecord/lib/active_record/railties/controller_runtime.rb
new file mode 100644
index 0000000000..af4840476c
--- /dev/null
+++ b/activerecord/lib/active_record/railties/controller_runtime.rb
@@ -0,0 +1,50 @@
+require 'active_support/core_ext/module/attr_internal'
+require 'active_record/log_subscriber'
+
+module ActiveRecord
+  module Railties # :nodoc:
+    module ControllerRuntime #:nodoc:
+      extend ActiveSupport::Concern
+
+    protected
+
+      attr_internal :db_runtime
+
+      def process_action(action, *args)
+        # We also need to reset the runtime before each action
+        # because of queries in middleware or in cases we are streaming
+        # and it won't be cleaned up by the method below.
+        ActiveRecord::LogSubscriber.reset_runtime
+        super
+      end
+
+      def cleanup_view_runtime
+        if ActiveRecord::Base.connected?
+          db_rt_before_render = ActiveRecord::LogSubscriber.reset_runtime
+          self.db_runtime = (db_runtime || 0) + db_rt_before_render
+          runtime = super
+          db_rt_after_render = ActiveRecord::LogSubscriber.reset_runtime
+          self.db_runtime += db_rt_after_render
+          runtime - db_rt_after_render
+        else
+          super
+        end
+      end
+
+      def append_info_to_payload(payload)
+        super
+        if ActiveRecord::Base.connected?
+          payload[:db_runtime] = (db_runtime || 0) + ActiveRecord::LogSubscriber.reset_runtime
+        end
+      end
+
+      module ClassMethods # :nodoc:
+        def log_process_action(payload)
+          messages, db_runtime = super, payload[:db_runtime]
+          messages << ("ActiveRecord: %.1fms" % db_runtime.to_f) if db_runtime
+          messages
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
new file mode 100644
index 0000000000..458862a538
--- /dev/null
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -0,0 +1,390 @@
+require 'active_record'
+
+db_namespace = namespace :db do
+  task :load_config do
+    ActiveRecord::Base.configurations       = ActiveRecord::Tasks::DatabaseTasks.database_configuration || {}
+    ActiveRecord::Migrator.migrations_paths = ActiveRecord::Tasks::DatabaseTasks.migrations_paths
+  end
+
+  namespace :create do
+    task :all => :load_config do
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+  end
+
+  desc 'Creates the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:create:all to create all databases in the config). Without RAILS_ENV it defaults to creating the development and test databases.'
+  task :create => [:load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.create_current
+  end
+
+  namespace :drop do
+    task :all => :load_config do
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+  end
+
+  desc 'Drops the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:drop:all to drop all databases in the config). Without RAILS_ENV it defaults to dropping the development and test databases.'
+  task :drop => [:load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.drop_current
+  end
+
+  namespace :purge do
+    task :all => :load_config do
+      ActiveRecord::Tasks::DatabaseTasks.purge_all
+    end
+  end
+
+  # desc "Empty the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:drop:all to drop all databases in the config). Without RAILS_ENV it defaults to purging the development and test databases."
+  task :purge => [:load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.purge_current
+  end
+
+  desc "Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)."
+  task :migrate => [:environment, :load_config] do
+    ActiveRecord::Tasks::DatabaseTasks.migrate
+    db_namespace['_dump'].invoke if ActiveRecord::Base.dump_schema_after_migration
+  end
+
+  task :_dump do
+    case ActiveRecord::Base.schema_format
+    when :ruby then db_namespace["schema:dump"].invoke
+    when :sql  then db_namespace["structure:dump"].invoke
+    else
+      raise "unknown schema format #{ActiveRecord::Base.schema_format}"
+    end
+    # Allow this task to be called as many times as required. An example is the
+    # migrate:redo task, which calls other two internally that depend on this one.
+    db_namespace['_dump'].reenable
+  end
+
+  namespace :migrate do
+    # desc  'Rollbacks the database one migration and re migrate up (options: STEP=x, VERSION=x).'
+    task :redo => [:environment, :load_config] do
+      if ENV['VERSION']
+        db_namespace['migrate:down'].invoke
+        db_namespace['migrate:up'].invoke
+      else
+        db_namespace['rollback'].invoke
+        db_namespace['migrate'].invoke
+      end
+    end
+
+    # desc 'Resets your database using your migrations for the current environment'
+    task :reset => ['db:drop', 'db:create', 'db:migrate']
+
+    # desc 'Runs the "up" for a given migration VERSION.'
+    task :up => [:environment, :load_config] do
+      version = ENV['VERSION'] ? ENV['VERSION'].to_i : nil
+      raise 'VERSION is required' unless version
+      ActiveRecord::Migrator.run(:up, ActiveRecord::Migrator.migrations_paths, version)
+      db_namespace['_dump'].invoke
+    end
+
+    # desc 'Runs the "down" for a given migration VERSION.'
+    task :down => [:environment, :load_config] do
+      version = ENV['VERSION'] ? ENV['VERSION'].to_i : nil
+      raise 'VERSION is required - To go down one migration, run db:rollback' unless version
+      ActiveRecord::Migrator.run(:down, ActiveRecord::Migrator.migrations_paths, version)
+      db_namespace['_dump'].invoke
+    end
+
+    desc 'Display status of migrations'
+    task :status => [:environment, :load_config] do
+      unless ActiveRecord::SchemaMigration.table_exists?
+        abort 'Schema migrations table does not exist yet.'
+      end
+      db_list = ActiveRecord::SchemaMigration.normalized_versions
+
+      file_list =
+          ActiveRecord::Migrator.migrations_paths.flat_map do |path|
+            # match "20091231235959_some_name.rb" and "001_some_name.rb" pattern
+            Dir.foreach(path).grep(/^(\d{3,})_(.+)\.rb$/) do
+              version = ActiveRecord::SchemaMigration.normalize_migration_number($1)
+              status = db_list.delete(version) ? 'up' : 'down'
+              [status, version, $2.humanize]
+            end
+          end
+
+      db_list.map! do |version|
+        ['up', version, '********** NO FILE **********']
+      end
+      # output
+      puts "\ndatabase: #{ActiveRecord::Base.connection_config[:database]}\n\n"
+      puts "#{'Status'.center(8)}  #{'Migration ID'.ljust(14)}  Migration Name"
+      puts "-" * 50
+      (db_list + file_list).sort_by { |_, version, _| version }.each do |status, version, name|
+        puts "#{status.center(8)}  #{version.ljust(14)}  #{name}"
+      end
+      puts
+    end
+  end
+
+  desc 'Rolls the schema back to the previous version (specify steps w/ STEP=n).'
+  task :rollback => [:environment, :load_config] do
+    step = ENV['STEP'] ? ENV['STEP'].to_i : 1
+    ActiveRecord::Migrator.rollback(ActiveRecord::Migrator.migrations_paths, step)
+    db_namespace['_dump'].invoke
+  end
+
+  # desc 'Pushes the schema to the next version (specify steps w/ STEP=n).'
+  task :forward => [:environment, :load_config] do
+    step = ENV['STEP'] ? ENV['STEP'].to_i : 1
+    ActiveRecord::Migrator.forward(ActiveRecord::Migrator.migrations_paths, step)
+    db_namespace['_dump'].invoke
+  end
+
+  # desc 'Drops and recreates the database from db/schema.rb for the current environment and loads the seeds.'
+  task :reset => [:environment, :load_config] do
+    db_namespace["drop"].invoke
+    db_namespace["setup"].invoke
+  end
+
+  # desc "Retrieves the charset for the current environment's database"
+  task :charset => [:environment, :load_config] do
+    puts ActiveRecord::Tasks::DatabaseTasks.charset_current
+  end
+
+  # desc "Retrieves the collation for the current environment's database"
+  task :collation => [:environment, :load_config] do
+    begin
+      puts ActiveRecord::Tasks::DatabaseTasks.collation_current
+    rescue NoMethodError
+      $stderr.puts 'Sorry, your database adapter is not supported yet. Feel free to submit a patch.'
+    end
+  end
+
+  desc 'Retrieves the current schema version number'
+  task :version => [:environment, :load_config] do
+    puts "Current version: #{ActiveRecord::Migrator.current_version}"
+  end
+
+  # desc "Raises an error if there are pending migrations"
+  task :abort_if_pending_migrations => :environment do
+    pending_migrations = ActiveRecord::Migrator.open(ActiveRecord::Migrator.migrations_paths).pending_migrations
+
+    if pending_migrations.any?
+      puts "You have #{pending_migrations.size} pending #{pending_migrations.size > 1 ? 'migrations:' : 'migration:'}"
+      pending_migrations.each do |pending_migration|
+        puts '  %4d %s' % [pending_migration.version, pending_migration.name]
+      end
+      abort %{Run `rake db:migrate` to update your database then try again.}
+    end
+  end
+
+  desc 'Create the database, load the schema, and initialize with the seed data (use db:reset to also drop the database first)'
+  task :setup => ['db:schema:load_if_ruby', 'db:structure:load_if_sql', :seed]
+
+  desc 'Load the seed data from db/seeds.rb'
+  task :seed do
+    db_namespace['abort_if_pending_migrations'].invoke
+    ActiveRecord::Tasks::DatabaseTasks.load_seed
+  end
+
+  namespace :fixtures do
+    desc "Load fixtures into the current environment's database. Load specific fixtures using FIXTURES=x,y. Load from subdirectory in test/fixtures using FIXTURES_DIR=z. Specify an alternative path (eg. spec/fixtures) using FIXTURES_PATH=spec/fixtures."
+    task :load => [:environment, :load_config] do
+      require 'active_record/fixtures'
+
+      base_dir = ActiveRecord::Tasks::DatabaseTasks.fixtures_path
+
+      fixtures_dir = if ENV['FIXTURES_DIR']
+                       File.join base_dir, ENV['FIXTURES_DIR']
+                     else
+                       base_dir
+                     end
+
+      fixture_files = if ENV['FIXTURES']
+                        ENV['FIXTURES'].split(',')
+                      else
+                        Pathname.glob("#{fixtures_dir}/**/*.yml").map {|f| f.basename.sub_ext('').to_s }
+                      end
+
+      ActiveRecord::FixtureSet.create_fixtures(fixtures_dir, fixture_files)
+    end
+
+    # desc "Search for a fixture given a LABEL or ID. Specify an alternative path (eg. spec/fixtures) using FIXTURES_PATH=spec/fixtures."
+    task :identify => [:environment, :load_config] do
+      require 'active_record/fixtures'
+
+      label, id = ENV['LABEL'], ENV['ID']
+      raise 'LABEL or ID required' if label.blank? && id.blank?
+
+      puts %Q(The fixture ID for "#{label}" is #{ActiveRecord::FixtureSet.identify(label)}.) if label
+
+      base_dir = ActiveRecord::Tasks::DatabaseTasks.fixtures_path
+
+      Dir["#{base_dir}/**/*.yml"].each do |file|
+        if data = YAML::load(ERB.new(IO.read(file)).result)
+          data.keys.each do |key|
+            key_id = ActiveRecord::FixtureSet.identify(key)
+
+            if key == label || key_id == id.to_i
+              puts "#{file}: #{key} (#{key_id})"
+            end
+          end
+        end
+      end
+    end
+  end
+
+  namespace :schema do
+    desc 'Create a db/schema.rb file that is portable against any DB supported by AR'
+    task :dump => [:environment, :load_config] do
+      require 'active_record/schema_dumper'
+      filename = ENV['SCHEMA'] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, 'schema.rb')
+      File.open(filename, "w:utf-8") do |file|
+        ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, file)
+      end
+      db_namespace['schema:dump'].reenable
+    end
+
+    desc 'Load a schema.rb file into the database'
+    task :load => [:environment, :load_config] do
+      ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:ruby, ENV['SCHEMA'])
+    end
+
+    task :load_if_ruby => ['db:create', :environment] do
+      db_namespace["schema:load"].invoke if ActiveRecord::Base.schema_format == :ruby
+    end
+
+    namespace :cache do
+      desc 'Create a db/schema_cache.dump file.'
+      task :dump => [:environment, :load_config] do
+        con = ActiveRecord::Base.connection
+        filename = File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "schema_cache.dump")
+
+        con.schema_cache.clear!
+        con.tables.each { |table| con.schema_cache.add(table) }
+        open(filename, 'wb') { |f| f.write(Marshal.dump(con.schema_cache)) }
+      end
+
+      desc 'Clear a db/schema_cache.dump file.'
+      task :clear => [:environment, :load_config] do
+        filename = File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "schema_cache.dump")
+        FileUtils.rm(filename) if File.exist?(filename)
+      end
+    end
+
+  end
+
+  namespace :structure do
+    desc 'Dump the database structure to db/structure.sql. Specify another file with DB_STRUCTURE=db/my_structure.sql'
+    task :dump => [:environment, :load_config] do
+      filename = ENV['DB_STRUCTURE'] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "structure.sql")
+      current_config = ActiveRecord::Tasks::DatabaseTasks.current_config
+      ActiveRecord::Tasks::DatabaseTasks.structure_dump(current_config, filename)
+
+      if ActiveRecord::Base.connection.supports_migrations? &&
+          ActiveRecord::SchemaMigration.table_exists?
+        File.open(filename, "a") do |f|
+          f.puts ActiveRecord::Base.connection.dump_schema_information
+          f.print "\n"
+        end
+      end
+      db_namespace['structure:dump'].reenable
+    end
+
+    desc "Recreate the databases from the structure.sql file"
+    task :load => [:environment, :load_config] do
+      ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:sql, ENV['DB_STRUCTURE'])
+    end
+
+    task :load_if_sql => ['db:create', :environment] do
+      db_namespace["structure:load"].invoke if ActiveRecord::Base.schema_format == :sql
+    end
+  end
+
+  namespace :test do
+
+    task :deprecated do
+      Rake.application.top_level_tasks.grep(/^db:test:/).each do |task|
+        $stderr.puts "WARNING: #{task} is deprecated. The Rails test helper now maintains " \
+                     "your test schema automatically, see the release notes for details."
+      end
+    end
+
+    # desc "Recreate the test database from the current schema"
+    task :load => %w(db:test:deprecated db:test:purge) do
+      case ActiveRecord::Base.schema_format
+        when :ruby
+          db_namespace["test:load_schema"].invoke
+        when :sql
+          db_namespace["test:load_structure"].invoke
+      end
+    end
+
+    # desc "Recreate the test database from an existent schema.rb file"
+    task :load_schema => %w(db:test:deprecated db:test:purge) do
+      begin
+        should_reconnect = ActiveRecord::Base.connection_pool.active_connection?
+        ActiveRecord::Schema.verbose = false
+        ActiveRecord::Tasks::DatabaseTasks.load_schema_for ActiveRecord::Base.configurations['test'], :ruby, ENV['SCHEMA']
+      ensure
+        if should_reconnect
+          ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations[ActiveRecord::Tasks::DatabaseTasks.env])
+        end
+      end
+    end
+
+    # desc "Recreate the test database from an existent structure.sql file"
+    task :load_structure => %w(db:test:deprecated db:test:purge) do
+      ActiveRecord::Tasks::DatabaseTasks.load_schema_for ActiveRecord::Base.configurations['test'], :sql, ENV['SCHEMA']
+    end
+
+    # desc "Recreate the test database from a fresh schema"
+    task :clone => %w(db:test:deprecated environment) do
+      case ActiveRecord::Base.schema_format
+        when :ruby
+          db_namespace["test:clone_schema"].invoke
+        when :sql
+          db_namespace["test:clone_structure"].invoke
+      end
+    end
+
+    # desc "Recreate the test database from a fresh schema.rb file"
+    task :clone_schema => %w(db:test:deprecated db:schema:dump db:test:load_schema)
+
+    # desc "Recreate the test database from a fresh structure.sql file"
+    task :clone_structure => %w(db:test:deprecated db:structure:dump db:test:load_structure)
+
+    # desc "Empty the test database"
+    task :purge => %w(db:test:deprecated environment load_config) do
+      ActiveRecord::Tasks::DatabaseTasks.purge ActiveRecord::Base.configurations['test']
+    end
+
+    # desc 'Check for pending migrations and load the test schema'
+    task :prepare => %w(db:test:deprecated environment load_config) do
+      unless ActiveRecord::Base.configurations.blank?
+        db_namespace['test:load'].invoke
+      end
+    end
+  end
+end
+
+namespace :railties do
+  namespace :install do
+    # desc "Copies missing migrations from Railties (e.g. engines). You can specify Railties to use with FROM=railtie1,railtie2"
+    task :migrations => :'db:load_config' do
+      to_load = ENV['FROM'].blank? ? :all : ENV['FROM'].split(",").map {|n| n.strip }
+      railties = {}
+      Rails.application.migration_railties.each do |railtie|
+        next unless to_load == :all || to_load.include?(railtie.railtie_name)
+
+        if railtie.respond_to?(:paths) && (path = railtie.paths['db/migrate'].first)
+          railties[railtie.railtie_name] = path
+        end
+      end
+
+      on_skip = Proc.new do |name, migration|
+        puts "NOTE: Migration #{migration.basename} from #{name} has been skipped. Migration with the same name already exists."
+      end
+
+      on_copy = Proc.new do |name, migration|
+        puts "Copied migration #{migration.basename} from #{name}"
+      end
+
+      ActiveRecord::Migration.copy(ActiveRecord::Migrator.migrations_paths.first, railties,
+                                    :on_skip => on_skip, :on_copy => on_copy)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railties/jdbcmysql_error.rb b/activerecord/lib/active_record/railties/jdbcmysql_error.rb
new file mode 100644
index 0000000000..6a38211bff
--- /dev/null
+++ b/activerecord/lib/active_record/railties/jdbcmysql_error.rb
@@ -0,0 +1,16 @@
+#FIXME Remove if ArJdbcMysql will give.
+module ArJdbcMySQL #:nodoc:
+  class Error < StandardError #:nodoc:
+    attr_accessor :error_number, :sql_state
+
+    def initialize msg
+      super
+      @error_number = nil
+      @sql_state    = nil
+    end
+
+    # Mysql gem compatibility
+    alias_method :errno, :error_number
+    alias_method :error, :message
+  end
+end
diff --git a/activerecord/lib/active_record/readonly_attributes.rb b/activerecord/lib/active_record/readonly_attributes.rb
new file mode 100644
index 0000000000..85bbac43e4
--- /dev/null
+++ b/activerecord/lib/active_record/readonly_attributes.rb
@@ -0,0 +1,23 @@
+module ActiveRecord
+  module ReadonlyAttributes
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_attr_readonly, instance_accessor: false
+      self._attr_readonly = []
+    end
+
+    module ClassMethods
+      # Attributes listed as readonly will be used to create a new record but update operations will
+      # ignore these fields.
+      def attr_readonly(*attributes)
+        self._attr_readonly = Set.new(attributes.map { |a| a.to_s }) + (self._attr_readonly || [])
+      end
+
+      # Returns an array of all the attributes that have been specified as readonly.
+      def readonly_attributes
+        self._attr_readonly
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
new file mode 100644
index 0000000000..1547c8e3f4
--- /dev/null
+++ b/activerecord/lib/active_record/reflection.rb
@@ -0,0 +1,867 @@
+require 'thread'
+
+module ActiveRecord
+  # = Active Record Reflection
+  module Reflection # :nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_reflections
+      class_attribute :aggregate_reflections
+      self._reflections = {}
+      self.aggregate_reflections = {}
+    end
+
+    def self.create(macro, name, scope, options, ar)
+      klass = case macro
+              when :composed_of
+                AggregateReflection
+              when :has_many
+                HasManyReflection
+              when :has_one
+                HasOneReflection
+              when :belongs_to
+                BelongsToReflection
+              else
+                raise "Unsupported Macro: #{macro}"
+              end
+
+      reflection = klass.new(name, scope, options, ar)
+      options[:through] ? ThroughReflection.new(reflection) : reflection
+    end
+
+    def self.add_reflection(ar, name, reflection)
+      ar._reflections = ar._reflections.merge(name.to_s => reflection)
+    end
+
+    def self.add_aggregate_reflection(ar, name, reflection)
+      ar.aggregate_reflections = ar.aggregate_reflections.merge(name.to_s => reflection)
+    end
+
+    # \Reflection enables interrogating Active Record classes and objects
+    # about their associations and aggregations. This information can,
+    # for example, be used in a form builder that takes an Active Record object
+    # and creates input fields for all of the attributes depending on their type
+    # and displays the associations to other objects.
+    #
+    # MacroReflection class has info for AggregateReflection and AssociationReflection
+    # classes.
+    module ClassMethods
+      # Returns an array of AggregateReflection objects for all the aggregations in the class.
+      def reflect_on_all_aggregations
+        aggregate_reflections.values
+      end
+
+      # Returns the AggregateReflection object for the named +aggregation+ (use the symbol).
+      #
+      #   Account.reflect_on_aggregation(:balance) # => the balance AggregateReflection
+      #
+      def reflect_on_aggregation(aggregation)
+        aggregate_reflections[aggregation.to_s]
+      end
+
+      # Returns a Hash of name of the reflection as the key and a AssociationReflection as the value.
+      #
+      #   Account.reflections # => {balance: AggregateReflection}
+      #
+      # @api public
+      def reflections
+        ref = {}
+        _reflections.each do |name, reflection|
+          parent_name, parent_reflection = reflection.parent_reflection
+          if parent_name
+            ref[parent_name] = parent_reflection
+          else
+            ref[name] = reflection
+          end
+        end
+        ref
+      end
+
+      # Returns an array of AssociationReflection objects for all the
+      # associations in the class. If you only want to reflect on a certain
+      # association type, pass in the symbol (<tt>:has_many</tt>, <tt>:has_one</tt>,
+      # <tt>:belongs_to</tt>) as the first parameter.
+      #
+      # Example:
+      #
+      #   Account.reflect_on_all_associations             # returns an array of all associations
+      #   Account.reflect_on_all_associations(:has_many)  # returns an array of all has_many associations
+      #
+      #   @api public
+      def reflect_on_all_associations(macro = nil)
+        association_reflections = reflections.values
+        macro ? association_reflections.select { |reflection| reflection.macro == macro } : association_reflections
+      end
+
+      # Returns the AssociationReflection object for the +association+ (use the symbol).
+      #
+      #   Account.reflect_on_association(:owner)             # returns the owner AssociationReflection
+      #   Invoice.reflect_on_association(:line_items).macro  # returns :has_many
+      #
+      #   @api public
+      def reflect_on_association(association)
+        reflections[association.to_s]
+      end
+
+      #   @api private
+      def _reflect_on_association(association) #:nodoc:
+        _reflections[association.to_s]
+      end
+
+      # Returns an array of AssociationReflection objects for all associations which have <tt>:autosave</tt> enabled.
+      #
+      #   @api public
+      def reflect_on_all_autosave_associations
+        reflections.values.select { |reflection| reflection.options[:autosave] }
+      end
+    end
+
+    # Holds all the methods that are shared between MacroReflection, AssociationReflection
+    # and ThroughReflection
+    class AbstractReflection # :nodoc:
+      def table_name
+        klass.table_name
+      end
+
+      # Returns a new, unsaved instance of the associated class. +attributes+ will
+      # be passed to the class's constructor.
+      def build_association(attributes, &block)
+        klass.new(attributes, &block)
+      end
+
+      def quoted_table_name
+        klass.quoted_table_name
+      end
+
+      def primary_key_type
+        klass.type_for_attribute(klass.primary_key)
+      end
+
+      # Returns the class name for the macro.
+      #
+      # <tt>composed_of :balance, class_name: 'Money'</tt> returns <tt>'Money'</tt>
+      # <tt>has_many :clients</tt> returns <tt>'Client'</tt>
+      def class_name
+        @class_name ||= (options[:class_name] || derive_class_name).to_s
+      end
+
+      JoinKeys = Struct.new(:key, :foreign_key) # :nodoc:
+
+      def join_keys(assoc_klass)
+        JoinKeys.new(foreign_key, active_record_primary_key)
+      end
+
+      def source_macro
+        ActiveSupport::Deprecation.warn("ActiveRecord::Base.source_macro is deprecated and " \
+          "will be removed without replacement.")
+        macro
+      end
+    end
+    # Base class for AggregateReflection and AssociationReflection. Objects of
+    # AggregateReflection and AssociationReflection are returned by the Reflection::ClassMethods.
+    #
+    #   MacroReflection
+    #     AssociationReflection
+    #       AggregateReflection
+    #       HasManyReflection
+    #       HasOneReflection
+    #       BelongsToReflection
+    #         ThroughReflection
+    class MacroReflection < AbstractReflection
+      # Returns the name of the macro.
+      #
+      # <tt>composed_of :balance, class_name: 'Money'</tt> returns <tt>:balance</tt>
+      # <tt>has_many :clients</tt> returns <tt>:clients</tt>
+      attr_reader :name
+
+      attr_reader :scope
+
+      # Returns the hash of options used for the macro.
+      #
+      # <tt>composed_of :balance, class_name: 'Money'</tt> returns <tt>{ class_name: "Money" }</tt>
+      # <tt>has_many :clients</tt> returns <tt>{}</tt>
+      attr_reader :options
+
+      attr_reader :active_record
+
+      attr_reader :plural_name # :nodoc:
+
+      def initialize(name, scope, options, active_record)
+        @name          = name
+        @scope         = scope
+        @options       = options
+        @active_record = active_record
+        @klass         = options[:class]
+        @plural_name   = active_record.pluralize_table_names ?
+                            name.to_s.pluralize : name.to_s
+      end
+
+      def autosave=(autosave)
+        @automatic_inverse_of = false
+        @options[:autosave] = autosave
+        _, parent_reflection = self.parent_reflection
+        if parent_reflection
+          parent_reflection.autosave = autosave
+        end
+      end
+
+      # Returns the class for the macro.
+      #
+      # <tt>composed_of :balance, class_name: 'Money'</tt> returns the Money class
+      # <tt>has_many :clients</tt> returns the Client class
+      def klass
+        @klass ||= compute_class(class_name)
+      end
+
+      def compute_class(name)
+        name.constantize
+      end
+
+      # Returns +true+ if +self+ and +other_aggregation+ have the same +name+ attribute, +active_record+ attribute,
+      # and +other_aggregation+ has an options hash assigned to it.
+      def ==(other_aggregation)
+        super ||
+          other_aggregation.kind_of?(self.class) &&
+          name == other_aggregation.name &&
+          !other_aggregation.options.nil? &&
+          active_record == other_aggregation.active_record
+      end
+
+      private
+        def derive_class_name
+          name.to_s.camelize
+        end
+    end
+
+
+    # Holds all the meta-data about an aggregation as it was specified in the
+    # Active Record class.
+    class AggregateReflection < MacroReflection #:nodoc:
+      def mapping
+        mapping = options[:mapping] || [name, name]
+        mapping.first.is_a?(Array) ? mapping : [mapping]
+      end
+    end
+
+    # Holds all the meta-data about an association as it was specified in the
+    # Active Record class.
+    class AssociationReflection < MacroReflection #:nodoc:
+      # Returns the target association's class.
+      #
+      #   class Author < ActiveRecord::Base
+      #     has_many :books
+      #   end
+      #
+      #   Author.reflect_on_association(:books).klass
+      #   # => Book
+      #
+      # <b>Note:</b> Do not call +klass.new+ or +klass.create+ to instantiate
+      # a new association object. Use +build_association+ or +create_association+
+      # instead. This allows plugins to hook into association object creation.
+      def klass
+        @klass ||= compute_class(class_name)
+      end
+
+      def compute_class(name)
+        active_record.send(:compute_type, name)
+      end
+
+      attr_reader :type, :foreign_type
+      attr_accessor :parent_reflection # [:name, Reflection]
+
+      def initialize(name, scope, options, active_record)
+        super
+        @automatic_inverse_of = nil
+        @type         = options[:as] && "#{options[:as]}_type"
+        @foreign_type = options[:foreign_type] || "#{name}_type"
+        @constructable = calculate_constructable(macro, options)
+        @association_scope_cache = {}
+        @scope_lock = Mutex.new
+      end
+
+      def association_scope_cache(conn, owner)
+        key = conn.prepared_statements
+        if polymorphic?
+          key = [key, owner.read_attribute(@foreign_type)]
+        end
+        @association_scope_cache[key] ||= @scope_lock.synchronize {
+          @association_scope_cache[key] ||= yield
+        }
+      end
+
+      def constructable? # :nodoc:
+        @constructable
+      end
+
+      def join_table
+        @join_table ||= options[:join_table] || derive_join_table
+      end
+
+      def foreign_key
+        @foreign_key ||= options[:foreign_key] || derive_foreign_key
+      end
+
+      def association_foreign_key
+        @association_foreign_key ||= options[:association_foreign_key] || class_name.foreign_key
+      end
+
+      # klass option is necessary to support loading polymorphic associations
+      def association_primary_key(klass = nil)
+        options[:primary_key] || primary_key(klass || self.klass)
+      end
+
+      def active_record_primary_key
+        @active_record_primary_key ||= options[:primary_key] || primary_key(active_record)
+      end
+
+      def counter_cache_column
+        if options[:counter_cache] == true
+          "#{active_record.name.demodulize.underscore.pluralize}_count"
+        elsif options[:counter_cache]
+          options[:counter_cache].to_s
+        end
+      end
+
+      def check_validity!
+        check_validity_of_inverse!
+      end
+
+      def check_validity_of_inverse!
+        unless polymorphic?
+          if has_inverse? && inverse_of.nil?
+            raise InverseOfAssociationNotFoundError.new(self)
+          end
+        end
+      end
+
+      def check_preloadable!
+        return unless scope
+
+        if scope.arity > 0
+          ActiveSupport::Deprecation.warn <<-WARNING
+The association scope '#{name}' is instance dependent (the scope block takes an argument).
+Preloading happens before the individual instances are created. This means that there is no instance
+being passed to the association scope. This will most likely result in broken or incorrect behavior.
+Joining, Preloading and eager loading of these associations is deprecated and will be removed in the future.
+          WARNING
+        end
+      end
+      alias :check_eager_loadable! :check_preloadable!
+
+      def join_id_for(owner) # :nodoc:
+        owner[active_record_primary_key]
+      end
+
+      def through_reflection
+        nil
+      end
+
+      def source_reflection
+        self
+      end
+
+      # A chain of reflections from this one back to the owner. For more see the explanation in
+      # ThroughReflection.
+      def chain
+        [self]
+      end
+
+      def nested?
+        false
+      end
+
+      # An array of arrays of scopes. Each item in the outside array corresponds to a reflection
+      # in the #chain.
+      def scope_chain
+        scope ? [[scope]] : [[]]
+      end
+
+      def has_inverse?
+        inverse_name
+      end
+
+      def inverse_of
+        return unless inverse_name
+
+        @inverse_of ||= klass._reflect_on_association inverse_name
+      end
+
+      def polymorphic_inverse_of(associated_class)
+        if has_inverse?
+          if inverse_relationship = associated_class._reflect_on_association(options[:inverse_of])
+            inverse_relationship
+          else
+            raise InverseOfAssociationNotFoundError.new(self, associated_class)
+          end
+        end
+      end
+
+      # Returns the macro type.
+      #
+      # <tt>has_many :clients</tt> returns <tt>:has_many</tt>
+      def macro; raise NotImplementedError; end
+
+      # Returns whether or not this association reflection is for a collection
+      # association. Returns +true+ if the +macro+ is either +has_many+ or
+      # +has_and_belongs_to_many+, +false+ otherwise.
+      def collection?
+        false
+      end
+
+      # Returns whether or not the association should be validated as part of
+      # the parent's validation.
+      #
+      # Unless you explicitly disable validation with
+      # <tt>validate: false</tt>, validation will take place when:
+      #
+      # * you explicitly enable validation; <tt>validate: true</tt>
+      # * you use autosave; <tt>autosave: true</tt>
+      # * the association is a +has_many+ association
+      def validate?
+        !options[:validate].nil? ? options[:validate] : (options[:autosave] == true || collection?)
+      end
+
+      # Returns +true+ if +self+ is a +belongs_to+ reflection.
+      def belongs_to?; false; end
+
+      # Returns +true+ if +self+ is a +has_one+ reflection.
+      def has_one?; false; end
+
+      def association_class
+        case macro
+        when :belongs_to
+          if polymorphic?
+            Associations::BelongsToPolymorphicAssociation
+          else
+            Associations::BelongsToAssociation
+          end
+        when :has_many
+          if options[:through]
+            Associations::HasManyThroughAssociation
+          else
+            Associations::HasManyAssociation
+          end
+        when :has_one
+          if options[:through]
+            Associations::HasOneThroughAssociation
+          else
+            Associations::HasOneAssociation
+          end
+        end
+      end
+
+      def polymorphic?
+        options[:polymorphic]
+      end
+
+      VALID_AUTOMATIC_INVERSE_MACROS = [:has_many, :has_one, :belongs_to]
+      INVALID_AUTOMATIC_INVERSE_OPTIONS = [:conditions, :through, :polymorphic, :foreign_key]
+
+      protected
+
+        def actual_source_reflection # FIXME: this is a horrible name
+          self
+        end
+
+      private
+
+        def calculate_constructable(macro, options)
+          case macro
+          when :belongs_to
+            !polymorphic?
+          when :has_one
+            !options[:through]
+          else
+            true
+          end
+        end
+
+        # Attempts to find the inverse association name automatically.
+        # If it cannot find a suitable inverse association name, it returns
+        # nil.
+        def inverse_name
+          options.fetch(:inverse_of) do
+            if @automatic_inverse_of == false
+              nil
+            else
+              @automatic_inverse_of ||= automatic_inverse_of
+            end
+          end
+        end
+
+        # returns either nil or the inverse association name that it finds.
+        def automatic_inverse_of
+          if can_find_inverse_of_automatically?(self)
+            inverse_name = ActiveSupport::Inflector.underscore(options[:as] || active_record.name).to_sym
+
+            begin
+              reflection = klass._reflect_on_association(inverse_name)
+            rescue NameError
+              # Give up: we couldn't compute the klass type so we won't be able
+              # to find any associations either.
+              reflection = false
+            end
+
+            if valid_inverse_reflection?(reflection)
+              return inverse_name
+            end
+          end
+
+          false
+        end
+
+        # Checks if the inverse reflection that is returned from the
+        # +automatic_inverse_of+ method is a valid reflection. We must
+        # make sure that the reflection's active_record name matches up
+        # with the current reflection's klass name.
+        #
+        # Note: klass will always be valid because when there's a NameError
+        # from calling +klass+, +reflection+ will already be set to false.
+        def valid_inverse_reflection?(reflection)
+          reflection &&
+            klass.name == reflection.active_record.name &&
+            can_find_inverse_of_automatically?(reflection)
+        end
+
+        # Checks to see if the reflection doesn't have any options that prevent
+        # us from being able to guess the inverse automatically. First, the
+        # <tt>inverse_of</tt> option cannot be set to false. Second, we must
+        # have <tt>has_many</tt>, <tt>has_one</tt>, <tt>belongs_to</tt> associations.
+        # Third, we must not have options such as <tt>:polymorphic</tt> or
+        # <tt>:foreign_key</tt> which prevent us from correctly guessing the
+        # inverse association.
+        #
+        # Anything with a scope can additionally ruin our attempt at finding an
+        # inverse, so we exclude reflections with scopes.
+        def can_find_inverse_of_automatically?(reflection)
+          reflection.options[:inverse_of] != false &&
+            VALID_AUTOMATIC_INVERSE_MACROS.include?(reflection.macro) &&
+            !INVALID_AUTOMATIC_INVERSE_OPTIONS.any? { |opt| reflection.options[opt] } &&
+            !reflection.scope
+        end
+
+        def derive_class_name
+          class_name = name.to_s
+          class_name = class_name.singularize if collection?
+          class_name.camelize
+        end
+
+        def derive_foreign_key
+          if belongs_to?
+            "#{name}_id"
+          elsif options[:as]
+            "#{options[:as]}_id"
+          else
+            active_record.name.foreign_key
+          end
+        end
+
+        def derive_join_table
+          ModelSchema.derive_join_table_name active_record.table_name, klass.table_name
+        end
+
+        def primary_key(klass)
+          klass.primary_key || raise(UnknownPrimaryKey.new(klass))
+        end
+    end
+
+    class HasManyReflection < AssociationReflection # :nodoc:
+      def initialize(name, scope, options, active_record)
+        super(name, scope, options, active_record)
+      end
+
+      def macro; :has_many; end
+
+      def collection?; true; end
+    end
+
+    class HasOneReflection < AssociationReflection # :nodoc:
+      def initialize(name, scope, options, active_record)
+        super(name, scope, options, active_record)
+      end
+
+      def macro; :has_one; end
+
+      def has_one?; true; end
+    end
+
+    class BelongsToReflection < AssociationReflection # :nodoc:
+      def initialize(name, scope, options, active_record)
+        super(name, scope, options, active_record)
+      end
+
+      def macro; :belongs_to; end
+
+      def belongs_to?; true; end
+
+      def join_keys(assoc_klass)
+        key = polymorphic? ? association_primary_key(assoc_klass) : association_primary_key
+        JoinKeys.new(key, foreign_key)
+      end
+
+      def join_id_for(owner) # :nodoc:
+        owner[foreign_key]
+      end
+    end
+
+    class HasAndBelongsToManyReflection < AssociationReflection # :nodoc:
+      def initialize(name, scope, options, active_record)
+        super
+      end
+
+      def macro; :has_and_belongs_to_many; end
+
+      def collection?
+        true
+      end
+    end
+
+    # Holds all the meta-data about a :through association as it was specified
+    # in the Active Record class.
+    class ThroughReflection < AbstractReflection #:nodoc:
+      attr_reader :delegate_reflection
+      delegate :foreign_key, :foreign_type, :association_foreign_key,
+               :active_record_primary_key, :type, :to => :source_reflection
+
+      def initialize(delegate_reflection)
+        @delegate_reflection = delegate_reflection
+        @klass         = delegate_reflection.options[:class]
+        @source_reflection_name = delegate_reflection.options[:source]
+      end
+
+      def klass
+        @klass ||= delegate_reflection.compute_class(class_name)
+      end
+
+      # Returns the source of the through reflection. It checks both a singularized
+      # and pluralized form for <tt>:belongs_to</tt> or <tt>:has_many</tt>.
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :taggings
+      #     has_many :tags, through: :taggings
+      #   end
+      #
+      #   class Tagging < ActiveRecord::Base
+      #     belongs_to :post
+      #     belongs_to :tag
+      #   end
+      #
+      #   tags_reflection = Post.reflect_on_association(:tags)
+      #   tags_reflection.source_reflection
+      #   # => <ActiveRecord::Reflection::BelongsToReflection: @name=:tag, @active_record=Tagging, @plural_name="tags">
+      #
+      def source_reflection
+        through_reflection.klass._reflect_on_association(source_reflection_name)
+      end
+
+      # Returns the AssociationReflection object specified in the <tt>:through</tt> option
+      # of a HasManyThrough or HasOneThrough association.
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :taggings
+      #     has_many :tags, through: :taggings
+      #   end
+      #
+      #   tags_reflection = Post.reflect_on_association(:tags)
+      #   tags_reflection.through_reflection
+      #   # => <ActiveRecord::Reflection::HasManyReflection: @name=:taggings, @active_record=Post, @plural_name="taggings">
+      #
+      def through_reflection
+        active_record._reflect_on_association(options[:through])
+      end
+
+      # Returns an array of reflections which are involved in this association. Each item in the
+      # array corresponds to a table which will be part of the query for this association.
+      #
+      # The chain is built by recursively calling #chain on the source reflection and the through
+      # reflection. The base case for the recursion is a normal association, which just returns
+      # [self] as its #chain.
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :taggings
+      #     has_many :tags, through: :taggings
+      #   end
+      #
+      #   tags_reflection = Post.reflect_on_association(:tags)
+      #   tags_reflection.chain
+      #   # => [<ActiveRecord::Reflection::ThroughReflection: @delegate_reflection=#<ActiveRecord::Reflection::HasManyReflection: @name=:tags...>,
+      #         <ActiveRecord::Reflection::HasManyReflection: @name=:taggings, @options={}, @active_record=Post>]
+      #
+      def chain
+        @chain ||= begin
+          a = source_reflection.chain
+          b = through_reflection.chain
+          chain = a + b
+          chain[0] = self # Use self so we don't lose the information from :source_type
+          chain
+        end
+      end
+
+      # Consider the following example:
+      #
+      #   class Person
+      #     has_many :articles
+      #     has_many :comment_tags, through: :articles
+      #   end
+      #
+      #   class Article
+      #     has_many :comments
+      #     has_many :comment_tags, through: :comments, source: :tags
+      #   end
+      #
+      #   class Comment
+      #     has_many :tags
+      #   end
+      #
+      # There may be scopes on Person.comment_tags, Article.comment_tags and/or Comment.tags,
+      # but only Comment.tags will be represented in the #chain. So this method creates an array
+      # of scopes corresponding to the chain.
+      def scope_chain
+        @scope_chain ||= begin
+          scope_chain = source_reflection.scope_chain.map(&:dup)
+
+          # Add to it the scope from this reflection (if any)
+          scope_chain.first << scope if scope
+
+          through_scope_chain = through_reflection.scope_chain.map(&:dup)
+
+          if options[:source_type]
+            through_scope_chain.first <<
+              through_reflection.klass.where(foreign_type => options[:source_type])
+          end
+
+          # Recursively fill out the rest of the array from the through reflection
+          scope_chain + through_scope_chain
+        end
+      end
+
+      def join_keys(assoc_klass)
+        source_reflection.join_keys(assoc_klass)
+      end
+
+      # The macro used by the source association
+      def source_macro
+        ActiveSupport::Deprecation.warn("ActiveRecord::Base.source_macro is deprecated and " \
+          "will be removed without replacement.")
+        source_reflection.source_macro
+      end
+
+      # A through association is nested if there would be more than one join table
+      def nested?
+        chain.length > 2
+      end
+
+      # We want to use the klass from this reflection, rather than just delegate straight to
+      # the source_reflection, because the source_reflection may be polymorphic. We still
+      # need to respect the source_reflection's :primary_key option, though.
+      def association_primary_key(klass = nil)
+        # Get the "actual" source reflection if the immediate source reflection has a
+        # source reflection itself
+        actual_source_reflection.options[:primary_key] || primary_key(klass || self.klass)
+      end
+
+      # Gets an array of possible <tt>:through</tt> source reflection names in both singular and plural form.
+      #
+      #   class Post < ActiveRecord::Base
+      #     has_many :taggings
+      #     has_many :tags, through: :taggings
+      #   end
+      #
+      #   tags_reflection = Post.reflect_on_association(:tags)
+      #   tags_reflection.source_reflection_names
+      #   # => [:tag, :tags]
+      #
+      def source_reflection_names
+        options[:source] ? [options[:source]] : [name.to_s.singularize, name].uniq
+      end
+
+      def source_reflection_name # :nodoc:
+        return @source_reflection_name if @source_reflection_name
+
+        names = [name.to_s.singularize, name].collect { |n| n.to_sym }.uniq
+        names = names.find_all { |n|
+          through_reflection.klass._reflect_on_association(n)
+        }
+
+        if names.length > 1
+          example_options = options.dup
+          example_options[:source] = source_reflection_names.first
+          ActiveSupport::Deprecation.warn <<-eowarn
+Ambiguous source reflection for through association.  Please specify a :source
+directive on your declaration like:
+
+  class #{active_record.name} < ActiveRecord::Base
+    #{macro} :#{name}, #{example_options}
+  end
+
+          eowarn
+        end
+
+        @source_reflection_name = names.first
+      end
+
+      def source_options
+        source_reflection.options
+      end
+
+      def through_options
+        through_reflection.options
+      end
+
+      def join_id_for(owner) # :nodoc:
+        source_reflection.join_id_for(owner)
+      end
+
+      def check_validity!
+        if through_reflection.nil?
+          raise HasManyThroughAssociationNotFoundError.new(active_record.name, self)
+        end
+
+        if through_reflection.polymorphic?
+          raise HasManyThroughAssociationPolymorphicThroughError.new(active_record.name, self)
+        end
+
+        if source_reflection.nil?
+          raise HasManyThroughSourceAssociationNotFoundError.new(self)
+        end
+
+        if options[:source_type] && !source_reflection.polymorphic?
+          raise HasManyThroughAssociationPointlessSourceTypeError.new(active_record.name, self, source_reflection)
+        end
+
+        if source_reflection.polymorphic? && options[:source_type].nil?
+          raise HasManyThroughAssociationPolymorphicSourceError.new(active_record.name, self, source_reflection)
+        end
+
+        if has_one? && through_reflection.collection?
+          raise HasOneThroughCantAssociateThroughCollection.new(active_record.name, self, through_reflection)
+        end
+
+        check_validity_of_inverse!
+      end
+
+      protected
+
+        def actual_source_reflection # FIXME: this is a horrible name
+          source_reflection.send(:actual_source_reflection)
+        end
+
+        def primary_key(klass)
+          klass.primary_key || raise(UnknownPrimaryKey.new(klass))
+        end
+
+      private
+        def derive_class_name
+          # get the class_name of the belongs_to association of the through reflection
+          options[:source_type] || source_reflection.class_name
+        end
+
+        delegate_methods = AssociationReflection.public_instance_methods -
+          public_instance_methods
+
+        delegate(*delegate_methods, to: :delegate_reflection)
+
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
new file mode 100644
index 0000000000..ad54d84665
--- /dev/null
+++ b/activerecord/lib/active_record/relation.rb
@@ -0,0 +1,674 @@
+# -*- coding: utf-8 -*-
+require 'arel/collectors/bind'
+
+module ActiveRecord
+  # = Active Record Relation
+  class Relation
+    JoinOperation = Struct.new(:relation, :join_class, :on)
+
+    MULTI_VALUE_METHODS  = [:includes, :eager_load, :preload, :select, :group,
+                            :order, :joins, :where, :having, :bind, :references,
+                            :extending, :unscope]
+
+    SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :from, :reordering,
+                            :reverse_order, :distinct, :create_with, :uniq]
+    INVALID_METHODS_FOR_DELETE_ALL = [:limit, :distinct, :offset, :group, :having]
+
+    VALUE_METHODS = MULTI_VALUE_METHODS + SINGLE_VALUE_METHODS
+
+    include FinderMethods, Calculations, SpawnMethods, QueryMethods, Batches, Explain, Delegation
+
+    attr_reader :table, :klass, :loaded
+    alias :model :klass
+    alias :loaded? :loaded
+
+    def initialize(klass, table, values = {})
+      @klass  = klass
+      @table  = table
+      @values = values
+      @offsets = {}
+      @loaded = false
+    end
+
+    def initialize_copy(other)
+      # This method is a hot spot, so for now, use Hash[] to dup the hash.
+      #   https://bugs.ruby-lang.org/issues/7166
+      @values        = Hash[@values]
+      @values[:bind] = @values[:bind].dup if @values.key? :bind
+      reset
+    end
+
+    def insert(values) # :nodoc:
+      primary_key_value = nil
+
+      if primary_key && Hash === values
+        primary_key_value = values[values.keys.find { |k|
+          k.name == primary_key
+        }]
+
+        if !primary_key_value && connection.prefetch_primary_key?(klass.table_name)
+          primary_key_value = connection.next_sequence_value(klass.sequence_name)
+          values[klass.arel_table[klass.primary_key]] = primary_key_value
+        end
+      end
+
+      im = arel.create_insert
+      im.into @table
+
+      substitutes, binds = substitute_values values
+
+      if values.empty? # empty insert
+        im.values = Arel.sql(connection.empty_insert_statement_value)
+      else
+        im.insert substitutes
+      end
+
+      @klass.connection.insert(
+        im,
+        'SQL',
+        primary_key,
+        primary_key_value,
+        nil,
+        binds)
+    end
+
+    def _update_record(values, id, id_was) # :nodoc:
+      substitutes, binds = substitute_values values
+
+      scope = @klass.unscoped
+
+      if @klass.finder_needs_type_condition?
+        scope.unscope!(where: @klass.inheritance_column)
+      end
+
+      um = scope.where(@klass.arel_table[@klass.primary_key].eq(id_was || id)).arel.compile_update(substitutes, @klass.primary_key)
+
+      @klass.connection.update(
+        um,
+        'SQL',
+        binds)
+    end
+
+    def substitute_values(values) # :nodoc:
+      substitutes = values.sort_by { |arel_attr,_| arel_attr.name }
+      binds       = substitutes.map do |arel_attr, value|
+        [@klass.columns_hash[arel_attr.name], value]
+      end
+
+      substitutes.each_with_index do |tuple, i|
+        tuple[1] = @klass.connection.substitute_at(binds[i][0], i)
+      end
+
+      [substitutes, binds]
+    end
+
+    # Initializes new record from relation while maintaining the current
+    # scope.
+    #
+    # Expects arguments in the same format as +Base.new+.
+    #
+    #   users = User.where(name: 'DHH')
+    #   user = users.new # => #<User id: nil, name: "DHH", created_at: nil, updated_at: nil>
+    #
+    # You can also pass a block to new with the new record as argument:
+    #
+    #   user = users.new { |user| user.name = 'Oscar' }
+    #   user.name # => Oscar
+    def new(*args, &block)
+      scoping { @klass.new(*args, &block) }
+    end
+
+    alias build new
+
+    # Tries to create a new record with the same scoped attributes
+    # defined in the relation. Returns the initialized object if validation fails.
+    #
+    # Expects arguments in the same format as +Base.create+.
+    #
+    # ==== Examples
+    #   users = User.where(name: 'Oscar')
+    #   users.create # #<User id: 3, name: "oscar", ...>
+    #
+    #   users.create(name: 'fxn')
+    #   users.create # #<User id: 4, name: "fxn", ...>
+    #
+    #   users.create { |user| user.name = 'tenderlove' }
+    #   # #<User id: 5, name: "tenderlove", ...>
+    #
+    #   users.create(name: nil) # validation on name
+    #   # #<User id: nil, name: nil, ...>
+    def create(*args, &block)
+      scoping { @klass.create(*args, &block) }
+    end
+
+    # Similar to #create, but calls +create!+ on the base class. Raises
+    # an exception if a validation error occurs.
+    #
+    # Expects arguments in the same format as <tt>Base.create!</tt>.
+    def create!(*args, &block)
+      scoping { @klass.create!(*args, &block) }
+    end
+
+    def first_or_create(attributes = nil, &block) # :nodoc:
+      first || create(attributes, &block)
+    end
+
+    def first_or_create!(attributes = nil, &block) # :nodoc:
+      first || create!(attributes, &block)
+    end
+
+    def first_or_initialize(attributes = nil, &block) # :nodoc:
+      first || new(attributes, &block)
+    end
+
+    # Finds the first record with the given attributes, or creates a record
+    # with the attributes if one is not found:
+    #
+    #   # Find the first user named "Penélope" or create a new one.
+    #   User.find_or_create_by(first_name: 'Penélope')
+    #   # => #<User id: 1, first_name: "Penélope", last_name: nil>
+    #
+    #   # Find the first user named "Penélope" or create a new one.
+    #   # We already have one so the existing record will be returned.
+    #   User.find_or_create_by(first_name: 'Penélope')
+    #   # => #<User id: 1, first_name: "Penélope", last_name: nil>
+    #
+    #   # Find the first user named "Scarlett" or create a new one with
+    #   # a particular last name.
+    #   User.create_with(last_name: 'Johansson').find_or_create_by(first_name: 'Scarlett')
+    #   # => #<User id: 2, first_name: "Scarlett", last_name: "Johansson">
+    #
+    # This method accepts a block, which is passed down to +create+. The last example
+    # above can be alternatively written this way:
+    #
+    #   # Find the first user named "Scarlett" or create a new one with a
+    #   # different last name.
+    #   User.find_or_create_by(first_name: 'Scarlett') do |user|
+    #     user.last_name = 'Johansson'
+    #   end
+    #   # => #<User id: 2, first_name: "Scarlett", last_name: "Johansson">
+    #
+    # This method always returns a record, but if creation was attempted and
+    # failed due to validation errors it won't be persisted, you get what
+    # +create+ returns in such situation.
+    #
+    # Please note *this method is not atomic*, it runs first a SELECT, and if
+    # there are no results an INSERT is attempted. If there are other threads
+    # or processes there is a race condition between both calls and it could
+    # be the case that you end up with two similar records.
+    #
+    # Whether that is a problem or not depends on the logic of the
+    # application, but in the particular case in which rows have a UNIQUE
+    # constraint an exception may be raised, just retry:
+    #
+    #  begin
+    #    CreditAccount.find_or_create_by(user_id: user.id)
+    #  rescue ActiveRecord::RecordNotUnique
+    #    retry
+    #  end
+    #
+    def find_or_create_by(attributes, &block)
+      find_by(attributes) || create(attributes, &block)
+    end
+
+    # Like <tt>find_or_create_by</tt>, but calls <tt>create!</tt> so an exception
+    # is raised if the created record is invalid.
+    def find_or_create_by!(attributes, &block)
+      find_by(attributes) || create!(attributes, &block)
+    end
+
+    # Like <tt>find_or_create_by</tt>, but calls <tt>new</tt> instead of <tt>create</tt>.
+    def find_or_initialize_by(attributes, &block)
+      find_by(attributes) || new(attributes, &block)
+    end
+
+    # Runs EXPLAIN on the query or queries triggered by this relation and
+    # returns the result as a string. The string is formatted imitating the
+    # ones printed by the database shell.
+    #
+    # Note that this method actually runs the queries, since the results of some
+    # are needed by the next ones when eager loading is going on.
+    #
+    # Please see further details in the
+    # {Active Record Query Interface guide}[http://guides.rubyonrails.org/active_record_querying.html#running-explain].
+    def explain
+      #TODO: Fix for binds.
+      exec_explain(collecting_queries_for_explain { exec_queries })
+    end
+
+    # Converts relation objects to Array.
+    def to_a
+      load
+      @records
+    end
+
+    # Serializes the relation objects Array.
+    def encode_with(coder)
+      coder.represent_seq(nil, to_a)
+    end
+
+    def as_json(options = nil) #:nodoc:
+      to_a.as_json(options)
+    end
+
+    # Returns size of the records.
+    def size
+      loaded? ? @records.length : count(:all)
+    end
+
+    # Returns true if there are no records.
+    def empty?
+      return @records.empty? if loaded?
+
+      if limit_value == 0
+        true
+      else
+        c = count(:all)
+        c.respond_to?(:zero?) ? c.zero? : c.empty?
+      end
+    end
+
+    # Returns true if there are any records.
+    def any?
+      if block_given?
+        to_a.any? { |*block_args| yield(*block_args) }
+      else
+        !empty?
+      end
+    end
+
+    # Returns true if there is more than one record.
+    def many?
+      if block_given?
+        to_a.many? { |*block_args| yield(*block_args) }
+      else
+        limit_value ? to_a.many? : size > 1
+      end
+    end
+
+    # Scope all queries to the current scope.
+    #
+    #   Comment.where(post_id: 1).scoping do
+    #     Comment.first
+    #   end
+    #   # => SELECT "comments".* FROM "comments" WHERE "comments"."post_id" = 1 ORDER BY "comments"."id" ASC LIMIT 1
+    #
+    # Please check unscoped if you want to remove all previous scopes (including
+    # the default_scope) during the execution of a block.
+    def scoping
+      previous, klass.current_scope = klass.current_scope, self
+      yield
+    ensure
+      klass.current_scope = previous
+    end
+
+    # Updates all records with details given if they match a set of conditions supplied, limits and order can
+    # also be supplied. This method constructs a single SQL UPDATE statement and sends it straight to the
+    # database. It does not instantiate the involved models and it does not trigger Active Record callbacks
+    # or validations.
+    #
+    # ==== Parameters
+    #
+    # * +updates+ - A string, array, or hash representing the SET part of an SQL statement.
+    #
+    # ==== Examples
+    #
+    #   # Update all customers with the given attributes
+    #   Customer.update_all wants_email: true
+    #
+    #   # Update all books with 'Rails' in their title
+    #   Book.where('title LIKE ?', '%Rails%').update_all(author: 'David')
+    #
+    #   # Update all books that match conditions, but limit it to 5 ordered by date
+    #   Book.where('title LIKE ?', '%Rails%').order(:created_at).limit(5).update_all(author: 'David')
+    def update_all(updates)
+      raise ArgumentError, "Empty list of attributes to change" if updates.blank?
+
+      stmt = Arel::UpdateManager.new(arel.engine)
+
+      stmt.set Arel.sql(@klass.send(:sanitize_sql_for_assignment, updates))
+      stmt.table(table)
+      stmt.key = table[primary_key]
+
+      if joins_values.any?
+        @klass.connection.join_to_update(stmt, arel)
+      else
+        stmt.take(arel.limit)
+        stmt.order(*arel.orders)
+        stmt.wheres = arel.constraints
+      end
+
+      bvs = bind_values + arel.bind_values
+      @klass.connection.update stmt, 'SQL', bvs
+    end
+
+    # Updates an object (or multiple objects) and saves it to the database, if validations pass.
+    # The resulting object is returned whether the object was saved successfully to the database or not.
+    #
+    # ==== Parameters
+    #
+    # * +id+ - This should be the id or an array of ids to be updated.
+    # * +attributes+ - This should be a hash of attributes or an array of hashes.
+    #
+    # ==== Examples
+    #
+    #   # Updates one record
+    #   Person.update(15, user_name: 'Samuel', group: 'expert')
+    #
+    #   # Updates multiple records
+    #   people = { 1 => { "first_name" => "David" }, 2 => { "first_name" => "Jeremy" } }
+    #   Person.update(people.keys, people.values)
+    def update(id, attributes)
+      if id.is_a?(Array)
+        id.map.with_index { |one_id, idx| update(one_id, attributes[idx]) }
+      else
+        object = find(id)
+        object.update(attributes)
+        object
+      end
+    end
+
+    # Destroys the records matching +conditions+ by instantiating each
+    # record and calling its +destroy+ method. Each object's callbacks are
+    # executed (including <tt>:dependent</tt> association options). Returns the
+    # collection of objects that were destroyed; each will be frozen, to
+    # reflect that no changes should be made (since they can't be persisted).
+    #
+    # Note: Instantiation, callback execution, and deletion of each
+    # record can be time consuming when you're removing many records at
+    # once. It generates at least one SQL +DELETE+ query per record (or
+    # possibly more, to enforce your callbacks). If you want to delete many
+    # rows quickly, without concern for their associations or callbacks, use
+    # +delete_all+ instead.
+    #
+    # ==== Parameters
+    #
+    # * +conditions+ - A string, array, or hash that specifies which records
+    #   to destroy. If omitted, all records are destroyed. See the
+    #   Conditions section in the introduction to ActiveRecord::Base for
+    #   more information.
+    #
+    # ==== Examples
+    #
+    #   Person.destroy_all("last_login < '2004-04-04'")
+    #   Person.destroy_all(status: "inactive")
+    #   Person.where(age: 0..18).destroy_all
+    def destroy_all(conditions = nil)
+      if conditions
+        where(conditions).destroy_all
+      else
+        to_a.each {|object| object.destroy }.tap { reset }
+      end
+    end
+
+    # Destroy an object (or multiple objects) that has the given id. The object is instantiated first,
+    # therefore all callbacks and filters are fired off before the object is deleted. This method is
+    # less efficient than ActiveRecord#delete but allows cleanup methods and other actions to be run.
+    #
+    # This essentially finds the object (or multiple objects) with the given id, creates a new object
+    # from the attributes, and then calls destroy on it.
+    #
+    # ==== Parameters
+    #
+    # * +id+ - Can be either an Integer or an Array of Integers.
+    #
+    # ==== Examples
+    #
+    #   # Destroy a single object
+    #   Todo.destroy(1)
+    #
+    #   # Destroy multiple objects
+    #   todos = [1,2,3]
+    #   Todo.destroy(todos)
+    def destroy(id)
+      if id.is_a?(Array)
+        id.map { |one_id| destroy(one_id) }
+      else
+        find(id).destroy
+      end
+    end
+
+    # Deletes the records matching +conditions+ without instantiating the records
+    # first, and hence not calling the +destroy+ method nor invoking callbacks. This
+    # is a single SQL DELETE statement that goes straight to the database, much more
+    # efficient than +destroy_all+. Be careful with relations though, in particular
+    # <tt>:dependent</tt> rules defined on associations are not honored. Returns the
+    # number of rows affected.
+    #
+    #   Post.delete_all("person_id = 5 AND (category = 'Something' OR category = 'Else')")
+    #   Post.delete_all(["person_id = ? AND (category = ? OR category = ?)", 5, 'Something', 'Else'])
+    #   Post.where(person_id: 5).where(category: ['Something', 'Else']).delete_all
+    #
+    # Both calls delete the affected posts all at once with a single DELETE statement.
+    # If you need to destroy dependent associations or call your <tt>before_*</tt> or
+    # +after_destroy+ callbacks, use the +destroy_all+ method instead.
+    #
+    # If an invalid method is supplied, +delete_all+ raises an ActiveRecord error:
+    #
+    #   Post.limit(100).delete_all
+    #   # => ActiveRecord::ActiveRecordError: delete_all doesn't support limit
+    def delete_all(conditions = nil)
+      invalid_methods = INVALID_METHODS_FOR_DELETE_ALL.select { |method|
+        if MULTI_VALUE_METHODS.include?(method)
+          send("#{method}_values").any?
+        else
+          send("#{method}_value")
+        end
+      }
+      if invalid_methods.any?
+        raise ActiveRecordError.new("delete_all doesn't support #{invalid_methods.join(', ')}")
+      end
+
+      if conditions
+        where(conditions).delete_all
+      else
+        stmt = Arel::DeleteManager.new(arel.engine)
+        stmt.from(table)
+
+        if joins_values.any?
+          @klass.connection.join_to_delete(stmt, arel, table[primary_key])
+        else
+          stmt.wheres = arel.constraints
+        end
+
+        affected = @klass.connection.delete(stmt, 'SQL', bind_values)
+
+        reset
+        affected
+      end
+    end
+
+    # Deletes the row with a primary key matching the +id+ argument, using a
+    # SQL +DELETE+ statement, and returns the number of rows deleted. Active
+    # Record objects are not instantiated, so the object's callbacks are not
+    # executed, including any <tt>:dependent</tt> association options.
+    #
+    # You can delete multiple rows at once by passing an Array of <tt>id</tt>s.
+    #
+    # Note: Although it is often much faster than the alternative,
+    # <tt>#destroy</tt>, skipping callbacks might bypass business logic in
+    # your application that ensures referential integrity or performs other
+    # essential jobs.
+    #
+    # ==== Examples
+    #
+    #   # Delete a single row
+    #   Todo.delete(1)
+    #
+    #   # Delete multiple rows
+    #   Todo.delete([2,3,4])
+    def delete(id_or_array)
+      where(primary_key => id_or_array).delete_all
+    end
+
+    # Causes the records to be loaded from the database if they have not
+    # been loaded already. You can use this if for some reason you need
+    # to explicitly load some records before actually using them. The
+    # return value is the relation itself, not the records.
+    #
+    #   Post.where(published: true).load # => #<ActiveRecord::Relation>
+    def load
+      exec_queries unless loaded?
+
+      self
+    end
+
+    # Forces reloading of relation.
+    def reload
+      reset
+      load
+    end
+
+    def reset
+      @last = @to_sql = @order_clause = @scope_for_create = @arel = @loaded = nil
+      @should_eager_load = @join_dependency = nil
+      @records = []
+      @offsets = {}
+      self
+    end
+
+    # Returns sql statement for the relation.
+    #
+    #   User.where(name: 'Oscar').to_sql
+    #   # => SELECT "users".* FROM "users"  WHERE "users"."name" = 'Oscar'
+    def to_sql
+      @to_sql ||= begin
+                    relation   = self
+                    connection = klass.connection
+                    visitor    = connection.visitor
+
+                    if eager_loading?
+                      find_with_associations { |rel| relation = rel }
+                    end
+
+                    arel  = relation.arel
+                    binds = (arel.bind_values + relation.bind_values).dup
+                    binds.map! { |bv| connection.quote(*bv.reverse) }
+                    collect = visitor.accept(arel.ast, Arel::Collectors::Bind.new)
+                    collect.substitute_binds(binds).join
+                  end
+    end
+
+    # Returns a hash of where conditions.
+    #
+    #   User.where(name: 'Oscar').where_values_hash
+    #   # => {name: "Oscar"}
+    def where_values_hash(relation_table_name = table_name)
+      equalities = where_values.grep(Arel::Nodes::Equality).find_all { |node|
+        node.left.relation.name == relation_table_name
+      }
+
+      binds = Hash[bind_values.find_all(&:first).map { |column, v| [column.name, v] }]
+
+      Hash[equalities.map { |where|
+        name = where.left.name
+        [name, binds.fetch(name.to_s) {
+          case where.right
+          when Array then where.right.map(&:val)
+          else
+            where.right.val
+          end
+        }]
+      }]
+    end
+
+    def scope_for_create
+      @scope_for_create ||= where_values_hash.merge(create_with_value)
+    end
+
+    # Returns true if relation needs eager loading.
+    def eager_loading?
+      @should_eager_load ||=
+        eager_load_values.any? ||
+        includes_values.any? && (joined_includes_values.any? || references_eager_loaded_tables?)
+    end
+
+    # Joins that are also marked for preloading. In which case we should just eager load them.
+    # Note that this is a naive implementation because we could have strings and symbols which
+    # represent the same association, but that aren't matched by this. Also, we could have
+    # nested hashes which partially match, e.g. { a: :b } & { a: [:b, :c] }
+    def joined_includes_values
+      includes_values & joins_values
+    end
+
+    # +uniq+ and +uniq!+ are silently deprecated. +uniq_value+ delegates to +distinct_value+
+    # to maintain backwards compatibility. Use +distinct_value+ instead.
+    def uniq_value
+      distinct_value
+    end
+
+    # Compares two relations for equality.
+    def ==(other)
+      case other
+      when Associations::CollectionProxy, AssociationRelation
+        self == other.to_a
+      when Relation
+        other.to_sql == to_sql
+      when Array
+        to_a == other
+      end
+    end
+
+    def pretty_print(q)
+      q.pp(self.to_a)
+    end
+
+    # Returns true if relation is blank.
+    def blank?
+      to_a.blank?
+    end
+
+    def values
+      Hash[@values]
+    end
+
+    def inspect
+      entries = to_a.take([limit_value, 11].compact.min).map!(&:inspect)
+      entries[10] = '...' if entries.size == 11
+
+      "#<#{self.class.name} [#{entries.join(', ')}]>"
+    end
+
+    private
+
+    def exec_queries
+      @records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel, arel.bind_values + bind_values)
+
+      preload = preload_values
+      preload +=  includes_values unless eager_loading?
+      preloader = ActiveRecord::Associations::Preloader.new
+      preload.each do |associations|
+        preloader.preload @records, associations
+      end
+
+      @records.each { |record| record.readonly! } if readonly_value
+
+      @loaded = true
+      @records
+    end
+
+    def references_eager_loaded_tables?
+      joined_tables = arel.join_sources.map do |join|
+        if join.is_a?(Arel::Nodes::StringJoin)
+          tables_in_string(join.left)
+        else
+          [join.left.table_name, join.left.table_alias]
+        end
+      end
+
+      joined_tables += [table.name, table.table_alias]
+
+      # always convert table names to downcase as in Oracle quoted table names are in uppercase
+      joined_tables = joined_tables.flatten.compact.map { |t| t.downcase }.uniq
+
+      (references_values - joined_tables).any?
+    end
+
+    def tables_in_string(string)
+      return [] if string.blank?
+      # always convert table names to downcase as in Oracle quoted table names are in uppercase
+      # ignore raw_sql_ that is used by Oracle adapter as alias for limit/offset subqueries
+      string.scan(/([a-zA-Z_][.\w]+).?\./).flatten.map{ |s| s.downcase }.uniq - ['raw_sql_']
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/batches.rb b/activerecord/lib/active_record/relation/batches.rb
new file mode 100644
index 0000000000..b069cdce7c
--- /dev/null
+++ b/activerecord/lib/active_record/relation/batches.rb
@@ -0,0 +1,138 @@
+module ActiveRecord
+  module Batches
+    # Looping through a collection of records from the database
+    # (using the +all+ method, for example) is very inefficient
+    # since it will try to instantiate all the objects at once.
+    #
+    # In that case, batch processing methods allow you to work
+    # with the records in batches, thereby greatly reducing memory consumption.
+    #
+    # The #find_each method uses #find_in_batches with a batch size of 1000 (or as
+    # specified by the +:batch_size+ option).
+    #
+    #   Person.find_each do |person|
+    #     person.do_awesome_stuff
+    #   end
+    #
+    #   Person.where("age > 21").find_each do |person|
+    #     person.party_all_night!
+    #   end
+    #
+    # If you do not provide a block to #find_each, it will return an Enumerator
+    # for chaining with other methods:
+    #
+    #   Person.find_each.with_index do |person, index|
+    #     person.award_trophy(index + 1)
+    #   end
+    #
+    # ==== Options
+    # * <tt>:batch_size</tt> - Specifies the size of the batch. Default to 1000.
+    # * <tt>:start</tt> - Specifies the starting point for the batch processing.
+    # This is especially useful if you want multiple workers dealing with
+    # the same processing queue. You can make worker 1 handle all the records
+    # between id 0 and 10,000 and worker 2 handle from 10,000 and beyond
+    # (by setting the +:start+ option on that worker).
+    #
+    #   # Let's process for a batch of 2000 records, skipping the first 2000 rows
+    #   Person.find_each(start: 2000, batch_size: 2000) do |person|
+    #     person.party_all_night!
+    #   end
+    #
+    # NOTE: It's not possible to set the order. That is automatically set to
+    # ascending on the primary key ("id ASC") to make the batch ordering
+    # work. This also means that this method only works with integer-based
+    # primary keys.
+    #
+    # NOTE: You can't set the limit either, that's used to control
+    # the batch sizes.
+    def find_each(options = {})
+      if block_given?
+        find_in_batches(options) do |records|
+          records.each { |record| yield record }
+        end
+      else
+        enum_for :find_each, options do
+          options[:start] ? where(table[primary_key].gteq(options[:start])).size : size
+        end
+      end
+    end
+
+    # Yields each batch of records that was found by the find +options+ as
+    # an array.
+    #
+    #   Person.where("age > 21").find_in_batches do |group|
+    #     sleep(50) # Make sure it doesn't get too crowded in there!
+    #     group.each { |person| person.party_all_night! }
+    #   end
+    #
+    # If you do not provide a block to #find_in_batches, it will return an Enumerator
+    # for chaining with other methods:
+    #
+    #   Person.find_in_batches.with_index do |group, batch|
+    #     puts "Processing group ##{batch}"
+    #     group.each(&:recover_from_last_night!)
+    #   end
+    #
+    # To be yielded each record one by one, use #find_each instead.
+    #
+    # ==== Options
+    # * <tt>:batch_size</tt> - Specifies the size of the batch. Default to 1000.
+    # * <tt>:start</tt> - Specifies the starting point for the batch processing.
+    # This is especially useful if you want multiple workers dealing with
+    # the same processing queue. You can make worker 1 handle all the records
+    # between id 0 and 10,000 and worker 2 handle from 10,000 and beyond
+    # (by setting the +:start+ option on that worker).
+    #
+    #   # Let's process the next 2000 records
+    #   Person.find_in_batches(start: 2000, batch_size: 2000) do |group|
+    #     group.each { |person| person.party_all_night! }
+    #   end
+    #
+    # NOTE: It's not possible to set the order. That is automatically set to
+    # ascending on the primary key ("id ASC") to make the batch ordering
+    # work. This also means that this method only works with integer-based
+    # primary keys.
+    #
+    # NOTE: You can't set the limit either, that's used to control
+    # the batch sizes.
+    def find_in_batches(options = {})
+      options.assert_valid_keys(:start, :batch_size)
+
+      relation = self
+      start = options[:start]
+      batch_size = options[:batch_size] || 1000
+
+      unless block_given?
+        return to_enum(:find_in_batches, options) do
+          total = start ? where(table[primary_key].gteq(start)).size : size
+          (total - 1).div(batch_size) + 1
+        end
+      end
+
+      if logger && (arel.orders.present? || arel.taken.present?)
+        logger.warn("Scoped order and limit are ignored, it's forced to be batch order and batch size")
+      end
+
+      relation = relation.reorder(batch_order).limit(batch_size)
+      records = start ? relation.where(table[primary_key].gteq(start)).to_a : relation.to_a
+
+      while records.any?
+        records_size = records.size
+        primary_key_offset = records.last.id
+        raise "Primary key not included in the custom select clause" unless primary_key_offset
+
+        yield records
+
+        break if records_size < batch_size
+
+        records = relation.where(table[primary_key].gt(primary_key_offset)).to_a
+      end
+    end
+
+    private
+
+    def batch_order
+      "#{quoted_table_name}.#{quoted_primary_key} ASC"
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
new file mode 100644
index 0000000000..90e99957f6
--- /dev/null
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -0,0 +1,402 @@
+module ActiveRecord
+  module Calculations
+    # Count the records.
+    #
+    #   Person.count
+    #   # => the total count of all people
+    #
+    #   Person.count(:age)
+    #   # => returns the total count of all people whose age is present in database
+    #
+    #   Person.count(:all)
+    #   # => performs a COUNT(*) (:all is an alias for '*')
+    #
+    #   Person.distinct.count(:age)
+    #   # => counts the number of different age values
+    #
+    # If +count+ is used with +group+, it returns a Hash whose keys represent the aggregated column,
+    # and the values are the respective amounts:
+    #
+    #   Person.group(:city).count
+    #   # => { 'Rome' => 5, 'Paris' => 3 }
+    # 
+    # If +count+ is used with +group+ for multiple columns, it returns a Hash whose 
+    # keys are an array containing the individual values of each column and the value 
+    # of each key would be the +count+.
+    # 
+    #   Article.group(:status, :category).count
+    #   # =>  {["draft", "business"]=>10, ["draft", "technology"]=>4, 
+    #          ["published", "business"]=>0, ["published", "technology"]=>2}
+    # 
+    # If +count+ is used with +select+, it will count the selected columns:
+    #
+    #   Person.select(:age).count
+    #   # => counts the number of different age values
+    #
+    # Note: not all valid +select+ expressions are valid +count+ expressions. The specifics differ
+    # between databases. In invalid cases, an error from the database is thrown.
+    def count(column_name = nil, options = {})
+      # TODO: Remove options argument as soon we remove support to
+      # activerecord-deprecated_finders.
+      column_name, options = nil, column_name if column_name.is_a?(Hash)
+      calculate(:count, column_name, options)
+    end
+
+    # Calculates the average value on a given column. Returns +nil+ if there's
+    # no row. See +calculate+ for examples with options.
+    #
+    #   Person.average(:age) # => 35.8
+    def average(column_name, options = {})
+      # TODO: Remove options argument as soon we remove support to
+      # activerecord-deprecated_finders.
+      calculate(:average, column_name, options)
+    end
+
+    # Calculates the minimum value on a given column. The value is returned
+    # with the same data type of the column, or +nil+ if there's no row. See
+    # +calculate+ for examples with options.
+    #
+    #   Person.minimum(:age) # => 7
+    def minimum(column_name, options = {})
+      # TODO: Remove options argument as soon we remove support to
+      # activerecord-deprecated_finders.
+      calculate(:minimum, column_name, options)
+    end
+
+    # Calculates the maximum value on a given column. The value is returned
+    # with the same data type of the column, or +nil+ if there's no row. See
+    # +calculate+ for examples with options.
+    #
+    #   Person.maximum(:age) # => 93
+    def maximum(column_name, options = {})
+      # TODO: Remove options argument as soon we remove support to
+      # activerecord-deprecated_finders.
+      calculate(:maximum, column_name, options)
+    end
+
+    # Calculates the sum of values on a given column. The value is returned
+    # with the same data type of the column, 0 if there's no row. See
+    # +calculate+ for examples with options.
+    #
+    #   Person.sum(:age) # => 4562
+    def sum(*args)
+      calculate(:sum, *args)
+    end
+
+    # This calculates aggregate values in the given column. Methods for count, sum, average,
+    # minimum, and maximum have been added as shortcuts.
+    #
+    # There are two basic forms of output:
+    #
+    #   * Single aggregate value: The single value is type cast to Fixnum for COUNT, Float
+    #     for AVG, and the given column's type for everything else.
+    #
+    #   * Grouped values: This returns an ordered hash of the values and groups them. It
+    #     takes either a column name, or the name of a belongs_to association.
+    #
+    #       values = Person.group('last_name').maximum(:age)
+    #       puts values["Drake"]
+    #       # => 43
+    #
+    #       drake  = Family.find_by(last_name: 'Drake')
+    #       values = Person.group(:family).maximum(:age) # Person belongs_to :family
+    #       puts values[drake]
+    #       # => 43
+    #
+    #       values.each do |family, max_age|
+    #       ...
+    #       end
+    #
+    #   Person.calculate(:count, :all) # The same as Person.count
+    #   Person.average(:age) # SELECT AVG(age) FROM people...
+    #
+    #   # Selects the minimum age for any family without any minors
+    #   Person.group(:last_name).having("min(age) > 17").minimum(:age)
+    #
+    #   Person.sum("2 * age")
+    def calculate(operation, column_name, options = {})
+      # TODO: Remove options argument as soon we remove support to
+      # activerecord-deprecated_finders.
+      if column_name.is_a?(Symbol) && attribute_alias?(column_name)
+        column_name = attribute_alias(column_name)
+      end
+
+      if has_include?(column_name)
+        construct_relation_for_association_calculations.calculate(operation, column_name, options)
+      else
+        perform_calculation(operation, column_name, options)
+      end
+    end
+
+    # Use <tt>pluck</tt> as a shortcut to select one or more attributes without
+    # loading a bunch of records just to grab the attributes you want.
+    #
+    #   Person.pluck(:name)
+    #
+    # instead of
+    #
+    #   Person.all.map(&:name)
+    #
+    # Pluck returns an <tt>Array</tt> of attribute values type-casted to match
+    # the plucked column names, if they can be deduced. Plucking an SQL fragment
+    # returns String values by default.
+    #
+    #   Person.pluck(:id)
+    #   # SELECT people.id FROM people
+    #   # => [1, 2, 3]
+    #
+    #   Person.pluck(:id, :name)
+    #   # SELECT people.id, people.name FROM people
+    #   # => [[1, 'David'], [2, 'Jeremy'], [3, 'Jose']]
+    #
+    #   Person.pluck('DISTINCT role')
+    #   # SELECT DISTINCT role FROM people
+    #   # => ['admin', 'member', 'guest']
+    #
+    #   Person.where(age: 21).limit(5).pluck(:id)
+    #   # SELECT people.id FROM people WHERE people.age = 21 LIMIT 5
+    #   # => [2, 3]
+    #
+    #   Person.pluck('DATEDIFF(updated_at, created_at)')
+    #   # SELECT DATEDIFF(updated_at, created_at) FROM people
+    #   # => ['0', '27761', '173']
+    #
+    def pluck(*column_names)
+      column_names.map! do |column_name|
+        if column_name.is_a?(Symbol) && attribute_alias?(column_name)
+          attribute_alias(column_name)
+        else
+          column_name.to_s
+        end
+      end
+
+      if has_include?(column_names.first)
+        construct_relation_for_association_calculations.pluck(*column_names)
+      else
+        relation = spawn
+        relation.select_values = column_names.map { |cn|
+          columns_hash.key?(cn) ? arel_table[cn] : cn
+        }
+        result = klass.connection.select_all(relation.arel, nil, bind_values)
+        result.cast_values(klass.column_types)
+      end
+    end
+
+    # Pluck all the ID's for the relation using the table's primary key
+    #
+    #   Person.ids # SELECT people.id FROM people
+    #   Person.joins(:companies).ids # SELECT people.id FROM people INNER JOIN companies ON companies.person_id = people.id
+    def ids
+      pluck primary_key
+    end
+
+    private
+
+    def has_include?(column_name)
+      eager_loading? || (includes_values.present? && ((column_name && column_name != :all) || references_eager_loaded_tables?))
+    end
+
+    def perform_calculation(operation, column_name, options = {})
+      # TODO: Remove options argument as soon we remove support to
+      # activerecord-deprecated_finders.
+      operation = operation.to_s.downcase
+
+      # If #count is used with #distinct / #uniq it is considered distinct. (eg. relation.distinct.count)
+      distinct = self.distinct_value
+
+      if operation == "count"
+        column_name ||= select_for_count
+
+        unless arel.ast.grep(Arel::Nodes::OuterJoin).empty?
+          distinct = true
+        end
+
+        column_name = primary_key if column_name == :all && distinct
+        distinct = nil if column_name =~ /\s*DISTINCT[\s(]+/i
+      end
+
+      if group_values.any?
+        execute_grouped_calculation(operation, column_name, distinct)
+      else
+        execute_simple_calculation(operation, column_name, distinct)
+      end
+    end
+
+    def aggregate_column(column_name)
+      if @klass.column_names.include?(column_name.to_s)
+        Arel::Attribute.new(@klass.unscoped.table, column_name)
+      else
+        Arel.sql(column_name == :all ? "*" : column_name.to_s)
+      end
+    end
+
+    def operation_over_aggregate_column(column, operation, distinct)
+      operation == 'count' ? column.count(distinct) : column.send(operation)
+    end
+
+    def execute_simple_calculation(operation, column_name, distinct) #:nodoc:
+      # Postgresql doesn't like ORDER BY when there are no GROUP BY
+      relation = unscope(:order)
+
+      column_alias = column_name
+
+      bind_values = nil
+
+      if operation == "count" && (relation.limit_value || relation.offset_value)
+        # Shortcut when limit is zero.
+        return 0 if relation.limit_value == 0
+
+        query_builder = build_count_subquery(relation, column_name, distinct)
+        bind_values = query_builder.bind_values + relation.bind_values
+      else
+        column = aggregate_column(column_name)
+
+        select_value = operation_over_aggregate_column(column, operation, distinct)
+
+        column_alias = select_value.alias
+        relation.select_values = [select_value]
+
+        query_builder = relation.arel
+        bind_values = query_builder.bind_values + relation.bind_values
+      end
+
+      result = @klass.connection.select_all(query_builder, nil, bind_values)
+      row    = result.first
+      value  = row && row.values.first
+      column = result.column_types.fetch(column_alias) do
+        type_for(column_name)
+      end
+
+      type_cast_calculated_value(value, column, operation)
+    end
+
+    def execute_grouped_calculation(operation, column_name, distinct) #:nodoc:
+      group_attrs = group_values
+
+      if group_attrs.first.respond_to?(:to_sym)
+        association  = @klass._reflect_on_association(group_attrs.first.to_sym)
+        associated   = group_attrs.size == 1 && association && association.belongs_to? # only count belongs_to associations
+        group_fields = Array(associated ? association.foreign_key : group_attrs)
+      else
+        group_fields = group_attrs
+      end
+
+      group_aliases = group_fields.map { |field|
+        column_alias_for(field)
+      }
+      group_columns = group_aliases.zip(group_fields).map { |aliaz,field|
+        [aliaz, field]
+      }
+
+      group = group_fields
+
+      if operation == 'count' && column_name == :all
+        aggregate_alias = 'count_all'
+      else
+        aggregate_alias = column_alias_for([operation, column_name].join(' '))
+      end
+
+      select_values = [
+        operation_over_aggregate_column(
+          aggregate_column(column_name),
+          operation,
+          distinct).as(aggregate_alias)
+      ]
+      select_values += select_values unless having_values.empty?
+
+      select_values.concat group_fields.zip(group_aliases).map { |field,aliaz|
+        if field.respond_to?(:as)
+          field.as(aliaz)
+        else
+          "#{field} AS #{aliaz}"
+        end
+      }
+
+      relation = except(:group)
+      relation.group_values  = group
+      relation.select_values = select_values
+
+      calculated_data = @klass.connection.select_all(relation, nil, bind_values)
+
+      if association
+        key_ids     = calculated_data.collect { |row| row[group_aliases.first] }
+        key_records = association.klass.base_class.find(key_ids)
+        key_records = Hash[key_records.map { |r| [r.id, r] }]
+      end
+
+      Hash[calculated_data.map do |row|
+        key = group_columns.map { |aliaz, col_name|
+          column = calculated_data.column_types.fetch(aliaz) do
+            type_for(col_name)
+          end
+          type_cast_calculated_value(row[aliaz], column)
+        }
+        key = key.first if key.size == 1
+        key = key_records[key] if associated
+
+        column_type = calculated_data.column_types.fetch(aggregate_alias) { type_for(column_name) }
+        [key, type_cast_calculated_value(row[aggregate_alias], column_type, operation)]
+      end]
+    end
+
+    # Converts the given keys to the value that the database adapter returns as
+    # a usable column name:
+    #
+    #   column_alias_for("users.id")                 # => "users_id"
+    #   column_alias_for("sum(id)")                  # => "sum_id"
+    #   column_alias_for("count(distinct users.id)") # => "count_distinct_users_id"
+    #   column_alias_for("count(*)")                 # => "count_all"
+    #   column_alias_for("count", "id")              # => "count_id"
+    def column_alias_for(keys)
+      if keys.respond_to? :name
+        keys = "#{keys.relation.name}.#{keys.name}"
+      end
+
+      table_name = keys.to_s.downcase
+      table_name.gsub!(/\*/, 'all')
+      table_name.gsub!(/\W+/, ' ')
+      table_name.strip!
+      table_name.gsub!(/ +/, '_')
+
+      @klass.connection.table_alias_for(table_name)
+    end
+
+    def type_for(field)
+      field_name = field.respond_to?(:name) ? field.name.to_s : field.to_s.split('.').last
+      @klass.type_for_attribute(field_name)
+    end
+
+    def type_cast_calculated_value(value, type, operation = nil)
+      case operation
+        when 'count'   then value.to_i
+        when 'sum'     then type.type_cast_from_database(value || 0)
+        when 'average' then value.respond_to?(:to_d) ? value.to_d : value
+        else type.type_cast_from_database(value)
+      end
+    end
+
+    # TODO: refactor to allow non-string `select_values` (eg. Arel nodes).
+    def select_for_count
+      if select_values.present?
+        select_values.join(", ")
+      else
+        :all
+      end
+    end
+
+    def build_count_subquery(relation, column_name, distinct)
+      column_alias = Arel.sql('count_column')
+      subquery_alias = Arel.sql('subquery_for_count')
+
+      aliased_column = aggregate_column(column_name == :all ? 1 : column_name).as(column_alias)
+      relation.select_values = [aliased_column]
+      arel = relation.arel
+      subquery = arel.as(subquery_alias)
+
+      sm = Arel::SelectManager.new relation.engine
+      sm.bind_values = arel.bind_values
+      select_value = operation_over_aggregate_column(column_alias, 'count', distinct)
+      sm.project(select_value).from(subquery)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/delegation.rb b/activerecord/lib/active_record/relation/delegation.rb
new file mode 100644
index 0000000000..50f4d5c7ab
--- /dev/null
+++ b/activerecord/lib/active_record/relation/delegation.rb
@@ -0,0 +1,140 @@
+require 'set'
+require 'active_support/concern'
+require 'active_support/deprecation'
+
+module ActiveRecord
+  module Delegation # :nodoc:
+    module DelegateCache
+      def relation_delegate_class(klass) # :nodoc:
+        @relation_delegate_cache[klass]
+      end
+
+      def initialize_relation_delegate_cache # :nodoc:
+        @relation_delegate_cache = cache = {}
+        [
+          ActiveRecord::Relation,
+          ActiveRecord::Associations::CollectionProxy,
+          ActiveRecord::AssociationRelation
+        ].each do |klass|
+          delegate = Class.new(klass) {
+            include ClassSpecificRelation
+          }
+          const_set klass.name.gsub('::', '_'), delegate
+          cache[klass] = delegate
+        end
+      end
+
+      def inherited(child_class)
+        child_class.initialize_relation_delegate_cache
+        super
+      end
+    end
+
+    extend ActiveSupport::Concern
+
+    # This module creates compiled delegation methods dynamically at runtime, which makes
+    # subsequent calls to that method faster by avoiding method_missing. The delegations
+    # may vary depending on the klass of a relation, so we create a subclass of Relation
+    # for each different klass, and the delegations are compiled into that subclass only.
+
+    BLACKLISTED_ARRAY_METHODS = [
+      :compact!, :flatten!, :reject!, :reverse!, :rotate!, :map!,
+      :shuffle!, :slice!, :sort!, :sort_by!, :delete_if,
+      :keep_if, :pop, :shift, :delete_at, :compact, :select!
+    ].to_set # :nodoc:
+
+    delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to_ary, :join, to: :to_a
+
+    delegate :table_name, :quoted_table_name, :primary_key, :quoted_primary_key,
+             :connection, :columns_hash, :to => :klass
+
+    module ClassSpecificRelation # :nodoc:
+      extend ActiveSupport::Concern
+
+      included do
+        @delegation_mutex = Mutex.new
+      end
+
+      module ClassMethods # :nodoc:
+        def name
+          superclass.name
+        end
+
+        def delegate_to_scoped_klass(method)
+          @delegation_mutex.synchronize do
+            return if method_defined?(method)
+
+            if method.to_s =~ /\A[a-zA-Z_]\w*[!?]?\z/
+              module_eval <<-RUBY, __FILE__, __LINE__ + 1
+                def #{method}(*args, &block)
+                  scoping { @klass.#{method}(*args, &block) }
+                end
+              RUBY
+            else
+              define_method method do |*args, &block|
+                scoping { @klass.public_send(method, *args, &block) }
+              end
+            end
+          end
+        end
+
+        def delegate(method, opts = {})
+          @delegation_mutex.synchronize do
+            return if method_defined?(method)
+            super
+          end
+        end
+      end
+
+      protected
+
+      def method_missing(method, *args, &block)
+        if @klass.respond_to?(method)
+          self.class.delegate_to_scoped_klass(method)
+          scoping { @klass.public_send(method, *args, &block) }
+        elsif arel.respond_to?(method)
+          self.class.delegate method, :to => :arel
+          arel.public_send(method, *args, &block)
+        else
+          super
+        end
+      end
+    end
+
+    module ClassMethods # :nodoc:
+      def create(klass, *args)
+        relation_class_for(klass).new(klass, *args)
+      end
+
+      private
+
+      def relation_class_for(klass)
+        klass.relation_delegate_class(self)
+      end
+    end
+
+    def respond_to?(method, include_private = false)
+      super || @klass.respond_to?(method, include_private) ||
+        array_delegable?(method) ||
+        arel.respond_to?(method, include_private)
+    end
+
+    protected
+
+    def array_delegable?(method)
+      Array.method_defined?(method) && BLACKLISTED_ARRAY_METHODS.exclude?(method)
+    end
+
+    def method_missing(method, *args, &block)
+      if @klass.respond_to?(method)
+        scoping { @klass.public_send(method, *args, &block) }
+      elsif array_delegable?(method)
+        to_a.public_send(method, *args, &block)
+      elsif arel.respond_to?(method)
+        arel.public_send(method, *args, &block)
+      else
+        super
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
new file mode 100644
index 0000000000..0c9c761f97
--- /dev/null
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -0,0 +1,515 @@
+require 'active_support/deprecation'
+
+module ActiveRecord
+  module FinderMethods
+    ONE_AS_ONE = '1 AS one'
+
+    # Find by id - This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]).
+    # If no record can be found for all of the listed ids, then RecordNotFound will be raised. If the primary key
+    # is an integer, find by id coerces its arguments using +to_i+.
+    #
+    #   Person.find(1)          # returns the object for ID = 1
+    #   Person.find("1")        # returns the object for ID = 1
+    #   Person.find("31-sarah") # returns the object for ID = 31
+    #   Person.find(1, 2, 6)    # returns an array for objects with IDs in (1, 2, 6)
+    #   Person.find([7, 17])    # returns an array for objects with IDs in (7, 17)
+    #   Person.find([1])        # returns an array for the object with ID = 1
+    #   Person.where("administrator = 1").order("created_on DESC").find(1)
+    #
+    # <tt>ActiveRecord::RecordNotFound</tt> will be raised if one or more ids are not found.
+    #
+    # NOTE: The returned records may not be in the same order as the ids you
+    # provide since database rows are unordered. You'd need to provide an explicit <tt>order</tt>
+    # option if you want the results are sorted.
+    #
+    # ==== Find with lock
+    #
+    # Example for find with a lock: Imagine two concurrent transactions:
+    # each will read <tt>person.visits == 2</tt>, add 1 to it, and save, resulting
+    # in two saves of <tt>person.visits = 3</tt>. By locking the row, the second
+    # transaction has to wait until the first is finished; we get the
+    # expected <tt>person.visits == 4</tt>.
+    #
+    #   Person.transaction do
+    #     person = Person.lock(true).find(1)
+    #     person.visits += 1
+    #     person.save!
+    #   end
+    #
+    # ==== Variations of +find+
+    #
+    #   Person.where(name: 'Spartacus', rating: 4)
+    #   # returns a chainable list (which can be empty).
+    #
+    #   Person.find_by(name: 'Spartacus', rating: 4)
+    #   # returns the first item or nil.
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).first_or_initialize
+    #   # returns the first item or returns a new instance (requires you call .save to persist against the database).
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).first_or_create
+    #   # returns the first item or creates it and returns it, available since Rails 3.2.1.
+    #
+    # ==== Alternatives for +find+
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).exists?(conditions = :none)
+    #   # returns a boolean indicating if any record with the given conditions exist.
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).select("field1, field2, field3")
+    #   # returns a chainable list of instances with only the mentioned fields.
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).ids
+    #   # returns an Array of ids, available since Rails 3.2.1.
+    #
+    #   Person.where(name: 'Spartacus', rating: 4).pluck(:field1, :field2)
+    #   # returns an Array of the required fields, available since Rails 3.1.
+    def find(*args)
+      if block_given?
+        to_a.find(*args) { |*block_args| yield(*block_args) }
+      else
+        find_with_ids(*args)
+      end
+    end
+
+    # Finds the first record matching the specified conditions. There
+    # is no implied ordering so if order matters, you should specify it
+    # yourself.
+    #
+    # If no record is found, returns <tt>nil</tt>.
+    #
+    #   Post.find_by name: 'Spartacus', rating: 4
+    #   Post.find_by "published_at < ?", 2.weeks.ago
+    def find_by(*args)
+      where(*args).take
+    end
+
+    # Like <tt>find_by</tt>, except that if no record is found, raises
+    # an <tt>ActiveRecord::RecordNotFound</tt> error.
+    def find_by!(*args)
+      where(*args).take!
+    end
+
+    # Gives a record (or N records if a parameter is supplied) without any implied
+    # order. The order will depend on the database implementation.
+    # If an order is supplied it will be respected.
+    #
+    #   Person.take # returns an object fetched by SELECT * FROM people LIMIT 1
+    #   Person.take(5) # returns 5 objects fetched by SELECT * FROM people LIMIT 5
+    #   Person.where(["name LIKE '%?'", name]).take
+    def take(limit = nil)
+      limit ? limit(limit).to_a : find_take
+    end
+
+    # Same as +take+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found. Note that <tt>take!</tt> accepts no arguments.
+    def take!
+      take or raise RecordNotFound
+    end
+
+    # Find the first record (or first N records if a parameter is supplied).
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.first # returns the first object fetched by SELECT * FROM people
+    #   Person.where(["user_name = ?", user_name]).first
+    #   Person.where(["user_name = :u", { u: user_name }]).first
+    #   Person.order("created_on DESC").offset(5).first
+    #   Person.first(3) # returns the first three objects fetched by SELECT * FROM people LIMIT 3
+    #
+    # ==== Rails 3
+    #
+    #   Person.first # SELECT "people".* FROM "people" LIMIT 1
+    #
+    # NOTE: Rails 3 may not order this query by the primary key and the order
+    # will depend on the database implementation. In order to ensure that behavior,
+    # use <tt>User.order(:id).first</tt> instead.
+    #
+    # ==== Rails 4
+    #
+    #   Person.first # SELECT "people".* FROM "people" ORDER BY "people"."id" ASC LIMIT 1
+    #
+    def first(limit = nil)
+      if limit
+        find_nth_with_limit(offset_index, limit)
+      else
+        find_nth(0, offset_index)
+      end
+    end
+
+    # Same as +first+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found. Note that <tt>first!</tt> accepts no arguments.
+    def first!
+      first or raise RecordNotFound
+    end
+
+    # Find the last record (or last N records if a parameter is supplied).
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.last # returns the last object fetched by SELECT * FROM people
+    #   Person.where(["user_name = ?", user_name]).last
+    #   Person.order("created_on DESC").offset(5).last
+    #   Person.last(3) # returns the last three objects fetched by SELECT * FROM people.
+    #
+    # Take note that in that last case, the results are sorted in ascending order:
+    #
+    #   [#<Person id:2>, #<Person id:3>, #<Person id:4>]
+    #
+    # and not:
+    #
+    #   [#<Person id:4>, #<Person id:3>, #<Person id:2>]
+    def last(limit = nil)
+      if limit
+        if order_values.empty? && primary_key
+          order(arel_table[primary_key].desc).limit(limit).reverse
+        else
+          to_a.last(limit)
+        end
+      else
+        find_last
+      end
+    end
+
+    # Same as +last+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found. Note that <tt>last!</tt> accepts no arguments.
+    def last!
+      last or raise RecordNotFound
+    end
+
+    # Find the second record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.second # returns the second object fetched by SELECT * FROM people
+    #   Person.offset(3).second # returns the second object from OFFSET 3 (which is OFFSET 4)
+    #   Person.where(["user_name = :u", { u: user_name }]).second
+    def second
+      find_nth(1, offset_index)
+    end
+
+    # Same as +second+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found.
+    def second!
+      second or raise RecordNotFound
+    end
+
+    # Find the third record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.third # returns the third object fetched by SELECT * FROM people
+    #   Person.offset(3).third # returns the third object from OFFSET 3 (which is OFFSET 5)
+    #   Person.where(["user_name = :u", { u: user_name }]).third
+    def third
+      find_nth(2, offset_index)
+    end
+
+    # Same as +third+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found.
+    def third!
+      third or raise RecordNotFound
+    end
+
+    # Find the fourth record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.fourth # returns the fourth object fetched by SELECT * FROM people
+    #   Person.offset(3).fourth # returns the fourth object from OFFSET 3 (which is OFFSET 6)
+    #   Person.where(["user_name = :u", { u: user_name }]).fourth
+    def fourth
+      find_nth(3, offset_index)
+    end
+
+    # Same as +fourth+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found.
+    def fourth!
+      fourth or raise RecordNotFound
+    end
+
+    # Find the fifth record.
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.fifth # returns the fifth object fetched by SELECT * FROM people
+    #   Person.offset(3).fifth # returns the fifth object from OFFSET 3 (which is OFFSET 7)
+    #   Person.where(["user_name = :u", { u: user_name }]).fifth
+    def fifth
+      find_nth(4, offset_index)
+    end
+
+    # Same as +fifth+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found.
+    def fifth!
+      fifth or raise RecordNotFound
+    end
+
+    # Find the forty-second record. Also known as accessing "the reddit".
+    # If no order is defined it will order by primary key.
+    #
+    #   Person.forty_two # returns the forty-second object fetched by SELECT * FROM people
+    #   Person.offset(3).forty_two # returns the forty-second object from OFFSET 3 (which is OFFSET 44)
+    #   Person.where(["user_name = :u", { u: user_name }]).forty_two
+    def forty_two
+      find_nth(41, offset_index)
+    end
+
+    # Same as +forty_two+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found.
+    def forty_two!
+      forty_two or raise RecordNotFound
+    end
+
+    # Returns +true+ if a record exists in the table that matches the +id+ or
+    # conditions given, or +false+ otherwise. The argument can take six forms:
+    #
+    # * Integer - Finds the record with this primary key.
+    # * String - Finds the record with a primary key corresponding to this
+    #   string (such as <tt>'5'</tt>).
+    # * Array - Finds the record that matches these +find+-style conditions
+    #   (such as <tt>['name LIKE ?', "%#{query}%"]</tt>).
+    # * Hash - Finds the record that matches these +find+-style conditions
+    #   (such as <tt>{name: 'David'}</tt>).
+    # * +false+ - Returns always +false+.
+    # * No args - Returns +false+ if the table is empty, +true+ otherwise.
+    #
+    # For more information about specifying conditions as a hash or array,
+    # see the Conditions section in the introduction to <tt>ActiveRecord::Base</tt>.
+    #
+    # Note: You can't pass in a condition as a string (like <tt>name =
+    # 'Jamie'</tt>), since it would be sanitized and then queried against
+    # the primary key column, like <tt>id = 'name = \'Jamie\''</tt>.
+    #
+    #   Person.exists?(5)
+    #   Person.exists?('5')
+    #   Person.exists?(['name LIKE ?', "%#{query}%"])
+    #   Person.exists?(id: [1, 4, 8])
+    #   Person.exists?(name: 'David')
+    #   Person.exists?(false)
+    #   Person.exists?
+    def exists?(conditions = :none)
+      if Base === conditions
+        conditions = conditions.id
+        ActiveSupport::Deprecation.warn "You are passing an instance of ActiveRecord::Base to `exists?`." \
+          "Please pass the id of the object by calling `.id`"
+      end
+
+      return false if !conditions
+
+      relation = apply_join_dependency(self, construct_join_dependency)
+      return false if ActiveRecord::NullRelation === relation
+
+      relation = relation.except(:select, :order).select(ONE_AS_ONE).limit(1)
+
+      case conditions
+      when Array, Hash
+        relation = relation.where(conditions)
+      else
+        unless conditions == :none
+          relation = where(primary_key => conditions)
+        end
+      end
+
+      connection.select_value(relation, "#{name} Exists", relation.bind_values) ? true : false
+    end
+
+    # This method is called whenever no records are found with either a single
+    # id or multiple ids and raises a +ActiveRecord::RecordNotFound+ exception.
+    #
+    # The error message is different depending on whether a single id or
+    # multiple ids are provided. If multiple ids are provided, then the number
+    # of results obtained should be provided in the +result_size+ argument and
+    # the expected number of results should be provided in the +expected_size+
+    # argument.
+    def raise_record_not_found_exception!(ids, result_size, expected_size) #:nodoc:
+      conditions = arel.where_sql
+      conditions = " [#{conditions}]" if conditions
+
+      if Array(ids).size == 1
+        error = "Couldn't find #{@klass.name} with '#{primary_key}'=#{ids}#{conditions}"
+      else
+        error = "Couldn't find all #{@klass.name.pluralize} with '#{primary_key}': "
+        error << "(#{ids.join(", ")})#{conditions} (found #{result_size} results, but was looking for #{expected_size})"
+      end
+
+      raise RecordNotFound, error
+    end
+
+    private
+
+    def offset_index
+      offset_value || 0
+    end
+
+    def find_with_associations
+      # NOTE: the JoinDependency constructed here needs to know about
+      #       any joins already present in `self`, so pass them in
+      #
+      # failing to do so means that in cases like activerecord/test/cases/associations/inner_join_association_test.rb:136
+      # incorrect SQL is generated. In that case, the join dependency for
+      # SpecialCategorizations is constructed without knowledge of the
+      # preexisting join in joins_values to categorizations (by way of
+      # the `has_many :through` for categories).
+      #
+      join_dependency = construct_join_dependency(joins_values)
+
+      aliases  = join_dependency.aliases
+      relation = select aliases.columns
+      relation = apply_join_dependency(relation, join_dependency)
+
+      if block_given?
+        yield relation
+      else
+        if ActiveRecord::NullRelation === relation
+          []
+        else
+          arel = relation.arel
+          rows = connection.select_all(arel, 'SQL', arel.bind_values + relation.bind_values)
+          join_dependency.instantiate(rows, aliases)
+        end
+      end
+    end
+
+    def construct_join_dependency(joins = [])
+      including = eager_load_values + includes_values
+      ActiveRecord::Associations::JoinDependency.new(@klass, including, joins)
+    end
+
+    def construct_relation_for_association_calculations
+      from = arel.froms.first
+      if Arel::Table === from
+        apply_join_dependency(self, construct_join_dependency)
+      else
+        # FIXME: as far as I can tell, `from` will always be an Arel::Table.
+        # There are no tests that test this branch, but presumably it's
+        # possible for `from` to be a list?
+        apply_join_dependency(self, construct_join_dependency(from))
+      end
+    end
+
+    def apply_join_dependency(relation, join_dependency)
+      relation = relation.except(:includes, :eager_load, :preload)
+      relation = relation.joins join_dependency
+
+      if using_limitable_reflections?(join_dependency.reflections)
+        relation
+      else
+        if relation.limit_value
+          limited_ids = limited_ids_for(relation)
+          limited_ids.empty? ? relation.none! : relation.where!(table[primary_key].in(limited_ids))
+        end
+        relation.except(:limit, :offset)
+      end
+    end
+
+    def limited_ids_for(relation)
+      values = @klass.connection.columns_for_distinct(
+        "#{quoted_table_name}.#{quoted_primary_key}", relation.order_values)
+
+      relation = relation.except(:select).select(values).distinct!
+
+      id_rows = @klass.connection.select_all(relation.arel, 'SQL', relation.bind_values)
+      id_rows.map {|row| row[primary_key]}
+    end
+
+    def using_limitable_reflections?(reflections)
+      reflections.none? { |r| r.collection? }
+    end
+
+    protected
+
+    def find_with_ids(*ids)
+      raise UnknownPrimaryKey.new(@klass) if primary_key.nil?
+
+      expects_array = ids.first.kind_of?(Array)
+      return ids.first if expects_array && ids.first.empty?
+
+      ids = ids.flatten.compact.uniq
+
+      case ids.size
+      when 0
+        raise RecordNotFound, "Couldn't find #{@klass.name} without an ID"
+      when 1
+        result = find_one(ids.first)
+        expects_array ? [ result ] : result
+      else
+        find_some(ids)
+      end
+    end
+
+    def find_one(id)
+      if ActiveRecord::Base === id
+        id = id.id
+        ActiveSupport::Deprecation.warn "You are passing an instance of ActiveRecord::Base to `find`." \
+          "Please pass the id of the object by calling `.id`"
+      end
+
+      column = columns_hash[primary_key]
+      substitute = connection.substitute_at(column, bind_values.length)
+      relation = where(table[primary_key].eq(substitute))
+      relation.bind_values += [[column, id]]
+      record = relation.take
+
+      raise_record_not_found_exception!(id, 0, 1) unless record
+
+      record
+    end
+
+    def find_some(ids)
+      result = where(table[primary_key].in(ids)).to_a
+
+      expected_size =
+        if limit_value && ids.size > limit_value
+          limit_value
+        else
+          ids.size
+        end
+
+      # 11 ids with limit 3, offset 9 should give 2 results.
+      if offset_value && (ids.size - offset_value < expected_size)
+        expected_size = ids.size - offset_value
+      end
+
+      if result.size == expected_size
+        result
+      else
+        raise_record_not_found_exception!(ids, result.size, expected_size)
+      end
+    end
+
+    def find_take
+      if loaded?
+        @records.first
+      else
+        @take ||= limit(1).to_a.first
+      end
+    end
+
+    def find_nth(index, offset)
+      if loaded?
+        @records[index]
+      else
+        offset += index
+        @offsets[offset] ||= find_nth_with_limit(offset, 1).first
+      end
+    end
+
+    def find_nth_with_limit(offset, limit)
+      relation = if order_values.empty? && primary_key
+                   order(arel_table[primary_key].asc)
+                 else
+                   self
+                 end
+
+      relation = relation.offset(offset) unless offset.zero?
+      relation.limit(limit).to_a
+    end
+
+    def find_last
+      if loaded?
+        @records.last
+      else
+        @last ||=
+          if limit_value
+            to_a.last
+          else
+            reverse_order.limit(1).to_a.first
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb
new file mode 100644
index 0000000000..ac41d0aa80
--- /dev/null
+++ b/activerecord/lib/active_record/relation/merger.rb
@@ -0,0 +1,182 @@
+require 'active_support/core_ext/hash/keys'
+require "set"
+
+module ActiveRecord
+  class Relation
+    class HashMerger # :nodoc:
+      attr_reader :relation, :hash
+
+      def initialize(relation, hash)
+        hash.assert_valid_keys(*Relation::VALUE_METHODS)
+
+        @relation = relation
+        @hash     = hash
+      end
+
+      def merge
+        Merger.new(relation, other).merge
+      end
+
+      # Applying values to a relation has some side effects. E.g.
+      # interpolation might take place for where values. So we should
+      # build a relation to merge in rather than directly merging
+      # the values.
+      def other
+        other = Relation.create(relation.klass, relation.table)
+        hash.each { |k, v|
+          if k == :joins
+            if Hash === v
+              other.joins!(v)
+            else
+              other.joins!(*v)
+            end
+          elsif k == :select
+            other._select!(v)
+          else
+            other.send("#{k}!", v)
+          end
+        }
+        other
+      end
+    end
+
+    class Merger # :nodoc:
+      attr_reader :relation, :values, :other
+
+      def initialize(relation, other)
+        @relation = relation
+        @values   = other.values
+        @other    = other
+      end
+
+      NORMAL_VALUES = Relation::SINGLE_VALUE_METHODS +
+                      Relation::MULTI_VALUE_METHODS -
+                      [:joins, :where, :order, :bind, :reverse_order, :lock, :create_with, :reordering, :from] # :nodoc:
+
+      def normal_values
+        NORMAL_VALUES
+      end
+
+      def merge
+        normal_values.each do |name|
+          value = values[name]
+          # The unless clause is here mostly for performance reasons (since the `send` call might be moderately
+          # expensive), most of the time the value is going to be `nil` or `.blank?`, the only catch is that
+          # `false.blank?` returns `true`, so there needs to be an extra check so that explicit `false` values
+          # don't fall through the cracks.
+          unless value.nil? || (value.blank? && false != value)
+            if name == :select
+              relation._select!(*value)
+            else
+              relation.send("#{name}!", *value)
+            end
+          end
+        end
+
+        merge_multi_values
+        merge_single_values
+        merge_joins
+
+        relation
+      end
+
+      private
+
+      def merge_joins
+        return if values[:joins].blank?
+
+        if other.klass == relation.klass
+          relation.joins!(*values[:joins])
+        else
+          joins_dependency, rest = values[:joins].partition do |join|
+            case join
+            when Hash, Symbol, Array
+              true
+            else
+              false
+            end
+          end
+
+          join_dependency = ActiveRecord::Associations::JoinDependency.new(other.klass,
+                                                                           joins_dependency,
+                                                                           [])
+          relation.joins! rest
+
+          @relation = relation.joins join_dependency
+        end
+      end
+
+      def merge_multi_values
+        lhs_wheres = relation.where_values
+        rhs_wheres = values[:where] || []
+
+        lhs_binds  = relation.bind_values
+        rhs_binds  = values[:bind] || []
+
+        removed, kept = partition_overwrites(lhs_wheres, rhs_wheres)
+
+        where_values = kept + rhs_wheres
+        bind_values  = filter_binds(lhs_binds, removed) + rhs_binds
+
+        conn = relation.klass.connection
+        bv_index = 0
+        where_values.map! do |node|
+          if Arel::Nodes::Equality === node && Arel::Nodes::BindParam === node.right
+            substitute = conn.substitute_at(bind_values[bv_index].first, bv_index)
+            bv_index += 1
+            Arel::Nodes::Equality.new(node.left, substitute)
+          else
+            node
+          end
+        end
+
+        relation.where_values = where_values
+        relation.bind_values  = bind_values
+
+        if values[:reordering]
+          # override any order specified in the original relation
+          relation.reorder! values[:order]
+        elsif values[:order]
+          # merge in order_values from relation
+          relation.order! values[:order]
+        end
+
+        relation.extend(*values[:extending]) unless values[:extending].blank?
+      end
+
+      def merge_single_values
+        relation.from_value          = values[:from] unless relation.from_value
+        relation.lock_value          = values[:lock] unless relation.lock_value
+
+        unless values[:create_with].blank?
+          relation.create_with_value = (relation.create_with_value || {}).merge(values[:create_with])
+        end
+      end
+
+      def filter_binds(lhs_binds, removed_wheres)
+        return lhs_binds if removed_wheres.empty?
+
+        set = Set.new removed_wheres.map { |x| x.left.name.to_s }
+        lhs_binds.dup.delete_if { |col,_| set.include? col.name }
+      end
+
+      # Remove equalities from the existing relation with a LHS which is
+      # present in the relation being merged in.
+      # returns [things_to_remove, things_to_keep]
+      def partition_overwrites(lhs_wheres, rhs_wheres)
+        if lhs_wheres.empty? || rhs_wheres.empty?
+          return [[], lhs_wheres]
+        end
+
+        nodes = rhs_wheres.find_all do |w|
+          w.respond_to?(:operator) && w.operator == :==
+        end
+        seen = Set.new(nodes) { |node| node.left }
+
+        lhs_wheres.partition do |w|
+          w.respond_to?(:operator) && w.operator == :== && seen.include?(w.left)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
new file mode 100644
index 0000000000..eff5c8f09c
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -0,0 +1,126 @@
+module ActiveRecord
+  class PredicateBuilder # :nodoc:
+    @handlers = []
+
+    autoload :RelationHandler, 'active_record/relation/predicate_builder/relation_handler'
+    autoload :ArrayHandler, 'active_record/relation/predicate_builder/array_handler'
+
+    def self.resolve_column_aliases(klass, hash)
+      hash = hash.dup
+      hash.keys.grep(Symbol) do |key|
+        if klass.attribute_alias? key
+          hash[klass.attribute_alias(key)] = hash.delete key
+        end
+      end
+      hash
+    end
+
+    def self.build_from_hash(klass, attributes, default_table)
+      queries = []
+
+      attributes.each do |column, value|
+        table = default_table
+
+        if value.is_a?(Hash)
+          if value.empty?
+            queries << '1=0'
+          else
+            table       = Arel::Table.new(column, default_table.engine)
+            association = klass._reflect_on_association(column.to_sym)
+
+            value.each do |k, v|
+              queries.concat expand(association && association.klass, table, k, v)
+            end
+          end
+        else
+          column = column.to_s
+
+          if column.include?('.')
+            table_name, column = column.split('.', 2)
+            table = Arel::Table.new(table_name, default_table.engine)
+          end
+
+          queries.concat expand(klass, table, column, value)
+        end
+      end
+
+      queries
+    end
+
+    def self.expand(klass, table, column, value)
+      queries = []
+
+      # Find the foreign key when using queries such as:
+      # Post.where(author: author)
+      #
+      # For polymorphic relationships, find the foreign key and type:
+      # PriceEstimate.where(estimate_of: treasure)
+      if klass && reflection = klass._reflect_on_association(column.to_sym)
+        if reflection.polymorphic? && base_class = polymorphic_base_class_from_value(value)
+          queries << build(table[reflection.foreign_type], base_class)
+        end
+
+        column = reflection.foreign_key
+      end
+
+      queries << build(table[column], value)
+      queries
+    end
+
+    def self.polymorphic_base_class_from_value(value)
+      case value
+      when Relation
+        value.klass.base_class
+      when Array
+        val = value.compact.first
+        val.class.base_class if val.is_a?(Base)
+      when Base
+        value.class.base_class
+      end
+    end
+
+    def self.references(attributes)
+      attributes.map do |key, value|
+        if value.is_a?(Hash)
+          key
+        else
+          key = key.to_s
+          key.split('.').first if key.include?('.')
+        end
+      end.compact
+    end
+
+    # Define how a class is converted to Arel nodes when passed to +where+.
+    # The handler can be any object that responds to +call+, and will be used
+    # for any value that +===+ the class given. For example:
+    #
+    #     MyCustomDateRange = Struct.new(:start, :end)
+    #     handler = proc do |column, range|
+    #       Arel::Nodes::Between.new(column,
+    #         Arel::Nodes::And.new([range.start, range.end])
+    #       )
+    #     end
+    #     ActiveRecord::PredicateBuilder.register_handler(MyCustomDateRange, handler)
+    def self.register_handler(klass, handler)
+      @handlers.unshift([klass, handler])
+    end
+
+    register_handler(BasicObject, ->(attribute, value) { attribute.eq(value) })
+    # FIXME: I think we need to deprecate this behavior
+    register_handler(Class, ->(attribute, value) { attribute.eq(value.name) })
+    register_handler(Base, ->(attribute, value) { attribute.eq(value.id) })
+    register_handler(Range, ->(attribute, value) { attribute.in(value) })
+    register_handler(Relation, RelationHandler.new)
+    register_handler(Array, ArrayHandler.new)
+
+    def self.build(attribute, value)
+      handler_for(value).call(attribute, value)
+    end
+    private_class_method :build
+
+    def self.handler_for(object)
+      @handlers.detect { |klass, _| klass === object }.last
+    end
+    private_class_method :handler_for
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder/array_handler.rb b/activerecord/lib/active_record/relation/predicate_builder/array_handler.rb
new file mode 100644
index 0000000000..78dba8be06
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/array_handler.rb
@@ -0,0 +1,34 @@
+module ActiveRecord
+  class PredicateBuilder
+    class ArrayHandler # :nodoc:
+      def call(attribute, value)
+        return attribute.in([]) if value.empty?
+
+        values = value.map { |x| x.is_a?(Base) ? x.id : x }
+        ranges, values = values.partition { |v| v.is_a?(Range) }
+        nils, values = values.partition(&:nil?)
+
+        values_predicate =
+          case values.length
+          when 0 then NullPredicate
+          when 1 then attribute.eq(values.first)
+          else attribute.in(values)
+          end
+
+        unless nils.empty?
+          values_predicate = values_predicate.or(attribute.eq(nil))
+        end
+
+        array_predicates = ranges.map { |range| attribute.in(range) }
+        array_predicates << values_predicate
+        array_predicates.inject { |composite, predicate| composite.or(predicate) }
+      end
+
+      module NullPredicate
+        def self.or(other)
+          other
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/predicate_builder/relation_handler.rb b/activerecord/lib/active_record/relation/predicate_builder/relation_handler.rb
new file mode 100644
index 0000000000..618fa3cdd9
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/relation_handler.rb
@@ -0,0 +1,13 @@
+module ActiveRecord
+  class PredicateBuilder
+    class RelationHandler # :nodoc:
+      def call(attribute, value)
+        if value.select_values.empty?
+          value = value.select(value.klass.arel_table[value.klass.primary_key])
+        end
+
+        attribute.in(value.arel.ast)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
new file mode 100644
index 0000000000..1262b2c291
--- /dev/null
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -0,0 +1,1141 @@
+require 'active_support/core_ext/array/wrap'
+
+module ActiveRecord
+  module QueryMethods
+    extend ActiveSupport::Concern
+
+    # WhereChain objects act as placeholder for queries in which #where does not have any parameter.
+    # In this case, #where must be chained with #not to return a new relation.
+    class WhereChain
+      def initialize(scope)
+        @scope = scope
+      end
+
+      # Returns a new relation expressing WHERE + NOT condition according to
+      # the conditions in the arguments.
+      #
+      # +not+ accepts conditions as a string, array, or hash. See #where for
+      # more details on each format.
+      #
+      #    User.where.not("name = 'Jon'")
+      #    # SELECT * FROM users WHERE NOT (name = 'Jon')
+      #
+      #    User.where.not(["name = ?", "Jon"])
+      #    # SELECT * FROM users WHERE NOT (name = 'Jon')
+      #
+      #    User.where.not(name: "Jon")
+      #    # SELECT * FROM users WHERE name != 'Jon'
+      #
+      #    User.where.not(name: nil)
+      #    # SELECT * FROM users WHERE name IS NOT NULL
+      #
+      #    User.where.not(name: %w(Ko1 Nobu))
+      #    # SELECT * FROM users WHERE name NOT IN ('Ko1', 'Nobu')
+      #
+      #    User.where.not(name: "Jon", role: "admin")
+      #    # SELECT * FROM users WHERE name != 'Jon' AND role != 'admin'
+      def not(opts, *rest)
+        where_value = @scope.send(:build_where, opts, rest).map do |rel|
+          case rel
+          when NilClass
+            raise ArgumentError, 'Invalid argument for .where.not(), got nil.'
+          when Arel::Nodes::In
+            Arel::Nodes::NotIn.new(rel.left, rel.right)
+          when Arel::Nodes::Equality
+            Arel::Nodes::NotEqual.new(rel.left, rel.right)
+          when String
+            Arel::Nodes::Not.new(Arel::Nodes::SqlLiteral.new(rel))
+          else
+            Arel::Nodes::Not.new(rel)
+          end
+        end
+
+        @scope.references!(PredicateBuilder.references(opts)) if Hash === opts
+        @scope.where_values += where_value
+        @scope
+      end
+    end
+
+    Relation::MULTI_VALUE_METHODS.each do |name|
+      class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name}_values                   # def select_values
+          @values[:#{name}] || []            #   @values[:select] || []
+        end                                  # end
+                                             #
+        def #{name}_values=(values)          # def select_values=(values)
+          raise ImmutableRelation if @loaded #   raise ImmutableRelation if @loaded
+          check_cached_relation
+          @values[:#{name}] = values         #   @values[:select] = values
+        end                                  # end
+      CODE
+    end
+
+    (Relation::SINGLE_VALUE_METHODS - [:create_with]).each do |name|
+      class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name}_value                    # def readonly_value
+          @values[:#{name}]                  #   @values[:readonly]
+        end                                  # end
+      CODE
+    end
+
+    Relation::SINGLE_VALUE_METHODS.each do |name|
+      class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def #{name}_value=(value)            # def readonly_value=(value)
+          raise ImmutableRelation if @loaded #   raise ImmutableRelation if @loaded
+          check_cached_relation
+          @values[:#{name}] = value          #   @values[:readonly] = value
+        end                                  # end
+      CODE
+    end
+
+    def check_cached_relation # :nodoc:
+      if defined?(@arel) && @arel
+        @arel = nil
+        ActiveSupport::Deprecation.warn <<-WARNING
+Modifying already cached Relation. The cache will be reset.
+Use a cloned Relation to prevent this warning.
+WARNING
+      end
+    end
+
+    def create_with_value # :nodoc:
+      @values[:create_with] || {}
+    end
+
+    alias extensions extending_values
+
+    # Specify relationships to be included in the result set. For
+    # example:
+    #
+    #   users = User.includes(:address)
+    #   users.each do |user|
+    #     user.address.city
+    #   end
+    #
+    # allows you to access the +address+ attribute of the +User+ model without
+    # firing an additional query. This will often result in a
+    # performance improvement over a simple +join+.
+    #
+    # You can also specify multiple relationships, like this:
+    #
+    #   users = User.includes(:address, :friends)
+    #
+    # Loading nested relationships is possible using a Hash:
+    #
+    #   users = User.includes(:address, friends: [:address, :followers])
+    #
+    # === conditions
+    #
+    # If you want to add conditions to your included models you'll have
+    # to explicitly reference them. For example:
+    #
+    #   User.includes(:posts).where('posts.name = ?', 'example')
+    #
+    # Will throw an error, but this will work:
+    #
+    #   User.includes(:posts).where('posts.name = ?', 'example').references(:posts)
+    #
+    # Note that +includes+ works with association names while +references+ needs
+    # the actual table name.
+    def includes(*args)
+      check_if_method_has_arguments!(:includes, args)
+      spawn.includes!(*args)
+    end
+
+    def includes!(*args) # :nodoc:
+      args.reject!(&:blank?)
+      args.flatten!
+
+      self.includes_values |= args
+      self
+    end
+
+    # Forces eager loading by performing a LEFT OUTER JOIN on +args+:
+    #
+    #   User.eager_load(:posts)
+    #   => SELECT "users"."id" AS t0_r0, "users"."name" AS t0_r1, ...
+    #   FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" =
+    #   "users"."id"
+    def eager_load(*args)
+      check_if_method_has_arguments!(:eager_load, args)
+      spawn.eager_load!(*args)
+    end
+
+    def eager_load!(*args) # :nodoc:
+      self.eager_load_values += args
+      self
+    end
+
+    # Allows preloading of +args+, in the same way that +includes+ does:
+    #
+    #   User.preload(:posts)
+    #   => SELECT "posts".* FROM "posts" WHERE "posts"."user_id" IN (1, 2, 3)
+    def preload(*args)
+      check_if_method_has_arguments!(:preload, args)
+      spawn.preload!(*args)
+    end
+
+    def preload!(*args) # :nodoc:
+      self.preload_values += args
+      self
+    end
+
+    # Use to indicate that the given +table_names+ are referenced by an SQL string,
+    # and should therefore be JOINed in any query rather than loaded separately.
+    # This method only works in conjunction with +includes+.
+    # See #includes for more details.
+    #
+    #   User.includes(:posts).where("posts.name = 'foo'")
+    #   # => Doesn't JOIN the posts table, resulting in an error.
+    #
+    #   User.includes(:posts).where("posts.name = 'foo'").references(:posts)
+    #   # => Query now knows the string references posts, so adds a JOIN
+    def references(*table_names)
+      check_if_method_has_arguments!(:references, table_names)
+      spawn.references!(*table_names)
+    end
+
+    def references!(*table_names) # :nodoc:
+      table_names.flatten!
+      table_names.map!(&:to_s)
+
+      self.references_values |= table_names
+      self
+    end
+
+    # Works in two unique ways.
+    #
+    # First: takes a block so it can be used just like Array#select.
+    #
+    #   Model.all.select { |m| m.field == value }
+    #
+    # This will build an array of objects from the database for the scope,
+    # converting them into an array and iterating through them using Array#select.
+    #
+    # Second: Modifies the SELECT statement for the query so that only certain
+    # fields are retrieved:
+    #
+    #   Model.select(:field)
+    #   # => [#<Model id: nil, field: "value">]
+    #
+    # Although in the above example it looks as though this method returns an
+    # array, it actually returns a relation object and can have other query
+    # methods appended to it, such as the other methods in ActiveRecord::QueryMethods.
+    #
+    # The argument to the method can also be an array of fields.
+    #
+    #   Model.select(:field, :other_field, :and_one_more)
+    #   # => [#<Model id: nil, field: "value", other_field: "value", and_one_more: "value">]
+    #
+    # You can also use one or more strings, which will be used unchanged as SELECT fields.
+    #
+    #   Model.select('field AS field_one', 'other_field AS field_two')
+    #   # => [#<Model id: nil, field: "value", other_field: "value">]
+    #
+    # If an alias was specified, it will be accessible from the resulting objects:
+    #
+    #   Model.select('field AS field_one').first.field_one
+    #   # => "value"
+    #
+    # Accessing attributes of an object that do not have fields retrieved by a select
+    # except +id+ will throw <tt>ActiveModel::MissingAttributeError</tt>:
+    #
+    #   Model.select(:field).first.other_field
+    #   # => ActiveModel::MissingAttributeError: missing attribute: other_field
+    def select(*fields)
+      if block_given?
+        to_a.select { |*block_args| yield(*block_args) }
+      else
+        raise ArgumentError, 'Call this with at least one field' if fields.empty?
+        spawn._select!(*fields)
+      end
+    end
+
+    def _select!(*fields) # :nodoc:
+      fields.flatten!
+      fields.map! do |field|
+        klass.attribute_alias?(field) ? klass.attribute_alias(field) : field
+      end
+      self.select_values += fields
+      self
+    end
+
+    # Allows to specify a group attribute:
+    #
+    #   User.group(:name)
+    #   => SELECT "users".* FROM "users" GROUP BY name
+    #
+    # Returns an array with distinct records based on the +group+ attribute:
+    #
+    #   User.select([:id, :name])
+    #   => [#<User id: 1, name: "Oscar">, #<User id: 2, name: "Oscar">, #<User id: 3, name: "Foo">
+    #
+    #   User.group(:name)
+    #   => [#<User id: 3, name: "Foo", ...>, #<User id: 2, name: "Oscar", ...>]
+    #
+    #   User.group('name AS grouped_name, age')
+    #   => [#<User id: 3, name: "Foo", age: 21, ...>, #<User id: 2, name: "Oscar", age: 21, ...>, #<User id: 5, name: "Foo", age: 23, ...>]
+    #
+    # Passing in an array of attributes to group by is also supported.
+    #   User.select([:id, :first_name]).group(:id, :first_name).first(3)
+    #   => [#<User id: 1, first_name: "Bill">, #<User id: 2, first_name: "Earl">, #<User id: 3, first_name: "Beto">]
+    def group(*args)
+      check_if_method_has_arguments!(:group, args)
+      spawn.group!(*args)
+    end
+
+    def group!(*args) # :nodoc:
+      args.flatten!
+
+      self.group_values += args
+      self
+    end
+
+    # Allows to specify an order attribute:
+    #
+    #   User.order(:name)
+    #   => SELECT "users".* FROM "users" ORDER BY "users"."name" ASC
+    #
+    #   User.order(email: :desc)
+    #   => SELECT "users".* FROM "users" ORDER BY "users"."email" DESC
+    #
+    #   User.order(:name, email: :desc)
+    #   => SELECT "users".* FROM "users" ORDER BY "users"."name" ASC, "users"."email" DESC
+    #
+    #   User.order('name')
+    #   => SELECT "users".* FROM "users" ORDER BY name
+    #
+    #   User.order('name DESC')
+    #   => SELECT "users".* FROM "users" ORDER BY name DESC
+    #
+    #   User.order('name DESC, email')
+    #   => SELECT "users".* FROM "users" ORDER BY name DESC, email
+    def order(*args)
+      check_if_method_has_arguments!(:order, args)
+      spawn.order!(*args)
+    end
+
+    def order!(*args) # :nodoc:
+      preprocess_order_args(args)
+
+      self.order_values += args
+      self
+    end
+
+    # Replaces any existing order defined on the relation with the specified order.
+    #
+    #   User.order('email DESC').reorder('id ASC') # generated SQL has 'ORDER BY id ASC'
+    #
+    # Subsequent calls to order on the same relation will be appended. For example:
+    #
+    #   User.order('email DESC').reorder('id ASC').order('name ASC')
+    #
+    # generates a query with 'ORDER BY id ASC, name ASC'.
+    def reorder(*args)
+      check_if_method_has_arguments!(:reorder, args)
+      spawn.reorder!(*args)
+    end
+
+    def reorder!(*args) # :nodoc:
+      preprocess_order_args(args)
+
+      self.reordering_value = true
+      self.order_values = args
+      self
+    end
+
+    VALID_UNSCOPING_VALUES = Set.new([:where, :select, :group, :order, :lock,
+                                     :limit, :offset, :joins, :includes, :from,
+                                     :readonly, :having])
+
+    # Removes an unwanted relation that is already defined on a chain of relations.
+    # This is useful when passing around chains of relations and would like to
+    # modify the relations without reconstructing the entire chain.
+    #
+    #   User.order('email DESC').unscope(:order) == User.all
+    #
+    # The method arguments are symbols which correspond to the names of the methods
+    # which should be unscoped. The valid arguments are given in VALID_UNSCOPING_VALUES.
+    # The method can also be called with multiple arguments. For example:
+    #
+    #   User.order('email DESC').select('id').where(name: "John")
+    #       .unscope(:order, :select, :where) == User.all
+    #
+    # One can additionally pass a hash as an argument to unscope specific :where values.
+    # This is done by passing a hash with a single key-value pair. The key should be
+    # :where and the value should be the where value to unscope. For example:
+    #
+    #   User.where(name: "John", active: true).unscope(where: :name)
+    #       == User.where(active: true)
+    #
+    # This method is similar to <tt>except</tt>, but unlike
+    # <tt>except</tt>, it persists across merges:
+    #
+    #   User.order('email').merge(User.except(:order))
+    #       == User.order('email')
+    #
+    #   User.order('email').merge(User.unscope(:order))
+    #       == User.all
+    #
+    # This means it can be used in association definitions:
+    #
+    #   has_many :comments, -> { unscope where: :trashed }
+    #
+    def unscope(*args)
+      check_if_method_has_arguments!(:unscope, args)
+      spawn.unscope!(*args)
+    end
+
+    def unscope!(*args) # :nodoc:
+      args.flatten!
+      self.unscope_values += args
+
+      args.each do |scope|
+        case scope
+        when Symbol
+          symbol_unscoping(scope)
+        when Hash
+          scope.each do |key, target_value|
+            if key != :where
+              raise ArgumentError, "Hash arguments in .unscope(*args) must have :where as the key."
+            end
+
+            Array(target_value).each do |val|
+              where_unscoping(val)
+            end
+          end
+        else
+          raise ArgumentError, "Unrecognized scoping: #{args.inspect}. Use .unscope(where: :attribute_name) or .unscope(:order), for example."
+        end
+      end
+
+      self
+    end
+
+    # Performs a joins on +args+:
+    #
+    #   User.joins(:posts)
+    #   => SELECT "users".* FROM "users" INNER JOIN "posts" ON "posts"."user_id" = "users"."id"
+    #
+    # You can use strings in order to customize your joins:
+    #
+    #   User.joins("LEFT JOIN bookmarks ON bookmarks.bookmarkable_type = 'Post' AND bookmarks.user_id = users.id")
+    #   => SELECT "users".* FROM "users" LEFT JOIN bookmarks ON bookmarks.bookmarkable_type = 'Post' AND bookmarks.user_id = users.id
+    def joins(*args)
+      check_if_method_has_arguments!(:joins, args)
+
+      args.compact!
+      args.flatten!
+
+      spawn.joins!(*args)
+    end
+
+    def joins!(*args) # :nodoc:
+      self.joins_values += args
+      self
+    end
+
+    def bind(value)
+      spawn.bind!(value)
+    end
+
+    def bind!(value) # :nodoc:
+      self.bind_values += [value]
+      self
+    end
+
+    # Returns a new relation, which is the result of filtering the current relation
+    # according to the conditions in the arguments.
+    #
+    # #where accepts conditions in one of several formats. In the examples below, the resulting
+    # SQL is given as an illustration; the actual query generated may be different depending
+    # on the database adapter.
+    #
+    # === string
+    #
+    # A single string, without additional arguments, is passed to the query
+    # constructor as an SQL fragment, and used in the where clause of the query.
+    #
+    #    Client.where("orders_count = '2'")
+    #    # SELECT * from clients where orders_count = '2';
+    #
+    # Note that building your own string from user input may expose your application
+    # to injection attacks if not done properly. As an alternative, it is recommended
+    # to use one of the following methods.
+    #
+    # === array
+    #
+    # If an array is passed, then the first element of the array is treated as a template, and
+    # the remaining elements are inserted into the template to generate the condition.
+    # Active Record takes care of building the query to avoid injection attacks, and will
+    # convert from the ruby type to the database type where needed. Elements are inserted
+    # into the string in the order in which they appear.
+    #
+    #   User.where(["name = ? and email = ?", "Joe", "joe@example.com"])
+    #   # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com';
+    #
+    # Alternatively, you can use named placeholders in the template, and pass a hash as the
+    # second element of the array. The names in the template are replaced with the corresponding
+    # values from the hash.
+    #
+    #   User.where(["name = :name and email = :email", { name: "Joe", email: "joe@example.com" }])
+    #   # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com';
+    #
+    # This can make for more readable code in complex queries.
+    #
+    # Lastly, you can use sprintf-style % escapes in the template. This works slightly differently
+    # than the previous methods; you are responsible for ensuring that the values in the template
+    # are properly quoted. The values are passed to the connector for quoting, but the caller
+    # is responsible for ensuring they are enclosed in quotes in the resulting SQL. After quoting,
+    # the values are inserted using the same escapes as the Ruby core method <tt>Kernel::sprintf</tt>.
+    #
+    #   User.where(["name = '%s' and email = '%s'", "Joe", "joe@example.com"])
+    #   # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com';
+    #
+    # If #where is called with multiple arguments, these are treated as if they were passed as
+    # the elements of a single array.
+    #
+    #   User.where("name = :name and email = :email", { name: "Joe", email: "joe@example.com" })
+    #   # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com';
+    #
+    # When using strings to specify conditions, you can use any operator available from
+    # the database. While this provides the most flexibility, you can also unintentionally introduce
+    # dependencies on the underlying database. If your code is intended for general consumption,
+    # test with multiple database backends.
+    #
+    # === hash
+    #
+    # #where will also accept a hash condition, in which the keys are fields and the values
+    # are values to be searched for.
+    #
+    # Fields can be symbols or strings. Values can be single values, arrays, or ranges.
+    #
+    #    User.where({ name: "Joe", email: "joe@example.com" })
+    #    # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com'
+    #
+    #    User.where({ name: ["Alice", "Bob"]})
+    #    # SELECT * FROM users WHERE name IN ('Alice', 'Bob')
+    #
+    #    User.where({ created_at: (Time.now.midnight - 1.day)..Time.now.midnight })
+    #    # SELECT * FROM users WHERE (created_at BETWEEN '2012-06-09 07:00:00.000000' AND '2012-06-10 07:00:00.000000')
+    #
+    # In the case of a belongs_to relationship, an association key can be used
+    # to specify the model if an ActiveRecord object is used as the value.
+    #
+    #    author = Author.find(1)
+    #
+    #    # The following queries will be equivalent:
+    #    Post.where(author: author)
+    #    Post.where(author_id: author)
+    #
+    # This also works with polymorphic belongs_to relationships:
+    #
+    #    treasure = Treasure.create(name: 'gold coins')
+    #    treasure.price_estimates << PriceEstimate.create(price: 125)
+    #
+    #    # The following queries will be equivalent:
+    #    PriceEstimate.where(estimate_of: treasure)
+    #    PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: treasure)
+    #
+    # === Joins
+    #
+    # If the relation is the result of a join, you may create a condition which uses any of the
+    # tables in the join. For string and array conditions, use the table name in the condition.
+    #
+    #    User.joins(:posts).where("posts.created_at < ?", Time.now)
+    #
+    # For hash conditions, you can either use the table name in the key, or use a sub-hash.
+    #
+    #    User.joins(:posts).where({ "posts.published" => true })
+    #    User.joins(:posts).where({ posts: { published: true } })
+    #
+    # === no argument
+    #
+    # If no argument is passed, #where returns a new instance of WhereChain, that
+    # can be chained with #not to return a new relation that negates the where clause.
+    #
+    #    User.where.not(name: "Jon")
+    #    # SELECT * FROM users WHERE name != 'Jon'
+    #
+    # See WhereChain for more details on #not.
+    #
+    # === blank condition
+    #
+    # If the condition is any blank-ish object, then #where is a no-op and returns
+    # the current relation.
+    def where(opts = :chain, *rest)
+      if opts == :chain
+        WhereChain.new(spawn)
+      elsif opts.blank?
+        self
+      else
+        spawn.where!(opts, *rest)
+      end
+    end
+
+    def where!(opts, *rest) # :nodoc:
+      references!(PredicateBuilder.references(opts)) if Hash === opts
+
+      self.where_values += build_where(opts, rest)
+      self
+    end
+
+    # Allows you to change a previously set where condition for a given attribute, instead of appending to that condition.
+    #
+    #   Post.where(trashed: true).where(trashed: false)                       # => WHERE `trashed` = 1 AND `trashed` = 0
+    #   Post.where(trashed: true).rewhere(trashed: false)                     # => WHERE `trashed` = 0
+    #   Post.where(active: true).where(trashed: true).rewhere(trashed: false) # => WHERE `active` = 1 AND `trashed` = 0
+    #
+    # This is short-hand for unscope(where: conditions.keys).where(conditions). Note that unlike reorder, we're only unscoping
+    # the named conditions -- not the entire where statement.
+    def rewhere(conditions)
+      unscope(where: conditions.keys).where(conditions)
+    end
+
+    # Allows to specify a HAVING clause. Note that you can't use HAVING
+    # without also specifying a GROUP clause.
+    #
+    #   Order.having('SUM(price) > 30').group('user_id')
+    def having(opts, *rest)
+      opts.blank? ? self : spawn.having!(opts, *rest)
+    end
+
+    def having!(opts, *rest) # :nodoc:
+      references!(PredicateBuilder.references(opts)) if Hash === opts
+
+      self.having_values += build_where(opts, rest)
+      self
+    end
+
+    # Specifies a limit for the number of records to retrieve.
+    #
+    #   User.limit(10) # generated SQL has 'LIMIT 10'
+    #
+    #   User.limit(10).limit(20) # generated SQL has 'LIMIT 20'
+    def limit(value)
+      spawn.limit!(value)
+    end
+
+    def limit!(value) # :nodoc:
+      self.limit_value = value
+      self
+    end
+
+    # Specifies the number of rows to skip before returning rows.
+    #
+    #   User.offset(10) # generated SQL has "OFFSET 10"
+    #
+    # Should be used with order.
+    #
+    #   User.offset(10).order("name ASC")
+    def offset(value)
+      spawn.offset!(value)
+    end
+
+    def offset!(value) # :nodoc:
+      self.offset_value = value
+      self
+    end
+
+    # Specifies locking settings (default to +true+). For more information
+    # on locking, please see +ActiveRecord::Locking+.
+    def lock(locks = true)
+      spawn.lock!(locks)
+    end
+
+    def lock!(locks = true) # :nodoc:
+      case locks
+      when String, TrueClass, NilClass
+        self.lock_value = locks || true
+      else
+        self.lock_value = false
+      end
+
+      self
+    end
+
+    # Returns a chainable relation with zero records.
+    #
+    # The returned relation implements the Null Object pattern. It is an
+    # object with defined null behavior and always returns an empty array of
+    # records without querying the database.
+    #
+    # Any subsequent condition chained to the returned relation will continue
+    # generating an empty relation and will not fire any query to the database.
+    #
+    # Used in cases where a method or scope could return zero records but the
+    # result needs to be chainable.
+    #
+    # For example:
+    #
+    #   @posts = current_user.visible_posts.where(name: params[:name])
+    #   # => the visible_posts method is expected to return a chainable Relation
+    #
+    #   def visible_posts
+    #     case role
+    #     when 'Country Manager'
+    #       Post.where(country: country)
+    #     when 'Reviewer'
+    #       Post.published
+    #     when 'Bad User'
+    #       Post.none # It can't be chained if [] is returned.
+    #     end
+    #   end
+    #
+    def none
+      extending(NullRelation)
+    end
+
+    def none! # :nodoc:
+      extending!(NullRelation)
+    end
+
+    # Sets readonly attributes for the returned relation. If value is
+    # true (default), attempting to update a record will result in an error.
+    #
+    #   users = User.readonly
+    #   users.first.save
+    #   => ActiveRecord::ReadOnlyRecord: ActiveRecord::ReadOnlyRecord
+    def readonly(value = true)
+      spawn.readonly!(value)
+    end
+
+    def readonly!(value = true) # :nodoc:
+      self.readonly_value = value
+      self
+    end
+
+    # Sets attributes to be used when creating new records from a
+    # relation object.
+    #
+    #   users = User.where(name: 'Oscar')
+    #   users.new.name # => 'Oscar'
+    #
+    #   users = users.create_with(name: 'DHH')
+    #   users.new.name # => 'DHH'
+    #
+    # You can pass +nil+ to +create_with+ to reset attributes:
+    #
+    #   users = users.create_with(nil)
+    #   users.new.name # => 'Oscar'
+    def create_with(value)
+      spawn.create_with!(value)
+    end
+
+    def create_with!(value) # :nodoc:
+      self.create_with_value = value ? create_with_value.merge(value) : {}
+      self
+    end
+
+    # Specifies table from which the records will be fetched. For example:
+    #
+    #   Topic.select('title').from('posts')
+    #   # => SELECT title FROM posts
+    #
+    # Can accept other relation objects. For example:
+    #
+    #   Topic.select('title').from(Topic.approved)
+    #   # => SELECT title FROM (SELECT * FROM topics WHERE approved = 't') subquery
+    #
+    #   Topic.select('a.title').from(Topic.approved, :a)
+    #   # => SELECT a.title FROM (SELECT * FROM topics WHERE approved = 't') a
+    #
+    def from(value, subquery_name = nil)
+      spawn.from!(value, subquery_name)
+    end
+
+    def from!(value, subquery_name = nil) # :nodoc:
+      self.from_value = [value, subquery_name]
+      self
+    end
+
+    # Specifies whether the records should be unique or not. For example:
+    #
+    #   User.select(:name)
+    #   # => Might return two records with the same name
+    #
+    #   User.select(:name).distinct
+    #   # => Returns 1 record per distinct name
+    #
+    #   User.select(:name).distinct.distinct(false)
+    #   # => You can also remove the uniqueness
+    def distinct(value = true)
+      spawn.distinct!(value)
+    end
+    alias uniq distinct
+
+    # Like #distinct, but modifies relation in place.
+    def distinct!(value = true) # :nodoc:
+      self.distinct_value = value
+      self
+    end
+    alias uniq! distinct!
+
+    # Used to extend a scope with additional methods, either through
+    # a module or through a block provided.
+    #
+    # The object returned is a relation, which can be further extended.
+    #
+    # === Using a module
+    #
+    #   module Pagination
+    #     def page(number)
+    #       # pagination code goes here
+    #     end
+    #   end
+    #
+    #   scope = Model.all.extending(Pagination)
+    #   scope.page(params[:page])
+    #
+    # You can also pass a list of modules:
+    #
+    #   scope = Model.all.extending(Pagination, SomethingElse)
+    #
+    # === Using a block
+    #
+    #   scope = Model.all.extending do
+    #     def page(number)
+    #       # pagination code goes here
+    #     end
+    #   end
+    #   scope.page(params[:page])
+    #
+    # You can also use a block and a module list:
+    #
+    #   scope = Model.all.extending(Pagination) do
+    #     def per_page(number)
+    #       # pagination code goes here
+    #     end
+    #   end
+    def extending(*modules, &block)
+      if modules.any? || block
+        spawn.extending!(*modules, &block)
+      else
+        self
+      end
+    end
+
+    def extending!(*modules, &block) # :nodoc:
+      modules << Module.new(&block) if block
+      modules.flatten!
+
+      self.extending_values += modules
+      extend(*extending_values) if extending_values.any?
+
+      self
+    end
+
+    # Reverse the existing order clause on the relation.
+    #
+    #   User.order('name ASC').reverse_order # generated SQL has 'ORDER BY name DESC'
+    def reverse_order
+      spawn.reverse_order!
+    end
+
+    def reverse_order! # :nodoc:
+      orders = order_values.uniq
+      orders.reject!(&:blank?)
+      self.order_values = reverse_sql_order(orders)
+      self
+    end
+
+    # Returns the Arel object associated with the relation.
+    def arel # :nodoc:
+      @arel ||= build_arel
+    end
+
+    private
+
+    def build_arel
+      arel = Arel::SelectManager.new(table.engine, table)
+
+      build_joins(arel, joins_values.flatten) unless joins_values.empty?
+
+      collapse_wheres(arel, (where_values - [''])) #TODO: Add uniq with real value comparison / ignore uniqs that have binds
+
+      arel.having(*having_values.uniq.reject(&:blank?)) unless having_values.empty?
+
+      arel.take(connection.sanitize_limit(limit_value)) if limit_value
+      arel.skip(offset_value.to_i) if offset_value
+
+      arel.group(*group_values.uniq.reject(&:blank?)) unless group_values.empty?
+
+      build_order(arel)
+
+      build_select(arel, select_values.uniq)
+
+      arel.distinct(distinct_value)
+      arel.from(build_from) if from_value
+      arel.lock(lock_value) if lock_value
+
+      # Reorder bind indexes if joins produced bind values
+      if arel.bind_values.any?
+        bvs = arel.bind_values + bind_values
+        arel.ast.grep(Arel::Nodes::BindParam).each_with_index do |bp, i|
+          column = bvs[i].first
+          bp.replace connection.substitute_at(column, i)
+        end
+      end
+
+      arel
+    end
+
+    def symbol_unscoping(scope)
+      if !VALID_UNSCOPING_VALUES.include?(scope)
+        raise ArgumentError, "Called unscope() with invalid unscoping argument ':#{scope}'. Valid arguments are :#{VALID_UNSCOPING_VALUES.to_a.join(", :")}."
+      end
+
+      single_val_method = Relation::SINGLE_VALUE_METHODS.include?(scope)
+      unscope_code = "#{scope}_value#{'s' unless single_val_method}="
+
+      case scope
+      when :order
+        result = []
+      when :where
+        self.bind_values = []
+      else
+        result = [] unless single_val_method
+      end
+
+      self.send(unscope_code, result)
+    end
+
+    def where_unscoping(target_value)
+      target_value = target_value.to_s
+
+      where_values.reject! do |rel|
+        case rel
+        when Arel::Nodes::In, Arel::Nodes::NotIn, Arel::Nodes::Equality, Arel::Nodes::NotEqual
+          subrelation = (rel.left.kind_of?(Arel::Attributes::Attribute) ? rel.left : rel.right)
+          subrelation.name == target_value
+        end
+      end
+
+      bind_values.reject! { |col,_| col.name == target_value }
+    end
+
+    def custom_join_ast(table, joins)
+      joins = joins.reject(&:blank?)
+
+      return [] if joins.empty?
+
+      joins.map! do |join|
+        case join
+        when Array
+          join = Arel.sql(join.join(' ')) if array_of_strings?(join)
+        when String
+          join = Arel.sql(join)
+        end
+        table.create_string_join(join)
+      end
+    end
+
+    def collapse_wheres(arel, wheres)
+      predicates = wheres.map do |where|
+        next where if ::Arel::Nodes::Equality === where
+        where = Arel.sql(where) if String === where
+        Arel::Nodes::Grouping.new(where)
+      end
+
+      arel.where(Arel::Nodes::And.new(predicates)) if predicates.present?
+    end
+
+    def build_where(opts, other = [])
+      case opts
+      when String, Array
+        [@klass.send(:sanitize_sql, other.empty? ? opts : ([opts] + other))]
+      when Hash
+        opts = PredicateBuilder.resolve_column_aliases(klass, opts)
+
+        bv_len = bind_values.length
+        tmp_opts, bind_values = create_binds(opts, bv_len)
+        self.bind_values += bind_values
+
+        attributes = @klass.send(:expand_hash_conditions_for_aggregates, tmp_opts)
+        attributes.values.grep(ActiveRecord::Relation) do |rel|
+          self.bind_values += rel.bind_values
+        end
+
+        PredicateBuilder.build_from_hash(klass, attributes, table)
+      else
+        [opts]
+      end
+    end
+
+    def create_binds(opts, idx)
+      bindable, non_binds = opts.partition do |column, value|
+        case value
+        when String, Integer, ActiveRecord::StatementCache::Substitute
+          @klass.columns_hash.include? column.to_s
+        else
+          false
+        end
+      end
+
+      new_opts = {}
+      binds = []
+
+      bindable.each_with_index do |(column,value), index|
+        binds.push [@klass.columns_hash[column.to_s], value]
+        new_opts[column] = connection.substitute_at(column, index + idx)
+      end
+
+      non_binds.each { |column,value| new_opts[column] = value }
+
+      [new_opts, binds]
+    end
+
+    def build_from
+      opts, name = from_value
+      case opts
+      when Relation
+        name ||= 'subquery'
+        self.bind_values = opts.bind_values + self.bind_values
+        opts.arel.as(name.to_s)
+      else
+        opts
+      end
+    end
+
+    def build_joins(manager, joins)
+      buckets = joins.group_by do |join|
+        case join
+        when String
+          :string_join
+        when Hash, Symbol, Array
+          :association_join
+        when ActiveRecord::Associations::JoinDependency
+          :stashed_join
+        when Arel::Nodes::Join
+          :join_node
+        else
+          raise 'unknown class: %s' % join.class.name
+        end
+      end
+
+      association_joins         = buckets[:association_join] || []
+      stashed_association_joins = buckets[:stashed_join] || []
+      join_nodes                = (buckets[:join_node] || []).uniq
+      string_joins              = (buckets[:string_join] || []).map(&:strip).uniq
+
+      join_list = join_nodes + custom_join_ast(manager, string_joins)
+
+      join_dependency = ActiveRecord::Associations::JoinDependency.new(
+        @klass,
+        association_joins,
+        join_list
+      )
+
+      join_infos = join_dependency.join_constraints stashed_association_joins
+
+      join_infos.each do |info|
+        info.joins.each { |join| manager.from(join) }
+        manager.bind_values.concat info.binds
+      end
+
+      manager.join_sources.concat(join_list)
+
+      manager
+    end
+
+    def build_select(arel, selects)
+      if !selects.empty?
+        expanded_select = selects.map do |field|
+          columns_hash.key?(field.to_s) ? arel_table[field] : field
+        end
+        arel.project(*expanded_select)
+      else
+        arel.project(@klass.arel_table[Arel.star])
+      end
+    end
+
+    def reverse_sql_order(order_query)
+      order_query = ["#{quoted_table_name}.#{quoted_primary_key} ASC"] if order_query.empty?
+
+      order_query.flat_map do |o|
+        case o
+        when Arel::Nodes::Ordering
+          o.reverse
+        when String
+          o.to_s.split(',').map! do |s|
+            s.strip!
+            s.gsub!(/\sasc\Z/i, ' DESC') || s.gsub!(/\sdesc\Z/i, ' ASC') || s.concat(' DESC')
+          end
+        else
+          o
+        end
+      end
+    end
+
+    def array_of_strings?(o)
+      o.is_a?(Array) && o.all? { |obj| obj.is_a?(String) }
+    end
+
+    def build_order(arel)
+      orders = order_values.uniq
+      orders.reject!(&:blank?)
+
+      arel.order(*orders) unless orders.empty?
+    end
+
+    VALID_DIRECTIONS = [:asc, :desc, :ASC, :DESC,
+                        'asc', 'desc', 'ASC', 'DESC'] # :nodoc:
+
+    def validate_order_args(args)
+      args.each do |arg|
+        next unless arg.is_a?(Hash)
+        arg.each do |_key, value|
+          raise ArgumentError, "Direction \"#{value}\" is invalid. Valid " \
+                               "directions are: #{VALID_DIRECTIONS.inspect}" unless VALID_DIRECTIONS.include?(value)
+        end
+      end
+    end
+
+    def preprocess_order_args(order_args)
+      order_args.flatten!
+      validate_order_args(order_args)
+
+      references = order_args.grep(String)
+      references.map! { |arg| arg =~ /^([a-zA-Z]\w*)\.(\w+)/ && $1 }.compact!
+      references!(references) if references.any?
+
+      # if a symbol is given we prepend the quoted table name
+      order_args.map! do |arg|
+        case arg
+        when Symbol
+          arg = klass.attribute_alias(arg) if klass.attribute_alias?(arg)
+          table[arg].asc
+        when Hash
+          arg.map { |field, dir|
+            field = klass.attribute_alias(field) if klass.attribute_alias?(field)
+            table[field].send(dir.downcase)
+          }
+        else
+          arg
+        end
+      end.flatten!
+    end
+
+    # Checks to make sure that the arguments are not blank. Note that if some
+    # blank-like object were initially passed into the query method, then this
+    # method will not raise an error.
+    #
+    # Example:
+    #
+    #    Post.references()   # => raises an error
+    #    Post.references([]) # => does not raise an error
+    #
+    # This particular method should be called with a method_name and the args
+    # passed into that method as an input. For example:
+    #
+    # def references(*args)
+    #   check_if_method_has_arguments!("references", args)
+    #   ...
+    # end
+    def check_if_method_has_arguments!(method_name, args)
+      if args.blank?
+        raise ArgumentError, "The method .#{method_name}() must contain arguments."
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/relation/spawn_methods.rb b/activerecord/lib/active_record/relation/spawn_methods.rb
new file mode 100644
index 0000000000..57d66bce4b
--- /dev/null
+++ b/activerecord/lib/active_record/relation/spawn_methods.rb
@@ -0,0 +1,75 @@
+require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/hash/slice'
+require 'active_record/relation/merger'
+
+module ActiveRecord
+  module SpawnMethods
+
+    # This is overridden by Associations::CollectionProxy
+    def spawn #:nodoc:
+      clone
+    end
+
+    # Merges in the conditions from <tt>other</tt>, if <tt>other</tt> is an <tt>ActiveRecord::Relation</tt>.
+    # Returns an array representing the intersection of the resulting records with <tt>other</tt>, if <tt>other</tt> is an array.
+    #   Post.where(published: true).joins(:comments).merge( Comment.where(spam: false) )
+    #   # Performs a single join query with both where conditions.
+    #
+    #   recent_posts = Post.order('created_at DESC').first(5)
+    #   Post.where(published: true).merge(recent_posts)
+    #   # Returns the intersection of all published posts with the 5 most recently created posts.
+    #   # (This is just an example. You'd probably want to do this with a single query!)
+    #
+    # Procs will be evaluated by merge:
+    #
+    #   Post.where(published: true).merge(-> { joins(:comments) })
+    #   # => Post.where(published: true).joins(:comments)
+    #
+    # This is mainly intended for sharing common conditions between multiple associations.
+    def merge(other)
+      if other.is_a?(Array)
+        to_a & other
+      elsif other
+        spawn.merge!(other)
+      else
+        self
+      end
+    end
+
+    def merge!(other) # :nodoc:
+      if !other.is_a?(Relation) && other.respond_to?(:to_proc)
+        instance_exec(&other)
+      else
+        klass = other.is_a?(Hash) ? Relation::HashMerger : Relation::Merger
+        klass.new(self, other).merge
+      end
+    end
+
+    # Removes from the query the condition(s) specified in +skips+.
+    #
+    #   Post.order('id asc').except(:order)                  # discards the order condition
+    #   Post.where('id > 10').order('id asc').except(:where) # discards the where condition but keeps the order
+    def except(*skips)
+      relation_with values.except(*skips)
+    end
+
+    # Removes any condition from the query other than the one(s) specified in +onlies+.
+    #
+    #   Post.order('id asc').only(:where)         # discards the order condition
+    #   Post.order('id asc').only(:where, :order) # uses the specified order
+    def only(*onlies)
+      if onlies.any? { |o| o == :where }
+        onlies << :bind
+      end
+      relation_with values.slice(*onlies)
+    end
+
+    private
+
+      def relation_with(values) # :nodoc:
+        result = Relation.create(klass, table, values)
+        result.extend(*extending_values) if extending_values.any?
+        result
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/result.rb b/activerecord/lib/active_record/result.rb
new file mode 100644
index 0000000000..8405fdaeb9
--- /dev/null
+++ b/activerecord/lib/active_record/result.rb
@@ -0,0 +1,127 @@
+module ActiveRecord
+  ###
+  # This class encapsulates a Result returned from calling +exec_query+ on any
+  # database connection adapter. For example:
+  #
+  #   result = ActiveRecord::Base.connection.exec_query('SELECT id, title, body FROM posts')
+  #   result # => #<ActiveRecord::Result:0xdeadbeef>
+  #
+  #   # Get the column names of the result:
+  #   result.columns
+  #   # => ["id", "title", "body"]
+  #
+  #   # Get the record values of the result:
+  #   result.rows
+  #   # => [[1, "title_1", "body_1"],
+  #         [2, "title_2", "body_2"],
+  #         ...
+  #        ]
+  #
+  #   # Get an array of hashes representing the result (column => value):
+  #   result.to_hash
+  #   # => [{"id" => 1, "title" => "title_1", "body" => "body_1"},
+  #         {"id" => 2, "title" => "title_2", "body" => "body_2"},
+  #         ...
+  #        ]
+  #
+  #   # ActiveRecord::Result also includes Enumerable.
+  #   result.each do |row|
+  #     puts row['title'] + " " + row['body']
+  #   end
+  class Result
+    include Enumerable
+
+    IDENTITY_TYPE = Type::Value.new # :nodoc:
+
+    attr_reader :columns, :rows, :column_types
+
+    def initialize(columns, rows, column_types = {})
+      @columns      = columns
+      @rows         = rows
+      @hash_rows    = nil
+      @column_types = column_types
+    end
+
+    def each
+      if block_given?
+        hash_rows.each { |row| yield row }
+      else
+        hash_rows.to_enum { @rows.size }
+      end
+    end
+
+    def to_hash
+      hash_rows
+    end
+
+    alias :map! :map
+    alias :collect! :map
+
+    # Returns true if there are no records.
+    def empty?
+      rows.empty?
+    end
+
+    def to_ary
+      hash_rows
+    end
+
+    def [](idx)
+      hash_rows[idx]
+    end
+
+    def last
+      hash_rows.last
+    end
+
+    def cast_values(type_overrides = {}) # :nodoc:
+      types = columns.map { |name| column_type(name, type_overrides) }
+      result = rows.map do |values|
+        types.zip(values).map { |type, value| type.type_cast_from_database(value) }
+      end
+
+      columns.one? ? result.map!(&:first) : result
+    end
+
+    def initialize_copy(other)
+      @columns      = columns.dup
+      @rows         = rows.dup
+      @column_types = column_types.dup
+      @hash_rows    = nil
+    end
+
+    private
+
+    def column_type(name, type_overrides = {})
+      type_overrides.fetch(name) do
+        column_types.fetch(name, IDENTITY_TYPE)
+      end
+    end
+
+    def hash_rows
+      @hash_rows ||=
+        begin
+          # We freeze the strings to prevent them getting duped when
+          # used as keys in ActiveRecord::Base's @attributes hash
+          columns = @columns.map { |c| c.dup.freeze }
+          @rows.map { |row|
+            # In the past we used Hash[columns.zip(row)]
+            #  though elegant, the verbose way is much more efficient
+            #  both time and memory wise cause it avoids a big array allocation
+            #  this method is called a lot and needs to be micro optimised
+            hash = {}
+
+            index = 0
+            length = columns.length
+
+            while index < length
+              hash[columns[index]] = row[index]
+              index += 1
+            end
+
+            hash
+          }
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/runtime_registry.rb b/activerecord/lib/active_record/runtime_registry.rb
new file mode 100644
index 0000000000..9d605b826a
--- /dev/null
+++ b/activerecord/lib/active_record/runtime_registry.rb
@@ -0,0 +1,22 @@
+require 'active_support/per_thread_registry'
+
+module ActiveRecord
+  # This is a thread locals registry for Active Record. For example:
+  #
+  #   ActiveRecord::RuntimeRegistry.connection_handler
+  #
+  # returns the connection handler local to the current thread.
+  #
+  # See the documentation of <tt>ActiveSupport::PerThreadRegistry</tt>
+  # for further details.
+  class RuntimeRegistry # :nodoc:
+    extend ActiveSupport::PerThreadRegistry
+
+    attr_accessor :connection_handler, :sql_runtime, :connection_id
+
+    [:connection_handler, :sql_runtime, :connection_id].each do |val|
+      class_eval %{ def self.#{val}; instance.#{val}; end }, __FILE__, __LINE__
+      class_eval %{ def self.#{val}=(x); instance.#{val}=x; end }, __FILE__, __LINE__
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/sanitization.rb b/activerecord/lib/active_record/sanitization.rb
new file mode 100644
index 0000000000..ff70cbed0f
--- /dev/null
+++ b/activerecord/lib/active_record/sanitization.rb
@@ -0,0 +1,188 @@
+module ActiveRecord
+  module Sanitization
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def quote_value(value, column) #:nodoc:
+        connection.quote(value, column)
+      end
+
+      # Used to sanitize objects before they're used in an SQL SELECT statement. Delegates to <tt>connection.quote</tt>.
+      def sanitize(object) #:nodoc:
+        connection.quote(object)
+      end
+
+      protected
+
+      # Accepts an array, hash, or string of SQL conditions and sanitizes
+      # them into a valid SQL fragment for a WHERE clause.
+      #   ["name='%s' and group_id='%s'", "foo'bar", 4]  returns  "name='foo''bar' and group_id='4'"
+      #   { name: "foo'bar", group_id: 4 }  returns "name='foo''bar' and group_id='4'"
+      #   "name='foo''bar' and group_id='4'" returns "name='foo''bar' and group_id='4'"
+      def sanitize_sql_for_conditions(condition, table_name = self.table_name)
+        return nil if condition.blank?
+
+        case condition
+        when Array; sanitize_sql_array(condition)
+        when Hash;  sanitize_sql_hash_for_conditions(condition, table_name)
+        else        condition
+        end
+      end
+      alias_method :sanitize_sql, :sanitize_sql_for_conditions
+      alias_method :sanitize_conditions, :sanitize_sql
+
+      # Accepts an array, hash, or string of SQL conditions and sanitizes
+      # them into a valid SQL fragment for a SET clause.
+      #   { name: nil, group_id: 4 }  returns "name = NULL , group_id='4'"
+      def sanitize_sql_for_assignment(assignments, default_table_name = self.table_name)
+        case assignments
+        when Array; sanitize_sql_array(assignments)
+        when Hash;  sanitize_sql_hash_for_assignment(assignments, default_table_name)
+        else        assignments
+        end
+      end
+
+      # Accepts a hash of SQL conditions and replaces those attributes
+      # that correspond to a +composed_of+ relationship with their expanded
+      # aggregate attribute values.
+      # Given:
+      #     class Person < ActiveRecord::Base
+      #       composed_of :address, class_name: "Address",
+      #         mapping: [%w(address_street street), %w(address_city city)]
+      #     end
+      # Then:
+      #     { address: Address.new("813 abc st.", "chicago") }
+      #       # => { address_street: "813 abc st.", address_city: "chicago" }
+      def expand_hash_conditions_for_aggregates(attrs)
+        expanded_attrs = {}
+        attrs.each do |attr, value|
+          if aggregation = reflect_on_aggregation(attr.to_sym)
+            mapping = aggregation.mapping
+            mapping.each do |field_attr, aggregate_attr|
+              if mapping.size == 1 && !value.respond_to?(aggregate_attr)
+                expanded_attrs[field_attr] = value
+              else
+                expanded_attrs[field_attr] = value.send(aggregate_attr)
+              end
+            end
+          else
+            expanded_attrs[attr] = value
+          end
+        end
+        expanded_attrs
+      end
+
+      # Sanitizes a hash of attribute/value pairs into SQL conditions for a WHERE clause.
+      #   { name: "foo'bar", group_id: 4 }
+      #     # => "name='foo''bar' and group_id= 4"
+      #   { status: nil, group_id: [1,2,3] }
+      #     # => "status IS NULL and group_id IN (1,2,3)"
+      #   { age: 13..18 }
+      #     # => "age BETWEEN 13 AND 18"
+      #   { 'other_records.id' => 7 }
+      #     # => "`other_records`.`id` = 7"
+      #   { other_records: { id: 7 } }
+      #     # => "`other_records`.`id` = 7"
+      # And for value objects on a composed_of relationship:
+      #   { address: Address.new("123 abc st.", "chicago") }
+      #     # => "address_street='123 abc st.' and address_city='chicago'"
+      def sanitize_sql_hash_for_conditions(attrs, default_table_name = self.table_name)
+        attrs = PredicateBuilder.resolve_column_aliases self, attrs
+        attrs = expand_hash_conditions_for_aggregates(attrs)
+
+        table = Arel::Table.new(table_name, arel_engine).alias(default_table_name)
+        PredicateBuilder.build_from_hash(self, attrs, table).map { |b|
+          connection.visitor.compile b
+        }.join(' AND ')
+      end
+      alias_method :sanitize_sql_hash, :sanitize_sql_hash_for_conditions
+
+      # Sanitizes a hash of attribute/value pairs into SQL conditions for a SET clause.
+      #   { status: nil, group_id: 1 }
+      #     # => "status = NULL , group_id = 1"
+      def sanitize_sql_hash_for_assignment(attrs, table)
+        c = connection
+        attrs.map do |attr, value|
+          "#{c.quote_table_name_for_assignment(table, attr)} = #{quote_bound_value(value, c, columns_hash[attr.to_s])}"
+        end.join(', ')
+      end
+
+      # Sanitizes a +string+ so that it is safe to use within an SQL
+      # LIKE statement. This method uses +escape_character+ to escape all occurrences of "\", "_" and "%"
+      def sanitize_sql_like(string, escape_character = "\\")
+        pattern = Regexp.union(escape_character, "%", "_")
+        string.gsub(pattern) { |x| [escape_character, x].join }
+      end
+
+      # Accepts an array of conditions. The array has each value
+      # sanitized and interpolated into the SQL statement.
+      #   ["name='%s' and group_id='%s'", "foo'bar", 4]  returns  "name='foo''bar' and group_id='4'"
+      def sanitize_sql_array(ary)
+        statement, *values = ary
+        if values.first.is_a?(Hash) && statement =~ /:\w+/
+          replace_named_bind_variables(statement, values.first)
+        elsif statement.include?('?')
+          replace_bind_variables(statement, values)
+        elsif statement.blank?
+          statement
+        else
+          statement % values.collect { |value| connection.quote_string(value.to_s) }
+        end
+      end
+
+      def replace_bind_variables(statement, values) #:nodoc:
+        raise_if_bind_arity_mismatch(statement, statement.count('?'), values.size)
+        bound = values.dup
+        c = connection
+        statement.gsub('?') do
+          replace_bind_variable(bound.shift, c)
+        end
+      end
+
+      def replace_bind_variable(value, c = connection) #:nodoc:
+        if ActiveRecord::Relation === value
+          value.to_sql
+        else
+          quote_bound_value(value, c)
+        end
+      end
+
+      def replace_named_bind_variables(statement, bind_vars) #:nodoc:
+        statement.gsub(/(:?):([a-zA-Z]\w*)/) do
+          if $1 == ':' # skip postgresql casts
+            $& # return the whole match
+          elsif bind_vars.include?(match = $2.to_sym)
+            replace_bind_variable(bind_vars[match])
+          else
+            raise PreparedStatementInvalid, "missing value for :#{match} in #{statement}"
+          end
+        end
+      end
+
+      def quote_bound_value(value, c = connection, column = nil) #:nodoc:
+        if column
+          c.quote(value, column)
+        elsif value.respond_to?(:map) && !value.acts_like?(:string)
+          if value.respond_to?(:empty?) && value.empty?
+            c.quote(nil)
+          else
+            value.map { |v| c.quote(v) }.join(',')
+          end
+        else
+          c.quote(value)
+        end
+      end
+
+      def raise_if_bind_arity_mismatch(statement, expected, provided) #:nodoc:
+        unless expected == provided
+          raise PreparedStatementInvalid, "wrong number of bind variables (#{provided} for #{expected}) in: #{statement}"
+        end
+      end
+    end
+
+    # TODO: Deprecate this
+    def quoted_id
+      self.class.quote_value(id, column_for_attribute(self.class.primary_key))
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/schema.rb b/activerecord/lib/active_record/schema.rb
new file mode 100644
index 0000000000..0a5546a760
--- /dev/null
+++ b/activerecord/lib/active_record/schema.rb
@@ -0,0 +1,64 @@
+module ActiveRecord
+  # = Active Record Schema
+  #
+  # Allows programmers to programmatically define a schema in a portable
+  # DSL. This means you can define tables, indexes, etc. without using SQL
+  # directly, so your applications can more easily support multiple
+  # databases.
+  #
+  # Usage:
+  #
+  #   ActiveRecord::Schema.define do
+  #     create_table :authors do |t|
+  #       t.string :name, null: false
+  #     end
+  #
+  #     add_index :authors, :name, :unique
+  #
+  #     create_table :posts do |t|
+  #       t.integer :author_id, null: false
+  #       t.string :subject
+  #       t.text :body
+  #       t.boolean :private, default: false
+  #     end
+  #
+  #     add_index :posts, :author_id
+  #   end
+  #
+  # ActiveRecord::Schema is only supported by database adapters that also
+  # support migrations, the two features being very similar.
+  class Schema < Migration
+
+    # Returns the migrations paths.
+    #
+    #   ActiveRecord::Schema.new.migrations_paths
+    #   # => ["db/migrate"] # Rails migration path by default.
+    def migrations_paths
+      ActiveRecord::Migrator.migrations_paths
+    end
+
+    def define(info, &block) # :nodoc:
+      instance_eval(&block)
+
+      unless info[:version].blank?
+        initialize_schema_migrations_table
+        connection.assume_migrated_upto_version(info[:version], migrations_paths)
+      end
+    end
+
+    # Eval the given block. All methods available to the current connection
+    # adapter are available within the block, so you can easily use the
+    # database definition DSL to build up your schema (+create_table+,
+    # +add_index+, etc.).
+    #
+    # The +info+ hash is optional, and if given is used to define metadata
+    # about the current schema (currently, only the schema's version):
+    #
+    #   ActiveRecord::Schema.define(version: 20380119000001) do
+    #     ...
+    #   end
+    def self.define(info={}, &block)
+      new.define(info, &block)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
new file mode 100644
index 0000000000..fae6427ea1
--- /dev/null
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -0,0 +1,262 @@
+require 'stringio'
+require 'active_support/core_ext/big_decimal'
+
+module ActiveRecord
+  # = Active Record Schema Dumper
+  #
+  # This class is used to dump the database schema for some connection to some
+  # output format (i.e., ActiveRecord::Schema).
+  class SchemaDumper #:nodoc:
+    private_class_method :new
+
+    ##
+    # :singleton-method:
+    # A list of tables which should not be dumped to the schema.
+    # Acceptable values are strings as well as regexp.
+    # This setting is only used if ActiveRecord::Base.schema_format == :ruby
+    cattr_accessor :ignore_tables
+    @@ignore_tables = []
+
+    class << self
+      def dump(connection=ActiveRecord::Base.connection, stream=STDOUT, config = ActiveRecord::Base)
+        new(connection, generate_options(config)).dump(stream)
+        stream
+      end
+
+      private
+        def generate_options(config)
+          {
+            table_name_prefix: config.table_name_prefix,
+            table_name_suffix: config.table_name_suffix
+          }
+        end
+    end
+
+    def dump(stream)
+      header(stream)
+      extensions(stream)
+      tables(stream)
+      trailer(stream)
+      stream
+    end
+
+    private
+
+      def initialize(connection, options = {})
+        @connection = connection
+        @types = @connection.native_database_types
+        @version = Migrator::current_version rescue nil
+        @options = options
+      end
+
+      def header(stream)
+        define_params = @version ? "version: #{@version}" : ""
+
+        if stream.respond_to?(:external_encoding) && stream.external_encoding
+          stream.puts "# encoding: #{stream.external_encoding.name}"
+        end
+
+        stream.puts <<HEADER
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# Note that this schema.rb definition is the authoritative source for your
+# database schema. If you need to create the application database on another
+# system, you should be using db:schema:load, not running all the migrations
+# from scratch. The latter is a flawed and unsustainable approach (the more migrations
+# you'll amass, the slower it'll run and the greater likelihood for issues).
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema.define(#{define_params}) do
+
+HEADER
+      end
+
+      def trailer(stream)
+        stream.puts "end"
+      end
+
+      def extensions(stream)
+        return unless @connection.supports_extensions?
+        extensions = @connection.extensions
+        if extensions.any?
+          stream.puts "  # These are extensions that must be enabled in order to support this database"
+          extensions.each do |extension|
+            stream.puts "  enable_extension #{extension.inspect}"
+          end
+          stream.puts
+        end
+      end
+
+      def tables(stream)
+        sorted_tables = @connection.tables.sort
+
+        sorted_tables.each do |table_name|
+          table(table_name, stream) unless ignored?(table_name)
+        end
+
+        # dump foreign keys at the end to make sure all dependent tables exist.
+        if @connection.supports_foreign_keys?
+          sorted_tables.each do |tbl|
+            foreign_keys(tbl, stream)
+          end
+        end
+      end
+
+      def table(table, stream)
+        columns = @connection.columns(table)
+        begin
+          tbl = StringIO.new
+
+          # first dump primary key column
+          if @connection.respond_to?(:pk_and_sequence_for)
+            pk, _ = @connection.pk_and_sequence_for(table)
+          end
+          if !pk && @connection.respond_to?(:primary_key)
+            pk = @connection.primary_key(table)
+          end
+
+          tbl.print "  create_table #{remove_prefix_and_suffix(table).inspect}"
+          pkcol = columns.detect { |c| c.name == pk }
+          if pkcol
+            if pk != 'id'
+              tbl.print %Q(, primary_key: "#{pk}")
+            elsif pkcol.sql_type == 'uuid'
+              tbl.print ", id: :uuid"
+              tbl.print %Q(, default: "#{pkcol.default_function}") if pkcol.default_function
+            end
+          else
+            tbl.print ", id: false"
+          end
+          tbl.print ", force: true"
+          tbl.puts " do |t|"
+
+          # then dump all non-primary key columns
+          column_specs = columns.map do |column|
+            raise StandardError, "Unknown type '#{column.sql_type}' for column '#{column.name}'" unless @connection.valid_type?(column.type)
+            next if column.name == pk
+            @connection.column_spec(column, @types)
+          end.compact
+
+          # find all migration keys used in this table
+          keys = @connection.migration_keys
+
+          # figure out the lengths for each column based on above keys
+          lengths = keys.map { |key|
+            column_specs.map { |spec|
+              spec[key] ? spec[key].length + 2 : 0
+            }.max
+          }
+
+          # the string we're going to sprintf our values against, with standardized column widths
+          format_string = lengths.map{ |len| "%-#{len}s" }
+
+          # find the max length for the 'type' column, which is special
+          type_length = column_specs.map{ |column| column[:type].length }.max
+
+          # add column type definition to our format string
+          format_string.unshift "    t.%-#{type_length}s "
+
+          format_string *= ''
+
+          column_specs.each do |colspec|
+            values = keys.zip(lengths).map{ |key, len| colspec.key?(key) ? colspec[key] + ", " : " " * len }
+            values.unshift colspec[:type]
+            tbl.print((format_string % values).gsub(/,\s*$/, ''))
+            tbl.puts
+          end
+
+          tbl.puts "  end"
+          tbl.puts
+
+          indexes(table, tbl)
+
+          tbl.rewind
+          stream.print tbl.read
+        rescue => e
+          stream.puts "# Could not dump table #{table.inspect} because of following #{e.class}"
+          stream.puts "#   #{e.message}"
+          stream.puts
+        end
+
+        stream
+      end
+
+      def indexes(table, stream)
+        if (indexes = @connection.indexes(table)).any?
+          add_index_statements = indexes.map do |index|
+            statement_parts = [
+              ('add_index ' + remove_prefix_and_suffix(index.table).inspect),
+              index.columns.inspect,
+              ('name: ' + index.name.inspect),
+            ]
+            statement_parts << 'unique: true' if index.unique
+
+            index_lengths = (index.lengths || []).compact
+            statement_parts << ('length: ' + Hash[index.columns.zip(index.lengths)].inspect) unless index_lengths.empty?
+
+            index_orders = (index.orders || {})
+            statement_parts << ('order: ' + index.orders.inspect) unless index_orders.empty?
+
+            statement_parts << ('where: ' + index.where.inspect) if index.where
+
+            statement_parts << ('using: ' + index.using.inspect) if index.using
+
+            statement_parts << ('type: ' + index.type.inspect) if index.type
+
+            '  ' + statement_parts.join(', ')
+          end
+
+          stream.puts add_index_statements.sort.join("\n")
+          stream.puts
+        end
+      end
+
+      def foreign_keys(table, stream)
+        if (foreign_keys = @connection.foreign_keys(table)).any?
+          add_foreign_key_statements = foreign_keys.map do |foreign_key|
+            parts = [
+                     'add_foreign_key ' + remove_prefix_and_suffix(foreign_key.from_table).inspect,
+                     remove_prefix_and_suffix(foreign_key.to_table).inspect,
+                    ]
+
+            if foreign_key.column != @connection.foreign_key_column_for(foreign_key.to_table)
+              parts << ('column: ' + foreign_key.column.inspect)
+            end
+
+            if foreign_key.custom_primary_key?
+              parts << ('primary_key: ' + foreign_key.primary_key.inspect)
+            end
+
+            if foreign_key.name !~ /^fk_rails_[0-9a-f]{10}$/
+              parts << ('name: ' + foreign_key.name.inspect)
+            end
+
+            parts << ('on_update: ' + foreign_key.on_update.inspect) if foreign_key.on_update
+            parts << ('on_delete: ' + foreign_key.on_delete.inspect) if foreign_key.on_delete
+
+            '  ' + parts.join(', ')
+          end
+
+          stream.puts add_foreign_key_statements.sort.join("\n")
+        end
+      end
+
+      def remove_prefix_and_suffix(table)
+        table.gsub(/^(#{@options[:table_name_prefix]})(.+)(#{@options[:table_name_suffix]})$/,  "\\2")
+      end
+
+      def ignored?(table_name)
+        ['schema_migrations', ignore_tables].flatten.any? do |ignored|
+          case ignored
+          when String; remove_prefix_and_suffix(table_name) == ignored
+          when Regexp; remove_prefix_and_suffix(table_name) =~ ignored
+          else
+            raise StandardError, 'ActiveRecord::SchemaDumper.ignore_tables accepts an array of String and / or Regexp values.'
+          end
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/schema_migration.rb b/activerecord/lib/active_record/schema_migration.rb
new file mode 100644
index 0000000000..b5038104ac
--- /dev/null
+++ b/activerecord/lib/active_record/schema_migration.rb
@@ -0,0 +1,56 @@
+require 'active_record/scoping/default'
+require 'active_record/scoping/named'
+require 'active_record/base'
+
+module ActiveRecord
+  class SchemaMigration < ActiveRecord::Base
+    class << self
+      def primary_key
+        nil
+      end
+
+      def table_name
+        "#{table_name_prefix}#{ActiveRecord::Base.schema_migrations_table_name}#{table_name_suffix}"
+      end
+
+      def index_name
+        "#{table_name_prefix}unique_#{ActiveRecord::Base.schema_migrations_table_name}#{table_name_suffix}"
+      end
+
+      def table_exists?
+        connection.table_exists?(table_name)
+      end
+
+      def create_table(limit=nil)
+        unless table_exists?
+          version_options = {null: false}
+          version_options[:limit] = limit if limit
+
+          connection.create_table(table_name, id: false) do |t|
+            t.column :version, :string, version_options
+          end
+          connection.add_index table_name, :version, unique: true, name: index_name
+        end
+      end
+
+      def drop_table
+        if table_exists?
+          connection.remove_index table_name, name: index_name
+          connection.drop_table(table_name)
+        end
+      end
+
+      def normalize_migration_number(number)
+        "%.3d" % number.to_i
+      end
+
+      def normalized_versions
+        pluck(:version).map { |v| normalize_migration_number v }
+      end
+    end
+
+    def version
+      super.to_i
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/scoping.rb b/activerecord/lib/active_record/scoping.rb
new file mode 100644
index 0000000000..3e43591672
--- /dev/null
+++ b/activerecord/lib/active_record/scoping.rb
@@ -0,0 +1,87 @@
+require 'active_support/per_thread_registry'
+
+module ActiveRecord
+  module Scoping
+    extend ActiveSupport::Concern
+
+    included do
+      include Default
+      include Named
+    end
+
+    module ClassMethods
+      def current_scope #:nodoc:
+        ScopeRegistry.value_for(:current_scope, base_class.to_s)
+      end
+
+      def current_scope=(scope) #:nodoc:
+        ScopeRegistry.set_value_for(:current_scope, base_class.to_s, scope)
+      end
+    end
+
+    def populate_with_current_scope_attributes
+      return unless self.class.scope_attributes?
+
+      self.class.scope_attributes.each do |att,value|
+        send("#{att}=", value) if respond_to?("#{att}=")
+      end
+    end
+
+    def initialize_internals_callback
+      super
+      populate_with_current_scope_attributes
+    end
+
+    # This class stores the +:current_scope+ and +:ignore_default_scope+ values
+    # for different classes. The registry is stored as a thread local, which is
+    # accessed through +ScopeRegistry.current+.
+    #
+    # This class allows you to store and get the scope values on different
+    # classes and different types of scopes. For example, if you are attempting
+    # to get the current_scope for the +Board+ model, then you would use the
+    # following code:
+    #
+    #   registry = ActiveRecord::Scoping::ScopeRegistry
+    #   registry.set_value_for(:current_scope, "Board", some_new_scope)
+    #
+    # Now when you run:
+    #
+    #   registry.value_for(:current_scope, "Board")
+    #
+    # You will obtain whatever was defined in +some_new_scope+. The +value_for+
+    # and +set_value_for+ methods are delegated to the current +ScopeRegistry+
+    # object, so the above example code can also be called as:
+    #
+    #   ActiveRecord::Scoping::ScopeRegistry.set_value_for(:current_scope,
+    #       "Board", some_new_scope)
+    class ScopeRegistry # :nodoc:
+      extend ActiveSupport::PerThreadRegistry
+
+      VALID_SCOPE_TYPES = [:current_scope, :ignore_default_scope]
+
+      def initialize
+        @registry = Hash.new { |hash, key| hash[key] = {} }
+      end
+
+      # Obtains the value for a given +scope_name+ and +variable_name+.
+      def value_for(scope_type, variable_name)
+        raise_invalid_scope_type!(scope_type)
+        @registry[scope_type][variable_name]
+      end
+
+      # Sets the +value+ for a given +scope_type+ and +variable_name+.
+      def set_value_for(scope_type, variable_name, value)
+        raise_invalid_scope_type!(scope_type)
+        @registry[scope_type][variable_name] = value
+      end
+
+      private
+
+      def raise_invalid_scope_type!(scope_type)
+        if !VALID_SCOPE_TYPES.include?(scope_type)
+          raise ArgumentError, "Invalid scope type '#{scope_type}' sent to the registry. Scope types must be included in VALID_SCOPE_TYPES"
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
new file mode 100644
index 0000000000..18190cb535
--- /dev/null
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -0,0 +1,134 @@
+module ActiveRecord
+  module Scoping
+    module Default
+      extend ActiveSupport::Concern
+
+      included do
+        # Stores the default scope for the class.
+        class_attribute :default_scopes, instance_writer: false, instance_predicate: false
+
+        self.default_scopes = []
+      end
+
+      module ClassMethods
+        # Returns a scope for the model without the previously set scopes.
+        #
+        #   class Post < ActiveRecord::Base
+        #     def self.default_scope
+        #       where published: true
+        #     end
+        #   end
+        #
+        #   Post.all                                  # Fires "SELECT * FROM posts WHERE published = true"
+        #   Post.unscoped.all                         # Fires "SELECT * FROM posts"
+        #   Post.where(published: false).unscoped.all # Fires "SELECT * FROM posts"
+        #
+        # This method also accepts a block. All queries inside the block will
+        # not use the previously set scopes.
+        #
+        #   Post.unscoped {
+        #     Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10"
+        #   }
+        def unscoped
+          block_given? ? relation.scoping { yield } : relation
+        end
+
+        def before_remove_const #:nodoc:
+          self.current_scope = nil
+        end
+
+        protected
+
+        # Use this macro in your model to set a default scope for all operations on
+        # the model.
+        #
+        #   class Article < ActiveRecord::Base
+        #     default_scope { where(published: true) }
+        #   end
+        #
+        #   Article.all # => SELECT * FROM articles WHERE published = true
+        #
+        # The +default_scope+ is also applied while creating/building a record.
+        # It is not applied while updating a record.
+        #
+        #   Article.new.published    # => true
+        #   Article.create.published # => true
+        #
+        # (You can also pass any object which responds to +call+ to the
+        # +default_scope+ macro, and it will be called when building the
+        # default scope.)
+        #
+        # If you use multiple +default_scope+ declarations in your model then
+        # they will be merged together:
+        #
+        #   class Article < ActiveRecord::Base
+        #     default_scope { where(published: true) }
+        #     default_scope { where(rating: 'G') }
+        #   end
+        #
+        #   Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'
+        #
+        # This is also the case with inheritance and module includes where the
+        # parent or module defines a +default_scope+ and the child or including
+        # class defines a second one.
+        #
+        # If you need to do more complex things with a default scope, you can
+        # alternatively define it as a class method:
+        #
+        #   class Article < ActiveRecord::Base
+        #     def self.default_scope
+        #       # Should return a scope, you can call 'super' here etc.
+        #     end
+        #   end
+        def default_scope(scope = nil)
+          scope = Proc.new if block_given?
+
+          if scope.is_a?(Relation) || !scope.respond_to?(:call)
+            raise ArgumentError,
+              "Support for calling #default_scope without a block is removed. For example instead " \
+              "of `default_scope where(color: 'red')`, please use " \
+              "`default_scope { where(color: 'red') }`. (Alternatively you can just redefine " \
+              "self.default_scope.)"
+          end
+
+          self.default_scopes += [scope]
+        end
+
+        def build_default_scope(base_rel = relation) # :nodoc:
+          if !Base.is_a?(method(:default_scope).owner)
+            # The user has defined their own default scope method, so call that
+            evaluate_default_scope { default_scope }
+          elsif default_scopes.any?
+            evaluate_default_scope do
+              default_scopes.inject(base_rel) do |default_scope, scope|
+                default_scope.merge(base_rel.scoping { scope.call })
+              end
+            end
+          end
+        end
+
+        def ignore_default_scope? # :nodoc:
+          ScopeRegistry.value_for(:ignore_default_scope, self)
+        end
+
+        def ignore_default_scope=(ignore) # :nodoc:
+          ScopeRegistry.set_value_for(:ignore_default_scope, self, ignore)
+        end
+
+        # The ignore_default_scope flag is used to prevent an infinite recursion
+        # situation where a default scope references a scope which has a default
+        # scope which references a scope...
+        def evaluate_default_scope # :nodoc:
+          return if ignore_default_scope?
+
+          begin
+            self.ignore_default_scope = true
+            yield
+          ensure
+            self.ignore_default_scope = false
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/scoping/named.rb b/activerecord/lib/active_record/scoping/named.rb
new file mode 100644
index 0000000000..49cadb66d0
--- /dev/null
+++ b/activerecord/lib/active_record/scoping/named.rb
@@ -0,0 +1,160 @@
+require 'active_support/core_ext/array'
+require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/kernel/singleton_class'
+
+module ActiveRecord
+  # = Active Record \Named \Scopes
+  module Scoping
+    module Named
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        # Returns an <tt>ActiveRecord::Relation</tt> scope object.
+        #
+        #   posts = Post.all
+        #   posts.size # Fires "select count(*) from  posts" and returns the count
+        #   posts.each {|p| puts p.name } # Fires "select * from posts" and loads post objects
+        #
+        #   fruits = Fruit.all
+        #   fruits = fruits.where(color: 'red') if options[:red_only]
+        #   fruits = fruits.limit(10) if limited?
+        #
+        # You can define a scope that applies to all finders using
+        # <tt>ActiveRecord::Base.default_scope</tt>.
+        def all
+          if current_scope
+            current_scope.clone
+          else
+            default_scoped
+          end
+        end
+
+        def default_scoped # :nodoc:
+          relation.merge(build_default_scope)
+        end
+
+        # Collects attributes from scopes that should be applied when creating
+        # an AR instance for the particular class this is called on.
+        def scope_attributes # :nodoc:
+          all.scope_for_create
+        end
+
+        # Are there default attributes associated with this scope?
+        def scope_attributes? # :nodoc:
+          current_scope || default_scopes.any?
+        end
+
+        # Adds a class method for retrieving and querying objects. A \scope
+        # represents a narrowing of a database query, such as
+        # <tt>where(color: :red).select('shirts.*').includes(:washing_instructions)</tt>.
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     scope :red, -> { where(color: 'red') }
+        #     scope :dry_clean_only, -> { joins(:washing_instructions).where('washing_instructions.dry_clean_only = ?', true) }
+        #   end
+        #
+        # The above calls to +scope+ define class methods <tt>Shirt.red</tt> and
+        # <tt>Shirt.dry_clean_only</tt>. <tt>Shirt.red</tt>, in effect,
+        # represents the query <tt>Shirt.where(color: 'red')</tt>.
+        #
+        # You should always pass a callable object to the scopes defined
+        # with +scope+. This ensures that the scope is re-evaluated each
+        # time it is called.
+        #
+        # Note that this is simply 'syntactic sugar' for defining an actual
+        # class method:
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     def self.red
+        #       where(color: 'red')
+        #     end
+        #   end
+        #
+        # Unlike <tt>Shirt.find(...)</tt>, however, the object returned by
+        # <tt>Shirt.red</tt> is not an Array; it resembles the association object
+        # constructed by a +has_many+ declaration. For instance, you can invoke
+        # <tt>Shirt.red.first</tt>, <tt>Shirt.red.count</tt>,
+        # <tt>Shirt.red.where(size: 'small')</tt>. Also, just as with the
+        # association objects, named \scopes act like an Array, implementing
+        # Enumerable; <tt>Shirt.red.each(&block)</tt>, <tt>Shirt.red.first</tt>,
+        # and <tt>Shirt.red.inject(memo, &block)</tt> all behave as if
+        # <tt>Shirt.red</tt> really was an Array.
+        #
+        # These named \scopes are composable. For instance,
+        # <tt>Shirt.red.dry_clean_only</tt> will produce all shirts that are
+        # both red and dry clean only. Nested finds and calculations also work
+        # with these compositions: <tt>Shirt.red.dry_clean_only.count</tt>
+        # returns the number of garments for which these criteria obtain.
+        # Similarly with <tt>Shirt.red.dry_clean_only.average(:thread_count)</tt>.
+        #
+        # All scopes are available as class methods on the ActiveRecord::Base
+        # descendant upon which the \scopes were defined. But they are also
+        # available to +has_many+ associations. If,
+        #
+        #   class Person < ActiveRecord::Base
+        #     has_many :shirts
+        #   end
+        #
+        # then <tt>elton.shirts.red.dry_clean_only</tt> will return all of
+        # Elton's red, dry clean only shirts.
+        #
+        # \Named scopes can also have extensions, just as with +has_many+
+        # declarations:
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     scope :red, -> { where(color: 'red') } do
+        #       def dom_id
+        #         'red_shirts'
+        #       end
+        #     end
+        #   end
+        #
+        # Scopes can also be used while creating/building a record.
+        #
+        #   class Article < ActiveRecord::Base
+        #     scope :published, -> { where(published: true) }
+        #   end
+        #
+        #   Article.published.new.published    # => true
+        #   Article.published.create.published # => true
+        #
+        # \Class methods on your model are automatically available
+        # on scopes. Assuming the following setup:
+        #
+        #   class Article < ActiveRecord::Base
+        #     scope :published, -> { where(published: true) }
+        #     scope :featured, -> { where(featured: true) }
+        #
+        #     def self.latest_article
+        #       order('published_at desc').first
+        #     end
+        #
+        #     def self.titles
+        #       pluck(:title)
+        #     end
+        #   end
+        #
+        # We are able to call the methods like this:
+        #
+        #   Article.published.featured.latest_article
+        #   Article.featured.titles
+        def scope(name, body, &block)
+          if dangerous_class_method?(name)
+            raise ArgumentError, "You tried to define a scope named \"#{name}\" " \
+              "on the model \"#{self.name}\", but Active Record already defined " \
+              "a class method with the same name."
+          end
+
+          extension = Module.new(&block) if block
+
+          singleton_class.send(:define_method, name) do |*args|
+            scope = all.scoping { body.call(*args) }
+            scope = scope.extending(extension) if extension
+
+            scope || all
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/serialization.rb b/activerecord/lib/active_record/serialization.rb
new file mode 100644
index 0000000000..bd9079b596
--- /dev/null
+++ b/activerecord/lib/active_record/serialization.rb
@@ -0,0 +1,22 @@
+module ActiveRecord #:nodoc:
+  # = Active Record Serialization
+  module Serialization
+    extend ActiveSupport::Concern
+    include ActiveModel::Serializers::JSON
+
+    included do
+      self.include_root_in_json = false
+    end
+
+    def serializable_hash(options = nil)
+      options = options.try(:clone) || {}
+
+      options[:except] = Array(options[:except]).map { |n| n.to_s }
+      options[:except] |= Array(self.class.inheritance_column)
+
+      super(options)
+    end
+  end
+end
+
+require 'active_record/serializers/xml_serializer'
diff --git a/activerecord/lib/active_record/serializers/xml_serializer.rb b/activerecord/lib/active_record/serializers/xml_serializer.rb
new file mode 100644
index 0000000000..c2484d02ed
--- /dev/null
+++ b/activerecord/lib/active_record/serializers/xml_serializer.rb
@@ -0,0 +1,193 @@
+require 'active_support/core_ext/hash/conversions'
+
+module ActiveRecord #:nodoc:
+  module Serialization
+    include ActiveModel::Serializers::Xml
+
+    # Builds an XML document to represent the model. Some configuration is
+    # available through +options+. However more complicated cases should
+    # override ActiveRecord::Base#to_xml.
+    #
+    # By default the generated XML document will include the processing
+    # instruction and all the object's attributes. For example:
+    #
+    #   <?xml version="1.0" encoding="UTF-8"?>
+    #   <topic>
+    #     <title>The First Topic</title>
+    #     <author-name>David</author-name>
+    #     <id type="integer">1</id>
+    #     <approved type="boolean">false</approved>
+    #     <replies-count type="integer">0</replies-count>
+    #     <bonus-time type="dateTime">2000-01-01T08:28:00+12:00</bonus-time>
+    #     <written-on type="dateTime">2003-07-16T09:28:00+1200</written-on>
+    #     <content>Have a nice day</content>
+    #     <author-email-address>david@loudthinking.com</author-email-address>
+    #     <parent-id></parent-id>
+    #     <last-read type="date">2004-04-15</last-read>
+    #   </topic>
+    #
+    # This behavior can be controlled with <tt>:only</tt>, <tt>:except</tt>,
+    # <tt>:skip_instruct</tt>, <tt>:skip_types</tt>, <tt>:dasherize</tt> and <tt>:camelize</tt> .
+    # The <tt>:only</tt> and <tt>:except</tt> options are the same as for the
+    # +attributes+ method. The default is to dasherize all column names, but you
+    # can disable this setting <tt>:dasherize</tt> to +false+. Setting <tt>:camelize</tt>
+    # to +true+ will camelize all column names - this also overrides <tt>:dasherize</tt>.
+    # To not have the column type included in the XML output set <tt>:skip_types</tt> to +true+.
+    #
+    # For instance:
+    #
+    #   topic.to_xml(skip_instruct: true, except: [ :id, :bonus_time, :written_on, :replies_count ])
+    #
+    #   <topic>
+    #     <title>The First Topic</title>
+    #     <author-name>David</author-name>
+    #     <approved type="boolean">false</approved>
+    #     <content>Have a nice day</content>
+    #     <author-email-address>david@loudthinking.com</author-email-address>
+    #     <parent-id></parent-id>
+    #     <last-read type="date">2004-04-15</last-read>
+    #   </topic>
+    #
+    # To include first level associations use <tt>:include</tt>:
+    #
+    #   firm.to_xml include: [ :account, :clients ]
+    #
+    #   <?xml version="1.0" encoding="UTF-8"?>
+    #   <firm>
+    #     <id type="integer">1</id>
+    #     <rating type="integer">1</rating>
+    #     <name>37signals</name>
+    #     <clients type="array">
+    #       <client>
+    #         <rating type="integer">1</rating>
+    #         <name>Summit</name>
+    #       </client>
+    #       <client>
+    #         <rating type="integer">1</rating>
+    #         <name>Microsoft</name>
+    #       </client>
+    #     </clients>
+    #     <account>
+    #       <id type="integer">1</id>
+    #       <credit-limit type="integer">50</credit-limit>
+    #     </account>
+    #   </firm>
+    #
+    # Additionally, the record being serialized will be passed to a Proc's second
+    # parameter. This allows for ad hoc additions to the resultant document that
+    # incorporate the context of the record being serialized. And by leveraging the
+    # closure created by a Proc, to_xml can be used to add elements that normally fall
+    # outside of the scope of the model -- for example, generating and appending URLs
+    # associated with models.
+    #
+    #   proc = Proc.new { |options, record| options[:builder].tag!('name-reverse', record.name.reverse) }
+    #   firm.to_xml procs: [ proc ]
+    #
+    #   <firm>
+    #     # ... normal attributes as shown above ...
+    #     <name-reverse>slangis73</name-reverse>
+    #   </firm>
+    #
+    # To include deeper levels of associations pass a hash like this:
+    #
+    #   firm.to_xml include: {account: {}, clients: {include: :address}}
+    #   <?xml version="1.0" encoding="UTF-8"?>
+    #   <firm>
+    #     <id type="integer">1</id>
+    #     <rating type="integer">1</rating>
+    #     <name>37signals</name>
+    #     <clients type="array">
+    #       <client>
+    #         <rating type="integer">1</rating>
+    #         <name>Summit</name>
+    #         <address>
+    #           ...
+    #         </address>
+    #       </client>
+    #       <client>
+    #         <rating type="integer">1</rating>
+    #         <name>Microsoft</name>
+    #         <address>
+    #           ...
+    #         </address>
+    #       </client>
+    #     </clients>
+    #     <account>
+    #       <id type="integer">1</id>
+    #       <credit-limit type="integer">50</credit-limit>
+    #     </account>
+    #   </firm>
+    #
+    # To include any methods on the model being called use <tt>:methods</tt>:
+    #
+    #   firm.to_xml methods: [ :calculated_earnings, :real_earnings ]
+    #
+    #   <firm>
+    #     # ... normal attributes as shown above ...
+    #     <calculated-earnings>100000000000000000</calculated-earnings>
+    #     <real-earnings>5</real-earnings>
+    #   </firm>
+    #
+    # To call any additional Procs use <tt>:procs</tt>. The Procs are passed a
+    # modified version of the options hash that was given to +to_xml+:
+    #
+    #   proc = Proc.new { |options| options[:builder].tag!('abc', 'def') }
+    #   firm.to_xml procs: [ proc ]
+    #
+    #   <firm>
+    #     # ... normal attributes as shown above ...
+    #     <abc>def</abc>
+    #   </firm>
+    #
+    # Alternatively, you can yield the builder object as part of the +to_xml+ call:
+    #
+    #   firm.to_xml do |xml|
+    #     xml.creator do
+    #       xml.first_name "David"
+    #       xml.last_name "Heinemeier Hansson"
+    #     end
+    #   end
+    #
+    #   <firm>
+    #     # ... normal attributes as shown above ...
+    #     <creator>
+    #       <first_name>David</first_name>
+    #       <last_name>Heinemeier Hansson</last_name>
+    #     </creator>
+    #   </firm>
+    #
+    # As noted above, you may override +to_xml+ in your ActiveRecord::Base
+    # subclasses to have complete control about what's generated. The general
+    # form of doing this is:
+    #
+    #   class IHaveMyOwnXML < ActiveRecord::Base
+    #     def to_xml(options = {})
+    #       require 'builder'
+    #       options[:indent] ||= 2
+    #       xml = options[:builder] ||= ::Builder::XmlMarkup.new(indent: options[:indent])
+    #       xml.instruct! unless options[:skip_instruct]
+    #       xml.level_one do
+    #         xml.tag!(:second_level, 'content')
+    #       end
+    #     end
+    #   end
+    def to_xml(options = {}, &block)
+      XmlSerializer.new(self, options).serialize(&block)
+    end
+  end
+
+  class XmlSerializer < ActiveModel::Serializers::Xml::Serializer #:nodoc:
+    class Attribute < ActiveModel::Serializers::Xml::Serializer::Attribute #:nodoc:
+      def compute_type
+        klass = @serializable.class
+        column = klass.columns_hash[name] || Type::Value.new
+
+        type = ActiveSupport::XmlMini::TYPE_NAMES[value.class.name] || column.type
+
+        { :text => :string,
+          :time => :datetime }[type] || type
+      end
+      protected :compute_type
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/statement_cache.rb b/activerecord/lib/active_record/statement_cache.rb
new file mode 100644
index 0000000000..aece446384
--- /dev/null
+++ b/activerecord/lib/active_record/statement_cache.rb
@@ -0,0 +1,100 @@
+module ActiveRecord
+
+  # Statement cache is used to cache a single statement in order to avoid creating the AST again.
+  # Initializing the cache is done by passing the statement in the initialization block:
+  #
+  #   cache = ActiveRecord::StatementCache.new do
+  #     Book.where(name: "my book").limit(100)
+  #   end
+  #
+  # The cached statement is executed by using the +execute+ method:
+  #
+  #   cache.execute
+  #
+  # The relation returned by the block is cached, and for each +execute+ call the cached relation gets duped.
+  # Database is queried when +to_a+ is called on the relation.
+  class StatementCache
+    class Substitute; end
+
+    class Query
+      def initialize(sql)
+        @sql = sql
+      end
+
+      def sql_for(binds, connection)
+        @sql
+      end
+    end
+
+    class PartialQuery < Query
+      def initialize values
+        @values = values
+        @indexes = values.each_with_index.find_all { |thing,i|
+          Arel::Nodes::BindParam === thing
+        }.map(&:last)
+      end
+
+      def sql_for(binds, connection)
+        val = @values.dup
+        binds = binds.dup
+        @indexes.each { |i| val[i] = connection.quote(*binds.shift.reverse) }
+        val.join
+      end
+    end
+
+    def self.query(visitor, ast)
+      Query.new visitor.accept(ast, Arel::Collectors::SQLString.new).value
+    end
+
+    def self.partial_query(visitor, ast, collector)
+      collected = visitor.accept(ast, collector).value
+      PartialQuery.new collected
+    end
+
+    class Params
+      def bind; Substitute.new; end
+    end
+
+    class BindMap
+      def initialize(bind_values)
+        @indexes   = []
+        @bind_values = bind_values
+
+        bind_values.each_with_index do |(_, value), i|
+          if Substitute === value
+            @indexes << i
+          end
+        end
+      end
+
+      def bind(values)
+        bvs = @bind_values.map { |pair| pair.dup }
+        @indexes.each_with_index { |offset,i| bvs[offset][1] = values[i] }
+        bvs
+      end
+    end
+
+    attr_reader :bind_map, :query_builder
+
+    def self.create(connection, block = Proc.new)
+      relation      = block.call Params.new
+      bind_map      = BindMap.new relation.bind_values
+      query_builder = connection.cacheable_query relation.arel
+      new query_builder, bind_map
+    end
+
+    def initialize(query_builder, bind_map)
+      @query_builder = query_builder
+      @bind_map      = bind_map
+    end
+
+    def execute(params, klass, connection)
+      bind_values = bind_map.bind params
+
+      sql = query_builder.sql_for bind_values, connection
+
+      klass.find_by_sql sql, bind_values
+    end
+    alias :call :execute
+  end
+end
diff --git a/activerecord/lib/active_record/store.rb b/activerecord/lib/active_record/store.rb
new file mode 100644
index 0000000000..3c291f28e3
--- /dev/null
+++ b/activerecord/lib/active_record/store.rb
@@ -0,0 +1,205 @@
+require 'active_support/core_ext/hash/indifferent_access'
+
+module ActiveRecord
+  # Store gives you a thin wrapper around serialize for the purpose of storing hashes in a single column.
+  # It's like a simple key/value store baked into your record when you don't care about being able to
+  # query that store outside the context of a single record.
+  #
+  # You can then declare accessors to this store that are then accessible just like any other attribute
+  # of the model. This is very helpful for easily exposing store keys to a form or elsewhere that's
+  # already built around just accessing attributes on the model.
+  #
+  # Make sure that you declare the database column used for the serialized store as a text, so there's
+  # plenty of room.
+  #
+  # You can set custom coder to encode/decode your serialized attributes to/from different formats.
+  # JSON, YAML, Marshal are supported out of the box. Generally it can be any wrapper that provides +load+ and +dump+.
+  #
+  # NOTE - If you are using PostgreSQL specific columns like +hstore+ or +json+ there is no need for
+  # the serialization provided by +store+. Simply use +store_accessor+ instead to generate
+  # the accessor methods. Be aware that these columns use a string keyed hash and do not allow access
+  # using a symbol.
+  #
+  # Examples:
+  #
+  #   class User < ActiveRecord::Base
+  #     store :settings, accessors: [ :color, :homepage ], coder: JSON
+  #   end
+  #
+  #   u = User.new(color: 'black', homepage: '37signals.com')
+  #   u.color                          # Accessor stored attribute
+  #   u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor
+  #
+  #   # There is no difference between strings and symbols for accessing custom attributes
+  #   u.settings[:country]  # => 'Denmark'
+  #   u.settings['country'] # => 'Denmark'
+  #
+  #   # Add additional accessors to an existing store through store_accessor
+  #   class SuperUser < User
+  #     store_accessor :settings, :privileges, :servants
+  #   end
+  #
+  # The stored attribute names can be retrieved using +stored_attributes+.
+  #
+  #   User.stored_attributes[:settings] # [:color, :homepage]
+  #
+  # == Overwriting default accessors
+  #
+  # All stored values are automatically available through accessors on the Active Record
+  # object, but sometimes you want to specialize this behavior. This can be done by overwriting
+  # the default accessors (using the same name as the attribute) and calling <tt>super</tt>
+  # to actually change things.
+  #
+  #   class Song < ActiveRecord::Base
+  #     # Uses a stored integer to hold the volume adjustment of the song
+  #     store :settings, accessors: [:volume_adjustment]
+  #
+  #     def volume_adjustment=(decibels)
+  #       super(decibels.to_i)
+  #     end
+  #
+  #     def volume_adjustment
+  #       super.to_i
+  #     end
+  #   end
+  module Store
+    extend ActiveSupport::Concern
+
+    included do
+      class << self
+        attr_accessor :local_stored_attributes
+      end
+    end
+
+    module ClassMethods
+      def store(store_attribute, options = {})
+        serialize store_attribute, IndifferentCoder.new(options[:coder])
+        store_accessor(store_attribute, options[:accessors]) if options.has_key? :accessors
+      end
+
+      def store_accessor(store_attribute, *keys)
+        keys = keys.flatten
+
+        _store_accessors_module.module_eval do
+          keys.each do |key|
+            define_method("#{key}=") do |value|
+              write_store_attribute(store_attribute, key, value)
+            end
+
+            define_method(key) do
+              read_store_attribute(store_attribute, key)
+            end
+          end
+        end
+
+        # assign new store attribute and create new hash to ensure that each class in the hierarchy
+        # has its own hash of stored attributes.
+        self.local_stored_attributes ||= {}
+        self.local_stored_attributes[store_attribute] ||= []
+        self.local_stored_attributes[store_attribute] |= keys
+      end
+
+      def _store_accessors_module # :nodoc:
+        @_store_accessors_module ||= begin
+          mod = Module.new
+          include mod
+          mod
+        end
+      end
+
+      def stored_attributes
+        parent = superclass.respond_to?(:stored_attributes) ? superclass.stored_attributes : {}
+        if self.local_stored_attributes
+          parent.merge!(self.local_stored_attributes) { |k, a, b| a | b }
+        end
+        parent
+      end
+    end
+
+    protected
+      def read_store_attribute(store_attribute, key)
+        accessor = store_accessor_for(store_attribute)
+        accessor.read(self, store_attribute, key)
+      end
+
+      def write_store_attribute(store_attribute, key, value)
+        accessor = store_accessor_for(store_attribute)
+        accessor.write(self, store_attribute, key, value)
+      end
+
+    private
+      def store_accessor_for(store_attribute)
+        type_for_attribute(store_attribute.to_s).accessor
+      end
+
+      class HashAccessor # :nodoc:
+        def self.read(object, attribute, key)
+          prepare(object, attribute)
+          object.public_send(attribute)[key]
+        end
+
+        def self.write(object, attribute, key, value)
+          prepare(object, attribute)
+          if value != read(object, attribute, key)
+            object.public_send :"#{attribute}_will_change!"
+            object.public_send(attribute)[key] = value
+          end
+        end
+
+        def self.prepare(object, attribute)
+          object.public_send :"#{attribute}=", {} unless object.send(attribute)
+        end
+      end
+
+      class StringKeyedHashAccessor < HashAccessor # :nodoc:
+        def self.read(object, attribute, key)
+          super object, attribute, key.to_s
+        end
+
+        def self.write(object, attribute, key, value)
+          super object, attribute, key.to_s, value
+        end
+      end
+
+      class IndifferentHashAccessor < ActiveRecord::Store::HashAccessor # :nodoc:
+        def self.prepare(object, store_attribute)
+          attribute = object.send(store_attribute)
+          unless attribute.is_a?(ActiveSupport::HashWithIndifferentAccess)
+            attribute = IndifferentCoder.as_indifferent_hash(attribute)
+            object.send :"#{store_attribute}=", attribute
+          end
+          attribute
+        end
+      end
+
+    class IndifferentCoder # :nodoc:
+      def initialize(coder_or_class_name)
+        @coder =
+          if coder_or_class_name.respond_to?(:load) && coder_or_class_name.respond_to?(:dump)
+            coder_or_class_name
+          else
+            ActiveRecord::Coders::YAMLColumn.new(coder_or_class_name || Object)
+          end
+      end
+
+      def dump(obj)
+        @coder.dump self.class.as_indifferent_hash(obj)
+      end
+
+      def load(yaml)
+        self.class.as_indifferent_hash(@coder.load(yaml || ''))
+      end
+
+      def self.as_indifferent_hash(obj)
+        case obj
+        when ActiveSupport::HashWithIndifferentAccess
+          obj
+        when Hash
+          obj.with_indifferent_access
+        else
+          ActiveSupport::HashWithIndifferentAccess.new
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
new file mode 100644
index 0000000000..892c78e479
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -0,0 +1,276 @@
+module ActiveRecord
+  module Tasks # :nodoc:
+    class DatabaseAlreadyExists < StandardError; end # :nodoc:
+    class DatabaseNotSupported < StandardError; end # :nodoc:
+
+    # <tt>ActiveRecord::Tasks::DatabaseTasks</tt> is a utility class, which encapsulates
+    # logic behind common tasks used to manage database and migrations.
+    #
+    # The tasks defined here are used with Rake tasks provided by Active Record.
+    #
+    # In order to use DatabaseTasks, a few config values need to be set. All the needed
+    # config values are set by Rails already, so it's necessary to do it only if you
+    # want to change the defaults or when you want to use Active Record outside of Rails
+    # (in such case after configuring the database tasks, you can also use the rake tasks
+    # defined in Active Record).
+    #
+    # The possible config values are:
+    #
+    #   * +env+: current environment (like Rails.env).
+    #   * +database_configuration+: configuration of your databases (as in +config/database.yml+).
+    #   * +db_dir+: your +db+ directory.
+    #   * +fixtures_path+: a path to fixtures directory.
+    #   * +migrations_paths+: a list of paths to directories with migrations.
+    #   * +seed_loader+: an object which will load seeds, it needs to respond to the +load_seed+ method.
+    #   * +root+: a path to the root of the application.
+    #
+    # Example usage of +DatabaseTasks+ outside Rails could look as such:
+    #
+    #   include ActiveRecord::Tasks
+    #   DatabaseTasks.database_configuration = YAML.load_file('my_database_config.yml')
+    #   DatabaseTasks.db_dir = 'db'
+    #   # other settings...
+    #
+    #   DatabaseTasks.create_current('production')
+    module DatabaseTasks
+      extend self
+
+      attr_writer :current_config, :db_dir, :migrations_paths, :fixtures_path, :root, :env, :seed_loader
+      attr_accessor :database_configuration
+
+      LOCAL_HOSTS    = ['127.0.0.1', 'localhost']
+
+      def register_task(pattern, task)
+        @tasks ||= {}
+        @tasks[pattern] = task
+      end
+
+      register_task(/mysql/,        ActiveRecord::Tasks::MySQLDatabaseTasks)
+      register_task(/postgresql/,   ActiveRecord::Tasks::PostgreSQLDatabaseTasks)
+      register_task(/sqlite/,       ActiveRecord::Tasks::SQLiteDatabaseTasks)
+
+      def db_dir
+        @db_dir ||= Rails.application.config.paths["db"].first
+      end
+
+      def migrations_paths
+        @migrations_paths ||= Rails.application.paths['db/migrate'].to_a
+      end
+
+      def fixtures_path
+        @fixtures_path ||= if ENV['FIXTURES_PATH']
+                             File.join(root, ENV['FIXTURES_PATH'])
+                           else
+                             File.join(root, 'test', 'fixtures')
+                           end
+      end
+
+      def root
+        @root ||= Rails.root
+      end
+
+      def env
+        @env ||= Rails.env
+      end
+
+      def seed_loader
+        @seed_loader ||= Rails.application
+      end
+
+      def current_config(options = {})
+        options.reverse_merge! :env => env
+        if options.has_key?(:config)
+          @current_config = options[:config]
+        else
+          @current_config ||= ActiveRecord::Base.configurations[options[:env]]
+        end
+      end
+
+      def create(*arguments)
+        configuration = arguments.first
+        class_for_adapter(configuration['adapter']).new(*arguments).create
+      rescue DatabaseAlreadyExists
+        $stderr.puts "#{configuration['database']} already exists"
+      rescue Exception => error
+        $stderr.puts error, *(error.backtrace)
+        $stderr.puts "Couldn't create database for #{configuration.inspect}"
+      end
+
+      def create_all
+        each_local_configuration { |configuration| create configuration }
+      end
+
+      def create_current(environment = env)
+        each_current_configuration(environment) { |configuration|
+          create configuration
+        }
+        ActiveRecord::Base.establish_connection(environment.to_sym)
+      end
+
+      def drop(*arguments)
+        configuration = arguments.first
+        class_for_adapter(configuration['adapter']).new(*arguments).drop
+      rescue ActiveRecord::NoDatabaseError
+        $stderr.puts "Database '#{configuration['database']}' does not exist"
+      rescue Exception => error
+        $stderr.puts error, *(error.backtrace)
+        $stderr.puts "Couldn't drop #{configuration['database']}"
+      end
+
+      def drop_all
+        each_local_configuration { |configuration| drop configuration }
+      end
+
+      def drop_current(environment = env)
+        each_current_configuration(environment) { |configuration|
+          drop configuration
+        }
+      end
+
+      def migrate
+        verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] == "true" : true
+        version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
+        scope   = ENV['SCOPE']
+        Migration.verbose = verbose
+        Migrator.migrate(Migrator.migrations_paths, version) do |migration|
+          scope.blank? || scope == migration.scope
+        end
+      end
+
+      def charset_current(environment = env)
+        charset ActiveRecord::Base.configurations[environment]
+      end
+
+      def charset(*arguments)
+        configuration = arguments.first
+        class_for_adapter(configuration['adapter']).new(*arguments).charset
+      end
+
+      def collation_current(environment = env)
+        collation ActiveRecord::Base.configurations[environment]
+      end
+
+      def collation(*arguments)
+        configuration = arguments.first
+        class_for_adapter(configuration['adapter']).new(*arguments).collation
+      end
+
+      def purge(configuration)
+        class_for_adapter(configuration['adapter']).new(configuration).purge
+      end
+
+      def purge_all
+        each_local_configuration { |configuration|
+          purge configuration
+        }
+      end
+
+      def purge_current(environment = env)
+        each_current_configuration(environment) { |configuration|
+          purge configuration
+        }
+      end
+
+      def structure_dump(*arguments)
+        configuration = arguments.first
+        filename = arguments.delete_at 1
+        class_for_adapter(configuration['adapter']).new(*arguments).structure_dump(filename)
+      end
+
+      def structure_load(*arguments)
+        configuration = arguments.first
+        filename = arguments.delete_at 1
+        class_for_adapter(configuration['adapter']).new(*arguments).structure_load(filename)
+      end
+
+      def load_schema(format = ActiveRecord::Base.schema_format, file = nil)
+        ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
+          This method will act on a specific connection in the future.
+          To act on the current connection, use `load_schema_current` instead.
+        MESSAGE
+        load_schema_current(format, file)
+      end
+
+      # This method is the successor of +load_schema+. We should rename it
+      # after +load_schema+ went through a deprecation cycle. (Rails > 4.2)
+      def load_schema_for(configuration, format = ActiveRecord::Base.schema_format, file = nil) # :nodoc:
+        case format
+        when :ruby
+          file ||= File.join(db_dir, "schema.rb")
+          check_schema_file(file)
+          purge(configuration)
+          ActiveRecord::Base.establish_connection(configuration)
+          load(file)
+        when :sql
+          file ||= File.join(db_dir, "structure.sql")
+          check_schema_file(file)
+          purge(configuration)
+          structure_load(configuration, file)
+        else
+          raise ArgumentError, "unknown format #{format.inspect}"
+        end
+      end
+
+      def load_schema_current(format = ActiveRecord::Base.schema_format, file = nil, environment = env)
+        each_current_configuration(environment) { |configuration|
+          load_schema_for configuration, format, file
+        }
+      end
+
+      def check_schema_file(filename)
+        unless File.exist?(filename)
+          message = %{#{filename} doesn't exist yet. Run `rake db:migrate` to create it, then try again.}
+          message << %{ If you do not intend to use a database, you should instead alter #{Rails.root}/config/application.rb to limit the frameworks that will be loaded.} if defined?(::Rails)
+          Kernel.abort message
+        end
+      end
+
+      def load_seed
+        if seed_loader
+          seed_loader.load_seed
+        else
+          raise "You tried to load seed data, but no seed loader is specified. Please specify seed " +
+                "loader with ActiveRecord::Tasks::DatabaseTasks.seed_loader = your_seed_loader\n" +
+                "Seed loader should respond to load_seed method"
+        end
+      end
+
+      private
+
+      def class_for_adapter(adapter)
+        key = @tasks.keys.detect { |pattern| adapter[pattern] }
+        unless key
+          raise DatabaseNotSupported, "Rake tasks not supported by '#{adapter}' adapter"
+        end
+        @tasks[key]
+      end
+
+      def each_current_configuration(environment)
+        environments = [environment]
+        # add test environment only if no RAILS_ENV was specified.
+        environments << 'test' if environment == 'development' && ENV['RAILS_ENV'].nil?
+
+        configurations = ActiveRecord::Base.configurations.values_at(*environments)
+        configurations.compact.each do |configuration|
+          yield configuration unless configuration['database'].blank?
+        end
+      end
+
+      def each_local_configuration
+        ActiveRecord::Base.configurations.each_value do |configuration|
+          next unless configuration['database']
+
+          if local_database?(configuration)
+            yield configuration
+          else
+            $stderr.puts "This task only modifies local databases. #{configuration['database']} is on a remote host."
+          end
+        end
+      end
+
+      def local_database?(configuration)
+        configuration['host'].blank? || LOCAL_HOSTS.include?(configuration['host'])
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/tasks/mysql_database_tasks.rb b/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
new file mode 100644
index 0000000000..d890196f47
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
@@ -0,0 +1,144 @@
+module ActiveRecord
+  module Tasks # :nodoc:
+    class MySQLDatabaseTasks # :nodoc:
+      DEFAULT_CHARSET     = ENV['CHARSET']   || 'utf8'
+      DEFAULT_COLLATION   = ENV['COLLATION'] || 'utf8_unicode_ci'
+      ACCESS_DENIED_ERROR = 1045
+
+      delegate :connection, :establish_connection, to: ActiveRecord::Base
+
+      def initialize(configuration)
+        @configuration = configuration
+      end
+
+      def create
+        establish_connection configuration_without_database
+        connection.create_database configuration['database'], creation_options
+        establish_connection configuration
+      rescue ActiveRecord::StatementInvalid => error
+        if /database exists/ === error.message
+          raise DatabaseAlreadyExists
+        else
+          raise
+        end
+      rescue error_class => error
+        if error.respond_to?(:errno) && error.errno == ACCESS_DENIED_ERROR
+          $stdout.print error.error
+          establish_connection root_configuration_without_database
+          connection.create_database configuration['database'], creation_options
+          if configuration['username'] != 'root'
+            connection.execute grant_statement.gsub(/\s+/, ' ').strip
+          end
+          establish_connection configuration
+        else
+          $stderr.puts "Couldn't create database for #{configuration.inspect}, #{creation_options.inspect}"
+          $stderr.puts "(If you set the charset manually, make sure you have a matching collation)" if configuration['encoding']
+        end
+      end
+
+      def drop
+        establish_connection configuration
+        connection.drop_database configuration['database']
+      end
+
+      def purge
+        establish_connection configuration
+        connection.recreate_database configuration['database'], creation_options
+      end
+
+      def charset
+        connection.charset
+      end
+
+      def collation
+        connection.collation
+      end
+
+      def structure_dump(filename)
+        args = prepare_command_options('mysqldump')
+        args.concat(["--result-file", "#{filename}"])
+        args.concat(["--no-data"])
+        args.concat(["#{configuration['database']}"])
+        unless Kernel.system(*args)
+          $stderr.puts "Could not dump the database structure. "\
+                       "Make sure `mysqldump` is in your PATH and check the command output for warnings."
+        end
+      end
+
+      def structure_load(filename)
+        args = prepare_command_options('mysql')
+        args.concat(['--execute', %{SET FOREIGN_KEY_CHECKS = 0; SOURCE #{filename}; SET FOREIGN_KEY_CHECKS = 1}])
+        args.concat(["--database", "#{configuration['database']}"])
+        Kernel.system(*args)
+      end
+
+      private
+
+      def configuration
+        @configuration
+      end
+
+      def configuration_without_database
+        configuration.merge('database' => nil)
+      end
+
+      def creation_options
+        Hash.new.tap do |options|
+          options[:charset]     = configuration['encoding']   if configuration.include? 'encoding'
+          options[:collation]   = configuration['collation']  if configuration.include? 'collation'
+
+          # Set default charset only when collation isn't set.
+          options[:charset]   ||= DEFAULT_CHARSET unless options[:collation]
+
+          # Set default collation only when charset is also default.
+          options[:collation] ||= DEFAULT_COLLATION if options[:charset] == DEFAULT_CHARSET
+        end
+      end
+
+      def error_class
+        if configuration['adapter'] =~ /jdbc/
+          require 'active_record/railties/jdbcmysql_error'
+          ArJdbcMySQL::Error
+        elsif defined?(Mysql2)
+          Mysql2::Error
+        elsif defined?(Mysql)
+          Mysql::Error
+        else
+          StandardError
+        end
+      end
+
+      def grant_statement
+        <<-SQL
+GRANT ALL PRIVILEGES ON #{configuration['database']}.*
+  TO '#{configuration['username']}'@'localhost'
+IDENTIFIED BY '#{configuration['password']}' WITH GRANT OPTION;
+        SQL
+      end
+
+      def root_configuration_without_database
+        configuration_without_database.merge(
+          'username' => 'root',
+          'password' => root_password
+        )
+      end
+
+      def root_password
+        $stdout.print "Please provide the root password for your MySQL installation\n>"
+        $stdin.gets.strip
+      end
+
+      def prepare_command_options(command)
+        args = [command]
+        args.concat(['--user', configuration['username']]) if configuration['username']
+        args << "--password=#{configuration['password']}"  if configuration['password']
+        args.concat(['--default-character-set', configuration['encoding']]) if configuration['encoding']
+        configuration.slice('host', 'port', 'socket').each do |k, v|
+          args.concat([ "--#{k}", v.to_s ]) if v
+        end
+
+        args
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
new file mode 100644
index 0000000000..ce1de4b76e
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
@@ -0,0 +1,90 @@
+require 'shellwords'
+
+module ActiveRecord
+  module Tasks # :nodoc:
+    class PostgreSQLDatabaseTasks # :nodoc:
+      DEFAULT_ENCODING = ENV['CHARSET'] || 'utf8'
+
+      delegate :connection, :establish_connection, :clear_active_connections!,
+        to: ActiveRecord::Base
+
+      def initialize(configuration)
+        @configuration = configuration
+      end
+
+      def create(master_established = false)
+        establish_master_connection unless master_established
+        connection.create_database configuration['database'],
+          configuration.merge('encoding' => encoding)
+        establish_connection configuration
+      rescue ActiveRecord::StatementInvalid => error
+        if /database .* already exists/ === error.message
+          raise DatabaseAlreadyExists
+        else
+          raise
+        end
+      end
+
+      def drop
+        establish_master_connection
+        connection.drop_database configuration['database']
+      end
+
+      def charset
+        connection.encoding
+      end
+
+      def collation
+        connection.collation
+      end
+
+      def purge
+        clear_active_connections!
+        drop
+        create true
+      end
+
+      def structure_dump(filename)
+        set_psql_env
+        search_path = configuration['schema_search_path']
+        unless search_path.blank?
+          search_path = search_path.split(",").map{|search_path_part| "--schema=#{Shellwords.escape(search_path_part.strip)}" }.join(" ")
+        end
+
+        command = "pg_dump -i -s -x -O -f #{Shellwords.escape(filename)} #{search_path} #{Shellwords.escape(configuration['database'])}"
+        raise 'Error dumping database' unless Kernel.system(command)
+
+        File.open(filename, "a") { |f| f << "SET search_path TO #{connection.schema_search_path};\n\n" }
+      end
+
+      def structure_load(filename)
+        set_psql_env
+        Kernel.system("psql -q -f #{Shellwords.escape(filename)} #{configuration['database']}")
+      end
+
+      private
+
+      def configuration
+        @configuration
+      end
+
+      def encoding
+        configuration['encoding'] || DEFAULT_ENCODING
+      end
+
+      def establish_master_connection
+        establish_connection configuration.merge(
+          'database'           => 'postgres',
+          'schema_search_path' => 'public'
+        )
+      end
+
+      def set_psql_env
+        ENV['PGHOST']     = configuration['host']          if configuration['host']
+        ENV['PGPORT']     = configuration['port'].to_s     if configuration['port']
+        ENV['PGPASSWORD'] = configuration['password'].to_s if configuration['password']
+        ENV['PGUSER']     = configuration['username'].to_s if configuration['username']
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb b/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
new file mode 100644
index 0000000000..9ab64d0325
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
@@ -0,0 +1,55 @@
+module ActiveRecord
+  module Tasks # :nodoc:
+    class SQLiteDatabaseTasks # :nodoc:
+      delegate :connection, :establish_connection, to: ActiveRecord::Base
+
+      def initialize(configuration, root = ActiveRecord::Tasks::DatabaseTasks.root)
+        @configuration, @root = configuration, root
+      end
+
+      def create
+        raise DatabaseAlreadyExists if File.exist?(configuration['database'])
+
+        establish_connection configuration
+        connection
+      end
+
+      def drop
+        require 'pathname'
+        path = Pathname.new configuration['database']
+        file = path.absolute? ? path.to_s : File.join(root, path)
+
+        FileUtils.rm(file) if File.exist?(file)
+      end
+
+      def purge
+        drop
+        create
+      end
+
+      def charset
+        connection.encoding
+      end
+
+      def structure_dump(filename)
+        dbfile = configuration['database']
+        `sqlite3 #{dbfile} .schema > #{filename}`
+      end
+
+      def structure_load(filename)
+        dbfile = configuration['database']
+        `sqlite3 #{dbfile} < "#{filename}"`
+      end
+
+      private
+
+      def configuration
+        @configuration
+      end
+
+      def root
+        @root
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
new file mode 100644
index 0000000000..ddf3e1804c
--- /dev/null
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -0,0 +1,120 @@
+module ActiveRecord
+  # = Active Record Timestamp
+  #
+  # Active Record automatically timestamps create and update operations if the
+  # table has fields named <tt>created_at/created_on</tt> or
+  # <tt>updated_at/updated_on</tt>.
+  #
+  # Timestamping can be turned off by setting:
+  #
+  #   config.active_record.record_timestamps = false
+  #
+  # Timestamps are in UTC by default but you can use the local timezone by setting:
+  #
+  #   config.active_record.default_timezone = :local
+  #
+  # == Time Zone aware attributes
+  #
+  # By default, ActiveRecord::Base keeps all the datetime columns time zone aware by executing following code.
+  #
+  #   config.active_record.time_zone_aware_attributes = true
+  #
+  # This feature can easily be turned off by assigning value <tt>false</tt> .
+  #
+  # If your attributes are time zone aware and you desire to skip time zone conversion to the current Time.zone
+  # when reading certain attributes then you can do following:
+  #
+  #   class Topic < ActiveRecord::Base
+  #     self.skip_time_zone_conversion_for_attributes = [:written_on]
+  #   end
+  module Timestamp
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :record_timestamps
+      self.record_timestamps = true
+    end
+
+    def initialize_dup(other) # :nodoc:
+      super
+      clear_timestamp_attributes
+    end
+
+  private
+
+    def _create_record
+      if self.record_timestamps
+        current_time = current_time_from_proper_timezone
+
+        all_timestamp_attributes.each do |column|
+          if respond_to?(column) && respond_to?("#{column}=") && self.send(column).nil?
+            write_attribute(column.to_s, current_time)
+          end
+        end
+      end
+
+      super
+    end
+
+    def _update_record(*args)
+      if should_record_timestamps?
+        current_time = current_time_from_proper_timezone
+
+        timestamp_attributes_for_update_in_model.each do |column|
+          column = column.to_s
+          next if attribute_changed?(column)
+          write_attribute(column, current_time)
+        end
+      end
+      super
+    end
+
+    def should_record_timestamps?
+      self.record_timestamps && (!partial_writes? || changed?)
+    end
+
+    def timestamp_attributes_for_create_in_model
+      timestamp_attributes_for_create.select { |c| self.class.column_names.include?(c.to_s) }
+    end
+
+    def timestamp_attributes_for_update_in_model
+      timestamp_attributes_for_update.select { |c| self.class.column_names.include?(c.to_s) }
+    end
+
+    def all_timestamp_attributes_in_model
+      timestamp_attributes_for_create_in_model + timestamp_attributes_for_update_in_model
+    end
+
+    def timestamp_attributes_for_update
+      [:updated_at, :updated_on]
+    end
+
+    def timestamp_attributes_for_create
+      [:created_at, :created_on]
+    end
+
+    def all_timestamp_attributes
+      timestamp_attributes_for_create + timestamp_attributes_for_update
+    end
+
+    def max_updated_column_timestamp(timestamp_names = timestamp_attributes_for_update)
+      timestamp_names
+        .map { |attr| self[attr] }
+        .compact
+        .map(&:to_time)
+        .max
+    end
+
+    def current_time_from_proper_timezone
+      self.class.default_timezone == :utc ? Time.now.utc : Time.now
+    end
+
+    # Clear attributes and changed_attributes
+    def clear_timestamp_attributes
+      all_timestamp_attributes_in_model.each do |attribute_name|
+        self[attribute_name] = nil
+        changed_attributes.delete(attribute_name)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
new file mode 100644
index 0000000000..7e4dc4c895
--- /dev/null
+++ b/activerecord/lib/active_record/transactions.rb
@@ -0,0 +1,397 @@
+module ActiveRecord
+  # See ActiveRecord::Transactions::ClassMethods for documentation.
+  module Transactions
+    extend ActiveSupport::Concern
+    ACTIONS = [:create, :destroy, :update]
+
+    included do
+      define_callbacks :commit, :rollback,
+                       terminator: ->(_, result) { result == false },
+                       scope: [:kind, :name]
+    end
+
+    # = Active Record Transactions
+    #
+    # Transactions are protective blocks where SQL statements are only permanent
+    # if they can all succeed as one atomic action. The classic example is a
+    # transfer between two accounts where you can only have a deposit if the
+    # withdrawal succeeded and vice versa. Transactions enforce the integrity of
+    # the database and guard the data against program errors or database
+    # break-downs. So basically you should use transaction blocks whenever you
+    # have a number of statements that must be executed together or not at all.
+    #
+    # For example:
+    #
+    #   ActiveRecord::Base.transaction do
+    #     david.withdrawal(100)
+    #     mary.deposit(100)
+    #   end
+    #
+    # This example will only take money from David and give it to Mary if neither
+    # +withdrawal+ nor +deposit+ raise an exception. Exceptions will force a
+    # ROLLBACK that returns the database to the state before the transaction
+    # began. Be aware, though, that the objects will _not_ have their instance
+    # data returned to their pre-transactional state.
+    #
+    # == Different Active Record classes in a single transaction
+    #
+    # Though the transaction class method is called on some Active Record class,
+    # the objects within the transaction block need not all be instances of
+    # that class. This is because transactions are per-database connection, not
+    # per-model.
+    #
+    # In this example a +balance+ record is transactionally saved even
+    # though +transaction+ is called on the +Account+ class:
+    #
+    #   Account.transaction do
+    #     balance.save!
+    #     account.save!
+    #   end
+    #
+    # The +transaction+ method is also available as a model instance method.
+    # For example, you can also do this:
+    #
+    #   balance.transaction do
+    #     balance.save!
+    #     account.save!
+    #   end
+    #
+    # == Transactions are not distributed across database connections
+    #
+    # A transaction acts on a single database connection. If you have
+    # multiple class-specific databases, the transaction will not protect
+    # interaction among them. One workaround is to begin a transaction
+    # on each class whose models you alter:
+    #
+    #   Student.transaction do
+    #     Course.transaction do
+    #       course.enroll(student)
+    #       student.units += course.units
+    #     end
+    #   end
+    #
+    # This is a poor solution, but fully distributed transactions are beyond
+    # the scope of Active Record.
+    #
+    # == +save+ and +destroy+ are automatically wrapped in a transaction
+    #
+    # Both +save+ and +destroy+ come wrapped in a transaction that ensures
+    # that whatever you do in validations or callbacks will happen under its
+    # protected cover. So you can use validations to check for values that
+    # the transaction depends on or you can raise exceptions in the callbacks
+    # to rollback, including <tt>after_*</tt> callbacks.
+    #
+    # As a consequence changes to the database are not seen outside your connection
+    # until the operation is complete. For example, if you try to update the index
+    # of a search engine in +after_save+ the indexer won't see the updated record.
+    # The +after_commit+ callback is the only one that is triggered once the update
+    # is committed. See below.
+    #
+    # == Exception handling and rolling back
+    #
+    # Also have in mind that exceptions thrown within a transaction block will
+    # be propagated (after triggering the ROLLBACK), so you should be ready to
+    # catch those in your application code.
+    #
+    # One exception is the <tt>ActiveRecord::Rollback</tt> exception, which will trigger
+    # a ROLLBACK when raised, but not be re-raised by the transaction block.
+    #
+    # *Warning*: one should not catch <tt>ActiveRecord::StatementInvalid</tt> exceptions
+    # inside a transaction block. <tt>ActiveRecord::StatementInvalid</tt> exceptions indicate that an
+    # error occurred at the database level, for example when a unique constraint
+    # is violated. On some database systems, such as PostgreSQL, database errors
+    # inside a transaction cause the entire transaction to become unusable
+    # until it's restarted from the beginning. Here is an example which
+    # demonstrates the problem:
+    #
+    #   # Suppose that we have a Number model with a unique column called 'i'.
+    #   Number.transaction do
+    #     Number.create(i: 0)
+    #     begin
+    #       # This will raise a unique constraint error...
+    #       Number.create(i: 0)
+    #     rescue ActiveRecord::StatementInvalid
+    #       # ...which we ignore.
+    #     end
+    #
+    #     # On PostgreSQL, the transaction is now unusable. The following
+    #     # statement will cause a PostgreSQL error, even though the unique
+    #     # constraint is no longer violated:
+    #     Number.create(i: 1)
+    #     # => "PGError: ERROR:  current transaction is aborted, commands
+    #     #     ignored until end of transaction block"
+    #   end
+    #
+    # One should restart the entire transaction if an
+    # <tt>ActiveRecord::StatementInvalid</tt> occurred.
+    #
+    # == Nested transactions
+    #
+    # +transaction+ calls can be nested. By default, this makes all database
+    # statements in the nested transaction block become part of the parent
+    # transaction. For example, the following behavior may be surprising:
+    #
+    #   User.transaction do
+    #     User.create(username: 'Kotori')
+    #     User.transaction do
+    #       User.create(username: 'Nemu')
+    #       raise ActiveRecord::Rollback
+    #     end
+    #   end
+    #
+    # creates both "Kotori" and "Nemu". Reason is the <tt>ActiveRecord::Rollback</tt>
+    # exception in the nested block does not issue a ROLLBACK. Since these exceptions
+    # are captured in transaction blocks, the parent block does not see it and the
+    # real transaction is committed.
+    #
+    # In order to get a ROLLBACK for the nested transaction you may ask for a real
+    # sub-transaction by passing <tt>requires_new: true</tt>. If anything goes wrong,
+    # the database rolls back to the beginning of the sub-transaction without rolling
+    # back the parent transaction. If we add it to the previous example:
+    #
+    #   User.transaction do
+    #     User.create(username: 'Kotori')
+    #     User.transaction(requires_new: true) do
+    #       User.create(username: 'Nemu')
+    #       raise ActiveRecord::Rollback
+    #     end
+    #   end
+    #
+    # only "Kotori" is created. This works on MySQL and PostgreSQL. SQLite3 version >= '3.6.8' also supports it.
+    #
+    # Most databases don't support true nested transactions. At the time of
+    # writing, the only database that we're aware of that supports true nested
+    # transactions, is MS-SQL. Because of this, Active Record emulates nested
+    # transactions by using savepoints on MySQL and PostgreSQL. See
+    # http://dev.mysql.com/doc/refman/5.6/en/savepoint.html
+    # for more information about savepoints.
+    #
+    # === Callbacks
+    #
+    # There are two types of callbacks associated with committing and rolling back transactions:
+    # +after_commit+ and +after_rollback+.
+    #
+    # +after_commit+ callbacks are called on every record saved or destroyed within a
+    # transaction immediately after the transaction is committed. +after_rollback+ callbacks
+    # are called on every record saved or destroyed within a transaction immediately after the
+    # transaction or savepoint is rolled back.
+    #
+    # These callbacks are useful for interacting with other systems since you will be guaranteed
+    # that the callback is only executed when the database is in a permanent state. For example,
+    # +after_commit+ is a good spot to put in a hook to clearing a cache since clearing it from
+    # within a transaction could trigger the cache to be regenerated before the database is updated.
+    #
+    # === Caveats
+    #
+    # If you're on MySQL, then do not use DDL operations in nested transactions
+    # blocks that are emulated with savepoints. That is, do not execute statements
+    # like 'CREATE TABLE' inside such blocks. This is because MySQL automatically
+    # releases all savepoints upon executing a DDL operation. When +transaction+
+    # is finished and tries to release the savepoint it created earlier, a
+    # database error will occur because the savepoint has already been
+    # automatically released. The following example demonstrates the problem:
+    #
+    #   Model.connection.transaction do                           # BEGIN
+    #     Model.connection.transaction(requires_new: true) do  # CREATE SAVEPOINT active_record_1
+    #       Model.connection.create_table(...)                    # active_record_1 now automatically released
+    #     end                                                     # RELEASE savepoint active_record_1
+    #                                                             # ^^^^ BOOM! database error!
+    #   end
+    #
+    # Note that "TRUNCATE" is also a MySQL DDL statement!
+    module ClassMethods
+      # See ActiveRecord::Transactions::ClassMethods for detailed documentation.
+      def transaction(options = {}, &block)
+        # See the ConnectionAdapters::DatabaseStatements#transaction API docs.
+        connection.transaction(options, &block)
+      end
+
+      # This callback is called after a record has been created, updated, or destroyed.
+      #
+      # You can specify that the callback should only be fired by a certain action with
+      # the +:on+ option:
+      #
+      #   after_commit :do_foo, on: :create
+      #   after_commit :do_bar, on: :update
+      #   after_commit :do_baz, on: :destroy
+      #
+      #   after_commit :do_foo_bar, on: [:create, :update]
+      #   after_commit :do_bar_baz, on: [:update, :destroy]
+      #
+      # Note that transactional fixtures do not play well with this feature. Please
+      # use the +test_after_commit+ gem to have these hooks fired in tests.
+      def after_commit(*args, &block)
+        set_options_for_callbacks!(args)
+        set_callback(:commit, :after, *args, &block)
+      end
+
+      # This callback is called after a create, update, or destroy are rolled back.
+      #
+      # Please check the documentation of +after_commit+ for options.
+      def after_rollback(*args, &block)
+        set_options_for_callbacks!(args)
+        set_callback(:rollback, :after, *args, &block)
+      end
+
+      private
+
+      def set_options_for_callbacks!(args)
+        options = args.last
+        if options.is_a?(Hash) && options[:on]
+          fire_on = Array(options[:on])
+          assert_valid_transaction_action(fire_on)
+          options[:if] = Array(options[:if])
+          options[:if] << "transaction_include_any_action?(#{fire_on})"
+        end
+      end
+
+      def assert_valid_transaction_action(actions)
+        if (actions - ACTIONS).any?
+          raise ArgumentError, ":on conditions for after_commit and after_rollback callbacks have to be one of #{ACTIONS.join(",")}"
+        end
+      end
+    end
+
+    # See ActiveRecord::Transactions::ClassMethods for detailed documentation.
+    def transaction(options = {}, &block)
+      self.class.transaction(options, &block)
+    end
+
+    def destroy #:nodoc:
+      with_transaction_returning_status { super }
+    end
+
+    def save(*) #:nodoc:
+      rollback_active_record_state! do
+        with_transaction_returning_status { super }
+      end
+    end
+
+    def save!(*) #:nodoc:
+      with_transaction_returning_status { super }
+    end
+
+    def touch(*) #:nodoc:
+      with_transaction_returning_status { super }
+    end
+
+    # Reset id and @new_record if the transaction rolls back.
+    def rollback_active_record_state!
+      remember_transaction_record_state
+      yield
+    rescue Exception
+      restore_transaction_record_state
+      raise
+    ensure
+      clear_transaction_record_state
+    end
+
+    # Call the +after_commit+ callbacks.
+    #
+    # Ensure that it is not called if the object was never persisted (failed create),
+    # but call it after the commit of a destroyed object.
+    def committed! #:nodoc:
+      run_callbacks :commit if destroyed? || persisted?
+    ensure
+      force_clear_transaction_record_state
+    end
+
+    # Call the +after_rollback+ callbacks. The +force_restore_state+ argument indicates if the record
+    # state should be rolled back to the beginning or just to the last savepoint.
+    def rolledback!(force_restore_state = false) #:nodoc:
+      run_callbacks :rollback
+    ensure
+      restore_transaction_record_state(force_restore_state)
+      clear_transaction_record_state
+    end
+
+    # Add the record to the current transaction so that the +after_rollback+ and +after_commit+ callbacks
+    # can be called.
+    def add_to_transaction
+      if self.class.connection.add_transaction_record(self)
+        remember_transaction_record_state
+      end
+    end
+
+    # Executes +method+ within a transaction and captures its return value as a
+    # status flag. If the status is true the transaction is committed, otherwise
+    # a ROLLBACK is issued. In any case the status flag is returned.
+    #
+    # This method is available within the context of an ActiveRecord::Base
+    # instance.
+    def with_transaction_returning_status
+      status = nil
+      self.class.transaction do
+        add_to_transaction
+        begin
+          status = yield
+        rescue ActiveRecord::Rollback
+          clear_transaction_record_state
+          status = nil
+        end
+
+        raise ActiveRecord::Rollback unless status
+      end
+      status
+    end
+
+    protected
+
+    # Save the new record state and id of a record so it can be restored later if a transaction fails.
+    def remember_transaction_record_state #:nodoc:
+      @_start_transaction_state[:id] = id
+      unless @_start_transaction_state.include?(:new_record)
+        @_start_transaction_state[:new_record] = @new_record
+      end
+      unless @_start_transaction_state.include?(:destroyed)
+        @_start_transaction_state[:destroyed] = @destroyed
+      end
+      @_start_transaction_state[:level] = (@_start_transaction_state[:level] || 0) + 1
+      @_start_transaction_state[:frozen?] = frozen?
+    end
+
+    # Clear the new record state and id of a record.
+    def clear_transaction_record_state #:nodoc:
+      @_start_transaction_state[:level] = (@_start_transaction_state[:level] || 0) - 1
+      force_clear_transaction_record_state if @_start_transaction_state[:level] < 1
+    end
+
+    # Force to clear the transaction record state.
+    def force_clear_transaction_record_state #:nodoc:
+      @_start_transaction_state.clear
+    end
+
+    # Restore the new record state and id of a record that was previously saved by a call to save_record_state.
+    def restore_transaction_record_state(force = false) #:nodoc:
+      unless @_start_transaction_state.empty?
+        transaction_level = (@_start_transaction_state[:level] || 0) - 1
+        if transaction_level < 1 || force
+          restore_state = @_start_transaction_state
+          thaw unless restore_state[:frozen?]
+          @new_record = restore_state[:new_record]
+          @destroyed  = restore_state[:destroyed]
+          write_attribute(self.class.primary_key, restore_state[:id])
+        end
+      end
+    end
+
+    # Determine if a record was created or destroyed in a transaction. State should be one of :new_record or :destroyed.
+    def transaction_record_state(state) #:nodoc:
+      @_start_transaction_state[state]
+    end
+
+    # Determine if a transaction included an action for :create, :update, or :destroy. Used in filtering callbacks.
+    def transaction_include_any_action?(actions) #:nodoc:
+      actions.any? do |action|
+        case action
+        when :create
+          transaction_record_state(:new_record)
+        when :destroy
+          destroyed?
+        when :update
+          !(transaction_record_state(:new_record) || destroyed?)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/translation.rb b/activerecord/lib/active_record/translation.rb
new file mode 100644
index 0000000000..ddcb5f2a7a
--- /dev/null
+++ b/activerecord/lib/active_record/translation.rb
@@ -0,0 +1,22 @@
+module ActiveRecord
+  module Translation
+    include ActiveModel::Translation
+
+    # Set the lookup ancestors for ActiveModel.
+    def lookup_ancestors #:nodoc:
+      klass = self
+      classes = [klass]
+      return classes if klass == ActiveRecord::Base
+
+      while klass != klass.base_class
+        classes << klass = klass.superclass
+      end
+      classes
+    end
+
+    # Set the i18n scope to overwrite ActiveModel.
+    def i18n_scope #:nodoc:
+      :activerecord
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type.rb b/activerecord/lib/active_record/type.rb
new file mode 100644
index 0000000000..f1384e0bb2
--- /dev/null
+++ b/activerecord/lib/active_record/type.rb
@@ -0,0 +1,20 @@
+require 'active_record/type/mutable'
+require 'active_record/type/numeric'
+require 'active_record/type/time_value'
+require 'active_record/type/value'
+
+require 'active_record/type/binary'
+require 'active_record/type/boolean'
+require 'active_record/type/date'
+require 'active_record/type/date_time'
+require 'active_record/type/decimal'
+require 'active_record/type/decimal_without_scale'
+require 'active_record/type/float'
+require 'active_record/type/integer'
+require 'active_record/type/serialized'
+require 'active_record/type/string'
+require 'active_record/type/text'
+require 'active_record/type/time'
+
+require 'active_record/type/type_map'
+require 'active_record/type/hash_lookup_type_map'
diff --git a/activerecord/lib/active_record/type/binary.rb b/activerecord/lib/active_record/type/binary.rb
new file mode 100644
index 0000000000..d29ff4e494
--- /dev/null
+++ b/activerecord/lib/active_record/type/binary.rb
@@ -0,0 +1,40 @@
+module ActiveRecord
+  module Type
+    class Binary < Value # :nodoc:
+      def type
+        :binary
+      end
+
+      def binary?
+        true
+      end
+
+      def type_cast(value)
+        if value.is_a?(Data)
+          value.to_s
+        else
+          super
+        end
+      end
+
+      def type_cast_for_database(value)
+        return if value.nil?
+        Data.new(super)
+      end
+
+      class Data # :nodoc:
+        def initialize(value)
+          @value = value.to_s
+        end
+
+        def to_s
+          @value
+        end
+
+        def hex
+          @value.unpack('H*')[0]
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/boolean.rb b/activerecord/lib/active_record/type/boolean.rb
new file mode 100644
index 0000000000..06dd17ed28
--- /dev/null
+++ b/activerecord/lib/active_record/type/boolean.rb
@@ -0,0 +1,19 @@
+module ActiveRecord
+  module Type
+    class Boolean < Value # :nodoc:
+      def type
+        :boolean
+      end
+
+      private
+
+      def cast_value(value)
+        if value == ''
+          nil
+        else
+          ConnectionAdapters::Column::TRUE_VALUES.include?(value)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/date.rb b/activerecord/lib/active_record/type/date.rb
new file mode 100644
index 0000000000..d90a6069b7
--- /dev/null
+++ b/activerecord/lib/active_record/type/date.rb
@@ -0,0 +1,46 @@
+module ActiveRecord
+  module Type
+    class Date < Value # :nodoc:
+      def type
+        :date
+      end
+
+      def klass
+        ::Date
+      end
+
+      def type_cast_for_schema(value)
+        "'#{value.to_s(:db)}'"
+      end
+
+      private
+
+      def cast_value(value)
+        if value.is_a?(::String)
+          return if value.empty?
+          fast_string_to_date(value) || fallback_string_to_date(value)
+        elsif value.respond_to?(:to_date)
+          value.to_date
+        else
+          value
+        end
+      end
+
+      def fast_string_to_date(string)
+        if string =~ ConnectionAdapters::Column::Format::ISO_DATE
+          new_date $1.to_i, $2.to_i, $3.to_i
+        end
+      end
+
+      def fallback_string_to_date(string)
+        new_date(*::Date._parse(string, false).values_at(:year, :mon, :mday))
+      end
+
+      def new_date(year, mon, mday)
+        if year && year != 0
+          ::Date.new(year, mon, mday) rescue nil
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/date_time.rb b/activerecord/lib/active_record/type/date_time.rb
new file mode 100644
index 0000000000..5f19608a33
--- /dev/null
+++ b/activerecord/lib/active_record/type/date_time.rb
@@ -0,0 +1,43 @@
+module ActiveRecord
+  module Type
+    class DateTime < Value # :nodoc:
+      include TimeValue
+
+      def type
+        :datetime
+      end
+
+      def type_cast_for_database(value)
+        zone_conversion_method = ActiveRecord::Base.default_timezone == :utc ? :getutc : :getlocal
+
+        if value.acts_like?(:time)
+          value.send(zone_conversion_method)
+        else
+          super
+        end
+      end
+
+      private
+
+      def cast_value(string)
+        return string unless string.is_a?(::String)
+        return if string.empty?
+
+        fast_string_to_time(string) || fallback_string_to_time(string)
+      end
+
+      # '0.123456' -> 123456
+      # '1.123456' -> 123456
+      def microseconds(time)
+        time[:sec_fraction] ? (time[:sec_fraction] * 1_000_000).to_i : 0
+      end
+
+      def fallback_string_to_time(string)
+        time_hash = ::Date._parse(string)
+        time_hash[:sec_fraction] = microseconds(time_hash)
+
+        new_time(*time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction, :offset))
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/decimal.rb b/activerecord/lib/active_record/type/decimal.rb
new file mode 100644
index 0000000000..d10778eeb6
--- /dev/null
+++ b/activerecord/lib/active_record/type/decimal.rb
@@ -0,0 +1,40 @@
+module ActiveRecord
+  module Type
+    class Decimal < Value # :nodoc:
+      include Numeric
+
+      def type
+        :decimal
+      end
+
+      def type_cast_for_schema(value)
+        value.to_s
+      end
+
+      private
+
+      def cast_value(value)
+        case value
+        when ::Float
+          BigDecimal(value, float_precision)
+        when ::Numeric, ::String
+          BigDecimal(value, precision.to_i)
+        else
+          if value.respond_to?(:to_d)
+            value.to_d
+          else
+            cast_value(value.to_s)
+          end
+        end
+      end
+
+      def float_precision
+        if precision.to_i > ::Float::DIG + 1
+          ::Float::DIG + 1
+        else
+          precision.to_i
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/decimal_without_scale.rb b/activerecord/lib/active_record/type/decimal_without_scale.rb
new file mode 100644
index 0000000000..cabdcecdd7
--- /dev/null
+++ b/activerecord/lib/active_record/type/decimal_without_scale.rb
@@ -0,0 +1,11 @@
+require 'active_record/type/integer'
+
+module ActiveRecord
+  module Type
+    class DecimalWithoutScale < Integer # :nodoc:
+      def type
+        :decimal
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/float.rb b/activerecord/lib/active_record/type/float.rb
new file mode 100644
index 0000000000..42eb44b9a9
--- /dev/null
+++ b/activerecord/lib/active_record/type/float.rb
@@ -0,0 +1,19 @@
+module ActiveRecord
+  module Type
+    class Float < Value # :nodoc:
+      include Numeric
+
+      def type
+        :float
+      end
+
+      alias type_cast_for_database type_cast
+
+      private
+
+      def cast_value(value)
+        value.to_f
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/hash_lookup_type_map.rb b/activerecord/lib/active_record/type/hash_lookup_type_map.rb
new file mode 100644
index 0000000000..bf92680268
--- /dev/null
+++ b/activerecord/lib/active_record/type/hash_lookup_type_map.rb
@@ -0,0 +1,19 @@
+module ActiveRecord
+  module Type
+    class HashLookupTypeMap < TypeMap # :nodoc:
+      delegate :key?, to: :@mapping
+
+      def lookup(type, *args)
+        @mapping.fetch(type, proc { default_value }).call(type, *args)
+      end
+
+      def fetch(type, *args, &block)
+        @mapping.fetch(type, block).call(type, *args)
+      end
+
+      def alias_type(type, alias_type)
+        register_type(type) { |_, *args| lookup(alias_type, *args) }
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/integer.rb b/activerecord/lib/active_record/type/integer.rb
new file mode 100644
index 0000000000..08477d1303
--- /dev/null
+++ b/activerecord/lib/active_record/type/integer.rb
@@ -0,0 +1,23 @@
+module ActiveRecord
+  module Type
+    class Integer < Value # :nodoc:
+      include Numeric
+
+      def type
+        :integer
+      end
+
+      alias type_cast_for_database type_cast
+
+      private
+
+      def cast_value(value)
+        case value
+        when true then 1
+        when false then 0
+        else value.to_i rescue nil
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/mutable.rb b/activerecord/lib/active_record/type/mutable.rb
new file mode 100644
index 0000000000..066617ea59
--- /dev/null
+++ b/activerecord/lib/active_record/type/mutable.rb
@@ -0,0 +1,16 @@
+module ActiveRecord
+  module Type
+    module Mutable # :nodoc:
+      def type_cast_from_user(value)
+        type_cast_from_database(type_cast_for_database(value))
+      end
+
+      # +raw_old_value+ will be the `_before_type_cast` version of the
+      # value (likely a string). +new_value+ will be the current, type
+      # cast value.
+      def changed_in_place?(raw_old_value, new_value)
+        raw_old_value != type_cast_for_database(new_value)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/numeric.rb b/activerecord/lib/active_record/type/numeric.rb
new file mode 100644
index 0000000000..fa43266504
--- /dev/null
+++ b/activerecord/lib/active_record/type/numeric.rb
@@ -0,0 +1,36 @@
+module ActiveRecord
+  module Type
+    module Numeric # :nodoc:
+      def number?
+        true
+      end
+
+      def type_cast(value)
+        value = case value
+                when true then 1
+                when false then 0
+                when ::String then value.presence
+                else value
+                end
+        super(value)
+      end
+
+      def changed?(old_value, _new_value, new_value_before_type_cast) # :nodoc:
+        super || number_to_non_number?(old_value, new_value_before_type_cast)
+      end
+
+      private
+
+      def number_to_non_number?(old_value, new_value_before_type_cast)
+        old_value != nil && non_numeric_string?(new_value_before_type_cast)
+      end
+
+      def non_numeric_string?(value)
+        # 'wibble'.to_i will give zero, we want to make sure
+        # that we aren't marking int zero to string zero as
+        # changed.
+        value.to_s !~ /\A\d+\.?\d*\z/
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/serialized.rb b/activerecord/lib/active_record/type/serialized.rb
new file mode 100644
index 0000000000..abeea769c4
--- /dev/null
+++ b/activerecord/lib/active_record/type/serialized.rb
@@ -0,0 +1,51 @@
+module ActiveRecord
+  module Type
+    class Serialized < SimpleDelegator # :nodoc:
+      include Mutable
+
+      attr_reader :subtype, :coder
+
+      def initialize(subtype, coder)
+        @subtype = subtype
+        @coder = coder
+        super(subtype)
+      end
+
+      def type_cast_from_database(value)
+        if default_value?(value)
+          value
+        else
+          coder.load(super)
+        end
+      end
+
+      def type_cast_for_database(value)
+        return if value.nil?
+        unless default_value?(value)
+          super coder.dump(value)
+        end
+      end
+
+      def accessor
+        ActiveRecord::Store::IndifferentHashAccessor
+      end
+
+      def init_with(coder)
+        @subtype = coder['subtype']
+        @coder = coder['coder']
+        __setobj__(@subtype)
+      end
+
+      def encode_with(coder)
+        coder['subtype'] = @subtype
+        coder['coder'] = @coder
+      end
+
+      private
+
+      def default_value?(value)
+        value == coder.load(nil)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/string.rb b/activerecord/lib/active_record/type/string.rb
new file mode 100644
index 0000000000..150defb106
--- /dev/null
+++ b/activerecord/lib/active_record/type/string.rb
@@ -0,0 +1,36 @@
+module ActiveRecord
+  module Type
+    class String < Value # :nodoc:
+      def type
+        :string
+      end
+
+      def changed_in_place?(raw_old_value, new_value)
+        if new_value.is_a?(::String)
+          raw_old_value != new_value
+        end
+      end
+
+      def type_cast_for_database(value)
+        case value
+        when ::Numeric, ActiveSupport::Duration then value.to_s
+        when ::String then ::String.new(value)
+        when true then "1"
+        when false then "0"
+        else super
+        end
+      end
+
+      private
+
+      def cast_value(value)
+        case value
+        when true then "1"
+        when false then "0"
+        # String.new is slightly faster than dup
+        else ::String.new(value.to_s)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/text.rb b/activerecord/lib/active_record/type/text.rb
new file mode 100644
index 0000000000..26f980f060
--- /dev/null
+++ b/activerecord/lib/active_record/type/text.rb
@@ -0,0 +1,11 @@
+require 'active_record/type/string'
+
+module ActiveRecord
+  module Type
+    class Text < String # :nodoc:
+      def type
+        :text
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/time.rb b/activerecord/lib/active_record/type/time.rb
new file mode 100644
index 0000000000..41f7d97f0c
--- /dev/null
+++ b/activerecord/lib/active_record/type/time.rb
@@ -0,0 +1,26 @@
+module ActiveRecord
+  module Type
+    class Time < Value # :nodoc:
+      include TimeValue
+
+      def type
+        :time
+      end
+
+      private
+
+      def cast_value(value)
+        return value unless value.is_a?(::String)
+        return if value.empty?
+
+        dummy_time_value = "2000-01-01 #{value}"
+
+        fast_string_to_time(dummy_time_value) || begin
+          time_hash = ::Date._parse(dummy_time_value)
+          return if time_hash[:hour].nil?
+          new_time(*time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction))
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/time_value.rb b/activerecord/lib/active_record/type/time_value.rb
new file mode 100644
index 0000000000..d611d72dd4
--- /dev/null
+++ b/activerecord/lib/active_record/type/time_value.rb
@@ -0,0 +1,38 @@
+module ActiveRecord
+  module Type
+    module TimeValue # :nodoc:
+      def klass
+        ::Time
+      end
+
+      def type_cast_for_schema(value)
+        "'#{value.to_s(:db)}'"
+      end
+
+      private
+
+      def new_time(year, mon, mday, hour, min, sec, microsec, offset = nil)
+        # Treat 0000-00-00 00:00:00 as nil.
+        return if year.nil? || (year == 0 && mon == 0 && mday == 0)
+
+        if offset
+          time = ::Time.utc(year, mon, mday, hour, min, sec, microsec) rescue nil
+          return unless time
+
+          time -= offset
+          Base.default_timezone == :utc ? time : time.getlocal
+        else
+          ::Time.public_send(Base.default_timezone, year, mon, mday, hour, min, sec, microsec) rescue nil
+        end
+      end
+
+      # Doesn't handle time zones.
+      def fast_string_to_time(string)
+        if string =~ ConnectionAdapters::Column::Format::ISO_DATETIME
+          microsec = ($7.to_r * 1_000_000).to_i
+          new_time $1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, microsec
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/type_map.rb b/activerecord/lib/active_record/type/type_map.rb
new file mode 100644
index 0000000000..88c5f9c497
--- /dev/null
+++ b/activerecord/lib/active_record/type/type_map.rb
@@ -0,0 +1,48 @@
+module ActiveRecord
+  module Type
+    class TypeMap # :nodoc:
+      def initialize
+        @mapping = {}
+      end
+
+      def lookup(lookup_key, *args)
+        matching_pair = @mapping.reverse_each.detect do |key, _|
+          key === lookup_key
+        end
+
+        if matching_pair
+          matching_pair.last.call(lookup_key, *args)
+        else
+          default_value
+        end
+      end
+
+      def register_type(key, value = nil, &block)
+        raise ::ArgumentError unless value || block
+
+        if block
+          @mapping[key] = block
+        else
+          @mapping[key] = proc { value }
+        end
+      end
+
+      def alias_type(key, target_key)
+        register_type(key) do |sql_type, *args|
+          metadata = sql_type[/\(.*\)/, 0]
+          lookup("#{target_key}#{metadata}", *args)
+        end
+      end
+
+      def clear
+        @mapping.clear
+      end
+
+      private
+
+      def default_value
+        @default_value ||= Value.new
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/value.rb b/activerecord/lib/active_record/type/value.rb
new file mode 100644
index 0000000000..e0a783fb45
--- /dev/null
+++ b/activerecord/lib/active_record/type/value.rb
@@ -0,0 +1,94 @@
+module ActiveRecord
+  module Type
+    class Value # :nodoc:
+      attr_reader :precision, :scale, :limit
+
+      # Valid options are +precision+, +scale+, and +limit+. They are only
+      # used when dumping schema.
+      def initialize(options = {})
+        options.assert_valid_keys(:precision, :scale, :limit)
+        @precision = options[:precision]
+        @scale = options[:scale]
+        @limit = options[:limit]
+      end
+
+      # The simplified type that this object represents. Returns a symbol such
+      # as +:string+ or +:integer+
+      def type; end
+
+      # Type casts a string from the database into the appropriate ruby type.
+      # Classes which do not need separate type casting behavior for database
+      # and user provided values should override +cast_value+ instead.
+      def type_cast_from_database(value)
+        type_cast(value)
+      end
+
+      # Type casts a value from user input (e.g. from a setter). This value may
+      # be a string from the form builder, or an already type cast value
+      # provided manually to a setter.
+      #
+      # Classes which do not need separate type casting behavior for database
+      # and user provided values should override +type_cast+ or +cast_value+
+      # instead.
+      def type_cast_from_user(value)
+        type_cast(value)
+      end
+
+      # Cast a value from the ruby type to a type that the database knows how
+      # to understand. The returned value from this method should be a
+      # +String+, +Numeric+, +Date+, +Time+, +Symbol+, +true+, +false+, or
+      # +nil+
+      def type_cast_for_database(value)
+        value
+      end
+
+      # Type cast a value for schema dumping. This method is private, as we are
+      # hoping to remove it entirely.
+      def type_cast_for_schema(value) # :nodoc:
+        value.inspect
+      end
+
+      # These predicates are not documented, as I need to look further into
+      # their use, and see if they can be removed entirely.
+      def number? # :nodoc:
+        false
+      end
+
+      def binary? # :nodoc:
+        false
+      end
+
+      def klass # :nodoc:
+      end
+
+      # Determines whether a value has changed for dirty checking. +old_value+
+      # and +new_value+ will always be type-cast. Types should not need to
+      # override this method.
+      def changed?(old_value, new_value, _new_value_before_type_cast)
+        old_value != new_value
+      end
+
+      # Determines whether the mutable value has been modified since it was
+      # read. Returns +false+ by default. This method should not need to be
+      # overriden directly. Types which return a mutable value should include
+      # +Type::Mutable+, which will define this method.
+      def changed_in_place?(*)
+        false
+      end
+
+      private
+
+      def type_cast(value)
+        cast_value(value) unless value.nil?
+      end
+
+      # Convenience method for types which do not need separate type casting
+      # behavior for user and database inputs. Called by
+      # `type_cast_from_database` and `type_cast_from_user` for all values
+      # except `nil`.
+      def cast_value(value) # :doc:
+        value
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
new file mode 100644
index 0000000000..7f7d49cdb4
--- /dev/null
+++ b/activerecord/lib/active_record/validations.rb
@@ -0,0 +1,89 @@
+module ActiveRecord
+  # = Active Record RecordInvalid
+  #
+  # Raised by <tt>save!</tt> and <tt>create!</tt> when the record is invalid. Use the
+  # +record+ method to retrieve the record which did not validate.
+  #
+  #   begin
+  #     complex_operation_that_calls_save!_internally
+  #   rescue ActiveRecord::RecordInvalid => invalid
+  #     puts invalid.record.errors
+  #   end
+  class RecordInvalid < ActiveRecordError
+    attr_reader :record # :nodoc:
+    def initialize(record) # :nodoc:
+      @record = record
+      errors = @record.errors.full_messages.join(", ")
+      super(I18n.t(:"#{@record.class.i18n_scope}.errors.messages.record_invalid", :errors => errors, :default => :"errors.messages.record_invalid"))
+    end
+  end
+
+  # = Active Record Validations
+  #
+  # Active Record includes the majority of its validations from <tt>ActiveModel::Validations</tt>
+  # all of which accept the <tt>:on</tt> argument to define the context where the
+  # validations are active. Active Record will always supply either the context of
+  # <tt>:create</tt> or <tt>:update</tt> dependent on whether the model is a
+  # <tt>new_record?</tt>.
+  module Validations
+    extend ActiveSupport::Concern
+    include ActiveModel::Validations
+
+    # The validation process on save can be skipped by passing <tt>validate: false</tt>.
+    # The regular Base#save method is replaced with this when the validations
+    # module is mixed in, which it is by default.
+    def save(options={})
+      perform_validations(options) ? super : false
+    end
+
+    # Attempts to save the record just like Base#save but will raise a +RecordInvalid+
+    # exception instead of returning +false+ if the record is not valid.
+    def save!(options={})
+      perform_validations(options) ? super : raise_record_invalid
+    end
+
+    # Runs all the validations within the specified context. Returns +true+ if
+    # no errors are found, +false+ otherwise.
+    #
+    # Aliased as validate.
+    #
+    # If the argument is +false+ (default is +nil+), the context is set to <tt>:create</tt> if
+    # <tt>new_record?</tt> is +true+, and to <tt>:update</tt> if it is not.
+    #
+    # Validations with no <tt>:on</tt> option will run no matter the context. Validations with
+    # some <tt>:on</tt> option will only run in the specified context.
+    def valid?(context = nil)
+      context ||= (new_record? ? :create : :update)
+      output = super(context)
+      errors.empty? && output
+    end
+
+    alias_method :validate, :valid?
+
+    # Runs all the validations within the specified context. Returns +true+ if
+    # no errors are found, raises +RecordInvalid+ otherwise.
+    #
+    # If the argument is +false+ (default is +nil+), the context is set to <tt>:create</tt> if
+    # <tt>new_record?</tt> is +true+, and to <tt>:update</tt> if it is not.
+    #
+    # Validations with no <tt>:on</tt> option will run no matter the context. Validations with
+    # some <tt>:on</tt> option will only run in the specified context.
+    def validate!(context = nil)
+      valid?(context) || raise_record_invalid
+    end
+
+  protected
+
+    def raise_record_invalid
+      raise(RecordInvalid.new(self))
+    end
+
+    def perform_validations(options={}) # :nodoc:
+      options[:validate] == false || valid?(options[:context])
+    end
+  end
+end
+
+require "active_record/validations/associated"
+require "active_record/validations/uniqueness"
+require "active_record/validations/presence"
diff --git a/activerecord/lib/active_record/validations/associated.rb b/activerecord/lib/active_record/validations/associated.rb
new file mode 100644
index 0000000000..b4785d3ba4
--- /dev/null
+++ b/activerecord/lib/active_record/validations/associated.rb
@@ -0,0 +1,49 @@
+module ActiveRecord
+  module Validations
+    class AssociatedValidator < ActiveModel::EachValidator #:nodoc:
+      def validate_each(record, attribute, value)
+        if Array.wrap(value).reject {|r| r.marked_for_destruction? || r.valid?}.any?
+          record.errors.add(attribute, :invalid, options.merge(:value => value))
+        end
+      end
+    end
+
+    module ClassMethods
+      # Validates whether the associated object or objects are all valid.
+      # Works with any kind of association.
+      #
+      #   class Book < ActiveRecord::Base
+      #     has_many :pages
+      #     belongs_to :library
+      #
+      #     validates_associated :pages, :library
+      #   end
+      #
+      # WARNING: This validation must not be used on both ends of an association.
+      # Doing so will lead to a circular dependency and cause infinite recursion.
+      #
+      # NOTE: This validation will not fail if the association hasn't been
+      # assigned. If you want to ensure that the association is both present and
+      # guaranteed to be valid, you also need to use +validates_presence_of+.
+      #
+      # Configuration options:
+      #
+      # * <tt>:message</tt> - A custom error message (default is: "is invalid").
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
+      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to
+      #   determine if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
+      #   method, proc or string should return or evaluate to a +true+ or +false+
+      #   value.
+      def validates_associated(*attr_names)
+        validates_with AssociatedValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations/presence.rb b/activerecord/lib/active_record/validations/presence.rb
new file mode 100644
index 0000000000..e586744818
--- /dev/null
+++ b/activerecord/lib/active_record/validations/presence.rb
@@ -0,0 +1,65 @@
+module ActiveRecord
+  module Validations
+    class PresenceValidator < ActiveModel::Validations::PresenceValidator # :nodoc:
+      def validate(record)
+        super
+        attributes.each do |attribute|
+          next unless record.class._reflect_on_association(attribute)
+          associated_records = Array.wrap(record.send(attribute))
+
+          # Superclass validates presence. Ensure present records aren't about to be destroyed.
+          if associated_records.present? && associated_records.all? { |r| r.marked_for_destruction? }
+            record.errors.add(attribute, :blank, options)
+          end
+        end
+      end
+    end
+
+    module ClassMethods
+      # Validates that the specified attributes are not blank (as defined by
+      # Object#blank?), and, if the attribute is an association, that the
+      # associated object is not marked for destruction. Happens by default
+      # on save.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_one :face
+      #     validates_presence_of :face
+      #   end
+      #
+      # The face attribute must be in the object and it cannot be blank or marked
+      # for destruction.
+      #
+      # If you want to validate the presence of a boolean field (where the real values
+      # are true and false), you will want to use
+      # <tt>validates_inclusion_of :field_name, in: [true, false]</tt>.
+      #
+      # This is due to the way Object#blank? handles boolean values:
+      # <tt>false.blank? # => true</tt>.
+      #
+      # This validator defers to the ActiveModel validation for presence, adding the
+      # check to see that an associated object is not marked for destruction. This
+      # prevents the parent object from validating successfully and saving, which then
+      # deletes the associated object, thus putting the parent object into an invalid
+      # state.
+      #
+      # Configuration options:
+      # * <tt>:message</tt> - A custom error message (default is: "can't be blank").
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine if
+      #   the validation should occur (e.g. <tt>if: :allow_validation</tt>, or
+      #   <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method, proc
+      #   or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:strict</tt> - Specifies whether validation should be strict.
+      #   See <tt>ActiveModel::Validation#validates!</tt> for more information.
+      def validates_presence_of(*attr_names)
+        validates_with PresenceValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
new file mode 100644
index 0000000000..2dba4c7b94
--- /dev/null
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -0,0 +1,229 @@
+module ActiveRecord
+  module Validations
+    class UniquenessValidator < ActiveModel::EachValidator # :nodoc:
+      def initialize(options)
+        if options[:conditions] && !options[:conditions].respond_to?(:call)
+          raise ArgumentError, "#{options[:conditions]} was passed as :conditions but is not callable. " \
+                               "Pass a callable instead: `conditions: -> { where(approved: true) }`"
+        end
+        super({ case_sensitive: true }.merge!(options))
+        @klass = options[:class]
+      end
+
+      def validate_each(record, attribute, value)
+        finder_class = find_finder_class_for(record)
+        table = finder_class.arel_table
+        value = map_enum_attribute(finder_class, attribute, value)
+
+        relation = build_relation(finder_class, table, attribute, value)
+        relation = relation.and(table[finder_class.primary_key.to_sym].not_eq(record.id)) if record.persisted?
+        relation = scope_relation(record, table, relation)
+        relation = finder_class.unscoped.where(relation)
+        relation = relation.merge(options[:conditions]) if options[:conditions]
+
+        if relation.exists?
+          error_options = options.except(:case_sensitive, :scope, :conditions)
+          error_options[:value] = value
+
+          record.errors.add(attribute, :taken, error_options)
+        end
+      end
+
+    protected
+      # The check for an existing value should be run from a class that
+      # isn't abstract. This means working down from the current class
+      # (self), to the first non-abstract class. Since classes don't know
+      # their subclasses, we have to build the hierarchy between self and
+      # the record's class.
+      def find_finder_class_for(record) #:nodoc:
+        class_hierarchy = [record.class]
+
+        while class_hierarchy.first != @klass
+          class_hierarchy.unshift(class_hierarchy.first.superclass)
+        end
+
+        class_hierarchy.detect { |klass| !klass.abstract_class? }
+      end
+
+      def build_relation(klass, table, attribute, value) #:nodoc:
+        if reflection = klass._reflect_on_association(attribute)
+          attribute = reflection.foreign_key
+          value = value.attributes[reflection.klass.primary_key] unless value.nil?
+        end
+
+        attribute_name = attribute.to_s
+
+        # the attribute may be an aliased attribute
+        if klass.attribute_aliases[attribute_name]
+          attribute = klass.attribute_aliases[attribute_name]
+          attribute_name = attribute.to_s
+        end
+
+        column = klass.columns_hash[attribute_name]
+        value  = klass.connection.type_cast(value, column)
+        if value.is_a?(String) && column.limit
+          value = value.to_s[0, column.limit]
+        end
+
+        if !options[:case_sensitive] && value.is_a?(String)
+          # will use SQL LOWER function before comparison, unless it detects a case insensitive collation
+          klass.connection.case_insensitive_comparison(table, attribute, column, value)
+        else
+          klass.connection.case_sensitive_comparison(table, attribute, column, value)
+        end
+      end
+
+      def scope_relation(record, table, relation)
+        Array(options[:scope]).each do |scope_item|
+          if reflection = record.class._reflect_on_association(scope_item)
+            scope_value = record.send(reflection.foreign_key)
+            scope_item  = reflection.foreign_key
+          else
+            scope_value = record.read_attribute(scope_item)
+          end
+          relation = relation.and(table[scope_item].eq(scope_value))
+        end
+
+        relation
+      end
+
+      def map_enum_attribute(klass, attribute, value)
+        mapping = klass.defined_enums[attribute.to_s]
+        value = mapping[value] if value && mapping
+        value
+      end
+    end
+
+    module ClassMethods
+      # Validates whether the value of the specified attributes are unique
+      # across the system. Useful for making sure that only one user
+      # can be named "davidhh".
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_uniqueness_of :user_name
+      #   end
+      #
+      # It can also validate whether the value of the specified attributes are
+      # unique based on a <tt>:scope</tt> parameter:
+      #
+      #   class Person < ActiveRecord::Base
+      #     validates_uniqueness_of :user_name, scope: :account_id
+      #   end
+      #
+      # Or even multiple scope parameters. For example, making sure that a
+      # teacher can only be on the schedule once per semester for a particular
+      # class.
+      #
+      #   class TeacherSchedule < ActiveRecord::Base
+      #     validates_uniqueness_of :teacher_id, scope: [:semester_id, :class_id]
+      #   end
+      #
+      # It is also possible to limit the uniqueness constraint to a set of
+      # records matching certain conditions. In this example archived articles
+      # are not being taken into consideration when validating uniqueness
+      # of the title attribute:
+      #
+      #   class Article < ActiveRecord::Base
+      #     validates_uniqueness_of :title, conditions: -> { where.not(status: 'archived') }
+      #   end
+      #
+      # When the record is created, a check is performed to make sure that no
+      # record exists in the database with the given value for the specified
+      # attribute (that maps to a column). When the record is updated,
+      # the same check is made but disregarding the record itself.
+      #
+      # Configuration options:
+      #
+      # * <tt>:message</tt> - Specifies a custom error message (default is:
+      #   "has already been taken").
+      # * <tt>:scope</tt> - One or more columns by which to limit the scope of
+      #   the uniqueness constraint.
+      # * <tt>:conditions</tt> - Specify the conditions to be included as a
+      #   <tt>WHERE</tt> SQL fragment to limit the uniqueness constraint lookup
+      #   (e.g. <tt>conditions: -> { where(status: 'active') }</tt>).
+      # * <tt>:case_sensitive</tt> - Looks for an exact match. Ignored by
+      #   non-text columns (+true+ by default).
+      # * <tt>:allow_nil</tt> - If set to +true+, skips this validation if the
+      #   attribute is +nil+ (default is +false+).
+      # * <tt>:allow_blank</tt> - If set to +true+, skips this validation if the
+      #   attribute is blank (default is +false+).
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
+      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
+      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
+      #   proc or string should return or evaluate to a +true+ or +false+ value.
+      # * <tt>:unless</tt> - Specifies a method, proc or string to call to
+      #   determine if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
+      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
+      #   method, proc or string should return or evaluate to a +true+ or +false+
+      #   value.
+      #
+      # === Concurrency and integrity
+      #
+      # Using this validation method in conjunction with ActiveRecord::Base#save
+      # does not guarantee the absence of duplicate record insertions, because
+      # uniqueness checks on the application level are inherently prone to race
+      # conditions. For example, suppose that two users try to post a Comment at
+      # the same time, and a Comment's title must be unique. At the database-level,
+      # the actions performed by these users could be interleaved in the following manner:
+      #
+      #               User 1                 |               User 2
+      #  ------------------------------------+--------------------------------------
+      #  # User 1 checks whether there's     |
+      #  # already a comment with the title  |
+      #  # 'My Post'. This is not the case.  |
+      #  SELECT * FROM comments              |
+      #  WHERE title = 'My Post'             |
+      #                                      |
+      #                                      | # User 2 does the same thing and also
+      #                                      | # infers that their title is unique.
+      #                                      | SELECT * FROM comments
+      #                                      | WHERE title = 'My Post'
+      #                                      |
+      #  # User 1 inserts their comment.     |
+      #  INSERT INTO comments                |
+      #  (title, content) VALUES             |
+      #  ('My Post', 'hi!')                  |
+      #                                      |
+      #                                      | # User 2 does the same thing.
+      #                                      | INSERT INTO comments
+      #                                      | (title, content) VALUES
+      #                                      | ('My Post', 'hello!')
+      #                                      |
+      #                                      | # ^^^^^^
+      #                                      | # Boom! We now have a duplicate
+      #                                      | # title!
+      #
+      # This could even happen if you use transactions with the 'serializable'
+      # isolation level. The best way to work around this problem is to add a unique
+      # index to the database table using
+      # ActiveRecord::ConnectionAdapters::SchemaStatements#add_index. In the
+      # rare case that a race condition occurs, the database will guarantee
+      # the field's uniqueness.
+      #
+      # When the database catches such a duplicate insertion,
+      # ActiveRecord::Base#save will raise an ActiveRecord::StatementInvalid
+      # exception. You can either choose to let this error propagate (which
+      # will result in the default Rails exception page being shown), or you
+      # can catch it and restart the transaction (e.g. by telling the user
+      # that the title already exists, and asking them to re-enter the title).
+      # This technique is also known as
+      # {optimistic concurrency control}[http://en.wikipedia.org/wiki/Optimistic_concurrency_control].
+      #
+      # The bundled ActiveRecord::ConnectionAdapters distinguish unique index
+      # constraint errors from other types of database errors by throwing an
+      # ActiveRecord::RecordNotUnique exception. For other adapters you will
+      # have to parse the (database-specific) exception message to detect such
+      # a case.
+      #
+      # The following bundled adapters throw the ActiveRecord::RecordNotUnique exception:
+      #
+      # * ActiveRecord::ConnectionAdapters::MysqlAdapter.
+      # * ActiveRecord::ConnectionAdapters::Mysql2Adapter.
+      # * ActiveRecord::ConnectionAdapters::SQLite3Adapter.
+      # * ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.
+      def validates_uniqueness_of(*attr_names)
+        validates_with UniquenessValidator, _merge_attributes(attr_names)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/version.rb b/activerecord/lib/active_record/version.rb
new file mode 100644
index 0000000000..cf76a13b44
--- /dev/null
+++ b/activerecord/lib/active_record/version.rb
@@ -0,0 +1,8 @@
+require_relative 'gem_version'
+
+module ActiveRecord
+  # Returns the version of the currently loaded ActiveRecord as a <tt>Gem::Version</tt>
+  def self.version
+    gem_version
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record.rb b/activerecord/lib/rails/generators/active_record.rb
new file mode 100644
index 0000000000..dc29213235
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record.rb
@@ -0,0 +1,17 @@
+require 'rails/generators/named_base'
+require 'rails/generators/active_model'
+require 'rails/generators/active_record/migration'
+require 'active_record'
+
+module ActiveRecord
+  module Generators # :nodoc:
+    class Base < Rails::Generators::NamedBase # :nodoc:
+      include ActiveRecord::Generators::Migration
+
+      # Set the current directory as base for the inherited generators.
+      def self.base_root
+        File.dirname(__FILE__)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/migration.rb b/activerecord/lib/rails/generators/active_record/migration.rb
new file mode 100644
index 0000000000..b7418cf42f
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/migration.rb
@@ -0,0 +1,18 @@
+require 'rails/generators/migration'
+
+module ActiveRecord
+  module Generators # :nodoc:
+    module Migration
+      extend ActiveSupport::Concern
+      include Rails::Generators::Migration
+
+      module ClassMethods
+        # Implement the required interface for Rails::Generators::Migration.
+        def next_migration_number(dirname)
+          next_migration_number = current_migration_number(dirname) + 1
+          ActiveRecord::Migration.next_migration_number(next_migration_number)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb b/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
new file mode 100644
index 0000000000..d3c853cfea
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
@@ -0,0 +1,70 @@
+require 'rails/generators/active_record'
+
+module ActiveRecord
+  module Generators # :nodoc:
+    class MigrationGenerator < Base # :nodoc:
+      argument :attributes, :type => :array, :default => [], :banner => "field[:type][:index] field[:type][:index]"
+
+      def create_migration_file
+        set_local_assigns!
+        validate_file_name!
+        migration_template @migration_template, "db/migrate/#{file_name}.rb"
+      end
+
+      protected
+      attr_reader :migration_action, :join_tables
+
+      # sets the default migration template that is being used for the generation of the migration
+      # depending on the arguments which would be sent out in the command line, the migration template 
+      # and the table name instance variables are setup.
+
+      def set_local_assigns!
+        @migration_template = "migration.rb"
+        case file_name
+        when /^(add|remove)_.*_(?:to|from)_(.*)/
+          @migration_action = $1
+          @table_name       = normalize_table_name($2)
+        when /join_table/
+          if attributes.length == 2
+            @migration_action = 'join'
+            @join_tables      = pluralize_table_names? ? attributes.map(&:plural_name) : attributes.map(&:singular_name)
+
+            set_index_names
+          end
+        when /^create_(.+)/
+          @table_name = normalize_table_name($1)
+          @migration_template = "create_table_migration.rb"
+        end
+      end
+
+      def set_index_names
+        attributes.each_with_index do |attr, i|
+          attr.index_name = [attr, attributes[i - 1]].map{ |a| index_name_for(a) }
+        end
+      end
+
+      def index_name_for(attribute)
+        if attribute.foreign_key?
+          attribute.name
+        else
+          attribute.name.singularize.foreign_key
+        end.to_sym
+      end
+
+      private
+        def attributes_with_index
+          attributes.select { |a| !a.reference? && a.has_index? }
+        end
+        
+        def validate_file_name!
+          unless file_name =~ /^[_a-z0-9]+$/
+            raise IllegalMigrationNameError.new(file_name)
+          end
+        end
+
+        def normalize_table_name(_table_name)
+          pluralize_table_names? ? _table_name.pluralize : _table_name.singularize
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/migration/templates/create_table_migration.rb b/activerecord/lib/rails/generators/active_record/migration/templates/create_table_migration.rb
new file mode 100644
index 0000000000..fd94a2d038
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/migration/templates/create_table_migration.rb
@@ -0,0 +1,19 @@
+class <%= migration_class_name %> < ActiveRecord::Migration
+  def change
+    create_table :<%= table_name %> do |t|
+<% attributes.each do |attribute| -%>
+<% if attribute.password_digest? -%>
+      t.string :password_digest<%= attribute.inject_options %>
+<% else -%>
+      t.<%= attribute.type %> :<%= attribute.name %><%= attribute.inject_options %>
+<% end -%>
+<% end -%>
+<% if options[:timestamps] %>
+      t.timestamps
+<% end -%>
+    end
+<% attributes_with_index.each do |attribute| -%>
+    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
+<% end -%>
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb b/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
new file mode 100644
index 0000000000..ae9c74fd05
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
@@ -0,0 +1,39 @@
+class <%= migration_class_name %> < ActiveRecord::Migration
+<%- if migration_action == 'add' -%>
+  def change
+<% attributes.each do |attribute| -%>
+  <%- if attribute.reference? -%>
+    add_reference :<%= table_name %>, :<%= attribute.name %><%= attribute.inject_options %>
+  <%- else -%>
+    add_column :<%= table_name %>, :<%= attribute.name %>, :<%= attribute.type %><%= attribute.inject_options %>
+    <%- if attribute.has_index? -%>
+    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
+    <%- end -%>
+  <%- end -%>
+<%- end -%>
+  end
+<%- elsif migration_action == 'join' -%>
+  def change
+    create_join_table :<%= join_tables.first %>, :<%= join_tables.second %> do |t|
+    <%- attributes.each do |attribute| -%>
+      <%= '# ' unless attribute.has_index? -%>t.index <%= attribute.index_name %><%= attribute.inject_index_options %>
+    <%- end -%>
+    end
+  end
+<%- else -%>
+  def change
+<% attributes.each do |attribute| -%>
+<%- if migration_action -%>
+  <%- if attribute.reference? -%>
+    remove_reference :<%= table_name %>, :<%= attribute.name %><%= attribute.inject_options %>
+  <%- else -%>
+    <%- if attribute.has_index? -%>
+    remove_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
+    <%- end -%>
+    remove_column :<%= table_name %>, :<%= attribute.name %>, :<%= attribute.type %><%= attribute.inject_options %>
+  <%- end -%>
+<%- end -%>
+<%- end -%>
+  end
+<%- end -%>
+end
diff --git a/activerecord/lib/rails/generators/active_record/model/model_generator.rb b/activerecord/lib/rails/generators/active_record/model/model_generator.rb
new file mode 100644
index 0000000000..7e8d68ce69
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/model/model_generator.rb
@@ -0,0 +1,52 @@
+require 'rails/generators/active_record'
+
+module ActiveRecord
+  module Generators # :nodoc:
+    class ModelGenerator < Base # :nodoc:
+      argument :attributes, :type => :array, :default => [], :banner => "field[:type][:index] field[:type][:index]"
+
+      check_class_collision
+
+      class_option :migration,  :type => :boolean
+      class_option :timestamps, :type => :boolean
+      class_option :parent,     :type => :string, :desc => "The parent class for the generated model"
+      class_option :indexes,    :type => :boolean, :default => true, :desc => "Add indexes for references and belongs_to columns"
+
+      
+      # creates the migration file for the model.
+
+      def create_migration_file
+        return unless options[:migration] && options[:parent].nil?
+        attributes.each { |a| a.attr_options.delete(:index) if a.reference? && !a.has_index? } if options[:indexes] == false
+        migration_template "../../migration/templates/create_table_migration.rb", "db/migrate/create_#{table_name}.rb"
+      end
+
+      def create_model_file
+        template 'model.rb', File.join('app/models', class_path, "#{file_name}.rb")
+      end
+
+      def create_module_file
+        return if regular_class_path.empty?
+        template 'module.rb', File.join('app/models', "#{class_path.join('/')}.rb") if behavior == :invoke
+      end
+
+      def attributes_with_index
+        attributes.select { |a| !a.reference? && a.has_index? }
+      end
+
+      def accessible_attributes
+        attributes.reject(&:reference?)
+      end
+
+      hook_for :test_framework
+
+      protected
+
+        # Used by the migration template to determine the parent name of the model
+        def parent_class_name
+          options[:parent] || "ActiveRecord::Base"
+        end
+
+    end
+  end
+end
diff --git a/activerecord/lib/rails/generators/active_record/model/templates/model.rb b/activerecord/lib/rails/generators/active_record/model/templates/model.rb
new file mode 100644
index 0000000000..808598699b
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/model/templates/model.rb
@@ -0,0 +1,10 @@
+<% module_namespacing do -%>
+class <%= class_name %> < <%= parent_class_name.classify %>
+<% attributes.select(&:reference?).each do |attribute| -%>
+  belongs_to :<%= attribute.name %><%= ', polymorphic: true' if attribute.polymorphic? %>
+<% end -%>
+<% if attributes.any?(&:password_digest?) -%>
+  has_secure_password
+<% end -%>
+end
+<% end -%>
diff --git a/activerecord/lib/rails/generators/active_record/model/templates/module.rb b/activerecord/lib/rails/generators/active_record/model/templates/module.rb
new file mode 100644
index 0000000000..a3bf1c37b6
--- /dev/null
+++ b/activerecord/lib/rails/generators/active_record/model/templates/module.rb
@@ -0,0 +1,7 @@
+<% module_namespacing do -%>
+module <%= class_path.map(&:camelize).join('::') %>
+  def self.table_name_prefix
+    '<%= namespaced? ? namespaced_class_path.join('_') : class_path.join('_') %>_'
+  end
+end
+<% end -%>
diff --git a/activerecord/test/.gitignore b/activerecord/test/.gitignore
new file mode 100644
index 0000000000..a0ec5967dd
--- /dev/null
+++ b/activerecord/test/.gitignore
@@ -0,0 +1 @@
+/config.yml
diff --git a/activerecord/test/active_record/connection_adapters/fake_adapter.rb b/activerecord/test/active_record/connection_adapters/fake_adapter.rb
new file mode 100644
index 0000000000..64cde143a1
--- /dev/null
+++ b/activerecord/test/active_record/connection_adapters/fake_adapter.rb
@@ -0,0 +1,46 @@
+module ActiveRecord
+  module ConnectionHandling
+    def fake_connection(config)
+      ConnectionAdapters::FakeAdapter.new nil, logger
+    end
+  end
+
+  module ConnectionAdapters
+    class FakeAdapter < AbstractAdapter
+      attr_accessor :tables, :primary_keys
+
+      @columns = Hash.new { |h,k| h[k] = [] }
+      class << self
+        attr_reader :columns
+      end
+
+      def initialize(connection, logger)
+        super
+        @tables       = []
+        @primary_keys = {}
+        @columns      = self.class.columns
+      end
+
+      def primary_key(table)
+        @primary_keys[table]
+      end
+
+      def merge_column(table_name, name, sql_type = nil, options = {})
+        @columns[table_name] << ActiveRecord::ConnectionAdapters::Column.new(
+          name.to_s,
+          options[:default],
+          lookup_cast_type(sql_type.to_s),
+          sql_type.to_s,
+          options[:null])
+      end
+
+      def columns(table_name)
+        @columns[table_name]
+      end
+
+      def active?
+        true
+      end
+    end
+  end
+end
diff --git a/activerecord/test/assets/example.log b/activerecord/test/assets/example.log
new file mode 100644
index 0000000000..f084369d8c
--- /dev/null
+++ b/activerecord/test/assets/example.log
@@ -0,0 +1 @@
+# Logfile created on Wed Oct 31 16:05:13 +0000 2007 by logger.rb/1.5.2.9
diff --git a/activerecord/test/assets/flowers.jpg b/activerecord/test/assets/flowers.jpg
new file mode 100644
index 0000000000..fe9df546df
--- /dev/null
+++ b/activerecord/test/assets/flowers.jpg
diff --git a/activerecord/test/assets/test.txt b/activerecord/test/assets/test.txt
new file mode 100644
index 0000000000..6754f0612e
--- /dev/null
+++ b/activerecord/test/assets/test.txt
@@ -0,0 +1 @@
+%00
diff --git a/activerecord/test/cases/adapter_test.rb b/activerecord/test/cases/adapter_test.rb
new file mode 100644
index 0000000000..6f84bae432
--- /dev/null
+++ b/activerecord/test/cases/adapter_test.rb
@@ -0,0 +1,249 @@
+require "cases/helper"
+require "models/book"
+require "models/post"
+require "models/author"
+
+module ActiveRecord
+  class AdapterTest < ActiveRecord::TestCase
+    def setup
+      @connection = ActiveRecord::Base.connection
+    end
+
+    ##
+    # PostgreSQL does not support null bytes in strings
+    unless current_adapter?(:PostgreSQLAdapter)
+      def test_update_prepared_statement
+        b = Book.create(name: "my \x00 book")
+        b.reload
+        assert_equal "my \x00 book", b.name
+        b.update_attributes(name: "my other \x00 book")
+        b.reload
+        assert_equal "my other \x00 book", b.name
+      end
+    end
+
+    def test_tables
+      tables = @connection.tables
+      assert tables.include?("accounts")
+      assert tables.include?("authors")
+      assert tables.include?("tasks")
+      assert tables.include?("topics")
+    end
+
+    def test_table_exists?
+      assert @connection.table_exists?("accounts")
+      assert !@connection.table_exists?("nonexistingtable")
+      assert !@connection.table_exists?(nil)
+    end
+
+    def test_indexes
+      idx_name = "accounts_idx"
+
+      if @connection.respond_to?(:indexes)
+        indexes = @connection.indexes("accounts")
+        assert indexes.empty?
+
+        @connection.add_index :accounts, :firm_id, :name => idx_name
+        indexes = @connection.indexes("accounts")
+        assert_equal "accounts", indexes.first.table
+        assert_equal idx_name, indexes.first.name
+        assert !indexes.first.unique
+        assert_equal ["firm_id"], indexes.first.columns
+      else
+        warn "#{@connection.class} does not respond to #indexes"
+      end
+
+    ensure
+      @connection.remove_index(:accounts, :name => idx_name) rescue nil
+    end
+
+    def test_current_database
+      if @connection.respond_to?(:current_database)
+        assert_equal ARTest.connection_config['arunit']['database'], @connection.current_database
+      end
+    end
+
+    if current_adapter?(:MysqlAdapter)
+      def test_charset
+        assert_not_nil @connection.charset
+        assert_not_equal 'character_set_database', @connection.charset
+        assert_equal @connection.show_variable('character_set_database'), @connection.charset
+      end
+
+      def test_collation
+        assert_not_nil @connection.collation
+        assert_not_equal 'collation_database', @connection.collation
+        assert_equal @connection.show_variable('collation_database'), @connection.collation
+      end
+
+      def test_show_nonexistent_variable_returns_nil
+        assert_nil @connection.show_variable('foo_bar_baz')
+      end
+
+      def test_not_specifying_database_name_for_cross_database_selects
+        begin
+          assert_nothing_raised do
+            ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations['arunit'].except(:database))
+
+            config = ARTest.connection_config
+            ActiveRecord::Base.connection.execute(
+              "SELECT #{config['arunit']['database']}.pirates.*, #{config['arunit2']['database']}.courses.* " \
+              "FROM #{config['arunit']['database']}.pirates, #{config['arunit2']['database']}.courses"
+            )
+          end
+        ensure
+          ActiveRecord::Base.establish_connection :arunit
+        end
+      end
+    end
+
+    def test_table_alias
+      def @connection.test_table_alias_length() 10; end
+      class << @connection
+        alias_method :old_table_alias_length, :table_alias_length
+        alias_method :table_alias_length,     :test_table_alias_length
+      end
+
+      assert_equal 'posts',      @connection.table_alias_for('posts')
+      assert_equal 'posts_comm', @connection.table_alias_for('posts_comments')
+      assert_equal 'dbo_posts',  @connection.table_alias_for('dbo.posts')
+
+      class << @connection
+        remove_method :table_alias_length
+        alias_method :table_alias_length, :old_table_alias_length
+      end
+    end
+
+    # test resetting sequences in odd tables in PostgreSQL
+    if ActiveRecord::Base.connection.respond_to?(:reset_pk_sequence!)
+      require 'models/movie'
+      require 'models/subscriber'
+
+      def test_reset_empty_table_with_custom_pk
+        Movie.delete_all
+        Movie.connection.reset_pk_sequence! 'movies'
+        assert_equal 1, Movie.create(:name => 'fight club').id
+      end
+
+      def test_reset_table_with_non_integer_pk
+        Subscriber.delete_all
+        Subscriber.connection.reset_pk_sequence! 'subscribers'
+        sub = Subscriber.new(:name => 'robert drake')
+        sub.id = 'bob drake'
+        assert_nothing_raised { sub.save! }
+      end
+    end
+
+    def test_uniqueness_violations_are_translated_to_specific_exception
+      @connection.execute "INSERT INTO subscribers(nick) VALUES('me')"
+      assert_raises(ActiveRecord::RecordNotUnique) do
+        @connection.execute "INSERT INTO subscribers(nick) VALUES('me')"
+      end
+    end
+
+    unless current_adapter?(:SQLite3Adapter)
+      def test_foreign_key_violations_are_translated_to_specific_exception
+        assert_raises(ActiveRecord::InvalidForeignKey) do
+          # Oracle adapter uses prefetched primary key values from sequence and passes them to connection adapter insert method
+          if @connection.prefetch_primary_key?
+            id_value = @connection.next_sequence_value(@connection.default_sequence_name("fk_test_has_fk", "id"))
+            @connection.execute "INSERT INTO fk_test_has_fk (id, fk_id) VALUES (#{id_value},0)"
+          else
+            @connection.execute "INSERT INTO fk_test_has_fk (fk_id) VALUES (0)"
+          end
+        end
+      end
+
+      def test_foreign_key_violations_are_translated_to_specific_exception_with_validate_false
+        klass_has_fk = Class.new(ActiveRecord::Base) do
+          self.table_name = 'fk_test_has_fk'
+        end
+
+        assert_raises(ActiveRecord::InvalidForeignKey) do
+          has_fk = klass_has_fk.new
+          has_fk.fk_id = 1231231231
+          has_fk.save(validate: false)
+        end
+      end
+    end
+
+    def test_disable_referential_integrity
+      assert_nothing_raised do
+        @connection.disable_referential_integrity do
+          # Oracle adapter uses prefetched primary key values from sequence and passes them to connection adapter insert method
+          if @connection.prefetch_primary_key?
+            id_value = @connection.next_sequence_value(@connection.default_sequence_name("fk_test_has_fk", "id"))
+            @connection.execute "INSERT INTO fk_test_has_fk (id, fk_id) VALUES (#{id_value},0)"
+          else
+            @connection.execute "INSERT INTO fk_test_has_fk (fk_id) VALUES (0)"
+          end
+          # should delete created record as otherwise disable_referential_integrity will try to enable constraints after executed block
+          # and will fail (at least on Oracle)
+          @connection.execute "DELETE FROM fk_test_has_fk"
+        end
+      end
+    end
+
+    def test_select_all_always_return_activerecord_result
+      result = @connection.select_all "SELECT * FROM posts"
+      assert result.is_a?(ActiveRecord::Result)
+    end
+
+    def test_select_methods_passing_a_association_relation
+      author = Author.create!(name: 'john')
+      Post.create!(author: author, title: 'foo', body: 'bar')
+      query = author.posts.where(title: 'foo').select(:title)
+      assert_equal({"title" => "foo"}, @connection.select_one(query.arel, nil, query.bind_values))
+      assert_equal({"title" => "foo"}, @connection.select_one(query))
+      assert @connection.select_all(query).is_a?(ActiveRecord::Result)
+      assert_equal "foo", @connection.select_value(query)
+      assert_equal ["foo"], @connection.select_values(query)
+    end
+
+    def test_select_methods_passing_a_relation
+      Post.create!(title: 'foo', body: 'bar')
+      query = Post.where(title: 'foo').select(:title)
+      assert_equal({"title" => "foo"}, @connection.select_one(query.arel, nil, query.bind_values))
+      assert_equal({"title" => "foo"}, @connection.select_one(query))
+      assert @connection.select_all(query).is_a?(ActiveRecord::Result)
+      assert_equal "foo", @connection.select_value(query)
+      assert_equal ["foo"], @connection.select_values(query)
+    end
+
+    test "type_to_sql returns a String for unmapped types" do
+      assert_equal "special_db_type", @connection.type_to_sql(:special_db_type)
+    end
+  end
+
+  class AdapterTestWithoutTransaction < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    class Klass < ActiveRecord::Base
+    end
+
+    def setup
+      Klass.establish_connection :arunit
+      @connection = Klass.connection
+    end
+
+    teardown do
+      Klass.remove_connection
+    end
+
+    unless in_memory_db?
+      test "transaction state is reset after a reconnect" do
+        @connection.begin_transaction
+        assert @connection.transaction_open?
+        @connection.reconnect!
+        assert !@connection.transaction_open?
+      end
+
+      test "transaction state is reset after a disconnect" do
+        @connection.begin_transaction
+        assert @connection.transaction_open?
+        @connection.disconnect!
+        assert !@connection.transaction_open?
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/active_schema_test.rb b/activerecord/test/cases/adapters/mysql/active_schema_test.rb
new file mode 100644
index 0000000000..7c0f11b033
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/active_schema_test.rb
@@ -0,0 +1,155 @@
+require "cases/helper"
+require 'support/connection_helper'
+
+class ActiveSchemaTest < ActiveRecord::TestCase
+  include ConnectionHelper
+
+  def setup
+    ActiveRecord::Base.connection.singleton_class.class_eval do
+      alias_method :execute_without_stub, :execute
+      def execute(sql, name = nil) return sql end
+    end
+  end
+
+  teardown do
+    reset_connection
+  end
+
+  def test_add_index
+    # add_index calls table_exists? and index_name_exists? which can't work since execute is stubbed
+    def (ActiveRecord::Base.connection).table_exists?(*); true; end
+    def (ActiveRecord::Base.connection).index_name_exists?(*); false; end
+
+    expected = "CREATE  INDEX `index_people_on_last_name`  ON `people` (`last_name`) "
+    assert_equal expected, add_index(:people, :last_name, :length => nil)
+
+    expected = "CREATE  INDEX `index_people_on_last_name`  ON `people` (`last_name`(10)) "
+    assert_equal expected, add_index(:people, :last_name, :length => 10)
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`(15)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], :length => 15)
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], :length => {:last_name => 15})
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`(10)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], :length => {:last_name => 15, :first_name => 10})
+
+    %w(SPATIAL FULLTEXT UNIQUE).each do |type|
+      expected = "CREATE #{type} INDEX `index_people_on_last_name`  ON `people` (`last_name`) "
+      assert_equal expected, add_index(:people, :last_name, :type => type)
+    end
+
+    %w(btree hash).each do |using|
+      expected = "CREATE  INDEX `index_people_on_last_name` USING #{using} ON `people` (`last_name`) "
+      assert_equal expected, add_index(:people, :last_name, :using => using)
+    end
+
+    expected = "CREATE  INDEX `index_people_on_last_name` USING btree ON `people` (`last_name`(10)) "
+    assert_equal expected, add_index(:people, :last_name, :length => 10, :using => :btree)
+
+    expected = "CREATE  INDEX `index_people_on_last_name` USING btree ON `people` (`last_name`(10)) ALGORITHM = COPY"
+    assert_equal expected, add_index(:people, :last_name, :length => 10, using: :btree, algorithm: :copy)
+
+    assert_raise ArgumentError do
+      add_index(:people, :last_name, algorithm: :coyp)
+    end
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name` USING btree ON `people` (`last_name`(15), `first_name`(15)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], :length => 15, :using => :btree)
+  end
+
+  def test_drop_table
+    assert_equal "DROP TABLE `people`", drop_table(:people)
+  end
+
+  if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+    def test_create_mysql_database_with_encoding
+      assert_equal "CREATE DATABASE `matt` DEFAULT CHARACTER SET `utf8`", create_database(:matt)
+      assert_equal "CREATE DATABASE `aimonetti` DEFAULT CHARACTER SET `latin1`", create_database(:aimonetti, {:charset => 'latin1'})
+      assert_equal "CREATE DATABASE `matt_aimonetti` DEFAULT CHARACTER SET `big5` COLLATE `big5_chinese_ci`", create_database(:matt_aimonetti, {:charset => :big5, :collation => :big5_chinese_ci})
+    end
+
+    def test_recreate_mysql_database_with_encoding
+      create_database(:luca, {:charset => 'latin1'})
+      assert_equal "CREATE DATABASE `luca` DEFAULT CHARACTER SET `latin1`", recreate_database(:luca, {:charset => 'latin1'})
+    end
+  end
+
+  def test_add_column
+    assert_equal "ALTER TABLE `people` ADD `last_name` varchar(255)", add_column(:people, :last_name, :string)
+  end
+
+  def test_add_column_with_limit
+    assert_equal "ALTER TABLE `people` ADD `key` varchar(32)", add_column(:people, :key, :string, :limit => 32)
+  end
+
+  def test_drop_table_with_specific_database
+    assert_equal "DROP TABLE `otherdb`.`people`", drop_table('otherdb.people')
+  end
+
+  def test_add_timestamps
+    with_real_execute do
+      begin
+        ActiveRecord::Base.connection.create_table :delete_me
+        ActiveRecord::Base.connection.add_timestamps :delete_me
+        assert column_present?('delete_me', 'updated_at', 'datetime')
+        assert column_present?('delete_me', 'created_at', 'datetime')
+      ensure
+        ActiveRecord::Base.connection.drop_table :delete_me rescue nil
+      end
+    end
+  end
+
+  def test_remove_timestamps
+    with_real_execute do
+      begin
+        ActiveRecord::Base.connection.create_table :delete_me do |t|
+          t.timestamps
+        end
+        ActiveRecord::Base.connection.remove_timestamps :delete_me
+        assert !column_present?('delete_me', 'updated_at', 'datetime')
+        assert !column_present?('delete_me', 'created_at', 'datetime')
+      ensure
+        ActiveRecord::Base.connection.drop_table :delete_me rescue nil
+      end
+    end
+  end
+
+  def test_indexes_in_create
+    ActiveRecord::Base.connection.stubs(:table_exists?).with(:temp).returns(false)
+    ActiveRecord::Base.connection.stubs(:index_name_exists?).with(:index_temp_on_zip).returns(false)
+
+    expected = "CREATE TEMPORARY TABLE `temp` ( INDEX `index_temp_on_zip`  (`zip`) ) ENGINE=InnoDB AS SELECT id, name, zip FROM a_really_complicated_query"
+    actual = ActiveRecord::Base.connection.create_table(:temp, temporary: true, as: "SELECT id, name, zip FROM a_really_complicated_query") do |t|
+      t.index :zip
+    end
+
+    assert_equal expected, actual
+  end
+
+  private
+    def with_real_execute
+      ActiveRecord::Base.connection.singleton_class.class_eval do
+        alias_method :execute_with_stub, :execute
+        remove_method :execute
+        alias_method :execute, :execute_without_stub
+      end
+
+      yield
+    ensure
+      ActiveRecord::Base.connection.singleton_class.class_eval do
+        remove_method :execute
+        alias_method :execute, :execute_with_stub
+      end
+    end
+
+    def method_missing(method_symbol, *arguments)
+      ActiveRecord::Base.connection.send(method_symbol, *arguments)
+    end
+
+    def column_present?(table_name, column_name, type)
+      results = ActiveRecord::Base.connection.select_all("SHOW FIELDS FROM #{table_name} LIKE '#{column_name}'")
+      results.first && results.first['Type'] == type
+    end
+end
diff --git a/activerecord/test/cases/adapters/mysql/case_sensitivity_test.rb b/activerecord/test/cases/adapters/mysql/case_sensitivity_test.rb
new file mode 100644
index 0000000000..340fc95503
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/case_sensitivity_test.rb
@@ -0,0 +1,55 @@
+require "cases/helper"
+require 'models/person'
+
+class MysqlCaseSensitivityTest < ActiveRecord::TestCase
+  class CollationTest < ActiveRecord::Base
+  end
+
+  repair_validations(CollationTest)
+
+  def test_columns_include_collation_different_from_table
+    assert_equal 'utf8_bin', CollationTest.columns_hash['string_cs_column'].collation
+    assert_equal 'utf8_general_ci', CollationTest.columns_hash['string_ci_column'].collation
+  end
+
+  def test_case_sensitive
+    assert !CollationTest.columns_hash['string_ci_column'].case_sensitive?
+    assert CollationTest.columns_hash['string_cs_column'].case_sensitive?
+  end
+
+  def test_case_insensitive_comparison_for_ci_column
+    CollationTest.validates_uniqueness_of(:string_ci_column, :case_sensitive => false)
+    CollationTest.create!(:string_ci_column => 'A')
+    invalid = CollationTest.new(:string_ci_column => 'a')
+    queries = assert_sql { invalid.save }
+    ci_uniqueness_query = queries.detect { |q| q.match(/string_ci_column/) }
+    assert_no_match(/lower/i, ci_uniqueness_query)
+  end
+
+  def test_case_insensitive_comparison_for_cs_column
+    CollationTest.validates_uniqueness_of(:string_cs_column, :case_sensitive => false)
+    CollationTest.create!(:string_cs_column => 'A')
+    invalid = CollationTest.new(:string_cs_column => 'a')
+    queries = assert_sql { invalid.save }
+    cs_uniqueness_query = queries.detect { |q| q.match(/string_cs_column/) }
+    assert_match(/lower/i, cs_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_ci_column
+    CollationTest.validates_uniqueness_of(:string_ci_column, :case_sensitive => true)
+    CollationTest.create!(:string_ci_column => 'A')
+    invalid = CollationTest.new(:string_ci_column => 'A')
+    queries = assert_sql { invalid.save }
+    ci_uniqueness_query = queries.detect { |q| q.match(/string_ci_column/) }
+    assert_match(/binary/i, ci_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_cs_column
+    CollationTest.validates_uniqueness_of(:string_cs_column, :case_sensitive => true)
+    CollationTest.create!(:string_cs_column => 'A')
+    invalid = CollationTest.new(:string_cs_column => 'A')
+    queries = assert_sql { invalid.save }
+    cs_uniqueness_query = queries.detect { |q| q.match(/string_cs_column/) }
+    assert_no_match(/binary/i, cs_uniqueness_query)
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/connection_test.rb b/activerecord/test/cases/adapters/mysql/connection_test.rb
new file mode 100644
index 0000000000..b0759dffde
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/connection_test.rb
@@ -0,0 +1,179 @@
+require "cases/helper"
+require 'support/connection_helper'
+require 'support/ddl_helper'
+
+class MysqlConnectionTest < ActiveRecord::TestCase
+  include ConnectionHelper
+  include DdlHelper
+
+  class Klass < ActiveRecord::Base
+  end
+
+  def setup
+    super
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def test_mysql_reconnect_attribute_after_connection_with_reconnect_true
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge({:reconnect => true}))
+      assert ActiveRecord::Base.connection.raw_connection.reconnect
+    end
+  end
+
+  unless ARTest.connection_config['arunit']['socket']
+    def test_connect_with_url
+      run_without_connection do
+        ar_config = ARTest.connection_config['arunit']
+
+        url = "mysql://#{ar_config["username"]}@localhost/#{ar_config["database"]}"
+        Klass.establish_connection(url)
+        assert_equal ar_config['database'], Klass.connection.current_database
+      end
+    end
+  end
+
+  def test_mysql_reconnect_attribute_after_connection_with_reconnect_false
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge({:reconnect => false}))
+      assert !ActiveRecord::Base.connection.raw_connection.reconnect
+    end
+  end
+
+  def test_no_automatic_reconnection_after_timeout
+    assert @connection.active?
+    @connection.update('set @@wait_timeout=1')
+    sleep 2
+    assert !@connection.active?
+
+    # Repair all fixture connections so other tests won't break.
+    @fixture_connections.each do |c|
+      c.verify!
+    end
+  end
+
+  def test_successful_reconnection_after_timeout_with_manual_reconnect
+    assert @connection.active?
+    @connection.update('set @@wait_timeout=1')
+    sleep 2
+    @connection.reconnect!
+    assert @connection.active?
+  end
+
+  def test_successful_reconnection_after_timeout_with_verify
+    assert @connection.active?
+    @connection.update('set @@wait_timeout=1')
+    sleep 2
+    @connection.verify!
+    assert @connection.active?
+  end
+
+  def test_bind_value_substitute
+    bind_param = @connection.substitute_at('foo', 0)
+    assert_equal Arel.sql('?'), bind_param
+  end
+
+  def test_exec_no_binds
+    with_example_table do
+      result = @connection.exec_query('SELECT id, data FROM ex')
+      assert_equal 0, result.rows.length
+      assert_equal 2, result.columns.length
+      assert_equal %w{ id data }, result.columns
+
+      @connection.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+
+      # if there are no bind parameters, it will return a string (due to
+      # the libmysql api)
+      result = @connection.exec_query('SELECT id, data FROM ex')
+      assert_equal 1, result.rows.length
+      assert_equal 2, result.columns.length
+
+      assert_equal [['1', 'foo']], result.rows
+    end
+  end
+
+  def test_exec_with_binds
+    with_example_table do
+      @connection.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+      result = @connection.exec_query(
+        'SELECT id, data FROM ex WHERE id = ?', nil, [[nil, 1]])
+
+      assert_equal 1, result.rows.length
+      assert_equal 2, result.columns.length
+
+      assert_equal [[1, 'foo']], result.rows
+    end
+  end
+
+  def test_exec_typecasts_bind_vals
+    with_example_table do
+      @connection.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+      column = @connection.columns('ex').find { |col| col.name == 'id' }
+
+      result = @connection.exec_query(
+        'SELECT id, data FROM ex WHERE id = ?', nil, [[column, '1-fuu']])
+
+      assert_equal 1, result.rows.length
+      assert_equal 2, result.columns.length
+
+      assert_equal [[1, 'foo']], result.rows
+    end
+  end
+
+  # Test that MySQL allows multiple results for stored procedures
+  if defined?(Mysql) && Mysql.const_defined?(:CLIENT_MULTI_RESULTS)
+    def test_multi_results
+      rows = ActiveRecord::Base.connection.select_rows('CALL ten();')
+      assert_equal 10, rows[0][0].to_i, "ten() did not return 10 as expected: #{rows.inspect}"
+      assert @connection.active?, "Bad connection use by 'MysqlAdapter.select_rows'"
+    end
+  end
+
+  def test_mysql_default_in_strict_mode
+    result = @connection.exec_query "SELECT @@SESSION.sql_mode"
+    assert_equal [["STRICT_ALL_TABLES"]], result.rows
+  end
+
+  def test_mysql_strict_mode_disabled
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge({:strict => false}))
+      result = ActiveRecord::Base.connection.exec_query "SELECT @@SESSION.sql_mode"
+      assert_equal [['']], result.rows
+    end
+  end
+
+  def test_mysql_set_session_variable
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:default_week_format => 3}}))
+      session_mode = ActiveRecord::Base.connection.exec_query "SELECT @@SESSION.DEFAULT_WEEK_FORMAT"
+      assert_equal 3, session_mode.rows.first.first.to_i
+    end
+  end
+
+  def test_mysql_sql_mode_variable_overides_strict_mode
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { 'sql_mode' => 'ansi' }))
+      result = ActiveRecord::Base.connection.exec_query 'SELECT @@SESSION.sql_mode'
+      assert_not_equal [['STRICT_ALL_TABLES']], result.rows
+    end
+  end
+
+  def test_mysql_set_session_variable_to_default
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:default_week_format => :default}}))
+      global_mode = ActiveRecord::Base.connection.exec_query "SELECT @@GLOBAL.DEFAULT_WEEK_FORMAT"
+      session_mode = ActiveRecord::Base.connection.exec_query "SELECT @@SESSION.DEFAULT_WEEK_FORMAT"
+      assert_equal global_mode.rows, session_mode.rows
+    end
+  end
+
+  private
+
+  def with_example_table(&block)
+    definition ||= <<-SQL
+      `id` int(11) auto_increment PRIMARY KEY,
+      `data` varchar(255)
+    SQL
+    super(@connection, 'ex', definition, &block)
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/consistency_test.rb b/activerecord/test/cases/adapters/mysql/consistency_test.rb
new file mode 100644
index 0000000000..083d533bb2
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/consistency_test.rb
@@ -0,0 +1,48 @@
+require "cases/helper"
+
+class MysqlConsistencyTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  class Consistency < ActiveRecord::Base
+    self.table_name = "mysql_consistency"
+  end
+
+  setup do
+    @old_emulate_booleans = ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans
+    ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans = false
+
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("mysql_consistency") do |t|
+      t.boolean "a_bool"
+      t.string "a_string"
+    end
+    Consistency.reset_column_information
+    Consistency.create!
+  end
+
+  teardown do
+    ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans = @old_emulate_booleans
+    @connection.drop_table "mysql_consistency"
+  end
+
+  test "boolean columns with random value type cast to 0 when emulate_booleans is false" do
+    with_new = Consistency.new
+    with_last = Consistency.last
+    with_new.a_bool = 'wibble'
+    with_last.a_bool = 'wibble'
+
+    assert_equal 0, with_new.a_bool
+    assert_equal 0, with_last.a_bool
+  end
+
+  test "string columns call #to_s" do
+    with_new = Consistency.new
+    with_last = Consistency.last
+    thing = Object.new
+    with_new.a_string = thing
+    with_last.a_string = thing
+
+    assert_equal thing.to_s, with_new.a_string
+    assert_equal thing.to_s, with_last.a_string
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/enum_test.rb b/activerecord/test/cases/adapters/mysql/enum_test.rb
new file mode 100644
index 0000000000..f4e7a3ef0a
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/enum_test.rb
@@ -0,0 +1,10 @@
+require "cases/helper"
+
+class MysqlEnumTest < ActiveRecord::TestCase
+  class EnumTest < ActiveRecord::Base
+  end
+
+  def test_enum_limit
+    assert_equal 6, EnumTest.columns.first.limit
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/mysql_adapter_test.rb b/activerecord/test/cases/adapters/mysql/mysql_adapter_test.rb
new file mode 100644
index 0000000000..28106d3772
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/mysql_adapter_test.rb
@@ -0,0 +1,147 @@
+# encoding: utf-8
+
+require "cases/helper"
+require 'support/ddl_helper'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class MysqlAdapterTest < ActiveRecord::TestCase
+      include DdlHelper
+
+      def setup
+        @conn = ActiveRecord::Base.connection
+      end
+
+      def test_bad_connection_mysql
+        assert_raise ActiveRecord::NoDatabaseError do
+          configuration = ActiveRecord::Base.configurations['arunit'].merge(database: 'inexistent_activerecord_unittest')
+          connection = ActiveRecord::Base.mysql_connection(configuration)
+          connection.exec_query('drop table if exists ex')
+        end
+      end
+
+      def test_valid_column
+        with_example_table do
+          column = @conn.columns('ex').find { |col| col.name == 'id' }
+          assert @conn.valid_type?(column.type)
+        end
+      end
+
+      def test_invalid_column
+        assert_not @conn.valid_type?(:foobar)
+      end
+
+      def test_client_encoding
+        assert_equal Encoding::UTF_8, @conn.client_encoding
+      end
+
+      def test_exec_insert_number
+        with_example_table do
+          insert(@conn, 'number' => 10)
+
+          result = @conn.exec_query('SELECT number FROM ex WHERE number = 10')
+
+          assert_equal 1, result.rows.length
+          # if there are no bind parameters, it will return a string (due to
+          # the libmysql api)
+          assert_equal '10', result.rows.last.last
+        end
+      end
+
+      def test_exec_insert_string
+        with_example_table do
+          str = 'いただきます！'
+          insert(@conn, 'number' => 10, 'data' => str)
+
+          result = @conn.exec_query('SELECT number, data FROM ex WHERE number = 10')
+
+          value = result.rows.last.last
+
+          # FIXME: this should probably be inside the mysql AR adapter?
+          value.force_encoding(@conn.client_encoding)
+
+          # The strings in this file are utf-8, so transcode to utf-8
+          value.encode!(Encoding::UTF_8)
+
+          assert_equal str, value
+        end
+      end
+
+      def test_tables_quoting
+        @conn.tables(nil, "foo-bar", nil)
+        flunk
+      rescue => e
+        # assertion for *quoted* database properly
+        assert_match(/database 'foo-bar'/, e.inspect)
+      end
+
+      def test_pk_and_sequence_for
+        with_example_table do
+          pk, seq = @conn.pk_and_sequence_for('ex')
+          assert_equal 'id', pk
+          assert_equal @conn.default_sequence_name('ex', 'id'), seq
+        end
+      end
+
+      def test_pk_and_sequence_for_with_non_standard_primary_key
+        with_example_table '`code` INT(11) auto_increment, PRIMARY KEY (`code`)' do
+          pk, seq = @conn.pk_and_sequence_for('ex')
+          assert_equal 'code', pk
+          assert_equal @conn.default_sequence_name('ex', 'code'), seq
+        end
+      end
+
+      def test_pk_and_sequence_for_with_custom_index_type_pk
+        with_example_table '`id` INT(11) auto_increment, PRIMARY KEY USING BTREE (`id`)' do
+          pk, seq = @conn.pk_and_sequence_for('ex')
+          assert_equal 'id', pk
+          assert_equal @conn.default_sequence_name('ex', 'id'), seq
+        end
+      end
+
+      def test_tinyint_integer_typecasting
+        with_example_table '`status` TINYINT(4)' do
+          insert(@conn, { 'status' => 2 }, 'ex')
+
+          result = @conn.exec_query('SELECT status FROM ex')
+
+          assert_equal 2, result.column_types['status'].type_cast_from_database(result.last['status'])
+        end
+      end
+
+      def test_supports_extensions
+        assert_not @conn.supports_extensions?, 'does not support extensions'
+      end
+
+      def test_respond_to_enable_extension
+        assert @conn.respond_to?(:enable_extension)
+      end
+
+      def test_respond_to_disable_extension
+        assert @conn.respond_to?(:disable_extension)
+      end
+
+      private
+      def insert(ctx, data, table='ex')
+        binds   = data.map { |name, value|
+          [ctx.columns(table).find { |x| x.name == name }, value]
+        }
+        columns = binds.map(&:first).map(&:name)
+
+        sql = "INSERT INTO #{table} (#{columns.join(", ")})
+               VALUES (#{(['?'] * columns.length).join(', ')})"
+
+        ctx.exec_insert(sql, 'SQL', binds)
+      end
+
+      def with_example_table(definition = nil, &block)
+        definition ||= <<-SQL
+          `id` int(11) auto_increment PRIMARY KEY,
+          `number` integer,
+          `data` varchar(255)
+        SQL
+        super(@conn, 'ex', definition, &block)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/quoting_test.rb b/activerecord/test/cases/adapters/mysql/quoting_test.rb
new file mode 100644
index 0000000000..d8a954efa8
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/quoting_test.rb
@@ -0,0 +1,25 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class MysqlAdapter
+      class QuotingTest < ActiveRecord::TestCase
+        def setup
+          @conn = ActiveRecord::Base.connection
+        end
+
+        def test_type_cast_true
+          c = Column.new(nil, 1, Type::Boolean.new)
+          assert_equal 1, @conn.type_cast(true, nil)
+          assert_equal 1, @conn.type_cast(true, c)
+        end
+
+        def test_type_cast_false
+          c = Column.new(nil, 1, Type::Boolean.new)
+          assert_equal 0, @conn.type_cast(false, nil)
+          assert_equal 0, @conn.type_cast(false, c)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/reserved_word_test.rb b/activerecord/test/cases/adapters/mysql/reserved_word_test.rb
new file mode 100644
index 0000000000..61ae0abfd1
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/reserved_word_test.rb
@@ -0,0 +1,153 @@
+require "cases/helper"
+
+class Group < ActiveRecord::Base
+  Group.table_name = 'group'
+  belongs_to :select
+  has_one :values
+end
+
+class Select < ActiveRecord::Base
+  Select.table_name = 'select'
+  has_many :groups
+end
+
+class Values < ActiveRecord::Base
+  Values.table_name = 'values'
+end
+
+class Distinct < ActiveRecord::Base
+  Distinct.table_name = 'distinct'
+  has_and_belongs_to_many :selects
+  has_many :values, :through => :groups
+end
+
+# a suite of tests to ensure the ConnectionAdapters#MysqlAdapter can handle tables with
+# reserved word names (ie: group, order, values, etc...)
+class MysqlReservedWordTest < ActiveRecord::TestCase
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    # we call execute directly here (and do similar below) because ActiveRecord::Base#create_table()
+    # will fail with these table names if these test cases fail
+
+    create_tables_directly 'group'=>'id int auto_increment primary key, `order` varchar(255), select_id int',
+      'select'=>'id int auto_increment primary key',
+      'values'=>'id int auto_increment primary key, group_id int',
+      'distinct'=>'id int auto_increment primary key',
+      'distinct_select'=>'distinct_id int, select_id int'
+  end
+
+  teardown do
+    drop_tables_directly ['group', 'select', 'values', 'distinct', 'distinct_select', 'order']
+  end
+
+  # create tables with reserved-word names and columns
+  def test_create_tables
+    assert_nothing_raised {
+      @connection.create_table :order do |t|
+        t.column :group, :string
+      end
+    }
+  end
+
+  # rename tables with reserved-word names
+  def test_rename_tables
+    assert_nothing_raised { @connection.rename_table(:group, :order) }
+  end
+
+  # alter column with a reserved-word name in a table with a reserved-word name
+  def test_change_columns
+    assert_nothing_raised { @connection.change_column_default(:group, :order, 'whatever') }
+    #the quoting here will reveal any double quoting issues in change_column's interaction with the column method in the adapter
+    assert_nothing_raised { @connection.change_column('group', 'order', :Int, :default => 0) }
+    assert_nothing_raised { @connection.rename_column(:group, :order, :values) }
+  end
+
+  # introspect table with reserved word name
+  def test_introspect
+    assert_nothing_raised { @connection.columns(:group) }
+    assert_nothing_raised { @connection.indexes(:group) }
+  end
+
+  #fixtures
+  self.use_instantiated_fixtures = true
+  self.use_transactional_fixtures = false
+
+  #activerecord model class with reserved-word table name
+  def test_activerecord_model
+    create_test_fixtures :select, :distinct, :group, :values, :distinct_select
+    x = nil
+    assert_nothing_raised { x = Group.new }
+    x.order = 'x'
+    assert_nothing_raised { x.save }
+    x.order = 'y'
+    assert_nothing_raised { x.save }
+    assert_nothing_raised { Group.find_by_order('y') }
+    assert_nothing_raised { Group.find(1) }
+    Group.find(1)
+  end
+
+  # has_one association with reserved-word table name
+  def test_has_one_associations
+    create_test_fixtures :select, :distinct, :group, :values, :distinct_select
+    v = nil
+    assert_nothing_raised { v = Group.find(1).values }
+    assert_equal 2, v.id
+  end
+
+  # belongs_to association with reserved-word table name
+  def test_belongs_to_associations
+    create_test_fixtures :select, :distinct, :group, :values, :distinct_select
+    gs = nil
+    assert_nothing_raised { gs = Select.find(2).groups }
+    assert_equal gs.length, 2
+    assert(gs.collect{|x| x.id}.sort == [2, 3])
+  end
+
+  # has_and_belongs_to_many with reserved-word table name
+  def test_has_and_belongs_to_many
+    create_test_fixtures :select, :distinct, :group, :values, :distinct_select
+    s = nil
+    assert_nothing_raised { s = Distinct.find(1).selects }
+    assert_equal s.length, 2
+    assert(s.collect{|x|x.id}.sort == [1, 2])
+  end
+
+  # activerecord model introspection with reserved-word table and column names
+  def test_activerecord_introspection
+    assert_nothing_raised { Group.table_exists? }
+    assert_nothing_raised { Group.columns }
+  end
+
+  # Calculations
+  def test_calculations_work_with_reserved_words
+    assert_nothing_raised { Group.count }
+  end
+
+  def test_associations_work_with_reserved_words
+    assert_nothing_raised { Select.all.merge!(:includes => [:groups]).to_a }
+  end
+
+  #the following functions were added to DRY test cases
+
+  private
+  # custom fixture loader, uses FixtureSet#create_fixtures and appends base_path to the current file's path
+  def create_test_fixtures(*fixture_names)
+    ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT + "/reserved_words", fixture_names)
+  end
+
+  # custom drop table, uses execute on connection to drop a table if it exists. note: escapes table_name
+  def drop_tables_directly(table_names, connection = @connection)
+    table_names.each do |name|
+      connection.execute("DROP TABLE IF EXISTS `#{name}`")
+    end
+  end
+
+  # custom create table, uses execute on connection to create a table, note: escapes table_name, does NOT escape columns
+  def create_tables_directly (tables, connection = @connection)
+    tables.each do |table_name, column_properties|
+      connection.execute("CREATE TABLE `#{table_name}` ( #{column_properties} )")
+    end
+  end
+
+end
diff --git a/activerecord/test/cases/adapters/mysql/schema_test.rb b/activerecord/test/cases/adapters/mysql/schema_test.rb
new file mode 100644
index 0000000000..87c5277e64
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/schema_test.rb
@@ -0,0 +1,100 @@
+require "cases/helper"
+require 'models/post'
+require 'models/comment'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class MysqlSchemaTest < ActiveRecord::TestCase
+      fixtures :posts
+
+      def setup
+        @connection = ActiveRecord::Base.connection
+        db          = Post.connection_pool.spec.config[:database]
+        table       = Post.table_name
+        @db_name    = db
+
+        @omgpost = Class.new(ActiveRecord::Base) do
+          self.table_name = "#{db}.#{table}"
+          def self.name; 'Post'; end
+        end
+
+        @connection.create_table "mysql_doubles"
+      end
+
+      teardown do
+        @connection.execute "drop table if exists mysql_doubles"
+      end
+
+      class MysqlDouble < ActiveRecord::Base
+        self.table_name = "mysql_doubles"
+      end
+
+      def test_float_limits
+        @connection.add_column :mysql_doubles, :float_no_limit, :float
+        @connection.add_column :mysql_doubles, :float_short, :float, limit: 5
+        @connection.add_column :mysql_doubles, :float_long, :float, limit: 53
+
+        @connection.add_column :mysql_doubles, :float_23, :float, limit: 23
+        @connection.add_column :mysql_doubles, :float_24, :float, limit: 24
+        @connection.add_column :mysql_doubles, :float_25, :float, limit: 25
+        MysqlDouble.reset_column_information
+
+        column_no_limit = MysqlDouble.columns.find { |c| c.name == 'float_no_limit' }
+        column_short = MysqlDouble.columns.find { |c| c.name == 'float_short' }
+        column_long = MysqlDouble.columns.find { |c| c.name == 'float_long' }
+
+        column_23 = MysqlDouble.columns.find { |c| c.name == 'float_23' }
+        column_24 = MysqlDouble.columns.find { |c| c.name == 'float_24' }
+        column_25 = MysqlDouble.columns.find { |c| c.name == 'float_25' }
+
+        # Mysql floats are precision 0..24, Mysql doubles are precision 25..53
+        assert_equal 24, column_no_limit.limit
+        assert_equal 24, column_short.limit
+        assert_equal 53, column_long.limit
+
+        assert_equal 24, column_23.limit
+        assert_equal 24, column_24.limit
+        assert_equal 53, column_25.limit
+      end
+
+      def test_schema
+        assert @omgpost.first
+      end
+
+      def test_primary_key
+        assert_equal 'id', @omgpost.primary_key
+      end
+
+      def test_table_exists?
+        name = @omgpost.table_name
+        assert @connection.table_exists?(name), "#{name} table should exist"
+      end
+
+      def test_table_exists_wrong_schema
+        assert(!@connection.table_exists?("#{@db_name}.zomg"), "table should not exist")
+      end
+
+      def test_dump_indexes
+        index_a_name = 'index_key_tests_on_snack'
+        index_b_name = 'index_key_tests_on_pizza'
+        index_c_name = 'index_key_tests_on_awesome'
+
+        table = 'key_tests'
+
+        indexes = @connection.indexes(table).sort_by {|i| i.name}
+        assert_equal 3,indexes.size
+
+        index_a = indexes.select{|i| i.name == index_a_name}[0]
+        index_b = indexes.select{|i| i.name == index_b_name}[0]
+        index_c = indexes.select{|i| i.name == index_c_name}[0]
+        assert_equal :btree, index_a.using
+        assert_nil index_a.type
+        assert_equal :btree, index_b.using
+        assert_nil index_b.type
+
+        assert_nil index_c.using
+        assert_equal :fulltext, index_c.type
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/sp_test.rb b/activerecord/test/cases/adapters/mysql/sp_test.rb
new file mode 100644
index 0000000000..3ca2917ca4
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/sp_test.rb
@@ -0,0 +1,15 @@
+require "cases/helper"
+require 'models/topic'
+
+class StoredProcedureTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  # Test that MySQL allows multiple results for stored procedures
+  if Mysql.const_defined?(:CLIENT_MULTI_RESULTS)
+    def test_multi_results_from_find_by_sql
+      topics = Topic.find_by_sql 'CALL topics();'
+      assert_equal 1, topics.size
+      assert ActiveRecord::Base.connection.active?, "Bad connection use by 'MysqlAdapter.select'"
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/sql_types_test.rb b/activerecord/test/cases/adapters/mysql/sql_types_test.rb
new file mode 100644
index 0000000000..1ddb1b91c9
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/sql_types_test.rb
@@ -0,0 +1,14 @@
+require "cases/helper"
+
+class SqlTypesTest < ActiveRecord::TestCase
+  def test_binary_types
+    assert_equal 'varbinary(64)', type_to_sql(:binary, 64)
+    assert_equal 'varbinary(4095)', type_to_sql(:binary, 4095)
+    assert_equal 'blob(4096)', type_to_sql(:binary, 4096)
+    assert_equal 'blob', type_to_sql(:binary)
+  end
+
+  def type_to_sql(*args)
+    ActiveRecord::Base.connection.type_to_sql(*args)
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql/statement_pool_test.rb b/activerecord/test/cases/adapters/mysql/statement_pool_test.rb
new file mode 100644
index 0000000000..209a0cf464
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/statement_pool_test.rb
@@ -0,0 +1,23 @@
+require 'cases/helper'
+
+module ActiveRecord::ConnectionAdapters
+  class MysqlAdapter
+    class StatementPoolTest < ActiveRecord::TestCase
+      if Process.respond_to?(:fork)
+        def test_cache_is_per_pid
+          cache = StatementPool.new nil, 10
+          cache['foo'] = 'bar'
+          assert_equal 'bar', cache['foo']
+
+          pid = fork {
+            lookup = cache['foo'];
+            exit!(!lookup)
+          }
+
+          Process.waitpid pid
+          assert $?.success?, 'process should exit successfully'
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/active_schema_test.rb b/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
new file mode 100644
index 0000000000..cefc3e3c7e
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
@@ -0,0 +1,155 @@
+require "cases/helper"
+require 'support/connection_helper'
+
+class ActiveSchemaTest < ActiveRecord::TestCase
+  include ConnectionHelper
+
+  def setup
+    ActiveRecord::Base.connection.singleton_class.class_eval do
+      alias_method :execute_without_stub, :execute
+      def execute(sql, name = nil) return sql end
+    end
+  end
+
+  teardown do
+    reset_connection
+  end
+
+  def test_add_index
+    # add_index calls table_exists? and index_name_exists? which can't work since execute is stubbed
+    def (ActiveRecord::Base.connection).table_exists?(*); true; end
+    def (ActiveRecord::Base.connection).index_name_exists?(*); false; end
+
+    expected = "CREATE  INDEX `index_people_on_last_name`  ON `people` (`last_name`) "
+    assert_equal expected, add_index(:people, :last_name, :length => nil)
+
+    expected = "CREATE  INDEX `index_people_on_last_name`  ON `people` (`last_name`(10)) "
+    assert_equal expected, add_index(:people, :last_name, :length => 10)
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`(15)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], :length => 15)
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], :length => {:last_name => 15})
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name`  ON `people` (`last_name`(15), `first_name`(10)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], :length => {:last_name => 15, :first_name => 10})
+
+    %w(SPATIAL FULLTEXT UNIQUE).each do |type|
+      expected = "CREATE #{type} INDEX `index_people_on_last_name`  ON `people` (`last_name`) "
+      assert_equal expected, add_index(:people, :last_name, :type => type)
+    end
+
+    %w(btree hash).each do |using|
+      expected = "CREATE  INDEX `index_people_on_last_name` USING #{using} ON `people` (`last_name`) "
+      assert_equal expected, add_index(:people, :last_name, :using => using)
+    end
+
+    expected = "CREATE  INDEX `index_people_on_last_name` USING btree ON `people` (`last_name`(10)) "
+    assert_equal expected, add_index(:people, :last_name, :length => 10, :using => :btree)
+
+    expected = "CREATE  INDEX `index_people_on_last_name` USING btree ON `people` (`last_name`(10)) ALGORITHM = COPY"
+    assert_equal expected, add_index(:people, :last_name, :length => 10, using: :btree, algorithm: :copy)
+
+    assert_raise ArgumentError do
+      add_index(:people, :last_name, algorithm: :coyp)
+    end
+
+    expected = "CREATE  INDEX `index_people_on_last_name_and_first_name` USING btree ON `people` (`last_name`(15), `first_name`(15)) "
+    assert_equal expected, add_index(:people, [:last_name, :first_name], :length => 15, :using => :btree)
+  end
+
+  def test_drop_table
+    assert_equal "DROP TABLE `people`", drop_table(:people)
+  end
+
+  if current_adapter?(:Mysql2Adapter)
+    def test_create_mysql_database_with_encoding
+      assert_equal "CREATE DATABASE `matt` DEFAULT CHARACTER SET `utf8`", create_database(:matt)
+      assert_equal "CREATE DATABASE `aimonetti` DEFAULT CHARACTER SET `latin1`", create_database(:aimonetti, {:charset => 'latin1'})
+      assert_equal "CREATE DATABASE `matt_aimonetti` DEFAULT CHARACTER SET `big5` COLLATE `big5_chinese_ci`", create_database(:matt_aimonetti, {:charset => :big5, :collation => :big5_chinese_ci})
+    end
+
+    def test_recreate_mysql_database_with_encoding
+      create_database(:luca, {:charset => 'latin1'})
+      assert_equal "CREATE DATABASE `luca` DEFAULT CHARACTER SET `latin1`", recreate_database(:luca, {:charset => 'latin1'})
+    end
+  end
+
+  def test_add_column
+    assert_equal "ALTER TABLE `people` ADD `last_name` varchar(255)", add_column(:people, :last_name, :string)
+  end
+
+  def test_add_column_with_limit
+    assert_equal "ALTER TABLE `people` ADD `key` varchar(32)", add_column(:people, :key, :string, :limit => 32)
+  end
+
+  def test_drop_table_with_specific_database
+    assert_equal "DROP TABLE `otherdb`.`people`", drop_table('otherdb.people')
+  end
+
+  def test_add_timestamps
+    with_real_execute do
+      begin
+        ActiveRecord::Base.connection.create_table :delete_me
+        ActiveRecord::Base.connection.add_timestamps :delete_me
+        assert column_present?('delete_me', 'updated_at', 'datetime')
+        assert column_present?('delete_me', 'created_at', 'datetime')
+      ensure
+        ActiveRecord::Base.connection.drop_table :delete_me rescue nil
+      end
+    end
+  end
+
+  def test_remove_timestamps
+    with_real_execute do
+      begin
+        ActiveRecord::Base.connection.create_table :delete_me do |t|
+          t.timestamps
+        end
+        ActiveRecord::Base.connection.remove_timestamps :delete_me
+        assert !column_present?('delete_me', 'updated_at', 'datetime')
+        assert !column_present?('delete_me', 'created_at', 'datetime')
+      ensure
+        ActiveRecord::Base.connection.drop_table :delete_me rescue nil
+      end
+    end
+  end
+
+  def test_indexes_in_create
+    ActiveRecord::Base.connection.stubs(:table_exists?).with(:temp).returns(false)
+    ActiveRecord::Base.connection.stubs(:index_name_exists?).with(:index_temp_on_zip).returns(false)
+
+    expected = "CREATE TEMPORARY TABLE `temp` ( INDEX `index_temp_on_zip`  (`zip`) ) ENGINE=InnoDB AS SELECT id, name, zip FROM a_really_complicated_query"
+    actual = ActiveRecord::Base.connection.create_table(:temp, temporary: true, as: "SELECT id, name, zip FROM a_really_complicated_query") do |t|
+      t.index :zip
+    end
+
+    assert_equal expected, actual
+  end
+
+  private
+    def with_real_execute
+      ActiveRecord::Base.connection.singleton_class.class_eval do
+        alias_method :execute_with_stub, :execute
+        remove_method :execute
+        alias_method :execute, :execute_without_stub
+      end
+
+      yield
+    ensure
+      ActiveRecord::Base.connection.singleton_class.class_eval do
+        remove_method :execute
+        alias_method :execute, :execute_with_stub
+      end
+    end
+
+    def method_missing(method_symbol, *arguments)
+      ActiveRecord::Base.connection.send(method_symbol, *arguments)
+    end
+
+    def column_present?(table_name, column_name, type)
+      results = ActiveRecord::Base.connection.select_all("SHOW FIELDS FROM #{table_name} LIKE '#{column_name}'")
+      results.first && results.first['Type'] == type
+    end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb b/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb
new file mode 100644
index 0000000000..5e8065d80d
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb
@@ -0,0 +1,50 @@
+require "cases/helper"
+require 'models/topic'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2Adapter
+      class BindParameterTest < ActiveRecord::TestCase
+        fixtures :topics
+
+        def test_update_question_marks
+          str       = "foo?bar"
+          x         = Topic.first
+          x.title   = str
+          x.content = str
+          x.save!
+          x.reload
+          assert_equal str, x.title
+          assert_equal str, x.content
+        end
+
+        def test_create_question_marks
+          str = "foo?bar"
+          x   = Topic.create!(:title => str, :content => str)
+          x.reload
+          assert_equal str, x.title
+          assert_equal str, x.content
+        end
+
+        def test_update_null_bytes
+          str       = "foo\0bar"
+          x         = Topic.first
+          x.title   = str
+          x.content = str
+          x.save!
+          x.reload
+          assert_equal str, x.title
+          assert_equal str, x.content
+        end
+
+        def test_create_null_bytes
+          str = "foo\0bar"
+          x   = Topic.create!(:title => str, :content => str)
+          x.reload
+          assert_equal str, x.title
+          assert_equal str, x.content
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/boolean_test.rb b/activerecord/test/cases/adapters/mysql2/boolean_test.rb
new file mode 100644
index 0000000000..f3c711a64b
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/boolean_test.rb
@@ -0,0 +1,91 @@
+require "cases/helper"
+
+class Mysql2BooleanTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  class BooleanType < ActiveRecord::Base
+    self.table_name = "mysql_booleans"
+  end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table("mysql_booleans") do |t|
+      t.boolean "archived"
+      t.string "published", limit: 1
+    end
+    BooleanType.reset_column_information
+
+    @emulate_booleans = ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans
+  end
+
+  teardown do
+    emulate_booleans @emulate_booleans
+    @connection.drop_table "mysql_booleans"
+  end
+
+  test "column type with emulated booleans" do
+    emulate_booleans true
+
+    assert_equal :boolean, boolean_column.type
+    assert_equal :string, string_column.type
+  end
+
+  test "column type without emulated booleans" do
+    emulate_booleans false
+
+    assert_equal :integer, boolean_column.type
+    assert_equal :string, string_column.type
+  end
+
+  test "test type casting with emulated booleans" do
+    emulate_booleans true
+
+    boolean = BooleanType.create!(archived: true, published: true)
+    attributes = boolean.reload.attributes_before_type_cast
+
+    assert_equal 1, attributes["archived"]
+    assert_equal "1", attributes["published"]
+
+    assert_equal 1, @connection.type_cast(true, boolean_column)
+    assert_equal "1", @connection.type_cast(true, string_column)
+  end
+
+  test "test type casting without emulated booleans" do
+    emulate_booleans false
+
+    boolean = BooleanType.create!(archived: true, published: true)
+    attributes = boolean.reload.attributes_before_type_cast
+
+    assert_equal 1, attributes["archived"]
+    assert_equal "1", attributes["published"]
+
+    assert_equal 1, @connection.type_cast(true, boolean_column)
+    assert_equal "1", @connection.type_cast(true, string_column)
+  end
+
+  test "with booleans stored as 1 and 0" do
+    @connection.execute "INSERT INTO mysql_booleans(archived, published) VALUES(1, '1')"
+    boolean = BooleanType.first
+    assert_equal true, boolean.archived
+    assert_equal "1", boolean.published
+  end
+
+  test "with booleans stored as t" do
+    @connection.execute "INSERT INTO mysql_booleans(published) VALUES('t')"
+    boolean = BooleanType.first
+    assert_equal "t", boolean.published
+  end
+
+  def boolean_column
+    BooleanType.columns.find { |c| c.name == 'archived' }
+  end
+
+  def string_column
+    BooleanType.columns.find { |c| c.name == 'published' }
+  end
+
+  def emulate_booleans(value)
+    ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans = value
+    BooleanType.reset_column_information
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
new file mode 100644
index 0000000000..09bebf3071
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
@@ -0,0 +1,55 @@
+require "cases/helper"
+require 'models/person'
+
+class Mysql2CaseSensitivityTest < ActiveRecord::TestCase
+  class CollationTest < ActiveRecord::Base
+  end
+
+  repair_validations(CollationTest)
+
+  def test_columns_include_collation_different_from_table
+    assert_equal 'utf8_bin', CollationTest.columns_hash['string_cs_column'].collation
+    assert_equal 'utf8_general_ci', CollationTest.columns_hash['string_ci_column'].collation
+  end
+
+  def test_case_sensitive
+    assert !CollationTest.columns_hash['string_ci_column'].case_sensitive?
+    assert CollationTest.columns_hash['string_cs_column'].case_sensitive?
+  end
+
+  def test_case_insensitive_comparison_for_ci_column
+    CollationTest.validates_uniqueness_of(:string_ci_column, :case_sensitive => false)
+    CollationTest.create!(:string_ci_column => 'A')
+    invalid = CollationTest.new(:string_ci_column => 'a')
+    queries = assert_sql { invalid.save }
+    ci_uniqueness_query = queries.detect { |q| q.match(/string_ci_column/) }
+    assert_no_match(/lower/i, ci_uniqueness_query)
+  end
+
+  def test_case_insensitive_comparison_for_cs_column
+    CollationTest.validates_uniqueness_of(:string_cs_column, :case_sensitive => false)
+    CollationTest.create!(:string_cs_column => 'A')
+    invalid = CollationTest.new(:string_cs_column => 'a')
+    queries = assert_sql { invalid.save }
+    cs_uniqueness_query = queries.detect { |q| q.match(/string_cs_column/)}
+    assert_match(/lower/i, cs_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_ci_column
+    CollationTest.validates_uniqueness_of(:string_ci_column, :case_sensitive => true)
+    CollationTest.create!(:string_ci_column => 'A')
+    invalid = CollationTest.new(:string_ci_column => 'A')
+    queries = assert_sql { invalid.save }
+    ci_uniqueness_query = queries.detect { |q| q.match(/string_ci_column/) }
+    assert_match(/binary/i, ci_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_cs_column
+    CollationTest.validates_uniqueness_of(:string_cs_column, :case_sensitive => true)
+    CollationTest.create!(:string_cs_column => 'A')
+    invalid = CollationTest.new(:string_cs_column => 'A')
+    queries = assert_sql { invalid.save }
+    cs_uniqueness_query = queries.detect { |q| q.match(/string_cs_column/) }
+    assert_no_match(/binary/i, cs_uniqueness_query)
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/connection_test.rb b/activerecord/test/cases/adapters/mysql2/connection_test.rb
new file mode 100644
index 0000000000..3b35e69e0d
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/connection_test.rb
@@ -0,0 +1,116 @@
+require "cases/helper"
+require 'support/connection_helper'
+
+class MysqlConnectionTest < ActiveRecord::TestCase
+  include ConnectionHelper
+
+  def setup
+    super
+    @subscriber = SQLSubscriber.new
+    @subscription = ActiveSupport::Notifications.subscribe('sql.active_record', @subscriber)
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def teardown
+    ActiveSupport::Notifications.unsubscribe(@subscription)
+    super
+  end
+
+  def test_bad_connection
+    assert_raise ActiveRecord::NoDatabaseError do
+      configuration = ActiveRecord::Base.configurations['arunit'].merge(database: 'inexistent_activerecord_unittest')
+      connection = ActiveRecord::Base.mysql2_connection(configuration)
+      connection.exec_query('drop table if exists ex')
+    end
+  end
+
+  def test_no_automatic_reconnection_after_timeout
+    assert @connection.active?
+    @connection.update('set @@wait_timeout=1')
+    sleep 2
+    assert !@connection.active?
+
+    # Repair all fixture connections so other tests won't break.
+    @fixture_connections.each do |c|
+      c.verify!
+    end
+  end
+
+  def test_successful_reconnection_after_timeout_with_manual_reconnect
+    assert @connection.active?
+    @connection.update('set @@wait_timeout=1')
+    sleep 2
+    @connection.reconnect!
+    assert @connection.active?
+  end
+
+  def test_successful_reconnection_after_timeout_with_verify
+    assert @connection.active?
+    @connection.update('set @@wait_timeout=1')
+    sleep 2
+    @connection.verify!
+    assert @connection.active?
+  end
+
+  # TODO: Below is a straight up copy/paste from mysql/connection_test.rb
+  # I'm not sure what the correct way is to share these tests between
+  # adapters in minitest.
+  def test_mysql_default_in_strict_mode
+    result = @connection.exec_query "SELECT @@SESSION.sql_mode"
+    assert_equal [["STRICT_ALL_TABLES"]], result.rows
+  end
+
+  def test_mysql_strict_mode_disabled
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.merge({:strict => false}))
+      result = ActiveRecord::Base.connection.exec_query "SELECT @@SESSION.sql_mode"
+      assert_equal [['']], result.rows
+    end
+  end
+
+  def test_mysql_set_session_variable
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:default_week_format => 3}}))
+      session_mode = ActiveRecord::Base.connection.exec_query "SELECT @@SESSION.DEFAULT_WEEK_FORMAT"
+      assert_equal 3, session_mode.rows.first.first.to_i
+    end
+  end
+
+  def test_mysql_sql_mode_variable_overides_strict_mode
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { 'sql_mode' => 'ansi' }))
+      result = ActiveRecord::Base.connection.exec_query 'SELECT @@SESSION.sql_mode'
+      assert_not_equal [['STRICT_ALL_TABLES']], result.rows
+    end
+  end
+
+  def test_mysql_set_session_variable_to_default
+    run_without_connection do |orig_connection|
+      ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:default_week_format => :default}}))
+      global_mode = ActiveRecord::Base.connection.exec_query "SELECT @@GLOBAL.DEFAULT_WEEK_FORMAT"
+      session_mode = ActiveRecord::Base.connection.exec_query "SELECT @@SESSION.DEFAULT_WEEK_FORMAT"
+      assert_equal global_mode.rows, session_mode.rows
+    end
+  end
+
+  def test_logs_name_show_variable
+    @connection.show_variable 'foo'
+    assert_equal "SCHEMA", @subscriber.logged[0][1]
+  end
+
+  def test_logs_name_rename_column_sql
+    @connection.execute "CREATE TABLE `bar_baz` (`foo` varchar(255))"
+    @subscriber.logged.clear
+    @connection.send(:rename_column_sql, 'bar_baz', 'foo', 'foo2')
+    assert_equal "SCHEMA", @subscriber.logged[0][1]
+  ensure
+    @connection.execute "DROP TABLE `bar_baz`"
+  end
+
+  if mysql_56?
+    def test_quote_time_usec
+      assert_equal "'1970-01-01 00:00:00.000000'", @connection.quote(Time.at(0))
+      assert_equal "'1970-01-01 00:00:00.000000'", @connection.quote(Time.at(0).to_datetime)
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/enum_test.rb b/activerecord/test/cases/adapters/mysql2/enum_test.rb
new file mode 100644
index 0000000000..6dd9a5ec87
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/enum_test.rb
@@ -0,0 +1,10 @@
+require "cases/helper"
+
+class Mysql2EnumTest < ActiveRecord::TestCase
+  class EnumTest < ActiveRecord::Base
+  end
+
+  def test_enum_limit
+    assert_equal 6, EnumTest.columns.first.limit
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/explain_test.rb b/activerecord/test/cases/adapters/mysql2/explain_test.rb
new file mode 100644
index 0000000000..675703caa1
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/explain_test.rb
@@ -0,0 +1,26 @@
+require "cases/helper"
+require 'models/developer'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2Adapter
+      class ExplainTest < ActiveRecord::TestCase
+        fixtures :developers
+
+        def test_explain_for_one_query
+          explain = Developer.where(:id => 1).explain
+          assert_match %(EXPLAIN for: SELECT `developers`.* FROM `developers` WHERE `developers`.`id` = 1), explain
+          assert_match %r(developers |.* const), explain
+        end
+
+        def test_explain_with_eager_loading
+          explain = Developer.where(:id => 1).includes(:audit_logs).explain
+          assert_match %(EXPLAIN for: SELECT `developers`.* FROM `developers` WHERE `developers`.`id` = 1), explain
+          assert_match %r(developers |.* const), explain
+          assert_match %(EXPLAIN for: SELECT `audit_logs`.* FROM `audit_logs` WHERE `audit_logs`.`developer_id` IN (1)), explain
+          assert_match %r(audit_logs |.* ALL), explain
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/reserved_word_test.rb b/activerecord/test/cases/adapters/mysql2/reserved_word_test.rb
new file mode 100644
index 0000000000..799d927ee4
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/reserved_word_test.rb
@@ -0,0 +1,152 @@
+require "cases/helper"
+
+class Group < ActiveRecord::Base
+  Group.table_name = 'group'
+  belongs_to :select
+  has_one :values
+end
+
+class Select < ActiveRecord::Base
+  Select.table_name = 'select'
+  has_many :groups
+end
+
+class Values < ActiveRecord::Base
+  Values.table_name = 'values'
+end
+
+class Distinct < ActiveRecord::Base
+  Distinct.table_name = 'distinct'
+  has_and_belongs_to_many :selects
+  has_many :values, :through => :groups
+end
+
+# a suite of tests to ensure the ConnectionAdapters#MysqlAdapter can handle tables with
+# reserved word names (ie: group, order, values, etc...)
+class MysqlReservedWordTest < ActiveRecord::TestCase
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    # we call execute directly here (and do similar below) because ActiveRecord::Base#create_table()
+    # will fail with these table names if these test cases fail
+
+    create_tables_directly 'group'=>'id int auto_increment primary key, `order` varchar(255), select_id int',
+      'select'=>'id int auto_increment primary key',
+      'values'=>'id int auto_increment primary key, group_id int',
+      'distinct'=>'id int auto_increment primary key',
+      'distinct_select'=>'distinct_id int, select_id int'
+  end
+
+  teardown do
+    drop_tables_directly ['group', 'select', 'values', 'distinct', 'distinct_select', 'order']
+  end
+
+  # create tables with reserved-word names and columns
+  def test_create_tables
+    assert_nothing_raised {
+      @connection.create_table :order do |t|
+        t.column :group, :string
+      end
+    }
+  end
+
+  # rename tables with reserved-word names
+  def test_rename_tables
+    assert_nothing_raised { @connection.rename_table(:group, :order) }
+  end
+
+  # alter column with a reserved-word name in a table with a reserved-word name
+  def test_change_columns
+    assert_nothing_raised { @connection.change_column_default(:group, :order, 'whatever') }
+    #the quoting here will reveal any double quoting issues in change_column's interaction with the column method in the adapter
+    assert_nothing_raised { @connection.change_column('group', 'order', :Int, :default => 0) }
+    assert_nothing_raised { @connection.rename_column(:group, :order, :values) }
+  end
+
+  # introspect table with reserved word name
+  def test_introspect
+    assert_nothing_raised { @connection.columns(:group) }
+    assert_nothing_raised { @connection.indexes(:group) }
+  end
+
+  #fixtures
+  self.use_instantiated_fixtures = true
+  self.use_transactional_fixtures = false
+
+  #activerecord model class with reserved-word table name
+  def test_activerecord_model
+    create_test_fixtures :select, :distinct, :group, :values, :distinct_select
+    x = nil
+    assert_nothing_raised { x = Group.new }
+    x.order = 'x'
+    assert_nothing_raised { x.save }
+    x.order = 'y'
+    assert_nothing_raised { x.save }
+    assert_nothing_raised { Group.find_by_order('y') }
+    assert_nothing_raised { Group.find(1) }
+  end
+
+  # has_one association with reserved-word table name
+  def test_has_one_associations
+    create_test_fixtures :select, :distinct, :group, :values, :distinct_select
+    v = nil
+    assert_nothing_raised { v = Group.find(1).values }
+    assert_equal 2, v.id
+  end
+
+  # belongs_to association with reserved-word table name
+  def test_belongs_to_associations
+    create_test_fixtures :select, :distinct, :group, :values, :distinct_select
+    gs = nil
+    assert_nothing_raised { gs = Select.find(2).groups }
+    assert_equal gs.length, 2
+    assert(gs.collect{|x| x.id}.sort == [2, 3])
+  end
+
+  # has_and_belongs_to_many with reserved-word table name
+  def test_has_and_belongs_to_many
+    create_test_fixtures :select, :distinct, :group, :values, :distinct_select
+    s = nil
+    assert_nothing_raised { s = Distinct.find(1).selects }
+    assert_equal s.length, 2
+    assert(s.collect{|x|x.id}.sort == [1, 2])
+  end
+
+  # activerecord model introspection with reserved-word table and column names
+  def test_activerecord_introspection
+    assert_nothing_raised { Group.table_exists? }
+    assert_nothing_raised { Group.columns }
+  end
+
+  # Calculations
+  def test_calculations_work_with_reserved_words
+    assert_nothing_raised { Group.count }
+  end
+
+  def test_associations_work_with_reserved_words
+    assert_nothing_raised { Select.all.merge!(:includes => [:groups]).to_a }
+  end
+
+  #the following functions were added to DRY test cases
+
+  private
+  # custom fixture loader, uses FixtureSet#create_fixtures and appends base_path to the current file's path
+  def create_test_fixtures(*fixture_names)
+    ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT + "/reserved_words", fixture_names)
+  end
+
+  # custom drop table, uses execute on connection to drop a table if it exists. note: escapes table_name
+  def drop_tables_directly(table_names, connection = @connection)
+    table_names.each do |name|
+      connection.execute("DROP TABLE IF EXISTS `#{name}`")
+    end
+  end
+
+  # custom create table, uses execute on connection to create a table, note: escapes table_name, does NOT escape columns
+  def create_tables_directly (tables, connection = @connection)
+    tables.each do |table_name, column_properties|
+      connection.execute("CREATE TABLE `#{table_name}` ( #{column_properties} )")
+    end
+  end
+
+end
diff --git a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
new file mode 100644
index 0000000000..9c49599d34
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
@@ -0,0 +1,39 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2Adapter
+      class SchemaMigrationsTest < ActiveRecord::TestCase
+        def test_renaming_index_on_foreign_key
+          connection.add_index "engines", "car_id"
+          connection.add_foreign_key :engines, :cars, name: "fk_engines_cars"
+
+          connection.rename_index("engines", "index_engines_on_car_id", "idx_renamed")
+          assert_equal ["idx_renamed"], connection.indexes("engines").map(&:name)
+        ensure
+          connection.remove_foreign_key :engines, name: "fk_engines_cars"
+        end
+
+        def test_initializes_schema_migrations_for_encoding_utf8mb4
+          smtn = ActiveRecord::Migrator.schema_migrations_table_name
+          connection.drop_table(smtn) if connection.table_exists?(smtn)
+
+          config = connection.instance_variable_get(:@config)
+          original_encoding = config[:encoding]
+
+          config[:encoding] = 'utf8mb4'
+          connection.initialize_schema_migrations_table
+
+          assert connection.column_exists?(smtn, :version, :string, limit: Mysql2Adapter::MAX_INDEX_LENGTH_FOR_UTF8MB4)
+        ensure
+          config[:encoding] = original_encoding
+        end
+
+        private
+        def connection
+          @connection ||= ActiveRecord::Base.connection
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/schema_test.rb b/activerecord/test/cases/adapters/mysql2/schema_test.rb
new file mode 100644
index 0000000000..43c9116b5a
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/schema_test.rb
@@ -0,0 +1,79 @@
+require "cases/helper"
+require 'models/post'
+require 'models/comment'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2SchemaTest < ActiveRecord::TestCase
+      fixtures :posts
+
+      def setup
+        @connection = ActiveRecord::Base.connection
+        db          = Post.connection_pool.spec.config[:database]
+        table       = Post.table_name
+        @db_name    = db
+
+        @omgpost = Class.new(ActiveRecord::Base) do
+          self.table_name = "#{db}.#{table}"
+          def self.name; 'Post'; end
+        end
+      end
+
+      def test_schema
+        assert @omgpost.first
+      end
+
+      def test_primary_key
+        assert_equal 'id', @omgpost.primary_key
+      end
+
+      def test_table_exists?
+        name = @omgpost.table_name
+        assert @connection.table_exists?(name), "#{name} table should exist"
+      end
+
+      def test_table_exists_wrong_schema
+        assert(!@connection.table_exists?("#{@db_name}.zomg"), "table should not exist")
+      end
+
+      def test_tables_quoting
+        @connection.tables(nil, "foo-bar", nil)
+        flunk
+      rescue => e
+        # assertion for *quoted* database properly
+        assert_match(/database 'foo-bar'/, e.inspect)
+      end
+
+      def test_dump_indexes
+        index_a_name = 'index_key_tests_on_snack'
+        index_b_name = 'index_key_tests_on_pizza'
+        index_c_name = 'index_key_tests_on_awesome'
+
+        table = 'key_tests'
+
+        indexes = @connection.indexes(table).sort_by {|i| i.name}
+        assert_equal 3,indexes.size
+
+        index_a = indexes.select{|i| i.name == index_a_name}[0]
+        index_b = indexes.select{|i| i.name == index_b_name}[0]
+        index_c = indexes.select{|i| i.name == index_c_name}[0]
+        assert_equal :btree, index_a.using
+        assert_nil index_a.type
+        assert_equal :btree, index_b.using
+        assert_nil index_b.type
+
+        assert_nil index_c.using
+        assert_equal :fulltext, index_c.type
+      end
+
+      def test_drop_temporary_table
+        @connection.transaction do
+          @connection.create_table(:temp_table, temporary: true)
+          # if it doesn't properly say DROP TEMPORARY TABLE, the transaction commit
+          # will complain that no transaction is active
+          @connection.drop_table(:temp_table, temporary: true)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/sql_types_test.rb b/activerecord/test/cases/adapters/mysql2/sql_types_test.rb
new file mode 100644
index 0000000000..1ddb1b91c9
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/sql_types_test.rb
@@ -0,0 +1,14 @@
+require "cases/helper"
+
+class SqlTypesTest < ActiveRecord::TestCase
+  def test_binary_types
+    assert_equal 'varbinary(64)', type_to_sql(:binary, 64)
+    assert_equal 'varbinary(4095)', type_to_sql(:binary, 4095)
+    assert_equal 'blob(4096)', type_to_sql(:binary, 4096)
+    assert_equal 'blob', type_to_sql(:binary)
+  end
+
+  def type_to_sql(*args)
+    ActiveRecord::Base.connection.type_to_sql(*args)
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/active_schema_test.rb b/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
new file mode 100644
index 0000000000..3808db5141
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
@@ -0,0 +1,58 @@
+require 'cases/helper'
+
+class PostgresqlActiveSchemaTest < ActiveRecord::TestCase
+  def setup
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.class_eval do
+      def execute(sql, name = nil) sql end
+    end
+  end
+
+  teardown do
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.class_eval do
+      remove_method :execute
+    end
+  end
+
+  def test_create_database_with_encoding
+    assert_equal %(CREATE DATABASE "matt" ENCODING = 'utf8'), create_database(:matt)
+    assert_equal %(CREATE DATABASE "aimonetti" ENCODING = 'latin1'), create_database(:aimonetti, :encoding => :latin1)
+    assert_equal %(CREATE DATABASE "aimonetti" ENCODING = 'latin1'), create_database(:aimonetti, 'encoding' => :latin1)
+  end
+
+  def test_create_database_with_collation_and_ctype
+    assert_equal %(CREATE DATABASE "aimonetti" ENCODING = 'UTF8' LC_COLLATE = 'ja_JP.UTF8' LC_CTYPE = 'ja_JP.UTF8'), create_database(:aimonetti, :encoding => :"UTF8", :collation => :"ja_JP.UTF8", :ctype => :"ja_JP.UTF8")
+  end
+
+  def test_add_index
+    # add_index calls index_name_exists? which can't work since execute is stubbed
+    ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.stubs(:index_name_exists?).returns(false)
+
+    expected = %(CREATE UNIQUE INDEX  "index_people_on_last_name" ON "people"  ("last_name") WHERE state = 'active')
+    assert_equal expected, add_index(:people, :last_name, :unique => true, :where => "state = 'active'")
+
+    expected = %(CREATE  INDEX CONCURRENTLY "index_people_on_last_name" ON "people"  ("last_name"))
+    assert_equal expected, add_index(:people, :last_name, algorithm: :concurrently)
+
+    %w(gin gist hash btree).each do |type|
+      expected = %(CREATE  INDEX  "index_people_on_last_name" ON "people" USING #{type} ("last_name"))
+      assert_equal expected, add_index(:people, :last_name, using: type)
+
+      expected = %(CREATE  INDEX CONCURRENTLY "index_people_on_last_name" ON "people" USING #{type} ("last_name"))
+      assert_equal expected, add_index(:people, :last_name, using: type, algorithm: :concurrently)
+    end
+
+    assert_raise ArgumentError do
+      add_index(:people, :last_name, algorithm: :copy)
+    end
+    expected = %(CREATE UNIQUE INDEX  "index_people_on_last_name" ON "people" USING gist ("last_name"))
+    assert_equal expected, add_index(:people, :last_name, :unique => true, :using => :gist)
+
+    expected = %(CREATE UNIQUE INDEX  "index_people_on_last_name" ON "people" USING gist ("last_name") WHERE state = 'active')
+    assert_equal expected, add_index(:people, :last_name, :unique => true, :where => "state = 'active'", :using => :gist)
+  end
+
+  private
+    def method_missing(method_symbol, *arguments)
+      ActiveRecord::Base.connection.send(method_symbol, *arguments)
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/array_test.rb b/activerecord/test/cases/adapters/postgresql/array_test.rb
new file mode 100644
index 0000000000..8df1b7d18c
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/array_test.rb
@@ -0,0 +1,275 @@
+# encoding: utf-8
+require "cases/helper"
+
+class PostgresqlArrayTest < ActiveRecord::TestCase
+  include InTimeZone
+  OID = ActiveRecord::ConnectionAdapters::PostgreSQL::OID
+
+  class PgArray < ActiveRecord::Base
+    self.table_name = 'pg_arrays'
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    unless @connection.extension_enabled?('hstore')
+      @connection.enable_extension 'hstore'
+      @connection.commit_db_transaction
+    end
+
+    @connection.reconnect!
+
+    @connection.transaction do
+      @connection.create_table('pg_arrays') do |t|
+        t.string 'tags', array: true
+        t.integer 'ratings', array: true
+        t.datetime :datetimes, array: true
+        t.hstore :hstores, array: true
+      end
+    end
+    @column = PgArray.columns_hash['tags']
+  end
+
+  teardown do
+    @connection.execute 'drop table if exists pg_arrays'
+  end
+
+  def test_column
+    assert_equal :string, @column.type
+    assert_equal "character varying", @column.sql_type
+    assert @column.array
+    assert_not @column.number?
+    assert_not @column.binary?
+
+    ratings_column = PgArray.columns_hash['ratings']
+    assert_equal :integer, ratings_column.type
+    assert ratings_column.array
+    assert_not ratings_column.number?
+  end
+
+  def test_default
+    @connection.add_column 'pg_arrays', 'score', :integer, array: true, default: [4, 4, 2]
+    PgArray.reset_column_information
+
+    assert_equal([4, 4, 2], PgArray.column_defaults['score'])
+    assert_equal([4, 4, 2], PgArray.new.score)
+  ensure
+    PgArray.reset_column_information
+  end
+
+  def test_default_strings
+    @connection.add_column 'pg_arrays', 'names', :string, array: true, default: ["foo", "bar"]
+    PgArray.reset_column_information
+
+    assert_equal(["foo", "bar"], PgArray.column_defaults['names'])
+    assert_equal(["foo", "bar"], PgArray.new.names)
+  ensure
+    PgArray.reset_column_information
+  end
+
+  def test_change_column_with_array
+    @connection.add_column :pg_arrays, :snippets, :string, array: true, default: []
+    @connection.change_column :pg_arrays, :snippets, :text, array: true, default: []
+
+    PgArray.reset_column_information
+    column = PgArray.columns_hash['snippets']
+
+    assert_equal :text, column.type
+    assert_equal [], PgArray.column_defaults['snippets']
+    assert column.array
+  end
+
+  def test_change_column_cant_make_non_array_column_to_array
+    @connection.add_column :pg_arrays, :a_string, :string
+    assert_raises ActiveRecord::StatementInvalid do
+      @connection.transaction do
+        @connection.change_column :pg_arrays, :a_string, :string, array: true
+      end
+    end
+  end
+
+  def test_change_column_default_with_array
+    @connection.change_column_default :pg_arrays, :tags, []
+
+    PgArray.reset_column_information
+    assert_equal [], PgArray.column_defaults['tags']
+  end
+
+  def test_type_cast_array
+    assert_equal(['1', '2', '3'], @column.type_cast_from_database('{1,2,3}'))
+    assert_equal([], @column.type_cast_from_database('{}'))
+    assert_equal([nil], @column.type_cast_from_database('{NULL}'))
+  end
+
+  def test_type_cast_integers
+    x = PgArray.new(ratings: ['1', '2'])
+
+    assert_equal([1, 2], x.ratings)
+
+    x.save!
+    x.reload
+
+    assert_equal([1, 2], x.ratings)
+  end
+
+  def test_select_with_strings
+    @connection.execute "insert into pg_arrays (tags) VALUES ('{1,2,3}')"
+    x = PgArray.first
+    assert_equal(['1','2','3'], x.tags)
+  end
+
+  def test_rewrite_with_strings
+    @connection.execute "insert into pg_arrays (tags) VALUES ('{1,2,3}')"
+    x = PgArray.first
+    x.tags = ['1','2','3','4']
+    x.save!
+    assert_equal ['1','2','3','4'], x.reload.tags
+  end
+
+  def test_select_with_integers
+    @connection.execute "insert into pg_arrays (ratings) VALUES ('{1,2,3}')"
+    x = PgArray.first
+    assert_equal([1, 2, 3], x.ratings)
+  end
+
+  def test_rewrite_with_integers
+    @connection.execute "insert into pg_arrays (ratings) VALUES ('{1,2,3}')"
+    x = PgArray.first
+    x.ratings = [2, '3', 4]
+    x.save!
+    assert_equal [2, 3, 4], x.reload.ratings
+  end
+
+  def test_multi_dimensional_with_strings
+    assert_cycle(:tags, [[['1'], ['2']], [['2'], ['3']]])
+  end
+
+  def test_with_empty_strings
+    assert_cycle(:tags, [ '1', '2', '', '4', '', '5' ])
+  end
+
+  def test_with_multi_dimensional_empty_strings
+    assert_cycle(:tags, [[['1', '2'], ['', '4'], ['', '5']]])
+  end
+
+  def test_with_arbitrary_whitespace
+    assert_cycle(:tags, [[['1', '2'], ['    ', '4'], ['    ', '5']]])
+  end
+
+  def test_multi_dimensional_with_integers
+    assert_cycle(:ratings, [[[1], [7]], [[8], [10]]])
+  end
+
+  def test_strings_with_quotes
+    assert_cycle(:tags, ['this has','some "s that need to be escaped"'])
+  end
+
+  def test_strings_with_commas
+    assert_cycle(:tags, ['this,has','many,values'])
+  end
+
+  def test_strings_with_array_delimiters
+    assert_cycle(:tags, ['{','}'])
+  end
+
+  def test_strings_with_null_strings
+    assert_cycle(:tags, ['NULL','NULL'])
+  end
+
+  def test_contains_nils
+    assert_cycle(:tags, ['1',nil,nil])
+  end
+
+  def test_insert_fixture
+    tag_values = ["val1", "val2", "val3_with_'_multiple_quote_'_chars"]
+    @connection.insert_fixture({"tags" => tag_values}, "pg_arrays" )
+    assert_equal(PgArray.last.tags, tag_values)
+  end
+
+  def test_attribute_for_inspect_for_array_field
+    record = PgArray.new { |a| a.ratings = (1..11).to_a }
+    assert_equal("[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ...]", record.attribute_for_inspect(:ratings))
+  end
+
+  def test_escaping
+    unknown = 'foo\\",bar,baz,\\'
+    tags = ["hello_#{unknown}"]
+    ar = PgArray.create!(tags: tags)
+    ar.reload
+    assert_equal tags, ar.tags
+  end
+
+  def test_string_quoting_rules_match_pg_behavior
+    tags = ["", "one{", "two}", %(three"), "four\\", "five ", "six\t", "seven\n", "eight,", "nine", "ten\r", "NULL"]
+    x = PgArray.create!(tags: tags)
+    x.reload
+
+    assert_equal x.tags_before_type_cast, PgArray.columns_hash['tags'].type_cast_for_database(tags)
+  end
+
+  def test_quoting_non_standard_delimiters
+    strings = ["hello,", "world;"]
+    comma_delim = OID::Array.new(ActiveRecord::Type::String.new, ',')
+    semicolon_delim = OID::Array.new(ActiveRecord::Type::String.new, ';')
+
+    assert_equal %({"hello,",world;}), comma_delim.type_cast_for_database(strings)
+    assert_equal %({hello,;"world;"}), semicolon_delim.type_cast_for_database(strings)
+  end
+
+  def test_mutate_array
+    x = PgArray.create!(tags: %w(one two))
+
+    x.tags << "three"
+    x.save!
+    x.reload
+
+    assert_equal %w(one two three), x.tags
+    assert_not x.changed?
+  end
+
+  def test_mutate_value_in_array
+    x = PgArray.create!(hstores: [{ a: 'a' }, { b: 'b' }])
+
+    x.hstores.first['a'] = 'c'
+    x.save!
+    x.reload
+
+    assert_equal [{ 'a' => 'c' }, { 'b' => 'b' }], x.hstores
+    assert_not x.changed?
+  end
+
+  def test_datetime_with_timezone_awareness
+    tz = "Pacific Time (US & Canada)"
+
+    in_time_zone tz do
+      PgArray.reset_column_information
+      time_string = Time.current.to_s
+      time = Time.zone.parse(time_string)
+
+      record = PgArray.new(datetimes: [time_string])
+      assert_equal [time], record.datetimes
+      assert_equal ActiveSupport::TimeZone[tz], record.datetimes.first.time_zone
+
+      record.save!
+      record.reload
+
+      assert_equal [time], record.datetimes
+      assert_equal ActiveSupport::TimeZone[tz], record.datetimes.first.time_zone
+    end
+  end
+
+  private
+  def assert_cycle field, array
+    # test creation
+    x = PgArray.create!(field => array)
+    x.reload
+    assert_equal(array, x.public_send(field))
+
+    # test updating
+    x = PgArray.create!(field => [])
+    x.public_send("#{field}=", array)
+    x.save!
+    x.reload
+    assert_equal(array, x.public_send(field))
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/bit_string_test.rb b/activerecord/test/cases/adapters/postgresql/bit_string_test.rb
new file mode 100644
index 0000000000..72222c01fd
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/bit_string_test.rb
@@ -0,0 +1,76 @@
+# -*- coding: utf-8 -*-
+require "cases/helper"
+require 'support/connection_helper'
+require 'support/schema_dumping_helper'
+
+class PostgresqlBitStringTest < ActiveRecord::TestCase
+  include ConnectionHelper
+  include SchemaDumpingHelper
+
+  class PostgresqlBitString < ActiveRecord::Base; end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table('postgresql_bit_strings', :force => true) do |t|
+      t.bit :a_bit, default: "00000011", limit: 8
+      t.bit_varying :a_bit_varying, default: "0011", limit: 4
+    end
+  end
+
+  def teardown
+    return unless @connection
+    @connection.execute 'DROP TABLE IF EXISTS postgresql_bit_strings'
+  end
+
+  def test_bit_string_column
+    column = PostgresqlBitString.columns_hash["a_bit"]
+    assert_equal :bit, column.type
+    assert_equal "bit(8)", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_bit_string_varying_column
+    column = PostgresqlBitString.columns_hash["a_bit_varying"]
+    assert_equal :bit_varying, column.type
+    assert_equal "bit varying(4)", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_default
+    assert_equal "00000011", PostgresqlBitString.column_defaults['a_bit']
+    assert_equal "00000011", PostgresqlBitString.new.a_bit
+
+    assert_equal "0011", PostgresqlBitString.column_defaults['a_bit_varying']
+    assert_equal "0011", PostgresqlBitString.new.a_bit_varying
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("postgresql_bit_strings")
+    assert_match %r{t\.bit\s+"a_bit",\s+limit: 8,\s+default: "00000011"$}, output
+    assert_match %r{t\.bit_varying\s+"a_bit_varying",\s+limit: 4,\s+default: "0011"$}, output
+  end
+
+  def test_assigning_invalid_hex_string_raises_exception
+    assert_raises(ActiveRecord::StatementInvalid) { PostgresqlBitString.create! a_bit: "FF" }
+    assert_raises(ActiveRecord::StatementInvalid) { PostgresqlBitString.create! a_bit_varying: "FF" }
+  end
+
+  def test_roundtrip
+    PostgresqlBitString.create! a_bit: "00001010", a_bit_varying: "0101"
+    record = PostgresqlBitString.first
+    assert_equal "00001010", record.a_bit
+    assert_equal "0101", record.a_bit_varying
+
+    record.a_bit = "11111111"
+    record.a_bit_varying = "0xF"
+    record.save!
+
+    assert record.reload
+    assert_equal "11111111", record.a_bit
+    assert_equal "1111", record.a_bit_varying
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/bytea_test.rb b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
new file mode 100644
index 0000000000..7872f91943
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
@@ -0,0 +1,118 @@
+# encoding: utf-8
+require "cases/helper"
+
+class PostgresqlByteaTest < ActiveRecord::TestCase
+  class ByteaDataType < ActiveRecord::Base
+    self.table_name = 'bytea_data_type'
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    begin
+      @connection.transaction do
+        @connection.create_table('bytea_data_type') do |t|
+          t.binary 'payload'
+          t.binary 'serialized'
+        end
+      end
+    end
+    @column = ByteaDataType.columns_hash['payload']
+    assert(@column.is_a?(ActiveRecord::ConnectionAdapters::PostgreSQLColumn))
+  end
+
+  teardown do
+    @connection.execute 'drop table if exists bytea_data_type'
+  end
+
+  def test_column
+    assert_equal :binary, @column.type
+  end
+
+  def test_type_cast_binary_converts_the_encoding
+    assert @column
+
+    data = "\u001F\x8B"
+    assert_equal('UTF-8', data.encoding.name)
+    assert_equal('ASCII-8BIT', @column.type_cast_from_database(data).encoding.name)
+  end
+
+  def test_type_cast_binary_value
+    data = "\u001F\x8B".force_encoding("BINARY")
+    assert_equal(data, @column.type_cast_from_database(data))
+  end
+
+  def test_type_case_nil
+    assert_equal(nil, @column.type_cast_from_database(nil))
+  end
+
+  def test_read_value
+    data = "\u001F"
+    @connection.execute "insert into bytea_data_type (payload) VALUES ('#{data}')"
+    record = ByteaDataType.first
+    assert_equal(data, record.payload)
+    record.delete
+  end
+
+  def test_read_nil_value
+    @connection.execute "insert into bytea_data_type (payload) VALUES (null)"
+    record = ByteaDataType.first
+    assert_equal(nil, record.payload)
+    record.delete
+  end
+
+  def test_write_value
+    data = "\u001F"
+    record = ByteaDataType.create(payload: data)
+    assert_not record.new_record?
+    assert_equal(data, record.payload)
+  end
+
+  def test_via_to_sql
+    data = "'\u001F\\"
+    ByteaDataType.create(payload: data)
+    sql = ByteaDataType.where(payload: data).select(:payload).to_sql
+    result = @connection.query(sql)
+    assert_equal([[data]], result)
+  end
+
+  def test_via_to_sql_with_complicating_connection
+    Thread.new do
+      other_conn = ActiveRecord::Base.connection
+      other_conn.execute('SET standard_conforming_strings = off')
+    end.join
+
+    test_via_to_sql
+  end
+
+  def test_write_binary
+    data = File.read(File.join(File.dirname(__FILE__), '..', '..', '..', 'assets', 'example.log'))
+    assert(data.size > 1)
+    record = ByteaDataType.create(payload: data)
+    assert_not record.new_record?
+    assert_equal(data, record.payload)
+    assert_equal(data, ByteaDataType.where(id: record.id).first.payload)
+  end
+
+  def test_write_nil
+    record = ByteaDataType.create(payload: nil)
+    assert_not record.new_record?
+    assert_equal(nil, record.payload)
+    assert_equal(nil, ByteaDataType.where(id: record.id).first.payload)
+  end
+
+  class Serializer
+    def load(str); str; end
+    def dump(str); str; end
+  end
+
+  def test_serialize
+    klass = Class.new(ByteaDataType) {
+      serialize :serialized, Serializer.new
+    }
+    obj = klass.new
+    obj.serialized = "hello world"
+    obj.save!
+    obj.reload
+    assert_equal "hello world", obj.serialized
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/citext_test.rb b/activerecord/test/cases/adapters/postgresql/citext_test.rb
new file mode 100644
index 0000000000..2acb64f81c
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/citext_test.rb
@@ -0,0 +1,76 @@
+# encoding: utf-8
+require 'cases/helper'
+
+if ActiveRecord::Base.connection.supports_extensions?
+  class PostgresqlCitextTest < ActiveRecord::TestCase
+    class Citext < ActiveRecord::Base
+      self.table_name = 'citexts'
+    end
+
+    def setup
+      @connection = ActiveRecord::Base.connection
+
+      unless @connection.extension_enabled?('citext')
+        @connection.enable_extension 'citext'
+        @connection.commit_db_transaction
+      end
+
+      @connection.reconnect!
+
+      @connection.create_table('citexts') do |t|
+        t.citext 'cival'
+      end
+    end
+
+    teardown do
+      @connection.execute 'DROP TABLE IF EXISTS citexts;'
+      @connection.execute 'DROP EXTENSION IF EXISTS citext CASCADE;'
+    end
+
+    def test_citext_enabled
+      assert @connection.extension_enabled?('citext')
+    end
+
+    def test_column
+      column = Citext.columns_hash['cival']
+      assert_equal :citext, column.type
+      assert_equal 'citext', column.sql_type
+      assert_not column.number?
+      assert_not column.binary?
+      assert_not column.array
+    end
+
+    def test_change_table_supports_json
+      @connection.transaction do
+        @connection.change_table('citexts') do |t|
+          t.citext 'username'
+        end
+        Citext.reset_column_information
+        column = Citext.columns_hash['username']
+        assert_equal :citext, column.type
+
+        raise ActiveRecord::Rollback # reset the schema change
+      end
+    ensure
+      Citext.reset_column_information
+    end
+
+    def test_write
+      x = Citext.new(cival: 'Some CI Text')
+      x.save!
+      citext = Citext.first
+      assert_equal "Some CI Text", citext.cival
+
+      citext.cival = "Some NEW CI Text"
+      citext.save!
+
+      assert_equal "Some NEW CI Text", citext.reload.cival
+    end
+
+    def test_select_case_insensitive
+      @connection.execute "insert into citexts (cival) values('Cased Text')"
+      x = Citext.where(cival: 'cased text').first
+      assert_equal 'Cased Text', x.cival
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/composite_test.rb b/activerecord/test/cases/adapters/postgresql/composite_test.rb
new file mode 100644
index 0000000000..cfab5ca902
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/composite_test.rb
@@ -0,0 +1,131 @@
+# -*- coding: utf-8 -*-
+require "cases/helper"
+require 'support/connection_helper'
+
+module PostgresqlCompositeBehavior
+  include ConnectionHelper
+
+  class PostgresqlComposite < ActiveRecord::Base
+    self.table_name = "postgresql_composites"
+  end
+
+  def setup
+    super
+
+    @connection = ActiveRecord::Base.connection
+    @connection.transaction do
+      @connection.execute <<-SQL
+         CREATE TYPE full_address AS
+         (
+             city VARCHAR(90),
+             street VARCHAR(90)
+         );
+        SQL
+      @connection.create_table('postgresql_composites') do |t|
+        t.column :address, :full_address
+      end
+    end
+  end
+
+  def teardown
+    super
+
+    @connection.execute 'DROP TABLE IF EXISTS postgresql_composites'
+    @connection.execute 'DROP TYPE IF EXISTS full_address'
+    reset_connection
+    PostgresqlComposite.reset_column_information
+  end
+end
+
+# Composites are mapped to `OID::Identity` by default. The user is informed by a warning like:
+#   "unknown OID 5653508: failed to recognize type of 'address'. It will be treated as String."
+# To take full advantage of composite types, we suggest you register your own +OID::Type+.
+# See PostgresqlCompositeWithCustomOIDTest
+class PostgresqlCompositeTest < ActiveRecord::TestCase
+  include PostgresqlCompositeBehavior
+
+  def test_column
+    ensure_warning_is_issued
+
+    column = PostgresqlComposite.columns_hash["address"]
+    assert_nil column.type
+    assert_equal "full_address", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_composite_mapping
+    ensure_warning_is_issued
+
+    @connection.execute "INSERT INTO postgresql_composites VALUES (1, ROW('Paris', 'Champs-Élysées'));"
+    composite = PostgresqlComposite.first
+    assert_equal "(Paris,Champs-Élysées)", composite.address
+
+    composite.address = "(Paris,Rue Basse)"
+    composite.save!
+
+    assert_equal '(Paris,"Rue Basse")', composite.reload.address
+  end
+
+  private
+  def ensure_warning_is_issued
+    warning = capture(:stderr) do
+      PostgresqlComposite.columns_hash
+    end
+    assert_match(/unknown OID \d+: failed to recognize type of 'address'\. It will be treated as String\./, warning)
+  end
+end
+
+class PostgresqlCompositeWithCustomOIDTest < ActiveRecord::TestCase
+  include PostgresqlCompositeBehavior
+
+  class FullAddressType < ActiveRecord::Type::Value
+    def type; :full_address end
+
+    def type_cast_from_database(value)
+      if value =~ /\("?([^",]*)"?,"?([^",]*)"?\)/
+        FullAddress.new($1, $2)
+      end
+    end
+
+    def type_cast_from_user(value)
+      value
+    end
+
+    def type_cast_for_database(value)
+      return if value.nil?
+      "(#{value.city},#{value.street})"
+    end
+  end
+
+  FullAddress = Struct.new(:city, :street)
+
+  def setup
+    super
+
+    @connection.type_map.register_type "full_address", FullAddressType.new
+  end
+
+  def test_column
+    column = PostgresqlComposite.columns_hash["address"]
+    assert_equal :full_address, column.type
+    assert_equal "full_address", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_composite_mapping
+    @connection.execute "INSERT INTO postgresql_composites VALUES (1, ROW('Paris', 'Champs-Élysées'));"
+    composite = PostgresqlComposite.first
+    assert_equal "Paris", composite.address.city
+    assert_equal "Champs-Élysées", composite.address.street
+
+    composite.address = FullAddress.new("Paris", "Rue Basse")
+    composite.save!
+
+    assert_equal 'Paris', composite.reload.address.city
+    assert_equal 'Rue Basse', composite.reload.address.street
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/connection_test.rb b/activerecord/test/cases/adapters/postgresql/connection_test.rb
new file mode 100644
index 0000000000..d26cda46fa
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/connection_test.rb
@@ -0,0 +1,205 @@
+require "cases/helper"
+require 'support/connection_helper'
+
+module ActiveRecord
+  class PostgresqlConnectionTest < ActiveRecord::TestCase
+    include ConnectionHelper
+
+    class NonExistentTable < ActiveRecord::Base
+    end
+
+    def setup
+      super
+      @subscriber = SQLSubscriber.new
+      @subscription = ActiveSupport::Notifications.subscribe('sql.active_record', @subscriber)
+      @connection = ActiveRecord::Base.connection
+    end
+
+    def teardown
+      ActiveSupport::Notifications.unsubscribe(@subscription)
+      super
+    end
+
+    def test_encoding
+      assert_not_nil @connection.encoding
+    end
+
+    def test_collation
+      assert_not_nil @connection.collation
+    end
+
+    def test_ctype
+      assert_not_nil @connection.ctype
+    end
+
+    def test_default_client_min_messages
+      assert_equal "warning", @connection.client_min_messages
+    end
+
+    # Ensure, we can set connection params using the example of Generic
+    # Query Optimizer (geqo). It is 'on' per default.
+    def test_connection_options
+      params = ActiveRecord::Base.connection_config.dup
+      params[:options] = "-c geqo=off"
+      NonExistentTable.establish_connection(params)
+
+      # Verify the connection param has been applied.
+      expect = NonExistentTable.connection.query('show geqo').first.first
+      assert_equal 'off', expect
+    end
+
+    def test_reset
+      @connection.query('ROLLBACK')
+      @connection.query('SET geqo TO off')
+
+      # Verify the setting has been applied.
+      expect = @connection.query('show geqo').first.first
+      assert_equal 'off', expect
+
+      @connection.reset!
+
+      # Verify the setting has been cleared.
+      expect = @connection.query('show geqo').first.first
+      assert_equal 'on', expect
+    end
+
+    def test_reset_with_transaction
+      @connection.query('ROLLBACK')
+      @connection.query('SET geqo TO off')
+
+      # Verify the setting has been applied.
+      expect = @connection.query('show geqo').first.first
+      assert_equal 'off', expect
+
+      @connection.query('BEGIN')
+      @connection.reset!
+
+      # Verify the setting has been cleared.
+      expect = @connection.query('show geqo').first.first
+      assert_equal 'on', expect
+    end
+
+    def test_tables_logs_name
+      @connection.tables('hello')
+      assert_equal 'SCHEMA', @subscriber.logged[0][1]
+    end
+
+    def test_indexes_logs_name
+      @connection.indexes('items', 'hello')
+      assert_equal 'SCHEMA', @subscriber.logged[0][1]
+    end
+
+    def test_table_exists_logs_name
+      @connection.table_exists?('items')
+      assert_equal 'SCHEMA', @subscriber.logged[0][1]
+    end
+
+    def test_table_alias_length_logs_name
+      @connection.instance_variable_set("@table_alias_length", nil)
+      @connection.table_alias_length
+      assert_equal 'SCHEMA', @subscriber.logged[0][1]
+    end
+
+    def test_current_database_logs_name
+      @connection.current_database
+      assert_equal 'SCHEMA', @subscriber.logged[0][1]
+    end
+
+    def test_encoding_logs_name
+      @connection.encoding
+      assert_equal 'SCHEMA', @subscriber.logged[0][1]
+    end
+
+    def test_schema_names_logs_name
+      @connection.schema_names
+      assert_equal 'SCHEMA', @subscriber.logged[0][1]
+    end
+
+    def test_statement_key_is_logged
+      bindval = 1
+      @connection.exec_query('SELECT $1::integer', 'SQL', [[nil, bindval]])
+      name = @subscriber.payloads.last[:statement_name]
+      assert name
+      res = @connection.exec_query("EXPLAIN (FORMAT JSON) EXECUTE #{name}(#{bindval})")
+      plan = res.column_types['QUERY PLAN'].type_cast_from_database res.rows.first.first
+      assert_operator plan.length, :>, 0
+    end
+
+    # Must have PostgreSQL >= 9.2, or with_manual_interventions set to
+    # true for this test to run.
+    #
+    # When prompted, restart the PostgreSQL server with the
+    # "-m fast" option or kill the individual connection assuming
+    # you know the incantation to do that.
+    # To restart PostgreSQL 9.1 on OS X, installed via MacPorts, ...
+    # sudo su postgres -c "pg_ctl restart -D /opt/local/var/db/postgresql91/defaultdb/ -m fast"
+    def test_reconnection_after_actual_disconnection_with_verify
+      original_connection_pid = @connection.query('select pg_backend_pid()')
+
+      # Sanity check.
+      assert @connection.active?
+
+      if @connection.send(:postgresql_version) >= 90200
+        secondary_connection = ActiveRecord::Base.connection_pool.checkout
+        secondary_connection.query("select pg_terminate_backend(#{original_connection_pid.first.first})")
+        ActiveRecord::Base.connection_pool.checkin(secondary_connection)
+      elsif ARTest.config['with_manual_interventions']
+        puts 'Kill the connection now (e.g. by restarting the PostgreSQL ' +
+          'server with the "-m fast" option) and then press enter.'
+        $stdin.gets
+      else
+        # We're not capable of terminating the backend ourselves, and
+        # we're not allowed to seek assistance; bail out without
+        # actually testing anything.
+        return
+      end
+
+      @connection.verify!
+
+      assert @connection.active?
+
+      # If we get no exception here, then either we re-connected successfully, or
+      # we never actually got disconnected.
+      new_connection_pid = @connection.query('select pg_backend_pid()')
+
+      assert_not_equal original_connection_pid, new_connection_pid,
+        "umm -- looks like you didn't break the connection, because we're still " +
+        "successfully querying with the same connection pid."
+
+      # Repair all fixture connections so other tests won't break.
+      @fixture_connections.each do |c|
+        c.verify!
+      end
+    end
+
+    def test_set_session_variable_true
+      run_without_connection do |orig_connection|
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:debug_print_plan => true}}))
+        set_true = ActiveRecord::Base.connection.exec_query "SHOW DEBUG_PRINT_PLAN"
+        assert_equal set_true.rows, [["on"]]
+      end
+    end
+
+    def test_set_session_variable_false
+      run_without_connection do |orig_connection|
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:debug_print_plan => false}}))
+        set_false = ActiveRecord::Base.connection.exec_query "SHOW DEBUG_PRINT_PLAN"
+        assert_equal set_false.rows, [["off"]]
+      end
+    end
+
+    def test_set_session_variable_nil
+      run_without_connection do |orig_connection|
+        # This should be a no-op that does not raise an error
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:debug_print_plan => nil}}))
+      end
+    end
+
+    def test_set_session_variable_default
+      run_without_connection do |orig_connection|
+        # This should execute a query that does not raise an error
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:debug_print_plan => :default}}))
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/datatype_test.rb b/activerecord/test/cases/adapters/postgresql/datatype_test.rb
new file mode 100644
index 0000000000..a0a34e4b87
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/datatype_test.rb
@@ -0,0 +1,119 @@
+require "cases/helper"
+require 'support/ddl_helper'
+
+
+class PostgresqlNumber < ActiveRecord::Base
+end
+
+class PostgresqlTime < ActiveRecord::Base
+end
+
+class PostgresqlOid < ActiveRecord::Base
+end
+
+class PostgresqlLtree < ActiveRecord::Base
+end
+
+class PostgresqlDataTypeTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    @connection.execute("INSERT INTO postgresql_numbers (id, single, double) VALUES (1, 123.456, 123456.789)")
+    @connection.execute("INSERT INTO postgresql_numbers (id, single, double) VALUES (2, '-Infinity', 'Infinity')")
+    @connection.execute("INSERT INTO postgresql_numbers (id, single, double) VALUES (3, 123.456, 'NaN')")
+    @first_number = PostgresqlNumber.find(1)
+    @second_number = PostgresqlNumber.find(2)
+    @third_number = PostgresqlNumber.find(3)
+
+    @connection.execute("INSERT INTO postgresql_times (id, time_interval, scaled_time_interval) VALUES (1, '1 year 2 days ago', '3 weeks ago')")
+    @first_time = PostgresqlTime.find(1)
+
+    @connection.execute("INSERT INTO postgresql_oids (id, obj_id) VALUES (1, 1234)")
+    @first_oid = PostgresqlOid.find(1)
+  end
+
+  teardown do
+    [PostgresqlNumber, PostgresqlTime, PostgresqlOid].each(&:delete_all)
+  end
+
+  def test_data_type_of_number_types
+    assert_equal :float, @first_number.column_for_attribute(:single).type
+    assert_equal :float, @first_number.column_for_attribute(:double).type
+  end
+
+  def test_data_type_of_time_types
+    assert_equal :string, @first_time.column_for_attribute(:time_interval).type
+    assert_equal :string, @first_time.column_for_attribute(:scaled_time_interval).type
+  end
+
+  def test_data_type_of_oid_types
+    assert_equal :integer, @first_oid.column_for_attribute(:obj_id).type
+  end
+
+  def test_number_values
+    assert_equal 123.456, @first_number.single
+    assert_equal 123456.789, @first_number.double
+    assert_equal(-::Float::INFINITY, @second_number.single)
+    assert_equal ::Float::INFINITY, @second_number.double
+    assert_same ::Float::NAN, @third_number.double
+  end
+
+  def test_time_values
+    assert_equal '-1 years -2 days', @first_time.time_interval
+    assert_equal '-21 days', @first_time.scaled_time_interval
+  end
+
+  def test_oid_values
+    assert_equal 1234, @first_oid.obj_id
+  end
+
+  def test_update_number
+    new_single = 789.012
+    new_double = 789012.345
+    @first_number.single = new_single
+    @first_number.double = new_double
+    assert @first_number.save
+    assert @first_number.reload
+    assert_equal new_single, @first_number.single
+    assert_equal new_double, @first_number.double
+  end
+
+  def test_update_time
+    @first_time.time_interval = '2 years 3 minutes'
+    assert @first_time.save
+    assert @first_time.reload
+    assert_equal '2 years 00:03:00', @first_time.time_interval
+  end
+
+  def test_update_oid
+    new_value = 567890
+    @first_oid.obj_id = new_value
+    assert @first_oid.save
+    assert @first_oid.reload
+    assert_equal new_value, @first_oid.obj_id
+  end
+end
+
+class PostgresqlInternalDataTypeTest < ActiveRecord::TestCase
+  include DdlHelper
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def test_name_column_type
+    with_example_table @connection, 'ex', 'data name' do
+      column = @connection.columns('ex').find { |col| col.name == 'data' }
+      assert_equal :string, column.type
+    end
+  end
+
+  def test_char_column_type
+    with_example_table @connection, 'ex', 'data "char"' do
+      column = @connection.columns('ex').find { |col| col.name == 'data' }
+      assert_equal :string, column.type
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/domain_test.rb b/activerecord/test/cases/adapters/postgresql/domain_test.rb
new file mode 100644
index 0000000000..1500adb42d
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/domain_test.rb
@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+require "cases/helper"
+require 'support/connection_helper'
+
+class PostgresqlDomainTest < ActiveRecord::TestCase
+  include ConnectionHelper
+
+  class PostgresqlDomain < ActiveRecord::Base
+    self.table_name = "postgresql_domains"
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.transaction do
+      @connection.execute "CREATE DOMAIN custom_money as numeric(8,2)"
+      @connection.create_table('postgresql_domains') do |t|
+        t.column :price, :custom_money
+      end
+    end
+  end
+
+  teardown do
+    @connection.execute 'DROP TABLE IF EXISTS postgresql_domains'
+    @connection.execute 'DROP DOMAIN IF EXISTS custom_money'
+    reset_connection
+  end
+
+  def test_column
+    column = PostgresqlDomain.columns_hash["price"]
+    assert_equal :decimal, column.type
+    assert_equal "custom_money", column.sql_type
+    assert column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_domain_acts_like_basetype
+    PostgresqlDomain.create price: ""
+    record = PostgresqlDomain.first
+    assert_nil record.price
+
+    record.price = "34.15"
+    record.save!
+
+    assert_equal BigDecimal.new("34.15"), record.reload.price
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/enum_test.rb b/activerecord/test/cases/adapters/postgresql/enum_test.rb
new file mode 100644
index 0000000000..d99c4a292e
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/enum_test.rb
@@ -0,0 +1,85 @@
+# -*- coding: utf-8 -*-
+require "cases/helper"
+require 'support/connection_helper'
+require 'active_record/base'
+require 'active_record/connection_adapters/postgresql_adapter'
+
+class PostgresqlEnumTest < ActiveRecord::TestCase
+  include ConnectionHelper
+
+  class PostgresqlEnum < ActiveRecord::Base
+    self.table_name = "postgresql_enums"
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.transaction do
+      @connection.execute <<-SQL
+        CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy');
+      SQL
+      @connection.create_table('postgresql_enums') do |t|
+        t.column :current_mood, :mood
+      end
+    end
+  end
+
+  teardown do
+    @connection.execute 'DROP TABLE IF EXISTS postgresql_enums'
+    @connection.execute 'DROP TYPE IF EXISTS mood'
+    reset_connection
+  end
+
+  def test_column
+    column = PostgresqlEnum.columns_hash["current_mood"]
+    assert_equal :enum, column.type
+    assert_equal "mood", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_enum_defaults
+    @connection.add_column 'postgresql_enums', 'good_mood', :mood, default: 'happy'
+    PostgresqlEnum.reset_column_information
+
+    assert_equal "happy", PostgresqlEnum.column_defaults['good_mood']
+    assert_equal "happy", PostgresqlEnum.new.good_mood
+  ensure
+    PostgresqlEnum.reset_column_information
+  end
+
+  def test_enum_mapping
+    @connection.execute "INSERT INTO postgresql_enums VALUES (1, 'sad');"
+    enum = PostgresqlEnum.first
+    assert_equal "sad", enum.current_mood
+
+    enum.current_mood = "happy"
+    enum.save!
+
+    assert_equal "happy", enum.reload.current_mood
+  end
+
+  def test_invalid_enum_update
+    @connection.execute "INSERT INTO postgresql_enums VALUES (1, 'sad');"
+    enum = PostgresqlEnum.first
+    enum.current_mood = "angry"
+
+    assert_raise ActiveRecord::StatementInvalid do
+      enum.save
+    end
+  end
+
+  def test_no_oid_warning
+    @connection.execute "INSERT INTO postgresql_enums VALUES (1, 'sad');"
+    stderr_output = capture(:stderr) { PostgresqlEnum.first }
+
+    assert stderr_output.blank?
+  end
+
+  def test_enum_type_cast
+    enum = PostgresqlEnum.new
+    enum.current_mood = :happy
+
+    assert_equal "happy", enum.current_mood
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/explain_test.rb b/activerecord/test/cases/adapters/postgresql/explain_test.rb
new file mode 100644
index 0000000000..416f84cb38
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/explain_test.rb
@@ -0,0 +1,28 @@
+require "cases/helper"
+require 'models/developer'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLAdapter
+      class ExplainTest < ActiveRecord::TestCase
+        fixtures :developers
+
+        def test_explain_for_one_query
+          explain = Developer.where(:id => 1).explain
+          assert_match %(EXPLAIN for: SELECT "developers".* FROM "developers" WHERE "developers"."id" = $1), explain
+          assert_match %(QUERY PLAN), explain
+          assert_match %(Index Scan using developers_pkey on developers), explain
+        end
+
+        def test_explain_with_eager_loading
+          explain = Developer.where(:id => 1).includes(:audit_logs).explain
+          assert_match %(QUERY PLAN), explain
+          assert_match %(EXPLAIN for: SELECT "developers".* FROM "developers" WHERE "developers"."id" = $1), explain
+          assert_match %(Index Scan using developers_pkey on developers), explain
+          assert_match %(EXPLAIN for: SELECT "audit_logs".* FROM "audit_logs" WHERE "audit_logs"."developer_id" IN (1)), explain
+          assert_match %(Seq Scan on audit_logs), explain
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb b/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb
new file mode 100644
index 0000000000..7b99fcdda0
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb
@@ -0,0 +1,63 @@
+require "cases/helper"
+
+class PostgresqlExtensionMigrationTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  class EnableHstore < ActiveRecord::Migration
+    def change
+      enable_extension "hstore"
+    end
+  end
+
+  class DisableHstore < ActiveRecord::Migration
+    def change
+      disable_extension "hstore"
+    end
+  end
+
+  def setup
+    super
+
+    @connection = ActiveRecord::Base.connection
+
+    unless @connection.supports_extensions?
+      return skip("no extension support")
+    end
+
+    @old_schema_migration_tabel_name = ActiveRecord::SchemaMigration.table_name
+    @old_tabel_name_prefix = ActiveRecord::Base.table_name_prefix
+    @old_tabel_name_suffix = ActiveRecord::Base.table_name_suffix
+
+    ActiveRecord::Base.table_name_prefix = "p_"
+    ActiveRecord::Base.table_name_suffix = "_s"
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    ActiveRecord::SchemaMigration.table_name = "p_schema_migrations_s"
+    ActiveRecord::Migration.verbose = false
+  end
+
+  def teardown
+    ActiveRecord::Base.table_name_prefix = @old_tabel_name_prefix
+    ActiveRecord::Base.table_name_suffix = @old_tabel_name_suffix
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    ActiveRecord::Migration.verbose = true
+    ActiveRecord::SchemaMigration.table_name = @old_schema_migration_tabel_name
+
+    super
+  end
+
+  def test_enable_extension_migration_ignores_prefix_and_suffix
+    @connection.disable_extension("hstore")
+
+    migrations = [EnableHstore.new(nil, 1)]
+    ActiveRecord::Migrator.new(:up, migrations).migrate
+    assert @connection.extension_enabled?("hstore"), "extension hstore should be enabled"
+  end
+
+  def test_disable_extension_migration_ignores_prefix_and_suffix
+    @connection.enable_extension("hstore")
+
+    migrations = [DisableHstore.new(nil, 1)]
+    ActiveRecord::Migrator.new(:up, migrations).migrate
+    assert_not @connection.extension_enabled?("hstore"), "extension hstore should not be enabled"
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/full_text_test.rb b/activerecord/test/cases/adapters/postgresql/full_text_test.rb
new file mode 100644
index 0000000000..9dadb177ca
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/full_text_test.rb
@@ -0,0 +1,26 @@
+# encoding: utf-8
+require "cases/helper"
+
+class PostgresqlFullTextTest < ActiveRecord::TestCase
+  class PostgresqlTsvector < ActiveRecord::Base; end
+
+  def test_tsvector_column
+    column = PostgresqlTsvector.columns_hash["text_vector"]
+    assert_equal :tsvector, column.type
+    assert_equal "tsvector", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_update_tsvector
+    PostgresqlTsvector.create text_vector: "'text' 'vector'"
+    tsvector = PostgresqlTsvector.first
+    assert_equal "'text' 'vector'", tsvector.text_vector
+
+    tsvector.text_vector = "'new' 'text' 'vector'"
+    tsvector.save!
+    assert tsvector.reload
+    assert_equal "'new' 'text' 'vector'", tsvector.text_vector
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/geometric_test.rb b/activerecord/test/cases/adapters/postgresql/geometric_test.rb
new file mode 100644
index 0000000000..6c0adbbeaa
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/geometric_test.rb
@@ -0,0 +1,72 @@
+# -*- coding: utf-8 -*-
+require "cases/helper"
+require 'support/connection_helper'
+require 'support/schema_dumping_helper'
+
+class PostgresqlPointTest < ActiveRecord::TestCase
+  include ConnectionHelper
+  include SchemaDumpingHelper
+
+  class PostgresqlPoint < ActiveRecord::Base; end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.transaction do
+      @connection.create_table('postgresql_points') do |t|
+        t.point :x
+        t.point :y, default: [12.2, 13.3]
+        t.point :z, default: "(14.4,15.5)"
+      end
+    end
+  end
+
+  teardown do
+    @connection.execute 'DROP TABLE IF EXISTS postgresql_points'
+  end
+
+  def test_column
+    column = PostgresqlPoint.columns_hash["x"]
+    assert_equal :point, column.type
+    assert_equal "point", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_default
+    assert_equal [12.2, 13.3], PostgresqlPoint.column_defaults['y']
+    assert_equal [12.2, 13.3], PostgresqlPoint.new.y
+
+    assert_equal [14.4, 15.5], PostgresqlPoint.column_defaults['z']
+    assert_equal [14.4, 15.5], PostgresqlPoint.new.z
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("postgresql_points")
+    assert_match %r{t\.point\s+"x"$}, output
+    assert_match %r{t\.point\s+"y",\s+default: \[12\.2, 13\.3\]$}, output
+    assert_match %r{t\.point\s+"z",\s+default: \[14\.4, 15\.5\]$}, output
+  end
+
+  def test_roundtrip
+    PostgresqlPoint.create! x: [10, 25.2]
+    record = PostgresqlPoint.first
+    assert_equal [10, 25.2], record.x
+
+    record.x = [1.1, 2.2]
+    record.save!
+    assert record.reload
+    assert_equal [1.1, 2.2], record.x
+  end
+
+  def test_mutation
+    p = PostgresqlPoint.create! x: [10, 20]
+
+    p.x[1] = 25
+    p.save!
+    p.reload
+
+    assert_equal [10.0, 25.0], p.x
+    assert_not p.changed?
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/hstore_test.rb b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
new file mode 100644
index 0000000000..1296eb72c0
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
@@ -0,0 +1,349 @@
+# encoding: utf-8
+
+require "cases/helper"
+require 'active_record/base'
+require 'active_record/connection_adapters/postgresql_adapter'
+
+class PostgresqlHstoreTest < ActiveRecord::TestCase
+  class Hstore < ActiveRecord::Base
+    self.table_name = 'hstores'
+
+    store_accessor :settings, :language, :timezone
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    unless @connection.extension_enabled?('hstore')
+      @connection.enable_extension 'hstore'
+      @connection.commit_db_transaction
+    end
+
+    @connection.reconnect!
+
+    @connection.transaction do
+      @connection.create_table('hstores') do |t|
+        t.hstore 'tags', :default => ''
+        t.hstore 'payload', array: true
+        t.hstore 'settings'
+      end
+    end
+    @column = Hstore.columns_hash['tags']
+  end
+
+  teardown do
+    @connection.execute 'drop table if exists hstores'
+  end
+
+  if ActiveRecord::Base.connection.supports_extensions?
+    def test_hstore_included_in_extensions
+      assert @connection.respond_to?(:extensions), "connection should have a list of extensions"
+      assert @connection.extensions.include?('hstore'), "extension list should include hstore"
+    end
+
+    def test_disable_enable_hstore
+      assert @connection.extension_enabled?('hstore')
+      @connection.disable_extension 'hstore'
+      assert_not @connection.extension_enabled?('hstore')
+      @connection.enable_extension 'hstore'
+      assert @connection.extension_enabled?('hstore')
+    ensure
+      # Restore column(s) dropped by `drop extension hstore cascade;`
+      load_schema
+    end
+
+    def test_column
+      assert_equal :hstore, @column.type
+      assert_equal "hstore", @column.sql_type
+      assert_not @column.number?
+      assert_not @column.binary?
+      assert_not @column.array
+    end
+
+    def test_default
+      @connection.add_column 'hstores', 'permissions', :hstore, default: '"users"=>"read", "articles"=>"write"'
+      Hstore.reset_column_information
+
+      assert_equal({"users"=>"read", "articles"=>"write"}, Hstore.column_defaults['permissions'])
+      assert_equal({"users"=>"read", "articles"=>"write"}, Hstore.new.permissions)
+    ensure
+      Hstore.reset_column_information
+    end
+
+    def test_change_table_supports_hstore
+      @connection.transaction do
+        @connection.change_table('hstores') do |t|
+          t.hstore 'users', default: ''
+        end
+        Hstore.reset_column_information
+        column = Hstore.columns_hash['users']
+        assert_equal :hstore, column.type
+
+        raise ActiveRecord::Rollback # reset the schema change
+      end
+    ensure
+      Hstore.reset_column_information
+    end
+
+    def test_hstore_migration
+      hstore_migration = Class.new(ActiveRecord::Migration) do
+        def change
+          change_table("hstores") do |t|
+            t.hstore :keys
+          end
+        end
+      end
+
+      hstore_migration.new.suppress_messages do
+        hstore_migration.migrate(:up)
+        assert_includes @connection.columns(:hstores).map(&:name), "keys"
+        hstore_migration.migrate(:down)
+        assert_not_includes @connection.columns(:hstores).map(&:name), "keys"
+      end
+    end
+
+    def test_cast_value_on_write
+      x = Hstore.new tags: {"bool" => true, "number" => 5}
+      assert_equal({"bool" => true, "number" => 5}, x.tags_before_type_cast)
+      assert_equal({"bool" => "true", "number" => "5"}, x.tags)
+      x.save
+      assert_equal({"bool" => "true", "number" => "5"}, x.reload.tags)
+    end
+
+    def test_type_cast_hstore
+      assert_equal({'1' => '2'}, @column.type_cast_from_database("\"1\"=>\"2\""))
+      assert_equal({}, @column.type_cast_from_database(""))
+      assert_equal({'key'=>nil}, @column.type_cast_from_database('key => NULL'))
+      assert_equal({'c'=>'}','"a"'=>'b "a b'}, @column.type_cast_from_database(%q(c=>"}", "\"a\""=>"b \"a b")))
+    end
+
+    def test_with_store_accessors
+      x = Hstore.new(language: "fr", timezone: "GMT")
+      assert_equal "fr", x.language
+      assert_equal "GMT", x.timezone
+
+      x.save!
+      x = Hstore.first
+      assert_equal "fr", x.language
+      assert_equal "GMT", x.timezone
+
+      x.language = "de"
+      x.save!
+
+      x = Hstore.first
+      assert_equal "de", x.language
+      assert_equal "GMT", x.timezone
+    end
+
+    def test_duplication_with_store_accessors
+      x = Hstore.new(language: "fr", timezone: "GMT")
+      assert_equal "fr", x.language
+      assert_equal "GMT", x.timezone
+
+      y = x.dup
+      assert_equal "fr", y.language
+      assert_equal "GMT", y.timezone
+    end
+
+    def test_yaml_round_trip_with_store_accessors
+      x = Hstore.new(language: "fr", timezone: "GMT")
+      assert_equal "fr", x.language
+      assert_equal "GMT", x.timezone
+
+      y = YAML.load(YAML.dump(x))
+      assert_equal "fr", y.language
+      assert_equal "GMT", y.timezone
+    end
+
+    def test_changes_in_place
+      hstore = Hstore.create!(settings: { 'one' => 'two' })
+      hstore.settings['three'] = 'four'
+      hstore.save!
+      hstore.reload
+
+      assert_equal 'four', hstore.settings['three']
+      assert_not hstore.changed?
+    end
+
+    def test_gen1
+      assert_equal(%q(" "=>""), @column.cast_type.type_cast_for_database({' '=>''}))
+    end
+
+    def test_gen2
+      assert_equal(%q(","=>""), @column.cast_type.type_cast_for_database({','=>''}))
+    end
+
+    def test_gen3
+      assert_equal(%q("="=>""), @column.cast_type.type_cast_for_database({'='=>''}))
+    end
+
+    def test_gen4
+      assert_equal(%q(">"=>""), @column.cast_type.type_cast_for_database({'>'=>''}))
+    end
+
+    def test_parse1
+      assert_equal({'a'=>nil,'b'=>nil,'c'=>'NuLl','null'=>'c'}, @column.type_cast_from_database('a=>null,b=>NuLl,c=>"NuLl",null=>c'))
+    end
+
+    def test_parse2
+      assert_equal({" " => " "},  @column.type_cast_from_database("\\ =>\\ "))
+    end
+
+    def test_parse3
+      assert_equal({"=" => ">"},  @column.type_cast_from_database("==>>"))
+    end
+
+    def test_parse4
+      assert_equal({"=a"=>"q=w"},   @column.type_cast_from_database('\=a=>q=w'))
+    end
+
+    def test_parse5
+      assert_equal({"=a"=>"q=w"},   @column.type_cast_from_database('"=a"=>q\=w'))
+    end
+
+    def test_parse6
+      assert_equal({"\"a"=>"q>w"},  @column.type_cast_from_database('"\"a"=>q>w'))
+    end
+
+    def test_parse7
+      assert_equal({"\"a"=>"q\"w"}, @column.type_cast_from_database('\"a=>q"w'))
+    end
+
+    def test_rewrite
+      @connection.execute "insert into hstores (tags) VALUES ('1=>2')"
+      x = Hstore.first
+      x.tags = { '"a\'' => 'b' }
+      assert x.save!
+    end
+
+    def test_select
+      @connection.execute "insert into hstores (tags) VALUES ('1=>2')"
+      x = Hstore.first
+      assert_equal({'1' => '2'}, x.tags)
+    end
+
+    def test_array_cycle
+      assert_array_cycle([{"AA" => "BB", "CC" => "DD"}, {"AA" => nil}])
+    end
+
+    def test_array_strings_with_quotes
+      assert_array_cycle([{'this has' => 'some "s that need to be escaped"'}])
+    end
+
+    def test_array_strings_with_commas
+      assert_array_cycle([{'this,has' => 'many,values'}])
+    end
+
+    def test_array_strings_with_array_delimiters
+      assert_array_cycle(['{' => '}'])
+    end
+
+    def test_array_strings_with_null_strings
+      assert_array_cycle([{'NULL' => 'NULL'}])
+    end
+
+    def test_contains_nils
+      assert_array_cycle([{'NULL' => nil}])
+    end
+
+    def test_select_multikey
+      @connection.execute "insert into hstores (tags) VALUES ('1=>2,2=>3')"
+      x = Hstore.first
+      assert_equal({'1' => '2', '2' => '3'}, x.tags)
+    end
+
+    def test_create
+      assert_cycle('a' => 'b', '1' => '2')
+    end
+
+    def test_nil
+      assert_cycle('a' => nil)
+    end
+
+    def test_quotes
+      assert_cycle('a' => 'b"ar', '1"foo' => '2')
+    end
+
+    def test_whitespace
+      assert_cycle('a b' => 'b ar', '1"foo' => '2')
+    end
+
+    def test_backslash
+      assert_cycle('a\\b' => 'b\\ar', '1"foo' => '2')
+    end
+
+    def test_comma
+      assert_cycle('a, b' => 'bar', '1"foo' => '2')
+    end
+
+    def test_arrow
+      assert_cycle('a=>b' => 'bar', '1"foo' => '2')
+    end
+
+    def test_quoting_special_characters
+      assert_cycle('ca' => 'cà', 'ac' => 'àc')
+    end
+
+    def test_multiline
+      assert_cycle("a\nb" => "c\nd")
+    end
+
+    class TagCollection
+      def initialize(hash); @hash = hash end
+      def to_hash; @hash end
+      def self.load(hash); new(hash) end
+      def self.dump(object); object.to_hash end
+    end
+
+    class HstoreWithSerialize < Hstore
+      serialize :tags, TagCollection
+    end
+
+    def test_hstore_with_serialized_attributes
+      HstoreWithSerialize.create! tags: TagCollection.new({"one" => "two"})
+      record = HstoreWithSerialize.first
+      assert_instance_of TagCollection, record.tags
+      assert_equal({"one" => "two"}, record.tags.to_hash)
+      record.tags = TagCollection.new("three" => "four")
+      record.save!
+      assert_equal({"three" => "four"}, HstoreWithSerialize.first.tags.to_hash)
+    end
+
+    def test_clone_hstore_with_serialized_attributes
+      HstoreWithSerialize.create! tags: TagCollection.new({"one" => "two"})
+      record = HstoreWithSerialize.first
+      dupe = record.dup
+      assert_equal({"one" => "two"}, dupe.tags.to_hash)
+    end
+  end
+
+  private
+
+    def assert_array_cycle(array)
+      # test creation
+      x = Hstore.create!(payload: array)
+      x.reload
+      assert_equal(array, x.payload)
+
+      # test updating
+      x = Hstore.create!(payload: [])
+      x.payload = array
+      x.save!
+      x.reload
+      assert_equal(array, x.payload)
+    end
+
+    def assert_cycle(hash)
+      # test creation
+      x = Hstore.create!(:tags => hash)
+      x.reload
+      assert_equal(hash, x.tags)
+
+      # test updating
+      x = Hstore.create!(:tags => {})
+      x.tags = hash
+      x.save!
+      x.reload
+      assert_equal(hash, x.tags)
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/infinity_test.rb b/activerecord/test/cases/adapters/postgresql/infinity_test.rb
new file mode 100644
index 0000000000..22e8873333
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/infinity_test.rb
@@ -0,0 +1,44 @@
+require "cases/helper"
+
+class PostgresqlInfinityTest < ActiveRecord::TestCase
+  class PostgresqlInfinity < ActiveRecord::Base
+  end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table(:postgresql_infinities) do |t|
+      t.float :float
+      t.datetime :datetime
+    end
+  end
+
+  teardown do
+    @connection.execute("DROP TABLE IF EXISTS postgresql_infinities")
+  end
+
+  test "type casting infinity on a float column" do
+    record = PostgresqlInfinity.create!(float: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.float
+  end
+
+  test "update_all with infinity on a float column" do
+    record = PostgresqlInfinity.create!
+    PostgresqlInfinity.update_all(float: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.float
+  end
+
+  test "type casting infinity on a datetime column" do
+    record = PostgresqlInfinity.create!(datetime: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.datetime
+  end
+
+  test "update_all with infinity on a datetime column" do
+    record = PostgresqlInfinity.create!
+    PostgresqlInfinity.update_all(datetime: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.datetime
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/json_test.rb b/activerecord/test/cases/adapters/postgresql/json_test.rb
new file mode 100644
index 0000000000..86ba849445
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/json_test.rb
@@ -0,0 +1,193 @@
+# encoding: utf-8
+
+require "cases/helper"
+require 'active_record/base'
+require 'active_record/connection_adapters/postgresql_adapter'
+
+module PostgresqlJSONSharedTestCases
+  class JsonDataType < ActiveRecord::Base
+    self.table_name = 'json_data_type'
+
+    store_accessor :settings, :resolution
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    begin
+      @connection.transaction do
+        @connection.create_table('json_data_type') do |t|
+          t.public_send column_type, 'payload', default: {} # t.json 'payload', default: {}
+          t.public_send column_type, 'settings'             # t.json 'settings'
+        end
+      end
+    rescue ActiveRecord::StatementInvalid
+      skip "do not test on PG without json"
+    end
+    @column = JsonDataType.columns_hash['payload']
+  end
+
+  def teardown
+    @connection.execute 'drop table if exists json_data_type'
+  end
+
+  def test_column
+    column = JsonDataType.columns_hash["payload"]
+    assert_equal column_type, column.type
+    assert_equal column_type.to_s, column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_default
+    @connection.add_column 'json_data_type', 'permissions', column_type, default: '{"users": "read", "posts": ["read", "write"]}'
+    JsonDataType.reset_column_information
+
+    assert_equal({"users"=>"read", "posts"=>["read", "write"]}, JsonDataType.column_defaults['permissions'])
+    assert_equal({"users"=>"read", "posts"=>["read", "write"]}, JsonDataType.new.permissions)
+  ensure
+    JsonDataType.reset_column_information
+  end
+
+  def test_change_table_supports_json
+    @connection.transaction do
+      @connection.change_table('json_data_type') do |t|
+        t.public_send column_type, 'users', default: '{}' # t.json 'users', default: '{}'
+      end
+      JsonDataType.reset_column_information
+      column = JsonDataType.columns_hash['users']
+      assert_equal column_type, column.type
+
+      raise ActiveRecord::Rollback # reset the schema change
+    end
+  ensure
+    JsonDataType.reset_column_information
+  end
+
+  def test_cast_value_on_write
+    x = JsonDataType.new payload: {"string" => "foo", :symbol => :bar}
+    assert_equal({"string" => "foo", :symbol => :bar}, x.payload_before_type_cast)
+    assert_equal({"string" => "foo", "symbol" => "bar"}, x.payload)
+    x.save
+    assert_equal({"string" => "foo", "symbol" => "bar"}, x.reload.payload)
+  end
+
+  def test_type_cast_json
+    column = JsonDataType.columns_hash["payload"]
+
+    data = "{\"a_key\":\"a_value\"}"
+    hash = column.type_cast_from_database(data)
+    assert_equal({'a_key' => 'a_value'}, hash)
+    assert_equal({'a_key' => 'a_value'}, column.type_cast_from_database(data))
+
+    assert_equal({}, column.type_cast_from_database("{}"))
+    assert_equal({'key'=>nil}, column.type_cast_from_database('{"key": null}'))
+    assert_equal({'c'=>'}','"a"'=>'b "a b'}, column.type_cast_from_database(%q({"c":"}", "\"a\"":"b \"a b"})))
+  end
+
+  def test_rewrite
+    @connection.execute "insert into json_data_type (payload) VALUES ('{\"k\":\"v\"}')"
+    x = JsonDataType.first
+    x.payload = { '"a\'' => 'b' }
+    assert x.save!
+  end
+
+  def test_select
+    @connection.execute "insert into json_data_type (payload) VALUES ('{\"k\":\"v\"}')"
+    x = JsonDataType.first
+    assert_equal({'k' => 'v'}, x.payload)
+  end
+
+  def test_select_multikey
+    @connection.execute %q|insert into json_data_type (payload) VALUES ('{"k1":"v1", "k2":"v2", "k3":[1,2,3]}')|
+    x = JsonDataType.first
+    assert_equal({'k1' => 'v1', 'k2' => 'v2', 'k3' => [1,2,3]}, x.payload)
+  end
+
+  def test_null_json
+    @connection.execute %q|insert into json_data_type (payload) VALUES(null)|
+    x = JsonDataType.first
+    assert_equal(nil, x.payload)
+  end
+
+  def test_select_array_json_value
+    @connection.execute %q|insert into json_data_type (payload) VALUES ('["v0",{"k1":"v1"}]')|
+    x = JsonDataType.first
+    assert_equal(['v0', {'k1' => 'v1'}], x.payload)
+  end
+
+  def test_rewrite_array_json_value
+    @connection.execute %q|insert into json_data_type (payload) VALUES ('["v0",{"k1":"v1"}]')|
+    x = JsonDataType.first
+    x.payload = ['v1', {'k2' => 'v2'}, 'v3']
+    assert x.save!
+  end
+
+  def test_with_store_accessors
+    x = JsonDataType.new(resolution: "320×480")
+    assert_equal "320×480", x.resolution
+
+    x.save!
+    x = JsonDataType.first
+    assert_equal "320×480", x.resolution
+
+    x.resolution = "640×1136"
+    x.save!
+
+    x = JsonDataType.first
+    assert_equal "640×1136", x.resolution
+  end
+
+  def test_duplication_with_store_accessors
+    x = JsonDataType.new(resolution: "320×480")
+    assert_equal "320×480", x.resolution
+
+    y = x.dup
+    assert_equal "320×480", y.resolution
+  end
+
+  def test_yaml_round_trip_with_store_accessors
+    x = JsonDataType.new(resolution: "320×480")
+    assert_equal "320×480", x.resolution
+
+    y = YAML.load(YAML.dump(x))
+    assert_equal "320×480", y.resolution
+  end
+
+  def test_changes_in_place
+    json = JsonDataType.new
+    assert_not json.changed?
+
+    json.payload = { 'one' => 'two' }
+    assert json.changed?
+    assert json.payload_changed?
+
+    json.save!
+    assert_not json.changed?
+
+    json.payload['three'] = 'four'
+    assert json.payload_changed?
+
+    json.save!
+    json.reload
+
+    assert_equal({ 'one' => 'two', 'three' => 'four' }, json.payload)
+    assert_not json.changed?
+  end
+end
+
+class PostgresqlJSONTest < ActiveRecord::TestCase
+  include PostgresqlJSONSharedTestCases
+
+  def column_type
+    :json
+  end
+end
+
+class PostgresqlJSONBTest < ActiveRecord::TestCase
+  include PostgresqlJSONSharedTestCases
+
+  def column_type
+    :jsonb
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/ltree_test.rb b/activerecord/test/cases/adapters/postgresql/ltree_test.rb
new file mode 100644
index 0000000000..889e369bd6
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/ltree_test.rb
@@ -0,0 +1,48 @@
+# encoding: utf-8
+require "cases/helper"
+
+class PostgresqlLtreeTest < ActiveRecord::TestCase
+  class Ltree < ActiveRecord::Base
+    self.table_name = 'ltrees'
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    unless @connection.extension_enabled?('ltree')
+      @connection.enable_extension 'ltree'
+    end
+
+    @connection.transaction do
+      @connection.create_table('ltrees') do |t|
+        t.ltree 'path'
+      end
+    end
+  rescue ActiveRecord::StatementInvalid
+    skip "do not test on PG without ltree"
+  end
+
+  teardown do
+    @connection.execute 'drop table if exists ltrees'
+  end
+
+  def test_column
+    column = Ltree.columns_hash['path']
+    assert_equal :ltree, column.type
+    assert_equal "ltree", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_write
+    ltree = Ltree.new(path: '1.2.3.4')
+    assert ltree.save!
+  end
+
+  def test_select
+    @connection.execute "insert into ltrees (path) VALUES ('1.2.3')"
+    ltree = Ltree.first
+    assert_equal '1.2.3', ltree.path
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/money_test.rb b/activerecord/test/cases/adapters/postgresql/money_test.rb
new file mode 100644
index 0000000000..87183174f2
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/money_test.rb
@@ -0,0 +1,96 @@
+# encoding: utf-8
+require "cases/helper"
+require 'support/schema_dumping_helper'
+
+class PostgresqlMoneyTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+
+  class PostgresqlMoney < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.execute("set lc_monetary = 'C'")
+    @connection.create_table('postgresql_moneys') do |t|
+      t.column "wealth", "money"
+      t.column "depth", "money", default: "150.55"
+    end
+  end
+
+  teardown do
+    @connection.execute 'DROP TABLE IF EXISTS postgresql_moneys'
+  end
+
+  def test_column
+    column = PostgresqlMoney.columns_hash["wealth"]
+    assert_equal :money, column.type
+    assert_equal "money", column.sql_type
+    assert_equal 2, column.scale
+    assert column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_default
+    assert_equal BigDecimal.new("150.55"), PostgresqlMoney.column_defaults['depth']
+    assert_equal BigDecimal.new("150.55"), PostgresqlMoney.new.depth
+  end
+
+  def test_money_values
+    @connection.execute("INSERT INTO postgresql_moneys (id, wealth) VALUES (1, '567.89'::money)")
+    @connection.execute("INSERT INTO postgresql_moneys (id, wealth) VALUES (2, '-567.89'::money)")
+
+    first_money = PostgresqlMoney.find(1)
+    second_money = PostgresqlMoney.find(2)
+    assert_equal 567.89, first_money.wealth
+    assert_equal(-567.89, second_money.wealth)
+  end
+
+  def test_money_type_cast
+    column = PostgresqlMoney.columns_hash['wealth']
+    assert_equal(12345678.12, column.type_cast_from_user("$12,345,678.12"))
+    assert_equal(12345678.12, column.type_cast_from_user("$12.345.678,12"))
+    assert_equal(-1.15, column.type_cast_from_user("-$1.15"))
+    assert_equal(-2.25, column.type_cast_from_user("($2.25)"))
+  end
+
+  def test_schema_dumping
+    output = dump_table_schema("postgresql_moneys")
+    assert_match %r{t\.money\s+"wealth",\s+scale: 2$}, output
+    assert_match %r{t\.money\s+"depth",\s+scale: 2,\s+default: 150.55$}, output
+  end
+
+  def test_create_and_update_money
+    money = PostgresqlMoney.create(wealth: "987.65")
+    assert_equal 987.65, money.wealth
+
+    new_value = BigDecimal.new('123.45')
+    money.wealth = new_value
+    money.save!
+    money.reload
+    assert_equal new_value, money.wealth
+  end
+
+  def test_update_all_with_money_string
+    money = PostgresqlMoney.create!
+    PostgresqlMoney.update_all(wealth: "987.65")
+    money.reload
+
+    assert_equal 987.65, money.wealth
+  end
+
+  def test_update_all_with_money_big_decimal
+    money = PostgresqlMoney.create!
+    PostgresqlMoney.update_all(wealth: '123.45'.to_d)
+    money.reload
+
+    assert_equal 123.45, money.wealth
+  end
+
+  def test_update_all_with_money_numeric
+    money = PostgresqlMoney.create!
+    PostgresqlMoney.update_all(wealth: 123.45)
+    money.reload
+
+    assert_equal 123.45, money.wealth
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/network_test.rb b/activerecord/test/cases/adapters/postgresql/network_test.rb
new file mode 100644
index 0000000000..4f4c1103fa
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/network_test.rb
@@ -0,0 +1,71 @@
+# encoding: utf-8
+require "cases/helper"
+
+class PostgresqlNetworkTest < ActiveRecord::TestCase
+  class PostgresqlNetworkAddress < ActiveRecord::Base
+  end
+
+  def test_cidr_column
+    column = PostgresqlNetworkAddress.columns_hash["cidr_address"]
+    assert_equal :cidr, column.type
+    assert_equal "cidr", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_inet_column
+    column = PostgresqlNetworkAddress.columns_hash["inet_address"]
+    assert_equal :inet, column.type
+    assert_equal "inet", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_macaddr_column
+    column = PostgresqlNetworkAddress.columns_hash["mac_address"]
+    assert_equal :macaddr, column.type
+    assert_equal "macaddr", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_network_types
+    PostgresqlNetworkAddress.create(cidr_address: '192.168.0.0/24',
+                                    inet_address: '172.16.1.254/32',
+                                    mac_address: '01:23:45:67:89:0a')
+
+    address = PostgresqlNetworkAddress.first
+    assert_equal IPAddr.new('192.168.0.0/24'), address.cidr_address
+    assert_equal IPAddr.new('172.16.1.254'), address.inet_address
+    assert_equal '01:23:45:67:89:0a', address.mac_address
+
+    address.cidr_address = '10.1.2.3/32'
+    address.inet_address = '10.0.0.0/8'
+    address.mac_address = 'bc:de:f0:12:34:56'
+
+    address.save!
+    assert address.reload
+    assert_equal IPAddr.new('10.1.2.3/32'), address.cidr_address
+    assert_equal IPAddr.new('10.0.0.0/8'), address.inet_address
+    assert_equal 'bc:de:f0:12:34:56', address.mac_address
+  end
+
+  def test_invalid_network_address
+    invalid_address = PostgresqlNetworkAddress.new(cidr_address: 'invalid addr',
+                                                   inet_address: 'invalid addr')
+    assert_nil invalid_address.cidr_address
+    assert_nil invalid_address.inet_address
+    assert_equal 'invalid addr', invalid_address.cidr_address_before_type_cast
+    assert_equal 'invalid addr', invalid_address.inet_address_before_type_cast
+    assert invalid_address.save
+
+    invalid_address.reload
+    assert_nil invalid_address.cidr_address
+    assert_nil invalid_address.inet_address
+    assert_nil invalid_address.cidr_address_before_type_cast
+    assert_nil invalid_address.inet_address_before_type_cast
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb b/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
new file mode 100644
index 0000000000..cfff1f980b
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
@@ -0,0 +1,451 @@
+# encoding: utf-8
+require "cases/helper"
+require 'support/ddl_helper'
+require 'support/connection_helper'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLAdapterTest < ActiveRecord::TestCase
+      include DdlHelper
+      include ConnectionHelper
+
+      def setup
+        @connection = ActiveRecord::Base.connection
+      end
+
+      def test_bad_connection
+        assert_raise ActiveRecord::NoDatabaseError do
+          configuration = ActiveRecord::Base.configurations['arunit'].merge(database: 'should_not_exist-cinco-dog-db')
+          connection = ActiveRecord::Base.postgresql_connection(configuration)
+          connection.exec_query('SELECT 1')
+        end
+      end
+
+      def test_valid_column
+        with_example_table do
+          column = @connection.columns('ex').find { |col| col.name == 'id' }
+          assert @connection.valid_type?(column.type)
+        end
+      end
+
+      def test_invalid_column
+        assert_not @connection.valid_type?(:foobar)
+      end
+
+      def test_primary_key
+        with_example_table do
+          assert_equal 'id', @connection.primary_key('ex')
+        end
+      end
+
+      def test_primary_key_works_tables_containing_capital_letters
+        assert_equal 'id', @connection.primary_key('CamelCase')
+      end
+
+      def test_non_standard_primary_key
+        with_example_table 'data character varying(255) primary key' do
+          assert_equal 'data', @connection.primary_key('ex')
+        end
+      end
+
+      def test_primary_key_returns_nil_for_no_pk
+        with_example_table 'id integer' do
+          assert_nil @connection.primary_key('ex')
+        end
+      end
+
+      def test_primary_key_raises_error_if_table_not_found
+        assert_raises(ActiveRecord::StatementInvalid) do
+          @connection.primary_key('unobtainium')
+        end
+      end
+
+      def test_insert_sql_with_proprietary_returning_clause
+        with_example_table do
+          id = @connection.insert_sql("insert into ex (number) values(5150)", nil, "number")
+          assert_equal "5150", id
+        end
+      end
+
+      def test_insert_sql_with_quoted_schema_and_table_name
+        with_example_table do
+          id = @connection.insert_sql('insert into "public"."ex" (number) values(5150)')
+          expect = @connection.query('select max(id) from ex').first.first
+          assert_equal expect, id
+        end
+      end
+
+      def test_insert_sql_with_no_space_after_table_name
+        with_example_table do
+          id = @connection.insert_sql("insert into ex(number) values(5150)")
+          expect = @connection.query('select max(id) from ex').first.first
+          assert_equal expect, id
+        end
+      end
+
+      def test_multiline_insert_sql
+        with_example_table do
+          id = @connection.insert_sql(<<-SQL)
+          insert into ex(
+                         number)
+          values(
+                 5152
+                 )
+          SQL
+          expect = @connection.query('select max(id) from ex').first.first
+          assert_equal expect, id
+        end
+      end
+
+      def test_insert_sql_with_returning_disabled
+        connection = connection_without_insert_returning
+        id = connection.insert_sql("insert into postgresql_partitioned_table_parent (number) VALUES (1)")
+        expect = connection.query('select max(id) from postgresql_partitioned_table_parent').first.first
+        assert_equal expect, id
+      end
+
+      def test_exec_insert_with_returning_disabled
+        connection = connection_without_insert_returning
+        result = connection.exec_insert("insert into postgresql_partitioned_table_parent (number) VALUES (1)", nil, [], 'id', 'postgresql_partitioned_table_parent_id_seq')
+        expect = connection.query('select max(id) from postgresql_partitioned_table_parent').first.first
+        assert_equal expect, result.rows.first.first
+      end
+
+      def test_exec_insert_with_returning_disabled_and_no_sequence_name_given
+        connection = connection_without_insert_returning
+        result = connection.exec_insert("insert into postgresql_partitioned_table_parent (number) VALUES (1)", nil, [], 'id')
+        expect = connection.query('select max(id) from postgresql_partitioned_table_parent').first.first
+        assert_equal expect, result.rows.first.first
+      end
+
+      def test_sql_for_insert_with_returning_disabled
+        connection = connection_without_insert_returning
+        result = connection.sql_for_insert('sql', nil, nil, nil, 'binds')
+        assert_equal ['sql', 'binds'], result
+      end
+
+      def test_serial_sequence
+        assert_equal 'public.accounts_id_seq',
+          @connection.serial_sequence('accounts', 'id')
+
+        assert_raises(ActiveRecord::StatementInvalid) do
+          @connection.serial_sequence('zomg', 'id')
+        end
+      end
+
+      def test_default_sequence_name
+        assert_equal PostgreSQL::Name.new('public', 'accounts_id_seq'),
+          @connection.default_sequence_name('accounts', 'id')
+
+        assert_equal PostgreSQL::Name.new('public', 'accounts_id_seq'),
+          @connection.default_sequence_name('accounts')
+      end
+
+      def test_default_sequence_name_bad_table
+        assert_equal PostgreSQL::Name.new(nil, 'zomg_id_seq'),
+          @connection.default_sequence_name('zomg', 'id')
+
+        assert_equal PostgreSQL::Name.new(nil, 'zomg_id_seq'),
+          @connection.default_sequence_name('zomg')
+      end
+
+      def test_pk_and_sequence_for
+        with_example_table do
+          pk, seq = @connection.pk_and_sequence_for('ex')
+          assert_equal 'id', pk
+          assert_equal @connection.default_sequence_name('ex', 'id'), seq
+        end
+      end
+
+      def test_pk_and_sequence_for_with_non_standard_primary_key
+        with_example_table 'code serial primary key' do
+          pk, seq = @connection.pk_and_sequence_for('ex')
+          assert_equal 'code', pk
+          assert_equal @connection.default_sequence_name('ex', 'code'), seq
+        end
+      end
+
+      def test_pk_and_sequence_for_returns_nil_if_no_seq
+        with_example_table 'id integer primary key' do
+          assert_nil @connection.pk_and_sequence_for('ex')
+        end
+      end
+
+      def test_pk_and_sequence_for_returns_nil_if_no_pk
+        with_example_table 'id integer' do
+          assert_nil @connection.pk_and_sequence_for('ex')
+        end
+      end
+
+      def test_pk_and_sequence_for_returns_nil_if_table_not_found
+        assert_nil @connection.pk_and_sequence_for('unobtainium')
+      end
+
+      def test_pk_and_sequence_for_with_collision_pg_class_oid
+        @connection.exec_query('create table ex(id serial primary key)')
+        @connection.exec_query('create table ex2(id serial primary key)')
+
+        correct_depend_record = [
+          "'pg_class'::regclass",
+          "'ex_id_seq'::regclass",
+          '0',
+          "'pg_class'::regclass",
+          "'ex'::regclass",
+          '1',
+          "'a'"
+        ]
+
+        collision_depend_record = [
+          "'pg_attrdef'::regclass",
+          "'ex2_id_seq'::regclass",
+          '0',
+          "'pg_class'::regclass",
+          "'ex'::regclass",
+          '1',
+          "'a'"
+        ]
+
+        @connection.exec_query(
+          "DELETE FROM pg_depend WHERE objid = 'ex_id_seq'::regclass AND refobjid = 'ex'::regclass AND deptype = 'a'"
+        )
+        @connection.exec_query(
+          "INSERT INTO pg_depend VALUES(#{collision_depend_record.join(',')})"
+        )
+        @connection.exec_query(
+          "INSERT INTO pg_depend VALUES(#{correct_depend_record.join(',')})"
+        )
+
+        seq = @connection.pk_and_sequence_for('ex').last
+        assert_equal PostgreSQL::Name.new("public", "ex_id_seq"), seq
+
+        @connection.exec_query(
+          "DELETE FROM pg_depend WHERE objid = 'ex2_id_seq'::regclass AND refobjid = 'ex'::regclass AND deptype = 'a'"
+        )
+      ensure
+        @connection.exec_query('DROP TABLE IF EXISTS ex')
+        @connection.exec_query('DROP TABLE IF EXISTS ex2')
+      end
+
+      def test_exec_insert_number
+        with_example_table do
+          insert(@connection, 'number' => 10)
+
+          result = @connection.exec_query('SELECT number FROM ex WHERE number = 10')
+
+          assert_equal 1, result.rows.length
+          assert_equal "10", result.rows.last.last
+        end
+      end
+
+      def test_exec_insert_string
+        with_example_table do
+          str = 'いただきます！'
+          insert(@connection, 'number' => 10, 'data' => str)
+
+          result = @connection.exec_query('SELECT number, data FROM ex WHERE number = 10')
+
+          value = result.rows.last.last
+
+          assert_equal str, value
+        end
+      end
+
+      def test_table_alias_length
+        assert_nothing_raised do
+          @connection.table_alias_length
+        end
+      end
+
+      def test_exec_no_binds
+        with_example_table do
+          result = @connection.exec_query('SELECT id, data FROM ex')
+          assert_equal 0, result.rows.length
+          assert_equal 2, result.columns.length
+          assert_equal %w{ id data }, result.columns
+
+          string = @connection.quote('foo')
+          @connection.exec_query("INSERT INTO ex (id, data) VALUES (1, #{string})")
+          result = @connection.exec_query('SELECT id, data FROM ex')
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [['1', 'foo']], result.rows
+        end
+      end
+
+      def test_exec_with_binds
+        with_example_table do
+          string = @connection.quote('foo')
+          @connection.exec_query("INSERT INTO ex (id, data) VALUES (1, #{string})")
+          result = @connection.exec_query(
+                                          'SELECT id, data FROM ex WHERE id = $1', nil, [[nil, 1]])
+
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [['1', 'foo']], result.rows
+        end
+      end
+
+      def test_exec_typecasts_bind_vals
+        with_example_table do
+          string = @connection.quote('foo')
+          @connection.exec_query("INSERT INTO ex (id, data) VALUES (1, #{string})")
+
+          column = @connection.columns('ex').find { |col| col.name == 'id' }
+          result = @connection.exec_query(
+                                          'SELECT id, data FROM ex WHERE id = $1', nil, [[column, '1-fuu']])
+
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [['1', 'foo']], result.rows
+        end
+      end
+
+      def test_substitute_at
+        bind = @connection.substitute_at(nil, 0)
+        assert_equal Arel.sql('$1'), bind
+
+        bind = @connection.substitute_at(nil, 1)
+        assert_equal Arel.sql('$2'), bind
+      end
+
+      def test_partial_index
+        with_example_table do
+          @connection.add_index 'ex', %w{ id number }, :name => 'partial', :where => "number > 100"
+          index = @connection.indexes('ex').find { |idx| idx.name == 'partial' }
+          assert_equal "(number > 100)", index.where
+        end
+      end
+
+      def test_columns_for_distinct_zero_orders
+        assert_equal "posts.id",
+          @connection.columns_for_distinct("posts.id", [])
+      end
+
+      def test_columns_for_distinct_one_order
+        assert_equal "posts.id, posts.created_at AS alias_0",
+          @connection.columns_for_distinct("posts.id", ["posts.created_at desc"])
+      end
+
+      def test_columns_for_distinct_few_orders
+        assert_equal "posts.id, posts.created_at AS alias_0, posts.position AS alias_1",
+          @connection.columns_for_distinct("posts.id", ["posts.created_at desc", "posts.position asc"])
+      end
+
+      def test_columns_for_distinct_blank_not_nil_orders
+        assert_equal "posts.id, posts.created_at AS alias_0",
+          @connection.columns_for_distinct("posts.id", ["posts.created_at desc", "", "   "])
+      end
+
+      def test_columns_for_distinct_with_arel_order
+        order = Object.new
+        def order.to_sql
+          "posts.created_at desc"
+        end
+        assert_equal "posts.id, posts.created_at AS alias_0",
+          @connection.columns_for_distinct("posts.id", [order])
+      end
+
+      def test_columns_for_distinct_with_nulls
+        assert_equal "posts.title, posts.updater_id AS alias_0", @connection.columns_for_distinct("posts.title", ["posts.updater_id desc nulls first"])
+        assert_equal "posts.title, posts.updater_id AS alias_0", @connection.columns_for_distinct("posts.title", ["posts.updater_id desc nulls last"])
+      end
+
+      def test_columns_for_distinct_without_order_specifiers
+        assert_equal "posts.title, posts.updater_id AS alias_0",
+          @connection.columns_for_distinct("posts.title", ["posts.updater_id"])
+
+        assert_equal "posts.title, posts.updater_id AS alias_0",
+          @connection.columns_for_distinct("posts.title", ["posts.updater_id nulls last"])
+
+        assert_equal "posts.title, posts.updater_id AS alias_0",
+          @connection.columns_for_distinct("posts.title", ["posts.updater_id nulls first"])
+      end
+
+      def test_raise_error_when_cannot_translate_exception
+        assert_raise TypeError do
+          @connection.send(:log, nil) { @connection.execute(nil) }
+        end
+      end
+
+      def test_reload_type_map_for_newly_defined_types
+        @connection.execute "CREATE TYPE feeling AS ENUM ('good', 'bad')"
+        result = @connection.select_all "SELECT 'good'::feeling"
+        assert_instance_of(PostgreSQLAdapter::OID::Enum,
+                           result.column_types["feeling"])
+      ensure
+        @connection.execute "DROP TYPE IF EXISTS feeling"
+        reset_connection
+      end
+
+      def test_only_reload_type_map_once_for_every_unknown_type
+        silence_warnings do
+          assert_queries 2, ignore_none: true do
+            @connection.select_all "SELECT NULL::anyelement"
+          end
+          assert_queries 1, ignore_none: true do
+            @connection.select_all "SELECT NULL::anyelement"
+          end
+          assert_queries 2, ignore_none: true do
+            @connection.select_all "SELECT NULL::anyarray"
+          end
+        end
+      ensure
+        reset_connection
+      end
+
+      def test_only_warn_on_first_encounter_of_unknown_oid
+        warning = capture(:stderr) {
+          @connection.select_all "SELECT NULL::anyelement"
+          @connection.select_all "SELECT NULL::anyelement"
+          @connection.select_all "SELECT NULL::anyelement"
+        }
+        assert_match(/\Aunknown OID \d+: failed to recognize type of 'anyelement'. It will be treated as String.\n\z/, warning)
+      ensure
+        reset_connection
+      end
+
+      def test_unparsed_defaults_are_at_least_set_when_saving
+        with_example_table "id SERIAL PRIMARY KEY, number INTEGER NOT NULL DEFAULT (4 + 4) * 2 / 4" do
+          number_klass = Class.new(ActiveRecord::Base) do
+            self.table_name = 'ex'
+          end
+          column = number_klass.columns_hash["number"]
+          assert_nil column.default
+          assert_nil column.default_function
+
+          first_number = number_klass.new
+          assert_nil first_number.number
+
+          first_number.save!
+          assert_equal 4, first_number.reload.number
+        end
+      end
+
+      private
+      def insert(ctx, data)
+        binds   = data.map { |name, value|
+          [ctx.columns('ex').find { |x| x.name == name }, value]
+        }
+        columns = binds.map(&:first).map(&:name)
+
+        bind_subs = columns.length.times.map { |x| "$#{x + 1}" }
+
+        sql = "INSERT INTO ex (#{columns.join(", ")})
+               VALUES (#{bind_subs.join(', ')})"
+
+        ctx.exec_insert(sql, 'SQL', binds)
+      end
+
+      def with_example_table(definition = 'id serial primary key, number integer, data character varying(255)', &block)
+        super(@connection, 'ex', definition, &block)
+      end
+
+      def connection_without_insert_returning
+        ActiveRecord::Base.postgresql_connection(ActiveRecord::Base.configurations['arunit'].merge(:insert_returning => false))
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/quoting_test.rb b/activerecord/test/cases/adapters/postgresql/quoting_test.rb
new file mode 100644
index 0000000000..11d5173d37
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/quoting_test.rb
@@ -0,0 +1,74 @@
+require "cases/helper"
+require 'ipaddr'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLAdapter
+      class QuotingTest < ActiveRecord::TestCase
+        def setup
+          @conn = ActiveRecord::Base.connection
+        end
+
+        def test_type_cast_true
+          c = PostgreSQLColumn.new(nil, 1, Type::Boolean.new, 'boolean')
+          assert_equal 't', @conn.type_cast(true, nil)
+          assert_equal 't', @conn.type_cast(true, c)
+        end
+
+        def test_type_cast_false
+          c = PostgreSQLColumn.new(nil, 1, Type::Boolean.new, 'boolean')
+          assert_equal 'f', @conn.type_cast(false, nil)
+          assert_equal 'f', @conn.type_cast(false, c)
+        end
+
+        def test_type_cast_cidr
+          ip = IPAddr.new('255.0.0.0/8')
+          c = PostgreSQLColumn.new(nil, ip, OID::Cidr.new, 'cidr')
+          assert_equal ip, @conn.type_cast(ip, c)
+        end
+
+        def test_type_cast_inet
+          ip = IPAddr.new('255.1.0.0/8')
+          c = PostgreSQLColumn.new(nil, ip, OID::Cidr.new, 'inet')
+          assert_equal ip, @conn.type_cast(ip, c)
+        end
+
+        def test_quote_float_nan
+          nan = 0.0/0
+          c = PostgreSQLColumn.new(nil, 1, OID::Float.new, 'float')
+          assert_equal "'NaN'", @conn.quote(nan, c)
+        end
+
+        def test_quote_float_infinity
+          infinity = 1.0/0
+          c = PostgreSQLColumn.new(nil, 1, OID::Float.new, 'float')
+          assert_equal "'Infinity'", @conn.quote(infinity, c)
+        end
+
+        def test_quote_cast_numeric
+          fixnum = 666
+          c = PostgreSQLColumn.new(nil, nil, Type::String.new, 'varchar')
+          assert_equal "'666'", @conn.quote(fixnum, c)
+          c = PostgreSQLColumn.new(nil, nil, Type::Text.new, 'text')
+          assert_equal "'666'", @conn.quote(fixnum, c)
+        end
+
+        def test_quote_time_usec
+          assert_equal "'1970-01-01 00:00:00.000000'", @conn.quote(Time.at(0))
+          assert_equal "'1970-01-01 00:00:00.000000'", @conn.quote(Time.at(0).to_datetime)
+        end
+
+        def test_quote_range
+          range = "1,2]'; SELECT * FROM users; --".."a"
+          c = PostgreSQLColumn.new(nil, nil, OID::Range.new(Type::Integer.new, :int8range))
+          assert_equal "'[1,0]'", @conn.quote(range, c)
+        end
+
+        def test_quote_bit_string
+          c = PostgreSQLColumn.new(nil, 1, OID::Bit.new)
+          assert_equal nil, @conn.quote("'); SELECT * FROM users; /*\n01\n*/--", c)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/range_test.rb b/activerecord/test/cases/adapters/postgresql/range_test.rb
new file mode 100644
index 0000000000..d812cd01c4
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/range_test.rb
@@ -0,0 +1,323 @@
+require "cases/helper"
+require 'support/connection_helper'
+
+if ActiveRecord::Base.connection.supports_ranges?
+  class PostgresqlRange < ActiveRecord::Base
+    self.table_name = "postgresql_ranges"
+  end
+
+  class PostgresqlRangeTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+    include ConnectionHelper
+
+    def setup
+      @connection = PostgresqlRange.connection
+      begin
+        @connection.transaction do
+          @connection.execute <<_SQL
+            CREATE TYPE floatrange AS RANGE (
+                subtype = float8,
+                subtype_diff = float8mi
+            );
+_SQL
+
+          @connection.create_table('postgresql_ranges') do |t|
+            t.daterange :date_range
+            t.numrange :num_range
+            t.tsrange :ts_range
+            t.tstzrange :tstz_range
+            t.int4range :int4_range
+            t.int8range :int8_range
+          end
+
+          @connection.add_column 'postgresql_ranges', 'float_range', 'floatrange'
+        end
+        PostgresqlRange.reset_column_information
+      rescue ActiveRecord::StatementInvalid
+        skip "do not test on PG without range"
+      end
+
+      insert_range(id: 101,
+                   date_range: "[''2012-01-02'', ''2012-01-04'']",
+                   num_range: "[0.1, 0.2]",
+                   ts_range: "[''2010-01-01 14:30'', ''2011-01-01 14:30'']",
+                   tstz_range: "[''2010-01-01 14:30:00+05'', ''2011-01-01 14:30:00-03'']",
+                   int4_range: "[1, 10]",
+                   int8_range: "[10, 100]",
+                   float_range: "[0.5, 0.7]")
+
+      insert_range(id: 102,
+                   date_range: "[''2012-01-02'', ''2012-01-04'')",
+                   num_range: "[0.1, 0.2)",
+                   ts_range: "[''2010-01-01 14:30'', ''2011-01-01 14:30'')",
+                   tstz_range: "[''2010-01-01 14:30:00+05'', ''2011-01-01 14:30:00-03'')",
+                   int4_range: "[1, 10)",
+                   int8_range: "[10, 100)",
+                   float_range: "[0.5, 0.7)")
+
+      insert_range(id: 103,
+                   date_range: "[''2012-01-02'',]",
+                   num_range: "[0.1,]",
+                   ts_range: "[''2010-01-01 14:30'',]",
+                   tstz_range: "[''2010-01-01 14:30:00+05'',]",
+                   int4_range: "[1,]",
+                   int8_range: "[10,]",
+                   float_range: "[0.5,]")
+
+      insert_range(id: 104,
+                   date_range: "[,]",
+                   num_range: "[,]",
+                   ts_range: "[,]",
+                   tstz_range: "[,]",
+                   int4_range: "[,]",
+                   int8_range: "[,]",
+                   float_range: "[,]")
+
+      insert_range(id: 105,
+                   date_range: "[''2012-01-02'', ''2012-01-02'')",
+                   num_range: "[0.1, 0.1)",
+                   ts_range: "[''2010-01-01 14:30'', ''2010-01-01 14:30'')",
+                   tstz_range: "[''2010-01-01 14:30:00+05'', ''2010-01-01 06:30:00-03'')",
+                   int4_range: "[1, 1)",
+                   int8_range: "[10, 10)",
+                   float_range: "[0.5, 0.5)")
+
+      @new_range = PostgresqlRange.new
+      @first_range = PostgresqlRange.find(101)
+      @second_range = PostgresqlRange.find(102)
+      @third_range = PostgresqlRange.find(103)
+      @fourth_range = PostgresqlRange.find(104)
+      @empty_range = PostgresqlRange.find(105)
+    end
+
+    teardown do
+      @connection.execute 'DROP TABLE IF EXISTS postgresql_ranges'
+      @connection.execute 'DROP TYPE IF EXISTS floatrange'
+      reset_connection
+    end
+
+    def test_data_type_of_range_types
+      assert_equal :daterange, @first_range.column_for_attribute(:date_range).type
+      assert_equal :numrange, @first_range.column_for_attribute(:num_range).type
+      assert_equal :tsrange, @first_range.column_for_attribute(:ts_range).type
+      assert_equal :tstzrange, @first_range.column_for_attribute(:tstz_range).type
+      assert_equal :int4range, @first_range.column_for_attribute(:int4_range).type
+      assert_equal :int8range, @first_range.column_for_attribute(:int8_range).type
+    end
+
+    def test_int4range_values
+      assert_equal 1...11, @first_range.int4_range
+      assert_equal 1...10, @second_range.int4_range
+      assert_equal 1...Float::INFINITY, @third_range.int4_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.int4_range)
+      assert_nil @empty_range.int4_range
+    end
+
+    def test_int8range_values
+      assert_equal 10...101, @first_range.int8_range
+      assert_equal 10...100, @second_range.int8_range
+      assert_equal 10...Float::INFINITY, @third_range.int8_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.int8_range)
+      assert_nil @empty_range.int8_range
+    end
+
+    def test_daterange_values
+      assert_equal Date.new(2012, 1, 2)...Date.new(2012, 1, 5), @first_range.date_range
+      assert_equal Date.new(2012, 1, 2)...Date.new(2012, 1, 4), @second_range.date_range
+      assert_equal Date.new(2012, 1, 2)...Float::INFINITY, @third_range.date_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.date_range)
+      assert_nil @empty_range.date_range
+    end
+
+    def test_numrange_values
+      assert_equal BigDecimal.new('0.1')..BigDecimal.new('0.2'), @first_range.num_range
+      assert_equal BigDecimal.new('0.1')...BigDecimal.new('0.2'), @second_range.num_range
+      assert_equal BigDecimal.new('0.1')...BigDecimal.new('Infinity'), @third_range.num_range
+      assert_equal BigDecimal.new('-Infinity')...BigDecimal.new('Infinity'), @fourth_range.num_range
+      assert_nil @empty_range.num_range
+    end
+
+    def test_tsrange_values
+      tz = ::ActiveRecord::Base.default_timezone
+      assert_equal Time.send(tz, 2010, 1, 1, 14, 30, 0)..Time.send(tz, 2011, 1, 1, 14, 30, 0), @first_range.ts_range
+      assert_equal Time.send(tz, 2010, 1, 1, 14, 30, 0)...Time.send(tz, 2011, 1, 1, 14, 30, 0), @second_range.ts_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.ts_range)
+      assert_nil @empty_range.ts_range
+    end
+
+    def test_tstzrange_values
+      assert_equal Time.parse('2010-01-01 09:30:00 UTC')..Time.parse('2011-01-01 17:30:00 UTC'), @first_range.tstz_range
+      assert_equal Time.parse('2010-01-01 09:30:00 UTC')...Time.parse('2011-01-01 17:30:00 UTC'), @second_range.tstz_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.tstz_range)
+      assert_nil @empty_range.tstz_range
+    end
+
+    def test_custom_range_values
+      assert_equal 0.5..0.7, @first_range.float_range
+      assert_equal 0.5...0.7, @second_range.float_range
+      assert_equal 0.5...Float::INFINITY, @third_range.float_range
+      assert_equal(-Float::INFINITY...Float::INFINITY, @fourth_range.float_range)
+      assert_nil @empty_range.float_range
+    end
+
+    def test_create_tstzrange
+      tstzrange = Time.parse('2010-01-01 14:30:00 +0100')...Time.parse('2011-02-02 14:30:00 CDT')
+      round_trip(@new_range, :tstz_range, tstzrange)
+      assert_equal @new_range.tstz_range, tstzrange
+      assert_equal @new_range.tstz_range, Time.parse('2010-01-01 13:30:00 UTC')...Time.parse('2011-02-02 19:30:00 UTC')
+    end
+
+    def test_update_tstzrange
+      assert_equal_round_trip(@first_range, :tstz_range,
+                              Time.parse('2010-01-01 14:30:00 CDT')...Time.parse('2011-02-02 14:30:00 CET'))
+      assert_nil_round_trip(@first_range, :tstz_range,
+                            Time.parse('2010-01-01 14:30:00 +0100')...Time.parse('2010-01-01 13:30:00 +0000'))
+    end
+
+    def test_create_tsrange
+      tz = ::ActiveRecord::Base.default_timezone
+      assert_equal_round_trip(@new_range, :ts_range,
+                              Time.send(tz, 2010, 1, 1, 14, 30, 0)...Time.send(tz, 2011, 2, 2, 14, 30, 0))
+    end
+
+    def test_update_tsrange
+      tz = ::ActiveRecord::Base.default_timezone
+      assert_equal_round_trip(@first_range, :ts_range,
+                              Time.send(tz, 2010, 1, 1, 14, 30, 0)...Time.send(tz, 2011, 2, 2, 14, 30, 0))
+      assert_nil_round_trip(@first_range, :ts_range,
+                            Time.send(tz, 2010, 1, 1, 14, 30, 0)...Time.send(tz, 2010, 1, 1, 14, 30, 0))
+    end
+
+    def test_create_numrange
+      assert_equal_round_trip(@new_range, :num_range,
+                              BigDecimal.new('0.5')...BigDecimal.new('1'))
+    end
+
+    def test_update_numrange
+      assert_equal_round_trip(@first_range, :num_range,
+                              BigDecimal.new('0.5')...BigDecimal.new('1'))
+      assert_nil_round_trip(@first_range, :num_range,
+                            BigDecimal.new('0.5')...BigDecimal.new('0.5'))
+    end
+
+    def test_create_daterange
+      assert_equal_round_trip(@new_range, :date_range,
+                              Range.new(Date.new(2012, 1, 1), Date.new(2013, 1, 1), true))
+    end
+
+    def test_update_daterange
+      assert_equal_round_trip(@first_range, :date_range,
+                              Date.new(2012, 2, 3)...Date.new(2012, 2, 10))
+      assert_nil_round_trip(@first_range, :date_range,
+                            Date.new(2012, 2, 3)...Date.new(2012, 2, 3))
+    end
+
+    def test_create_int4range
+      assert_equal_round_trip(@new_range, :int4_range, Range.new(3, 50, true))
+    end
+
+    def test_update_int4range
+      assert_equal_round_trip(@first_range, :int4_range, 6...10)
+      assert_nil_round_trip(@first_range, :int4_range, 3...3)
+    end
+
+    def test_create_int8range
+      assert_equal_round_trip(@new_range, :int8_range, Range.new(30, 50, true))
+    end
+
+    def test_update_int8range
+      assert_equal_round_trip(@first_range, :int8_range, 60000...10000000)
+      assert_nil_round_trip(@first_range, :int8_range, 39999...39999)
+    end
+
+    def test_exclude_beginning_for_subtypes_with_succ_method_is_deprecated
+      tz = ::ActiveRecord::Base.default_timezone
+
+      silence_warnings {
+        assert_deprecated {
+          range = PostgresqlRange.create!(date_range: "(''2012-01-02'', ''2012-01-04'']")
+          assert_equal Date.new(2012, 1, 3)..Date.new(2012, 1, 4), range.date_range
+        }
+        assert_deprecated {
+          range = PostgresqlRange.create!(ts_range: "(''2010-01-01 14:30'', ''2011-01-01 14:30'']")
+          assert_equal Time.send(tz, 2010, 1, 1, 14, 30, 1)..Time.send(tz, 2011, 1, 1, 14, 30, 0), range.ts_range
+        }
+        assert_deprecated {
+          range = PostgresqlRange.create!(tstz_range: "(''2010-01-01 14:30:00+05'', ''2011-01-01 14:30:00-03'']")
+          assert_equal Time.parse('2010-01-01 09:30:01 UTC')..Time.parse('2011-01-01 17:30:00 UTC'), range.tstz_range
+        }
+        assert_deprecated {
+          range = PostgresqlRange.create!(int4_range: "(1, 10]")
+          assert_equal 2..10, range.int4_range
+        }
+        assert_deprecated {
+          range = PostgresqlRange.create!(int8_range: "(10, 100]")
+          assert_equal 11..100, range.int8_range
+        }
+      }
+    end
+
+    def test_exclude_beginning_for_subtypes_without_succ_method_is_not_supported
+      assert_raises(ArgumentError) { PostgresqlRange.create!(num_range: "(0.1, 0.2]") }
+      assert_raises(ArgumentError) { PostgresqlRange.create!(float_range: "(0.5, 0.7]") }
+    end
+
+    def test_update_all_with_ranges
+      PostgresqlRange.create!
+
+      PostgresqlRange.update_all(int8_range: 1..100)
+
+      assert_equal 1...101, PostgresqlRange.first.int8_range
+    end
+
+    def test_ranges_correctly_escape_input
+      range = "-1,2]'; DROP TABLE postgresql_ranges; --".."a"
+      PostgresqlRange.update_all(int8_range: range)
+
+      assert_nothing_raised do
+        PostgresqlRange.first
+      end
+    end
+
+    private
+      def assert_equal_round_trip(range, attribute, value)
+        round_trip(range, attribute, value)
+        assert_equal value, range.public_send(attribute)
+      end
+
+      def assert_nil_round_trip(range, attribute, value)
+        round_trip(range, attribute, value)
+        assert_nil range.public_send(attribute)
+      end
+
+      def round_trip(range, attribute, value)
+        range.public_send "#{attribute}=", value
+        assert range.save
+        assert range.reload
+      end
+
+      def insert_range(values)
+        @connection.execute <<-SQL
+          INSERT INTO postgresql_ranges (
+            id,
+            date_range,
+            num_range,
+            ts_range,
+            tstz_range,
+            int4_range,
+            int8_range,
+            float_range
+          ) VALUES (
+            #{values[:id]},
+            '#{values[:date_range]}',
+            '#{values[:num_range]}',
+            '#{values[:ts_range]}',
+            '#{values[:tstz_range]}',
+            '#{values[:int4_range]}',
+            '#{values[:int8_range]}',
+            '#{values[:float_range]}'
+          )
+        SQL
+      end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb b/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb
new file mode 100644
index 0000000000..99c26c4bf7
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb
@@ -0,0 +1,114 @@
+require "cases/helper"
+
+class SchemaThing < ActiveRecord::Base
+end
+
+class SchemaAuthorizationTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  TABLE_NAME = 'schema_things'
+  COLUMNS = [
+    'id serial primary key',
+    'name character varying(50)'
+  ]
+  USERS = ['rails_pg_schema_user1', 'rails_pg_schema_user2']
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.execute "SET search_path TO '$user',public"
+    set_session_auth
+    USERS.each do |u|
+      @connection.execute "CREATE USER #{u}" rescue nil
+      @connection.execute "CREATE SCHEMA AUTHORIZATION #{u}" rescue nil
+      set_session_auth u
+      @connection.execute "CREATE TABLE #{TABLE_NAME} (#{COLUMNS.join(',')})"
+      @connection.execute "INSERT INTO #{TABLE_NAME} (name) VALUES ('#{u}')"
+      set_session_auth
+    end
+  end
+
+  teardown do
+    set_session_auth
+    @connection.execute "RESET search_path"
+    USERS.each do |u|
+      @connection.execute "DROP SCHEMA #{u} CASCADE"
+      @connection.execute "DROP USER #{u}"
+    end
+  end
+
+  def test_schema_invisible
+    assert_raise(ActiveRecord::StatementInvalid) do
+      set_session_auth
+      @connection.execute "SELECT * FROM #{TABLE_NAME}"
+    end
+  end
+
+  def test_session_auth=
+    assert_raise(ActiveRecord::StatementInvalid) do
+      @connection.session_auth = 'DEFAULT'
+      @connection.execute "SELECT * FROM #{TABLE_NAME}"
+    end
+  end
+
+  def test_setting_auth_clears_stmt_cache
+    assert_nothing_raised do
+      set_session_auth
+      USERS.each do |u|
+        set_session_auth u
+        assert_equal u, @connection.exec_query("SELECT name FROM #{TABLE_NAME} WHERE id = $1", 'SQL', [[nil, 1]]).first['name']
+        set_session_auth
+      end
+    end
+  end
+
+  def test_auth_with_bind
+    assert_nothing_raised do
+      set_session_auth
+      USERS.each do |u|
+        @connection.clear_cache!
+        set_session_auth u
+        assert_equal u, @connection.exec_query("SELECT name FROM #{TABLE_NAME} WHERE id = $1", 'SQL', [[nil, 1]]).first['name']
+        set_session_auth
+      end
+    end
+  end
+
+  def test_schema_uniqueness
+    assert_nothing_raised do
+      set_session_auth
+      USERS.each do |u|
+        set_session_auth u
+        assert_equal u, @connection.select_value("SELECT name FROM #{TABLE_NAME} WHERE id = 1")
+        set_session_auth
+      end
+    end
+  end
+
+  def test_sequence_schema_caching
+    assert_nothing_raised do
+      USERS.each do |u|
+        set_session_auth u
+        st = SchemaThing.new :name => 'TEST1'
+        st.save!
+        st = SchemaThing.new :id => 5, :name => 'TEST2'
+        st.save!
+        set_session_auth
+      end
+    end
+  end
+
+  def test_tables_in_current_schemas
+    assert !@connection.tables.include?(TABLE_NAME)
+    USERS.each do |u|
+      set_session_auth u
+      assert @connection.tables.include?(TABLE_NAME)
+      set_session_auth
+    end
+  end
+
+  private
+    def set_session_auth auth = nil
+       @connection.session_auth =  auth || 'default'
+    end
+
+end
diff --git a/activerecord/test/cases/adapters/postgresql/schema_test.rb b/activerecord/test/cases/adapters/postgresql/schema_test.rb
new file mode 100644
index 0000000000..9e5fd17dc4
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/schema_test.rb
@@ -0,0 +1,428 @@
+require "cases/helper"
+
+class SchemaTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  SCHEMA_NAME = 'test_schema'
+  SCHEMA2_NAME = 'test_schema2'
+  TABLE_NAME = 'things'
+  CAPITALIZED_TABLE_NAME = 'Things'
+  INDEX_A_NAME = 'a_index_things_on_name'
+  INDEX_B_NAME = 'b_index_things_on_different_columns_in_each_schema'
+  INDEX_C_NAME = 'c_index_full_text_search'
+  INDEX_D_NAME = 'd_index_things_on_description_desc'
+  INDEX_E_NAME = 'e_index_things_on_name_vector'
+  INDEX_A_COLUMN = 'name'
+  INDEX_B_COLUMN_S1 = 'email'
+  INDEX_B_COLUMN_S2 = 'moment'
+  INDEX_C_COLUMN = %q{(to_tsvector('english', coalesce(things.name, '')))}
+  INDEX_D_COLUMN = 'description'
+  INDEX_E_COLUMN = 'name_vector'
+  COLUMNS = [
+    'id integer',
+    'name character varying(50)',
+    'email character varying(50)',
+    'description character varying(100)',
+    'name_vector tsvector',
+    'moment timestamp without time zone default now()'
+  ]
+  PK_TABLE_NAME = 'table_with_pk'
+  UNMATCHED_SEQUENCE_NAME = 'unmatched_primary_key_default_value_seq'
+  UNMATCHED_PK_TABLE_NAME = 'table_with_unmatched_sequence_for_pk'
+
+  class Thing1 < ActiveRecord::Base
+    self.table_name = "test_schema.things"
+  end
+
+  class Thing2 < ActiveRecord::Base
+    self.table_name = "test_schema2.things"
+  end
+
+  class Thing3 < ActiveRecord::Base
+    self.table_name = 'test_schema."things.table"'
+  end
+
+  class Thing4 < ActiveRecord::Base
+    self.table_name = 'test_schema."Things"'
+  end
+
+  class Thing5 < ActiveRecord::Base
+    self.table_name = 'things'
+  end
+
+  class Song < ActiveRecord::Base
+    self.table_name = "music.songs"
+    has_and_belongs_to_many :albums
+  end
+
+  class Album < ActiveRecord::Base
+    self.table_name = "music.albums"
+    has_and_belongs_to_many :songs
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.execute "CREATE SCHEMA #{SCHEMA_NAME} CREATE TABLE #{TABLE_NAME} (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.\"#{TABLE_NAME}.table\" (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.\"#{CAPITALIZED_TABLE_NAME}\" (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE SCHEMA #{SCHEMA2_NAME} CREATE TABLE #{TABLE_NAME} (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE INDEX #{INDEX_A_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_A_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_A_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_A_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_B_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_B_COLUMN_S1});"
+    @connection.execute "CREATE INDEX #{INDEX_B_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_B_COLUMN_S2});"
+    @connection.execute "CREATE INDEX #{INDEX_C_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING gin (#{INDEX_C_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_C_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING gin (#{INDEX_C_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_D_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_D_COLUMN} DESC);"
+    @connection.execute "CREATE INDEX #{INDEX_D_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING btree (#{INDEX_D_COLUMN} DESC);"
+    @connection.execute "CREATE INDEX #{INDEX_E_NAME} ON #{SCHEMA_NAME}.#{TABLE_NAME}  USING gin (#{INDEX_E_COLUMN});"
+    @connection.execute "CREATE INDEX #{INDEX_E_NAME} ON #{SCHEMA2_NAME}.#{TABLE_NAME}  USING gin (#{INDEX_E_COLUMN});"
+    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.#{PK_TABLE_NAME} (id serial primary key)"
+    @connection.execute "CREATE SEQUENCE #{SCHEMA_NAME}.#{UNMATCHED_SEQUENCE_NAME}"
+    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.#{UNMATCHED_PK_TABLE_NAME} (id integer NOT NULL DEFAULT nextval('#{SCHEMA_NAME}.#{UNMATCHED_SEQUENCE_NAME}'::regclass), CONSTRAINT unmatched_pkey PRIMARY KEY (id))"
+  end
+
+  teardown do
+    @connection.execute "DROP SCHEMA #{SCHEMA2_NAME} CASCADE"
+    @connection.execute "DROP SCHEMA #{SCHEMA_NAME} CASCADE"
+  end
+
+  def test_schema_names
+    assert_equal ["public", "schema_1", "test_schema", "test_schema2"], @connection.schema_names
+  end
+
+  def test_create_schema
+    begin
+      @connection.create_schema "test_schema3"
+      assert @connection.schema_names.include? "test_schema3"
+    ensure
+      @connection.drop_schema "test_schema3"
+    end
+  end
+
+  def test_raise_create_schema_with_existing_schema
+    begin
+      @connection.create_schema "test_schema3"
+      assert_raises(ActiveRecord::StatementInvalid) do
+        @connection.create_schema "test_schema3"
+      end
+    ensure
+      @connection.drop_schema "test_schema3"
+    end
+  end
+
+  def test_drop_schema
+    begin
+      @connection.create_schema "test_schema3"
+    ensure
+      @connection.drop_schema "test_schema3"
+    end
+    assert !@connection.schema_names.include?("test_schema3")
+  end
+
+  def test_habtm_table_name_with_schema
+    ActiveRecord::Base.connection.execute <<-SQL
+      DROP SCHEMA IF EXISTS music CASCADE;
+      CREATE SCHEMA music;
+      CREATE TABLE music.albums (id serial primary key);
+      CREATE TABLE music.songs (id serial primary key);
+      CREATE TABLE music.albums_songs (album_id integer, song_id integer);
+    SQL
+
+    song = Song.create
+    Album.create
+    assert_equal song, Song.includes(:albums).references(:albums).first
+  ensure
+    ActiveRecord::Base.connection.execute "DROP SCHEMA music CASCADE;"
+  end
+
+  def test_raise_drop_schema_with_nonexisting_schema
+    assert_raises(ActiveRecord::StatementInvalid) do
+      @connection.drop_schema "test_schema3"
+    end
+  end
+
+  def test_raise_wraped_exception_on_bad_prepare
+    assert_raises(ActiveRecord::StatementInvalid) do
+      @connection.exec_query "select * from developers where id = ?", 'sql', [[nil, 1]]
+    end
+  end
+
+  def test_schema_change_with_prepared_stmt
+    altered = false
+    @connection.exec_query "select * from developers where id = $1", 'sql', [[nil, 1]]
+    @connection.exec_query "alter table developers add column zomg int", 'sql', []
+    altered = true
+    @connection.exec_query "select * from developers where id = $1", 'sql', [[nil, 1]]
+  ensure
+    # We are not using DROP COLUMN IF EXISTS because that syntax is only
+    # supported by pg 9.X
+    @connection.exec_query("alter table developers drop column zomg", 'sql', []) if altered
+  end
+
+  def test_table_exists?
+    [Thing1, Thing2, Thing3, Thing4].each do |klass|
+      name = klass.table_name
+      assert @connection.table_exists?(name), "'#{name}' table should exist"
+    end
+  end
+
+  def test_table_exists_when_on_schema_search_path
+    with_schema_search_path(SCHEMA_NAME) do
+      assert(@connection.table_exists?(TABLE_NAME), "table should exist and be found")
+    end
+  end
+
+  def test_table_exists_when_not_on_schema_search_path
+    with_schema_search_path('PUBLIC') do
+      assert(!@connection.table_exists?(TABLE_NAME), "table exists but should not be found")
+    end
+  end
+
+  def test_table_exists_wrong_schema
+    assert(!@connection.table_exists?("foo.things"), "table should not exist")
+  end
+
+  def test_table_exists_quoted_names
+    [ %("#{SCHEMA_NAME}"."#{TABLE_NAME}"), %(#{SCHEMA_NAME}."#{TABLE_NAME}"), %(#{SCHEMA_NAME}."#{TABLE_NAME}")].each do |given|
+      assert(@connection.table_exists?(given), "table should exist when specified as #{given}")
+    end
+    with_schema_search_path(SCHEMA_NAME) do
+      given = %("#{TABLE_NAME}")
+      assert(@connection.table_exists?(given), "table should exist when specified as #{given}")
+    end
+  end
+
+  def test_table_exists_quoted_table
+    with_schema_search_path(SCHEMA_NAME) do
+        assert(@connection.table_exists?('"things.table"'), "table should exist")
+    end
+  end
+
+  def test_with_schema_prefixed_table_name
+    assert_nothing_raised do
+      assert_equal COLUMNS, columns("#{SCHEMA_NAME}.#{TABLE_NAME}")
+    end
+  end
+
+  def test_with_schema_prefixed_capitalized_table_name
+    assert_nothing_raised do
+      assert_equal COLUMNS, columns("#{SCHEMA_NAME}.#{CAPITALIZED_TABLE_NAME}")
+    end
+  end
+
+  def test_with_schema_search_path
+    assert_nothing_raised do
+      with_schema_search_path(SCHEMA_NAME) do
+        assert_equal COLUMNS, columns(TABLE_NAME)
+      end
+    end
+  end
+
+  def test_proper_encoding_of_table_name
+    assert_equal '"table_name"', @connection.quote_table_name('table_name')
+    assert_equal '"table.name"', @connection.quote_table_name('"table.name"')
+    assert_equal '"schema_name"."table_name"', @connection.quote_table_name('schema_name.table_name')
+    assert_equal '"schema_name"."table.name"', @connection.quote_table_name('schema_name."table.name"')
+    assert_equal '"schema.name"."table_name"', @connection.quote_table_name('"schema.name".table_name')
+    assert_equal '"schema.name"."table.name"', @connection.quote_table_name('"schema.name"."table.name"')
+  end
+
+  def test_classes_with_qualified_schema_name
+    assert_equal 0, Thing1.count
+    assert_equal 0, Thing2.count
+    assert_equal 0, Thing3.count
+    assert_equal 0, Thing4.count
+
+    Thing1.create(:id => 1, :name => "thing1", :email => "thing1@localhost", :moment => Time.now)
+    assert_equal 1, Thing1.count
+    assert_equal 0, Thing2.count
+    assert_equal 0, Thing3.count
+    assert_equal 0, Thing4.count
+
+    Thing2.create(:id => 1, :name => "thing1", :email => "thing1@localhost", :moment => Time.now)
+    assert_equal 1, Thing1.count
+    assert_equal 1, Thing2.count
+    assert_equal 0, Thing3.count
+    assert_equal 0, Thing4.count
+
+    Thing3.create(:id => 1, :name => "thing1", :email => "thing1@localhost", :moment => Time.now)
+    assert_equal 1, Thing1.count
+    assert_equal 1, Thing2.count
+    assert_equal 1, Thing3.count
+    assert_equal 0, Thing4.count
+
+    Thing4.create(:id => 1, :name => "thing1", :email => "thing1@localhost", :moment => Time.now)
+    assert_equal 1, Thing1.count
+    assert_equal 1, Thing2.count
+    assert_equal 1, Thing3.count
+    assert_equal 1, Thing4.count
+  end
+
+  def test_raise_on_unquoted_schema_name
+    assert_raises(ActiveRecord::StatementInvalid) do
+      with_schema_search_path '$user,public'
+    end
+  end
+
+  def test_without_schema_search_path
+    assert_raises(ActiveRecord::StatementInvalid) { columns(TABLE_NAME) }
+  end
+
+  def test_ignore_nil_schema_search_path
+    assert_nothing_raised { with_schema_search_path nil }
+  end
+
+  def test_index_name_exists
+    with_schema_search_path(SCHEMA_NAME) do
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_A_NAME, true)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_B_NAME, true)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_C_NAME, true)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_D_NAME, true)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_E_NAME, true)
+      assert @connection.index_name_exists?(TABLE_NAME, INDEX_E_NAME, true)
+      assert_not @connection.index_name_exists?(TABLE_NAME, 'missing_index', true)
+    end
+  end
+
+  def test_dump_indexes_for_schema_one
+    do_dump_index_tests_for_schema(SCHEMA_NAME, INDEX_A_COLUMN, INDEX_B_COLUMN_S1, INDEX_D_COLUMN, INDEX_E_COLUMN)
+  end
+
+  def test_dump_indexes_for_schema_two
+    do_dump_index_tests_for_schema(SCHEMA2_NAME, INDEX_A_COLUMN, INDEX_B_COLUMN_S2, INDEX_D_COLUMN, INDEX_E_COLUMN)
+  end
+
+  def test_dump_indexes_for_schema_multiple_schemas_in_search_path
+    do_dump_index_tests_for_schema("public, #{SCHEMA_NAME}", INDEX_A_COLUMN, INDEX_B_COLUMN_S1, INDEX_D_COLUMN, INDEX_E_COLUMN)
+  end
+
+  def test_with_uppercase_index_name
+    @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
+    assert_nothing_raised { @connection.remove_index! "things", "#{SCHEMA_NAME}.things_Index"}
+    @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
+
+    with_schema_search_path SCHEMA_NAME do
+      assert_nothing_raised { @connection.remove_index! "things", "things_Index"}
+    end
+  end
+
+  def test_primary_key_with_schema_specified
+    [
+      %("#{SCHEMA_NAME}"."#{PK_TABLE_NAME}"),
+      %(#{SCHEMA_NAME}."#{PK_TABLE_NAME}"),
+      %(#{SCHEMA_NAME}.#{PK_TABLE_NAME})
+    ].each do |given|
+      assert_equal 'id', @connection.primary_key(given), "primary key should be found when table referenced as #{given}"
+    end
+  end
+
+  def test_primary_key_assuming_schema_search_path
+    with_schema_search_path(SCHEMA_NAME) do
+      assert_equal 'id', @connection.primary_key(PK_TABLE_NAME), "primary key should be found"
+    end
+  end
+
+  def test_primary_key_raises_error_if_table_not_found_on_schema_search_path
+    with_schema_search_path(SCHEMA2_NAME) do
+      assert_raises(ActiveRecord::StatementInvalid) do
+        @connection.primary_key(PK_TABLE_NAME)
+      end
+    end
+  end
+
+  def test_pk_and_sequence_for_with_schema_specified
+    pg_name = ActiveRecord::ConnectionAdapters::PostgreSQL::Name
+    [
+      %("#{SCHEMA_NAME}"."#{PK_TABLE_NAME}"),
+      %("#{SCHEMA_NAME}"."#{UNMATCHED_PK_TABLE_NAME}")
+    ].each do |given|
+      pk, seq = @connection.pk_and_sequence_for(given)
+      assert_equal 'id', pk, "primary key should be found when table referenced as #{given}"
+      assert_equal pg_name.new(SCHEMA_NAME, "#{PK_TABLE_NAME}_id_seq"), seq, "sequence name should be found when table referenced as #{given}" if given == %("#{SCHEMA_NAME}"."#{PK_TABLE_NAME}")
+      assert_equal pg_name.new(SCHEMA_NAME, UNMATCHED_SEQUENCE_NAME), seq, "sequence name should be found when table referenced as #{given}" if given ==  %("#{SCHEMA_NAME}"."#{UNMATCHED_PK_TABLE_NAME}")
+    end
+  end
+
+  def test_current_schema
+    {
+      %('$user',public)                        => 'public',
+      SCHEMA_NAME                              => SCHEMA_NAME,
+      %(#{SCHEMA2_NAME},#{SCHEMA_NAME},public) => SCHEMA2_NAME,
+      %(public,#{SCHEMA2_NAME},#{SCHEMA_NAME}) => 'public'
+    }.each do |given,expect|
+      with_schema_search_path(given) { assert_equal expect, @connection.current_schema }
+    end
+  end
+
+  def test_prepared_statements_with_multiple_schemas
+    [SCHEMA_NAME, SCHEMA2_NAME].each do |schema_name|
+      with_schema_search_path schema_name do
+        Thing5.create(:id => 1, :name => "thing inside #{SCHEMA_NAME}", :email => "thing1@localhost", :moment => Time.now)
+      end
+    end
+
+    [SCHEMA_NAME, SCHEMA2_NAME].each do |schema_name|
+      with_schema_search_path schema_name do
+        assert_equal 1, Thing5.count
+      end
+    end
+  end
+
+  def test_schema_exists?
+    {
+      'public'     => true,
+      SCHEMA_NAME  => true,
+      SCHEMA2_NAME => true,
+      'darkside'   => false
+    }.each do |given,expect|
+      assert_equal expect, @connection.schema_exists?(given)
+    end
+  end
+
+  def test_reset_pk_sequence
+    sequence_name = "#{SCHEMA_NAME}.#{UNMATCHED_SEQUENCE_NAME}"
+    @connection.execute "SELECT setval('#{sequence_name}', 123)"
+    assert_equal "124", @connection.select_value("SELECT nextval('#{sequence_name}')")
+    @connection.reset_pk_sequence!("#{SCHEMA_NAME}.#{UNMATCHED_PK_TABLE_NAME}")
+    assert_equal "1", @connection.select_value("SELECT nextval('#{sequence_name}')")
+  end
+
+  private
+    def columns(table_name)
+      @connection.send(:column_definitions, table_name).map do |name, type, default|
+        "#{name} #{type}" + (default ? " default #{default}" : '')
+      end
+    end
+
+    def with_schema_search_path(schema_search_path)
+      @connection.schema_search_path = schema_search_path
+      yield if block_given?
+    ensure
+      @connection.schema_search_path = "'$user', public"
+    end
+
+    def do_dump_index_tests_for_schema(this_schema_name, first_index_column_name, second_index_column_name, third_index_column_name, fourth_index_column_name)
+      with_schema_search_path(this_schema_name) do
+        indexes = @connection.indexes(TABLE_NAME).sort_by {|i| i.name}
+        assert_equal 4,indexes.size
+
+        do_dump_index_assertions_for_one_index(indexes[0], INDEX_A_NAME, first_index_column_name)
+        do_dump_index_assertions_for_one_index(indexes[1], INDEX_B_NAME, second_index_column_name)
+        do_dump_index_assertions_for_one_index(indexes[2], INDEX_D_NAME, third_index_column_name)
+        do_dump_index_assertions_for_one_index(indexes[3], INDEX_E_NAME, fourth_index_column_name)
+
+        indexes.select{|i| i.name != INDEX_E_NAME}.each do |index|
+           assert_equal :btree, index.using
+        end
+        assert_equal :gin, indexes.select{|i| i.name == INDEX_E_NAME}[0].using
+        assert_equal :desc, indexes.select{|i| i.name == INDEX_D_NAME}[0].orders[INDEX_D_COLUMN]
+      end
+    end
+
+    def do_dump_index_assertions_for_one_index(this_index, this_index_name, this_index_column)
+      assert_equal TABLE_NAME, this_index.table
+      assert_equal 1, this_index.columns.size
+      assert_equal this_index_column, this_index.columns[0]
+      assert_equal this_index_name, this_index.name
+    end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/sql_types_test.rb b/activerecord/test/cases/adapters/postgresql/sql_types_test.rb
new file mode 100644
index 0000000000..d7d40f6385
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/sql_types_test.rb
@@ -0,0 +1,18 @@
+require "cases/helper"
+
+class SqlTypesTest < ActiveRecord::TestCase
+  def test_binary_types
+    assert_equal 'bytea', type_to_sql(:binary, 100_000)
+    assert_raise ActiveRecord::ActiveRecordError do
+      type_to_sql :binary, 4294967295
+    end
+    assert_equal 'text', type_to_sql(:text, 100_000)
+    assert_raise ActiveRecord::ActiveRecordError do
+      type_to_sql :text, 4294967295
+    end
+  end
+
+  def type_to_sql(*args)
+    ActiveRecord::Base.connection.type_to_sql(*args)
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb b/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb
new file mode 100644
index 0000000000..1497b0abc7
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb
@@ -0,0 +1,41 @@
+require 'cases/helper'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLAdapter < AbstractAdapter
+      class InactivePGconn
+        def query(*args)
+          raise PGError
+        end
+
+        def status
+          PGconn::CONNECTION_BAD
+        end
+      end
+
+      class StatementPoolTest < ActiveRecord::TestCase
+        if Process.respond_to?(:fork)
+          def test_cache_is_per_pid
+            cache = StatementPool.new nil, 10
+            cache['foo'] = 'bar'
+            assert_equal 'bar', cache['foo']
+
+            pid = fork {
+              lookup = cache['foo'];
+              exit!(!lookup)
+            }
+
+            Process.waitpid pid
+            assert $?.success?, 'process should exit successfully'
+          end
+        end
+
+        def test_dealloc_does_not_raise_on_inactive_connection
+          cache = StatementPool.new InactivePGconn.new, 10
+          cache['foo'] = 'bar'
+          assert_nothing_raised { cache.clear }
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/timestamp_test.rb b/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
new file mode 100644
index 0000000000..3614b29190
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
@@ -0,0 +1,154 @@
+require 'cases/helper'
+require 'models/developer'
+require 'models/topic'
+
+class PostgresqlTimestampTest < ActiveRecord::TestCase
+  class PostgresqlTimestampWithZone < ActiveRecord::Base; end
+
+  self.use_transactional_fixtures = false
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.execute("INSERT INTO postgresql_timestamp_with_zones (id, time) VALUES (1, '2010-01-01 10:00:00-1')")
+  end
+
+  teardown do
+    PostgresqlTimestampWithZone.delete_all
+  end
+
+  def test_timestamp_with_zone_values_with_rails_time_zone_support
+    with_timezone_config default: :utc, aware_attributes: true do
+      @connection.reconnect!
+
+      timestamp = PostgresqlTimestampWithZone.find(1)
+      assert_equal Time.utc(2010,1,1, 11,0,0), timestamp.time
+      assert_instance_of Time, timestamp.time
+    end
+  ensure
+    @connection.reconnect!
+  end
+
+  def test_timestamp_with_zone_values_without_rails_time_zone_support
+    with_timezone_config default: :local, aware_attributes: false do
+      @connection.reconnect!
+      # make sure to use a non-UTC time zone
+      @connection.execute("SET time zone 'America/Jamaica'", 'SCHEMA')
+
+      timestamp = PostgresqlTimestampWithZone.find(1)
+      assert_equal Time.utc(2010,1,1, 11,0,0), timestamp.time
+      assert_instance_of Time, timestamp.time
+    end
+  ensure
+    @connection.reconnect!
+  end
+end
+
+class TimestampTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  def test_group_by_date
+    keys = Topic.group("date_trunc('month', created_at)").count.keys
+    assert_operator keys.length, :>, 0
+    keys.each { |k| assert_kind_of Time, k }
+  end
+
+  def test_load_infinity_and_beyond
+    d = Developer.find_by_sql("select 'infinity'::timestamp as updated_at")
+    assert d.first.updated_at.infinite?, 'timestamp should be infinite'
+
+    d = Developer.find_by_sql("select '-infinity'::timestamp as updated_at")
+    time = d.first.updated_at
+    assert time.infinite?, 'timestamp should be infinite'
+    assert_operator time, :<, 0
+  end
+
+  def test_save_infinity_and_beyond
+    d = Developer.create!(:name => 'aaron', :updated_at => 1.0 / 0.0)
+    assert_equal(1.0 / 0.0, d.updated_at)
+
+    d = Developer.create!(:name => 'aaron', :updated_at => -1.0 / 0.0)
+    assert_equal(-1.0 / 0.0, d.updated_at)
+  end
+
+  def test_default_datetime_precision
+    ActiveRecord::Base.connection.create_table(:foos)
+    ActiveRecord::Base.connection.add_column :foos, :created_at, :datetime
+    ActiveRecord::Base.connection.add_column :foos, :updated_at, :datetime
+    assert_nil activerecord_column_option('foos', 'created_at', 'precision')
+  end
+
+  def test_timestamp_data_type_with_precision
+    ActiveRecord::Base.connection.create_table(:foos)
+    ActiveRecord::Base.connection.add_column :foos, :created_at, :datetime, :precision => 0
+    ActiveRecord::Base.connection.add_column :foos, :updated_at, :datetime, :precision => 5
+    assert_equal 0, activerecord_column_option('foos', 'created_at', 'precision')
+    assert_equal 5, activerecord_column_option('foos', 'updated_at', 'precision')
+  end
+
+  def test_timestamps_helper_with_custom_precision
+    ActiveRecord::Base.connection.create_table(:foos) do |t|
+      t.timestamps :precision => 4
+    end
+    assert_equal 4, activerecord_column_option('foos', 'created_at', 'precision')
+    assert_equal 4, activerecord_column_option('foos', 'updated_at', 'precision')
+  end
+
+  def test_passing_precision_to_timestamp_does_not_set_limit
+    ActiveRecord::Base.connection.create_table(:foos) do |t|
+      t.timestamps :precision => 4
+    end
+    assert_nil activerecord_column_option("foos", "created_at", "limit")
+    assert_nil activerecord_column_option("foos", "updated_at", "limit")
+  end
+
+  def test_invalid_timestamp_precision_raises_error
+    assert_raises ActiveRecord::ActiveRecordError do
+      ActiveRecord::Base.connection.create_table(:foos) do |t|
+        t.timestamps :precision => 7
+      end
+    end
+  end
+
+  def test_postgres_agrees_with_activerecord_about_precision
+    ActiveRecord::Base.connection.create_table(:foos) do |t|
+      t.timestamps :precision => 4
+    end
+    assert_equal '4', pg_datetime_precision('foos', 'created_at')
+    assert_equal '4', pg_datetime_precision('foos', 'updated_at')
+  end
+
+  def test_bc_timestamp
+    date = Date.new(0) - 1.week
+    Developer.create!(:name => "aaron", :updated_at => date)
+    assert_equal date, Developer.find_by_name("aaron").updated_at
+  end
+
+  def test_bc_timestamp_leap_year
+    date = Time.utc(-4, 2, 29)
+    Developer.create!(:name => "taihou", :updated_at => date)
+    assert_equal date, Developer.find_by_name("taihou").updated_at
+  end
+
+  def test_bc_timestamp_year_zero
+    date = Time.utc(0, 4, 7)
+    Developer.create!(:name => "yahagi", :updated_at => date)
+    assert_equal date, Developer.find_by_name("yahagi").updated_at
+  end
+
+  private
+
+  def pg_datetime_precision(table_name, column_name)
+    results = ActiveRecord::Base.connection.execute("SELECT column_name, datetime_precision FROM information_schema.columns WHERE table_name ='#{table_name}'")
+    result = results.find do |result_hash|
+      result_hash["column_name"] == column_name
+    end
+    result && result["datetime_precision"]
+  end
+
+  def activerecord_column_option(tablename, column_name, option)
+    result = ActiveRecord::Base.connection.columns(tablename).find do |column|
+      column.name == column_name
+    end
+    result && result.send(option)
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb b/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb
new file mode 100644
index 0000000000..23817198b1
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb
@@ -0,0 +1,15 @@
+require 'cases/helper'
+
+class PostgresqlTypeLookupTest < ActiveRecord::TestCase
+  setup do
+    @connection = ActiveRecord::Base.connection
+  end
+
+  test "array delimiters are looked up correctly" do
+    box_array = @connection.type_map.lookup(1020)
+    int_array = @connection.type_map.lookup(1007)
+
+    assert_equal ';', box_array.delimiter
+    assert_equal ',', int_array.delimiter
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/utils_test.rb b/activerecord/test/cases/adapters/postgresql/utils_test.rb
new file mode 100644
index 0000000000..3fdb6888d9
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/utils_test.rb
@@ -0,0 +1,61 @@
+require 'cases/helper'
+
+class PostgreSQLUtilsTest < ActiveSupport::TestCase
+  Name = ActiveRecord::ConnectionAdapters::PostgreSQL::Name
+  include ActiveRecord::ConnectionAdapters::PostgreSQL::Utils
+
+  def test_extract_schema_qualified_name
+    {
+      %(table_name)            => [nil,'table_name'],
+      %("table.name")          => [nil,'table.name'],
+      %(schema.table_name)     => %w{schema table_name},
+      %("schema".table_name)   => %w{schema table_name},
+      %(schema."table_name")   => %w{schema table_name},
+      %("schema"."table_name") => %w{schema table_name},
+      %("even spaces".table)   => ['even spaces','table'],
+      %(schema."table.name")   => ['schema', 'table.name']
+    }.each do |given, expect|
+      assert_equal Name.new(*expect), extract_schema_qualified_name(given)
+    end
+  end
+end
+
+class PostgreSQLNameTest < ActiveSupport::TestCase
+  Name = ActiveRecord::ConnectionAdapters::PostgreSQL::Name
+
+  test "represents itself as schema.name" do
+    obj = Name.new("public", "articles")
+    assert_equal "public.articles", obj.to_s
+  end
+
+  test "without schema, represents itself as name only" do
+    obj = Name.new(nil, "articles")
+    assert_equal "articles", obj.to_s
+  end
+
+  test "quoted returns a string representation usable in a query" do
+    assert_equal %("articles"), Name.new(nil, "articles").quoted
+    assert_equal %("public"."articles"), Name.new("public", "articles").quoted
+  end
+
+  test "prevents double quoting" do
+    name = Name.new('"quoted_schema"', '"quoted_table"')
+    assert_equal "quoted_schema.quoted_table", name.to_s
+    assert_equal %("quoted_schema"."quoted_table"), name.quoted
+  end
+
+  test "equality based on state" do
+    assert_equal Name.new("access", "users"), Name.new("access", "users")
+    assert_equal Name.new(nil, "users"), Name.new(nil, "users")
+    assert_not_equal Name.new(nil, "users"), Name.new("access", "users")
+    assert_not_equal Name.new("access", "users"), Name.new("public", "users")
+    assert_not_equal Name.new("public", "users"), Name.new("public", "articles")
+  end
+
+  test "can be used as hash key" do
+    hash = {Name.new("schema", "article_seq") => "success"}
+    assert_equal "success", hash[Name.new("schema", "article_seq")]
+    assert_equal nil, hash[Name.new("schema", "articles")]
+    assert_equal nil, hash[Name.new("public", "article_seq")]
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/uuid_test.rb b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
new file mode 100644
index 0000000000..66006d718f
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
@@ -0,0 +1,256 @@
+# encoding: utf-8
+
+require "cases/helper"
+require 'active_record/base'
+require 'active_record/connection_adapters/postgresql_adapter'
+
+module PostgresqlUUIDHelper
+  def connection
+    @connection ||= ActiveRecord::Base.connection
+  end
+
+  def drop_table(name)
+    connection.execute "drop table if exists #{name}"
+  end
+end
+
+class PostgresqlUUIDTest < ActiveRecord::TestCase
+  include PostgresqlUUIDHelper
+
+  class UUIDType < ActiveRecord::Base
+    self.table_name = "uuid_data_type"
+  end
+
+  setup do
+    connection.create_table "uuid_data_type" do |t|
+      t.uuid 'guid'
+    end
+  end
+
+  teardown do
+    drop_table "uuid_data_type"
+  end
+
+  def test_change_column_default
+    @connection.add_column :uuid_data_type, :thingy, :uuid, null: false, default: "uuid_generate_v1()"
+    UUIDType.reset_column_information
+    column = UUIDType.columns_hash['thingy']
+    assert_equal "uuid_generate_v1()", column.default_function
+
+    @connection.change_column :uuid_data_type, :thingy, :uuid, null: false, default: "uuid_generate_v4()"
+
+    UUIDType.reset_column_information
+    column = UUIDType.columns_hash['thingy']
+    assert_equal "uuid_generate_v4()", column.default_function
+  ensure
+    UUIDType.reset_column_information
+  end
+
+  def test_data_type_of_uuid_types
+    column = UUIDType.columns_hash["guid"]
+    assert_equal :uuid, column.type
+    assert_equal "uuid", column.sql_type
+    assert_not column.number?
+    assert_not column.binary?
+    assert_not column.array
+  end
+
+  def test_treat_blank_uuid_as_nil
+    UUIDType.create! guid: ''
+    assert_equal(nil, UUIDType.last.guid)
+  end
+
+  def test_treat_invalid_uuid_as_nil
+    uuid = UUIDType.create! guid: 'foobar'
+    assert_equal(nil, uuid.guid)
+  end
+
+  def test_invalid_uuid_dont_modify_before_type_cast
+    uuid = UUIDType.new guid: 'foobar'
+    assert_equal 'foobar', uuid.guid_before_type_cast
+  end
+
+  def test_rfc_4122_regex
+    # Valid uuids
+    ['A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11',
+     '{a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11}',
+     'a0eebc999c0b4ef8bb6d6bb9bd380a11',
+     'a0ee-bc99-9c0b-4ef8-bb6d-6bb9-bd38-0a11',
+     '{a0eebc99-9c0b4ef8-bb6d6bb9-bd380a11}'].each do |valid_uuid|
+      uuid = UUIDType.new guid: valid_uuid
+      assert_not_nil uuid.guid
+    end
+
+    # Invalid uuids
+    [['A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11'],
+     Hash.new,
+     0,
+     0.0,
+     true,
+     'Z0000C99-9C0B-4EF8-BB6D-6BB9BD380A11',
+     '{a0eebc99-9c0b-4ef8-fb6d-6bb9bd380a11}',
+     'a0eebc999r0b4ef8ab6d6bb9bd380a11',
+     'a0ee-bc99------4ef8-bb6d-6bb9-bd38-0a11',
+     '{a0eebc99-bb6d6bb9-bd380a11}'].each do |invalid_uuid|
+      uuid = UUIDType.new guid: invalid_uuid
+      assert_nil uuid.guid
+    end
+  end
+
+  def test_uuid_formats
+    ["A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11",
+     "{a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11}",
+     "a0eebc999c0b4ef8bb6d6bb9bd380a11",
+     "a0ee-bc99-9c0b-4ef8-bb6d-6bb9-bd38-0a11",
+     "{a0eebc99-9c0b4ef8-bb6d6bb9-bd380a11}"].each do |valid_uuid|
+      UUIDType.create(guid: valid_uuid)
+      uuid = UUIDType.last
+      assert_equal "a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11", uuid.guid
+    end
+  end
+end
+
+class PostgresqlUUIDGenerationTest < ActiveRecord::TestCase
+  include PostgresqlUUIDHelper
+
+  class UUID < ActiveRecord::Base
+    self.table_name = 'pg_uuids'
+  end
+
+  setup do
+    enable_uuid_ossp!(connection)
+
+    connection.create_table('pg_uuids', id: :uuid, default: 'uuid_generate_v1()') do |t|
+      t.string 'name'
+      t.uuid 'other_uuid', default: 'uuid_generate_v4()'
+    end
+
+    # Create custom PostgreSQL function to generate UUIDs
+    # to test dumping tables which columns have defaults with custom functions
+    connection.execute <<-SQL
+    CREATE OR REPLACE FUNCTION my_uuid_generator() RETURNS uuid
+    AS $$ SELECT * FROM uuid_generate_v4() $$
+    LANGUAGE SQL VOLATILE;
+    SQL
+
+    # Create such a table with custom function as default value generator
+    connection.create_table('pg_uuids_2', id: :uuid, default: 'my_uuid_generator()') do |t|
+      t.string 'name'
+      t.uuid 'other_uuid_2', default: 'my_uuid_generator()'
+    end
+  end
+
+  teardown do
+    drop_table "pg_uuids"
+    drop_table 'pg_uuids_2'
+    connection.execute 'DROP FUNCTION IF EXISTS my_uuid_generator();'
+  end
+
+  if ActiveRecord::Base.connection.supports_extensions?
+    def test_id_is_uuid
+      assert_equal :uuid, UUID.columns_hash['id'].type
+      assert UUID.primary_key
+    end
+
+    def test_id_has_a_default
+      u = UUID.create
+      assert_not_nil u.id
+    end
+
+    def test_auto_create_uuid
+      u = UUID.create
+      u.reload
+      assert_not_nil u.other_uuid
+    end
+
+    def test_pk_and_sequence_for_uuid_primary_key
+      pk, seq = connection.pk_and_sequence_for('pg_uuids')
+      assert_equal 'id', pk
+      assert_equal nil, seq
+    end
+
+    def test_schema_dumper_for_uuid_primary_key
+      schema = StringIO.new
+      ActiveRecord::SchemaDumper.dump(connection, schema)
+      assert_match(/\bcreate_table "pg_uuids", id: :uuid, default: "uuid_generate_v1\(\)"/, schema.string)
+      assert_match(/t\.uuid   "other_uuid", default: "uuid_generate_v4\(\)"/, schema.string)
+    end
+
+    def test_schema_dumper_for_uuid_primary_key_with_custom_default
+      schema = StringIO.new
+      ActiveRecord::SchemaDumper.dump(connection, schema)
+      assert_match(/\bcreate_table "pg_uuids_2", id: :uuid, default: "my_uuid_generator\(\)"/, schema.string)
+      assert_match(/t\.uuid   "other_uuid_2", default: "my_uuid_generator\(\)"/, schema.string)
+    end
+  end
+end
+
+class PostgresqlUUIDTestNilDefault < ActiveRecord::TestCase
+  include PostgresqlUUIDHelper
+
+  setup do
+    enable_uuid_ossp!(connection)
+
+    connection.create_table('pg_uuids', id: false) do |t|
+      t.primary_key :id, :uuid, default: nil
+      t.string 'name'
+    end
+  end
+
+  teardown do
+    drop_table "pg_uuids"
+  end
+
+  if ActiveRecord::Base.connection.supports_extensions?
+    def test_id_allows_default_override_via_nil
+      col_desc = connection.execute("SELECT pg_get_expr(d.adbin, d.adrelid) as default
+                                    FROM pg_attribute a
+                                    LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum
+                                    WHERE a.attname='id' AND a.attrelid = 'pg_uuids'::regclass").first
+      assert_nil col_desc["default"]
+    end
+  end
+end
+
+class PostgresqlUUIDTestInverseOf < ActiveRecord::TestCase
+  include PostgresqlUUIDHelper
+
+  class UuidPost < ActiveRecord::Base
+    self.table_name = 'pg_uuid_posts'
+    has_many :uuid_comments, inverse_of: :uuid_post
+  end
+
+  class UuidComment < ActiveRecord::Base
+    self.table_name = 'pg_uuid_comments'
+    belongs_to :uuid_post
+  end
+
+  setup do
+    enable_uuid_ossp!(connection)
+
+    connection.transaction do
+      connection.create_table('pg_uuid_posts', id: :uuid) do |t|
+        t.string 'title'
+      end
+      connection.create_table('pg_uuid_comments', id: :uuid) do |t|
+        t.references :uuid_post, type: :uuid
+        t.string 'content'
+      end
+    end
+  end
+
+  teardown do
+    connection.transaction do
+      drop_table "pg_uuid_comments"
+      drop_table "pg_uuid_posts"
+    end
+  end
+
+  if ActiveRecord::Base.connection.supports_extensions?
+    def test_collection_association_with_uuid
+      post    = UuidPost.create!
+      comment = post.uuid_comments.create!
+      assert post.uuid_comments.find(comment.id)
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/view_test.rb b/activerecord/test/cases/adapters/postgresql/view_test.rb
new file mode 100644
index 0000000000..47b7d38eda
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/view_test.rb
@@ -0,0 +1,67 @@
+require "cases/helper"
+
+module ViewTestConcern
+  extend ActiveSupport::Concern
+
+  included do
+    self.use_transactional_fixtures = false
+    mattr_accessor :view_type
+  end
+
+  SCHEMA_NAME = 'test_schema'
+  TABLE_NAME = 'things'
+  COLUMNS = [
+    'id integer',
+    'name character varying(50)',
+    'email character varying(50)',
+    'moment timestamp without time zone'
+  ]
+
+  class ThingView < ActiveRecord::Base
+  end
+
+  def setup
+    super
+    ThingView.table_name = "#{SCHEMA_NAME}.#{view_type}_things"
+
+    @connection = ActiveRecord::Base.connection
+    @connection.execute "CREATE SCHEMA #{SCHEMA_NAME} CREATE TABLE #{TABLE_NAME} (#{COLUMNS.join(',')})"
+    @connection.execute "CREATE #{view_type.humanize} #{ThingView.table_name} AS SELECT * FROM #{SCHEMA_NAME}.#{TABLE_NAME}"
+  end
+
+  def teardown
+    super
+    @connection.execute "DROP SCHEMA #{SCHEMA_NAME} CASCADE"
+  end
+
+  def test_table_exists
+    name = ThingView.table_name
+    assert @connection.table_exists?(name), "'#{name}' table should exist"
+  end
+
+  def test_column_definitions
+    assert_nothing_raised do
+      assert_equal COLUMNS, columns(ThingView.table_name)
+    end
+  end
+
+  private
+    def columns(table_name)
+      @connection.send(:column_definitions, table_name).map do |name, type, default|
+        "#{name} #{type}" + (default ? " default #{default}" : '')
+      end
+    end
+
+end
+
+class ViewTest < ActiveRecord::TestCase
+  include ViewTestConcern
+  self.view_type = 'view'
+end
+
+if ActiveRecord::Base.connection.supports_materialized_views?
+  class MaterializedViewTest < ActiveRecord::TestCase
+    include ViewTestConcern
+    self.view_type = 'materialized_view'
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/xml_test.rb b/activerecord/test/cases/adapters/postgresql/xml_test.rb
new file mode 100644
index 0000000000..4165dd5ac9
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/xml_test.rb
@@ -0,0 +1,48 @@
+# encoding: utf-8
+require 'cases/helper'
+
+class PostgresqlXMLTest < ActiveRecord::TestCase
+  class XmlDataType < ActiveRecord::Base
+    self.table_name = 'xml_data_type'
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    begin
+      @connection.transaction do
+        @connection.create_table('xml_data_type') do |t|
+          t.xml 'payload'
+        end
+      end
+    rescue ActiveRecord::StatementInvalid
+      skip "do not test on PG without xml"
+    end
+    @column = XmlDataType.columns_hash['payload']
+  end
+
+  teardown do
+    @connection.execute 'drop table if exists xml_data_type'
+  end
+
+  def test_column
+    assert_equal :xml, @column.type
+  end
+
+  def test_null_xml
+    @connection.execute %q|insert into xml_data_type (payload) VALUES(null)|
+    assert_nil XmlDataType.first.payload
+  end
+
+  def test_round_trip
+    data = XmlDataType.new(payload: "<foo>bar</foo>")
+    assert_equal "<foo>bar</foo>", data.payload
+    data.save!
+    assert_equal "<foo>bar</foo>", data.reload.payload
+  end
+
+  def test_update_all
+    data = XmlDataType.create!
+    XmlDataType.update_all(payload: "<bar>baz</bar>")
+    assert_equal "<bar>baz</bar>", data.reload.payload
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb b/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb
new file mode 100644
index 0000000000..13b754d226
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb
@@ -0,0 +1,98 @@
+require "cases/helper"
+
+class CopyTableTest < ActiveRecord::TestCase
+  fixtures :customers
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    class << @connection
+      public :copy_table, :table_structure, :indexes
+    end
+  end
+
+  def test_copy_table(from = 'customers', to = 'customers2', options = {})
+    assert_nothing_raised {copy_table(from, to, options)}
+    assert_equal row_count(from), row_count(to)
+
+    if block_given?
+      yield from, to, options
+    else
+      assert_equal column_names(from), column_names(to)
+    end
+
+    @connection.drop_table(to) rescue nil
+  end
+
+  def test_copy_table_renaming_column
+    test_copy_table('customers', 'customers2',
+        :rename => {'name' => 'person_name'}) do |from, to, options|
+      expected = column_values(from, 'name')
+      assert_equal expected, column_values(to, 'person_name')
+      assert expected.any?, "No values in table: #{expected.inspect}"
+    end
+  end
+
+  def test_copy_table_allows_to_pass_options_to_create_table
+    @connection.create_table('blocker_table')
+    test_copy_table('customers', 'blocker_table', force: true)
+  end
+
+  def test_copy_table_with_index
+    test_copy_table('comments', 'comments_with_index') do
+      @connection.add_index('comments_with_index', ['post_id', 'type'])
+      test_copy_table('comments_with_index', 'comments_with_index2') do
+        assert_equal table_indexes_without_name('comments_with_index'),
+                     table_indexes_without_name('comments_with_index2')
+      end
+    end
+  end
+
+  def test_copy_table_without_primary_key
+    test_copy_table('developers_projects', 'programmers_projects') do
+      assert_nil @connection.primary_key('programmers_projects')
+    end
+  end
+
+  def test_copy_table_with_id_col_that_is_not_primary_key
+    test_copy_table('goofy_string_id', 'goofy_string_id2') do
+      original_id = @connection.columns('goofy_string_id').detect{|col| col.name == 'id' }
+      copied_id = @connection.columns('goofy_string_id2').detect{|col| col.name == 'id' }
+      assert_equal original_id.type, copied_id.type
+      assert_equal original_id.sql_type, copied_id.sql_type
+      assert_equal original_id.limit, copied_id.limit
+    end
+  end
+
+  def test_copy_table_with_unconventional_primary_key
+    test_copy_table('owners', 'owners_unconventional') do
+      original_pk = @connection.primary_key('owners')
+      copied_pk = @connection.primary_key('owners_unconventional')
+      assert_equal original_pk, copied_pk
+    end
+  end
+
+  def test_copy_table_with_binary_column
+    test_copy_table 'binaries', 'binaries2'
+  end
+
+protected
+  def copy_table(from, to, options = {})
+    @connection.copy_table(from, to, {:temporary => true}.merge(options))
+  end
+
+  def column_names(table)
+    @connection.table_structure(table).map {|column| column['name']}
+  end
+
+  def column_values(table, column)
+    @connection.select_all("SELECT #{column} FROM #{table} ORDER BY id").map {|row| row[column]}
+  end
+
+  def table_indexes_without_name(table)
+    @connection.indexes(table).delete(:name)
+  end
+
+  def row_count(table)
+    @connection.select_one("SELECT COUNT(*) AS count FROM #{table}")['count']
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/explain_test.rb b/activerecord/test/cases/adapters/sqlite3/explain_test.rb
new file mode 100644
index 0000000000..f1d6119d2e
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/explain_test.rb
@@ -0,0 +1,26 @@
+require "cases/helper"
+require 'models/developer'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SQLite3Adapter
+      class ExplainTest < ActiveRecord::TestCase
+        fixtures :developers
+
+        def test_explain_for_one_query
+          explain = Developer.where(:id => 1).explain
+          assert_match %(EXPLAIN for: SELECT "developers".* FROM "developers" WHERE "developers"."id" = ?), explain
+          assert_match(/(SEARCH )?TABLE developers USING (INTEGER )?PRIMARY KEY/, explain)
+        end
+
+        def test_explain_with_eager_loading
+          explain = Developer.where(:id => 1).includes(:audit_logs).explain
+          assert_match %(EXPLAIN for: SELECT "developers".* FROM "developers" WHERE "developers"."id" = ?), explain
+          assert_match(/(SEARCH )?TABLE developers USING (INTEGER )?PRIMARY KEY/, explain)
+          assert_match %(EXPLAIN for: SELECT "audit_logs".* FROM "audit_logs" WHERE "audit_logs"."developer_id" IN (1)), explain
+          assert_match(/(SCAN )?TABLE audit_logs/, explain)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/quoting_test.rb b/activerecord/test/cases/adapters/sqlite3/quoting_test.rb
new file mode 100644
index 0000000000..ac8332e2fa
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/quoting_test.rb
@@ -0,0 +1,116 @@
+require "cases/helper"
+require 'bigdecimal'
+require 'yaml'
+require 'securerandom'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SQLite3Adapter
+      class QuotingTest < ActiveRecord::TestCase
+        def setup
+          @conn = Base.sqlite3_connection :database => ':memory:',
+            :adapter => 'sqlite3',
+            :timeout => 100
+        end
+
+        def test_type_cast_binary_encoding_without_logger
+          @conn.extend(Module.new { def logger; end })
+          column = Column.new(nil, nil, Type::String.new)
+          binary = SecureRandom.hex
+          expected = binary.dup.encode!(Encoding::UTF_8)
+          assert_equal expected, @conn.type_cast(binary, column)
+        end
+
+        def test_type_cast_symbol
+          assert_equal 'foo', @conn.type_cast(:foo, nil)
+        end
+
+        def test_type_cast_date
+          date = Date.today
+          expected = @conn.quoted_date(date)
+          assert_equal expected, @conn.type_cast(date, nil)
+        end
+
+        def test_type_cast_time
+          time = Time.now
+          expected = @conn.quoted_date(time)
+          assert_equal expected, @conn.type_cast(time, nil)
+        end
+
+        def test_type_cast_numeric
+          assert_equal 10, @conn.type_cast(10, nil)
+          assert_equal 2.2, @conn.type_cast(2.2, nil)
+        end
+
+        def test_type_cast_nil
+          assert_equal nil, @conn.type_cast(nil, nil)
+        end
+
+        def test_type_cast_true
+          c = Column.new(nil, 1, Type::Integer.new)
+          assert_equal 't', @conn.type_cast(true, nil)
+          assert_equal 1, @conn.type_cast(true, c)
+        end
+
+        def test_type_cast_false
+          c = Column.new(nil, 1, Type::Integer.new)
+          assert_equal 'f', @conn.type_cast(false, nil)
+          assert_equal 0, @conn.type_cast(false, c)
+        end
+
+        def test_type_cast_string
+          assert_equal '10', @conn.type_cast('10', nil)
+
+          c = Column.new(nil, 1, Type::Integer.new)
+          assert_equal 10, @conn.type_cast('10', c)
+
+          c = Column.new(nil, 1, Type::Float.new)
+          assert_equal 10.1, @conn.type_cast('10.1', c)
+
+          c = Column.new(nil, 1, Type::Binary.new)
+          assert_equal '10.1', @conn.type_cast('10.1', c)
+
+          c = Column.new(nil, 1, Type::Date.new)
+          assert_equal '10.1', @conn.type_cast('10.1', c)
+        end
+
+        def test_type_cast_bigdecimal
+          bd = BigDecimal.new '10.0'
+          assert_equal bd.to_f, @conn.type_cast(bd, nil)
+        end
+
+        def test_type_cast_unknown_should_raise_error
+          obj = Class.new.new
+          assert_raise(TypeError) { @conn.type_cast(obj, nil) }
+        end
+
+        def test_type_cast_object_which_responds_to_quoted_id
+          quoted_id_obj = Class.new {
+            def quoted_id
+              "'zomg'"
+            end
+
+            def id
+              10
+            end
+          }.new
+          assert_equal 10, @conn.type_cast(quoted_id_obj, nil)
+
+          quoted_id_obj = Class.new {
+            def quoted_id
+              "'zomg'"
+            end
+          }.new
+          assert_raise(TypeError) { @conn.type_cast(quoted_id_obj, nil) }
+        end
+
+        def test_quoting_binary_strings
+          value = "hello".encode('ascii-8bit')
+          column = Column.new(nil, 1, SQLite3String.new)
+
+          assert_equal "'hello'", @conn.quote(value, column)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
new file mode 100644
index 0000000000..b2bf9480dd
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -0,0 +1,455 @@
+# encoding: utf-8
+require "cases/helper"
+require 'models/owner'
+require 'tempfile'
+require 'support/ddl_helper'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SQLite3AdapterTest < ActiveRecord::TestCase
+      include DdlHelper
+
+      self.use_transactional_fixtures = false
+
+      class DualEncoding < ActiveRecord::Base
+      end
+
+      def setup
+        @conn = Base.sqlite3_connection database: ':memory:',
+                                        adapter: 'sqlite3',
+                                        timeout: 100
+      end
+
+      def test_bad_connection
+        assert_raise ActiveRecord::NoDatabaseError do
+          connection = ActiveRecord::Base.sqlite3_connection(adapter: "sqlite3", database: "/tmp/should/_not/_exist/-cinco-dog.db")
+          connection.exec_query('drop table if exists ex')
+        end
+      end
+
+      unless in_memory_db?
+        def test_connect_with_url
+          original_connection = ActiveRecord::Base.remove_connection
+          tf = Tempfile.open 'whatever'
+          url = "sqlite3:#{tf.path}"
+          ActiveRecord::Base.establish_connection(url)
+          assert ActiveRecord::Base.connection
+        ensure
+          tf.close
+          tf.unlink
+          ActiveRecord::Base.establish_connection(original_connection)
+        end
+
+        def test_connect_memory_with_url
+          original_connection = ActiveRecord::Base.remove_connection
+          url = "sqlite3::memory:"
+          ActiveRecord::Base.establish_connection(url)
+          assert ActiveRecord::Base.connection
+        ensure
+          ActiveRecord::Base.establish_connection(original_connection)
+        end
+      end
+
+      def test_valid_column
+        with_example_table do
+          column = @conn.columns('ex').find { |col| col.name == 'id' }
+          assert @conn.valid_type?(column.type)
+        end
+      end
+
+      # sqlite3 databases should be able to support any type and not just the
+      # ones mentioned in the native_database_types.
+      #
+      # Therefore test_invalid column should always return true even if the
+      # type is not valid.
+      def test_invalid_column
+        assert @conn.valid_type?(:foobar)
+      end
+
+      def test_column_types
+        owner = Owner.create!(name: "hello".encode('ascii-8bit'))
+        owner.reload
+        select = Owner.columns.map { |c| "typeof(#{c.name})" }.join ', '
+        result = Owner.connection.exec_query <<-esql
+          SELECT #{select}
+          FROM   #{Owner.table_name}
+          WHERE  #{Owner.primary_key} = #{owner.id}
+        esql
+
+        assert(!result.rows.first.include?("blob"), "should not store blobs")
+      ensure
+        owner.delete
+      end
+
+      def test_exec_insert
+        with_example_table do
+          column = @conn.columns('ex').find { |col| col.name == 'number' }
+          vals   = [[column, 10]]
+          @conn.exec_insert('insert into ex (number) VALUES (?)', 'SQL', vals)
+
+          result = @conn.exec_query(
+            'select number from ex where number = ?', 'SQL', vals)
+
+          assert_equal 1, result.rows.length
+          assert_equal 10, result.rows.first.first
+        end
+      end
+
+      def test_primary_key_returns_nil_for_no_pk
+        with_example_table 'id int, data string' do
+          assert_nil @conn.primary_key('ex')
+        end
+      end
+
+      def test_connection_no_db
+        assert_raises(ArgumentError) do
+          Base.sqlite3_connection {}
+        end
+      end
+
+      def test_bad_timeout
+        assert_raises(TypeError) do
+          Base.sqlite3_connection database: ':memory:',
+                                  adapter: 'sqlite3',
+                                  timeout: 'usa'
+        end
+      end
+
+      # connection is OK with a nil timeout
+      def test_nil_timeout
+        conn = Base.sqlite3_connection database: ':memory:',
+                                       adapter: 'sqlite3',
+                                       timeout: nil
+        assert conn, 'made a connection'
+      end
+
+      def test_connect
+        assert @conn, 'should have connection'
+      end
+
+      # sqlite3 defaults to UTF-8 encoding
+      def test_encoding
+        assert_equal 'UTF-8', @conn.encoding
+      end
+
+      def test_bind_value_substitute
+        bind_param = @conn.substitute_at('foo', 0)
+        assert_equal Arel.sql('?'), bind_param
+      end
+
+      def test_exec_no_binds
+        with_example_table 'id int, data string' do
+          result = @conn.exec_query('SELECT id, data FROM ex')
+          assert_equal 0, result.rows.length
+          assert_equal 2, result.columns.length
+          assert_equal %w{ id data }, result.columns
+
+          @conn.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+          result = @conn.exec_query('SELECT id, data FROM ex')
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [[1, 'foo']], result.rows
+        end
+      end
+
+      def test_exec_query_with_binds
+        with_example_table 'id int, data string' do
+          @conn.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+          result = @conn.exec_query(
+            'SELECT id, data FROM ex WHERE id = ?', nil, [[nil, 1]])
+
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [[1, 'foo']], result.rows
+        end
+      end
+
+      def test_exec_query_typecasts_bind_vals
+        with_example_table 'id int, data string' do
+          @conn.exec_query('INSERT INTO ex (id, data) VALUES (1, "foo")')
+          column = @conn.columns('ex').find { |col| col.name == 'id' }
+
+          result = @conn.exec_query(
+            'SELECT id, data FROM ex WHERE id = ?', nil, [[column, '1-fuu']])
+
+          assert_equal 1, result.rows.length
+          assert_equal 2, result.columns.length
+
+          assert_equal [[1, 'foo']], result.rows
+        end
+      end
+
+      def test_quote_binary_column_escapes_it
+        DualEncoding.connection.execute(<<-eosql)
+          CREATE TABLE IF NOT EXISTS dual_encodings (
+            id integer PRIMARY KEY AUTOINCREMENT,
+            name varchar(255),
+            data binary
+          )
+        eosql
+        str = "\x80".force_encoding("ASCII-8BIT")
+        binary = DualEncoding.new name: 'いただきます！', data: str
+        binary.save!
+        assert_equal str, binary.data
+      ensure
+        DualEncoding.connection.execute('DROP TABLE IF EXISTS dual_encodings')
+      end
+
+      def test_type_cast_should_not_mutate_encoding
+        name  = 'hello'.force_encoding(Encoding::ASCII_8BIT)
+        Owner.create(name: name)
+        assert_equal Encoding::ASCII_8BIT, name.encoding
+      ensure
+        Owner.delete_all
+      end
+
+      def test_execute
+        with_example_table do
+          @conn.execute "INSERT INTO ex (number) VALUES (10)"
+          records = @conn.execute "SELECT * FROM ex"
+          assert_equal 1, records.length
+
+          record = records.first
+          assert_equal 10, record['number']
+          assert_equal 1, record['id']
+        end
+      end
+
+      def test_quote_string
+        assert_equal "''", @conn.quote_string("'")
+      end
+
+      def test_insert_sql
+        with_example_table do
+          2.times do |i|
+            rv = @conn.insert_sql "INSERT INTO ex (number) VALUES (#{i})"
+            assert_equal(i + 1, rv)
+          end
+
+          records = @conn.execute "SELECT * FROM ex"
+          assert_equal 2, records.length
+        end
+      end
+
+      def test_insert_sql_logged
+        with_example_table do
+          sql = "INSERT INTO ex (number) VALUES (10)"
+          name = "foo"
+          assert_logged [[sql, name, []]] do
+            @conn.insert_sql sql, name
+          end
+        end
+      end
+
+      def test_insert_id_value_returned
+        with_example_table do
+          sql = "INSERT INTO ex (number) VALUES (10)"
+          idval = 'vuvuzela'
+          id = @conn.insert_sql sql, nil, nil, idval
+          assert_equal idval, id
+        end
+      end
+
+      def test_select_rows
+        with_example_table do
+          2.times do |i|
+            @conn.create "INSERT INTO ex (number) VALUES (#{i})"
+          end
+          rows = @conn.select_rows 'select number, id from ex'
+          assert_equal [[0, 1], [1, 2]], rows
+        end
+      end
+
+      def test_select_rows_logged
+        with_example_table do
+          sql = "select * from ex"
+          name = "foo"
+          assert_logged [[sql, name, []]] do
+            @conn.select_rows sql, name
+          end
+        end
+      end
+
+      def test_transaction
+        with_example_table do
+          count_sql = 'select count(*) from ex'
+
+          @conn.begin_db_transaction
+          @conn.create "INSERT INTO ex (number) VALUES (10)"
+
+          assert_equal 1, @conn.select_rows(count_sql).first.first
+          @conn.rollback_db_transaction
+          assert_equal 0, @conn.select_rows(count_sql).first.first
+        end
+      end
+
+      def test_tables
+        with_example_table do
+          assert_equal %w{ ex }, @conn.tables
+          with_example_table 'id integer PRIMARY KEY AUTOINCREMENT, number integer', 'people' do
+            assert_equal %w{ ex people }.sort, @conn.tables.sort
+          end
+        end
+      end
+
+      def test_tables_logs_name
+        sql = <<-SQL
+          SELECT name FROM sqlite_master
+          WHERE type = 'table' AND NOT name = 'sqlite_sequence'
+        SQL
+        assert_logged [[sql.squish, 'SCHEMA', []]] do
+          @conn.tables('hello')
+        end
+      end
+
+      def test_indexes_logs_name
+        with_example_table do
+          assert_logged [["PRAGMA index_list(\"ex\")", 'SCHEMA', []]] do
+            @conn.indexes('ex', 'hello')
+          end
+        end
+      end
+
+      def test_table_exists_logs_name
+        with_example_table do
+          sql = <<-SQL
+            SELECT name FROM sqlite_master
+            WHERE type = 'table'
+            AND NOT name = 'sqlite_sequence' AND name = \"ex\"
+          SQL
+          assert_logged [[sql.squish, 'SCHEMA', []]] do
+            assert @conn.table_exists?('ex')
+          end
+        end
+      end
+
+      def test_columns
+        with_example_table do
+          columns = @conn.columns('ex').sort_by { |x| x.name }
+          assert_equal 2, columns.length
+          assert_equal %w{ id number }.sort, columns.map { |x| x.name }
+          assert_equal [nil, nil], columns.map { |x| x.default }
+          assert_equal [true, true], columns.map { |x| x.null }
+        end
+      end
+
+      def test_columns_with_default
+        with_example_table 'id integer PRIMARY KEY AUTOINCREMENT, number integer default 10' do
+          column = @conn.columns('ex').find { |x|
+            x.name == 'number'
+          }
+          assert_equal '10', column.default
+        end
+      end
+
+      def test_columns_with_not_null
+        with_example_table 'id integer PRIMARY KEY AUTOINCREMENT, number integer not null' do
+          column = @conn.columns('ex').find { |x| x.name == 'number' }
+          assert_not column.null, "column should not be null"
+        end
+      end
+
+      def test_indexes_logs
+        with_example_table do
+          assert_logged [["PRAGMA index_list(\"ex\")", "SCHEMA", []]] do
+            @conn.indexes('ex')
+          end
+        end
+      end
+
+      def test_no_indexes
+        assert_equal [], @conn.indexes('items')
+      end
+
+      def test_index
+        with_example_table do
+          @conn.add_index 'ex', 'id', unique: true, name: 'fun'
+          index = @conn.indexes('ex').find { |idx| idx.name == 'fun' }
+
+          assert_equal 'ex', index.table
+          assert index.unique, 'index is unique'
+          assert_equal ['id'], index.columns
+        end
+      end
+
+      def test_non_unique_index
+        with_example_table do
+          @conn.add_index 'ex', 'id', name: 'fun'
+          index = @conn.indexes('ex').find { |idx| idx.name == 'fun' }
+          assert_not index.unique, 'index is not unique'
+        end
+      end
+
+      def test_compound_index
+        with_example_table do
+          @conn.add_index 'ex', %w{ id number }, name: 'fun'
+          index = @conn.indexes('ex').find { |idx| idx.name == 'fun' }
+          assert_equal %w{ id number }.sort, index.columns.sort
+        end
+      end
+
+      def test_primary_key
+        with_example_table do
+          assert_equal 'id', @conn.primary_key('ex')
+          with_example_table 'internet integer PRIMARY KEY AUTOINCREMENT, number integer not null', 'foos' do
+            assert_equal 'internet', @conn.primary_key('foos')
+          end
+        end
+      end
+
+      def test_no_primary_key
+        with_example_table 'number integer not null' do
+          assert_nil @conn.primary_key('ex')
+        end
+      end
+
+      def test_supports_extensions
+        assert_not @conn.supports_extensions?, 'does not support extensions'
+      end
+
+      def test_respond_to_enable_extension
+        assert @conn.respond_to?(:enable_extension)
+      end
+
+      def test_respond_to_disable_extension
+        assert @conn.respond_to?(:disable_extension)
+      end
+
+      def test_statement_closed
+        db = SQLite3::Database.new(ActiveRecord::Base.
+                                   configurations['arunit']['database'])
+        statement = SQLite3::Statement.new(db,
+                                           'CREATE TABLE statement_test (number integer not null)')
+        statement.stubs(:step).raises(SQLite3::BusyException, 'busy')
+        statement.stubs(:columns).once.returns([])
+        statement.expects(:close).once
+        SQLite3::Statement.stubs(:new).returns(statement)
+
+        assert_raises ActiveRecord::StatementInvalid do
+          @conn.exec_query 'select * from statement_test'
+        end
+      end
+
+      private
+
+      def assert_logged logs
+        subscriber = SQLSubscriber.new
+        subscription = ActiveSupport::Notifications.subscribe('sql.active_record', subscriber)
+        yield
+        assert_equal logs, subscriber.logged
+      ensure
+        ActiveSupport::Notifications.unsubscribe(subscription)
+      end
+
+      def with_example_table(definition = nil, table_name = 'ex', &block)
+        definition ||= <<-SQL
+          id integer PRIMARY KEY AUTOINCREMENT,
+          number integer
+        SQL
+        super(@conn, table_name, definition, &block)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb
new file mode 100644
index 0000000000..f545fc2011
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb
@@ -0,0 +1,21 @@
+# encoding: utf-8
+require "cases/helper"
+require 'models/owner'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SQLite3CreateFolder < ActiveRecord::TestCase
+      def test_sqlite_creates_directory
+        Dir.mktmpdir do |dir|
+          dir = Pathname.new(dir)
+          @conn = Base.sqlite3_connection :database => dir.join("db/foo.sqlite3"),
+                               :adapter => 'sqlite3',
+                               :timeout => 100
+
+          assert Dir.exist? dir.join('db')
+          assert File.exist? dir.join('db/foo.sqlite3')
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb b/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb
new file mode 100644
index 0000000000..fd0044ac05
--- /dev/null
+++ b/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb
@@ -0,0 +1,25 @@
+require 'cases/helper'
+
+module ActiveRecord::ConnectionAdapters
+  class SQLite3Adapter
+    class StatementPoolTest < ActiveRecord::TestCase
+      if Process.respond_to?(:fork)
+        def test_cache_is_per_pid
+
+          cache = StatementPool.new nil, 10
+          cache['foo'] = 'bar'
+          assert_equal 'bar', cache['foo']
+
+          pid = fork {
+            lookup = cache['foo'];
+            exit!(!lookup)
+          }
+
+          Process.waitpid pid
+          assert $?.success?, 'process should exit successfully'
+        end
+      end
+    end
+  end
+end
+
diff --git a/activerecord/test/cases/aggregations_test.rb b/activerecord/test/cases/aggregations_test.rb
new file mode 100644
index 0000000000..5536702f58
--- /dev/null
+++ b/activerecord/test/cases/aggregations_test.rb
@@ -0,0 +1,158 @@
+require "cases/helper"
+require 'models/customer'
+
+class AggregationsTest < ActiveRecord::TestCase
+  fixtures :customers
+
+  def test_find_single_value_object
+    assert_equal 50, customers(:david).balance.amount
+    assert_kind_of Money, customers(:david).balance
+    assert_equal 300, customers(:david).balance.exchange_to("DKK").amount
+  end
+
+  def test_find_multiple_value_object
+    assert_equal customers(:david).address_street, customers(:david).address.street
+    assert(
+      customers(:david).address.close_to?(Address.new("Different Street", customers(:david).address_city, customers(:david).address_country))
+    )
+  end
+
+  def test_change_single_value_object
+    customers(:david).balance = Money.new(100)
+    customers(:david).save
+    assert_equal 100, customers(:david).reload.balance.amount
+  end
+
+  def test_immutable_value_objects
+    customers(:david).balance = Money.new(100)
+    assert_raise(RuntimeError) { customers(:david).balance.instance_eval { @amount = 20 } }
+  end
+
+  def test_inferred_mapping
+    assert_equal "35.544623640962634", customers(:david).gps_location.latitude
+    assert_equal "-105.9309951055148", customers(:david).gps_location.longitude
+
+    customers(:david).gps_location = GpsLocation.new("39x-110")
+
+    assert_equal "39", customers(:david).gps_location.latitude
+    assert_equal "-110", customers(:david).gps_location.longitude
+
+    customers(:david).save
+
+    customers(:david).reload
+
+    assert_equal "39", customers(:david).gps_location.latitude
+    assert_equal "-110", customers(:david).gps_location.longitude
+  end
+
+  def test_reloaded_instance_refreshes_aggregations
+    assert_equal "35.544623640962634", customers(:david).gps_location.latitude
+    assert_equal "-105.9309951055148", customers(:david).gps_location.longitude
+
+    Customer.update_all("gps_location = '24x113'")
+    customers(:david).reload
+    assert_equal '24x113', customers(:david)['gps_location']
+
+    assert_equal GpsLocation.new('24x113'), customers(:david).gps_location
+  end
+
+  def test_gps_equality
+    assert_equal GpsLocation.new('39x110'), GpsLocation.new('39x110')
+  end
+
+  def test_gps_inequality
+    assert_not_equal GpsLocation.new('39x110'), GpsLocation.new('39x111')
+  end
+
+  def test_allow_nil_gps_is_nil
+    assert_nil customers(:zaphod).gps_location
+  end
+
+  def test_allow_nil_gps_set_to_nil
+    customers(:david).gps_location = nil
+    customers(:david).save
+    customers(:david).reload
+    assert_nil customers(:david).gps_location
+  end
+
+  def test_allow_nil_set_address_attributes_to_nil
+    customers(:zaphod).address = nil
+    assert_nil customers(:zaphod).attributes[:address_street]
+    assert_nil customers(:zaphod).attributes[:address_city]
+    assert_nil customers(:zaphod).attributes[:address_country]
+  end
+
+  def test_allow_nil_address_set_to_nil
+    customers(:zaphod).address = nil
+    customers(:zaphod).save
+    customers(:zaphod).reload
+    assert_nil customers(:zaphod).address
+  end
+
+  def test_nil_raises_error_when_allow_nil_is_false
+    assert_raise(NoMethodError) { customers(:david).balance = nil }
+  end
+
+  def test_allow_nil_address_loaded_when_only_some_attributes_are_nil
+    customers(:zaphod).address_street = nil
+    customers(:zaphod).save
+    customers(:zaphod).reload
+    assert_kind_of Address, customers(:zaphod).address
+    assert_nil customers(:zaphod).address.street
+  end
+
+  def test_nil_assignment_results_in_nil
+    customers(:david).gps_location = GpsLocation.new('39x111')
+    assert_not_nil customers(:david).gps_location
+    customers(:david).gps_location = nil
+    assert_nil customers(:david).gps_location
+  end
+
+  def test_nil_return_from_converter_is_respected_when_allow_nil_is_true
+    customers(:david).non_blank_gps_location = ""
+    customers(:david).save
+    customers(:david).reload
+    assert_nil customers(:david).non_blank_gps_location
+  ensure
+    Customer.gps_conversion_was_run = nil
+  end
+
+  def test_nil_return_from_converter_results_in_failure_when_allow_nil_is_false
+    assert_raises(NoMethodError) do
+      customers(:barney).gps_location = ""
+    end
+  end
+
+  def test_do_not_run_the_converter_when_nil_was_set
+    customers(:david).non_blank_gps_location = nil
+    assert_nil Customer.gps_conversion_was_run
+  end
+
+  def test_custom_constructor
+    assert_equal 'Barney GUMBLE', customers(:barney).fullname.to_s
+    assert_kind_of Fullname, customers(:barney).fullname
+  end
+
+  def test_custom_converter
+    customers(:barney).fullname = 'Barnoit Gumbleau'
+    assert_equal 'Barnoit GUMBLEAU', customers(:barney).fullname.to_s
+    assert_kind_of Fullname, customers(:barney).fullname
+  end
+end
+
+class OverridingAggregationsTest < ActiveRecord::TestCase
+  class DifferentName; end
+
+  class Person < ActiveRecord::Base
+    composed_of :composed_of, :mapping => %w(person_first_name first_name)
+  end
+
+  class DifferentPerson < Person
+    composed_of :composed_of, :class_name => 'DifferentName', :mapping => %w(different_person_first_name first_name)
+  end
+
+  def test_composed_of_aggregation_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal Person.reflect_on_aggregation(:composed_of),
+                     DifferentPerson.reflect_on_aggregation(:composed_of)
+  end
+end
diff --git a/activerecord/test/cases/ar_schema_test.rb b/activerecord/test/cases/ar_schema_test.rb
new file mode 100644
index 0000000000..8700b20dee
--- /dev/null
+++ b/activerecord/test/cases/ar_schema_test.rb
@@ -0,0 +1,92 @@
+require "cases/helper"
+
+if ActiveRecord::Base.connection.supports_migrations?
+
+  class ActiveRecordSchemaTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    def setup
+      @connection = ActiveRecord::Base.connection
+      ActiveRecord::SchemaMigration.drop_table
+    end
+
+    teardown do
+      @connection.drop_table :fruits rescue nil
+      @connection.drop_table :nep_fruits rescue nil
+      @connection.drop_table :nep_schema_migrations rescue nil
+      ActiveRecord::SchemaMigration.delete_all rescue nil
+    end
+
+    def test_has_no_primary_key
+      old_primary_key_prefix_type = ActiveRecord::Base.primary_key_prefix_type
+      ActiveRecord::Base.primary_key_prefix_type = :table_name_with_underscore
+      assert_nil ActiveRecord::SchemaMigration.primary_key
+
+      ActiveRecord::SchemaMigration.create_table
+      assert_difference "ActiveRecord::SchemaMigration.count", 1 do
+        ActiveRecord::SchemaMigration.create version: 12
+      end
+    ensure
+      ActiveRecord::SchemaMigration.drop_table
+      ActiveRecord::Base.primary_key_prefix_type = old_primary_key_prefix_type
+    end
+
+    def test_schema_define
+      ActiveRecord::Schema.define(:version => 7) do
+        create_table :fruits do |t|
+          t.column :color, :string
+          t.column :fruit_size, :string  # NOTE: "size" is reserved in Oracle
+          t.column :texture, :string
+          t.column :flavor, :string
+        end
+      end
+
+      assert_nothing_raised { @connection.select_all "SELECT * FROM fruits" }
+      assert_nothing_raised { @connection.select_all "SELECT * FROM schema_migrations" }
+      assert_equal 7, ActiveRecord::Migrator::current_version
+    end
+
+    def test_schema_define_w_table_name_prefix
+      table_name = ActiveRecord::SchemaMigration.table_name
+      old_table_name_prefix = ActiveRecord::Base.table_name_prefix
+      ActiveRecord::Base.table_name_prefix  = "nep_"
+      ActiveRecord::SchemaMigration.table_name = "nep_#{table_name}"
+      ActiveRecord::Schema.define(:version => 7) do
+        create_table :fruits do |t|
+          t.column :color, :string
+          t.column :fruit_size, :string  # NOTE: "size" is reserved in Oracle
+          t.column :texture, :string
+          t.column :flavor, :string
+        end
+      end
+      assert_equal 7, ActiveRecord::Migrator::current_version
+    ensure
+      ActiveRecord::Base.table_name_prefix  = old_table_name_prefix
+      ActiveRecord::SchemaMigration.table_name = table_name
+    end
+
+    def test_schema_raises_an_error_for_invalid_column_type
+      assert_raise NoMethodError do
+        ActiveRecord::Schema.define(:version => 8) do
+          create_table :vegetables do |t|
+            t.unknown :color
+          end
+        end
+      end
+    end
+
+    def test_schema_subclass
+      Class.new(ActiveRecord::Schema).define(:version => 9) do
+        create_table :fruits
+      end
+      assert_nothing_raised { @connection.select_all "SELECT * FROM fruits" }
+    end
+
+    def test_normalize_version
+      assert_equal "118", ActiveRecord::SchemaMigration.normalize_migration_number("0000118")
+      assert_equal "002", ActiveRecord::SchemaMigration.normalize_migration_number("2")
+      assert_equal "017", ActiveRecord::SchemaMigration.normalize_migration_number("0017")
+      assert_equal "20131219224947", ActiveRecord::SchemaMigration.normalize_migration_number("20131219224947")
+    end
+  end
+end
diff --git a/activerecord/test/cases/associations/association_scope_test.rb b/activerecord/test/cases/associations/association_scope_test.rb
new file mode 100644
index 0000000000..3e0032ec73
--- /dev/null
+++ b/activerecord/test/cases/associations/association_scope_test.rb
@@ -0,0 +1,21 @@
+require 'cases/helper'
+require 'models/post'
+require 'models/author'
+
+module ActiveRecord
+  module Associations
+    class AssociationScopeTest < ActiveRecord::TestCase
+      test 'does not duplicate conditions' do
+        scope = AssociationScope.scope(Author.new.association(:welcome_posts),
+                                        Author.connection)
+        wheres = scope.where_values.map(&:right)
+        binds = scope.bind_values.map(&:last)
+        wheres = scope.where_values.map(&:right).reject { |node|
+          Arel::Nodes::BindParam === node
+        }
+        assert_equal wheres.uniq, wheres
+        assert_equal binds.uniq, binds
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/associations/belongs_to_associations_test.rb b/activerecord/test/cases/associations/belongs_to_associations_test.rb
new file mode 100644
index 0000000000..25555bd75c
--- /dev/null
+++ b/activerecord/test/cases/associations/belongs_to_associations_test.rb
@@ -0,0 +1,948 @@
+require 'cases/helper'
+require 'models/developer'
+require 'models/project'
+require 'models/company'
+require 'models/topic'
+require 'models/reply'
+require 'models/computer'
+require 'models/post'
+require 'models/author'
+require 'models/tag'
+require 'models/tagging'
+require 'models/comment'
+require 'models/sponsor'
+require 'models/member'
+require 'models/essay'
+require 'models/toy'
+require 'models/invoice'
+require 'models/line_item'
+require 'models/column'
+require 'models/record'
+
+class BelongsToAssociationsTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :developers, :projects, :topics,
+           :developers_projects, :computers, :authors, :author_addresses,
+           :posts, :tags, :taggings, :comments, :sponsors, :members
+
+  def test_belongs_to
+    firm = Client.find(3).firm
+    assert_not_nil firm
+    assert_equal companies(:first_firm).name, firm.name
+  end
+
+  def test_belongs_to_does_not_use_order_by
+    ActiveRecord::SQLCounter.clear_log
+    Client.find(3).firm
+  ensure
+    assert ActiveRecord::SQLCounter.log_all.all? { |sql| /order by/i !~ sql }, 'ORDER BY was used in the query'
+  end
+
+  def test_belongs_to_with_primary_key
+    client = Client.create(:name => "Primary key client", :firm_name => companies(:first_firm).name)
+    assert_equal companies(:first_firm).name, client.firm_with_primary_key.name
+  end
+
+  def test_belongs_to_with_primary_key_joins_on_correct_column
+    sql = Client.joins(:firm_with_primary_key).to_sql
+    if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+      assert_no_match(/`firm_with_primary_keys_companies`\.`id`/, sql)
+      assert_match(/`firm_with_primary_keys_companies`\.`name`/, sql)
+    elsif current_adapter?(:OracleAdapter)
+      # on Oracle aliases are truncated to 30 characters and are quoted in uppercase
+      assert_no_match(/"firm_with_primary_keys_compani"\."id"/i, sql)
+      assert_match(/"firm_with_primary_keys_compani"\."name"/i, sql)
+    else
+      assert_no_match(/"firm_with_primary_keys_companies"\."id"/, sql)
+      assert_match(/"firm_with_primary_keys_companies"\."name"/, sql)
+    end
+  end
+
+  def test_proxy_assignment
+    account = Account.find(1)
+    assert_nothing_raised { account.firm = account.firm }
+  end
+
+  def test_type_mismatch
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { Account.find(1).firm = 1 }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { Account.find(1).firm = Project.find(1) }
+  end
+
+  def test_natural_assignment
+    apple = Firm.create("name" => "Apple")
+    citibank = Account.create("credit_limit" => 10)
+    citibank.firm = apple
+    assert_equal apple.id, citibank.firm_id
+  end
+
+  def test_id_assignment
+    apple = Firm.create("name" => "Apple")
+    citibank = Account.create("credit_limit" => 10)
+    citibank.firm_id = apple
+    assert_nil citibank.firm_id
+  end
+
+  def test_natural_assignment_with_primary_key
+    apple = Firm.create("name" => "Apple")
+    citibank = Client.create("name" => "Primary key client")
+    citibank.firm_with_primary_key = apple
+    assert_equal apple.name, citibank.firm_name
+  end
+
+  def test_eager_loading_with_primary_key
+    Firm.create("name" => "Apple")
+    Client.create("name" => "Citibank", :firm_name => "Apple")
+    citibank_result = Client.all.merge!(:where => {:name => "Citibank"}, :includes => :firm_with_primary_key).first
+    assert citibank_result.association_cache.key?(:firm_with_primary_key)
+  end
+
+  def test_eager_loading_with_primary_key_as_symbol
+    Firm.create("name" => "Apple")
+    Client.create("name" => "Citibank", :firm_name => "Apple")
+    citibank_result = Client.all.merge!(:where => {:name => "Citibank"}, :includes => :firm_with_primary_key_symbols).first
+    assert citibank_result.association_cache.key?(:firm_with_primary_key_symbols)
+  end
+
+  def test_creating_the_belonging_object
+    citibank = Account.create("credit_limit" => 10)
+    apple    = citibank.create_firm("name" => "Apple")
+    assert_equal apple, citibank.firm
+    citibank.save
+    citibank.reload
+    assert_equal apple, citibank.firm
+  end
+
+  def test_creating_the_belonging_object_with_primary_key
+    client = Client.create(:name => "Primary key client")
+    apple  = client.create_firm_with_primary_key("name" => "Apple")
+    assert_equal apple, client.firm_with_primary_key
+    client.save
+    client.reload
+    assert_equal apple, client.firm_with_primary_key
+  end
+
+  def test_building_the_belonging_object
+    citibank = Account.create("credit_limit" => 10)
+    apple    = citibank.build_firm("name" => "Apple")
+    citibank.save
+    assert_equal apple.id, citibank.firm_id
+  end
+
+  def test_building_the_belonging_object_with_implicit_sti_base_class
+    account = Account.new
+    company = account.build_firm
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_belonging_object_with_explicit_sti_base_class
+    account = Account.new
+    company = account.build_firm(:type => "Company")
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_belonging_object_with_sti_subclass
+    account = Account.new
+    company = account.build_firm(:type => "Firm")
+    assert_kind_of Firm, company, "Expected #{company.class} to be a Firm"
+  end
+
+  def test_building_the_belonging_object_with_an_invalid_type
+    account = Account.new
+    assert_raise(ActiveRecord::SubclassNotFound) { account.build_firm(:type => "InvalidType") }
+  end
+
+  def test_building_the_belonging_object_with_an_unrelated_type
+    account = Account.new
+    assert_raise(ActiveRecord::SubclassNotFound) { account.build_firm(:type => "Account") }
+  end
+
+  def test_building_the_belonging_object_with_primary_key
+    client = Client.create(:name => "Primary key client")
+    apple  = client.build_firm_with_primary_key("name" => "Apple")
+    client.save
+    assert_equal apple.name, client.firm_name
+  end
+
+  def test_create!
+    client  = Client.create!(:name => "Jimmy")
+    account = client.create_account!(:credit_limit => 10)
+    assert_equal account, client.account
+    assert account.persisted?
+    client.save
+    client.reload
+    assert_equal account, client.account
+  end
+
+  def test_failing_create!
+    client  = Client.create!(:name => "Jimmy")
+    assert_raise(ActiveRecord::RecordInvalid) { client.create_account! }
+    assert_not_nil client.account
+    assert client.account.new_record?
+  end
+
+  def test_natural_assignment_to_nil
+    client = Client.find(3)
+    client.firm = nil
+    client.save
+    assert_nil client.firm(true)
+    assert_nil client.client_of
+  end
+
+  def test_natural_assignment_to_nil_with_primary_key
+    client = Client.create(:name => "Primary key client", :firm_name => companies(:first_firm).name)
+    client.firm_with_primary_key = nil
+    client.save
+    assert_nil client.firm_with_primary_key(true)
+    assert_nil client.client_of
+  end
+
+  def test_with_different_class_name
+    assert_equal Company.find(1).name, Company.find(3).firm_with_other_name.name
+    assert_not_nil Company.find(3).firm_with_other_name, "Microsoft should have a firm"
+  end
+
+  def test_with_condition
+    assert_equal Company.find(1).name, Company.find(3).firm_with_condition.name
+    assert_not_nil Company.find(3).firm_with_condition, "Microsoft should have a firm"
+  end
+
+  def test_polymorphic_association_class
+    sponsor = Sponsor.new
+    assert_nil sponsor.association(:sponsorable).send(:klass)
+
+    sponsor.sponsorable_type = '' # the column doesn't have to be declared NOT NULL
+    assert_nil sponsor.association(:sponsorable).send(:klass)
+
+    sponsor.sponsorable = Member.new :name => "Bert"
+    assert_equal Member, sponsor.association(:sponsorable).send(:klass)
+    assert_equal "members", sponsor.association(:sponsorable).aliased_table_name
+  end
+
+  def test_with_polymorphic_and_condition
+    sponsor = Sponsor.create
+    member = Member.create :name => "Bert"
+    sponsor.sponsorable = member
+
+    assert_equal member, sponsor.sponsorable
+    assert_nil sponsor.sponsorable_with_conditions
+  end
+
+  def test_with_select
+    assert_equal 1, Company.find(2).firm_with_select.attributes.size
+    assert_equal 1, Company.all.merge!(:includes => :firm_with_select ).find(2).firm_with_select.attributes.size
+  end
+
+  def test_belongs_to_counter
+    debate = Topic.create("title" => "debate")
+    assert_equal 0, debate.read_attribute("replies_count"), "No replies yet"
+
+    trash = debate.replies.create("title" => "blah!", "content" => "world around!")
+    assert_equal 1, Topic.find(debate.id).read_attribute("replies_count"), "First reply created"
+
+    trash.destroy
+    assert_equal 0, Topic.find(debate.id).read_attribute("replies_count"), "First reply deleted"
+  end
+
+  def test_belongs_to_counter_with_assigning_nil
+    post = Post.find(1)
+    comment = Comment.find(1)
+
+    assert_equal post.id, comment.post_id
+    assert_equal 2, Post.find(post.id).comments.size
+
+    comment.post = nil
+
+    assert_equal 1, Post.find(post.id).comments.size
+  end
+
+  def test_belongs_to_with_primary_key_counter
+    debate  = Topic.create("title" => "debate")
+    debate2 = Topic.create("title" => "debate2")
+    reply   = Reply.create("title" => "blah!", "content" => "world around!", "parent_title" => "debate")
+
+    assert_equal 1, debate.reload.replies_count
+    assert_equal 0, debate2.reload.replies_count
+
+    reply.topic_with_primary_key = debate2
+
+    assert_equal 0, debate.reload.replies_count
+    assert_equal 1, debate2.reload.replies_count
+
+    reply.topic_with_primary_key = nil
+
+    assert_equal 0, debate.reload.replies_count
+    assert_equal 0, debate2.reload.replies_count
+  end
+
+  def test_belongs_to_counter_with_reassigning
+    topic1 = Topic.create("title" => "t1")
+    topic2 = Topic.create("title" => "t2")
+    reply1 = Reply.new("title" => "r1", "content" => "r1")
+    reply1.topic = topic1
+
+    assert reply1.save
+    assert_equal 1, Topic.find(topic1.id).replies.size
+    assert_equal 0, Topic.find(topic2.id).replies.size
+
+    reply1.topic = Topic.find(topic2.id)
+
+    assert_no_queries do
+      reply1.topic = topic2
+    end
+
+    assert reply1.save
+    assert_equal 0, Topic.find(topic1.id).replies.size
+    assert_equal 1, Topic.find(topic2.id).replies.size
+
+    reply1.topic = nil
+
+    assert_equal 0, Topic.find(topic1.id).replies.size
+    assert_equal 0, Topic.find(topic2.id).replies.size
+
+    reply1.topic = topic1
+
+    assert_equal 1, Topic.find(topic1.id).replies.size
+    assert_equal 0, Topic.find(topic2.id).replies.size
+
+    reply1.destroy
+
+    assert_equal 0, Topic.find(topic1.id).replies.size
+    assert_equal 0, Topic.find(topic2.id).replies.size
+  end
+
+  def test_belongs_to_reassign_with_namespaced_models_and_counters
+    topic1 = Web::Topic.create("title" => "t1")
+    topic2 = Web::Topic.create("title" => "t2")
+    reply1 = Web::Reply.new("title" => "r1", "content" => "r1")
+    reply1.topic = topic1
+
+    assert reply1.save
+    assert_equal 1, Web::Topic.find(topic1.id).replies.size
+    assert_equal 0, Web::Topic.find(topic2.id).replies.size
+
+    reply1.topic = Web::Topic.find(topic2.id)
+
+    assert reply1.save
+    assert_equal 0, Web::Topic.find(topic1.id).replies.size
+    assert_equal 1, Web::Topic.find(topic2.id).replies.size
+  end
+
+  def test_belongs_to_counter_after_save
+    topic = Topic.create!(:title => "monday night")
+    topic.replies.create!(:title => "re: monday night", :content => "football")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+
+    topic.save!
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+  end
+
+  def test_belongs_to_with_touch_option_on_touch
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    assert_queries(1) { line_item.touch }
+  end
+
+  def test_belongs_to_with_touch_option_on_touch_without_updated_at_attributes
+    assert_not LineItem.column_names.include?("updated_at")
+
+    line_item = LineItem.create!
+    invoice = Invoice.create!(line_items: [line_item])
+    initial = invoice.updated_at
+    line_item.touch
+
+    assert_not_equal initial, invoice.reload.updated_at
+  end
+
+  def test_belongs_to_with_touch_option_on_touch_and_removed_parent
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    line_item.invoice = nil
+
+    assert_queries(2) { line_item.touch }
+  end
+
+  def test_belongs_to_with_touch_option_on_update
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    assert_queries(2) { line_item.update amount: 10 }
+  end
+
+  def test_belongs_to_with_touch_option_on_empty_update
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    assert_queries(0) { line_item.save }
+  end
+
+  def test_belongs_to_with_touch_option_on_destroy
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    assert_queries(2) { line_item.destroy }
+  end
+
+  def test_belongs_to_with_touch_option_on_destroy_with_destroyed_parent
+    line_item = LineItem.create!
+    invoice   = Invoice.create!(line_items: [line_item])
+    invoice.destroy
+
+    assert_queries(1) { line_item.destroy }
+  end
+
+  def test_belongs_to_with_touch_option_on_touch_and_reassigned_parent
+    line_item = LineItem.create!
+    Invoice.create!(line_items: [line_item])
+
+    line_item.invoice = Invoice.create!
+
+    assert_queries(3) { line_item.touch }
+  end
+
+  def test_belongs_to_counter_after_update
+    topic = Topic.create!(title: "37s")
+    topic.replies.create!(title: "re: 37s", content: "rails")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+
+    topic.update(title: "37signals")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+  end
+
+  def test_belongs_to_counter_when_update_columns
+    topic = Topic.create!(:title => "37s")
+    topic.replies.create!(:title => "re: 37s", :content => "rails")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+
+    topic.update_columns(content: "rails is wonderful")
+    assert_equal 1, Topic.find(topic.id)[:replies_count]
+  end
+
+  def test_assignment_before_child_saved
+    final_cut = Client.new("name" => "Final Cut")
+    firm = Firm.find(1)
+    final_cut.firm = firm
+    assert !final_cut.persisted?
+    assert final_cut.save
+    assert final_cut.persisted?
+    assert firm.persisted?
+    assert_equal firm, final_cut.firm
+    assert_equal firm, final_cut.firm(true)
+  end
+
+  def test_assignment_before_child_saved_with_primary_key
+    final_cut = Client.new("name" => "Final Cut")
+    firm = Firm.find(1)
+    final_cut.firm_with_primary_key = firm
+    assert !final_cut.persisted?
+    assert final_cut.save
+    assert final_cut.persisted?
+    assert firm.persisted?
+    assert_equal firm, final_cut.firm_with_primary_key
+    assert_equal firm, final_cut.firm_with_primary_key(true)
+  end
+
+  def test_new_record_with_foreign_key_but_no_object
+    client = Client.new("firm_id" => 1)
+    # sometimes tests on Oracle fail if ORDER BY is not provided therefore add always :order with :first
+    assert_equal Firm.all.merge!(:order => "id").first, client.firm_with_basic_id
+  end
+
+  def test_setting_foreign_key_after_nil_target_loaded
+    client = Client.new
+    client.firm_with_basic_id
+    client.firm_id = 1
+
+    assert_equal companies(:first_firm), client.firm_with_basic_id
+  end
+
+  def test_polymorphic_setting_foreign_key_after_nil_target_loaded
+    sponsor = Sponsor.new
+    sponsor.sponsorable
+    sponsor.sponsorable_id = 1
+    sponsor.sponsorable_type = "Member"
+
+    assert_equal members(:groucho), sponsor.sponsorable
+  end
+
+  def test_dont_find_target_when_foreign_key_is_null
+    tagging = taggings(:thinking_general)
+    assert_queries(0) { tagging.super_tag }
+  end
+
+  def test_field_name_same_as_foreign_key
+    computer = Computer.find(1)
+    assert_not_nil computer.developer, ":foreign key == attribute didn't lock up" # '
+  end
+
+  def test_counter_cache
+    topic = Topic.create :title => "Zoom-zoom-zoom"
+    assert_equal 0, topic[:replies_count]
+
+    reply = Reply.create(:title => "re: zoom", :content => "speedy quick!")
+    reply.topic = topic
+
+    assert_equal 1, topic.reload[:replies_count]
+    assert_equal 1, topic.replies.size
+
+    topic[:replies_count] = 15
+    assert_equal 15, topic.replies.size
+  end
+
+  def test_counter_cache_double_destroy
+    topic = Topic.create :title => "Zoom-zoom-zoom"
+
+    5.times do
+      topic.replies.create(:title => "re: zoom", :content => "speedy quick!")
+    end
+
+    assert_equal 5, topic.reload[:replies_count]
+    assert_equal 5, topic.replies.size
+
+    reply = topic.replies.first
+
+    reply.destroy
+    assert_equal 4, topic.reload[:replies_count]
+
+    reply.destroy
+    assert_equal 4, topic.reload[:replies_count]
+    assert_equal 4, topic.replies.size
+  end
+
+  def test_concurrent_counter_cache_double_destroy
+    topic = Topic.create :title => "Zoom-zoom-zoom"
+
+    5.times do
+      topic.replies.create(:title => "re: zoom", :content => "speedy quick!")
+    end
+
+    assert_equal 5, topic.reload[:replies_count]
+    assert_equal 5, topic.replies.size
+
+    reply = topic.replies.first
+    reply_clone = Reply.find(reply.id)
+
+    reply.destroy
+    assert_equal 4, topic.reload[:replies_count]
+
+    reply_clone.destroy
+    assert_equal 4, topic.reload[:replies_count]
+    assert_equal 4, topic.replies.size
+  end
+
+  def test_custom_counter_cache
+    reply = Reply.create(:title => "re: zoom", :content => "speedy quick!")
+    assert_equal 0, reply[:replies_count]
+
+    silly = SillyReply.create(:title => "gaga", :content => "boo-boo")
+    silly.reply = reply
+
+    assert_equal 1, reply.reload[:replies_count]
+    assert_equal 1, reply.replies.size
+
+    reply[:replies_count] = 17
+    assert_equal 17, reply.replies.size
+  end
+
+  def test_association_assignment_sticks
+    post = Post.first
+
+    author1, author2 = Author.all.merge!(:limit => 2).to_a
+    assert_not_nil author1
+    assert_not_nil author2
+
+    # make sure the association is loaded
+    post.author
+
+    # set the association by id, directly
+    post.author_id = author2.id
+
+    # save and reload
+    post.save!
+    post.reload
+
+    # the author id of the post should be the id we set
+    assert_equal post.author_id, author2.id
+  end
+
+  def test_cant_save_readonly_association
+    assert_raise(ActiveRecord::ReadOnlyRecord) { companies(:first_client).readonly_firm.save! }
+    assert companies(:first_client).readonly_firm.readonly?
+  end
+
+  def test_test_polymorphic_assignment_foreign_key_type_string
+    comment = Comment.first
+    comment.author   = Author.first
+    comment.resource = Member.first
+    comment.save
+
+    assert_equal Comment.all.to_a,
+      Comment.includes(:author).to_a
+
+    assert_equal Comment.all.to_a,
+      Comment.includes(:resource).to_a
+  end
+
+  def test_polymorphic_assignment_foreign_type_field_updating
+    # should update when assigning a saved record
+    sponsor = Sponsor.new
+    member = Member.create
+    sponsor.sponsorable = member
+    assert_equal "Member", sponsor.sponsorable_type
+
+    # should update when assigning a new record
+    sponsor = Sponsor.new
+    member = Member.new
+    sponsor.sponsorable = member
+    assert_equal "Member", sponsor.sponsorable_type
+  end
+
+  def test_polymorphic_assignment_with_primary_key_foreign_type_field_updating
+    # should update when assigning a saved record
+    essay = Essay.new
+    writer = Author.create(:name => "David")
+    essay.writer = writer
+    assert_equal "Author", essay.writer_type
+
+    # should update when assigning a new record
+    essay = Essay.new
+    writer = Author.new
+    essay.writer = writer
+    assert_equal "Author", essay.writer_type
+  end
+
+  def test_polymorphic_assignment_updates_foreign_id_field_for_new_and_saved_records
+    sponsor = Sponsor.new
+    saved_member = Member.create
+    new_member = Member.new
+
+    sponsor.sponsorable = saved_member
+    assert_equal saved_member.id, sponsor.sponsorable_id
+
+    sponsor.sponsorable = new_member
+    assert_nil sponsor.sponsorable_id
+  end
+
+  def test_assignment_updates_foreign_id_field_for_new_and_saved_records
+    client = Client.new
+    saved_firm = Firm.create :name => "Saved"
+    new_firm = Firm.new
+
+    client.firm = saved_firm
+    assert_equal saved_firm.id, client.client_of
+
+    client.firm = new_firm
+    assert_nil client.client_of
+  end
+
+  def test_polymorphic_assignment_with_primary_key_updates_foreign_id_field_for_new_and_saved_records
+    essay = Essay.new
+    saved_writer = Author.create(:name => "David")
+    new_writer = Author.new
+
+    essay.writer = saved_writer
+    assert_equal saved_writer.name, essay.writer_id
+
+    essay.writer = new_writer
+    assert_nil essay.writer_id
+  end
+
+  def test_polymorphic_assignment_with_nil
+    essay = Essay.new
+    assert_nil essay.writer_id
+    assert_nil essay.writer_type
+
+    essay.writer_id = 1
+    essay.writer_type = 'Author'
+
+    essay.writer = nil
+    assert_nil essay.writer_id
+    assert_nil essay.writer_type
+  end
+
+  def test_belongs_to_proxy_should_not_respond_to_private_methods
+    assert_raise(NoMethodError) { companies(:first_firm).private_method }
+    assert_raise(NoMethodError) { companies(:second_client).firm.private_method }
+  end
+
+  def test_belongs_to_proxy_should_respond_to_private_methods_via_send
+    companies(:first_firm).send(:private_method)
+    companies(:second_client).firm.send(:private_method)
+  end
+
+  def test_save_of_record_with_loaded_belongs_to
+    @account = companies(:first_firm).account
+
+    assert_nothing_raised do
+      Account.find(@account.id).save!
+      Account.all.merge!(:includes => :firm).find(@account.id).save!
+    end
+
+    @account.firm.delete
+
+    assert_nothing_raised do
+      Account.find(@account.id).save!
+      Account.all.merge!(:includes => :firm).find(@account.id).save!
+    end
+  end
+
+  def test_dependent_delete_and_destroy_with_belongs_to
+    AuthorAddress.destroyed_author_address_ids.clear
+
+    author_address = author_addresses(:david_address)
+    author_address_extra = author_addresses(:david_address_extra)
+    assert_equal [], AuthorAddress.destroyed_author_address_ids
+
+    assert_difference "AuthorAddress.count", -2 do
+      authors(:david).destroy
+    end
+
+    assert_equal [], AuthorAddress.where(id: [author_address.id, author_address_extra.id])
+    assert_equal [author_address.id], AuthorAddress.destroyed_author_address_ids
+  end
+
+  def test_belongs_to_invalid_dependent_option_raises_exception
+    error = assert_raise ArgumentError do
+      Class.new(Author).belongs_to :special_author_address, :dependent => :nullify
+    end
+    assert_equal error.message, 'The :dependent option must be one of [:destroy, :delete], but is :nullify'
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_belongs_to_association_with_where_clause
+    new_firm = accounts(:signals37).build_firm(:name => 'Apple')
+    assert_equal new_firm.name, "Apple"
+  end
+
+  def test_attributes_are_set_without_error_when_initialized_from_belongs_to_association_with_array_in_where_clause
+    new_account = Account.where(:credit_limit => [ 50, 60 ]).new
+    assert_nil new_account.credit_limit
+  end
+
+  def test_reassigning_the_parent_id_updates_the_object
+    client = companies(:second_client)
+
+    client.firm
+    client.firm_with_condition
+    firm_proxy                = client.send(:association_instance_get, :firm)
+    firm_with_condition_proxy = client.send(:association_instance_get, :firm_with_condition)
+
+    assert !firm_proxy.stale_target?
+    assert !firm_with_condition_proxy.stale_target?
+    assert_equal companies(:first_firm), client.firm
+    assert_equal companies(:first_firm), client.firm_with_condition
+
+    client.client_of = companies(:another_firm).id
+
+    assert firm_proxy.stale_target?
+    assert firm_with_condition_proxy.stale_target?
+    assert_equal companies(:another_firm), client.firm
+    assert_equal companies(:another_firm), client.firm_with_condition
+  end
+
+  def test_polymorphic_reassignment_of_associated_id_updates_the_object
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+
+    sponsor.sponsorable
+    proxy = sponsor.send(:association_instance_get, :sponsorable)
+
+    assert !proxy.stale_target?
+    assert_equal members(:groucho), sponsor.sponsorable
+
+    sponsor.sponsorable_id = members(:some_other_guy).id
+
+    assert proxy.stale_target?
+    assert_equal members(:some_other_guy), sponsor.sponsorable
+  end
+
+  def test_polymorphic_reassignment_of_associated_type_updates_the_object
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+
+    sponsor.sponsorable
+    proxy = sponsor.send(:association_instance_get, :sponsorable)
+
+    assert !proxy.stale_target?
+    assert_equal members(:groucho), sponsor.sponsorable
+
+    sponsor.sponsorable_type = 'Firm'
+
+    assert proxy.stale_target?
+    assert_equal companies(:first_firm), sponsor.sponsorable
+  end
+
+  def test_reloading_association_with_key_change
+    client = companies(:second_client)
+    firm = client.association(:firm)
+
+    client.firm = companies(:another_firm)
+    firm.reload
+    assert_equal companies(:another_firm), firm.target
+
+    client.client_of = companies(:first_firm).id
+    firm.reload
+    assert_equal companies(:first_firm), firm.target
+  end
+
+  def test_polymorphic_counter_cache
+    tagging = taggings(:welcome_general)
+    post    = posts(:welcome)
+    comment = comments(:greetings)
+
+    assert_difference lambda { post.reload.tags_count }, -1 do
+      assert_difference 'comment.reload.tags_count', +1 do
+        tagging.taggable = comment
+      end
+    end
+  end
+
+  def test_polymorphic_with_custom_foreign_type
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    groucho = members(:groucho)
+    other   = members(:some_other_guy)
+
+    assert_equal groucho, sponsor.sponsorable
+    assert_equal groucho, sponsor.thing
+
+    sponsor.thing = other
+
+    assert_equal other, sponsor.sponsorable
+    assert_equal other, sponsor.thing
+
+    sponsor.sponsorable = groucho
+
+    assert_equal groucho, sponsor.sponsorable
+    assert_equal groucho, sponsor.thing
+  end
+
+  def test_build_with_conditions
+    client = companies(:second_client)
+    firm   = client.build_bob_firm
+
+    assert_equal "Bob", firm.name
+  end
+
+  def test_create_with_conditions
+    client = companies(:second_client)
+    firm   = client.create_bob_firm
+
+    assert_equal "Bob", firm.name
+  end
+
+  def test_create_bang_with_conditions
+    client = companies(:second_client)
+    firm   = client.create_bob_firm!
+
+    assert_equal "Bob", firm.name
+  end
+
+  def test_build_with_block
+    client = Client.create(:name => 'Client Company')
+
+    firm = client.build_firm{ |f| f.name = 'Agency Company' }
+    assert_equal 'Agency Company', firm.name
+  end
+
+  def test_create_with_block
+    client = Client.create(:name => 'Client Company')
+
+    firm = client.create_firm{ |f| f.name = 'Agency Company' }
+    assert_equal 'Agency Company', firm.name
+  end
+
+  def test_create_bang_with_block
+    client = Client.create(:name => 'Client Company')
+
+    firm = client.create_firm!{ |f| f.name = 'Agency Company' }
+    assert_equal 'Agency Company', firm.name
+  end
+
+  def test_should_set_foreign_key_on_create_association
+    client = Client.create! :name => "fuu"
+
+    firm = client.create_firm :name => "baa"
+    assert_equal firm.id, client.client_of
+  end
+
+  def test_should_set_foreign_key_on_create_association!
+    client = Client.create! :name => "fuu"
+
+    firm = client.create_firm! :name => "baa"
+    assert_equal firm.id, client.client_of
+  end
+
+  def test_self_referential_belongs_to_with_counter_cache_assigning_nil
+    comment = Comment.create! :post => posts(:thinking), :body => "fuu"
+    comment.parent = nil
+    comment.save!
+
+    assert_equal nil, comment.reload.parent
+    assert_equal 0, comments(:greetings).reload.children_count
+  end
+
+  def test_belongs_to_with_id_assigning
+    post = posts(:welcome)
+    comment = Comment.create! body: "foo", post: post
+    parent = comments(:greetings)
+    assert_equal 0, parent.reload.children_count
+    comment.parent_id = parent.id
+
+    comment.save!
+    assert_equal 1, parent.reload.children_count
+  end
+
+  def test_polymorphic_with_custom_primary_key
+    toy = Toy.create!
+    sponsor = Sponsor.create!(:sponsorable => toy)
+
+    assert_equal toy, sponsor.reload.sponsorable
+  end
+
+  test "stale tracking doesn't care about the type" do
+    apple = Firm.create("name" => "Apple")
+    citibank = Account.create("credit_limit" => 10)
+
+    citibank.firm_id = apple.id
+    citibank.firm # load it
+
+    citibank.firm_id = apple.id.to_s
+
+    assert !citibank.association(:firm).stale_target?
+  end
+
+  def test_reflect_the_most_recent_change
+    author1, author2 = Author.limit(2)
+    post = Post.new(:title => "foo", :body=> "bar")
+
+    post.author    = author1
+    post.author_id = author2.id
+
+    assert post.save
+    assert_equal post.author_id, author2.id
+  end
+
+  test 'dangerous association name raises ArgumentError' do
+    [:errors, 'errors', :save, 'save'].each do |name|
+      assert_raises(ArgumentError, "Association #{name} should not be allowed") do
+        Class.new(ActiveRecord::Base) do
+          belongs_to name
+        end
+      end
+    end
+  end
+
+  test 'belongs_to works with model called Record' do
+    record = Record.create!
+    Column.create! record: record
+    assert_equal 1, Column.count
+  end
+end
+
+class BelongsToWithForeignKeyTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses
+
+  def test_destroy_linked_models
+    address = AuthorAddress.create!
+    author = Author.create! name: "Author", author_address_id: address.id
+
+    author.destroy!
+  end
+end
diff --git a/activerecord/test/cases/associations/callbacks_test.rb b/activerecord/test/cases/associations/callbacks_test.rb
new file mode 100644
index 0000000000..5b7e462f64
--- /dev/null
+++ b/activerecord/test/cases/associations/callbacks_test.rb
@@ -0,0 +1,189 @@
+require "cases/helper"
+require 'models/post'
+require 'models/author'
+require 'models/project'
+require 'models/developer'
+require 'models/company'
+
+class AssociationCallbacksTest < ActiveRecord::TestCase
+  fixtures :posts, :authors, :projects, :developers
+
+  def setup
+    @david = authors(:david)
+    @thinking = posts(:thinking)
+    @authorless = posts(:authorless)
+    assert @david.post_log.empty?
+  end
+
+  def test_adding_macro_callbacks
+    @david.posts_with_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "after_adding#{@thinking.id}"], @david.post_log
+    @david.posts_with_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "after_adding#{@thinking.id}", "before_adding#{@thinking.id}",
+                  "after_adding#{@thinking.id}"], @david.post_log
+  end
+
+  def test_adding_with_proc_callbacks
+    @david.posts_with_proc_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "after_adding#{@thinking.id}"], @david.post_log
+    @david.posts_with_proc_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "after_adding#{@thinking.id}", "before_adding#{@thinking.id}",
+                  "after_adding#{@thinking.id}"], @david.post_log
+  end
+
+  def test_removing_with_macro_callbacks
+    first_post, second_post = @david.posts_with_callbacks[0, 2]
+    @david.posts_with_callbacks.delete(first_post)
+    assert_equal ["before_removing#{first_post.id}", "after_removing#{first_post.id}"], @david.post_log
+    @david.posts_with_callbacks.delete(second_post)
+    assert_equal ["before_removing#{first_post.id}", "after_removing#{first_post.id}", "before_removing#{second_post.id}",
+                  "after_removing#{second_post.id}"], @david.post_log
+  end
+
+  def test_removing_with_proc_callbacks
+    first_post, second_post = @david.posts_with_callbacks[0, 2]
+    @david.posts_with_proc_callbacks.delete(first_post)
+    assert_equal ["before_removing#{first_post.id}", "after_removing#{first_post.id}"], @david.post_log
+    @david.posts_with_proc_callbacks.delete(second_post)
+    assert_equal ["before_removing#{first_post.id}", "after_removing#{first_post.id}", "before_removing#{second_post.id}",
+                  "after_removing#{second_post.id}"], @david.post_log
+  end
+
+  def test_multiple_callbacks
+    @david.posts_with_multiple_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "before_adding_proc#{@thinking.id}", "after_adding#{@thinking.id}",
+                  "after_adding_proc#{@thinking.id}"], @david.post_log
+    @david.posts_with_multiple_callbacks << @thinking
+    assert_equal ["before_adding#{@thinking.id}", "before_adding_proc#{@thinking.id}", "after_adding#{@thinking.id}",
+                  "after_adding_proc#{@thinking.id}", "before_adding#{@thinking.id}", "before_adding_proc#{@thinking.id}",
+                  "after_adding#{@thinking.id}", "after_adding_proc#{@thinking.id}"], @david.post_log
+  end
+
+  def test_has_many_callbacks_with_create
+    morten = Author.create :name => "Morten"
+    post = morten.posts_with_proc_callbacks.create! :title => "Hello", :body => "How are you doing?"
+    assert_equal ["before_adding<new>", "after_adding#{post.id}"], morten.post_log
+  end
+
+  def test_has_many_callbacks_with_create!
+    morten = Author.create! :name => "Morten"
+    post = morten.posts_with_proc_callbacks.create :title => "Hello", :body => "How are you doing?"
+    assert_equal ["before_adding<new>", "after_adding#{post.id}"], morten.post_log
+  end
+
+  def test_has_many_callbacks_for_save_on_parent
+    jack = Author.new :name => "Jack"
+    jack.posts_with_callbacks.build :title => "Call me back!", :body => "Before you wake up and after you sleep"
+
+    callback_log = ["before_adding<new>", "after_adding#{jack.posts_with_callbacks.first.id}"]
+    assert_equal callback_log, jack.post_log
+    assert jack.save
+    assert_equal 1, jack.posts_with_callbacks.count
+    assert_equal callback_log, jack.post_log
+  end
+
+  def test_has_many_callbacks_for_destroy_on_parent
+    firm = Firm.create! :name => "Firm"
+    client = firm.clients.create! :name => "Client"
+    firm.destroy
+
+    assert_equal ["before_remove#{client.id}", "after_remove#{client.id}"], firm.log
+  end
+
+  def test_has_and_belongs_to_many_add_callback
+    david = developers(:david)
+    ar = projects(:active_record)
+    assert ar.developers_log.empty?
+    ar.developers_with_callbacks << david
+    assert_equal ["before_adding#{david.id}", "after_adding#{david.id}"], ar.developers_log
+    ar.developers_with_callbacks << david
+    assert_equal ["before_adding#{david.id}", "after_adding#{david.id}", "before_adding#{david.id}",
+                  "after_adding#{david.id}"], ar.developers_log
+  end
+
+  def test_has_and_belongs_to_many_before_add_called_before_save
+    dev     = nil
+    new_dev = nil
+    klass = Class.new(Project) do
+      def self.name; Project.name; end
+      has_and_belongs_to_many :developers_with_callbacks,
+                                :class_name => "Developer",
+                                :before_add => lambda { |o,r|
+        dev     = r
+        new_dev = r.new_record?
+      }
+    end
+    rec = klass.create!
+    alice = Developer.new(:name => 'alice')
+    rec.developers_with_callbacks << alice
+    assert_equal alice, dev
+    assert_not_nil new_dev
+    assert new_dev, "record should not have been saved"
+    assert_not alice.new_record?
+  end
+
+  def test_has_and_belongs_to_many_after_add_called_after_save
+    ar = projects(:active_record)
+    assert ar.developers_log.empty?
+    alice = Developer.new(:name => 'alice')
+    ar.developers_with_callbacks << alice
+    assert_equal"after_adding#{alice.id}", ar.developers_log.last
+
+    bob = ar.developers_with_callbacks.create(:name => 'bob')
+    assert_equal "after_adding#{bob.id}", ar.developers_log.last
+
+    ar.developers_with_callbacks.build(:name => 'charlie')
+    assert_equal "after_adding<new>", ar.developers_log.last
+  end
+
+
+  def test_has_and_belongs_to_many_remove_callback
+    david = developers(:david)
+    jamis = developers(:jamis)
+    activerecord = projects(:active_record)
+    assert activerecord.developers_log.empty?
+    activerecord.developers_with_callbacks.delete(david)
+    assert_equal ["before_removing#{david.id}", "after_removing#{david.id}"], activerecord.developers_log
+
+    activerecord.developers_with_callbacks.delete(jamis)
+    assert_equal ["before_removing#{david.id}", "after_removing#{david.id}", "before_removing#{jamis.id}",
+                  "after_removing#{jamis.id}"], activerecord.developers_log
+  end
+
+  def test_has_and_belongs_to_many_does_not_fire_callbacks_on_clear
+    activerecord = projects(:active_record)
+    assert activerecord.developers_log.empty?
+    if activerecord.developers_with_callbacks.size == 0
+      activerecord.developers << developers(:david)
+      activerecord.developers << developers(:jamis)
+      activerecord.reload
+      assert activerecord.developers_with_callbacks.size == 2
+    end
+    activerecord.developers_with_callbacks.flat_map {|d| ["before_removing#{d.id}","after_removing#{d.id}"]}.sort
+    assert activerecord.developers_with_callbacks.clear
+    assert_predicate activerecord.developers_log, :empty?
+  end
+
+  def test_has_many_and_belongs_to_many_callbacks_for_save_on_parent
+    project = Project.new :name => "Callbacks"
+    project.developers_with_callbacks.build :name => "Jack", :salary => 95000
+
+    callback_log = ["before_adding<new>", "after_adding<new>"]
+    assert_equal callback_log, project.developers_log
+    assert project.save
+    assert_equal 1, project.developers_with_callbacks.size
+    assert_equal callback_log, project.developers_log
+  end
+
+  def test_dont_add_if_before_callback_raises_exception
+    assert !@david.unchangable_posts.include?(@authorless)
+    begin
+      @david.unchangable_posts << @authorless
+    rescue Exception
+    end
+    assert @david.post_log.empty?
+    assert !@david.unchangable_posts.include?(@authorless)
+    @david.reload
+    assert !@david.unchangable_posts.include?(@authorless)
+  end
+end
diff --git a/activerecord/test/cases/associations/cascaded_eager_loading_test.rb b/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
new file mode 100644
index 0000000000..51d8e0523e
--- /dev/null
+++ b/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
@@ -0,0 +1,188 @@
+require "cases/helper"
+require 'models/post'
+require 'models/comment'
+require 'models/author'
+require 'models/categorization'
+require 'models/category'
+require 'models/company'
+require 'models/topic'
+require 'models/reply'
+require 'models/person'
+require 'models/vertex'
+require 'models/edge'
+
+class CascadedEagerLoadingTest < ActiveRecord::TestCase
+  fixtures :authors, :mixins, :companies, :posts, :topics, :accounts, :comments,
+           :categorizations, :people, :categories, :edges, :vertices
+
+  def test_eager_association_loading_with_cascaded_two_levels
+    authors = Author.all.merge!(:includes=>{:posts=>:comments}, :order=>"authors.id").to_a
+    assert_equal 3, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 3, authors[1].posts.size
+    assert_equal 10, authors[0].posts.collect{|post| post.comments.size }.inject(0){|sum,i| sum+i}
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_and_one_level
+    authors = Author.all.merge!(:includes=>[{:posts=>:comments}, :categorizations], :order=>"authors.id").to_a
+    assert_equal 3, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 3, authors[1].posts.size
+    assert_equal 10, authors[0].posts.collect{|post| post.comments.size }.inject(0){|sum,i| sum+i}
+    assert_equal 1, authors[0].categorizations.size
+    assert_equal 2, authors[1].categorizations.size
+  end
+
+  def test_eager_association_loading_with_hmt_does_not_table_name_collide_when_joining_associations
+    assert_nothing_raised do
+      Author.joins(:posts).eager_load(:comments).where(:posts => {:tags_count => 1}).to_a
+    end
+    authors = Author.joins(:posts).eager_load(:comments).where(:posts => {:tags_count => 1}).to_a
+    assert_equal 1, assert_no_queries { authors.size }
+    assert_equal 10, assert_no_queries { authors[0].comments.size }
+  end
+
+  def test_eager_association_loading_grafts_stashed_associations_to_correct_parent
+    assert_nothing_raised do
+      Person.eager_load(:primary_contact => :primary_contact).where('primary_contacts_people_2.first_name = ?', 'Susan').order('people.id').to_a
+    end
+    assert_equal people(:michael), Person.eager_load(:primary_contact => :primary_contact).where('primary_contacts_people_2.first_name = ?', 'Susan').order('people.id').first
+  end
+
+  def test_cascaded_eager_association_loading_with_join_for_count
+    categories = Category.joins(:categorizations).includes([{:posts=>:comments}, :authors])
+
+    assert_equal 4, categories.count
+    assert_equal 4, categories.to_a.count
+    assert_equal 3, categories.distinct.count
+    assert_equal 3, categories.to_a.uniq.size # Must uniq since instantiating with inner joins will get dupes
+  end
+
+  def test_cascaded_eager_association_loading_with_duplicated_includes
+    categories = Category.includes(:categorizations).includes(:categorizations => :author).where("categorizations.id is not null").references(:categorizations)
+    assert_nothing_raised do
+      assert_equal 3, categories.count
+      assert_equal 3, categories.to_a.size
+    end
+  end
+
+  def test_cascaded_eager_association_loading_with_twice_includes_edge_cases
+    categories = Category.includes(:categorizations => :author).includes(:categorizations => :post).where("posts.id is not null").references(:posts)
+    assert_nothing_raised do
+      assert_equal 3, categories.count
+      assert_equal 3, categories.to_a.size
+    end
+  end
+
+  def test_eager_association_loading_with_join_for_count
+    authors = Author.joins(:special_posts).includes([:posts, :categorizations])
+
+    assert_nothing_raised { authors.count }
+    assert_queries(3) { authors.to_a }
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_with_two_has_many_associations
+    authors = Author.all.merge!(:includes=>{:posts=>[:comments, :categorizations]}, :order=>"authors.id").to_a
+    assert_equal 3, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 3, authors[1].posts.size
+    assert_equal 10, authors[0].posts.collect{|post| post.comments.size }.inject(0){|sum,i| sum+i}
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_and_self_table_reference
+    authors = Author.all.merge!(:includes=>{:posts=>[:comments, :author]}, :order=>"authors.id").to_a
+    assert_equal 3, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal authors(:david).name, authors[0].name
+    assert_equal [authors(:david).name], authors[0].posts.collect{|post| post.author.name}.uniq
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_with_condition
+    authors = Author.all.merge!(:includes=>{:posts=>:comments}, :where=>"authors.id=1", :order=>"authors.id").to_a
+    assert_equal 1, authors.size
+    assert_equal 5, authors[0].posts.size
+  end
+
+  def test_eager_association_loading_with_cascaded_three_levels_by_ping_pong
+    firms = Firm.all.merge!(:includes=>{:account=>{:firm=>:account}}, :order=>"companies.id").to_a
+    assert_equal 2, firms.size
+    assert_equal firms.first.account, firms.first.account.firm.account
+    assert_equal companies(:first_firm).account, assert_no_queries { firms.first.account.firm.account }
+    assert_equal companies(:first_firm).account.firm.account, assert_no_queries { firms.first.account.firm.account }
+  end
+
+  def test_eager_association_loading_with_has_many_sti
+    topics = Topic.all.merge!(:includes => :replies, :order => 'topics.id').to_a
+    first, second, = topics(:first).replies.size, topics(:second).replies.size
+    assert_no_queries do
+      assert_equal first, topics[0].replies.size
+      assert_equal second, topics[1].replies.size
+    end
+  end
+
+  def test_eager_association_loading_with_has_many_sti_and_subclasses
+    silly = SillyReply.new(:title => "gaga", :content => "boo-boo", :parent_id => 1)
+    silly.parent_id = 1
+    assert silly.save
+
+    topics = Topic.all.merge!(:includes => :replies, :order => ['topics.id', 'replies_topics.id']).to_a
+    assert_no_queries do
+      assert_equal 2, topics[0].replies.size
+      assert_equal 0, topics[1].replies.size
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_sti
+    replies = Reply.all.merge!(:includes => :topic, :order => 'topics.id').to_a
+    assert replies.include?(topics(:second))
+    assert !replies.include?(topics(:first))
+    assert_equal topics(:first), assert_no_queries { replies.first.topic }
+  end
+
+  def test_eager_association_loading_with_multiple_stis_and_order
+    author = Author.all.merge!(:includes => { :posts => [ :special_comments , :very_special_comment ] }, :order => ['authors.name', 'comments.body', 'very_special_comments_posts.body'], :where => 'posts.id = 4').first
+    assert_equal authors(:david), author
+    assert_no_queries do
+      author.posts.first.special_comments
+      author.posts.first.very_special_comment
+    end
+  end
+
+  def test_eager_association_loading_of_stis_with_multiple_references
+    authors = Author.all.merge!(:includes => { :posts => { :special_comments => { :post => [ :special_comments, :very_special_comment ] } } }, :order => 'comments.body, very_special_comments_posts.body', :where => 'posts.id = 4').to_a
+    assert_equal [authors(:david)], authors
+    assert_no_queries do
+      authors.first.posts.first.special_comments.first.post.special_comments
+      authors.first.posts.first.special_comments.first.post.very_special_comment
+    end
+  end
+
+  def test_eager_association_loading_where_first_level_returns_nil
+    authors = Author.all.merge!(:includes => {:post_about_thinking => :comments}, :order => 'authors.id DESC').to_a
+    assert_equal [authors(:bob), authors(:mary), authors(:david)], authors
+    assert_no_queries do
+      authors[2].post_about_thinking.comments.first
+    end
+  end
+
+  def test_eager_association_loading_with_recursive_cascading_four_levels_has_many_through
+    source = Vertex.all.merge!(:includes=>{:sinks=>{:sinks=>{:sinks=>:sinks}}}, :order => 'vertices.id').first
+    assert_equal vertices(:vertex_4), assert_no_queries { source.sinks.first.sinks.first.sinks.first }
+  end
+
+  def test_eager_association_loading_with_recursive_cascading_four_levels_has_and_belongs_to_many
+    sink = Vertex.all.merge!(:includes=>{:sources=>{:sources=>{:sources=>:sources}}}, :order => 'vertices.id DESC').first
+    assert_equal vertices(:vertex_1), assert_no_queries { sink.sources.first.sources.first.sources.first.sources.first }
+  end
+
+  def test_eager_association_loading_with_cascaded_interdependent_one_level_and_two_levels
+    authors_relation = Author.all.merge!(includes: [:comments, { posts: :categorizations }], order: "authors.id")
+    authors = authors_relation.to_a
+    assert_equal 3, authors.size
+    assert_equal 10, authors[0].comments.size
+    assert_equal 1, authors[1].comments.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 3, authors[1].posts.size
+    assert_equal 3, authors[0].posts.collect { |post| post.categorizations.size }.inject(0) { |sum, i| sum+i }
+  end
+end
diff --git a/activerecord/test/cases/associations/deprecated_counter_cache_on_has_many_through_test.rb b/activerecord/test/cases/associations/deprecated_counter_cache_on_has_many_through_test.rb
new file mode 100644
index 0000000000..48f7ddbe83
--- /dev/null
+++ b/activerecord/test/cases/associations/deprecated_counter_cache_on_has_many_through_test.rb
@@ -0,0 +1,26 @@
+require "cases/helper"
+
+class DeprecatedCounterCacheOnHasManyThroughTest < ActiveRecord::TestCase
+  class Post < ActiveRecord::Base
+    has_many :taggings, as: :taggable
+    has_many :tags, through: :taggings
+  end
+
+  class Tagging < ActiveRecord::Base
+    belongs_to :taggable, polymorphic: true
+    belongs_to :tag
+  end
+
+  class Tag < ActiveRecord::Base
+  end
+
+  test "counter caches are updated in the database if the belongs_to association doesn't specify a counter cache" do
+    post = Post.create!(title: 'Hello', body: 'World!')
+    assert_deprecated { post.tags << Tag.create!(name: 'whatever') }
+
+    assert_equal 1, post.tags.size
+    assert_equal 1, post.tags_count
+    assert_equal 1, post.reload.tags.size
+    assert_equal 1, post.reload.tags_count
+  end
+end
diff --git a/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
new file mode 100644
index 0000000000..75a6295350
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
@@ -0,0 +1,36 @@
+require 'cases/helper'
+require 'models/post'
+require 'models/tagging'
+
+module Namespaced
+  class Post < ActiveRecord::Base
+    self.table_name = 'posts'
+    has_one :tagging, :as => :taggable, :class_name => 'Tagging'
+  end
+end
+
+class EagerLoadIncludeFullStiClassNamesTest < ActiveRecord::TestCase
+
+  def setup
+    generate_test_objects
+  end
+
+  def generate_test_objects
+    post = Namespaced::Post.create( :title => 'Great stuff', :body => 'This is not', :author_id => 1 )
+    Tagging.create( :taggable => post )
+  end
+
+  def test_class_names
+    old = ActiveRecord::Base.store_full_sti_class
+
+    ActiveRecord::Base.store_full_sti_class = false
+    post = Namespaced::Post.includes(:tagging).find_by_title('Great stuff')
+    assert_nil post.tagging
+
+    ActiveRecord::Base.store_full_sti_class = true
+    post = Namespaced::Post.includes(:tagging).find_by_title('Great stuff')
+    assert_instance_of Tagging, post.tagging
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+end
diff --git a/activerecord/test/cases/associations/eager_load_nested_include_test.rb b/activerecord/test/cases/associations/eager_load_nested_include_test.rb
new file mode 100644
index 0000000000..0ff87d53ea
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_load_nested_include_test.rb
@@ -0,0 +1,128 @@
+require 'cases/helper'
+require 'models/post'
+require 'models/tag'
+require 'models/author'
+require 'models/comment'
+require 'models/category'
+require 'models/categorization'
+require 'models/tagging'
+
+module Remembered
+  extend ActiveSupport::Concern
+
+  included do
+    after_create :remember
+  protected
+    def remember; self.class.remembered << self; end
+  end
+
+  module ClassMethods
+    def remembered; @@remembered ||= []; end
+    def sample; @@remembered.sample; end
+  end
+end
+
+class ShapeExpression < ActiveRecord::Base
+  belongs_to :shape, :polymorphic => true
+  belongs_to :paint, :polymorphic => true
+end
+
+class Circle < ActiveRecord::Base
+  has_many :shape_expressions, :as => :shape
+  include Remembered
+end
+class Square < ActiveRecord::Base
+  has_many :shape_expressions, :as => :shape
+  include Remembered
+end
+class Triangle < ActiveRecord::Base
+  has_many :shape_expressions, :as => :shape
+  include Remembered
+end
+class PaintColor  < ActiveRecord::Base
+  has_many   :shape_expressions, :as => :paint
+  belongs_to :non_poly, :foreign_key => "non_poly_one_id", :class_name => "NonPolyOne"
+  include Remembered
+end
+class PaintTexture < ActiveRecord::Base
+  has_many   :shape_expressions, :as => :paint
+  belongs_to :non_poly, :foreign_key => "non_poly_two_id", :class_name => "NonPolyTwo"
+  include Remembered
+end
+class NonPolyOne < ActiveRecord::Base
+  has_many :paint_colors
+  include Remembered
+end
+class NonPolyTwo < ActiveRecord::Base
+  has_many :paint_textures
+  include Remembered
+end
+
+
+
+class EagerLoadPolyAssocsTest < ActiveRecord::TestCase
+  NUM_SIMPLE_OBJS = 50
+  NUM_SHAPE_EXPRESSIONS = 100
+
+  def setup
+    generate_test_object_graphs
+  end
+
+  teardown do
+    [Circle, Square, Triangle, PaintColor, PaintTexture,
+     ShapeExpression, NonPolyOne, NonPolyTwo].each do |c|
+      c.delete_all
+    end
+  end
+
+  def generate_test_object_graphs
+    1.upto(NUM_SIMPLE_OBJS) do
+      [Circle, Square, Triangle, NonPolyOne, NonPolyTwo].map(&:create!)
+    end
+    1.upto(NUM_SIMPLE_OBJS) do
+      PaintColor.create!(:non_poly_one_id => NonPolyOne.sample.id)
+      PaintTexture.create!(:non_poly_two_id => NonPolyTwo.sample.id)
+    end
+    1.upto(NUM_SHAPE_EXPRESSIONS) do
+      shape_type = [Circle, Square, Triangle].sample
+      paint_type = [PaintColor, PaintTexture].sample
+      ShapeExpression.create!(:shape_type => shape_type.to_s, :shape_id => shape_type.sample.id,
+                              :paint_type => paint_type.to_s, :paint_id => paint_type.sample.id)
+    end
+  end
+
+  def test_include_query
+    res = ShapeExpression.all.merge!(:includes => [ :shape, { :paint => :non_poly } ]).to_a
+    assert_equal NUM_SHAPE_EXPRESSIONS, res.size
+    assert_queries(0) do
+      res.each do |se|
+        assert_not_nil se.paint.non_poly, "this is the association that was loading incorrectly before the change"
+        assert_not_nil se.shape, "just making sure other associations still work"
+      end
+    end
+  end
+end
+
+class EagerLoadNestedIncludeWithMissingDataTest < ActiveRecord::TestCase
+  def setup
+    @davey_mcdave = Author.create(:name => 'Davey McDave')
+    @first_post = @davey_mcdave.posts.create(:title => 'Davey Speaks', :body => 'Expressive wordage')
+    @first_comment = @first_post.comments.create(:body => 'Inflamatory doublespeak')
+    @first_categorization = @davey_mcdave.categorizations.create(:category => Category.first, :post => @first_post)
+  end
+
+  teardown do
+    @davey_mcdave.destroy
+    @first_post.destroy
+    @first_comment.destroy
+    @first_categorization.destroy
+  end
+
+  def test_missing_data_in_a_nested_include_should_not_cause_errors_when_constructing_objects
+    assert_nothing_raised do
+      # @davey_mcdave doesn't have any author_favorites
+      includes = {:posts => :comments, :categorizations => :category, :author_favorites => :favorite_author }
+      Author.all.merge!(:includes => includes, :where => {:authors => {:name => @davey_mcdave.name}}, :order => 'categories.name').to_a
+    end
+  end
+end
diff --git a/activerecord/test/cases/associations/eager_singularization_test.rb b/activerecord/test/cases/associations/eager_singularization_test.rb
new file mode 100644
index 0000000000..a61a070331
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_singularization_test.rb
@@ -0,0 +1,148 @@
+require "cases/helper"
+
+
+if ActiveRecord::Base.connection.supports_migrations?
+class EagerSingularizationTest < ActiveRecord::TestCase
+  class Virus < ActiveRecord::Base
+    belongs_to :octopus
+  end
+
+  class Octopus < ActiveRecord::Base
+    has_one :virus
+  end
+
+  class Pass < ActiveRecord::Base
+    belongs_to :bus
+  end
+
+  class Bus < ActiveRecord::Base
+    has_many :passes
+  end
+
+  class Mess < ActiveRecord::Base
+    has_and_belongs_to_many :crises
+  end
+
+  class Crisis < ActiveRecord::Base
+    has_and_belongs_to_many :messes
+    has_many :analyses, :dependent => :destroy
+    has_many :successes, :through => :analyses
+    has_many :dresses, :dependent => :destroy
+    has_many :compresses, :through => :dresses
+  end
+
+  class Analysis < ActiveRecord::Base
+    belongs_to :crisis
+    belongs_to :success
+  end
+
+  class Success < ActiveRecord::Base
+    has_many :analyses, :dependent => :destroy
+    has_many :crises, :through => :analyses
+  end
+
+  class Dress < ActiveRecord::Base
+    belongs_to :crisis
+    has_many :compresses
+  end
+
+  class Compress < ActiveRecord::Base
+    belongs_to :dress
+  end
+
+  def setup
+    connection.create_table :viri do |t|
+      t.column :octopus_id, :integer
+      t.column :species, :string
+    end
+    connection.create_table :octopi do |t|
+      t.column :species, :string
+    end
+    connection.create_table :passes do |t|
+      t.column :bus_id, :integer
+      t.column :rides, :integer
+    end
+    connection.create_table :buses do |t|
+      t.column :name, :string
+    end
+    connection.create_table :crises_messes, :id => false do |t|
+      t.column :crisis_id, :integer
+      t.column :mess_id, :integer
+    end
+    connection.create_table :messes do |t|
+      t.column :name, :string
+    end
+    connection.create_table :crises do |t|
+      t.column :name, :string
+    end
+    connection.create_table :successes do |t|
+      t.column :name, :string
+    end
+    connection.create_table :analyses do |t|
+      t.column :crisis_id, :integer
+      t.column :success_id, :integer
+    end
+    connection.create_table :dresses do |t|
+      t.column :crisis_id, :integer
+    end
+    connection.create_table :compresses do |t|
+      t.column :dress_id, :integer
+    end
+  end
+
+  teardown do
+    connection.drop_table :viri
+    connection.drop_table :octopi
+    connection.drop_table :passes
+    connection.drop_table :buses
+    connection.drop_table :crises_messes
+    connection.drop_table :messes
+    connection.drop_table :crises
+    connection.drop_table :successes
+    connection.drop_table :analyses
+    connection.drop_table :dresses
+    connection.drop_table :compresses
+  end
+
+  def connection
+    ActiveRecord::Base.connection
+  end
+
+  def test_eager_no_extra_singularization_belongs_to
+    assert_nothing_raised do
+      Virus.all.merge!(:includes => :octopus).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_one
+    assert_nothing_raised do
+      Octopus.all.merge!(:includes => :virus).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_many
+    assert_nothing_raised do
+      Bus.all.merge!(:includes => :passes).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_and_belongs_to_many
+    assert_nothing_raised do
+      Crisis.all.merge!(:includes => :messes).to_a
+      Mess.all.merge!(:includes => :crises).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_many_through_belongs_to
+    assert_nothing_raised do
+      Crisis.all.merge!(:includes => :successes).to_a
+    end
+  end
+
+  def test_eager_no_extra_singularization_has_many_through_has_many
+    assert_nothing_raised do
+      Crisis.all.merge!(:includes => :compresses).to_a
+    end
+  end
+end
+end
diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
new file mode 100644
index 0000000000..21912fdf0f
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -0,0 +1,1293 @@
+require "cases/helper"
+require 'models/post'
+require 'models/tagging'
+require 'models/tag'
+require 'models/comment'
+require 'models/author'
+require 'models/essay'
+require 'models/category'
+require 'models/company'
+require 'models/person'
+require 'models/reader'
+require 'models/owner'
+require 'models/pet'
+require 'models/reference'
+require 'models/job'
+require 'models/subscriber'
+require 'models/subscription'
+require 'models/book'
+require 'models/developer'
+require 'models/project'
+require 'models/member'
+require 'models/membership'
+require 'models/club'
+require 'models/categorization'
+require 'models/sponsor'
+
+class EagerAssociationTest < ActiveRecord::TestCase
+  fixtures :posts, :comments, :authors, :essays, :author_addresses, :categories, :categories_posts,
+            :companies, :accounts, :tags, :taggings, :people, :readers, :categorizations,
+            :owners, :pets, :author_favorites, :jobs, :references, :subscribers, :subscriptions, :books,
+            :developers, :projects, :developers_projects, :members, :memberships, :clubs, :sponsors
+
+  def test_eager_with_has_one_through_join_model_with_conditions_on_the_through
+    member = Member.all.merge!(:includes => :favourite_club).find(members(:some_other_guy).id)
+    assert_nil member.favourite_club
+  end
+
+  def test_loading_with_one_association
+    posts = Post.all.merge!(:includes => :comments).to_a
+    post = posts.find { |p| p.id == 1 }
+    assert_equal 2, post.comments.size
+    assert post.comments.include?(comments(:greetings))
+
+    post = Post.all.merge!(:includes => :comments, :where => "posts.title = 'Welcome to the weblog'").first
+    assert_equal 2, post.comments.size
+    assert post.comments.include?(comments(:greetings))
+
+    posts = Post.all.merge!(:includes => :last_comment).to_a
+    post = posts.find { |p| p.id == 1 }
+    assert_equal Post.find(1).last_comment, post.last_comment
+  end
+
+  def test_loading_with_one_association_with_non_preload
+    posts = Post.all.merge!(:includes => :last_comment, :order => 'comments.id DESC').to_a
+    post = posts.find { |p| p.id == 1 }
+    assert_equal Post.find(1).last_comment, post.last_comment
+  end
+
+  def test_loading_conditions_with_or
+    posts = authors(:david).posts.references(:comments).merge(
+      :includes => :comments,
+      :where => "comments.body like 'Normal%' OR comments.#{QUOTED_TYPE} = 'SpecialComment'"
+    ).to_a
+    assert_nil posts.detect { |p| p.author_id != authors(:david).id },
+      "expected to find only david's posts"
+  end
+
+  def test_with_ordering
+    list = Post.all.merge!(:includes => :comments, :order => "posts.id DESC").to_a
+    [:other_by_mary, :other_by_bob, :misc_by_mary, :misc_by_bob, :eager_other,
+     :sti_habtm, :sti_post_and_comments, :sti_comments, :authorless, :thinking, :welcome
+    ].each_with_index do |post, index|
+      assert_equal posts(post), list[index]
+    end
+  end
+
+  def test_has_many_through_with_order
+    authors = Author.includes(:favorite_authors).to_a
+    assert_no_queries { authors.map(&:favorite_authors) }
+  end
+
+  def test_with_two_tables_in_from_without_getting_double_quoted
+    posts = Post.select("posts.*").from("authors, posts").eager_load(:comments).where("posts.author_id = authors.id").order("posts.id").to_a
+    assert_equal 2, posts.first.comments.size
+  end
+
+  def test_loading_with_multiple_associations
+    posts = Post.all.merge!(:includes => [ :comments, :author, :categories ], :order => "posts.id").to_a
+    assert_equal 2, posts.first.comments.size
+    assert_equal 2, posts.first.categories.size
+    assert posts.first.comments.include?(comments(:greetings))
+  end
+
+  def test_duplicate_middle_objects
+    comments = Comment.all.merge!(:where => 'post_id = 1', :includes => [:post => :author]).to_a
+    assert_no_queries do
+      comments.each {|comment| comment.post.author.name}
+    end
+  end
+
+  def test_preloading_has_many_in_multiple_queries_with_more_ids_than_database_can_handle
+    Comment.connection.expects(:in_clause_length).at_least_once.returns(5)
+    posts = Post.all.merge!(:includes=>:comments).to_a
+    assert_equal 11, posts.size
+  end
+
+  def test_preloading_has_many_in_one_queries_when_database_has_no_limit_on_ids_it_can_handle
+    Comment.connection.expects(:in_clause_length).at_least_once.returns(nil)
+    posts = Post.all.merge!(:includes=>:comments).to_a
+    assert_equal 11, posts.size
+  end
+
+  def test_preloading_habtm_in_multiple_queries_with_more_ids_than_database_can_handle
+    Comment.connection.expects(:in_clause_length).at_least_once.returns(5)
+    posts = Post.all.merge!(:includes=>:categories).to_a
+    assert_equal 11, posts.size
+  end
+
+  def test_preloading_habtm_in_one_queries_when_database_has_no_limit_on_ids_it_can_handle
+    Comment.connection.expects(:in_clause_length).at_least_once.returns(nil)
+    posts = Post.all.merge!(:includes=>:categories).to_a
+    assert_equal 11, posts.size
+  end
+
+  def test_load_associated_records_in_one_query_when_adapter_has_no_limit
+    Comment.connection.expects(:in_clause_length).at_least_once.returns(nil)
+
+    post = posts(:welcome)
+    assert_queries(2) do
+      Post.includes(:comments).where(:id => post.id).to_a
+    end
+  end
+
+  def test_load_associated_records_in_several_queries_when_many_ids_passed
+    Comment.connection.expects(:in_clause_length).at_least_once.returns(1)
+
+    post1, post2 = posts(:welcome), posts(:thinking)
+    assert_queries(3) do
+      Post.includes(:comments).where(:id => [post1.id, post2.id]).to_a
+    end
+  end
+
+  def test_load_associated_records_in_one_query_when_a_few_ids_passed
+    Comment.connection.expects(:in_clause_length).at_least_once.returns(3)
+
+    post = posts(:welcome)
+    assert_queries(2) do
+      Post.includes(:comments).where(:id => post.id).to_a
+    end
+  end
+
+  def test_including_duplicate_objects_from_belongs_to
+    popular_post = Post.create!(:title => 'foo', :body => "I like cars!")
+    comment = popular_post.comments.create!(:body => "lol")
+    popular_post.readers.create!(:person => people(:michael))
+    popular_post.readers.create!(:person => people(:david))
+
+    readers = Reader.all.merge!(:where => ["post_id = ?", popular_post.id],
+                                :includes => {:post => :comments}).to_a
+    readers.each do |reader|
+      assert_equal [comment], reader.post.comments
+    end
+  end
+
+  def test_including_duplicate_objects_from_has_many
+    car_post = Post.create!(:title => 'foo', :body => "I like cars!")
+    car_post.categories << categories(:general)
+    car_post.categories << categories(:technology)
+
+    comment = car_post.comments.create!(:body => "hmm")
+    categories = Category.all.merge!(:where => { 'posts.id' => car_post.id },
+                                 :includes => {:posts => :comments}).to_a
+    categories.each do |category|
+      assert_equal [comment], category.posts[0].comments
+    end
+  end
+
+  def test_associations_loaded_for_all_records
+    post = Post.create!(:title => 'foo', :body => "I like cars!")
+    SpecialComment.create!(:body => 'Come on!', :post => post)
+    first_category = Category.create! :name => 'First!', :posts => [post]
+    second_category = Category.create! :name => 'Second!', :posts => [post]
+
+    categories = Category.where(:id => [first_category.id, second_category.id]).includes(:posts => :special_comments)
+    assert_equal categories.map { |category| category.posts.first.special_comments.loaded? }, [true, true]
+  end
+
+  def test_finding_with_includes_on_has_many_association_with_same_include_includes_only_once
+    author_id = authors(:david).id
+    author = assert_queries(3) { Author.all.merge!(:includes => {:posts_with_comments => :comments}).find(author_id) } # find the author, then find the posts, then find the comments
+    author.posts_with_comments.each do |post_with_comments|
+      assert_equal post_with_comments.comments.length, post_with_comments.comments.count
+      assert_nil post_with_comments.comments.to_a.uniq!
+    end
+  end
+
+  def test_finding_with_includes_on_has_one_association_with_same_include_includes_only_once
+    author = authors(:david)
+    post = author.post_about_thinking_with_last_comment
+    last_comment = post.last_comment
+    author = assert_queries(3) { Author.all.merge!(:includes => {:post_about_thinking_with_last_comment => :last_comment}).find(author.id)} # find the author, then find the posts, then find the comments
+    assert_no_queries do
+      assert_equal post, author.post_about_thinking_with_last_comment
+      assert_equal last_comment, author.post_about_thinking_with_last_comment.last_comment
+    end
+  end
+
+  def test_finding_with_includes_on_belongs_to_association_with_same_include_includes_only_once
+    post = posts(:welcome)
+    author = post.author
+    author_address = author.author_address
+    post = assert_queries(3) { Post.all.merge!(:includes => {:author_with_address => :author_address}).find(post.id) } # find the post, then find the author, then find the address
+    assert_no_queries do
+      assert_equal author, post.author_with_address
+      assert_equal author_address, post.author_with_address.author_address
+    end
+  end
+
+  def test_finding_with_includes_on_null_belongs_to_association_with_same_include_includes_only_once
+    post = posts(:welcome)
+    post.update!(author: nil)
+    post = assert_queries(1) { Post.all.merge!(includes: {author_with_address: :author_address}).find(post.id) }
+    # find the post, then find the author which is null so no query for the author or address
+    assert_no_queries do
+      assert_equal nil, post.author_with_address
+    end
+  end
+
+  def test_finding_with_includes_on_null_belongs_to_polymorphic_association
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    sponsor.update!(sponsorable: nil)
+    sponsor = assert_queries(1) { Sponsor.all.merge!(:includes => :sponsorable).find(sponsor.id) }
+    assert_no_queries do
+      assert_equal nil, sponsor.sponsorable
+    end
+  end
+
+  def test_finding_with_includes_on_empty_polymorphic_type_column
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    sponsor.update!(sponsorable_type: '', sponsorable_id: nil) # sponsorable_type column might be declared NOT NULL
+    sponsor = assert_queries(1) do
+      assert_nothing_raised { Sponsor.all.merge!(:includes => :sponsorable).find(sponsor.id) }
+    end
+    assert_no_queries do
+      assert_equal nil, sponsor.sponsorable
+    end
+  end
+
+  def test_loading_from_an_association
+    posts = authors(:david).posts.merge(:includes => :comments, :order => "posts.id").to_a
+    assert_equal 2, posts.first.comments.size
+  end
+
+  def test_loading_from_an_association_that_has_a_hash_of_conditions
+    assert_nothing_raised do
+      Author.all.merge!(:includes => :hello_posts_with_hash_conditions).to_a
+    end
+    assert !Author.all.merge!(:includes => :hello_posts_with_hash_conditions).find(authors(:david).id).hello_posts.empty?
+  end
+
+  def test_loading_with_no_associations
+    assert_nil Post.all.merge!(:includes => :author).find(posts(:authorless).id).author
+  end
+
+  # Regression test for 21c75e5
+  def test_nested_loading_does_not_raise_exception_when_association_does_not_exist
+    assert_nothing_raised do
+      Post.all.merge!(:includes => {:author => :author_addresss}).find(posts(:authorless).id)
+    end
+  end
+
+  def test_nested_loading_through_has_one_association
+    aa = AuthorAddress.all.merge!(:includes => {:author => :posts}).find(author_addresses(:david_address).id)
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order
+    aa = AuthorAddress.all.merge!(:includes => {:author => :posts}, :order => 'author_addresses.id').find(author_addresses(:david_address).id)
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order_on_association
+    aa = AuthorAddress.all.merge!(:includes => {:author => :posts}, :order => 'authors.id').find(author_addresses(:david_address).id)
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order_on_nested_association
+    aa = AuthorAddress.all.merge!(:includes => {:author => :posts}, :order => 'posts.id').find(author_addresses(:david_address).id)
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions
+    aa = AuthorAddress.references(:author_addresses).merge(
+      :includes => {:author => :posts},
+      :where => "author_addresses.id > 0"
+    ).find author_addresses(:david_address).id
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions_on_association
+    aa = AuthorAddress.references(:authors).merge(
+      :includes => {:author => :posts},
+      :where => "authors.id > 0"
+    ).find author_addresses(:david_address).id
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions_on_nested_association
+    aa = AuthorAddress.references(:posts).merge(
+      :includes => {:author => :posts},
+      :where => "posts.id > 0"
+    ).find author_addresses(:david_address).id
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_foreign_keys
+    pets = Pet.all.merge!(:includes => :owner).to_a
+    assert_equal 4, pets.length
+  end
+
+  def test_eager_association_loading_with_belongs_to
+    comments = Comment.all.merge!(:includes => :post).to_a
+    assert_equal 11, comments.length
+    titles = comments.map { |c| c.post.title }
+    assert titles.include?(posts(:welcome).title)
+    assert titles.include?(posts(:sti_post_and_comments).title)
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit
+    comments = Comment.all.merge!(:includes => :post, :limit => 5, :order => 'comments.id').to_a
+    assert_equal 5, comments.length
+    assert_equal [1,2,3,5,6], comments.collect { |c| c.id }
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_conditions
+    comments = Comment.all.merge!(:includes => :post, :where => 'post_id = 4', :limit => 3, :order => 'comments.id').to_a
+    assert_equal 3, comments.length
+    assert_equal [5,6,7], comments.collect { |c| c.id }
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_offset
+    comments = Comment.all.merge!(:includes => :post, :limit => 3, :offset => 2, :order => 'comments.id').to_a
+    assert_equal 3, comments.length
+    assert_equal [3,5,6], comments.collect { |c| c.id }
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_offset_and_conditions
+    comments = Comment.all.merge!(:includes => :post, :where => 'post_id = 4', :limit => 3, :offset => 1, :order => 'comments.id').to_a
+    assert_equal 3, comments.length
+    assert_equal [6,7,8], comments.collect { |c| c.id }
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_offset_and_conditions_array
+    comments = Comment.all.merge!(:includes => :post, :where => ['post_id = ?',4], :limit => 3, :offset => 1, :order => 'comments.id').to_a
+    assert_equal 3, comments.length
+    assert_equal [6,7,8], comments.collect { |c| c.id }
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_conditions_string_with_unquoted_table_name
+    assert_nothing_raised do
+      Comment.includes(:post).references(:posts).where('posts.id = ?', 4)
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_conditions_hash
+    comments = []
+    assert_nothing_raised do
+      comments = Comment.all.merge!(:includes => :post, :where => {:posts => {:id => 4}}, :limit => 3, :order => 'comments.id').to_a
+    end
+    assert_equal 3, comments.length
+    assert_equal [5,6,7], comments.collect { |c| c.id }
+    assert_no_queries do
+      comments.first.post
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_conditions_string_with_quoted_table_name
+    quoted_posts_id= Comment.connection.quote_table_name('posts') + '.' + Comment.connection.quote_column_name('id')
+    assert_nothing_raised do
+      Comment.includes(:post).references(:posts).where("#{quoted_posts_id} = ?", 4)
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_order_string_with_unquoted_table_name
+    assert_nothing_raised do
+      Comment.all.merge!(:includes => :post, :order => 'posts.id').to_a
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_order_string_with_quoted_table_name
+    quoted_posts_id= Comment.connection.quote_table_name('posts') + '.' + Comment.connection.quote_column_name('id')
+    assert_nothing_raised do
+      Comment.includes(:post).references(:posts).order(quoted_posts_id)
+    end
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_multiple_associations
+    posts = Post.all.merge!(:includes => [:author, :very_special_comment], :limit => 1, :order => 'posts.id').to_a
+    assert_equal 1, posts.length
+    assert_equal [1], posts.collect { |p| p.id }
+  end
+
+  def test_eager_association_loading_with_belongs_to_and_limit_and_offset_and_multiple_associations
+    posts = Post.all.merge!(:includes => [:author, :very_special_comment], :limit => 1, :offset => 1, :order => 'posts.id').to_a
+    assert_equal 1, posts.length
+    assert_equal [2], posts.collect { |p| p.id }
+  end
+
+  def test_eager_association_loading_with_belongs_to_inferred_foreign_key_from_association_name
+    author_favorite = AuthorFavorite.all.merge!(:includes => :favorite_author).first
+    assert_equal authors(:mary), assert_no_queries { author_favorite.favorite_author }
+  end
+
+  def test_eager_load_belongs_to_quotes_table_and_column_names
+    job = Job.includes(:ideal_reference).find jobs(:unicyclist).id
+    references(:michael_unicyclist)
+    assert_no_queries{ assert_equal references(:michael_unicyclist), job.ideal_reference}
+  end
+
+  def test_eager_load_has_one_quotes_table_and_column_names
+    michael = Person.all.merge!(:includes => :favourite_reference).find(people(:michael).id)
+    references(:michael_unicyclist)
+    assert_no_queries{ assert_equal references(:michael_unicyclist), michael.favourite_reference}
+  end
+
+  def test_eager_load_has_many_quotes_table_and_column_names
+    michael = Person.all.merge!(:includes => :references).find(people(:michael).id)
+    references(:michael_magician,:michael_unicyclist)
+    assert_no_queries{ assert_equal references(:michael_magician,:michael_unicyclist), michael.references.sort_by(&:id) }
+  end
+
+  def test_eager_load_has_many_through_quotes_table_and_column_names
+    michael = Person.all.merge!(:includes => :jobs).find(people(:michael).id)
+    jobs(:magician, :unicyclist)
+    assert_no_queries{ assert_equal jobs(:unicyclist, :magician), michael.jobs.sort_by(&:id) }
+  end
+
+  def test_eager_load_has_many_with_string_keys
+    subscriptions = subscriptions(:webster_awdr, :webster_rfr)
+    subscriber =Subscriber.all.merge!(:includes => :subscriptions).find(subscribers(:second).id)
+    assert_equal subscriptions, subscriber.subscriptions.sort_by(&:id)
+  end
+
+  def test_string_id_column_joins
+    s = Subscriber.create! do |c|
+      c.id = "PL"
+    end
+
+    b = Book.create!
+
+    Subscription.create!(:subscriber_id => "PL", :book_id => b.id)
+    s.reload
+    s.book_ids = s.book_ids
+  end
+
+  def test_eager_load_has_many_through_with_string_keys
+    books = books(:awdr, :rfr)
+    subscriber = Subscriber.all.merge!(:includes => :books).find(subscribers(:second).id)
+    assert_equal books, subscriber.books.sort_by(&:id)
+  end
+
+  def test_eager_load_belongs_to_with_string_keys
+    subscriber = subscribers(:second)
+    subscription = Subscription.all.merge!(:includes => :subscriber).find(subscriptions(:webster_awdr).id)
+    assert_equal subscriber, subscription.subscriber
+  end
+
+  def test_eager_association_loading_with_explicit_join
+    posts = Post.all.merge!(:includes => :comments, :joins => "INNER JOIN authors ON posts.author_id = authors.id AND authors.name = 'Mary'", :limit => 1, :order => 'author_id').to_a
+    assert_equal 1, posts.length
+  end
+
+  def test_eager_with_has_many_through
+    posts_with_comments = people(:michael).posts.merge(:includes => :comments, :order => 'posts.id').to_a
+    posts_with_author = people(:michael).posts.merge(:includes => :author, :order => 'posts.id').to_a
+    posts_with_comments_and_author = people(:michael).posts.merge(:includes => [ :comments, :author ], :order => 'posts.id').to_a
+    assert_equal 2, posts_with_comments.inject(0) { |sum, post| sum + post.comments.size }
+    assert_equal authors(:david), assert_no_queries { posts_with_author.first.author }
+    assert_equal authors(:david), assert_no_queries { posts_with_comments_and_author.first.author }
+  end
+
+  def test_eager_with_has_many_through_a_belongs_to_association
+    author = authors(:mary)
+    Post.create!(:author => author, :title => "TITLE", :body => "BODY")
+    author.author_favorites.create(:favorite_author_id => 1)
+    author.author_favorites.create(:favorite_author_id => 2)
+    posts_with_author_favorites = author.posts.merge(:includes => :author_favorites).to_a
+    assert_no_queries { posts_with_author_favorites.first.author_favorites.first.author_id }
+  end
+
+  def test_eager_with_has_many_through_an_sti_join_model
+    author = Author.all.merge!(:includes => :special_post_comments, :order => 'authors.id').first
+    assert_equal [comments(:does_it_hurt)], assert_no_queries { author.special_post_comments }
+  end
+
+  def test_eager_with_has_many_through_an_sti_join_model_with_conditions_on_both
+    author = Author.all.merge!(:includes => :special_nonexistant_post_comments, :order => 'authors.id').first
+    assert_equal [], author.special_nonexistant_post_comments
+  end
+
+  def test_eager_with_has_many_through_join_model_with_conditions
+    assert_equal Author.all.merge!(:includes => :hello_post_comments,
+                             :order => 'authors.id').first.hello_post_comments.sort_by(&:id),
+                 Author.all.merge!(:order => 'authors.id').first.hello_post_comments.sort_by(&:id)
+  end
+
+  def test_eager_with_has_many_through_join_model_with_conditions_on_top_level
+    assert_equal comments(:more_greetings), Author.all.merge!(:includes => :comments_with_order_and_conditions).find(authors(:david).id).comments_with_order_and_conditions.first
+  end
+
+  def test_eager_with_has_many_through_join_model_with_include
+    author_comments = Author.all.merge!(:includes => :comments_with_include).find(authors(:david).id).comments_with_include.to_a
+    assert_no_queries do
+      author_comments.first.post.title
+    end
+  end
+
+  def test_eager_with_has_many_through_with_conditions_join_model_with_include
+    post_tags = Post.find(posts(:welcome).id).misc_tags
+    eager_post_tags = Post.all.merge!(:includes => :misc_tags).find(1).misc_tags
+    assert_equal post_tags, eager_post_tags
+  end
+
+  def test_eager_with_has_many_through_join_model_ignores_default_includes
+    assert_nothing_raised do
+      authors(:david).comments_on_posts_with_default_include.to_a
+    end
+  end
+
+  def test_eager_with_has_many_and_limit
+    posts = Post.all.merge!(:order => 'posts.id asc', :includes => [ :author, :comments ], :limit => 2).to_a
+    assert_equal 2, posts.size
+    assert_equal 3, posts.inject(0) { |sum, post| sum + post.comments.size }
+  end
+
+  def test_eager_with_has_many_and_limit_and_conditions
+    posts = Post.all.merge!(:includes => [ :author, :comments ], :limit => 2, :where => "posts.body = 'hello'", :order => "posts.id").to_a
+    assert_equal 2, posts.size
+    assert_equal [4,5], posts.collect { |p| p.id }
+  end
+
+  def test_eager_with_has_many_and_limit_and_conditions_array
+    posts = Post.all.merge!(:includes => [ :author, :comments ], :limit => 2, :where => [ "posts.body = ?", 'hello' ], :order => "posts.id").to_a
+    assert_equal 2, posts.size
+    assert_equal [4,5], posts.collect { |p| p.id }
+  end
+
+  def test_eager_with_has_many_and_limit_and_conditions_array_on_the_eagers
+    posts = Post.includes(:author, :comments).limit(2).references(:author).where("authors.name = ?", 'David')
+    assert_equal 2, posts.size
+
+    count = Post.includes(:author, :comments).limit(2).references(:author).where("authors.name = ?", 'David').count
+    assert_equal posts.size, count
+  end
+
+  def test_eager_with_has_many_and_limit_and_high_offset
+    posts = Post.all.merge!(:includes => [ :author, :comments ], :limit => 2, :offset => 10, :where => { 'authors.name' => 'David' }).to_a
+    assert_equal 0, posts.size
+  end
+
+  def test_eager_with_has_many_and_limit_and_high_offset_and_multiple_array_conditions
+    assert_queries(1) do
+      posts = Post.references(:authors, :comments).
+        merge(:includes => [ :author, :comments ], :limit => 2, :offset => 10,
+          :where => [ "authors.name = ? and comments.body = ?", 'David', 'go crazy' ]).to_a
+      assert_equal 0, posts.size
+    end
+  end
+
+  def test_eager_with_has_many_and_limit_and_high_offset_and_multiple_hash_conditions
+    assert_queries(1) do
+      posts = Post.all.merge!(:includes => [ :author, :comments ], :limit => 2, :offset => 10,
+        :where => { 'authors.name' => 'David', 'comments.body' => 'go crazy' }).to_a
+      assert_equal 0, posts.size
+    end
+  end
+
+  def test_count_eager_with_has_many_and_limit_and_high_offset
+    posts = Post.all.merge!(:includes => [ :author, :comments ], :limit => 2, :offset => 10, :where => { 'authors.name' => 'David' }).count(:all)
+    assert_equal 0, posts
+  end
+
+  def test_eager_with_has_many_and_limit_with_no_results
+    posts = Post.all.merge!(:includes => [ :author, :comments ], :limit => 2, :where => "posts.title = 'magic forest'").to_a
+    assert_equal 0, posts.size
+  end
+
+  def test_eager_count_performed_on_a_has_many_association_with_multi_table_conditional
+    author = authors(:david)
+    author_posts_without_comments = author.posts.select { |post| post.comments.blank? }
+    assert_equal author_posts_without_comments.size, author.posts.includes(:comments).where('comments.id is null').references(:comments).count
+  end
+
+  def test_eager_count_performed_on_a_has_many_through_association_with_multi_table_conditional
+    person = people(:michael)
+    person_posts_without_comments = person.posts.select { |post| post.comments.blank? }
+    assert_equal person_posts_without_comments.size, person.posts_with_no_comments.count
+  end
+
+  def test_eager_with_has_and_belongs_to_many_and_limit
+    posts = Post.all.merge!(:includes => :categories, :order => "posts.id", :limit => 3).to_a
+    assert_equal 3, posts.size
+    assert_equal 2, posts[0].categories.size
+    assert_equal 1, posts[1].categories.size
+    assert_equal 0, posts[2].categories.size
+    assert posts[0].categories.include?(categories(:technology))
+    assert posts[1].categories.include?(categories(:general))
+  end
+
+  # Since the preloader for habtm gets raw row hashes from the database and then
+  # instantiates them, this test ensures that it only instantiates one actual
+  # object per record from the database.
+  def test_has_and_belongs_to_many_should_not_instantiate_same_records_multiple_times
+    welcome    = posts(:welcome)
+    categories = Category.includes(:posts)
+
+    general    = categories.find { |c| c == categories(:general) }
+    technology = categories.find { |c| c == categories(:technology) }
+
+    post1 = general.posts.to_a.find { |p| p == welcome }
+    post2 = technology.posts.to_a.find { |p| p == welcome }
+
+    assert_equal post1.object_id, post2.object_id
+  end
+
+  def test_eager_with_has_many_and_limit_and_conditions_on_the_eagers
+    posts =
+      authors(:david).posts
+        .includes(:comments)
+        .where("comments.body like 'Normal%' OR comments.#{QUOTED_TYPE}= 'SpecialComment'")
+        .references(:comments)
+        .limit(2)
+        .to_a
+    assert_equal 2, posts.size
+
+    count =
+      Post.includes(:comments, :author)
+        .where("authors.name = 'David' AND (comments.body like 'Normal%' OR comments.#{QUOTED_TYPE}= 'SpecialComment')")
+        .references(:authors, :comments)
+        .limit(2)
+        .count
+    assert_equal count, posts.size
+  end
+
+  def test_eager_with_has_many_and_limit_and_scoped_conditions_on_the_eagers
+    posts = nil
+    Post.includes(:comments)
+      .where("comments.body like 'Normal%' OR comments.#{QUOTED_TYPE}= 'SpecialComment'")
+      .references(:comments)
+      .scoping do
+
+      posts = authors(:david).posts.limit(2).to_a
+      assert_equal 2, posts.size
+    end
+
+    Post.includes(:comments, :author)
+      .where("authors.name = 'David' AND (comments.body like 'Normal%' OR comments.#{QUOTED_TYPE}= 'SpecialComment')")
+      .references(:authors, :comments)
+      .scoping do
+
+      count = Post.limit(2).count
+      assert_equal count, posts.size
+    end
+  end
+
+  def test_eager_association_loading_with_habtm
+    posts = Post.all.merge!(:includes => :categories, :order => "posts.id").to_a
+    assert_equal 2, posts[0].categories.size
+    assert_equal 1, posts[1].categories.size
+    assert_equal 0, posts[2].categories.size
+    assert posts[0].categories.include?(categories(:technology))
+    assert posts[1].categories.include?(categories(:general))
+  end
+
+  def test_eager_with_inheritance
+    SpecialPost.all.merge!(:includes => [ :comments ]).to_a
+  end
+
+  def test_eager_has_one_with_association_inheritance
+    post = Post.all.merge!(:includes => [ :very_special_comment ]).find(4)
+    assert_equal "VerySpecialComment", post.very_special_comment.class.to_s
+  end
+
+  def test_eager_has_many_with_association_inheritance
+    post = Post.all.merge!(:includes => [ :special_comments ]).find(4)
+    post.special_comments.each do |special_comment|
+      assert special_comment.is_a?(SpecialComment)
+    end
+  end
+
+  def test_eager_habtm_with_association_inheritance
+    post = Post.all.merge!(:includes => [ :special_categories ]).find(6)
+    assert_equal 1, post.special_categories.size
+    post.special_categories.each do |special_category|
+      assert_equal "SpecialCategory", special_category.class.to_s
+    end
+  end
+
+  def test_eager_with_has_one_dependent_does_not_destroy_dependent
+    assert_not_nil companies(:first_firm).account
+    f = Firm.all.merge!(:includes => :account,
+            :where => ["companies.name = ?", "37signals"]).first
+    assert_not_nil f.account
+    assert_equal companies(:first_firm, :reload).account, f.account
+  end
+
+  def test_eager_with_multi_table_conditional_properly_counts_the_records_when_using_size
+    author = authors(:david)
+    posts_with_no_comments = author.posts.select { |post| post.comments.blank? }
+    assert_equal posts_with_no_comments.size, author.posts_with_no_comments.size
+    assert_equal posts_with_no_comments, author.posts_with_no_comments
+  end
+
+  def test_eager_with_invalid_association_reference
+    assert_raise(ActiveRecord::AssociationNotFoundError, "Association was not found; perhaps you misspelled it?  You specified :include => :monkeys") {
+      Post.all.merge!(:includes=> :monkeys ).find(6)
+    }
+    assert_raise(ActiveRecord::AssociationNotFoundError, "Association was not found; perhaps you misspelled it?  You specified :include => :monkeys") {
+      Post.all.merge!(:includes=>[ :monkeys ]).find(6)
+    }
+    assert_raise(ActiveRecord::AssociationNotFoundError, "Association was not found; perhaps you misspelled it?  You specified :include => :monkeys") {
+      Post.all.merge!(:includes=>[ 'monkeys' ]).find(6)
+    }
+    assert_raise(ActiveRecord::AssociationNotFoundError, "Association was not found; perhaps you misspelled it?  You specified :include => :monkeys, :elephants") {
+      Post.all.merge!(:includes=>[ :monkeys, :elephants ]).find(6)
+    }
+  end
+
+  def test_eager_with_default_scope
+    developer = EagerDeveloperWithDefaultScope.where(:name => 'David').first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_class_method
+    developer = EagerDeveloperWithClassMethodDefaultScope.where(:name => 'David').first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_lambda
+    developer = EagerDeveloperWithLambdaDefaultScope.where(:name => 'David').first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_block
+    # warm up the habtm cache
+    EagerDeveloperWithBlockDefaultScope.where(:name => 'David').first.projects
+    developer = EagerDeveloperWithBlockDefaultScope.where(:name => 'David').first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def test_eager_with_default_scope_as_callable
+    developer = EagerDeveloperWithCallableDefaultScope.where(:name => 'David').first
+    projects = Project.order(:id).to_a
+    assert_no_queries do
+      assert_equal(projects, developer.projects)
+    end
+  end
+
+  def find_all_ordered(className, include=nil)
+    className.all.merge!(:order=>"#{className.table_name}.#{className.primary_key}", :includes=>include).to_a
+  end
+
+  def test_limited_eager_with_order
+    assert_equal(
+      posts(:thinking, :sti_comments),
+      Post.all.merge!(
+        :includes => [:author, :comments], :where => { 'authors.name' => 'David' },
+        :order => 'UPPER(posts.title)', :limit => 2, :offset => 1
+      ).to_a
+    )
+    assert_equal(
+      posts(:sti_post_and_comments, :sti_comments),
+      Post.all.merge!(
+        :includes => [:author, :comments], :where => { 'authors.name' => 'David' },
+        :order => 'UPPER(posts.title) DESC', :limit => 2, :offset => 1
+      ).to_a
+    )
+  end
+
+  def test_limited_eager_with_multiple_order_columns
+    assert_equal(
+      posts(:thinking, :sti_comments),
+      Post.all.merge!(
+        :includes => [:author, :comments], :where => { 'authors.name' => 'David' },
+        :order => ['UPPER(posts.title)', 'posts.id'], :limit => 2, :offset => 1
+      ).to_a
+    )
+    assert_equal(
+      posts(:sti_post_and_comments, :sti_comments),
+      Post.all.merge!(
+        :includes => [:author, :comments], :where => { 'authors.name' => 'David' },
+        :order => ['UPPER(posts.title) DESC', 'posts.id'], :limit => 2, :offset => 1
+      ).to_a
+    )
+  end
+
+  def test_limited_eager_with_numeric_in_association
+    assert_equal(
+      people(:david, :susan),
+      Person.references(:number1_fans_people).merge(
+        :includes => [:readers, :primary_contact, :number1_fan],
+        :where => "number1_fans_people.first_name like 'M%'",
+        :order => 'people.id', :limit => 2, :offset => 0
+      ).to_a
+    )
+  end
+
+  def test_preload_with_interpolation
+    assert_deprecated do
+      post = Post.includes(:comments_with_interpolated_conditions).find(posts(:welcome).id)
+      assert_equal [comments(:greetings)], post.comments_with_interpolated_conditions
+    end
+
+    assert_deprecated do
+      post = Post.joins(:comments_with_interpolated_conditions).find(posts(:welcome).id)
+      assert_equal [comments(:greetings)], post.comments_with_interpolated_conditions
+    end
+  end
+
+  def test_polymorphic_type_condition
+    post = Post.all.merge!(:includes => :taggings).find(posts(:thinking).id)
+    assert post.taggings.include?(taggings(:thinking_general))
+    post = SpecialPost.all.merge!(:includes => :taggings).find(posts(:thinking).id)
+    assert post.taggings.include?(taggings(:thinking_general))
+  end
+
+  def test_eager_with_multiple_associations_with_same_table_has_many_and_habtm
+    # Eager includes of has many and habtm associations aren't necessarily sorted in the same way
+    def assert_equal_after_sort(item1, item2, item3 = nil)
+      assert_equal(item1.sort{|a,b| a.id <=> b.id}, item2.sort{|a,b| a.id <=> b.id})
+      assert_equal(item3.sort{|a,b| a.id <=> b.id}, item2.sort{|a,b| a.id <=> b.id}) if item3
+    end
+    # Test regular association, association with conditions, association with
+    # STI, and association with conditions assured not to be true
+    post_types = [:posts, :other_posts, :special_posts]
+    # test both has_many and has_and_belongs_to_many
+    [Author, Category].each do |className|
+      d1 = find_all_ordered(className)
+      # test including all post types at once
+      d2 = find_all_ordered(className, post_types)
+      d1.each_index do |i|
+        assert_equal(d1[i], d2[i])
+        assert_equal_after_sort(d1[i].posts, d2[i].posts)
+        post_types[1..-1].each do |post_type|
+          # test including post_types together
+          d3 = find_all_ordered(className, [:posts, post_type])
+          assert_equal(d1[i], d3[i])
+          assert_equal_after_sort(d1[i].posts, d3[i].posts)
+          assert_equal_after_sort(d1[i].send(post_type), d2[i].send(post_type), d3[i].send(post_type))
+        end
+      end
+    end
+  end
+
+  def test_eager_with_multiple_associations_with_same_table_has_one
+    d1 = find_all_ordered(Firm)
+    d2 = find_all_ordered(Firm, :account)
+    d1.each_index do |i|
+      assert_equal(d1[i], d2[i])
+      assert_equal(d1[i].account, d2[i].account)
+    end
+  end
+
+  def test_eager_with_multiple_associations_with_same_table_belongs_to
+    firm_types = [:firm, :firm_with_basic_id, :firm_with_other_name, :firm_with_condition]
+    d1 = find_all_ordered(Client)
+    d2 = find_all_ordered(Client, firm_types)
+    d1.each_index do |i|
+      assert_equal(d1[i], d2[i])
+      firm_types.each { |type| assert_equal(d1[i].send(type), d2[i].send(type)) }
+    end
+  end
+  def test_eager_with_valid_association_as_string_not_symbol
+    assert_nothing_raised { Post.all.merge!(:includes => 'comments').to_a }
+  end
+
+  def test_eager_with_floating_point_numbers
+    assert_queries(2) do
+      # Before changes, the floating point numbers will be interpreted as table names and will cause this to run in one query
+      Comment.all.merge!(:where => "123.456 = 123.456", :includes => :post).to_a
+    end
+  end
+
+  def test_preconfigured_includes_with_belongs_to
+    author = posts(:welcome).author_with_posts
+    assert_no_queries {assert_equal 5, author.posts.size}
+  end
+
+  def test_preconfigured_includes_with_has_one
+    comment = posts(:sti_comments).very_special_comment_with_post
+    assert_no_queries {assert_equal posts(:sti_comments), comment.post}
+  end
+
+  def test_preconfigured_includes_with_has_many
+    posts = authors(:david).posts_with_comments
+    one = posts.detect { |p| p.id == 1 }
+    assert_no_queries do
+      assert_equal 5, posts.size
+      assert_equal 2, one.comments.size
+    end
+  end
+
+  def test_preconfigured_includes_with_habtm
+    posts = authors(:david).posts_with_categories
+    one = posts.detect { |p| p.id == 1 }
+    assert_no_queries do
+      assert_equal 5, posts.size
+      assert_equal 2, one.categories.size
+    end
+  end
+
+  def test_preconfigured_includes_with_has_many_and_habtm
+    posts = authors(:david).posts_with_comments_and_categories
+    one = posts.detect { |p| p.id == 1 }
+    assert_no_queries do
+      assert_equal 5, posts.size
+      assert_equal 2, one.comments.size
+      assert_equal 2, one.categories.size
+    end
+  end
+
+  def test_count_with_include
+    assert_equal 3, authors(:david).posts_with_comments.where("length(comments.body) > 15").references(:comments).count
+  end
+
+  def test_load_with_sti_sharing_association
+    assert_queries(2) do #should not do 1 query per subclass
+      Comment.includes(:post).to_a
+    end
+  end
+
+  def test_conditions_on_join_table_with_include_and_limit
+    assert_equal 3, Developer.all.merge!(:includes => 'projects', :where => { 'developers_projects.access_level' => 1 }, :limit => 5).to_a.size
+  end
+
+  def test_dont_create_temporary_active_record_instances
+    Developer.instance_count = 0
+    developers = Developer.all.merge!(:includes => 'projects', :where => { 'developers_projects.access_level' => 1 }, :limit => 5).to_a
+    assert_equal developers.count, Developer.instance_count
+  end
+
+  def test_order_on_join_table_with_include_and_limit
+    assert_equal 5, Developer.all.merge!(:includes => 'projects', :order => 'developers_projects.joined_on DESC', :limit => 5).to_a.size
+  end
+
+  def test_eager_loading_with_order_on_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.all.merge!(:joins => :comments, :includes => :author, :order => 'comments.id DESC').to_a
+    end
+    assert_equal posts(:eager_other), posts[1]
+    assert_equal authors(:mary), assert_no_queries { posts[1].author}
+  end
+
+  def test_eager_loading_with_conditions_on_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.all.merge!(:select => 'distinct posts.*', :includes => :author, :joins => [:comments], :where => "comments.body like 'Thank you%'", :order => 'posts.id').to_a
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author}
+
+    posts = assert_queries(2) do
+      Post.all.merge!(:select => 'distinct posts.*', :includes => :author, :joins => [:comments], :where => "comments.body like 'Thank you%'", :order => 'posts.id').to_a
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author}
+
+    posts = assert_queries(2) do
+      Post.all.merge!(:includes => :author, :joins => {:taggings => :tag}, :where => "tags.name = 'General'", :order => 'posts.id').to_a
+    end
+    assert_equal posts(:welcome, :thinking), posts
+
+    posts = assert_queries(2) do
+      Post.all.merge!(:includes => :author, :joins => {:taggings => {:tag => :taggings}}, :where => "taggings_tags.super_tag_id=2", :order => 'posts.id').to_a
+    end
+    assert_equal posts(:welcome, :thinking), posts
+  end
+
+  def test_preload_has_many_with_association_condition_and_default_scope
+    post = Post.create!(:title => 'Beaches', :body => "I like beaches!")
+    Reader.create! :person => people(:david), :post => post
+    LazyReader.create! :person => people(:susan), :post => post
+
+    assert_equal 1, post.lazy_readers.to_a.size
+    assert_equal 2, post.lazy_readers_skimmers_or_not.to_a.size
+
+    post_with_readers = Post.includes(:lazy_readers_skimmers_or_not).find(post.id)
+    assert_equal 2, post_with_readers.lazy_readers_skimmers_or_not.to_a.size
+  end
+
+  def test_eager_loading_with_conditions_on_string_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.all.merge!(:select => 'distinct posts.*', :includes => :author, :joins => "INNER JOIN comments on comments.post_id = posts.id", :where => "comments.body like 'Thank you%'", :order => 'posts.id').to_a
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author}
+
+    posts = assert_queries(2) do
+      Post.all.merge!(:select => 'distinct posts.*', :includes => :author, :joins => ["INNER JOIN comments on comments.post_id = posts.id"], :where => "comments.body like 'Thank you%'", :order => 'posts.id').to_a
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author}
+  end
+
+  def test_eager_loading_with_select_on_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.all.merge!(:select => 'posts.*, authors.name as author_name', :includes => :comments, :joins => :author, :order => 'posts.id').to_a
+    end
+    assert_equal 'David', posts[0].author_name
+    assert_equal posts(:welcome).comments, assert_no_queries { posts[0].comments}
+  end
+
+  def test_eager_loading_with_conditions_on_join_model_preloads
+    authors = assert_queries(2) do
+      Author.all.merge!(:includes => :author_address, :joins => :comments, :where => "posts.title like 'Welcome%'").to_a
+    end
+    assert_equal authors(:david), authors[0]
+    assert_equal author_addresses(:david_address), authors[0].author_address
+  end
+
+  def test_preload_belongs_to_uses_exclusive_scope
+    people = Person.males.merge(:includes => :primary_contact).to_a
+    assert_not_equal people.length, 0
+    people.each do |person|
+      assert_no_queries {assert_not_nil person.primary_contact}
+      assert_equal Person.find(person.id).primary_contact, person.primary_contact
+    end
+  end
+
+  def test_preload_has_many_uses_exclusive_scope
+    people = Person.males.includes(:agents).to_a
+    people.each do |person|
+      assert_equal Person.find(person.id).agents, person.agents
+    end
+  end
+
+  def test_preload_has_many_using_primary_key
+    expected = Firm.first.clients_using_primary_key.to_a
+    firm = Firm.includes(:clients_using_primary_key).first
+    assert_no_queries do
+      assert_equal expected, firm.clients_using_primary_key
+    end
+  end
+
+  def test_include_has_many_using_primary_key
+    expected = Firm.find(1).clients_using_primary_key.sort_by(&:name)
+    # Oracle adapter truncates alias to 30 characters
+    if current_adapter?(:OracleAdapter)
+      firm = Firm.all.merge!(:includes => :clients_using_primary_key, :order => 'clients_using_primary_keys_companies'[0,30]+'.name').find(1)
+    else
+      firm = Firm.all.merge!(:includes => :clients_using_primary_key, :order => 'clients_using_primary_keys_companies.name').find(1)
+    end
+    assert_no_queries do
+      assert_equal expected, firm.clients_using_primary_key
+    end
+  end
+
+  def test_preload_has_one_using_primary_key
+    expected = accounts(:signals37)
+    firm = Firm.all.merge!(:includes => :account_using_primary_key, :order => 'companies.id').first
+    assert_no_queries do
+      assert_equal expected, firm.account_using_primary_key
+    end
+  end
+
+  def test_include_has_one_using_primary_key
+    expected = accounts(:signals37)
+    firm = Firm.all.merge!(:includes => :account_using_primary_key, :order => 'accounts.id').to_a.detect {|f| f.id == 1}
+    assert_no_queries do
+      assert_equal expected, firm.account_using_primary_key
+    end
+  end
+
+  def test_preloading_empty_belongs_to
+    c = Client.create!(:name => 'Foo', :client_of => Company.maximum(:id) + 1)
+
+    client = assert_queries(2) { Client.preload(:firm).find(c.id) }
+    assert_no_queries { assert_nil client.firm }
+  end
+
+  def test_preloading_empty_belongs_to_polymorphic
+    t = Tagging.create!(:taggable_type => 'Post', :taggable_id => Post.maximum(:id) + 1, :tag => tags(:general))
+
+    tagging = assert_queries(2) { Tagging.preload(:taggable).find(t.id) }
+    assert_no_queries { assert_nil tagging.taggable }
+  end
+
+  def test_preloading_through_empty_belongs_to
+    c = Client.create!(:name => 'Foo', :client_of => Company.maximum(:id) + 1)
+
+    client = assert_queries(2) { Client.preload(:accounts).find(c.id) }
+    assert_no_queries { assert client.accounts.empty? }
+  end
+
+  def test_preloading_has_many_through_with_uniq
+    mary = Author.includes(:unique_categorized_posts).where(:id => authors(:mary).id).first
+    assert_equal 1, mary.unique_categorized_posts.length
+    assert_equal 1, mary.unique_categorized_post_ids.length
+  end
+
+  def test_preloading_polymorphic_with_custom_foreign_type
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    groucho = members(:groucho)
+
+    sponsor = assert_queries(2) {
+      Sponsor.includes(:thing).where(:id => sponsor.id).first
+    }
+    assert_no_queries { assert_equal groucho, sponsor.thing }
+  end
+
+  def test_joins_with_includes_should_preload_via_joins
+    post = assert_queries(1) { Post.includes(:comments).joins(:comments).order('posts.id desc').to_a.first }
+
+    assert_queries(0) do
+      assert_not_equal 0, post.comments.to_a.count
+    end
+  end
+
+  def test_join_eager_with_empty_order_should_generate_valid_sql
+    assert_nothing_raised(ActiveRecord::StatementInvalid) do
+      Post.includes(:comments).order("").where(:comments => {:body => "Thank you for the welcome"}).first
+    end
+  end
+
+  def test_join_eager_with_nil_order_should_generate_valid_sql
+    assert_nothing_raised(ActiveRecord::StatementInvalid) do
+      Post.includes(:comments).order(nil).where(:comments => {:body => "Thank you for the welcome"}).first
+    end
+  end
+
+  def test_deep_including_through_habtm
+    # warm up habtm cache
+    posts = Post.all.merge!(:includes => {:categories => :categorizations}, :order => "posts.id").to_a
+    posts[0].categories[0].categorizations.length
+
+    posts = Post.all.merge!(:includes => {:categories => :categorizations}, :order => "posts.id").to_a
+    assert_no_queries { assert_equal 2, posts[0].categories[0].categorizations.length }
+    assert_no_queries { assert_equal 1, posts[0].categories[1].categorizations.length }
+    assert_no_queries { assert_equal 2, posts[1].categories[0].categorizations.length }
+  end
+
+  test "scoping with a circular preload" do
+    assert_equal Comment.find(1), Comment.preload(:post => :comments).scoping { Comment.find(1) }
+  end
+
+  test "circular preload does not modify unscoped" do
+    expected = FirstPost.unscoped.find(2)
+    FirstPost.preload(:comments => :first_post).find(1)
+    assert_equal expected, FirstPost.unscoped.find(2)
+  end
+
+  test "preload ignores the scoping" do
+    assert_equal(
+      Comment.find(1).post,
+      Post.where('1 = 0').scoping { Comment.preload(:post).find(1).post }
+    )
+  end
+
+  test "deep preload" do
+    post = Post.preload(author: :posts, comments: :post).first
+
+    assert_predicate post.author.association(:posts), :loaded?
+    assert_predicate post.comments.first.association(:post), :loaded?
+  end
+
+  test "preloading does not cache has many association subset when preloaded with a through association" do
+    author = Author.includes(:comments_with_order_and_conditions, :posts).first
+    assert_no_queries { assert_equal 2, author.comments_with_order_and_conditions.size }
+    assert_no_queries { assert_equal 5, author.posts.size, "should not cache a subset of the association" }
+  end
+
+  test "preloading a through association twice does not reset it" do
+    members = Member.includes(current_membership: :club).includes(:club).to_a
+    assert_no_queries {
+      assert_equal 3, members.map(&:current_membership).map(&:club).size
+    }
+  end
+
+  test "works in combination with order(:symbol) and reorder(:symbol)" do
+    author = Author.includes(:posts).references(:posts).order(:name).find_by('posts.title IS NOT NULL')
+    assert_equal authors(:bob), author
+
+    author = Author.includes(:posts).references(:posts).reorder(:name).find_by('posts.title IS NOT NULL')
+    assert_equal authors(:bob), author
+  end
+
+  test "preloading with a polymorphic association and using the existential predicate but also using a select" do
+    assert_equal authors(:david), authors(:david).essays.includes(:writer).first.writer
+
+    assert_nothing_raised do
+      authors(:david).essays.includes(:writer).select(:name).any?
+    end
+  end
+
+  test "preloading the same association twice works" do
+    Member.create!
+    members = Member.preload(:current_membership).includes(current_membership: :club).all.to_a
+    assert_no_queries {
+      members_with_membership = members.select(&:current_membership)
+      assert_equal 3, members_with_membership.map(&:current_membership).map(&:club).size
+    }
+  end
+
+  test "preloading with a polymorphic association and using the existential predicate" do
+    assert_equal authors(:david), authors(:david).essays.includes(:writer).first.writer
+
+    assert_nothing_raised do
+      authors(:david).essays.includes(:writer).any?
+    end
+  end
+
+  test "preloading associations with string joins and order references" do
+    author = assert_queries(2) {
+      Author.includes(:posts).joins("LEFT JOIN posts ON posts.author_id = authors.id").order("posts.title DESC").first
+    }
+    assert_no_queries {
+      assert_equal 5, author.posts.size
+    }
+  end
+
+  test "including associations with where.not adds implicit references" do
+    author = assert_queries(2) {
+      Author.includes(:posts).where.not(posts: { title: 'Welcome to the weblog'} ).last
+    }
+
+    assert_no_queries {
+      assert_equal 2, author.posts.size
+    }
+  end
+
+  test "including association based on sql condition and no database column" do
+    assert_equal pets(:parrot), Owner.including_last_pet.first.last_pet
+  end
+
+  test "include instance dependent associations is deprecated" do
+    message = "association scope 'posts_with_signature' is"
+    assert_deprecated message do
+      begin
+        Author.includes(:posts_with_signature).to_a
+      rescue NoMethodError
+        # it's expected that preloading of this association fails
+      end
+    end
+
+    assert_deprecated message do
+      Author.preload(:posts_with_signature).to_a rescue NoMethodError
+    end
+
+    assert_deprecated message do
+      Author.eager_load(:posts_with_signature).to_a
+    end
+  end
+
+  test "preloading readonly association" do
+    # has-one
+    firm = Firm.where(id: "1").preload(:readonly_account).first!
+    assert firm.readonly_account.readonly?
+
+    # has_and_belongs_to_many
+    project = Project.where(id: "2").preload(:readonly_developers).first!
+    assert project.readonly_developers.first.readonly?
+
+    # has-many :through
+    david = Author.where(id: "1").preload(:readonly_comments).first!
+    assert david.readonly_comments.first.readonly?
+  end
+
+  test "eager-loading readonly association" do
+    skip "eager_load does not yet preserve readonly associations"
+    # has-one
+    firm = Firm.where(id: "1").eager_load(:readonly_account).first!
+    assert firm.readonly_account.readonly?
+
+    # has_and_belongs_to_many
+    project = Project.where(id: "2").eager_load(:readonly_developers).first!
+    assert project.readonly_developers.first.readonly?
+
+    # has-many :through
+    david = Author.where(id: "1").eager_load(:readonly_comments).first!
+    assert david.readonly_comments.first.readonly?
+  end
+end
diff --git a/activerecord/test/cases/associations/extension_test.rb b/activerecord/test/cases/associations/extension_test.rb
new file mode 100644
index 0000000000..4c1fdfdd9a
--- /dev/null
+++ b/activerecord/test/cases/associations/extension_test.rb
@@ -0,0 +1,81 @@
+require "cases/helper"
+require 'models/post'
+require 'models/comment'
+require 'models/project'
+require 'models/developer'
+require 'models/company_in_module'
+
+class AssociationsExtensionsTest < ActiveRecord::TestCase
+  fixtures :projects, :developers, :developers_projects, :comments, :posts
+
+  def test_extension_on_has_many
+    assert_equal comments(:more_greetings), posts(:welcome).comments.find_most_recent
+  end
+
+  def test_extension_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects.find_most_recent
+  end
+
+  def test_named_extension_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name.find_most_recent
+  end
+
+  def test_named_two_extensions_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name_twice.find_most_recent
+    assert_equal projects(:active_record), developers(:david).projects_extended_by_name_twice.find_least_recent
+  end
+
+  def test_named_extension_and_block_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name_and_block.find_most_recent
+    assert_equal projects(:active_record), developers(:david).projects_extended_by_name_and_block.find_least_recent
+  end
+
+  def test_extension_with_scopes
+    assert_equal comments(:greetings), posts(:welcome).comments.offset(1).find_most_recent
+    assert_equal comments(:greetings), posts(:welcome).comments.not_again.find_most_recent
+  end
+
+  def test_marshalling_extensions
+    david = developers(:david)
+    assert_equal projects(:action_controller), david.projects.find_most_recent
+
+    marshalled = Marshal.dump(david)
+
+    # Marshaling an association shouldn't make it unusable by wiping its reflection.
+    assert_not_nil david.association(:projects).reflection
+
+    david_too  = Marshal.load(marshalled)
+    assert_equal projects(:action_controller), david_too.projects.find_most_recent
+  end
+
+  def test_marshalling_named_extensions
+    david = developers(:david)
+    assert_equal projects(:action_controller), david.projects_extended_by_name.find_most_recent
+
+    marshalled = Marshal.dump(david)
+    david      = Marshal.load(marshalled)
+
+    assert_equal projects(:action_controller), david.projects_extended_by_name.find_most_recent
+  end
+
+  def test_extension_name
+    extend!(Developer)
+    extend!(MyApplication::Business::Developer)
+
+    assert Object.const_get 'DeveloperAssociationNameAssociationExtension'
+    assert MyApplication::Business.const_get 'DeveloperAssociationNameAssociationExtension'
+  end
+
+  def test_proxy_association_after_scoped
+    post = posts(:welcome)
+    assert_equal post.association(:comments), post.comments.the_association
+    assert_equal post.association(:comments), post.comments.where('1=1').the_association
+  end
+
+  private
+
+    def extend!(model)
+      builder = ActiveRecord::Associations::Builder::HasMany.new(model, :association_name, nil, {}) { }
+      builder.define_extensions(model)
+    end
+end
diff --git a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
new file mode 100644
index 0000000000..cc58a4a1a2
--- /dev/null
+++ b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
@@ -0,0 +1,886 @@
+require "cases/helper"
+require 'models/developer'
+require 'models/project'
+require 'models/company'
+require 'models/customer'
+require 'models/order'
+require 'models/categorization'
+require 'models/category'
+require 'models/post'
+require 'models/author'
+require 'models/tag'
+require 'models/tagging'
+require 'models/parrot'
+require 'models/person'
+require 'models/pirate'
+require 'models/treasure'
+require 'models/price_estimate'
+require 'models/club'
+require 'models/member'
+require 'models/membership'
+require 'models/sponsor'
+require 'models/country'
+require 'models/treaty'
+require 'models/vertex'
+require 'models/publisher'
+require 'models/publisher/article'
+require 'models/publisher/magazine'
+require 'active_support/core_ext/string/conversions'
+
+class ProjectWithAfterCreateHook < ActiveRecord::Base
+  self.table_name = 'projects'
+  has_and_belongs_to_many :developers,
+    :class_name => "DeveloperForProjectWithAfterCreateHook",
+    :join_table => "developers_projects",
+    :foreign_key => "project_id",
+    :association_foreign_key => "developer_id"
+
+  after_create :add_david
+
+  def add_david
+    david = DeveloperForProjectWithAfterCreateHook.find_by_name('David')
+    david.projects << self
+  end
+end
+
+class DeveloperForProjectWithAfterCreateHook < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects,
+    :class_name => "ProjectWithAfterCreateHook",
+    :join_table => "developers_projects",
+    :association_foreign_key => "project_id",
+    :foreign_key => "developer_id"
+end
+
+class ProjectWithSymbolsForKeys < ActiveRecord::Base
+  self.table_name = 'projects'
+  has_and_belongs_to_many :developers,
+    :class_name => "DeveloperWithSymbolsForKeys",
+    :join_table => :developers_projects,
+    :foreign_key => :project_id,
+    :association_foreign_key => "developer_id"
+end
+
+class DeveloperWithSymbolsForKeys < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects,
+    :class_name => "ProjectWithSymbolsForKeys",
+    :join_table => :developers_projects,
+    :association_foreign_key => :project_id,
+    :foreign_key => "developer_id"
+end
+
+class SubDeveloper < Developer
+  self.table_name = 'developers'
+  has_and_belongs_to_many :special_projects,
+    :join_table => 'developers_projects',
+    :foreign_key => "project_id",
+    :association_foreign_key => "developer_id"
+end
+
+class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :categories, :posts, :categories_posts, :developers, :projects, :developers_projects,
+           :parrots, :pirates, :parrots_pirates, :treasures, :price_estimates, :tags, :taggings
+
+  def setup_data_for_habtm_case
+    ActiveRecord::Base.connection.execute('delete from countries_treaties')
+
+    country = Country.new(:name => 'India')
+    country.country_id = 'c1'
+    country.save!
+
+    treaty = Treaty.new(:name => 'peace')
+    treaty.treaty_id = 't1'
+    country.treaties << treaty
+  end
+
+  def test_marshal_dump
+    post = posts :welcome
+    preloaded = Post.includes(:categories).find post.id
+    assert_equal preloaded, Marshal.load(Marshal.dump(preloaded))
+  end
+
+  def test_should_property_quote_string_primary_keys
+    setup_data_for_habtm_case
+
+    con = ActiveRecord::Base.connection
+    sql = 'select * from countries_treaties'
+    record = con.select_rows(sql).last
+    assert_equal 'c1', record[0]
+    assert_equal 't1', record[1]
+  end
+
+  def test_proper_usage_of_primary_keys_and_join_table
+    setup_data_for_habtm_case
+
+    assert_equal 'country_id', Country.primary_key
+    assert_equal 'treaty_id', Treaty.primary_key
+
+    country = Country.first
+    assert_equal 1, country.treaties.count
+  end
+
+  def test_has_and_belongs_to_many
+    david = Developer.find(1)
+
+    assert !david.projects.empty?
+    assert_equal 2, david.projects.size
+
+    active_record = Project.find(1)
+    assert !active_record.developers.empty?
+    assert_equal 3, active_record.developers.size
+    assert active_record.developers.include?(david)
+  end
+
+  def test_adding_single
+    jamis = Developer.find(2)
+    jamis.projects.reload # causing the collection to load
+    action_controller = Project.find(2)
+    assert_equal 1, jamis.projects.size
+    assert_equal 1, action_controller.developers.size
+
+    jamis.projects << action_controller
+
+    assert_equal 2, jamis.projects.size
+    assert_equal 2, jamis.projects(true).size
+    assert_equal 2, action_controller.developers(true).size
+  end
+
+  def test_adding_type_mismatch
+    jamis = Developer.find(2)
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { jamis.projects << nil }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { jamis.projects << 1 }
+  end
+
+  def test_adding_from_the_project
+    jamis = Developer.find(2)
+    action_controller = Project.find(2)
+    action_controller.developers.reload
+    assert_equal 1, jamis.projects.size
+    assert_equal 1, action_controller.developers.size
+
+    action_controller.developers << jamis
+
+    assert_equal 2, jamis.projects(true).size
+    assert_equal 2, action_controller.developers.size
+    assert_equal 2, action_controller.developers(true).size
+  end
+
+  def test_adding_from_the_project_fixed_timestamp
+    jamis = Developer.find(2)
+    action_controller = Project.find(2)
+    action_controller.developers.reload
+    assert_equal 1, jamis.projects.size
+    assert_equal 1, action_controller.developers.size
+    updated_at = jamis.updated_at
+
+    action_controller.developers << jamis
+
+    assert_equal updated_at, jamis.updated_at
+    assert_equal 2, jamis.projects(true).size
+    assert_equal 2, action_controller.developers.size
+    assert_equal 2, action_controller.developers(true).size
+  end
+
+  def test_adding_multiple
+    aredridel = Developer.new("name" => "Aredridel")
+    aredridel.save
+    aredridel.projects.reload
+    aredridel.projects.push(Project.find(1), Project.find(2))
+    assert_equal 2, aredridel.projects.size
+    assert_equal 2, aredridel.projects(true).size
+  end
+
+  def test_adding_a_collection
+    aredridel = Developer.new("name" => "Aredridel")
+    aredridel.save
+    aredridel.projects.reload
+    aredridel.projects.concat([Project.find(1), Project.find(2)])
+    assert_equal 2, aredridel.projects.size
+    assert_equal 2, aredridel.projects(true).size
+  end
+
+  def test_habtm_adding_before_save
+    no_of_devels = Developer.count
+    no_of_projects = Project.count
+    aredridel = Developer.new("name" => "Aredridel")
+    aredridel.projects.concat([Project.find(1), p = Project.new("name" => "Projekt")])
+    assert !aredridel.persisted?
+    assert !p.persisted?
+    assert aredridel.save
+    assert aredridel.persisted?
+    assert_equal no_of_devels+1, Developer.count
+    assert_equal no_of_projects+1, Project.count
+    assert_equal 2, aredridel.projects.size
+    assert_equal 2, aredridel.projects(true).size
+  end
+
+  def test_habtm_saving_multiple_relationships
+    new_project = Project.new("name" => "Grimetime")
+    amount_of_developers = 4
+    developers = (0...amount_of_developers).collect {|i| Developer.create(:name => "JME #{i}") }.reverse
+
+    new_project.developer_ids = [developers[0].id, developers[1].id]
+    new_project.developers_with_callback_ids = [developers[2].id, developers[3].id]
+    assert new_project.save
+
+    new_project.reload
+    assert_equal amount_of_developers, new_project.developers.size
+    assert_equal developers, new_project.developers
+  end
+
+  def test_habtm_unique_order_preserved
+    assert_equal developers(:poor_jamis, :jamis, :david), projects(:active_record).non_unique_developers
+    assert_equal developers(:poor_jamis, :jamis, :david), projects(:active_record).developers
+  end
+
+  def test_habtm_collection_size_from_build
+    devel = Developer.create("name" => "Fred Wu")
+    devel.projects << Project.create("name" => "Grimetime")
+    devel.projects.build
+
+    assert_equal 2, devel.projects.size
+  end
+
+  def test_habtm_collection_size_from_params
+    devel = Developer.new({
+      projects_attributes: {
+        '0' => {}
+      }
+    })
+
+    assert_equal 1, devel.projects.size
+  end
+
+  def test_build
+    devel = Developer.find(1)
+    proj = assert_no_queries { devel.projects.build("name" => "Projekt") }
+    assert !devel.projects.loaded?
+
+    assert_equal devel.projects.last, proj
+    assert devel.projects.loaded?
+
+    assert !proj.persisted?
+    devel.save
+    assert proj.persisted?
+    assert_equal devel.projects.last, proj
+    assert_equal Developer.find(1).projects.sort_by(&:id).last, proj  # prove join table is updated
+  end
+
+  def test_new_aliased_to_build
+    devel = Developer.find(1)
+    proj = assert_no_queries { devel.projects.new("name" => "Projekt") }
+    assert !devel.projects.loaded?
+
+    assert_equal devel.projects.last, proj
+    assert devel.projects.loaded?
+
+    assert !proj.persisted?
+    devel.save
+    assert proj.persisted?
+    assert_equal devel.projects.last, proj
+    assert_equal Developer.find(1).projects.sort_by(&:id).last, proj  # prove join table is updated
+  end
+
+  def test_build_by_new_record
+    devel = Developer.new(:name => "Marcel", :salary => 75000)
+    devel.projects.build(:name => "Make bed")
+    proj2 = devel.projects.build(:name => "Lie in it")
+    assert_equal devel.projects.last, proj2
+    assert !proj2.persisted?
+    devel.save
+    assert devel.persisted?
+    assert proj2.persisted?
+    assert_equal devel.projects.last, proj2
+    assert_equal Developer.find_by_name("Marcel").projects.last, proj2  # prove join table is updated
+  end
+
+  def test_create
+    devel = Developer.find(1)
+    proj = devel.projects.create("name" => "Projekt")
+    assert !devel.projects.loaded?
+
+    assert_equal devel.projects.last, proj
+    assert !devel.projects.loaded?
+
+    assert proj.persisted?
+    assert_equal Developer.find(1).projects.sort_by(&:id).last, proj  # prove join table is updated
+  end
+
+  def test_create_by_new_record
+    devel = Developer.new(:name => "Marcel", :salary => 75000)
+    devel.projects.build(:name => "Make bed")
+    proj2 = devel.projects.build(:name => "Lie in it")
+    assert_equal devel.projects.last, proj2
+    assert !proj2.persisted?
+    devel.save
+    assert devel.persisted?
+    assert proj2.persisted?
+    assert_equal devel.projects.last, proj2
+    assert_equal Developer.find_by_name("Marcel").projects.last, proj2  # prove join table is updated
+  end
+
+  def test_creation_respects_hash_condition
+    # in Oracle '' is saved as null therefore need to save ' ' in not null column
+    post = categories(:general).post_with_conditions.build(:body => ' ')
+
+    assert        post.save
+    assert_equal  'Yet Another Testing Title', post.title
+
+    # in Oracle '' is saved as null therefore need to save ' ' in not null column
+    another_post = categories(:general).post_with_conditions.create(:body => ' ')
+
+    assert        another_post.persisted?
+    assert_equal  'Yet Another Testing Title', another_post.title
+  end
+
+  def test_uniq_after_the_fact
+    dev = developers(:jamis)
+    dev.projects << projects(:active_record)
+    dev.projects << projects(:active_record)
+
+    assert_equal 3, dev.projects.size
+    assert_equal 1, dev.projects.distinct.size
+  end
+
+  def test_uniq_before_the_fact
+    projects(:active_record).developers << developers(:jamis)
+    projects(:active_record).developers << developers(:david)
+    assert_equal 3, projects(:active_record, :reload).developers.size
+  end
+
+  def test_uniq_option_prevents_duplicate_push
+    project = projects(:active_record)
+    project.developers << developers(:jamis)
+    project.developers << developers(:david)
+    assert_equal 3, project.developers.size
+
+    project.developers << developers(:david)
+    project.developers << developers(:jamis)
+    assert_equal 3, project.developers.size
+  end
+
+  def test_uniq_when_association_already_loaded
+    project = projects(:active_record)
+    project.developers << [ developers(:jamis), developers(:david), developers(:jamis), developers(:david) ]
+    assert_equal 3, Project.includes(:developers).find(project.id).developers.size
+  end
+
+  def test_deleting
+    david = Developer.find(1)
+    active_record = Project.find(1)
+    david.projects.reload
+    assert_equal 2, david.projects.size
+    assert_equal 3, active_record.developers.size
+
+    david.projects.delete(active_record)
+
+    assert_equal 1, david.projects.size
+    assert_equal 1, david.projects(true).size
+    assert_equal 2, active_record.developers(true).size
+  end
+
+  def test_deleting_array
+    david = Developer.find(1)
+    david.projects.reload
+    david.projects.delete(Project.all.to_a)
+    assert_equal 0, david.projects.size
+    assert_equal 0, david.projects(true).size
+  end
+
+  def test_deleting_all
+    david = Developer.find(1)
+    david.projects.reload
+    david.projects.clear
+    assert_equal 0, david.projects.size
+    assert_equal 0, david.projects(true).size
+  end
+
+  def test_removing_associations_on_destroy
+    david = DeveloperWithBeforeDestroyRaise.find(1)
+    assert !david.projects.empty?
+    david.destroy
+    assert david.projects.empty?
+    assert DeveloperWithBeforeDestroyRaise.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = 1").empty?
+  end
+
+  def test_destroying
+    david = Developer.find(1)
+    project = Project.find(1)
+    david.projects.reload
+    assert_equal 2, david.projects.size
+    assert_equal 3, project.developers.size
+
+    assert_no_difference "Project.count" do
+      david.projects.destroy(project)
+    end
+
+    join_records = Developer.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = #{david.id} AND project_id = #{project.id}")
+    assert join_records.empty?
+
+    assert_equal 1, david.reload.projects.size
+    assert_equal 1, david.projects(true).size
+  end
+
+  def test_destroying_many
+    david = Developer.find(1)
+    david.projects.reload
+    projects = Project.all.to_a
+
+    assert_no_difference "Project.count" do
+      david.projects.destroy(*projects)
+    end
+
+    join_records = Developer.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = #{david.id}")
+    assert join_records.empty?
+
+    assert_equal 0, david.reload.projects.size
+    assert_equal 0, david.projects(true).size
+  end
+
+  def test_destroy_all
+    david = Developer.find(1)
+    david.projects.reload
+    assert !david.projects.empty?
+
+    assert_no_difference "Project.count" do
+      david.projects.destroy_all
+    end
+
+    join_records = Developer.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = #{david.id}")
+    assert join_records.empty?
+
+    assert david.projects.empty?
+    assert david.projects(true).empty?
+  end
+
+  def test_destroy_associations_destroys_multiple_associations
+    george = parrots(:george)
+    assert !george.pirates.empty?
+    assert !george.treasures.empty?
+
+    assert_no_difference "Pirate.count" do
+      assert_no_difference "Treasure.count" do
+        george.destroy_associations
+      end
+    end
+
+    join_records = Parrot.connection.select_all("SELECT * FROM parrots_pirates WHERE parrot_id = #{george.id}")
+    assert join_records.empty?
+    assert george.pirates(true).empty?
+
+    join_records = Parrot.connection.select_all("SELECT * FROM parrots_treasures WHERE parrot_id = #{george.id}")
+    assert join_records.empty?
+    assert george.treasures(true).empty?
+  end
+
+  def test_associations_with_conditions
+    assert_equal 3, projects(:active_record).developers.size
+    assert_equal 1, projects(:active_record).developers_named_david.size
+    assert_equal 1, projects(:active_record).developers_named_david_with_hash_conditions.size
+
+    assert_equal developers(:david), projects(:active_record).developers_named_david.find(developers(:david).id)
+    assert_equal developers(:david), projects(:active_record).developers_named_david_with_hash_conditions.find(developers(:david).id)
+    assert_equal developers(:david), projects(:active_record).salaried_developers.find(developers(:david).id)
+
+    projects(:active_record).developers_named_david.clear
+    assert_equal 2, projects(:active_record, :reload).developers.size
+  end
+
+  def test_find_in_association
+    # Using sql
+    assert_equal developers(:david), projects(:active_record).developers.find(developers(:david).id), "SQL find"
+
+    # Using ruby
+    active_record = projects(:active_record)
+    active_record.developers.reload
+    assert_equal developers(:david), active_record.developers.find(developers(:david).id), "Ruby find"
+  end
+
+  def test_include_uses_array_include_after_loaded
+    project = projects(:active_record)
+    project.developers.load_target
+
+    developer = project.developers.first
+
+    assert_no_queries do
+      assert project.developers.loaded?
+      assert project.developers.include?(developer)
+    end
+  end
+
+  def test_include_checks_if_record_exists_if_target_not_loaded
+    project = projects(:active_record)
+    developer = project.developers.first
+
+    project.reload
+    assert ! project.developers.loaded?
+    assert_queries(1) do
+      assert project.developers.include?(developer)
+    end
+    assert ! project.developers.loaded?
+  end
+
+  def test_include_returns_false_for_non_matching_record_to_verify_scoping
+    project = projects(:active_record)
+    developer = Developer.create :name => "Bryan", :salary => 50_000
+
+    assert ! project.developers.loaded?
+    assert ! project.developers.include?(developer)
+  end
+
+  def test_find_with_merged_options
+    assert_equal 1, projects(:active_record).limited_developers.size
+    assert_equal 1, projects(:active_record).limited_developers.to_a.size
+    assert_equal 3, projects(:active_record).limited_developers.limit(nil).to_a.size
+  end
+
+  def test_dynamic_find_should_respect_association_order
+    # Developers are ordered 'name DESC, id DESC'
+    high_id_jamis = projects(:active_record).developers.create(:name => 'Jamis')
+
+    assert_equal high_id_jamis, projects(:active_record).developers.merge(:where => "name = 'Jamis'").first
+    assert_equal high_id_jamis, projects(:active_record).developers.find_by_name('Jamis')
+  end
+
+  def test_find_should_append_to_association_order
+    ordered_developers = projects(:active_record).developers.order('projects.id')
+    assert_equal ['developers.name desc, developers.id desc', 'projects.id'], ordered_developers.order_values
+  end
+
+  def test_dynamic_find_all_should_respect_readonly_access
+    projects(:active_record).readonly_developers.each { |d| assert_raise(ActiveRecord::ReadOnlyRecord) { d.save!  } if d.valid?}
+    projects(:active_record).readonly_developers.each { |d| d.readonly? }
+  end
+
+  def test_new_with_values_in_collection
+    jamis = DeveloperForProjectWithAfterCreateHook.find_by_name('Jamis')
+    david = DeveloperForProjectWithAfterCreateHook.find_by_name('David')
+    project = ProjectWithAfterCreateHook.new(:name => "Cooking with Bertie")
+    project.developers << jamis
+    project.save!
+    project.reload
+
+    assert project.developers.include?(jamis)
+    assert project.developers.include?(david)
+  end
+
+  def test_find_in_association_with_options
+    developers = projects(:active_record).developers.to_a
+    assert_equal 3, developers.size
+
+    assert_equal developers(:poor_jamis), projects(:active_record).developers.where("salary < 10000").first
+  end
+
+  def test_replace_with_less
+    david = developers(:david)
+    david.projects = [projects(:action_controller)]
+    assert david.save
+    assert_equal 1, david.projects.length
+  end
+
+  def test_replace_with_new
+    david = developers(:david)
+    david.projects = [projects(:action_controller), Project.new("name" => "ActionWebSearch")]
+    david.save
+    assert_equal 2, david.projects.length
+    assert !david.projects.include?(projects(:active_record))
+  end
+
+  def test_replace_on_new_object
+    new_developer = Developer.new("name" => "Matz")
+    new_developer.projects = [projects(:action_controller), Project.new("name" => "ActionWebSearch")]
+    new_developer.save
+    assert_equal 2, new_developer.projects.length
+  end
+
+  def test_consider_type
+    developer = Developer.first
+    special_project = SpecialProject.create("name" => "Special Project")
+
+    other_project = developer.projects.first
+    developer.special_projects << special_project
+    developer.reload
+
+    assert developer.projects.include?(special_project)
+    assert developer.special_projects.include?(special_project)
+    assert !developer.special_projects.include?(other_project)
+  end
+
+  def test_symbol_join_table
+    developer = Developer.first
+    sp = developer.sym_special_projects.create("name" => "omg")
+    developer.reload
+    assert_includes developer.sym_special_projects, sp
+  end
+
+  def test_update_attributes_after_push_without_duplicate_join_table_rows
+    developer = Developer.new("name" => "Kano")
+    project = SpecialProject.create("name" => "Special Project")
+    assert developer.save
+    developer.projects << project
+    developer.update_columns("name" => "Bruza")
+    assert_equal 1, Developer.connection.select_value(<<-end_sql).to_i
+      SELECT count(*) FROM developers_projects
+      WHERE project_id = #{project.id}
+      AND developer_id = #{developer.id}
+    end_sql
+  end
+
+  def test_updating_attributes_on_non_rich_associations
+    welcome = categories(:technology).posts.first
+    welcome.title = "Something else"
+    assert welcome.save!
+  end
+
+  def test_habtm_respects_select
+    categories(:technology).select_testing_posts(true).each do |o|
+      assert_respond_to o, :correctness_marker
+    end
+    assert_respond_to categories(:technology).select_testing_posts.first, :correctness_marker
+  end
+
+  def test_habtm_selects_all_columns_by_default
+    assert_equal Project.column_names.sort, developers(:david).projects.first.attributes.keys.sort
+  end
+
+  def test_habtm_respects_select_query_method
+    assert_equal ['id'], developers(:david).projects.select(:id).first.attributes.keys
+  end
+
+  def test_join_table_alias
+    # FIXME: `references` has no impact on the aliases generated for the join
+    # query.  The fact that we pass `:developers_projects_join` to `references`
+    # and that the SQL string contains `developers_projects_join` is merely a
+    # coincidence.
+    assert_equal(
+      3,
+      Developer.references(:developers_projects_join).merge(
+        :includes => {:projects => :developers},
+        :where => 'projects_developers_projects_join.joined_on IS NOT NULL'
+      ).to_a.size
+    )
+  end
+
+  def test_join_with_group
+    # FIXME: `references` has no impact on the aliases generated for the join
+    # query.  The fact that we pass `:developers_projects_join` to `references`
+    # and that the SQL string contains `developers_projects_join` is merely a
+    # coincidence.
+    group = Developer.columns.inject([]) do |g, c|
+      g << "developers.#{c.name}"
+      g << "developers_projects_2.#{c.name}"
+    end
+    Project.columns.each { |c| group << "projects.#{c.name}" }
+
+    assert_equal(
+      3,
+      Developer.references(:developers_projects_join).merge(
+        :includes => {:projects => :developers}, :where => 'projects_developers_projects_join.joined_on IS NOT NULL',
+        :group => group.join(",")
+      ).to_a.size
+    )
+  end
+
+  def test_find_grouped
+    all_posts_from_category1 = Post.all.merge!(:where => "category_id = 1", :joins => :categories).to_a
+    grouped_posts_of_category1 = Post.all.merge!(:where => "category_id = 1", :group => "author_id", :select => 'count(posts.id) as posts_count', :joins => :categories).to_a
+    assert_equal 5, all_posts_from_category1.size
+    assert_equal 2, grouped_posts_of_category1.size
+  end
+
+  def test_find_scoped_grouped
+    assert_equal 5, categories(:general).posts_grouped_by_title.to_a.size
+    assert_equal 1, categories(:technology).posts_grouped_by_title.to_a.size
+  end
+
+  def test_find_scoped_grouped_having
+    assert_equal 2, projects(:active_record).well_payed_salary_groups.to_a.size
+    assert projects(:active_record).well_payed_salary_groups.all? { |g| g.salary > 10000 }
+  end
+
+  def test_get_ids
+    assert_equal projects(:active_record, :action_controller).map(&:id).sort, developers(:david).project_ids.sort
+    assert_equal [projects(:active_record).id], developers(:jamis).project_ids
+  end
+
+  def test_get_ids_for_loaded_associations
+    developer = developers(:david)
+    developer.projects(true)
+    assert_queries(0) do
+      developer.project_ids
+      developer.project_ids
+    end
+  end
+
+  def test_get_ids_for_unloaded_associations_does_not_load_them
+    developer = developers(:david)
+    assert !developer.projects.loaded?
+    assert_equal projects(:active_record, :action_controller).map(&:id).sort, developer.project_ids.sort
+    assert !developer.projects.loaded?
+  end
+
+  def test_assign_ids
+    developer = Developer.new("name" => "Joe")
+    developer.project_ids = projects(:active_record, :action_controller).map(&:id)
+    developer.save
+    developer.reload
+    assert_equal 2, developer.projects.length
+    assert_equal [projects(:active_record), projects(:action_controller)].map(&:id).sort, developer.project_ids.sort
+  end
+
+  def test_assign_ids_ignoring_blanks
+    developer = Developer.new("name" => "Joe")
+    developer.project_ids = [projects(:active_record).id, nil, projects(:action_controller).id, '']
+    developer.save
+    developer.reload
+    assert_equal 2, developer.projects.length
+    assert_equal [projects(:active_record), projects(:action_controller)].map(&:id).sort, developer.project_ids.sort
+  end
+
+  def test_scoped_find_on_through_association_doesnt_return_read_only_records
+    tag = Post.find(1).tags.find_by_name("General")
+
+    assert_nothing_raised do
+      tag.save!
+    end
+  end
+
+  def test_has_many_through_polymorphic_has_manys_works
+    assert_equal [10, 20].to_set, pirates(:redbeard).treasure_estimates.map(&:price).to_set
+  end
+
+  def test_symbols_as_keys
+    developer = DeveloperWithSymbolsForKeys.new(:name => 'David')
+    project = ProjectWithSymbolsForKeys.new(:name => 'Rails Testing')
+    project.developers << developer
+    project.save!
+
+    assert_equal 1, project.developers.size
+    assert_equal 1, developer.projects.size
+    assert_equal developer, project.developers.first
+    assert_equal project, developer.projects.first
+  end
+
+  def test_dynamic_find_should_respect_association_include
+    # SQL error in sort clause if :include is not included
+    # due to Unknown column 'authors.id'
+    assert Category.find(1).posts_with_authors_sorted_by_author_id.find_by_title('Welcome to the weblog')
+  end
+
+  def test_count
+    david = Developer.find(1)
+    assert_equal 2, david.projects.count
+  end
+
+  def test_association_proxy_transaction_method_starts_transaction_in_association_class
+    Post.expects(:transaction)
+    Category.first.posts.transaction do
+      # nothing
+    end
+  end
+
+  def test_caching_of_columns
+    david = Developer.find(1)
+    # clear cache possibly created by other tests
+    david.projects.reset_column_information
+
+    assert_queries(:any) { david.projects.columns }
+    assert_no_queries { david.projects.columns }
+
+    ## and again to verify that reset_column_information clears the cache correctly
+    david.projects.reset_column_information
+
+    assert_queries(:any) { david.projects.columns }
+    assert_no_queries { david.projects.columns }
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_habm_association_with_where_clause
+    new_developer = projects(:action_controller).developers.where(:name => "Marcelo").build
+    assert_equal new_developer.name, "Marcelo"
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_habm_association_with_multiple_where_clauses
+    new_developer = projects(:action_controller).developers.where(:name => "Marcelo").where(:salary => 90_000).build
+    assert_equal new_developer.name, "Marcelo"
+    assert_equal new_developer.salary, 90_000
+  end
+
+  def test_include_method_in_has_and_belongs_to_many_association_should_return_true_for_instance_added_with_build
+    project = Project.new
+    developer = project.developers.build
+    assert project.developers.include?(developer)
+  end
+
+  def test_destruction_does_not_error_without_primary_key
+    redbeard = pirates(:redbeard)
+    george = parrots(:george)
+    redbeard.parrots << george
+    assert_equal 2, george.pirates.count
+    Pirate.includes(:parrots).where(parrot: redbeard.parrot).find(redbeard.id).destroy
+    assert_equal 1, george.pirates.count
+    assert_equal [], Pirate.where(id: redbeard.id)
+  end
+
+  def test_has_and_belongs_to_many_associations_on_new_records_use_null_relations
+    projects = Developer.new.projects
+    assert_no_queries do
+      assert_equal [], projects
+      assert_equal [], projects.where(title: 'omg')
+      assert_equal [], projects.pluck(:title)
+      assert_equal 0, projects.count
+    end
+  end
+
+  def test_association_with_validate_false_does_not_run_associated_validation_callbacks_on_create
+    rich_person = RichPerson.new
+
+    treasure = Treasure.new
+    treasure.rich_people << rich_person
+    treasure.valid?
+
+    assert_equal 1, treasure.rich_people.size
+    assert_nil rich_person.first_name, 'should not run associated person validation on create when validate: false'
+  end
+
+  def test_association_with_validate_false_does_not_run_associated_validation_callbacks_on_update
+    rich_person = RichPerson.create!
+    person_first_name = rich_person.first_name
+    assert_not_nil person_first_name
+
+    treasure = Treasure.new
+    treasure.rich_people << rich_person
+    treasure.valid?
+
+    assert_equal 1, treasure.rich_people.size
+    assert_equal person_first_name, rich_person.first_name, 'should not run associated person validation on update when validate: false'
+  end
+
+  def test_custom_join_table
+    assert_equal 'edges', Vertex.reflect_on_association(:sources).join_table
+  end
+
+  def test_has_and_belongs_to_many_in_a_namespaced_model_pointing_to_a_namespaced_model
+    magazine = Publisher::Magazine.create
+    article = Publisher::Article.create
+    magazine.articles << article
+    magazine.save
+
+    assert_includes magazine.articles, article
+  end
+
+  def test_has_and_belongs_to_many_in_a_namespaced_model_pointing_to_a_non_namespaced_model
+    article = Publisher::Article.create
+    tag = Tag.create
+    article.tags << tag
+    article.save
+
+    assert_includes article.tags, tag
+  end
+
+  def test_redefine_habtm
+    child = SubDeveloper.new("name" => "Aredridel")
+    child.special_projects << SpecialProject.new("name" => "Special Project")
+    assert child.save, 'child object should be saved'
+  end
+end
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
new file mode 100644
index 0000000000..fe961e871c
--- /dev/null
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -0,0 +1,1944 @@
+require "cases/helper"
+require 'models/developer'
+require 'models/project'
+require 'models/company'
+require 'models/contract'
+require 'models/topic'
+require 'models/reply'
+require 'models/category'
+require 'models/post'
+require 'models/author'
+require 'models/essay'
+require 'models/comment'
+require 'models/person'
+require 'models/reader'
+require 'models/tagging'
+require 'models/tag'
+require 'models/invoice'
+require 'models/line_item'
+require 'models/car'
+require 'models/bulb'
+require 'models/engine'
+require 'models/categorization'
+require 'models/minivan'
+require 'models/speedometer'
+require 'models/reference'
+require 'models/job'
+require 'models/college'
+require 'models/student'
+require 'models/pirate'
+require 'models/ship'
+
+class HasManyAssociationsTestForReorderWithJoinDependency < ActiveRecord::TestCase
+  fixtures :authors, :posts, :comments
+
+  def test_should_generate_valid_sql
+    author = authors(:david)
+    # this can fail on adapters which require ORDER BY expressions to be included in the SELECT expression
+    # if the reorder clauses are not correctly handled
+    assert author.posts_with_comments_sorted_by_comment_id.where('comments.id > 0').reorder('posts.comments_count DESC', 'posts.tags_count DESC').last
+  end
+end
+
+
+class HasManyAssociationsTest < ActiveRecord::TestCase
+  fixtures :accounts, :categories, :companies, :developers, :projects,
+           :developers_projects, :topics, :authors, :comments,
+           :people, :posts, :readers, :taggings, :cars, :essays,
+           :categorizations, :jobs, :tags
+
+  def setup
+    Client.destroyed_client_ids.clear
+  end
+
+  def test_sti_subselect_count
+    tag = Tag.first
+    len = Post.tagged_with(tag.id).limit(10).size
+    assert_operator len, :>, 0
+  end
+
+  def test_anonymous_has_many
+    developer = Class.new(ActiveRecord::Base) {
+      self.table_name = 'developers'
+      dev = self
+
+      developer_project = Class.new(ActiveRecord::Base) {
+        self.table_name = 'developers_projects'
+        belongs_to :developer, :class => dev
+      }
+      has_many :developer_projects, :class => developer_project, :foreign_key => 'developer_id'
+    }
+    dev = developer.first
+    named = Developer.find(dev.id)
+    assert_operator dev.developer_projects.count, :>, 0
+    assert_equal named.projects.map(&:id).sort,
+                 dev.developer_projects.map(&:project_id).sort
+  end
+
+  def test_has_many_build_with_options
+    college = College.create(name: 'UFMT')
+    Student.create(active: true, college_id: college.id, name: 'Sarah')
+
+    assert_equal college.students, Student.where(active: true, college_id: college.id)
+  end
+
+  def test_create_from_association_should_respect_default_scope
+    car = Car.create(:name => 'honda')
+    assert_equal 'honda', car.name
+
+    bulb = Bulb.create
+    assert_equal 'defaulty', bulb.name
+
+    bulb = car.bulbs.build
+    assert_equal 'defaulty', bulb.name
+
+    bulb = car.bulbs.create
+    assert_equal 'defaulty', bulb.name
+
+    bulb = car.bulbs.create(:name => 'exotic')
+    assert_equal 'exotic', bulb.name
+  end
+
+  def test_build_from_association_should_respect_scope
+    author = Author.new
+
+    post = author.thinking_posts.build
+    assert_equal 'So I was thinking', post.title
+  end
+
+  def test_create_from_association_with_nil_values_should_work
+    car = Car.create(:name => 'honda')
+
+    bulb = car.bulbs.new(nil)
+    assert_equal 'defaulty', bulb.name
+
+    bulb = car.bulbs.build(nil)
+    assert_equal 'defaulty', bulb.name
+
+    bulb = car.bulbs.create(nil)
+    assert_equal 'defaulty', bulb.name
+  end
+
+  def test_do_not_call_callbacks_for_delete_all
+    car = Car.create(:name => 'honda')
+    car.funky_bulbs.create!
+    assert_nothing_raised { car.reload.funky_bulbs.delete_all }
+    assert_equal 0, Bulb.count, "bulbs should have been deleted using :delete_all strategy"
+  end
+
+  def test_delete_all_on_association_is_the_same_as_not_loaded
+    author = authors :david
+    author.thinking_posts.create!(:body => "test")
+    author.reload
+    expected_sql = capture_sql { author.thinking_posts.delete_all }
+
+    author.thinking_posts.create!(:body => "test")
+    author.reload
+    author.thinking_posts.inspect
+    loaded_sql = capture_sql { author.thinking_posts.delete_all }
+    assert_equal(expected_sql, loaded_sql)
+  end
+
+  def test_delete_all_on_association_with_nil_dependency_is_the_same_as_not_loaded
+    author = authors :david
+    author.posts.create!(:title => "test", :body => "body")
+    author.reload
+    expected_sql = capture_sql { author.posts.delete_all }
+
+    author.posts.create!(:title => "test", :body => "body")
+    author.reload
+    author.posts.to_a
+    loaded_sql = capture_sql { author.posts.delete_all }
+    assert_equal(expected_sql, loaded_sql)
+  end
+
+  def test_building_the_associated_object_with_implicit_sti_base_class
+    firm = DependentFirm.new
+    company = firm.companies.build
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_associated_object_with_explicit_sti_base_class
+    firm = DependentFirm.new
+    company = firm.companies.build(:type => "Company")
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_associated_object_with_sti_subclass
+    firm = DependentFirm.new
+    company = firm.companies.build(:type => "Client")
+    assert_kind_of Client, company, "Expected #{company.class} to be a Client"
+  end
+
+  def test_building_the_associated_object_with_an_invalid_type
+    firm = DependentFirm.new
+    assert_raise(ActiveRecord::SubclassNotFound) { firm.companies.build(:type => "Invalid") }
+  end
+
+  def test_building_the_associated_object_with_an_unrelated_type
+    firm = DependentFirm.new
+    assert_raise(ActiveRecord::SubclassNotFound) { firm.companies.build(:type => "Account") }
+  end
+
+  test "building the association with an array" do
+    speedometer = Speedometer.new(speedometer_id: "a")
+    data = [{name: "first"}, {name: "second"}]
+    speedometer.minivans.build(data)
+
+    assert_equal 2, speedometer.minivans.size
+    assert speedometer.save
+    assert_equal ["first", "second"], speedometer.reload.minivans.map(&:name)
+  end
+
+  def test_association_keys_bypass_attribute_protection
+    car = Car.create(:name => 'honda')
+
+    bulb = car.bulbs.new
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.new :car_id => car.id + 1
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.build
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.build :car_id => car.id + 1
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.create
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.bulbs.create :car_id => car.id + 1
+    assert_equal car.id, bulb.car_id
+  end
+
+  def test_association_protect_foreign_key
+    invoice = Invoice.create
+
+    line_item = invoice.line_items.new
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.new :invoice_id => invoice.id + 1
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.build
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.build :invoice_id => invoice.id + 1
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.create
+    assert_equal invoice.id, line_item.invoice_id
+
+    line_item = invoice.line_items.create :invoice_id => invoice.id + 1
+    assert_equal invoice.id, line_item.invoice_id
+  end
+
+  # When creating objects on the association, we must not do it within a scope (even though it
+  # would be convenient), because this would cause that scope to be applied to any callbacks etc.
+  def test_build_and_create_should_not_happen_within_scope
+    car = cars(:honda)
+    scoped_count = car.foo_bulbs.where_values.count
+
+    bulb = car.foo_bulbs.build
+    assert_not_equal scoped_count, bulb.scope_after_initialize.where_values.count
+
+    bulb = car.foo_bulbs.create
+    assert_not_equal scoped_count, bulb.scope_after_initialize.where_values.count
+
+    bulb = car.foo_bulbs.create!
+    assert_not_equal scoped_count, bulb.scope_after_initialize.where_values.count
+  end
+
+  def test_no_sql_should_be_fired_if_association_already_loaded
+    Car.create(:name => 'honda')
+    bulbs = Car.first.bulbs
+    bulbs.to_a # to load all instances of bulbs
+
+    assert_no_queries do
+      bulbs.first()
+      bulbs.first({})
+    end
+
+    assert_no_queries do
+      bulbs.second()
+      bulbs.second({})
+    end
+
+    assert_no_queries do
+      bulbs.third()
+      bulbs.third({})
+    end
+
+    assert_no_queries do
+      bulbs.fourth()
+      bulbs.fourth({})
+    end
+
+    assert_no_queries do
+      bulbs.fifth()
+      bulbs.fifth({})
+    end
+
+    assert_no_queries do
+      bulbs.forty_two()
+      bulbs.forty_two({})
+    end
+
+    assert_no_queries do
+      bulbs.last()
+      bulbs.last({})
+    end
+  end
+
+  def test_create_resets_cached_counters
+    person = Person.create!(:first_name => 'tenderlove')
+    post   = Post.first
+
+    assert_equal [], person.readers
+    assert_nil person.readers.find_by_post_id(post.id)
+
+    person.readers.create(:post_id => post.id)
+
+    assert_equal 1, person.readers.count
+    assert_equal 1, person.readers.length
+    assert_equal post, person.readers.first.post
+    assert_equal person, person.readers.first.person
+  end
+
+  def force_signal37_to_load_all_clients_of_firm
+    companies(:first_firm).clients_of_firm.each {|f| }
+  end
+
+  # sometimes tests on Oracle fail if ORDER BY is not provided therefore add always :order with :first
+  def test_counting_with_counter_sql
+    assert_equal 3, Firm.all.merge!(:order => "id").first.clients.count
+  end
+
+  def test_counting
+    assert_equal 3, Firm.all.merge!(:order => "id").first.plain_clients.count
+  end
+
+  def test_counting_with_single_hash
+    assert_equal 1, Firm.all.merge!(:order => "id").first.plain_clients.where(:name => "Microsoft").count
+  end
+
+  def test_counting_with_column_name_and_hash
+    assert_equal 3, Firm.all.merge!(:order => "id").first.plain_clients.count(:name)
+  end
+
+  def test_counting_with_association_limit
+    firm = companies(:first_firm)
+    assert_equal firm.limited_clients.length, firm.limited_clients.size
+    assert_equal firm.limited_clients.length, firm.limited_clients.count
+  end
+
+  def test_finding
+    assert_equal 3, Firm.all.merge!(:order => "id").first.clients.length
+  end
+
+  def test_finding_array_compatibility
+    assert_equal 3, Firm.order(:id).find{|f| f.id > 0}.clients.length
+  end
+
+  def test_find_many_with_merged_options
+    assert_equal 1, companies(:first_firm).limited_clients.size
+    assert_equal 1, companies(:first_firm).limited_clients.to_a.size
+    assert_equal 3, companies(:first_firm).limited_clients.limit(nil).to_a.size
+  end
+
+  def test_find_should_append_to_association_order
+    ordered_clients =  companies(:first_firm).clients_sorted_desc.order('companies.id')
+    assert_equal ['id DESC', 'companies.id'], ordered_clients.order_values
+  end
+
+  def test_dynamic_find_should_respect_association_order
+    assert_equal companies(:another_first_firm_client), companies(:first_firm).clients_sorted_desc.where("type = 'Client'").first
+    assert_equal companies(:another_first_firm_client), companies(:first_firm).clients_sorted_desc.find_by_type('Client')
+  end
+
+  def test_cant_save_has_many_readonly_association
+    authors(:david).readonly_comments.each { |c| assert_raise(ActiveRecord::ReadOnlyRecord) { c.save! } }
+    authors(:david).readonly_comments.each { |c| assert c.readonly? }
+  end
+
+  def test_finding_default_orders
+    assert_equal "Summit", Firm.all.merge!(:order => "id").first.clients.first.name
+  end
+
+  def test_finding_with_different_class_name_and_order
+    assert_equal "Apex", Firm.all.merge!(:order => "id").first.clients_sorted_desc.first.name
+  end
+
+  def test_finding_with_foreign_key
+    assert_equal "Microsoft", Firm.all.merge!(:order => "id").first.clients_of_firm.first.name
+  end
+
+  def test_finding_with_condition
+    assert_equal "Microsoft", Firm.all.merge!(:order => "id").first.clients_like_ms.first.name
+  end
+
+  def test_finding_with_condition_hash
+    assert_equal "Microsoft", Firm.all.merge!(:order => "id").first.clients_like_ms_with_hash_conditions.first.name
+  end
+
+  def test_finding_using_primary_key
+    assert_equal "Summit", Firm.all.merge!(:order => "id").first.clients_using_primary_key.first.name
+  end
+
+  def test_belongs_to_sanity
+    c = Client.new
+    assert_nil c.firm, "belongs_to failed sanity check on new object"
+  end
+
+  def test_find_ids
+    firm = Firm.all.merge!(:order => "id").first
+
+    assert_raise(ActiveRecord::RecordNotFound) { firm.clients.find }
+
+    client = firm.clients.find(2)
+    assert_kind_of Client, client
+
+    client_ary = firm.clients.find([2])
+    assert_kind_of Array, client_ary
+    assert_equal client, client_ary.first
+
+    client_ary = firm.clients.find(2, 3)
+    assert_kind_of Array, client_ary
+    assert_equal 2, client_ary.size
+    assert_equal client, client_ary.first
+
+    assert_raise(ActiveRecord::RecordNotFound) { firm.clients.find(2, 99) }
+  end
+
+  def test_find_ids_and_inverse_of
+    force_signal37_to_load_all_clients_of_firm
+
+    firm = companies(:first_firm)
+    client = firm.clients_of_firm.find(3)
+    assert_kind_of Client, client
+
+    client_ary = firm.clients_of_firm.find([3])
+    assert_kind_of Array, client_ary
+    assert_equal client, client_ary.first
+  end
+
+  def test_find_all
+    firm = Firm.all.merge!(:order => "id").first
+    assert_equal 3, firm.clients.where("#{QUOTED_TYPE} = 'Client'").to_a.length
+    assert_equal 1, firm.clients.where("name = 'Summit'").to_a.length
+  end
+
+  def test_find_each
+    firm = companies(:first_firm)
+
+    assert ! firm.clients.loaded?
+
+    assert_queries(4) do
+      firm.clients.find_each(:batch_size => 1) {|c| assert_equal firm.id, c.firm_id }
+    end
+
+    assert ! firm.clients.loaded?
+  end
+
+  def test_find_each_with_conditions
+    firm = companies(:first_firm)
+
+    assert_queries(2) do
+      firm.clients.where(name: 'Microsoft').find_each(batch_size: 1) do |c|
+        assert_equal firm.id, c.firm_id
+        assert_equal "Microsoft", c.name
+      end
+    end
+
+    assert ! firm.clients.loaded?
+  end
+
+  def test_find_in_batches
+    firm = companies(:first_firm)
+
+    assert ! firm.clients.loaded?
+
+    assert_queries(2) do
+      firm.clients.find_in_batches(:batch_size => 2) do |clients|
+        clients.each {|c| assert_equal firm.id, c.firm_id }
+      end
+    end
+
+    assert ! firm.clients.loaded?
+  end
+
+  def test_find_all_sanitized
+    # sometimes tests on Oracle fail if ORDER BY is not provided therefore add always :order with :first
+    firm = Firm.all.merge!(:order => "id").first
+    summit = firm.clients.where("name = 'Summit'").to_a
+    assert_equal summit, firm.clients.where("name = ?", "Summit").to_a
+    assert_equal summit, firm.clients.where("name = :name", { :name => "Summit" }).to_a
+  end
+
+  def test_find_first
+    firm = Firm.all.merge!(:order => "id").first
+    client2 = Client.find(2)
+    assert_equal firm.clients.first, firm.clients.order("id").first
+    assert_equal client2, firm.clients.where("#{QUOTED_TYPE} = 'Client'").order("id").first
+  end
+
+  def test_find_first_sanitized
+    firm = Firm.all.merge!(:order => "id").first
+    client2 = Client.find(2)
+    assert_equal client2, firm.clients.merge!(:where => ["#{QUOTED_TYPE} = ?", 'Client'], :order => "id").first
+    assert_equal client2, firm.clients.merge!(:where => ["#{QUOTED_TYPE} = :type", { :type => 'Client' }], :order => "id").first
+  end
+
+  def test_find_all_with_include_and_conditions
+    assert_nothing_raised do
+      Developer.all.merge!(:joins => :audit_logs, :where => {'audit_logs.message' => nil, :name => 'Smith'}).to_a
+    end
+  end
+
+  def test_find_in_collection
+    assert_equal Client.find(2).name, companies(:first_firm).clients.find(2).name
+    assert_raise(ActiveRecord::RecordNotFound) { companies(:first_firm).clients.find(6) }
+  end
+
+  def test_find_grouped
+    all_clients_of_firm1 = Client.all.merge!(:where => "firm_id = 1").to_a
+    grouped_clients_of_firm1 = Client.all.merge!(:where => "firm_id = 1", :group => "firm_id", :select => 'firm_id, count(id) as clients_count').to_a
+    assert_equal 3, all_clients_of_firm1.size
+    assert_equal 1, grouped_clients_of_firm1.size
+  end
+
+  def test_find_scoped_grouped
+    assert_equal 1, companies(:first_firm).clients_grouped_by_firm_id.size
+    assert_equal 1, companies(:first_firm).clients_grouped_by_firm_id.length
+    assert_equal 3, companies(:first_firm).clients_grouped_by_name.size
+    assert_equal 3, companies(:first_firm).clients_grouped_by_name.length
+  end
+
+  def test_find_scoped_grouped_having
+    assert_equal 1, authors(:david).popular_grouped_posts.length
+    assert_equal 0, authors(:mary).popular_grouped_posts.length
+  end
+
+  def test_default_select
+    assert_equal Comment.column_names.sort, posts(:welcome).comments.first.attributes.keys.sort
+  end
+
+  def test_select_query_method
+    assert_equal ['id', 'body'], posts(:welcome).comments.select(:id, :body).first.attributes.keys
+  end
+
+  def test_select_with_block
+    assert_equal [1], posts(:welcome).comments.select { |c| c.id == 1 }.map(&:id)
+  end
+
+  def test_select_without_foreign_key
+    assert_equal companies(:first_firm).accounts.first.credit_limit, companies(:first_firm).accounts.select(:credit_limit).first.credit_limit
+  end
+
+  def test_adding
+    force_signal37_to_load_all_clients_of_firm
+    natural = Client.new("name" => "Natural Company")
+    companies(:first_firm).clients_of_firm << natural
+    assert_equal 3, companies(:first_firm).clients_of_firm.size # checking via the collection
+    assert_equal 3, companies(:first_firm).clients_of_firm(true).size # checking using the db
+    assert_equal natural, companies(:first_firm).clients_of_firm.last
+  end
+
+  def test_adding_using_create
+    first_firm = companies(:first_firm)
+    assert_equal 3, first_firm.plain_clients.size
+    first_firm.plain_clients.create(:name => "Natural Company")
+    assert_equal 4, first_firm.plain_clients.length
+    assert_equal 4, first_firm.plain_clients.size
+  end
+
+  def test_create_with_bang_on_has_many_when_parent_is_new_raises
+    assert_raise(ActiveRecord::RecordNotSaved) do
+      firm = Firm.new
+      firm.plain_clients.create! :name=>"Whoever"
+    end
+  end
+
+  def test_regular_create_on_has_many_when_parent_is_new_raises
+    assert_raise(ActiveRecord::RecordNotSaved) do
+      firm = Firm.new
+      firm.plain_clients.create :name=>"Whoever"
+    end
+  end
+
+  def test_create_with_bang_on_has_many_raises_when_record_not_saved
+    assert_raise(ActiveRecord::RecordInvalid) do
+      firm = Firm.all.merge!(:order => "id").first
+      firm.plain_clients.create!
+    end
+  end
+
+  def test_create_with_bang_on_habtm_when_parent_is_new_raises
+    assert_raise(ActiveRecord::RecordNotSaved) do
+      Developer.new("name" => "Aredridel").projects.create!
+    end
+  end
+
+  def test_adding_a_mismatch_class
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).clients_of_firm << nil }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).clients_of_firm << 1 }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).clients_of_firm << Topic.find(1) }
+  end
+
+  def test_adding_a_collection
+    force_signal37_to_load_all_clients_of_firm
+    companies(:first_firm).clients_of_firm.concat([Client.new("name" => "Natural Company"), Client.new("name" => "Apple")])
+    assert_equal 4, companies(:first_firm).clients_of_firm.size
+    assert_equal 4, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_transactions_when_adding_to_persisted
+    good = Client.new(:name => "Good")
+    bad  = Client.new(:name => "Bad", :raise_on_save => true)
+
+    begin
+      companies(:first_firm).clients_of_firm.concat(good, bad)
+    rescue Client::RaisedOnSave
+    end
+
+    assert !companies(:first_firm).clients_of_firm(true).include?(good)
+  end
+
+  def test_transactions_when_adding_to_new_record
+    assert_no_queries do
+      firm = Firm.new
+      firm.clients_of_firm.concat(Client.new("name" => "Natural Company"))
+    end
+  end
+
+  def test_inverse_on_before_validate
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients_of_firm << Client.new("name" => "Natural Company")
+    end
+  end
+
+  def test_new_aliased_to_build
+    company = companies(:first_firm)
+    new_client = assert_no_queries { company.clients_of_firm.new("name" => "Another Client") }
+    assert !company.clients_of_firm.loaded?
+
+    assert_equal "Another Client", new_client.name
+    assert !new_client.persisted?
+    assert_equal new_client, company.clients_of_firm.last
+  end
+
+  def test_build
+    company = companies(:first_firm)
+    new_client = assert_no_queries { company.clients_of_firm.build("name" => "Another Client") }
+    assert !company.clients_of_firm.loaded?
+
+    assert_equal "Another Client", new_client.name
+    assert !new_client.persisted?
+    assert_equal new_client, company.clients_of_firm.last
+  end
+
+  def test_collection_size_after_building
+    company = companies(:first_firm)  # company already has one client
+    company.clients_of_firm.build("name" => "Another Client")
+    company.clients_of_firm.build("name" => "Yet Another Client")
+    assert_equal 4, company.clients_of_firm.size
+  end
+
+  def test_collection_not_empty_after_building
+    company = companies(:first_firm)
+    assert_predicate company.contracts, :empty?
+    company.contracts.build
+    assert_not_predicate company.contracts, :empty?
+  end
+
+  def test_collection_size_twice_for_regressions
+    post = posts(:thinking)
+    assert_equal 0, post.readers.size
+    # This test needs a post that has no readers, we assert it to ensure it holds,
+    # but need to reload the post because the very call to #size hides the bug.
+    post.reload
+    post.readers.build
+    size1 = post.readers.size
+    size2 = post.readers.size
+    assert_equal size1, size2
+  end
+
+  def test_build_many
+    company = companies(:first_firm)
+    new_clients = assert_no_queries { company.clients_of_firm.build([{"name" => "Another Client"}, {"name" => "Another Client II"}]) }
+    assert_equal 2, new_clients.size
+  end
+
+  def test_build_followed_by_save_does_not_load_target
+    companies(:first_firm).clients_of_firm.build("name" => "Another Client")
+    assert companies(:first_firm).save
+    assert !companies(:first_firm).clients_of_firm.loaded?
+  end
+
+  def test_build_without_loading_association
+    first_topic = topics(:first)
+    Reply.column_names
+
+    assert_equal 1, first_topic.replies.length
+
+    assert_no_queries do
+      first_topic.replies.build(:title => "Not saved", :content => "Superstars")
+      assert_equal 2, first_topic.replies.size
+    end
+
+    assert_equal 2, first_topic.replies.to_ary.size
+  end
+
+  def test_build_via_block
+    company = companies(:first_firm)
+    new_client = assert_no_queries { company.clients_of_firm.build {|client| client.name = "Another Client" } }
+    assert !company.clients_of_firm.loaded?
+
+    assert_equal "Another Client", new_client.name
+    assert !new_client.persisted?
+    assert_equal new_client, company.clients_of_firm.last
+  end
+
+  def test_build_many_via_block
+    company = companies(:first_firm)
+    new_clients = assert_no_queries do
+      company.clients_of_firm.build([{"name" => "Another Client"}, {"name" => "Another Client II"}]) do |client|
+        client.name = "changed"
+      end
+    end
+
+    assert_equal 2, new_clients.size
+    assert_equal "changed", new_clients.first.name
+    assert_equal "changed", new_clients.last.name
+  end
+
+  def test_create_without_loading_association
+    first_firm  = companies(:first_firm)
+    Firm.column_names
+    Client.column_names
+
+    assert_equal 2, first_firm.clients_of_firm.size
+    first_firm.clients_of_firm.reset
+
+    assert_queries(1) do
+      first_firm.clients_of_firm.create(:name => "Superstars")
+    end
+
+    assert_equal 3, first_firm.clients_of_firm.size
+  end
+
+  def test_create
+    force_signal37_to_load_all_clients_of_firm
+    new_client = companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert new_client.persisted?
+    assert_equal new_client, companies(:first_firm).clients_of_firm.last
+    assert_equal new_client, companies(:first_firm).clients_of_firm(true).last
+  end
+
+  def test_create_many
+    companies(:first_firm).clients_of_firm.create([{"name" => "Another Client"}, {"name" => "Another Client II"}])
+    assert_equal 4, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_create_followed_by_save_does_not_load_target
+    companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert companies(:first_firm).save
+    assert !companies(:first_firm).clients_of_firm.loaded?
+  end
+
+  def test_deleting
+    force_signal37_to_load_all_clients_of_firm
+    companies(:first_firm).clients_of_firm.delete(companies(:first_firm).clients_of_firm.first)
+    assert_equal 1, companies(:first_firm).clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_deleting_before_save
+    new_firm = Firm.new("name" => "A New Firm, Inc.")
+    new_client = new_firm.clients_of_firm.build("name" => "Another Client")
+    assert_equal 1, new_firm.clients_of_firm.size
+    new_firm.clients_of_firm.delete(new_client)
+    assert_equal 0, new_firm.clients_of_firm.size
+  end
+
+  def test_deleting_updates_counter_cache
+    topic = Topic.order("id ASC").first
+    assert_equal topic.replies.to_a.size, topic.replies_count
+
+    topic.replies.delete(topic.replies.first)
+    topic.reload
+    assert_equal topic.replies.to_a.size, topic.replies_count
+  end
+
+  def test_counter_cache_updates_in_memory_after_concat
+    topic = Topic.create title: "Zoom-zoom-zoom"
+
+    topic.replies << Reply.create(title: "re: zoom", content: "speedy quick!")
+    assert_equal 1, topic.replies_count
+    assert_equal 1, topic.replies.size
+    assert_equal 1, topic.reload.replies.size
+  end
+
+  def test_counter_cache_updates_in_memory_after_create
+    topic = Topic.create title: "Zoom-zoom-zoom"
+
+    topic.replies.create!(title: "re: zoom", content: "speedy quick!")
+    assert_equal 1, topic.replies_count
+    assert_equal 1, topic.replies.size
+    assert_equal 1, topic.reload.replies.size
+  end
+
+  def test_counter_cache_updates_in_memory_after_create_with_array
+    topic = Topic.create title: "Zoom-zoom-zoom"
+
+    topic.replies.create!([
+      { title: "re: zoom", content: "speedy quick!" },
+      { title: "re: zoom 2", content: "OMG lol!" },
+    ])
+    assert_equal 2, topic.replies_count
+    assert_equal 2, topic.replies.size
+    assert_equal 2, topic.reload.replies.size
+  end
+
+  def test_pushing_association_updates_counter_cache
+    topic = Topic.order("id ASC").first
+    reply = Reply.create!
+
+    assert_difference "topic.reload.replies_count", 1 do
+      topic.replies << reply
+    end
+  end
+
+  def test_deleting_updates_counter_cache_without_dependent_option
+    post = posts(:welcome)
+
+    assert_difference "post.reload.tags_count", -1 do
+      post.taggings.delete(post.taggings.first)
+    end
+  end
+
+  def test_deleting_updates_counter_cache_with_dependent_delete_all
+    post = posts(:welcome)
+    post.update_columns(taggings_with_delete_all_count: post.tags_count)
+
+    assert_difference "post.reload.taggings_with_delete_all_count", -1 do
+      post.taggings_with_delete_all.delete(post.taggings_with_delete_all.first)
+    end
+  end
+
+  def test_deleting_updates_counter_cache_with_dependent_destroy
+    post = posts(:welcome)
+    post.update_columns(taggings_with_destroy_count: post.tags_count)
+
+    assert_difference "post.reload.taggings_with_destroy_count", -1 do
+      post.taggings_with_destroy.delete(post.taggings_with_destroy.first)
+    end
+  end
+
+  def test_calling_empty_with_counter_cache
+    post = posts(:welcome)
+    assert_queries(0) do
+      assert_not post.comments.empty?
+    end
+  end
+
+  def test_custom_named_counter_cache
+    topic = topics(:first)
+
+    assert_difference "topic.reload.replies_count", -1 do
+      topic.approved_replies.clear
+    end
+  end
+
+  def test_calling_update_attributes_on_id_changes_the_counter_cache
+    topic = Topic.order("id ASC").first
+    original_count = topic.replies.to_a.size
+    assert_equal original_count, topic.replies_count
+
+    first_reply = topic.replies.first
+    first_reply.update_attributes(:parent_id => nil)
+    assert_equal original_count - 1, topic.reload.replies_count
+
+    first_reply.update_attributes(:parent_id => topic.id)
+    assert_equal original_count, topic.reload.replies_count
+  end
+
+  def test_calling_update_attributes_changing_ids_doesnt_change_counter_cache
+    topic1 = Topic.find(1)
+    topic2 = Topic.find(3)
+    original_count1 = topic1.replies.to_a.size
+    original_count2 = topic2.replies.to_a.size
+
+    reply1 = topic1.replies.first
+    reply2 = topic2.replies.first
+
+    reply1.update_attributes(:parent_id => topic2.id)
+    assert_equal original_count1 - 1, topic1.reload.replies_count
+    assert_equal original_count2 + 1, topic2.reload.replies_count
+
+    reply2.update_attributes(:parent_id => topic1.id)
+    assert_equal original_count1, topic1.reload.replies_count
+    assert_equal original_count2, topic2.reload.replies_count
+  end
+
+  def test_deleting_a_collection
+    force_signal37_to_load_all_clients_of_firm
+    companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert_equal 3, companies(:first_firm).clients_of_firm.size
+    companies(:first_firm).clients_of_firm.delete([companies(:first_firm).clients_of_firm[0], companies(:first_firm).clients_of_firm[1], companies(:first_firm).clients_of_firm[2]])
+    assert_equal 0, companies(:first_firm).clients_of_firm.size
+    assert_equal 0, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_delete_all
+    force_signal37_to_load_all_clients_of_firm
+    companies(:first_firm).dependent_clients_of_firm.create("name" => "Another Client")
+    clients = companies(:first_firm).dependent_clients_of_firm.to_a
+    assert_equal 3, clients.count
+
+    assert_difference "Client.count", -(clients.count) do
+      companies(:first_firm).dependent_clients_of_firm.delete_all
+    end
+  end
+
+  def test_delete_all_with_not_yet_loaded_association_collection
+    force_signal37_to_load_all_clients_of_firm
+    companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert_equal 3, companies(:first_firm).clients_of_firm.size
+    companies(:first_firm).clients_of_firm.reset
+    companies(:first_firm).clients_of_firm.delete_all
+    assert_equal 0, companies(:first_firm).clients_of_firm.size
+    assert_equal 0, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_transaction_when_deleting_persisted
+    good = Client.new(:name => "Good")
+    bad  = Client.new(:name => "Bad", :raise_on_destroy => true)
+
+    companies(:first_firm).clients_of_firm = [good, bad]
+
+    begin
+      companies(:first_firm).clients_of_firm.destroy(good, bad)
+    rescue Client::RaisedOnDestroy
+    end
+
+    assert_equal [good, bad], companies(:first_firm).clients_of_firm(true)
+  end
+
+  def test_transaction_when_deleting_new_record
+    assert_no_queries do
+      firm = Firm.new
+      client = Client.new("name" => "New Client")
+      firm.clients_of_firm << client
+      firm.clients_of_firm.destroy(client)
+    end
+  end
+
+  def test_clearing_an_association_collection
+    firm = companies(:first_firm)
+    client_id = firm.clients_of_firm.first.id
+    assert_equal 2, firm.clients_of_firm.size
+
+    firm.clients_of_firm.clear
+
+    assert_equal 0, firm.clients_of_firm.size
+    assert_equal 0, firm.clients_of_firm(true).size
+    assert_equal [], Client.destroyed_client_ids[firm.id]
+
+    # Should not be destroyed since the association is not dependent.
+    assert_nothing_raised do
+      assert_nil Client.find(client_id).firm
+    end
+  end
+
+  def test_clearing_updates_counter_cache
+    topic = Topic.first
+
+    assert_difference 'topic.reload.replies_count', -1 do
+      topic.replies.clear
+    end
+  end
+
+  def test_clearing_updates_counter_cache_when_inverse_counter_cache_is_a_symbol_with_dependent_destroy
+    car = Car.first
+    car.engines.create!
+
+    assert_difference 'car.reload.engines_count', -1 do
+      car.engines.clear
+    end
+  end
+
+  def test_clearing_a_dependent_association_collection
+    firm = companies(:first_firm)
+    client_id = firm.dependent_clients_of_firm.first.id
+    assert_equal 2, firm.dependent_clients_of_firm.size
+    assert_equal 1, Client.find_by_id(client_id).client_of
+
+    # :delete_all is called on each client since the dependent options is :destroy
+    firm.dependent_clients_of_firm.clear
+
+    assert_equal 0, firm.dependent_clients_of_firm.size
+    assert_equal 0, firm.dependent_clients_of_firm(true).size
+    assert_equal [], Client.destroyed_client_ids[firm.id]
+
+    # Should be destroyed since the association is dependent.
+    assert_nil Client.find_by_id(client_id)
+  end
+
+  def test_delete_all_with_option_delete_all
+    firm = companies(:first_firm)
+    client_id = firm.dependent_clients_of_firm.first.id
+    firm.dependent_clients_of_firm.delete_all(:delete_all)
+    assert_nil Client.find_by_id(client_id)
+  end
+
+  def test_delete_all_accepts_limited_parameters
+    firm = companies(:first_firm)
+    assert_raise(ArgumentError) do
+      firm.dependent_clients_of_firm.delete_all(:destroy)
+    end
+  end
+
+  def test_clearing_an_exclusively_dependent_association_collection
+    firm = companies(:first_firm)
+    client_id = firm.exclusively_dependent_clients_of_firm.first.id
+    assert_equal 2, firm.exclusively_dependent_clients_of_firm.size
+
+    assert_equal [], Client.destroyed_client_ids[firm.id]
+
+    # :exclusively_dependent means each client is deleted directly from
+    # the database without looping through them calling destroy.
+    firm.exclusively_dependent_clients_of_firm.clear
+
+    assert_equal 0, firm.exclusively_dependent_clients_of_firm.size
+    assert_equal 0, firm.exclusively_dependent_clients_of_firm(true).size
+    # no destroy-filters should have been called
+    assert_equal [], Client.destroyed_client_ids[firm.id]
+
+    # Should be destroyed since the association is exclusively dependent.
+    assert_nil Client.find_by_id(client_id)
+  end
+
+  def test_dependent_association_respects_optional_conditions_on_delete
+    firm = companies(:odegy)
+    Client.create(:client_of => firm.id, :name => "BigShot Inc.")
+    Client.create(:client_of => firm.id, :name => "SmallTime Inc.")
+    # only one of two clients is included in the association due to the :conditions key
+    assert_equal 2, Client.where(client_of: firm.id).size
+    assert_equal 1, firm.dependent_conditional_clients_of_firm.size
+    firm.destroy
+    # only the correctly associated client should have been deleted
+    assert_equal 1, Client.where(client_of: firm.id).size
+  end
+
+  def test_dependent_association_respects_optional_sanitized_conditions_on_delete
+    firm = companies(:odegy)
+    Client.create(:client_of => firm.id, :name => "BigShot Inc.")
+    Client.create(:client_of => firm.id, :name => "SmallTime Inc.")
+    # only one of two clients is included in the association due to the :conditions key
+    assert_equal 2, Client.where(client_of: firm.id).size
+    assert_equal 1, firm.dependent_sanitized_conditional_clients_of_firm.size
+    firm.destroy
+    # only the correctly associated client should have been deleted
+    assert_equal 1, Client.where(client_of: firm.id).size
+  end
+
+  def test_dependent_association_respects_optional_hash_conditions_on_delete
+    firm = companies(:odegy)
+    Client.create(:client_of => firm.id, :name => "BigShot Inc.")
+    Client.create(:client_of => firm.id, :name => "SmallTime Inc.")
+    # only one of two clients is included in the association due to the :conditions key
+    assert_equal 2, Client.where(client_of: firm.id).size
+    assert_equal 1, firm.dependent_sanitized_conditional_clients_of_firm.size
+    firm.destroy
+    # only the correctly associated client should have been deleted
+    assert_equal 1, Client.where(client_of: firm.id).size
+  end
+
+  def test_delete_all_association_with_primary_key_deletes_correct_records
+    firm = Firm.first
+    # break the vanilla firm_id foreign key
+    assert_equal 3, firm.clients.count
+    firm.clients.first.update_columns(firm_id: nil)
+    assert_equal 2, firm.clients(true).count
+    assert_equal 2, firm.clients_using_primary_key_with_delete_all.count
+    old_record = firm.clients_using_primary_key_with_delete_all.first
+    firm = Firm.first
+    firm.destroy
+    assert_nil Client.find_by_id(old_record.id)
+  end
+
+  def test_creation_respects_hash_condition
+    ms_client = companies(:first_firm).clients_like_ms_with_hash_conditions.build
+
+    assert        ms_client.save
+    assert_equal  'Microsoft', ms_client.name
+
+    another_ms_client = companies(:first_firm).clients_like_ms_with_hash_conditions.create
+
+    assert        another_ms_client.persisted?
+    assert_equal  'Microsoft', another_ms_client.name
+  end
+
+  def test_clearing_without_initial_access
+    firm = companies(:first_firm)
+
+    firm.clients_of_firm.clear
+
+    assert_equal 0, firm.clients_of_firm.size
+    assert_equal 0, firm.clients_of_firm(true).size
+  end
+
+  def test_deleting_a_item_which_is_not_in_the_collection
+    force_signal37_to_load_all_clients_of_firm
+    summit = Client.find_by_name('Summit')
+    companies(:first_firm).clients_of_firm.delete(summit)
+    assert_equal 2, companies(:first_firm).clients_of_firm.size
+    assert_equal 2, companies(:first_firm).clients_of_firm(true).size
+    assert_equal 2, summit.client_of
+  end
+
+  def test_deleting_by_fixnum_id
+    david = Developer.find(1)
+
+    assert_difference 'david.projects.count', -1 do
+      assert_equal 1, david.projects.delete(1).size
+    end
+
+    assert_equal 1, david.projects.size
+  end
+
+  def test_deleting_by_string_id
+    david = Developer.find(1)
+
+    assert_difference 'david.projects.count', -1 do
+      assert_equal 1, david.projects.delete('1').size
+    end
+
+    assert_equal 1, david.projects.size
+  end
+
+  def test_deleting_self_type_mismatch
+    david = Developer.find(1)
+    david.projects.reload
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { david.projects.delete(Project.find(1).developers) }
+  end
+
+  def test_destroying
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_difference "Client.count", -1 do
+      companies(:first_firm).clients_of_firm.destroy(companies(:first_firm).clients_of_firm.first)
+    end
+
+    assert_equal 1, companies(:first_firm).reload.clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_destroying_by_fixnum_id
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_difference "Client.count", -1 do
+      companies(:first_firm).clients_of_firm.destroy(companies(:first_firm).clients_of_firm.first.id)
+    end
+
+    assert_equal 1, companies(:first_firm).reload.clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_destroying_by_string_id
+    force_signal37_to_load_all_clients_of_firm
+
+    assert_difference "Client.count", -1 do
+      companies(:first_firm).clients_of_firm.destroy(companies(:first_firm).clients_of_firm.first.id.to_s)
+    end
+
+    assert_equal 1, companies(:first_firm).reload.clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_destroying_a_collection
+    force_signal37_to_load_all_clients_of_firm
+    companies(:first_firm).clients_of_firm.create("name" => "Another Client")
+    assert_equal 3, companies(:first_firm).clients_of_firm.size
+
+    assert_difference "Client.count", -2 do
+      companies(:first_firm).clients_of_firm.destroy([companies(:first_firm).clients_of_firm[0], companies(:first_firm).clients_of_firm[1]])
+    end
+
+    assert_equal 1, companies(:first_firm).reload.clients_of_firm.size
+    assert_equal 1, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_destroy_all
+    force_signal37_to_load_all_clients_of_firm
+    clients = companies(:first_firm).clients_of_firm.to_a
+    assert !clients.empty?, "37signals has clients after load"
+    destroyed = companies(:first_firm).clients_of_firm.destroy_all
+    assert_equal clients.sort_by(&:id), destroyed.sort_by(&:id)
+    assert destroyed.all? { |client| client.frozen? }, "destroyed clients should be frozen"
+    assert companies(:first_firm).clients_of_firm.empty?, "37signals has no clients after destroy all"
+    assert companies(:first_firm).clients_of_firm(true).empty?, "37signals has no clients after destroy all and refresh"
+  end
+
+  def test_dependence
+    firm = companies(:first_firm)
+    assert_equal 3, firm.clients.size
+    firm.destroy
+    assert Client.all.merge!(:where => "firm_id=#{firm.id}").to_a.empty?
+  end
+
+  def test_dependence_for_associations_with_hash_condition
+    david = authors(:david)
+    assert_difference('Post.count', -1) { assert david.destroy }
+  end
+
+  def test_destroy_dependent_when_deleted_from_association
+    # sometimes tests on Oracle fail if ORDER BY is not provided therefore add always :order with :first
+    firm = Firm.all.merge!(:order => "id").first
+    assert_equal 3, firm.clients.size
+
+    client = firm.clients.first
+    firm.clients.delete(client)
+
+    assert_raise(ActiveRecord::RecordNotFound) { Client.find(client.id) }
+    assert_raise(ActiveRecord::RecordNotFound) { firm.clients.find(client.id) }
+    assert_equal 2, firm.clients.size
+  end
+
+  def test_three_levels_of_dependence
+    topic = Topic.create "title" => "neat and simple"
+    reply = topic.replies.create "title" => "neat and simple", "content" => "still digging it"
+    reply.replies.create "title" => "neat and simple", "content" => "ain't complaining"
+
+    assert_nothing_raised { topic.destroy }
+  end
+
+  uses_transaction :test_dependence_with_transaction_support_on_failure
+  def test_dependence_with_transaction_support_on_failure
+    firm = companies(:first_firm)
+    clients = firm.clients
+    assert_equal 3, clients.length
+    clients.last.instance_eval { def overwrite_to_raise() raise "Trigger rollback" end }
+
+    firm.destroy rescue "do nothing"
+
+    assert_equal 3, Client.all.merge!(:where => "firm_id=#{firm.id}").to_a.size
+  end
+
+  def test_dependence_on_account
+    num_accounts = Account.count
+    companies(:first_firm).destroy
+    assert_equal num_accounts - 1, Account.count
+  end
+
+  def test_depends_and_nullify
+    num_accounts = Account.count
+
+    core = companies(:rails_core)
+    assert_equal accounts(:rails_core_account), core.account
+    assert_equal companies(:leetsoft, :jadedpixel), core.companies
+    core.destroy
+    assert_nil accounts(:rails_core_account).reload.firm_id
+    assert_nil companies(:leetsoft).reload.client_of
+    assert_nil companies(:jadedpixel).reload.client_of
+
+    assert_equal num_accounts, Account.count
+  end
+
+  def test_restrict_with_exception
+    firm = RestrictedWithExceptionFirm.create!(:name => 'restrict')
+    firm.companies.create(:name => 'child')
+
+    assert !firm.companies.empty?
+    assert_raise(ActiveRecord::DeleteRestrictionError) { firm.destroy }
+    assert RestrictedWithExceptionFirm.exists?(:name => 'restrict')
+    assert firm.companies.exists?(:name => 'child')
+  end
+
+  def test_restrict_with_error
+    firm = RestrictedWithErrorFirm.create!(:name => 'restrict')
+    firm.companies.create(:name => 'child')
+
+    assert !firm.companies.empty?
+
+    firm.destroy
+
+    assert !firm.errors.empty?
+
+    assert_equal "Cannot delete record because dependent companies exist", firm.errors[:base].first
+    assert RestrictedWithErrorFirm.exists?(:name => 'restrict')
+    assert firm.companies.exists?(:name => 'child')
+  end
+
+  def test_included_in_collection
+    assert_equal true, companies(:first_firm).clients.include?(Client.find(2))
+  end
+
+  def test_included_in_collection_for_new_records
+    client = Client.create(:name => 'Persisted')
+    assert_nil client.client_of
+    assert_equal false, Firm.new.clients_of_firm.include?(client),
+     'includes a client that does not belong to any firm'
+  end
+
+  def test_adding_array_and_collection
+    assert_nothing_raised { Firm.first.clients + Firm.all.last.clients }
+  end
+
+  def test_replace_with_less
+    firm = Firm.all.merge!(:order => "id").first
+    firm.clients = [companies(:first_client)]
+    assert firm.save, "Could not save firm"
+    firm.reload
+    assert_equal 1, firm.clients.length
+  end
+
+  def test_replace_with_less_and_dependent_nullify
+    num_companies = Company.count
+    companies(:rails_core).companies = []
+    assert_equal num_companies, Company.count
+  end
+
+  def test_replace_with_new
+    firm = Firm.all.merge!(:order => "id").first
+    firm.clients = [companies(:second_client), Client.new("name" => "New Client")]
+    firm.save
+    firm.reload
+    assert_equal 2, firm.clients.length
+    assert_equal false, firm.clients.include?(:first_client)
+  end
+
+  def test_replace_failure
+    firm = companies(:first_firm)
+    account = Account.new
+    orig_accounts = firm.accounts.to_a
+
+    assert !account.valid?
+    assert !orig_accounts.empty?
+    assert_raise ActiveRecord::RecordNotSaved do
+      firm.accounts = [account]
+    end
+    assert_equal orig_accounts, firm.accounts
+  end
+
+  def test_replace_with_same_content
+    firm = Firm.first
+    firm.clients = []
+    firm.save
+
+    assert_queries(0, ignore_none: true) do
+      firm.clients = []
+    end
+  end
+
+  def test_transactions_when_replacing_on_persisted
+    good = Client.new(:name => "Good")
+    bad  = Client.new(:name => "Bad", :raise_on_save => true)
+
+    companies(:first_firm).clients_of_firm = [good]
+
+    begin
+      companies(:first_firm).clients_of_firm = [bad]
+    rescue Client::RaisedOnSave
+    end
+
+    assert_equal [good], companies(:first_firm).clients_of_firm(true)
+  end
+
+  def test_transactions_when_replacing_on_new_record
+    assert_no_queries do
+      firm = Firm.new
+      firm.clients_of_firm = [Client.new("name" => "New Client")]
+    end
+  end
+
+  def test_get_ids
+    assert_equal [companies(:first_client).id, companies(:second_client).id, companies(:another_first_firm_client).id], companies(:first_firm).client_ids
+  end
+
+  def test_get_ids_for_loaded_associations
+    company = companies(:first_firm)
+    company.clients(true)
+    assert_queries(0) do
+      company.client_ids
+      company.client_ids
+    end
+  end
+
+  def test_get_ids_for_unloaded_associations_does_not_load_them
+    company = companies(:first_firm)
+    assert !company.clients.loaded?
+    assert_equal [companies(:first_client).id, companies(:second_client).id, companies(:another_first_firm_client).id], company.client_ids
+    assert !company.clients.loaded?
+  end
+
+  def test_get_ids_ignores_include_option
+    assert_equal [readers(:michael_welcome).id], posts(:welcome).readers_with_person_ids
+  end
+
+  def test_get_ids_for_ordered_association
+    assert_equal [companies(:another_first_firm_client).id, companies(:second_client).id, companies(:first_client).id], companies(:first_firm).clients_ordered_by_name_ids
+  end
+
+  def test_get_ids_for_association_on_new_record_does_not_try_to_find_records
+    Company.columns  # Load schema information so we don't query below
+    Contract.columns # if running just this test.
+
+    company = Company.new
+    assert_queries(0) do
+      company.contract_ids
+    end
+
+    assert_equal [], company.contract_ids
+  end
+
+  def test_set_ids_for_association_on_new_record_applies_association_correctly
+    contract_a = Contract.create!
+    contract_b = Contract.create!
+    Contract.create! # another contract
+    company = Company.new(:name => "Some Company")
+
+    company.contract_ids = [contract_a.id, contract_b.id]
+    assert_equal [contract_a.id, contract_b.id], company.contract_ids
+    assert_equal [contract_a, contract_b], company.contracts
+
+    company.save!
+    assert_equal company, contract_a.reload.company
+    assert_equal company, contract_b.reload.company
+  end
+
+  def test_assign_ids_ignoring_blanks
+    firm = Firm.create!(:name => 'Apple')
+    firm.client_ids = [companies(:first_client).id, nil, companies(:second_client).id, '']
+    firm.save!
+
+    assert_equal 2, firm.clients(true).size
+    assert_equal true, firm.clients.include?(companies(:second_client))
+  end
+
+  def test_get_ids_for_through
+    assert_equal [comments(:eager_other_comment1).id], authors(:mary).comment_ids
+  end
+
+  def test_modifying_a_through_a_has_many_should_raise
+    [
+      lambda { authors(:mary).comment_ids = [comments(:greetings).id, comments(:more_greetings).id] },
+      lambda { authors(:mary).comments = [comments(:greetings), comments(:more_greetings)] },
+      lambda { authors(:mary).comments << Comment.create!(:body => "Yay", :post_id => 424242) },
+      lambda { authors(:mary).comments.delete(authors(:mary).comments.first) },
+    ].each {|block| assert_raise(ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection, &block) }
+  end
+
+  def test_dynamic_find_should_respect_association_order_for_through
+    assert_equal Comment.find(10), authors(:david).comments_desc.where("comments.type = 'SpecialComment'").first
+    assert_equal Comment.find(10), authors(:david).comments_desc.find_by_type('SpecialComment')
+  end
+
+  def test_has_many_through_respects_hash_conditions
+    assert_equal authors(:david).hello_posts, authors(:david).hello_posts_with_hash_conditions
+    assert_equal authors(:david).hello_post_comments, authors(:david).hello_post_comments_with_hash_conditions
+  end
+
+  def test_include_uses_array_include_after_loaded
+    firm = companies(:first_firm)
+    firm.clients.load_target
+
+    client = firm.clients.first
+
+    assert_no_queries do
+      assert firm.clients.loaded?
+      assert_equal true, firm.clients.include?(client)
+    end
+  end
+
+  def test_include_checks_if_record_exists_if_target_not_loaded
+    firm = companies(:first_firm)
+    client = firm.clients.first
+
+    firm.reload
+    assert ! firm.clients.loaded?
+    assert_queries(1) do
+      assert_equal true, firm.clients.include?(client)
+    end
+    assert ! firm.clients.loaded?
+  end
+
+  def test_include_returns_false_for_non_matching_record_to_verify_scoping
+    firm = companies(:first_firm)
+    client = Client.create!(:name => 'Not Associated')
+
+    assert ! firm.clients.loaded?
+    assert_equal false, firm.clients.include?(client)
+  end
+
+  def test_calling_first_nth_or_last_on_association_should_not_load_association
+    firm = companies(:first_firm)
+    firm.clients.first
+    firm.clients.second
+    firm.clients.last
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_first_or_last_on_loaded_association_should_not_fetch_with_query
+    firm = companies(:first_firm)
+    firm.clients.load_target
+    assert firm.clients.loaded?
+
+    assert_no_queries do
+      firm.clients.first
+      assert_equal 2, firm.clients.first(2).size
+      firm.clients.last
+      assert_equal 2, firm.clients.last(2).size
+    end
+  end
+
+  def test_calling_first_or_last_on_existing_record_with_build_should_load_association
+    firm = companies(:first_firm)
+    firm.clients.build(:name => 'Foo')
+    assert !firm.clients.loaded?
+
+    assert_queries 1 do
+      firm.clients.first
+      firm.clients.second
+      firm.clients.last
+    end
+
+    assert firm.clients.loaded?
+  end
+
+  def test_calling_first_nth_or_last_on_existing_record_with_create_should_not_load_association
+    firm = companies(:first_firm)
+    firm.clients.create(:name => 'Foo')
+    assert !firm.clients.loaded?
+
+    assert_queries 3 do
+      firm.clients.first
+      firm.clients.second
+      firm.clients.last
+    end
+
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_first_nth_or_last_on_new_record_should_not_run_queries
+    firm = Firm.new
+
+    assert_no_queries do
+      firm.clients.first
+      firm.clients.second
+      firm.clients.last
+    end
+  end
+
+  def test_custom_primary_key_on_new_record_should_fetch_with_query
+    author = Author.new(:name => "David")
+    assert !author.essays.loaded?
+
+    assert_queries 1 do
+      assert_equal 1, author.essays.size
+    end
+
+    assert_equal author.essays, Essay.where(writer_id: "David")
+  end
+
+  def test_has_many_custom_primary_key
+    david = authors(:david)
+    assert_equal david.essays, Essay.where(writer_id: "David")
+  end
+
+  def test_has_many_assignment_with_custom_primary_key
+    david = people(:david)
+
+    assert_equal ["A Modest Proposal"], david.essays.map(&:name)
+    david.essays = [Essay.create!(name: "Remote Work" )]
+    assert_equal ["Remote Work"], david.essays.map(&:name)
+  end
+
+  def test_blank_custom_primary_key_on_new_record_should_not_run_queries
+    author = Author.new
+    assert !author.essays.loaded?
+
+    assert_queries 0 do
+      assert_equal 0, author.essays.size
+    end
+  end
+
+  def test_calling_first_or_last_with_integer_on_association_should_not_load_association
+    firm = companies(:first_firm)
+    firm.clients.create(:name => 'Foo')
+    assert !firm.clients.loaded?
+
+    assert_queries 2 do
+      firm.clients.first(2)
+      firm.clients.last(2)
+    end
+
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_many_should_count_instead_of_loading_association
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients.many?  # use count query
+    end
+    assert !firm.clients.loaded?
+  end
+
+  def test_calling_many_on_loaded_association_should_not_use_query
+    firm = companies(:first_firm)
+    firm.clients.collect  # force load
+    assert_no_queries { assert firm.clients.many? }
+  end
+
+  def test_calling_many_should_defer_to_collection_if_using_a_block
+    firm = companies(:first_firm)
+    assert_queries(1) do
+      firm.clients.expects(:size).never
+      firm.clients.many? { true }
+    end
+    assert firm.clients.loaded?
+  end
+
+  def test_calling_many_should_return_false_if_none_or_one
+    firm = companies(:another_firm)
+    assert !firm.clients_like_ms.many?
+    assert_equal 0, firm.clients_like_ms.size
+
+    firm = companies(:first_firm)
+    assert !firm.limited_clients.many?
+    assert_equal 1, firm.limited_clients.size
+  end
+
+  def test_calling_many_should_return_true_if_more_than_one
+    firm = companies(:first_firm)
+    assert firm.clients.many?
+    assert_equal 3, firm.clients.size
+  end
+
+  def test_joins_with_namespaced_model_should_use_correct_type
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+
+    firm = Namespaced::Firm.create({ :name => 'Some Company' })
+    firm.clients.create({ :name => 'Some Client' })
+
+    stats = Namespaced::Firm.all.merge!(
+      :select => "#{Namespaced::Firm.table_name}.id, COUNT(#{Namespaced::Client.table_name}.id) AS num_clients",
+      :joins  => :clients,
+      :group  => "#{Namespaced::Firm.table_name}.id"
+    ).find firm.id
+    assert_equal 1, stats.num_clients.to_i
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_association_proxy_transaction_method_starts_transaction_in_association_class
+    Comment.expects(:transaction)
+    Post.first.comments.transaction do
+      # nothing
+    end
+  end
+
+  def test_sending_new_to_association_proxy_should_have_same_effect_as_calling_new
+    client_association = companies(:first_firm).clients
+    assert_equal client_association.new.attributes, client_association.send(:new).attributes
+  end
+
+  def test_respond_to_private_class_methods
+    client_association = companies(:first_firm).clients
+    assert !client_association.respond_to?(:private_method)
+    assert client_association.respond_to?(:private_method, true)
+  end
+
+  def test_creating_using_primary_key
+    firm = Firm.all.merge!(:order => "id").first
+    client = firm.clients_using_primary_key.create!(:name => 'test')
+    assert_equal firm.name, client.firm_name
+  end
+
+  def test_defining_has_many_association_with_delete_all_dependency_lazily_evaluates_target_class
+    ActiveRecord::Reflection::AssociationReflection.any_instance.expects(:class_name).never
+    class_eval(<<-EOF, __FILE__, __LINE__ + 1)
+      class DeleteAllModel < ActiveRecord::Base
+        has_many :nonentities, :dependent => :delete_all
+      end
+    EOF
+  end
+
+  def test_defining_has_many_association_with_nullify_dependency_lazily_evaluates_target_class
+    ActiveRecord::Reflection::AssociationReflection.any_instance.expects(:class_name).never
+    class_eval(<<-EOF, __FILE__, __LINE__ + 1)
+      class NullifyModel < ActiveRecord::Base
+        has_many :nonentities, :dependent => :nullify
+      end
+    EOF
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_has_many_association_with_where_clause
+    new_comment = posts(:welcome).comments.where(:body => "Some content").build
+    assert_equal new_comment.body, "Some content"
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_has_many_association_with_multiple_where_clauses
+    new_comment = posts(:welcome).comments.where(:body => "Some content").where(:type => 'SpecialComment').build
+    assert_equal new_comment.body, "Some content"
+    assert_equal new_comment.type, "SpecialComment"
+    assert_equal new_comment.post_id, posts(:welcome).id
+  end
+
+  def test_include_method_in_has_many_association_should_return_true_for_instance_added_with_build
+    post = Post.new
+    comment = post.comments.build
+    assert_equal true, post.comments.include?(comment)
+  end
+
+  def test_load_target_respects_protected_attributes
+    topic = Topic.create!
+    reply = topic.replies.create(:title => "reply 1")
+    reply.approved = false
+    reply.save!
+
+    # Save with a different object instance, so the instance that's still held
+    # in topic.relies doesn't know about the changed attribute.
+    reply2 = Reply.find(reply.id)
+    reply2.approved = true
+    reply2.save!
+
+    # Force loading the collection from the db. This will merge the existing
+    # object (reply) with what gets loaded from the db (which includes the
+    # changed approved attribute). approved is a protected attribute, so if mass
+    # assignment is used, it won't get updated and will still be false.
+    first = topic.replies.to_a.first
+    assert_equal reply.id, first.id
+    assert_equal true, first.approved?
+  end
+
+  def test_to_a_should_dup_target
+    ary    = topics(:first).replies.to_a
+    target = topics(:first).replies.target
+
+    assert_not_equal target.object_id, ary.object_id
+  end
+
+  def test_merging_with_custom_attribute_writer
+    bulb = Bulb.new(:color => "red")
+    assert_equal "RED!", bulb.color
+
+    car = Car.create!
+    car.bulbs << bulb
+
+    assert_equal "RED!", car.bulbs.to_a.first.color
+  end
+
+  def test_abstract_class_with_polymorphic_has_many
+    post = SubStiPost.create! :title => "fooo", :body => "baa"
+    tagging = Tagging.create! :taggable => post
+    assert_equal [tagging], post.taggings
+  end
+
+  def test_build_with_polymorphic_has_many_does_not_allow_to_override_type_and_id
+    welcome = posts(:welcome)
+    tagging = welcome.taggings.build(:taggable_id => 99, :taggable_type => 'ShouldNotChange')
+
+    assert_equal welcome.id, tagging.taggable_id
+    assert_equal 'Post', tagging.taggable_type
+  end
+
+  def test_dont_call_save_callbacks_twice_on_has_many
+    firm = companies(:first_firm)
+    contract = firm.contracts.create!
+
+    assert_equal 1, contract.hi_count
+    assert_equal 1, contract.bye_count
+  end
+
+  def test_association_attributes_are_available_to_after_initialize
+    car = Car.create(:name => 'honda')
+    bulb = car.bulbs.build
+
+    assert_equal car.id, bulb.attributes_after_initialize['car_id']
+  end
+
+  def test_attributes_are_set_when_initialized_from_has_many_null_relationship
+    car  = Car.new name: 'honda'
+    bulb = car.bulbs.where(name: 'headlight').first_or_initialize
+    assert_equal 'headlight', bulb.name
+  end
+
+  def test_attributes_are_set_when_initialized_from_polymorphic_has_many_null_relationship
+    post    = Post.new title: 'title', body: 'bar'
+    tag     = Tag.create!(name: 'foo')
+
+    tagging = post.taggings.where(tag: tag).first_or_initialize
+
+    assert_equal tag.id, tagging.tag_id
+    assert_equal 'Post', tagging.taggable_type
+  end
+
+  def test_replace
+    car = Car.create(:name => 'honda')
+    bulb1 = car.bulbs.create
+    bulb2 = Bulb.create
+
+    assert_equal [bulb1], car.bulbs
+    car.bulbs.replace([bulb2])
+    assert_equal [bulb2], car.bulbs
+    assert_equal [bulb2], car.reload.bulbs
+  end
+
+  def test_replace_returns_target
+    car = Car.create(:name => 'honda')
+    bulb1 = car.bulbs.create
+    bulb2 = car.bulbs.create
+    bulb3 = Bulb.create
+
+    assert_equal [bulb1, bulb2], car.bulbs
+    result = car.bulbs.replace([bulb3, bulb1])
+    assert_equal [bulb1, bulb3], car.bulbs
+    assert_equal [bulb1, bulb3], result
+  end
+
+  def test_collection_association_with_private_kernel_method
+    firm = companies(:first_firm)
+    assert_equal [accounts(:signals37)], firm.accounts.open
+  end
+
+  test "first_or_initialize adds the record to the association" do
+    firm = Firm.create! name: 'omg'
+    client = firm.clients_of_firm.first_or_initialize
+    assert_equal [client], firm.clients_of_firm
+  end
+
+  test "first_or_create adds the record to the association" do
+    firm = Firm.create! name: 'omg'
+    firm.clients_of_firm.load_target
+    client = firm.clients_of_firm.first_or_create name: 'lol'
+    assert_equal [client], firm.clients_of_firm
+    assert_equal [client], firm.reload.clients_of_firm
+  end
+
+  test "delete_all, when not loaded, doesn't load the records" do
+    post = posts(:welcome)
+
+    assert post.taggings_with_delete_all.count > 0
+    assert !post.taggings_with_delete_all.loaded?
+
+    # 2 queries: one DELETE and another to update the counter cache
+    assert_queries(2) do
+      post.taggings_with_delete_all.delete_all
+    end
+  end
+
+  test "has many associations on new records use null relations" do
+    post = Post.new
+
+    assert_no_queries do
+      assert_equal [], post.comments
+      assert_equal [], post.comments.where(body: 'omg')
+      assert_equal [], post.comments.pluck(:body)
+      assert_equal 0,  post.comments.sum(:id)
+      assert_equal 0,  post.comments.count
+    end
+  end
+
+  test "collection proxy respects default scope" do
+    author = authors(:mary)
+    assert !author.first_posts.exists?
+  end
+
+  test "association with extend option" do
+    post = posts(:welcome)
+    assert_equal "lifo",  post.comments_with_extend.author
+    assert_equal "hello", post.comments_with_extend.greeting
+  end
+
+  test "association with extend option with multiple extensions" do
+    post = posts(:welcome)
+    assert_equal "lifo",  post.comments_with_extend_2.author
+    assert_equal "hello", post.comments_with_extend_2.greeting
+  end
+
+  test "delete record with complex joins" do
+    david = authors(:david)
+
+    post = david.posts.first
+    post.type = 'PostWithSpecialCategorization'
+    post.save
+
+    categorization = post.categorizations.first
+    categorization.special = true
+    categorization.save
+
+    assert_not_equal [], david.posts_with_special_categorizations
+    david.posts_with_special_categorizations = []
+    assert_equal [], david.posts_with_special_categorizations
+  end
+
+  test "does not duplicate associations when used with natural primary keys" do
+    speedometer = Speedometer.create!(id: '4')
+    speedometer.minivans.create!(minivan_id: 'a-van-red' ,name: 'a van', color: 'red')
+
+    assert_equal 1, speedometer.minivans.to_a.size, "Only one association should be present:\n#{speedometer.minivans.to_a}"
+    assert_equal 1, speedometer.reload.minivans.to_a.size
+  end
+
+  test "can unscope the default scope of the associated model" do
+    car = Car.create!
+    bulb1 = Bulb.create! name: "defaulty", car: car
+    bulb2 = Bulb.create! name: "other",    car: car
+
+    assert_equal [bulb1], car.bulbs
+    assert_equal [bulb1, bulb2], car.all_bulbs.sort_by(&:id)
+  end
+
+  test "raises RecordNotDestroyed when replaced child can't be destroyed" do
+    car = Car.create!
+    original_child = FailedBulb.create!(car: car)
+
+    assert_raise(ActiveRecord::RecordNotDestroyed) do
+      car.failed_bulbs = [FailedBulb.create!]
+    end
+
+    assert_equal [original_child], car.reload.failed_bulbs
+  end
+
+  test 'updates counter cache when default scope is given' do
+    topic = DefaultRejectedTopic.create approved: true
+
+    assert_difference "topic.reload.replies_count", 1 do
+      topic.approved_replies.create!
+    end
+  end
+
+  test 'dangerous association name raises ArgumentError' do
+    [:errors, 'errors', :save, 'save'].each do |name|
+      assert_raises(ArgumentError, "Association #{name} should not be allowed") do
+        Class.new(ActiveRecord::Base) do
+          has_many name
+        end
+      end
+    end
+  end
+
+  test 'passes custom context validation to validate children' do
+    pirate = FamousPirate.new
+    pirate.famous_ships << ship = FamousShip.new
+
+    assert pirate.valid?
+    assert_not pirate.valid?(:conference)
+    assert_equal "can't be blank", ship.errors[:name].first
+  end
+
+  test 'association with instance dependent scope' do
+    bob = authors(:bob)
+    Post.create!(title: "signed post by bob", body: "stuff", author: authors(:bob))
+    Post.create!(title: "anonymous post", body: "more stuff", author: authors(:bob))
+    assert_equal ["misc post by bob", "other post by bob",
+                  "signed post by bob"], bob.posts_with_signature.map(&:title).sort
+
+    assert_equal [], authors(:david).posts_with_signature.map(&:title)
+  end
+end
diff --git a/activerecord/test/cases/associations/has_many_through_associations_test.rb b/activerecord/test/cases/associations/has_many_through_associations_test.rb
new file mode 100644
index 0000000000..a85e020f0c
--- /dev/null
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -0,0 +1,1169 @@
+require "cases/helper"
+require 'models/post'
+require 'models/person'
+require 'models/reference'
+require 'models/job'
+require 'models/reader'
+require 'models/comment'
+require 'models/rating'
+require 'models/tag'
+require 'models/tagging'
+require 'models/author'
+require 'models/owner'
+require 'models/pet'
+require 'models/toy'
+require 'models/contract'
+require 'models/company'
+require 'models/developer'
+require 'models/subscriber'
+require 'models/book'
+require 'models/subscription'
+require 'models/essay'
+require 'models/category'
+require 'models/categorization'
+require 'models/member'
+require 'models/membership'
+require 'models/club'
+
+class HasManyThroughAssociationsTest < ActiveRecord::TestCase
+  fixtures :posts, :readers, :people, :comments, :authors, :categories, :taggings, :tags,
+           :owners, :pets, :toys, :jobs, :references, :companies, :members, :author_addresses,
+           :subscribers, :books, :subscriptions, :developers, :categorizations, :essays,
+           :categories_posts, :clubs, :memberships
+
+  # Dummies to force column loads so query counts are clean.
+  def setup
+    Person.create :first_name => 'gummy'
+    Reader.create :person_id => 0, :post_id => 0
+  end
+
+  def test_preload_sti_rhs_class
+    developers = Developer.includes(:firms).all.to_a
+    assert_no_queries do
+      developers.each { |d| d.firms }
+    end
+  end
+
+  def test_preload_sti_middle_relation
+    club = Club.create!(name: 'Aaron cool banana club')
+    member1 = Member.create!(name: 'Aaron')
+    member2 = Member.create!(name: 'Cat')
+
+    SuperMembership.create! club: club, member: member1
+    CurrentMembership.create! club: club, member: member2
+
+    club1 = Club.includes(:members).find_by_id club.id
+    assert_equal [member1, member2].sort_by(&:id),
+                 club1.members.sort_by(&:id)
+  end
+
+  def make_model(name)
+    Class.new(ActiveRecord::Base) { define_singleton_method(:name) { name } }
+  end
+
+  def test_ordered_habtm
+    person_prime = Class.new(ActiveRecord::Base) do
+      def self.name; 'Person'; end
+
+      has_many :readers
+      has_many :posts, -> { order('posts.id DESC') }, :through => :readers
+    end
+    posts = person_prime.includes(:posts).first.posts
+
+    assert_operator posts.length, :>, 1
+    posts.each_cons(2) do |left,right|
+      assert_operator left.id, :>, right.id
+    end
+  end
+
+  def test_singleton_has_many_through
+    book         = make_model "Book"
+    subscription = make_model "Subscription"
+    subscriber   = make_model "Subscriber"
+
+    subscriber.primary_key = 'nick'
+    subscription.belongs_to :book,       class: book
+    subscription.belongs_to :subscriber, class: subscriber
+
+    book.has_many :subscriptions, class: subscription
+    book.has_many :subscribers, through: :subscriptions, class: subscriber
+
+    anonbook = book.first
+    namebook = Book.find anonbook.id
+
+    assert_operator anonbook.subscribers.count, :>, 0
+    anonbook.subscribers.each do |s|
+      assert_instance_of subscriber, s
+    end
+    assert_equal namebook.subscribers.map(&:id).sort,
+                 anonbook.subscribers.map(&:id).sort
+  end
+
+  def test_no_pk_join_table_append
+    lesson, _, student = make_no_pk_hm_t
+
+    sicp = lesson.new(:name => "SICP")
+    ben = student.new(:name => "Ben Bitdiddle")
+    sicp.students << ben
+    assert sicp.save!
+  end
+
+  def test_no_pk_join_table_delete
+    lesson, lesson_student, student = make_no_pk_hm_t
+
+    sicp = lesson.new(:name => "SICP")
+    ben = student.new(:name => "Ben Bitdiddle")
+    louis = student.new(:name => "Louis Reasoner")
+    sicp.students << ben
+    sicp.students << louis
+    assert sicp.save!
+
+    sicp.students.reload
+    assert_operator lesson_student.count, :>=, 2
+    assert_no_difference('student.count') do
+      assert_difference('lesson_student.count', -2) do
+        sicp.students.destroy(*student.all.to_a)
+      end
+    end
+  end
+
+  def test_no_pk_join_model_callbacks
+    lesson, lesson_student, student = make_no_pk_hm_t
+
+    after_destroy_called = false
+    lesson_student.after_destroy do
+      after_destroy_called = true
+    end
+
+    sicp = lesson.new(:name => "SICP")
+    ben = student.new(:name => "Ben Bitdiddle")
+    sicp.students << ben
+    assert sicp.save!
+
+    sicp.students.reload
+    sicp.students.destroy(*student.all.to_a)
+    assert after_destroy_called, "after destroy should be called"
+  end
+
+  def make_no_pk_hm_t
+    lesson = make_model 'Lesson'
+    student = make_model 'Student'
+
+    lesson_student = make_model 'LessonStudent'
+    lesson_student.table_name = 'lessons_students'
+
+    lesson_student.belongs_to :lesson, :class => lesson
+    lesson_student.belongs_to :student, :class => student
+    lesson.has_many :lesson_students, :class => lesson_student
+    lesson.has_many :students, :through => :lesson_students, :class => student
+    [lesson, lesson_student, student]
+  end
+
+  def test_pk_is_not_required_for_join
+    post  = Post.includes(:scategories).first
+    post2 = Post.includes(:categories).first
+
+    assert_operator post.categories.length, :>, 0
+    assert_equal post2.categories, post.categories
+  end
+
+  def test_include?
+    person = Person.new
+    post = Post.new
+    person.posts << post
+    assert person.posts.include?(post)
+  end
+
+  def test_associate_existing
+    post   = posts(:thinking)
+    person = people(:david)
+
+    assert_queries(1) do
+      post.people << person
+    end
+
+    assert_queries(1) do
+      assert post.people.include?(person)
+    end
+
+    assert post.reload.people(true).include?(person)
+  end
+
+  def test_delete_all_for_with_dependent_option_destroy
+    person = people(:david)
+    assert_equal 1, person.jobs_with_dependent_destroy.count
+
+    assert_no_difference 'Job.count' do
+      assert_difference 'Reference.count', -1 do
+        person.reload.jobs_with_dependent_destroy.delete_all
+      end
+    end
+  end
+
+  def test_delete_all_for_with_dependent_option_nullify
+    person = people(:david)
+    assert_equal 1, person.jobs_with_dependent_nullify.count
+
+    assert_no_difference 'Job.count' do
+      assert_no_difference 'Reference.count' do
+        person.reload.jobs_with_dependent_nullify.delete_all
+      end
+    end
+  end
+
+  def test_delete_all_for_with_dependent_option_delete_all
+    person = people(:david)
+    assert_equal 1, person.jobs_with_dependent_delete_all.count
+
+    assert_no_difference 'Job.count' do
+      assert_difference 'Reference.count', -1 do
+        person.reload.jobs_with_dependent_delete_all.delete_all
+      end
+    end
+  end
+
+  def test_concat
+    person = people(:david)
+    post   = posts(:thinking)
+    post.people.concat [person]
+    assert_equal 1, post.people.size
+    assert_equal 1, post.people(true).size
+  end
+
+  def test_associate_existing_record_twice_should_add_to_target_twice
+    post   = posts(:thinking)
+    person = people(:david)
+
+    assert_difference 'post.people.to_a.count', 2 do
+      post.people << person
+      post.people << person
+    end
+  end
+
+  def test_associate_existing_record_twice_should_add_records_twice
+    post   = posts(:thinking)
+    person = people(:david)
+
+    assert_difference 'post.people.count', 2 do
+      post.people << person
+      post.people << person
+    end
+  end
+
+  def test_add_two_instance_and_then_deleting
+    post   = posts(:thinking)
+    person = people(:david)
+
+    post.people << person
+    post.people << person
+
+    counts = ['post.people.count', 'post.people.to_a.count', 'post.readers.count', 'post.readers.to_a.count']
+    assert_difference counts, -2 do
+      post.people.delete(person)
+    end
+
+    assert !post.people.reload.include?(person)
+  end
+
+  def test_associating_new
+    assert_queries(1) { posts(:thinking) }
+    new_person = nil # so block binding catches it
+
+    assert_queries(0) do
+      new_person = Person.new :first_name => 'bob'
+    end
+
+    # Associating new records always saves them
+    # Thus, 1 query for the new person record, 1 query for the new join table record
+    assert_queries(2) do
+      posts(:thinking).people << new_person
+    end
+
+    assert_queries(1) do
+      assert posts(:thinking).people.include?(new_person)
+    end
+
+    assert posts(:thinking).reload.people(true).include?(new_person)
+  end
+
+  def test_associate_new_by_building
+    assert_queries(1) { posts(:thinking) }
+
+    assert_queries(0) do
+      posts(:thinking).people.build(:first_name => "Bob")
+      posts(:thinking).people.new(:first_name => "Ted")
+    end
+
+    # Should only need to load the association once
+    assert_queries(1) do
+      assert posts(:thinking).people.collect(&:first_name).include?("Bob")
+      assert posts(:thinking).people.collect(&:first_name).include?("Ted")
+    end
+
+    # 2 queries for each new record (1 to save the record itself, 1 for the join model)
+    #    * 2 new records = 4
+    # + 1 query to save the actual post = 5
+    assert_queries(5) do
+      posts(:thinking).body += '-changed'
+      posts(:thinking).save
+    end
+
+    assert posts(:thinking).reload.people(true).collect(&:first_name).include?("Bob")
+    assert posts(:thinking).reload.people(true).collect(&:first_name).include?("Ted")
+  end
+
+  def test_build_then_save_with_has_many_inverse
+    post   = posts(:thinking)
+    person = post.people.build(:first_name => "Bob")
+    person.save
+    post.reload
+
+    assert post.people.include?(person)
+  end
+
+  def test_build_then_save_with_has_one_inverse
+    post   = posts(:thinking)
+    person = post.single_people.build(:first_name => "Bob")
+    person.save
+    post.reload
+
+    assert post.single_people.include?(person)
+  end
+
+  def test_both_parent_ids_set_when_saving_new
+    post = Post.new(title: 'Hello', body: 'world')
+    person = Person.new(first_name: 'Sean')
+
+    post.people = [person]
+    post.save
+
+    assert post.id
+    assert person.id
+    assert_equal post.id, post.readers.first.post_id
+    assert_equal person.id, post.readers.first.person_id
+  end
+
+  def test_delete_association
+    assert_queries(2){posts(:welcome);people(:michael); }
+
+    assert_queries(1) do
+      posts(:welcome).people.delete(people(:michael))
+    end
+
+    assert_queries(1) do
+      assert posts(:welcome).people.empty?
+    end
+
+    assert posts(:welcome).reload.people(true).empty?
+  end
+
+  def test_destroy_association
+    assert_no_difference "Person.count" do
+      assert_difference "Reader.count", -1 do
+        posts(:welcome).people.destroy(people(:michael))
+      end
+    end
+
+    assert posts(:welcome).reload.people.empty?
+    assert posts(:welcome).people(true).empty?
+  end
+
+  def test_destroy_all
+    assert_no_difference "Person.count" do
+      assert_difference "Reader.count", -1 do
+        posts(:welcome).people.destroy_all
+      end
+    end
+
+    assert posts(:welcome).reload.people.empty?
+    assert posts(:welcome).people(true).empty?
+  end
+
+  def test_should_raise_exception_for_destroying_mismatching_records
+    assert_no_difference ["Person.count", "Reader.count"] do
+      assert_raise(ActiveRecord::AssociationTypeMismatch) { posts(:welcome).people.destroy(posts(:thinking)) }
+    end
+  end
+
+  def test_delete_through_belongs_to_with_dependent_nullify
+    Reference.make_comments = true
+
+    person    = people(:michael)
+    job       = jobs(:magician)
+    reference = Reference.where(:job_id => job.id, :person_id => person.id).first
+
+    assert_no_difference ['Job.count', 'Reference.count'] do
+      assert_difference 'person.jobs.count', -1 do
+        person.jobs_with_dependent_nullify.delete(job)
+      end
+    end
+
+    assert_equal nil, reference.reload.job_id
+  ensure
+    Reference.make_comments = false
+  end
+
+  def test_delete_through_belongs_to_with_dependent_delete_all
+    Reference.make_comments = true
+
+    person = people(:michael)
+    job    = jobs(:magician)
+
+    # Make sure we're not deleting everything
+    assert person.jobs.count >= 2
+
+    assert_no_difference 'Job.count' do
+      assert_difference ['person.jobs.count', 'Reference.count'], -1 do
+        person.jobs_with_dependent_delete_all.delete(job)
+      end
+    end
+
+    # Check that the destroy callback on Reference did not run
+    assert_equal nil, person.reload.comments
+  ensure
+    Reference.make_comments = false
+  end
+
+  def test_delete_through_belongs_to_with_dependent_destroy
+    Reference.make_comments = true
+
+    person = people(:michael)
+    job    = jobs(:magician)
+
+    # Make sure we're not deleting everything
+    assert person.jobs.count >= 2
+
+    assert_no_difference 'Job.count' do
+      assert_difference ['person.jobs.count', 'Reference.count'], -1 do
+        person.jobs_with_dependent_destroy.delete(job)
+      end
+    end
+
+    # Check that the destroy callback on Reference ran
+    assert_equal "Reference destroyed", person.reload.comments
+  ensure
+    Reference.make_comments = false
+  end
+
+  def test_belongs_to_with_dependent_destroy
+    person = PersonWithDependentDestroyJobs.find(1)
+
+    # Create a reference which is not linked to a job. This should not be destroyed.
+    person.references.create!
+
+    assert_no_difference 'Job.count' do
+      assert_difference 'Reference.count', -person.jobs.count do
+        person.destroy
+      end
+    end
+  end
+
+  def test_belongs_to_with_dependent_delete_all
+    person = PersonWithDependentDeleteAllJobs.find(1)
+
+    # Create a reference which is not linked to a job. This should not be destroyed.
+    person.references.create!
+
+    assert_no_difference 'Job.count' do
+      assert_difference 'Reference.count', -person.jobs.count do
+        person.destroy
+      end
+    end
+  end
+
+  def test_belongs_to_with_dependent_nullify
+    person = PersonWithDependentNullifyJobs.find(1)
+
+    references = person.references.to_a
+
+    assert_no_difference ['Reference.count', 'Job.count'] do
+      person.destroy
+    end
+
+    references.each do |reference|
+      assert_equal nil, reference.reload.job_id
+    end
+  end
+
+  def test_update_counter_caches_on_delete
+    post = posts(:welcome)
+    tag  = post.tags.create!(:name => 'doomed')
+
+    assert_difference ['post.reload.tags_count'], -1 do
+      posts(:welcome).tags.delete(tag)
+    end
+  end
+
+  def test_update_counter_caches_on_delete_with_dependent_destroy
+    post = posts(:welcome)
+    tag  = post.tags.create!(:name => 'doomed')
+    post.update_columns(tags_with_destroy_count: post.tags.count)
+
+    assert_difference ['post.reload.tags_with_destroy_count'], -1 do
+      posts(:welcome).tags_with_destroy.delete(tag)
+    end
+  end
+
+  def test_update_counter_caches_on_delete_with_dependent_nullify
+    post = posts(:welcome)
+    tag  = post.tags.create!(:name => 'doomed')
+    post.update_columns(tags_with_nullify_count: post.tags.count)
+
+    assert_no_difference 'post.reload.tags_count' do
+      assert_difference 'post.reload.tags_with_nullify_count', -1 do
+        posts(:welcome).tags_with_nullify.delete(tag)
+      end
+    end
+  end
+
+  def test_update_counter_caches_on_replace_association
+    post = posts(:welcome)
+    tag  = post.tags.create!(:name => 'doomed')
+    tag.tagged_posts << posts(:thinking)
+
+    tag.tagged_posts = []
+    post.reload
+
+    assert_equal(post.taggings.count, post.tags_count)
+  end
+
+  def test_update_counter_caches_on_destroy
+    post = posts(:welcome)
+    tag  = post.tags.create!(name: 'doomed')
+
+    assert_difference 'post.reload.tags_count', -1 do
+      tag.tagged_posts.destroy(post)
+    end
+  end
+
+  def test_replace_association
+    assert_queries(4){posts(:welcome);people(:david);people(:michael); posts(:welcome).people(true)}
+
+    # 1 query to delete the existing reader (michael)
+    # 1 query to associate the new reader (david)
+    assert_queries(2) do
+      posts(:welcome).people = [people(:david)]
+    end
+
+    assert_queries(0){
+      assert posts(:welcome).people.include?(people(:david))
+      assert !posts(:welcome).people.include?(people(:michael))
+    }
+
+    assert posts(:welcome).reload.people(true).include?(people(:david))
+    assert !posts(:welcome).reload.people(true).include?(people(:michael))
+  end
+
+  def test_replace_order_is_preserved
+    posts(:welcome).people.clear
+    posts(:welcome).people = [people(:david), people(:michael)]
+    assert_equal [people(:david).id, people(:michael).id], posts(:welcome).readers.order('id').map(&:person_id)
+
+    # Test the inverse order in case the first success was a coincidence
+    posts(:welcome).people.clear
+    posts(:welcome).people = [people(:michael), people(:david)]
+    assert_equal [people(:michael).id, people(:david).id], posts(:welcome).readers.order('id').map(&:person_id)
+  end
+
+  def test_replace_by_id_order_is_preserved
+    posts(:welcome).people.clear
+    posts(:welcome).person_ids = [people(:david).id, people(:michael).id]
+    assert_equal [people(:david).id, people(:michael).id], posts(:welcome).readers.order('id').map(&:person_id)
+
+    # Test the inverse order in case the first success was a coincidence
+    posts(:welcome).people.clear
+    posts(:welcome).person_ids = [people(:michael).id, people(:david).id]
+    assert_equal [people(:michael).id, people(:david).id], posts(:welcome).readers.order('id').map(&:person_id)
+  end
+
+  def test_associate_with_create
+    assert_queries(1) { posts(:thinking) }
+
+    # 1 query for the new record, 1 for the join table record
+    # No need to update the actual collection yet!
+    assert_queries(2) do
+      posts(:thinking).people.create(:first_name=>"Jeb")
+    end
+
+    # *Now* we actually need the collection so it's loaded
+    assert_queries(1) do
+      assert posts(:thinking).people.collect(&:first_name).include?("Jeb")
+    end
+
+    assert posts(:thinking).reload.people(true).collect(&:first_name).include?("Jeb")
+  end
+
+  def test_associate_with_create_and_no_options
+    peeps = posts(:thinking).people.count
+    posts(:thinking).people.create(:first_name => 'foo')
+    assert_equal peeps + 1, posts(:thinking).people.count
+  end
+
+  def test_associate_with_create_with_through_having_conditions
+    impatient_people = posts(:thinking).impatient_people.count
+    posts(:thinking).impatient_people.create!(:first_name => 'foo')
+    assert_equal impatient_people + 1, posts(:thinking).impatient_people.count
+  end
+
+  def test_associate_with_create_exclamation_and_no_options
+    peeps = posts(:thinking).people.count
+    posts(:thinking).people.create!(:first_name => 'foo')
+    assert_equal peeps + 1, posts(:thinking).people.count
+  end
+
+  def test_create_on_new_record
+    p = Post.new
+
+    assert_raises(ActiveRecord::RecordNotSaved) { p.people.create(:first_name => "mew") }
+    assert_raises(ActiveRecord::RecordNotSaved) { p.people.create!(:first_name => "snow") }
+  end
+
+  def test_associate_with_create_and_invalid_options
+    firm = companies(:first_firm)
+    assert_no_difference('firm.developers.count') { assert_nothing_raised { firm.developers.create(:name => '0') } }
+  end
+
+  def test_associate_with_create_and_valid_options
+    firm = companies(:first_firm)
+    assert_difference('firm.developers.count', 1) { firm.developers.create(:name => 'developer') }
+  end
+
+  def test_associate_with_create_bang_and_invalid_options
+    firm = companies(:first_firm)
+    assert_no_difference('firm.developers.count') { assert_raises(ActiveRecord::RecordInvalid) { firm.developers.create!(:name => '0') } }
+  end
+
+  def test_associate_with_create_bang_and_valid_options
+    firm = companies(:first_firm)
+    assert_difference('firm.developers.count', 1) { firm.developers.create!(:name => 'developer') }
+  end
+
+  def test_push_with_invalid_record
+    firm = companies(:first_firm)
+    assert_raises(ActiveRecord::RecordInvalid) { firm.developers << Developer.new(:name => '0') }
+  end
+
+  def test_push_with_invalid_join_record
+    repair_validations(Contract) do
+      Contract.validate {|r| r.errors[:base] << 'Invalid Contract' }
+
+      firm = companies(:first_firm)
+      lifo = Developer.new(:name => 'lifo')
+      assert_raises(ActiveRecord::RecordInvalid) { firm.developers << lifo }
+
+      lifo = Developer.create!(:name => 'lifo')
+      assert_raises(ActiveRecord::RecordInvalid) { firm.developers << lifo }
+    end
+  end
+
+  def test_clear_associations
+    assert_queries(2) { posts(:welcome);posts(:welcome).people(true) }
+
+    assert_queries(1) do
+      posts(:welcome).people.clear
+    end
+
+    assert_queries(0) do
+      assert posts(:welcome).people.empty?
+    end
+
+    assert posts(:welcome).reload.people(true).empty?
+  end
+
+  def test_association_callback_ordering
+    Post.reset_log
+    log = Post.log
+    post = posts(:thinking)
+
+    post.people_with_callbacks << people(:michael)
+    assert_equal [
+      [:added, :before, "Michael"],
+      [:added, :after, "Michael"]
+    ], log.last(2)
+
+    post.people_with_callbacks.push(people(:david), Person.create!(:first_name => "Bob"), Person.new(:first_name => "Lary"))
+    assert_equal [
+      [:added, :before, "David"],
+      [:added, :after, "David"],
+      [:added, :before, "Bob"],
+      [:added, :after, "Bob"],
+      [:added, :before, "Lary"],
+      [:added, :after, "Lary"]
+    ],log.last(6)
+
+    post.people_with_callbacks.build(:first_name => "Ted")
+    assert_equal [
+      [:added, :before, "Ted"],
+      [:added, :after, "Ted"]
+    ], log.last(2)
+
+    post.people_with_callbacks.create(:first_name => "Sam")
+    assert_equal [
+      [:added, :before, "Sam"],
+      [:added, :after, "Sam"]
+    ], log.last(2)
+
+    post.people_with_callbacks = [people(:michael),people(:david), Person.new(:first_name => "Julian"), Person.create!(:first_name => "Roger")]
+    assert_equal((%w(Ted Bob Sam Lary) * 2).sort, log[-12..-5].collect(&:last).sort)
+    assert_equal [
+      [:added, :before, "Julian"],
+      [:added, :after, "Julian"],
+      [:added, :before, "Roger"],
+      [:added, :after, "Roger"]
+    ], log.last(4)
+  end
+
+  def test_dynamic_find_should_respect_association_include
+    # SQL error in sort clause if :include is not included
+    # due to Unknown column 'comments.id'
+    assert Person.find(1).posts_with_comments_sorted_by_comment_id.find_by_title('Welcome to the weblog')
+  end
+
+  def test_count_with_include_should_alias_join_table
+    assert_equal 2, people(:michael).posts.includes(:readers).count
+  end
+
+  def test_inner_join_with_quoted_table_name
+    assert_equal 2, people(:michael).jobs.size
+  end
+
+  def test_get_ids
+    assert_equal [posts(:welcome).id, posts(:authorless).id].sort, people(:michael).post_ids.sort
+  end
+
+  def test_get_ids_for_has_many_through_with_conditions_should_not_preload
+    Tagging.create!(:taggable_type => 'Post', :taggable_id => posts(:welcome).id, :tag => tags(:misc))
+    ActiveRecord::Associations::Preloader.expects(:new).never
+    posts(:welcome).misc_tag_ids
+  end
+
+  def test_get_ids_for_loaded_associations
+    person = people(:michael)
+    person.posts(true)
+    assert_queries(0) do
+      person.post_ids
+      person.post_ids
+    end
+  end
+
+  def test_get_ids_for_unloaded_associations_does_not_load_them
+    person = people(:michael)
+    assert !person.posts.loaded?
+    assert_equal [posts(:welcome).id, posts(:authorless).id].sort, person.post_ids.sort
+    assert !person.posts.loaded?
+  end
+
+  def test_association_proxy_transaction_method_starts_transaction_in_association_class
+    Tag.expects(:transaction)
+    Post.first.tags.transaction do
+      # nothing
+    end
+  end
+
+  def test_has_many_association_through_a_belongs_to_association_where_the_association_doesnt_exist
+    post = Post.create!(:title => "TITLE", :body => "BODY")
+    assert_equal [], post.author_favorites
+  end
+
+  def test_has_many_association_through_a_belongs_to_association
+    author = authors(:mary)
+    post = Post.create!(:author => author, :title => "TITLE", :body => "BODY")
+    author.author_favorites.create(:favorite_author_id => 1)
+    author.author_favorites.create(:favorite_author_id => 2)
+    author.author_favorites.create(:favorite_author_id => 3)
+    assert_equal post.author.author_favorites, post.author_favorites
+  end
+
+  def test_merge_join_association_with_has_many_through_association_proxy
+    author = authors(:mary)
+    assert_nothing_raised { author.comments.ratings.to_sql }
+  end
+
+  def test_has_many_association_through_a_has_many_association_with_nonstandard_primary_keys
+    assert_equal 2, owners(:blackbeard).toys.count
+  end
+
+  def test_find_on_has_many_association_collection_with_include_and_conditions
+    post_with_no_comments = people(:michael).posts_with_no_comments.first
+    assert_equal post_with_no_comments, posts(:authorless)
+  end
+
+  def test_has_many_through_has_one_reflection
+    assert_equal [comments(:eager_sti_on_associations_vs_comment)], authors(:david).very_special_comments
+  end
+
+  def test_modifying_has_many_through_has_one_reflection_should_raise
+    [
+      lambda { authors(:david).very_special_comments = [VerySpecialComment.create!(:body => "Gorp!", :post_id => 1011), VerySpecialComment.create!(:body => "Eep!", :post_id => 1012)] },
+      lambda { authors(:david).very_special_comments << VerySpecialComment.create!(:body => "Hoohah!", :post_id => 1013) },
+      lambda { authors(:david).very_special_comments.delete(authors(:david).very_special_comments.first) },
+    ].each {|block| assert_raise(ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection, &block) }
+  end
+
+  def test_has_many_association_through_a_has_many_association_to_self
+    sarah = Person.create!(:first_name => 'Sarah', :primary_contact_id => people(:susan).id, :gender => 'F', :number1_fan_id => 1)
+    john = Person.create!(:first_name => 'John', :primary_contact_id => sarah.id, :gender => 'M', :number1_fan_id => 1)
+    assert_equal sarah.agents, [john]
+    assert_equal people(:susan).agents.flat_map(&:agents), people(:susan).agents_of_agents
+  end
+
+  def test_associate_existing_with_nonstandard_primary_key_on_belongs_to
+    Categorization.create(:author => authors(:mary), :named_category_name => categories(:general).name)
+    assert_equal categories(:general), authors(:mary).named_categories.first
+  end
+
+  def test_collection_build_with_nonstandard_primary_key_on_belongs_to
+    author   = authors(:mary)
+    category = author.named_categories.build(:name => "Primary")
+    author.save
+    assert Categorization.exists?(:author_id => author.id, :named_category_name => category.name)
+    assert author.named_categories(true).include?(category)
+  end
+
+  def test_collection_create_with_nonstandard_primary_key_on_belongs_to
+    author   = authors(:mary)
+    category = author.named_categories.create(:name => "Primary")
+    assert Categorization.exists?(:author_id => author.id, :named_category_name => category.name)
+    assert author.named_categories(true).include?(category)
+  end
+
+  def test_collection_exists
+    author   = authors(:mary)
+    category = Category.create!(author_ids: [author.id], name: "Primary")
+    assert category.authors.exists?(id: author.id)
+    assert category.reload.authors.exists?(id: author.id)
+  end
+
+  def test_collection_delete_with_nonstandard_primary_key_on_belongs_to
+    author   = authors(:mary)
+    category = author.named_categories.create(:name => "Primary")
+    author.named_categories.delete(category)
+    assert !Categorization.exists?(:author_id => author.id, :named_category_name => category.name)
+    assert author.named_categories(true).empty?
+  end
+
+  def test_collection_singular_ids_getter_with_string_primary_keys
+    book = books(:awdr)
+    assert_equal 2, book.subscriber_ids.size
+    assert_equal [subscribers(:first).nick, subscribers(:second).nick].sort, book.subscriber_ids.sort
+  end
+
+  def test_collection_singular_ids_setter
+    company = companies(:rails_core)
+    dev = Developer.first
+
+    company.developer_ids = [dev.id]
+    assert_equal [dev], company.developers
+  end
+
+  def test_collection_singular_ids_setter_with_string_primary_keys
+    assert_nothing_raised do
+      book = books(:awdr)
+      book.subscriber_ids = [subscribers(:second).nick]
+      assert_equal [subscribers(:second)], book.subscribers(true)
+
+      book.subscriber_ids = []
+      assert_equal [], book.subscribers(true)
+    end
+
+  end
+
+  def test_collection_singular_ids_setter_raises_exception_when_invalid_ids_set
+    company = companies(:rails_core)
+    ids =  [Developer.first.id, -9999]
+    assert_raises(ActiveRecord::RecordNotFound) {company.developer_ids= ids}
+  end
+
+  def test_build_a_model_from_hm_through_association_with_where_clause
+    assert_nothing_raised { books(:awdr).subscribers.where(:nick => "marklazz").build }
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_hm_through_association_with_where_clause
+    new_subscriber = books(:awdr).subscribers.where(:nick => "marklazz").build
+    assert_equal new_subscriber.nick, "marklazz"
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_hm_through_association_with_multiple_where_clauses
+    new_subscriber = books(:awdr).subscribers.where(:nick => "marklazz").where(:name => 'Marcelo Giorgi').build
+    assert_equal new_subscriber.nick, "marklazz"
+    assert_equal new_subscriber.name, "Marcelo Giorgi"
+  end
+
+  def test_include_method_in_association_through_should_return_true_for_instance_added_with_build
+    person = Person.new
+    reference = person.references.build
+    job = reference.build_job
+    assert person.jobs.include?(job)
+  end
+
+  def test_include_method_in_association_through_should_return_true_for_instance_added_with_nested_builds
+    author = Author.new
+    post = author.posts.build
+    comment = post.comments.build
+    assert author.comments.include?(comment)
+  end
+
+  def test_through_association_readonly_should_be_false
+    assert !people(:michael).posts.first.readonly?
+    assert !people(:michael).posts.to_a.first.readonly?
+  end
+
+  def test_can_update_through_association
+    assert_nothing_raised do
+      people(:michael).posts.first.update!(title: "Can write")
+    end
+  end
+
+  def test_has_many_through_polymorphic_with_primary_key_option
+    assert_equal [categories(:general)], authors(:david).essay_categories
+
+    authors = Author.joins(:essay_categories).where('categories.id' => categories(:general).id)
+    assert_equal authors(:david), authors.first
+
+    assert_equal [owners(:blackbeard)], authors(:david).essay_owners
+
+    authors = Author.joins(:essay_owners).where("owners.name = 'blackbeard'")
+    assert_equal authors(:david), authors.first
+  end
+
+  def test_has_many_through_with_primary_key_option
+    assert_equal [categories(:general)], authors(:david).essay_categories_2
+
+    authors = Author.joins(:essay_categories_2).where('categories.id' => categories(:general).id)
+    assert_equal authors(:david), authors.first
+  end
+
+  def test_size_of_through_association_should_increase_correctly_when_has_many_association_is_added
+    post = posts(:thinking)
+    readers = post.readers.size
+    post.people << people(:michael)
+    assert_equal readers + 1, post.readers.size
+  end
+
+  def test_has_many_through_with_default_scope_on_join_model
+    assert_equal posts(:welcome).comments.order('id').to_a, authors(:david).comments_on_first_posts
+  end
+
+  def test_create_has_many_through_with_default_scope_on_join_model
+    category = authors(:david).special_categories.create(:name => "Foo")
+    assert_equal 1, category.categorizations.where(:special => true).count
+  end
+
+  def test_joining_has_many_through_with_uniq
+    mary = Author.joins(:unique_categorized_posts).where(:id => authors(:mary).id).first
+    assert_equal 1, mary.unique_categorized_posts.length
+    assert_equal 1, mary.unique_categorized_post_ids.length
+  end
+
+  def test_joining_has_many_through_belongs_to
+    posts = Post.joins(:author_categorizations).order('posts.id').
+                 where('categorizations.id' => categorizations(:mary_thinking_sti).id)
+
+    assert_equal [posts(:eager_other), posts(:misc_by_mary), posts(:other_by_mary)], posts
+  end
+
+  def test_select_chosen_fields_only
+    author = authors(:david)
+    assert_equal ['body', 'id'].sort, author.comments.select('comments.body').first.attributes.keys.sort
+  end
+
+  def test_get_has_many_through_belongs_to_ids_with_conditions
+    assert_equal [categories(:general).id], authors(:mary).categories_like_general_ids
+  end
+
+  def test_get_collection_singular_ids_on_has_many_through_with_conditions_and_include
+    person = Person.first
+    assert_equal person.posts_with_no_comment_ids, person.posts_with_no_comments.map(&:id)
+  end
+
+  def test_count_has_many_through_with_named_scope
+    assert_equal 2, authors(:mary).categories.count
+    assert_equal 1, authors(:mary).categories.general.count
+  end
+
+  def test_has_many_through_belongs_to_should_update_when_the_through_foreign_key_changes
+    post = posts(:eager_other)
+
+    post.author_categorizations
+    proxy = post.send(:association_instance_get, :author_categorizations)
+
+    assert !proxy.stale_target?
+    assert_equal authors(:mary).categorizations.sort_by(&:id), post.author_categorizations.sort_by(&:id)
+
+    post.author_id = authors(:david).id
+
+    assert proxy.stale_target?
+    assert_equal authors(:david).categorizations.sort_by(&:id), post.author_categorizations.sort_by(&:id)
+  end
+
+  def test_create_with_conditions_hash_on_through_association
+    member = members(:groucho)
+    club   = member.clubs.create!
+
+    assert_equal true, club.reload.membership.favourite
+  end
+
+  def test_deleting_from_has_many_through_a_belongs_to_should_not_try_to_update_counter
+    post    = posts(:welcome)
+    address = author_addresses(:david_address)
+
+    assert post.author_addresses.include?(address)
+    post.author_addresses.delete(address)
+    assert post[:author_count].nil?
+  end
+
+  def test_primary_key_option_on_source
+    post     = posts(:welcome)
+    category = categories(:general)
+    Categorization.create!(:post_id => post.id, :named_category_name => category.name)
+
+    assert_equal [category], post.named_categories
+    assert_equal [category.name], post.named_category_ids # checks when target loaded
+    assert_equal [category.name], post.reload.named_category_ids # checks when target no loaded
+  end
+
+  def test_create_should_not_raise_exception_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << 'Invalid Categorization' }
+      Category.create(:name => 'Fishing', :authors => [Author.first])
+    end
+  end
+
+  def test_save_should_not_raise_exception_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << 'Invalid Categorization' }
+      c = Category.create(:name => 'Fishing', :authors => [Author.first])
+      c.save
+    end
+  end
+
+  def test_assign_array_to_new_record_builds_join_records
+    c = Category.new(:name => 'Fishing', :authors => [Author.first])
+    assert_equal 1, c.categorizations.size
+  end
+
+  def test_create_bang_should_raise_exception_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << 'Invalid Categorization' }
+      assert_raises(ActiveRecord::RecordInvalid) do
+        Category.create!(:name => 'Fishing', :authors => [Author.first])
+      end
+    end
+  end
+
+  def test_save_bang_should_raise_exception_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << 'Invalid Categorization' }
+      c = Category.new(:name => 'Fishing', :authors => [Author.first])
+      assert_raises(ActiveRecord::RecordInvalid) do
+        c.save!
+      end
+    end
+  end
+
+  def test_create_bang_returns_falsy_when_join_record_has_errors
+    repair_validations(Categorization) do
+      Categorization.validate { |r| r.errors[:base] << 'Invalid Categorization' }
+      c = Category.new(:name => 'Fishing', :authors => [Author.first])
+      assert !c.save
+    end
+  end
+
+  def test_preloading_empty_through_association_via_joins
+    person = Person.create!(:first_name => "Gaga")
+    person = Person.where(:id => person.id).where('readers.id = 1 or 1=1').references(:readers).includes(:posts).to_a.first
+
+    assert person.posts.loaded?, 'person.posts should be loaded'
+    assert_equal [], person.posts
+  end
+
+  def test_explicitly_joining_join_table
+    assert_equal owners(:blackbeard).toys, owners(:blackbeard).toys.with_pet
+  end
+
+  def test_has_many_through_with_polymorphic_source
+    post = tags(:general).tagged_posts.create! :title => "foo", :body => "bar"
+    assert_equal [tags(:general)], post.reload.tags
+  end
+
+  def test_has_many_through_obeys_order_on_through_association
+    owner = owners(:blackbeard)
+    assert owner.toys.to_sql.include?("pets.name desc")
+    assert_equal ["parrot", "bulbul"], owner.toys.map { |r| r.pet.name }
+  end
+
+  def test_has_many_through_associations_on_new_records_use_null_relations
+    person = Person.new
+
+    assert_no_queries do
+      assert_equal [], person.posts
+      assert_equal [], person.posts.where(body: 'omg')
+      assert_equal [], person.posts.pluck(:body)
+      assert_equal 0,  person.posts.sum(:tags_count)
+      assert_equal 0,  person.posts.count
+    end
+  end
+
+  def test_has_many_through_with_default_scope_on_the_target
+    person = people(:michael)
+    assert_equal [posts(:thinking)], person.first_posts
+
+    readers(:michael_authorless).update(first_post_id: 1)
+    assert_equal [posts(:thinking)], person.reload.first_posts
+  end
+
+  def test_has_many_through_with_includes_in_through_association_scope
+    assert_not_empty posts(:welcome).author_address_extra_with_address
+  end
+
+  def test_insert_records_via_has_many_through_association_with_scope
+    club = Club.create!
+    member = Member.create!
+    Membership.create!(club: club, member: member)
+
+    club.favourites << member
+    assert_equal [member], club.favourites
+
+    club.reload
+    assert_equal [member], club.favourites
+  end
+
+  def test_has_many_through_unscope_default_scope
+    post = Post.create!(:title => 'Beaches', :body => "I like beaches!")
+    Reader.create! :person => people(:david), :post => post
+    LazyReader.create! :person => people(:susan), :post => post
+
+    assert_equal 2, post.people.to_a.size
+    assert_equal 1, post.lazy_people.to_a.size
+
+    assert_equal 2, post.lazy_readers_unscope_skimmers.to_a.size
+    assert_equal 2, post.lazy_people_unscope_skimmers.to_a.size
+  end
+
+  def test_has_many_through_add_with_sti_middle_relation
+    club = SuperClub.create!(name: 'Fight Club')
+    member = Member.create!(name: 'Tyler Durden')
+
+    club.members << member
+    assert_equal 1, SuperMembership.where(member_id: member.id, club_id: club.id).count
+  end
+
+  class ClubWithCallbacks < ActiveRecord::Base
+    self.table_name = 'clubs'
+    after_create :add_a_member
+
+    has_many :memberships, inverse_of: :club, foreign_key: :club_id
+    has_many :members, through: :memberships
+
+    def add_a_member
+      members << Member.last
+    end
+  end
+
+  def test_has_many_with_callback_before_association
+    Member.create!
+    club = ClubWithCallbacks.create!
+
+    assert_equal 1, club.reload.memberships.count
+  end
+end
diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
new file mode 100644
index 0000000000..a4650ccdf2
--- /dev/null
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -0,0 +1,577 @@
+require "cases/helper"
+require 'models/developer'
+require 'models/project'
+require 'models/company'
+require 'models/ship'
+require 'models/pirate'
+require 'models/car'
+require 'models/bulb'
+require 'models/author'
+require 'models/post'
+
+class HasOneAssociationsTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+  fixtures :accounts, :companies, :developers, :projects, :developers_projects, :ships, :pirates
+
+  def setup
+    Account.destroyed_account_ids.clear
+  end
+
+  def test_has_one
+    assert_equal companies(:first_firm).account, Account.find(1)
+    assert_equal Account.find(1).credit_limit, companies(:first_firm).account.credit_limit
+  end
+
+  def test_has_one_does_not_use_order_by
+    ActiveRecord::SQLCounter.clear_log
+    companies(:first_firm).account
+  ensure
+    assert ActiveRecord::SQLCounter.log_all.all? { |sql| /order by/i !~ sql }, 'ORDER BY was used in the query'
+  end
+
+  def test_has_one_cache_nils
+    firm = companies(:another_firm)
+    assert_queries(1) { assert_nil firm.account }
+    assert_queries(0) { assert_nil firm.account }
+
+    firms = Firm.all.merge!(:includes => :account).to_a
+    assert_queries(0) { firms.each(&:account) }
+  end
+
+  def test_with_select
+    assert_equal Firm.find(1).account_with_select.attributes.size, 2
+    assert_equal Firm.all.merge!(:includes => :account_with_select).find(1).account_with_select.attributes.size, 2
+  end
+
+  def test_finding_using_primary_key
+    firm = companies(:first_firm)
+    assert_equal Account.find_by_firm_id(firm.id), firm.account
+    firm.firm_id = companies(:rails_core).id
+    assert_equal accounts(:rails_core_account), firm.account_using_primary_key
+  end
+
+  def test_update_with_foreign_and_primary_keys
+    firm = companies(:first_firm)
+    account = firm.account_using_foreign_and_primary_keys
+    assert_equal Account.find_by_firm_name(firm.name), account
+    firm.save
+    firm.reload
+    assert_equal account, firm.account_using_foreign_and_primary_keys
+  end
+
+  def test_can_marshal_has_one_association_with_nil_target
+    firm = Firm.new
+    assert_nothing_raised do
+      assert_equal firm.attributes, Marshal.load(Marshal.dump(firm)).attributes
+    end
+
+    firm.account
+    assert_nothing_raised do
+      assert_equal firm.attributes, Marshal.load(Marshal.dump(firm)).attributes
+    end
+  end
+
+  def test_proxy_assignment
+    company = companies(:first_firm)
+    assert_nothing_raised { company.account = company.account }
+  end
+
+  def test_type_mismatch
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).account = 1 }
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { companies(:first_firm).account = Project.find(1) }
+  end
+
+  def test_natural_assignment
+    apple = Firm.create("name" => "Apple")
+    citibank = Account.create("credit_limit" => 10)
+    apple.account = citibank
+    assert_equal apple.id, citibank.firm_id
+  end
+
+  def test_natural_assignment_to_nil
+    old_account_id = companies(:first_firm).account.id
+    companies(:first_firm).account = nil
+    companies(:first_firm).save
+    assert_nil companies(:first_firm).account
+    # account is dependent, therefore is destroyed when reference to owner is lost
+    assert_raise(ActiveRecord::RecordNotFound) { Account.find(old_account_id) }
+  end
+
+  def test_nullification_on_association_change
+    firm = companies(:rails_core)
+    old_account_id = firm.account.id
+    firm.account = Account.new(:credit_limit => 5)
+    # account is dependent with nullify, therefore its firm_id should be nil
+    assert_nil Account.find(old_account_id).firm_id
+  end
+
+  def test_natural_assignment_to_nil_after_destroy
+    firm = companies(:rails_core)
+    old_account_id = firm.account.id
+    firm.account.destroy
+    firm.account = nil
+    assert_nil companies(:rails_core).account
+    assert_raise(ActiveRecord::RecordNotFound) { Account.find(old_account_id) }
+  end
+
+  def test_association_change_calls_delete
+    companies(:first_firm).deletable_account = Account.new(:credit_limit => 5)
+    assert_equal [], Account.destroyed_account_ids[companies(:first_firm).id]
+  end
+
+  def test_association_change_calls_destroy
+    companies(:first_firm).account = Account.new(:credit_limit => 5)
+    assert_equal [companies(:first_firm).id], Account.destroyed_account_ids[companies(:first_firm).id]
+  end
+
+  def test_natural_assignment_to_already_associated_record
+    company = companies(:first_firm)
+    account = accounts(:signals37)
+    assert_equal company.account, account
+    company.account = account
+    company.reload
+    account.reload
+    assert_equal company.account, account
+  end
+
+  def test_dependence
+    num_accounts = Account.count
+
+    firm = Firm.find(1)
+    assert_not_nil firm.account
+    account_id = firm.account.id
+    assert_equal [], Account.destroyed_account_ids[firm.id]
+
+    firm.destroy
+    assert_equal num_accounts - 1, Account.count
+    assert_equal [account_id], Account.destroyed_account_ids[firm.id]
+  end
+
+  def test_exclusive_dependence
+    num_accounts = Account.count
+
+    firm = ExclusivelyDependentFirm.find(9)
+    assert_not_nil firm.account
+    assert_equal [], Account.destroyed_account_ids[firm.id]
+
+    firm.destroy
+    assert_equal num_accounts - 1, Account.count
+    assert_equal [], Account.destroyed_account_ids[firm.id]
+  end
+
+  def test_dependence_with_nil_associate
+    firm = DependentFirm.new(:name => 'nullify')
+    firm.save!
+    assert_nothing_raised { firm.destroy }
+  end
+
+  def test_restrict_with_exception
+    firm = RestrictedWithExceptionFirm.create!(:name => 'restrict')
+    firm.create_account(:credit_limit => 10)
+
+    assert_not_nil firm.account
+
+    assert_raise(ActiveRecord::DeleteRestrictionError) { firm.destroy }
+    assert RestrictedWithExceptionFirm.exists?(:name => 'restrict')
+    assert firm.account.present?
+  end
+
+  def test_restrict_with_error
+    firm = RestrictedWithErrorFirm.create!(:name => 'restrict')
+    firm.create_account(:credit_limit => 10)
+
+    assert_not_nil firm.account
+
+    firm.destroy
+
+    assert !firm.errors.empty?
+    assert_equal "Cannot delete record because a dependent account exists", firm.errors[:base].first
+    assert RestrictedWithErrorFirm.exists?(:name => 'restrict')
+    assert firm.account.present?
+  end
+
+  def test_successful_build_association
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.save
+
+    account = firm.build_account("credit_limit" => 1000)
+    assert account.save
+    assert_equal account, firm.account
+  end
+
+  def test_build_association_dont_create_transaction
+    assert_no_queries {
+      Firm.new.build_account
+    }
+  end
+
+  def test_building_the_associated_object_with_implicit_sti_base_class
+    firm = DependentFirm.new
+    company = firm.build_company
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_associated_object_with_explicit_sti_base_class
+    firm = DependentFirm.new
+    company = firm.build_company(:type => "Company")
+    assert_kind_of Company, company, "Expected #{company.class} to be a Company"
+  end
+
+  def test_building_the_associated_object_with_sti_subclass
+    firm = DependentFirm.new
+    company = firm.build_company(:type => "Client")
+    assert_kind_of Client, company, "Expected #{company.class} to be a Client"
+  end
+
+  def test_building_the_associated_object_with_an_invalid_type
+    firm = DependentFirm.new
+    assert_raise(ActiveRecord::SubclassNotFound) { firm.build_company(:type => "Invalid") }
+  end
+
+  def test_building_the_associated_object_with_an_unrelated_type
+    firm = DependentFirm.new
+    assert_raise(ActiveRecord::SubclassNotFound) { firm.build_company(:type => "Account") }
+  end
+
+  def test_build_and_create_should_not_happen_within_scope
+    pirate = pirates(:blackbeard)
+    scoped_count = pirate.association(:foo_bulb).scope.where_values.count
+
+    bulb = pirate.build_foo_bulb
+    assert_not_equal scoped_count, bulb.scope_after_initialize.where_values.count
+
+    bulb = pirate.create_foo_bulb
+    assert_not_equal scoped_count, bulb.scope_after_initialize.where_values.count
+
+    bulb = pirate.create_foo_bulb!
+    assert_not_equal scoped_count, bulb.scope_after_initialize.where_values.count
+  end
+
+  def test_create_association
+    firm = Firm.create(:name => "GlobalMegaCorp")
+    account = firm.create_account(:credit_limit => 1000)
+    assert_equal account, firm.reload.account
+  end
+
+  def test_create_association_with_bang
+    firm = Firm.create(:name => "GlobalMegaCorp")
+    account = firm.create_account!(:credit_limit => 1000)
+    assert_equal account, firm.reload.account
+  end
+
+  def test_create_association_with_bang_failing
+    firm = Firm.create(:name => "GlobalMegaCorp")
+    assert_raise ActiveRecord::RecordInvalid do
+      firm.create_account!
+    end
+    account = firm.account
+    assert_not_nil account
+    account.credit_limit = 5
+    account.save
+    assert_equal account, firm.reload.account
+  end
+
+  def test_build
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.save
+
+    firm.account = account = Account.new("credit_limit" => 1000)
+    assert_equal account, firm.account
+    assert account.save
+    assert_equal account, firm.account
+  end
+
+  def test_create
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.save
+    firm.account = account = Account.create("credit_limit" => 1000)
+    assert_equal account, firm.account
+  end
+
+  def test_create_before_save
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.account = account = Account.create("credit_limit" => 1000)
+    assert_equal account, firm.account
+  end
+
+  def test_dependence_with_missing_association
+    Account.destroy_all
+    firm = Firm.find(1)
+    assert_nil firm.account
+    firm.destroy
+  end
+
+  def test_dependence_with_missing_association_and_nullify
+    Account.destroy_all
+    firm = DependentFirm.first
+    assert_nil firm.account
+    firm.destroy
+  end
+
+  def test_finding_with_interpolated_condition
+    firm = Firm.first
+    superior = firm.clients.create(:name => 'SuperiorCo')
+    superior.rating = 10
+    superior.save
+    assert_equal 10, firm.clients_with_interpolated_conditions.first.rating
+  end
+
+  def test_assignment_before_child_saved
+    firm = Firm.find(1)
+    firm.account = a = Account.new("credit_limit" => 1000)
+    assert a.persisted?
+    assert_equal a, firm.account
+    assert_equal a, firm.account
+    assert_equal a, firm.account(true)
+  end
+
+  def test_save_still_works_after_accessing_nil_has_one
+    jp = Company.new :name => 'Jaded Pixel'
+    jp.dummy_account.nil?
+
+    assert_nothing_raised do
+      jp.save!
+    end
+  end
+
+  def test_cant_save_readonly_association
+    assert_raise(ActiveRecord::ReadOnlyRecord) { companies(:first_firm).readonly_account.save!  }
+    assert companies(:first_firm).readonly_account.readonly?
+  end
+
+  def test_has_one_proxy_should_not_respond_to_private_methods
+    assert_raise(NoMethodError) { accounts(:signals37).private_method }
+    assert_raise(NoMethodError) { companies(:first_firm).account.private_method }
+  end
+
+  def test_has_one_proxy_should_respond_to_private_methods_via_send
+    accounts(:signals37).send(:private_method)
+    companies(:first_firm).account.send(:private_method)
+  end
+
+  def test_save_of_record_with_loaded_has_one
+    @firm = companies(:first_firm)
+    assert_not_nil @firm.account
+
+    assert_nothing_raised do
+      Firm.find(@firm.id).save!
+      Firm.all.merge!(:includes => :account).find(@firm.id).save!
+    end
+
+    @firm.account.destroy
+
+    assert_nothing_raised do
+      Firm.find(@firm.id).save!
+      Firm.all.merge!(:includes => :account).find(@firm.id).save!
+    end
+  end
+
+  def test_build_respects_hash_condition
+    account = companies(:first_firm).build_account_limit_500_with_hash_conditions
+    assert account.save
+    assert_equal 500, account.credit_limit
+  end
+
+  def test_create_respects_hash_condition
+    account = companies(:first_firm).create_account_limit_500_with_hash_conditions
+    assert       account.persisted?
+    assert_equal 500, account.credit_limit
+  end
+
+  def test_attributes_are_being_set_when_initialized_from_has_one_association_with_where_clause
+    new_account = companies(:first_firm).build_account(:firm_name => 'Account')
+    assert_equal new_account.firm_name, "Account"
+  end
+
+  def test_creation_failure_without_dependent_option
+    pirate = pirates(:blackbeard)
+    orig_ship = pirate.ship
+
+    assert_equal ships(:black_pearl), orig_ship
+    new_ship = pirate.create_ship
+    assert_not_equal ships(:black_pearl), new_ship
+    assert_equal new_ship, pirate.ship
+    assert new_ship.new_record?
+    assert_nil orig_ship.pirate_id
+    assert !orig_ship.changed? # check it was saved
+  end
+
+  def test_creation_failure_with_dependent_option
+    pirate = pirates(:blackbeard).becomes(DestructivePirate)
+    orig_ship = pirate.dependent_ship
+
+    new_ship = pirate.create_dependent_ship
+    assert new_ship.new_record?
+    assert orig_ship.destroyed?
+  end
+
+  def test_creation_failure_due_to_new_record_should_raise_error
+    pirate = pirates(:redbeard)
+    new_ship = Ship.new
+
+    assert_raise(ActiveRecord::RecordNotSaved) do
+      pirate.ship = new_ship
+    end
+    assert_nil pirate.ship
+    assert_nil new_ship.pirate_id
+  end
+
+  def test_replacement_failure_due_to_existing_record_should_raise_error
+    pirate = pirates(:blackbeard)
+    pirate.ship.name = nil
+
+    assert !pirate.ship.valid?
+    assert_raise(ActiveRecord::RecordNotSaved) do
+      pirate.ship = ships(:interceptor)
+    end
+    assert_equal ships(:black_pearl), pirate.ship
+    assert_equal pirate.id, pirate.ship.pirate_id
+  end
+
+  def test_replacement_failure_due_to_new_record_should_raise_error
+    pirate = pirates(:blackbeard)
+    new_ship = Ship.new
+
+    assert_raise(ActiveRecord::RecordNotSaved) do
+      pirate.ship = new_ship
+    end
+    assert_equal ships(:black_pearl), pirate.ship
+    assert_equal pirate.id, pirate.ship.pirate_id
+    assert_equal pirate.id, ships(:black_pearl).reload.pirate_id
+    assert_nil new_ship.pirate_id
+  end
+
+  def test_association_keys_bypass_attribute_protection
+    car = Car.create(:name => 'honda')
+
+    bulb = car.build_bulb
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.build_bulb :car_id => car.id + 1
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.create_bulb
+    assert_equal car.id, bulb.car_id
+
+    bulb = car.create_bulb :car_id => car.id + 1
+    assert_equal car.id, bulb.car_id
+  end
+
+  def test_association_protect_foreign_key
+    pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+
+    ship = pirate.build_ship
+    assert_equal pirate.id, ship.pirate_id
+
+    ship = pirate.build_ship :pirate_id => pirate.id + 1
+    assert_equal pirate.id, ship.pirate_id
+
+    ship = pirate.create_ship
+    assert_equal pirate.id, ship.pirate_id
+
+    ship = pirate.create_ship :pirate_id => pirate.id + 1
+    assert_equal pirate.id, ship.pirate_id
+  end
+
+  def test_build_with_block
+    car = Car.create(:name => 'honda')
+
+    bulb = car.build_bulb{ |b| b.color = 'Red' }
+    assert_equal 'RED!', bulb.color
+  end
+
+  def test_create_with_block
+    car = Car.create(:name => 'honda')
+
+    bulb = car.create_bulb{ |b| b.color = 'Red' }
+    assert_equal 'RED!', bulb.color
+  end
+
+  def test_create_bang_with_block
+    car = Car.create(:name => 'honda')
+
+    bulb = car.create_bulb!{ |b| b.color = 'Red' }
+    assert_equal 'RED!', bulb.color
+  end
+
+  def test_association_attributes_are_available_to_after_initialize
+    car = Car.create(:name => 'honda')
+    bulb = car.create_bulb
+
+    assert_equal car.id, bulb.attributes_after_initialize['car_id']
+  end
+
+  def test_has_one_transaction
+    company = companies(:first_firm)
+    account = Account.find(1)
+
+    company.account # force loading
+    assert_no_queries { company.account = account }
+
+    company.account = nil
+    assert_no_queries { company.account = nil }
+    account = Account.find(2)
+    assert_queries { company.account = account }
+
+    assert_no_queries { Firm.new.account = account }
+  end
+
+  def test_has_one_assignment_dont_trigger_save_on_change_of_same_object
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    ship = pirate.build_ship(name: 'old name')
+    ship.save!
+
+    ship.name = 'new name'
+    assert ship.changed?
+    assert_queries(1) do
+      # One query for updating name, not triggering query for updating pirate_id
+      pirate.ship = ship
+    end
+
+    assert_equal 'new name', pirate.ship.reload.name
+  end
+
+  def test_has_one_assignment_triggers_save_on_change_on_replacing_object
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    ship = pirate.build_ship(name: 'old name')
+    ship.save!
+
+    new_ship = Ship.create(name: 'new name')
+    assert_queries(2) do
+      # One query for updating name and second query for updating pirate_id
+      pirate.ship = new_ship
+    end
+
+    assert_equal 'new name', pirate.ship.reload.name
+  end
+
+  def test_has_one_autosave_with_primary_key_manually_set
+    post = Post.create(id: 1234, title: "Some title", body: 'Some content')
+    author = Author.new(id: 33, name: 'Hank Moody')
+
+    author.post = post
+    author.save
+    author.reload
+
+    assert_not_nil author.post
+    assert_equal author.post, post
+  end
+
+  def test_has_one_relationship_cannot_have_a_counter_cache
+    assert_raise(ArgumentError) do
+      Class.new(ActiveRecord::Base) do
+        has_one :thing, counter_cache: true
+      end
+    end
+  end
+
+  test 'dangerous association name raises ArgumentError' do
+    [:errors, 'errors', :save, 'save'].each do |name|
+      assert_raises(ArgumentError, "Association #{name} should not be allowed") do
+        Class.new(ActiveRecord::Base) do
+          has_one name
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/associations/has_one_through_associations_test.rb b/activerecord/test/cases/associations/has_one_through_associations_test.rb
new file mode 100644
index 0000000000..089cb0a3a2
--- /dev/null
+++ b/activerecord/test/cases/associations/has_one_through_associations_test.rb
@@ -0,0 +1,340 @@
+require "cases/helper"
+require 'models/club'
+require 'models/member_type'
+require 'models/member'
+require 'models/membership'
+require 'models/sponsor'
+require 'models/organization'
+require 'models/member_detail'
+require 'models/minivan'
+require 'models/dashboard'
+require 'models/speedometer'
+require 'models/category'
+require 'models/author'
+require 'models/essay'
+require 'models/owner'
+require 'models/post'
+require 'models/comment'
+
+class HasOneThroughAssociationsTest < ActiveRecord::TestCase
+  fixtures :member_types, :members, :clubs, :memberships, :sponsors, :organizations, :minivans,
+           :dashboards, :speedometers, :authors, :posts, :comments, :categories, :essays, :owners
+
+  def setup
+    @member = members(:groucho)
+  end
+
+  def test_has_one_through_with_has_one
+    assert_equal clubs(:boring_club), @member.club
+  end
+
+  def test_creating_association_creates_through_record
+    new_member = Member.create(:name => "Chris")
+    new_member.club = Club.create(:name => "LRUG")
+    assert_not_nil new_member.current_membership
+    assert_not_nil new_member.club
+  end
+
+  def test_creating_association_builds_through_record_for_new
+    new_member = Member.new(:name => "Jane")
+    new_member.club = clubs(:moustache_club)
+    assert new_member.current_membership
+    assert_equal clubs(:moustache_club), new_member.current_membership.club
+    assert_equal clubs(:moustache_club), new_member.club
+    assert new_member.save
+    assert_equal clubs(:moustache_club), new_member.club
+  end
+
+  def test_creating_association_sets_both_parent_ids_for_new
+    member = Member.new(name: 'Sean Griffin')
+    club = Club.new(name: 'Da Club')
+
+    member.club = club
+
+    member.save!
+
+    assert member.id
+    assert club.id
+    assert_equal member.id, member.current_membership.member_id
+    assert_equal club.id, member.current_membership.club_id
+  end
+
+  def test_replace_target_record
+    new_club = Club.create(:name => "Marx Bros")
+    @member.club = new_club
+    @member.reload
+    assert_equal new_club, @member.club
+  end
+
+  def test_replacing_target_record_deletes_old_association
+    assert_no_difference "Membership.count" do
+      new_club = Club.create(:name => "Bananarama")
+      @member.club = new_club
+      @member.reload
+    end
+  end
+
+  def test_set_record_to_nil_should_delete_association
+    @member.club = nil
+    @member.reload
+    assert_equal nil, @member.current_membership
+    assert_nil @member.club
+  end
+
+  def test_has_one_through_polymorphic
+    assert_equal clubs(:moustache_club), @member.sponsor_club
+  end
+
+  def test_has_one_through_eager_loading
+    members = assert_queries(3) do #base table, through table, clubs table
+      Member.all.merge!(:includes => :club, :where => ["name = ?", "Groucho Marx"]).to_a
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries {members[0].club}
+  end
+
+  def test_has_one_through_eager_loading_through_polymorphic
+    members = assert_queries(3) do #base table, through table, clubs table
+      Member.all.merge!(:includes => :sponsor_club, :where => ["name = ?", "Groucho Marx"]).to_a
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries {members[0].sponsor_club}
+  end
+
+  def test_has_one_through_with_conditions_eager_loading
+    # conditions on the through table
+    assert_equal clubs(:moustache_club), Member.all.merge!(:includes => :favourite_club).find(@member.id).favourite_club
+    memberships(:membership_of_favourite_club).update_columns(favourite: false)
+    assert_equal nil,                    Member.all.merge!(:includes => :favourite_club).find(@member.id).reload.favourite_club
+
+    # conditions on the source table
+    assert_equal clubs(:moustache_club), Member.all.merge!(:includes => :hairy_club).find(@member.id).hairy_club
+    clubs(:moustache_club).update_columns(name: "Association of Clean-Shaven Persons")
+    assert_equal nil,                    Member.all.merge!(:includes => :hairy_club).find(@member.id).reload.hairy_club
+  end
+
+  def test_has_one_through_polymorphic_with_source_type
+    assert_equal members(:groucho), clubs(:moustache_club).sponsored_member
+  end
+
+  def test_eager_has_one_through_polymorphic_with_source_type
+    clubs = Club.all.merge!(:includes => :sponsored_member, :where => ["name = ?","Moustache and Eyebrow Fancier Club"]).to_a
+    # Only the eyebrow fanciers club has a sponsored_member
+    assert_not_nil assert_no_queries {clubs[0].sponsored_member}
+  end
+
+  def test_has_one_through_nonpreload_eagerloading
+    members = assert_queries(1) do
+      Member.all.merge!(:includes => :club, :where => ["members.name = ?", "Groucho Marx"], :order => 'clubs.name').to_a #force fallback
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries {members[0].club}
+  end
+
+  def test_has_one_through_nonpreload_eager_loading_through_polymorphic
+    members = assert_queries(1) do
+      Member.all.merge!(:includes => :sponsor_club, :where => ["members.name = ?", "Groucho Marx"], :order => 'clubs.name').to_a #force fallback
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries {members[0].sponsor_club}
+  end
+
+  def test_has_one_through_nonpreload_eager_loading_through_polymorphic_with_more_than_one_through_record
+    Sponsor.new(:sponsor_club => clubs(:crazy_club), :sponsorable => members(:groucho)).save!
+    members = assert_queries(1) do
+      Member.all.merge!(:includes => :sponsor_club, :where => ["members.name = ?", "Groucho Marx"], :order => 'clubs.name DESC').to_a #force fallback
+    end
+    assert_equal 1, members.size
+    assert_not_nil assert_no_queries { members[0].sponsor_club }
+    assert_equal clubs(:crazy_club), members[0].sponsor_club
+  end
+
+  def test_uninitialized_has_one_through_should_return_nil_for_unsaved_record
+    assert_nil Member.new.club
+  end
+
+  def test_assigning_association_correctly_assigns_target
+    new_member = Member.create(:name => "Chris")
+    new_member.club = new_club = Club.create(:name => "LRUG")
+    assert_equal new_club, new_member.association(:club).target
+  end
+
+  def test_has_one_through_proxy_should_not_respond_to_private_methods
+    assert_raise(NoMethodError) { clubs(:moustache_club).private_method }
+    assert_raise(NoMethodError) { @member.club.private_method }
+  end
+
+  def test_has_one_through_proxy_should_respond_to_private_methods_via_send
+    clubs(:moustache_club).send(:private_method)
+    @member.club.send(:private_method)
+  end
+
+  def test_assigning_to_has_one_through_preserves_decorated_join_record
+    @organization = organizations(:nsa)
+    assert_difference 'MemberDetail.count', 1 do
+      @member_detail = MemberDetail.new(:extra_data => 'Extra')
+      @member.member_detail = @member_detail
+      @member.organization = @organization
+    end
+    assert_equal @organization, @member.organization
+    assert @organization.members.include?(@member)
+    assert_equal 'Extra', @member.member_detail.extra_data
+  end
+
+  def test_reassigning_has_one_through
+    @organization = organizations(:nsa)
+    @new_organization = organizations(:discordians)
+
+    assert_difference 'MemberDetail.count', 1 do
+      @member_detail = MemberDetail.new(:extra_data => 'Extra')
+      @member.member_detail = @member_detail
+      @member.organization = @organization
+    end
+    assert_equal @organization, @member.organization
+    assert_equal 'Extra', @member.member_detail.extra_data
+    assert @organization.members.include?(@member)
+    assert !@new_organization.members.include?(@member)
+
+    assert_no_difference 'MemberDetail.count' do
+      @member.organization = @new_organization
+    end
+    assert_equal @new_organization, @member.organization
+    assert_equal 'Extra', @member.member_detail.extra_data
+    assert !@organization.members.include?(@member)
+    assert @new_organization.members.include?(@member)
+  end
+
+  def test_preloading_has_one_through_on_belongs_to
+    MemberDetail.delete_all
+    assert_not_nil @member.member_type
+    @organization = organizations(:nsa)
+    @member_detail = MemberDetail.new
+    @member.member_detail = @member_detail
+    @member.organization = @organization
+    @member_details = assert_queries(3) do
+      MemberDetail.all.merge!(:includes => :member_type).to_a
+    end
+    @new_detail = @member_details[0]
+    assert @new_detail.send(:association, :member_type).loaded?
+    assert_no_queries { @new_detail.member_type }
+  end
+
+  def test_save_of_record_with_loaded_has_one_through
+    @club = @member.club
+    assert_not_nil @club.sponsored_member
+
+    assert_nothing_raised do
+      Club.find(@club.id).save!
+      Club.all.merge!(:includes => :sponsored_member).find(@club.id).save!
+    end
+
+    @club.sponsor.destroy
+
+    assert_nothing_raised do
+      Club.find(@club.id).save!
+      Club.all.merge!(:includes => :sponsored_member).find(@club.id).save!
+    end
+  end
+
+  def test_through_belongs_to_after_destroy
+    @member_detail = MemberDetail.new(:extra_data => 'Extra')
+    @member.member_detail = @member_detail
+    @member.save!
+
+    assert_not_nil @member_detail.member_type
+    @member_detail.destroy
+    assert_queries(1) do
+      assert_not_nil @member_detail.member_type(true)
+    end
+
+    @member_detail.member.destroy
+    assert_queries(1) do
+      assert_nil @member_detail.member_type(true)
+    end
+  end
+
+  def test_value_is_properly_quoted
+    minivan = Minivan.find('m1')
+    assert_nothing_raised do
+      minivan.dashboard
+    end
+  end
+
+  def test_has_one_through_polymorphic_with_primary_key_option
+    assert_equal categories(:general), authors(:david).essay_category
+
+    authors = Author.joins(:essay_category).where('categories.id' => categories(:general).id)
+    assert_equal authors(:david), authors.first
+
+    assert_equal owners(:blackbeard), authors(:david).essay_owner
+
+    authors = Author.joins(:essay_owner).where("owners.name = 'blackbeard'")
+    assert_equal authors(:david), authors.first
+  end
+
+  def test_has_one_through_with_primary_key_option
+    assert_equal categories(:general), authors(:david).essay_category_2
+
+    authors = Author.joins(:essay_category_2).where('categories.id' => categories(:general).id)
+    assert_equal authors(:david), authors.first
+  end
+
+  def test_has_one_through_with_default_scope_on_join_model
+    assert_equal posts(:welcome).comments.order('id').first, authors(:david).comment_on_first_post
+  end
+
+  def test_has_one_through_many_raises_exception
+    assert_raise(ActiveRecord::HasOneThroughCantAssociateThroughCollection) do
+      members(:groucho).club_through_many
+    end
+  end
+
+  def test_has_one_through_belongs_to_should_update_when_the_through_foreign_key_changes
+    minivan = minivans(:cool_first)
+
+    minivan.dashboard
+    proxy = minivan.send(:association_instance_get, :dashboard)
+
+    assert !proxy.stale_target?
+    assert_equal dashboards(:cool_first), minivan.dashboard
+
+    minivan.speedometer_id = speedometers(:second).id
+
+    assert proxy.stale_target?
+    assert_equal dashboards(:second), minivan.dashboard
+  end
+
+  def test_has_one_through_belongs_to_setting_belongs_to_foreign_key_after_nil_target_loaded
+    minivan = Minivan.new
+
+    minivan.dashboard
+    proxy = minivan.send(:association_instance_get, :dashboard)
+
+    minivan.speedometer_id = speedometers(:second).id
+
+    assert proxy.stale_target?
+    assert_equal dashboards(:second), minivan.dashboard
+  end
+
+  def test_assigning_has_one_through_belongs_to_with_new_record_owner
+    minivan   = Minivan.new
+    dashboard = dashboards(:cool_first)
+
+    minivan.dashboard = dashboard
+
+    assert_equal dashboard, minivan.dashboard
+    assert_equal dashboard, minivan.speedometer.dashboard
+  end
+
+  def test_has_one_through_with_custom_select_on_join_model_default_scope
+    assert_equal clubs(:boring_club), members(:groucho).selected_club
+  end
+
+  def test_has_one_through_relationship_cannot_have_a_counter_cache
+    assert_raise(ArgumentError) do
+      Class.new(ActiveRecord::Base) do
+        has_one :thing, through: :other_thing, counter_cache: true
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/associations/inner_join_association_test.rb b/activerecord/test/cases/associations/inner_join_association_test.rb
new file mode 100644
index 0000000000..07cf65a760
--- /dev/null
+++ b/activerecord/test/cases/associations/inner_join_association_test.rb
@@ -0,0 +1,139 @@
+require "cases/helper"
+require 'models/post'
+require 'models/comment'
+require 'models/author'
+require 'models/essay'
+require 'models/category'
+require 'models/categorization'
+require 'models/person'
+require 'models/tagging'
+require 'models/tag'
+
+class InnerJoinAssociationTest < ActiveRecord::TestCase
+  fixtures :authors, :essays, :posts, :comments, :categories, :categories_posts, :categorizations,
+           :taggings, :tags
+
+  def test_construct_finder_sql_applies_aliases_tables_on_association_conditions
+    result = Author.joins(:thinking_posts, :welcome_posts).to_a
+    assert_equal authors(:david), result.first
+  end
+
+  def test_construct_finder_sql_does_not_table_name_collide_on_duplicate_associations
+    assert_nothing_raised do
+      sql = Person.joins(:agents => {:agents => :agents}).joins(:agents => {:agents => {:primary_contact => :agents}}).to_sql
+      assert_match(/agents_people_4/i, sql)
+    end
+  end
+
+  def test_construct_finder_sql_ignores_empty_joins_hash
+    sql = Author.joins({}).to_sql
+    assert_no_match(/JOIN/i, sql)
+  end
+
+  def test_construct_finder_sql_ignores_empty_joins_array
+    sql = Author.joins([]).to_sql
+    assert_no_match(/JOIN/i, sql)
+  end
+
+  def test_join_conditions_added_to_join_clause
+    sql = Author.joins(:essays).to_sql
+    assert_match(/writer_type.*?=.*?Author/i, sql)
+    assert_no_match(/WHERE/i, sql)
+  end
+
+  def test_join_association_conditions_support_string_and_arel_expressions
+    assert_equal 0, Author.joins(:welcome_posts_with_one_comment).count
+    assert_equal 1, Author.joins(:welcome_posts_with_comments).count
+  end
+
+  def test_join_conditions_allow_nil_associations
+    authors = Author.includes(:essays).where(:essays => {:id => nil})
+    assert_equal 2, authors.count
+  end
+
+  def test_find_with_implicit_inner_joins_without_select_does_not_imply_readonly
+    authors = Author.joins(:posts)
+    assert_not authors.empty?, "expected authors to be non-empty"
+    assert authors.none? {|a| a.readonly? }, "expected no authors to be readonly"
+  end
+
+  def test_find_with_implicit_inner_joins_honors_readonly_with_select
+    authors = Author.joins(:posts).select('authors.*').to_a
+    assert !authors.empty?, "expected authors to be non-empty"
+    assert authors.all? {|a| !a.readonly? }, "expected no authors to be readonly"
+  end
+
+  def test_find_with_implicit_inner_joins_honors_readonly_false
+    authors = Author.joins(:posts).readonly(false).to_a
+    assert !authors.empty?, "expected authors to be non-empty"
+    assert authors.all? {|a| !a.readonly? }, "expected no authors to be readonly"
+  end
+
+  def test_find_with_implicit_inner_joins_does_not_set_associations
+    authors = Author.joins(:posts).select('authors.*').to_a
+    assert !authors.empty?, "expected authors to be non-empty"
+    assert authors.all? { |a| !a.instance_variable_defined?(:@posts) }, "expected no authors to have the @posts association loaded"
+  end
+
+  def test_count_honors_implicit_inner_joins
+    real_count = Author.all.to_a.sum{|a| a.posts.count }
+    assert_equal real_count, Author.joins(:posts).count, "plain inner join count should match the number of referenced posts records"
+  end
+
+  def test_calculate_honors_implicit_inner_joins
+    real_count = Author.all.to_a.sum{|a| a.posts.count }
+    assert_equal real_count, Author.joins(:posts).calculate(:count, 'authors.id'), "plain inner join count should match the number of referenced posts records"
+  end
+
+  def test_calculate_honors_implicit_inner_joins_and_distinct_and_conditions
+    real_count = Author.all.to_a.select {|a| a.posts.any? {|p| p.title =~ /^Welcome/} }.length
+    authors_with_welcoming_post_titles = Author.all.merge!(joins: :posts, where: "posts.title like 'Welcome%'").distinct.calculate(:count, 'authors.id')
+    assert_equal real_count, authors_with_welcoming_post_titles, "inner join and conditions should have only returned authors posting titles starting with 'Welcome'"
+  end
+
+  def test_find_with_sti_join
+    scope = Post.joins(:special_comments).where(:id => posts(:sti_comments).id)
+
+    # The join should match SpecialComment and its subclasses only
+    assert scope.where("comments.type" => "Comment").empty?
+    assert !scope.where("comments.type" => "SpecialComment").empty?
+    assert !scope.where("comments.type" => "SubSpecialComment").empty?
+  end
+
+  def test_find_with_conditions_on_reflection
+    assert !posts(:welcome).comments.empty?
+    assert Post.joins(:nonexistant_comments).where(:id => posts(:welcome).id).empty? # [sic!]
+  end
+
+  def test_find_with_conditions_on_through_reflection
+    assert !posts(:welcome).tags.empty?
+    assert Post.joins(:misc_tags).where(:id => posts(:welcome).id).empty?
+  end
+
+  test "the default scope of the target is applied when joining associations" do
+    author = Author.create! name: "Jon"
+    author.categorizations.create!
+    author.categorizations.create! special: true
+
+    assert_equal [author], Author.where(id: author).joins(:special_categorizations)
+  end
+
+  test "the default scope of the target is correctly aliased when joining associations" do
+    author = Author.create! name: "Jon"
+    author.categories.create! name: 'Not Special'
+    author.special_categories.create! name: 'Special'
+
+    categories = author.categories.includes(:special_categorizations).references(:special_categorizations).to_a
+    assert_equal 2, categories.size
+  end
+
+  test "the correct records are loaded when including an aliased association" do
+    author = Author.create! name: "Jon"
+    author.categories.create! name: 'Not Special'
+    author.special_categories.create! name: 'Special'
+
+    categories = author.categories.eager_load(:special_categorizations).order(:name).to_a
+    assert_equal 0, categories.first.special_categorizations.size
+    assert_equal 1, categories.second.special_categorizations.size
+  end
+end
diff --git a/activerecord/test/cases/associations/inverse_associations_test.rb b/activerecord/test/cases/associations/inverse_associations_test.rb
new file mode 100644
index 0000000000..60df4e14dd
--- /dev/null
+++ b/activerecord/test/cases/associations/inverse_associations_test.rb
@@ -0,0 +1,681 @@
+require "cases/helper"
+require 'models/man'
+require 'models/face'
+require 'models/interest'
+require 'models/zine'
+require 'models/club'
+require 'models/sponsor'
+require 'models/rating'
+require 'models/comment'
+require 'models/car'
+require 'models/bulb'
+require 'models/mixed_case_monkey'
+
+class AutomaticInverseFindingTests < ActiveRecord::TestCase
+  fixtures :ratings, :comments, :cars
+
+  def test_has_one_and_belongs_to_should_find_inverse_automatically_on_multiple_word_name
+    monkey_reflection = MixedCaseMonkey.reflect_on_association(:man)
+    man_reflection = Man.reflect_on_association(:mixed_case_monkey)
+
+    assert_respond_to monkey_reflection, :has_inverse?
+    assert monkey_reflection.has_inverse?, "The monkey reflection should have an inverse"
+    assert_equal man_reflection, monkey_reflection.inverse_of, "The monkey reflection's inverse should be the man reflection"
+
+    assert_respond_to man_reflection, :has_inverse?
+    assert man_reflection.has_inverse?, "The man reflection should have an inverse"
+    assert_equal monkey_reflection, man_reflection.inverse_of, "The man reflection's inverse should be the monkey reflection"
+  end
+
+  def test_has_one_and_belongs_to_should_find_inverse_automatically
+    car_reflection = Car.reflect_on_association(:bulb)
+    bulb_reflection = Bulb.reflect_on_association(:car)
+
+    assert_respond_to car_reflection, :has_inverse?
+    assert car_reflection.has_inverse?, "The Car reflection should have an inverse"
+    assert_equal bulb_reflection, car_reflection.inverse_of, "The Car reflection's inverse should be the Bulb reflection"
+
+    assert_respond_to bulb_reflection, :has_inverse?
+    assert bulb_reflection.has_inverse?, "The Bulb reflection should have an inverse"
+    assert_equal car_reflection, bulb_reflection.inverse_of, "The Bulb reflection's inverse should be the Car reflection"
+  end
+
+  def test_has_many_and_belongs_to_should_find_inverse_automatically
+    comment_reflection = Comment.reflect_on_association(:ratings)
+    rating_reflection = Rating.reflect_on_association(:comment)
+
+    assert_respond_to comment_reflection, :has_inverse?
+    assert comment_reflection.has_inverse?, "The Comment reflection should have an inverse"
+    assert_equal rating_reflection, comment_reflection.inverse_of, "The Comment reflection's inverse should be the Rating reflection"
+  end
+
+  def test_has_one_and_belongs_to_automatic_inverse_shares_objects
+    car = Car.first
+    bulb = Bulb.create!(car: car)
+
+    assert_equal car.bulb, bulb, "The Car's bulb should be the original bulb"
+
+    car.bulb.color = "Blue"
+    assert_equal car.bulb.color, bulb.color, "Changing the bulb's color on the car association should change the bulb's color"
+
+    bulb.color = "Red"
+    assert_equal bulb.color, car.bulb.color, "Changing the bulb's color should change the bulb's color on the car association"
+  end
+
+  def test_has_many_and_belongs_to_automatic_inverse_shares_objects_on_rating
+    comment = Comment.first
+    rating = Rating.create!(comment: comment)
+
+    assert_equal rating.comment, comment, "The Rating's comment should be the original Comment"
+
+    rating.comment.body = "Brogramming is the act of programming, like a bro."
+    assert_equal rating.comment.body, comment.body, "Changing the Comment's body on the association should change the original Comment's body"
+
+    comment.body = "Broseiden is the king of the sea of bros."
+    assert_equal comment.body, rating.comment.body, "Changing the original Comment's body should change the Comment's body on the association"
+  end
+
+  def test_has_many_and_belongs_to_automatic_inverse_shares_objects_on_comment
+    rating = Rating.create!
+    comment = Comment.first
+    rating.comment = comment
+
+    assert_equal rating.comment, comment, "The Rating's comment should be the original Comment"
+
+    rating.comment.body = "Brogramming is the act of programming, like a bro."
+    assert_equal rating.comment.body, comment.body, "Changing the Comment's body on the association should change the original Comment's body"
+
+    comment.body = "Broseiden is the king of the sea of bros."
+    assert_equal comment.body, rating.comment.body, "Changing the original Comment's body should change the Comment's body on the association"
+  end
+
+  def test_polymorphic_and_has_many_through_relationships_should_not_have_inverses
+    sponsor_reflection = Sponsor.reflect_on_association(:sponsorable)
+
+    assert_respond_to sponsor_reflection, :has_inverse?
+    assert !sponsor_reflection.has_inverse?, "A polymorphic association should not find an inverse automatically"
+
+    club_reflection = Club.reflect_on_association(:members)
+
+    assert_respond_to club_reflection, :has_inverse?
+    assert !club_reflection.has_inverse?, "A has_many_through association should not find an inverse automatically"
+  end
+
+  def test_polymorphic_relationships_should_still_not_have_inverses_when_non_polymorphic_relationship_has_the_same_name
+    man_reflection = Man.reflect_on_association(:polymorphic_face_without_inverse)
+    face_reflection = Face.reflect_on_association(:man)
+
+    assert_respond_to face_reflection, :has_inverse?
+    assert face_reflection.has_inverse?, "For this test, the non-polymorphic association must have an inverse"
+
+    assert_respond_to man_reflection, :has_inverse?
+    assert !man_reflection.has_inverse?, "The target of a polymorphic association should not find an inverse automatically"
+  end
+end
+
+class InverseAssociationTests < ActiveRecord::TestCase
+  def test_should_allow_for_inverse_of_options_in_associations
+    assert_nothing_raised(ArgumentError, 'ActiveRecord should allow the inverse_of options on has_many') do
+      Class.new(ActiveRecord::Base).has_many(:wheels, :inverse_of => :car)
+    end
+
+    assert_nothing_raised(ArgumentError, 'ActiveRecord should allow the inverse_of options on has_one') do
+      Class.new(ActiveRecord::Base).has_one(:engine, :inverse_of => :car)
+    end
+
+    assert_nothing_raised(ArgumentError, 'ActiveRecord should allow the inverse_of options on belongs_to') do
+      Class.new(ActiveRecord::Base).belongs_to(:car, :inverse_of => :driver)
+    end
+  end
+
+  def test_should_be_able_to_ask_a_reflection_if_it_has_an_inverse
+    has_one_with_inverse_ref = Man.reflect_on_association(:face)
+    assert_respond_to has_one_with_inverse_ref, :has_inverse?
+    assert has_one_with_inverse_ref.has_inverse?
+
+    has_many_with_inverse_ref = Man.reflect_on_association(:interests)
+    assert_respond_to has_many_with_inverse_ref, :has_inverse?
+    assert has_many_with_inverse_ref.has_inverse?
+
+    belongs_to_with_inverse_ref = Face.reflect_on_association(:man)
+    assert_respond_to belongs_to_with_inverse_ref, :has_inverse?
+    assert belongs_to_with_inverse_ref.has_inverse?
+
+    has_one_without_inverse_ref = Club.reflect_on_association(:sponsor)
+    assert_respond_to has_one_without_inverse_ref, :has_inverse?
+    assert !has_one_without_inverse_ref.has_inverse?
+
+    has_many_without_inverse_ref = Club.reflect_on_association(:memberships)
+    assert_respond_to has_many_without_inverse_ref, :has_inverse?
+    assert !has_many_without_inverse_ref.has_inverse?
+
+    belongs_to_without_inverse_ref = Sponsor.reflect_on_association(:sponsor_club)
+    assert_respond_to belongs_to_without_inverse_ref, :has_inverse?
+    assert !belongs_to_without_inverse_ref.has_inverse?
+  end
+
+  def test_should_be_able_to_ask_a_reflection_what_it_is_the_inverse_of
+    has_one_ref = Man.reflect_on_association(:face)
+    assert_respond_to has_one_ref, :inverse_of
+
+    has_many_ref = Man.reflect_on_association(:interests)
+    assert_respond_to has_many_ref, :inverse_of
+
+    belongs_to_ref = Face.reflect_on_association(:man)
+    assert_respond_to belongs_to_ref, :inverse_of
+  end
+
+  def test_inverse_of_method_should_supply_the_actual_reflection_instance_it_is_the_inverse_of
+    has_one_ref = Man.reflect_on_association(:face)
+    assert_equal Face.reflect_on_association(:man), has_one_ref.inverse_of
+
+    has_many_ref = Man.reflect_on_association(:interests)
+    assert_equal Interest.reflect_on_association(:man), has_many_ref.inverse_of
+
+    belongs_to_ref = Face.reflect_on_association(:man)
+    assert_equal Man.reflect_on_association(:face), belongs_to_ref.inverse_of
+  end
+
+  def test_associations_with_no_inverse_of_should_return_nil
+    has_one_ref = Club.reflect_on_association(:sponsor)
+    assert_nil has_one_ref.inverse_of
+
+    has_many_ref = Club.reflect_on_association(:memberships)
+    assert_nil has_many_ref.inverse_of
+
+    belongs_to_ref = Sponsor.reflect_on_association(:sponsor_club)
+    assert_nil belongs_to_ref.inverse_of
+  end
+end
+
+class InverseHasOneTests < ActiveRecord::TestCase
+  fixtures :men, :faces
+
+  def test_parent_instance_should_be_shared_with_child_on_find
+    m = men(:gordon)
+    f = m.face
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = 'Mungo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to child-owned instance"
+  end
+
+
+  def test_parent_instance_should_be_shared_with_eager_loaded_child_on_find
+    m = Man.all.merge!(:where => {:name => 'Gordon'}, :includes => :face).first
+    f = m.face
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = 'Mungo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to child-owned instance"
+
+    m = Man.all.merge!(:where => {:name => 'Gordon'}, :includes => :face, :order => 'faces.id').first
+    f = m.face
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = 'Mungo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_built_child
+    m = Man.first
+    f = m.build_face(:description => 'haunted')
+    assert_not_nil f.man
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = 'Mungo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to just-built-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_created_child
+    m = Man.first
+    f = m.create_face(:description => 'haunted')
+    assert_not_nil f.man
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = 'Mungo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_created_child_via_bang_method
+    m = Man.first
+    f = m.create_face!(:description => 'haunted')
+    assert_not_nil f.man
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = 'Mungo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_replaced_via_accessor_child
+    m = Man.first
+    f = Face.new(:description => 'haunted')
+    m.face = f
+    assert_not_nil f.man
+    assert_equal m.name, f.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to parent instance"
+    f.man.name = 'Mungo'
+    assert_equal m.name, f.man.name, "Name of man should be the same after changes to replaced-child-owned instance"
+  end
+
+  def test_trying_to_use_inverses_that_dont_exist_should_raise_an_error
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Man.first.dirty_face }
+  end
+end
+
+class InverseHasManyTests < ActiveRecord::TestCase
+  fixtures :men, :interests
+
+  def test_parent_instance_should_be_shared_with_every_child_on_find
+    m = men(:gordon)
+    is = m.interests
+    is.each do |i|
+      assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+      m.name = 'Bongo'
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+      i.man.name = 'Mungo'
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to child-owned instance"
+    end
+  end
+
+  def test_parent_instance_should_be_shared_with_eager_loaded_children
+    m = Man.all.merge!(:where => {:name => 'Gordon'}, :includes => :interests).first
+    is = m.interests
+    is.each do |i|
+      assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+      m.name = 'Bongo'
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+      i.man.name = 'Mungo'
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to child-owned instance"
+    end
+
+    m = Man.all.merge!(:where => {:name => 'Gordon'}, :includes => :interests, :order => 'interests.id').first
+    is = m.interests
+    is.each do |i|
+      assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+      m.name = 'Bongo'
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+      i.man.name = 'Mungo'
+      assert_equal m.name, i.man.name, "Name of man should be the same after changes to child-owned instance"
+    end
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_block_style_built_child
+    m = Man.first
+    i = m.interests.build {|ii| ii.topic = 'Industrial Revolution Re-enactment'}
+    assert_not_nil i.topic, "Child attributes supplied to build via blocks should be populated"
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = 'Mungo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to just-built-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_created_via_bang_method_child
+    m = Man.first
+    i = m.interests.create!(:topic => 'Industrial Revolution Re-enactment')
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = 'Mungo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_newly_block_style_created_child
+    m = Man.first
+    i = m.interests.create {|ii| ii.topic = 'Industrial Revolution Re-enactment'}
+    assert_not_nil i.topic, "Child attributes supplied to create via blocks should be populated"
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = 'Mungo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_within_create_block_of_new_child
+    man = Man.first
+    interest = man.interests.create do |i|
+      assert i.man.equal?(man), "Man of child should be the same instance as a parent"
+    end
+    assert interest.man.equal?(man), "Man of the child should still be the same instance as a parent"
+  end
+
+  def test_parent_instance_should_be_shared_within_build_block_of_new_child
+    man = Man.first
+    interest = man.interests.build do |i|
+      assert i.man.equal?(man), "Man of child should be the same instance as a parent"
+    end
+    assert interest.man.equal?(man), "Man of the child should still be the same instance as a parent"
+  end
+
+  def test_parent_instance_should_be_shared_with_poked_in_child
+    m = men(:gordon)
+    i = Interest.create(:topic => 'Industrial Revolution Re-enactment')
+    m.interests << i
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = 'Mungo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to newly-created-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_replaced_via_accessor_children
+    m = Man.first
+    i = Interest.new(:topic => 'Industrial Revolution Re-enactment')
+    m.interests = [i]
+    assert_not_nil i.man
+    assert_equal m.name, i.man.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to parent instance"
+    i.man.name = 'Mungo'
+    assert_equal m.name, i.man.name, "Name of man should be the same after changes to replaced-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_first_and_last_child
+    man = Man.first
+
+    assert man.interests.first.man.equal? man
+    assert man.interests.last.man.equal? man
+  end
+
+  def test_parent_instance_should_be_shared_with_first_n_and_last_n_children
+    man = Man.first
+
+    interests = man.interests.first(2)
+    assert interests[0].man.equal? man
+    assert interests[1].man.equal? man
+
+    interests = man.interests.last(2)
+    assert interests[0].man.equal? man
+    assert interests[1].man.equal? man
+  end
+
+  def test_parent_instance_should_find_child_instance_using_child_instance_id
+    man = Man.create!
+    interest = Interest.create!
+    man.interests = [interest]
+
+    assert interest.equal?(man.interests.first), "The inverse association should use the interest already created and held in memory"
+    assert interest.equal?(man.interests.find(interest.id)), "The inverse association should use the interest already created and held in memory"
+    assert man.equal?(man.interests.first.man), "Two inversion should lead back to the same object that was originally held"
+    assert man.equal?(man.interests.find(interest.id).man), "Two inversions should lead back to the same object that was originally held"
+  end
+
+  def test_parent_instance_should_find_child_instance_using_child_instance_id_when_created
+    man = Man.create!
+    interest = Interest.create!(man: man)
+
+    assert man.equal?(man.interests.first.man), "Two inverses should lead back to the same object that was originally held"
+    assert man.equal?(man.interests.find(interest.id).man), "Two inversions should lead back to the same object that was originally held"
+
+    assert_equal man.name, man.interests.find(interest.id).man.name, "The name of the man should match before the name is changed"
+    man.name = "Ben Bitdiddle"
+    assert_equal man.name, man.interests.find(interest.id).man.name, "The name of the man should match after the parent name is changed"
+    man.interests.find(interest.id).man.name = "Alyssa P. Hacker"
+    assert_equal man.name, man.interests.find(interest.id).man.name, "The name of the man should match after the child name is changed"
+  end
+
+  def test_find_on_child_instance_with_id_should_not_load_all_child_records
+    man = Man.create!
+    interest = Interest.create!(man: man)
+
+    man.interests.find(interest.id)
+    assert_not man.interests.loaded?
+  end
+
+  def test_raise_record_not_found_error_when_invalid_ids_are_passed
+    # delete all interest records to ensure that hard coded invalid_id(s)
+    # are indeed invalid.
+    Interest.delete_all
+
+    man = Man.create!
+
+    invalid_id = 245324523
+    assert_raise(ActiveRecord::RecordNotFound) { man.interests.find(invalid_id) }
+
+    invalid_ids = [8432342, 2390102913, 2453245234523452]
+    assert_raise(ActiveRecord::RecordNotFound) { man.interests.find(invalid_ids) }
+  end
+
+  def test_raise_record_not_found_error_when_no_ids_are_passed
+    man = Man.create!
+
+    assert_raise(ActiveRecord::RecordNotFound) { man.interests.find() }
+  end
+
+  def test_trying_to_use_inverses_that_dont_exist_should_raise_an_error
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Man.first.secret_interests }
+  end
+
+  def test_child_instance_should_point_to_parent_without_saving
+    man = Man.new
+    i = Interest.create(:topic => 'Industrial Revolution Re-enactment')
+
+    man.interests << i
+    assert_not_nil i.man
+
+    i.man.name = "Charles"
+    assert_equal i.man.name, man.name
+
+    assert !man.persisted?
+  end
+end
+
+class InverseBelongsToTests < ActiveRecord::TestCase
+  fixtures :men, :faces, :interests
+
+  def test_child_instance_should_be_shared_with_parent_on_find
+    f = faces(:trusting)
+    m = f.man
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = 'pleasing'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to parent-owned instance"
+  end
+
+  def test_eager_loaded_child_instance_should_be_shared_with_parent_on_find
+    f = Face.all.merge!(:includes => :man, :where => {:description => 'trusting'}).first
+    m = f.man
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = 'pleasing'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to parent-owned instance"
+
+    f = Face.all.merge!(:includes => :man, :order => 'men.id', :where => {:description => 'trusting'}).first
+    m = f.man
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = 'pleasing'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_newly_built_parent
+    f = faces(:trusting)
+    m = f.build_man(:name => 'Charles')
+    assert_not_nil m.face
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = 'pleasing'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to just-built-parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_newly_created_parent
+    f = faces(:trusting)
+    m = f.create_man(:name => 'Charles')
+    assert_not_nil m.face
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = 'pleasing'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to newly-created-parent-owned instance"
+  end
+
+  def test_should_not_try_to_set_inverse_instances_when_the_inverse_is_a_has_many
+    i = interests(:trainspotting)
+    m = i.man
+    assert_not_nil m.interests
+    iz = m.interests.detect { |_iz| _iz.id == i.id}
+    assert_not_nil iz
+    assert_equal i.topic, iz.topic, "Interest topics should be the same before changes to child"
+    i.topic = 'Eating cheese with a spoon'
+    assert_not_equal i.topic, iz.topic, "Interest topics should not be the same after changes to child"
+    iz.topic = 'Cow tipping'
+    assert_not_equal i.topic, iz.topic, "Interest topics should not be the same after changes to parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_replaced_via_accessor_parent
+    f = Face.first
+    m = Man.new(:name => 'Charles')
+    f.man = m
+    assert_not_nil m.face
+    assert_equal f.description, m.face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to child instance"
+    m.face.description = 'pleasing'
+    assert_equal f.description, m.face.description, "Description of face should be the same after changes to replaced-parent-owned instance"
+  end
+
+  def test_trying_to_use_inverses_that_dont_exist_should_raise_an_error
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.horrible_man }
+  end
+end
+
+class InversePolymorphicBelongsToTests < ActiveRecord::TestCase
+  fixtures :men, :faces, :interests
+
+  def test_child_instance_should_be_shared_with_parent_on_find
+    f = Face.all.merge!(:where => {:description => 'confused'}).first
+    m = f.polymorphic_man
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to child instance"
+    m.polymorphic_face.description = 'pleasing'
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to parent-owned instance"
+  end
+
+  def test_eager_loaded_child_instance_should_be_shared_with_parent_on_find
+    f = Face.all.merge!(:where => {:description => 'confused'}, :includes => :man).first
+    m = f.polymorphic_man
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to child instance"
+    m.polymorphic_face.description = 'pleasing'
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to parent-owned instance"
+
+    f = Face.all.merge!(:where => {:description => 'confused'}, :includes => :man, :order => 'men.id').first
+    m = f.polymorphic_man
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same before changes to child instance"
+    f.description = 'gormless'
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to child instance"
+    m.polymorphic_face.description = 'pleasing'
+    assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_replaced_via_accessor_parent
+    face = faces(:confused)
+    new_man = Man.new
+
+    assert_not_nil face.polymorphic_man
+    face.polymorphic_man = new_man
+
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same before changes to parent instance"
+    face.description = 'Bongo'
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to parent instance"
+    new_man.polymorphic_face.description = 'Mungo'
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to replaced-parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_replaced_via_method_parent
+    face = faces(:confused)
+    new_man = Man.new
+
+    assert_not_nil face.polymorphic_man
+    face.polymorphic_man = new_man
+
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same before changes to parent instance"
+    face.description = 'Bongo'
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to parent instance"
+    new_man.polymorphic_face.description = 'Mungo'
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to replaced-parent-owned instance"
+  end
+
+  def test_inversed_instance_should_not_be_reloaded_after_stale_state_changed
+    new_man = Man.new
+    face = Face.new
+    new_man.face = face
+
+    old_inversed_man = face.man
+    new_man.save!
+    new_inversed_man = face.man
+
+    assert_equal old_inversed_man.object_id, new_inversed_man.object_id
+  end
+
+  def test_should_not_try_to_set_inverse_instances_when_the_inverse_is_a_has_many
+    i = interests(:llama_wrangling)
+    m = i.polymorphic_man
+    assert_not_nil m.polymorphic_interests
+    iz = m.polymorphic_interests.detect { |_iz| _iz.id == i.id}
+    assert_not_nil iz
+    assert_equal i.topic, iz.topic, "Interest topics should be the same before changes to child"
+    i.topic = 'Eating cheese with a spoon'
+    assert_not_equal i.topic, iz.topic, "Interest topics should not be the same after changes to child"
+    iz.topic = 'Cow tipping'
+    assert_not_equal i.topic, iz.topic, "Interest topics should not be the same after changes to parent-owned instance"
+  end
+
+  def test_trying_to_access_inverses_that_dont_exist_shouldnt_raise_an_error
+    # Ideally this would, if only for symmetry's sake with other association types
+    assert_nothing_raised(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.horrible_polymorphic_man }
+  end
+
+  def test_trying_to_set_polymorphic_inverses_that_dont_exist_at_all_should_raise_an_error
+    # fails because no class has the correct inverse_of for horrible_polymorphic_man
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.horrible_polymorphic_man = Man.first }
+  end
+
+  def test_trying_to_set_polymorphic_inverses_that_dont_exist_on_the_instance_being_set_should_raise_an_error
+    # passes because Man does have the correct inverse_of
+    assert_nothing_raised(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.polymorphic_man = Man.first }
+    # fails because Interest does have the correct inverse_of
+    assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.polymorphic_man = Interest.first }
+  end
+end
+
+# NOTE - these tests might not be meaningful, ripped as they were from the parental_control plugin
+# which would guess the inverse rather than look for an explicit configuration option.
+class InverseMultipleHasManyInversesForSameModel < ActiveRecord::TestCase
+  fixtures :men, :interests, :zines
+
+  def test_that_we_can_load_associations_that_have_the_same_reciprocal_name_from_different_models
+    assert_nothing_raised(ActiveRecord::AssociationTypeMismatch) do
+      i = Interest.first
+      i.zine
+      i.man
+    end
+  end
+
+  def test_that_we_can_create_associations_that_have_the_same_reciprocal_name_from_different_models
+    assert_nothing_raised(ActiveRecord::AssociationTypeMismatch) do
+      i = Interest.first
+      i.build_zine(:title => 'Get Some in Winter! 2008')
+      i.build_man(:name => 'Gordon')
+      i.save!
+    end
+  end
+end
diff --git a/activerecord/test/cases/associations/join_model_test.rb b/activerecord/test/cases/associations/join_model_test.rb
new file mode 100644
index 0000000000..cace7ba142
--- /dev/null
+++ b/activerecord/test/cases/associations/join_model_test.rb
@@ -0,0 +1,751 @@
+require "cases/helper"
+require 'models/tag'
+require 'models/tagging'
+require 'models/post'
+require 'models/rating'
+require 'models/item'
+require 'models/comment'
+require 'models/author'
+require 'models/category'
+require 'models/categorization'
+require 'models/vertex'
+require 'models/edge'
+require 'models/book'
+require 'models/citation'
+require 'models/aircraft'
+require 'models/engine'
+require 'models/car'
+
+class AssociationsJoinModelTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  fixtures :posts, :authors, :categories, :categorizations, :comments, :tags, :taggings, :author_favorites, :vertices, :items, :books,
+    # Reload edges table from fixtures as otherwise repeated test was failing
+    :edges
+
+  def test_has_many
+    assert authors(:david).categories.include?(categories(:general))
+  end
+
+  def test_has_many_inherited
+    assert authors(:mary).categories.include?(categories(:sti_test))
+  end
+
+  def test_inherited_has_many
+    assert categories(:sti_test).authors.include?(authors(:mary))
+  end
+
+  def test_has_many_uniq_through_join_model
+    assert_equal 2, authors(:mary).categorized_posts.size
+    assert_equal 1, authors(:mary).unique_categorized_posts.size
+  end
+
+  def test_has_many_uniq_through_count
+    author = authors(:mary)
+    assert !authors(:mary).unique_categorized_posts.loaded?
+    assert_queries(1) { assert_equal 1, author.unique_categorized_posts.count }
+    assert_queries(1) { assert_equal 1, author.unique_categorized_posts.count(:title) }
+    assert_queries(1) { assert_equal 0, author.unique_categorized_posts.where(title: nil).count(:title) }
+    assert !authors(:mary).unique_categorized_posts.loaded?
+  end
+
+  def test_has_many_uniq_through_find
+    assert_equal 1, authors(:mary).unique_categorized_posts.to_a.size
+  end
+
+  def test_polymorphic_has_many_going_through_join_model
+    assert_equal tags(:general), tag = posts(:welcome).tags.first
+    assert_no_queries do
+      tag.tagging
+    end
+  end
+
+  def test_count_polymorphic_has_many
+    assert_equal 1, posts(:welcome).taggings.count
+    assert_equal 1, posts(:welcome).tags.count
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_find
+    assert_equal tags(:general), tag = posts(:welcome).tags.first
+    assert_no_queries do
+      tag.tagging
+    end
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_include_on_source_reflection
+    assert_equal tags(:general), tag = posts(:welcome).funky_tags.first
+    assert_no_queries do
+      tag.tagging
+    end
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_include_on_source_reflection_with_find
+    assert_equal tags(:general), tag = posts(:welcome).funky_tags.first
+    assert_no_queries do
+      tag.tagging
+    end
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_custom_select_and_joins
+    assert_equal tags(:general), tag = posts(:welcome).tags.add_joins_and_select.first
+    assert_nothing_raised(NoMethodError) { tag.author_id }
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_custom_foreign_key
+    assert_equal tags(:misc), taggings(:welcome_general).super_tag
+    assert_equal tags(:misc), posts(:welcome).super_tags.first
+  end
+
+  def test_polymorphic_has_many_create_model_with_inheritance_and_custom_base_class
+    post = SubStiPost.create :title => 'SubStiPost', :body => 'SubStiPost body'
+    assert_instance_of SubStiPost, post
+
+    tagging = tags(:misc).taggings.create(:taggable => post)
+    assert_equal "SubStiPost", tagging.taggable_type
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_inheritance
+    assert_equal tags(:general), posts(:thinking).tags.first
+  end
+
+  def test_polymorphic_has_many_going_through_join_model_with_inheritance_with_custom_class_name
+    assert_equal tags(:general), posts(:thinking).funky_tags.first
+  end
+
+  def test_polymorphic_has_many_create_model_with_inheritance
+    post = posts(:thinking)
+    assert_instance_of SpecialPost, post
+
+    tagging = tags(:misc).taggings.create(:taggable => post)
+    assert_equal "Post", tagging.taggable_type
+  end
+
+  def test_polymorphic_has_one_create_model_with_inheritance
+    tagging = tags(:misc).create_tagging(:taggable => posts(:thinking))
+    assert_equal "Post", tagging.taggable_type
+  end
+
+  def test_set_polymorphic_has_many
+    tagging = tags(:misc).taggings.create
+    posts(:thinking).taggings << tagging
+    assert_equal "Post", tagging.taggable_type
+  end
+
+  def test_set_polymorphic_has_one
+    tagging = tags(:misc).taggings.create
+    posts(:thinking).tagging = tagging
+
+    assert_equal "Post",              tagging.taggable_type
+    assert_equal posts(:thinking).id, tagging.taggable_id
+    assert_equal posts(:thinking),    tagging.taggable
+  end
+
+  def test_set_polymorphic_has_one_on_new_record
+    tagging = tags(:misc).taggings.create
+    post = Post.new :title => "foo", :body => "bar"
+    post.tagging = tagging
+    post.save!
+
+    assert_equal "Post",  tagging.taggable_type
+    assert_equal post.id, tagging.taggable_id
+    assert_equal post,    tagging.taggable
+  end
+
+  def test_create_polymorphic_has_many_with_scope
+    old_count = posts(:welcome).taggings.count
+    tagging = posts(:welcome).taggings.create(:tag => tags(:misc))
+    assert_equal "Post", tagging.taggable_type
+    assert_equal old_count+1, posts(:welcome).taggings.count
+  end
+
+  def test_create_bang_polymorphic_with_has_many_scope
+    old_count = posts(:welcome).taggings.count
+    tagging = posts(:welcome).taggings.create!(:tag => tags(:misc))
+    assert_equal "Post", tagging.taggable_type
+    assert_equal old_count+1, posts(:welcome).taggings.count
+  end
+
+  def test_create_polymorphic_has_one_with_scope
+    old_count = Tagging.count
+    tagging = posts(:welcome).create_tagging(:tag => tags(:misc))
+    assert_equal "Post", tagging.taggable_type
+    assert_equal old_count+1, Tagging.count
+  end
+
+  def test_delete_polymorphic_has_many_with_delete_all
+    assert_equal 1, posts(:welcome).taggings.count
+    posts(:welcome).taggings.first.update_columns taggable_type: 'PostWithHasManyDeleteAll'
+    post = find_post_with_dependency(1, :has_many, :taggings, :delete_all)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count-1, Tagging.count
+    assert_equal 0, posts(:welcome).taggings.count
+  end
+
+  def test_delete_polymorphic_has_many_with_destroy
+    assert_equal 1, posts(:welcome).taggings.count
+    posts(:welcome).taggings.first.update_columns taggable_type: 'PostWithHasManyDestroy'
+    post = find_post_with_dependency(1, :has_many, :taggings, :destroy)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count-1, Tagging.count
+    assert_equal 0, posts(:welcome).taggings.count
+  end
+
+  def test_delete_polymorphic_has_many_with_nullify
+    assert_equal 1, posts(:welcome).taggings.count
+    posts(:welcome).taggings.first.update_columns taggable_type: 'PostWithHasManyNullify'
+    post = find_post_with_dependency(1, :has_many, :taggings, :nullify)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count, Tagging.count
+    assert_equal 0, posts(:welcome).taggings.count
+  end
+
+  def test_delete_polymorphic_has_one_with_destroy
+    assert posts(:welcome).tagging
+    posts(:welcome).tagging.update_columns taggable_type: 'PostWithHasOneDestroy'
+    post = find_post_with_dependency(1, :has_one, :tagging, :destroy)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count-1, Tagging.count
+    assert_nil posts(:welcome).tagging(true)
+  end
+
+  def test_delete_polymorphic_has_one_with_nullify
+    assert posts(:welcome).tagging
+    posts(:welcome).tagging.update_columns taggable_type: 'PostWithHasOneNullify'
+    post = find_post_with_dependency(1, :has_one, :tagging, :nullify)
+
+    old_count = Tagging.count
+    post.destroy
+    assert_equal old_count, Tagging.count
+    assert_nil posts(:welcome).tagging(true)
+  end
+
+  def test_has_many_with_piggyback
+    assert_equal "2", categories(:sti_test).authors_with_select.first.post_id.to_s
+  end
+
+  def test_create_through_has_many_with_piggyback
+    category = categories(:sti_test)
+    ernie = category.authors_with_select.create(:name => 'Ernie')
+    assert_nothing_raised do
+      assert_equal ernie, category.authors_with_select.detect {|a| a.name == 'Ernie'}
+    end
+  end
+
+  def test_include_has_many_through
+    posts              = Post.all.merge!(:order => 'posts.id').to_a
+    posts_with_authors = Post.all.merge!(:includes => :authors, :order => 'posts.id').to_a
+    assert_equal posts.length, posts_with_authors.length
+    posts.length.times do |i|
+      assert_equal posts[i].authors.length, assert_no_queries { posts_with_authors[i].authors.length }
+    end
+  end
+
+  def test_include_polymorphic_has_one
+    post    = Post.includes(:tagging).find posts(:welcome).id
+    tagging = taggings(:welcome_general)
+    assert_no_queries do
+      assert_equal tagging, post.tagging
+    end
+  end
+
+  def test_include_polymorphic_has_one_defined_in_abstract_parent
+    item    = Item.includes(:tagging).find items(:dvd).id
+    tagging = taggings(:godfather)
+    assert_no_queries do
+      assert_equal tagging, item.tagging
+    end
+  end
+
+  def test_include_polymorphic_has_many_through
+    posts           = Post.all.merge!(:order => 'posts.id').to_a
+    posts_with_tags = Post.all.merge!(:includes => :tags, :order => 'posts.id').to_a
+    assert_equal posts.length, posts_with_tags.length
+    posts.length.times do |i|
+      assert_equal posts[i].tags.length, assert_no_queries { posts_with_tags[i].tags.length }
+    end
+  end
+
+  def test_include_polymorphic_has_many
+    posts               = Post.all.merge!(:order => 'posts.id').to_a
+    posts_with_taggings = Post.all.merge!(:includes => :taggings, :order => 'posts.id').to_a
+    assert_equal posts.length, posts_with_taggings.length
+    posts.length.times do |i|
+      assert_equal posts[i].taggings.length, assert_no_queries { posts_with_taggings[i].taggings.length }
+    end
+  end
+
+  def test_has_many_find_all
+    assert_equal [categories(:general)], authors(:david).categories.to_a
+  end
+
+  def test_has_many_find_first
+    assert_equal categories(:general), authors(:david).categories.first
+  end
+
+  def test_has_many_with_hash_conditions
+    assert_equal categories(:general), authors(:david).categories_like_general.first
+  end
+
+  def test_has_many_find_conditions
+    assert_equal categories(:general), authors(:david).categories.where("categories.name = 'General'").first
+    assert_nil authors(:david).categories.where("categories.name = 'Technology'").first
+  end
+
+  def test_has_many_array_methods_called_by_method_missing
+    assert authors(:david).categories.any? { |category| category.name == 'General' }
+    assert_nothing_raised { authors(:david).categories.sort }
+  end
+
+  def test_has_many_going_through_join_model_with_custom_foreign_key
+    assert_equal [authors(:bob)], posts(:thinking).authors
+    assert_equal [authors(:mary)], posts(:authorless).authors
+  end
+
+  def test_has_many_going_through_join_model_with_custom_primary_key
+    assert_equal [authors(:david)], posts(:thinking).authors_using_author_id
+  end
+
+  def test_has_many_going_through_polymorphic_join_model_with_custom_primary_key
+    assert_equal [tags(:general)], posts(:eager_other).tags_using_author_id
+  end
+
+  def test_has_many_through_with_custom_primary_key_on_belongs_to_source
+    assert_equal [authors(:david), authors(:david)], posts(:thinking).author_using_custom_pk
+  end
+
+  def test_has_many_through_with_custom_primary_key_on_has_many_source
+    assert_equal [authors(:david), authors(:bob)], posts(:thinking).authors_using_custom_pk.order('authors.id')
+  end
+
+  def test_belongs_to_polymorphic_with_counter_cache
+    assert_equal 1, posts(:welcome)[:tags_count]
+    tagging = posts(:welcome).taggings.create(:tag => tags(:general))
+    assert_equal 2, posts(:welcome, :reload)[:tags_count]
+    tagging.destroy
+    assert_equal 1, posts(:welcome, :reload)[:tags_count]
+  end
+
+  def test_unavailable_through_reflection
+    assert_raise(ActiveRecord::HasManyThroughAssociationNotFoundError) { authors(:david).nothings }
+  end
+
+  def test_has_many_through_join_model_with_conditions
+    assert_equal [], posts(:welcome).invalid_taggings
+    assert_equal [], posts(:welcome).invalid_tags
+  end
+
+  def test_has_many_polymorphic
+    assert_raise ActiveRecord::HasManyThroughAssociationPolymorphicSourceError do
+      tags(:general).taggables
+    end
+
+    assert_raise ActiveRecord::HasManyThroughAssociationPolymorphicThroughError do
+      taggings(:welcome_general).things
+    end
+
+    assert_raise ActiveRecord::EagerLoadPolymorphicError do
+      tags(:general).taggings.includes(:taggable).where('bogus_table.column = 1').references(:bogus_table).to_a
+    end
+  end
+
+  def test_has_many_polymorphic_with_source_type
+    # added sort by ID as otherwise Oracle select sometimes returned rows in different order
+    assert_equal posts(:welcome, :thinking).sort_by(&:id), tags(:general).tagged_posts.sort_by(&:id)
+  end
+
+  def test_eager_has_many_polymorphic_with_source_type
+    tag_with_include = Tag.all.merge!(:includes => :tagged_posts).find(tags(:general).id)
+    desired = posts(:welcome, :thinking)
+    assert_no_queries do
+      # added sort by ID as otherwise test using JRuby was failing as array elements were in different order
+      assert_equal desired.sort_by(&:id), tag_with_include.tagged_posts.sort_by(&:id)
+    end
+    assert_equal 5, tag_with_include.taggings.length
+  end
+
+  def test_has_many_through_has_many_find_all
+    assert_equal comments(:greetings), authors(:david).comments.order('comments.id').to_a.first
+  end
+
+  def test_has_many_through_has_many_find_all_with_custom_class
+    assert_equal comments(:greetings), authors(:david).funky_comments.order('comments.id').to_a.first
+  end
+
+  def test_has_many_through_has_many_find_first
+    assert_equal comments(:greetings), authors(:david).comments.order('comments.id').first
+  end
+
+  def test_has_many_through_has_many_find_conditions
+    options = { :where => "comments.#{QUOTED_TYPE}='SpecialComment'", :order => 'comments.id' }
+    assert_equal comments(:does_it_hurt), authors(:david).comments.merge(options).first
+  end
+
+  def test_has_many_through_has_many_find_by_id
+    assert_equal comments(:more_greetings), authors(:david).comments.find(2)
+  end
+
+  def test_has_many_through_polymorphic_has_one
+    assert_equal Tagging.find(1,2).sort_by { |t| t.id }, authors(:david).taggings_2
+  end
+
+  def test_has_many_through_polymorphic_has_many
+    assert_equal taggings(:welcome_general, :thinking_general), authors(:david).taggings.distinct.sort_by { |t| t.id }
+  end
+
+  def test_include_has_many_through_polymorphic_has_many
+    author            = Author.includes(:taggings).find authors(:david).id
+    expected_taggings = taggings(:welcome_general, :thinking_general)
+    assert_no_queries do
+      assert_equal expected_taggings, author.taggings.distinct.sort_by { |t| t.id }
+    end
+  end
+
+  def test_eager_load_has_many_through_has_many
+    author = Author.all.merge!(:where => ['name = ?', 'David'], :includes => :comments, :order => 'comments.id').first
+    SpecialComment.new; VerySpecialComment.new
+    assert_no_queries do
+      assert_equal [1,2,3,5,6,7,8,9,10,12], author.comments.collect(&:id)
+    end
+  end
+
+  def test_eager_load_has_many_through_has_many_with_conditions
+    post = Post.all.merge!(:includes => :invalid_tags).first
+    assert_no_queries do
+      post.invalid_tags
+    end
+  end
+
+  def test_eager_belongs_to_and_has_one_not_singularized
+    assert_nothing_raised do
+      Author.all.merge!(:includes => :author_address).first
+      AuthorAddress.all.merge!(:includes => :author).first
+    end
+  end
+
+  def test_self_referential_has_many_through
+    assert_equal [authors(:mary)], authors(:david).favorite_authors
+    assert_equal [],               authors(:mary).favorite_authors
+  end
+
+  def test_add_to_self_referential_has_many_through
+    new_author = Author.create(:name => "Bob")
+    authors(:david).author_favorites.create :favorite_author => new_author
+    assert_equal new_author, authors(:david).reload.favorite_authors.first
+  end
+
+  def test_has_many_through_uses_conditions_specified_on_the_has_many_association
+    author = Author.first
+    assert author.comments.present?
+    assert author.nonexistant_comments.blank?
+  end
+
+  def test_has_many_through_uses_correct_attributes
+    assert_nil posts(:thinking).tags.find_by_name("General").attributes["tag_id"]
+  end
+
+  def test_associating_unsaved_records_with_has_many_through
+    saved_post = posts(:thinking)
+    new_tag = Tag.new(:name => "new")
+
+    saved_post.tags << new_tag
+    assert new_tag.persisted? #consistent with habtm!
+    assert saved_post.persisted?
+    assert saved_post.tags.include?(new_tag)
+
+    assert new_tag.persisted?
+    assert saved_post.reload.tags(true).include?(new_tag)
+
+
+    new_post = Post.new(:title => "Association replacement works!", :body => "You best believe it.")
+    saved_tag = tags(:general)
+
+    new_post.tags << saved_tag
+    assert !new_post.persisted?
+    assert saved_tag.persisted?
+    assert new_post.tags.include?(saved_tag)
+
+    new_post.save!
+    assert new_post.persisted?
+    assert new_post.reload.tags(true).include?(saved_tag)
+
+    assert !posts(:thinking).tags.build.persisted?
+    assert !posts(:thinking).tags.new.persisted?
+  end
+
+  def test_create_associate_when_adding_to_has_many_through
+    count = posts(:thinking).tags.count
+    push = Tag.create!(:name => 'pushme')
+    post_thinking = posts(:thinking)
+    assert_nothing_raised { post_thinking.tags << push }
+    assert_nil( wrong = post_thinking.tags.detect { |t| t.class != Tag },
+                message = "Expected a Tag in tags collection, got #{wrong.class}.")
+    assert_nil( wrong = post_thinking.taggings.detect { |t| t.class != Tagging },
+                message = "Expected a Tagging in taggings collection, got #{wrong.class}.")
+    assert_equal(count + 1, post_thinking.reload.tags.size)
+    assert_equal(count + 1, post_thinking.tags(true).size)
+
+    assert_kind_of Tag, post_thinking.tags.create!(:name => 'foo')
+    assert_nil( wrong = post_thinking.tags.detect { |t| t.class != Tag },
+                message = "Expected a Tag in tags collection, got #{wrong.class}.")
+    assert_nil( wrong = post_thinking.taggings.detect { |t| t.class != Tagging },
+                message = "Expected a Tagging in taggings collection, got #{wrong.class}.")
+    assert_equal(count + 2, post_thinking.reload.tags.size)
+    assert_equal(count + 2, post_thinking.tags(true).size)
+
+    assert_nothing_raised { post_thinking.tags.concat(Tag.create!(:name => 'abc'), Tag.create!(:name => 'def')) }
+    assert_nil( wrong = post_thinking.tags.detect { |t| t.class != Tag },
+                message = "Expected a Tag in tags collection, got #{wrong.class}.")
+    assert_nil( wrong = post_thinking.taggings.detect { |t| t.class != Tagging },
+                message = "Expected a Tagging in taggings collection, got #{wrong.class}.")
+    assert_equal(count + 4, post_thinking.reload.tags.size)
+    assert_equal(count + 4, post_thinking.tags(true).size)
+
+    # Raises if the wrong reflection name is used to set the Edge belongs_to
+    assert_nothing_raised { vertices(:vertex_1).sinks << vertices(:vertex_5) }
+  end
+
+  def test_add_to_join_table_with_no_id
+    assert_nothing_raised { vertices(:vertex_1).sinks << vertices(:vertex_5) }
+  end
+
+  def test_has_many_through_collection_size_doesnt_load_target_if_not_loaded
+    author = authors(:david)
+    assert_equal 10, author.comments.size
+    assert !author.comments.loaded?
+  end
+
+  def test_has_many_through_collection_size_uses_counter_cache_if_it_exists
+    c = categories(:general)
+    c.categorizations_count = 100
+    assert_equal 100, c.categorizations.size
+    assert !c.categorizations.loaded?
+  end
+
+  def test_adding_junk_to_has_many_through_should_raise_type_mismatch
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { posts(:thinking).tags << "Uhh what now?" }
+  end
+
+  def test_adding_to_has_many_through_should_return_self
+    tags = posts(:thinking).tags
+    assert_equal tags, posts(:thinking).tags.push(tags(:general))
+  end
+
+  def test_delete_associate_when_deleting_from_has_many_through_with_nonstandard_id
+    count = books(:awdr).references.count
+    references_before = books(:awdr).references
+    book = Book.create!(:name => 'Getting Real')
+    book_awdr = books(:awdr)
+    book_awdr.references << book
+    assert_equal(count + 1, book_awdr.references(true).size)
+
+    assert_nothing_raised { book_awdr.references.delete(book) }
+    assert_equal(count, book_awdr.references.size)
+    assert_equal(count, book_awdr.references(true).size)
+    assert_equal(references_before.sort, book_awdr.references.sort)
+  end
+
+  def test_delete_associate_when_deleting_from_has_many_through
+    count = posts(:thinking).tags.count
+    tags_before = posts(:thinking).tags.sort
+    tag = Tag.create!(:name => 'doomed')
+    post_thinking = posts(:thinking)
+    post_thinking.tags << tag
+    assert_equal(count + 1, post_thinking.taggings(true).size)
+    assert_equal(count + 1, post_thinking.reload.tags(true).size)
+    assert_not_equal(tags_before, post_thinking.tags.sort)
+
+    assert_nothing_raised { post_thinking.tags.delete(tag) }
+    assert_equal(count, post_thinking.tags.size)
+    assert_equal(count, post_thinking.tags(true).size)
+    assert_equal(count, post_thinking.taggings(true).size)
+    assert_equal(tags_before, post_thinking.tags.sort)
+  end
+
+  def test_delete_associate_when_deleting_from_has_many_through_with_multiple_tags
+    count = posts(:thinking).tags.count
+    tags_before = posts(:thinking).tags.sort
+    doomed = Tag.create!(:name => 'doomed')
+    doomed2 = Tag.create!(:name => 'doomed2')
+    quaked = Tag.create!(:name => 'quaked')
+    post_thinking = posts(:thinking)
+    post_thinking.tags << doomed << doomed2
+    assert_equal(count + 2, post_thinking.reload.tags(true).size)
+
+    assert_nothing_raised { post_thinking.tags.delete(doomed, doomed2, quaked) }
+    assert_equal(count, post_thinking.tags.size)
+    assert_equal(count, post_thinking.tags(true).size)
+    assert_equal(tags_before, post_thinking.tags.sort)
+  end
+
+  def test_deleting_junk_from_has_many_through_should_raise_type_mismatch
+    assert_raise(ActiveRecord::AssociationTypeMismatch) { posts(:thinking).tags.delete(Object.new) }
+  end
+
+  def test_deleting_by_fixnum_id_from_has_many_through
+    post = posts(:thinking)
+
+    assert_difference 'post.tags.count', -1 do
+      assert_equal 1, post.tags.delete(1).size
+    end
+
+    assert_equal 0, post.tags.size
+  end
+
+  def test_deleting_by_string_id_from_has_many_through
+    post = posts(:thinking)
+
+    assert_difference 'post.tags.count', -1 do
+      assert_equal 1, post.tags.delete('1').size
+    end
+
+    assert_equal 0, post.tags.size
+  end
+
+  def test_has_many_through_sum_uses_calculations
+    assert_nothing_raised { authors(:david).comments.sum(:post_id) }
+  end
+
+  def test_calculations_on_has_many_through_should_disambiguate_fields
+    assert_nothing_raised { authors(:david).categories.maximum(:id) }
+  end
+
+  def test_calculations_on_has_many_through_should_not_disambiguate_fields_unless_necessary
+    assert_nothing_raised { authors(:david).categories.maximum("categories.id") }
+  end
+
+  def test_has_many_through_has_many_with_sti
+    assert_equal [comments(:does_it_hurt)], authors(:david).special_post_comments
+  end
+
+  def test_uniq_has_many_through_should_retain_order
+    comment_ids = authors(:david).comments.map(&:id)
+    assert_equal comment_ids.sort, authors(:david).ordered_uniq_comments.map(&:id)
+    assert_equal comment_ids.sort.reverse, authors(:david).ordered_uniq_comments_desc.map(&:id)
+  end
+
+  def test_polymorphic_has_many
+    expected = taggings(:welcome_general)
+    p = Post.all.merge!(:includes => :taggings).find(posts(:welcome).id)
+    assert_no_queries {assert p.taggings.include?(expected)}
+    assert posts(:welcome).taggings.include?(taggings(:welcome_general))
+  end
+
+  def test_polymorphic_has_one
+    expected = posts(:welcome)
+
+    tagging  = Tagging.all.merge!(:includes => :taggable).find(taggings(:welcome_general).id)
+    assert_no_queries { assert_equal expected, tagging.taggable}
+  end
+
+  def test_polymorphic_belongs_to
+    p = Post.all.merge!(:includes => {:taggings => :taggable}).find(posts(:welcome).id)
+    assert_no_queries {assert_equal posts(:welcome), p.taggings.first.taggable}
+  end
+
+  def test_preload_polymorphic_has_many_through
+    posts           = Post.all.merge!(:order => 'posts.id').to_a
+    posts_with_tags = Post.all.merge!(:includes => :tags, :order => 'posts.id').to_a
+    assert_equal posts.length, posts_with_tags.length
+    posts.length.times do |i|
+      assert_equal posts[i].tags.length, assert_no_queries { posts_with_tags[i].tags.length }
+    end
+  end
+
+  def test_preload_polymorph_many_types
+    taggings = Tagging.all.merge!(:includes => :taggable, :where => ['taggable_type != ?', 'FakeModel']).to_a
+    assert_no_queries do
+      taggings.first.taggable.id
+      taggings[1].taggable.id
+    end
+
+    taggables = taggings.map(&:taggable)
+    assert taggables.include?(items(:dvd))
+    assert taggables.include?(posts(:welcome))
+  end
+
+  def test_preload_nil_polymorphic_belongs_to
+    assert_nothing_raised do
+      Tagging.all.merge!(:includes => :taggable, :where => ['taggable_type IS NULL']).to_a
+    end
+  end
+
+  def test_preload_polymorphic_has_many
+    posts               = Post.all.merge!(:order => 'posts.id').to_a
+    posts_with_taggings = Post.all.merge!(:includes => :taggings, :order => 'posts.id').to_a
+    assert_equal posts.length, posts_with_taggings.length
+    posts.length.times do |i|
+      assert_equal posts[i].taggings.length, assert_no_queries { posts_with_taggings[i].taggings.length }
+    end
+  end
+
+  def test_belongs_to_shared_parent
+    comments = Comment.all.merge!(:includes => :post, :where => 'post_id = 1').to_a
+    assert_no_queries do
+      assert_equal comments.first.post, comments[1].post
+    end
+  end
+
+  def test_has_many_through_include_uses_array_include_after_loaded
+    david = authors(:david)
+    david.categories.load_target
+
+    category = david.categories.first
+
+    assert_no_queries do
+      assert david.categories.loaded?
+      assert david.categories.include?(category)
+    end
+  end
+
+  def test_has_many_through_include_checks_if_record_exists_if_target_not_loaded
+    david = authors(:david)
+    category = david.categories.first
+
+    david.reload
+    assert ! david.categories.loaded?
+    assert_queries(1) do
+      assert david.categories.include?(category)
+    end
+    assert ! david.categories.loaded?
+  end
+
+  def test_has_many_through_include_returns_false_for_non_matching_record_to_verify_scoping
+    david = authors(:david)
+    category = Category.create!(:name => 'Not Associated')
+
+    assert ! david.categories.loaded?
+    assert ! david.categories.include?(category)
+  end
+
+  def test_has_many_through_goes_through_all_sti_classes
+    sub_sti_post = SubStiPost.create!(:title => 'test', :body => 'test', :author_id => 1)
+    new_comment = sub_sti_post.comments.create(:body => 'test')
+
+    assert_equal [9, 10, new_comment.id], authors(:david).sti_post_comments.map(&:id).sort
+  end
+
+  def test_has_many_with_pluralize_table_names_false
+    aircraft = Aircraft.create!(:name => "Airbus 380")
+    engine = Engine.create!(:car_id => aircraft.id)
+    assert_equal aircraft.engines, [engine]
+  end
+
+  private
+    # create dynamic Post models to allow different dependency options
+    def find_post_with_dependency(post_id, association, association_name, dependency)
+      class_name = "PostWith#{association.to_s.classify}#{dependency.to_s.classify}"
+      Post.find(post_id).update_columns type: class_name
+      klass = Object.const_set(class_name, Class.new(ActiveRecord::Base))
+      klass.table_name = 'posts'
+      klass.send(association, association_name, :as => :taggable, :dependent => dependency)
+      klass.find(post_id)
+    end
+end
diff --git a/activerecord/test/cases/associations/nested_through_associations_test.rb b/activerecord/test/cases/associations/nested_through_associations_test.rb
new file mode 100644
index 0000000000..31b68c940e
--- /dev/null
+++ b/activerecord/test/cases/associations/nested_through_associations_test.rb
@@ -0,0 +1,579 @@
+require "cases/helper"
+require 'models/author'
+require 'models/post'
+require 'models/person'
+require 'models/reference'
+require 'models/job'
+require 'models/reader'
+require 'models/comment'
+require 'models/tag'
+require 'models/tagging'
+require 'models/subscriber'
+require 'models/book'
+require 'models/subscription'
+require 'models/rating'
+require 'models/member'
+require 'models/member_detail'
+require 'models/member_type'
+require 'models/sponsor'
+require 'models/club'
+require 'models/organization'
+require 'models/category'
+require 'models/categorization'
+require 'models/membership'
+require 'models/essay'
+
+class NestedThroughAssociationsTest < ActiveRecord::TestCase
+  fixtures :authors, :books, :posts, :subscriptions, :subscribers, :tags, :taggings,
+           :people, :readers, :references, :jobs, :ratings, :comments, :members, :member_details,
+           :member_types, :sponsors, :clubs, :organizations, :categories, :categories_posts,
+           :categorizations, :memberships, :essays
+
+  # Through associations can either use the has_many or has_one macros.
+  #
+  # has_many
+  #   - Source reflection can be has_many, has_one, belongs_to or has_and_belongs_to_many
+  #   - Through reflection can be has_many, has_one, belongs_to or has_and_belongs_to_many
+  #
+  # has_one
+  #   - Source reflection can be has_one or belongs_to
+  #   - Through reflection can be has_one or belongs_to
+  #
+  # Additionally, the source reflection and/or through reflection may be subject to
+  # polymorphism and/or STI.
+  #
+  # When testing these, we need to make sure it works via loading the association directly, or
+  # joining the association, or including the association. We also need to ensure that associations
+  # are readonly where relevant.
+
+  # has_many through
+  # Source: has_many through
+  # Through: has_many
+  def test_has_many_through_has_many_with_has_many_through_source_reflection
+    general = tags(:general)
+    assert_equal [general, general], authors(:david).tags
+  end
+
+  def test_has_many_through_has_many_with_has_many_through_source_reflection_preload
+    authors = assert_queries(5) { Author.includes(:tags).to_a }
+    general = tags(:general)
+
+    assert_no_queries do
+      assert_equal [general, general], authors.first.tags
+    end
+  end
+
+  def test_has_many_through_has_many_with_has_many_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Author.where('tags.id' => tags(:general).id),
+      [authors(:david)], :tags
+    )
+
+    # This ensures that the polymorphism of taggings is being observed correctly
+    authors = Author.joins(:tags).where('taggings.taggable_type' => 'FakeModel')
+    assert authors.empty?
+  end
+
+  # has_many through
+  # Source: has_many
+  # Through: has_many through
+  def test_has_many_through_has_many_through_with_has_many_source_reflection
+    luke, david = subscribers(:first), subscribers(:second)
+    assert_equal [luke, david, david], authors(:david).subscribers.order('subscribers.nick')
+  end
+
+  def test_has_many_through_has_many_through_with_has_many_source_reflection_preload
+    luke, david = subscribers(:first), subscribers(:second)
+    authors = assert_queries(4) { Author.includes(:subscribers).to_a }
+    assert_no_queries do
+      assert_equal [luke, david, david], authors.first.subscribers.sort_by(&:nick)
+    end
+  end
+
+  def test_has_many_through_has_many_through_with_has_many_source_reflection_preload_via_joins
+    # All authors with subscribers where one of the subscribers' nick is 'alterself'
+    assert_includes_and_joins_equal(
+      Author.where('subscribers.nick' => 'alterself'),
+      [authors(:david)], :subscribers
+    )
+  end
+
+  # has_many through
+  # Source: has_one through
+  # Through: has_one
+  def test_has_many_through_has_one_with_has_one_through_source_reflection
+    assert_equal [member_types(:founding)], members(:groucho).nested_member_types
+  end
+
+  def test_has_many_through_has_one_with_has_one_through_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:nested_member_types).to_a }
+    founding = member_types(:founding)
+    assert_no_queries do
+      assert_equal [founding], members.first.nested_member_types
+    end
+  end
+
+  def test_has_many_through_has_one_with_has_one_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where('member_types.id' => member_types(:founding).id),
+      [members(:groucho)], :nested_member_types
+    )
+  end
+
+  # has_many through
+  # Source: has_one
+  # Through: has_one through
+  def test_has_many_through_has_one_through_with_has_one_source_reflection
+    assert_equal [sponsors(:moustache_club_sponsor_for_groucho)], members(:groucho).nested_sponsors
+  end
+
+  def test_has_many_through_has_one_through_with_has_one_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:nested_sponsors).to_a }
+    mustache = sponsors(:moustache_club_sponsor_for_groucho)
+    assert_no_queries(ignore_none: false) do
+      assert_equal [mustache], members.first.nested_sponsors
+    end
+  end
+
+  def test_has_many_through_has_one_through_with_has_one_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where('sponsors.id' => sponsors(:moustache_club_sponsor_for_groucho).id),
+      [members(:groucho)], :nested_sponsors
+    )
+  end
+
+  # has_many through
+  # Source: has_many through
+  # Through: has_one
+  def test_has_many_through_has_one_with_has_many_through_source_reflection
+    groucho_details, other_details = member_details(:groucho), member_details(:some_other_guy)
+
+    assert_equal [groucho_details, other_details],
+                 members(:groucho).organization_member_details.order('member_details.id')
+  end
+
+  def test_has_many_through_has_one_with_has_many_through_source_reflection_preload
+    ActiveRecord::Base.connection.table_alias_length  # preheat cache
+    members = assert_queries(4) { Member.includes(:organization_member_details).to_a.sort_by(&:id) }
+    groucho_details, other_details = member_details(:groucho), member_details(:some_other_guy)
+
+    assert_no_queries do
+      assert_equal [groucho_details, other_details], members.first.organization_member_details.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_one_with_has_many_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where('member_details.id' => member_details(:groucho).id).order('member_details.id'),
+      [members(:groucho), members(:some_other_guy)], :organization_member_details
+    )
+
+    members = Member.joins(:organization_member_details).
+                     where('member_details.id' => 9)
+    assert members.empty?
+  end
+
+  # has_many through
+  # Source: has_many
+  # Through: has_one through
+  def test_has_many_through_has_one_through_with_has_many_source_reflection
+    groucho_details, other_details = member_details(:groucho), member_details(:some_other_guy)
+
+    assert_equal [groucho_details, other_details],
+                 members(:groucho).organization_member_details_2.order('member_details.id')
+  end
+
+  def test_has_many_through_has_one_through_with_has_many_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:organization_member_details_2).to_a.sort_by(&:id) }
+    groucho_details, other_details = member_details(:groucho), member_details(:some_other_guy)
+
+    # postgresql test if randomly executed then executes "SHOW max_identifier_length". Hence
+    # the need to ignore certain predefined sqls that deal with system calls.
+    assert_no_queries(ignore_none: false) do
+      assert_equal [groucho_details, other_details], members.first.organization_member_details_2.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_one_through_with_has_many_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where('member_details.id' => member_details(:groucho).id).order('member_details.id'),
+      [members(:groucho), members(:some_other_guy)], :organization_member_details_2
+    )
+
+    members = Member.joins(:organization_member_details_2).
+                     where('member_details.id' => 9)
+    assert members.empty?
+  end
+
+  # has_many through
+  # Source: has_and_belongs_to_many
+  # Through: has_many
+  def test_has_many_through_has_many_with_has_and_belongs_to_many_source_reflection
+    general, cooking = categories(:general), categories(:cooking)
+
+    assert_equal [general, cooking], authors(:bob).post_categories.order('categories.id')
+  end
+
+  def test_has_many_through_has_many_with_has_and_belongs_to_many_source_reflection_preload
+    authors = assert_queries(4) { Author.includes(:post_categories).to_a.sort_by(&:id) }
+    general, cooking = categories(:general), categories(:cooking)
+
+    assert_no_queries do
+      assert_equal [general, cooking], authors[2].post_categories.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_many_with_has_and_belongs_to_many_source_reflection_preload_via_joins
+    # preload table schemas
+    Author.joins(:post_categories).first
+
+    assert_includes_and_joins_equal(
+      Author.where('categories.id' => categories(:cooking).id),
+      [authors(:bob)], :post_categories
+    )
+  end
+
+  # has_many through
+  # Source: has_many
+  # Through: has_and_belongs_to_many
+  def test_has_many_through_has_and_belongs_to_many_with_has_many_source_reflection
+    greetings, more = comments(:greetings), comments(:more_greetings)
+
+    assert_equal [greetings, more], categories(:technology).post_comments.order('comments.id')
+  end
+
+  def test_has_many_through_has_and_belongs_to_many_with_has_many_source_reflection_preload
+    Category.includes(:post_comments).to_a # preheat cache
+    categories = assert_queries(4) { Category.includes(:post_comments).to_a.sort_by(&:id) }
+    greetings, more = comments(:greetings), comments(:more_greetings)
+
+    assert_no_queries do
+      assert_equal [greetings, more], categories[1].post_comments.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_and_belongs_to_many_with_has_many_source_reflection_preload_via_joins
+    # preload table schemas
+    Category.joins(:post_comments).first
+
+    assert_includes_and_joins_equal(
+      Category.where('comments.id' => comments(:more_greetings).id).order('categories.id'),
+      [categories(:general), categories(:technology)], :post_comments
+    )
+  end
+
+  # has_many through
+  # Source: has_many through a habtm
+  # Through: has_many through
+  def test_has_many_through_has_many_with_has_many_through_habtm_source_reflection
+    greetings, more = comments(:greetings), comments(:more_greetings)
+
+    assert_equal [greetings, more], authors(:bob).category_post_comments.order('comments.id')
+  end
+
+  def test_has_many_through_has_many_with_has_many_through_habtm_source_reflection_preload
+    authors = assert_queries(6) { Author.includes(:category_post_comments).to_a.sort_by(&:id) }
+    greetings, more = comments(:greetings), comments(:more_greetings)
+
+    assert_no_queries do
+      assert_equal [greetings, more], authors[2].category_post_comments.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_has_many_with_has_many_through_habtm_source_reflection_preload_via_joins
+    # preload table schemas
+    Author.joins(:category_post_comments).first
+
+    assert_includes_and_joins_equal(
+      Author.where('comments.id' => comments(:does_it_hurt).id).order('authors.id'),
+      [authors(:david), authors(:mary)], :category_post_comments
+    )
+  end
+
+  # has_many through
+  # Source: belongs_to
+  # Through: has_many through
+  def test_has_many_through_has_many_through_with_belongs_to_source_reflection
+    assert_equal [tags(:general), tags(:general)], authors(:david).tagging_tags
+  end
+
+  def test_has_many_through_has_many_through_with_belongs_to_source_reflection_preload
+    authors = assert_queries(5) { Author.includes(:tagging_tags).to_a }
+    general = tags(:general)
+
+    assert_no_queries do
+      assert_equal [general, general], authors.first.tagging_tags
+    end
+  end
+
+  def test_has_many_through_has_many_through_with_belongs_to_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Author.where('tags.id' => tags(:general).id),
+      [authors(:david)], :tagging_tags
+    )
+  end
+
+  # has_many through
+  # Source: has_many through
+  # Through: belongs_to
+  def test_has_many_through_belongs_to_with_has_many_through_source_reflection
+    welcome_general, thinking_general = taggings(:welcome_general), taggings(:thinking_general)
+
+    assert_equal [welcome_general, thinking_general],
+                 categorizations(:david_welcome_general).post_taggings.order('taggings.id')
+  end
+
+  def test_has_many_through_belongs_to_with_has_many_through_source_reflection_preload
+    categorizations = assert_queries(4) { Categorization.includes(:post_taggings).to_a.sort_by(&:id) }
+    welcome_general, thinking_general = taggings(:welcome_general), taggings(:thinking_general)
+
+    assert_no_queries do
+      assert_equal [welcome_general, thinking_general], categorizations.first.post_taggings.sort_by(&:id)
+    end
+  end
+
+  def test_has_many_through_belongs_to_with_has_many_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Categorization.where('taggings.id' => taggings(:welcome_general).id).order('taggings.id'),
+      [categorizations(:david_welcome_general)], :post_taggings
+    )
+  end
+
+  # has_one through
+  # Source: has_one through
+  # Through: has_one
+  def test_has_one_through_has_one_with_has_one_through_source_reflection
+    assert_equal member_types(:founding), members(:groucho).nested_member_type
+  end
+
+  def test_has_one_through_has_one_with_has_one_through_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:nested_member_type).to_a.sort_by(&:id) }
+    founding = member_types(:founding)
+
+    assert_no_queries do
+      assert_equal founding, members.first.nested_member_type
+    end
+  end
+
+  def test_has_one_through_has_one_with_has_one_through_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where('member_types.id' => member_types(:founding).id),
+      [members(:groucho)], :nested_member_type
+    )
+  end
+
+  # has_one through
+  # Source: belongs_to
+  # Through: has_one through
+  def test_has_one_through_has_one_through_with_belongs_to_source_reflection
+    assert_equal categories(:general), members(:groucho).club_category
+  end
+
+  def test_joins_and_includes_from_through_models_not_included_in_association
+    prev_default_scope = Club.default_scopes
+
+    [:includes, :preload, :joins, :eager_load].each do |q|
+      Club.default_scopes = [proc { Club.send(q, :category) }]
+      assert_equal categories(:general), members(:groucho).reload.club_category
+    end
+  ensure
+    Club.default_scopes = prev_default_scope
+  end
+
+  def test_has_one_through_has_one_through_with_belongs_to_source_reflection_preload
+    members = assert_queries(4) { Member.includes(:club_category).to_a.sort_by(&:id) }
+    general = categories(:general)
+
+    assert_no_queries do
+      assert_equal general, members.first.club_category
+    end
+  end
+
+  def test_has_one_through_has_one_through_with_belongs_to_source_reflection_preload_via_joins
+    assert_includes_and_joins_equal(
+      Member.where('categories.id' => categories(:technology).id),
+      [members(:blarpy_winkup)], :club_category
+    )
+  end
+
+  def test_distinct_has_many_through_a_has_many_through_association_on_source_reflection
+    author = authors(:david)
+    assert_equal [tags(:general)], author.distinct_tags
+  end
+
+  def test_distinct_has_many_through_a_has_many_through_association_on_through_reflection
+    author = authors(:david)
+    assert_equal [subscribers(:first), subscribers(:second)],
+                 author.distinct_subscribers.order('subscribers.nick')
+  end
+
+  def test_nested_has_many_through_with_a_table_referenced_multiple_times
+    author = authors(:bob)
+    assert_equal [posts(:misc_by_bob), posts(:misc_by_mary), posts(:other_by_bob), posts(:other_by_mary)],
+                 author.similar_posts.sort_by(&:id)
+
+    # Mary and Bob both have posts in misc, but they are the only ones.
+    authors = Author.joins(:similar_posts).where('posts.id' => posts(:misc_by_bob).id)
+    assert_equal [authors(:mary), authors(:bob)], authors.distinct.sort_by(&:id)
+
+    # Check the polymorphism of taggings is being observed correctly (in both joins)
+    authors = Author.joins(:similar_posts).where('taggings.taggable_type' => 'FakeModel')
+    assert authors.empty?
+    authors = Author.joins(:similar_posts).where('taggings_authors_join.taggable_type' => 'FakeModel')
+    assert authors.empty?
+  end
+
+  def test_has_many_through_with_foreign_key_option_on_through_reflection
+    assert_equal [posts(:welcome), posts(:authorless)], people(:david).agents_posts.order('posts.id')
+    assert_equal [authors(:david)], references(:david_unicyclist).agents_posts_authors
+
+    references = Reference.joins(:agents_posts_authors).where('authors.id' => authors(:david).id)
+    assert_equal [references(:david_unicyclist)], references
+  end
+
+  def test_has_many_through_with_foreign_key_option_on_source_reflection
+    assert_equal [people(:michael), people(:susan)], jobs(:unicyclist).agents.order('people.id')
+
+    jobs = Job.joins(:agents)
+    assert_equal [jobs(:unicyclist), jobs(:unicyclist)], jobs
+  end
+
+  def test_has_many_through_with_sti_on_through_reflection
+    ratings = posts(:sti_comments).special_comments_ratings.sort_by(&:id)
+    assert_equal [ratings(:special_comment_rating), ratings(:sub_special_comment_rating)], ratings
+
+    # Ensure STI is respected in the join
+    scope = Post.joins(:special_comments_ratings).where(:id => posts(:sti_comments).id)
+    assert scope.where("comments.type" => "Comment").empty?
+    assert !scope.where("comments.type" => "SpecialComment").empty?
+    assert !scope.where("comments.type" => "SubSpecialComment").empty?
+  end
+
+  def test_has_many_through_with_sti_on_nested_through_reflection
+    taggings = posts(:sti_comments).special_comments_ratings_taggings
+    assert_equal [taggings(:special_comment_rating)], taggings
+
+    scope = Post.joins(:special_comments_ratings_taggings).where(:id => posts(:sti_comments).id)
+    assert scope.where("comments.type" => "Comment").empty?
+    assert !scope.where("comments.type" => "SpecialComment").empty?
+  end
+
+  def test_nested_has_many_through_writers_should_raise_error
+    david = authors(:david)
+    subscriber = subscribers(:first)
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers = [subscriber]
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscriber_ids = [subscriber.id]
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers << subscriber
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers.delete(subscriber)
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers.clear
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers.build
+    end
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      david.subscribers.create
+    end
+  end
+
+  def test_nested_has_one_through_writers_should_raise_error
+    groucho = members(:groucho)
+    founding = member_types(:founding)
+
+    assert_raises(ActiveRecord::HasManyThroughNestedAssociationsAreReadonly) do
+      groucho.nested_member_type = founding
+    end
+  end
+
+  def test_nested_has_many_through_with_conditions_on_through_associations
+    assert_equal [tags(:blue)], authors(:bob).misc_post_first_blue_tags
+  end
+
+  def test_nested_has_many_through_with_conditions_on_through_associations_preload
+    assert Author.where('tags.id' => 100).joins(:misc_post_first_blue_tags).empty?
+
+    authors = assert_queries(3) { Author.includes(:misc_post_first_blue_tags).to_a.sort_by(&:id) }
+    blue = tags(:blue)
+
+    assert_no_queries do
+      assert_equal [blue], authors[2].misc_post_first_blue_tags
+    end
+  end
+
+  def test_nested_has_many_through_with_conditions_on_through_associations_preload_via_joins
+    # Pointless condition to force single-query loading
+    assert_includes_and_joins_equal(
+      Author.where('tags.id = tags.id').references(:tags),
+      [authors(:bob)], :misc_post_first_blue_tags
+    )
+  end
+
+  def test_nested_has_many_through_with_conditions_on_source_associations
+    assert_equal [tags(:blue)], authors(:bob).misc_post_first_blue_tags_2
+  end
+
+  def test_nested_has_many_through_with_conditions_on_source_associations_preload
+    authors = assert_queries(4) { Author.includes(:misc_post_first_blue_tags_2).to_a.sort_by(&:id) }
+    blue = tags(:blue)
+
+    assert_no_queries do
+      assert_equal [blue], authors[2].misc_post_first_blue_tags_2
+    end
+  end
+
+  def test_nested_has_many_through_with_conditions_on_source_associations_preload_via_joins
+    # Pointless condition to force single-query loading
+    assert_includes_and_joins_equal(
+      Author.where('tags.id = tags.id').references(:tags),
+      [authors(:bob)], :misc_post_first_blue_tags_2
+    )
+  end
+
+  def test_nested_has_many_through_with_foreign_key_option_on_the_source_reflection_through_reflection
+    assert_equal [categories(:general)], organizations(:nsa).author_essay_categories
+
+    organizations = Organization.joins(:author_essay_categories).
+                                 where('categories.id' => categories(:general).id)
+    assert_equal [organizations(:nsa)], organizations
+
+    assert_equal categories(:general), organizations(:nsa).author_owned_essay_category
+
+    organizations = Organization.joins(:author_owned_essay_category).
+                                 where('categories.id' => categories(:general).id)
+    assert_equal [organizations(:nsa)], organizations
+  end
+
+  def test_nested_has_many_through_should_not_be_autosaved
+    c = Categorization.new
+    c.author = authors(:david)
+    c.post_taggings.to_a
+    assert !c.post_taggings.empty?
+    c.save
+    assert !c.post_taggings.empty?
+  end
+
+  private
+
+    def assert_includes_and_joins_equal(query, expected, association)
+      actual = assert_queries(1) { query.joins(association).to_a.uniq }
+      assert_equal expected, actual
+
+      actual = assert_queries(1) { query.includes(association).to_a.uniq }
+      assert_equal expected, actual
+    end
+end
diff --git a/activerecord/test/cases/associations/required_test.rb b/activerecord/test/cases/associations/required_test.rb
new file mode 100644
index 0000000000..a6934a056e
--- /dev/null
+++ b/activerecord/test/cases/associations/required_test.rb
@@ -0,0 +1,82 @@
+require "cases/helper"
+
+class RequiredAssociationsTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  class Parent < ActiveRecord::Base
+  end
+
+  class Child < ActiveRecord::Base
+  end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :parents, force: true
+    @connection.create_table :children, force: true do |t|
+      t.belongs_to :parent
+    end
+  end
+
+  teardown do
+    @connection.execute("DROP TABLE IF EXISTS parents")
+    @connection.execute("DROP TABLE IF EXISTS children")
+  end
+
+  test "belongs_to associations are not required by default" do
+    model = subclass_of(Child) do
+      belongs_to :parent, inverse_of: false,
+        class_name: "RequiredAssociationsTest::Parent"
+    end
+
+    assert model.new.save
+    assert model.new(parent: Parent.new).save
+  end
+
+  test "required belongs_to associations have presence validated" do
+    model = subclass_of(Child) do
+      belongs_to :parent, required: true, inverse_of: false,
+        class_name: "RequiredAssociationsTest::Parent"
+    end
+
+    record = model.new
+    assert_not record.save
+    assert_equal ["Parent can't be blank"], record.errors.full_messages
+
+    record.parent = Parent.new
+    assert record.save
+  end
+
+  test "has_one associations are not required by default" do
+    model = subclass_of(Parent) do
+      has_one :child, inverse_of: false,
+        class_name: "RequiredAssociationsTest::Child"
+    end
+
+    assert model.new.save
+    assert model.new(child: Child.new).save
+  end
+
+  test "required has_one associations have presence validated" do
+    model = subclass_of(Parent) do
+      has_one :child, required: true, inverse_of: false,
+        class_name: "RequiredAssociationsTest::Child"
+    end
+
+    record = model.new
+    assert_not record.save
+    assert_equal ["Child can't be blank"], record.errors.full_messages
+
+    record.child = Child.new
+    assert record.save
+  end
+
+  private
+
+  def subclass_of(klass, &block)
+    subclass = Class.new(klass, &block)
+    def subclass.name
+      superclass.name
+    end
+    subclass
+  end
+end
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
new file mode 100644
index 0000000000..f663b5490c
--- /dev/null
+++ b/activerecord/test/cases/associations_test.rb
@@ -0,0 +1,353 @@
+require "cases/helper"
+require 'models/computer'
+require 'models/developer'
+require 'models/project'
+require 'models/company'
+require 'models/categorization'
+require 'models/category'
+require 'models/post'
+require 'models/author'
+require 'models/comment'
+require 'models/tag'
+require 'models/tagging'
+require 'models/person'
+require 'models/reader'
+require 'models/parrot'
+require 'models/ship_part'
+require 'models/ship'
+require 'models/liquid'
+require 'models/molecule'
+require 'models/electron'
+require 'models/man'
+require 'models/interest'
+
+class AssociationsTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :developers, :projects, :developers_projects,
+           :computers, :people, :readers
+
+  def test_eager_loading_should_not_change_count_of_children
+    liquid = Liquid.create(:name => 'salty')
+    molecule = liquid.molecules.create(:name => 'molecule_1')
+    molecule.electrons.create(:name => 'electron_1')
+    molecule.electrons.create(:name => 'electron_2')
+
+    liquids = Liquid.includes(:molecules => :electrons).references(:molecules).where('molecules.id is not null')
+    assert_equal 1, liquids[0].molecules.length
+  end
+
+  def test_clear_association_cache_stored
+    firm = Firm.find(1)
+    assert_kind_of Firm, firm
+
+    firm.clear_association_cache
+    assert_equal Firm.find(1).clients.collect{ |x| x.name }.sort, firm.clients.collect{ |x| x.name }.sort
+  end
+
+  def test_clear_association_cache_new_record
+     firm            = Firm.new
+     client_stored   = Client.find(3)
+     client_new      = Client.new
+     client_new.name = "The Joneses"
+     clients         = [ client_stored, client_new ]
+
+     firm.clients    << clients
+     assert_equal clients.map(&:name).to_set, firm.clients.map(&:name).to_set
+
+     firm.clear_association_cache
+     assert_equal clients.map(&:name).to_set, firm.clients.map(&:name).to_set
+  end
+
+  def test_loading_the_association_target_should_keep_child_records_marked_for_destruction
+    ship = Ship.create!(:name => "The good ship Dollypop")
+    part = ship.parts.create!(:name => "Mast")
+    part.mark_for_destruction
+    ship.parts.send(:load_target)
+    assert ship.parts[0].marked_for_destruction?
+  end
+
+  def test_loading_the_association_target_should_load_most_recent_attributes_for_child_records_marked_for_destruction
+    ship = Ship.create!(:name => "The good ship Dollypop")
+    part = ship.parts.create!(:name => "Mast")
+    part.mark_for_destruction
+    ShipPart.find(part.id).update_columns(name: 'Deck')
+    ship.parts.send(:load_target)
+    assert_equal 'Deck', ship.parts[0].name
+  end
+
+
+  def test_include_with_order_works
+    assert_nothing_raised {Account.all.merge!(:order => 'id', :includes => :firm).first}
+    assert_nothing_raised {Account.all.merge!(:order => :id, :includes => :firm).first}
+  end
+
+  def test_bad_collection_keys
+    assert_raise(ArgumentError, 'ActiveRecord should have barked on bad collection keys') do
+      Class.new(ActiveRecord::Base).has_many(:wheels, :name => 'wheels')
+    end
+  end
+
+  def test_should_construct_new_finder_sql_after_create
+    person = Person.new :first_name => 'clark'
+    assert_equal [], person.readers.to_a
+    person.save!
+    reader = Reader.create! :person => person, :post => Post.new(:title => "foo", :body => "bar")
+    assert person.readers.find(reader.id)
+  end
+
+  def test_force_reload
+    firm = Firm.new("name" => "A New Firm, Inc")
+    firm.save
+    firm.clients.each {} # forcing to load all clients
+    assert firm.clients.empty?, "New firm shouldn't have client objects"
+    assert_equal 0, firm.clients.size, "New firm should have 0 clients"
+
+    client = Client.new("name" => "TheClient.com", "firm_id" => firm.id)
+    client.save
+
+    assert firm.clients.empty?, "New firm should have cached no client objects"
+    assert_equal 0, firm.clients.size, "New firm should have cached 0 clients count"
+
+    assert !firm.clients(true).empty?, "New firm should have reloaded client objects"
+    assert_equal 1, firm.clients(true).size, "New firm should have reloaded clients count"
+  end
+
+  def test_using_limitable_reflections_helper
+    using_limitable_reflections = lambda { |reflections| Tagging.all.send :using_limitable_reflections?, reflections }
+    belongs_to_reflections = [Tagging.reflect_on_association(:tag), Tagging.reflect_on_association(:super_tag)]
+    has_many_reflections = [Tag.reflect_on_association(:taggings), Developer.reflect_on_association(:projects)]
+    mixed_reflections = (belongs_to_reflections + has_many_reflections).uniq
+    assert using_limitable_reflections.call(belongs_to_reflections), "Belong to associations are limitable"
+    assert !using_limitable_reflections.call(has_many_reflections), "All has many style associations are not limitable"
+    assert !using_limitable_reflections.call(mixed_reflections), "No collection associations (has many style) should pass"
+  end
+
+  def test_force_reload_is_uncached
+    firm = Firm.create!("name" => "A New Firm, Inc")
+    Client.create!("name" => "TheClient.com", :firm => firm)
+    ActiveRecord::Base.cache do
+      firm.clients.each {}
+      assert_queries(0) { assert_not_nil firm.clients.each {} }
+      assert_queries(1) { assert_not_nil firm.clients(true).each {} }
+    end
+  end
+
+  def test_association_with_references
+    firm = companies(:first_firm)
+    assert_equal ['foo'], firm.association_with_references.references_values
+  end
+
+end
+
+class AssociationProxyTest < ActiveRecord::TestCase
+  fixtures :authors, :posts, :categorizations, :categories, :developers, :projects, :developers_projects
+
+  def test_push_does_not_load_target
+    david = authors(:david)
+
+    david.posts << (post = Post.new(:title => "New on Edge", :body => "More cool stuff!"))
+    assert !david.posts.loaded?
+    assert david.posts.include?(post)
+  end
+
+  def test_push_has_many_through_does_not_load_target
+    david = authors(:david)
+
+    david.categories << categories(:technology)
+    assert !david.categories.loaded?
+    assert david.categories.include?(categories(:technology))
+  end
+
+  def test_push_followed_by_save_does_not_load_target
+    david = authors(:david)
+
+    david.posts << (post = Post.new(:title => "New on Edge", :body => "More cool stuff!"))
+    assert !david.posts.loaded?
+    david.save
+    assert !david.posts.loaded?
+    assert david.posts.include?(post)
+  end
+
+  def test_push_does_not_lose_additions_to_new_record
+    josh = Author.new(:name => "Josh")
+    josh.posts << Post.new(:title => "New on Edge", :body => "More cool stuff!")
+    assert josh.posts.loaded?
+    assert_equal 1, josh.posts.size
+  end
+
+  def test_append_behaves_like_push
+    josh = Author.new(:name => "Josh")
+    josh.posts.append Post.new(:title => "New on Edge", :body => "More cool stuff!")
+    assert josh.posts.loaded?
+    assert_equal 1, josh.posts.size
+  end
+
+  def test_prepend_is_not_defined
+    josh = Author.new(:name => "Josh")
+    assert_raises(NoMethodError) { josh.posts.prepend Post.new }
+  end
+
+  def test_save_on_parent_does_not_load_target
+    david = developers(:david)
+
+    assert !david.projects.loaded?
+    david.update_columns(created_at: Time.now)
+    assert !david.projects.loaded?
+  end
+
+  def test_inspect_does_not_reload_a_not_yet_loaded_target
+    andreas = Developer.new :name => 'Andreas', :log => 'new developer added'
+    assert !andreas.audit_logs.loaded?
+    assert_match(/message: "new developer added"/, andreas.audit_logs.inspect)
+  end
+
+  def test_save_on_parent_saves_children
+    developer = Developer.create :name => "Bryan", :salary => 50_000
+    assert_equal 1, developer.reload.audit_logs.size
+  end
+
+  def test_create_via_association_with_block
+    post = authors(:david).posts.create(:title => "New on Edge") {|p| p.body = "More cool stuff!"}
+    assert_equal post.title, "New on Edge"
+    assert_equal post.body, "More cool stuff!"
+  end
+
+  def test_create_with_bang_via_association_with_block
+    post = authors(:david).posts.create!(:title => "New on Edge") {|p| p.body = "More cool stuff!"}
+    assert_equal post.title, "New on Edge"
+    assert_equal post.body, "More cool stuff!"
+  end
+
+  def test_reload_returns_association
+    david = developers(:david)
+    assert_nothing_raised do
+      assert_equal david.projects, david.projects.reload.reload
+    end
+  end
+
+  def test_proxy_association_accessor
+    david = developers(:david)
+    assert_equal david.association(:projects), david.projects.proxy_association
+  end
+
+  def test_scoped_allows_conditions
+    assert developers(:david).projects.merge!(where: 'foo').where_values.include?('foo')
+  end
+
+  test "getting a scope from an association" do
+    david = developers(:david)
+
+    assert david.projects.scope.is_a?(ActiveRecord::Relation)
+    assert_equal david.projects, david.projects.scope
+  end
+
+  test "proxy object is cached" do
+    david = developers(:david)
+    assert david.projects.equal?(david.projects)
+  end
+
+  test "inverses get set of subsets of the association" do
+    man = Man.create
+    man.interests.create
+
+    man = Man.find(man.id)
+
+    assert_queries(1) do
+      assert_equal man, man.interests.where("1=1").first.man
+    end
+  end
+
+  def test_reset_unloads_target
+    david = authors(:david)
+    david.posts.reload
+
+    assert david.posts.loaded?
+    david.posts.reset
+    assert !david.posts.loaded?
+  end
+end
+
+class OverridingAssociationsTest < ActiveRecord::TestCase
+  class DifferentPerson < ActiveRecord::Base; end
+
+  class PeopleList < ActiveRecord::Base
+    has_and_belongs_to_many :has_and_belongs_to_many, :before_add => :enlist
+    has_many :has_many, :before_add => :enlist
+    belongs_to :belongs_to
+    has_one :has_one
+  end
+
+  class DifferentPeopleList < PeopleList
+    # Different association with the same name, callbacks should be omitted here.
+    has_and_belongs_to_many :has_and_belongs_to_many, :class_name => 'DifferentPerson'
+    has_many :has_many, :class_name => 'DifferentPerson'
+    belongs_to :belongs_to, :class_name => 'DifferentPerson'
+    has_one :has_one, :class_name => 'DifferentPerson'
+  end
+
+  def test_habtm_association_redefinition_callbacks_should_differ_and_not_inherited
+    # redeclared association on AR descendant should not inherit callbacks from superclass
+    callbacks = PeopleList.before_add_for_has_and_belongs_to_many
+    assert_equal(1, callbacks.length)
+    callbacks = DifferentPeopleList.before_add_for_has_and_belongs_to_many
+    assert_equal([], callbacks)
+  end
+
+  def test_has_many_association_redefinition_callbacks_should_differ_and_not_inherited
+    # redeclared association on AR descendant should not inherit callbacks from superclass
+    callbacks = PeopleList.before_add_for_has_many
+    assert_equal(1, callbacks.length)
+    callbacks = DifferentPeopleList.before_add_for_has_many
+    assert_equal([], callbacks)
+  end
+
+  def test_habtm_association_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal(
+      PeopleList.reflect_on_association(:has_and_belongs_to_many),
+      DifferentPeopleList.reflect_on_association(:has_and_belongs_to_many)
+    )
+  end
+
+  def test_has_many_association_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal(
+      PeopleList.reflect_on_association(:has_many),
+      DifferentPeopleList.reflect_on_association(:has_many)
+    )
+  end
+
+  def test_belongs_to_association_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal(
+      PeopleList.reflect_on_association(:belongs_to),
+      DifferentPeopleList.reflect_on_association(:belongs_to)
+    )
+  end
+
+  def test_has_one_association_redefinition_reflections_should_differ_and_not_inherited
+    assert_not_equal(
+      PeopleList.reflect_on_association(:has_one),
+      DifferentPeopleList.reflect_on_association(:has_one)
+    )
+  end
+
+  def test_requires_symbol_argument
+    assert_raises ArgumentError do
+      Class.new(Post) do
+        belongs_to "author"
+      end
+    end
+  end
+end
+
+class GeneratedMethodsTest < ActiveRecord::TestCase
+  fixtures :developers, :computers, :posts, :comments
+  def test_association_methods_override_attribute_methods_of_same_name
+    assert_equal(developers(:david), computers(:workstation).developer)
+    # this next line will fail if the attribute methods module is generated lazily
+    # after the association methods module is generated
+    assert_equal(developers(:david), computers(:workstation).developer)
+    assert_equal(developers(:david).id, computers(:workstation)[:developer])
+  end
+
+  def test_model_method_overrides_association_method
+    assert_equal(comments(:greetings).body, posts(:welcome).first_comment)
+  end
+end
diff --git a/activerecord/test/cases/attribute_decorators_test.rb b/activerecord/test/cases/attribute_decorators_test.rb
new file mode 100644
index 0000000000..cbc2c4e5d7
--- /dev/null
+++ b/activerecord/test/cases/attribute_decorators_test.rb
@@ -0,0 +1,124 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class AttributeDecoratorsTest < ActiveRecord::TestCase
+    class Model < ActiveRecord::Base
+      self.table_name = 'attribute_decorators_model'
+    end
+
+    class StringDecorator < SimpleDelegator
+      def initialize(delegate, decoration = "decorated!")
+        @decoration = decoration
+        super(delegate)
+      end
+
+      def type_cast_from_user(value)
+        "#{super} #{@decoration}"
+      end
+
+      alias type_cast_from_database type_cast_from_user
+    end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      @connection.create_table :attribute_decorators_model, force: true do |t|
+        t.string :a_string
+      end
+    end
+
+    teardown do
+      return unless @connection
+      @connection.execute 'DROP TABLE IF EXISTS attribute_decorators_model'
+      Model.attribute_type_decorations.clear
+      Model.reset_column_information
+    end
+
+    test "attributes can be decorated" do
+      model = Model.new(a_string: 'Hello')
+      assert_equal 'Hello', model.a_string
+
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+
+      model = Model.new(a_string: 'Hello')
+      assert_equal 'Hello decorated!', model.a_string
+    end
+
+    test "decoration does not eagerly load existing columns" do
+      assert_no_queries do
+        Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      end
+    end
+
+    test "undecorated columns are not touched" do
+      Model.attribute :another_string, Type::String.new, default: 'something or other'
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+
+      assert_equal 'something or other', Model.new.another_string
+    end
+
+    test "decorators can be chained" do
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      Model.decorate_attribute_type(:a_string, :other) { |t| StringDecorator.new(t) }
+
+      model = Model.new(a_string: 'Hello!')
+
+      assert_equal 'Hello! decorated! decorated!', model.a_string
+    end
+
+    test "decoration of the same type multiple times is idempotent" do
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+
+      model = Model.new(a_string: 'Hello')
+      assert_equal 'Hello decorated!', model.a_string
+    end
+
+    test "decorations occur in order of declaration" do
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      Model.decorate_attribute_type(:a_string, :other) do |type|
+        StringDecorator.new(type, 'decorated again!')
+      end
+
+      model = Model.new(a_string: 'Hello!')
+
+      assert_equal 'Hello! decorated! decorated again!', model.a_string
+    end
+
+    test "decorating attributes does not modify parent classes" do
+      Model.attribute :another_string, Type::String.new, default: 'whatever'
+      Model.decorate_attribute_type(:a_string, :test) { |t| StringDecorator.new(t) }
+      child_class = Class.new(Model)
+      child_class.decorate_attribute_type(:another_string, :test) { |t| StringDecorator.new(t) }
+      child_class.decorate_attribute_type(:a_string, :other) { |t| StringDecorator.new(t) }
+
+      model = Model.new(a_string: 'Hello!')
+      child = child_class.new(a_string: 'Hello!')
+
+      assert_equal 'Hello! decorated!', model.a_string
+      assert_equal 'whatever', model.another_string
+      assert_equal 'Hello! decorated! decorated!', child.a_string
+      assert_equal 'whatever decorated!', child.another_string
+    end
+
+    class Multiplier < SimpleDelegator
+      def type_cast_from_user(value)
+        return if value.nil?
+        value * 2
+      end
+      alias type_cast_from_database type_cast_from_user
+    end
+
+    test "decorating with a proc" do
+      Model.attribute :an_int, Type::Integer.new
+      type_is_integer = proc { |_, type| type.type == :integer }
+      Model.decorate_matching_attribute_types type_is_integer, :multiplier do |type|
+        Multiplier.new(type)
+      end
+
+      model = Model.new(a_string: 'whatever', an_int: 1)
+
+      assert_equal 'whatever', model.a_string
+      assert_equal 2, model.an_int
+    end
+  end
+end
diff --git a/activerecord/test/cases/attribute_methods/read_test.rb b/activerecord/test/cases/attribute_methods/read_test.rb
new file mode 100644
index 0000000000..4741ee8799
--- /dev/null
+++ b/activerecord/test/cases/attribute_methods/read_test.rb
@@ -0,0 +1,59 @@
+require "cases/helper"
+require 'thread'
+
+module ActiveRecord
+  module AttributeMethods
+    class ReadTest < ActiveRecord::TestCase
+      class FakeColumn < Struct.new(:name)
+        def type; :integer; end
+      end
+
+      def setup
+        @klass = Class.new do
+          def self.superclass; Base; end
+          def self.base_class; self; end
+          def self.decorate_matching_attribute_types(*); end
+
+          include ActiveRecord::AttributeMethods
+
+          def self.column_names
+            %w{ one two three }
+          end
+
+          def self.primary_key
+          end
+
+          def self.columns
+            column_names.map { FakeColumn.new(name) }
+          end
+
+          def self.columns_hash
+            Hash[column_names.map { |name|
+              [name, FakeColumn.new(name)]
+            }]
+          end
+        end
+      end
+
+      def test_define_attribute_methods
+        instance = @klass.new
+
+        @klass.column_names.each do |name|
+          assert !instance.methods.map(&:to_s).include?(name)
+        end
+
+        @klass.define_attribute_methods
+
+        @klass.column_names.each do |name|
+          assert instance.methods.map(&:to_s).include?(name), "#{name} is not defined"
+        end
+      end
+
+      def test_attribute_methods_generated?
+        assert_not @klass.method_defined?(:one)
+        @klass.define_attribute_methods
+        assert @klass.method_defined?(:one)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
new file mode 100644
index 0000000000..ab67cf4085
--- /dev/null
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -0,0 +1,906 @@
+require "cases/helper"
+require 'models/minimalistic'
+require 'models/developer'
+require 'models/auto_id'
+require 'models/boolean'
+require 'models/computer'
+require 'models/topic'
+require 'models/company'
+require 'models/category'
+require 'models/reply'
+require 'models/contact'
+require 'models/keyboard'
+
+class AttributeMethodsTest < ActiveRecord::TestCase
+  include InTimeZone
+
+  fixtures :topics, :developers, :companies, :computers
+
+  def setup
+    @old_matchers = ActiveRecord::Base.send(:attribute_method_matchers).dup
+    @target = Class.new(ActiveRecord::Base)
+    @target.table_name = 'topics'
+  end
+
+  teardown do
+    ActiveRecord::Base.send(:attribute_method_matchers).clear
+    ActiveRecord::Base.send(:attribute_method_matchers).concat(@old_matchers)
+  end
+
+  def test_attribute_for_inspect
+    t = topics(:first)
+    t.title = "The First Topic Now Has A Title With\nNewlines And More Than 50 Characters"
+
+    assert_equal %("#{t.written_on.to_s(:db)}"), t.attribute_for_inspect(:written_on)
+    assert_equal '"The First Topic Now Has A Title With\nNewlines And ..."', t.attribute_for_inspect(:title)
+  end
+
+  def test_attribute_present
+    t = Topic.new
+    t.title = "hello there!"
+    t.written_on = Time.now
+    t.author_name = ""
+    assert t.attribute_present?("title")
+    assert t.attribute_present?("written_on")
+    assert !t.attribute_present?("content")
+    assert !t.attribute_present?("author_name")
+  end
+
+  def test_attribute_present_with_booleans
+    b1 = Boolean.new
+    b1.value = false
+    assert b1.attribute_present?(:value)
+
+    b2 = Boolean.new
+    b2.value = true
+    assert b2.attribute_present?(:value)
+
+    b3 = Boolean.new
+    assert !b3.attribute_present?(:value)
+
+    b4 = Boolean.new
+    b4.value = false
+    b4.save!
+    assert Boolean.find(b4.id).attribute_present?(:value)
+  end
+
+  def test_caching_nil_primary_key
+    klass = Class.new(Minimalistic)
+    klass.expects(:reset_primary_key).returns(nil).once
+    2.times { klass.primary_key }
+  end
+
+  def test_attribute_keys_on_new_instance
+    t = Topic.new
+    assert_equal nil, t.title, "The topics table has a title column, so it should be nil"
+    assert_raise(NoMethodError) { t.title2 }
+  end
+
+  def test_boolean_attributes
+    assert !Topic.find(1).approved?
+    assert Topic.find(2).approved?
+  end
+
+  def test_set_attributes
+    topic = Topic.find(1)
+    topic.attributes = { "title" => "Budget", "author_name" => "Jason" }
+    topic.save
+    assert_equal("Budget", topic.title)
+    assert_equal("Jason", topic.author_name)
+    assert_equal(topics(:first).author_email_address, Topic.find(1).author_email_address)
+  end
+
+  def test_set_attributes_without_hash
+    topic = Topic.new
+    assert_raise(ArgumentError) { topic.attributes = '' }
+  end
+
+  def test_integers_as_nil
+    test = AutoId.create('value' => '')
+    assert_nil AutoId.find(test.id).value
+  end
+
+  def test_set_attributes_with_block
+    topic = Topic.new do |t|
+      t.title       = "Budget"
+      t.author_name = "Jason"
+    end
+
+    assert_equal("Budget", topic.title)
+    assert_equal("Jason", topic.author_name)
+  end
+
+  def test_respond_to?
+    topic = Topic.find(1)
+    assert_respond_to topic, "title"
+    assert_respond_to topic, "title?"
+    assert_respond_to topic, "title="
+    assert_respond_to topic, :title
+    assert_respond_to topic, :title?
+    assert_respond_to topic, :title=
+    assert_respond_to topic, "author_name"
+    assert_respond_to topic, "attribute_names"
+    assert !topic.respond_to?("nothingness")
+    assert !topic.respond_to?(:nothingness)
+  end
+
+  def test_respond_to_with_custom_primary_key
+    keyboard = Keyboard.create
+    assert_not_nil keyboard.key_number
+    assert_equal keyboard.key_number, keyboard.id
+    assert keyboard.respond_to?('key_number')
+    assert keyboard.respond_to?('id')
+  end
+
+  def test_id_before_type_cast_with_custom_primary_key
+    keyboard = Keyboard.create
+    keyboard.key_number = '10'
+    assert_equal '10', keyboard.id_before_type_cast
+    assert_equal nil, keyboard.read_attribute_before_type_cast('id')
+    assert_equal '10', keyboard.read_attribute_before_type_cast('key_number')
+    assert_equal '10', keyboard.read_attribute_before_type_cast(:key_number)
+  end
+
+  # Syck calls respond_to? before actually calling initialize
+  def test_respond_to_with_allocated_object
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = 'topics'
+    end
+
+    topic = klass.allocate
+    assert !topic.respond_to?("nothingness")
+    assert !topic.respond_to?(:nothingness)
+    assert_respond_to topic, "title"
+    assert_respond_to topic, :title
+  end
+
+  # IRB inspects the return value of "MyModel.allocate".
+  def test_allocated_object_can_be_inspected
+    topic = Topic.allocate
+    assert_equal "#<Topic not initialized>", topic.inspect
+  end
+
+  def test_array_content
+    topic = Topic.new
+    topic.content = %w( one two three )
+    topic.save
+
+    assert_equal(%w( one two three ), Topic.find(topic.id).content)
+  end
+
+  def test_read_attributes_before_type_cast
+    category = Category.new({:name=>"Test category", :type => nil})
+    category_attrs = {"name"=>"Test category", "id" => nil, "type" => nil, "categorizations_count" => nil}
+    assert_equal category_attrs , category.attributes_before_type_cast
+  end
+
+  if current_adapter?(:MysqlAdapter)
+    def test_read_attributes_before_type_cast_on_boolean
+      bool = Boolean.create({ "value" => false })
+      if RUBY_PLATFORM =~ /java/
+        # JRuby will return the value before typecast as string
+        assert_equal "0", bool.reload.attributes_before_type_cast["value"]
+      else
+        assert_equal 0, bool.reload.attributes_before_type_cast["value"]
+      end
+    end
+  end
+
+  def test_read_attributes_before_type_cast_on_datetime
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+
+      record.written_on = "345643456"
+      assert_equal "345643456", record.written_on_before_type_cast
+      assert_equal nil, record.written_on
+
+      record.written_on = "2009-10-11 12:13:14"
+      assert_equal "2009-10-11 12:13:14", record.written_on_before_type_cast
+      assert_equal Time.zone.parse("2009-10-11 12:13:14"), record.written_on
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+    end
+  end
+
+  def test_read_attributes_after_type_cast_on_datetime
+    tz = "Pacific Time (US & Canada)"
+
+    in_time_zone tz do
+      record = @target.new
+
+      date_string = "2011-03-24"
+      time        = Time.zone.parse date_string
+
+      record.written_on = date_string
+      assert_equal date_string, record.written_on_before_type_cast
+      assert_equal time, record.written_on
+      assert_equal ActiveSupport::TimeZone[tz], record.written_on.time_zone
+
+      record.save
+      record.reload
+
+      assert_equal time, record.written_on
+    end
+  end
+
+  def test_hash_content
+    topic = Topic.new
+    topic.content = { "one" => 1, "two" => 2 }
+    topic.save
+
+    assert_equal 2, Topic.find(topic.id).content["two"]
+
+    topic.content_will_change!
+    topic.content["three"] = 3
+    topic.save
+
+    assert_equal 3, Topic.find(topic.id).content["three"]
+  end
+
+  def test_update_array_content
+    topic = Topic.new
+    topic.content = %w( one two three )
+
+    topic.content.push "four"
+    assert_equal(%w( one two three four ), topic.content)
+
+    topic.save
+
+    topic = Topic.find(topic.id)
+    topic.content << "five"
+    assert_equal(%w( one two three four five ), topic.content)
+  end
+
+  def test_case_sensitive_attributes_hash
+    # DB2 is not case-sensitive
+    return true if current_adapter?(:DB2Adapter)
+
+    assert_equal @loaded_fixtures['computers']['workstation'].to_hash, Computer.first.attributes
+  end
+
+  def test_attributes_without_primary_key
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = 'developers_projects'
+    end
+
+    assert_equal klass.column_names, klass.new.attributes.keys
+    assert_not klass.new.attributes.key?('id')
+  end
+
+  def test_hashes_not_mangled
+    new_topic = { :title => "New Topic" }
+    new_topic_values = { :title => "AnotherTopic" }
+
+    topic = Topic.new(new_topic)
+    assert_equal new_topic[:title], topic.title
+
+    topic.attributes= new_topic_values
+    assert_equal new_topic_values[:title], topic.title
+  end
+
+  def test_create_through_factory
+    topic = Topic.create("title" => "New Topic")
+    topicReloaded = Topic.find(topic.id)
+    assert_equal(topic, topicReloaded)
+  end
+
+  def test_write_attribute
+    topic = Topic.new
+    topic.send(:write_attribute, :title, "Still another topic")
+    assert_equal "Still another topic", topic.title
+
+    topic[:title] = "Still another topic: part 2"
+    assert_equal "Still another topic: part 2", topic.title
+
+    topic.send(:write_attribute, "title", "Still another topic: part 3")
+    assert_equal "Still another topic: part 3", topic.title
+
+    topic["title"] = "Still another topic: part 4"
+    assert_equal "Still another topic: part 4", topic.title
+  end
+
+  def test_read_attribute
+    topic = Topic.new
+    topic.title = "Don't change the topic"
+    assert_equal "Don't change the topic", topic.read_attribute("title")
+    assert_equal "Don't change the topic", topic["title"]
+
+    assert_equal "Don't change the topic", topic.read_attribute(:title)
+    assert_equal "Don't change the topic", topic[:title]
+  end
+
+  def test_read_attribute_raises_missing_attribute_error_when_not_exists
+    computer = Computer.select('id').first
+    assert_raises(ActiveModel::MissingAttributeError) { computer[:developer] }
+    assert_raises(ActiveModel::MissingAttributeError) { computer[:extendedWarranty] }
+    assert_raises(ActiveModel::MissingAttributeError) { computer[:no_column_exists] = 'Hello!' }
+    assert_nothing_raised { computer[:developer] = 'Hello!' }
+  end
+
+  def test_read_attribute_when_false
+    topic = topics(:first)
+    topic.approved = false
+    assert !topic.approved?, "approved should be false"
+    topic.approved = "false"
+    assert !topic.approved?, "approved should be false"
+  end
+
+  def test_read_attribute_when_true
+    topic = topics(:first)
+    topic.approved = true
+    assert topic.approved?, "approved should be true"
+    topic.approved = "true"
+    assert topic.approved?, "approved should be true"
+  end
+
+  def test_read_write_boolean_attribute
+    topic = Topic.new
+    topic.approved = "false"
+    assert !topic.approved?, "approved should be false"
+
+    topic.approved = "false"
+    assert !topic.approved?, "approved should be false"
+
+    topic.approved = "true"
+    assert topic.approved?, "approved should be true"
+
+    topic.approved = "true"
+    assert topic.approved?, "approved should be true"
+  end
+
+  def test_overridden_write_attribute
+    topic = Topic.new
+    def topic.write_attribute(attr_name, value)
+      super(attr_name, value.downcase)
+    end
+
+    topic.send(:write_attribute, :title, "Yet another topic")
+    assert_equal "yet another topic", topic.title
+
+    topic[:title] = "Yet another topic: part 2"
+    assert_equal "yet another topic: part 2", topic.title
+
+    topic.send(:write_attribute, "title", "Yet another topic: part 3")
+    assert_equal "yet another topic: part 3", topic.title
+
+    topic["title"] = "Yet another topic: part 4"
+    assert_equal "yet another topic: part 4", topic.title
+  end
+
+  def test_overridden_read_attribute
+    topic = Topic.new
+    topic.title = "Stop changing the topic"
+    def topic.read_attribute(attr_name)
+      super(attr_name).upcase
+    end
+
+    assert_equal "STOP CHANGING THE TOPIC", topic.read_attribute("title")
+    assert_equal "STOP CHANGING THE TOPIC", topic["title"]
+
+    assert_equal "STOP CHANGING THE TOPIC", topic.read_attribute(:title)
+    assert_equal "STOP CHANGING THE TOPIC", topic[:title]
+  end
+
+  def test_read_overridden_attribute
+    topic = Topic.new(:title => 'a')
+    def topic.title() 'b' end
+    assert_equal 'a', topic[:title]
+  end
+
+  def test_query_attribute_string
+    [nil, "", " "].each do |value|
+      assert_equal false, Topic.new(:author_name => value).author_name?
+    end
+
+    assert_equal true, Topic.new(:author_name => "Name").author_name?
+  end
+
+  def test_query_attribute_number
+    [nil, 0, "0"].each do |value|
+      assert_equal false, Developer.new(:salary => value).salary?
+    end
+
+    assert_equal true, Developer.new(:salary => 1).salary?
+    assert_equal true, Developer.new(:salary => "1").salary?
+  end
+
+  def test_query_attribute_boolean
+    [nil, "", false, "false", "f", 0].each do |value|
+      assert_equal false, Topic.new(:approved => value).approved?
+    end
+
+    [true, "true", "1", 1].each do |value|
+      assert_equal true, Topic.new(:approved => value).approved?
+    end
+  end
+
+  def test_query_attribute_with_custom_fields
+    object = Company.find_by_sql(<<-SQL).first
+      SELECT c1.*, c2.type as string_value, c2.rating as int_value
+        FROM companies c1, companies c2
+       WHERE c1.firm_id = c2.id
+         AND c1.id = 2
+    SQL
+
+    assert_equal "Firm", object.string_value
+    assert object.string_value?
+
+    object.string_value = "  "
+    assert !object.string_value?
+
+    assert_equal 1, object.int_value.to_i
+    assert object.int_value?
+
+    object.int_value = "0"
+    assert !object.int_value?
+  end
+
+  def test_non_attribute_access_and_assignment
+    topic = Topic.new
+    assert !topic.respond_to?("mumbo")
+    assert_raise(NoMethodError) { topic.mumbo }
+    assert_raise(NoMethodError) { topic.mumbo = 5 }
+  end
+
+  def test_undeclared_attribute_method_does_not_affect_respond_to_and_method_missing
+    topic = @target.new(:title => 'Budget')
+    assert topic.respond_to?('title')
+    assert_equal 'Budget', topic.title
+    assert !topic.respond_to?('title_hello_world')
+    assert_raise(NoMethodError) { topic.title_hello_world }
+  end
+
+  def test_declared_prefixed_attribute_method_affects_respond_to_and_method_missing
+    topic = @target.new(:title => 'Budget')
+    %w(default_ title_).each do |prefix|
+      @target.class_eval "def #{prefix}attribute(*args) args end"
+      @target.attribute_method_prefix prefix
+
+      meth = "#{prefix}title"
+      assert topic.respond_to?(meth)
+      assert_equal ['title'], topic.send(meth)
+      assert_equal ['title', 'a'], topic.send(meth, 'a')
+      assert_equal ['title', 1, 2, 3], topic.send(meth, 1, 2, 3)
+    end
+  end
+
+  def test_declared_suffixed_attribute_method_affects_respond_to_and_method_missing
+    %w(_default _title_default _it! _candidate= able?).each do |suffix|
+      @target.class_eval "def attribute#{suffix}(*args) args end"
+      @target.attribute_method_suffix suffix
+      topic = @target.new(:title => 'Budget')
+
+      meth = "title#{suffix}"
+      assert topic.respond_to?(meth)
+      assert_equal ['title'], topic.send(meth)
+      assert_equal ['title', 'a'], topic.send(meth, 'a')
+      assert_equal ['title', 1, 2, 3], topic.send(meth, 1, 2, 3)
+    end
+  end
+
+  def test_declared_affixed_attribute_method_affects_respond_to_and_method_missing
+    [['mark_', '_for_update'], ['reset_', '!'], ['default_', '_value?']].each do |prefix, suffix|
+      @target.class_eval "def #{prefix}attribute#{suffix}(*args) args end"
+      @target.attribute_method_affix({ :prefix => prefix, :suffix => suffix })
+      topic = @target.new(:title => 'Budget')
+
+      meth = "#{prefix}title#{suffix}"
+      assert topic.respond_to?(meth)
+      assert_equal ['title'], topic.send(meth)
+      assert_equal ['title', 'a'], topic.send(meth, 'a')
+      assert_equal ['title', 1, 2, 3], topic.send(meth, 1, 2, 3)
+    end
+  end
+
+  def test_should_unserialize_attributes_for_frozen_records
+    myobj = {:value1 => :value2}
+    topic = Topic.create("content" => myobj)
+    topic.freeze
+    assert_equal myobj, topic.content
+  end
+
+  def test_typecast_attribute_from_select_to_false
+    Topic.create(:title => 'Budget')
+    # Oracle does not support boolean expressions in SELECT
+    if current_adapter?(:OracleAdapter)
+      topic = Topic.all.merge!(:select => "topics.*, 0 as is_test").first
+    else
+      topic = Topic.all.merge!(:select => "topics.*, 1=2 as is_test").first
+    end
+    assert !topic.is_test?
+  end
+
+  def test_typecast_attribute_from_select_to_true
+    Topic.create(:title => 'Budget')
+    # Oracle does not support boolean expressions in SELECT
+    if current_adapter?(:OracleAdapter)
+      topic = Topic.all.merge!(:select => "topics.*, 1 as is_test").first
+    else
+      topic = Topic.all.merge!(:select => "topics.*, 2=2 as is_test").first
+    end
+    assert topic.is_test?
+  end
+
+  def test_raises_dangerous_attribute_error_when_defining_activerecord_method_in_model
+    %w(save create_or_update).each do |method|
+      klass = Class.new ActiveRecord::Base
+      klass.class_eval "def #{method}() 'defined #{method}' end"
+      assert_raise ActiveRecord::DangerousAttributeError do
+        klass.instance_method_already_implemented?(method)
+      end
+    end
+  end
+
+  def test_deprecated_cache_attributes
+    assert_deprecated do
+      Topic.cache_attributes :replies_count
+    end
+
+    assert_deprecated do
+      Topic.cached_attributes
+    end
+
+    assert_deprecated do
+      Topic.cache_attribute? :replies_count
+    end
+  end
+
+  def test_converted_values_are_returned_after_assignment
+    developer = Developer.new(name: 1337, salary: "50000")
+
+    assert_equal "50000", developer.salary_before_type_cast
+    assert_equal 1337, developer.name_before_type_cast
+
+    assert_equal 50000, developer.salary
+    assert_equal "1337", developer.name
+
+    developer.save!
+
+    assert_equal "50000", developer.salary_before_type_cast
+    assert_equal 1337, developer.name_before_type_cast
+
+    assert_equal 50000, developer.salary
+    assert_equal "1337", developer.name
+  end
+
+  def test_write_nil_to_time_attributes
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+      record.written_on = nil
+      assert_nil record.written_on
+    end
+  end
+
+  def test_write_time_to_date_attributes
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.new
+      record.last_read = Time.utc(2010, 1, 1, 10)
+      assert_equal Date.civil(2010, 1, 1), record.last_read
+    end
+  end
+
+  def test_time_attributes_are_retrieved_in_current_time_zone
+    in_time_zone "Pacific Time (US & Canada)" do
+      utc_time = Time.utc(2008, 1, 1)
+      record   = @target.new
+      record[:written_on] = utc_time
+      assert_equal utc_time, record.written_on # record.written on is equal to (i.e., simultaneous with) utc_time
+      assert_kind_of ActiveSupport::TimeWithZone, record.written_on # but is a TimeWithZone
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone # and is in the current Time.zone
+      assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time # and represents time values adjusted accordingly
+    end
+  end
+
+  def test_setting_time_zone_aware_attribute_to_utc
+    in_time_zone "Pacific Time (US & Canada)" do
+      utc_time = Time.utc(2008, 1, 1)
+      record   = @target.new
+      record.written_on = utc_time
+      assert_equal utc_time, record.written_on
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+      assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time
+    end
+  end
+
+  def test_setting_time_zone_aware_attribute_in_other_time_zone
+    utc_time = Time.utc(2008, 1, 1)
+    cst_time = utc_time.in_time_zone("Central Time (US & Canada)")
+    in_time_zone "Pacific Time (US & Canada)" do
+      record   = @target.new
+      record.written_on = cst_time
+      assert_equal utc_time, record.written_on
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+      assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time
+    end
+  end
+
+  def test_setting_time_zone_aware_read_attribute
+    utc_time = Time.utc(2008, 1, 1)
+    cst_time = utc_time.in_time_zone("Central Time (US & Canada)")
+    in_time_zone "Pacific Time (US & Canada)" do
+      record = @target.create(:written_on => cst_time).reload
+      assert_equal utc_time, record[:written_on]
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record[:written_on].time_zone
+      assert_equal Time.utc(2007, 12, 31, 16), record[:written_on].time
+    end
+  end
+
+  def test_setting_time_zone_aware_attribute_with_string
+    utc_time = Time.utc(2008, 1, 1)
+    (-11..13).each do |timezone_offset|
+      time_string = utc_time.in_time_zone(timezone_offset).to_s
+      in_time_zone "Pacific Time (US & Canada)" do
+        record   = @target.new
+        record.written_on = time_string
+        assert_equal Time.zone.parse(time_string), record.written_on
+        assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+        assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time
+      end
+    end
+  end
+
+  def test_time_zone_aware_attribute_saved
+    in_time_zone 1 do
+      record = @target.create(:written_on => '2012-02-20 10:00')
+
+      record.written_on = '2012-02-20 09:00'
+      record.save
+      assert_equal Time.zone.local(2012, 02, 20, 9), record.reload.written_on
+    end
+  end
+
+  def test_setting_time_zone_aware_attribute_to_blank_string_returns_nil
+    in_time_zone "Pacific Time (US & Canada)" do
+      record   = @target.new
+      record.written_on = ' '
+      assert_nil record.written_on
+      assert_nil record[:written_on]
+    end
+  end
+
+  def test_setting_time_zone_aware_attribute_interprets_time_zone_unaware_string_in_time_zone
+    time_string = 'Tue Jan 01 00:00:00 2008'
+    (-11..13).each do |timezone_offset|
+      in_time_zone timezone_offset do
+        record   = @target.new
+        record.written_on = time_string
+        assert_equal Time.zone.parse(time_string), record.written_on
+        assert_equal ActiveSupport::TimeZone[timezone_offset], record.written_on.time_zone
+        assert_equal Time.utc(2008, 1, 1), record.written_on.time
+      end
+    end
+  end
+
+  def test_setting_time_zone_aware_attribute_in_current_time_zone
+    utc_time = Time.utc(2008, 1, 1)
+    in_time_zone "Pacific Time (US & Canada)" do
+      record   = @target.new
+      record.written_on = utc_time.in_time_zone
+      assert_equal utc_time, record.written_on
+      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"], record.written_on.time_zone
+      assert_equal Time.utc(2007, 12, 31, 16), record.written_on.time
+    end
+  end
+
+  def test_setting_time_zone_conversion_for_attributes_should_write_value_on_class_variable
+    Topic.skip_time_zone_conversion_for_attributes = [:field_a]
+    Minimalistic.skip_time_zone_conversion_for_attributes = [:field_b]
+
+    assert_equal [:field_a], Topic.skip_time_zone_conversion_for_attributes
+    assert_equal [:field_b], Minimalistic.skip_time_zone_conversion_for_attributes
+  end
+
+  def test_read_attributes_respect_access_control
+    privatize("title")
+
+    topic = @target.new(:title => "The pros and cons of programming naked.")
+    assert !topic.respond_to?(:title)
+    exception = assert_raise(NoMethodError) { topic.title }
+    assert exception.message.include?("private method")
+    assert_equal "I'm private", topic.send(:title)
+  end
+
+  def test_write_attributes_respect_access_control
+    privatize("title=(value)")
+
+    topic = @target.new
+    assert !topic.respond_to?(:title=)
+    exception = assert_raise(NoMethodError) { topic.title = "Pants"}
+    assert exception.message.include?("private method")
+    topic.send(:title=, "Very large pants")
+  end
+
+  def test_question_attributes_respect_access_control
+    privatize("title?")
+
+    topic = @target.new(:title => "Isaac Newton's pants")
+    assert !topic.respond_to?(:title?)
+    exception = assert_raise(NoMethodError) { topic.title? }
+    assert exception.message.include?("private method")
+    assert topic.send(:title?)
+  end
+
+  def test_bulk_update_respects_access_control
+    privatize("title=(value)")
+
+    assert_raise(ActiveRecord::UnknownAttributeError) { @target.new(:title => "Rants about pants") }
+    assert_raise(ActiveRecord::UnknownAttributeError) { @target.new.attributes = { :title => "Ants in pants" } }
+  end
+
+  def test_bulk_update_raise_unknown_attribute_errro
+    error = assert_raises(ActiveRecord::UnknownAttributeError) {
+      @target.new(:hello => "world")
+    }
+    assert @target, error.record
+    assert "hello", error.attribute
+    assert "unknown attribute: hello", error.message
+  end
+
+  def test_methods_override_in_multi_level_subclass
+    klass = Class.new(Developer) do
+      def name
+        "dev:#{read_attribute(:name)}"
+      end
+    end
+
+    2.times { klass = Class.new klass }
+    dev = klass.new(name: 'arthurnn')
+    dev.save!
+    assert_equal 'dev:arthurnn', dev.reload.name
+  end
+
+  def test_global_methods_are_overwritten
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = 'computers'
+    end
+
+    assert !klass.instance_method_already_implemented?(:system)
+    computer = klass.new
+    assert_nil computer.system
+  end
+
+  def test_global_methods_are_overwritte_when_subclassing
+    klass = Class.new(ActiveRecord::Base) { self.abstract_class = true }
+
+    subklass = Class.new(klass) do
+      self.table_name = 'computers'
+    end
+
+    assert !klass.instance_method_already_implemented?(:system)
+    assert !subklass.instance_method_already_implemented?(:system)
+    computer = subklass.new
+    assert_nil computer.system
+  end
+
+  def test_instance_method_should_be_defined_on_the_base_class
+    subklass = Class.new(Topic)
+
+    Topic.define_attribute_methods
+
+    instance = subklass.new
+    instance.id = 5
+    assert_equal 5, instance.id
+    assert subklass.method_defined?(:id), "subklass is missing id method"
+
+    Topic.undefine_attribute_methods
+
+    assert_equal 5, instance.id
+    assert subklass.method_defined?(:id), "subklass is missing id method"
+  end
+
+  def test_read_attribute_with_nil_should_not_asplode
+    assert_equal nil, Topic.new.read_attribute(nil)
+  end
+
+  # If B < A, and A defines an accessor for 'foo', we don't want to override
+  # that by defining a 'foo' method in the generated methods module for B.
+  # (That module will be inserted between the two, e.g. [B, <GeneratedAttributes>, A].)
+  def test_inherited_custom_accessors
+    klass = new_topic_like_ar_class do
+      self.abstract_class = true
+      def title; "omg"; end
+      def title=(val); self.author_name = val; end
+    end
+    subklass = Class.new(klass)
+    [klass, subklass].each(&:define_attribute_methods)
+
+    topic = subklass.find(1)
+    assert_equal "omg", topic.title
+
+    topic.title = "lol"
+    assert_equal "lol", topic.author_name
+  end
+
+  def test_on_the_fly_super_invokable_generated_attribute_methods_via_method_missing
+    klass = new_topic_like_ar_class do
+      def title
+        super + '!'
+      end
+    end
+
+    real_topic = topics(:first)
+    assert_equal real_topic.title + '!', klass.find(real_topic.id).title
+  end
+
+  def test_on_the_fly_super_invokable_generated_predicate_attribute_methods_via_method_missing
+    klass = new_topic_like_ar_class do
+      def title?
+        !super
+      end
+    end
+
+    real_topic = topics(:first)
+    assert_equal !real_topic.title?, klass.find(real_topic.id).title?
+  end
+
+  def test_calling_super_when_parent_does_not_define_method_raises_error
+    klass = new_topic_like_ar_class do
+      def some_method_that_is_not_on_super
+        super
+      end
+    end
+
+    assert_raise(NoMethodError) do
+      klass.new.some_method_that_is_not_on_super
+    end
+  end
+
+  def test_attribute_method?
+    assert @target.attribute_method?(:title)
+    assert @target.attribute_method?(:title=)
+    assert_not @target.attribute_method?(:wibble)
+  end
+
+  def test_attribute_method_returns_false_if_table_does_not_exist
+    @target.table_name = 'wibble'
+    assert_not @target.attribute_method?(:title)
+  end
+
+  def test_attribute_names_on_new_record
+    model = @target.new
+
+    assert_equal @target.column_names, model.attribute_names
+  end
+
+  def test_attribute_names_on_queried_record
+    model = @target.last!
+
+    assert_equal @target.column_names, model.attribute_names
+  end
+
+  def test_attribute_names_with_custom_select
+    model = @target.select('id').last!
+
+    assert_equal ['id'], model.attribute_names
+    # Sanity check, make sure other columns exist
+    assert_not_equal ['id'], @target.column_names
+  end
+
+  private
+
+  def new_topic_like_ar_class(&block)
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = 'topics'
+      class_eval(&block)
+    end
+
+    assert_empty klass.generated_attribute_methods.instance_methods(false)
+    klass
+  end
+
+  def cached_columns
+    Topic.columns.map(&:name)
+  end
+
+  def time_related_columns_on_topic
+    Topic.columns.select { |c| [:time, :date, :datetime, :timestamp].include?(c.type) }
+  end
+
+  def privatize(method_signature)
+    @target.class_eval(<<-private_method, __FILE__, __LINE__ + 1)
+      private
+      def #{method_signature}
+        "I'm private"
+      end
+    private_method
+  end
+end
diff --git a/activerecord/test/cases/attribute_set_test.rb b/activerecord/test/cases/attribute_set_test.rb
new file mode 100644
index 0000000000..dc20c3c676
--- /dev/null
+++ b/activerecord/test/cases/attribute_set_test.rb
@@ -0,0 +1,165 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class AttributeSetTest < ActiveRecord::TestCase
+    test "building a new set from raw attributes" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2.2, attributes[:bar].value
+      assert_equal :foo, attributes[:foo].name
+      assert_equal :bar, attributes[:bar].name
+    end
+
+    test "building with custom types" do
+      builder = AttributeSet::Builder.new(foo: Type::Float.new)
+      attributes = builder.build_from_database({ foo: '3.3', bar: '4.4' }, { bar: Type::Integer.new })
+
+      assert_equal 3.3, attributes[:foo].value
+      assert_equal 4, attributes[:bar].value
+    end
+
+    test "[] returns a null object" do
+      builder = AttributeSet::Builder.new(foo: Type::Float.new)
+      attributes = builder.build_from_database(foo: '3.3')
+
+      assert_equal '3.3', attributes[:foo].value_before_type_cast
+      assert_equal nil, attributes[:bar].value_before_type_cast
+      assert_equal :bar, attributes[:bar].name
+    end
+
+    test "duping creates a new hash and dups each attribute" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::String.new)
+      attributes = builder.build_from_database(foo: 1, bar: 'foo')
+
+      # Ensure the type cast value is cached
+      attributes[:foo].value
+      attributes[:bar].value
+
+      duped = attributes.dup
+      duped.write_from_database(:foo, 2)
+      duped[:bar].value << 'bar'
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2, duped[:foo].value
+      assert_equal 'foo', attributes[:bar].value
+      assert_equal 'foobar', duped[:bar].value
+    end
+
+    test "freezing cloned set does not freeze original" do
+      attributes = AttributeSet.new({})
+      clone = attributes.clone
+
+      clone.freeze
+
+      assert clone.frozen?
+      assert_not attributes.frozen?
+    end
+
+    test "to_hash returns a hash of the type cast values" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
+
+      assert_equal({ foo: 1, bar: 2.2 }, attributes.to_hash)
+      assert_equal({ foo: 1, bar: 2.2 }, attributes.to_h)
+    end
+
+    test "values_before_type_cast" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
+      attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
+
+      assert_equal({ foo: '1.1', bar: '2.2' }, attributes.values_before_type_cast)
+    end
+
+    test "known columns are built with uninitialized attributes" do
+      attributes = attributes_with_uninitialized_key
+      assert attributes[:foo].initialized?
+      assert_not attributes[:bar].initialized?
+    end
+
+    test "uninitialized attributes are not included in the attributes hash" do
+      attributes = attributes_with_uninitialized_key
+      assert_equal({ foo: 1 }, attributes.to_hash)
+    end
+
+    test "uninitialized attributes are not included in keys" do
+      attributes = attributes_with_uninitialized_key
+      assert_equal [:foo], attributes.keys
+    end
+
+    test "uninitialized attributes return false for key?" do
+      attributes = attributes_with_uninitialized_key
+      assert attributes.key?(:foo)
+      assert_not attributes.key?(:bar)
+    end
+
+    test "unknown attributes return false for key?" do
+      attributes = attributes_with_uninitialized_key
+      assert_not attributes.key?(:wibble)
+    end
+
+    test "fetch_value returns the value for the given initialized attribute" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
+
+      assert_equal 1, attributes.fetch_value(:foo)
+      assert_equal 2.2, attributes.fetch_value(:bar)
+    end
+
+    test "fetch_value returns nil for unknown attributes" do
+      attributes = attributes_with_uninitialized_key
+      assert_nil attributes.fetch_value(:wibble)
+    end
+
+    test "fetch_value uses the given block for uninitialized attributes" do
+      attributes = attributes_with_uninitialized_key
+      value = attributes.fetch_value(:bar) { |n| n.to_s + '!' }
+      assert_equal 'bar!', value
+    end
+
+    test "fetch_value returns nil for uninitialized attributes if no block is given" do
+      attributes = attributes_with_uninitialized_key
+      assert_nil attributes.fetch_value(:bar)
+    end
+
+    class MyType
+      def type_cast_from_user(value)
+        return if value.nil?
+        value + " from user"
+      end
+
+      def type_cast_from_database(value)
+        return if value.nil?
+        value + " from database"
+      end
+    end
+
+    test "write_from_database sets the attribute with database typecasting" do
+      builder = AttributeSet::Builder.new(foo: MyType.new)
+      attributes = builder.build_from_database
+
+      assert_nil attributes.fetch_value(:foo)
+
+      attributes.write_from_database(:foo, "value")
+
+      assert_equal "value from database", attributes.fetch_value(:foo)
+    end
+
+    test "write_from_user sets the attribute with user typecasting" do
+      builder = AttributeSet::Builder.new(foo: MyType.new)
+      attributes = builder.build_from_database
+
+      assert_nil attributes.fetch_value(:foo)
+
+      attributes.write_from_user(:foo, "value")
+
+      assert_equal "value from user", attributes.fetch_value(:foo)
+    end
+
+    def attributes_with_uninitialized_key
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      builder.build_from_database(foo: '1.1')
+    end
+  end
+end
diff --git a/activerecord/test/cases/attribute_test.rb b/activerecord/test/cases/attribute_test.rb
new file mode 100644
index 0000000000..91f6aee931
--- /dev/null
+++ b/activerecord/test/cases/attribute_test.rb
@@ -0,0 +1,142 @@
+require 'cases/helper'
+require 'minitest/mock'
+
+module ActiveRecord
+  class AttributeTest < ActiveRecord::TestCase
+    setup do
+      @type = Minitest::Mock.new
+    end
+
+    teardown do
+      assert @type.verify
+    end
+
+    test "from_database + read type casts from database" do
+      @type.expect(:type_cast_from_database, 'type cast from database', ['a value'])
+      attribute = Attribute.from_database(nil, 'a value', @type)
+
+      type_cast_value = attribute.value
+
+      assert_equal 'type cast from database', type_cast_value
+    end
+
+    test "from_user + read type casts from user" do
+      @type.expect(:type_cast_from_user, 'type cast from user', ['a value'])
+      attribute = Attribute.from_user(nil, 'a value', @type)
+
+      type_cast_value = attribute.value
+
+      assert_equal 'type cast from user', type_cast_value
+    end
+
+    test "reading memoizes the value" do
+      @type.expect(:type_cast_from_database, 'from the database', ['whatever'])
+      attribute = Attribute.from_database(nil, 'whatever', @type)
+
+      type_cast_value = attribute.value
+      second_read = attribute.value
+
+      assert_equal 'from the database', type_cast_value
+      assert_same type_cast_value, second_read
+    end
+
+    test "reading memoizes falsy values" do
+      @type.expect(:type_cast_from_database, false, ['whatever'])
+      attribute = Attribute.from_database(nil, 'whatever', @type)
+
+      attribute.value
+      attribute.value
+    end
+
+    test "read_before_typecast returns the given value" do
+      attribute = Attribute.from_database(nil, 'raw value', @type)
+
+      raw_value = attribute.value_before_type_cast
+
+      assert_equal 'raw value', raw_value
+    end
+
+    test "from_database + read_for_database type casts to and from database" do
+      @type.expect(:type_cast_from_database, 'read from database', ['whatever'])
+      @type.expect(:type_cast_for_database, 'ready for database', ['read from database'])
+      attribute = Attribute.from_database(nil, 'whatever', @type)
+
+      type_cast_for_database = attribute.value_for_database
+
+      assert_equal 'ready for database', type_cast_for_database
+    end
+
+    test "from_user + read_for_database type casts from the user to the database" do
+      @type.expect(:type_cast_from_user, 'read from user', ['whatever'])
+      @type.expect(:type_cast_for_database, 'ready for database', ['read from user'])
+      attribute = Attribute.from_user(nil, 'whatever', @type)
+
+      type_cast_for_database = attribute.value_for_database
+
+      assert_equal 'ready for database', type_cast_for_database
+    end
+
+    test "duping dups the value" do
+      @type.expect(:type_cast_from_database, 'type cast', ['a value'])
+      attribute = Attribute.from_database(nil, 'a value', @type)
+
+      value_from_orig = attribute.value
+      value_from_clone = attribute.dup.value
+      value_from_orig << ' foo'
+
+      assert_equal 'type cast foo', value_from_orig
+      assert_equal 'type cast', value_from_clone
+    end
+
+    test "duping does not dup the value if it is not dupable" do
+      @type.expect(:type_cast_from_database, false, ['a value'])
+      attribute = Attribute.from_database(nil, 'a value', @type)
+
+      assert_same attribute.value, attribute.dup.value
+    end
+
+    test "duping does not eagerly type cast if we have not yet type cast" do
+      attribute = Attribute.from_database(nil, 'a value', @type)
+      attribute.dup
+    end
+
+    class MyType
+      def type_cast_from_user(value)
+        value + " from user"
+      end
+
+      def type_cast_from_database(value)
+        value + " from database"
+      end
+    end
+
+    test "with_value_from_user returns a new attribute with the value from the user" do
+      old = Attribute.from_database(nil, "old", MyType.new)
+      new = old.with_value_from_user("new")
+
+      assert_equal "old from database", old.value
+      assert_equal "new from user", new.value
+    end
+
+    test "with_value_from_database returns a new attribute with the value from the database" do
+      old = Attribute.from_user(nil, "old", MyType.new)
+      new = old.with_value_from_database("new")
+
+      assert_equal "old from user", old.value
+      assert_equal "new from database", new.value
+    end
+
+    test "uninitialized attributes yield their name if a block is given to value" do
+      block = proc { |name| name.to_s + "!" }
+      foo = Attribute.uninitialized(:foo, nil)
+      bar = Attribute.uninitialized(:bar, nil)
+
+      assert_equal "foo!", foo.value(&block)
+      assert_equal "bar!", bar.value(&block)
+    end
+
+    test "uninitialized attributes have no value" do
+      assert_nil Attribute.uninitialized(:foo, nil).value
+    end
+  end
+end
diff --git a/activerecord/test/cases/attributes_test.rb b/activerecord/test/cases/attributes_test.rb
new file mode 100644
index 0000000000..79ef0502cb
--- /dev/null
+++ b/activerecord/test/cases/attributes_test.rb
@@ -0,0 +1,111 @@
+require 'cases/helper'
+
+class OverloadedType < ActiveRecord::Base
+  attribute :overloaded_float, Type::Integer.new
+  attribute :overloaded_string_with_limit, Type::String.new(limit: 50)
+  attribute :non_existent_decimal, Type::Decimal.new
+  attribute :string_with_default, Type::String.new, default: 'the overloaded default'
+end
+
+class ChildOfOverloadedType < OverloadedType
+end
+
+class GrandchildOfOverloadedType < ChildOfOverloadedType
+  attribute :overloaded_float, Type::Float.new
+end
+
+class UnoverloadedType < ActiveRecord::Base
+  self.table_name = 'overloaded_types'
+end
+
+module ActiveRecord
+  class CustomPropertiesTest < ActiveRecord::TestCase
+    def test_overloading_types
+      data = OverloadedType.new
+
+      data.overloaded_float = "1.1"
+      data.unoverloaded_float = "1.1"
+
+      assert_equal 1, data.overloaded_float
+      assert_equal 1.1, data.unoverloaded_float
+    end
+
+    def test_overloaded_properties_save
+      data = OverloadedType.new
+
+      data.overloaded_float = "2.2"
+      data.save!
+      data.reload
+
+      assert_equal 2, data.overloaded_float
+      assert_kind_of Fixnum, OverloadedType.last.overloaded_float
+      assert_equal 2.0, UnoverloadedType.last.overloaded_float
+      assert_kind_of Float, UnoverloadedType.last.overloaded_float
+    end
+
+    def test_properties_assigned_in_constructor
+      data = OverloadedType.new(overloaded_float: '3.3')
+
+      assert_equal 3, data.overloaded_float
+    end
+
+    def test_overloaded_properties_with_limit
+      assert_equal 50, OverloadedType.columns_hash['overloaded_string_with_limit'].limit
+      assert_equal 255, UnoverloadedType.columns_hash['overloaded_string_with_limit'].limit
+    end
+
+    def test_nonexistent_attribute
+      data = OverloadedType.new(non_existent_decimal: 1)
+
+      assert_equal BigDecimal.new(1), data.non_existent_decimal
+      assert_raise ActiveRecord::UnknownAttributeError do
+        UnoverloadedType.new(non_existent_decimal: 1)
+      end
+    end
+
+    def test_changing_defaults
+      data = OverloadedType.new
+      unoverloaded_data = UnoverloadedType.new
+
+      assert_equal 'the overloaded default', data.string_with_default
+      assert_equal 'the original default', unoverloaded_data.string_with_default
+    end
+
+    def test_children_inherit_custom_properties
+      data = ChildOfOverloadedType.new(overloaded_float: '4.4')
+
+      assert_equal 4, data.overloaded_float
+    end
+
+    def test_children_can_override_parents
+      data = GrandchildOfOverloadedType.new(overloaded_float: '4.4')
+
+      assert_equal 4.4, data.overloaded_float
+    end
+
+    def test_overloading_properties_does_not_change_column_order
+      column_names = OverloadedType.column_names
+      assert_equal %w(id overloaded_float unoverloaded_float overloaded_string_with_limit string_with_default non_existent_decimal), column_names
+    end
+
+    def test_caches_are_cleared
+      klass = Class.new(OverloadedType)
+
+      assert_equal 6, klass.columns.length
+      assert_not klass.columns_hash.key?('wibble')
+      assert_equal 6, klass.column_types.length
+      assert_equal 6, klass.column_defaults.length
+      assert_not klass.column_names.include?('wibble')
+      assert_equal 5, klass.content_columns.length
+
+      klass.attribute :wibble, Type::Value.new
+
+      assert_equal 7, klass.columns.length
+      assert klass.columns_hash.key?('wibble')
+      assert_equal 7, klass.column_types.length
+      assert_equal 7, klass.column_defaults.length
+      assert klass.column_names.include?('wibble')
+      assert_equal 6, klass.content_columns.length
+    end
+  end
+end
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
new file mode 100644
index 0000000000..09892d50ba
--- /dev/null
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -0,0 +1,1539 @@
+require 'cases/helper'
+require 'models/bird'
+require 'models/company'
+require 'models/customer'
+require 'models/developer'
+require 'models/invoice'
+require 'models/line_item'
+require 'models/order'
+require 'models/parrot'
+require 'models/person'
+require 'models/pirate'
+require 'models/post'
+require 'models/reader'
+require 'models/ship'
+require 'models/ship_part'
+require 'models/tag'
+require 'models/tagging'
+require 'models/treasure'
+require 'models/eye'
+require 'models/electron'
+require 'models/molecule'
+
+class TestAutosaveAssociationsInGeneral < ActiveRecord::TestCase
+  def test_autosave_validation
+    person = Class.new(ActiveRecord::Base) {
+      self.table_name = 'people'
+      validate :should_be_cool, :on => :create
+      def self.name; 'Person'; end
+
+      private
+
+      def should_be_cool
+        unless self.first_name == 'cool'
+          errors.add :first_name, "not cool"
+        end
+      end
+    }
+    reference = Class.new(ActiveRecord::Base) {
+      self.table_name = "references"
+      def self.name; 'Reference'; end
+      belongs_to :person, autosave: true, class: person
+    }
+
+    u = person.create!(first_name: 'cool')
+    u.update_attributes!(first_name: 'nah') # still valid because validation only applies on 'create'
+    assert reference.create!(person: u).persisted?
+  end
+
+  def test_should_not_add_the_same_callbacks_multiple_times_for_has_one
+    assert_no_difference_when_adding_callbacks_twice_for Pirate, :ship
+  end
+
+  def test_should_not_add_the_same_callbacks_multiple_times_for_belongs_to
+    assert_no_difference_when_adding_callbacks_twice_for Ship, :pirate
+  end
+
+  def test_should_not_add_the_same_callbacks_multiple_times_for_has_many
+    assert_no_difference_when_adding_callbacks_twice_for Pirate, :birds
+  end
+
+  def test_should_not_add_the_same_callbacks_multiple_times_for_has_and_belongs_to_many
+    assert_no_difference_when_adding_callbacks_twice_for Pirate, :parrots
+  end
+
+  private
+
+  def assert_no_difference_when_adding_callbacks_twice_for(model, association_name)
+    reflection = model.reflect_on_association(association_name)
+    assert_no_difference "callbacks_for_model(#{model.name}).length" do
+      model.send(:add_autosave_association_callbacks, reflection)
+    end
+  end
+
+  def callbacks_for_model(model)
+    model.instance_variables.grep(/_callbacks$/).flat_map do |ivar|
+      model.instance_variable_get(ivar)
+    end
+  end
+end
+
+class TestDefaultAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCase
+  fixtures :companies, :accounts
+
+  def test_should_save_parent_but_not_invalid_child
+    firm = Firm.new(:name => 'GlobalMegaCorp')
+    assert firm.valid?
+
+    firm.build_account_using_primary_key
+    assert !firm.build_account_using_primary_key.valid?
+
+    assert firm.save
+    assert !firm.account_using_primary_key.persisted?
+  end
+
+  def test_save_fails_for_invalid_has_one
+    firm = Firm.first
+    assert firm.valid?
+
+    firm.build_account
+
+    assert !firm.account.valid?
+    assert !firm.valid?
+    assert !firm.save
+    assert_equal ["is invalid"], firm.errors["account"]
+  end
+
+  def test_save_succeeds_for_invalid_has_one_with_validate_false
+    firm = Firm.first
+    assert firm.valid?
+
+    firm.build_unvalidated_account
+
+    assert !firm.unvalidated_account.valid?
+    assert firm.valid?
+    assert firm.save
+  end
+
+  def test_build_before_child_saved
+    firm = Firm.find(1)
+
+    account = firm.build_account("credit_limit" => 1000)
+    assert_equal account, firm.account
+    assert !account.persisted?
+    assert firm.save
+    assert_equal account, firm.account
+    assert account.persisted?
+  end
+
+  def test_build_before_either_saved
+    firm = Firm.new("name" => "GlobalMegaCorp")
+
+    firm.account = account = Account.new("credit_limit" => 1000)
+    assert_equal account, firm.account
+    assert !account.persisted?
+    assert firm.save
+    assert_equal account, firm.account
+    assert account.persisted?
+  end
+
+  def test_assignment_before_parent_saved
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.account = a = Account.find(1)
+    assert !firm.persisted?
+    assert_equal a, firm.account
+    assert firm.save
+    assert_equal a, firm.account
+    assert_equal a, firm.account(true)
+  end
+
+  def test_assignment_before_either_saved
+    firm = Firm.new("name" => "GlobalMegaCorp")
+    firm.account = a = Account.new("credit_limit" => 1000)
+    assert !firm.persisted?
+    assert !a.persisted?
+    assert_equal a, firm.account
+    assert firm.save
+    assert firm.persisted?
+    assert a.persisted?
+    assert_equal a, firm.account
+    assert_equal a, firm.account(true)
+  end
+
+  def test_not_resaved_when_unchanged
+    firm = Firm.all.merge!(:includes => :account).first
+    firm.name += '-changed'
+    assert_queries(1) { firm.save! }
+
+    firm = Firm.first
+    firm.account = Account.first
+    assert_queries(Firm.partial_writes? ? 0 : 1) { firm.save! }
+
+    firm = Firm.first.dup
+    firm.account = Account.first
+    assert_queries(2) { firm.save! }
+
+    firm = Firm.first.dup
+    firm.account = Account.first.dup
+    assert_queries(2) { firm.save! }
+  end
+
+  def test_callbacks_firing_order_on_create
+    eye = Eye.create(:iris_attributes => {:color => 'honey'})
+    assert_equal [true, false], eye.after_create_callbacks_stack
+  end
+
+  def test_callbacks_firing_order_on_update
+    eye = Eye.create(iris_attributes: {color: 'honey'})
+    eye.update(iris_attributes: {color: 'green'})
+    assert_equal [true, false], eye.after_update_callbacks_stack
+  end
+
+  def test_callbacks_firing_order_on_save
+    eye = Eye.create(iris_attributes: {color: 'honey'})
+    assert_equal [false, false], eye.after_save_callbacks_stack
+
+    eye.update(iris_attributes: {color: 'blue'})
+    assert_equal [false, false, false, false], eye.after_save_callbacks_stack
+  end
+end
+
+class TestDefaultAutosaveAssociationOnABelongsToAssociation < ActiveRecord::TestCase
+  fixtures :companies, :posts, :tags, :taggings
+
+  def test_should_save_parent_but_not_invalid_child
+    client = Client.new(:name => 'Joe (the Plumber)')
+    assert client.valid?
+
+    client.build_firm
+    assert !client.firm.valid?
+
+    assert client.save
+    assert !client.firm.persisted?
+  end
+
+  def test_save_fails_for_invalid_belongs_to
+    # Oracle saves empty string as NULL therefore :message changed to one space
+    assert log = AuditLog.create(:developer_id => 0, :message => " ")
+
+    log.developer = Developer.new
+    assert !log.developer.valid?
+    assert !log.valid?
+    assert !log.save
+    assert_equal ["is invalid"], log.errors["developer"]
+  end
+
+  def test_save_succeeds_for_invalid_belongs_to_with_validate_false
+    # Oracle saves empty string as NULL therefore :message changed to one space
+    assert log = AuditLog.create(:developer_id => 0, :message=> " ")
+
+    log.unvalidated_developer = Developer.new
+    assert !log.unvalidated_developer.valid?
+    assert log.valid?
+    assert log.save
+  end
+
+  def test_assignment_before_parent_saved
+    client = Client.first
+    apple = Firm.new("name" => "Apple")
+    client.firm = apple
+    assert_equal apple, client.firm
+    assert !apple.persisted?
+    assert client.save
+    assert apple.save
+    assert apple.persisted?
+    assert_equal apple, client.firm
+    assert_equal apple, client.firm(true)
+  end
+
+  def test_assignment_before_either_saved
+    final_cut = Client.new("name" => "Final Cut")
+    apple = Firm.new("name" => "Apple")
+    final_cut.firm = apple
+    assert !final_cut.persisted?
+    assert !apple.persisted?
+    assert final_cut.save
+    assert final_cut.persisted?
+    assert apple.persisted?
+    assert_equal apple, final_cut.firm
+    assert_equal apple, final_cut.firm(true)
+  end
+
+  def test_store_two_association_with_one_save
+    num_orders = Order.count
+    num_customers = Customer.count
+    order = Order.new
+
+    customer1 = order.billing = Customer.new
+    customer2 = order.shipping = Customer.new
+    assert order.save
+    assert_equal customer1, order.billing
+    assert_equal customer2, order.shipping
+
+    order.reload
+
+    assert_equal customer1, order.billing
+    assert_equal customer2, order.shipping
+
+    assert_equal num_orders + 1, Order.count
+    assert_equal num_customers + 2, Customer.count
+  end
+
+  def test_store_association_in_two_relations_with_one_save
+    num_orders = Order.count
+    num_customers = Customer.count
+    order = Order.new
+
+    customer = order.billing = order.shipping = Customer.new
+    assert order.save
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    order.reload
+
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    assert_equal num_orders + 1, Order.count
+    assert_equal num_customers + 1, Customer.count
+  end
+
+  def test_store_association_in_two_relations_with_one_save_in_existing_object
+    num_orders = Order.count
+    num_customers = Customer.count
+    order = Order.create
+
+    customer = order.billing = order.shipping = Customer.new
+    assert order.save
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    order.reload
+
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    assert_equal num_orders + 1, Order.count
+    assert_equal num_customers + 1, Customer.count
+  end
+
+  def test_store_association_in_two_relations_with_one_save_in_existing_object_with_values
+    num_orders = Order.count
+    num_customers = Customer.count
+    order = Order.create
+
+    customer = order.billing = order.shipping = Customer.new
+    assert order.save
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    order.reload
+
+    customer = order.billing = order.shipping = Customer.new
+
+    assert order.save
+    order.reload
+
+    assert_equal customer, order.billing
+    assert_equal customer, order.shipping
+
+    assert_equal num_orders + 1, Order.count
+    assert_equal num_customers + 2, Customer.count
+  end
+
+  def test_store_association_with_a_polymorphic_relationship
+    num_tagging = Tagging.count
+    tags(:misc).create_tagging(:taggable => posts(:thinking))
+    assert_equal num_tagging + 1, Tagging.count
+  end
+
+  def test_build_and_then_save_parent_should_not_reload_target
+    client = Client.first
+    apple = client.build_firm(:name => "Apple")
+    client.save!
+    assert_no_queries { assert_equal apple, client.firm }
+  end
+
+  def test_validation_does_not_validate_stale_association_target
+    valid_developer   = Developer.create!(:name => "Dude", :salary => 50_000)
+    invalid_developer = Developer.new()
+
+    auditlog = AuditLog.new(:message => "foo")
+    auditlog.developer    = invalid_developer
+    auditlog.developer_id = valid_developer.id
+
+    assert auditlog.valid?
+  end
+end
+
+class TestDefaultAutosaveAssociationOnAHasManyAssociationWithAcceptsNestedAttributes < ActiveRecord::TestCase
+  def test_invalid_adding_with_nested_attributes
+    molecule = Molecule.new
+    valid_electron = Electron.new(name: 'electron')
+    invalid_electron = Electron.new
+
+    molecule.electrons = [valid_electron, invalid_electron]
+    molecule.save
+
+    assert_not invalid_electron.valid?
+    assert valid_electron.valid?
+    assert_not molecule.persisted?, 'Molecule should not be persisted when its electrons are invalid'
+  end
+
+  def test_valid_adding_with_nested_attributes
+    molecule = Molecule.new
+    valid_electron = Electron.new(name: 'electron')
+
+    molecule.electrons = [valid_electron]
+    molecule.save
+
+    assert valid_electron.valid?
+    assert molecule.persisted?
+    assert_equal 1, molecule.electrons.count
+  end
+end
+
+class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCase
+  fixtures :companies, :people
+
+  def test_invalid_adding
+    firm = Firm.find(1)
+    assert !(firm.clients_of_firm << c = Client.new)
+    assert !c.persisted?
+    assert !firm.valid?
+    assert !firm.save
+    assert !c.persisted?
+  end
+
+  def test_invalid_adding_before_save
+    new_firm = Firm.new("name" => "A New Firm, Inc")
+    new_firm.clients_of_firm.concat([c = Client.new, Client.new("name" => "Apple")])
+    assert !c.persisted?
+    assert !c.valid?
+    assert !new_firm.valid?
+    assert !new_firm.save
+    assert !c.persisted?
+    assert !new_firm.persisted?
+  end
+
+  def test_invalid_adding_with_validate_false
+    firm = Firm.first
+    client = Client.new
+    firm.unvalidated_clients_of_firm << client
+
+    assert firm.valid?
+    assert !client.valid?
+    assert firm.save
+    assert !client.persisted?
+  end
+
+  def test_valid_adding_with_validate_false
+    no_of_clients = Client.count
+
+    firm = Firm.first
+    client = Client.new("name" => "Apple")
+
+    assert firm.valid?
+    assert client.valid?
+    assert !client.persisted?
+
+    firm.unvalidated_clients_of_firm << client
+
+    assert firm.save
+    assert client.persisted?
+    assert_equal no_of_clients + 1, Client.count
+  end
+
+  def test_invalid_build
+    new_client = companies(:first_firm).clients_of_firm.build
+    assert !new_client.persisted?
+    assert !new_client.valid?
+    assert_equal new_client, companies(:first_firm).clients_of_firm.last
+    assert !companies(:first_firm).save
+    assert !new_client.persisted?
+    assert_equal 2, companies(:first_firm).clients_of_firm(true).size
+  end
+
+  def test_adding_before_save
+    no_of_firms = Firm.count
+    no_of_clients = Client.count
+
+    new_firm = Firm.new("name" => "A New Firm, Inc")
+    c = Client.new("name" => "Apple")
+
+    new_firm.clients_of_firm.push Client.new("name" => "Natural Company")
+    assert_equal 1, new_firm.clients_of_firm.size
+    new_firm.clients_of_firm << c
+    assert_equal 2, new_firm.clients_of_firm.size
+
+    assert_equal no_of_firms, Firm.count      # Firm was not saved to database.
+    assert_equal no_of_clients, Client.count  # Clients were not saved to database.
+    assert new_firm.save
+    assert new_firm.persisted?
+    assert c.persisted?
+    assert_equal new_firm, c.firm
+    assert_equal no_of_firms + 1, Firm.count      # Firm was saved to database.
+    assert_equal no_of_clients + 2, Client.count  # Clients were saved to database.
+
+    assert_equal 2, new_firm.clients_of_firm.size
+    assert_equal 2, new_firm.clients_of_firm(true).size
+  end
+
+  def test_assign_ids
+    firm = Firm.new("name" => "Apple")
+    firm.client_ids = [companies(:first_client).id, companies(:second_client).id]
+    firm.save
+    firm.reload
+    assert_equal 2, firm.clients.length
+    assert firm.clients.include?(companies(:second_client))
+  end
+
+  def test_assign_ids_for_through_a_belongs_to
+    post = Post.new(:title => "Assigning IDs works!", :body => "You heard it here first, folks!")
+    post.person_ids = [people(:david).id, people(:michael).id]
+    post.save
+    post.reload
+    assert_equal 2, post.people.length
+    assert post.people.include?(people(:david))
+  end
+
+  def test_build_before_save
+    company = companies(:first_firm)
+    new_client = assert_no_queries { company.clients_of_firm.build("name" => "Another Client") }
+    assert !company.clients_of_firm.loaded?
+
+    company.name += '-changed'
+    assert_queries(2) { assert company.save }
+    assert new_client.persisted?
+    assert_equal 3, company.clients_of_firm(true).size
+  end
+
+  def test_build_many_before_save
+    company = companies(:first_firm)
+    assert_no_queries { company.clients_of_firm.build([{"name" => "Another Client"}, {"name" => "Another Client II"}]) }
+
+    company.name += '-changed'
+    assert_queries(3) { assert company.save }
+    assert_equal 4, company.clients_of_firm(true).size
+  end
+
+  def test_build_via_block_before_save
+    company = companies(:first_firm)
+    new_client = assert_no_queries { company.clients_of_firm.build {|client| client.name = "Another Client" } }
+    assert !company.clients_of_firm.loaded?
+
+    company.name += '-changed'
+    assert_queries(2) { assert company.save }
+    assert new_client.persisted?
+    assert_equal 3, company.clients_of_firm(true).size
+  end
+
+  def test_build_many_via_block_before_save
+    company = companies(:first_firm)
+    assert_no_queries do
+      company.clients_of_firm.build([{"name" => "Another Client"}, {"name" => "Another Client II"}]) do |client|
+        client.name = "changed"
+      end
+    end
+
+    company.name += '-changed'
+    assert_queries(3) { assert company.save }
+    assert_equal 4, company.clients_of_firm(true).size
+  end
+
+  def test_replace_on_new_object
+    firm = Firm.new("name" => "New Firm")
+    firm.clients = [companies(:second_client), Client.new("name" => "New Client")]
+    assert firm.save
+    firm.reload
+    assert_equal 2, firm.clients.length
+    assert firm.clients.include?(Client.find_by_name("New Client"))
+  end
+end
+
+class TestDefaultAutosaveAssociationOnNewRecord < ActiveRecord::TestCase
+  def test_autosave_new_record_on_belongs_to_can_be_disabled_per_relationship
+    new_account = Account.new("credit_limit" => 1000)
+    new_firm = Firm.new("name" => "some firm")
+
+    assert !new_firm.persisted?
+    new_account.firm = new_firm
+    new_account.save!
+
+    assert new_firm.persisted?
+
+    new_account = Account.new("credit_limit" => 1000)
+    new_autosaved_firm = Firm.new("name" => "some firm")
+
+    assert !new_autosaved_firm.persisted?
+    new_account.unautosaved_firm = new_autosaved_firm
+    new_account.save!
+
+    assert !new_autosaved_firm.persisted?
+  end
+
+  def test_autosave_new_record_on_has_one_can_be_disabled_per_relationship
+    firm = Firm.new("name" => "some firm")
+    account = Account.new("credit_limit" => 1000)
+
+    assert !account.persisted?
+    firm.account = account
+    firm.save!
+
+    assert account.persisted?
+
+    firm = Firm.new("name" => "some firm")
+    account = Account.new("credit_limit" => 1000)
+
+    firm.unautosaved_account = account
+
+    assert !account.persisted?
+    firm.unautosaved_account = account
+    firm.save!
+
+    assert !account.persisted?
+  end
+
+  def test_autosave_new_record_on_has_many_can_be_disabled_per_relationship
+    firm = Firm.new("name" => "some firm")
+    account = Account.new("credit_limit" => 1000)
+
+    assert !account.persisted?
+    firm.accounts << account
+
+    firm.save!
+    assert account.persisted?
+
+    firm = Firm.new("name" => "some firm")
+    account = Account.new("credit_limit" => 1000)
+
+    assert !account.persisted?
+    firm.unautosaved_accounts << account
+
+    firm.save!
+    assert !account.persisted?
+  end
+end
+
+class TestDestroyAsPartOfAutosaveAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  setup do
+    @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @ship = @pirate.create_ship(:name => 'Nights Dirty Lightning')
+  end
+
+  teardown do
+    # We are running without transactional fixtures and need to cleanup.
+    Bird.delete_all
+    Parrot.delete_all
+    @ship.delete
+    @pirate.delete
+  end
+
+  # reload
+  def test_a_marked_for_destruction_record_should_not_be_be_marked_after_reload
+    @pirate.mark_for_destruction
+    @pirate.ship.mark_for_destruction
+
+    assert !@pirate.reload.marked_for_destruction?
+    assert !@pirate.ship.reload.marked_for_destruction?
+  end
+
+  # has_one
+  def test_should_destroy_a_child_association_as_part_of_the_save_transaction_if_it_was_marked_for_destroyal
+    assert !@pirate.ship.marked_for_destruction?
+
+    @pirate.ship.mark_for_destruction
+    id = @pirate.ship.id
+
+    assert @pirate.ship.marked_for_destruction?
+    assert Ship.find_by_id(id)
+
+    @pirate.save
+    assert_nil @pirate.reload.ship
+    assert_nil Ship.find_by_id(id)
+  end
+
+  def test_should_skip_validation_on_a_child_association_if_marked_for_destruction
+    @pirate.ship.name = ''
+    assert !@pirate.valid?
+
+    @pirate.ship.mark_for_destruction
+    @pirate.ship.expects(:valid?).never
+    assert_difference('Ship.count', -1) { @pirate.save! }
+  end
+
+  def test_a_child_marked_for_destruction_should_not_be_destroyed_twice
+    @pirate.ship.mark_for_destruction
+    assert @pirate.save
+    class << @pirate.ship
+      def destroy; raise "Should not be called" end
+    end
+    assert @pirate.save
+  end
+
+  def test_should_rollback_destructions_if_an_exception_occurred_while_saving_a_child
+    # Stub the save method of the @pirate.ship instance to destroy and then raise an exception
+    class << @pirate.ship
+      def save(*args)
+        super
+        destroy
+        raise 'Oh noes!'
+      end
+    end
+
+    @ship.pirate.catchphrase = "Changed Catchphrase"
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_not_nil @pirate.reload.ship
+  end
+
+  def test_should_save_changed_has_one_changed_object_if_child_is_saved
+    @pirate.ship.name = "NewName"
+    assert @pirate.save
+    assert_equal "NewName", @pirate.ship.reload.name
+  end
+
+  def test_should_not_save_changed_has_one_unchanged_object_if_child_is_saved
+    @pirate.ship.expects(:save).never
+    assert @pirate.save
+  end
+
+  # belongs_to
+  def test_should_destroy_a_parent_association_as_part_of_the_save_transaction_if_it_was_marked_for_destroyal
+    assert !@ship.pirate.marked_for_destruction?
+
+    @ship.pirate.mark_for_destruction
+    id = @ship.pirate.id
+
+    assert @ship.pirate.marked_for_destruction?
+    assert Pirate.find_by_id(id)
+
+    @ship.save
+    assert_nil @ship.reload.pirate
+    assert_nil Pirate.find_by_id(id)
+  end
+
+  def test_should_skip_validation_on_a_parent_association_if_marked_for_destruction
+    @ship.pirate.catchphrase = ''
+    assert !@ship.valid?
+
+    @ship.pirate.mark_for_destruction
+    @ship.pirate.expects(:valid?).never
+    assert_difference('Pirate.count', -1) { @ship.save! }
+  end
+
+  def test_a_parent_marked_for_destruction_should_not_be_destroyed_twice
+    @ship.pirate.mark_for_destruction
+    assert @ship.save
+    class << @ship.pirate
+      def destroy; raise "Should not be called" end
+    end
+    assert @ship.save
+  end
+
+  def test_should_rollback_destructions_if_an_exception_occurred_while_saving_a_parent
+    # Stub the save method of the @ship.pirate instance to destroy and then raise an exception
+    class << @ship.pirate
+      def save(*args)
+        super
+        destroy
+        raise 'Oh noes!'
+      end
+    end
+
+    @ship.pirate.catchphrase = "Changed Catchphrase"
+
+    assert_raise(RuntimeError) { assert !@ship.save }
+    assert_not_nil @ship.reload.pirate
+  end
+
+  def test_should_save_changed_child_objects_if_parent_is_saved
+    @pirate = @ship.create_pirate(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @parrot = @pirate.parrots.create!(:name => 'Posideons Killer')
+    @parrot.name = "NewName"
+    @ship.save
+
+    assert_equal 'NewName', @parrot.reload.name
+  end
+
+  def test_should_destroy_has_many_as_part_of_the_save_transaction_if_they_were_marked_for_destruction
+    2.times { |i| @pirate.birds.create!(:name => "birds_#{i}") }
+
+    assert !@pirate.birds.any? { |child| child.marked_for_destruction? }
+
+    @pirate.birds.each { |child| child.mark_for_destruction }
+    klass = @pirate.birds.first.class
+    ids = @pirate.birds.map(&:id)
+
+    assert @pirate.birds.all? { |child| child.marked_for_destruction? }
+    ids.each { |id| assert klass.find_by_id(id) }
+
+    @pirate.save
+    assert @pirate.reload.birds.empty?
+    ids.each { |id| assert_nil klass.find_by_id(id) }
+  end
+
+  def test_should_not_resave_destroyed_association
+    @pirate.birds.create!(name: :parrot)
+    @pirate.birds.first.destroy
+    @pirate.save!
+    assert @pirate.reload.birds.empty?
+  end
+
+  def test_should_skip_validation_on_has_many_if_marked_for_destruction
+    2.times { |i| @pirate.birds.create!(:name => "birds_#{i}") }
+
+    @pirate.birds.each { |bird| bird.name = '' }
+    assert !@pirate.valid?
+
+    @pirate.birds.each do |bird|
+      bird.mark_for_destruction
+      bird.expects(:valid?).never
+    end
+    assert_difference("Bird.count", -2) { @pirate.save! }
+  end
+
+  def test_should_skip_validation_on_has_many_if_destroyed
+    @pirate.birds.create!(:name => "birds_1")
+
+    @pirate.birds.each { |bird| bird.name = '' }
+    assert !@pirate.valid?
+
+    @pirate.birds.each { |bird| bird.destroy }
+    assert @pirate.valid?
+  end
+
+  def test_a_child_marked_for_destruction_should_not_be_destroyed_twice_while_saving_has_many
+    @pirate.birds.create!(:name => "birds_1")
+
+    @pirate.birds.each { |bird| bird.mark_for_destruction }
+    assert @pirate.save
+
+    @pirate.birds.each { |bird| bird.expects(:destroy).never }
+    assert @pirate.save
+  end
+
+  def test_should_rollback_destructions_if_an_exception_occurred_while_saving_has_many
+    2.times { |i| @pirate.birds.create!(:name => "birds_#{i}") }
+    before = @pirate.birds.map { |c| c.mark_for_destruction ; c }
+
+    # Stub the destroy method of the second child to raise an exception
+    class << before.last
+      def destroy(*args)
+        super
+        raise 'Oh noes!'
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, @pirate.reload.birds
+  end
+
+  def test_when_new_record_a_child_marked_for_destruction_should_not_affect_other_records_from_saving
+    @pirate = @ship.build_pirate(:catchphrase => "Arr' now I shall keep me eye on you matey!") # new record
+
+    3.times { |i| @pirate.birds.build(:name => "birds_#{i}") }
+    @pirate.birds[1].mark_for_destruction
+    @pirate.save!
+
+    assert_equal 2, @pirate.birds.reload.length
+  end
+
+  def test_should_save_new_record_that_has_same_value_as_existing_record_marked_for_destruction_on_field_that_has_unique_index
+    Bird.connection.add_index :birds, :name, unique: true
+
+    3.times { |i| @pirate.birds.create(name: "unique_birds_#{i}") }
+
+    @pirate.birds[0].mark_for_destruction
+    @pirate.birds.build(name: @pirate.birds[0].name)
+    @pirate.save!
+
+    assert_equal 3, @pirate.birds.reload.length
+  ensure
+    Bird.connection.remove_index :birds, column: :name
+  end
+
+  # Add and remove callbacks tests for association collections.
+  %w{ method proc }.each do |callback_type|
+    define_method("test_should_run_add_callback_#{callback_type}s_for_has_many") do
+      association_name_with_callbacks = "birds_with_#{callback_type}_callbacks"
+
+      pirate = Pirate.new(:catchphrase => "Arr")
+      pirate.send(association_name_with_callbacks).build(:name => "Crowe the One-Eyed")
+
+      expected = [
+        "before_adding_#{callback_type}_bird_<new>",
+        "after_adding_#{callback_type}_bird_<new>"
+      ]
+
+      assert_equal expected, pirate.ship_log
+    end
+
+    define_method("test_should_run_remove_callback_#{callback_type}s_for_has_many") do
+      association_name_with_callbacks = "birds_with_#{callback_type}_callbacks"
+
+      @pirate.send(association_name_with_callbacks).create!(:name => "Crowe the One-Eyed")
+      @pirate.send(association_name_with_callbacks).each { |c| c.mark_for_destruction }
+      child_id = @pirate.send(association_name_with_callbacks).first.id
+
+      @pirate.ship_log.clear
+      @pirate.save
+
+      expected = [
+        "before_removing_#{callback_type}_bird_#{child_id}",
+        "after_removing_#{callback_type}_bird_#{child_id}"
+      ]
+
+      assert_equal expected, @pirate.ship_log
+    end
+  end
+
+  def test_should_destroy_habtm_as_part_of_the_save_transaction_if_they_were_marked_for_destruction
+    2.times { |i| @pirate.parrots.create!(:name => "parrots_#{i}") }
+
+    assert !@pirate.parrots.any? { |parrot| parrot.marked_for_destruction? }
+    @pirate.parrots.each { |parrot| parrot.mark_for_destruction }
+
+    assert_no_difference "Parrot.count" do
+      @pirate.save
+    end
+
+    assert @pirate.reload.parrots.empty?
+
+    join_records = Pirate.connection.select_all("SELECT * FROM parrots_pirates WHERE pirate_id = #{@pirate.id}")
+    assert join_records.empty?
+  end
+
+  def test_should_skip_validation_on_habtm_if_marked_for_destruction
+    2.times { |i| @pirate.parrots.create!(:name => "parrots_#{i}") }
+
+    @pirate.parrots.each { |parrot| parrot.name = '' }
+    assert !@pirate.valid?
+
+    @pirate.parrots.each do |parrot|
+      parrot.mark_for_destruction
+      parrot.expects(:valid?).never
+    end
+
+    @pirate.save!
+    assert @pirate.reload.parrots.empty?
+  end
+
+  def test_should_skip_validation_on_habtm_if_destroyed
+    @pirate.parrots.create!(:name => "parrots_1")
+
+    @pirate.parrots.each { |parrot| parrot.name = '' }
+    assert !@pirate.valid?
+
+    @pirate.parrots.each { |parrot| parrot.destroy }
+    assert @pirate.valid?
+  end
+
+  def test_a_child_marked_for_destruction_should_not_be_destroyed_twice_while_saving_habtm
+    @pirate.parrots.create!(:name => "parrots_1")
+
+    @pirate.parrots.each { |parrot| parrot.mark_for_destruction }
+    assert @pirate.save
+
+    Pirate.transaction do
+      assert_queries(0) do
+        assert @pirate.save
+      end
+    end
+  end
+
+  def test_should_rollback_destructions_if_an_exception_occurred_while_saving_habtm
+    2.times { |i| @pirate.parrots.create!(:name => "parrots_#{i}") }
+    before = @pirate.parrots.map { |c| c.mark_for_destruction ; c }
+
+    class << @pirate.association(:parrots)
+      def destroy(*args)
+        super
+        raise 'Oh noes!'
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, @pirate.reload.parrots
+  end
+
+  # Add and remove callbacks tests for association collections.
+  %w{ method proc }.each do |callback_type|
+    define_method("test_should_run_add_callback_#{callback_type}s_for_habtm") do
+      association_name_with_callbacks = "parrots_with_#{callback_type}_callbacks"
+
+      pirate = Pirate.new(:catchphrase => "Arr")
+      pirate.send(association_name_with_callbacks).build(:name => "Crowe the One-Eyed")
+
+      expected = [
+        "before_adding_#{callback_type}_parrot_<new>",
+        "after_adding_#{callback_type}_parrot_<new>"
+      ]
+
+      assert_equal expected, pirate.ship_log
+    end
+
+    define_method("test_should_run_remove_callback_#{callback_type}s_for_habtm") do
+      association_name_with_callbacks = "parrots_with_#{callback_type}_callbacks"
+
+      @pirate.send(association_name_with_callbacks).create!(:name => "Crowe the One-Eyed")
+      @pirate.send(association_name_with_callbacks).each { |c| c.mark_for_destruction }
+      child_id = @pirate.send(association_name_with_callbacks).first.id
+
+      @pirate.ship_log.clear
+      @pirate.save
+
+      expected = [
+        "before_removing_#{callback_type}_parrot_#{child_id}",
+        "after_removing_#{callback_type}_parrot_#{child_id}"
+      ]
+
+      assert_equal expected, @pirate.ship_log
+    end
+  end
+end
+
+class TestAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @ship = @pirate.create_ship(:name => 'Nights Dirty Lightning')
+  end
+
+  def test_should_still_work_without_an_associated_model
+    @ship.destroy
+    @pirate.reload.catchphrase = "Arr"
+    @pirate.save
+    assert_equal 'Arr', @pirate.reload.catchphrase
+  end
+
+  def test_should_automatically_save_the_associated_model
+    @pirate.ship.name = 'The Vile Insanity'
+    @pirate.save
+    assert_equal 'The Vile Insanity', @pirate.reload.ship.name
+  end
+
+  def test_should_automatically_save_bang_the_associated_model
+    @pirate.ship.name = 'The Vile Insanity'
+    @pirate.save!
+    assert_equal 'The Vile Insanity', @pirate.reload.ship.name
+  end
+
+  def test_should_automatically_validate_the_associated_model
+    @pirate.ship.name = ''
+    assert @pirate.invalid?
+    assert @pirate.errors[:"ship.name"].any?
+  end
+
+  def test_should_merge_errors_on_the_associated_models_onto_the_parent_even_if_it_is_not_valid
+    @pirate.ship.name   = nil
+    @pirate.catchphrase = nil
+    assert @pirate.invalid?
+    assert @pirate.errors[:"ship.name"].any?
+    assert @pirate.errors[:catchphrase].any?
+  end
+
+  def test_should_not_ignore_different_error_messages_on_the_same_attribute
+    Ship.validates_format_of :name, :with => /\w/
+    @pirate.ship.name   = ""
+    @pirate.catchphrase = nil
+    assert @pirate.invalid?
+    assert_equal ["can't be blank", "is invalid"], @pirate.errors[:"ship.name"]
+  end
+
+  def test_should_still_allow_to_bypass_validations_on_the_associated_model
+    @pirate.catchphrase = ''
+    @pirate.ship.name = ''
+    @pirate.save(:validate => false)
+    # Oracle saves empty string as NULL
+    if current_adapter?(:OracleAdapter)
+      assert_equal [nil, nil], [@pirate.reload.catchphrase, @pirate.ship.name]
+    else
+      assert_equal ['', ''], [@pirate.reload.catchphrase, @pirate.ship.name]
+    end
+  end
+
+  def test_should_allow_to_bypass_validations_on_associated_models_at_any_depth
+    2.times { |i| @pirate.ship.parts.create!(:name => "part #{i}") }
+
+    @pirate.catchphrase = ''
+    @pirate.ship.name = ''
+    @pirate.ship.parts.each { |part| part.name = '' }
+    @pirate.save(:validate => false)
+
+    values = [@pirate.reload.catchphrase, @pirate.ship.name, *@pirate.ship.parts.map(&:name)]
+    # Oracle saves empty string as NULL
+    if current_adapter?(:OracleAdapter)
+      assert_equal [nil, nil, nil, nil], values
+    else
+      assert_equal ['', '', '', ''], values
+    end
+  end
+
+  def test_should_still_raise_an_ActiveRecordRecord_Invalid_exception_if_we_want_that
+    @pirate.ship.name = ''
+    assert_raise(ActiveRecord::RecordInvalid) do
+      @pirate.save!
+    end
+  end
+
+  def test_should_not_save_and_return_false_if_a_callback_cancelled_saving
+    pirate = Pirate.new(:catchphrase => 'Arr')
+    ship = pirate.build_ship(:name => 'The Vile Insanity')
+    ship.cancel_save_from_callback = true
+
+    assert_no_difference 'Pirate.count' do
+      assert_no_difference 'Ship.count' do
+        assert !pirate.save
+      end
+    end
+  end
+
+  def test_should_rollback_any_changes_if_an_exception_occurred_while_saving
+    before = [@pirate.catchphrase, @pirate.ship.name]
+
+    @pirate.catchphrase = 'Arr'
+    @pirate.ship.name = 'The Vile Insanity'
+
+    # Stub the save method of the @pirate.ship instance to raise an exception
+    class << @pirate.ship
+      def save(*args)
+        super
+        raise 'Oh noes!'
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, [@pirate.reload.catchphrase, @pirate.ship.name]
+  end
+
+  def test_should_not_load_the_associated_model
+    assert_queries(1) { @pirate.catchphrase = 'Arr'; @pirate.save! }
+  end
+end
+
+class TestAutosaveAssociationOnABelongsToAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @ship = Ship.create(:name => 'Nights Dirty Lightning')
+    @pirate = @ship.create_pirate(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+  end
+
+  def test_should_still_work_without_an_associated_model
+    @pirate.destroy
+    @ship.reload.name = "The Vile Insanity"
+    @ship.save
+    assert_equal 'The Vile Insanity', @ship.reload.name
+  end
+
+  def test_should_automatically_save_the_associated_model
+    @ship.pirate.catchphrase = 'Arr'
+    @ship.save
+    assert_equal 'Arr', @ship.reload.pirate.catchphrase
+  end
+
+  def test_should_automatically_save_bang_the_associated_model
+    @ship.pirate.catchphrase = 'Arr'
+    @ship.save!
+    assert_equal 'Arr', @ship.reload.pirate.catchphrase
+  end
+
+  def test_should_automatically_validate_the_associated_model
+    @ship.pirate.catchphrase = ''
+    assert @ship.invalid?
+    assert @ship.errors[:"pirate.catchphrase"].any?
+  end
+
+  def test_should_merge_errors_on_the_associated_model_onto_the_parent_even_if_it_is_not_valid
+    @ship.name = nil
+    @ship.pirate.catchphrase = nil
+    assert @ship.invalid?
+    assert @ship.errors[:name].any?
+    assert @ship.errors[:"pirate.catchphrase"].any?
+  end
+
+  def test_should_still_allow_to_bypass_validations_on_the_associated_model
+    @ship.pirate.catchphrase = ''
+    @ship.name = ''
+    @ship.save(:validate => false)
+    # Oracle saves empty string as NULL
+    if current_adapter?(:OracleAdapter)
+      assert_equal [nil, nil], [@ship.reload.name, @ship.pirate.catchphrase]
+    else
+      assert_equal ['', ''], [@ship.reload.name, @ship.pirate.catchphrase]
+    end
+  end
+
+  def test_should_still_raise_an_ActiveRecordRecord_Invalid_exception_if_we_want_that
+    @ship.pirate.catchphrase = ''
+    assert_raise(ActiveRecord::RecordInvalid) do
+      @ship.save!
+    end
+  end
+
+  def test_should_not_save_and_return_false_if_a_callback_cancelled_saving
+    ship = Ship.new(:name => 'The Vile Insanity')
+    pirate = ship.build_pirate(:catchphrase => 'Arr')
+    pirate.cancel_save_from_callback = true
+
+    assert_no_difference 'Ship.count' do
+      assert_no_difference 'Pirate.count' do
+        assert !ship.save
+      end
+    end
+  end
+
+  def test_should_rollback_any_changes_if_an_exception_occurred_while_saving
+    before = [@ship.pirate.catchphrase, @ship.name]
+
+    @ship.pirate.catchphrase = 'Arr'
+    @ship.name = 'The Vile Insanity'
+
+    # Stub the save method of the @ship.pirate instance to raise an exception
+    class << @ship.pirate
+      def save(*args)
+        super
+        raise 'Oh noes!'
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@ship.save }
+    assert_equal before, [@ship.pirate.reload.catchphrase, @ship.reload.name]
+  end
+
+  def test_should_not_load_the_associated_model
+    assert_queries(1) { @ship.name = 'The Vile Insanity'; @ship.save! }
+  end
+end
+
+module AutosaveAssociationOnACollectionAssociationTests
+  def test_should_automatically_save_the_associated_models
+    new_names = ['Grace OMalley', 'Privateers Greed']
+    @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
+
+    @pirate.save
+    assert_equal new_names, @pirate.reload.send(@association_name).map(&:name)
+  end
+
+  def test_should_automatically_save_bang_the_associated_models
+    new_names = ['Grace OMalley', 'Privateers Greed']
+    @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
+
+    @pirate.save!
+    assert_equal new_names, @pirate.reload.send(@association_name).map(&:name)
+  end
+
+  def test_should_automatically_validate_the_associated_models
+    @pirate.send(@association_name).each { |child| child.name = '' }
+
+    assert !@pirate.valid?
+    assert_equal ["can't be blank"], @pirate.errors["#{@association_name}.name"]
+    assert @pirate.errors[@association_name].empty?
+  end
+
+  def test_should_not_use_default_invalid_error_on_associated_models
+    @pirate.send(@association_name).build(:name => '')
+
+    assert !@pirate.valid?
+    assert_equal ["can't be blank"], @pirate.errors["#{@association_name}.name"]
+    assert @pirate.errors[@association_name].empty?
+  end
+
+  def test_should_default_invalid_error_from_i18n
+    I18n.backend.store_translations(:en, activerecord: {errors: { models:
+      { @associated_model_name.to_s.to_sym => { blank: "cannot be blank" } }
+    }})
+
+    @pirate.send(@association_name).build(name: '')
+
+    assert !@pirate.valid?
+    assert_equal ["cannot be blank"], @pirate.errors["#{@association_name}.name"]
+    assert_equal ["#{@association_name.to_s.humanize} name cannot be blank"], @pirate.errors.full_messages
+    assert @pirate.errors[@association_name].empty?
+  ensure
+    I18n.backend = I18n::Backend::Simple.new
+  end
+
+  def test_should_merge_errors_on_the_associated_models_onto_the_parent_even_if_it_is_not_valid
+    @pirate.send(@association_name).each { |child| child.name = '' }
+    @pirate.catchphrase = nil
+
+    assert !@pirate.valid?
+    assert_equal ["can't be blank"], @pirate.errors["#{@association_name}.name"]
+    assert @pirate.errors[:catchphrase].any?
+  end
+
+  def test_should_allow_to_bypass_validations_on_the_associated_models_on_update
+    @pirate.catchphrase = ''
+    @pirate.send(@association_name).each { |child| child.name = '' }
+
+    assert @pirate.save(:validate => false)
+    # Oracle saves empty string as NULL
+    if current_adapter?(:OracleAdapter)
+      assert_equal [nil, nil, nil], [
+        @pirate.reload.catchphrase,
+        @pirate.send(@association_name).first.name,
+        @pirate.send(@association_name).last.name
+      ]
+    else
+      assert_equal ['', '', ''], [
+        @pirate.reload.catchphrase,
+        @pirate.send(@association_name).first.name,
+        @pirate.send(@association_name).last.name
+      ]
+    end
+  end
+
+  def test_should_validation_the_associated_models_on_create
+    assert_no_difference("#{ @association_name == :birds ? 'Bird' : 'Parrot' }.count") do
+      2.times { @pirate.send(@association_name).build }
+      @pirate.save
+    end
+  end
+
+  def test_should_allow_to_bypass_validations_on_the_associated_models_on_create
+    assert_difference("#{ @association_name == :birds ? 'Bird' : 'Parrot' }.count", 2) do
+      2.times { @pirate.send(@association_name).build }
+      @pirate.save(:validate => false)
+    end
+  end
+
+  def test_should_not_save_and_return_false_if_a_callback_cancelled_saving_in_either_create_or_update
+    @pirate.catchphrase = 'Changed'
+    @child_1.name = 'Changed'
+    @child_1.cancel_save_from_callback = true
+
+    assert !@pirate.save
+    assert_equal "Don' botharrr talkin' like one, savvy?", @pirate.reload.catchphrase
+    assert_equal "Posideons Killer", @child_1.reload.name
+
+    new_pirate = Pirate.new(:catchphrase => 'Arr')
+    new_child = new_pirate.send(@association_name).build(:name => 'Grace OMalley')
+    new_child.cancel_save_from_callback = true
+
+    assert_no_difference 'Pirate.count' do
+      assert_no_difference "#{new_child.class.name}.count" do
+        assert !new_pirate.save
+      end
+    end
+  end
+
+  def test_should_rollback_any_changes_if_an_exception_occurred_while_saving
+    before = [@pirate.catchphrase, *@pirate.send(@association_name).map(&:name)]
+    new_names = ['Grace OMalley', 'Privateers Greed']
+
+    @pirate.catchphrase = 'Arr'
+    @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
+
+    # Stub the save method of the first child instance to raise an exception
+    class << @pirate.send(@association_name).first
+      def save(*args)
+        super
+        raise 'Oh noes!'
+      end
+    end
+
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, [@pirate.reload.catchphrase, *@pirate.send(@association_name).map(&:name)]
+  end
+
+  def test_should_still_raise_an_ActiveRecordRecord_Invalid_exception_if_we_want_that
+    @pirate.send(@association_name).each { |child| child.name = '' }
+    assert_raise(ActiveRecord::RecordInvalid) do
+      @pirate.save!
+    end
+  end
+
+  def test_should_not_load_the_associated_models_if_they_were_not_loaded_yet
+    assert_queries(1) { @pirate.catchphrase = 'Arr'; @pirate.save! }
+
+    @pirate.send(@association_name).load_target
+
+    assert_queries(3) do
+      @pirate.catchphrase = 'Yarr'
+      new_names = ['Grace OMalley', 'Privateers Greed']
+      @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
+      @pirate.save!
+    end
+  end
+end
+
+class TestAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @association_name = :birds
+    @associated_model_name = :bird
+
+    @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @child_1 = @pirate.birds.create(:name => 'Posideons Killer')
+    @child_2 = @pirate.birds.create(:name => 'Killer bandita Dionne')
+  end
+
+  include AutosaveAssociationOnACollectionAssociationTests
+end
+
+class TestAutosaveAssociationOnAHasAndBelongsToManyAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @association_name = :autosaved_parrots
+    @associated_model_name = :parrot
+    @habtm = true
+
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @child_1 = @pirate.parrots.create(name: 'Posideons Killer')
+    @child_2 = @pirate.parrots.create(name: 'Killer bandita Dionne')
+  end
+
+  include AutosaveAssociationOnACollectionAssociationTests
+end
+
+class TestAutosaveAssociationOnAHasAndBelongsToManyAssociationWithAcceptsNestedAttributes < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @association_name = :parrots
+    @associated_model_name = :parrot
+    @habtm = true
+
+    @pirate = Pirate.create(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    @child_1 = @pirate.parrots.create(name: 'Posideons Killer')
+    @child_2 = @pirate.parrots.create(name: 'Killer bandita Dionne')
+  end
+
+  include AutosaveAssociationOnACollectionAssociationTests
+end
+
+class TestAutosaveAssociationValidationsOnAHasManyAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @pirate.birds.create(:name => 'cookoo')
+  end
+
+  test "should automatically validate associations" do
+    assert @pirate.valid?
+    @pirate.birds.each { |bird| bird.name = '' }
+
+    assert !@pirate.valid?
+  end
+end
+
+class TestAutosaveAssociationValidationsOnAHasOneAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @pirate.create_ship(:name => 'titanic')
+    super
+  end
+
+  test "should automatically validate associations with :validate => true" do
+    assert @pirate.valid?
+    @pirate.ship.name = ''
+    assert !@pirate.valid?
+  end
+
+  test "should not automatically add validate associations without :validate => true" do
+    assert @pirate.valid?
+    @pirate.non_validated_ship.name = ''
+    assert @pirate.valid?
+  end
+end
+
+class TestAutosaveAssociationValidationsOnABelongsToAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+  end
+
+  test "should automatically validate associations with :validate => true" do
+    assert @pirate.valid?
+    @pirate.parrot = Parrot.new(:name => '')
+    assert !@pirate.valid?
+  end
+
+  test "should not automatically validate associations without :validate => true" do
+    assert @pirate.valid?
+    @pirate.non_validated_parrot = Parrot.new(:name => '')
+    assert @pirate.valid?
+  end
+end
+
+class TestAutosaveAssociationValidationsOnAHABTMAssociation < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+  end
+
+  test "should automatically validate associations with :validate => true" do
+    assert @pirate.valid?
+    @pirate.parrots = [ Parrot.new(:name => 'popuga') ]
+    @pirate.parrots.each { |parrot| parrot.name = '' }
+    assert !@pirate.valid?
+  end
+
+  test "should not automatically validate associations without :validate => true" do
+    assert @pirate.valid?
+    @pirate.non_validated_parrots = [ Parrot.new(:name => 'popuga') ]
+    @pirate.non_validated_parrots.each { |parrot| parrot.name = '' }
+    assert @pirate.valid?
+  end
+end
+
+class TestAutosaveAssociationValidationMethodsGeneration < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    super
+    @pirate = Pirate.new
+  end
+
+  test "should generate validation methods for has_many associations" do
+    assert_respond_to @pirate, :validate_associated_records_for_birds
+  end
+
+  test "should generate validation methods for has_one associations with :validate => true" do
+    assert_respond_to @pirate, :validate_associated_records_for_ship
+  end
+
+  test "should not generate validation methods for has_one associations without :validate => true" do
+    assert !@pirate.respond_to?(:validate_associated_records_for_non_validated_ship)
+  end
+
+  test "should generate validation methods for belongs_to associations with :validate => true" do
+    assert_respond_to @pirate, :validate_associated_records_for_parrot
+  end
+
+  test "should not generate validation methods for belongs_to associations without :validate => true" do
+    assert !@pirate.respond_to?(:validate_associated_records_for_non_validated_parrot)
+  end
+
+  test "should generate validation methods for HABTM associations with :validate => true" do
+    assert_respond_to @pirate, :validate_associated_records_for_parrots
+  end
+end
+
+class TestAutosaveAssociationWithTouch < ActiveRecord::TestCase
+  def test_autosave_with_touch_should_not_raise_system_stack_error
+    invoice = Invoice.create
+    assert_nothing_raised { invoice.line_items.create(:amount => 10) }
+  end
+end
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
new file mode 100644
index 0000000000..4c0b0c868a
--- /dev/null
+++ b/activerecord/test/cases/base_test.rb
@@ -0,0 +1,1624 @@
+# encoding: utf-8
+
+require "cases/helper"
+require 'active_support/concurrency/latch'
+require 'models/post'
+require 'models/author'
+require 'models/topic'
+require 'models/reply'
+require 'models/category'
+require 'models/company'
+require 'models/customer'
+require 'models/developer'
+require 'models/project'
+require 'models/default'
+require 'models/auto_id'
+require 'models/boolean'
+require 'models/column_name'
+require 'models/subscriber'
+require 'models/keyboard'
+require 'models/comment'
+require 'models/minimalistic'
+require 'models/warehouse_thing'
+require 'models/parrot'
+require 'models/person'
+require 'models/edge'
+require 'models/joke'
+require 'models/bird'
+require 'models/car'
+require 'models/bulb'
+require 'rexml/document'
+
+class FirstAbstractClass < ActiveRecord::Base
+  self.abstract_class = true
+end
+class SecondAbstractClass < FirstAbstractClass
+  self.abstract_class = true
+end
+class Photo < SecondAbstractClass; end
+class Category < ActiveRecord::Base; end
+class Categorization < ActiveRecord::Base; end
+class Smarts < ActiveRecord::Base; end
+class CreditCard < ActiveRecord::Base
+  class PinNumber < ActiveRecord::Base
+    class CvvCode < ActiveRecord::Base; end
+    class SubCvvCode < CvvCode; end
+  end
+  class SubPinNumber < PinNumber; end
+  class Brand < Category; end
+end
+class MasterCreditCard < ActiveRecord::Base; end
+class Post < ActiveRecord::Base; end
+class Computer < ActiveRecord::Base; end
+class NonExistentTable < ActiveRecord::Base; end
+class TestOracleDefault < ActiveRecord::Base; end
+
+class ReadonlyTitlePost < Post
+  attr_readonly :title
+end
+
+class Weird < ActiveRecord::Base; end
+
+class Boolean < ActiveRecord::Base
+  def has_fun
+    super
+  end
+end
+
+class LintTest < ActiveRecord::TestCase
+  include ActiveModel::Lint::Tests
+
+  class LintModel < ActiveRecord::Base; end
+
+  def setup
+    @model = LintModel.new
+  end
+end
+
+class BasicsTest < ActiveRecord::TestCase
+  fixtures :topics, :companies, :developers, :projects, :computers, :accounts, :minimalistics, 'warehouse-things', :authors, :categorizations, :categories, :posts
+
+  def test_column_names_are_escaped
+    conn      = ActiveRecord::Base.connection
+    classname = conn.class.name[/[^:]*$/]
+    badchar   = {
+      'SQLite3Adapter'    => '"',
+      'MysqlAdapter'      => '`',
+      'Mysql2Adapter'     => '`',
+      'PostgreSQLAdapter' => '"',
+      'OracleAdapter'     => '"',
+    }.fetch(classname) {
+      raise "need a bad char for #{classname}"
+    }
+
+    quoted = conn.quote_column_name "foo#{badchar}bar"
+    if current_adapter?(:OracleAdapter)
+      # Oracle does not allow double quotes in table and column names at all
+      # therefore quoting removes them
+      assert_equal("#{badchar}foobar#{badchar}", quoted)
+    else
+      assert_equal("#{badchar}foo#{badchar * 2}bar#{badchar}", quoted)
+    end
+  end
+
+  def test_columns_should_obey_set_primary_key
+    pk = Subscriber.columns_hash[Subscriber.primary_key]
+    assert_equal 'nick', pk.name, 'nick should be primary key'
+  end
+
+  def test_primary_key_with_no_id
+    assert_nil Edge.primary_key
+  end
+
+  unless current_adapter?(:PostgreSQLAdapter, :OracleAdapter, :SQLServerAdapter)
+    def test_limit_with_comma
+      assert Topic.limit("1,2").to_a
+    end
+  end
+
+  def test_limit_without_comma
+    assert_equal 1, Topic.limit("1").to_a.length
+    assert_equal 1, Topic.limit(1).to_a.length
+  end
+
+  def test_limit_should_take_value_from_latest_limit
+    assert_equal 1, Topic.limit(2).limit(1).to_a.length
+  end
+
+  def test_invalid_limit
+    assert_raises(ArgumentError) do
+      Topic.limit("asdfadf").to_a
+    end
+  end
+
+  def test_limit_should_sanitize_sql_injection_for_limit_without_commas
+    assert_raises(ArgumentError) do
+      Topic.limit("1 select * from schema").to_a
+    end
+  end
+
+  def test_limit_should_sanitize_sql_injection_for_limit_with_commas
+    assert_raises(ArgumentError) do
+      Topic.limit("1, 7 procedure help()").to_a
+    end
+  end
+
+  unless current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+    def test_limit_should_allow_sql_literal
+      assert_equal 1, Topic.limit(Arel.sql('2-1')).to_a.length
+    end
+  end
+
+  def test_select_symbol
+    topic_ids = Topic.select(:id).map(&:id).sort
+    assert_equal Topic.pluck(:id).sort, topic_ids
+  end
+
+  def test_table_exists
+    assert !NonExistentTable.table_exists?
+    assert Topic.table_exists?
+  end
+
+  def test_preserving_date_objects
+    # Oracle enhanced adapter allows to define Date attributes in model class (see topic.rb)
+    assert_kind_of(
+      Date, Topic.find(1).last_read,
+      "The last_read attribute should be of the Date class"
+    )
+  end
+
+  def test_previously_changed
+    topic = Topic.first
+    topic.title = '<3<3<3'
+    assert_equal({}, topic.previous_changes)
+
+    topic.save!
+    expected = ["The First Topic", "<3<3<3"]
+    assert_equal(expected, topic.previous_changes['title'])
+  end
+
+  def test_previously_changed_dup
+    topic = Topic.first
+    topic.title = '<3<3<3'
+    topic.save!
+
+    t2 = topic.dup
+
+    assert_equal(topic.previous_changes, t2.previous_changes)
+
+    topic.title = "lolwut"
+    topic.save!
+
+    assert_not_equal(topic.previous_changes, t2.previous_changes)
+  end
+
+  def test_preserving_time_objects
+    assert_kind_of(
+      Time, Topic.find(1).bonus_time,
+      "The bonus_time attribute should be of the Time class"
+    )
+
+    assert_kind_of(
+      Time, Topic.find(1).written_on,
+      "The written_on attribute should be of the Time class"
+    )
+
+    # For adapters which support microsecond resolution.
+    if current_adapter?(:PostgreSQLAdapter, :SQLite3Adapter) || mysql_56?
+      assert_equal 11, Topic.find(1).written_on.sec
+      assert_equal 223300, Topic.find(1).written_on.usec
+      assert_equal 9900, Topic.find(2).written_on.usec
+      assert_equal 129346, Topic.find(3).written_on.usec
+    end
+  end
+
+  def test_preserving_time_objects_with_local_time_conversion_to_default_timezone_utc
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :utc do
+        time = Time.local(2000)
+        topic = Topic.create('written_on' => time)
+        saved_time = Topic.find(topic.id).reload.written_on
+        assert_equal time, saved_time
+        assert_equal [0, 0, 0, 1, 1, 2000, 6, 1, false, "EST"], time.to_a
+        assert_equal [0, 0, 5, 1, 1, 2000, 6, 1, false, "UTC"], saved_time.to_a
+      end
+    end
+  end
+
+  def test_preserving_time_objects_with_time_with_zone_conversion_to_default_timezone_utc
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :utc do
+        Time.use_zone 'Central Time (US & Canada)' do
+          time = Time.zone.local(2000)
+          topic = Topic.create('written_on' => time)
+          saved_time = Topic.find(topic.id).reload.written_on
+          assert_equal time, saved_time
+          assert_equal [0, 0, 0, 1, 1, 2000, 6, 1, false, "CST"], time.to_a
+          assert_equal [0, 0, 6, 1, 1, 2000, 6, 1, false, "UTC"], saved_time.to_a
+        end
+      end
+    end
+  end
+
+  def test_preserving_time_objects_with_utc_time_conversion_to_default_timezone_local
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :local do
+        time = Time.utc(2000)
+        topic = Topic.create('written_on' => time)
+        saved_time = Topic.find(topic.id).reload.written_on
+        assert_equal time, saved_time
+        assert_equal [0, 0, 0, 1, 1, 2000, 6, 1, false, "UTC"], time.to_a
+        assert_equal [0, 0, 19, 31, 12, 1999, 5, 365, false, "EST"], saved_time.to_a
+      end
+    end
+  end
+
+  def test_preserving_time_objects_with_time_with_zone_conversion_to_default_timezone_local
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :local do
+        Time.use_zone 'Central Time (US & Canada)' do
+          time = Time.zone.local(2000)
+          topic = Topic.create('written_on' => time)
+          saved_time = Topic.find(topic.id).reload.written_on
+          assert_equal time, saved_time
+          assert_equal [0, 0, 0, 1, 1, 2000, 6, 1, false, "CST"], time.to_a
+          assert_equal [0, 0, 1, 1, 1, 2000, 6, 1, false, "EST"], saved_time.to_a
+        end
+      end
+    end
+  end
+
+  def test_custom_mutator
+    topic = Topic.find(1)
+    # This mutator is protected in the class definition
+    topic.send(:approved=, true)
+    assert topic.instance_variable_get("@custom_approved")
+  end
+
+  def test_initialize_with_attributes
+    topic = Topic.new({
+      "title" => "initialized from attributes", "written_on" => "2003-12-12 23:23"
+    })
+
+    assert_equal("initialized from attributes", topic.title)
+  end
+
+  def test_initialize_with_invalid_attribute
+    Topic.new({ "title" => "test",
+      "last_read(1i)" => "2005", "last_read(2i)" => "2", "last_read(3i)" => "31"})
+  rescue ActiveRecord::MultiparameterAssignmentErrors => ex
+    assert_equal(1, ex.errors.size)
+    assert_equal("last_read", ex.errors[0].attribute)
+  end
+
+  def test_create_after_initialize_without_block
+    cb = CustomBulb.create(:name => 'Dude')
+    assert_equal('Dude', cb.name)
+    assert_equal(true, cb.frickinawesome)
+  end
+
+  def test_create_after_initialize_with_block
+    cb = CustomBulb.create {|c| c.name = 'Dude' }
+    assert_equal('Dude', cb.name)
+    assert_equal(true, cb.frickinawesome)
+  end
+
+  def test_create_after_initialize_with_array_param
+    cbs = CustomBulb.create([{ name: 'Dude' }, { name: 'Bob' }])
+    assert_equal 'Dude', cbs[0].name
+    assert_equal 'Bob', cbs[1].name
+    assert cbs[0].frickinawesome
+    assert !cbs[1].frickinawesome
+  end
+
+  def test_load
+    topics = Topic.all.merge!(:order => 'id').to_a
+    assert_equal(5, topics.size)
+    assert_equal(topics(:first).title, topics.first.title)
+  end
+
+  def test_load_with_condition
+    topics = Topic.all.merge!(:where => "author_name = 'Mary'").to_a
+
+    assert_equal(1, topics.size)
+    assert_equal(topics(:second).title, topics.first.title)
+  end
+
+  GUESSED_CLASSES = [Category, Smarts, CreditCard, CreditCard::PinNumber, CreditCard::PinNumber::CvvCode, CreditCard::SubPinNumber, CreditCard::Brand, MasterCreditCard]
+
+  def test_table_name_guesses
+    assert_equal "topics", Topic.table_name
+
+    assert_equal "categories", Category.table_name
+    assert_equal "smarts", Smarts.table_name
+    assert_equal "credit_cards", CreditCard.table_name
+    assert_equal "credit_card_pin_numbers", CreditCard::PinNumber.table_name
+    assert_equal "credit_card_pin_number_cvv_codes", CreditCard::PinNumber::CvvCode.table_name
+    assert_equal "credit_card_pin_numbers", CreditCard::SubPinNumber.table_name
+    assert_equal "categories", CreditCard::Brand.table_name
+    assert_equal "master_credit_cards", MasterCreditCard.table_name
+  ensure
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_singular_table_name_guesses
+    ActiveRecord::Base.pluralize_table_names = false
+    GUESSED_CLASSES.each(&:reset_table_name)
+
+    assert_equal "category", Category.table_name
+    assert_equal "smarts", Smarts.table_name
+    assert_equal "credit_card", CreditCard.table_name
+    assert_equal "credit_card_pin_number", CreditCard::PinNumber.table_name
+    assert_equal "credit_card_pin_number_cvv_code", CreditCard::PinNumber::CvvCode.table_name
+    assert_equal "credit_card_pin_number", CreditCard::SubPinNumber.table_name
+    assert_equal "category", CreditCard::Brand.table_name
+    assert_equal "master_credit_card", MasterCreditCard.table_name
+  ensure
+    ActiveRecord::Base.pluralize_table_names = true
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_table_name_guesses_with_prefixes_and_suffixes
+    ActiveRecord::Base.table_name_prefix = "test_"
+    Category.reset_table_name
+    assert_equal "test_categories", Category.table_name
+    ActiveRecord::Base.table_name_suffix = "_test"
+    Category.reset_table_name
+    assert_equal "test_categories_test", Category.table_name
+    ActiveRecord::Base.table_name_prefix = ""
+    Category.reset_table_name
+    assert_equal "categories_test", Category.table_name
+    ActiveRecord::Base.table_name_suffix = ""
+    Category.reset_table_name
+    assert_equal "categories", Category.table_name
+  ensure
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_singular_table_name_guesses_with_prefixes_and_suffixes
+    ActiveRecord::Base.pluralize_table_names = false
+
+    ActiveRecord::Base.table_name_prefix = "test_"
+    Category.reset_table_name
+    assert_equal "test_category", Category.table_name
+    ActiveRecord::Base.table_name_suffix = "_test"
+    Category.reset_table_name
+    assert_equal "test_category_test", Category.table_name
+    ActiveRecord::Base.table_name_prefix = ""
+    Category.reset_table_name
+    assert_equal "category_test", Category.table_name
+    ActiveRecord::Base.table_name_suffix = ""
+    Category.reset_table_name
+    assert_equal "category", Category.table_name
+  ensure
+    ActiveRecord::Base.pluralize_table_names = true
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_table_name_guesses_with_inherited_prefixes_and_suffixes
+    GUESSED_CLASSES.each(&:reset_table_name)
+
+    CreditCard.table_name_prefix = "test_"
+    CreditCard.reset_table_name
+    Category.reset_table_name
+    assert_equal "test_credit_cards", CreditCard.table_name
+    assert_equal "categories", Category.table_name
+    CreditCard.table_name_suffix = "_test"
+    CreditCard.reset_table_name
+    Category.reset_table_name
+    assert_equal "test_credit_cards_test", CreditCard.table_name
+    assert_equal "categories", Category.table_name
+    CreditCard.table_name_prefix = ""
+    CreditCard.reset_table_name
+    Category.reset_table_name
+    assert_equal "credit_cards_test", CreditCard.table_name
+    assert_equal "categories", Category.table_name
+    CreditCard.table_name_suffix = ""
+    CreditCard.reset_table_name
+    Category.reset_table_name
+    assert_equal "credit_cards", CreditCard.table_name
+    assert_equal "categories", Category.table_name
+  ensure
+    CreditCard.table_name_prefix = ""
+    CreditCard.table_name_suffix = ""
+    GUESSED_CLASSES.each(&:reset_table_name)
+  end
+
+  def test_singular_table_name_guesses_for_individual_table
+    Post.pluralize_table_names = false
+    Post.reset_table_name
+    assert_equal "post", Post.table_name
+    assert_equal "categories", Category.table_name
+  ensure
+    Post.pluralize_table_names = true
+    Post.reset_table_name
+  end
+
+  if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+    def test_update_all_with_order_and_limit
+      assert_equal 1, Topic.limit(1).order('id DESC').update_all(:content => 'bulk updated!')
+    end
+  end
+
+  def test_null_fields
+    assert_nil Topic.find(1).parent_id
+    assert_nil Topic.create("title" => "Hey you").parent_id
+  end
+
+  def test_default_values
+    topic = Topic.new
+    assert topic.approved?
+    assert_nil topic.written_on
+    assert_nil topic.bonus_time
+    assert_nil topic.last_read
+
+    topic.save
+
+    topic = Topic.find(topic.id)
+    assert topic.approved?
+    assert_nil topic.last_read
+
+    # Oracle has some funky default handling, so it requires a bit of
+    # extra testing. See ticket #2788.
+    if current_adapter?(:OracleAdapter)
+      test = TestOracleDefault.new
+      assert_equal "X", test.test_char
+      assert_equal "hello", test.test_string
+      assert_equal 3, test.test_int
+    end
+  end
+
+  # Oracle does not have a TIME datatype.
+  unless current_adapter?(:OracleAdapter)
+    def test_utc_as_time_zone
+      with_timezone_config default: :utc do
+        attributes = { "bonus_time" => "5:42:00AM" }
+        topic = Topic.find(1)
+        topic.attributes = attributes
+        assert_equal Time.utc(2000, 1, 1, 5, 42, 0), topic.bonus_time
+      end
+    end
+
+    def test_utc_as_time_zone_and_new
+      with_timezone_config default: :utc do
+        attributes = { "bonus_time(1i)"=>"2000",
+          "bonus_time(2i)"=>"1",
+          "bonus_time(3i)"=>"1",
+          "bonus_time(4i)"=>"10",
+          "bonus_time(5i)"=>"35",
+          "bonus_time(6i)"=>"50" }
+        topic = Topic.new(attributes)
+        assert_equal Time.utc(2000, 1, 1, 10, 35, 50), topic.bonus_time
+      end
+    end
+  end
+
+  def test_default_values_on_empty_strings
+    topic = Topic.new
+    topic.approved  = nil
+    topic.last_read = nil
+
+    topic.save
+
+    topic = Topic.find(topic.id)
+    assert_nil topic.last_read
+
+    assert_nil topic.approved
+  end
+
+  def test_equality
+    assert_equal Topic.find(1), Topic.find(2).topic
+  end
+
+  def test_find_by_slug
+    assert_equal Topic.find('1-meowmeow'), Topic.find(1)
+  end
+
+  def test_find_by_slug_with_array
+    assert_equal Topic.find(['1-meowmeow', '2-hello']), Topic.find([1, 2])
+  end
+
+  def test_equality_of_new_records
+    assert_not_equal Topic.new, Topic.new
+    assert_equal false, Topic.new == Topic.new
+  end
+
+  def test_equality_of_destroyed_records
+    topic_1 = Topic.new(:title => 'test_1')
+    topic_1.save
+    topic_2 = Topic.find(topic_1.id)
+    topic_1.destroy
+    assert_equal topic_1, topic_2
+    assert_equal topic_2, topic_1
+  end
+
+  def test_equality_with_blank_ids
+    one = Subscriber.new(:id => '')
+    two = Subscriber.new(:id => '')
+    assert_equal one, two
+  end
+
+  def test_equality_of_relation_and_collection_proxy
+    car = Car.create!
+    car.bulbs.build
+    car.save
+
+    assert car.bulbs == Bulb.where(car_id: car.id), 'CollectionProxy should be comparable with Relation'
+    assert Bulb.where(car_id: car.id) == car.bulbs, 'Relation should be comparable with CollectionProxy'
+  end
+
+  def test_equality_of_relation_and_array
+    car = Car.create!
+    car.bulbs.build
+    car.save
+
+    assert Bulb.where(car_id: car.id) == car.bulbs.to_a, 'Relation should be comparable with Array'
+  end
+
+  def test_equality_of_relation_and_association_relation
+    car = Car.create!
+    car.bulbs.build
+    car.save
+
+    assert_equal Bulb.where(car_id: car.id), car.bulbs.includes(:car), 'Relation should be comparable with AssociationRelation'
+    assert_equal car.bulbs.includes(:car), Bulb.where(car_id: car.id), 'AssociationRelation should be comparable with Relation'
+  end
+
+  def test_equality_of_collection_proxy_and_association_relation
+    car = Car.create!
+    car.bulbs.build
+    car.save
+
+    assert_equal car.bulbs, car.bulbs.includes(:car), 'CollectionProxy should be comparable with AssociationRelation'
+    assert_equal car.bulbs.includes(:car), car.bulbs, 'AssociationRelation should be comparable with CollectionProxy'
+  end
+
+  def test_hashing
+    assert_equal [ Topic.find(1) ], [ Topic.find(2).topic ] & [ Topic.find(1) ]
+  end
+
+  def test_successful_comparison_of_like_class_records
+    topic_1 = Topic.create!
+    topic_2 = Topic.create!
+
+    assert_equal [topic_2, topic_1].sort, [topic_1, topic_2]
+  end
+
+  def test_failed_comparison_of_unlike_class_records
+    assert_raises ArgumentError do
+      [ topics(:first), posts(:welcome) ].sort
+    end
+  end
+
+  def test_create_without_prepared_statement
+    topic = Topic.connection.unprepared_statement do
+      Topic.create(:title => 'foo')
+    end
+
+    assert_equal topic, Topic.find(topic.id)
+  end
+
+  def test_destroy_without_prepared_statement
+    topic = Topic.create(title: 'foo')
+    Topic.connection.unprepared_statement do
+      Topic.find(topic.id).destroy
+    end
+
+    assert_equal nil, Topic.find_by_id(topic.id)
+  end
+
+  def test_comparison_with_different_objects
+    topic = Topic.create
+    category = Category.create(:name => "comparison")
+    assert_nil topic <=> category
+  end
+
+  def test_comparison_with_different_objects_in_array
+    topic = Topic.create
+    assert_raises(ArgumentError) do
+      [1, topic].sort
+    end
+  end
+
+  def test_readonly_attributes
+    assert_equal Set.new([ 'title' , 'comments_count' ]), ReadonlyTitlePost.readonly_attributes
+
+    post = ReadonlyTitlePost.create(:title => "cannot change this", :body => "changeable")
+    post.reload
+    assert_equal "cannot change this", post.title
+
+    post.update(title: "try to change", body: "changed")
+    post.reload
+    assert_equal "cannot change this", post.title
+    assert_equal "changed", post.body
+  end
+
+  def test_unicode_column_name
+    Weird.reset_column_information
+    weird = Weird.create(:なまえ => 'たこ焼き仮面')
+    assert_equal 'たこ焼き仮面', weird.なまえ
+  end
+
+  unless current_adapter?(:PostgreSQLAdapter)
+    def test_respect_internal_encoding
+      old_default_internal = Encoding.default_internal
+      silence_warnings { Encoding.default_internal = "EUC-JP" }
+
+      Weird.reset_column_information
+
+      assert_equal ["EUC-JP"], Weird.columns.map {|c| c.name.encoding.name }.uniq
+    ensure
+      silence_warnings { Encoding.default_internal = old_default_internal }
+      Weird.reset_column_information
+    end
+  end
+
+  def test_non_valid_identifier_column_name
+    weird = Weird.create('a$b' => 'value')
+    weird.reload
+    assert_equal 'value', weird.send('a$b')
+    assert_equal 'value', weird.read_attribute('a$b')
+
+    weird.update_columns('a$b' => 'value2')
+    weird.reload
+    assert_equal 'value2', weird.send('a$b')
+    assert_equal 'value2', weird.read_attribute('a$b')
+  end
+
+  def test_group_weirds_by_from
+    Weird.create('a$b' => 'value', :from => 'aaron')
+    count = Weird.group(Weird.arel_table[:from]).count
+    assert_equal 1, count['aaron']
+  end
+
+  def test_attributes_on_dummy_time
+    # Oracle does not have a TIME datatype.
+    return true if current_adapter?(:OracleAdapter)
+
+    with_timezone_config default: :local do
+      attributes = {
+        "bonus_time" => "5:42:00AM"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2000, 1, 1, 5, 42, 0), topic.bonus_time
+    end
+  end
+
+  def test_attributes_on_dummy_time_with_invalid_time
+    # Oracle does not have a TIME datatype.
+    return true if current_adapter?(:OracleAdapter)
+
+    attributes = {
+      "bonus_time" => "not a time"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.bonus_time
+  end
+
+  def test_boolean
+    b_nil = Boolean.create({ "value" => nil })
+    nil_id = b_nil.id
+    b_false = Boolean.create({ "value" => false })
+    false_id = b_false.id
+    b_true = Boolean.create({ "value" => true })
+    true_id = b_true.id
+
+    b_nil = Boolean.find(nil_id)
+    assert_nil b_nil.value
+    b_false = Boolean.find(false_id)
+    assert !b_false.value?
+    b_true = Boolean.find(true_id)
+    assert b_true.value?
+  end
+
+  def test_boolean_without_questionmark
+    b_true = Boolean.create({ "value" => true })
+    true_id = b_true.id
+
+    subclass   = Class.new(Boolean).find true_id
+    superclass = Boolean.find true_id
+
+    assert_equal superclass.read_attribute(:has_fun), subclass.read_attribute(:has_fun)
+  end
+
+  def test_boolean_cast_from_string
+    b_blank = Boolean.create({ "value" => "" })
+    blank_id = b_blank.id
+    b_false = Boolean.create({ "value" => "0" })
+    false_id = b_false.id
+    b_true = Boolean.create({ "value" => "1" })
+    true_id = b_true.id
+
+    b_blank = Boolean.find(blank_id)
+    assert_nil b_blank.value
+    b_false = Boolean.find(false_id)
+    assert !b_false.value?
+    b_true = Boolean.find(true_id)
+    assert b_true.value?
+  end
+
+  def test_new_record_returns_boolean
+    assert_equal false, Topic.new.persisted?
+    assert_equal true, Topic.find(1).persisted?
+  end
+
+  def test_dup
+    topic = Topic.find(1)
+    duped_topic = nil
+    assert_nothing_raised { duped_topic = topic.dup }
+    assert_equal topic.title, duped_topic.title
+    assert !duped_topic.persisted?
+
+    # test if the attributes have been duped
+    topic.title = "a"
+    duped_topic.title = "b"
+    assert_equal "a", topic.title
+    assert_equal "b", duped_topic.title
+
+    # test if the attribute values have been duped
+    duped_topic = topic.dup
+    duped_topic.title.replace "c"
+    assert_equal "a", topic.title
+
+    # test if attributes set as part of after_initialize are duped correctly
+    assert_equal topic.author_email_address, duped_topic.author_email_address
+
+    # test if saved clone object differs from original
+    duped_topic.save
+    assert duped_topic.persisted?
+    assert_not_equal duped_topic.id, topic.id
+
+    duped_topic.reload
+    assert_equal("c", duped_topic.title)
+  end
+
+  DeveloperSalary = Struct.new(:amount)
+  def test_dup_with_aggregate_of_same_name_as_attribute
+    developer_with_aggregate = Class.new(ActiveRecord::Base) do
+      self.table_name = 'developers'
+      composed_of :salary, :class_name => 'BasicsTest::DeveloperSalary', :mapping => [%w(salary amount)]
+    end
+
+    dev = developer_with_aggregate.find(1)
+    assert_kind_of DeveloperSalary, dev.salary
+
+    dup = nil
+    assert_nothing_raised { dup = dev.dup }
+    assert_kind_of DeveloperSalary, dup.salary
+    assert_equal dev.salary.amount, dup.salary.amount
+    assert !dup.persisted?
+
+    # test if the attributes have been dupd
+    original_amount = dup.salary.amount
+    dev.salary.amount = 1
+    assert_equal original_amount, dup.salary.amount
+
+    assert dup.save
+    assert dup.persisted?
+    assert_not_equal dup.id, dev.id
+  end
+
+  def test_dup_does_not_copy_associations
+    author = authors(:david)
+    assert_not_equal [], author.posts
+    author.send(:clear_association_cache)
+
+    author_dup = author.dup
+    assert_equal [], author_dup.posts
+  end
+
+  def test_clone_preserves_subtype
+    clone = nil
+    assert_nothing_raised { clone = Company.find(3).clone }
+    assert_kind_of Client, clone
+  end
+
+  def test_clone_of_new_object_with_defaults
+    developer = Developer.new
+    assert !developer.name_changed?
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.clone
+    assert !cloned_developer.name_changed?
+    assert !cloned_developer.salary_changed?
+  end
+
+  def test_clone_of_new_object_marks_attributes_as_dirty
+    developer = Developer.new :name => 'Bjorn', :salary => 100000
+    assert developer.name_changed?
+    assert developer.salary_changed?
+
+    cloned_developer = developer.clone
+    assert cloned_developer.name_changed?
+    assert cloned_developer.salary_changed?
+  end
+
+  def test_clone_of_new_object_marks_as_dirty_only_changed_attributes
+    developer = Developer.new :name => 'Bjorn'
+    assert developer.name_changed?            # obviously
+    assert !developer.salary_changed?         # attribute has non-nil default value, so treated as not changed
+
+    cloned_developer = developer.clone
+    assert cloned_developer.name_changed?
+    assert !cloned_developer.salary_changed?  # ... and cloned instance should behave same
+  end
+
+  def test_dup_of_saved_object_marks_attributes_as_dirty
+    developer = Developer.create! :name => 'Bjorn', :salary => 100000
+    assert !developer.name_changed?
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.dup
+    assert cloned_developer.name_changed?     # both attributes differ from defaults
+    assert cloned_developer.salary_changed?
+  end
+
+  def test_dup_of_saved_object_marks_as_dirty_only_changed_attributes
+    developer = Developer.create! :name => 'Bjorn'
+    assert !developer.name_changed?           # both attributes of saved object should be treated as not changed
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.dup
+    assert cloned_developer.name_changed?     # ... but on cloned object should be
+    assert !cloned_developer.salary_changed?  # ... BUT salary has non-nil default which should be treated as not changed on cloned instance
+  end
+
+  def test_bignum
+    company = Company.find(1)
+    company.rating = 2147483647
+    company.save
+    company = Company.find(1)
+    assert_equal 2147483647, company.rating
+  end
+
+  # TODO: extend defaults tests to other databases!
+  if current_adapter?(:PostgreSQLAdapter)
+    def test_default
+      with_timezone_config default: :local do
+        default = Default.new
+
+        # fixed dates / times
+        assert_equal Date.new(2004, 1, 1), default.fixed_date
+        assert_equal Time.local(2004, 1,1,0,0,0,0), default.fixed_time
+
+        # char types
+        assert_equal 'Y', default.char1
+        assert_equal 'a varchar field', default.char2
+        assert_equal 'a text field', default.char3
+      end
+    end
+
+    class Geometric < ActiveRecord::Base; end
+    def test_geometric_content
+
+      # accepted format notes:
+      # ()'s aren't required
+      # values can be a mix of float or integer
+
+      g = Geometric.new(
+        :a_point        => '(5.0, 6.1)',
+        #:a_line         => '((2.0, 3), (5.5, 7.0))' # line type is currently unsupported in postgresql
+        :a_line_segment => '(2.0, 3), (5.5, 7.0)',
+        :a_box          => '2.0, 3, 5.5, 7.0',
+        :a_path         => '[(2.0, 3), (5.5, 7.0), (8.5, 11.0)]',  # [ ] is an open path
+        :a_polygon      => '((2.0, 3), (5.5, 7.0), (8.5, 11.0))',
+        :a_circle       => '<(5.3, 10.4), 2>'
+      )
+
+      assert g.save
+
+      # Reload and check that we have all the geometric attributes.
+      h = Geometric.find(g.id)
+
+      assert_equal [5.0, 6.1], h.a_point
+      assert_equal '[(2,3),(5.5,7)]', h.a_line_segment
+      assert_equal '(5.5,7),(2,3)', h.a_box   # reordered to store upper right corner then bottom left corner
+      assert_equal '[(2,3),(5.5,7),(8.5,11)]', h.a_path
+      assert_equal '((2,3),(5.5,7),(8.5,11))', h.a_polygon
+      assert_equal '<(5.3,10.4),2>', h.a_circle
+
+      # use a geometric function to test for an open path
+      objs = Geometric.find_by_sql ["select isopen(a_path) from geometrics where id = ?", g.id]
+
+      assert_equal true, objs[0].isopen
+
+      # test alternate formats when defining the geometric types
+
+      g = Geometric.new(
+        :a_point        => '5.0, 6.1',
+        #:a_line         => '((2.0, 3), (5.5, 7.0))' # line type is currently unsupported in postgresql
+        :a_line_segment => '((2.0, 3), (5.5, 7.0))',
+        :a_box          => '(2.0, 3), (5.5, 7.0)',
+        :a_path         => '((2.0, 3), (5.5, 7.0), (8.5, 11.0))',  # ( ) is a closed path
+        :a_polygon      => '2.0, 3, 5.5, 7.0, 8.5, 11.0',
+        :a_circle       => '((5.3, 10.4), 2)'
+      )
+
+      assert g.save
+
+      # Reload and check that we have all the geometric attributes.
+      h = Geometric.find(g.id)
+
+      assert_equal [5.0, 6.1], h.a_point
+      assert_equal '[(2,3),(5.5,7)]', h.a_line_segment
+      assert_equal '(5.5,7),(2,3)', h.a_box   # reordered to store upper right corner then bottom left corner
+      assert_equal '((2,3),(5.5,7),(8.5,11))', h.a_path
+      assert_equal '((2,3),(5.5,7),(8.5,11))', h.a_polygon
+      assert_equal '<(5.3,10.4),2>', h.a_circle
+
+      # use a geometric function to test for an closed path
+      objs = Geometric.find_by_sql ["select isclosed(a_path) from geometrics where id = ?", g.id]
+
+      assert_equal true, objs[0].isclosed
+
+      # test native ruby formats when defining the geometric types
+      g = Geometric.new(
+        :a_point        => [5.0, 6.1],
+        #:a_line         => '((2.0, 3), (5.5, 7.0))' # line type is currently unsupported in postgresql
+        :a_line_segment => '((2.0, 3), (5.5, 7.0))',
+        :a_box          => '(2.0, 3), (5.5, 7.0)',
+        :a_path         => '((2.0, 3), (5.5, 7.0), (8.5, 11.0))',  # ( ) is a closed path
+        :a_polygon      => '2.0, 3, 5.5, 7.0, 8.5, 11.0',
+        :a_circle       => '((5.3, 10.4), 2)'
+      )
+
+      assert g.save
+
+      # Reload and check that we have all the geometric attributes.
+      h = Geometric.find(g.id)
+
+      assert_equal [5.0, 6.1], h.a_point
+      assert_equal '[(2,3),(5.5,7)]', h.a_line_segment
+      assert_equal '(5.5,7),(2,3)', h.a_box   # reordered to store upper right corner then bottom left corner
+      assert_equal '((2,3),(5.5,7),(8.5,11))', h.a_path
+      assert_equal '((2,3),(5.5,7),(8.5,11))', h.a_polygon
+      assert_equal '<(5.3,10.4),2>', h.a_circle
+    end
+  end
+
+  class NumericData < ActiveRecord::Base
+    self.table_name = 'numeric_data'
+
+    attribute :world_population, Type::Integer.new
+    attribute :my_house_population, Type::Integer.new
+    attribute :atoms_in_universe, Type::Integer.new
+  end
+
+  def test_big_decimal_conditions
+    m = NumericData.new(
+      :bank_balance => 1586.43,
+      :big_bank_balance => BigDecimal("1000234000567.95"),
+      :world_population => 6000000000,
+      :my_house_population => 3
+    )
+    assert m.save
+    assert_equal 0, NumericData.where("bank_balance > ?", 2000.0).count
+  end
+
+  def test_numeric_fields
+    m = NumericData.new(
+      :bank_balance => 1586.43,
+      :big_bank_balance => BigDecimal("1000234000567.95"),
+      :world_population => 6000000000,
+      :my_house_population => 3
+    )
+    assert m.save
+
+    m1 = NumericData.find(m.id)
+    assert_not_nil m1
+
+    # As with migration_test.rb, we should make world_population >= 2**62
+    # to cover 64-bit platforms and test it is a Bignum, but the main thing
+    # is that it's an Integer.
+    assert_kind_of Integer, m1.world_population
+    assert_equal 6000000000, m1.world_population
+
+    assert_kind_of Fixnum, m1.my_house_population
+    assert_equal 3, m1.my_house_population
+
+    assert_kind_of BigDecimal, m1.bank_balance
+    assert_equal BigDecimal("1586.43"), m1.bank_balance
+
+    assert_kind_of BigDecimal, m1.big_bank_balance
+    assert_equal BigDecimal("1000234000567.95"), m1.big_bank_balance
+  end
+
+  def test_auto_id
+    auto = AutoId.new
+    auto.save
+    assert(auto.id > 0)
+  end
+
+  def test_sql_injection_via_find
+    assert_raise(ActiveRecord::RecordNotFound, ActiveRecord::StatementInvalid) do
+      Topic.find("123456 OR id > 0")
+    end
+  end
+
+  def test_column_name_properly_quoted
+    col_record = ColumnName.new
+    col_record.references = 40
+    assert col_record.save
+    col_record.references = 41
+    assert col_record.save
+    assert_not_nil c2 = ColumnName.find(col_record.id)
+    assert_equal(41, c2.references)
+  end
+
+  def test_quoting_arrays
+    replies = Reply.all.merge!(:where => [ "id IN (?)", topics(:first).replies.collect(&:id) ]).to_a
+    assert_equal topics(:first).replies.size, replies.size
+
+    replies = Reply.all.merge!(:where => [ "id IN (?)", [] ]).to_a
+    assert_equal 0, replies.size
+  end
+
+  def test_quote
+    author_name = "\\ \001 ' \n \\n \""
+    topic = Topic.create('author_name' => author_name)
+    assert_equal author_name, Topic.find(topic.id).author_name
+  end
+
+  def test_toggle_attribute
+    assert !topics(:first).approved?
+    topics(:first).toggle!(:approved)
+    assert topics(:first).approved?
+    topic = topics(:first)
+    topic.toggle(:approved)
+    assert !topic.approved?
+    topic.reload
+    assert topic.approved?
+  end
+
+  def test_reload
+    t1 = Topic.find(1)
+    t2 = Topic.find(1)
+    t1.title = "something else"
+    t1.save
+    t2.reload
+    assert_equal t1.title, t2.title
+  end
+
+  def test_reload_with_exclusive_scope
+    dev = DeveloperCalledDavid.first
+    dev.update!(name: "NotDavid" )
+    assert_equal dev, dev.reload
+  end
+
+  def test_switching_between_table_name
+    assert_difference("GoodJoke.count") do
+      Joke.table_name = "cold_jokes"
+      Joke.create
+
+      Joke.table_name = "funny_jokes"
+      Joke.create
+    end
+  end
+
+  def test_clear_cash_when_setting_table_name
+    Joke.table_name = "cold_jokes"
+    before_columns = Joke.columns
+    before_seq     = Joke.sequence_name
+
+    Joke.table_name = "funny_jokes"
+    after_columns = Joke.columns
+    after_seq     = Joke.sequence_name
+
+    assert_not_equal before_columns, after_columns
+    assert_not_equal before_seq, after_seq unless before_seq.nil? && after_seq.nil?
+  end
+
+  def test_dont_clear_sequence_name_when_setting_explicitly
+    Joke.sequence_name = "black_jokes_seq"
+    Joke.table_name    = "cold_jokes"
+    before_seq         = Joke.sequence_name
+
+    Joke.table_name    = "funny_jokes"
+    after_seq          = Joke.sequence_name
+
+    assert_equal before_seq, after_seq unless before_seq.nil? && after_seq.nil?
+  ensure
+    Joke.reset_sequence_name
+  end
+
+  def test_dont_clear_inheritance_column_when_setting_explicitly
+    Joke.inheritance_column = "my_type"
+    before_inherit = Joke.inheritance_column
+
+    Joke.reset_column_information
+    after_inherit = Joke.inheritance_column
+
+    assert_equal before_inherit, after_inherit unless before_inherit.blank? && after_inherit.blank?
+  end
+
+  def test_set_table_name_symbol_converted_to_string
+    Joke.table_name = :cold_jokes
+    assert_equal 'cold_jokes', Joke.table_name
+  end
+
+  def test_quoted_table_name_after_set_table_name
+    klass = Class.new(ActiveRecord::Base)
+
+    klass.table_name = "foo"
+    assert_equal "foo", klass.table_name
+    assert_equal klass.connection.quote_table_name("foo"), klass.quoted_table_name
+
+    klass.table_name = "bar"
+    assert_equal "bar", klass.table_name
+    assert_equal klass.connection.quote_table_name("bar"), klass.quoted_table_name
+  end
+
+  def test_set_table_name_with_inheritance
+    k = Class.new( ActiveRecord::Base )
+    def k.name; "Foo"; end
+    def k.table_name; super + "ks"; end
+    assert_equal "foosks", k.table_name
+  end
+
+  def test_sequence_name_with_abstract_class
+    ak = Class.new(ActiveRecord::Base)
+    ak.abstract_class = true
+    k = Class.new(ak)
+    k.table_name = "projects"
+    orig_name = k.sequence_name
+    skip "sequences not supported by db" unless orig_name
+    assert_equal k.reset_sequence_name, orig_name
+  end
+
+  def test_count_with_join
+    res = Post.count_by_sql "SELECT COUNT(*) FROM posts LEFT JOIN comments ON posts.id=comments.post_id WHERE posts.#{QUOTED_TYPE} = 'Post'"
+
+    res2 = Post.where("posts.#{QUOTED_TYPE} = 'Post'").joins("LEFT JOIN comments ON posts.id=comments.post_id").count
+    assert_equal res, res2
+
+    res3 = nil
+    assert_nothing_raised do
+      res3 = Post.where("posts.#{QUOTED_TYPE} = 'Post'").joins("LEFT JOIN comments ON posts.id=comments.post_id").count
+    end
+    assert_equal res, res3
+
+    res4 = Post.count_by_sql "SELECT COUNT(p.id) FROM posts p, comments co WHERE p.#{QUOTED_TYPE} = 'Post' AND p.id=co.post_id"
+    res5 = nil
+    assert_nothing_raised do
+      res5 = Post.where("p.#{QUOTED_TYPE} = 'Post' AND p.id=co.post_id").joins("p, comments co").select("p.id").count
+    end
+
+    assert_equal res4, res5
+
+    res6 = Post.count_by_sql "SELECT COUNT(DISTINCT p.id) FROM posts p, comments co WHERE p.#{QUOTED_TYPE} = 'Post' AND p.id=co.post_id"
+    res7 = nil
+    assert_nothing_raised do
+      res7 = Post.where("p.#{QUOTED_TYPE} = 'Post' AND p.id=co.post_id").joins("p, comments co").select("p.id").distinct.count
+    end
+    assert_equal res6, res7
+  end
+
+  def test_no_limit_offset
+    assert_nothing_raised do
+      Developer.all.merge!(:offset => 2).to_a
+    end
+  end
+
+  def test_find_last
+    last  = Developer.last
+    assert_equal last, Developer.all.merge!(:order => 'id desc').first
+  end
+
+  def test_last
+    assert_equal Developer.all.merge!(:order => 'id desc').first, Developer.last
+  end
+
+  def test_all
+    developers = Developer.all
+    assert_kind_of ActiveRecord::Relation, developers
+    assert_equal Developer.all, developers
+  end
+
+  def test_all_with_conditions
+    assert_equal Developer.all.merge!(:order => 'id desc').to_a, Developer.order('id desc').to_a
+  end
+
+  def test_find_ordered_last
+    last  = Developer.all.merge!(:order => 'developers.salary ASC').last
+    assert_equal last, Developer.all.merge!(:order => 'developers.salary ASC').to_a.last
+  end
+
+  def test_find_reverse_ordered_last
+    last  = Developer.all.merge!(:order => 'developers.salary DESC').last
+    assert_equal last, Developer.all.merge!(:order => 'developers.salary DESC').to_a.last
+  end
+
+  def test_find_multiple_ordered_last
+    last  = Developer.all.merge!(:order => 'developers.name, developers.salary DESC').last
+    assert_equal last, Developer.all.merge!(:order => 'developers.name, developers.salary DESC').to_a.last
+  end
+
+  def test_find_keeps_multiple_order_values
+    combined = Developer.all.merge!(:order => 'developers.name, developers.salary').to_a
+    assert_equal combined, Developer.all.merge!(:order => ['developers.name', 'developers.salary']).to_a
+  end
+
+  def test_find_keeps_multiple_group_values
+    combined = Developer.all.merge!(:group => 'developers.name, developers.salary, developers.id, developers.created_at, developers.updated_at, developers.created_on, developers.updated_on').to_a
+    assert_equal combined, Developer.all.merge!(:group => ['developers.name', 'developers.salary', 'developers.id', 'developers.created_at', 'developers.updated_at', 'developers.created_on', 'developers.updated_on']).to_a
+  end
+
+  def test_find_symbol_ordered_last
+    last  = Developer.all.merge!(:order => :salary).last
+    assert_equal last, Developer.all.merge!(:order => :salary).to_a.last
+  end
+
+  def test_abstract_class
+    assert !ActiveRecord::Base.abstract_class?
+    assert LoosePerson.abstract_class?
+    assert !LooseDescendant.abstract_class?
+  end
+
+  def test_abstract_class_table_name
+    assert_nil AbstractCompany.table_name
+  end
+
+  def test_descends_from_active_record
+    assert !ActiveRecord::Base.descends_from_active_record?
+
+    # Abstract subclass of AR::Base.
+    assert LoosePerson.descends_from_active_record?
+
+    # Concrete subclass of an abstract class.
+    assert LooseDescendant.descends_from_active_record?
+
+    # Concrete subclass of AR::Base.
+    assert TightPerson.descends_from_active_record?
+
+    # Concrete subclass of a concrete class but has no type column.
+    assert TightDescendant.descends_from_active_record?
+
+    # Concrete subclass of AR::Base.
+    assert Post.descends_from_active_record?
+
+    # Abstract subclass of a concrete class which has a type column.
+    # This is pathological, as you'll never have Sub < Abstract < Concrete.
+    assert !StiPost.descends_from_active_record?
+
+    # Concrete subclasses an abstract class which has a type column.
+    assert !SubStiPost.descends_from_active_record?
+  end
+
+  def test_find_on_abstract_base_class_doesnt_use_type_condition
+    old_class = LooseDescendant
+    Object.send :remove_const, :LooseDescendant
+
+    descendant = old_class.create! :first_name => 'bob'
+    assert_not_nil LoosePerson.find(descendant.id), "Should have found instance of LooseDescendant when finding abstract LoosePerson: #{descendant.inspect}"
+  ensure
+    unless Object.const_defined?(:LooseDescendant)
+      Object.const_set :LooseDescendant, old_class
+    end
+  end
+
+  def test_assert_queries
+    query = lambda { ActiveRecord::Base.connection.execute 'select count(*) from developers' }
+    assert_queries(2) { 2.times { query.call } }
+    assert_queries 1, &query
+    assert_no_queries { assert true }
+  end
+
+  def test_benchmark_with_log_level
+    original_logger = ActiveRecord::Base.logger
+    log = StringIO.new
+    ActiveRecord::Base.logger = ActiveSupport::Logger.new(log)
+    ActiveRecord::Base.logger.level = Logger::WARN
+    ActiveRecord::Base.benchmark("Debug Topic Count", :level => :debug) { Topic.count }
+    ActiveRecord::Base.benchmark("Warn Topic Count",  :level => :warn)  { Topic.count }
+    ActiveRecord::Base.benchmark("Error Topic Count", :level => :error) { Topic.count }
+    assert_no_match(/Debug Topic Count/, log.string)
+    assert_match(/Warn Topic Count/, log.string)
+    assert_match(/Error Topic Count/, log.string)
+  ensure
+    ActiveRecord::Base.logger = original_logger
+  end
+
+  def test_benchmark_with_use_silence
+    original_logger = ActiveRecord::Base.logger
+    log = StringIO.new
+    ActiveRecord::Base.logger = ActiveSupport::Logger.new(log)
+    ActiveRecord::Base.benchmark("Logging", :level => :debug, :silence => false)  { ActiveRecord::Base.logger.debug "Quiet" }
+    assert_match(/Quiet/, log.string)
+  ensure
+    ActiveRecord::Base.logger = original_logger
+  end
+
+  def test_compute_type_success
+    assert_equal Author, ActiveRecord::Base.send(:compute_type, 'Author')
+  end
+
+  def test_compute_type_nonexistent_constant
+    e = assert_raises NameError do
+      ActiveRecord::Base.send :compute_type, 'NonexistentModel'
+    end
+    assert_equal 'uninitialized constant ActiveRecord::Base::NonexistentModel', e.message
+    assert_equal 'ActiveRecord::Base::NonexistentModel', e.name
+  end
+
+  def test_compute_type_no_method_error
+    ActiveSupport::Dependencies.stubs(:safe_constantize).raises(NoMethodError)
+    assert_raises NoMethodError do
+      ActiveRecord::Base.send :compute_type, 'InvalidModel'
+    end
+  end
+
+  def test_compute_type_on_undefined_method
+    error = nil
+    begin
+      Class.new(Author) do
+        alias_method :foo, :bar
+      end
+    rescue => e
+      error = e
+    end
+
+    ActiveSupport::Dependencies.stubs(:safe_constantize).raises(e)
+
+    exception = assert_raises NameError do
+      ActiveRecord::Base.send :compute_type, 'InvalidModel'
+    end
+    assert_equal error.message, exception.message
+  end
+
+  def test_compute_type_argument_error
+    ActiveSupport::Dependencies.stubs(:safe_constantize).raises(ArgumentError)
+    assert_raises ArgumentError do
+      ActiveRecord::Base.send :compute_type, 'InvalidModel'
+    end
+  end
+
+  def test_clear_cache!
+    # preheat cache
+    c1 = Post.connection.schema_cache.columns('posts')
+    ActiveRecord::Base.clear_cache!
+    c2 = Post.connection.schema_cache.columns('posts')
+    assert_not_equal c1, c2
+  end
+
+  def test_current_scope_is_reset
+    Object.const_set :UnloadablePost, Class.new(ActiveRecord::Base)
+    UnloadablePost.send(:current_scope=, UnloadablePost.all)
+
+    UnloadablePost.unloadable
+    assert_not_nil ActiveRecord::Scoping::ScopeRegistry.value_for(:current_scope, "UnloadablePost")
+    ActiveSupport::Dependencies.remove_unloadable_constants!
+    assert_nil ActiveRecord::Scoping::ScopeRegistry.value_for(:current_scope, "UnloadablePost")
+  ensure
+    Object.class_eval{ remove_const :UnloadablePost } if defined?(UnloadablePost)
+  end
+
+  def test_marshal_round_trip
+    expected = posts(:welcome)
+    marshalled = Marshal.dump(expected)
+    actual   = Marshal.load(marshalled)
+
+    assert_equal expected.attributes, actual.attributes
+  end
+
+  def test_marshal_new_record_round_trip
+    marshalled = Marshal.dump(Post.new)
+    post       = Marshal.load(marshalled)
+
+    assert post.new_record?, "should be a new record"
+  end
+
+  def test_marshalling_with_associations
+    post = Post.new
+    post.comments.build
+
+    marshalled = Marshal.dump(post)
+    post       = Marshal.load(marshalled)
+
+    assert_equal 1, post.comments.length
+  end
+
+  if Process.respond_to?(:fork) && !in_memory_db?
+    def test_marshal_between_processes
+      # Define a new model to ensure there are no caches
+      if self.class.const_defined?("Post", false)
+        flunk "there should be no post constant"
+      end
+
+      self.class.const_set("Post", Class.new(ActiveRecord::Base) {
+        has_many :comments
+      })
+
+      rd, wr = IO.pipe
+      rd.binmode
+      wr.binmode
+
+      ActiveRecord::Base.connection_handler.clear_all_connections!
+
+      fork do
+        rd.close
+        post = Post.new
+        post.comments.build
+        wr.write Marshal.dump(post)
+        wr.close
+      end
+
+      wr.close
+      assert Marshal.load rd.read
+      rd.close
+    end
+  end
+
+  def test_marshalling_new_record_round_trip_with_associations
+    post = Post.new
+    post.comments.build
+
+    post = Marshal.load(Marshal.dump(post))
+
+    assert post.new_record?, "should be a new record"
+  end
+
+  def test_attribute_names
+    assert_equal ["id", "type", "firm_id", "firm_name", "name", "client_of", "rating", "account_id", "description"],
+                 Company.attribute_names
+  end
+
+  def test_attribute_names_on_table_not_exists
+    assert_equal [], NonExistentTable.attribute_names
+  end
+
+  def test_attribute_names_on_abstract_class
+    assert_equal [], AbstractCompany.attribute_names
+  end
+
+  def test_touch_should_raise_error_on_a_new_object
+    company = Company.new(:rating => 1, :name => "37signals", :firm_name => "37signals")
+    assert_raises(ActiveRecord::ActiveRecordError) do
+      company.touch :updated_at
+    end
+  end
+
+  def test_uniq_delegates_to_scoped
+    scope = stub
+    Bird.stubs(:all).returns(mock(:uniq => scope))
+    assert_equal scope, Bird.uniq
+  end
+
+  def test_distinct_delegates_to_scoped
+    scope = stub
+    Bird.stubs(:all).returns(mock(:distinct => scope))
+    assert_equal scope, Bird.distinct
+  end
+
+  def test_table_name_with_2_abstract_subclasses
+    assert_equal "photos", Photo.table_name
+  end
+
+  def test_column_types_typecast
+    topic = Topic.first
+    assert_not_equal 't.lo', topic.author_name
+
+    attrs = topic.attributes.dup
+    attrs.delete 'id'
+
+    typecast = Class.new(ActiveRecord::Type::Value) {
+      def type_cast value
+        "t.lo"
+      end
+    }
+
+    types = { 'author_name' => typecast.new }
+    topic = Topic.instantiate(attrs, types)
+
+    assert_equal 't.lo', topic.author_name
+  end
+
+  def test_typecasting_aliases
+    assert_equal 10, Topic.select('10 as tenderlove').first.tenderlove
+  end
+
+  def test_slice
+    company = Company.new(:rating => 1, :name => "37signals", :firm_name => "37signals")
+    hash = company.slice(:name, :rating, "arbitrary_method")
+    assert_equal hash[:name], company.name
+    assert_equal hash['name'], company.name
+    assert_equal hash[:rating], company.rating
+    assert_equal hash['arbitrary_method'], company.arbitrary_method
+    assert_equal hash[:arbitrary_method], company.arbitrary_method
+    assert_nil hash[:firm_name]
+    assert_nil hash['firm_name']
+  end
+
+  def test_default_values_are_deeply_dupped
+    company = Company.new
+    company.description << "foo"
+    assert_equal "", Company.new.description
+  end
+
+  ["find_by", "find_by!"].each do |meth|
+    test "#{meth} delegates to scoped" do
+      record = stub
+
+      scope = mock
+      scope.expects(meth).with(:foo, :bar).returns(record)
+
+      klass = Class.new(ActiveRecord::Base)
+      klass.stubs(:all => scope)
+
+      assert_equal record, klass.public_send(meth, :foo, :bar)
+    end
+  end
+
+  test "scoped can take a values hash" do
+    klass = Class.new(ActiveRecord::Base)
+    assert_equal ['foo'], klass.all.merge!(select: 'foo').select_values
+  end
+
+  test "connection_handler can be overridden" do
+    klass = Class.new(ActiveRecord::Base)
+    orig_handler = klass.connection_handler
+    new_handler = ActiveRecord::ConnectionAdapters::ConnectionHandler.new
+    thread_connection_handler = nil
+
+    t = Thread.new do
+      klass.connection_handler = new_handler
+      thread_connection_handler = klass.connection_handler
+    end
+    t.join
+
+    assert_equal klass.connection_handler, orig_handler
+    assert_equal thread_connection_handler, new_handler
+  end
+
+  test "new threads get default the default connection handler" do
+    klass = Class.new(ActiveRecord::Base)
+    orig_handler = klass.connection_handler
+    handler = nil
+
+    t = Thread.new do
+      handler = klass.connection_handler
+    end
+    t.join
+
+    assert_equal handler, orig_handler
+    assert_equal klass.connection_handler, orig_handler
+    assert_equal klass.default_connection_handler, orig_handler
+  end
+
+  test "changing a connection handler in a main thread does not poison the other threads" do
+    klass = Class.new(ActiveRecord::Base)
+    orig_handler = klass.connection_handler
+    new_handler = ActiveRecord::ConnectionAdapters::ConnectionHandler.new
+    after_handler = nil
+    latch1 = ActiveSupport::Concurrency::Latch.new
+    latch2 = ActiveSupport::Concurrency::Latch.new
+
+    t = Thread.new do
+      klass.connection_handler = new_handler
+      latch1.release
+      latch2.await
+      after_handler = klass.connection_handler
+    end
+
+    latch1.await
+
+    klass.connection_handler = orig_handler
+    latch2.release
+    t.join
+
+    assert_equal after_handler, new_handler
+    assert_equal orig_handler, klass.connection_handler
+  end
+
+  # Note: This is a performance optimization for Array#uniq and Hash#[] with
+  # AR::Base objects. If the future has made this irrelevant, feel free to
+  # delete this.
+  test "records without an id have unique hashes" do
+    assert_not_equal Post.new.hash, Post.new.hash
+  end
+end
diff --git a/activerecord/test/cases/batches_test.rb b/activerecord/test/cases/batches_test.rb
new file mode 100644
index 0000000000..c12fa03015
--- /dev/null
+++ b/activerecord/test/cases/batches_test.rb
@@ -0,0 +1,212 @@
+require 'cases/helper'
+require 'models/post'
+require 'models/subscriber'
+
+class EachTest < ActiveRecord::TestCase
+  fixtures :posts, :subscribers
+
+  def setup
+    @posts = Post.order("id asc")
+    @total = Post.count
+    Post.count('id') # preheat arel's table cache
+  end
+
+  def test_each_should_execute_one_query_per_batch
+    assert_queries(@total + 1) do
+      Post.find_each(:batch_size => 1) do |post|
+        assert_kind_of Post, post
+      end
+    end
+  end
+
+  def test_each_should_not_return_query_chain_and_execute_only_one_query
+    assert_queries(1) do
+      result = Post.find_each(:batch_size => 100000){ }
+      assert_nil result
+    end
+  end
+
+  def test_each_should_return_an_enumerator_if_no_block_is_present
+    assert_queries(1) do
+      Post.find_each(:batch_size => 100000).with_index do |post, index|
+        assert_kind_of Post, post
+        assert_kind_of Integer, index
+      end
+    end
+  end
+
+  if Enumerator.method_defined? :size
+    def test_each_should_return_a_sized_enumerator
+      assert_equal 11, Post.find_each(:batch_size => 1).size
+      assert_equal 5, Post.find_each(:batch_size => 2, :start => 7).size
+      assert_equal 11, Post.find_each(:batch_size => 10_000).size
+    end
+  end
+
+  def test_each_enumerator_should_execute_one_query_per_batch
+    assert_queries(@total + 1) do
+      Post.find_each(:batch_size => 1).with_index do |post, index|
+        assert_kind_of Post, post
+        assert_kind_of Integer, index
+      end
+    end
+  end
+
+  def test_each_should_raise_if_select_is_set_without_id
+    assert_raise(RuntimeError) do
+      Post.select(:title).find_each(batch_size: 1) { |post|
+        flunk "should not call this block"
+      }
+    end
+  end
+
+  def test_each_should_execute_if_id_is_in_select
+    assert_queries(6) do
+      Post.select("id, title, type").find_each(:batch_size => 2) do |post|
+        assert_kind_of Post, post
+      end
+    end
+  end
+
+  def test_warn_if_limit_scope_is_set
+    ActiveRecord::Base.logger.expects(:warn)
+    Post.limit(1).find_each { |post| post }
+  end
+
+  def test_warn_if_order_scope_is_set
+    ActiveRecord::Base.logger.expects(:warn)
+    Post.order("title").find_each { |post| post }
+  end
+
+  def test_logger_not_required
+    previous_logger = ActiveRecord::Base.logger
+    ActiveRecord::Base.logger = nil
+    assert_nothing_raised do
+      Post.limit(1).find_each { |post| post }
+    end
+  ensure
+    ActiveRecord::Base.logger = previous_logger
+  end
+
+  def test_find_in_batches_should_return_batches
+    assert_queries(@total + 1) do
+      Post.find_in_batches(:batch_size => 1) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  def test_find_in_batches_should_start_from_the_start_option
+    assert_queries(@total) do
+      Post.find_in_batches(:batch_size => 1, :start => 2) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  def test_find_in_batches_shouldnt_execute_query_unless_needed
+    assert_queries(2) do
+      Post.find_in_batches(:batch_size => @total) {|batch| assert_kind_of Array, batch }
+    end
+
+    assert_queries(1) do
+      Post.find_in_batches(:batch_size => @total + 1) {|batch| assert_kind_of Array, batch }
+    end
+  end
+
+  def test_find_in_batches_should_quote_batch_order
+    c = Post.connection
+    assert_sql(/ORDER BY #{c.quote_table_name('posts')}.#{c.quote_column_name('id')}/) do
+      Post.find_in_batches(:batch_size => 1) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  def test_find_in_batches_should_not_use_records_after_yielding_them_in_case_original_array_is_modified
+    not_a_post = "not a post"
+    not_a_post.stubs(:id).raises(StandardError, "not_a_post had #id called on it")
+
+    assert_nothing_raised do
+      Post.find_in_batches(:batch_size => 1) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+
+        batch.map! { not_a_post }
+      end
+    end
+  end
+
+  def test_find_in_batches_should_ignore_the_order_default_scope
+    # First post is with title scope
+    first_post = PostWithDefaultScope.first
+    posts = []
+    PostWithDefaultScope.find_in_batches  do |batch|
+      posts.concat(batch)
+    end
+    # posts.first will be ordered using id only. Title order scope should not apply here
+    assert_not_equal first_post, posts.first
+    assert_equal posts(:welcome), posts.first
+  end
+
+  def test_find_in_batches_should_not_ignore_the_default_scope_if_it_is_other_then_order
+    special_posts_ids = SpecialPostWithDefaultScope.all.map(&:id).sort
+    posts = []
+    SpecialPostWithDefaultScope.find_in_batches do |batch|
+      posts.concat(batch)
+    end
+    assert_equal special_posts_ids, posts.map(&:id)
+  end
+
+  def test_find_in_batches_should_not_modify_passed_options
+    assert_nothing_raised do
+      Post.find_in_batches({ batch_size: 42, start: 1 }.freeze){}
+    end
+  end
+
+  def test_find_in_batches_should_use_any_column_as_primary_key
+    nick_order_subscribers = Subscriber.order('nick asc')
+    start_nick = nick_order_subscribers.second.nick
+
+    subscribers = []
+    Subscriber.find_in_batches(:batch_size => 1, :start => start_nick) do |batch|
+      subscribers.concat(batch)
+    end
+
+    assert_equal nick_order_subscribers[1..-1].map(&:id), subscribers.map(&:id)
+  end
+
+  def test_find_in_batches_should_use_any_column_as_primary_key_when_start_is_not_specified
+    assert_queries(Subscriber.count + 1) do
+      Subscriber.find_each(:batch_size => 1) do |subscriber|
+        assert_kind_of Subscriber, subscriber
+      end
+    end
+  end
+
+  def test_find_in_batches_should_return_an_enumerator
+    enum = nil
+    assert_queries(0) do
+      enum = Post.find_in_batches(:batch_size => 1)
+    end
+    assert_queries(4) do
+      enum.first(4) do |batch|
+        assert_kind_of Array, batch
+        assert_kind_of Post, batch.first
+      end
+    end
+  end
+
+  if Enumerator.method_defined? :size
+    def test_find_in_batches_should_return_a_sized_enumerator
+      assert_equal 11, Post.find_in_batches(:batch_size => 1).size
+      assert_equal 6, Post.find_in_batches(:batch_size => 2).size
+      assert_equal 4, Post.find_in_batches(:batch_size => 2, :start => 4).size
+      assert_equal 4, Post.find_in_batches(:batch_size => 3).size
+      assert_equal 1, Post.find_in_batches(:batch_size => 10_000).size
+    end
+  end
+end
diff --git a/activerecord/test/cases/binary_test.rb b/activerecord/test/cases/binary_test.rb
new file mode 100644
index 0000000000..ccf2be369d
--- /dev/null
+++ b/activerecord/test/cases/binary_test.rb
@@ -0,0 +1,49 @@
+# encoding: utf-8
+require "cases/helper"
+
+# Without using prepared statements, it makes no sense to test
+# BLOB data with DB2, because the length of a statement
+# is limited to 32KB.
+unless current_adapter?(:DB2Adapter)
+  require 'models/binary'
+
+  class BinaryTest < ActiveRecord::TestCase
+    FIXTURES = %w(flowers.jpg example.log test.txt)
+
+    def test_mixed_encoding
+      str = "\x80"
+      str.force_encoding('ASCII-8BIT')
+
+      binary = Binary.new :name => 'いただきます！', :data => str
+      binary.save!
+      binary.reload
+      assert_equal str, binary.data
+
+      name = binary.name
+
+      # MySQL adapter doesn't properly encode things, so we have to do it
+      if current_adapter?(:MysqlAdapter)
+        name.force_encoding(Encoding::UTF_8)
+      end
+      assert_equal 'いただきます！', name
+    end
+
+    def test_load_save
+      Binary.delete_all
+
+      FIXTURES.each do |filename|
+        data = File.read(ASSETS_ROOT + "/#{filename}")
+        data.force_encoding('ASCII-8BIT')
+        data.freeze
+
+        bin = Binary.new(:data => data)
+        assert_equal data, bin.data, 'Newly assigned data differs from original'
+
+        bin.save!
+        assert_equal data, bin.data, 'Data differs from original after save'
+
+        assert_equal data, bin.reload.data, 'Reloaded data differs from original'
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/bind_parameter_test.rb b/activerecord/test/cases/bind_parameter_test.rb
new file mode 100644
index 0000000000..0bc7ee6d64
--- /dev/null
+++ b/activerecord/test/cases/bind_parameter_test.rb
@@ -0,0 +1,92 @@
+require 'cases/helper'
+require 'models/topic'
+
+module ActiveRecord
+  class BindParameterTest < ActiveRecord::TestCase
+    fixtures :topics
+
+    class LogListener
+      attr_accessor :calls
+
+      def initialize
+        @calls = []
+      end
+
+      def call(*args)
+        calls << args
+      end
+    end
+
+    def setup
+      super
+      @connection = ActiveRecord::Base.connection
+      @subscriber   = LogListener.new
+      @pk         = Topic.columns_hash[Topic.primary_key]
+      @subscription = ActiveSupport::Notifications.subscribe('sql.active_record', @subscriber)
+    end
+
+    teardown do
+      ActiveSupport::Notifications.unsubscribe(@subscription)
+    end
+
+    if ActiveRecord::Base.connection.supports_statement_cache?
+      def test_binds_are_logged
+        sub   = @connection.substitute_at(@pk, 0)
+        binds = [[@pk, 1]]
+        sql   = "select * from topics where id = #{sub}"
+
+        @connection.exec_query(sql, 'SQL', binds)
+
+        message = @subscriber.calls.find { |args| args[4][:sql] == sql }
+        assert_equal binds, message[4][:binds]
+      end
+
+      def test_binds_are_logged_after_type_cast
+        sub   = @connection.substitute_at(@pk, 0)
+        binds = [[@pk, "3"]]
+        sql   = "select * from topics where id = #{sub}"
+
+        @connection.exec_query(sql, 'SQL', binds)
+
+        message = @subscriber.calls.find { |args| args[4][:sql] == sql }
+        assert_equal [[@pk, 3]], message[4][:binds]
+      end
+
+      def test_find_one_uses_binds
+        Topic.find(1)
+        binds = [[@pk, 1]]
+        message = @subscriber.calls.find { |args| args[4][:binds] == binds }
+        assert message, 'expected a message with binds'
+      end
+
+      def test_logs_bind_vars
+        payload = {
+          :name  => 'SQL',
+          :sql   => 'select * from topics where id = ?',
+          :binds => [[@pk, 10]]
+        }
+        event  = ActiveSupport::Notifications::Event.new(
+          'foo',
+          Time.now,
+          Time.now,
+          123,
+          payload)
+
+        logger = Class.new(ActiveRecord::LogSubscriber) {
+          attr_reader :debugs
+          def initialize
+            super
+            @debugs = []
+          end
+
+          def debug str
+            @debugs << str
+          end
+        }.new
+
+        logger.sql event
+        assert_match([[@pk.name, 10]].inspect, logger.debugs.first)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
new file mode 100644
index 0000000000..319ea9260a
--- /dev/null
+++ b/activerecord/test/cases/calculations_test.rb
@@ -0,0 +1,615 @@
+require "cases/helper"
+require 'models/club'
+require 'models/company'
+require "models/contract"
+require 'models/edge'
+require 'models/organization'
+require 'models/possession'
+require 'models/topic'
+require 'models/reply'
+require 'models/minivan'
+require 'models/speedometer'
+require 'models/ship_part'
+
+Company.has_many :accounts
+
+class NumericData < ActiveRecord::Base
+  self.table_name = 'numeric_data'
+
+  attribute :world_population, Type::Integer.new
+  attribute :my_house_population, Type::Integer.new
+  attribute :atoms_in_universe, Type::Integer.new
+end
+
+class CalculationsTest < ActiveRecord::TestCase
+  fixtures :companies, :accounts, :topics
+
+  def test_should_sum_field
+    assert_equal 318, Account.sum(:credit_limit)
+  end
+
+  def test_should_average_field
+    value = Account.average(:credit_limit)
+    assert_equal 53.0, value
+  end
+
+  def test_should_resolve_aliased_attributes
+    assert_equal 318, Account.sum(:available_credit)
+  end
+
+  def test_should_return_decimal_average_of_integer_field
+    value = Account.average(:id)
+    assert_equal 3.5, value
+  end
+
+  def test_should_return_integer_average_if_db_returns_such
+    ShipPart.delete_all
+    ShipPart.create!(:id => 3, :name => 'foo')
+    value = ShipPart.average(:id)
+    assert_equal 3, value
+  end
+
+  def test_should_return_nil_as_average
+    assert_nil NumericData.average(:bank_balance)
+  end
+
+  def test_should_get_maximum_of_field
+    assert_equal 60, Account.maximum(:credit_limit)
+  end
+
+  def test_should_get_maximum_of_field_with_include
+    assert_equal 55, Account.where("companies.name != 'Summit'").references(:companies).includes(:firm).maximum(:credit_limit)
+  end
+
+  def test_should_get_minimum_of_field
+    assert_equal 50, Account.minimum(:credit_limit)
+  end
+
+  def test_should_group_by_field
+    c = Account.group(:firm_id).sum(:credit_limit)
+    [1,6,2].each do |firm_id|
+      assert c.keys.include?(firm_id), "Group #{c.inspect} does not contain firm_id #{firm_id}"
+    end
+  end
+
+  def test_should_group_by_arel_attribute
+    c = Account.group(Account.arel_table[:firm_id]).sum(:credit_limit)
+    [1,6,2].each do |firm_id|
+      assert c.keys.include?(firm_id), "Group #{c.inspect} does not contain firm_id #{firm_id}"
+    end
+  end
+
+  def test_should_group_by_multiple_fields
+    c = Account.group('firm_id', :credit_limit).count(:all)
+    [ [nil, 50], [1, 50], [6, 50], [6, 55], [9, 53], [2, 60] ].each { |firm_and_limit| assert c.keys.include?(firm_and_limit) }
+  end
+
+  def test_should_group_by_multiple_fields_having_functions
+    c = Topic.group(:author_name, 'COALESCE(type, title)').count(:all)
+    assert_equal 1, c[["Carl", "The Third Topic of the day"]]
+    assert_equal 1, c[["Mary", "Reply"]]
+    assert_equal 1, c[["David", "The First Topic"]]
+    assert_equal 1, c[["Carl", "Reply"]]
+  end
+
+  def test_should_group_by_summed_field
+    c = Account.group(:firm_id).sum(:credit_limit)
+    assert_equal 50,   c[1]
+    assert_equal 105,  c[6]
+    assert_equal 60,   c[2]
+  end
+
+  def test_should_order_by_grouped_field
+    c = Account.group(:firm_id).order("firm_id").sum(:credit_limit)
+    assert_equal [1, 2, 6, 9], c.keys.compact
+  end
+
+  def test_should_order_by_calculation
+    c = Account.group(:firm_id).order("sum_credit_limit desc, firm_id").sum(:credit_limit)
+    assert_equal [105, 60, 53, 50, 50], c.keys.collect { |k| c[k] }
+    assert_equal [6, 2, 9, 1], c.keys.compact
+  end
+
+  def test_should_limit_calculation
+    c = Account.where("firm_id IS NOT NULL").group(:firm_id).order("firm_id").limit(2).sum(:credit_limit)
+    assert_equal [1, 2], c.keys.compact
+  end
+
+  def test_should_limit_calculation_with_offset
+    c = Account.where("firm_id IS NOT NULL").group(:firm_id).order("firm_id").
+     limit(2).offset(1).sum(:credit_limit)
+    assert_equal [2, 6], c.keys.compact
+  end
+
+  def test_limit_should_apply_before_count
+    accounts = Account.limit(3).where('firm_id IS NOT NULL')
+
+    assert_equal 3, accounts.count(:firm_id)
+    assert_equal 3, accounts.select(:firm_id).count
+  end
+
+  def test_count_should_shortcut_with_limit_zero
+    accounts = Account.limit(0)
+
+    assert_no_queries { assert_equal 0, accounts.count }
+  end
+
+  def test_limit_is_kept
+    return if current_adapter?(:OracleAdapter)
+
+    queries = assert_sql { Account.limit(1).count }
+    assert_equal 1, queries.length
+    assert_match(/LIMIT/, queries.first)
+  end
+
+  def test_offset_is_kept
+    return if current_adapter?(:OracleAdapter)
+
+    queries = assert_sql { Account.offset(1).count }
+    assert_equal 1, queries.length
+    assert_match(/OFFSET/, queries.first)
+  end
+
+  def test_limit_with_offset_is_kept
+    return if current_adapter?(:OracleAdapter)
+
+    queries = assert_sql { Account.limit(1).offset(1).count }
+    assert_equal 1, queries.length
+    assert_match(/LIMIT/, queries.first)
+    assert_match(/OFFSET/, queries.first)
+  end
+
+  def test_no_limit_no_offset
+    queries = assert_sql { Account.count }
+    assert_equal 1, queries.length
+    assert_no_match(/LIMIT/, queries.first)
+    assert_no_match(/OFFSET/, queries.first)
+  end
+
+  def test_count_on_invalid_columns_raises
+    e = assert_raises(ActiveRecord::StatementInvalid) {
+      Account.select("credit_limit, firm_name").count
+    }
+
+    assert_match %r{accounts}i, e.message
+    assert_match "credit_limit, firm_name", e.message
+  end
+
+  def test_should_group_by_summed_field_having_condition
+    c = Account.group(:firm_id).having('sum(credit_limit) > 50').sum(:credit_limit)
+    assert_nil        c[1]
+    assert_equal 105, c[6]
+    assert_equal 60,  c[2]
+  end
+
+  def test_should_group_by_summed_field_having_condition_from_select
+    c = Account.select("MIN(credit_limit) AS min_credit_limit").group(:firm_id).having("MIN(credit_limit) > 50").sum(:credit_limit)
+    assert_nil       c[1]
+    assert_equal 60, c[2]
+    assert_equal 53, c[9]
+  end
+
+  def test_should_group_by_summed_association
+    c = Account.group(:firm).sum(:credit_limit)
+    assert_equal 50,   c[companies(:first_firm)]
+    assert_equal 105,  c[companies(:rails_core)]
+    assert_equal 60,   c[companies(:first_client)]
+  end
+
+  def test_should_sum_field_with_conditions
+    assert_equal 105, Account.where('firm_id = 6').sum(:credit_limit)
+  end
+
+  def test_should_return_zero_if_sum_conditions_return_nothing
+    assert_equal 0, Account.where('1 = 2').sum(:credit_limit)
+    assert_equal 0, companies(:rails_core).companies.where('1 = 2').sum(:id)
+  end
+
+  def test_sum_should_return_valid_values_for_decimals
+    NumericData.create(:bank_balance => 19.83)
+    assert_equal 19.83, NumericData.sum(:bank_balance)
+  end
+
+  def test_should_return_type_casted_values_with_group_and_expression
+    assert_equal 0.5, Account.group(:firm_name).sum('0.01 * credit_limit')['37signals']
+  end
+
+  def test_should_group_by_summed_field_with_conditions
+    c = Account.where('firm_id > 1').group(:firm_id).sum(:credit_limit)
+    assert_nil        c[1]
+    assert_equal 105, c[6]
+    assert_equal 60,  c[2]
+  end
+
+  def test_should_group_by_summed_field_with_conditions_and_having
+    c = Account.where('firm_id > 1').group(:firm_id).
+     having('sum(credit_limit) > 60').sum(:credit_limit)
+    assert_nil        c[1]
+    assert_equal 105, c[6]
+    assert_nil        c[2]
+  end
+
+  def test_should_group_by_fields_with_table_alias
+    c = Account.group('accounts.firm_id').sum(:credit_limit)
+    assert_equal 50,  c[1]
+    assert_equal 105, c[6]
+    assert_equal 60,  c[2]
+  end
+
+  def test_should_calculate_with_invalid_field
+    assert_equal 6, Account.calculate(:count, '*')
+    assert_equal 6, Account.calculate(:count, :all)
+  end
+
+  def test_should_calculate_grouped_with_invalid_field
+    c = Account.group('accounts.firm_id').count(:all)
+    assert_equal 1, c[1]
+    assert_equal 2, c[6]
+    assert_equal 1, c[2]
+  end
+
+  def test_should_calculate_grouped_association_with_invalid_field
+    c = Account.group(:firm).count(:all)
+    assert_equal 1, c[companies(:first_firm)]
+    assert_equal 2, c[companies(:rails_core)]
+    assert_equal 1, c[companies(:first_client)]
+  end
+
+  def test_should_group_by_association_with_non_numeric_foreign_key
+    Speedometer.create! id: 'ABC'
+    Minivan.create! id: 'OMG', speedometer_id: 'ABC'
+
+    c = Minivan.group(:speedometer).count(:all)
+    first_key = c.keys.first
+    assert_equal Speedometer, first_key.class
+    assert_equal 1, c[first_key]
+  end
+
+  def test_should_calculate_grouped_association_with_foreign_key_option
+    Account.belongs_to :another_firm, :class_name => 'Firm', :foreign_key => 'firm_id'
+    c = Account.group(:another_firm).count(:all)
+    assert_equal 1, c[companies(:first_firm)]
+    assert_equal 2, c[companies(:rails_core)]
+    assert_equal 1, c[companies(:first_client)]
+  end
+
+  def test_should_calculate_grouped_by_function
+    c = Company.group("UPPER(#{QUOTED_TYPE})").count(:all)
+    assert_equal 2, c[nil]
+    assert_equal 1, c['DEPENDENTFIRM']
+    assert_equal 5, c['CLIENT']
+    assert_equal 2, c['FIRM']
+  end
+
+  def test_should_calculate_grouped_by_function_with_table_alias
+    c = Company.group("UPPER(companies.#{QUOTED_TYPE})").count(:all)
+    assert_equal 2, c[nil]
+    assert_equal 1, c['DEPENDENTFIRM']
+    assert_equal 5, c['CLIENT']
+    assert_equal 2, c['FIRM']
+  end
+
+  def test_should_not_overshadow_enumerable_sum
+    assert_equal 6, [1, 2, 3].sum(&:abs)
+  end
+
+  def test_should_sum_scoped_field
+    assert_equal 15, companies(:rails_core).companies.sum(:id)
+  end
+
+  def test_should_sum_scoped_field_with_from
+    assert_equal Club.count, Organization.clubs.count
+  end
+
+  def test_should_sum_scoped_field_with_conditions
+    assert_equal 8,  companies(:rails_core).companies.where('id > 7').sum(:id)
+  end
+
+  def test_should_group_by_scoped_field
+    c = companies(:rails_core).companies.group(:name).sum(:id)
+    assert_equal 7, c['Leetsoft']
+    assert_equal 8, c['Jadedpixel']
+  end
+
+  def test_should_group_by_summed_field_through_association_and_having
+    c = companies(:rails_core).companies.group(:name).having('sum(id) > 7').sum(:id)
+    assert_nil      c['Leetsoft']
+    assert_equal 8, c['Jadedpixel']
+  end
+
+  def test_should_count_selected_field_with_include
+    assert_equal 6, Account.includes(:firm).distinct.count
+    assert_equal 4, Account.includes(:firm).distinct.select(:credit_limit).count
+  end
+
+  def test_should_not_perform_joined_include_by_default
+    assert_equal Account.count, Account.includes(:firm).count
+    queries = assert_sql { Account.includes(:firm).count }
+    assert_no_match(/join/i, queries.last)
+  end
+
+  def test_should_perform_joined_include_when_referencing_included_tables
+    joined_count = Account.includes(:firm).where(:companies => {:name => '37signals'}).count
+    assert_equal 1, joined_count
+  end
+
+  def test_should_count_scoped_select
+    Account.update_all("credit_limit = NULL")
+    assert_equal 0, Account.select("credit_limit").count
+  end
+
+  def test_should_count_scoped_select_with_options
+    Account.update_all("credit_limit = NULL")
+    Account.last.update_columns('credit_limit' => 49)
+    Account.first.update_columns('credit_limit' => 51)
+
+    assert_equal 1, Account.select("credit_limit").where('credit_limit >= 50').count
+  end
+
+  def test_should_count_manual_select_with_include
+    assert_equal 6, Account.select("DISTINCT accounts.id").includes(:firm).count
+  end
+
+  def test_count_with_column_parameter
+    assert_equal 5, Account.count(:firm_id)
+  end
+
+  def test_count_with_distinct
+    assert_equal 4, Account.select(:credit_limit).distinct.count
+    assert_equal 4, Account.select(:credit_limit).uniq.count
+  end
+
+  def test_count_with_aliased_attribute
+    assert_equal 6, Account.count(:available_credit)
+  end
+
+  def test_count_with_column_and_options_parameter
+    assert_equal 2, Account.where("credit_limit = 50 AND firm_id IS NOT NULL").count(:firm_id)
+  end
+
+  def test_should_count_field_in_joined_table
+    assert_equal 5, Account.joins(:firm).count('companies.id')
+    assert_equal 4, Account.joins(:firm).distinct.count('companies.id')
+  end
+
+  def test_should_count_field_in_joined_table_with_group_by
+    c = Account.group('accounts.firm_id').joins(:firm).count('companies.id')
+
+    [1,6,2,9].each { |firm_id| assert c.keys.include?(firm_id) }
+  end
+
+  def test_count_with_no_parameters_isnt_deprecated
+    assert_not_deprecated { Account.count }
+  end
+
+  def test_count_with_too_many_parameters_raises
+    assert_raise(ArgumentError) { Account.count(1, 2, 3) }
+  end
+
+  def test_count_with_order
+    assert_equal 6, Account.order(:credit_limit).count
+  end
+
+  def test_count_with_reverse_order
+    assert_equal 6, Account.order(:credit_limit).reverse_order.count
+  end
+
+  def test_count_with_where_and_order
+    assert_equal 1, Account.where(firm_name: '37signals').count
+    assert_equal 1, Account.where(firm_name: '37signals').order(:firm_name).count
+    assert_equal 1, Account.where(firm_name: '37signals').order(:firm_name).reverse_order.count
+  end
+
+  def test_should_sum_expression
+    # Oracle adapter returns floating point value 636.0 after SUM
+    if current_adapter?(:OracleAdapter)
+      assert_equal 636, Account.sum("2 * credit_limit")
+    else
+      assert_equal 636, Account.sum("2 * credit_limit").to_i
+    end
+  end
+
+  def test_sum_expression_returns_zero_when_no_records_to_sum
+    assert_equal 0, Account.where('1 = 2').sum("2 * credit_limit")
+  end
+
+  def test_count_with_from_option
+    assert_equal Company.count(:all), Company.from('companies').count(:all)
+    assert_equal Account.where("credit_limit = 50").count(:all),
+        Account.from('accounts').where("credit_limit = 50").count(:all)
+    assert_equal Company.where(:type => "Firm").count(:type),
+        Company.where(:type => "Firm").from('companies').count(:type)
+  end
+
+  def test_sum_with_from_option
+    assert_equal Account.sum(:credit_limit), Account.from('accounts').sum(:credit_limit)
+    assert_equal Account.where("credit_limit > 50").sum(:credit_limit),
+        Account.where("credit_limit > 50").from('accounts').sum(:credit_limit)
+  end
+
+  def test_average_with_from_option
+    assert_equal Account.average(:credit_limit), Account.from('accounts').average(:credit_limit)
+    assert_equal Account.where("credit_limit > 50").average(:credit_limit),
+        Account.where("credit_limit > 50").from('accounts').average(:credit_limit)
+  end
+
+  def test_minimum_with_from_option
+    assert_equal Account.minimum(:credit_limit), Account.from('accounts').minimum(:credit_limit)
+    assert_equal Account.where("credit_limit > 50").minimum(:credit_limit),
+        Account.where("credit_limit > 50").from('accounts').minimum(:credit_limit)
+  end
+
+  def test_maximum_with_from_option
+    assert_equal Account.maximum(:credit_limit), Account.from('accounts').maximum(:credit_limit)
+    assert_equal Account.where("credit_limit > 50").maximum(:credit_limit),
+        Account.where("credit_limit > 50").from('accounts').maximum(:credit_limit)
+  end
+
+  def test_maximum_with_not_auto_table_name_prefix_if_column_included
+    Company.create!(:name => "test", :contracts => [Contract.new(:developer_id => 7)])
+
+    assert_equal 7, Company.includes(:contracts).maximum(:developer_id)
+  end
+
+  def test_minimum_with_not_auto_table_name_prefix_if_column_included
+    Company.create!(:name => "test", :contracts => [Contract.new(:developer_id => 7)])
+
+    assert_equal 7, Company.includes(:contracts).minimum(:developer_id)
+  end
+
+  def test_sum_with_not_auto_table_name_prefix_if_column_included
+    Company.create!(:name => "test", :contracts => [Contract.new(:developer_id => 7)])
+
+    assert_equal 7, Company.includes(:contracts).sum(:developer_id)
+  end
+
+
+  def test_from_option_with_specified_index
+    if Edge.connection.adapter_name == 'MySQL' or Edge.connection.adapter_name == 'Mysql2'
+      assert_equal Edge.count(:all), Edge.from('edges USE INDEX(unique_edge_index)').count(:all)
+      assert_equal Edge.where('sink_id < 5').count(:all),
+          Edge.from('edges USE INDEX(unique_edge_index)').where('sink_id < 5').count(:all)
+    end
+  end
+
+  def test_from_option_with_table_different_than_class
+    assert_equal Account.count(:all), Company.from('accounts').count(:all)
+  end
+
+  def test_distinct_is_honored_when_used_with_count_operation_after_group
+    # Count the number of authors for approved topics
+    approved_topics_count = Topic.group(:approved).count(:author_name)[true]
+    assert_equal approved_topics_count, 4
+    # Count the number of distinct authors for approved Topics
+    distinct_authors_for_approved_count = Topic.group(:approved).distinct.count(:author_name)[true]
+    assert_equal distinct_authors_for_approved_count, 3
+  end
+
+  def test_pluck
+    assert_equal [1,2,3,4,5], Topic.order(:id).pluck(:id)
+  end
+
+  def test_pluck_without_column_names
+    assert_equal [[1, "Firm", 1, nil, "37signals", nil, 1, nil, ""]],
+      Company.order(:id).limit(1).pluck
+  end
+
+  def test_pluck_type_cast
+    topic = topics(:first)
+    relation = Topic.where(:id => topic.id)
+    assert_equal [ topic.approved ], relation.pluck(:approved)
+    assert_equal [ topic.last_read ], relation.pluck(:last_read)
+    assert_equal [ topic.written_on ], relation.pluck(:written_on)
+  end
+
+  def test_pluck_and_uniq
+    assert_equal [50, 53, 55, 60], Account.order(:credit_limit).uniq.pluck(:credit_limit)
+  end
+
+  def test_pluck_in_relation
+    company = Company.first
+    contract = company.contracts.create!
+    assert_equal [contract.id], company.contracts.pluck(:id)
+  end
+
+  def test_pluck_on_aliased_attribute
+    assert_equal 'The First Topic', Topic.order(:id).pluck(:heading).first
+  end
+
+  def test_pluck_with_serialization
+    t = Topic.create!(:content => { :foo => :bar })
+    assert_equal [{:foo => :bar}], Topic.where(:id => t.id).pluck(:content)
+  end
+
+  def test_pluck_with_qualified_column_name
+    assert_equal [1,2,3,4,5], Topic.order(:id).pluck("topics.id")
+  end
+
+  def test_pluck_auto_table_name_prefix
+    c = Company.create!(:name => "test", :contracts => [Contract.new])
+    assert_equal [c.id], Company.joins(:contracts).pluck(:id)
+  end
+
+  def test_pluck_if_table_included
+    c = Company.create!(:name => "test", :contracts => [Contract.new(:developer_id => 7)])
+    assert_equal [c.id], Company.includes(:contracts).where("contracts.id" => c.contracts.first).pluck(:id)
+  end
+
+  def test_pluck_not_auto_table_name_prefix_if_column_joined
+    Company.create!(:name => "test", :contracts => [Contract.new(:developer_id => 7)])
+    assert_equal [7], Company.joins(:contracts).pluck(:developer_id)
+  end
+
+  def test_pluck_with_selection_clause
+    assert_equal [50, 53, 55, 60], Account.pluck('DISTINCT credit_limit').sort
+    assert_equal [50, 53, 55, 60], Account.pluck('DISTINCT accounts.credit_limit').sort
+    assert_equal [50, 53, 55, 60], Account.pluck('DISTINCT(credit_limit)').sort
+
+    # MySQL returns "SUM(DISTINCT(credit_limit))" as the column name unless
+    # an alias is provided.  Without the alias, the column cannot be found
+    # and properly typecast.
+    assert_equal [50 + 53 + 55 + 60], Account.pluck('SUM(DISTINCT(credit_limit)) as credit_limit')
+  end
+
+  def test_plucks_with_ids
+    assert_equal Company.all.map(&:id).sort, Company.ids.sort
+  end
+
+  def test_pluck_with_includes_limit_and_empty_result
+    assert_equal [], Topic.includes(:replies).limit(0).pluck(:id)
+    assert_equal [], Topic.includes(:replies).limit(1).where('0 = 1').pluck(:id)
+  end
+
+  def test_pluck_not_auto_table_name_prefix_if_column_included
+    Company.create!(:name => "test", :contracts => [Contract.new(:developer_id => 7)])
+    ids = Company.includes(:contracts).pluck(:developer_id)
+    assert_equal Company.count, ids.length
+    assert_equal [7], ids.compact
+  end
+
+  def test_pluck_multiple_columns
+    assert_equal [
+      [1, "The First Topic"], [2, "The Second Topic of the day"],
+      [3, "The Third Topic of the day"], [4, "The Fourth Topic of the day"],
+      [5, "The Fifth Topic of the day"]
+    ], Topic.order(:id).pluck(:id, :title)
+    assert_equal [
+      [1, "The First Topic", "David"], [2, "The Second Topic of the day", "Mary"],
+      [3, "The Third Topic of the day", "Carl"], [4, "The Fourth Topic of the day", "Carl"],
+      [5, "The Fifth Topic of the day", "Jason"]
+    ], Topic.order(:id).pluck(:id, :title, :author_name)
+  end
+
+  def test_pluck_with_multiple_columns_and_selection_clause
+    assert_equal [[1, 50], [2, 50], [3, 50], [4, 60], [5, 55], [6, 53]],
+      Account.pluck('id, credit_limit')
+  end
+
+  def test_pluck_with_multiple_columns_and_includes
+    Company.create!(:name => "test", :contracts => [Contract.new(:developer_id => 7)])
+    companies_and_developers = Company.order('companies.id').includes(:contracts).pluck(:name, :developer_id)
+
+    assert_equal Company.count, companies_and_developers.length
+    assert_equal ["37signals", nil], companies_and_developers.first
+    assert_equal ["test", 7], companies_and_developers.last
+  end
+
+  def test_pluck_with_reserved_words
+    Possession.create!(:where => "Over There")
+
+    assert_equal ["Over There"], Possession.pluck(:where)
+  end
+
+  def test_pluck_replaces_select_clause
+    taks_relation = Topic.select(:approved, :id).order(:id)
+    assert_equal [1,2,3,4,5], taks_relation.pluck(:id)
+    assert_equal [false, true, true, true, true], taks_relation.pluck(:approved)
+  end
+
+  def test_pluck_columns_with_same_name
+    expected = [["The First Topic", "The Second Topic of the day"], ["The Third Topic of the day", "The Fourth Topic of the day"]]
+    actual = Topic.joins(:replies)
+      .pluck('topics.title', 'replies_topics.title')
+    assert_equal expected, actual
+  end
+end
diff --git a/activerecord/test/cases/callbacks_test.rb b/activerecord/test/cases/callbacks_test.rb
new file mode 100644
index 0000000000..c8f56e3c73
--- /dev/null
+++ b/activerecord/test/cases/callbacks_test.rb
@@ -0,0 +1,535 @@
+require "cases/helper"
+
+class CallbackDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  class << self
+    def callback_string(callback_method)
+      "history << [#{callback_method.to_sym.inspect}, :string]"
+    end
+
+    def callback_proc(callback_method)
+      Proc.new { |model| model.history << [callback_method, :proc] }
+    end
+
+    def define_callback_method(callback_method)
+      define_method(callback_method) do
+        self.history << [callback_method, :method]
+      end
+      send(callback_method, :"#{callback_method}")
+    end
+
+    def callback_object(callback_method)
+      klass = Class.new
+      klass.send(:define_method, callback_method) do |model|
+        model.history << [callback_method, :object]
+      end
+      klass.new
+    end
+  end
+
+  ActiveRecord::Callbacks::CALLBACKS.each do |callback_method|
+    next if callback_method.to_s =~ /^around_/
+    define_callback_method(callback_method)
+    send(callback_method, callback_string(callback_method))
+    send(callback_method, callback_proc(callback_method))
+    send(callback_method, callback_object(callback_method))
+    send(callback_method) { |model| model.history << [callback_method, :block] }
+  end
+
+  def history
+    @history ||= []
+  end
+end
+
+class CallbackDeveloperWithFalseValidation < CallbackDeveloper
+  before_validation proc { |model| model.history << [:before_validation, :returning_false]; false }
+  before_validation proc { |model| model.history << [:before_validation, :should_never_get_here] }
+end
+
+class ParentDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+  attr_accessor :after_save_called
+  before_validation {|record| record.after_save_called = true}
+end
+
+class ChildDeveloper < ParentDeveloper
+
+end
+
+class RecursiveCallbackDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  before_save :on_before_save
+  after_save :on_after_save
+
+  attr_reader :on_before_save_called, :on_after_save_called
+
+  def on_before_save
+    @on_before_save_called ||= 0
+    @on_before_save_called += 1
+    save unless @on_before_save_called > 1
+  end
+
+  def on_after_save
+    @on_after_save_called ||= 0
+    @on_after_save_called += 1
+    save unless @on_after_save_called > 1
+  end
+end
+
+class ImmutableDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  validates_inclusion_of :salary, :in => 50000..200000
+
+  before_save :cancel
+  before_destroy :cancel
+
+  def cancelled?
+    @cancelled == true
+  end
+
+  private
+    def cancel
+      @cancelled = true
+      false
+    end
+end
+
+class ImmutableMethodDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  validates_inclusion_of :salary, :in => 50000..200000
+
+  def cancelled?
+    @cancelled == true
+  end
+
+  before_save do
+    @cancelled = true
+    false
+  end
+
+  before_destroy do
+    @cancelled = true
+    false
+  end
+end
+
+class OnCallbacksDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  before_validation { history << :before_validation }
+  before_validation(:on => :create){ history << :before_validation_on_create }
+  before_validation(:on => :update){ history << :before_validation_on_update }
+
+  validate do
+    history << :validate
+  end
+
+  after_validation { history << :after_validation }
+  after_validation(:on => :create){ history << :after_validation_on_create }
+  after_validation(:on => :update){ history << :after_validation_on_update }
+
+  def history
+    @history ||= []
+  end
+end
+
+class ContextualCallbacksDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  before_validation { history << :before_validation }
+  before_validation :before_validation_on_create_and_update, :on => [ :create, :update ]
+
+  validate do
+    history << :validate
+  end
+
+  after_validation { history << :after_validation }
+  after_validation :after_validation_on_create_and_update, :on => [ :create, :update ]
+
+  def before_validation_on_create_and_update
+    history << "before_validation_on_#{self.validation_context}".to_sym
+  end
+
+  def after_validation_on_create_and_update
+    history << "after_validation_on_#{self.validation_context}".to_sym
+  end
+
+  def history
+    @history ||= []
+  end
+end
+
+class CallbackCancellationDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  attr_reader   :after_save_called, :after_create_called, :after_update_called, :after_destroy_called
+  attr_accessor :cancel_before_save, :cancel_before_create, :cancel_before_update, :cancel_before_destroy
+
+  before_save    {defined?(@cancel_before_save) ? !@cancel_before_save : false}
+  before_create  { !@cancel_before_create  }
+  before_update  { !@cancel_before_update  }
+  before_destroy { !@cancel_before_destroy }
+
+  after_save    { @after_save_called    = true }
+  after_update  { @after_update_called  = true }
+  after_create  { @after_create_called  = true }
+  after_destroy { @after_destroy_called = true }
+end
+
+class CallbacksTest < ActiveRecord::TestCase
+  fixtures :developers
+
+  def test_initialize
+    david = CallbackDeveloper.new
+    assert_equal [
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+    ], david.history
+  end
+
+  def test_find
+    david = CallbackDeveloper.find(1)
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :string ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+    ], david.history
+  end
+
+  def test_new_valid?
+    david = CallbackDeveloper.new
+    david.valid?
+    assert_equal [
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :string ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :after_validation,            :method ],
+      [ :after_validation,            :string ],
+      [ :after_validation,            :proc   ],
+      [ :after_validation,            :object ],
+      [ :after_validation,            :block  ],
+    ], david.history
+  end
+
+  def test_existing_valid?
+    david = CallbackDeveloper.find(1)
+    david.valid?
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :string ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :string ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :after_validation,            :method ],
+      [ :after_validation,            :string ],
+      [ :after_validation,            :proc   ],
+      [ :after_validation,            :object ],
+      [ :after_validation,            :block  ],
+    ], david.history
+  end
+
+  def test_create
+    david = CallbackDeveloper.create('name' => 'David', 'salary' => 1000000)
+    assert_equal [
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :string ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :after_validation,            :method ],
+      [ :after_validation,            :string ],
+      [ :after_validation,            :proc   ],
+      [ :after_validation,            :object ],
+      [ :after_validation,            :block  ],
+      [ :before_save,                 :method ],
+      [ :before_save,                 :string ],
+      [ :before_save,                 :proc   ],
+      [ :before_save,                 :object ],
+      [ :before_save,                 :block  ],
+      [ :before_create,               :method ],
+      [ :before_create,               :string ],
+      [ :before_create,               :proc   ],
+      [ :before_create,               :object ],
+      [ :before_create,               :block  ],
+      [ :after_create,                :method ],
+      [ :after_create,                :string ],
+      [ :after_create,                :proc   ],
+      [ :after_create,                :object ],
+      [ :after_create,                :block  ],
+      [ :after_save,                  :method ],
+      [ :after_save,                  :string ],
+      [ :after_save,                  :proc   ],
+      [ :after_save,                  :object ],
+      [ :after_save,                  :block  ]
+    ], david.history
+  end
+
+  def test_validate_on_create
+    david = OnCallbacksDeveloper.create('name' => 'David', 'salary' => 1000000)
+    assert_equal [
+      :before_validation,
+      :before_validation_on_create,
+      :validate,
+      :after_validation,
+      :after_validation_on_create
+    ], david.history
+  end
+
+  def test_validate_on_contextual_create
+    david = ContextualCallbacksDeveloper.create('name' => 'David', 'salary' => 1000000)
+    assert_equal [
+      :before_validation,
+      :before_validation_on_create,
+      :validate,
+      :after_validation,
+      :after_validation_on_create
+    ], david.history
+  end
+
+  def test_update
+    david = CallbackDeveloper.find(1)
+    david.save
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :string ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :string ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :after_validation,            :method ],
+      [ :after_validation,            :string ],
+      [ :after_validation,            :proc   ],
+      [ :after_validation,            :object ],
+      [ :after_validation,            :block  ],
+      [ :before_save,                 :method ],
+      [ :before_save,                 :string ],
+      [ :before_save,                 :proc   ],
+      [ :before_save,                 :object ],
+      [ :before_save,                 :block  ],
+      [ :before_update,               :method ],
+      [ :before_update,               :string ],
+      [ :before_update,               :proc   ],
+      [ :before_update,               :object ],
+      [ :before_update,               :block  ],
+      [ :after_update,                :method ],
+      [ :after_update,                :string ],
+      [ :after_update,                :proc   ],
+      [ :after_update,                :object ],
+      [ :after_update,                :block  ],
+      [ :after_save,                  :method ],
+      [ :after_save,                  :string ],
+      [ :after_save,                  :proc   ],
+      [ :after_save,                  :object ],
+      [ :after_save,                  :block  ]
+    ], david.history
+  end
+
+  def test_validate_on_update
+    david = OnCallbacksDeveloper.find(1)
+    david.save
+    assert_equal [
+      :before_validation,
+      :before_validation_on_update,
+      :validate,
+      :after_validation,
+      :after_validation_on_update
+    ], david.history
+  end
+
+  def test_validate_on_contextual_update
+    david = ContextualCallbacksDeveloper.find(1)
+    david.save
+    assert_equal [
+      :before_validation,
+      :before_validation_on_update,
+      :validate,
+      :after_validation,
+      :after_validation_on_update
+    ], david.history
+  end
+
+  def test_destroy
+    david = CallbackDeveloper.find(1)
+    david.destroy
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :string ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_destroy,              :method ],
+      [ :before_destroy,              :string ],
+      [ :before_destroy,              :proc   ],
+      [ :before_destroy,              :object ],
+      [ :before_destroy,              :block  ],
+      [ :after_destroy,               :method ],
+      [ :after_destroy,               :string ],
+      [ :after_destroy,               :proc   ],
+      [ :after_destroy,               :object ],
+      [ :after_destroy,               :block  ]
+    ], david.history
+  end
+
+  def test_delete
+    david = CallbackDeveloper.find(1)
+    CallbackDeveloper.delete(david.id)
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :string ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+    ], david.history
+  end
+
+  def test_before_save_returning_false
+    david = ImmutableDeveloper.find(1)
+    assert david.valid?
+    assert !david.save
+    assert_raise(ActiveRecord::RecordNotSaved) { david.save! }
+
+    david = ImmutableDeveloper.find(1)
+    david.salary = 10_000_000
+    assert !david.valid?
+    assert !david.save
+    assert_raise(ActiveRecord::RecordInvalid) { david.save! }
+
+    someone = CallbackCancellationDeveloper.find(1)
+    someone.cancel_before_save = true
+    assert someone.valid?
+    assert !someone.save
+    assert_save_callbacks_not_called(someone)
+  end
+
+  def test_before_create_returning_false
+    someone = CallbackCancellationDeveloper.new
+    someone.cancel_before_create = true
+    assert someone.valid?
+    assert !someone.save
+    assert_save_callbacks_not_called(someone)
+  end
+
+  def test_before_update_returning_false
+    someone = CallbackCancellationDeveloper.find(1)
+    someone.cancel_before_update = true
+    assert someone.valid?
+    assert !someone.save
+    assert_save_callbacks_not_called(someone)
+  end
+
+  def test_before_destroy_returning_false
+    david = ImmutableDeveloper.find(1)
+    assert !david.destroy
+    assert_raise(ActiveRecord::RecordNotDestroyed) { david.destroy! }
+    assert_not_nil ImmutableDeveloper.find_by_id(1)
+
+    someone = CallbackCancellationDeveloper.find(1)
+    someone.cancel_before_destroy = true
+    assert !someone.destroy
+    assert_raise(ActiveRecord::RecordNotDestroyed) { someone.destroy! }
+    assert !someone.after_destroy_called
+  end
+
+  def assert_save_callbacks_not_called(someone)
+    assert !someone.after_save_called
+    assert !someone.after_create_called
+    assert !someone.after_update_called
+  end
+  private :assert_save_callbacks_not_called
+
+  def test_callback_returning_false
+    david = CallbackDeveloperWithFalseValidation.find(1)
+    david.save
+    assert_equal [
+      [ :after_find,            :method ],
+      [ :after_find,            :string ],
+      [ :after_find,            :proc   ],
+      [ :after_find,            :object ],
+      [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
+      [ :after_initialize,            :string ],
+      [ :after_initialize,            :proc   ],
+      [ :after_initialize,            :object ],
+      [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
+      [ :before_validation,           :string ],
+      [ :before_validation,           :proc   ],
+      [ :before_validation,           :object ],
+      [ :before_validation,           :block  ],
+      [ :before_validation, :returning_false  ],
+      [ :after_rollback, :block  ],
+      [ :after_rollback, :object ],
+      [ :after_rollback, :proc   ],
+      [ :after_rollback, :string ],
+      [ :after_rollback, :method ],
+    ], david.history
+  end
+
+  def test_inheritance_of_callbacks
+    parent = ParentDeveloper.new
+    assert !parent.after_save_called
+    parent.save
+    assert parent.after_save_called
+
+    child = ChildDeveloper.new
+    assert !child.after_save_called
+    child.save
+    assert child.after_save_called
+  end
+
+end
diff --git a/activerecord/test/cases/clone_test.rb b/activerecord/test/cases/clone_test.rb
new file mode 100644
index 0000000000..5e43082c33
--- /dev/null
+++ b/activerecord/test/cases/clone_test.rb
@@ -0,0 +1,40 @@
+require "cases/helper"
+require 'models/topic'
+
+module ActiveRecord
+  class CloneTest < ActiveRecord::TestCase
+    fixtures :topics
+
+    def test_persisted
+      topic = Topic.first
+      cloned = topic.clone
+      assert topic.persisted?, 'topic persisted'
+      assert cloned.persisted?, 'topic persisted'
+      assert !cloned.new_record?, 'topic is not new'
+    end
+
+    def test_stays_frozen
+      topic = Topic.first
+      topic.freeze
+
+      cloned = topic.clone
+      assert cloned.persisted?, 'topic persisted'
+      assert !cloned.new_record?, 'topic is not new'
+      assert cloned.frozen?, 'topic should be frozen'
+    end
+
+    def test_shallow
+      topic = Topic.first
+      cloned = topic.clone
+      topic.author_name = 'Aaron'
+      assert_equal 'Aaron', cloned.author_name
+    end
+
+    def test_freezing_a_cloned_model_does_not_freeze_clone
+      cloned = Topic.new
+      clone = cloned.clone
+      cloned.freeze
+      assert_not clone.frozen?
+    end
+  end
+end
diff --git a/activerecord/test/cases/coders/yaml_column_test.rb b/activerecord/test/cases/coders/yaml_column_test.rb
new file mode 100644
index 0000000000..b72c54f97b
--- /dev/null
+++ b/activerecord/test/cases/coders/yaml_column_test.rb
@@ -0,0 +1,63 @@
+
+require "cases/helper"
+
+module ActiveRecord
+  module Coders
+    class YAMLColumnTest < ActiveRecord::TestCase
+      def test_initialize_takes_class
+        coder = YAMLColumn.new(Object)
+        assert_equal Object, coder.object_class
+      end
+
+      def test_type_mismatch_on_different_classes_on_dump
+        coder = YAMLColumn.new(Array)
+        assert_raises(SerializationTypeMismatch) do
+          coder.dump("a")
+        end
+      end
+
+      def test_type_mismatch_on_different_classes
+        coder = YAMLColumn.new(Array)
+        assert_raises(SerializationTypeMismatch) do
+          coder.load "--- foo"
+        end
+      end
+
+      def test_nil_is_ok
+        coder = YAMLColumn.new
+        assert_nil coder.load "--- "
+      end
+
+      def test_returns_new_with_different_class
+        coder = YAMLColumn.new SerializationTypeMismatch
+        assert_equal SerializationTypeMismatch, coder.load("--- ").class
+      end
+
+      def test_returns_string_unless_starts_with_dash
+        coder = YAMLColumn.new
+        assert_equal 'foo', coder.load("foo")
+      end
+
+      def test_load_handles_other_classes
+        coder = YAMLColumn.new
+        assert_equal [], coder.load([])
+      end
+
+      def test_load_doesnt_swallow_yaml_exceptions
+        coder = YAMLColumn.new
+        bad_yaml = '--- {'
+        assert_raises(Psych::SyntaxError) do
+          coder.load(bad_yaml)
+        end
+      end
+
+      def test_load_doesnt_handle_undefined_class_or_module
+        coder = YAMLColumn.new
+        missing_class_yaml = '--- !ruby/object:DoesNotExistAndShouldntEver {}\n'
+        assert_raises(ArgumentError) do
+          coder.load(missing_class_yaml)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/column_alias_test.rb b/activerecord/test/cases/column_alias_test.rb
new file mode 100644
index 0000000000..40707d9cb2
--- /dev/null
+++ b/activerecord/test/cases/column_alias_test.rb
@@ -0,0 +1,17 @@
+require "cases/helper"
+require 'models/topic'
+
+class TestColumnAlias < ActiveRecord::TestCase
+  fixtures :topics
+
+  QUERY = if 'Oracle' == ActiveRecord::Base.connection.adapter_name
+            'SELECT id AS pk FROM topics WHERE ROWNUM < 2'
+          else
+            'SELECT id AS pk FROM topics'
+          end
+
+  def test_column_alias
+    records = Topic.connection.select_all(QUERY)
+    assert_equal 'pk', records[0].keys[0]
+  end
+end
diff --git a/activerecord/test/cases/column_definition_test.rb b/activerecord/test/cases/column_definition_test.rb
new file mode 100644
index 0000000000..bcfd66b4bf
--- /dev/null
+++ b/activerecord/test/cases/column_definition_test.rb
@@ -0,0 +1,123 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ColumnDefinitionTest < ActiveRecord::TestCase
+      def setup
+        @adapter = AbstractAdapter.new(nil)
+        def @adapter.native_database_types
+          {:string => "varchar"}
+        end
+        @viz = @adapter.schema_creation
+      end
+
+      # Avoid column definitions in create table statements like:
+      # `title` varchar(255) DEFAULT NULL
+      def test_should_not_include_default_clause_when_default_is_null
+        column = Column.new("title", nil, Type::String.new(limit: 20))
+        column_def = ColumnDefinition.new(
+          column.name, "string",
+          column.limit, column.precision, column.scale, column.default, column.null)
+          assert_equal "title varchar(20)", @viz.accept(column_def)
+      end
+
+      def test_should_include_default_clause_when_default_is_present
+        column = Column.new("title", "Hello", Type::String.new(limit: 20))
+        column_def = ColumnDefinition.new(
+          column.name, "string",
+          column.limit, column.precision, column.scale, column.default, column.null)
+          assert_equal %Q{title varchar(20) DEFAULT 'Hello'}, @viz.accept(column_def)
+      end
+
+      def test_should_specify_not_null_if_null_option_is_false
+        column = Column.new("title", "Hello", Type::String.new(limit: 20), "varchar(20)", false)
+        column_def = ColumnDefinition.new(
+          column.name, "string",
+          column.limit, column.precision, column.scale, column.default, column.null)
+          assert_equal %Q{title varchar(20) DEFAULT 'Hello' NOT NULL}, @viz.accept(column_def)
+      end
+
+      if current_adapter?(:MysqlAdapter)
+        def test_should_set_default_for_mysql_binary_data_types
+          binary_column = MysqlAdapter::Column.new("title", "a", Type::Binary.new, "binary(1)")
+          assert_equal "a", binary_column.default
+
+          varbinary_column = MysqlAdapter::Column.new("title", "a", Type::Binary.new, "varbinary(1)")
+          assert_equal "a", varbinary_column.default
+        end
+
+        def test_should_not_set_default_for_blob_and_text_data_types
+          assert_raise ArgumentError do
+            MysqlAdapter::Column.new("title", "a", Type::Binary.new, "blob")
+          end
+
+          assert_raise ArgumentError do
+            MysqlAdapter::Column.new("title", "Hello", Type::Text.new)
+          end
+
+          text_column = MysqlAdapter::Column.new("title", nil, Type::Text.new)
+          assert_equal nil, text_column.default
+
+          not_null_text_column = MysqlAdapter::Column.new("title", nil, Type::Text.new, "text", false)
+          assert_equal "", not_null_text_column.default
+        end
+
+        def test_has_default_should_return_false_for_blob_and_text_data_types
+          blob_column = MysqlAdapter::Column.new("title", nil, Type::Binary.new, "blob")
+          assert !blob_column.has_default?
+
+          text_column = MysqlAdapter::Column.new("title", nil, Type::Text.new)
+          assert !text_column.has_default?
+        end
+      end
+
+      if current_adapter?(:Mysql2Adapter)
+        def test_should_set_default_for_mysql_binary_data_types
+          binary_column = Mysql2Adapter::Column.new("title", "a", Type::Binary.new, "binary(1)")
+          assert_equal "a", binary_column.default
+
+          varbinary_column = Mysql2Adapter::Column.new("title", "a", Type::Binary.new, "varbinary(1)")
+          assert_equal "a", varbinary_column.default
+        end
+
+        def test_should_not_set_default_for_blob_and_text_data_types
+          assert_raise ArgumentError do
+            Mysql2Adapter::Column.new("title", "a", Type::Binary.new, "blob")
+          end
+
+          assert_raise ArgumentError do
+            Mysql2Adapter::Column.new("title", "Hello", Type::Text.new)
+          end
+
+          text_column = Mysql2Adapter::Column.new("title", nil, Type::Text.new)
+          assert_equal nil, text_column.default
+
+          not_null_text_column = Mysql2Adapter::Column.new("title", nil, Type::Text.new, "text", false)
+          assert_equal "", not_null_text_column.default
+        end
+
+        def test_has_default_should_return_false_for_blob_and_text_data_types
+          blob_column = Mysql2Adapter::Column.new("title", nil, Type::Binary.new, "blob")
+          assert !blob_column.has_default?
+
+          text_column = Mysql2Adapter::Column.new("title", nil, Type::Text.new)
+          assert !text_column.has_default?
+        end
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_bigint_column_should_map_to_integer
+          oid = PostgreSQLAdapter::OID::Integer.new
+          bigint_column = PostgreSQLColumn.new('number', nil, oid, "bigint")
+          assert_equal :integer, bigint_column.type
+        end
+
+        def test_smallint_column_should_map_to_integer
+          oid = PostgreSQLAdapter::OID::Integer.new
+          smallint_column = PostgreSQLColumn.new('number', nil, oid, "smallint")
+          assert_equal :integer, smallint_column.type
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/adapter_leasing_test.rb b/activerecord/test/cases/connection_adapters/adapter_leasing_test.rb
new file mode 100644
index 0000000000..662e19f35e
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/adapter_leasing_test.rb
@@ -0,0 +1,54 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class AdapterLeasingTest < ActiveRecord::TestCase
+      class Pool < ConnectionPool
+        def insert_connection_for_test!(c)
+          synchronize do
+            @connections << c
+            @available.add c
+          end
+        end
+      end
+
+      def setup
+        @adapter = AbstractAdapter.new nil, nil
+      end
+
+      def test_in_use?
+        assert_not @adapter.in_use?, 'adapter is not in use'
+        assert @adapter.lease, 'lease adapter'
+        assert @adapter.in_use?, 'adapter is in use'
+      end
+
+      def test_lease_twice
+        assert @adapter.lease, 'should lease adapter'
+        assert_not @adapter.lease, 'should not lease adapter'
+      end
+
+      def test_expire_mutates_in_use
+        assert @adapter.lease, 'lease adapter'
+        assert @adapter.in_use?, 'adapter is in use'
+        @adapter.expire
+        assert_not @adapter.in_use?, 'adapter is in use'
+      end
+
+      def test_close
+        pool = Pool.new(ConnectionSpecification.new({}, nil))
+        pool.insert_connection_for_test! @adapter
+        @adapter.pool = pool
+
+        # Make sure the pool marks the connection in use
+        assert_equal @adapter, pool.connection
+        assert @adapter.in_use?
+
+        # Close should put the adapter back in the pool
+        @adapter.close
+        assert_not @adapter.in_use?
+
+        assert_equal @adapter, pool.connection
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/connection_handler_test.rb b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
new file mode 100644
index 0000000000..3e33b30144
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
@@ -0,0 +1,53 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionHandlerTest < ActiveRecord::TestCase
+      def setup
+        @klass    = Class.new(Base)   { def self.name; 'klass';    end }
+        @subklass = Class.new(@klass) { def self.name; 'subklass'; end }
+
+        @handler = ConnectionHandler.new
+        @pool    = @handler.establish_connection(@klass, Base.connection_pool.spec)
+      end
+
+      def test_retrieve_connection
+        assert @handler.retrieve_connection(@klass)
+      end
+
+      def test_active_connections?
+        assert !@handler.active_connections?
+        assert @handler.retrieve_connection(@klass)
+        assert @handler.active_connections?
+        @handler.clear_active_connections!
+        assert !@handler.active_connections?
+      end
+
+      def test_retrieve_connection_pool_with_ar_base
+        assert_nil @handler.retrieve_connection_pool(ActiveRecord::Base)
+      end
+
+      def test_retrieve_connection_pool
+        assert_not_nil @handler.retrieve_connection_pool(@klass)
+      end
+
+      def test_retrieve_connection_pool_uses_superclass_when_no_subclass_connection
+        assert_not_nil @handler.retrieve_connection_pool(@subklass)
+      end
+
+      def test_retrieve_connection_pool_uses_superclass_pool_after_subclass_establish_and_remove
+        sub_pool = @handler.establish_connection(@subklass, Base.connection_pool.spec)
+        assert_same sub_pool, @handler.retrieve_connection_pool(@subklass)
+
+        @handler.remove_connection @subklass
+        assert_same @pool, @handler.retrieve_connection_pool(@subklass)
+      end
+
+      def test_connection_pools
+        assert_deprecated do
+          assert_equal({ Base.connection_pool.spec => @pool }, @handler.connection_pools)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/connection_specification_test.rb b/activerecord/test/cases/connection_adapters/connection_specification_test.rb
new file mode 100644
index 0000000000..ea2196cda2
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/connection_specification_test.rb
@@ -0,0 +1,12 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionSpecificationTest < ActiveRecord::TestCase
+      def test_dup_deep_copy_config
+        spec = ConnectionSpecification.new({ :a => :b }, "bar")
+        assert_not_equal(spec.config.object_id, spec.dup.config.object_id)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb b/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
new file mode 100644
index 0000000000..e1b2804a18
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
@@ -0,0 +1,204 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class MergeAndResolveDefaultUrlConfigTest < ActiveRecord::TestCase
+      def setup
+        @previous_database_url = ENV.delete("DATABASE_URL")
+      end
+
+      teardown do
+        ENV["DATABASE_URL"] = @previous_database_url
+      end
+
+      def resolve_config(config)
+        ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig.new(config).resolve
+      end
+
+      def resolve_spec(spec, config)
+        ConnectionSpecification::Resolver.new(resolve_config(config)).resolve(spec)
+      end
+
+      def test_resolver_with_database_uri_and_current_env_symbol_key
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+        config   = { "not_production" => {  "adapter" => "not_postgres", "database" => "not_foo" } }
+        actual   = resolve_spec(:default_env, config)
+        expected = { "adapter"=>"postgresql", "database"=>"foo", "host"=>"localhost" }
+        assert_equal expected, actual
+      end
+
+      def test_resolver_with_database_uri_and_and_current_env_string_key
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+        config   = { "default_env" => {  "adapter" => "not_postgres", "database" => "not_foo" } }
+        actual   = assert_deprecated { resolve_spec("default_env", config) }
+        expected = { "adapter"=>"postgresql", "database"=>"foo", "host"=>"localhost" }
+        assert_equal expected, actual
+      end
+
+      def test_resolver_with_database_uri_and_known_key
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+        config   = { "production" => { "adapter" => "not_postgres", "database" => "not_foo", "host" => "localhost" } }
+        actual   = resolve_spec(:production, config)
+        expected = { "adapter"=>"not_postgres", "database"=>"not_foo", "host"=>"localhost" }
+        assert_equal expected, actual
+      end
+
+      def test_resolver_with_database_uri_and_unknown_symbol_key
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+        config   = { "not_production" => {  "adapter" => "not_postgres", "database" => "not_foo" } }
+        assert_raises AdapterNotSpecified do
+          resolve_spec(:production, config)
+        end
+      end
+
+      def test_resolver_with_database_uri_and_unknown_string_key
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+        config   = { "not_production" => {  "adapter" => "not_postgres", "database" => "not_foo" } }
+        assert_deprecated do
+          assert_raises AdapterNotSpecified do
+           resolve_spec("production", config)
+          end
+        end
+      end
+
+      def test_resolver_with_database_uri_and_supplied_url
+        ENV['DATABASE_URL'] = "not-postgres://not-localhost/not_foo"
+        config   = { "production" => {  "adapter" => "also_not_postgres", "database" => "also_not_foo" } }
+        actual   = resolve_spec("postgres://localhost/foo", config)
+        expected = { "adapter"=>"postgresql", "database"=>"foo", "host"=>"localhost" }
+        assert_equal expected, actual
+      end
+
+      def test_jdbc_url
+        config   = { "production" => { "url" => "jdbc:postgres://localhost/foo" } }
+        actual   = resolve_config(config)
+        assert_equal config, actual
+      end
+
+      def test_environment_does_not_exist_in_config_url_does_exist
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+        config      = { "not_default_env" => {  "adapter" => "not_postgres", "database" => "not_foo" } }
+        actual      = resolve_config(config)
+        expect_prod = { "adapter"=>"postgresql", "database"=>"foo", "host"=>"localhost" }
+        assert_equal expect_prod, actual["default_env"]
+      end
+
+      def test_url_with_hyphenated_scheme
+        ENV['DATABASE_URL'] = "ibm-db://localhost/foo"
+        config   = { "default_env" => { "adapter" => "not_postgres", "database" => "not_foo", "host" => "localhost" } }
+        actual   = resolve_spec(:default_env, config)
+        expected = { "adapter"=>"ibm_db", "database"=>"foo", "host"=>"localhost" }
+        assert_equal expected, actual
+      end
+
+      def test_string_connection
+        config   = { "default_env" => "postgres://localhost/foo" }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_url_sub_key
+        config   = { "default_env" => { "url" => "postgres://localhost/foo" } }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_hash
+        config = { "production" => { "adapter" => "postgres", "database" => "foo" } }
+        actual = resolve_config(config)
+        assert_equal config, actual
+      end
+
+      def test_blank
+        config = {}
+        actual = resolve_config(config)
+        assert_equal config, actual
+      end
+
+      def test_blank_with_database_url
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+
+        config   = {}
+        actual   = resolve_config(config)
+        expected = { "adapter"  => "postgresql",
+                     "database" => "foo",
+                     "host"     => "localhost" }
+        assert_equal expected, actual["default_env"]
+        assert_equal nil,      actual["production"]
+        assert_equal nil,      actual["development"]
+        assert_equal nil,      actual["test"]
+        assert_equal nil,      actual[:production]
+        assert_equal nil,      actual[:development]
+        assert_equal nil,      actual[:test]
+      end
+
+      def test_database_url_with_ipv6_host_and_port
+        ENV['DATABASE_URL'] = "postgres://[::1]:5454/foo"
+
+        config   = {}
+        actual   = resolve_config(config)
+        expected = { "adapter"  => "postgresql",
+                     "database" => "foo",
+                     "host"     => "::1",
+                     "port"     => 5454 }
+        assert_equal expected, actual["default_env"]
+      end
+
+      def test_url_sub_key_with_database_url
+        ENV['DATABASE_URL'] = "NOT-POSTGRES://localhost/NOT_FOO"
+
+        config   = { "default_env" => { "url" => "postgres://localhost/foo" } }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                    { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_merge_no_conflicts_with_database_url
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+
+        config   = {"default_env" => { "pool" => "5" } }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost",
+                       "pool"     => "5"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_merge_conflicts_with_database_url
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+
+        config   = {"default_env" => { "adapter" => "NOT-POSTGRES", "database" => "NOT-FOO", "pool" => "5" } }
+        actual   = resolve_config(config)
+        expected = { "default_env" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost",
+                       "pool"     => "5"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb b/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb
new file mode 100644
index 0000000000..d4d67487db
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb
@@ -0,0 +1,61 @@
+require "cases/helper"
+
+if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+module ActiveRecord
+  module ConnectionAdapters
+    class MysqlTypeLookupTest < ActiveRecord::TestCase
+      setup do
+        @connection = ActiveRecord::Base.connection
+      end
+
+      def test_boolean_types
+        emulate_booleans(true) do
+          assert_lookup_type :boolean, 'tinyint(1)'
+          assert_lookup_type :boolean, 'TINYINT(1)'
+        end
+      end
+
+      def test_string_types
+        assert_lookup_type :string, "enum('one', 'two', 'three')"
+        assert_lookup_type :string, "ENUM('one', 'two', 'three')"
+        assert_lookup_type :string, "set('one', 'two', 'three')"
+        assert_lookup_type :string, "SET('one', 'two', 'three')"
+      end
+
+      def test_binary_types
+        assert_lookup_type :binary, 'bit'
+        assert_lookup_type :binary, 'BIT'
+      end
+
+      def test_integer_types
+        emulate_booleans(false) do
+          assert_lookup_type :integer, 'tinyint(1)'
+          assert_lookup_type :integer, 'TINYINT(1)'
+          assert_lookup_type :integer, 'year'
+          assert_lookup_type :integer, 'YEAR'
+        end
+      end
+
+      private
+
+      def assert_lookup_type(type, lookup)
+        cast_type = @connection.type_map.lookup(lookup)
+        assert_equal type, cast_type.type
+      end
+
+      def emulate_booleans(value)
+        old_emulate_booleans = @connection.emulate_booleans
+        change_emulate_booleans(value)
+        yield
+      ensure
+        change_emulate_booleans(old_emulate_booleans)
+      end
+
+      def change_emulate_booleans(value)
+        @connection.emulate_booleans = value
+        @connection.clear_cache!
+      end
+    end
+  end
+end
+end
diff --git a/activerecord/test/cases/connection_adapters/quoting_test.rb b/activerecord/test/cases/connection_adapters/quoting_test.rb
new file mode 100644
index 0000000000..59dcb96ebc
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/quoting_test.rb
@@ -0,0 +1,13 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    module Quoting
+      class QuotingTest < ActiveRecord::TestCase
+        def test_quoting_classes
+          assert_equal "'Object'", AbstractAdapter.new(nil).quote(Object)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/schema_cache_test.rb b/activerecord/test/cases/connection_adapters/schema_cache_test.rb
new file mode 100644
index 0000000000..c7531f5418
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/schema_cache_test.rb
@@ -0,0 +1,56 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class SchemaCacheTest < ActiveRecord::TestCase
+      def setup
+        connection = ActiveRecord::Base.connection
+        @cache     = SchemaCache.new connection
+      end
+
+      def test_primary_key
+        assert_equal 'id', @cache.primary_keys('posts')
+      end
+
+      def test_primary_key_for_non_existent_table
+        assert_nil @cache.primary_keys('omgponies')
+      end
+
+      def test_caches_columns
+        columns = @cache.columns('posts')
+        assert_equal columns, @cache.columns('posts')
+      end
+
+      def test_caches_columns_hash
+        columns_hash = @cache.columns_hash('posts')
+        assert_equal columns_hash, @cache.columns_hash('posts')
+      end
+
+      def test_clearing
+        @cache.columns('posts')
+        @cache.columns_hash('posts')
+        @cache.tables('posts')
+        @cache.primary_keys('posts')
+
+        @cache.clear!
+
+        assert_equal 0, @cache.size
+      end
+
+      def test_dump_and_load
+        @cache.columns('posts')
+        @cache.columns_hash('posts')
+        @cache.tables('posts')
+        @cache.primary_keys('posts')
+
+        @cache = Marshal.load(Marshal.dump(@cache))
+
+        assert_equal 11, @cache.columns('posts').size
+        assert_equal 11, @cache.columns_hash('posts').size
+        assert @cache.tables('posts')
+        assert_equal 'id', @cache.primary_keys('posts')
+      end
+
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/type_lookup_test.rb b/activerecord/test/cases/connection_adapters/type_lookup_test.rb
new file mode 100644
index 0000000000..d5c1dc1e5d
--- /dev/null
+++ b/activerecord/test/cases/connection_adapters/type_lookup_test.rb
@@ -0,0 +1,101 @@
+require "cases/helper"
+
+unless current_adapter?(:PostgreSQLAdapter) # PostgreSQL does not use type strigns for lookup
+module ActiveRecord
+  module ConnectionAdapters
+    class TypeLookupTest < ActiveRecord::TestCase
+      setup do
+        @connection = ActiveRecord::Base.connection
+      end
+
+      def test_boolean_types
+        assert_lookup_type :boolean, 'boolean'
+        assert_lookup_type :boolean, 'BOOLEAN'
+      end
+
+      def test_string_types
+        assert_lookup_type :string, 'char'
+        assert_lookup_type :string, 'varchar'
+        assert_lookup_type :string, 'VARCHAR'
+        assert_lookup_type :string, 'varchar(255)'
+        assert_lookup_type :string, 'character varying'
+      end
+
+      def test_binary_types
+        assert_lookup_type :binary, 'binary'
+        assert_lookup_type :binary, 'BINARY'
+        assert_lookup_type :binary, 'blob'
+        assert_lookup_type :binary, 'BLOB'
+      end
+
+      def test_text_types
+        assert_lookup_type :text, 'text'
+        assert_lookup_type :text, 'TEXT'
+        assert_lookup_type :text, 'clob'
+        assert_lookup_type :text, 'CLOB'
+      end
+
+      def test_date_types
+        assert_lookup_type :date, 'date'
+        assert_lookup_type :date, 'DATE'
+      end
+
+      def test_time_types
+        assert_lookup_type :time, 'time'
+        assert_lookup_type :time, 'TIME'
+      end
+
+      def test_datetime_types
+        assert_lookup_type :datetime, 'datetime'
+        assert_lookup_type :datetime, 'DATETIME'
+        assert_lookup_type :datetime, 'timestamp'
+        assert_lookup_type :datetime, 'TIMESTAMP'
+      end
+
+      def test_decimal_types
+        assert_lookup_type :decimal, 'decimal'
+        assert_lookup_type :decimal, 'decimal(2,8)'
+        assert_lookup_type :decimal, 'DECIMAL'
+        assert_lookup_type :decimal, 'numeric'
+        assert_lookup_type :decimal, 'numeric(2,8)'
+        assert_lookup_type :decimal, 'NUMERIC'
+        assert_lookup_type :decimal, 'number'
+        assert_lookup_type :decimal, 'number(2,8)'
+        assert_lookup_type :decimal, 'NUMBER'
+      end
+
+      def test_float_types
+        assert_lookup_type :float, 'float'
+        assert_lookup_type :float, 'FLOAT'
+        assert_lookup_type :float, 'double'
+        assert_lookup_type :float, 'DOUBLE'
+      end
+
+      def test_integer_types
+        assert_lookup_type :integer, 'integer'
+        assert_lookup_type :integer, 'INTEGER'
+        assert_lookup_type :integer, 'tinyint'
+        assert_lookup_type :integer, 'smallint'
+        assert_lookup_type :integer, 'bigint'
+      end
+
+      def test_decimal_without_scale
+        types = %w{decimal(2) decimal(2,0) numeric(2) numeric(2,0) number(2) number(2,0)}
+        types.each do |type|
+          cast_type = @connection.type_map.lookup(type)
+
+          assert_equal :decimal, cast_type.type
+          assert_equal 2, cast_type.type_cast_from_user(2.1)
+        end
+      end
+
+      private
+
+      def assert_lookup_type(type, lookup)
+        cast_type = @connection.type_map.lookup(lookup)
+        assert_equal type, cast_type.type
+      end
+    end
+  end
+end
+end
diff --git a/activerecord/test/cases/connection_management_test.rb b/activerecord/test/cases/connection_management_test.rb
new file mode 100644
index 0000000000..77d9ae9b8e
--- /dev/null
+++ b/activerecord/test/cases/connection_management_test.rb
@@ -0,0 +1,114 @@
+require "cases/helper"
+require "rack"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionManagementTest < ActiveRecord::TestCase
+      class App
+        attr_reader :calls
+        def initialize
+          @calls = []
+        end
+
+        def call(env)
+          @calls << env
+          [200, {}, ['hi mom']]
+        end
+      end
+
+      def setup
+        @env = {}
+        @app = App.new
+        @management = ConnectionManagement.new(@app)
+
+        # make sure we have an active connection
+        assert ActiveRecord::Base.connection
+        assert ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      if Process.respond_to?(:fork)
+        def test_connection_pool_per_pid
+          object_id = ActiveRecord::Base.connection.object_id
+
+          rd, wr = IO.pipe
+          rd.binmode
+          wr.binmode
+
+          pid = fork {
+            rd.close
+            wr.write Marshal.dump ActiveRecord::Base.connection.object_id
+            wr.close
+            exit!
+          }
+
+          wr.close
+
+          Process.waitpid pid
+          assert_not_equal object_id, Marshal.load(rd.read)
+          rd.close
+        end
+      end
+
+      def test_app_delegation
+        manager = ConnectionManagement.new(@app)
+
+        manager.call @env
+        assert_equal [@env], @app.calls
+      end
+
+      def test_connections_are_active_after_call
+        @management.call(@env)
+        assert ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      def test_body_responds_to_each
+        _, _, body = @management.call(@env)
+        bits = []
+        body.each { |bit| bits << bit }
+        assert_equal ['hi mom'], bits
+      end
+
+      def test_connections_are_cleared_after_body_close
+        _, _, body = @management.call(@env)
+        body.close
+        assert !ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      def test_active_connections_are_not_cleared_on_body_close_during_test
+        @env['rack.test'] = true
+        _, _, body = @management.call(@env)
+        body.close
+        assert ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      def test_connections_closed_if_exception
+        app       = Class.new(App) { def call(env); raise NotImplementedError; end }.new
+        explosive = ConnectionManagement.new(app)
+        assert_raises(NotImplementedError) { explosive.call(@env) }
+        assert !ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      def test_connections_not_closed_if_exception_and_test
+        @env['rack.test'] = true
+        app               = Class.new(App) { def call(env); raise; end }.new
+        explosive         = ConnectionManagement.new(app)
+        assert_raises(RuntimeError) { explosive.call(@env) }
+        assert ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      test "doesn't clear active connections when running in a test case" do
+        @env['rack.test'] = true
+        @management.call(@env)
+        assert ActiveRecord::Base.connection_handler.active_connections?
+      end
+
+      test "proxy is polite to it's body and responds to it" do
+        body = Class.new(String) { def to_path; "/path"; end }.new
+        app = lambda { |_| [200, {}, body] }
+        response_body = ConnectionManagement.new(app).call(@env)[2]
+        assert response_body.respond_to?(:to_path)
+        assert_equal response_body.to_path, "/path"
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_pool_test.rb b/activerecord/test/cases/connection_pool_test.rb
new file mode 100644
index 0000000000..8d15a76735
--- /dev/null
+++ b/activerecord/test/cases/connection_pool_test.rb
@@ -0,0 +1,346 @@
+require "cases/helper"
+require 'active_support/concurrency/latch'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionPoolTest < ActiveRecord::TestCase
+      attr_reader :pool
+
+      def setup
+        super
+
+        # Keep a duplicate pool so we do not bother others
+        @pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+
+        if in_memory_db?
+          # Separate connections to an in-memory database create an entirely new database,
+          # with an empty schema etc, so we just stub out this schema on the fly.
+          @pool.with_connection do |connection|
+            connection.create_table :posts do |t|
+              t.integer :cololumn
+            end
+          end
+        end
+      end
+
+      teardown do
+        @pool.disconnect!
+      end
+
+      def active_connections(pool)
+        pool.connections.find_all(&:in_use?)
+      end
+
+      def test_checkout_after_close
+        connection = pool.connection
+        assert connection.in_use?
+
+        connection.close
+        assert !connection.in_use?
+
+        assert pool.connection.in_use?
+      end
+
+      def test_released_connection_moves_between_threads
+        thread_conn = nil
+
+        Thread.new {
+          pool.with_connection do |conn|
+            thread_conn = conn
+          end
+        }.join
+
+        assert thread_conn
+
+        Thread.new {
+          pool.with_connection do |conn|
+            assert_equal thread_conn, conn
+          end
+        }.join
+      end
+
+      def test_with_connection
+        assert_equal 0, active_connections(pool).size
+
+        main_thread = pool.connection
+        assert_equal 1, active_connections(pool).size
+
+        Thread.new {
+          pool.with_connection do |conn|
+            assert conn
+            assert_equal 2, active_connections(pool).size
+          end
+          assert_equal 1, active_connections(pool).size
+        }.join
+
+        main_thread.close
+        assert_equal 0, active_connections(pool).size
+      end
+
+      def test_active_connection_in_use
+        assert !pool.active_connection?
+        main_thread = pool.connection
+
+        assert pool.active_connection?
+
+        main_thread.close
+
+        assert !pool.active_connection?
+      end
+
+      def test_full_pool_exception
+        @pool.size.times { @pool.checkout }
+        assert_raises(ConnectionTimeoutError) do
+          @pool.checkout
+        end
+      end
+
+      def test_full_pool_blocks
+        cs = @pool.size.times.map { @pool.checkout }
+        t = Thread.new { @pool.checkout }
+
+        # make sure our thread is in the timeout section
+        Thread.pass until t.status == "sleep"
+
+        connection = cs.first
+        connection.close
+        assert_equal connection, t.join.value
+      end
+
+      def test_removing_releases_latch
+        cs = @pool.size.times.map { @pool.checkout }
+        t = Thread.new { @pool.checkout }
+
+        # make sure our thread is in the timeout section
+        Thread.pass until t.status == "sleep"
+
+        connection = cs.first
+        @pool.remove connection
+        assert_respond_to t.join.value, :execute
+        connection.close
+      end
+
+      def test_reap_and_active
+        @pool.checkout
+        @pool.checkout
+        @pool.checkout
+
+        connections = @pool.connections.dup
+
+        @pool.reap
+
+        assert_equal connections.length, @pool.connections.length
+      end
+
+      def test_reap_inactive
+        ready = ActiveSupport::Concurrency::Latch.new
+        @pool.checkout
+        child = Thread.new do
+          @pool.checkout
+          @pool.checkout
+          ready.release
+          Thread.stop
+        end
+        ready.await
+
+        assert_equal 3, active_connections(@pool).size
+
+        child.terminate
+        child.join
+        @pool.reap
+
+        assert_equal 1, active_connections(@pool).size
+      ensure
+        @pool.connections.each(&:close)
+      end
+
+      def test_remove_connection
+        conn = @pool.checkout
+        assert conn.in_use?
+
+        length = @pool.connections.length
+        @pool.remove conn
+        assert conn.in_use?
+        assert_equal(length - 1, @pool.connections.length)
+      ensure
+        conn.close
+      end
+
+      def test_remove_connection_for_thread
+        conn = @pool.connection
+        @pool.remove conn
+        assert_not_equal(conn, @pool.connection)
+      ensure
+        conn.close if conn
+      end
+
+      def test_active_connection?
+        assert !@pool.active_connection?
+        assert @pool.connection
+        assert @pool.active_connection?
+        @pool.release_connection
+        assert !@pool.active_connection?
+      end
+
+      def test_checkout_behaviour
+        pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+        connection = pool.connection
+        assert_not_nil connection
+        threads = []
+        4.times do |i|
+          threads << Thread.new(i) do
+            connection = pool.connection
+            assert_not_nil connection
+            connection.close
+          end
+        end
+
+        threads.each(&:join)
+
+        Thread.new do
+          assert pool.connection
+          pool.connection.close
+        end.join
+      end
+
+      # The connection pool is "fair" if threads waiting for
+      # connections receive them the order in which they began
+      # waiting.  This ensures that we don't timeout one HTTP request
+      # even while well under capacity in a multi-threaded environment
+      # such as a Java servlet container.
+      #
+      # We don't need strict fairness: if two connections become
+      # available at the same time, it's fine of two threads that were
+      # waiting acquire the connections out of order.
+      #
+      # Thus this test prepares waiting threads and then trickles in
+      # available connections slowly, ensuring the wakeup order is
+      # correct in this case.
+      def test_checkout_fairness
+        @pool.instance_variable_set(:@size, 10)
+        expected = (1..@pool.size).to_a.freeze
+        # check out all connections so our threads start out waiting
+        conns = expected.map { @pool.checkout }
+        mutex = Mutex.new
+        order = []
+        errors = []
+
+        threads = expected.map do |i|
+          t = Thread.new {
+            begin
+              @pool.checkout # never checked back in
+              mutex.synchronize { order << i }
+            rescue => e
+              mutex.synchronize { errors << e }
+            end
+          }
+          Thread.pass until t.status == "sleep"
+          t
+        end
+
+        # this should wake up the waiting threads one by one in order
+        conns.each { |conn| @pool.checkin(conn); sleep 0.1 }
+
+        threads.each(&:join)
+
+        raise errors.first if errors.any?
+
+        assert_equal(expected, order)
+      end
+
+      # As mentioned in #test_checkout_fairness, we don't care about
+      # strict fairness.  This test creates two groups of threads:
+      # group1 whose members all start waiting before any thread in
+      # group2.  Enough connections are checked in to wakeup all
+      # group1 threads, and the fact that only group1 and no group2
+      # threads acquired a connection is enforced.
+      def test_checkout_fairness_by_group
+        @pool.instance_variable_set(:@size, 10)
+        # take all the connections
+        conns = (1..10).map { @pool.checkout }
+        mutex = Mutex.new
+        successes = []    # threads that successfully got a connection
+        errors = []
+
+        make_thread = proc do |i|
+          t = Thread.new {
+            begin
+              @pool.checkout # never checked back in
+              mutex.synchronize { successes << i }
+            rescue => e
+              mutex.synchronize { errors << e }
+            end
+          }
+          Thread.pass until t.status == "sleep"
+          t
+        end
+
+        # all group1 threads start waiting before any in group2
+        group1 = (1..5).map(&make_thread)
+        group2 = (6..10).map(&make_thread)
+
+        # checkin n connections back to the pool
+        checkin = proc do |n|
+          n.times do
+            c = conns.pop
+            @pool.checkin(c)
+          end
+        end
+
+        checkin.call(group1.size)         # should wake up all group1
+
+        loop do
+          sleep 0.1
+          break if mutex.synchronize { (successes.size + errors.size) == group1.size }
+        end
+
+        winners = mutex.synchronize { successes.dup }
+        checkin.call(group2.size)         # should wake up everyone remaining
+
+        group1.each(&:join)
+        group2.each(&:join)
+
+        assert_equal((1..group1.size).to_a, winners.sort)
+
+        if errors.any?
+          raise errors.first
+        end
+      end
+
+      def test_automatic_reconnect=
+        pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+        assert pool.automatic_reconnect
+        assert pool.connection
+
+        pool.disconnect!
+        assert pool.connection
+
+        pool.disconnect!
+        pool.automatic_reconnect = false
+
+        assert_raises(ConnectionNotEstablished) do
+          pool.connection
+        end
+
+        assert_raises(ConnectionNotEstablished) do
+          pool.with_connection
+        end
+      end
+
+      def test_pool_sets_connection_visitor
+        assert @pool.connection.visitor.is_a?(Arel::Visitors::ToSql)
+      end
+
+      # make sure exceptions are thrown when establish_connection
+      # is called with an anonymous class
+      def test_anonymous_class_exception
+        anonymous = Class.new(ActiveRecord::Base)
+        handler = ActiveRecord::Base.connection_handler
+
+        assert_raises(RuntimeError) {
+          handler.establish_connection anonymous, nil
+        }
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_specification/resolver_test.rb b/activerecord/test/cases/connection_specification/resolver_test.rb
new file mode 100644
index 0000000000..3c2f5d4219
--- /dev/null
+++ b/activerecord/test/cases/connection_specification/resolver_test.rb
@@ -0,0 +1,116 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionSpecification
+      class ResolverTest < ActiveRecord::TestCase
+        def resolve(spec, config={})
+          Resolver.new(config).resolve(spec)
+        end
+
+        def spec(spec, config={})
+          Resolver.new(config).spec(spec)
+        end
+
+        def test_url_invalid_adapter
+          error = assert_raises(LoadError) do
+            spec 'ridiculous://foo?encoding=utf8'
+          end
+
+          assert_match "Could not load 'active_record/connection_adapters/ridiculous_adapter'", error.message
+        end
+
+        # The abstract adapter is used simply to bypass the bit of code that
+        # checks that the adapter file can be required in.
+
+        def test_url_from_environment
+          spec = resolve :production, 'production' => 'abstract://foo?encoding=utf8'
+          assert_equal({
+            "adapter"  =>  "abstract",
+            "host"     =>  "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+        def test_url_sub_key
+          spec = resolve :production, 'production' => {"url" => 'abstract://foo?encoding=utf8'}
+          assert_equal({
+            "adapter"  => "abstract",
+            "host"     => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+        def test_url_sub_key_merges_correctly
+          hash = {"url" => 'abstract://foo?encoding=utf8&', "adapter" => "sqlite3", "host" => "bar", "pool" => "3"}
+          spec = resolve :production, 'production' => hash
+          assert_equal({
+            "adapter"  => "abstract",
+            "host"     => "foo",
+            "encoding" => "utf8",
+            "pool"     => "3" }, spec)
+        end
+
+        def test_url_host_no_db
+          spec = resolve 'abstract://foo?encoding=utf8'
+          assert_equal({
+            "adapter"  => "abstract",
+            "host"     => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+        def test_url_host_db
+          spec = resolve 'abstract://foo/bar?encoding=utf8'
+          assert_equal({
+            "adapter"  => "abstract",
+            "database" => "bar",
+            "host"     => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+        def test_url_port
+          spec = resolve 'abstract://foo:123?encoding=utf8'
+          assert_equal({
+            "adapter"  => "abstract",
+            "port"     => 123,
+            "host"     => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+        def test_encoded_password
+          password = 'am@z1ng_p@ssw0rd#!'
+          encoded_password = URI.encode_www_form_component(password)
+          spec = resolve "abstract://foo:#{encoded_password}@localhost/bar"
+          assert_equal password, spec["password"]
+        end
+
+        def test_url_with_authority_for_sqlite3
+          spec = resolve 'sqlite3:///foo_test'
+          assert_equal('/foo_test', spec["database"])
+        end
+
+        def test_url_absolute_path_for_sqlite3
+          spec = resolve 'sqlite3:/foo_test'
+          assert_equal('/foo_test', spec["database"])
+        end
+
+        def test_url_relative_path_for_sqlite3
+          spec = resolve 'sqlite3:foo_test'
+          assert_equal('foo_test', spec["database"])
+        end
+
+        def test_url_memory_db_for_sqlite3
+          spec = resolve 'sqlite3::memory:'
+          assert_equal(':memory:', spec["database"])
+        end
+
+        def test_url_sub_key_for_sqlite3
+          spec = resolve :production, 'production' => {"url" => 'sqlite3:foo?encoding=utf8'}
+          assert_equal({
+            "adapter"  => "sqlite3",
+            "database" => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/core_test.rb b/activerecord/test/cases/core_test.rb
new file mode 100644
index 0000000000..715d92af99
--- /dev/null
+++ b/activerecord/test/cases/core_test.rb
@@ -0,0 +1,101 @@
+require 'cases/helper'
+require 'models/person'
+require 'models/topic'
+require 'pp'
+require 'active_support/core_ext/string/strip'
+
+class NonExistentTable < ActiveRecord::Base; end
+
+class CoreTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  def test_inspect_class
+    assert_equal 'ActiveRecord::Base', ActiveRecord::Base.inspect
+    assert_equal 'LoosePerson(abstract)', LoosePerson.inspect
+    assert_match(/^Topic\(id: integer, title: string/, Topic.inspect)
+  end
+
+  def test_inspect_instance
+    topic = topics(:first)
+    assert_equal %(#<Topic id: 1, title: "The First Topic", author_name: "David", author_email_address: "david@loudthinking.com", written_on: "#{topic.written_on.to_s(:db)}", bonus_time: "#{topic.bonus_time.to_s(:db)}", last_read: "#{topic.last_read.to_s(:db)}", content: "Have a nice day", important: nil, approved: false, replies_count: 1, unique_replies_count: 0, parent_id: nil, parent_title: nil, type: nil, group: nil, created_at: "#{topic.created_at.to_s(:db)}", updated_at: "#{topic.updated_at.to_s(:db)}">), topic.inspect
+  end
+
+  def test_inspect_new_instance
+    assert_match(/Topic id: nil/, Topic.new.inspect)
+  end
+
+  def test_inspect_limited_select_instance
+    assert_equal %(#<Topic id: 1>), Topic.all.merge!(:select => 'id', :where => 'id = 1').first.inspect
+    assert_equal %(#<Topic id: 1, title: "The First Topic">), Topic.all.merge!(:select => 'id, title', :where => 'id = 1').first.inspect
+  end
+
+  def test_inspect_class_without_table
+    assert_equal "NonExistentTable(Table doesn't exist)", NonExistentTable.inspect
+  end
+
+  def test_pretty_print_new
+    topic = Topic.new
+    actual = ''
+    PP.pp(topic, StringIO.new(actual))
+    expected = <<-PRETTY.strip_heredoc
+    #<Topic:0xXXXXXX
+     id: nil,
+     title: nil,
+     author_name: nil,
+     author_email_address: "test@test.com",
+     written_on: nil,
+     bonus_time: nil,
+     last_read: nil,
+     content: nil,
+     important: nil,
+     approved: true,
+     replies_count: 0,
+     unique_replies_count: 0,
+     parent_id: nil,
+     parent_title: nil,
+     type: nil,
+     group: nil,
+     created_at: nil,
+     updated_at: nil>
+    PRETTY
+    assert actual.start_with?(expected.split('XXXXXX').first)
+    assert actual.end_with?(expected.split('XXXXXX').last)
+  end
+
+  def test_pretty_print_persisted
+    topic = topics(:first)
+    actual = ''
+    PP.pp(topic, StringIO.new(actual))
+    expected = <<-PRETTY.strip_heredoc
+    #<Topic:0x\\w+
+     id: 1,
+     title: "The First Topic",
+     author_name: "David",
+     author_email_address: "david@loudthinking.com",
+     written_on: 2003-07-16 14:28:11 UTC,
+     bonus_time: 2000-01-01 14:28:00 UTC,
+     last_read: Thu, 15 Apr 2004,
+     content: "Have a nice day",
+     important: nil,
+     approved: false,
+     replies_count: 1,
+     unique_replies_count: 0,
+     parent_id: nil,
+     parent_title: nil,
+     type: nil,
+     group: nil,
+     created_at: [^,]+,
+     updated_at: [^,>]+>
+    PRETTY
+    assert_match(/\A#{expected}\z/, actual)
+  end
+
+  def test_pretty_print_uninitialized
+    topic = Topic.allocate
+    actual = ''
+    PP.pp(topic, StringIO.new(actual))
+    expected = "#<Topic:XXXXXX not initialized>\n"
+    assert actual.start_with?(expected.split('XXXXXX').first)
+    assert actual.end_with?(expected.split('XXXXXX').last)
+  end
+end
diff --git a/activerecord/test/cases/counter_cache_test.rb b/activerecord/test/cases/counter_cache_test.rb
new file mode 100644
index 0000000000..07a182070b
--- /dev/null
+++ b/activerecord/test/cases/counter_cache_test.rb
@@ -0,0 +1,183 @@
+require 'cases/helper'
+require 'models/topic'
+require 'models/car'
+require 'models/wheel'
+require 'models/engine'
+require 'models/reply'
+require 'models/category'
+require 'models/categorization'
+require 'models/dog'
+require 'models/dog_lover'
+require 'models/person'
+require 'models/friendship'
+require 'models/subscriber'
+require 'models/subscription'
+require 'models/book'
+
+class CounterCacheTest < ActiveRecord::TestCase
+  fixtures :topics, :categories, :categorizations, :cars, :dogs, :dog_lovers, :people, :friendships, :subscribers, :subscriptions, :books
+
+  class ::SpecialTopic < ::Topic
+    has_many :special_replies, :foreign_key => 'parent_id'
+    has_many :lightweight_special_replies, -> { select('topics.id, topics.title') }, :foreign_key => 'parent_id', :class_name => 'SpecialReply'
+  end
+
+  class ::SpecialReply < ::Reply
+    belongs_to :special_topic, :foreign_key => 'parent_id', :counter_cache => 'replies_count'
+  end
+
+  setup do
+    @topic = Topic.find(1)
+  end
+
+  test "increment counter" do
+    assert_difference '@topic.reload.replies_count' do
+      Topic.increment_counter(:replies_count, @topic.id)
+    end
+  end
+
+  test "decrement counter" do
+    assert_difference '@topic.reload.replies_count', -1 do
+      Topic.decrement_counter(:replies_count, @topic.id)
+    end
+  end
+
+  test "reset counters" do
+    # throw the count off by 1
+    Topic.increment_counter(:replies_count, @topic.id)
+
+    # check that it gets reset
+    assert_difference '@topic.reload.replies_count', -1 do
+      Topic.reset_counters(@topic.id, :replies)
+    end
+  end
+
+  test "reset counters by counter name" do
+    # throw the count off by 1
+    Topic.increment_counter(:replies_count, @topic.id)
+
+    # check that it gets reset
+    assert_difference '@topic.reload.replies_count', -1 do
+      Topic.reset_counters(@topic.id, :replies_count)
+    end
+  end
+
+  test 'reset multiple counters' do
+    Topic.update_counters @topic.id, replies_count: 1, unique_replies_count: 1
+    assert_difference ['@topic.reload.replies_count', '@topic.reload.unique_replies_count'], -1 do
+      Topic.reset_counters(@topic.id, :replies, :unique_replies)
+    end
+  end
+
+  test "reset counters with string argument" do
+    Topic.increment_counter('replies_count', @topic.id)
+
+    assert_difference '@topic.reload.replies_count', -1 do
+      Topic.reset_counters(@topic.id, 'replies')
+    end
+  end
+
+  test "reset counters with modularized and camelized classnames" do
+    special = SpecialTopic.create!(:title => 'Special')
+    SpecialTopic.increment_counter(:replies_count, special.id)
+
+    assert_difference 'special.reload.replies_count', -1 do
+      SpecialTopic.reset_counters(special.id, :special_replies)
+    end
+  end
+
+  test "reset counter with belongs_to which has class_name" do
+    car = cars(:honda)
+    assert_nothing_raised do
+      Car.reset_counters(car.id, :engines)
+    end
+    assert_nothing_raised do
+      Car.reset_counters(car.id, :wheels)
+    end
+  end
+
+  test "reset the right counter if two have the same class_name" do
+    david = dog_lovers(:david)
+
+    DogLover.increment_counter(:bred_dogs_count, david.id)
+    DogLover.increment_counter(:trained_dogs_count, david.id)
+
+    assert_difference 'david.reload.bred_dogs_count', -1 do
+      DogLover.reset_counters(david.id, :bred_dogs)
+    end
+    assert_difference 'david.reload.trained_dogs_count', -1 do
+      DogLover.reset_counters(david.id, :trained_dogs)
+    end
+  end
+
+  test "update counter with initial null value" do
+    category = categories(:general)
+    assert_equal 2, category.categorizations.count
+    assert_nil category.categorizations_count
+
+    Category.update_counters(category.id, :categorizations_count => category.categorizations.count)
+    assert_equal 2, category.reload.categorizations_count
+  end
+
+  test "update counter for decrement" do
+    assert_difference '@topic.reload.replies_count', -3 do
+      Topic.update_counters(@topic.id, :replies_count => -3)
+    end
+  end
+
+  test "update counters of multiple records" do
+    t1, t2 = topics(:first, :second)
+
+    assert_difference ['t1.reload.replies_count', 't2.reload.replies_count'], 2 do
+      Topic.update_counters([t1.id, t2.id], :replies_count => 2)
+    end
+  end
+
+  test 'update multiple counters' do
+    assert_difference ['@topic.reload.replies_count', '@topic.reload.unique_replies_count'], 2 do
+      Topic.update_counters @topic.id, replies_count: 2, unique_replies_count: 2
+    end
+  end
+
+  test "update other counters on parent destroy" do
+    david, joanna = dog_lovers(:david, :joanna)
+    joanna = joanna # squelch a warning
+
+    assert_difference 'joanna.reload.dogs_count', -1 do
+      david.destroy
+    end
+  end
+
+  test "reset the right counter if two have the same foreign key" do
+    michael = people(:michael)
+    assert_nothing_raised(ActiveRecord::StatementInvalid) do
+      Person.reset_counters(michael.id, :friends_too)
+    end
+  end
+
+  test "reset counter of has_many :through association" do
+    subscriber = subscribers('second')
+    Subscriber.reset_counters(subscriber.id, 'books')
+    Subscriber.increment_counter('books_count', subscriber.id)
+
+    assert_difference 'subscriber.reload.books_count', -1 do
+      Subscriber.reset_counters(subscriber.id, 'books')
+    end
+  end
+
+  test "the passed symbol needs to be an association name or counter name" do
+    e = assert_raises(ArgumentError) do
+      Topic.reset_counters(@topic.id, :undefined_count)
+    end
+    assert_equal "'Topic' has no association called 'undefined_count'", e.message
+  end
+
+  test "reset counter works with select declared on association" do
+    special = SpecialTopic.create!(:title => 'Special')
+    SpecialTopic.increment_counter(:replies_count, special.id)
+
+    assert_difference 'special.reload.replies_count', -1 do
+      SpecialTopic.reset_counters(special.id, :lightweight_special_replies)
+    end
+  end
+end
diff --git a/activerecord/test/cases/custom_locking_test.rb b/activerecord/test/cases/custom_locking_test.rb
new file mode 100644
index 0000000000..e8290297e3
--- /dev/null
+++ b/activerecord/test/cases/custom_locking_test.rb
@@ -0,0 +1,17 @@
+require "cases/helper"
+require 'models/person'
+
+module ActiveRecord
+  class CustomLockingTest < ActiveRecord::TestCase
+    fixtures :people
+
+    def test_custom_lock
+      if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+        assert_match 'SHARE MODE', Person.lock('LOCK IN SHARE MODE').to_sql
+        assert_sql(/LOCK IN SHARE MODE/) do
+          Person.all.merge!(:lock => 'LOCK IN SHARE MODE').find(1)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/database_statements_test.rb b/activerecord/test/cases/database_statements_test.rb
new file mode 100644
index 0000000000..c689e97d83
--- /dev/null
+++ b/activerecord/test/cases/database_statements_test.rb
@@ -0,0 +1,19 @@
+require "cases/helper"
+
+class DatabaseStatementsTest < ActiveRecord::TestCase
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  def test_insert_should_return_the_inserted_id
+    # Oracle adapter uses prefetched primary key values from sequence and passes them to connection adapter insert method
+    if current_adapter?(:OracleAdapter)
+      sequence_name = "accounts_seq"
+      id_value = @connection.next_sequence_value(sequence_name)
+      id = @connection.insert("INSERT INTO accounts (id, firm_id,credit_limit) VALUES (accounts_seq.nextval,42,5000)", nil, :id, id_value, sequence_name)
+    else
+      id = @connection.insert("INSERT INTO accounts (firm_id,credit_limit) VALUES (42,5000)")
+    end
+    assert_not_nil id
+  end
+end
diff --git a/activerecord/test/cases/date_time_test.rb b/activerecord/test/cases/date_time_test.rb
new file mode 100644
index 0000000000..c0491bbee5
--- /dev/null
+++ b/activerecord/test/cases/date_time_test.rb
@@ -0,0 +1,43 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/task'
+
+class DateTimeTest < ActiveRecord::TestCase
+  def test_saves_both_date_and_time
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :utc do
+        time_values = [1807, 2, 10, 15, 30, 45]
+        # create DateTime value with local time zone offset
+        local_offset = Rational(Time.local(*time_values).utc_offset, 86400)
+        now = DateTime.civil(*(time_values + [local_offset]))
+
+        task = Task.new
+        task.starting = now
+        task.save!
+
+        # check against Time.local, since some platforms will return a Time instead of a DateTime
+        assert_equal Time.local(*time_values), Task.find(task.id).starting
+      end
+    end
+  end
+
+  def test_assign_empty_date_time
+    task = Task.new
+    task.starting = ''
+    task.ending = nil
+    assert_nil task.starting
+    assert_nil task.ending
+  end
+
+  def test_assign_empty_date
+    topic = Topic.new
+    topic.last_read = ''
+    assert_nil topic.last_read
+  end
+
+  def test_assign_empty_time
+    topic = Topic.new
+    topic.bonus_time = ''
+    assert_nil topic.bonus_time
+  end
+end
diff --git a/activerecord/test/cases/defaults_test.rb b/activerecord/test/cases/defaults_test.rb
new file mode 100644
index 0000000000..c089e63128
--- /dev/null
+++ b/activerecord/test/cases/defaults_test.rb
@@ -0,0 +1,219 @@
+require "cases/helper"
+require 'models/default'
+require 'models/entrant'
+
+class DefaultTest < ActiveRecord::TestCase
+  def test_nil_defaults_for_not_null_columns
+    column_defaults =
+      if current_adapter?(:MysqlAdapter) && (Mysql.client_version < 50051 || (50100..50122).include?(Mysql.client_version))
+        { 'id' => nil, 'name' => '',  'course_id' => nil }
+      else
+        { 'id' => nil, 'name' => nil, 'course_id' => nil }
+      end
+
+    column_defaults.each do |name, default|
+      column = Entrant.columns_hash[name]
+      assert !column.null, "#{name} column should be NOT NULL"
+      assert_equal default, column.default, "#{name} column should be DEFAULT #{default.inspect}"
+    end
+  end
+
+  if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
+    def test_default_integers
+      default = Default.new
+      assert_instance_of Fixnum, default.positive_integer
+      assert_equal 1, default.positive_integer
+      assert_instance_of Fixnum, default.negative_integer
+      assert_equal(-1, default.negative_integer)
+      assert_instance_of BigDecimal, default.decimal_number
+      assert_equal BigDecimal.new("2.78"), default.decimal_number
+    end
+  end
+
+  if current_adapter?(:PostgreSQLAdapter)
+    def test_multiline_default_text
+      # older postgres versions represent the default with escapes ("\\012" for a newline)
+      assert( "--- []\n\n" == Default.columns_hash['multiline_default'].default ||
+               "--- []\\012\\012" == Default.columns_hash['multiline_default'].default)
+    end
+  end
+end
+
+class DefaultStringsTest < ActiveRecord::TestCase
+  class DefaultString < ActiveRecord::Base; end
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :default_strings do |t|
+      t.string :string_col, default: "Smith"
+      t.string :string_col_with_quotes, default: "O'Connor"
+    end
+    DefaultString.reset_column_information
+  end
+
+  def test_default_strings
+    assert_equal "Smith", DefaultString.new.string_col
+  end
+
+  def test_default_strings_containing_single_quotes
+    assert_equal "O'Connor", DefaultString.new.string_col_with_quotes
+  end
+
+  teardown do
+    @connection.drop_table :default_strings
+  end
+end
+
+if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+  class DefaultsTestWithoutTransactionalFixtures < ActiveRecord::TestCase
+    # ActiveRecord::Base#create! (and #save and other related methods) will
+    # open a new transaction. When in transactional fixtures mode, this will
+    # cause Active Record to create a new savepoint. However, since MySQL doesn't
+    # support DDL transactions, creating a table will result in any created
+    # savepoints to be automatically released. This in turn causes the savepoint
+    # release code in AbstractAdapter#transaction to fail.
+    #
+    # We don't want that to happen, so we disable transactional fixtures here.
+    self.use_transactional_fixtures = false
+
+    def using_strict(strict)
+      connection = ActiveRecord::Base.remove_connection
+      ActiveRecord::Base.establish_connection connection.merge(strict: strict)
+      yield
+    ensure
+      ActiveRecord::Base.remove_connection
+      ActiveRecord::Base.establish_connection connection
+    end
+
+    # MySQL cannot have defaults on text/blob columns. It reports the
+    # default value as null.
+    #
+    # Despite this, in non-strict mode, MySQL will use an empty string
+    # as the default value of the field, if no other value is
+    # specified.
+    #
+    # Therefore, in non-strict mode, we want column.default to report
+    # an empty string as its default, to be consistent with that.
+    #
+    # In strict mode, column.default should be nil.
+    def test_mysql_text_not_null_defaults_non_strict
+      using_strict(false) do
+        with_text_blob_not_null_table do |klass|
+          assert_equal '', klass.columns_hash['non_null_blob'].default
+          assert_equal '', klass.columns_hash['non_null_text'].default
+
+          assert_nil klass.columns_hash['null_blob'].default
+          assert_nil klass.columns_hash['null_text'].default
+
+          instance = klass.create!
+
+          assert_equal '', instance.non_null_text
+          assert_equal '', instance.non_null_blob
+
+          assert_nil instance.null_text
+          assert_nil instance.null_blob
+        end
+      end
+    end
+
+    def test_mysql_text_not_null_defaults_strict
+      using_strict(true) do
+        with_text_blob_not_null_table do |klass|
+          assert_nil klass.columns_hash['non_null_blob'].default
+          assert_nil klass.columns_hash['non_null_text'].default
+          assert_nil klass.columns_hash['null_blob'].default
+          assert_nil klass.columns_hash['null_text'].default
+
+          assert_raises(ActiveRecord::StatementInvalid) { klass.create }
+        end
+      end
+    end
+
+    def with_text_blob_not_null_table
+      klass = Class.new(ActiveRecord::Base)
+      klass.table_name = 'test_mysql_text_not_null_defaults'
+      klass.connection.create_table klass.table_name do |t|
+        t.column :non_null_text, :text, :null => false
+        t.column :non_null_blob, :blob, :null => false
+        t.column :null_text, :text, :null => true
+        t.column :null_blob, :blob, :null => true
+      end
+
+      yield klass
+    ensure
+      klass.connection.drop_table(klass.table_name) rescue nil
+    end
+
+    # MySQL uses an implicit default 0 rather than NULL unless in strict mode.
+    # We use an implicit NULL so schema.rb is compatible with other databases.
+    def test_mysql_integer_not_null_defaults
+      klass = Class.new(ActiveRecord::Base)
+      klass.table_name = 'test_integer_not_null_default_zero'
+      klass.connection.create_table klass.table_name do |t|
+        t.column :zero, :integer, :null => false, :default => 0
+        t.column :omit, :integer, :null => false
+      end
+
+      assert_equal '0', klass.columns_hash['zero'].default
+      assert !klass.columns_hash['zero'].null
+      # 0 in MySQL 4, nil in 5.
+      assert [0, nil].include?(klass.columns_hash['omit'].default)
+      assert !klass.columns_hash['omit'].null
+
+      assert_raise(ActiveRecord::StatementInvalid) { klass.create! }
+
+      assert_nothing_raised do
+        instance = klass.create!(:omit => 1)
+        assert_equal 0, instance.zero
+        assert_equal 1, instance.omit
+      end
+    ensure
+      klass.connection.drop_table(klass.table_name) rescue nil
+    end
+  end
+end
+
+if current_adapter?(:PostgreSQLAdapter)
+  class DefaultsUsingMultipleSchemasAndDomainTest < ActiveSupport::TestCase
+    def setup
+      @connection = ActiveRecord::Base.connection
+
+      @old_search_path = @connection.schema_search_path
+      @connection.schema_search_path = "schema_1, pg_catalog"
+      @connection.create_table "defaults" do |t|
+        t.text "text_col", :default => "some value"
+        t.string "string_col", :default => "some value"
+      end
+      Default.reset_column_information
+    end
+
+    def test_text_defaults_in_new_schema_when_overriding_domain
+      assert_equal "some value", Default.new.text_col, "Default of text column was not correctly parse"
+    end
+
+    def test_string_defaults_in_new_schema_when_overriding_domain
+      assert_equal "some value", Default.new.string_col, "Default of string column was not correctly parse"
+    end
+
+    def test_bpchar_defaults_in_new_schema_when_overriding_domain
+      @connection.execute "ALTER TABLE defaults ADD bpchar_col bpchar DEFAULT 'some value'"
+      Default.reset_column_information
+      assert_equal "some value", Default.new.bpchar_col, "Default of bpchar column was not correctly parse"
+    end
+
+    def test_text_defaults_after_updating_column_default
+      @connection.execute "ALTER TABLE defaults ALTER COLUMN text_col SET DEFAULT 'some text'::schema_1.text"
+      assert_equal "some text", Default.new.text_col, "Default of text column was not correctly parse after updating default using '::text' since postgreSQL will add parens to the default in db"
+    end
+
+    def test_default_containing_quote_and_colons
+      @connection.execute "ALTER TABLE defaults ALTER COLUMN string_col SET DEFAULT 'foo''::bar'"
+      assert_equal "foo'::bar", Default.new.string_col
+    end
+
+    teardown do
+      @connection.schema_search_path = @old_search_path
+      Default.reset_column_information
+    end
+  end
+end
diff --git a/activerecord/test/cases/dirty_test.rb b/activerecord/test/cases/dirty_test.rb
new file mode 100644
index 0000000000..69a7f25213
--- /dev/null
+++ b/activerecord/test/cases/dirty_test.rb
@@ -0,0 +1,679 @@
+require 'cases/helper'
+require 'models/topic'    # For booleans
+require 'models/pirate'   # For timestamps
+require 'models/parrot'
+require 'models/person'   # For optimistic locking
+require 'models/aircraft'
+
+class Pirate # Just reopening it, not defining it
+  attr_accessor :detected_changes_in_after_update # Boolean for if changes are detected
+  attr_accessor :changes_detected_in_after_update # Actual changes
+
+  after_update :check_changes
+
+private
+  # after_save/update and the model itself
+  # can end up checking dirty status and acting on the results
+  def check_changes
+    if self.changed?
+      self.detected_changes_in_after_update = true
+      self.changes_detected_in_after_update = self.changes
+    end
+  end
+end
+
+class NumericData < ActiveRecord::Base
+  self.table_name = 'numeric_data'
+end
+
+class DirtyTest < ActiveRecord::TestCase
+  include InTimeZone
+
+  # Dummy to force column loads so query counts are clean.
+  def setup
+    Person.create :first_name => 'foo'
+  end
+
+  def test_attribute_changes
+    # New record - no changes.
+    pirate = Pirate.new
+    assert !pirate.catchphrase_changed?
+    assert_nil pirate.catchphrase_change
+
+    # Change catchphrase.
+    pirate.catchphrase = 'arrr'
+    assert pirate.catchphrase_changed?
+    assert_nil pirate.catchphrase_was
+    assert_equal [nil, 'arrr'], pirate.catchphrase_change
+
+    # Saved - no changes.
+    pirate.save!
+    assert !pirate.catchphrase_changed?
+    assert_nil pirate.catchphrase_change
+
+    # Same value - no changes.
+    pirate.catchphrase = 'arrr'
+    assert !pirate.catchphrase_changed?
+    assert_nil pirate.catchphrase_change
+  end
+
+  def test_time_attributes_changes_with_time_zone
+    in_time_zone 'Paris' do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = 'pirates'
+
+      # New record - no changes.
+      pirate = target.new
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Saved - no changes.
+      pirate.catchphrase = 'arrrr, time zone!!'
+      pirate.save!
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Change created_on.
+      old_created_on = pirate.created_on
+      pirate.created_on = Time.now - 1.day
+      assert pirate.created_on_changed?
+      assert_kind_of ActiveSupport::TimeWithZone, pirate.created_on_was
+      assert_equal old_created_on, pirate.created_on_was
+      pirate.created_on = old_created_on
+      assert !pirate.created_on_changed?
+    end
+  end
+
+  def test_setting_time_attributes_with_time_zone_field_to_itself_should_not_be_marked_as_a_change
+    in_time_zone 'Paris' do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = 'pirates'
+
+      pirate = target.create
+      pirate.created_on = pirate.created_on
+      assert !pirate.created_on_changed?
+    end
+  end
+
+  def test_time_attributes_changes_without_time_zone_by_skip
+    in_time_zone 'Paris' do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = 'pirates'
+
+      target.skip_time_zone_conversion_for_attributes = [:created_on]
+
+      # New record - no changes.
+      pirate = target.new
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Saved - no changes.
+      pirate.catchphrase = 'arrrr, time zone!!'
+      pirate.save!
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Change created_on.
+      old_created_on = pirate.created_on
+      pirate.created_on = Time.now + 1.day
+      assert pirate.created_on_changed?
+      # kind_of does not work because
+      # ActiveSupport::TimeWithZone.name == 'Time'
+      assert_instance_of Time, pirate.created_on_was
+      assert_equal old_created_on, pirate.created_on_was
+    end
+  end
+
+  def test_time_attributes_changes_without_time_zone
+    with_timezone_config aware_attributes: false do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = 'pirates'
+
+      # New record - no changes.
+      pirate = target.new
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Saved - no changes.
+      pirate.catchphrase = 'arrrr, time zone!!'
+      pirate.save!
+      assert !pirate.created_on_changed?
+      assert_nil pirate.created_on_change
+
+      # Change created_on.
+      old_created_on = pirate.created_on
+      pirate.created_on = Time.now + 1.day
+      assert pirate.created_on_changed?
+      # kind_of does not work because
+      # ActiveSupport::TimeWithZone.name == 'Time'
+      assert_instance_of Time, pirate.created_on_was
+      assert_equal old_created_on, pirate.created_on_was
+    end
+  end
+
+
+  def test_aliased_attribute_changes
+    # the actual attribute here is name, title is an
+    # alias setup via alias_attribute
+    parrot = Parrot.new
+    assert !parrot.title_changed?
+    assert_nil parrot.title_change
+
+    parrot.name = 'Sam'
+    assert parrot.title_changed?
+    assert_nil parrot.title_was
+    assert_equal parrot.name_change, parrot.title_change
+  end
+
+  def test_reset_attribute!
+    pirate = Pirate.create!(:catchphrase => 'Yar!')
+    pirate.catchphrase = 'Ahoy!'
+
+    assert_deprecated do
+      pirate.reset_catchphrase!
+    end
+    assert_equal "Yar!", pirate.catchphrase
+    assert_equal Hash.new, pirate.changes
+    assert !pirate.catchphrase_changed?
+  end
+
+  def test_restore_attribute!
+    pirate = Pirate.create!(:catchphrase => 'Yar!')
+    pirate.catchphrase = 'Ahoy!'
+
+    pirate.restore_catchphrase!
+    assert_equal "Yar!", pirate.catchphrase
+    assert_equal Hash.new, pirate.changes
+    assert !pirate.catchphrase_changed?
+  end
+
+  def test_nullable_number_not_marked_as_changed_if_new_value_is_blank
+    pirate = Pirate.new
+
+    ["", nil].each do |value|
+      pirate.parrot_id = value
+      assert !pirate.parrot_id_changed?
+      assert_nil pirate.parrot_id_change
+    end
+  end
+
+  def test_nullable_decimal_not_marked_as_changed_if_new_value_is_blank
+    numeric_data = NumericData.new
+
+    ["", nil].each do |value|
+      numeric_data.bank_balance = value
+      assert !numeric_data.bank_balance_changed?
+      assert_nil numeric_data.bank_balance_change
+    end
+  end
+
+  def test_nullable_float_not_marked_as_changed_if_new_value_is_blank
+    numeric_data = NumericData.new
+
+    ["", nil].each do |value|
+      numeric_data.temperature = value
+      assert !numeric_data.temperature_changed?
+      assert_nil numeric_data.temperature_change
+    end
+  end
+
+  def test_nullable_datetime_not_marked_as_changed_if_new_value_is_blank
+    in_time_zone 'Edinburgh' do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = 'topics'
+
+      topic = target.create
+      assert_nil topic.written_on
+
+      ["", nil].each do |value|
+        topic.written_on = value
+        assert_nil topic.written_on
+        assert !topic.written_on_changed?
+      end
+    end
+  end
+
+  def test_integer_zero_to_string_zero_not_marked_as_changed
+    pirate = Pirate.new
+    pirate.parrot_id = 0
+    pirate.catchphrase = 'arrr'
+    assert pirate.save!
+
+    assert !pirate.changed?
+
+    pirate.parrot_id = '0'
+    assert !pirate.changed?
+  end
+
+  def test_integer_zero_to_integer_zero_not_marked_as_changed
+    pirate = Pirate.new
+    pirate.parrot_id = 0
+    pirate.catchphrase = 'arrr'
+    assert pirate.save!
+
+    assert !pirate.changed?
+
+    pirate.parrot_id = 0
+    assert !pirate.changed?
+  end
+
+  def test_float_zero_to_string_zero_not_marked_as_changed
+    data = NumericData.new :temperature => 0.0
+    data.save!
+
+    assert_not data.changed?
+
+    data.temperature = '0'
+    assert_empty data.changes
+
+    data.temperature = '0.0'
+    assert_empty data.changes
+
+    data.temperature = '0.00'
+    assert_empty data.changes
+  end
+
+  def test_zero_to_blank_marked_as_changed
+    pirate = Pirate.new
+    pirate.catchphrase = "Yarrrr, me hearties"
+    pirate.parrot_id = 1
+    pirate.save
+
+    # check the change from 1 to ''
+    pirate = Pirate.find_by_catchphrase("Yarrrr, me hearties")
+    pirate.parrot_id = ''
+    assert pirate.parrot_id_changed?
+    assert_equal([1, nil], pirate.parrot_id_change)
+    pirate.save
+
+    # check the change from nil to 0
+    pirate = Pirate.find_by_catchphrase("Yarrrr, me hearties")
+    pirate.parrot_id = 0
+    assert pirate.parrot_id_changed?
+    assert_equal([nil, 0], pirate.parrot_id_change)
+    pirate.save
+
+    # check the change from 0 to ''
+    pirate = Pirate.find_by_catchphrase("Yarrrr, me hearties")
+    pirate.parrot_id = ''
+    assert pirate.parrot_id_changed?
+    assert_equal([0, nil], pirate.parrot_id_change)
+  end
+
+  def test_object_should_be_changed_if_any_attribute_is_changed
+    pirate = Pirate.new
+    assert !pirate.changed?
+    assert_equal [], pirate.changed
+    assert_equal Hash.new, pirate.changes
+
+    pirate.catchphrase = 'arrr'
+    assert pirate.changed?
+    assert_nil pirate.catchphrase_was
+    assert_equal %w(catchphrase), pirate.changed
+    assert_equal({'catchphrase' => [nil, 'arrr']}, pirate.changes)
+
+    pirate.save
+    assert !pirate.changed?
+    assert_equal [], pirate.changed
+    assert_equal Hash.new, pirate.changes
+  end
+
+  def test_attribute_will_change!
+    pirate = Pirate.create!(:catchphrase => 'arr')
+
+    assert !pirate.catchphrase_changed?
+    assert pirate.catchphrase_will_change!
+    assert pirate.catchphrase_changed?
+    assert_equal ['arr', 'arr'], pirate.catchphrase_change
+
+    pirate.catchphrase << ' matey!'
+    assert pirate.catchphrase_changed?
+    assert_equal ['arr', 'arr matey!'], pirate.catchphrase_change
+  end
+
+  def test_association_assignment_changes_foreign_key
+    pirate = Pirate.create!(:catchphrase => 'jarl')
+    pirate.parrot = Parrot.create!(:name => 'Lorre')
+    assert pirate.changed?
+    assert_equal %w(parrot_id), pirate.changed
+  end
+
+  def test_attribute_should_be_compared_with_type_cast
+    topic = Topic.new
+    assert topic.approved?
+    assert !topic.approved_changed?
+
+    # Coming from web form.
+    params = {:topic => {:approved => 1}}
+    # In the controller.
+    topic.attributes = params[:topic]
+    assert topic.approved?
+    assert !topic.approved_changed?
+  end
+
+  def test_partial_update
+    pirate = Pirate.new(:catchphrase => 'foo')
+    old_updated_on = 1.hour.ago.beginning_of_day
+
+    with_partial_writes Pirate, false do
+      assert_queries(2) { 2.times { pirate.save! } }
+      Pirate.where(id: pirate.id).update_all(:updated_on => old_updated_on)
+    end
+
+    with_partial_writes Pirate, true do
+      assert_queries(0) { 2.times { pirate.save! } }
+      assert_equal old_updated_on, pirate.reload.updated_on
+
+      assert_queries(1) { pirate.catchphrase = 'bar'; pirate.save! }
+      assert_not_equal old_updated_on, pirate.reload.updated_on
+    end
+  end
+
+  def test_partial_update_with_optimistic_locking
+    person = Person.new(:first_name => 'foo')
+    old_lock_version = 1
+
+    with_partial_writes Person, false do
+      assert_queries(2) { 2.times { person.save! } }
+      Person.where(id: person.id).update_all(:first_name => 'baz')
+    end
+
+    with_partial_writes Person, true do
+      assert_queries(0) { 2.times { person.save! } }
+      assert_equal old_lock_version, person.reload.lock_version
+
+      assert_queries(1) { person.first_name = 'bar'; person.save! }
+      assert_not_equal old_lock_version, person.reload.lock_version
+    end
+  end
+
+  def test_changed_attributes_should_be_preserved_if_save_failure
+    pirate = Pirate.new
+    pirate.parrot_id = 1
+    assert !pirate.save
+    check_pirate_after_save_failure(pirate)
+
+    pirate = Pirate.new
+    pirate.parrot_id = 1
+    assert_raise(ActiveRecord::RecordInvalid) { pirate.save! }
+    check_pirate_after_save_failure(pirate)
+  end
+
+  def test_reload_should_clear_changed_attributes
+    pirate = Pirate.create!(:catchphrase => "shiver me timbers")
+    pirate.catchphrase = "*hic*"
+    assert pirate.changed?
+    pirate.reload
+    assert !pirate.changed?
+  end
+
+  def test_dup_objects_should_not_copy_dirty_flag_from_creator
+    pirate = Pirate.create!(:catchphrase => "shiver me timbers")
+    pirate_dup = pirate.dup
+    pirate_dup.restore_catchphrase!
+    pirate.catchphrase = "I love Rum"
+    assert pirate.catchphrase_changed?
+    assert !pirate_dup.catchphrase_changed?
+  end
+
+  def test_reverted_changes_are_not_dirty
+    phrase = "shiver me timbers"
+    pirate = Pirate.create!(:catchphrase => phrase)
+    pirate.catchphrase = "*hic*"
+    assert pirate.changed?
+    pirate.catchphrase = phrase
+    assert !pirate.changed?
+  end
+
+  def test_reverted_changes_are_not_dirty_after_multiple_changes
+    phrase = "shiver me timbers"
+    pirate = Pirate.create!(:catchphrase => phrase)
+    10.times do |i|
+      pirate.catchphrase = "*hic*" * i
+      assert pirate.changed?
+    end
+    assert pirate.changed?
+    pirate.catchphrase = phrase
+    assert !pirate.changed?
+  end
+
+
+  def test_reverted_changes_are_not_dirty_going_from_nil_to_value_and_back
+    pirate = Pirate.create!(:catchphrase => "Yar!")
+
+    pirate.parrot_id = 1
+    assert pirate.changed?
+    assert pirate.parrot_id_changed?
+    assert !pirate.catchphrase_changed?
+
+    pirate.parrot_id = nil
+    assert !pirate.changed?
+    assert !pirate.parrot_id_changed?
+    assert !pirate.catchphrase_changed?
+  end
+
+  def test_save_should_store_serialized_attributes_even_with_partial_writes
+    with_partial_writes(Topic) do
+      topic = Topic.create!(:content => {:a => "a"})
+
+      assert_not topic.changed?
+
+      topic.content[:b] = "b"
+
+      assert topic.changed?
+
+      topic.save!
+
+      assert_not topic.changed?
+      assert_equal "b", topic.content[:b]
+
+      topic.reload
+
+      assert_equal "b", topic.content[:b]
+    end
+  end
+
+  def test_save_always_should_update_timestamps_when_serialized_attributes_are_present
+    with_partial_writes(Topic) do
+      topic = Topic.create!(:content => {:a => "a"})
+      topic.save!
+
+      updated_at = topic.updated_at
+      topic.content[:hello] = 'world'
+      topic.save!
+
+      assert_not_equal updated_at, topic.updated_at
+      assert_equal 'world', topic.content[:hello]
+    end
+  end
+
+  def test_save_should_not_save_serialized_attribute_with_partial_writes_if_not_present
+    with_partial_writes(Topic) do
+      Topic.create!(:author_name => 'Bill', :content => {:a => "a"})
+      topic = Topic.select('id, author_name').first
+      topic.update_columns author_name: 'John'
+      topic = Topic.first
+      assert_not_nil topic.content
+    end
+  end
+
+  def test_previous_changes
+    # original values should be in previous_changes
+    pirate = Pirate.new
+
+    assert_equal Hash.new, pirate.previous_changes
+    pirate.catchphrase = "arrr"
+    pirate.save!
+
+    assert_equal 4, pirate.previous_changes.size
+    assert_equal [nil, "arrr"], pirate.previous_changes['catchphrase']
+    assert_equal [nil, pirate.id], pirate.previous_changes['id']
+    assert_nil pirate.previous_changes['updated_on'][0]
+    assert_not_nil pirate.previous_changes['updated_on'][1]
+    assert_nil pirate.previous_changes['created_on'][0]
+    assert_not_nil pirate.previous_changes['created_on'][1]
+    assert !pirate.previous_changes.key?('parrot_id')
+
+    # original values should be in previous_changes
+    pirate = Pirate.new
+
+    assert_equal Hash.new, pirate.previous_changes
+    pirate.catchphrase = "arrr"
+    pirate.save
+
+    assert_equal 4, pirate.previous_changes.size
+    assert_equal [nil, "arrr"], pirate.previous_changes['catchphrase']
+    assert_equal [nil, pirate.id], pirate.previous_changes['id']
+    assert pirate.previous_changes.include?('updated_on')
+    assert pirate.previous_changes.include?('created_on')
+    assert !pirate.previous_changes.key?('parrot_id')
+
+    pirate.catchphrase = "Yar!!"
+    pirate.reload
+    assert_equal Hash.new, pirate.previous_changes
+
+    pirate = Pirate.find_by_catchphrase("arrr")
+    pirate.catchphrase = "Me Maties!"
+    pirate.save!
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["arrr", "Me Maties!"], pirate.previous_changes['catchphrase']
+    assert_not_nil pirate.previous_changes['updated_on'][0]
+    assert_not_nil pirate.previous_changes['updated_on'][1]
+    assert !pirate.previous_changes.key?('parrot_id')
+    assert !pirate.previous_changes.key?('created_on')
+
+    pirate = Pirate.find_by_catchphrase("Me Maties!")
+    pirate.catchphrase = "Thar She Blows!"
+    pirate.save
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["Me Maties!", "Thar She Blows!"], pirate.previous_changes['catchphrase']
+    assert_not_nil pirate.previous_changes['updated_on'][0]
+    assert_not_nil pirate.previous_changes['updated_on'][1]
+    assert !pirate.previous_changes.key?('parrot_id')
+    assert !pirate.previous_changes.key?('created_on')
+
+    pirate = Pirate.find_by_catchphrase("Thar She Blows!")
+    pirate.update(catchphrase: "Ahoy!")
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["Thar She Blows!", "Ahoy!"], pirate.previous_changes['catchphrase']
+    assert_not_nil pirate.previous_changes['updated_on'][0]
+    assert_not_nil pirate.previous_changes['updated_on'][1]
+    assert !pirate.previous_changes.key?('parrot_id')
+    assert !pirate.previous_changes.key?('created_on')
+
+    pirate = Pirate.find_by_catchphrase("Ahoy!")
+    pirate.update_attribute(:catchphrase, "Ninjas suck!")
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["Ahoy!", "Ninjas suck!"], pirate.previous_changes['catchphrase']
+    assert_not_nil pirate.previous_changes['updated_on'][0]
+    assert_not_nil pirate.previous_changes['updated_on'][1]
+    assert !pirate.previous_changes.key?('parrot_id')
+    assert !pirate.previous_changes.key?('created_on')
+  end
+
+  if ActiveRecord::Base.connection.supports_migrations?
+    class Testings < ActiveRecord::Base; end
+    def test_field_named_field
+      ActiveRecord::Base.connection.create_table :testings do |t|
+        t.string :field
+      end
+      assert_nothing_raised do
+        Testings.new.attributes
+      end
+    ensure
+      ActiveRecord::Base.connection.drop_table :testings rescue nil
+    end
+  end
+
+  def test_datetime_attribute_can_be_updated_with_fractional_seconds
+    in_time_zone 'Paris' do
+      target = Class.new(ActiveRecord::Base)
+      target.table_name = 'topics'
+
+      written_on = Time.utc(2012, 12, 1, 12, 0, 0).in_time_zone('Paris')
+
+      topic = target.create(:written_on => written_on)
+      topic.written_on += 0.3
+
+      assert topic.written_on_changed?, 'Fractional second update not detected'
+    end
+  end
+
+  def test_datetime_attribute_doesnt_change_if_zone_is_modified_in_string
+    time_in_paris = Time.utc(2014, 1, 1, 12, 0, 0).in_time_zone('Paris')
+    pirate = Pirate.create!(:catchphrase => 'rrrr', :created_on => time_in_paris)
+
+    pirate.created_on = pirate.created_on.in_time_zone('Tokyo').to_s
+    assert !pirate.created_on_changed?
+  end
+
+  test "partial insert" do
+    with_partial_writes Person do
+      jon = nil
+      assert_sql(/first_name/i) do
+        jon = Person.create! first_name: 'Jon'
+      end
+
+      assert ActiveRecord::SQLCounter.log_all.none? { |sql| sql =~ /followers_count/ }
+
+      jon.reload
+      assert_equal 'Jon', jon.first_name
+      assert_equal 0, jon.followers_count
+      assert_not_nil jon.id
+    end
+  end
+
+  test "partial insert with empty values" do
+    with_partial_writes Aircraft do
+      a = Aircraft.create!
+      a.reload
+      assert_not_nil a.id
+    end
+  end
+
+  test "defaults with type that implements `type_cast_for_database`" do
+    type = Class.new(ActiveRecord::Type::Value) do
+      def type_cast(value)
+        value.to_i
+      end
+
+      def type_cast_for_database(value)
+        value.to_s
+      end
+    end
+
+    model_class = Class.new(ActiveRecord::Base) do
+      self.table_name = 'numeric_data'
+      attribute :foo, type.new, default: 1
+    end
+
+    model = model_class.new
+    assert_not model.foo_changed?
+
+    model = model_class.new(foo: 1)
+    assert_not model.foo_changed?
+
+    model = model_class.new(foo: '1')
+    assert_not model.foo_changed?
+  end
+
+  private
+    def with_partial_writes(klass, on = true)
+      old = klass.partial_writes?
+      klass.partial_writes = on
+      yield
+    ensure
+      klass.partial_writes = old
+    end
+
+    def check_pirate_after_save_failure(pirate)
+      assert pirate.changed?
+      assert pirate.parrot_id_changed?
+      assert_equal %w(parrot_id), pirate.changed
+      assert_nil pirate.parrot_id_was
+    end
+end
diff --git a/activerecord/test/cases/disconnected_test.rb b/activerecord/test/cases/disconnected_test.rb
new file mode 100644
index 0000000000..94447addc1
--- /dev/null
+++ b/activerecord/test/cases/disconnected_test.rb
@@ -0,0 +1,28 @@
+require "cases/helper"
+
+class TestRecord < ActiveRecord::Base
+end
+
+class TestDisconnectedAdapter < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+  end
+
+  teardown do
+    return if in_memory_db?
+    spec = ActiveRecord::Base.connection_config
+    ActiveRecord::Base.establish_connection(spec)
+  end
+
+  unless in_memory_db?
+    test "can't execute statements while disconnected" do
+      @connection.execute "SELECT count(*) from products"
+      @connection.disconnect!
+      assert_raises(ActiveRecord::StatementInvalid) do
+        @connection.execute "SELECT count(*) from products"
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/dup_test.rb b/activerecord/test/cases/dup_test.rb
new file mode 100644
index 0000000000..638cffe0e6
--- /dev/null
+++ b/activerecord/test/cases/dup_test.rb
@@ -0,0 +1,157 @@
+require "cases/helper"
+require 'models/reply'
+require 'models/topic'
+
+module ActiveRecord
+  class DupTest < ActiveRecord::TestCase
+    fixtures :topics
+
+    def test_dup
+      assert !Topic.new.freeze.dup.frozen?
+    end
+
+    def test_not_readonly
+      topic = Topic.first
+
+      duped = topic.dup
+      assert !duped.readonly?, 'should not be readonly'
+    end
+
+    def test_is_readonly
+      topic = Topic.first
+      topic.readonly!
+
+      duped = topic.dup
+      assert duped.readonly?, 'should be readonly'
+    end
+
+    def test_dup_not_persisted
+      topic = Topic.first
+      duped = topic.dup
+
+      assert !duped.persisted?, 'topic not persisted'
+      assert duped.new_record?, 'topic is new'
+    end
+
+    def test_dup_not_destroyed
+      topic = Topic.first
+      topic.destroy
+
+      duped = topic.dup
+      assert_not duped.destroyed?
+    end
+
+    def test_dup_has_no_id
+      topic = Topic.first
+      duped = topic.dup
+      assert_nil duped.id
+    end
+
+    def test_dup_with_modified_attributes
+      topic = Topic.first
+      topic.author_name = 'Aaron'
+      duped = topic.dup
+      assert_equal 'Aaron', duped.author_name
+    end
+
+    def test_dup_with_changes
+      dbtopic = Topic.first
+      topic = Topic.new
+
+      topic.attributes = dbtopic.attributes.except("id")
+
+      #duped has no timestamp values
+      duped = dbtopic.dup
+
+      #clear topic timestamp values
+      topic.send(:clear_timestamp_attributes)
+
+      assert_equal topic.changes, duped.changes
+    end
+
+    def test_dup_topics_are_independent
+      topic = Topic.first
+      topic.author_name = 'Aaron'
+      duped = topic.dup
+
+      duped.author_name = 'meow'
+
+      assert_not_equal topic.changes, duped.changes
+    end
+
+    def test_dup_attributes_are_independent
+      topic = Topic.first
+      duped = topic.dup
+
+      duped.author_name = 'meow'
+      topic.author_name = 'Aaron'
+
+      assert_equal 'Aaron', topic.author_name
+      assert_equal 'meow', duped.author_name
+    end
+
+    def test_dup_timestamps_are_cleared
+      topic = Topic.first
+      assert_not_nil topic.updated_at
+      assert_not_nil topic.created_at
+
+      # temporary change to the topic object
+      topic.updated_at -= 3.days
+
+      #dup should not preserve the timestamps if present
+      new_topic = topic.dup
+      assert_nil new_topic.updated_at
+      assert_nil new_topic.created_at
+
+      new_topic.save
+      assert_not_nil new_topic.updated_at
+      assert_not_nil new_topic.created_at
+    end
+
+    def test_dup_after_initialize_callbacks
+      topic = Topic.new
+      assert Topic.after_initialize_called
+      Topic.after_initialize_called = false
+      topic.dup
+      assert Topic.after_initialize_called
+    end
+
+    def test_dup_validity_is_independent
+      repair_validations(Topic) do
+        Topic.validates_presence_of :title
+        topic = Topic.new("title" => "Literature")
+        topic.valid?
+
+        duped = topic.dup
+        duped.title = nil
+        assert duped.invalid?
+
+        topic.title = nil
+        duped.title = 'Mathematics'
+        assert topic.invalid?
+        assert duped.valid?
+      end
+    end
+
+    def test_dup_with_default_scope
+      prev_default_scopes = Topic.default_scopes
+      Topic.default_scopes = [proc { Topic.where(:approved => true) }]
+      topic = Topic.new(:approved => false)
+      assert !topic.dup.approved?, "should not be overridden by default scopes"
+    ensure
+      Topic.default_scopes = prev_default_scopes
+    end
+
+    def test_dup_without_primary_key
+      klass = Class.new(ActiveRecord::Base) do
+        self.table_name = 'parrots_pirates'
+      end
+
+      record = klass.create!
+
+      assert_nothing_raised do
+        record.dup
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/enum_test.rb b/activerecord/test/cases/enum_test.rb
new file mode 100644
index 0000000000..3b2f0dfe07
--- /dev/null
+++ b/activerecord/test/cases/enum_test.rb
@@ -0,0 +1,289 @@
+require 'cases/helper'
+require 'models/book'
+
+class EnumTest < ActiveRecord::TestCase
+  fixtures :books
+
+  setup do
+    @book = books(:awdr)
+  end
+
+  test "query state by predicate" do
+    assert @book.proposed?
+    assert_not @book.written?
+    assert_not @book.published?
+
+    assert @book.unread?
+  end
+
+  test "query state with strings" do
+    assert_equal "proposed", @book.status
+    assert_equal "unread", @book.read_status
+  end
+
+  test "find via scope" do
+    assert_equal @book, Book.proposed.first
+    assert_equal @book, Book.unread.first
+  end
+
+  test "update by declaration" do
+    @book.written!
+    assert @book.written?
+  end
+
+  test "update by setter" do
+    @book.update! status: :written
+    assert @book.written?
+  end
+
+  test "enum methods are overwritable" do
+    assert_equal "do publish work...", @book.published!
+    assert @book.published?
+  end
+
+  test "direct assignment" do
+    @book.status = :written
+    assert @book.written?
+  end
+
+  test "assign string value" do
+    @book.status = "written"
+    assert @book.written?
+  end
+
+  test "enum changed attributes" do
+    old_status = @book.status
+    @book.status = :published
+    assert_equal old_status, @book.changed_attributes[:status]
+  end
+
+  test "enum changes" do
+    old_status = @book.status
+    @book.status = :published
+    assert_equal [old_status, 'published'], @book.changes[:status]
+  end
+
+  test "enum attribute was" do
+    old_status = @book.status
+    @book.status = :published
+    assert_equal old_status, @book.attribute_was(:status)
+  end
+
+  test "enum attribute changed" do
+    @book.status = :published
+    assert @book.attribute_changed?(:status)
+  end
+
+  test "enum attribute changed to" do
+    @book.status = :published
+    assert @book.attribute_changed?(:status, to: 'published')
+  end
+
+  test "enum attribute changed from" do
+    old_status = @book.status
+    @book.status = :published
+    assert @book.attribute_changed?(:status, from: old_status)
+  end
+
+  test "enum attribute changed from old status to new status" do
+    old_status = @book.status
+    @book.status = :published
+    assert @book.attribute_changed?(:status, from: old_status, to: 'published')
+  end
+
+  test "enum didn't change" do
+    old_status = @book.status
+    @book.status = old_status
+    assert_not @book.attribute_changed?(:status)
+  end
+
+  test "persist changes that are dirty" do
+    @book.status = :published
+    assert @book.attribute_changed?(:status)
+    @book.status = :written
+    assert @book.attribute_changed?(:status)
+  end
+
+  test "reverted changes that are not dirty" do
+    old_status = @book.status
+    @book.status = :published
+    assert @book.attribute_changed?(:status)
+    @book.status = old_status
+    assert_not @book.attribute_changed?(:status)
+  end
+
+  test "reverted changes are not dirty going from nil to value and back" do
+    book = Book.create!(nullable_status: nil)
+
+    book.nullable_status = :married
+    assert book.attribute_changed?(:nullable_status)
+
+    book.nullable_status = nil
+    assert_not book.attribute_changed?(:nullable_status)
+  end
+
+  test "assign non existing value raises an error" do
+    e = assert_raises(ArgumentError) do
+      @book.status = :unknown
+    end
+    assert_equal "'unknown' is not a valid status", e.message
+  end
+
+  test "assign nil value" do
+    @book.status = nil
+    assert @book.status.nil?
+  end
+
+  test "assign empty string value" do
+    @book.status = ''
+    assert @book.status.nil?
+  end
+
+  test "assign long empty string value" do
+    @book.status = '   '
+    assert @book.status.nil?
+  end
+
+  test "constant to access the mapping" do
+    assert_equal 0, Book.statuses[:proposed]
+    assert_equal 1, Book.statuses["written"]
+    assert_equal 2, Book.statuses[:published]
+  end
+
+  test "building new objects with enum scopes" do
+    assert Book.written.build.written?
+    assert Book.read.build.read?
+  end
+
+  test "creating new objects with enum scopes" do
+    assert Book.written.create.written?
+    assert Book.read.create.read?
+  end
+
+  test "_before_type_cast returns the enum label (required for form fields)" do
+    assert_equal "proposed", @book.status_before_type_cast
+  end
+
+  test "reserved enum names" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:proposed, :written, :published]
+    end
+
+    conflicts = [
+      :column,     # generates class method .columns, which conflicts with an AR method
+      :logger,     # generates #logger, which conflicts with an AR method
+      :attributes, # generates #attributes=, which conflicts with an AR method
+    ]
+
+    conflicts.each_with_index do |name, i|
+      assert_raises(ArgumentError, "enum name `#{name}` should not be allowed") do
+        klass.class_eval { enum name => ["value_#{i}"] }
+      end
+    end
+  end
+
+  test "reserved enum values" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:proposed, :written, :published]
+    end
+
+    conflicts = [
+      :new,      # generates a scope that conflicts with an AR class method
+      :valid,    # generates #valid?, which conflicts with an AR method
+      :save,     # generates #save!, which conflicts with an AR method
+      :proposed, # same value as an existing enum
+      :public, :private, :protected, # generates a method that conflict with ruby words
+    ]
+
+    conflicts.each_with_index do |value, i|
+      assert_raises(ArgumentError, "enum value `#{value}` should not be allowed") do
+        klass.class_eval { enum "status_#{i}" => [value] }
+      end
+    end
+  end
+
+  test "overriding enum method should not raise" do
+    assert_nothing_raised do
+      Class.new(ActiveRecord::Base) do
+        self.table_name = "books"
+
+        def published!
+          super
+          "do publish work..."
+        end
+
+        enum status: [:proposed, :written, :published]
+
+        def written!
+          super
+          "do written work..."
+        end
+      end
+    end
+  end
+
+  test "validate uniqueness" do
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Book'; end
+      enum status: [:proposed, :written]
+      validates_uniqueness_of :status
+    end
+    klass.delete_all
+    klass.create!(status: "proposed")
+    book = klass.new(status: "written")
+    assert book.valid?
+    book.status = "proposed"
+    assert_not book.valid?
+  end
+
+  test "validate inclusion of value in array" do
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Book'; end
+      enum status: [:proposed, :written]
+      validates_inclusion_of :status, in: ["written"]
+    end
+    klass.delete_all
+    invalid_book = klass.new(status: "proposed")
+    assert_not invalid_book.valid?
+    valid_book = klass.new(status: "written")
+    assert valid_book.valid?
+  end
+
+  test "enums are distinct per class" do
+    klass1 = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:proposed, :written]
+    end
+
+    klass2 = Class.new(ActiveRecord::Base) do
+      self.table_name = "books"
+      enum status: [:drafted, :uploaded]
+    end
+
+    book1 = klass1.proposed.create!
+    book1.status = :written
+    assert_equal ['proposed', 'written'], book1.status_change
+
+    book2 = klass2.drafted.create!
+    book2.status = :uploaded
+    assert_equal ['drafted', 'uploaded'], book2.status_change
+  end
+
+  test "enums are inheritable" do
+    subklass1 = Class.new(Book)
+
+    subklass2 = Class.new(Book) do
+      enum status: [:drafted, :uploaded]
+    end
+
+    book1 = subklass1.proposed.create!
+    book1.status = :written
+    assert_equal ['proposed', 'written'], book1.status_change
+
+    book2 = subklass2.drafted.create!
+    book2.status = :uploaded
+    assert_equal ['drafted', 'uploaded'], book2.status_change
+  end
+end
diff --git a/activerecord/test/cases/explain_subscriber_test.rb b/activerecord/test/cases/explain_subscriber_test.rb
new file mode 100644
index 0000000000..8de2ddb10d
--- /dev/null
+++ b/activerecord/test/cases/explain_subscriber_test.rb
@@ -0,0 +1,59 @@
+require 'cases/helper'
+require 'active_record/explain_subscriber'
+require 'active_record/explain_registry'
+
+if ActiveRecord::Base.connection.supports_explain?
+  class ExplainSubscriberTest < ActiveRecord::TestCase
+    SUBSCRIBER = ActiveRecord::ExplainSubscriber.new
+
+    def setup
+      ActiveRecord::ExplainRegistry.reset
+      ActiveRecord::ExplainRegistry.collect = true
+    end
+
+    def test_collects_nothing_if_the_payload_has_an_exception
+      SUBSCRIBER.finish(nil, nil, exception: Exception.new)
+      assert queries.empty?
+    end
+
+    def test_collects_nothing_for_ignored_payloads
+      ActiveRecord::ExplainSubscriber::IGNORED_PAYLOADS.each do |ip|
+        SUBSCRIBER.finish(nil, nil, name: ip)
+      end
+      assert queries.empty?
+    end
+
+    def test_collects_nothing_if_collect_is_false
+      ActiveRecord::ExplainRegistry.collect = false
+      SUBSCRIBER.finish(nil, nil, name: 'SQL', sql: 'select 1 from users', binds: [1, 2])
+      assert queries.empty?
+    end
+
+    def test_collects_pairs_of_queries_and_binds
+      sql   = 'select 1 from users'
+      binds = [1, 2]
+      SUBSCRIBER.finish(nil, nil, name: 'SQL', sql: sql, binds: binds)
+      assert_equal 1, queries.size
+      assert_equal sql, queries[0][0]
+      assert_equal binds, queries[0][1]
+    end
+
+    def test_collects_nothing_if_the_statement_is_not_whitelisted
+      SUBSCRIBER.finish(nil, nil, name: 'SQL', sql: 'SHOW max_identifier_length')
+      assert queries.empty?
+    end
+
+    def test_collects_nothing_if_the_statement_is_only_partially_matched
+      SUBSCRIBER.finish(nil, nil, name: 'SQL', sql: 'select_db yo_mama')
+      assert queries.empty?
+    end
+
+    teardown do
+      ActiveRecord::ExplainRegistry.reset
+    end
+
+    def queries
+      ActiveRecord::ExplainRegistry.queries
+    end
+  end
+end
diff --git a/activerecord/test/cases/explain_test.rb b/activerecord/test/cases/explain_test.rb
new file mode 100644
index 0000000000..9d25bdd82a
--- /dev/null
+++ b/activerecord/test/cases/explain_test.rb
@@ -0,0 +1,76 @@
+require 'cases/helper'
+require 'models/car'
+require 'active_support/core_ext/string/strip'
+
+if ActiveRecord::Base.connection.supports_explain?
+  class ExplainTest < ActiveRecord::TestCase
+    fixtures :cars
+
+    def base
+      ActiveRecord::Base
+    end
+
+    def connection
+      base.connection
+    end
+
+    def test_relation_explain
+      message = Car.where(:name => 'honda').explain
+      assert_match(/^EXPLAIN for:/, message)
+    end
+
+    def test_collecting_queries_for_explain
+      queries = ActiveRecord::Base.collecting_queries_for_explain do
+        Car.where(:name => 'honda').to_a
+      end
+
+      sql, binds = queries[0]
+      assert_match "SELECT", sql
+      if binds.any?
+        assert_equal 1, binds.length
+        assert_equal "honda", binds.flatten.last
+      else
+        assert_match 'honda', sql
+      end
+    end
+
+    def test_exec_explain_with_no_binds
+      sqls    = %w(foo bar)
+      binds   = [[], []]
+      queries = sqls.zip(binds)
+
+      connection.stubs(:explain).returns('query plan foo', 'query plan bar')
+      expected = sqls.map {|sql| "EXPLAIN for: #{sql}\nquery plan #{sql}"}.join("\n")
+      assert_equal expected, base.exec_explain(queries)
+    end
+
+    def test_exec_explain_with_binds
+      cols = [Object.new, Object.new]
+      cols[0].expects(:name).returns('wadus')
+      cols[1].expects(:name).returns('chaflan')
+
+      sqls    = %w(foo bar)
+      binds   = [[[cols[0], 1]], [[cols[1], 2]]]
+      queries = sqls.zip(binds)
+
+      connection.stubs(:explain).returns("query plan foo\n", "query plan bar\n")
+      expected = <<-SQL.strip_heredoc
+        EXPLAIN for: #{sqls[0]} [["wadus", 1]]
+        query plan foo
+
+        EXPLAIN for: #{sqls[1]} [["chaflan", 2]]
+        query plan bar
+      SQL
+      assert_equal expected, base.exec_explain(queries)
+    end
+
+    def test_unsupported_connection_adapter
+      connection.stubs(:supports_explain?).returns(false)
+
+      base.logger.expects(:warn).never
+
+      Car.where(:name => 'honda').to_a
+    end
+
+  end
+end
diff --git a/activerecord/test/cases/finder_respond_to_test.rb b/activerecord/test/cases/finder_respond_to_test.rb
new file mode 100644
index 0000000000..6ab2657c44
--- /dev/null
+++ b/activerecord/test/cases/finder_respond_to_test.rb
@@ -0,0 +1,60 @@
+require "cases/helper"
+require 'models/topic'
+
+class FinderRespondToTest < ActiveRecord::TestCase
+
+  fixtures :topics
+
+  def test_should_preserve_normal_respond_to_behaviour_on_base
+    assert_respond_to ActiveRecord::Base, :new
+    assert !ActiveRecord::Base.respond_to?(:find_by_something)
+  end
+
+  def test_should_preserve_normal_respond_to_behaviour_and_respond_to_newly_added_method
+    class << Topic; self; end.send(:define_method, :method_added_for_finder_respond_to_test) { }
+    assert_respond_to Topic, :method_added_for_finder_respond_to_test
+  ensure
+    class << Topic; self; end.send(:remove_method, :method_added_for_finder_respond_to_test)
+  end
+
+  def test_should_preserve_normal_respond_to_behaviour_and_respond_to_standard_object_method
+    assert_respond_to Topic, :to_s
+  end
+
+  def test_should_respond_to_find_by_one_attribute_before_caching
+    ensure_topic_method_is_not_cached(:find_by_title)
+    assert_respond_to Topic, :find_by_title
+  end
+
+  def test_should_respond_to_find_by_with_bang
+    ensure_topic_method_is_not_cached(:find_by_title!)
+    assert_respond_to Topic, :find_by_title!
+  end
+
+  def test_should_respond_to_find_by_two_attributes
+    ensure_topic_method_is_not_cached(:find_by_title_and_author_name)
+    assert_respond_to Topic, :find_by_title_and_author_name
+  end
+
+  def test_should_respond_to_find_all_by_an_aliased_attribute
+    ensure_topic_method_is_not_cached(:find_by_heading)
+    assert_respond_to Topic, :find_by_heading
+  end
+
+  def test_should_not_respond_to_find_by_one_missing_attribute
+    assert !Topic.respond_to?(:find_by_undertitle)
+  end
+
+  def test_should_not_respond_to_find_by_invalid_method_syntax
+    assert !Topic.respond_to?(:fail_to_find_by_title)
+    assert !Topic.respond_to?(:find_by_title?)
+    assert !Topic.respond_to?(:fail_to_find_or_create_by_title)
+    assert !Topic.respond_to?(:find_or_create_by_title?)
+  end
+
+  private
+
+  def ensure_topic_method_is_not_cached(method_id)
+    class << Topic; self; end.send(:remove_method, method_id) if Topic.public_methods.include? method_id
+  end
+end
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
new file mode 100644
index 0000000000..40e51a0cdc
--- /dev/null
+++ b/activerecord/test/cases/finder_test.rb
@@ -0,0 +1,1032 @@
+require "cases/helper"
+require 'models/post'
+require 'models/author'
+require 'models/categorization'
+require 'models/comment'
+require 'models/company'
+require 'models/topic'
+require 'models/reply'
+require 'models/entrant'
+require 'models/project'
+require 'models/developer'
+require 'models/customer'
+require 'models/toy'
+require 'models/matey'
+require 'models/dog'
+
+class FinderTest < ActiveRecord::TestCase
+  fixtures :companies, :topics, :entrants, :developers, :developers_projects, :posts, :comments, :accounts, :authors, :customers, :categories, :categorizations
+
+  def test_find_by_id_with_hash
+    assert_raises(ActiveRecord::StatementInvalid) do
+      Post.find_by_id(:limit => 1)
+    end
+  end
+
+  def test_find_by_title_and_id_with_hash
+    assert_raises(ActiveRecord::StatementInvalid) do
+      Post.find_by_title_and_id('foo', :limit => 1)
+    end
+  end
+
+  def test_find
+    assert_equal(topics(:first).title, Topic.find(1).title)
+  end
+
+  def test_find_with_proc_parameter_and_block
+    exception = assert_raises(RuntimeError) do
+      Topic.all.find(-> { raise "should happen" }) { |e| e.title == "non-existing-title" }
+    end
+    assert_equal "should happen", exception.message
+
+    assert_nothing_raised(RuntimeError) do
+      Topic.all.find(-> { raise "should not happen" }) { |e| e.title == topics(:first).title }
+    end
+  end
+
+  def test_find_passing_active_record_object_is_deprecated
+    assert_deprecated do
+      Topic.find(Topic.last)
+    end
+  end
+
+  def test_symbols_table_ref
+    Post.first # warm up
+    x = Symbol.all_symbols.count
+    Post.where("title" => {"xxxqqqq" => "bar"})
+    assert_equal x, Symbol.all_symbols.count
+  end
+
+  # find should handle strings that come from URLs
+  # (example: Category.find(params[:id]))
+  def test_find_with_string
+    assert_equal(Topic.find(1).title,Topic.find("1").title)
+  end
+
+  def test_exists
+    assert_equal true, Topic.exists?(1)
+    assert_equal true, Topic.exists?("1")
+    assert_equal true, Topic.exists?(title: "The First Topic")
+    assert_equal true, Topic.exists?(heading: "The First Topic")
+    assert_equal true, Topic.exists?(:author_name => "Mary", :approved => true)
+    assert_equal true, Topic.exists?(["parent_id = ?", 1])
+    assert_equal true, Topic.exists?(id: [1, 9999])
+
+    assert_equal false, Topic.exists?(45)
+    assert_equal false, Topic.exists?(Topic.new.id)
+
+    assert_raise(NoMethodError) { Topic.exists?([1,2]) }
+  end
+
+  def test_exists_passing_active_record_object_is_deprecated
+    assert_deprecated do
+      Topic.exists?(Topic.new)
+    end
+  end
+
+  def test_exists_fails_when_parameter_has_invalid_type
+    if current_adapter?(:PostgreSQLAdapter, :MysqlAdapter)
+      assert_raises ActiveRecord::StatementInvalid do
+        Topic.exists?(("9"*53).to_i) # number that's bigger than int
+      end
+    else
+      assert_equal false, Topic.exists?(("9"*53).to_i) # number that's bigger than int
+    end
+
+    if current_adapter?(:PostgreSQLAdapter)
+      assert_raises ActiveRecord::StatementInvalid do
+        Topic.exists?("foo")
+      end
+    else
+      assert_equal false, Topic.exists?("foo")
+    end
+  end
+
+  def test_exists_does_not_select_columns_without_alias
+    assert_sql(/SELECT\W+1 AS one FROM ["`]topics["`]/i) do
+      Topic.exists?
+    end
+  end
+
+  def test_exists_returns_true_with_one_record_and_no_args
+    assert_equal true, Topic.exists?
+  end
+
+  def test_exists_returns_false_with_false_arg
+    assert_equal false, Topic.exists?(false)
+  end
+
+  # exists? should handle nil for id's that come from URLs and always return false
+  # (example: Topic.exists?(params[:id])) where params[:id] is nil
+  def test_exists_with_nil_arg
+    assert_equal false, Topic.exists?(nil)
+    assert_equal true, Topic.exists?
+
+    assert_equal false, Topic.first.replies.exists?(nil)
+    assert_equal true, Topic.first.replies.exists?
+  end
+
+  # ensures +exists?+ runs valid SQL by excluding order value
+  def test_exists_with_order
+    assert_equal true, Topic.order(:id).distinct.exists?
+  end
+
+  def test_exists_with_includes_limit_and_empty_result
+    assert_equal false, Topic.includes(:replies).limit(0).exists?
+    assert_equal false, Topic.includes(:replies).limit(1).where('0 = 1').exists?
+  end
+
+  def test_exists_with_distinct_association_includes_and_limit
+    author = Author.first
+    assert_equal false, author.unique_categorized_posts.includes(:special_comments).limit(0).exists?
+    assert_equal true, author.unique_categorized_posts.includes(:special_comments).limit(1).exists?
+  end
+
+  def test_exists_with_distinct_association_includes_limit_and_order
+    author = Author.first
+    assert_equal false, author.unique_categorized_posts.includes(:special_comments).order('comments.tags_count DESC').limit(0).exists?
+    assert_equal true, author.unique_categorized_posts.includes(:special_comments).order('comments.tags_count DESC').limit(1).exists?
+  end
+
+  def test_exists_with_empty_table_and_no_args_given
+    Topic.delete_all
+    assert_equal false, Topic.exists?
+  end
+
+  def test_exists_with_aggregate_having_three_mappings
+    existing_address = customers(:david).address
+    assert_equal true, Customer.exists?(:address => existing_address)
+  end
+
+  def test_exists_with_aggregate_having_three_mappings_with_one_difference
+    existing_address = customers(:david).address
+    assert_equal false, Customer.exists?(:address =>
+      Address.new(existing_address.street, existing_address.city, existing_address.country + "1"))
+    assert_equal false, Customer.exists?(:address =>
+      Address.new(existing_address.street, existing_address.city + "1", existing_address.country))
+    assert_equal false, Customer.exists?(:address =>
+      Address.new(existing_address.street + "1", existing_address.city, existing_address.country))
+  end
+
+  def test_exists_does_not_instantiate_records
+    Developer.expects(:instantiate).never
+    Developer.exists?
+  end
+
+  def test_find_by_array_of_one_id
+    assert_kind_of(Array, Topic.find([ 1 ]))
+    assert_equal(1, Topic.find([ 1 ]).length)
+  end
+
+  def test_find_by_ids
+    assert_equal 2, Topic.find(1, 2).size
+    assert_equal topics(:second).title, Topic.find([2]).first.title
+  end
+
+  def test_find_by_ids_with_limit_and_offset
+    assert_equal 2, Entrant.limit(2).find([1,3,2]).size
+    assert_equal 1, Entrant.limit(3).offset(2).find([1,3,2]).size
+
+    # Also test an edge case: If you have 11 results, and you set a
+    #   limit of 3 and offset of 9, then you should find that there
+    #   will be only 2 results, regardless of the limit.
+    devs = Developer.all
+    last_devs = Developer.limit(3).offset(9).find devs.map(&:id)
+    assert_equal 2, last_devs.size
+  end
+
+  def test_find_an_empty_array
+    assert_equal [], Topic.find([])
+  end
+
+  def test_find_doesnt_have_implicit_ordering
+    assert_sql(/^((?!ORDER).)*$/) { Topic.find(1) }
+  end
+
+  def test_find_by_ids_missing_one
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(1, 2, 45) }
+  end
+
+  def test_find_with_group_and_sanitized_having_method
+    developers = Developer.group(:salary).having("sum(salary) > ?", 10000).select('salary').to_a
+    assert_equal 3, developers.size
+    assert_equal 3, developers.map(&:salary).uniq.size
+    assert developers.all? { |developer| developer.salary > 10000 }
+  end
+
+  def test_find_with_entire_select_statement
+    topics = Topic.find_by_sql "SELECT * FROM topics WHERE author_name = 'Mary'"
+
+    assert_equal(1, topics.size)
+    assert_equal(topics(:second).title, topics.first.title)
+  end
+
+  def test_find_with_prepared_select_statement
+    topics = Topic.find_by_sql ["SELECT * FROM topics WHERE author_name = ?", "Mary"]
+
+    assert_equal(1, topics.size)
+    assert_equal(topics(:second).title, topics.first.title)
+  end
+
+  def test_find_by_sql_with_sti_on_joined_table
+    accounts = Account.find_by_sql("SELECT * FROM accounts INNER JOIN companies ON companies.id = accounts.firm_id")
+    assert_equal [Account], accounts.collect(&:class).uniq
+  end
+
+  def test_take
+    assert_equal topics(:first), Topic.take
+  end
+
+  def test_take_failing
+    assert_nil Topic.where("title = 'This title does not exist'").take
+  end
+
+  def test_take_bang_present
+    assert_nothing_raised do
+      assert_equal topics(:second), Topic.where("title = 'The Second Topic of the day'").take!
+    end
+  end
+
+  def test_take_bang_missing
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.where("title = 'This title does not exist'").take!
+    end
+  end
+
+  def test_first
+    assert_equal topics(:second).title, Topic.where("title = 'The Second Topic of the day'").first.title
+  end
+
+  def test_first_failing
+    assert_nil Topic.where("title = 'The Second Topic of the day!'").first
+  end
+
+  def test_first_bang_present
+    assert_nothing_raised do
+      assert_equal topics(:second), Topic.where("title = 'The Second Topic of the day'").first!
+    end
+  end
+
+  def test_first_bang_missing
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.where("title = 'This title does not exist'").first!
+    end
+  end
+
+  def test_first_have_primary_key_order_by_default
+    expected = topics(:first)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.first
+  end
+
+  def test_model_class_responds_to_first_bang
+    assert Topic.first!
+    Topic.delete_all
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.first!
+    end
+  end
+
+  def test_second
+    assert_equal topics(:second).title, Topic.second.title
+  end
+
+  def test_second_with_offset
+    assert_equal topics(:fifth), Topic.offset(3).second
+  end
+
+  def test_second_have_primary_key_order_by_default
+    expected = topics(:second)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.second
+  end
+
+  def test_model_class_responds_to_second_bang
+    assert Topic.second!
+    Topic.delete_all
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.second!
+    end
+  end
+
+  def test_third
+    assert_equal topics(:third).title, Topic.third.title
+  end
+
+  def test_third_with_offset
+    assert_equal topics(:fifth), Topic.offset(2).third
+  end
+
+  def test_third_have_primary_key_order_by_default
+    expected = topics(:third)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.third
+  end
+
+  def test_model_class_responds_to_third_bang
+    assert Topic.third!
+    Topic.delete_all
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.third!
+    end
+  end
+
+  def test_fourth
+    assert_equal topics(:fourth).title, Topic.fourth.title
+  end
+
+  def test_fourth_with_offset
+    assert_equal topics(:fifth), Topic.offset(1).fourth
+  end
+
+  def test_fourth_have_primary_key_order_by_default
+    expected = topics(:fourth)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.fourth
+  end
+
+  def test_model_class_responds_to_fourth_bang
+    assert Topic.fourth!
+    Topic.delete_all
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.fourth!
+    end
+  end
+
+  def test_fifth
+    assert_equal topics(:fifth).title, Topic.fifth.title
+  end
+
+  def test_fifth_with_offset
+    assert_equal topics(:fifth), Topic.offset(0).fifth
+  end
+
+  def test_fifth_have_primary_key_order_by_default
+    expected = topics(:fifth)
+    expected.touch # PostgreSQL changes the default order if no order clause is used
+    assert_equal expected, Topic.fifth
+  end
+
+  def test_model_class_responds_to_fifth_bang
+    assert Topic.fifth!
+    Topic.delete_all
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.fifth!
+    end
+  end
+
+  def test_last_bang_present
+    assert_nothing_raised do
+      assert_equal topics(:second), Topic.where("title = 'The Second Topic of the day'").last!
+    end
+  end
+
+  def test_last_bang_missing
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.where("title = 'This title does not exist'").last!
+    end
+  end
+
+  def test_model_class_responds_to_last_bang
+    assert_equal topics(:fifth), Topic.last!
+    assert_raises ActiveRecord::RecordNotFound do
+      Topic.delete_all
+      Topic.last!
+    end
+  end
+
+  def test_take_and_first_and_last_with_integer_should_use_sql_limit
+    assert_sql(/LIMIT 3|ROWNUM <= 3/) { Topic.take(3).entries }
+    assert_sql(/LIMIT 2|ROWNUM <= 2/) { Topic.first(2).entries }
+    assert_sql(/LIMIT 5|ROWNUM <= 5/) { Topic.last(5).entries }
+  end
+
+  def test_last_with_integer_and_order_should_keep_the_order
+    assert_equal Topic.order("title").to_a.last(2), Topic.order("title").last(2)
+  end
+
+  def test_last_with_integer_and_order_should_not_use_sql_limit
+    query = assert_sql { Topic.order("title").last(5).entries }
+    assert_equal 1, query.length
+    assert_no_match(/LIMIT/, query.first)
+  end
+
+  def test_last_with_integer_and_reorder_should_not_use_sql_limit
+    query = assert_sql { Topic.reorder("title").last(5).entries }
+    assert_equal 1, query.length
+    assert_no_match(/LIMIT/, query.first)
+  end
+
+  def test_take_and_first_and_last_with_integer_should_return_an_array
+    assert_kind_of Array, Topic.take(5)
+    assert_kind_of Array, Topic.first(5)
+    assert_kind_of Array, Topic.last(5)
+  end
+
+  def test_unexisting_record_exception_handling
+    assert_raise(ActiveRecord::RecordNotFound) {
+      Topic.find(1).parent
+    }
+
+    Topic.find(2).topic
+  end
+
+  def test_find_only_some_columns
+    topic = Topic.select("author_name").find(1)
+    assert_raise(ActiveModel::MissingAttributeError) {topic.title}
+    assert_raise(ActiveModel::MissingAttributeError) {topic.title?}
+    assert_nil topic.read_attribute("title")
+    assert_equal "David", topic.author_name
+    assert !topic.attribute_present?("title")
+    assert !topic.attribute_present?(:title)
+    assert topic.attribute_present?("author_name")
+    assert_respond_to topic, "author_name"
+  end
+
+  def test_find_on_array_conditions
+    assert Topic.where(["approved = ?", false]).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(["approved = ?", true]).find(1) }
+  end
+
+  def test_find_on_hash_conditions
+    assert Topic.where(approved: false).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(approved: true).find(1) }
+  end
+
+  def test_find_on_hash_conditions_with_explicit_table_name
+    assert Topic.where('topics.approved' => false).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where('topics.approved' => true).find(1) }
+  end
+
+  def test_find_on_hash_conditions_with_hashed_table_name
+    assert Topic.where(topics: { approved: false }).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(topics: { approved: true }).find(1) }
+  end
+
+  def test_find_with_hash_conditions_on_joined_table
+    firms = Firm.joins(:account).where(:accounts => { :credit_limit => 50 })
+    assert_equal 1, firms.size
+    assert_equal companies(:first_firm), firms.first
+  end
+
+  def test_find_with_hash_conditions_on_joined_table_and_with_range
+    firms = DependentFirm.joins(:account).where(name: 'RailsCore', accounts: { credit_limit: 55..60 })
+    assert_equal 1, firms.size
+    assert_equal companies(:rails_core), firms.first
+  end
+
+  def test_find_on_hash_conditions_with_explicit_table_name_and_aggregate
+    david = customers(:david)
+    assert Customer.where('customers.name' => david.name, :address => david.address).find(david.id)
+    assert_raise(ActiveRecord::RecordNotFound) {
+      Customer.where('customers.name' => david.name + "1", :address => david.address).find(david.id)
+    }
+  end
+
+  def test_find_on_association_proxy_conditions
+    assert_equal [1, 2, 3, 5, 6, 7, 8, 9, 10, 12], Comment.where(post_id: authors(:david).posts).map(&:id).sort
+  end
+
+  def test_find_on_hash_conditions_with_range
+    assert_equal [1,2], Topic.where(id: 1..2).to_a.map(&:id).sort
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(id: 2..3).find(1) }
+  end
+
+  def test_find_on_hash_conditions_with_end_exclusive_range
+    assert_equal [1,2,3], Topic.where(id: 1..3).to_a.map(&:id).sort
+    assert_equal [1,2], Topic.where(id: 1...3).to_a.map(&:id).sort
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(id: 2...3).find(3) }
+  end
+
+  def test_find_on_hash_conditions_with_multiple_ranges
+    assert_equal [1,2,3], Comment.where(id: 1..3, post_id: 1..2).to_a.map(&:id).sort
+    assert_equal [1], Comment.where(id: 1..1, post_id: 1..10).to_a.map(&:id).sort
+  end
+
+  def test_find_on_hash_conditions_with_array_of_integers_and_ranges
+    assert_equal [1,2,3,5,6,7,8,9], Comment.where(id: [1..2, 3, 5, 6..8, 9]).to_a.map(&:id).sort
+  end
+
+  def test_find_on_multiple_hash_conditions
+    assert Topic.where(author_name: "David", title: "The First Topic", replies_count: 1, approved: false).find(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(author_name: "David", title: "The First Topic", replies_count: 1, approved: true).find(1) }
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(author_name: "David", title: "HHC", replies_count: 1, approved: false).find(1) }
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.where(author_name: "David", title: "The First Topic", replies_count: 1, approved: true).find(1) }
+  end
+
+  def test_condition_interpolation
+    assert_kind_of Firm, Company.where("name = '%s'", "37signals").first
+    assert_nil Company.where(["name = '%s'", "37signals!"]).first
+    assert_nil Company.where(["name = '%s'", "37signals!' OR 1=1"]).first
+    assert_kind_of Time, Topic.where(["id = %d", 1]).first.written_on
+  end
+
+  def test_condition_array_interpolation
+    assert_kind_of Firm, Company.where(["name = '%s'", "37signals"]).first
+    assert_nil Company.where(["name = '%s'", "37signals!"]).first
+    assert_nil Company.where(["name = '%s'", "37signals!' OR 1=1"]).first
+    assert_kind_of Time, Topic.where(["id = %d", 1]).first.written_on
+  end
+
+  def test_condition_hash_interpolation
+    assert_kind_of Firm, Company.where(name: "37signals").first
+    assert_nil Company.where(name: "37signals!").first
+    assert_kind_of Time, Topic.where(id: 1).first.written_on
+  end
+
+  def test_hash_condition_find_malformed
+    assert_raise(ActiveRecord::StatementInvalid) {
+      Company.where(id: 2, dhh: true).first
+    }
+  end
+
+  def test_hash_condition_find_with_escaped_characters
+    Company.create("name" => "Ain't noth'n like' \#stuff")
+    assert Company.where(name: "Ain't noth'n like' \#stuff").first
+  end
+
+  def test_hash_condition_find_with_array
+    p1, p2 = Post.limit(2).order('id asc').to_a
+    assert_equal [p1, p2], Post.where(id: [p1, p2]).order('id asc').to_a
+    assert_equal [p1, p2], Post.where(id: [p1, p2.id]).order('id asc').to_a
+  end
+
+  def test_hash_condition_find_with_nil
+    topic = Topic.where(last_read: nil).first
+    assert_not_nil topic
+    assert_nil topic.last_read
+  end
+
+  def test_hash_condition_find_with_aggregate_having_one_mapping
+    balance = customers(:david).balance
+    assert_kind_of Money, balance
+    found_customer = Customer.where(:balance => balance).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_aggregate_attribute_having_same_name_as_field_and_key_value_being_aggregate
+    gps_location = customers(:david).gps_location
+    assert_kind_of GpsLocation, gps_location
+    found_customer = Customer.where(:gps_location => gps_location).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_aggregate_having_one_mapping_and_key_value_being_attribute_value
+    balance = customers(:david).balance
+    assert_kind_of Money, balance
+    found_customer = Customer.where(:balance => balance.amount).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_aggregate_attribute_having_same_name_as_field_and_key_value_being_attribute_value
+    gps_location = customers(:david).gps_location
+    assert_kind_of GpsLocation, gps_location
+    found_customer = Customer.where(:gps_location => gps_location.gps_location).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_aggregate_having_three_mappings
+    address = customers(:david).address
+    assert_kind_of Address, address
+    found_customer = Customer.where(:address => address).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_hash_condition_find_with_one_condition_being_aggregate_and_another_not
+    address = customers(:david).address
+    assert_kind_of Address, address
+    found_customer = Customer.where(:address => address, :name => customers(:david).name).first
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_condition_utc_time_interpolation_with_default_timezone_local
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :local do
+        topic = Topic.first
+        assert_equal topic, Topic.where(['written_on = ?', topic.written_on.getutc]).first
+      end
+    end
+  end
+
+  def test_hash_condition_utc_time_interpolation_with_default_timezone_local
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :local do
+        topic = Topic.first
+        assert_equal topic, Topic.where(written_on: topic.written_on.getutc).first
+      end
+    end
+  end
+
+  def test_condition_local_time_interpolation_with_default_timezone_utc
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :utc do
+        topic = Topic.first
+        assert_equal topic, Topic.where(['written_on = ?', topic.written_on.getlocal]).first
+      end
+    end
+  end
+
+  def test_hash_condition_local_time_interpolation_with_default_timezone_utc
+    with_env_tz 'America/New_York' do
+      with_timezone_config default: :utc do
+        topic = Topic.first
+        assert_equal topic, Topic.where(written_on: topic.written_on.getlocal).first
+      end
+    end
+  end
+
+  def test_bind_variables
+    assert_kind_of Firm, Company.where(["name = ?", "37signals"]).first
+    assert_nil Company.where(["name = ?", "37signals!"]).first
+    assert_nil Company.where(["name = ?", "37signals!' OR 1=1"]).first
+    assert_kind_of Time, Topic.where(["id = ?", 1]).first.written_on
+    assert_raise(ActiveRecord::PreparedStatementInvalid) {
+      Company.where(["id=? AND name = ?", 2]).first
+    }
+    assert_raise(ActiveRecord::PreparedStatementInvalid) {
+     Company.where(["id=?", 2, 3, 4]).first
+    }
+  end
+
+  def test_bind_variables_with_quotes
+    Company.create("name" => "37signals' go'es agains")
+    assert Company.where(["name = ?", "37signals' go'es agains"]).first
+  end
+
+  def test_named_bind_variables_with_quotes
+    Company.create("name" => "37signals' go'es agains")
+    assert Company.where(["name = :name", {name: "37signals' go'es agains"}]).first
+  end
+
+  def test_bind_arity
+    assert_nothing_raised                                 { bind '' }
+    assert_raise(ActiveRecord::PreparedStatementInvalid) { bind '', 1 }
+
+    assert_raise(ActiveRecord::PreparedStatementInvalid) { bind '?' }
+    assert_nothing_raised                                 { bind '?', 1 }
+    assert_raise(ActiveRecord::PreparedStatementInvalid) { bind '?', 1, 1  }
+  end
+
+  def test_named_bind_variables
+    assert_equal '1', bind(':a', :a => 1) # ' ruby-mode
+    assert_equal '1 1', bind(':a :a', :a => 1)  # ' ruby-mode
+
+    assert_nothing_raised { bind("'+00:00'", :foo => "bar") }
+
+    assert_kind_of Firm, Company.where(["name = :name", { name: "37signals" }]).first
+    assert_nil Company.where(["name = :name", { name: "37signals!" }]).first
+    assert_nil Company.where(["name = :name", { name: "37signals!' OR 1=1" }]).first
+    assert_kind_of Time, Topic.where(["id = :id", { id: 1 }]).first.written_on
+  end
+
+  class SimpleEnumerable
+    include Enumerable
+
+    def initialize(ary)
+      @ary = ary
+    end
+
+    def each(&b)
+      @ary.each(&b)
+    end
+  end
+
+  def test_bind_enumerable
+    quoted_abc = %(#{ActiveRecord::Base.connection.quote('a')},#{ActiveRecord::Base.connection.quote('b')},#{ActiveRecord::Base.connection.quote('c')})
+
+    assert_equal '1,2,3', bind('?', [1, 2, 3])
+    assert_equal quoted_abc, bind('?', %w(a b c))
+
+    assert_equal '1,2,3', bind(':a', :a => [1, 2, 3])
+    assert_equal quoted_abc, bind(':a', :a => %w(a b c)) # '
+
+    assert_equal '1,2,3', bind('?', SimpleEnumerable.new([1, 2, 3]))
+    assert_equal quoted_abc, bind('?', SimpleEnumerable.new(%w(a b c)))
+
+    assert_equal '1,2,3', bind(':a', :a => SimpleEnumerable.new([1, 2, 3]))
+    assert_equal quoted_abc, bind(':a', :a => SimpleEnumerable.new(%w(a b c))) # '
+  end
+
+  def test_bind_empty_enumerable
+    quoted_nil = ActiveRecord::Base.connection.quote(nil)
+    assert_equal quoted_nil, bind('?', [])
+    assert_equal " in (#{quoted_nil})", bind(' in (?)', [])
+    assert_equal "foo in (#{quoted_nil})", bind('foo in (?)', [])
+  end
+
+  def test_bind_empty_string
+    quoted_empty = ActiveRecord::Base.connection.quote('')
+    assert_equal quoted_empty, bind('?', '')
+  end
+
+  def test_bind_chars
+    quoted_bambi = ActiveRecord::Base.connection.quote("Bambi")
+    quoted_bambi_and_thumper = ActiveRecord::Base.connection.quote("Bambi\nand\nThumper")
+    assert_equal "name=#{quoted_bambi}", bind('name=?', "Bambi")
+    assert_equal "name=#{quoted_bambi_and_thumper}", bind('name=?', "Bambi\nand\nThumper")
+    assert_equal "name=#{quoted_bambi}", bind('name=?', "Bambi".mb_chars)
+    assert_equal "name=#{quoted_bambi_and_thumper}", bind('name=?', "Bambi\nand\nThumper".mb_chars)
+  end
+
+  def test_bind_record
+    o = Struct.new(:quoted_id).new(1)
+    assert_equal '1', bind('?', o)
+
+    os = [o] * 3
+    assert_equal '1,1,1', bind('?', os)
+  end
+
+  def test_named_bind_with_postgresql_type_casts
+    l = Proc.new { bind(":a::integer '2009-01-01'::date", :a => '10') }
+    assert_nothing_raised(&l)
+    assert_equal "#{ActiveRecord::Base.connection.quote('10')}::integer '2009-01-01'::date", l.call
+  end
+
+  def test_string_sanitation
+    assert_not_equal "'something ' 1=1'", ActiveRecord::Base.sanitize("something ' 1=1")
+    assert_equal "'something; select table'", ActiveRecord::Base.sanitize("something; select table")
+  end
+
+  def test_count_by_sql
+    assert_equal(0, Entrant.count_by_sql("SELECT COUNT(*) FROM entrants WHERE id > 3"))
+    assert_equal(1, Entrant.count_by_sql(["SELECT COUNT(*) FROM entrants WHERE id > ?", 2]))
+    assert_equal(2, Entrant.count_by_sql(["SELECT COUNT(*) FROM entrants WHERE id > ?", 1]))
+  end
+
+  def test_find_by_one_attribute
+    assert_equal topics(:first), Topic.find_by_title("The First Topic")
+    assert_nil Topic.find_by_title("The First Topic!")
+  end
+
+  def test_find_by_one_attribute_bang
+    assert_equal topics(:first), Topic.find_by_title!("The First Topic")
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find_by_title!("The First Topic!") }
+  end
+
+  def test_find_by_on_attribute_that_is_a_reserved_word
+    dog_alias = 'Dog'
+    dog = Dog.create(alias: dog_alias)
+
+    assert_equal dog, Dog.find_by_alias(dog_alias)
+  end
+
+  def test_find_by_one_attribute_that_is_an_alias
+    assert_equal topics(:first), Topic.find_by_heading("The First Topic")
+    assert_nil Topic.find_by_heading("The First Topic!")
+  end
+
+  def test_find_by_one_attribute_bang_with_blank_defined
+    blank_topic = BlankTopic.create(title: "The Blank One")
+    assert_equal blank_topic, BlankTopic.find_by_title!("The Blank One")
+  end
+
+  def test_find_by_one_attribute_with_conditions
+    assert_equal accounts(:rails_core_account), Account.where('firm_id = ?', 6).find_by_credit_limit(50)
+  end
+
+  def test_find_by_one_attribute_that_is_an_aggregate
+    address = customers(:david).address
+    assert_kind_of Address, address
+    found_customer = Customer.find_by_address(address)
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_find_by_one_attribute_that_is_an_aggregate_with_one_attribute_difference
+    address = customers(:david).address
+    assert_kind_of Address, address
+    missing_address = Address.new(address.street, address.city, address.country + "1")
+    assert_nil Customer.find_by_address(missing_address)
+    missing_address = Address.new(address.street, address.city + "1", address.country)
+    assert_nil Customer.find_by_address(missing_address)
+    missing_address = Address.new(address.street + "1", address.city, address.country)
+    assert_nil Customer.find_by_address(missing_address)
+  end
+
+  def test_find_by_two_attributes_that_are_both_aggregates
+    balance = customers(:david).balance
+    address = customers(:david).address
+    assert_kind_of Money, balance
+    assert_kind_of Address, address
+    found_customer = Customer.find_by_balance_and_address(balance, address)
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_find_by_two_attributes_with_one_being_an_aggregate
+    balance = customers(:david).balance
+    assert_kind_of Money, balance
+    found_customer = Customer.find_by_balance_and_name(balance, customers(:david).name)
+    assert_equal customers(:david), found_customer
+  end
+
+  def test_dynamic_finder_on_one_attribute_with_conditions_returns_same_results_after_caching
+    # ensure this test can run independently of order
+    class << Account; self; end.send(:remove_method, :find_by_credit_limit) if Account.public_methods.include?(:find_by_credit_limit)
+    a = Account.where('firm_id = ?', 6).find_by_credit_limit(50)
+    assert_equal a, Account.where('firm_id = ?', 6).find_by_credit_limit(50) # find_by_credit_limit has been cached
+  end
+
+  def test_find_by_one_attribute_with_several_options
+    assert_equal accounts(:unknown), Account.order('id DESC').where('id != ?', 3).find_by_credit_limit(50)
+  end
+
+  def test_find_by_one_missing_attribute
+    assert_raise(NoMethodError) { Topic.find_by_undertitle("The First Topic!") }
+  end
+
+  def test_find_by_invalid_method_syntax
+    assert_raise(NoMethodError) { Topic.fail_to_find_by_title("The First Topic") }
+    assert_raise(NoMethodError) { Topic.find_by_title?("The First Topic") }
+    assert_raise(NoMethodError) { Topic.fail_to_find_or_create_by_title("Nonexistent Title") }
+    assert_raise(NoMethodError) { Topic.find_or_create_by_title?("Nonexistent Title") }
+  end
+
+  def test_find_by_two_attributes
+    assert_equal topics(:first), Topic.find_by_title_and_author_name("The First Topic", "David")
+    assert_nil Topic.find_by_title_and_author_name("The First Topic", "Mary")
+  end
+
+  def test_find_by_two_attributes_but_passing_only_one
+    assert_raise(ArgumentError) { Topic.find_by_title_and_author_name("The First Topic") }
+  end
+
+  def test_find_last_with_offset
+    devs = Developer.order('id')
+
+    assert_equal devs[2], Developer.offset(2).first
+    assert_equal devs[-3], Developer.offset(2).last
+    assert_equal devs[-3], Developer.offset(2).last
+    assert_equal devs[-3], Developer.offset(2).order('id DESC').first
+  end
+
+  def test_find_by_nil_attribute
+    topic = Topic.find_by_last_read nil
+    assert_not_nil topic
+    assert_nil topic.last_read
+  end
+
+  def test_find_by_nil_and_not_nil_attributes
+    topic = Topic.find_by_last_read_and_author_name nil, "Mary"
+    assert_equal "Mary", topic.author_name
+  end
+
+  def test_find_with_bad_sql
+    assert_raise(ActiveRecord::StatementInvalid) { Topic.find_by_sql "select 1 from badtable" }
+  end
+
+  def test_find_all_with_join
+    developers_on_project_one = Developer.
+      joins('LEFT JOIN developers_projects ON developers.id = developers_projects.developer_id').
+      where('project_id=1').to_a
+    assert_equal 3, developers_on_project_one.length
+    developer_names = developers_on_project_one.map { |d| d.name }
+    assert developer_names.include?('David')
+    assert developer_names.include?('Jamis')
+  end
+
+  def test_joins_dont_clobber_id
+    first = Firm.
+      joins('INNER JOIN companies clients ON clients.firm_id = companies.id').
+      where('companies.id = 1').first
+    assert_equal 1, first.id
+  end
+
+  def test_joins_with_string_array
+    person_with_reader_and_post = Post.
+      joins(["INNER JOIN categorizations ON categorizations.post_id = posts.id",
+             "INNER JOIN categories ON categories.id = categorizations.category_id AND categories.type = 'SpecialCategory'"
+            ])
+    assert_equal 1, person_with_reader_and_post.size
+  end
+
+  def test_find_by_id_with_conditions_with_or
+    assert_nothing_raised do
+      Post.where("posts.id <= 3 OR posts.#{QUOTED_TYPE} = 'Post'").find([1,2,3])
+    end
+  end
+
+  # http://dev.rubyonrails.org/ticket/6778
+  def test_find_ignores_previously_inserted_record
+    Post.create!(:title => 'test', :body => 'it out')
+    assert_equal [], Post.where(id: nil)
+  end
+
+  def test_find_by_empty_ids
+    assert_equal [], Post.find([])
+  end
+
+  def test_find_by_empty_in_condition
+    assert_equal [], Post.where('id in (?)', [])
+  end
+
+  def test_find_by_records
+    p1, p2 = Post.limit(2).order('id asc').to_a
+    assert_equal [p1, p2], Post.where(['id in (?)', [p1, p2]]).order('id asc')
+    assert_equal [p1, p2], Post.where(['id in (?)', [p1, p2.id]]).order('id asc')
+  end
+
+  def test_select_value
+    assert_equal "37signals", Company.connection.select_value("SELECT name FROM companies WHERE id = 1")
+    assert_nil Company.connection.select_value("SELECT name FROM companies WHERE id = -1")
+    # make sure we didn't break count...
+    assert_equal 0, Company.count_by_sql("SELECT COUNT(*) FROM companies WHERE name = 'Halliburton'")
+    assert_equal 1, Company.count_by_sql("SELECT COUNT(*) FROM companies WHERE name = '37signals'")
+  end
+
+  def test_select_values
+    assert_equal ["1","2","3","4","5","6","7","8","9", "10", "11"], Company.connection.select_values("SELECT id FROM companies ORDER BY id").map! { |i| i.to_s }
+    assert_equal ["37signals","Summit","Microsoft", "Flamboyant Software", "Ex Nihilo", "RailsCore", "Leetsoft", "Jadedpixel", "Odegy", "Ex Nihilo Part Deux", "Apex"], Company.connection.select_values("SELECT name FROM companies ORDER BY id")
+  end
+
+  def test_select_rows
+    assert_equal(
+      [["1", "1", nil, "37signals"],
+       ["2", "1", "2", "Summit"],
+       ["3", "1", "1", "Microsoft"]],
+      Company.connection.select_rows("SELECT id, firm_id, client_of, name FROM companies WHERE id IN (1,2,3) ORDER BY id").map! {|i| i.map! {|j| j.to_s unless j.nil?}})
+    assert_equal [["1", "37signals"], ["2", "Summit"], ["3", "Microsoft"]],
+      Company.connection.select_rows("SELECT id, name FROM companies WHERE id IN (1,2,3) ORDER BY id").map! {|i| i.map! {|j| j.to_s unless j.nil?}}
+  end
+
+  def test_find_with_order_on_included_associations_with_construct_finder_sql_for_association_limiting_and_is_distinct
+    assert_equal 2, Post.includes(authors: :author_address).order('author_addresses.id DESC ').limit(2).to_a.size
+
+    assert_equal 3, Post.includes(author: :author_address, authors: :author_address).
+                              order('author_addresses_authors.id DESC ').limit(3).to_a.size
+  end
+
+  def test_find_with_nil_inside_set_passed_for_one_attribute
+    client_of = Company.
+      where(client_of: [2, 1, nil],
+            name: ['37signals', 'Summit', 'Microsoft']).
+      order('client_of DESC').
+      map { |x| x.client_of }
+
+    assert client_of.include?(nil)
+    assert_equal [2, 1].sort, client_of.compact.sort
+  end
+
+  def test_find_with_nil_inside_set_passed_for_attribute
+    client_of = Company.
+      where(client_of: [nil]).
+      order('client_of DESC').
+      map { |x| x.client_of }
+
+    assert_equal [], client_of.compact
+  end
+
+  def test_with_limiting_with_custom_select
+    posts = Post.references(:authors).merge(
+      :includes => :author, :select => 'posts.*, authors.id as "author_id"',
+      :limit => 3, :order => 'posts.id'
+    ).to_a
+    assert_equal 3, posts.size
+    assert_equal [0, 1, 1], posts.map(&:author_id).sort
+  end
+
+  def test_find_one_message_with_custom_primary_key
+    table_with_custom_primary_key do |model|
+      model.primary_key = :name
+      e = assert_raises(ActiveRecord::RecordNotFound) do
+        model.find 'Hello World!'
+      end
+      assert_equal %Q{Couldn't find MercedesCar with 'name'=Hello World!}, e.message
+    end
+  end
+
+  def test_find_some_message_with_custom_primary_key
+    table_with_custom_primary_key do |model|
+      model.primary_key = :name
+      e = assert_raises(ActiveRecord::RecordNotFound) do
+        model.find 'Hello', 'World!'
+      end
+      assert_equal %Q{Couldn't find all MercedesCars with 'name': (Hello, World!) (found 0 results, but was looking for 2)}, e.message
+    end
+  end
+
+  def test_find_without_primary_key
+    assert_raises(ActiveRecord::UnknownPrimaryKey) do
+      Matey.find(1)
+    end
+  end
+
+  def test_finder_with_offset_string
+    assert_nothing_raised(ActiveRecord::StatementInvalid) { Topic.offset("3").to_a }
+  end
+
+  protected
+    def bind(statement, *vars)
+      if vars.first.is_a?(Hash)
+        ActiveRecord::Base.send(:replace_named_bind_variables, statement, vars.first)
+      else
+        ActiveRecord::Base.send(:replace_bind_variables, statement, vars)
+      end
+    end
+
+    def table_with_custom_primary_key
+      yield(Class.new(Toy) do
+        def self.name
+          'MercedesCar'
+        end
+      end)
+    end
+end
diff --git a/activerecord/test/cases/fixture_set/file_test.rb b/activerecord/test/cases/fixture_set/file_test.rb
new file mode 100644
index 0000000000..92efa8aca7
--- /dev/null
+++ b/activerecord/test/cases/fixture_set/file_test.rb
@@ -0,0 +1,138 @@
+require 'cases/helper'
+require 'tempfile'
+
+module ActiveRecord
+  class FixtureSet
+    class FileTest < ActiveRecord::TestCase
+      def test_open
+        fh = File.open(::File.join(FIXTURES_ROOT, "accounts.yml"))
+        assert_equal 6, fh.to_a.length
+      end
+
+      def test_open_with_block
+        called = false
+        File.open(::File.join(FIXTURES_ROOT, "accounts.yml")) do |fh|
+          called = true
+          assert_equal 6, fh.to_a.length
+        end
+        assert called, 'block called'
+      end
+
+      def test_names
+        File.open(::File.join(FIXTURES_ROOT, "accounts.yml")) do |fh|
+          assert_equal ["signals37",
+                        "unknown",
+                        "rails_core_account",
+                        "last_account",
+                        "rails_core_account_2",
+                        "odegy_account"].sort, fh.to_a.map(&:first).sort
+        end
+      end
+
+      def test_values
+        File.open(::File.join(FIXTURES_ROOT, "accounts.yml")) do |fh|
+          assert_equal [1,2,3,4,5,6].sort, fh.to_a.map(&:last).map { |x|
+            x['id']
+          }.sort
+        end
+      end
+
+      def test_erb_processing
+        File.open(::File.join(FIXTURES_ROOT, "developers.yml")) do |fh|
+          devs = Array.new(8) { |i| "dev_#{i + 3}" }
+          assert_equal [], devs - fh.to_a.map(&:first)
+        end
+      end
+
+      def test_empty_file
+        tmp_yaml ['empty', 'yml'], '' do |t|
+          assert_equal [], File.open(t.path) { |fh| fh.to_a }
+        end
+      end
+
+      # A valid YAML file is not necessarily a value Fixture file. Make sure
+      # an exception is raised if the format is not valid Fixture format.
+      def test_wrong_fixture_format_string
+        tmp_yaml ['empty', 'yml'], 'qwerty' do |t|
+          assert_raises(ActiveRecord::Fixture::FormatError) do
+            File.open(t.path) { |fh| fh.to_a }
+          end
+        end
+      end
+
+      def test_wrong_fixture_format_nested
+        tmp_yaml ['empty', 'yml'], 'one: two' do |t|
+          assert_raises(ActiveRecord::Fixture::FormatError) do
+            File.open(t.path) { |fh| fh.to_a }
+          end
+        end
+      end
+
+      def test_render_context_helper
+        ActiveRecord::FixtureSet.context_class.class_eval do
+          def fixture_helper
+            "Fixture helper"
+          end
+        end
+        yaml = "one:\n  name: <%= fixture_helper %>\n"
+        tmp_yaml ['curious', 'yml'], yaml do |t|
+          golden =
+              [["one", {"name" => "Fixture helper"}]]
+          assert_equal golden, File.open(t.path) { |fh| fh.to_a }
+        end
+        ActiveRecord::FixtureSet.context_class.class_eval do
+          remove_method :fixture_helper
+        end
+      end
+
+      def test_render_context_lookup_scope
+        yaml = <<END
+one:
+  ActiveRecord: <%= defined? ActiveRecord %>
+  ActiveRecord_FixtureSet: <%= defined? ActiveRecord::FixtureSet %>
+  FixtureSet: <%= defined? FixtureSet %>
+  ActiveRecord_FixtureSet_File: <%= defined? ActiveRecord::FixtureSet::File %>
+  File: <%= File.name %>
+END
+
+        golden = [['one', {
+          'ActiveRecord' => 'constant',
+          'ActiveRecord_FixtureSet' => 'constant',
+          'FixtureSet' => nil,
+          'ActiveRecord_FixtureSet_File' => 'constant',
+          'File' => 'File'
+        }]]
+
+        tmp_yaml ['curious', 'yml'], yaml do |t|
+          assert_equal golden, File.open(t.path) { |fh| fh.to_a }
+        end
+      end
+
+      # Make sure that each fixture gets its own rendering context so that
+      # fixtures are independent.
+      def test_independent_render_contexts
+        yaml1 = "<% def leaked_method; 'leak'; end %>\n"
+        yaml2 = "one:\n  name: <%= leaked_method %>\n"
+        tmp_yaml ['leaky', 'yml'], yaml1 do |t1|
+          tmp_yaml ['curious', 'yml'], yaml2 do |t2|
+            File.open(t1.path) { |fh| fh.to_a }
+            assert_raises(NameError) do
+              File.open(t2.path) { |fh| fh.to_a }
+            end
+          end
+        end
+      end
+
+      private
+      def tmp_yaml(name, contents)
+        t = Tempfile.new name
+        t.binmode
+        t.write contents
+        t.close
+        yield t
+      ensure
+        t.close true
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
new file mode 100644
index 0000000000..042fdaf0bb
--- /dev/null
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -0,0 +1,867 @@
+require 'cases/helper'
+require 'models/admin'
+require 'models/admin/account'
+require 'models/admin/randomly_named_c1'
+require 'models/admin/user'
+require 'models/binary'
+require 'models/book'
+require 'models/category'
+require 'models/company'
+require 'models/computer'
+require 'models/course'
+require 'models/developer'
+require 'models/joke'
+require 'models/matey'
+require 'models/parrot'
+require 'models/pirate'
+require 'models/post'
+require 'models/randomly_named_c1'
+require 'models/reply'
+require 'models/ship'
+require 'models/task'
+require 'models/topic'
+require 'models/traffic_light'
+require 'models/treasure'
+require 'tempfile'
+
+class FixturesTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = true
+  self.use_transactional_fixtures = false
+
+  # other_topics fixture should not be included here
+  fixtures :topics, :developers, :accounts, :tasks, :categories, :funny_jokes, :binaries, :traffic_lights
+
+  FIXTURES = %w( accounts binaries companies customers
+                 developers developers_projects entrants
+                 movies projects subscribers topics tasks )
+  MATCH_ATTRIBUTE_NAME = /[a-zA-Z][-\w]*/
+
+  def test_clean_fixtures
+    FIXTURES.each do |name|
+      fixtures = nil
+      assert_nothing_raised { fixtures = create_fixtures(name).first }
+      assert_kind_of(ActiveRecord::FixtureSet, fixtures)
+      fixtures.each { |_name, fixture|
+        fixture.each { |key, value|
+          assert_match(MATCH_ATTRIBUTE_NAME, key)
+        }
+      }
+    end
+  end
+
+  def test_broken_yaml_exception
+    badyaml = Tempfile.new ['foo', '.yml']
+    badyaml.write 'a: : '
+    badyaml.flush
+
+    dir  = File.dirname badyaml.path
+    name = File.basename badyaml.path, '.yml'
+    assert_raises(ActiveRecord::Fixture::FormatError) do
+      ActiveRecord::FixtureSet.create_fixtures(dir, name)
+    end
+  ensure
+    badyaml.close
+    badyaml.unlink
+  end
+
+  def test_create_fixtures
+    fixtures = ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT, "parrots")
+    assert Parrot.find_by_name('Curious George'), 'George is not in the database'
+    assert fixtures.detect { |f| f.name == 'parrots' }, "no fixtures named 'parrots' in #{fixtures.map(&:name).inspect}"
+  end
+
+  def test_multiple_clean_fixtures
+    fixtures_array = nil
+    assert_nothing_raised { fixtures_array = create_fixtures(*FIXTURES) }
+    assert_kind_of(Array, fixtures_array)
+    fixtures_array.each { |fixtures| assert_kind_of(ActiveRecord::FixtureSet, fixtures) }
+  end
+
+  def test_create_symbol_fixtures
+    fixtures = ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT, :collections, :collections => Course) { Course.connection }
+
+    assert Course.find_by_name('Collection'), 'course is not in the database'
+    assert fixtures.detect { |f| f.name == 'collections' }, "no fixtures named 'collections' in #{fixtures.map(&:name).inspect}"
+  end
+
+  def test_attributes
+    topics = create_fixtures("topics").first
+    assert_equal("The First Topic", topics["first"]["title"])
+    assert_nil(topics["second"]["author_email_address"])
+  end
+
+  def test_inserts
+    create_fixtures("topics")
+    first_row = ActiveRecord::Base.connection.select_one("SELECT * FROM topics WHERE author_name = 'David'")
+    assert_equal("The First Topic", first_row["title"])
+
+    second_row = ActiveRecord::Base.connection.select_one("SELECT * FROM topics WHERE author_name = 'Mary'")
+    assert_nil(second_row["author_email_address"])
+  end
+
+  if ActiveRecord::Base.connection.supports_migrations?
+    def test_inserts_with_pre_and_suffix
+      # Reset cache to make finds on the new table work
+      ActiveRecord::FixtureSet.reset_cache
+
+      ActiveRecord::Base.connection.create_table :prefix_other_topics_suffix do |t|
+        t.column :title, :string
+        t.column :author_name, :string
+        t.column :author_email_address, :string
+        t.column :written_on, :datetime
+        t.column :bonus_time, :time
+        t.column :last_read, :date
+        t.column :content, :string
+        t.column :approved, :boolean, :default => true
+        t.column :replies_count, :integer, :default => 0
+        t.column :parent_id, :integer
+        t.column :type, :string, :limit => 50
+      end
+
+      # Store existing prefix/suffix
+      old_prefix = ActiveRecord::Base.table_name_prefix
+      old_suffix = ActiveRecord::Base.table_name_suffix
+
+      # Set a prefix/suffix we can test against
+      ActiveRecord::Base.table_name_prefix = 'prefix_'
+      ActiveRecord::Base.table_name_suffix = '_suffix'
+
+      other_topic_klass = Class.new(ActiveRecord::Base) do
+        def self.name
+          "OtherTopic"
+        end
+      end
+
+      topics = [create_fixtures("other_topics")].flatten.first
+
+      # This checks for a caching problem which causes a bug in the fixtures
+      # class-level configuration helper.
+      assert_not_nil topics, "Fixture data inserted, but fixture objects not returned from create"
+
+      first_row = ActiveRecord::Base.connection.select_one("SELECT * FROM prefix_other_topics_suffix WHERE author_name = 'David'")
+      assert_not_nil first_row, "The prefix_other_topics_suffix table appears to be empty despite create_fixtures: the row with author_name = 'David' was not found"
+      assert_equal("The First Topic", first_row["title"])
+
+      second_row = ActiveRecord::Base.connection.select_one("SELECT * FROM prefix_other_topics_suffix WHERE author_name = 'Mary'")
+      assert_nil(second_row["author_email_address"])
+
+      assert_equal :prefix_other_topics_suffix, topics.table_name.to_sym
+      # This assertion should preferably be the last in the list, because calling
+      # other_topic_klass.table_name sets a class-level instance variable
+      assert_equal :prefix_other_topics_suffix, other_topic_klass.table_name.to_sym
+
+    ensure
+      # Restore prefix/suffix to its previous values
+      ActiveRecord::Base.table_name_prefix = old_prefix
+      ActiveRecord::Base.table_name_suffix = old_suffix
+
+      ActiveRecord::Base.connection.drop_table :prefix_other_topics_suffix rescue nil
+    end
+  end
+
+  def test_insert_with_datetime
+    create_fixtures("tasks")
+    first = Task.find(1)
+    assert first
+  end
+
+  def test_logger_level_invariant
+    level = ActiveRecord::Base.logger.level
+    create_fixtures('topics')
+    assert_equal level, ActiveRecord::Base.logger.level
+  end
+
+  def test_instantiation
+    topics = create_fixtures("topics").first
+    assert_kind_of Topic, topics["first"].find
+  end
+
+  def test_complete_instantiation
+    assert_equal "The First Topic", @first.title
+  end
+
+  def test_fixtures_from_root_yml_with_instantiation
+    # assert_equal 2, @accounts.size
+    assert_equal 50, @unknown.credit_limit
+  end
+
+  def test_erb_in_fixtures
+    assert_equal "fixture_5", @dev_5.name
+  end
+
+  def test_empty_yaml_fixture
+    assert_not_nil ActiveRecord::FixtureSet.new( Account.connection, "accounts", Account, FIXTURES_ROOT + "/naked/yml/accounts")
+  end
+
+  def test_empty_yaml_fixture_with_a_comment_in_it
+    assert_not_nil ActiveRecord::FixtureSet.new( Account.connection, "companies", Company, FIXTURES_ROOT + "/naked/yml/companies")
+  end
+
+  def test_nonexistent_fixture_file
+    nonexistent_fixture_path = FIXTURES_ROOT + "/imnothere"
+
+    #sanity check to make sure that this file never exists
+    assert Dir[nonexistent_fixture_path+"*"].empty?
+
+    assert_raise(Errno::ENOENT) do
+      ActiveRecord::FixtureSet.new( Account.connection, "companies", Company, nonexistent_fixture_path)
+    end
+  end
+
+  def test_dirty_dirty_yaml_file
+    assert_raise(ActiveRecord::Fixture::FormatError) do
+      ActiveRecord::FixtureSet.new( Account.connection, "courses", Course, FIXTURES_ROOT + "/naked/yml/courses")
+    end
+  end
+
+  def test_omap_fixtures
+    assert_nothing_raised do
+      fixtures = ActiveRecord::FixtureSet.new(Account.connection, 'categories', Category, FIXTURES_ROOT + "/categories_ordered")
+
+      fixtures.each.with_index do |(name, fixture), i|
+        assert_equal "fixture_no_#{i}", name
+        assert_equal "Category #{i}", fixture['name']
+      end
+    end
+  end
+
+  def test_yml_file_in_subdirectory
+    assert_equal(categories(:sub_special_1).name, "A special category in a subdir file")
+    assert_equal(categories(:sub_special_1).class, SpecialCategory)
+  end
+
+  def test_subsubdir_file_with_arbitrary_name
+    assert_equal(categories(:sub_special_3).name, "A special category in an arbitrarily named subsubdir file")
+    assert_equal(categories(:sub_special_3).class, SpecialCategory)
+  end
+
+  def test_binary_in_fixtures
+    data = File.open(ASSETS_ROOT + "/flowers.jpg", 'rb') { |f| f.read }
+    data.force_encoding('ASCII-8BIT')
+    data.freeze
+    assert_equal data, @flowers.data
+  end
+
+  def test_serialized_fixtures
+    assert_equal ["Green", "Red", "Orange"], traffic_lights(:uk).state
+  end
+
+  def test_fixtures_are_set_up_with_database_env_variable
+    db_url_tmp = ENV['DATABASE_URL']
+    ENV['DATABASE_URL'] = "sqlite3::memory:"
+    ActiveRecord::Base.stubs(:configurations).returns({})
+    test_case = Class.new(ActiveRecord::TestCase) do
+      fixtures :accounts
+
+      def test_fixtures
+        assert accounts(:signals37)
+      end
+    end
+
+    result = test_case.new(:test_fixtures).run
+
+    assert result.passed?, "Expected #{result.name} to pass:\n#{result}"
+  ensure
+    ENV['DATABASE_URL'] = db_url_tmp
+  end
+end
+
+class HasManyThroughFixture < ActiveSupport::TestCase
+  def make_model(name)
+    Class.new(ActiveRecord::Base) { define_singleton_method(:name) { name } }
+  end
+
+  def test_has_many_through
+    pt = make_model "ParrotTreasure"
+    parrot = make_model "Parrot"
+    treasure = make_model "Treasure"
+
+    pt.table_name = "parrots_treasures"
+    pt.belongs_to :parrot, :class => parrot
+    pt.belongs_to :treasure, :class => treasure
+
+    parrot.has_many :parrot_treasures, :class => pt
+    parrot.has_many :treasures, :through => :parrot_treasures
+
+    parrots = File.join FIXTURES_ROOT, 'parrots'
+
+    fs = ActiveRecord::FixtureSet.new parrot.connection, "parrots", parrot, parrots
+    rows = fs.table_rows
+    assert_equal load_has_and_belongs_to_many['parrots_treasures'], rows['parrots_treasures']
+  end
+
+  def load_has_and_belongs_to_many
+    parrot = make_model "Parrot"
+    parrot.has_and_belongs_to_many :treasures
+
+    parrots = File.join FIXTURES_ROOT, 'parrots'
+
+    fs = ActiveRecord::FixtureSet.new parrot.connection, "parrots", parrot, parrots
+    fs.table_rows
+  end
+end
+
+if Account.connection.respond_to?(:reset_pk_sequence!)
+  class FixturesResetPkSequenceTest < ActiveRecord::TestCase
+    fixtures :accounts
+    fixtures :companies
+
+    def setup
+      @instances = [Account.new(:credit_limit => 50), Company.new(:name => 'RoR Consulting')]
+      ActiveRecord::FixtureSet.reset_cache # make sure tables get reinitialized
+    end
+
+    def test_resets_to_min_pk_with_specified_pk_and_sequence
+      @instances.each do |instance|
+        model = instance.class
+        model.delete_all
+        model.connection.reset_pk_sequence!(model.table_name, model.primary_key, model.sequence_name)
+
+        instance.save!
+        assert_equal 1, instance.id, "Sequence reset for #{model.table_name} failed."
+      end
+    end
+
+    def test_resets_to_min_pk_with_default_pk_and_sequence
+      @instances.each do |instance|
+        model = instance.class
+        model.delete_all
+        model.connection.reset_pk_sequence!(model.table_name)
+
+        instance.save!
+        assert_equal 1, instance.id, "Sequence reset for #{model.table_name} failed."
+      end
+    end
+
+    def test_create_fixtures_resets_sequences_when_not_cached
+      @instances.each do |instance|
+        max_id = create_fixtures(instance.class.table_name).first.fixtures.inject(0) do |_max_id, (_, fixture)|
+          fixture_id = fixture['id'].to_i
+          fixture_id > _max_id ? fixture_id : _max_id
+        end
+
+        # Clone the last fixture to check that it gets the next greatest id.
+        instance.save!
+        assert_equal max_id + 1, instance.id, "Sequence reset for #{instance.class.table_name} failed."
+      end
+    end
+  end
+end
+
+class FixturesWithoutInstantiationTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = false
+  fixtures :topics, :developers, :accounts
+
+  def test_without_complete_instantiation
+    assert !defined?(@first)
+    assert !defined?(@topics)
+    assert !defined?(@developers)
+    assert !defined?(@accounts)
+  end
+
+  def test_fixtures_from_root_yml_without_instantiation
+    assert !defined?(@unknown), "@unknown is not defined"
+  end
+
+  def test_visibility_of_accessor_method
+    assert_equal false, respond_to?(:topics, false), "should be private method"
+    assert_equal true, respond_to?(:topics, true), "confirm to respond surely"
+  end
+
+  def test_accessor_methods
+    assert_equal "The First Topic", topics(:first).title
+    assert_equal "Jamis", developers(:jamis).name
+    assert_equal 50, accounts(:signals37).credit_limit
+  end
+
+  def test_accessor_methods_with_multiple_args
+    assert_equal 2, topics(:first, :second).size
+    assert_raise(StandardError) { topics([:first, :second]) }
+  end
+
+  def test_reloading_fixtures_through_accessor_methods
+    assert_equal "The First Topic", topics(:first).title
+    @loaded_fixtures['topics']['first'].expects(:find).returns(stub(:title => "Fresh Topic!"))
+    assert_equal "Fresh Topic!", topics(:first, true).title
+  end
+end
+
+class FixturesWithoutInstanceInstantiationTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = true
+  self.use_instantiated_fixtures = :no_instances
+
+  fixtures :topics, :developers, :accounts
+
+  def test_without_instance_instantiation
+    assert !defined?(@first), "@first is not defined"
+  end
+end
+
+class TransactionalFixturesTest < ActiveRecord::TestCase
+  self.use_instantiated_fixtures = true
+  self.use_transactional_fixtures = true
+
+  fixtures :topics
+
+  def test_destroy
+    assert_not_nil @first
+    @first.destroy
+  end
+
+  def test_destroy_just_kidding
+    assert_not_nil @first
+  end
+end
+
+class MultipleFixturesTest < ActiveRecord::TestCase
+  fixtures :topics
+  fixtures :developers, :accounts
+
+  def test_fixture_table_names
+    assert_equal %w(topics developers accounts), fixture_table_names
+  end
+end
+
+class SetupTest < ActiveRecord::TestCase
+  # fixtures :topics
+
+  def setup
+    @first = true
+  end
+
+  def test_nothing
+  end
+end
+
+class SetupSubclassTest < SetupTest
+  def setup
+    super
+    @second = true
+  end
+
+  def test_subclassing_should_preserve_setups
+    assert @first
+    assert @second
+  end
+end
+
+
+class OverlappingFixturesTest < ActiveRecord::TestCase
+  fixtures :topics, :developers
+  fixtures :developers, :accounts
+
+  def test_fixture_table_names
+    assert_equal %w(topics developers accounts), fixture_table_names
+  end
+end
+
+class ForeignKeyFixturesTest < ActiveRecord::TestCase
+  fixtures :fk_test_has_pk, :fk_test_has_fk
+
+  # if foreign keys are implemented and fixtures
+  # are not deleted in reverse order then this test
+  # case will raise StatementInvalid
+
+  def test_number1
+    assert true
+  end
+
+  def test_number2
+    assert true
+  end
+end
+
+class OverRideFixtureMethodTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  def topics(name)
+    topic = super
+    topic.title = 'omg'
+    topic
+  end
+
+  def test_fixture_methods_can_be_overridden
+    x = topics :first
+    assert_equal 'omg', x.title
+  end
+end
+
+class CheckSetTableNameFixturesTest < ActiveRecord::TestCase
+  set_fixture_class :funny_jokes => Joke
+  fixtures :funny_jokes
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our set_fixture_class
+  self.use_transactional_fixtures = false
+
+  def test_table_method
+    assert_kind_of Joke, funny_jokes(:a_joke)
+  end
+end
+
+class FixtureNameIsNotTableNameFixturesTest < ActiveRecord::TestCase
+  set_fixture_class :items => Book
+  fixtures :items
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our set_fixture_class
+  self.use_transactional_fixtures = false
+
+  def test_named_accessor
+    assert_kind_of Book, items(:dvd)
+  end
+end
+
+class FixtureNameIsNotTableNameMultipleFixturesTest < ActiveRecord::TestCase
+  set_fixture_class :items => Book, :funny_jokes => Joke
+  fixtures :items, :funny_jokes
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our set_fixture_class
+  self.use_transactional_fixtures = false
+
+  def test_named_accessor_of_differently_named_fixture
+    assert_kind_of Book, items(:dvd)
+  end
+
+  def test_named_accessor_of_same_named_fixture
+    assert_kind_of Joke, funny_jokes(:a_joke)
+  end
+end
+
+class CustomConnectionFixturesTest < ActiveRecord::TestCase
+  set_fixture_class :courses => Course
+  fixtures :courses
+  self.use_transactional_fixtures = false
+
+  def test_leaky_destroy
+    assert_nothing_raised { courses(:ruby) }
+    courses(:ruby).destroy
+  end
+
+  def test_it_twice_in_whatever_order_to_check_for_fixture_leakage
+    test_leaky_destroy
+  end
+end
+
+class TransactionalFixturesOnCustomConnectionTest < ActiveRecord::TestCase
+  set_fixture_class :courses => Course
+  fixtures :courses
+  self.use_transactional_fixtures = true
+
+  def test_leaky_destroy
+    assert_nothing_raised { courses(:ruby) }
+    courses(:ruby).destroy
+  end
+
+  def test_it_twice_in_whatever_order_to_check_for_fixture_leakage
+    test_leaky_destroy
+  end
+end
+
+class InvalidTableNameFixturesTest < ActiveRecord::TestCase
+  fixtures :funny_jokes
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our lack of set_fixture_class
+  self.use_transactional_fixtures = false
+
+  def test_raises_error
+    assert_raise ActiveRecord::FixtureClassNotFound do
+      funny_jokes(:a_joke)
+    end
+  end
+end
+
+class CheckEscapedYamlFixturesTest < ActiveRecord::TestCase
+  set_fixture_class :funny_jokes => Joke
+  fixtures :funny_jokes
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  # and thus takes into account our set_fixture_class
+  self.use_transactional_fixtures = false
+
+  def test_proper_escaped_fixture
+    assert_equal "The \\n Aristocrats\nAte the candy\n", funny_jokes(:another_joke).name
+  end
+end
+
+class DevelopersProject; end
+class ManyToManyFixturesWithClassDefined < ActiveRecord::TestCase
+  fixtures :developers_projects
+
+  def test_this_should_run_cleanly
+    assert true
+  end
+end
+
+class FixturesBrokenRollbackTest < ActiveRecord::TestCase
+  def blank_setup
+    @fixture_connections = [ActiveRecord::Base.connection]
+  end
+  alias_method :ar_setup_fixtures, :setup_fixtures
+  alias_method :setup_fixtures, :blank_setup
+  alias_method :setup, :blank_setup
+
+  def blank_teardown; end
+  alias_method :ar_teardown_fixtures, :teardown_fixtures
+  alias_method :teardown_fixtures, :blank_teardown
+  alias_method :teardown, :blank_teardown
+
+  def test_no_rollback_in_teardown_unless_transaction_active
+    assert_equal 0, ActiveRecord::Base.connection.open_transactions
+    assert_raise(RuntimeError) { ar_setup_fixtures }
+    assert_equal 0, ActiveRecord::Base.connection.open_transactions
+    assert_nothing_raised { ar_teardown_fixtures }
+    assert_equal 0, ActiveRecord::Base.connection.open_transactions
+  end
+
+  private
+    def load_fixtures(config)
+      raise 'argh'
+    end
+end
+
+class LoadAllFixturesTest < ActiveRecord::TestCase
+  def test_all_there
+    self.class.fixture_path = FIXTURES_ROOT + "/all"
+    self.class.fixtures :all
+
+    if File.symlink? FIXTURES_ROOT + "/all/admin"
+      assert_equal %w(admin/accounts admin/users developers people tasks), fixture_table_names.sort
+    end
+  ensure
+    ActiveRecord::FixtureSet.reset_cache
+  end
+end
+
+class LoadAllFixturesWithPathnameTest < ActiveRecord::TestCase
+  def test_all_there
+    self.class.fixture_path = Pathname.new(FIXTURES_ROOT).join('all')
+    self.class.fixtures :all
+
+    if File.symlink? FIXTURES_ROOT + "/all/admin"
+      assert_equal %w(admin/accounts admin/users developers people tasks), fixture_table_names.sort
+    end
+  ensure
+    ActiveRecord::FixtureSet.reset_cache
+  end
+end
+
+class FasterFixturesTest < ActiveRecord::TestCase
+  fixtures :categories, :authors
+
+  def load_extra_fixture(name)
+    fixture = create_fixtures(name).first
+    assert fixture.is_a?(ActiveRecord::FixtureSet)
+    @loaded_fixtures[fixture.table_name] = fixture
+  end
+
+  def test_cache
+    assert ActiveRecord::FixtureSet.fixture_is_cached?(ActiveRecord::Base.connection, 'categories')
+    assert ActiveRecord::FixtureSet.fixture_is_cached?(ActiveRecord::Base.connection, 'authors')
+
+    assert_no_queries do
+      create_fixtures('categories')
+      create_fixtures('authors')
+    end
+
+    load_extra_fixture('posts')
+    assert ActiveRecord::FixtureSet.fixture_is_cached?(ActiveRecord::Base.connection, 'posts')
+    self.class.setup_fixture_accessors :posts
+    assert_equal 'Welcome to the weblog', posts(:welcome).title
+  end
+end
+
+class FoxyFixturesTest < ActiveRecord::TestCase
+  fixtures :parrots, :parrots_pirates, :pirates, :treasures, :mateys, :ships, :computers, :developers, :"admin/accounts", :"admin/users"
+
+  if ActiveRecord::Base.connection.adapter_name == 'PostgreSQL'
+    require 'models/uuid_parent'
+    require 'models/uuid_child'
+    fixtures :uuid_parents, :uuid_children 
+  end
+
+  def test_identifies_strings
+    assert_equal(ActiveRecord::FixtureSet.identify("foo"), ActiveRecord::FixtureSet.identify("foo"))
+    assert_not_equal(ActiveRecord::FixtureSet.identify("foo"), ActiveRecord::FixtureSet.identify("FOO"))
+  end
+
+  def test_identifies_symbols
+    assert_equal(ActiveRecord::FixtureSet.identify(:foo), ActiveRecord::FixtureSet.identify(:foo))
+  end
+
+  def test_identifies_consistently
+    assert_equal 207281424, ActiveRecord::FixtureSet.identify(:ruby)
+    assert_equal 1066363776, ActiveRecord::FixtureSet.identify(:sapphire_2)
+
+    assert_equal 'f92b6bda-0d0d-5fe1-9124-502b18badded', ActiveRecord::FixtureSet.identify(:daddy, :uuid)
+    assert_equal 'b4b10018-ad47-595d-b42f-d8bdaa6d01bf', ActiveRecord::FixtureSet.identify(:sonny, :uuid)
+  end
+
+  TIMESTAMP_COLUMNS = %w(created_at created_on updated_at updated_on)
+
+  def test_populates_timestamp_columns
+    TIMESTAMP_COLUMNS.each do |property|
+      assert_not_nil(parrots(:george).send(property), "should set #{property}")
+    end
+  end
+
+  def test_does_not_populate_timestamp_columns_if_model_has_set_record_timestamps_to_false
+    TIMESTAMP_COLUMNS.each do |property|
+      assert_nil(ships(:black_pearl).send(property), "should not set #{property}")
+    end
+  end
+
+  def test_populates_all_columns_with_the_same_time
+    last = nil
+
+    TIMESTAMP_COLUMNS.each do |property|
+      current = parrots(:george).send(property)
+      last ||= current
+
+      assert_equal(last, current)
+      last = current
+    end
+  end
+
+  def test_only_populates_columns_that_exist
+    assert_not_nil(pirates(:blackbeard).created_on)
+    assert_not_nil(pirates(:blackbeard).updated_on)
+  end
+
+  def test_preserves_existing_fixture_data
+    assert_equal(2.weeks.ago.to_date, pirates(:redbeard).created_on.to_date)
+    assert_equal(2.weeks.ago.to_date, pirates(:redbeard).updated_on.to_date)
+  end
+
+  def test_generates_unique_ids
+    assert_not_nil(parrots(:george).id)
+    assert_not_equal(parrots(:george).id, parrots(:louis).id)
+  end
+
+  def test_automatically_sets_primary_key
+    assert_not_nil(ships(:black_pearl))
+  end
+
+  def test_preserves_existing_primary_key
+    assert_equal(2, ships(:interceptor).id)
+  end
+
+  def test_resolves_belongs_to_symbols
+    assert_equal(parrots(:george), pirates(:blackbeard).parrot)
+  end
+
+  def test_ignores_belongs_to_symbols_if_association_and_foreign_key_are_named_the_same
+    assert_equal(developers(:david), computers(:workstation).developer)
+  end
+
+  def test_supports_join_tables
+    assert(pirates(:blackbeard).parrots.include?(parrots(:george)))
+    assert(pirates(:blackbeard).parrots.include?(parrots(:louis)))
+    assert(parrots(:george).pirates.include?(pirates(:blackbeard)))
+  end
+
+  def test_supports_inline_habtm
+    assert(parrots(:george).treasures.include?(treasures(:diamond)))
+    assert(parrots(:george).treasures.include?(treasures(:sapphire)))
+    assert(!parrots(:george).treasures.include?(treasures(:ruby)))
+  end
+
+  def test_supports_inline_habtm_with_specified_id
+    assert(parrots(:polly).treasures.include?(treasures(:ruby)))
+    assert(parrots(:polly).treasures.include?(treasures(:sapphire)))
+    assert(!parrots(:polly).treasures.include?(treasures(:diamond)))
+  end
+
+  def test_supports_yaml_arrays
+    assert(parrots(:louis).treasures.include?(treasures(:diamond)))
+    assert(parrots(:louis).treasures.include?(treasures(:sapphire)))
+  end
+
+  def test_strips_DEFAULTS_key
+    assert_raise(StandardError) { parrots(:DEFAULTS) }
+
+    # this lets us do YAML defaults and not have an extra fixture entry
+    %w(sapphire ruby).each { |t| assert(parrots(:davey).treasures.include?(treasures(t))) }
+  end
+
+  def test_supports_label_interpolation
+    assert_equal("frederick", parrots(:frederick).name)
+  end
+
+  def test_supports_label_string_interpolation
+    assert_equal("X marks the spot!", pirates(:mark).catchphrase)
+  end
+
+  def test_supports_polymorphic_belongs_to
+    assert_equal(pirates(:redbeard), treasures(:sapphire).looter)
+    assert_equal(parrots(:louis), treasures(:ruby).looter)
+  end
+
+  def test_only_generates_a_pk_if_necessary
+    m = Matey.first
+    m.pirate = pirates(:blackbeard)
+    m.target = pirates(:redbeard)
+  end
+
+  def test_supports_sti
+    assert_kind_of DeadParrot, parrots(:polly)
+    assert_equal pirates(:blackbeard), parrots(:polly).killer
+  end
+
+  def test_namespaced_models
+    assert admin_accounts(:signals37).users.include?(admin_users(:david))
+    assert_equal 2, admin_accounts(:signals37).users.size
+  end
+end
+
+class ActiveSupportSubclassWithFixturesTest < ActiveRecord::TestCase
+  fixtures :parrots
+
+  # This seemingly useless assertion catches a bug that caused the fixtures
+  # setup code call nil[]
+  def test_foo
+    assert_equal parrots(:louis), Parrot.find_by_name("King Louis")
+  end
+end
+
+class FixtureLoadingTest < ActiveRecord::TestCase
+  def test_logs_message_for_failed_dependency_load
+    ActiveRecord::TestCase.expects(:require_dependency).with(:does_not_exist).raises(LoadError)
+    ActiveRecord::Base.logger.expects(:warn)
+    ActiveRecord::TestCase.try_to_load_dependency(:does_not_exist)
+  end
+
+  def test_does_not_logs_message_for_successful_dependency_load
+    ActiveRecord::TestCase.expects(:require_dependency).with(:works_out_fine)
+    ActiveRecord::Base.logger.expects(:warn).never
+    ActiveRecord::TestCase.try_to_load_dependency(:works_out_fine)
+  end
+end
+
+class CustomNameForFixtureOrModelTest < ActiveRecord::TestCase
+  ActiveRecord::FixtureSet.reset_cache
+
+  set_fixture_class :randomly_named_a9         =>
+                        ClassNameThatDoesNotFollowCONVENTIONS,
+                    :'admin/randomly_named_a9' =>
+                        Admin::ClassNameThatDoesNotFollowCONVENTIONS,
+                    'admin/randomly_named_b0'  =>
+                        Admin::ClassNameThatDoesNotFollowCONVENTIONS
+
+  fixtures :randomly_named_a9, 'admin/randomly_named_a9',
+           :'admin/randomly_named_b0'
+
+  def test_named_accessor_for_randomly_named_fixture_and_class
+    assert_kind_of ClassNameThatDoesNotFollowCONVENTIONS,
+                   randomly_named_a9(:first_instance)
+  end
+
+  def test_named_accessor_for_randomly_named_namespaced_fixture_and_class
+    assert_kind_of Admin::ClassNameThatDoesNotFollowCONVENTIONS,
+                   admin_randomly_named_a9(:first_instance)
+    assert_kind_of Admin::ClassNameThatDoesNotFollowCONVENTIONS,
+                   admin_randomly_named_b0(:second_instance)
+  end
+
+  def test_table_name_is_defined_in_the_model
+    assert_equal 'randomly_named_table', ActiveRecord::FixtureSet::all_loaded_fixtures["admin/randomly_named_a9"].table_name
+    assert_equal 'randomly_named_table', Admin::ClassNameThatDoesNotFollowCONVENTIONS.table_name
+  end
+end
diff --git a/activerecord/test/cases/forbidden_attributes_protection_test.rb b/activerecord/test/cases/forbidden_attributes_protection_test.rb
new file mode 100644
index 0000000000..981a75faf6
--- /dev/null
+++ b/activerecord/test/cases/forbidden_attributes_protection_test.rb
@@ -0,0 +1,69 @@
+require 'cases/helper'
+require 'active_support/core_ext/hash/indifferent_access'
+require 'models/person'
+require 'models/company'
+
+class ProtectedParams < ActiveSupport::HashWithIndifferentAccess
+  attr_accessor :permitted
+  alias :permitted? :permitted
+
+  def initialize(attributes)
+    super(attributes)
+    @permitted = false
+  end
+
+  def permit!
+    @permitted = true
+    self
+  end
+
+  def dup
+    super.tap do |duplicate|
+      duplicate.instance_variable_set :@permitted, @permitted
+    end
+  end
+end
+
+class ForbiddenAttributesProtectionTest < ActiveRecord::TestCase
+  def test_forbidden_attributes_cannot_be_used_for_mass_assignment
+    params = ProtectedParams.new(first_name: 'Guille', gender: 'm')
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Person.new(params)
+    end
+  end
+
+  def test_permitted_attributes_can_be_used_for_mass_assignment
+    params = ProtectedParams.new(first_name: 'Guille', gender: 'm')
+    params.permit!
+    person = Person.new(params)
+
+    assert_equal 'Guille', person.first_name
+    assert_equal 'm', person.gender
+  end
+
+  def test_forbidden_attributes_cannot_be_used_for_sti_inheritance_column
+    params = ProtectedParams.new(type: 'Client')
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Company.new(params)
+    end
+  end
+
+  def test_permitted_attributes_can_be_used_for_sti_inheritance_column
+    params = ProtectedParams.new(type: 'Client')
+    params.permit!
+    person = Company.new(params)
+    assert_equal person.class, Client
+  end
+
+  def test_regular_hash_should_still_be_used_for_mass_assignment
+    person = Person.new(first_name: 'Guille', gender: 'm')
+
+    assert_equal 'Guille', person.first_name
+    assert_equal 'm', person.gender
+  end
+
+  def test_blank_attributes_should_not_raise
+    person = Person.new
+    assert_nil person.assign_attributes(ProtectedParams.new({}))
+  end
+end
diff --git a/activerecord/test/cases/habtm_destroy_order_test.rb b/activerecord/test/cases/habtm_destroy_order_test.rb
new file mode 100644
index 0000000000..2ce0de360e
--- /dev/null
+++ b/activerecord/test/cases/habtm_destroy_order_test.rb
@@ -0,0 +1,61 @@
+require "cases/helper"
+require "models/lesson"
+require "models/student"
+
+class HabtmDestroyOrderTest < ActiveRecord::TestCase
+  test "may not delete a lesson with students" do
+    sicp = Lesson.new(:name => "SICP")
+    ben = Student.new(:name => "Ben Bitdiddle")
+    sicp.students << ben
+    sicp.save!
+    assert_raises LessonError do
+      assert_no_difference('Lesson.count') do
+        sicp.destroy
+      end
+    end
+    assert !sicp.destroyed?
+  end
+
+  test 'should not raise error if have foreign key in the join table' do
+    student = Student.new(:name => "Ben Bitdiddle")
+    lesson = Lesson.new(:name => "SICP")
+    lesson.students << student
+    lesson.save!
+    assert_nothing_raised do
+      student.destroy
+    end
+  end
+
+  test "not destroying a student with lessons leaves student<=>lesson association intact" do
+    # test a normal before_destroy doesn't destroy the habtm joins
+    begin
+      sicp = Lesson.new(:name => "SICP")
+      ben = Student.new(:name => "Ben Bitdiddle")
+      # add a before destroy to student
+      Student.class_eval do
+        before_destroy do
+          raise ActiveRecord::Rollback unless lessons.empty?
+        end
+      end
+      ben.lessons << sicp
+      ben.save!
+      ben.destroy
+      assert !ben.reload.lessons.empty?
+    ensure
+      # get rid of it so Student is still like it was
+      Student.reset_callbacks(:destroy)
+    end
+  end
+
+  test "not destroying a lesson with students leaves student<=>lesson association intact" do
+    # test a more aggressive before_destroy  doesn't destroy the habtm joins and still throws the exception
+    sicp = Lesson.new(:name => "SICP")
+    ben = Student.new(:name => "Ben Bitdiddle")
+    sicp.students << ben
+    sicp.save!
+    assert_raises LessonError do
+      sicp.destroy
+    end
+    assert !sicp.reload.students.empty?
+  end
+end
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
new file mode 100644
index 0000000000..6a8aff4b69
--- /dev/null
+++ b/activerecord/test/cases/helper.rb
@@ -0,0 +1,203 @@
+require File.expand_path('../../../../load_paths', __FILE__)
+
+require 'config'
+
+require 'active_support/testing/autorun'
+require 'stringio'
+
+require 'active_record'
+require 'cases/test_case'
+require 'active_support/dependencies'
+require 'active_support/logger'
+require 'active_support/core_ext/string/strip'
+
+require 'support/config'
+require 'support/connection'
+
+# TODO: Move all these random hacks into the ARTest namespace and into the support/ dir
+
+Thread.abort_on_exception = true
+
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+# Disable available locale checks to avoid warnings running the test suite.
+I18n.enforce_available_locales = false
+
+# Connect to the database
+ARTest.connect
+
+# Quote "type" if it's a reserved word for the current connection.
+QUOTED_TYPE = ActiveRecord::Base.connection.quote_column_name('type')
+
+def current_adapter?(*types)
+  types.any? do |type|
+    ActiveRecord::ConnectionAdapters.const_defined?(type) &&
+      ActiveRecord::Base.connection.is_a?(ActiveRecord::ConnectionAdapters.const_get(type))
+  end
+end
+
+def in_memory_db?
+  current_adapter?(:SQLite3Adapter) &&
+  ActiveRecord::Base.connection_pool.spec.config[:database] == ":memory:"
+end
+
+def mysql_56?
+  current_adapter?(:Mysql2Adapter) &&
+    ActiveRecord::Base.connection.send(:version).join(".") >= "5.6.0"
+end
+
+def supports_savepoints?
+  ActiveRecord::Base.connection.supports_savepoints?
+end
+
+def with_env_tz(new_tz = 'US/Eastern')
+  old_tz, ENV['TZ'] = ENV['TZ'], new_tz
+  yield
+ensure
+  old_tz ? ENV['TZ'] = old_tz : ENV.delete('TZ')
+end
+
+def with_timezone_config(cfg)
+  verify_default_timezone_config
+
+  old_default_zone = ActiveRecord::Base.default_timezone
+  old_awareness = ActiveRecord::Base.time_zone_aware_attributes
+  old_zone = Time.zone
+
+  if cfg.has_key?(:default)
+    ActiveRecord::Base.default_timezone = cfg[:default]
+  end
+  if cfg.has_key?(:aware_attributes)
+    ActiveRecord::Base.time_zone_aware_attributes = cfg[:aware_attributes]
+  end
+  if cfg.has_key?(:zone)
+    Time.zone = cfg[:zone]
+  end
+  yield
+ensure
+  ActiveRecord::Base.default_timezone = old_default_zone
+  ActiveRecord::Base.time_zone_aware_attributes = old_awareness
+  Time.zone = old_zone
+end
+
+# This method makes sure that tests don't leak global state related to time zones.
+EXPECTED_ZONE = nil
+EXPECTED_DEFAULT_TIMEZONE = :utc
+EXPECTED_TIME_ZONE_AWARE_ATTRIBUTES = false
+def verify_default_timezone_config
+  if Time.zone != EXPECTED_ZONE
+    $stderr.puts <<-MSG
+\n#{self.to_s}
+    Global state `Time.zone` was leaked.
+      Expected: #{EXPECTED_ZONE}
+      Got: #{Time.zone}
+    MSG
+  end
+  if ActiveRecord::Base.default_timezone != EXPECTED_DEFAULT_TIMEZONE
+    $stderr.puts <<-MSG
+\n#{self.to_s}
+    Global state `ActiveRecord::Base.default_timezone` was leaked.
+      Expected: #{EXPECTED_DEFAULT_TIMEZONE}
+      Got: #{ActiveRecord::Base.default_timezone}
+    MSG
+  end
+  if ActiveRecord::Base.time_zone_aware_attributes != EXPECTED_TIME_ZONE_AWARE_ATTRIBUTES
+    $stderr.puts <<-MSG
+\n#{self.to_s}
+    Global state `ActiveRecord::Base.time_zone_aware_attributes` was leaked.
+      Expected: #{EXPECTED_TIME_ZONE_AWARE_ATTRIBUTES}
+      Got: #{ActiveRecord::Base.time_zone_aware_attributes}
+    MSG
+  end
+end
+
+def enable_uuid_ossp!(connection)
+  return false unless connection.supports_extensions?
+  return true if connection.extension_enabled?('uuid-ossp')
+
+  connection.enable_extension 'uuid-ossp'
+  connection.commit_db_transaction
+  connection.reconnect!
+end
+
+unless ENV['FIXTURE_DEBUG']
+  module ActiveRecord::TestFixtures::ClassMethods
+    def try_to_load_dependency_with_silence(*args)
+      old = ActiveRecord::Base.logger.level
+      ActiveRecord::Base.logger.level = ActiveSupport::Logger::ERROR
+      try_to_load_dependency_without_silence(*args)
+      ActiveRecord::Base.logger.level = old
+    end
+
+    alias_method_chain :try_to_load_dependency, :silence
+  end
+end
+
+require "cases/validations_repair_helper"
+class ActiveSupport::TestCase
+  include ActiveRecord::TestFixtures
+  include ActiveRecord::ValidationsRepairHelper
+
+  self.fixture_path = FIXTURES_ROOT
+  self.use_instantiated_fixtures  = false
+  self.use_transactional_fixtures = true
+
+  def create_fixtures(*fixture_set_names, &block)
+    ActiveRecord::FixtureSet.create_fixtures(ActiveSupport::TestCase.fixture_path, fixture_set_names, fixture_class_names, &block)
+  end
+end
+
+def load_schema
+  # silence verbose schema loading
+  original_stdout = $stdout
+  $stdout = StringIO.new
+
+  adapter_name = ActiveRecord::Base.connection.adapter_name.downcase
+  adapter_specific_schema_file = SCHEMA_ROOT + "/#{adapter_name}_specific_schema.rb"
+
+  load SCHEMA_ROOT + "/schema.rb"
+
+  if File.exist?(adapter_specific_schema_file)
+    load adapter_specific_schema_file
+  end
+ensure
+  $stdout = original_stdout
+end
+
+load_schema
+
+class SQLSubscriber
+  attr_reader :logged
+  attr_reader :payloads
+
+  def initialize
+    @logged = []
+    @payloads = []
+  end
+
+  def start(name, id, payload)
+    @payloads << payload
+    @logged << [payload[:sql].squish, payload[:name], payload[:binds]]
+  end
+
+  def finish(name, id, payload); end
+end
+
+module InTimeZone
+  private
+
+  def in_time_zone(zone)
+    old_zone  = Time.zone
+    old_tz    = ActiveRecord::Base.time_zone_aware_attributes
+
+    Time.zone = zone ? ActiveSupport::TimeZone[zone] : nil
+    ActiveRecord::Base.time_zone_aware_attributes = !zone.nil?
+    yield
+  ensure
+    Time.zone = old_zone
+    ActiveRecord::Base.time_zone_aware_attributes = old_tz
+  end
+end
+
+require 'mocha/setup' # FIXME: stop using mocha
diff --git a/activerecord/test/cases/hot_compatibility_test.rb b/activerecord/test/cases/hot_compatibility_test.rb
new file mode 100644
index 0000000000..b4617cf6f9
--- /dev/null
+++ b/activerecord/test/cases/hot_compatibility_test.rb
@@ -0,0 +1,54 @@
+require 'cases/helper'
+
+class HotCompatibilityTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  setup do
+    @klass = Class.new(ActiveRecord::Base) do
+      connection.create_table :hot_compatibilities, force: true do |t|
+        t.string :foo
+        t.string :bar
+      end
+
+      def self.name; 'HotCompatibility'; end
+    end
+  end
+
+  teardown do
+    ActiveRecord::Base.connection.drop_table :hot_compatibilities
+  end
+
+  test "insert after remove_column" do
+    # warm cache
+    @klass.create!
+
+    # we have 3 columns
+    assert_equal 3, @klass.columns.length
+
+    # remove one of them
+    @klass.connection.remove_column :hot_compatibilities, :bar
+
+    # we still have 3 columns in the cache
+    assert_equal 3, @klass.columns.length
+
+    # but we can successfully create a record so long as we don't
+    # reference the removed column
+    record = @klass.create! foo: 'foo'
+    record.reload
+    assert_equal 'foo', record.foo
+  end
+
+  test "update after remove_column" do
+    record = @klass.create! foo: 'foo'
+    assert_equal 3, @klass.columns.length
+    @klass.connection.remove_column :hot_compatibilities, :bar
+    assert_equal 3, @klass.columns.length
+
+    record.reload
+    assert_equal 'foo', record.foo
+    record.foo = 'bar'
+    record.save!
+    record.reload
+    assert_equal 'bar', record.foo
+  end
+end
diff --git a/activerecord/test/cases/i18n_test.rb b/activerecord/test/cases/i18n_test.rb
new file mode 100644
index 0000000000..a428f1d87b
--- /dev/null
+++ b/activerecord/test/cases/i18n_test.rb
@@ -0,0 +1,45 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/reply'
+
+class ActiveRecordI18nTests < ActiveRecord::TestCase
+
+  def setup
+    I18n.backend = I18n::Backend::Simple.new
+  end
+
+  def test_translated_model_attributes
+    I18n.backend.store_translations 'en', :activerecord => {:attributes => {:topic => {:title => 'topic title attribute'} } }
+    assert_equal 'topic title attribute', Topic.human_attribute_name('title')
+  end
+
+  def test_translated_model_attributes_with_symbols
+    I18n.backend.store_translations 'en', :activerecord => {:attributes => {:topic => {:title => 'topic title attribute'} } }
+    assert_equal 'topic title attribute', Topic.human_attribute_name(:title)
+  end
+
+  def test_translated_model_attributes_with_sti
+    I18n.backend.store_translations 'en', :activerecord => {:attributes => {:reply => {:title => 'reply title attribute'} } }
+    assert_equal 'reply title attribute', Reply.human_attribute_name('title')
+  end
+
+  def test_translated_model_attributes_with_sti_fallback
+    I18n.backend.store_translations 'en', :activerecord => {:attributes => {:topic => {:title => 'topic title attribute'} } }
+    assert_equal 'topic title attribute', Reply.human_attribute_name('title')
+  end
+
+  def test_translated_model_names
+    I18n.backend.store_translations 'en', :activerecord => {:models => {:topic => 'topic model'} }
+    assert_equal 'topic model', Topic.model_name.human
+  end
+
+  def test_translated_model_names_with_sti
+    I18n.backend.store_translations 'en', :activerecord => {:models => {:reply => 'reply model'} }
+    assert_equal 'reply model', Reply.model_name.human
+  end
+
+  def test_translated_model_names_with_sti_fallback
+    I18n.backend.store_translations 'en', :activerecord => {:models => {:topic => 'topic model'} }
+    assert_equal 'topic model', Reply.model_name.human
+  end
+end
diff --git a/activerecord/test/cases/inheritance_test.rb b/activerecord/test/cases/inheritance_test.rb
new file mode 100644
index 0000000000..792950d24d
--- /dev/null
+++ b/activerecord/test/cases/inheritance_test.rb
@@ -0,0 +1,369 @@
+require 'cases/helper'
+require 'models/company'
+require 'models/person'
+require 'models/post'
+require 'models/project'
+require 'models/subscriber'
+require 'models/vegetables'
+require 'models/shop'
+
+class InheritanceTest < ActiveRecord::TestCase
+  fixtures :companies, :projects, :subscribers, :accounts, :vegetables
+
+  def test_class_with_store_full_sti_class_returns_full_name
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+    assert_equal 'Namespaced::Company', Namespaced::Company.sti_name
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_class_with_blank_sti_name
+    company = Company.first
+    company = company.dup
+    company.extend(Module.new {
+      def read_attribute(name)
+        return '  ' if name == 'type'
+        super
+      end
+    })
+    company.save!
+    company = Company.all.to_a.find { |x| x.id == company.id }
+    assert_equal '  ', company.type
+  end
+
+  def test_class_without_store_full_sti_class_returns_demodulized_name
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = false
+    assert_equal 'Company', Namespaced::Company.sti_name
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_should_store_demodulized_class_name_with_store_full_sti_class_option_disabled
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = false
+    item = Namespaced::Company.new
+    assert_equal 'Company', item[:type]
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_should_store_full_class_name_with_store_full_sti_class_option_enabled
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+    item = Namespaced::Company.new
+    assert_equal 'Namespaced::Company', item[:type]
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_different_namespace_subclass_should_load_correctly_with_store_full_sti_class_option
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+    item = Namespaced::Company.create :name => "Wolverine 2"
+    assert_not_nil Company.find(item.id)
+    assert_not_nil Namespaced::Company.find(item.id)
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_company_descends_from_active_record
+    assert !ActiveRecord::Base.descends_from_active_record?
+    assert AbstractCompany.descends_from_active_record?, 'AbstractCompany should descend from ActiveRecord::Base'
+    assert Company.descends_from_active_record?, 'Company should descend from ActiveRecord::Base'
+    assert !Class.new(Company).descends_from_active_record?, 'Company subclass should not descend from ActiveRecord::Base'
+  end
+
+  def test_inheritance_base_class
+    assert_equal Post, Post.base_class
+    assert_equal Post, SpecialPost.base_class
+    assert_equal Post, StiPost.base_class
+    assert_equal SubStiPost, SubStiPost.base_class
+  end
+
+  def test_abstract_inheritance_base_class
+    assert_equal LoosePerson, LoosePerson.base_class
+    assert_equal LooseDescendant, LooseDescendant.base_class
+    assert_equal TightPerson, TightPerson.base_class
+    assert_equal TightPerson, TightDescendant.base_class
+  end
+
+  def test_base_class_activerecord_error
+    klass = Class.new { include ActiveRecord::Inheritance }
+    assert_raise(ActiveRecord::ActiveRecordError) { klass.base_class }
+  end
+
+  def test_a_bad_type_column
+    Company.connection.insert "INSERT INTO companies (id, #{QUOTED_TYPE}, name) VALUES(100, 'bad_class!', 'Not happening')"
+
+    assert_raise(ActiveRecord::SubclassNotFound) { Company.find(100) }
+  end
+
+  def test_inheritance_find
+    assert_kind_of Firm, Company.find(1), "37signals should be a firm"
+    assert_kind_of Firm, Firm.find(1), "37signals should be a firm"
+    assert_kind_of Client, Company.find(2), "Summit should be a client"
+    assert_kind_of Client, Client.find(2), "Summit should be a client"
+  end
+
+  def test_alt_inheritance_find
+    assert_kind_of Cucumber, Vegetable.find(1)
+    assert_kind_of Cucumber, Cucumber.find(1)
+    assert_kind_of Cabbage, Vegetable.find(2)
+    assert_kind_of Cabbage, Cabbage.find(2)
+  end
+
+  def test_alt_becomes_works_with_sti
+    vegetable = Vegetable.find(1)
+    assert_kind_of Vegetable, vegetable
+    cabbage = vegetable.becomes(Cabbage)
+    assert_kind_of Cabbage, cabbage
+  end
+
+  def test_alt_becomes_bang_resets_inheritance_type_column
+    vegetable = Vegetable.create!(name: "Red Pepper")
+    assert_nil vegetable.custom_type
+
+    cabbage = vegetable.becomes!(Cabbage)
+    assert_equal "Cabbage", cabbage.custom_type
+
+    vegetable = cabbage.becomes!(Vegetable)
+    assert_nil cabbage.custom_type
+  end
+
+  def test_inheritance_find_all
+    companies = Company.all.merge!(:order => 'id').to_a
+    assert_kind_of Firm, companies[0], "37signals should be a firm"
+    assert_kind_of Client, companies[1], "Summit should be a client"
+  end
+
+  def test_alt_inheritance_find_all
+    companies = Vegetable.all.merge!(:order => 'id').to_a
+    assert_kind_of Cucumber, companies[0]
+    assert_kind_of Cabbage, companies[1]
+  end
+
+  def test_inheritance_save
+    firm = Firm.new
+    firm.name = "Next Angle"
+    firm.save
+
+    next_angle = Company.find(firm.id)
+    assert_kind_of Firm, next_angle, "Next Angle should be a firm"
+  end
+
+  def test_alt_inheritance_save
+    cabbage = Cabbage.new(:name => 'Savoy')
+    cabbage.save!
+
+    savoy = Vegetable.find(cabbage.id)
+    assert_kind_of Cabbage, savoy
+  end
+
+  def test_inheritance_new_with_default_class
+    company = Company.new
+    assert_equal Company, company.class
+  end
+
+  def test_inheritance_new_with_base_class
+    company = Company.new(:type => 'Company')
+    assert_equal Company, company.class
+  end
+
+  def test_inheritance_new_with_subclass
+    firm = Company.new(:type => 'Firm')
+    assert_equal Firm, firm.class
+  end
+
+  def test_new_with_abstract_class
+    e = assert_raises(NotImplementedError) do
+      AbstractCompany.new
+    end
+    assert_equal("AbstractCompany is an abstract class and cannot be instantiated.", e.message)
+  end
+
+  def test_new_with_ar_base
+    e = assert_raises(NotImplementedError) do
+      ActiveRecord::Base.new
+    end
+    assert_equal("ActiveRecord::Base is an abstract class and cannot be instantiated.", e.message)
+  end
+
+  def test_new_with_invalid_type
+    assert_raise(ActiveRecord::SubclassNotFound) { Company.new(:type => 'InvalidType') }
+  end
+
+  def test_new_with_unrelated_type
+    assert_raise(ActiveRecord::SubclassNotFound) { Company.new(:type => 'Account') }
+  end
+
+  def test_new_with_complex_inheritance
+    assert_nothing_raised { Client.new(type: 'VerySpecialClient') }
+  end
+
+  def test_new_with_autoload_paths
+    path = File.expand_path('../../models/autoloadable', __FILE__)
+    ActiveSupport::Dependencies.autoload_paths << path
+
+    firm = Company.new(:type => 'ExtraFirm')
+    assert_equal ExtraFirm, firm.class
+  ensure
+    ActiveSupport::Dependencies.autoload_paths.reject! { |p| p == path }
+    ActiveSupport::Dependencies.clear
+  end
+
+  def test_inheritance_condition
+    assert_equal 11, Company.count
+    assert_equal 2, Firm.count
+    assert_equal 5, Client.count
+  end
+
+  def test_alt_inheritance_condition
+    assert_equal 4, Vegetable.count
+    assert_equal 1, Cucumber.count
+    assert_equal 3, Cabbage.count
+  end
+
+  def test_finding_incorrect_type_data
+    assert_raise(ActiveRecord::RecordNotFound) { Firm.find(2) }
+    assert_nothing_raised   { Firm.find(1) }
+  end
+
+  def test_alt_finding_incorrect_type_data
+    assert_raise(ActiveRecord::RecordNotFound) { Cucumber.find(2) }
+    assert_nothing_raised   { Cucumber.find(1) }
+  end
+
+  def test_update_all_within_inheritance
+    Client.update_all "name = 'I am a client'"
+    assert_equal "I am a client", Client.first.name
+    # Order by added as otherwise Oracle tests were failing because of different order of results
+    assert_equal "37signals", Firm.all.merge!(:order => "id").to_a.first.name
+  end
+
+  def test_alt_update_all_within_inheritance
+    Cabbage.update_all "name = 'the cabbage'"
+    assert_equal "the cabbage", Cabbage.first.name
+    assert_equal ["my cucumber"], Cucumber.all.map(&:name).uniq
+  end
+
+  def test_destroy_all_within_inheritance
+    Client.destroy_all
+    assert_equal 0, Client.count
+    assert_equal 2, Firm.count
+  end
+
+  def test_alt_destroy_all_within_inheritance
+    Cabbage.destroy_all
+    assert_equal 0, Cabbage.count
+    assert_equal 1, Cucumber.count
+  end
+
+  def test_find_first_within_inheritance
+    assert_kind_of Firm, Company.all.merge!(:where => "name = '37signals'").first
+    assert_kind_of Firm, Firm.all.merge!(:where => "name = '37signals'").first
+    assert_nil Client.all.merge!(:where => "name = '37signals'").first
+  end
+
+  def test_alt_find_first_within_inheritance
+    assert_kind_of Cabbage, Vegetable.all.merge!(:where => "name = 'his cabbage'").first
+    assert_kind_of Cabbage, Cabbage.all.merge!(:where => "name = 'his cabbage'").first
+    assert_nil Cucumber.all.merge!(:where => "name = 'his cabbage'").first
+  end
+
+  def test_complex_inheritance
+    very_special_client = VerySpecialClient.create("name" => "veryspecial")
+    assert_equal very_special_client, VerySpecialClient.where("name = 'veryspecial'").first
+    assert_equal very_special_client, SpecialClient.all.merge!(:where => "name = 'veryspecial'").first
+    assert_equal very_special_client, Company.all.merge!(:where => "name = 'veryspecial'").first
+    assert_equal very_special_client, Client.all.merge!(:where => "name = 'veryspecial'").first
+    assert_equal 1, Client.all.merge!(:where => "name = 'Summit'").to_a.size
+    assert_equal very_special_client, Client.find(very_special_client.id)
+  end
+
+  def test_alt_complex_inheritance
+    king_cole = KingCole.create("name" => "uniform heads")
+    assert_equal king_cole, KingCole.where("name = 'uniform heads'").first
+    assert_equal king_cole, GreenCabbage.all.merge!(:where => "name = 'uniform heads'").first
+    assert_equal king_cole, Cabbage.all.merge!(:where => "name = 'uniform heads'").first
+    assert_equal king_cole, Vegetable.all.merge!(:where => "name = 'uniform heads'").first
+    assert_equal 1, Cabbage.all.merge!(:where => "name = 'his cabbage'").to_a.size
+    assert_equal king_cole, Cabbage.find(king_cole.id)
+  end
+
+  def test_eager_load_belongs_to_something_inherited
+    account = Account.all.merge!(:includes => :firm).find(1)
+    assert account.association_cache.key?(:firm), "nil proves eager load failed"
+  end
+
+  def test_alt_eager_loading
+    cabbage = RedCabbage.all.merge!(:includes => :seller).find(4)
+    assert cabbage.association_cache.key?(:seller), "nil proves eager load failed"
+  end
+
+  def test_eager_load_belongs_to_primary_key_quoting
+    con = Account.connection
+    assert_sql(/#{con.quote_table_name('companies')}.#{con.quote_column_name('id')} IN \(1\)/) do
+      Account.all.merge!(:includes => :firm).find(1)
+    end
+  end
+
+  def test_inherits_custom_primary_key
+    assert_equal Subscriber.primary_key, SpecialSubscriber.primary_key
+  end
+
+  def test_inheritance_without_mapping
+    assert_kind_of SpecialSubscriber, SpecialSubscriber.find("webster132")
+    assert_nothing_raised { s = SpecialSubscriber.new("name" => "And breaaaaathe!"); s.id = 'roger'; s.save }
+  end
+
+  def test_scope_inherited_properly
+    assert_nothing_raised { Company.of_first_firm }
+    assert_nothing_raised { Client.of_first_firm }
+  end
+end
+
+class InheritanceComputeTypeTest < ActiveRecord::TestCase
+  fixtures :companies
+
+  def setup
+    ActiveSupport::Dependencies.log_activity = true
+  end
+
+  teardown do
+    ActiveSupport::Dependencies.log_activity = false
+    self.class.const_remove :FirmOnTheFly rescue nil
+    Firm.const_remove :FirmOnTheFly rescue nil
+  end
+
+  def test_instantiation_doesnt_try_to_require_corresponding_file
+    ActiveRecord::Base.store_full_sti_class = false
+    foo = Firm.first.clone
+    foo.type = 'FirmOnTheFly'
+    foo.save!
+
+    # Should fail without FirmOnTheFly in the type condition.
+    assert_raise(ActiveRecord::RecordNotFound) { Firm.find(foo.id) }
+
+    # Nest FirmOnTheFly in the test case where Dependencies won't see it.
+    self.class.const_set :FirmOnTheFly, Class.new(Firm)
+    assert_raise(ActiveRecord::SubclassNotFound) { Firm.find(foo.id) }
+
+    # Nest FirmOnTheFly in Firm where Dependencies will see it.
+    # This is analogous to nesting models in a migration.
+    Firm.const_set :FirmOnTheFly, Class.new(Firm)
+
+    # And instantiate will find the existing constant rather than trying
+    # to require firm_on_the_fly.
+    assert_nothing_raised { assert_kind_of Firm::FirmOnTheFly, Firm.find(foo.id) }
+  ensure
+    ActiveRecord::Base.store_full_sti_class = true
+  end
+
+  def test_sti_type_from_attributes_disabled_in_non_sti_class
+    phone = Shop::Product::Type.new(name: 'Phone')
+    product = Shop::Product.new(:type => phone)
+    assert product.save
+  end
+end
diff --git a/activerecord/test/cases/integration_test.rb b/activerecord/test/cases/integration_test.rb
new file mode 100644
index 0000000000..dfb8a608cb
--- /dev/null
+++ b/activerecord/test/cases/integration_test.rb
@@ -0,0 +1,138 @@
+# encoding: utf-8
+
+require 'cases/helper'
+require 'models/company'
+require 'models/developer'
+require 'models/owner'
+require 'models/pet'
+
+class IntegrationTest < ActiveRecord::TestCase
+  fixtures :companies, :developers, :owners, :pets
+
+  def test_to_param_should_return_string
+    assert_kind_of String, Client.first.to_param
+  end
+
+  def test_to_param_returns_nil_if_not_persisted
+    client = Client.new
+    assert_equal nil, client.to_param
+  end
+
+  def test_to_param_returns_id_if_not_persisted_but_id_is_set
+    client = Client.new
+    client.id = 1
+    assert_equal '1', client.to_param
+  end
+
+  def test_to_param_class_method
+    firm = Firm.find(4)
+    assert_equal '4-flamboyant-software', firm.to_param
+  end
+
+  def test_to_param_class_method_truncates
+    firm = Firm.find(4)
+    firm.name = 'a ' * 100
+    assert_equal '4-a-a-a-a-a-a-a-a-a', firm.to_param
+  end
+
+  def test_to_param_class_method_truncates_edge_case
+    firm = Firm.find(4)
+    firm.name = 'David HeinemeierHansson'
+    assert_equal '4-david', firm.to_param
+  end
+
+  def test_to_param_class_method_squishes
+    firm = Firm.find(4)
+    firm.name = "ab \n" * 100
+    assert_equal '4-ab-ab-ab-ab-ab-ab', firm.to_param
+  end
+
+  def test_to_param_class_method_multibyte_character
+    firm = Firm.find(4)
+    firm.name = "戦場ヶ原 ひたぎ"
+    assert_equal '4', firm.to_param
+  end
+
+  def test_to_param_class_method_uses_default_if_blank
+    firm = Firm.find(4)
+    firm.name = nil
+    assert_equal '4', firm.to_param
+    firm.name = ' '
+    assert_equal '4', firm.to_param
+  end
+
+  def test_to_param_class_method_uses_default_if_not_persisted
+    firm = Firm.new(name: 'Fancy Shirts')
+    assert_equal nil, firm.to_param
+  end
+
+  def test_to_param_with_no_arguments
+    assert_equal 'Firm', Firm.to_param
+  end
+
+  def test_cache_key_for_existing_record_is_not_timezone_dependent
+    utc_key = Developer.first.cache_key
+
+    with_timezone_config zone: "EST" do
+      est_key = Developer.first.cache_key
+      assert_equal utc_key, est_key
+    end
+  end
+
+  def test_cache_key_format_for_existing_record_with_updated_at
+    dev = Developer.first
+    assert_equal "developers/#{dev.id}-#{dev.updated_at.utc.to_s(:nsec)}", dev.cache_key
+  end
+
+  def test_cache_key_format_for_existing_record_with_updated_at_and_custom_cache_timestamp_format
+    dev = CachedDeveloper.first
+    assert_equal "cached_developers/#{dev.id}-#{dev.updated_at.utc.to_s(:number)}", dev.cache_key
+  end
+
+  def test_cache_key_changes_when_child_touched
+    owner = owners(:blackbeard)
+    pet   = pets(:parrot)
+
+    owner.update_column :updated_at, Time.current
+    key = owner.cache_key
+
+    assert pet.touch
+    assert_not_equal key, owner.reload.cache_key
+  end
+
+  def test_cache_key_format_for_existing_record_with_nil_updated_timestamps
+    dev = Developer.first
+    dev.update_columns(updated_at: nil, updated_on: nil)
+    assert_match(/\/#{dev.id}$/, dev.cache_key)
+  end
+
+  def test_cache_key_for_updated_on
+    dev = Developer.first
+    dev.updated_at = nil
+    assert_equal "developers/#{dev.id}-#{dev.updated_on.utc.to_s(:nsec)}", dev.cache_key
+  end
+
+  def test_cache_key_for_newer_updated_at
+    dev = Developer.first
+    dev.updated_at += 3600
+    assert_equal "developers/#{dev.id}-#{dev.updated_at.utc.to_s(:nsec)}", dev.cache_key
+  end
+
+  def test_cache_key_for_newer_updated_on
+    dev = Developer.first
+    dev.updated_on += 3600
+    assert_equal "developers/#{dev.id}-#{dev.updated_on.utc.to_s(:nsec)}", dev.cache_key
+  end
+
+  def test_cache_key_format_is_precise_enough
+    dev = Developer.first
+    key = dev.cache_key
+    dev.touch
+    assert_not_equal key, dev.cache_key
+  end
+
+  def test_named_timestamps_for_cache_key
+    owner = owners(:blackbeard)
+    assert_equal "owners/#{owner.id}-#{owner.happy_at.utc.to_s(:nsec)}", owner.cache_key(:updated_at, :happy_at)
+  end
+end
diff --git a/activerecord/test/cases/invalid_connection_test.rb b/activerecord/test/cases/invalid_connection_test.rb
new file mode 100644
index 0000000000..8416c81f45
--- /dev/null
+++ b/activerecord/test/cases/invalid_connection_test.rb
@@ -0,0 +1,22 @@
+require "cases/helper"
+
+class TestAdapterWithInvalidConnection < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  class Bird < ActiveRecord::Base
+  end
+
+  def setup
+    # Can't just use current adapter; sqlite3 will create a database
+    # file on the fly.
+    Bird.establish_connection adapter: 'mysql', database: 'i_do_not_exist'
+  end
+
+  teardown do
+    Bird.remove_connection
+  end
+
+  test "inspect on Model class does not raise" do
+    assert_equal "#{Bird.name} (call '#{Bird.name}.connection' to establish a connection)", Bird.inspect
+  end
+end
diff --git a/activerecord/test/cases/invalid_date_test.rb b/activerecord/test/cases/invalid_date_test.rb
new file mode 100644
index 0000000000..426a350379
--- /dev/null
+++ b/activerecord/test/cases/invalid_date_test.rb
@@ -0,0 +1,32 @@
+require 'cases/helper'
+require 'models/topic'
+
+class InvalidDateTest < ActiveRecord::TestCase
+  def test_assign_valid_dates
+    valid_dates = [[2007, 11, 30], [1993, 2, 28], [2008, 2, 29]]
+
+    invalid_dates = [[2007, 11, 31], [1993, 2, 29], [2007, 2, 29]]
+
+    valid_dates.each do |date_src|
+      topic = Topic.new("last_read(1i)" => date_src[0].to_s, "last_read(2i)" => date_src[1].to_s, "last_read(3i)" => date_src[2].to_s)
+      # Oracle DATE columns are datetime columns and Oracle adapter returns Time value
+      if current_adapter?(:OracleAdapter)
+        assert_equal(topic.last_read.to_date, Date.new(*date_src))
+      else
+        assert_equal(topic.last_read, Date.new(*date_src))
+      end
+    end
+
+    invalid_dates.each do |date_src|
+      assert_nothing_raised do
+        topic = Topic.new({"last_read(1i)" => date_src[0].to_s, "last_read(2i)" => date_src[1].to_s, "last_read(3i)" => date_src[2].to_s})
+        # Oracle DATE columns are datetime columns and Oracle adapter returns Time value
+        if current_adapter?(:OracleAdapter)
+          assert_equal(topic.last_read.to_date, Time.local(*date_src).to_date, "The date should be modified according to the behavior of the Time object")
+        else
+          assert_equal(topic.last_read, Time.local(*date_src).to_date, "The date should be modified according to the behavior of the Time object")
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/invertible_migration_test.rb b/activerecord/test/cases/invertible_migration_test.rb
new file mode 100644
index 0000000000..285172d33e
--- /dev/null
+++ b/activerecord/test/cases/invertible_migration_test.rb
@@ -0,0 +1,290 @@
+require "cases/helper"
+
+module ActiveRecord
+  class InvertibleMigrationTest < ActiveRecord::TestCase
+    class SilentMigration < ActiveRecord::Migration
+      def write(text = '')
+        # sssshhhhh!!
+      end
+    end
+
+    class InvertibleMigration < SilentMigration
+      def change
+        create_table("horses") do |t|
+          t.column :content, :text
+          t.column :remind_at, :datetime
+        end
+      end
+    end
+
+    class InvertibleRevertMigration < SilentMigration
+      def change
+        revert do
+          create_table("horses") do |t|
+            t.column :content, :text
+            t.column :remind_at, :datetime
+          end
+        end
+      end
+    end
+
+    class InvertibleByPartsMigration < SilentMigration
+      attr_writer :test
+      def change
+        create_table("new_horses") do |t|
+          t.column :breed, :string
+        end
+        reversible do |dir|
+          @test.yield :both
+          dir.up    { @test.yield :up }
+          dir.down  { @test.yield :down }
+        end
+        revert do
+          create_table("horses") do |t|
+            t.column :content, :text
+            t.column :remind_at, :datetime
+          end
+        end
+      end
+    end
+
+    class NonInvertibleMigration < SilentMigration
+      def change
+        create_table("horses") do |t|
+          t.column :content, :text
+          t.column :remind_at, :datetime
+        end
+        remove_column "horses", :content
+      end
+    end
+
+    class RemoveIndexMigration1 < SilentMigration
+      def self.up
+        create_table("horses") do |t|
+          t.column :name, :string
+          t.column :color, :string
+          t.index [:name, :color]
+        end
+      end
+    end
+
+    class RemoveIndexMigration2 < SilentMigration
+      def change
+        change_table("horses") do |t|
+          t.remove_index [:name, :color]
+        end
+      end
+    end
+
+    class LegacyMigration < ActiveRecord::Migration
+      def self.up
+        create_table("horses") do |t|
+          t.column :content, :text
+          t.column :remind_at, :datetime
+        end
+      end
+
+      def self.down
+        drop_table("horses")
+      end
+    end
+
+    class RevertWholeMigration < SilentMigration
+      def initialize(name = self.class.name, version = nil, migration)
+        @migration = migration
+        super(name, version)
+      end
+
+      def change
+        revert @migration
+      end
+    end
+
+    class NestedRevertWholeMigration < RevertWholeMigration
+      def change
+        revert { super }
+      end
+    end
+
+    class RevertNamedIndexMigration1 < SilentMigration
+      def change
+        create_table("horses") do |t|
+          t.column :content, :string
+          t.column :remind_at, :datetime
+        end
+        add_index :horses, :content
+      end
+    end
+
+    class RevertNamedIndexMigration2 < SilentMigration
+      def change
+        add_index :horses, :content, name: "horses_index_named"
+      end
+    end
+
+    teardown do
+      %w[horses new_horses].each do |table|
+        if ActiveRecord::Base.connection.table_exists?(table)
+          ActiveRecord::Base.connection.drop_table(table)
+        end
+      end
+    end
+
+    def test_no_reverse
+      migration = NonInvertibleMigration.new
+      migration.migrate(:up)
+      assert_raises(IrreversibleMigration) do
+        migration.migrate(:down)
+      end
+    end
+
+    def test_exception_on_removing_index_without_column_option
+      RemoveIndexMigration1.new.migrate(:up)
+      migration = RemoveIndexMigration2.new
+      migration.migrate(:up)
+
+      assert_raises(IrreversibleMigration) do
+        migration.migrate(:down)
+      end
+    end
+
+    def test_migrate_up
+      migration = InvertibleMigration.new
+      migration.migrate(:up)
+      assert migration.connection.table_exists?("horses"), "horses should exist"
+    end
+
+    def test_migrate_down
+      migration = InvertibleMigration.new
+      migration.migrate :up
+      migration.migrate :down
+      assert !migration.connection.table_exists?("horses")
+    end
+
+    def test_migrate_revert
+      migration = InvertibleMigration.new
+      revert = InvertibleRevertMigration.new
+      migration.migrate :up
+      revert.migrate :up
+      assert !migration.connection.table_exists?("horses")
+      revert.migrate :down
+      assert migration.connection.table_exists?("horses")
+      migration.migrate :down
+      assert !migration.connection.table_exists?("horses")
+    end
+
+    def test_migrate_revert_by_part
+      InvertibleMigration.new.migrate :up
+      received = []
+      migration = InvertibleByPartsMigration.new
+      migration.test = ->(dir){
+        assert migration.connection.table_exists?("horses")
+        assert migration.connection.table_exists?("new_horses")
+        received << dir
+      }
+      migration.migrate :up
+      assert_equal [:both, :up], received
+      assert !migration.connection.table_exists?("horses")
+      assert migration.connection.table_exists?("new_horses")
+      migration.migrate :down
+      assert_equal [:both, :up, :both, :down], received
+      assert migration.connection.table_exists?("horses")
+      assert !migration.connection.table_exists?("new_horses")
+    end
+
+    def test_migrate_revert_whole_migration
+      migration = InvertibleMigration.new
+      [LegacyMigration, InvertibleMigration].each do |klass|
+        revert = RevertWholeMigration.new(klass)
+        migration.migrate :up
+        revert.migrate :up
+        assert !migration.connection.table_exists?("horses")
+        revert.migrate :down
+        assert migration.connection.table_exists?("horses")
+        migration.migrate :down
+        assert !migration.connection.table_exists?("horses")
+      end
+    end
+
+    def test_migrate_nested_revert_whole_migration
+      revert = NestedRevertWholeMigration.new(InvertibleRevertMigration)
+      revert.migrate :down
+      assert revert.connection.table_exists?("horses")
+      revert.migrate :up
+      assert !revert.connection.table_exists?("horses")
+    end
+
+    def test_revert_order
+      block = Proc.new{|t| t.string :name }
+      recorder = ActiveRecord::Migration::CommandRecorder.new(ActiveRecord::Base.connection)
+      recorder.instance_eval do
+        create_table("apples", &block)
+        revert do
+          create_table("bananas", &block)
+          revert do
+            create_table("clementines")
+            create_table("dates")
+          end
+          create_table("elderberries")
+        end
+        revert do
+          create_table("figs")
+          create_table("grapes")
+        end
+      end
+      assert_equal [[:create_table, ["apples"], block], [:drop_table, ["elderberries"], nil],
+                    [:create_table, ["clementines"], nil], [:create_table, ["dates"], nil],
+                    [:drop_table, ["bananas"], block], [:drop_table, ["grapes"], nil],
+                    [:drop_table, ["figs"], nil]], recorder.commands
+    end
+
+    def test_legacy_up
+      LegacyMigration.migrate :up
+      assert ActiveRecord::Base.connection.table_exists?("horses"), "horses should exist"
+    end
+
+    def test_legacy_down
+      LegacyMigration.migrate :up
+      LegacyMigration.migrate :down
+      assert !ActiveRecord::Base.connection.table_exists?("horses"), "horses should not exist"
+    end
+
+    def test_up
+      LegacyMigration.up
+      assert ActiveRecord::Base.connection.table_exists?("horses"), "horses should exist"
+    end
+
+    def test_down
+      LegacyMigration.up
+      LegacyMigration.down
+      assert !ActiveRecord::Base.connection.table_exists?("horses"), "horses should not exist"
+    end
+
+    def test_migrate_down_with_table_name_prefix
+      ActiveRecord::Base.table_name_prefix = 'p_'
+      ActiveRecord::Base.table_name_suffix = '_s'
+      migration = InvertibleMigration.new
+      migration.migrate(:up)
+      assert_nothing_raised { migration.migrate(:down) }
+      assert !ActiveRecord::Base.connection.table_exists?("p_horses_s"), "p_horses_s should not exist"
+    ensure
+      ActiveRecord::Base.table_name_prefix = ActiveRecord::Base.table_name_suffix = ''
+    end
+
+    # MySQL 5.7 and Oracle do not allow to create duplicate indexes on the same columns
+    unless current_adapter?(:MysqlAdapter, :Mysql2Adapter, :OracleAdapter)
+      def test_migrate_revert_add_index_with_name
+        RevertNamedIndexMigration1.new.migrate(:up)
+        RevertNamedIndexMigration2.new.migrate(:up)
+        RevertNamedIndexMigration2.new.migrate(:down)
+
+        connection = ActiveRecord::Base.connection
+        assert connection.index_exists?(:horses, :content),
+               "index on content should exist"
+        assert !connection.index_exists?(:horses, :content, name: "horses_index_named"),
+              "horses_index_named index should not exist"
+      end
+    end
+
+  end
+end
diff --git a/activerecord/test/cases/json_serialization_test.rb b/activerecord/test/cases/json_serialization_test.rb
new file mode 100644
index 0000000000..a222675918
--- /dev/null
+++ b/activerecord/test/cases/json_serialization_test.rb
@@ -0,0 +1,300 @@
+require "cases/helper"
+require 'models/contact'
+require 'models/post'
+require 'models/author'
+require 'models/tagging'
+require 'models/tag'
+require 'models/comment'
+
+module JsonSerializationHelpers
+  private
+
+  def set_include_root_in_json(value)
+    original_root_in_json = ActiveRecord::Base.include_root_in_json
+    ActiveRecord::Base.include_root_in_json = value
+    yield
+  ensure
+    ActiveRecord::Base.include_root_in_json = original_root_in_json
+  end
+end
+
+class JsonSerializationTest < ActiveRecord::TestCase
+  include JsonSerializationHelpers
+
+  class NamespacedContact < Contact
+    column :name, :string
+  end
+
+  def setup
+    @contact = Contact.new(
+      :name        => 'Konata Izumi',
+      :age         => 16,
+      :avatar      => 'binarydata',
+      :created_at  => Time.utc(2006, 8, 1),
+      :awesome     => true,
+      :preferences => { :shows => 'anime' }
+    )
+  end
+
+  def test_should_demodulize_root_in_json
+    set_include_root_in_json(true) do
+      @contact = NamespacedContact.new name: 'whatever'
+      json = @contact.to_json
+      assert_match %r{^\{"namespaced_contact":\{}, json
+    end
+  end
+
+  def test_should_include_root_in_json
+    set_include_root_in_json(true) do
+      json = @contact.to_json
+
+      assert_match %r{^\{"contact":\{}, json
+      assert_match %r{"name":"Konata Izumi"}, json
+      assert_match %r{"age":16}, json
+      assert json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
+      assert_match %r{"awesome":true}, json
+      assert_match %r{"preferences":\{"shows":"anime"\}}, json
+    end
+  end
+
+  def test_should_encode_all_encodable_attributes
+    json = @contact.to_json
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
+    assert_match %r{"awesome":true}, json
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  def test_should_allow_attribute_filtering_with_only
+    json = @contact.to_json(:only => [:name, :age])
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert_no_match %r{"awesome":true}, json
+    assert !json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
+    assert_no_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  def test_should_allow_attribute_filtering_with_except
+    json = @contact.to_json(:except => [:name, :age])
+
+    assert_no_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{"age":16}, json
+    assert_match %r{"awesome":true}, json
+    assert json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  def test_methods_are_called_on_object
+    # Define methods on fixture.
+    def @contact.label; "Has cheezburger"; end
+    def @contact.favorite_quote; "Constraints are liberating"; end
+
+    # Single method.
+    assert_match %r{"label":"Has cheezburger"}, @contact.to_json(:only => :name, :methods => :label)
+
+    # Both methods.
+    methods_json = @contact.to_json(:only => :name, :methods => [:label, :favorite_quote])
+    assert_match %r{"label":"Has cheezburger"}, methods_json
+    assert_match %r{"favorite_quote":"Constraints are liberating"}, methods_json
+  end
+
+  def test_uses_serializable_hash_with_only_option
+    def @contact.serializable_hash(options=nil)
+      super(only: %w(name))
+    end
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{awesome}, json
+    assert_no_match %r{age}, json
+  end
+
+  def test_uses_serializable_hash_with_except_option
+    def @contact.serializable_hash(options=nil)
+      super(except: %w(age))
+    end
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"awesome":true}, json
+    assert_no_match %r{age}, json
+  end
+
+  def test_does_not_include_inheritance_column_from_sti
+    @contact = ContactSti.new(@contact.attributes)
+    assert_equal 'ContactSti', @contact.type
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{type}, json
+    assert_no_match %r{ContactSti}, json
+  end
+
+  def test_serializable_hash_with_default_except_option_and_excluding_inheritance_column_from_sti
+    @contact = ContactSti.new(@contact.attributes)
+    assert_equal 'ContactSti', @contact.type
+
+    def @contact.serializable_hash(options={})
+      super({ except: %w(age) }.merge!(options))
+    end
+
+    json = @contact.to_json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{age}, json
+    assert_no_match %r{type}, json
+    assert_no_match %r{ContactSti}, json
+  end
+
+  def test_serializable_hash_should_not_modify_options_in_argument
+    options = { :only => :name }
+    @contact.serializable_hash(options)
+
+    assert_nil options[:except]
+  end
+end
+
+class DatabaseConnectedJsonEncodingTest < ActiveRecord::TestCase
+  fixtures :authors, :posts, :comments, :tags, :taggings
+
+  include JsonSerializationHelpers
+
+  def setup
+    @david = authors(:david)
+    @mary = authors(:mary)
+  end
+
+  def test_includes_uses_association_name
+    json = @david.to_json(:include => :posts)
+
+    assert_match %r{"posts":\[}, json
+
+    assert_match %r{"id":1}, json
+    assert_match %r{"name":"David"}, json
+
+    assert_match %r{"author_id":1}, json
+    assert_match %r{"title":"Welcome to the weblog"}, json
+    assert_match %r{"body":"Such a lovely day"}, json
+
+    assert_match %r{"title":"So I was thinking"}, json
+    assert_match %r{"body":"Like I hopefully always am"}, json
+  end
+
+  def test_includes_uses_association_name_and_applies_attribute_filters
+    json = @david.to_json(:include => { :posts => { :only => :title } })
+
+    assert_match %r{"name":"David"}, json
+    assert_match %r{"posts":\[}, json
+
+    assert_match %r{"title":"Welcome to the weblog"}, json
+    assert_no_match %r{"body":"Such a lovely day"}, json
+
+    assert_match %r{"title":"So I was thinking"}, json
+    assert_no_match %r{"body":"Like I hopefully always am"}, json
+  end
+
+  def test_includes_fetches_second_level_associations
+    json = @david.to_json(:include => { :posts => { :include => { :comments => { :only => :body } } } })
+
+    assert_match %r{"name":"David"}, json
+    assert_match %r{"posts":\[}, json
+
+    assert_match %r{"comments":\[}, json
+    assert_match %r{\{"body":"Thank you again for the welcome"\}}, json
+    assert_match %r{\{"body":"Don't think too hard"\}}, json
+    assert_no_match %r{"post_id":}, json
+  end
+
+  def test_includes_fetches_nth_level_associations
+    json = @david.to_json(
+      :include => {
+        :posts => {
+          :include => {
+            :taggings => {
+              :include => {
+                :tag => { :only => :name }
+              }
+            }
+          }
+        }
+    })
+
+    assert_match %r{"name":"David"}, json
+    assert_match %r{"posts":\[}, json
+
+    assert_match %r{"taggings":\[}, json
+    assert_match %r{"tag":\{"name":"General"\}}, json
+  end
+
+  def test_includes_doesnt_merge_opts_from_base
+    json = @david.to_json(
+      :only => :id,
+      :include => :posts
+    )
+
+    assert_match %{"title":"Welcome to the weblog"}, json
+  end
+
+  def test_should_not_call_methods_on_associations_that_dont_respond
+    def @david.favorite_quote; "Constraints are liberating"; end
+    json = @david.to_json(:include => :posts, :methods => :favorite_quote)
+
+    assert !@david.posts.first.respond_to?(:favorite_quote)
+    assert_match %r{"favorite_quote":"Constraints are liberating"}, json
+    assert_equal %r{"favorite_quote":}.match(json).size, 1
+  end
+
+  def test_should_allow_only_option_for_list_of_authors
+    set_include_root_in_json(false) do
+      authors = [@david, @mary]
+      assert_equal %([{"name":"David"},{"name":"Mary"}]), ActiveSupport::JSON.encode(authors, only: :name)
+    end
+  end
+
+  def test_should_allow_except_option_for_list_of_authors
+    set_include_root_in_json(false) do
+      authors = [@david, @mary]
+      encoded = ActiveSupport::JSON.encode(authors, except: [
+        :name, :author_address_id, :author_address_extra_id,
+        :organization_id, :owned_essay_id
+      ])
+      assert_equal %([{"id":1},{"id":2}]), encoded
+    end
+  end
+
+  def test_should_allow_includes_for_list_of_authors
+    authors = [@david, @mary]
+    json = ActiveSupport::JSON.encode(authors,
+      :only => :name,
+      :include => {
+        :posts => { :only => :id }
+      }
+    )
+
+    ['"name":"David"', '"posts":[', '{"id":1}', '{"id":2}', '{"id":4}',
+     '{"id":5}', '{"id":6}', '"name":"Mary"', '"posts":[', '{"id":7}', '{"id":9}'].each do |fragment|
+      assert json.include?(fragment), json
+     end
+  end
+
+  def test_should_allow_options_for_hash_of_authors
+    set_include_root_in_json(true) do
+      authors_hash = {
+        1 => @david,
+        2 => @mary
+      }
+      assert_equal %({"1":{"author":{"name":"David"}}}), ActiveSupport::JSON.encode(authors_hash, only: [1, :name])
+    end
+  end
+
+  def test_should_be_able_to_encode_relation
+    set_include_root_in_json(true) do
+      authors_relation = Author.where(id: [@david.id, @mary.id])
+
+      json = ActiveSupport::JSON.encode authors_relation, only: :name
+      assert_equal '[{"author":{"name":"David"}},{"author":{"name":"Mary"}}]', json
+    end
+  end
+end
diff --git a/activerecord/test/cases/locking_test.rb b/activerecord/test/cases/locking_test.rb
new file mode 100644
index 0000000000..0c9dff2c25
--- /dev/null
+++ b/activerecord/test/cases/locking_test.rb
@@ -0,0 +1,482 @@
+require 'thread'
+require "cases/helper"
+require 'models/person'
+require 'models/job'
+require 'models/reader'
+require 'models/ship'
+require 'models/legacy_thing'
+require 'models/reference'
+require 'models/string_key_object'
+require 'models/car'
+require 'models/bulb'
+require 'models/engine'
+require 'models/wheel'
+require 'models/treasure'
+
+class LockWithoutDefault < ActiveRecord::Base; end
+
+class LockWithCustomColumnWithoutDefault < ActiveRecord::Base
+  self.table_name = :lock_without_defaults_cust
+  self.column_defaults # to test @column_defaults caching.
+  self.locking_column = :custom_lock_version
+end
+
+class ReadonlyNameShip < Ship
+  attr_readonly :name
+end
+
+class OptimisticLockingTest < ActiveRecord::TestCase
+  fixtures :people, :legacy_things, :references, :string_key_objects, :peoples_treasures
+
+  def test_quote_value_passed_lock_col
+    p1 = Person.find(1)
+    assert_equal 0, p1.lock_version
+
+    Person.expects(:quote_value).with(0, Person.columns_hash[Person.locking_column]).returns('0').once
+
+    p1.first_name = 'anika2'
+    p1.save!
+
+    assert_equal 1, p1.lock_version
+  end
+
+  def test_non_integer_lock_existing
+    s1 = StringKeyObject.find("record1")
+    s2 = StringKeyObject.find("record1")
+    assert_equal 0, s1.lock_version
+    assert_equal 0, s2.lock_version
+
+    s1.name = 'updated record'
+    s1.save!
+    assert_equal 1, s1.lock_version
+    assert_equal 0, s2.lock_version
+
+    s2.name = 'doubly updated record'
+    assert_raise(ActiveRecord::StaleObjectError) { s2.save! }
+  end
+
+  def test_non_integer_lock_destroy
+    s1 = StringKeyObject.find("record1")
+    s2 = StringKeyObject.find("record1")
+    assert_equal 0, s1.lock_version
+    assert_equal 0, s2.lock_version
+
+    s1.name = 'updated record'
+    s1.save!
+    assert_equal 1, s1.lock_version
+    assert_equal 0, s2.lock_version
+    assert_raise(ActiveRecord::StaleObjectError) { s2.destroy }
+
+    assert s1.destroy
+    assert s1.frozen?
+    assert s1.destroyed?
+    assert_raises(ActiveRecord::RecordNotFound) { StringKeyObject.find("record1") }
+  end
+
+  def test_lock_existing
+    p1 = Person.find(1)
+    p2 = Person.find(1)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = 'stu'
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p2.first_name = 'sue'
+    assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+  end
+
+  # See Lighthouse ticket #1966
+  def test_lock_destroy
+    p1 = Person.find(1)
+    p2 = Person.find(1)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = 'stu'
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    assert_raises(ActiveRecord::StaleObjectError) { p2.destroy }
+
+    assert p1.destroy
+    assert p1.frozen?
+    assert p1.destroyed?
+    assert_raises(ActiveRecord::RecordNotFound) { Person.find(1) }
+  end
+
+  def test_lock_repeating
+    p1 = Person.find(1)
+    p2 = Person.find(1)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = 'stu'
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p2.first_name = 'sue'
+    assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+    p2.first_name = 'sue2'
+    assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+  end
+
+  def test_lock_new
+    p1 = Person.new(:first_name => 'anika')
+    assert_equal 0, p1.lock_version
+
+    p1.first_name = 'anika2'
+    p1.save!
+    p2 = Person.find(p1.id)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = 'anika3'
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p2.first_name = 'sue'
+    assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+  end
+
+  def test_lock_exception_record
+    p1 = Person.new(:first_name => 'mira')
+    assert_equal 0, p1.lock_version
+
+    p1.first_name = 'mira2'
+    p1.save!
+    p2 = Person.find(p1.id)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = 'mira3'
+    p1.save!
+
+    p2.first_name = 'sue'
+    error = assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+    assert_equal(error.record.object_id, p2.object_id)
+  end
+
+  def test_lock_new_with_nil
+    p1 = Person.new(:first_name => 'anika')
+    p1.save!
+    p1.lock_version = nil # simulate bad fixture or column with no default
+    p1.save!
+    assert_equal 1, p1.lock_version
+  end
+
+  def test_touch_existing_lock
+    p1 = Person.find(1)
+    assert_equal 0, p1.lock_version
+
+    p1.touch
+    assert_equal 1, p1.lock_version
+  end
+
+  def test_lock_column_name_existing
+    t1 = LegacyThing.find(1)
+    t2 = LegacyThing.find(1)
+    assert_equal 0, t1.version
+    assert_equal 0, t2.version
+
+    t1.tps_report_number = 700
+    t1.save!
+    assert_equal 1, t1.version
+    assert_equal 0, t2.version
+
+    t2.tps_report_number = 800
+    assert_raise(ActiveRecord::StaleObjectError) { t2.save! }
+  end
+
+  def test_lock_column_is_mass_assignable
+    p1 = Person.create(:first_name => 'bianca')
+    assert_equal 0, p1.lock_version
+    assert_equal p1.lock_version, Person.new(p1.attributes).lock_version
+
+    p1.first_name = 'bianca2'
+    p1.save!
+    assert_equal 1, p1.lock_version
+    assert_equal p1.lock_version, Person.new(p1.attributes).lock_version
+  end
+
+  def test_lock_without_default_sets_version_to_zero
+    t1 = LockWithoutDefault.new
+    assert_equal 0, t1.lock_version
+
+    t1.save
+    t1 = LockWithoutDefault.find(t1.id)
+    assert_equal 0, t1.lock_version
+  end
+
+  def test_lock_with_custom_column_without_default_sets_version_to_zero
+    t1 = LockWithCustomColumnWithoutDefault.new
+    assert_equal 0, t1.custom_lock_version
+
+    t1.save
+    t1 = LockWithCustomColumnWithoutDefault.find(t1.id)
+    assert_equal 0, t1.custom_lock_version
+  end
+
+  def test_readonly_attributes
+    assert_equal Set.new([ 'name' ]), ReadonlyNameShip.readonly_attributes
+
+    s = ReadonlyNameShip.create(:name => "unchangeable name")
+    s.reload
+    assert_equal "unchangeable name", s.name
+
+    s.update(name: "changed name")
+    s.reload
+    assert_equal "unchangeable name", s.name
+  end
+
+  def test_quote_table_name
+    ref = references(:michael_magician)
+    ref.favourite = !ref.favourite
+    assert ref.save
+  end
+
+  # Useful for partial updates, don't only update the lock_version if there
+  # is nothing else being updated.
+  def test_update_without_attributes_does_not_only_update_lock_version
+    assert_nothing_raised do
+      p1 = Person.create!(:first_name => 'anika')
+      lock_version = p1.lock_version
+      p1.save
+      p1.reload
+      assert_equal lock_version, p1.lock_version
+    end
+  end
+
+  def test_polymorphic_destroy_with_dependencies_and_lock_version
+    car = Car.create!
+
+    assert_difference 'car.wheels.count'  do
+      car.wheels << Wheel.create!
+    end
+    assert_difference 'car.wheels.count', -1  do
+      car.destroy
+    end
+    assert car.destroyed?
+  end
+
+  def test_removing_has_and_belongs_to_many_associations_upon_destroy
+    p = RichPerson.create! first_name: 'Jon'
+    p.treasures.create!
+    assert !p.treasures.empty?
+    p.destroy
+    assert p.treasures.empty?
+    assert RichPerson.connection.select_all("SELECT * FROM peoples_treasures WHERE rich_person_id = 1").empty?
+  end
+
+  def test_yaml_dumping_with_lock_column
+    t1 = LockWithoutDefault.new
+    t2 = YAML.load(YAML.dump(t1))
+
+    assert_equal t1.attributes, t2.attributes
+  end
+end
+
+class OptimisticLockingWithSchemaChangeTest < ActiveRecord::TestCase
+  fixtures :people, :legacy_things, :references
+
+  # need to disable transactional fixtures, because otherwise the sqlite3
+  # adapter (at least) chokes when we try and change the schema in the middle
+  # of a test (see test_increment_counter_*).
+  self.use_transactional_fixtures = false
+
+  { :lock_version => Person, :custom_lock_version => LegacyThing }.each do |name, model|
+    define_method("test_increment_counter_updates_#{name}") do
+      counter_test model, 1 do |id|
+        model.increment_counter :test_count, id
+      end
+    end
+
+    define_method("test_decrement_counter_updates_#{name}") do
+      counter_test model, -1 do |id|
+        model.decrement_counter :test_count, id
+      end
+    end
+
+    define_method("test_update_counters_updates_#{name}") do
+      counter_test model, 1 do |id|
+        model.update_counters id, :test_count => 1
+      end
+    end
+  end
+
+  # See Lighthouse ticket #1966
+  def test_destroy_dependents
+    # Establish dependent relationship between People and LegacyThing
+    add_counter_column_to(Person, 'legacy_things_count')
+    LegacyThing.connection.add_column LegacyThing.table_name, 'person_id', :integer
+    LegacyThing.reset_column_information
+    LegacyThing.class_eval do
+      belongs_to :person, :counter_cache => true
+    end
+    Person.class_eval do
+      has_many :legacy_things, :dependent => :destroy
+    end
+
+    # Make sure that counter incrementing doesn't cause problems
+    p1 = Person.new(:first_name => 'fjord')
+    p1.save!
+    t = LegacyThing.new(:person => p1)
+    t.save!
+    p1.reload
+    assert_equal 1, p1.legacy_things_count
+    assert p1.destroy
+    assert_equal true, p1.frozen?
+    assert_raises(ActiveRecord::RecordNotFound) { Person.find(p1.id) }
+    assert_raises(ActiveRecord::RecordNotFound) { LegacyThing.find(t.id) }
+  ensure
+    remove_counter_column_from(Person, 'legacy_things_count')
+  end
+
+  private
+
+    def add_counter_column_to(model, col='test_count')
+      model.connection.add_column model.table_name, col, :integer, :null => false, :default => 0
+      model.reset_column_information
+    end
+
+    def remove_counter_column_from(model, col = :test_count)
+      model.connection.remove_column model.table_name, col
+      model.reset_column_information
+    end
+
+    def counter_test(model, expected_count)
+      add_counter_column_to(model)
+      object = model.first
+      assert_equal 0, object.test_count
+      assert_equal 0, object.send(model.locking_column)
+      yield object.id
+      object.reload
+      assert_equal expected_count, object.test_count
+      assert_equal 1, object.send(model.locking_column)
+    ensure
+      remove_counter_column_from(model)
+    end
+end
+
+
+# TODO: test against the generated SQL since testing locking behavior itself
+# is so cumbersome. Will deadlock Ruby threads if the underlying db.execute
+# blocks, so separate script called by Kernel#system is needed.
+# (See exec vs. async_exec in the PostgreSQL adapter.)
+unless in_memory_db?
+  class PessimisticLockingTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+    fixtures :people, :readers
+
+    def setup
+      Person.connection_pool.clear_reloadable_connections!
+      # Avoid introspection queries during tests.
+      Person.columns; Reader.columns
+    end
+
+    # Test typical find.
+    def test_sane_find_with_lock
+      assert_nothing_raised do
+        Person.transaction do
+          Person.lock.find(1)
+        end
+      end
+    end
+
+    # PostgreSQL protests SELECT ... FOR UPDATE on an outer join.
+    unless current_adapter?(:PostgreSQLAdapter)
+      # Test locked eager find.
+      def test_eager_find_with_lock
+        assert_nothing_raised do
+          Person.transaction do
+            Person.includes(:readers).lock.find(1)
+          end
+        end
+      end
+    end
+
+    # Locking a record reloads it.
+    def test_sane_lock_method
+      assert_nothing_raised do
+        Person.transaction do
+          person = Person.find 1
+          old, person.first_name = person.first_name, 'fooman'
+          person.lock!
+          assert_equal old, person.first_name
+        end
+      end
+    end
+
+    def test_with_lock_commits_transaction
+      person = Person.find 1
+      person.with_lock do
+        person.first_name = 'fooman'
+        person.save!
+      end
+      assert_equal 'fooman', person.reload.first_name
+    end
+
+    def test_with_lock_rolls_back_transaction
+      person = Person.find 1
+      old = person.first_name
+      person.with_lock do
+        person.first_name = 'fooman'
+        person.save!
+        raise 'oops'
+      end rescue nil
+      assert_equal old, person.reload.first_name
+    end
+
+    if current_adapter?(:PostgreSQLAdapter)
+      def test_lock_sending_custom_lock_statement
+        Person.transaction do
+          person = Person.find(1)
+          assert_sql(/LIMIT 1 FOR SHARE NOWAIT/) do
+            person.lock!('FOR SHARE NOWAIT')
+          end
+        end
+      end
+    end
+
+    if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
+      def test_no_locks_no_wait
+        first, second = duel { Person.find 1 }
+        assert first.end > second.end
+      end
+
+      protected
+        def duel(zzz = 5)
+          t0, t1, t2, t3 = nil, nil, nil, nil
+
+          a = Thread.new do
+            t0 = Time.now
+            Person.transaction do
+              yield
+              sleep zzz       # block thread 2 for zzz seconds
+            end
+            t1 = Time.now
+          end
+
+          b = Thread.new do
+            sleep zzz / 2.0   # ensure thread 1 tx starts first
+            t2 = Time.now
+            Person.transaction { yield }
+            t3 = Time.now
+          end
+
+          a.join
+          b.join
+
+          assert t1 > t0 + zzz
+          assert t2 > t0
+          assert t3 > t2
+          [t0.to_f..t1.to_f, t2.to_f..t3.to_f]
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/log_subscriber_test.rb b/activerecord/test/cases/log_subscriber_test.rb
new file mode 100644
index 0000000000..a578e81844
--- /dev/null
+++ b/activerecord/test/cases/log_subscriber_test.rb
@@ -0,0 +1,136 @@
+require "cases/helper"
+require "models/binary"
+require "models/developer"
+require "models/post"
+require "active_support/log_subscriber/test_helper"
+
+class LogSubscriberTest < ActiveRecord::TestCase
+  include ActiveSupport::LogSubscriber::TestHelper
+  include ActiveSupport::Logger::Severity
+
+  class TestDebugLogSubscriber < ActiveRecord::LogSubscriber
+    attr_reader :debugs
+
+    def initialize
+      @debugs = []
+      super
+    end
+
+    def debug message
+      @debugs << message
+    end
+  end
+
+  fixtures :posts
+
+  def setup
+    @old_logger = ActiveRecord::Base.logger
+    Developer.primary_key
+    super
+    ActiveRecord::LogSubscriber.attach_to(:active_record)
+  end
+
+  def teardown
+    super
+    ActiveRecord::LogSubscriber.log_subscribers.pop
+    ActiveRecord::Base.logger = @old_logger
+  end
+
+  def set_logger(logger)
+    ActiveRecord::Base.logger = logger
+  end
+
+  def test_schema_statements_are_ignored
+    event = Struct.new(:duration, :payload)
+
+    logger = TestDebugLogSubscriber.new
+    assert_equal 0, logger.debugs.length
+
+    logger.sql(event.new(0, sql: 'hi mom!'))
+    assert_equal 1, logger.debugs.length
+
+    logger.sql(event.new(0, sql: 'hi mom!', name: 'foo'))
+    assert_equal 2, logger.debugs.length
+
+    logger.sql(event.new(0, sql: 'hi mom!', name: 'SCHEMA'))
+    assert_equal 2, logger.debugs.length
+  end
+
+  def test_sql_statements_are_not_squeezed
+    event = Struct.new(:duration, :payload)
+    logger = TestDebugLogSubscriber.new
+    logger.sql(event.new(0, sql: 'ruby   rails'))
+    assert_match(/ruby   rails/, logger.debugs.first)
+  end
+
+  def test_ignore_binds_payload_with_nil_column
+    event = Struct.new(:duration, :payload)
+
+    logger = TestDebugLogSubscriber.new
+    logger.sql(event.new(0, sql: 'hi mom!', binds: [[nil, 1]]))
+    assert_equal 1, logger.debugs.length
+  end
+
+  def test_basic_query_logging
+    Developer.all.load
+    wait
+    assert_equal 1, @logger.logged(:debug).size
+    assert_match(/Developer Load/, @logger.logged(:debug).last)
+    assert_match(/SELECT .*?FROM .?developers.?/i, @logger.logged(:debug).last)
+  end
+
+  def test_exists_query_logging
+    Developer.exists? 1
+    wait
+    assert_equal 1, @logger.logged(:debug).size
+    assert_match(/Developer Exists/, @logger.logged(:debug).last)
+    assert_match(/SELECT .*?FROM .?developers.?/i, @logger.logged(:debug).last)
+  end
+
+  def test_cached_queries
+    ActiveRecord::Base.cache do
+      Developer.all.load
+      Developer.all.load
+    end
+    wait
+    assert_equal 2, @logger.logged(:debug).size
+    assert_match(/CACHE/, @logger.logged(:debug).last)
+    assert_match(/SELECT .*?FROM .?developers.?/i, @logger.logged(:debug).last)
+  end
+
+  def test_basic_query_doesnt_log_when_level_is_not_debug
+    @logger.level = INFO
+    Developer.all.load
+    wait
+    assert_equal 0, @logger.logged(:debug).size
+  end
+
+  def test_cached_queries_doesnt_log_when_level_is_not_debug
+    @logger.level = INFO
+    ActiveRecord::Base.cache do
+      Developer.all.load
+      Developer.all.load
+    end
+    wait
+    assert_equal 0, @logger.logged(:debug).size
+  end
+
+  def test_initializes_runtime
+    Thread.new { assert_equal 0, ActiveRecord::LogSubscriber.runtime }.join
+  end
+
+  unless current_adapter?(:Mysql2Adapter)
+    def test_binary_data_is_not_logged
+      Binary.create(data: 'some binary data')
+      wait
+      assert_match(/<16 bytes of binary data>/, @logger.logged(:debug).join)
+    end
+
+    def test_nil_binary_data_is_logged
+      binary = Binary.create(data: "")
+      binary.update_attributes(data: nil)
+      wait
+      assert_match(/<NULL binary data>/, @logger.logged(:debug).join)
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/change_schema_test.rb b/activerecord/test/cases/migration/change_schema_test.rb
new file mode 100644
index 0000000000..c66eaf1ee1
--- /dev/null
+++ b/activerecord/test/cases/migration/change_schema_test.rb
@@ -0,0 +1,397 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class Migration
+    class ChangeSchemaTest < ActiveRecord::TestCase
+      attr_reader :connection, :table_name
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @table_name = :testings
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+        ActiveRecord::Base.primary_key_prefix_type = nil
+        ActiveRecord::Base.clear_cache!
+      end
+
+      def test_create_table_without_id
+        testing_table_with_only_foo_attribute do
+          assert_equal connection.columns(:testings).size, 1
+        end
+      end
+
+      def test_add_column_with_primary_key_attribute
+        testing_table_with_only_foo_attribute do
+          connection.add_column :testings, :id, :primary_key
+          assert_equal connection.columns(:testings).size, 2
+        end
+      end
+
+      def test_create_table_adds_id
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        assert_equal %w(id foo), connection.columns(:testings).map(&:name)
+      end
+
+      def test_create_table_with_not_null_column
+        connection.create_table :testings do |t|
+          t.column :foo, :string, :null => false
+        end
+
+        assert_raises(ActiveRecord::StatementInvalid) do
+          connection.execute "insert into testings (foo) values (NULL)"
+        end
+      end
+
+      def test_create_table_with_defaults
+        # MySQL doesn't allow defaults on TEXT or BLOB columns.
+        mysql = current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+
+        connection.create_table :testings do |t|
+          t.column :one, :string, :default => "hello"
+          t.column :two, :boolean, :default => true
+          t.column :three, :boolean, :default => false
+          t.column :four, :integer, :default => 1
+          t.column :five, :text, :default => "hello" unless mysql
+        end
+
+        columns = connection.columns(:testings)
+        one = columns.detect { |c| c.name == "one" }
+        two = columns.detect { |c| c.name == "two" }
+        three = columns.detect { |c| c.name == "three" }
+        four = columns.detect { |c| c.name == "four" }
+        five = columns.detect { |c| c.name == "five" } unless mysql
+
+        assert_equal "hello", one.default
+        assert_equal true, two.type_cast_from_database(two.default)
+        assert_equal false, three.type_cast_from_database(three.default)
+        assert_equal '1', four.default
+        assert_equal "hello", five.default unless mysql
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_add_column_with_array
+          connection.create_table :testings
+          connection.add_column :testings, :foo, :string, :array => true
+
+          columns = connection.columns(:testings)
+          array_column = columns.detect { |c| c.name == "foo" }
+
+          assert array_column.array
+        end
+
+        def test_create_table_with_array_column
+          connection.create_table :testings do |t|
+            t.string :foo, :array => true
+          end
+
+          columns = connection.columns(:testings)
+          array_column = columns.detect { |c| c.name == "foo" }
+
+          assert array_column.array
+        end
+      end
+
+      def test_create_table_with_limits
+        connection.create_table :testings do |t|
+          t.column :foo, :string, :limit => 255
+
+          t.column :default_int, :integer
+
+          t.column :one_int,    :integer, :limit => 1
+          t.column :four_int,   :integer, :limit => 4
+          t.column :eight_int,  :integer, :limit => 8
+        end
+
+        columns = connection.columns(:testings)
+        foo = columns.detect { |c| c.name == "foo" }
+        assert_equal 255, foo.limit
+
+        default = columns.detect { |c| c.name == "default_int" }
+        one     = columns.detect { |c| c.name == "one_int"     }
+        four    = columns.detect { |c| c.name == "four_int"    }
+        eight   = columns.detect { |c| c.name == "eight_int"   }
+
+        if current_adapter?(:PostgreSQLAdapter)
+          assert_equal 'integer', default.sql_type
+          assert_equal 'smallint', one.sql_type
+          assert_equal 'integer', four.sql_type
+          assert_equal 'bigint', eight.sql_type
+        elsif current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+          assert_match 'int(11)', default.sql_type
+          assert_match 'tinyint', one.sql_type
+          assert_match 'int', four.sql_type
+          assert_match 'bigint', eight.sql_type
+        elsif current_adapter?(:OracleAdapter)
+          assert_equal 'NUMBER(38)', default.sql_type
+          assert_equal 'NUMBER(1)', one.sql_type
+          assert_equal 'NUMBER(4)', four.sql_type
+          assert_equal 'NUMBER(8)', eight.sql_type
+        end
+      end
+
+      def test_create_table_with_primary_key_prefix_as_table_name_with_underscore
+        ActiveRecord::Base.primary_key_prefix_type = :table_name_with_underscore
+
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        assert_equal %w(testing_id foo), connection.columns(:testings).map(&:name)
+      end
+
+      def test_create_table_with_primary_key_prefix_as_table_name
+        ActiveRecord::Base.primary_key_prefix_type = :table_name
+
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        assert_equal %w(testingid foo), connection.columns(:testings).map(&:name)
+      end
+
+      def test_create_table_raises_when_redefining_primary_key_column
+        error = assert_raise(ArgumentError) do
+          connection.create_table :testings do |t|
+            t.column :id, :string
+          end
+        end
+
+        assert_equal "you can't redefine the primary key column 'id'. To define a custom primary key, pass { id: false } to create_table.", error.message
+      end
+
+      def test_create_table_raises_when_redefining_custom_primary_key_column
+        error = assert_raise(ArgumentError) do
+          connection.create_table :testings, primary_key: :testing_id do |t|
+            t.column :testing_id, :string
+          end
+        end
+
+        assert_equal "you can't redefine the primary key column 'testing_id'. To define a custom primary key, pass { id: false } to create_table.", error.message
+      end
+
+      def test_create_table_with_timestamps_should_create_datetime_columns
+        connection.create_table table_name do |t|
+          t.timestamps
+        end
+        created_columns = connection.columns(table_name)
+
+        created_at_column = created_columns.detect {|c| c.name == 'created_at' }
+        updated_at_column = created_columns.detect {|c| c.name == 'updated_at' }
+
+        assert created_at_column.null
+        assert updated_at_column.null
+      end
+
+      def test_create_table_with_timestamps_should_create_datetime_columns_with_options
+        connection.create_table table_name do |t|
+          t.timestamps :null => false
+        end
+        created_columns = connection.columns(table_name)
+
+        created_at_column = created_columns.detect {|c| c.name == 'created_at' }
+        updated_at_column = created_columns.detect {|c| c.name == 'updated_at' }
+
+        assert !created_at_column.null
+        assert !updated_at_column.null
+      end
+
+      def test_create_table_without_a_block
+        connection.create_table table_name
+      end
+
+      # SQLite3 will not allow you to add a NOT NULL
+      # column to a table without a default value.
+      unless current_adapter?(:SQLite3Adapter)
+        def test_add_column_not_null_without_default
+          connection.create_table :testings do |t|
+            t.column :foo, :string
+          end
+          connection.add_column :testings, :bar, :string, :null => false
+
+          assert_raise(ActiveRecord::StatementInvalid) do
+            connection.execute "insert into testings (foo, bar) values ('hello', NULL)"
+          end
+        end
+      end
+
+      def test_add_column_not_null_with_default
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        con = connection
+        connection.execute "insert into testings (#{con.quote_column_name('id')}, #{con.quote_column_name('foo')}) values (1, 'hello')"
+        assert_nothing_raised {connection.add_column :testings, :bar, :string, :null => false, :default => "default" }
+
+        assert_raises(ActiveRecord::StatementInvalid) do
+          connection.execute "insert into testings (#{con.quote_column_name('id')}, #{con.quote_column_name('foo')}, #{con.quote_column_name('bar')}) values (2, 'hello', NULL)"
+        end
+      end
+
+      def test_add_column_with_timestamp_type
+        connection.create_table :testings do |t|
+          t.column :foo, :timestamp
+        end
+
+        klass = Class.new(ActiveRecord::Base)
+        klass.table_name = 'testings'
+
+        assert_equal :datetime, klass.columns_hash['foo'].type
+
+        if current_adapter?(:PostgreSQLAdapter)
+          assert_equal 'timestamp without time zone', klass.columns_hash['foo'].sql_type
+        else
+          assert_equal klass.connection.type_to_sql('datetime'), klass.columns_hash['foo'].sql_type
+        end
+      end
+
+      def test_change_column_quotes_column_names
+        connection.create_table :testings do |t|
+          t.column :select, :string
+        end
+
+        connection.change_column :testings, :select, :string, :limit => 10
+
+        # Oracle needs primary key value from sequence
+        if current_adapter?(:OracleAdapter)
+          connection.execute "insert into testings (id, #{connection.quote_column_name('select')}) values (testings_seq.nextval, '7 chars')"
+        else
+          connection.execute "insert into testings (#{connection.quote_column_name('select')}) values ('7 chars')"
+        end
+      end
+
+      def test_keeping_default_and_notnull_constraints_on_change
+        connection.create_table :testings do |t|
+          t.column :title, :string
+        end
+        person_klass = Class.new(ActiveRecord::Base)
+        person_klass.table_name = 'testings'
+
+        person_klass.connection.add_column "testings", "wealth", :integer, :null => false, :default => 99
+        person_klass.reset_column_information
+        assert_equal 99, person_klass.column_defaults["wealth"]
+        assert_equal false, person_klass.columns_hash["wealth"].null
+        # Oracle needs primary key value from sequence
+        if current_adapter?(:OracleAdapter)
+          assert_nothing_raised {person_klass.connection.execute("insert into testings (id, title) values (testings_seq.nextval, 'tester')")}
+        else
+          assert_nothing_raised {person_klass.connection.execute("insert into testings (title) values ('tester')")}
+        end
+
+        # change column default to see that column doesn't lose its not null definition
+        person_klass.connection.change_column_default "testings", "wealth", 100
+        person_klass.reset_column_information
+        assert_equal 100, person_klass.column_defaults["wealth"]
+        assert_equal false, person_klass.columns_hash["wealth"].null
+
+        # rename column to see that column doesn't lose its not null and/or default definition
+        person_klass.connection.rename_column "testings", "wealth", "money"
+        person_klass.reset_column_information
+        assert_nil person_klass.columns_hash["wealth"]
+        assert_equal 100, person_klass.column_defaults["money"]
+        assert_equal false, person_klass.columns_hash["money"].null
+
+        # change column
+        person_klass.connection.change_column "testings", "money", :integer, :null => false, :default => 1000
+        person_klass.reset_column_information
+        assert_equal 1000, person_klass.column_defaults["money"]
+        assert_equal false, person_klass.columns_hash["money"].null
+
+        # change column, make it nullable and clear default
+        person_klass.connection.change_column "testings", "money", :integer, :null => true, :default => nil
+        person_klass.reset_column_information
+        assert_nil person_klass.columns_hash["money"].default
+        assert_equal true, person_klass.columns_hash["money"].null
+
+        # change_column_null, make it not nullable and set null values to a default value
+        person_klass.connection.execute('UPDATE testings SET money = NULL')
+        person_klass.connection.change_column_null "testings", "money", false, 2000
+        person_klass.reset_column_information
+        assert_nil person_klass.columns_hash["money"].default
+        assert_equal false, person_klass.columns_hash["money"].null
+        assert_equal 2000, connection.select_values("SELECT money FROM testings").first.to_i
+      end
+
+      def test_change_column_null
+        testing_table_with_only_foo_attribute do
+          notnull_migration = Class.new(ActiveRecord::Migration) do
+            def change
+              change_column_null :testings, :foo, false
+            end
+          end
+          notnull_migration.new.suppress_messages do
+            notnull_migration.migrate(:up)
+            assert_equal false, connection.columns(:testings).find{ |c| c.name == "foo"}.null
+            notnull_migration.migrate(:down)
+            assert connection.columns(:testings).find{ |c| c.name == "foo"}.null
+          end
+        end
+      end
+
+      def test_column_exists
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+        end
+
+        assert connection.column_exists?(:testings, :foo)
+        assert_not connection.column_exists?(:testings, :bar)
+      end
+
+      def test_column_exists_with_type
+        connection.create_table :testings do |t|
+          t.column :foo, :string
+          t.column :bar, :decimal, :precision => 8, :scale => 2
+        end
+
+        assert connection.column_exists?(:testings, :foo, :string)
+        assert_not connection.column_exists?(:testings, :foo, :integer)
+
+        assert connection.column_exists?(:testings, :bar, :decimal)
+        assert_not connection.column_exists?(:testings, :bar, :integer)
+      end
+
+      def test_column_exists_with_definition
+        connection.create_table :testings do |t|
+          t.column :foo, :string, limit: 100
+          t.column :bar, :decimal, precision: 8, scale: 2
+          t.column :taggable_id, :integer, null: false
+          t.column :taggable_type, :string, default: 'Photo'
+        end
+
+        assert connection.column_exists?(:testings, :foo, :string, limit: 100)
+        assert_not connection.column_exists?(:testings, :foo, :string, limit: nil)
+        assert connection.column_exists?(:testings, :bar, :decimal, precision: 8, scale: 2)
+        assert_not connection.column_exists?(:testings, :bar, :decimal, precision: nil, scale: nil)
+        assert connection.column_exists?(:testings, :taggable_id, :integer, null: false)
+        assert_not connection.column_exists?(:testings, :taggable_id, :integer, null: true)
+        assert connection.column_exists?(:testings, :taggable_type, :string, default: 'Photo')
+        assert_not connection.column_exists?(:testings, :taggable_type, :string, default: nil)
+      end
+
+      def test_column_exists_on_table_with_no_options_parameter_supplied
+        connection.create_table :testings do |t|
+          t.string :foo
+        end
+        connection.change_table :testings do |t|
+          assert t.column_exists?(:foo)
+          assert !(t.column_exists?(:bar))
+        end
+      end
+
+      private
+      def testing_table_with_only_foo_attribute
+        connection.create_table :testings, :id => false do |t|
+          t.column :foo, :string
+        end
+
+        yield
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/change_table_test.rb b/activerecord/test/cases/migration/change_table_test.rb
new file mode 100644
index 0000000000..3e9d957ed3
--- /dev/null
+++ b/activerecord/test/cases/migration/change_table_test.rb
@@ -0,0 +1,218 @@
+require "cases/migration/helper"
+require "minitest/mock"
+
+module ActiveRecord
+  class Migration
+    class TableTest < ActiveRecord::TestCase
+      def setup
+        @connection = Minitest::Mock.new
+      end
+
+      teardown do
+        assert @connection.verify
+      end
+
+      def with_change_table
+        yield ConnectionAdapters::Table.new(:delete_me, @connection)
+      end
+
+      def test_references_column_type_adds_id
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :customer, {}]
+          t.references :customer
+        end
+      end
+
+      def test_remove_references_column_type_removes_id
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :customer, {}]
+          t.remove_references :customer
+        end
+      end
+
+      def test_add_belongs_to_works_like_add_references
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :customer, {}]
+          t.belongs_to :customer
+        end
+      end
+
+      def test_remove_belongs_to_works_like_remove_references
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :customer, {}]
+          t.remove_belongs_to :customer
+        end
+      end
+
+      def test_references_column_type_with_polymorphic_adds_type
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :taggable, polymorphic: true]
+          t.references :taggable, polymorphic: true
+        end
+      end
+
+      def test_remove_references_column_type_with_polymorphic_removes_type
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :taggable, polymorphic: true]
+          t.remove_references :taggable, polymorphic: true
+        end
+      end
+
+      def test_references_column_type_with_polymorphic_and_options_null_is_false_adds_table_flag
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :taggable, polymorphic: true, null: false]
+          t.references :taggable, polymorphic: true, null: false
+        end
+      end
+
+      def test_remove_references_column_type_with_polymorphic_and_options_null_is_false_removes_table_flag
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :taggable, polymorphic: true, null: false]
+          t.remove_references :taggable, polymorphic: true, null: false
+        end
+      end
+
+      def test_references_column_type_with_polymorphic_and_type
+        with_change_table do |t|
+          @connection.expect :add_reference, nil, [:delete_me, :taggable, polymorphic: true, type: :string]
+          t.references :taggable, polymorphic: true, type: :string
+        end
+      end
+
+      def test_remove_references_column_type_with_polymorphic_and_type
+        with_change_table do |t|
+          @connection.expect :remove_reference, nil, [:delete_me, :taggable, polymorphic: true, type: :string]
+          t.remove_references :taggable, polymorphic: true, type: :string
+        end
+      end
+
+      def test_timestamps_creates_updated_at_and_created_at
+        with_change_table do |t|
+          @connection.expect :add_timestamps, nil, [:delete_me]
+          t.timestamps
+        end
+      end
+
+      def test_remove_timestamps_creates_updated_at_and_created_at
+        with_change_table do |t|
+          @connection.expect :remove_timestamps, nil, [:delete_me]
+          t.remove_timestamps
+        end
+      end
+
+      def test_integer_creates_integer_column
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :foo, :integer, {}]
+          @connection.expect :add_column, nil, [:delete_me, :bar, :integer, {}]
+          t.integer :foo, :bar
+        end
+      end
+
+      def test_string_creates_string_column
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :foo, :string, {}]
+          @connection.expect :add_column, nil, [:delete_me, :bar, :string, {}]
+          t.string :foo, :bar
+        end
+      end
+
+      def test_column_creates_column
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :bar, :integer, {}]
+          t.column :bar, :integer
+        end
+      end
+
+      def test_column_creates_column_with_options
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :bar, :integer, {:null => false}]
+          t.column :bar, :integer, :null => false
+        end
+      end
+
+      def test_index_creates_index
+        with_change_table do |t|
+          @connection.expect :add_index, nil, [:delete_me, :bar, {}]
+          t.index :bar
+        end
+      end
+
+      def test_index_creates_index_with_options
+        with_change_table do |t|
+          @connection.expect :add_index, nil, [:delete_me, :bar, {:unique => true}]
+          t.index :bar, :unique => true
+        end
+      end
+
+      def test_index_exists
+        with_change_table do |t|
+          @connection.expect :index_exists?, nil, [:delete_me, :bar, {}]
+          t.index_exists?(:bar)
+        end
+      end
+
+      def test_index_exists_with_options
+        with_change_table do |t|
+          @connection.expect :index_exists?, nil, [:delete_me, :bar, {:unique => true}]
+          t.index_exists?(:bar, :unique => true)
+        end
+      end
+
+      def test_rename_index_renames_index
+        with_change_table do |t|
+          @connection.expect :rename_index, nil, [:delete_me, :bar, :baz]
+          t.rename_index :bar, :baz
+        end
+      end
+
+      def test_change_changes_column
+        with_change_table do |t|
+          @connection.expect :change_column, nil, [:delete_me, :bar, :string, {}]
+          t.change :bar, :string
+        end
+      end
+
+      def test_change_changes_column_with_options
+        with_change_table do |t|
+          @connection.expect :change_column, nil, [:delete_me, :bar, :string, {:null => true}]
+          t.change :bar, :string, :null => true
+        end
+      end
+
+      def test_change_default_changes_column
+        with_change_table do |t|
+          @connection.expect :change_column_default, nil, [:delete_me, :bar, :string]
+          t.change_default :bar, :string
+        end
+      end
+
+      def test_remove_drops_single_column
+        with_change_table do |t|
+          @connection.expect :remove_columns, nil, [:delete_me, :bar]
+          t.remove :bar
+        end
+      end
+
+      def test_remove_drops_multiple_columns
+        with_change_table do |t|
+          @connection.expect :remove_columns, nil, [:delete_me, :bar, :baz]
+          t.remove :bar, :baz
+        end
+      end
+
+      def test_remove_index_removes_index_with_options
+        with_change_table do |t|
+          @connection.expect :remove_index, nil, [:delete_me, {:unique => true}]
+          t.remove_index :unique => true
+        end
+      end
+
+      def test_rename_renames_column
+        with_change_table do |t|
+          @connection.expect :rename_column, nil, [:delete_me, :bar, :baz]
+          t.rename :bar, :baz
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/column_attributes_test.rb b/activerecord/test/cases/migration/column_attributes_test.rb
new file mode 100644
index 0000000000..763aa88f72
--- /dev/null
+++ b/activerecord/test/cases/migration/column_attributes_test.rb
@@ -0,0 +1,185 @@
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class ColumnAttributesTest < ActiveRecord::TestCase
+      include ActiveRecord::Migration::TestHelper
+
+      self.use_transactional_fixtures = false
+
+      def test_add_column_newline_default
+        string = "foo\nbar"
+        add_column 'test_models', 'command', :string, :default => string
+        TestModel.reset_column_information
+
+        assert_equal string, TestModel.new.command
+      end
+
+      def test_add_remove_single_field_using_string_arguments
+        assert_no_column TestModel, :last_name
+
+        add_column 'test_models', 'last_name', :string
+        assert_column TestModel, :last_name
+
+        remove_column 'test_models', 'last_name'
+        assert_no_column TestModel, :last_name
+      end
+
+      def test_add_remove_single_field_using_symbol_arguments
+        assert_no_column TestModel, :last_name
+
+        add_column :test_models, :last_name, :string
+        assert_column TestModel, :last_name
+
+        remove_column :test_models, :last_name
+        assert_no_column TestModel, :last_name
+      end
+
+      def test_add_column_without_limit
+        # TODO: limit: nil should work with all adapters.
+        skip "MySQL wrongly enforces a limit of 255" if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+        add_column :test_models, :description, :string, limit: nil
+        TestModel.reset_column_information
+        assert_nil TestModel.columns_hash["description"].limit
+      end
+
+      if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+        def test_unabstracted_database_dependent_types
+          add_column :test_models, :intelligence_quotient, :tinyint
+          TestModel.reset_column_information
+          assert_match(/tinyint/, TestModel.columns_hash['intelligence_quotient'].sql_type)
+        end
+      end
+
+      unless current_adapter?(:SQLite3Adapter)
+        # We specifically do a manual INSERT here, and then test only the SELECT
+        # functionality. This allows us to more easily catch INSERT being broken,
+        # but SELECT actually working fine.
+        def test_native_decimal_insert_manual_vs_automatic
+          correct_value = '0012345678901234567890.0123456789'.to_d
+
+          connection.add_column "test_models", "wealth", :decimal, :precision => '30', :scale => '10'
+
+          # Do a manual insertion
+          if current_adapter?(:OracleAdapter)
+            connection.execute "insert into test_models (id, wealth) values (people_seq.nextval, 12345678901234567890.0123456789)"
+          elsif current_adapter?(:MysqlAdapter) && Mysql.client_version < 50003 #before MySQL 5.0.3 decimals stored as strings
+            connection.execute "insert into test_models (wealth) values ('12345678901234567890.0123456789')"
+          elsif current_adapter?(:PostgreSQLAdapter)
+            connection.execute "insert into test_models (wealth) values (12345678901234567890.0123456789)"
+          else
+            connection.execute "insert into test_models (wealth) values (12345678901234567890.0123456789)"
+          end
+
+          # SELECT
+          row = TestModel.first
+          assert_kind_of BigDecimal, row.wealth
+
+          # If this assert fails, that means the SELECT is broken!
+          unless current_adapter?(:SQLite3Adapter)
+            assert_equal correct_value, row.wealth
+          end
+
+          # Reset to old state
+          TestModel.delete_all
+
+          # Now use the Rails insertion
+          TestModel.create :wealth => BigDecimal.new("12345678901234567890.0123456789")
+
+          # SELECT
+          row = TestModel.first
+          assert_kind_of BigDecimal, row.wealth
+
+          # If these asserts fail, that means the INSERT (create function, or cast to SQL) is broken!
+          assert_equal correct_value, row.wealth
+        end
+      end
+
+      def test_add_column_with_precision_and_scale
+        connection.add_column 'test_models', 'wealth', :decimal, :precision => 9, :scale => 7
+
+        wealth_column = TestModel.columns_hash['wealth']
+        assert_equal 9, wealth_column.precision
+        assert_equal 7, wealth_column.scale
+      end
+
+      if current_adapter?(:SQLite3Adapter)
+        def test_change_column_preserve_other_column_precision_and_scale
+          connection.add_column 'test_models', 'last_name', :string
+          connection.add_column 'test_models', 'wealth', :decimal, :precision => 9, :scale => 7
+
+          wealth_column = TestModel.columns_hash['wealth']
+          assert_equal 9, wealth_column.precision
+          assert_equal 7, wealth_column.scale
+
+          connection.change_column 'test_models', 'last_name', :string, :null => false
+          TestModel.reset_column_information
+
+          wealth_column = TestModel.columns_hash['wealth']
+          assert_equal 9, wealth_column.precision
+          assert_equal 7, wealth_column.scale
+        end
+      end
+
+      unless current_adapter?(:SQLite3Adapter)
+        def test_native_types
+          add_column "test_models", "first_name", :string
+          add_column "test_models", "last_name", :string
+          add_column "test_models", "bio", :text
+          add_column "test_models", "age", :integer
+          add_column "test_models", "height", :float
+          add_column "test_models", "wealth", :decimal, :precision => '30', :scale => '10'
+          add_column "test_models", "birthday", :datetime
+          add_column "test_models", "favorite_day", :date
+          add_column "test_models", "moment_of_truth", :datetime
+          add_column "test_models", "male", :boolean
+
+          TestModel.create :first_name => 'bob', :last_name => 'bobsen',
+            :bio => "I was born ....", :age => 18, :height => 1.78,
+            :wealth => BigDecimal.new("12345678901234567890.0123456789"),
+            :birthday => 18.years.ago, :favorite_day => 10.days.ago,
+            :moment_of_truth => "1782-10-10 21:40:18", :male => true
+
+          bob = TestModel.first
+          assert_equal 'bob', bob.first_name
+          assert_equal 'bobsen', bob.last_name
+          assert_equal "I was born ....", bob.bio
+          assert_equal 18, bob.age
+
+          # Test for 30 significant digits (beyond the 16 of float), 10 of them
+          # after the decimal place.
+
+          assert_equal BigDecimal.new("0012345678901234567890.0123456789"), bob.wealth
+
+          assert_equal true, bob.male?
+
+          assert_equal String, bob.first_name.class
+          assert_equal String, bob.last_name.class
+          assert_equal String, bob.bio.class
+          assert_equal Fixnum, bob.age.class
+          assert_equal Time, bob.birthday.class
+
+          if current_adapter?(:OracleAdapter)
+            # Oracle doesn't differentiate between date/time
+            assert_equal Time, bob.favorite_day.class
+          else
+            assert_equal Date, bob.favorite_day.class
+          end
+
+          assert_instance_of TrueClass, bob.male?
+          assert_kind_of BigDecimal, bob.wealth
+        end
+      end
+
+      if current_adapter?(:MysqlAdapter, :Mysql2Adapter, :PostgreSQLAdapter)
+        def test_out_of_range_limit_should_raise
+          assert_raise(ActiveRecordError) { add_column :test_models, :integer_too_big, :integer, :limit => 10 }
+
+          unless current_adapter?(:PostgreSQLAdapter)
+            assert_raise(ActiveRecordError) { add_column :test_models, :text_too_big, :integer, :limit => 0xfffffffff }
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/column_positioning_test.rb b/activerecord/test/cases/migration/column_positioning_test.rb
new file mode 100644
index 0000000000..77a752f050
--- /dev/null
+++ b/activerecord/test/cases/migration/column_positioning_test.rb
@@ -0,0 +1,56 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class Migration
+    class ColumnPositioningTest < ActiveRecord::TestCase
+      attr_reader :connection, :table_name
+      alias :conn :connection
+
+      def setup
+        super
+
+        @connection = ActiveRecord::Base.connection
+
+        connection.create_table :testings, :id => false do |t|
+          t.column :first, :integer
+          t.column :second, :integer
+          t.column :third, :integer
+        end
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+        ActiveRecord::Base.primary_key_prefix_type = nil
+      end
+
+      if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+        def test_column_positioning
+          assert_equal %w(first second third), conn.columns(:testings).map {|c| c.name }
+        end
+
+        def test_add_column_with_positioning
+          conn.add_column :testings, :new_col, :integer
+          assert_equal %w(first second third new_col), conn.columns(:testings).map {|c| c.name }
+        end
+
+        def test_add_column_with_positioning_first
+          conn.add_column :testings, :new_col, :integer, :first => true
+          assert_equal %w(new_col first second third), conn.columns(:testings).map {|c| c.name }
+        end
+
+        def test_add_column_with_positioning_after
+          conn.add_column :testings, :new_col, :integer, :after => :first
+          assert_equal %w(first new_col second third), conn.columns(:testings).map {|c| c.name }
+        end
+
+        def test_change_column_with_positioning
+          conn.change_column :testings, :second, :integer, :first => true
+          assert_equal %w(second first third), conn.columns(:testings).map {|c| c.name }
+
+          conn.change_column :testings, :second, :integer, :after => :third
+          assert_equal %w(first third second), conn.columns(:testings).map {|c| c.name }
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/columns_test.rb b/activerecord/test/cases/migration/columns_test.rb
new file mode 100644
index 0000000000..4e6d7963aa
--- /dev/null
+++ b/activerecord/test/cases/migration/columns_test.rb
@@ -0,0 +1,296 @@
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class ColumnsTest < ActiveRecord::TestCase
+      include ActiveRecord::Migration::TestHelper
+
+      self.use_transactional_fixtures = false
+
+      # FIXME: this is more of an integration test with AR::Base and the
+      # schema modifications.  Maybe we should move this?
+      def test_add_rename
+        add_column "test_models", "girlfriend", :string
+        TestModel.reset_column_information
+
+        TestModel.create :girlfriend => 'bobette'
+
+        rename_column "test_models", "girlfriend", "exgirlfriend"
+
+        TestModel.reset_column_information
+        bob = TestModel.first
+
+        assert_equal "bobette", bob.exgirlfriend
+      end
+
+      # FIXME: another integration test.  We should decouple this from the
+      # AR::Base implementation.
+      def test_rename_column_using_symbol_arguments
+        add_column :test_models, :first_name, :string
+
+        TestModel.create :first_name => 'foo'
+
+        rename_column :test_models, :first_name, :nick_name
+        TestModel.reset_column_information
+        assert TestModel.column_names.include?("nick_name")
+        assert_equal ['foo'], TestModel.all.map(&:nick_name)
+      end
+
+      # FIXME: another integration test.  We should decouple this from the
+      # AR::Base implementation.
+      def test_rename_column
+        add_column "test_models", "first_name", "string"
+
+        TestModel.create :first_name => 'foo'
+
+        rename_column "test_models", "first_name", "nick_name"
+        TestModel.reset_column_information
+        assert TestModel.column_names.include?("nick_name")
+        assert_equal ['foo'], TestModel.all.map(&:nick_name)
+      end
+
+      def test_rename_column_preserves_default_value_not_null
+        add_column 'test_models', 'salary', :integer, :default => 70000
+
+        default_before = connection.columns("test_models").find { |c| c.name == "salary" }.default
+        assert_equal '70000', default_before
+
+        rename_column "test_models", "salary", "annual_salary"
+
+        assert TestModel.column_names.include?("annual_salary")
+        default_after = connection.columns("test_models").find { |c| c.name == "annual_salary" }.default
+        assert_equal '70000', default_after
+      end
+
+      if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+        def test_mysql_rename_column_preserves_auto_increment
+          rename_column "test_models", "id", "id_test"
+          assert_equal "auto_increment", connection.columns("test_models").find { |c| c.name == "id_test" }.extra
+        end
+      end
+
+      def test_rename_nonexistent_column
+        exception = if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
+                      ActiveRecord::StatementInvalid
+                    else
+                      ActiveRecord::ActiveRecordError
+                    end
+        assert_raise(exception) do
+          rename_column "test_models", "nonexistent", "should_fail"
+        end
+      end
+
+      def test_rename_column_with_sql_reserved_word
+        add_column 'test_models', 'first_name', :string
+        rename_column "test_models", "first_name", "group"
+
+        assert TestModel.column_names.include?("group")
+      end
+
+      def test_rename_column_with_an_index
+        add_column "test_models", :hat_name, :string
+        add_index :test_models, :hat_name
+
+        assert_equal 1, connection.indexes('test_models').size
+        rename_column "test_models", "hat_name", "name"
+
+        assert_equal ['index_test_models_on_name'], connection.indexes('test_models').map(&:name)
+      end
+
+      def test_rename_column_with_multi_column_index
+        add_column "test_models", :hat_size, :integer
+        add_column "test_models", :hat_style, :string, limit: 100
+        add_index "test_models", ["hat_style", "hat_size"], unique: true
+
+        rename_column "test_models", "hat_size", 'size'
+        if current_adapter? :OracleAdapter
+          assert_equal ['i_test_models_hat_style_size'], connection.indexes('test_models').map(&:name)
+        else
+          assert_equal ['index_test_models_on_hat_style_and_size'], connection.indexes('test_models').map(&:name)
+        end
+
+        rename_column "test_models", "hat_style", 'style'
+        if current_adapter? :OracleAdapter
+          assert_equal ['i_test_models_style_size'], connection.indexes('test_models').map(&:name)
+        else
+          assert_equal ['index_test_models_on_style_and_size'], connection.indexes('test_models').map(&:name)
+        end
+      end
+
+      def test_rename_column_does_not_rename_custom_named_index
+        add_column "test_models", :hat_name, :string
+        add_index :test_models, :hat_name, :name => 'idx_hat_name'
+
+        assert_equal 1, connection.indexes('test_models').size
+        rename_column "test_models", "hat_name", "name"
+        assert_equal ['idx_hat_name'], connection.indexes('test_models').map(&:name)
+      end
+
+      def test_remove_column_with_index
+        add_column "test_models", :hat_name, :string
+        add_index :test_models, :hat_name
+
+        assert_equal 1, connection.indexes('test_models').size
+        remove_column("test_models", "hat_name")
+        assert_equal 0, connection.indexes('test_models').size
+      end
+
+      def test_remove_column_with_multi_column_index
+        add_column "test_models", :hat_size, :integer
+        add_column "test_models", :hat_style, :string, :limit => 100
+        add_index "test_models", ["hat_style", "hat_size"], :unique => true
+
+        assert_equal 1, connection.indexes('test_models').size
+        remove_column("test_models", "hat_size")
+
+        # Every database and/or database adapter has their own behavior
+        # if it drops the multi-column index when any of the indexed columns dropped by remove_column.
+        if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
+          assert_equal [], connection.indexes('test_models').map(&:name)
+        else
+          assert_equal ['index_test_models_on_hat_style_and_hat_size'], connection.indexes('test_models').map(&:name)
+        end
+      end
+
+      def test_change_type_of_not_null_column
+        change_column "test_models", "updated_at", :datetime, :null => false
+        change_column "test_models", "updated_at", :datetime, :null => false
+
+        TestModel.reset_column_information
+        assert_equal false, TestModel.columns_hash['updated_at'].null
+      ensure
+        change_column "test_models", "updated_at", :datetime, :null => true
+      end
+
+      def test_change_column_nullability
+        add_column "test_models", "funny", :boolean
+        assert TestModel.columns_hash["funny"].null, "Column 'funny' must initially allow nulls"
+
+        change_column "test_models", "funny", :boolean, :null => false, :default => true
+
+        TestModel.reset_column_information
+        assert_not TestModel.columns_hash["funny"].null, "Column 'funny' must *not* allow nulls at this point"
+
+        change_column "test_models", "funny", :boolean, :null => true
+        TestModel.reset_column_information
+        assert TestModel.columns_hash["funny"].null, "Column 'funny' must allow nulls again at this point"
+      end
+
+      def test_change_column
+        add_column 'test_models', 'age', :integer
+        add_column 'test_models', 'approved', :boolean, :default => true
+
+        old_columns = connection.columns(TestModel.table_name)
+
+        assert old_columns.find { |c| c.name == 'age' && c.type == :integer }
+
+        change_column "test_models", "age", :string
+
+        new_columns = connection.columns(TestModel.table_name)
+
+        assert_not new_columns.find { |c| c.name == 'age' and c.type == :integer }
+        assert new_columns.find { |c| c.name == 'age' and c.type == :string }
+
+        old_columns = connection.columns(TestModel.table_name)
+        assert old_columns.find { |c|
+          default = c.type_cast_from_database(c.default)
+          c.name == 'approved' && c.type == :boolean && default == true
+        }
+
+        change_column :test_models, :approved, :boolean, :default => false
+        new_columns = connection.columns(TestModel.table_name)
+
+        assert_not new_columns.find { |c|
+          default = c.type_cast_from_database(c.default)
+          c.name == 'approved' and c.type == :boolean and default == true
+        }
+        assert new_columns.find { |c|
+          default = c.type_cast_from_database(c.default)
+          c.name == 'approved' and c.type == :boolean and default == false
+        }
+        change_column :test_models, :approved, :boolean, :default => true
+      end
+
+      def test_change_column_with_nil_default
+        add_column "test_models", "contributor", :boolean, :default => true
+        assert TestModel.new.contributor?
+
+        change_column "test_models", "contributor", :boolean, :default => nil
+        TestModel.reset_column_information
+        assert_not TestModel.new.contributor?
+        assert_nil TestModel.new.contributor
+      end
+
+      def test_change_column_with_new_default
+        add_column "test_models", "administrator", :boolean, :default => true
+        assert TestModel.new.administrator?
+
+        change_column "test_models", "administrator", :boolean, :default => false
+        TestModel.reset_column_information
+        assert_not TestModel.new.administrator?
+      end
+
+      def test_change_column_with_custom_index_name
+        add_column "test_models", "category", :string
+        add_index :test_models, :category, name: 'test_models_categories_idx'
+
+        assert_equal ['test_models_categories_idx'], connection.indexes('test_models').map(&:name)
+        change_column "test_models", "category", :string, null: false, default: 'article'
+
+        assert_equal ['test_models_categories_idx'], connection.indexes('test_models').map(&:name)
+      end
+
+      def test_change_column_with_long_index_name
+        table_name_prefix = 'test_models_'
+        long_index_name = table_name_prefix + ('x' * (connection.allowed_index_name_length - table_name_prefix.length))
+        add_column "test_models", "category", :string
+        add_index :test_models, :category, name: long_index_name
+
+        change_column "test_models", "category", :string, null: false, default: 'article'
+
+        assert_equal [long_index_name], connection.indexes('test_models').map(&:name)
+      end
+
+      def test_change_column_default
+        add_column "test_models", "first_name", :string
+        connection.change_column_default "test_models", "first_name", "Tester"
+
+        assert_equal "Tester", TestModel.new.first_name
+      end
+
+      def test_change_column_default_to_null
+        add_column "test_models", "first_name", :string
+        connection.change_column_default "test_models", "first_name", nil
+        assert_nil TestModel.new.first_name
+      end
+
+      def test_remove_column_no_second_parameter_raises_exception
+        assert_raise(ArgumentError) { connection.remove_column("funny") }
+      end
+
+      def test_removing_and_renaming_column_preserves_custom_primary_key
+        connection.create_table "my_table", primary_key: "my_table_id", force: true do |t|
+          t.integer "col_one"
+          t.string "col_two", limit: 128, null: false
+        end
+
+        remove_column("my_table", "col_two")
+        rename_column("my_table", "col_one", "col_three")
+
+        assert_equal 'my_table_id', connection.primary_key('my_table')
+      ensure
+        connection.drop_table(:my_table) rescue nil
+      end
+
+      def test_column_with_index
+        connection.create_table "my_table", force: true do |t|
+          t.string :item_number, index: true
+        end
+
+        assert connection.index_exists?("my_table", :item_number, name: :index_my_table_on_item_number)
+      ensure
+        connection.drop_table(:my_table) rescue nil
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/command_recorder_test.rb b/activerecord/test/cases/migration/command_recorder_test.rb
new file mode 100644
index 0000000000..e955beae1a
--- /dev/null
+++ b/activerecord/test/cases/migration/command_recorder_test.rb
@@ -0,0 +1,300 @@
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class CommandRecorderTest < ActiveRecord::TestCase
+      def setup
+        connection = ActiveRecord::Base.connection
+        @recorder  = CommandRecorder.new(connection)
+      end
+
+      def test_respond_to_delegates
+        recorder = CommandRecorder.new(Class.new {
+          def america; end
+        }.new)
+        assert recorder.respond_to?(:america)
+      end
+
+      def test_send_calls_super
+        assert_raises(NoMethodError) do
+          @recorder.send(:non_existing_method, :horses)
+        end
+      end
+
+      def test_send_delegates_to_record
+        recorder = CommandRecorder.new(Class.new {
+          def create_table(name); end
+        }.new)
+        assert recorder.respond_to?(:create_table), 'respond_to? create_table'
+        recorder.send(:create_table, :horses)
+        assert_equal [[:create_table, [:horses], nil]], recorder.commands
+      end
+
+      def test_unknown_commands_delegate
+        recorder = CommandRecorder.new(stub(:foo => 'bar'))
+        assert_equal 'bar', recorder.foo
+      end
+
+      def test_inverse_of_raise_exception_on_unknown_commands
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :execute, ['some sql']
+        end
+      end
+
+      def test_irreversible_commands_raise_exception
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.revert{ @recorder.execute 'some sql' }
+        end
+      end
+
+      def test_record
+        @recorder.record :create_table, [:system_settings]
+        assert_equal 1, @recorder.commands.length
+      end
+
+      def test_inverted_commands_are_reversed
+        @recorder.revert do
+          @recorder.record :create_table, [:hello]
+          @recorder.record :create_table, [:world]
+        end
+        tables = @recorder.commands.map{|_cmd, args, _block| args}
+        assert_equal [[:world], [:hello]], tables
+      end
+
+      def test_revert_order
+        block = Proc.new{|t| t.string :name }
+        @recorder.instance_eval do
+          create_table("apples", &block)
+          revert do
+            create_table("bananas", &block)
+            revert do
+              create_table("clementines", &block)
+              create_table("dates")
+            end
+            create_table("elderberries")
+          end
+          revert do
+            create_table("figs", &block)
+            create_table("grapes")
+          end
+        end
+        assert_equal [[:create_table, ["apples"], block], [:drop_table, ["elderberries"], nil],
+                      [:create_table, ["clementines"], block], [:create_table, ["dates"], nil],
+                      [:drop_table, ["bananas"], block], [:drop_table, ["grapes"], nil],
+                      [:drop_table, ["figs"], block]], @recorder.commands
+      end
+
+      def test_invert_change_table
+        @recorder.revert do
+          @recorder.change_table :fruits do |t|
+            t.string :name
+            t.rename :kind, :cultivar
+          end
+        end
+        assert_equal [
+          [:rename_column, [:fruits, :cultivar, :kind]],
+          [:remove_column, [:fruits, :name, :string, {}], nil],
+        ], @recorder.commands
+
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.revert do
+            @recorder.change_table :fruits do |t|
+              t.remove :kind
+            end
+          end
+        end
+      end
+
+      def test_invert_create_table
+        @recorder.revert do
+          @recorder.record :create_table, [:system_settings]
+        end
+        drop_table = @recorder.commands.first
+        assert_equal [:drop_table, [:system_settings], nil], drop_table
+      end
+
+      def test_invert_create_table_with_options_and_block
+        block = Proc.new{}
+        drop_table = @recorder.inverse_of :create_table, [:people_reminders, id: false], &block
+        assert_equal [:drop_table, [:people_reminders, id: false], block], drop_table
+      end
+
+      def test_invert_drop_table
+        block = Proc.new{}
+        create_table = @recorder.inverse_of :drop_table, [:people_reminders, id: false], &block
+        assert_equal [:create_table, [:people_reminders, id: false], block], create_table
+      end
+
+      def test_invert_drop_table_without_a_block_nor_option
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :drop_table, [:people_reminders]
+        end
+      end
+
+      def test_invert_create_join_table
+        drop_join_table = @recorder.inverse_of :create_join_table, [:musics, :artists]
+        assert_equal [:drop_join_table, [:musics, :artists], nil], drop_join_table
+      end
+
+      def test_invert_create_join_table_with_table_name
+        drop_join_table = @recorder.inverse_of :create_join_table, [:musics, :artists, table_name: :catalog]
+        assert_equal [:drop_join_table, [:musics, :artists, table_name: :catalog], nil], drop_join_table
+      end
+
+      def test_invert_drop_join_table
+        block = Proc.new{}
+        create_join_table = @recorder.inverse_of :drop_join_table, [:musics, :artists, table_name: :catalog], &block
+        assert_equal [:create_join_table, [:musics, :artists, table_name: :catalog], block], create_join_table
+      end
+
+      def test_invert_rename_table
+        rename = @recorder.inverse_of :rename_table, [:old, :new]
+        assert_equal [:rename_table, [:new, :old]], rename
+      end
+
+      def test_invert_add_column
+        remove = @recorder.inverse_of :add_column, [:table, :column, :type, {}]
+        assert_equal [:remove_column, [:table, :column, :type, {}], nil], remove
+      end
+
+      def test_invert_change_column
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :change_column, [:table, :column, :type, {}]
+        end
+      end
+
+      def test_invert_change_column_default
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :change_column_default, [:table, :column, 'default_value']
+        end
+      end
+
+      def test_invert_change_column_null
+        add = @recorder.inverse_of :change_column_null, [:table, :column, true]
+        assert_equal [:change_column_null, [:table, :column, false]], add
+      end
+
+      def test_invert_remove_column
+        add = @recorder.inverse_of :remove_column, [:table, :column, :type, {}]
+        assert_equal [:add_column, [:table, :column, :type, {}], nil], add
+      end
+
+      def test_invert_remove_column_without_type
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :remove_column, [:table, :column]
+        end
+      end
+
+      def test_invert_rename_column
+        rename = @recorder.inverse_of :rename_column, [:table, :old, :new]
+        assert_equal [:rename_column, [:table, :new, :old]], rename
+      end
+
+      def test_invert_add_index
+        remove = @recorder.inverse_of :add_index, [:table, [:one, :two]]
+        assert_equal [:remove_index, [:table, {column: [:one, :two]}]], remove
+      end
+
+      def test_invert_add_index_with_name
+        remove = @recorder.inverse_of :add_index, [:table, [:one, :two], name: "new_index"]
+        assert_equal [:remove_index, [:table, {name: "new_index"}]], remove
+      end
+
+      def test_invert_add_index_with_no_options
+        remove = @recorder.inverse_of :add_index, [:table, [:one, :two]]
+        assert_equal [:remove_index, [:table, {column: [:one, :two]}]], remove
+      end
+
+      def test_invert_remove_index
+        add = @recorder.inverse_of :remove_index, [:table, {column: [:one, :two], options: true}]
+        assert_equal [:add_index, [:table, [:one, :two], options: true]], add
+      end
+
+      def test_invert_remove_index_with_name
+        add = @recorder.inverse_of :remove_index, [:table, {column: [:one, :two], name: "new_index"}]
+        assert_equal [:add_index, [:table, [:one, :two], name: "new_index"]], add
+      end
+
+      def test_invert_remove_index_with_no_special_options
+        add = @recorder.inverse_of :remove_index, [:table, {column: [:one, :two]}]
+        assert_equal [:add_index, [:table, [:one, :two], {}]], add
+      end
+
+      def test_invert_remove_index_with_no_column
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.inverse_of :remove_index, [:table, name: "new_index"]
+        end
+      end
+
+      def test_invert_rename_index
+        rename = @recorder.inverse_of :rename_index, [:table, :old, :new]
+        assert_equal [:rename_index, [:table, :new, :old]], rename
+      end
+
+      def test_invert_add_timestamps
+        remove = @recorder.inverse_of :add_timestamps, [:table]
+        assert_equal [:remove_timestamps, [:table], nil], remove
+      end
+
+      def test_invert_remove_timestamps
+        add = @recorder.inverse_of :remove_timestamps, [:table]
+        assert_equal [:add_timestamps, [:table], nil], add
+      end
+
+      def test_invert_add_reference
+        remove = @recorder.inverse_of :add_reference, [:table, :taggable, { polymorphic: true }]
+        assert_equal [:remove_reference, [:table, :taggable, { polymorphic: true }], nil], remove
+      end
+
+      def test_invert_add_belongs_to_alias
+        remove = @recorder.inverse_of :add_belongs_to, [:table, :user]
+        assert_equal [:remove_reference, [:table, :user], nil], remove
+      end
+
+      def test_invert_remove_reference
+        add = @recorder.inverse_of :remove_reference, [:table, :taggable, { polymorphic: true }]
+        assert_equal [:add_reference, [:table, :taggable, { polymorphic: true }], nil], add
+      end
+
+      def test_invert_remove_belongs_to_alias
+        add = @recorder.inverse_of :remove_belongs_to, [:table, :user]
+        assert_equal [:add_reference, [:table, :user], nil], add
+      end
+
+      def test_invert_enable_extension
+        disable = @recorder.inverse_of :enable_extension, ['uuid-ossp']
+        assert_equal [:disable_extension, ['uuid-ossp'], nil], disable
+      end
+
+      def test_invert_disable_extension
+        enable = @recorder.inverse_of :disable_extension, ['uuid-ossp']
+        assert_equal [:enable_extension, ['uuid-ossp'], nil], enable
+      end
+
+      def test_invert_add_foreign_key
+        enable = @recorder.inverse_of :add_foreign_key, [:dogs, :people]
+        assert_equal [:remove_foreign_key, [:dogs, :people]], enable
+      end
+
+      def test_invert_add_foreign_key_with_column
+        enable = @recorder.inverse_of :add_foreign_key, [:dogs, :people, column: "owner_id"]
+        assert_equal [:remove_foreign_key, [:dogs, column: "owner_id"]], enable
+      end
+
+      def test_invert_add_foreign_key_with_column_and_name
+        enable = @recorder.inverse_of :add_foreign_key, [:dogs, :people, column: "owner_id", name: "fk"]
+        assert_equal [:remove_foreign_key, [:dogs, name: "fk"]], enable
+      end
+
+      def test_remove_foreign_key_is_irreversible
+        assert_raises ActiveRecord::IrreversibleMigration do
+          @recorder.inverse_of :remove_foreign_key, [:dogs, column: "owner_id"]
+        end
+
+        assert_raises ActiveRecord::IrreversibleMigration do
+          @recorder.inverse_of :remove_foreign_key, [:dogs, name: "fk"]
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/create_join_table_test.rb b/activerecord/test/cases/migration/create_join_table_test.rb
new file mode 100644
index 0000000000..bea9d6b2c9
--- /dev/null
+++ b/activerecord/test/cases/migration/create_join_table_test.rb
@@ -0,0 +1,148 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class Migration
+    class CreateJoinTableTest < ActiveRecord::TestCase
+      attr_reader :connection
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+      end
+
+      teardown do
+        %w(artists_musics musics_videos catalog).each do |table_name|
+          connection.drop_table table_name if connection.tables.include?(table_name)
+        end
+      end
+
+      def test_create_join_table
+        connection.create_join_table :artists, :musics
+
+        assert_equal %w(artist_id music_id), connection.columns(:artists_musics).map(&:name).sort
+      end
+
+      def test_create_join_table_set_not_null_by_default
+        connection.create_join_table :artists, :musics
+
+        assert_equal [false, false], connection.columns(:artists_musics).map(&:null)
+      end
+
+      def test_create_join_table_with_strings
+        connection.create_join_table 'artists', 'musics'
+
+        assert_equal %w(artist_id music_id), connection.columns(:artists_musics).map(&:name).sort
+      end
+
+      def test_create_join_table_with_symbol_and_string
+        connection.create_join_table :artists, 'musics'
+
+        assert_equal %w(artist_id music_id), connection.columns(:artists_musics).map(&:name).sort
+      end
+
+      def test_create_join_table_with_the_proper_order
+        connection.create_join_table :videos, :musics
+
+        assert_equal %w(music_id video_id), connection.columns(:musics_videos).map(&:name).sort
+      end
+
+      def test_create_join_table_with_the_table_name
+        connection.create_join_table :artists, :musics, table_name: :catalog
+
+        assert_equal %w(artist_id music_id), connection.columns(:catalog).map(&:name).sort
+      end
+
+      def test_create_join_table_with_the_table_name_as_string
+        connection.create_join_table :artists, :musics, table_name: 'catalog'
+
+        assert_equal %w(artist_id music_id), connection.columns(:catalog).map(&:name).sort
+      end
+
+      def test_create_join_table_with_column_options
+        connection.create_join_table :artists, :musics, column_options: {null: true}
+
+        assert_equal [true, true], connection.columns(:artists_musics).map(&:null)
+      end
+
+      def test_create_join_table_without_indexes
+        connection.create_join_table :artists, :musics
+
+        assert connection.indexes(:artists_musics).blank?
+      end
+
+      def test_create_join_table_with_index
+        connection.create_join_table :artists, :musics do |t|
+          t.index [:artist_id, :music_id]
+        end
+
+        assert_equal [%w(artist_id music_id)], connection.indexes(:artists_musics).map(&:columns)
+      end
+
+      def test_drop_join_table
+        connection.create_join_table :artists, :musics
+        connection.drop_join_table :artists, :musics
+
+        assert !connection.tables.include?('artists_musics')
+      end
+
+      def test_drop_join_table_with_strings
+        connection.create_join_table :artists, :musics
+        connection.drop_join_table 'artists', 'musics'
+
+        assert !connection.tables.include?('artists_musics')
+      end
+
+      def test_drop_join_table_with_the_proper_order
+        connection.create_join_table :videos, :musics
+        connection.drop_join_table :videos, :musics
+
+        assert !connection.tables.include?('musics_videos')
+      end
+
+      def test_drop_join_table_with_the_table_name
+        connection.create_join_table :artists, :musics, table_name: :catalog
+        connection.drop_join_table :artists, :musics, table_name: :catalog
+
+        assert !connection.tables.include?('catalog')
+      end
+
+      def test_drop_join_table_with_the_table_name_as_string
+        connection.create_join_table :artists, :musics, table_name: 'catalog'
+        connection.drop_join_table :artists, :musics, table_name: 'catalog'
+
+        assert !connection.tables.include?('catalog')
+      end
+
+      def test_drop_join_table_with_column_options
+        connection.create_join_table :artists, :musics, column_options: {null: true}
+        connection.drop_join_table :artists, :musics, column_options: {null: true}
+
+        assert !connection.tables.include?('artists_musics')
+      end
+
+      def test_create_and_drop_join_table_with_common_prefix
+        with_table_cleanup do
+          connection.create_join_table 'audio_artists', 'audio_musics'
+          assert_includes connection.tables, 'audio_artists_musics'
+
+          connection.drop_join_table 'audio_artists', 'audio_musics'
+          assert !connection.tables.include?('audio_artists_musics'), "Should have dropped join table, but didn't"
+        end
+      end
+
+      private
+
+        def with_table_cleanup
+          tables_before = connection.tables
+
+          yield
+        ensure
+          tables_after = connection.tables - tables_before
+
+          tables_after.each do |table|
+            connection.execute "DROP TABLE #{table}"
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/foreign_key_test.rb b/activerecord/test/cases/migration/foreign_key_test.rb
new file mode 100644
index 0000000000..c985092b4c
--- /dev/null
+++ b/activerecord/test/cases/migration/foreign_key_test.rb
@@ -0,0 +1,242 @@
+require 'cases/helper'
+require 'support/ddl_helper'
+require 'support/schema_dumping_helper'
+
+if ActiveRecord::Base.connection.supports_foreign_keys?
+module ActiveRecord
+  class Migration
+    class ForeignKeyTest < ActiveRecord::TestCase
+      include DdlHelper
+      include SchemaDumpingHelper
+
+      class Rocket < ActiveRecord::Base
+      end
+
+      class Astronaut < ActiveRecord::Base
+      end
+
+      setup do
+        @connection = ActiveRecord::Base.connection
+        @connection.create_table "rockets" do |t|
+          t.string :name
+        end
+
+        @connection.create_table "astronauts" do |t|
+          t.string :name
+          t.references :rocket
+        end
+      end
+
+      teardown do
+        if defined?(@connection)
+          @connection.execute "DROP TABLE IF EXISTS astronauts"
+          @connection.execute "DROP TABLE IF EXISTS rockets"
+        end
+      end
+
+      def test_foreign_keys
+        foreign_keys = @connection.foreign_keys("fk_test_has_fk")
+        assert_equal 1, foreign_keys.size
+
+        fk = foreign_keys.first
+        assert_equal "fk_test_has_fk", fk.from_table
+        assert_equal "fk_test_has_pk", fk.to_table
+        assert_equal "fk_id", fk.column
+        assert_equal "pk_id", fk.primary_key
+        assert_equal "fk_name", fk.name
+      end
+
+      def test_add_foreign_key_inferes_column
+        @connection.add_foreign_key :astronauts, :rockets
+
+        foreign_keys = @connection.foreign_keys("astronauts")
+        assert_equal 1, foreign_keys.size
+
+        fk = foreign_keys.first
+        assert_equal "astronauts", fk.from_table
+        assert_equal "rockets", fk.to_table
+        assert_equal "rocket_id", fk.column
+        assert_equal "id", fk.primary_key
+        assert_match(/^fk_rails_.{10}$/, fk.name)
+      end
+
+      def test_add_foreign_key_with_column
+        @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id"
+
+        foreign_keys = @connection.foreign_keys("astronauts")
+        assert_equal 1, foreign_keys.size
+
+        fk = foreign_keys.first
+        assert_equal "astronauts", fk.from_table
+        assert_equal "rockets", fk.to_table
+        assert_equal "rocket_id", fk.column
+        assert_equal "id", fk.primary_key
+        assert_match(/^fk_rails_.{10}$/, fk.name)
+      end
+
+      def test_add_foreign_key_with_non_standard_primary_key
+        with_example_table @connection, "space_shuttles", "pk integer PRIMARY KEY" do
+          @connection.add_foreign_key(:astronauts, :space_shuttles,
+                                      column: "rocket_id", primary_key: "pk", name: "custom_pk")
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal "astronauts", fk.from_table
+          assert_equal "space_shuttles", fk.to_table
+          assert_equal "pk", fk.primary_key
+
+          @connection.remove_foreign_key :astronauts, name: "custom_pk"
+        end
+      end
+
+      def test_add_on_delete_restrict_foreign_key
+        @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :restrict
+
+        foreign_keys = @connection.foreign_keys("astronauts")
+        assert_equal 1, foreign_keys.size
+
+        fk = foreign_keys.first
+        if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+          # ON DELETE RESTRICT is the default on MySQL
+          assert_equal nil, fk.on_delete
+        else
+          assert_equal :restrict, fk.on_delete
+        end
+      end
+
+      def test_add_on_delete_cascade_foreign_key
+        @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :cascade
+
+        foreign_keys = @connection.foreign_keys("astronauts")
+        assert_equal 1, foreign_keys.size
+
+        fk = foreign_keys.first
+        assert_equal :cascade, fk.on_delete
+      end
+
+      def test_add_on_delete_nullify_foreign_key
+        @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :nullify
+
+        foreign_keys = @connection.foreign_keys("astronauts")
+        assert_equal 1, foreign_keys.size
+
+        fk = foreign_keys.first
+        assert_equal :nullify, fk.on_delete
+      end
+
+      def test_on_update_and_on_delete_raises_with_invalid_values
+        assert_raises ArgumentError do
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :invalid
+        end
+
+        assert_raises ArgumentError do
+          @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_update: :invalid
+        end
+      end
+
+      def test_add_foreign_key_with_on_update
+        @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_update: :nullify
+
+        foreign_keys = @connection.foreign_keys("astronauts")
+        assert_equal 1, foreign_keys.size
+
+        fk = foreign_keys.first
+        assert_equal :nullify, fk.on_update
+      end
+
+      def test_remove_foreign_key_inferes_column
+        @connection.add_foreign_key :astronauts, :rockets
+
+        assert_equal 1, @connection.foreign_keys("astronauts").size
+        @connection.remove_foreign_key :astronauts, :rockets
+        assert_equal [], @connection.foreign_keys("astronauts")
+      end
+
+      def test_remove_foreign_key_by_column
+        @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id"
+
+        assert_equal 1, @connection.foreign_keys("astronauts").size
+        @connection.remove_foreign_key :astronauts, column: "rocket_id"
+        assert_equal [], @connection.foreign_keys("astronauts")
+      end
+
+      def test_remove_foreign_key_by_name
+        @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", name: "fancy_named_fk"
+
+        assert_equal 1, @connection.foreign_keys("astronauts").size
+        @connection.remove_foreign_key :astronauts, name: "fancy_named_fk"
+        assert_equal [], @connection.foreign_keys("astronauts")
+      end
+
+      def test_remove_foreign_non_existing_foreign_key_raises
+        assert_raises ArgumentError do
+          @connection.remove_foreign_key :astronauts, :rockets
+        end
+      end
+
+      def test_schema_dumping
+        @connection.add_foreign_key :astronauts, :rockets
+        output = dump_table_schema "astronauts"
+        assert_match %r{\s+add_foreign_key "astronauts", "rockets"$}, output
+      end
+
+      def test_schema_dumping_with_options
+        output = dump_table_schema "fk_test_has_fk"
+        assert_match %r{\s+add_foreign_key "fk_test_has_fk", "fk_test_has_pk", column: "fk_id", primary_key: "pk_id", name: "fk_name"$}, output
+      end
+
+      def test_schema_dumping_on_delete_and_on_update_options
+        @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :nullify, on_update: :cascade
+
+        output = dump_table_schema "astronauts"
+        assert_match %r{\s+add_foreign_key "astronauts",.+on_update: :cascade,.+on_delete: :nullify$}, output
+      end
+
+      class CreateCitiesAndHousesMigration < ActiveRecord::Migration
+        def change
+          create_table("cities") { |t| }
+
+          create_table("houses") do |t|
+            t.column :city_id, :integer
+          end
+          add_foreign_key :houses, :cities, column: "city_id"
+        end
+      end
+
+      def test_add_foreign_key_is_reversible
+        migration = CreateCitiesAndHousesMigration.new
+        silence_stream($stdout) { migration.migrate(:up) }
+        assert_equal 1, @connection.foreign_keys("houses").size
+      ensure
+        silence_stream($stdout) { migration.migrate(:down) }
+      end
+    end
+  end
+end
+else
+module ActiveRecord
+  class Migration
+    class NoForeignKeySupportTest < ActiveRecord::TestCase
+      setup do
+        @connection = ActiveRecord::Base.connection
+      end
+
+      def test_add_foreign_key_should_be_noop
+        @connection.add_foreign_key :clubs, :categories
+      end
+
+      def test_remove_foreign_key_should_be_noop
+        @connection.remove_foreign_key :clubs, :categories
+      end
+
+      def test_foreign_keys_should_raise_not_implemented
+        assert_raises NotImplementedError do
+          @connection.foreign_keys("clubs")
+        end
+      end
+    end
+  end
+end
+end
diff --git a/activerecord/test/cases/migration/helper.rb b/activerecord/test/cases/migration/helper.rb
new file mode 100644
index 0000000000..e28feedcf9
--- /dev/null
+++ b/activerecord/test/cases/migration/helper.rb
@@ -0,0 +1,43 @@
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class << self; attr_accessor :message_count; end
+    self.message_count = 0
+
+    def puts(text="")
+      ActiveRecord::Migration.message_count += 1
+    end
+
+    module TestHelper
+      attr_reader :connection, :table_name
+
+      CONNECTION_METHODS = %w[add_column remove_column rename_column add_index change_column rename_table column_exists? index_exists? add_reference add_belongs_to remove_reference remove_references remove_belongs_to]
+
+      class TestModel < ActiveRecord::Base
+        self.table_name = :test_models
+      end
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        connection.create_table :test_models do |t|
+          t.timestamps
+        end
+
+        TestModel.reset_column_information
+      end
+
+      def teardown
+        super
+        TestModel.reset_table_name
+        TestModel.reset_sequence_name
+        connection.drop_table :test_models rescue nil
+      end
+
+      private
+
+      delegate(*CONNECTION_METHODS, to: :connection)
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/index_test.rb b/activerecord/test/cases/migration/index_test.rb
new file mode 100644
index 0000000000..93c3bfae7a
--- /dev/null
+++ b/activerecord/test/cases/migration/index_test.rb
@@ -0,0 +1,188 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class Migration
+    class IndexTest < ActiveRecord::TestCase
+      attr_reader :connection, :table_name
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @table_name = :testings
+
+        connection.create_table table_name do |t|
+          t.column :foo, :string, :limit => 100
+          t.column :bar, :string, :limit => 100
+
+          t.string :first_name
+          t.string :last_name, :limit => 100
+          t.string :key,       :limit => 100
+          t.boolean :administrator
+        end
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+        ActiveRecord::Base.primary_key_prefix_type = nil
+      end
+
+      def test_rename_index
+        # keep the names short to make Oracle and similar behave
+        connection.add_index(table_name, [:foo], :name => 'old_idx')
+        connection.rename_index(table_name, 'old_idx', 'new_idx')
+
+        # if the adapter doesn't support the indexes call, pick defaults that let the test pass
+        assert_not connection.index_name_exists?(table_name, 'old_idx', false)
+        assert connection.index_name_exists?(table_name, 'new_idx', true)
+      end
+
+      def test_double_add_index
+        connection.add_index(table_name, [:foo], :name => 'some_idx')
+        assert_raises(ArgumentError) {
+          connection.add_index(table_name, [:foo], :name => 'some_idx')
+        }
+      end
+
+      def test_remove_nonexistent_index
+        assert_raise(ArgumentError) { connection.remove_index(table_name, "no_such_index") }
+      end
+
+      def test_add_index_works_with_long_index_names
+        connection.add_index(table_name, "foo", name: good_index_name)
+
+        assert connection.index_name_exists?(table_name, good_index_name, false)
+        connection.remove_index(table_name, name: good_index_name)
+      end
+
+      def test_add_index_does_not_accept_too_long_index_names
+        too_long_index_name = good_index_name + 'x'
+
+        e = assert_raises(ArgumentError) {
+          connection.add_index(table_name, "foo", name: too_long_index_name)
+        }
+        assert_match(/too long; the limit is #{connection.allowed_index_name_length} characters/, e.message)
+
+        assert_not connection.index_name_exists?(table_name, too_long_index_name, false)
+        connection.add_index(table_name, "foo", :name => good_index_name)
+      end
+
+      def test_internal_index_with_name_matching_database_limit
+        good_index_name = 'x' * connection.index_name_length
+        connection.add_index(table_name, "foo", name: good_index_name, internal: true)
+
+        assert connection.index_name_exists?(table_name, good_index_name, false)
+        connection.remove_index(table_name, name: good_index_name)
+      end
+
+      def test_index_symbol_names
+        connection.add_index table_name, :foo, :name => :symbol_index_name
+        assert connection.index_exists?(table_name, :foo, :name => :symbol_index_name)
+
+        connection.remove_index table_name, :name => :symbol_index_name
+        assert_not connection.index_exists?(table_name, :foo, :name => :symbol_index_name)
+      end
+
+      def test_index_exists
+        connection.add_index :testings, :foo
+
+        assert connection.index_exists?(:testings, :foo)
+        assert !connection.index_exists?(:testings, :bar)
+      end
+
+      def test_index_exists_on_multiple_columns
+        connection.add_index :testings, [:foo, :bar]
+
+        assert connection.index_exists?(:testings, [:foo, :bar])
+      end
+
+      def test_valid_index_options
+        assert_raise ArgumentError do
+          connection.add_index :testings, :foo, unqiue: true
+        end
+      end
+
+      def test_unique_index_exists
+        connection.add_index :testings, :foo, :unique => true
+
+        assert connection.index_exists?(:testings, :foo, :unique => true)
+      end
+
+      def test_named_index_exists
+        connection.add_index :testings, :foo, :name => "custom_index_name"
+
+        assert connection.index_exists?(:testings, :foo, :name => "custom_index_name")
+      end
+
+      def test_add_index_attribute_length_limit
+        connection.add_index :testings, [:foo, :bar], :length => {:foo => 10, :bar => nil}
+
+        assert connection.index_exists?(:testings, [:foo, :bar])
+      end
+
+      def test_add_index
+        connection.add_index("testings", "last_name")
+        connection.remove_index("testings", "last_name")
+
+        connection.add_index("testings", ["last_name", "first_name"])
+        connection.remove_index("testings", :column => ["last_name", "first_name"])
+
+        # Oracle adapter cannot have specified index name larger than 30 characters
+        # Oracle adapter is shortening index name when just column list is given
+        unless current_adapter?(:OracleAdapter)
+          connection.add_index("testings", ["last_name", "first_name"])
+          connection.remove_index("testings", :name => :index_testings_on_last_name_and_first_name)
+          connection.add_index("testings", ["last_name", "first_name"])
+          connection.remove_index("testings", "last_name_and_first_name")
+        end
+        connection.add_index("testings", ["last_name", "first_name"])
+        connection.remove_index("testings", ["last_name", "first_name"])
+
+        connection.add_index("testings", ["last_name"], :length => 10)
+        connection.remove_index("testings", "last_name")
+
+        connection.add_index("testings", ["last_name"], :length => {:last_name => 10})
+        connection.remove_index("testings", ["last_name"])
+
+        connection.add_index("testings", ["last_name", "first_name"], :length => 10)
+        connection.remove_index("testings", ["last_name", "first_name"])
+
+        connection.add_index("testings", ["last_name", "first_name"], :length => {:last_name => 10, :first_name => 20})
+        connection.remove_index("testings", ["last_name", "first_name"])
+
+        connection.add_index("testings", ["key"], :name => "key_idx", :unique => true)
+        connection.remove_index("testings", :name => "key_idx", :unique => true)
+
+        connection.add_index("testings", %w(last_name first_name administrator), :name => "named_admin")
+        connection.remove_index("testings", :name => "named_admin")
+
+        # Selected adapters support index sort order
+        if current_adapter?(:SQLite3Adapter, :MysqlAdapter, :Mysql2Adapter, :PostgreSQLAdapter)
+          connection.add_index("testings", ["last_name"], :order => {:last_name => :desc})
+          connection.remove_index("testings", ["last_name"])
+          connection.add_index("testings", ["last_name", "first_name"], :order => {:last_name => :desc})
+          connection.remove_index("testings", ["last_name", "first_name"])
+          connection.add_index("testings", ["last_name", "first_name"], :order => {:last_name => :desc, :first_name => :asc})
+          connection.remove_index("testings", ["last_name", "first_name"])
+          connection.add_index("testings", ["last_name", "first_name"], :order => :desc)
+          connection.remove_index("testings", ["last_name", "first_name"])
+        end
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_add_partial_index
+          connection.add_index("testings", "last_name", :where => "first_name = 'john doe'")
+          assert connection.index_exists?("testings", "last_name")
+
+          connection.remove_index("testings", "last_name")
+          assert !connection.index_exists?("testings", "last_name")
+        end
+      end
+
+      private
+        def good_index_name
+          'x' * connection.allowed_index_name_length
+        end
+
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/logger_test.rb b/activerecord/test/cases/migration/logger_test.rb
new file mode 100644
index 0000000000..319d3e1af3
--- /dev/null
+++ b/activerecord/test/cases/migration/logger_test.rb
@@ -0,0 +1,36 @@
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class LoggerTest < ActiveRecord::TestCase
+      # MySQL can't roll back ddl changes
+      self.use_transactional_fixtures = false
+
+      Migration = Struct.new(:name, :version) do
+        def disable_ddl_transaction; false end
+        def migrate direction
+          # do nothing
+        end
+      end
+
+      def setup
+        super
+        ActiveRecord::SchemaMigration.create_table
+        ActiveRecord::SchemaMigration.delete_all
+      end
+
+      teardown do
+        ActiveRecord::SchemaMigration.drop_table
+      end
+
+      def test_migration_should_be_run_without_logger
+        previous_logger = ActiveRecord::Base.logger
+        ActiveRecord::Base.logger = nil
+        migrations = [Migration.new('a', 1), Migration.new('b', 2), Migration.new('c', 3)]
+        ActiveRecord::Migrator.new(:up, migrations).migrate
+      ensure
+        ActiveRecord::Base.logger = previous_logger
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/pending_migrations_test.rb b/activerecord/test/cases/migration/pending_migrations_test.rb
new file mode 100644
index 0000000000..7afac83bd2
--- /dev/null
+++ b/activerecord/test/cases/migration/pending_migrations_test.rb
@@ -0,0 +1,53 @@
+require 'cases/helper'
+require "minitest/mock"
+
+module ActiveRecord
+  class Migration
+    class PendingMigrationsTest < ActiveRecord::TestCase
+      def setup
+        super
+        @connection = Minitest::Mock.new
+        @app = Minitest::Mock.new
+        conn = @connection
+        @pending = Class.new(CheckPending) {
+          define_method(:connection) { conn }
+        }.new(@app)
+        @pending.instance_variable_set :@last_check, -1 # Force checking
+      end
+
+      def teardown
+        assert @connection.verify
+        assert @app.verify
+        super
+      end
+
+      def test_errors_if_pending
+        @connection.expect :supports_migrations?, true
+
+        ActiveRecord::Migrator.stub :needs_migration?, true do
+          assert_raise ActiveRecord::PendingMigrationError do
+            @pending.call(nil)
+          end
+        end
+      end
+
+      def test_checks_if_supported
+        @connection.expect :supports_migrations?, true
+        @app.expect :call, nil, [:foo]
+
+        ActiveRecord::Migrator.stub :needs_migration?, false do
+          @pending.call(:foo)
+        end
+      end
+
+      def test_doesnt_check_if_unsupported
+        @connection.expect :supports_migrations?, false
+        @app.expect :call, nil, [:foo]
+
+        ActiveRecord::Migrator.stub :needs_migration?, true do
+          @pending.call(:foo)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/references_index_test.rb b/activerecord/test/cases/migration/references_index_test.rb
new file mode 100644
index 0000000000..4485701a4e
--- /dev/null
+++ b/activerecord/test/cases/migration/references_index_test.rb
@@ -0,0 +1,101 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class Migration
+    class ReferencesIndexTest < ActiveRecord::TestCase
+      attr_reader :connection, :table_name
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @table_name = :testings
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+      end
+
+      def test_creates_index
+        connection.create_table table_name do |t|
+          t.references :foo, :index => true
+        end
+
+        assert connection.index_exists?(table_name, :foo_id, :name => :index_testings_on_foo_id)
+      end
+
+      def test_does_not_create_index
+        connection.create_table table_name do |t|
+          t.references :foo
+        end
+
+        assert_not connection.index_exists?(table_name, :foo_id, :name => :index_testings_on_foo_id)
+      end
+
+      def test_does_not_create_index_explicit
+        connection.create_table table_name do |t|
+          t.references :foo, :index => false
+        end
+
+        assert_not connection.index_exists?(table_name, :foo_id, :name => :index_testings_on_foo_id)
+      end
+
+      def test_creates_index_with_options
+        connection.create_table table_name do |t|
+          t.references :foo, :index => {:name => :index_testings_on_yo_momma}
+          t.references :bar, :index => {:unique => true}
+        end
+
+        assert connection.index_exists?(table_name, :foo_id, :name => :index_testings_on_yo_momma)
+        assert connection.index_exists?(table_name, :bar_id, :name => :index_testings_on_bar_id, :unique => true)
+      end
+
+      unless current_adapter? :OracleAdapter
+        def test_creates_polymorphic_index
+          connection.create_table table_name do |t|
+            t.references :foo, :polymorphic => true, :index => true
+          end
+
+          assert connection.index_exists?(table_name, [:foo_id, :foo_type], :name => :index_testings_on_foo_id_and_foo_type)
+        end
+      end
+
+      def test_creates_index_for_existing_table
+        connection.create_table table_name
+        connection.change_table table_name do |t|
+          t.references :foo, :index => true
+        end
+
+        assert connection.index_exists?(table_name, :foo_id, :name => :index_testings_on_foo_id)
+      end
+
+      def test_does_not_create_index_for_existing_table
+        connection.create_table table_name
+        connection.change_table table_name do |t|
+          t.references :foo
+        end
+
+        assert_not connection.index_exists?(table_name, :foo_id, :name => :index_testings_on_foo_id)
+      end
+
+      def test_does_not_create_index_for_existing_table_explicit
+        connection.create_table table_name
+        connection.change_table table_name do |t|
+          t.references :foo, :index => false
+        end
+
+        assert_not connection.index_exists?(table_name, :foo_id, :name => :index_testings_on_foo_id)
+      end
+
+      unless current_adapter? :OracleAdapter
+        def test_creates_polymorphic_index_for_existing_table
+          connection.create_table table_name
+          connection.change_table table_name do |t|
+            t.references :foo, :polymorphic => true, :index => true
+          end
+
+          assert connection.index_exists?(table_name, [:foo_id, :foo_type], :name => :index_testings_on_foo_id_and_foo_type)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/references_statements_test.rb b/activerecord/test/cases/migration/references_statements_test.rb
new file mode 100644
index 0000000000..b8b4fa1135
--- /dev/null
+++ b/activerecord/test/cases/migration/references_statements_test.rb
@@ -0,0 +1,116 @@
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class ReferencesStatementsTest < ActiveRecord::TestCase
+      include ActiveRecord::Migration::TestHelper
+
+      self.use_transactional_fixtures = false
+
+      def setup
+        super
+        @table_name = :test_models
+
+        add_column table_name, :supplier_id, :integer
+        add_index table_name, :supplier_id
+      end
+
+      def test_creates_reference_id_column
+        add_reference table_name, :user
+        assert column_exists?(table_name, :user_id, :integer)
+      end
+
+      def test_does_not_create_reference_type_column
+        add_reference table_name, :taggable
+        assert_not column_exists?(table_name, :taggable_type, :string)
+      end
+
+      def test_creates_reference_type_column
+        add_reference table_name, :taggable, polymorphic: true
+        assert column_exists?(table_name, :taggable_type, :string)
+      end
+
+      def test_creates_reference_id_index
+        add_reference table_name, :user, index: true
+        assert index_exists?(table_name, :user_id)
+      end
+
+      def test_does_not_create_reference_id_index
+        add_reference table_name, :user
+        assert_not index_exists?(table_name, :user_id)
+      end
+
+      def test_creates_polymorphic_index
+        add_reference table_name, :taggable, polymorphic: true, index: true
+        assert index_exists?(table_name, [:taggable_id, :taggable_type])
+      end
+
+      def test_creates_reference_type_column_with_default
+        add_reference table_name, :taggable, polymorphic: { default: 'Photo' }, index: true
+        assert column_exists?(table_name, :taggable_type, :string, default: 'Photo')
+      end
+
+      def test_creates_named_index
+        add_reference table_name, :tag, index: { name: 'index_taggings_on_tag_id' }
+        assert index_exists?(table_name, :tag_id, name: 'index_taggings_on_tag_id')
+      end
+
+      def test_creates_reference_id_with_specified_type
+        add_reference table_name, :user, type: :string
+        assert column_exists?(table_name, :user_id, :string)
+      end
+
+      def test_deletes_reference_id_column
+        remove_reference table_name, :supplier
+        assert_not column_exists?(table_name, :supplier_id, :integer)
+      end
+
+      def test_deletes_reference_id_index
+        remove_reference table_name, :supplier
+        assert_not index_exists?(table_name, :supplier_id)
+      end
+
+      def test_does_not_delete_reference_type_column
+        with_polymorphic_column do
+          remove_reference table_name, :supplier
+
+          assert_not column_exists?(table_name, :supplier_id, :integer)
+          assert column_exists?(table_name, :supplier_type, :string)
+        end
+      end
+
+      def test_deletes_reference_type_column
+        with_polymorphic_column do
+          remove_reference table_name, :supplier, polymorphic: true
+          assert_not column_exists?(table_name, :supplier_type, :string)
+        end
+      end
+
+      def test_deletes_polymorphic_index
+        with_polymorphic_column do
+          remove_reference table_name, :supplier, polymorphic: true
+          assert_not index_exists?(table_name, [:supplier_id, :supplier_type])
+        end
+      end
+
+      def test_add_belongs_to_alias
+        add_belongs_to table_name, :user
+        assert column_exists?(table_name, :user_id, :integer)
+      end
+
+      def test_remove_belongs_to_alias
+        remove_belongs_to table_name, :supplier
+        assert_not column_exists?(table_name, :supplier_id, :integer)
+      end
+
+      private
+
+      def with_polymorphic_column
+        add_column table_name, :supplier_type, :string
+        add_index table_name, [:supplier_id, :supplier_type]
+
+        yield
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/rename_table_test.rb b/activerecord/test/cases/migration/rename_table_test.rb
new file mode 100644
index 0000000000..ba39fb1dec
--- /dev/null
+++ b/activerecord/test/cases/migration/rename_table_test.rb
@@ -0,0 +1,92 @@
+require "cases/migration/helper"
+
+module ActiveRecord
+  class Migration
+    class RenameTableTest < ActiveRecord::TestCase
+      include ActiveRecord::Migration::TestHelper
+
+      self.use_transactional_fixtures = false
+
+      def setup
+        super
+        add_column 'test_models', :url, :string
+        remove_column 'test_models', :created_at
+        remove_column 'test_models', :updated_at
+      end
+
+      def teardown
+        rename_table :octopi, :test_models if connection.table_exists? :octopi
+        super
+      end
+
+      if current_adapter?(:SQLite3Adapter)
+        def test_rename_table_for_sqlite_should_work_with_reserved_words
+          renamed = false
+
+          add_column :test_models, :url, :string
+          connection.rename_table :references, :old_references
+          connection.rename_table :test_models, :references
+
+          renamed = true
+
+          # Using explicit id in insert for compatibility across all databases
+          connection.execute "INSERT INTO 'references' (url, created_at, updated_at) VALUES ('http://rubyonrails.com', 0, 0)"
+          assert_equal 'http://rubyonrails.com', connection.select_value("SELECT url FROM 'references' WHERE id=1")
+        ensure
+          return unless renamed
+          connection.rename_table :references, :test_models
+          connection.rename_table :old_references, :references
+        end
+      end
+
+      def test_rename_table
+        rename_table :test_models, :octopi
+
+        connection.execute "INSERT INTO octopi (#{connection.quote_column_name('id')}, #{connection.quote_column_name('url')}) VALUES (1, 'http://www.foreverflying.com/octopus-black7.jpg')"
+
+        assert_equal 'http://www.foreverflying.com/octopus-black7.jpg', connection.select_value("SELECT url FROM octopi WHERE id=1")
+      end
+
+      def test_rename_table_with_an_index
+        add_index :test_models, :url
+
+        rename_table :test_models, :octopi
+
+        connection.execute "INSERT INTO octopi (#{connection.quote_column_name('id')}, #{connection.quote_column_name('url')}) VALUES (1, 'http://www.foreverflying.com/octopus-black7.jpg')"
+
+        assert_equal 'http://www.foreverflying.com/octopus-black7.jpg', connection.select_value("SELECT url FROM octopi WHERE id=1")
+        index = connection.indexes(:octopi).first
+        assert index.columns.include?("url")
+        assert_equal 'index_octopi_on_url', index.name
+      end
+
+      def test_rename_table_does_not_rename_custom_named_index
+        add_index :test_models, :url, name: 'special_url_idx'
+
+        rename_table :test_models, :octopi
+
+        assert_equal ['special_url_idx'], connection.indexes(:octopi).map(&:name)
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_rename_table_for_postgresql_should_also_rename_default_sequence
+          rename_table :test_models, :octopi
+
+          pk, seq = connection.pk_and_sequence_for('octopi')
+
+          assert_equal ConnectionAdapters::PostgreSQL::Name.new("public", "octopi_#{pk}_seq"), seq
+        end
+
+        def test_renaming_table_doesnt_attempt_to_rename_non_existent_sequences
+          enable_uuid_ossp!(connection)
+          connection.create_table :cats, id: :uuid
+          assert_nothing_raised { rename_table :cats, :felines }
+          assert connection.table_exists? :felines
+        ensure
+          connection.drop_table :cats if connection.table_exists? :cats
+          connection.drop_table :felines if connection.table_exists? :felines
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration/table_and_index_test.rb b/activerecord/test/cases/migration/table_and_index_test.rb
new file mode 100644
index 0000000000..8fd770abd1
--- /dev/null
+++ b/activerecord/test/cases/migration/table_and_index_test.rb
@@ -0,0 +1,24 @@
+require "cases/helper"
+
+module ActiveRecord
+  class Migration
+    class TableAndIndexTest < ActiveRecord::TestCase
+      def test_add_schema_info_respects_prefix_and_suffix
+        conn = ActiveRecord::Base.connection
+
+        conn.drop_table(ActiveRecord::Migrator.schema_migrations_table_name) if conn.table_exists?(ActiveRecord::Migrator.schema_migrations_table_name)
+        # Use shorter prefix and suffix as in Oracle database identifier cannot be larger than 30 characters
+        ActiveRecord::Base.table_name_prefix = 'p_'
+        ActiveRecord::Base.table_name_suffix = '_s'
+        conn.drop_table(ActiveRecord::Migrator.schema_migrations_table_name) if conn.table_exists?(ActiveRecord::Migrator.schema_migrations_table_name)
+
+        conn.initialize_schema_migrations_table
+
+        assert_equal "p_unique_schema_migrations_s", conn.indexes(ActiveRecord::Migrator.schema_migrations_table_name)[0][:name]
+      ensure
+        ActiveRecord::Base.table_name_prefix = ""
+        ActiveRecord::Base.table_name_suffix = ""
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migration_test.rb b/activerecord/test/cases/migration_test.rb
new file mode 100644
index 0000000000..ef3f073472
--- /dev/null
+++ b/activerecord/test/cases/migration_test.rb
@@ -0,0 +1,908 @@
+require "cases/helper"
+require "cases/migration/helper"
+require 'bigdecimal/util'
+
+require 'models/person'
+require 'models/topic'
+require 'models/developer'
+
+require MIGRATIONS_ROOT + "/valid/2_we_need_reminders"
+require MIGRATIONS_ROOT + "/rename/1_we_need_things"
+require MIGRATIONS_ROOT + "/rename/2_rename_things"
+require MIGRATIONS_ROOT + "/decimal/1_give_me_big_numbers"
+
+class BigNumber < ActiveRecord::Base
+  unless current_adapter?(:PostgreSQLAdapter, :SQLite3Adapter)
+    attribute :value_of_e, Type::Integer.new
+  end
+  attribute :world_population, Type::Integer.new
+  attribute :my_house_population, Type::Integer.new
+end
+
+class Reminder < ActiveRecord::Base; end
+
+class Thing < ActiveRecord::Base; end
+
+class MigrationTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  fixtures :people
+
+  def setup
+    super
+    %w(reminders people_reminders prefix_reminders_suffix p_things_s).each do |table|
+      Reminder.connection.drop_table(table) rescue nil
+    end
+    Reminder.reset_column_information
+    ActiveRecord::Migration.verbose = true
+    ActiveRecord::Migration.message_count = 0
+    ActiveRecord::Base.connection.schema_cache.clear!
+  end
+
+  teardown do
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+
+    ActiveRecord::Base.connection.initialize_schema_migrations_table
+    ActiveRecord::Base.connection.execute "DELETE FROM #{ActiveRecord::Migrator.schema_migrations_table_name}"
+
+    %w(things awesome_things prefix_things_suffix p_awesome_things_s ).each do |table|
+      Thing.connection.drop_table(table) rescue nil
+    end
+    Thing.reset_column_information
+
+    %w(reminders people_reminders prefix_reminders_suffix).each do |table|
+      Reminder.connection.drop_table(table) rescue nil
+    end
+    Reminder.reset_table_name
+    Reminder.reset_column_information
+
+    %w(last_name key bio age height wealth birthday favorite_day
+       moment_of_truth male administrator funny).each do |column|
+      Person.connection.remove_column('people', column) rescue nil
+    end
+    Person.connection.remove_column("people", "first_name") rescue nil
+    Person.connection.remove_column("people", "middle_name") rescue nil
+    Person.connection.add_column("people", "first_name", :string)
+    Person.reset_column_information
+  end
+
+  def test_migrator_versions
+    migrations_path = MIGRATIONS_ROOT + "/valid"
+    old_path = ActiveRecord::Migrator.migrations_paths
+    ActiveRecord::Migrator.migrations_paths = migrations_path
+
+    ActiveRecord::Migrator.up(migrations_path)
+    assert_equal 3, ActiveRecord::Migrator.current_version
+    assert_equal 3, ActiveRecord::Migrator.last_version
+    assert_equal false, ActiveRecord::Migrator.needs_migration?
+
+    ActiveRecord::Migrator.down(MIGRATIONS_ROOT + "/valid")
+    assert_equal 0, ActiveRecord::Migrator.current_version
+    assert_equal 3, ActiveRecord::Migrator.last_version
+    assert_equal true, ActiveRecord::Migrator.needs_migration?
+  ensure
+    ActiveRecord::Migrator.migrations_paths = old_path
+  end
+
+  def test_migration_version
+    ActiveRecord::Migrator.run(:up, MIGRATIONS_ROOT + "/version_check", 20131219224947)
+  end
+
+  def test_create_table_with_force_true_does_not_drop_nonexisting_table
+    if Person.connection.table_exists?(:testings2)
+      Person.connection.drop_table :testings2
+    end
+
+    # using a copy as we need the drop_table method to
+    # continue to work for the ensure block of the test
+    temp_conn = Person.connection.dup
+
+    assert_not_equal temp_conn, Person.connection
+
+    temp_conn.create_table :testings2, :force => true do |t|
+      t.column :foo, :string
+    end
+  ensure
+    Person.connection.drop_table :testings2 rescue nil
+  end
+
+  def connection
+    ActiveRecord::Base.connection
+  end
+
+  def test_migration_instance_has_connection
+    migration = Class.new(ActiveRecord::Migration).new
+    assert_equal connection, migration.connection
+  end
+
+  def test_method_missing_delegates_to_connection
+    migration = Class.new(ActiveRecord::Migration) {
+      def connection
+        Class.new {
+          def create_table; "hi mom!"; end
+        }.new
+      end
+    }.new
+
+    assert_equal "hi mom!", migration.method_missing(:create_table)
+  end
+
+  def test_add_table_with_decimals
+    Person.connection.drop_table :big_numbers rescue nil
+
+    assert !BigNumber.table_exists?
+    GiveMeBigNumbers.up
+
+    assert BigNumber.create(
+      :bank_balance => 1586.43,
+      :big_bank_balance => BigDecimal("1000234000567.95"),
+      :world_population => 6000000000,
+      :my_house_population => 3,
+      :value_of_e => BigDecimal("2.7182818284590452353602875")
+    )
+
+    b = BigNumber.first
+    assert_not_nil b
+
+    assert_not_nil b.bank_balance
+    assert_not_nil b.big_bank_balance
+    assert_not_nil b.world_population
+    assert_not_nil b.my_house_population
+    assert_not_nil b.value_of_e
+
+    # TODO: set world_population >= 2**62 to cover 64-bit platforms and test
+    # is_a?(Bignum)
+    assert_kind_of Integer, b.world_population
+    assert_equal 6000000000, b.world_population
+    assert_kind_of Fixnum, b.my_house_population
+    assert_equal 3, b.my_house_population
+    assert_kind_of BigDecimal, b.bank_balance
+    assert_equal BigDecimal("1586.43"), b.bank_balance
+    assert_kind_of BigDecimal, b.big_bank_balance
+    assert_equal BigDecimal("1000234000567.95"), b.big_bank_balance
+
+    # This one is fun. The 'value_of_e' field is defined as 'DECIMAL' with
+    # precision/scale explicitly left out.  By the SQL standard, numbers
+    # assigned to this field should be truncated but that's seldom respected.
+    if current_adapter?(:PostgreSQLAdapter)
+      # - PostgreSQL changes the SQL spec on columns declared simply as
+      # "decimal" to something more useful: instead of being given a scale
+      # of 0, they take on the compile-time limit for precision and scale,
+      # so the following should succeed unless you have used really wacky
+      # compilation options
+      # - SQLite2 has the default behavior of preserving all data sent in,
+      # so this happens there too
+      assert_kind_of BigDecimal, b.value_of_e
+      assert_equal BigDecimal("2.7182818284590452353602875"), b.value_of_e
+    elsif current_adapter?(:SQLite3Adapter)
+      # - SQLite3 stores a float, in violation of SQL
+      assert_kind_of BigDecimal, b.value_of_e
+      assert_in_delta BigDecimal("2.71828182845905"), b.value_of_e, 0.00000000000001
+    else
+      # - SQL standard is an integer
+      assert_kind_of Fixnum, b.value_of_e
+      assert_equal 2, b.value_of_e
+    end
+
+    GiveMeBigNumbers.down
+    assert_raise(ActiveRecord::StatementInvalid) { BigNumber.first }
+  end
+
+  def test_filtering_migrations
+    assert_no_column Person, :last_name
+    assert !Reminder.table_exists?
+
+    name_filter = lambda { |migration| migration.name == "ValidPeopleHaveLastNames" }
+    ActiveRecord::Migrator.up(MIGRATIONS_ROOT + "/valid", &name_filter)
+
+    assert_column Person, :last_name
+    assert_raise(ActiveRecord::StatementInvalid) { Reminder.first }
+
+    ActiveRecord::Migrator.down(MIGRATIONS_ROOT + "/valid", &name_filter)
+
+    assert_no_column Person, :last_name
+    assert_raise(ActiveRecord::StatementInvalid) { Reminder.first }
+  end
+
+  class MockMigration < ActiveRecord::Migration
+    attr_reader :went_up, :went_down
+    def initialize
+      @went_up   = false
+      @went_down = false
+    end
+
+    def up
+      @went_up = true
+      super
+    end
+
+    def down
+      @went_down = true
+      super
+    end
+  end
+
+  def test_instance_based_migration_up
+    migration = MockMigration.new
+    assert !migration.went_up, 'have not gone up'
+    assert !migration.went_down, 'have not gone down'
+
+    migration.migrate :up
+    assert migration.went_up, 'have gone up'
+    assert !migration.went_down, 'have not gone down'
+  end
+
+  def test_instance_based_migration_down
+    migration = MockMigration.new
+    assert !migration.went_up, 'have not gone up'
+    assert !migration.went_down, 'have not gone down'
+
+    migration.migrate :down
+    assert !migration.went_up, 'have gone up'
+    assert migration.went_down, 'have not gone down'
+  end
+
+  if ActiveRecord::Base.connection.supports_ddl_transactions?
+    def test_migrator_one_up_with_exception_and_rollback
+      assert_no_column Person, :last_name
+
+      migration = Class.new(ActiveRecord::Migration) {
+        def version; 100 end
+        def migrate(x)
+          add_column "people", "last_name", :string
+          raise 'Something broke'
+        end
+      }.new
+
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 100)
+
+      e = assert_raise(StandardError) { migrator.migrate }
+
+      assert_equal "An error has occurred, this and all later migrations canceled:\n\nSomething broke", e.message
+
+      assert_no_column Person, :last_name,
+        "On error, the Migrator should revert schema changes but it did not."
+    end
+
+    def test_migrator_one_up_with_exception_and_rollback_using_run
+      assert_no_column Person, :last_name
+
+      migration = Class.new(ActiveRecord::Migration) {
+        def version; 100 end
+        def migrate(x)
+          add_column "people", "last_name", :string
+          raise 'Something broke'
+        end
+      }.new
+
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 100)
+
+      e = assert_raise(StandardError) { migrator.run }
+
+      assert_equal "An error has occurred, this migration was canceled:\n\nSomething broke", e.message
+
+      assert_no_column Person, :last_name,
+        "On error, the Migrator should revert schema changes but it did not."
+    end
+
+    def test_migration_without_transaction
+      assert_no_column Person, :last_name
+
+      migration = Class.new(ActiveRecord::Migration) {
+        self.disable_ddl_transaction!
+
+        def version; 101 end
+        def migrate(x)
+          add_column "people", "last_name", :string
+          raise 'Something broke'
+        end
+      }.new
+
+      migrator = ActiveRecord::Migrator.new(:up, [migration], 101)
+      e = assert_raise(StandardError) { migrator.migrate }
+      assert_equal "An error has occurred, all later migrations canceled:\n\nSomething broke", e.message
+
+      assert_column Person, :last_name,
+        "without ddl transactions, the Migrator should not rollback on error but it did."
+    ensure
+      Person.reset_column_information
+      if Person.column_names.include?('last_name')
+        Person.connection.remove_column('people', 'last_name')
+      end
+    end
+  end
+
+  def test_schema_migrations_table_name
+    original_schema_migrations_table_name = ActiveRecord::Migrator.schema_migrations_table_name
+
+    assert_equal "schema_migrations", ActiveRecord::Migrator.schema_migrations_table_name
+    ActiveRecord::Base.table_name_prefix = "prefix_"
+    ActiveRecord::Base.table_name_suffix = "_suffix"
+    Reminder.reset_table_name
+    assert_equal "prefix_schema_migrations_suffix", ActiveRecord::Migrator.schema_migrations_table_name
+    ActiveRecord::Base.schema_migrations_table_name = "changed"
+    Reminder.reset_table_name
+    assert_equal "prefix_changed_suffix", ActiveRecord::Migrator.schema_migrations_table_name
+    ActiveRecord::Base.table_name_prefix = ""
+    ActiveRecord::Base.table_name_suffix = ""
+    Reminder.reset_table_name
+    assert_equal "changed", ActiveRecord::Migrator.schema_migrations_table_name
+  ensure
+    ActiveRecord::Base.schema_migrations_table_name = original_schema_migrations_table_name
+    Reminder.reset_table_name
+  end
+
+  def test_proper_table_name_on_migration
+    reminder_class = new_isolated_reminder_class
+    migration = ActiveRecord::Migration.new
+    assert_equal "table", migration.proper_table_name('table')
+    assert_equal "table", migration.proper_table_name(:table)
+    assert_equal "reminders", migration.proper_table_name(reminder_class)
+    reminder_class.reset_table_name
+    assert_equal reminder_class.table_name, migration.proper_table_name(reminder_class)
+
+    # Use the model's own prefix/suffix if a model is given
+    ActiveRecord::Base.table_name_prefix = "ARprefix_"
+    ActiveRecord::Base.table_name_suffix = "_ARsuffix"
+    reminder_class.table_name_prefix = 'prefix_'
+    reminder_class.table_name_suffix = '_suffix'
+    reminder_class.reset_table_name
+    assert_equal "prefix_reminders_suffix", migration.proper_table_name(reminder_class)
+    reminder_class.table_name_prefix = ''
+    reminder_class.table_name_suffix = ''
+    reminder_class.reset_table_name
+
+    # Use AR::Base's prefix/suffix if string or symbol is given
+    ActiveRecord::Base.table_name_prefix = "prefix_"
+    ActiveRecord::Base.table_name_suffix = "_suffix"
+    reminder_class.reset_table_name
+    assert_equal "prefix_table_suffix", migration.proper_table_name('table', migration.table_name_options)
+    assert_equal "prefix_table_suffix", migration.proper_table_name(:table, migration.table_name_options)
+  end
+
+  def test_rename_table_with_prefix_and_suffix
+    assert !Thing.table_exists?
+    ActiveRecord::Base.table_name_prefix = 'p_'
+    ActiveRecord::Base.table_name_suffix = '_s'
+    Thing.reset_table_name
+    Thing.reset_sequence_name
+    WeNeedThings.up
+
+    assert Thing.create("content" => "hello world")
+    assert_equal "hello world", Thing.first.content
+
+    RenameThings.up
+    Thing.table_name = "p_awesome_things_s"
+
+    assert_equal "hello world", Thing.first.content
+  ensure
+    Thing.reset_table_name
+    Thing.reset_sequence_name
+  end
+
+  def test_add_drop_table_with_prefix_and_suffix
+    assert !Reminder.table_exists?
+    ActiveRecord::Base.table_name_prefix = 'prefix_'
+    ActiveRecord::Base.table_name_suffix = '_suffix'
+    Reminder.reset_table_name
+    Reminder.reset_sequence_name
+    WeNeedReminders.up
+    assert Reminder.create("content" => "hello world", "remind_at" => Time.now)
+    assert_equal "hello world", Reminder.first.content
+
+    WeNeedReminders.down
+    assert_raise(ActiveRecord::StatementInvalid) { Reminder.first }
+  ensure
+    Reminder.reset_sequence_name
+  end
+
+  def test_create_table_with_binary_column
+    Person.connection.drop_table :binary_testings rescue nil
+
+    assert_nothing_raised {
+      Person.connection.create_table :binary_testings do |t|
+        t.column "data", :binary, :null => false
+      end
+    }
+
+    columns = Person.connection.columns(:binary_testings)
+    data_column = columns.detect { |c| c.name == "data" }
+
+    assert_nil data_column.default
+
+    Person.connection.drop_table :binary_testings rescue nil
+  end
+
+  def test_create_table_with_query
+    Person.connection.drop_table :table_from_query_testings rescue nil
+    Person.connection.create_table(:person, force: true)
+
+    Person.connection.create_table :table_from_query_testings, as: "SELECT id FROM person"
+
+    columns = Person.connection.columns(:table_from_query_testings)
+    assert_equal 1, columns.length
+    assert_equal "id", columns.first.name
+
+    Person.connection.drop_table :table_from_query_testings rescue nil
+  end
+
+  def test_create_table_with_query_from_relation
+    Person.connection.drop_table :table_from_query_testings rescue nil
+    Person.connection.create_table(:person, force: true)
+
+    Person.connection.create_table :table_from_query_testings, as: Person.select(:id)
+
+    columns = Person.connection.columns(:table_from_query_testings)
+    assert_equal 1, columns.length
+    assert_equal "id", columns.first.name
+
+    Person.connection.drop_table :table_from_query_testings rescue nil
+  end
+
+  if current_adapter? :OracleAdapter
+    def test_create_table_with_custom_sequence_name
+      # table name is 29 chars, the standard sequence name will
+      # be 33 chars and should be shortened
+      assert_nothing_raised do
+        begin
+          Person.connection.create_table :table_with_name_thats_just_ok do |t|
+            t.column :foo, :string, :null => false
+          end
+        ensure
+          Person.connection.drop_table :table_with_name_thats_just_ok rescue nil
+        end
+      end
+
+      # should be all good w/ a custom sequence name
+      assert_nothing_raised do
+        begin
+          Person.connection.create_table :table_with_name_thats_just_ok,
+            :sequence_name => 'suitably_short_seq' do |t|
+            t.column :foo, :string, :null => false
+          end
+
+          Person.connection.execute("select suitably_short_seq.nextval from dual")
+
+        ensure
+          Person.connection.drop_table :table_with_name_thats_just_ok,
+            :sequence_name => 'suitably_short_seq' rescue nil
+        end
+      end
+
+      # confirm the custom sequence got dropped
+      assert_raise(ActiveRecord::StatementInvalid) do
+        Person.connection.execute("select suitably_short_seq.nextval from dual")
+      end
+    end
+  end
+
+  if current_adapter?(:MysqlAdapter, :Mysql2Adapter, :PostgreSQLAdapter)
+    def test_out_of_range_limit_should_raise
+      Person.connection.drop_table :test_limits rescue nil
+      assert_raise(ActiveRecord::ActiveRecordError, "integer limit didn't raise") do
+        Person.connection.create_table :test_integer_limits, :force => true do |t|
+          t.column :bigone, :integer, :limit => 10
+        end
+      end
+
+      unless current_adapter?(:PostgreSQLAdapter)
+        assert_raise(ActiveRecord::ActiveRecordError, "text limit didn't raise") do
+          Person.connection.create_table :test_text_limits, :force => true do |t|
+            t.column :bigtext, :text, :limit => 0xfffffffff
+          end
+        end
+      end
+
+      Person.connection.drop_table :test_limits rescue nil
+    end
+  end
+
+  protected
+    # This is needed to isolate class_attribute assignments like `table_name_prefix`
+    # for each test case.
+    def new_isolated_reminder_class
+      Class.new(Reminder) {
+        def self.name; "Reminder"; end
+        def self.base_class; self; end
+      }
+    end
+end
+
+class ReservedWordsMigrationTest < ActiveRecord::TestCase
+  def test_drop_index_from_table_named_values
+    connection = Person.connection
+    connection.create_table :values, :force => true do |t|
+      t.integer :value
+    end
+
+    assert_nothing_raised do
+      connection.add_index :values, :value
+      connection.remove_index :values, :column => :value
+    end
+
+    connection.drop_table :values rescue nil
+  end
+end
+
+class ExplicitlyNamedIndexMigrationTest < ActiveRecord::TestCase
+  def test_drop_index_by_name
+    connection = Person.connection
+    connection.create_table :values, force: true do |t|
+      t.integer :value
+    end
+
+    assert_nothing_raised ArgumentError do
+      connection.add_index :values, :value, name: 'a_different_name'
+      connection.remove_index :values, column: :value, name: 'a_different_name'
+    end
+
+    connection.drop_table :values rescue nil
+  end
+end
+
+if ActiveRecord::Base.connection.supports_bulk_alter?
+  class BulkAlterTableMigrationsTest < ActiveRecord::TestCase
+    def setup
+      @connection = Person.connection
+      @connection.create_table(:delete_me, :force => true) {|t| }
+      Person.reset_column_information
+      Person.reset_sequence_name
+    end
+
+    teardown do
+      Person.connection.drop_table(:delete_me) rescue nil
+    end
+
+    def test_adding_multiple_columns
+      assert_queries(1) do
+        with_bulk_change_table do |t|
+          t.column :name, :string
+          t.string :qualification, :experience
+          t.integer :age, :default => 0
+          t.date :birthdate
+          t.timestamps
+        end
+      end
+
+      assert_equal 8, columns.size
+      [:name, :qualification, :experience].each {|s| assert_equal :string, column(s).type }
+      assert_equal '0', column(:age).default
+    end
+
+    def test_removing_columns
+      with_bulk_change_table do |t|
+        t.string :qualification, :experience
+      end
+
+      [:qualification, :experience].each {|c| assert column(c) }
+
+      assert_queries(1) do
+        with_bulk_change_table do |t|
+          t.remove :qualification, :experience
+          t.string :qualification_experience
+        end
+      end
+
+      [:qualification, :experience].each {|c| assert ! column(c) }
+      assert column(:qualification_experience)
+    end
+
+    def test_adding_indexes
+      with_bulk_change_table do |t|
+        t.string :username
+        t.string :name
+        t.integer :age
+      end
+
+      # Adding an index fires a query every time to check if an index already exists or not
+      assert_queries(3) do
+        with_bulk_change_table do |t|
+          t.index :username, :unique => true, :name => :awesome_username_index
+          t.index [:name, :age]
+        end
+      end
+
+      assert_equal 2, indexes.size
+
+      name_age_index = index(:index_delete_me_on_name_and_age)
+      assert_equal ['name', 'age'].sort, name_age_index.columns.sort
+      assert ! name_age_index.unique
+
+      assert index(:awesome_username_index).unique
+    end
+
+    def test_removing_index
+      with_bulk_change_table do |t|
+        t.string :name
+        t.index :name
+      end
+
+      assert index(:index_delete_me_on_name)
+
+      assert_queries(3) do
+        with_bulk_change_table do |t|
+          t.remove_index :name
+          t.index :name, :name => :new_name_index, :unique => true
+        end
+      end
+
+      assert ! index(:index_delete_me_on_name)
+
+      new_name_index = index(:new_name_index)
+      assert new_name_index.unique
+    end
+
+    def test_changing_columns
+      with_bulk_change_table do |t|
+        t.string :name
+        t.date :birthdate
+      end
+
+      assert ! column(:name).default
+      assert_equal :date, column(:birthdate).type
+
+      # One query for columns (delete_me table)
+      # One query for primary key (delete_me table)
+      # One query to do the bulk change
+      assert_queries(3, :ignore_none => true) do
+        with_bulk_change_table do |t|
+          t.change :name, :string, :default => 'NONAME'
+          t.change :birthdate, :datetime
+        end
+      end
+
+      assert_equal 'NONAME', column(:name).default
+      assert_equal :datetime, column(:birthdate).type
+    end
+
+    protected
+
+    def with_bulk_change_table
+      # Reset columns/indexes cache as we're changing the table
+      @columns = @indexes = nil
+
+      Person.connection.change_table(:delete_me, :bulk => true) do |t|
+        yield t
+      end
+    end
+
+    def column(name)
+      columns.detect {|c| c.name == name.to_s }
+    end
+
+    def columns
+      @columns ||= Person.connection.columns('delete_me')
+    end
+
+    def index(name)
+      indexes.detect {|i| i.name == name.to_s }
+    end
+
+    def indexes
+      @indexes ||= Person.connection.indexes('delete_me')
+    end
+  end # AlterTableMigrationsTest
+
+end
+
+class CopyMigrationsTest < ActiveRecord::TestCase
+  def setup
+  end
+
+  def clear
+    ActiveRecord::Base.timestamped_migrations = true
+    to_delete = Dir[@migrations_path + "/*.rb"] - @existing_migrations
+    File.delete(*to_delete)
+  end
+
+  def test_copying_migrations_without_timestamps
+    ActiveRecord::Base.timestamped_migrations = false
+    @migrations_path = MIGRATIONS_ROOT + "/valid"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy"})
+    assert File.exist?(@migrations_path + "/4_people_have_hobbies.bukkits.rb")
+    assert File.exist?(@migrations_path + "/5_people_have_descriptions.bukkits.rb")
+    assert_equal [@migrations_path + "/4_people_have_hobbies.bukkits.rb", @migrations_path + "/5_people_have_descriptions.bukkits.rb"], copied.map(&:filename)
+
+    expected = "# This migration comes from bukkits (originally 1)"
+    assert_equal expected, IO.readlines(@migrations_path + "/4_people_have_hobbies.bukkits.rb")[0].chomp
+
+    files_count = Dir[@migrations_path + "/*.rb"].length
+    copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy"})
+    assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+    assert copied.empty?
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_without_timestamps_from_2_sources
+    ActiveRecord::Base.timestamped_migrations = false
+    @migrations_path = MIGRATIONS_ROOT + "/valid"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    sources = {}
+    sources[:bukkits] = MIGRATIONS_ROOT + "/to_copy"
+    sources[:omg] = MIGRATIONS_ROOT + "/to_copy2"
+    ActiveRecord::Migration.copy(@migrations_path, sources)
+    assert File.exist?(@migrations_path + "/4_people_have_hobbies.bukkits.rb")
+    assert File.exist?(@migrations_path + "/5_people_have_descriptions.bukkits.rb")
+    assert File.exist?(@migrations_path + "/6_create_articles.omg.rb")
+    assert File.exist?(@migrations_path + "/7_create_comments.omg.rb")
+
+    files_count = Dir[@migrations_path + "/*.rb"].length
+    ActiveRecord::Migration.copy(@migrations_path, sources)
+    assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_with_timestamps
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    travel_to(Time.utc(2010, 7, 26, 10, 10, 10)) do
+      copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy_with_timestamps"})
+      assert File.exist?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+      expected = [@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb",
+                  @migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb"]
+      assert_equal expected, copied.map(&:filename)
+
+      files_count = Dir[@migrations_path + "/*.rb"].length
+      copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy_with_timestamps"})
+      assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+      assert copied.empty?
+    end
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_with_timestamps_from_2_sources
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    sources = {}
+    sources[:bukkits] = MIGRATIONS_ROOT + "/to_copy_with_timestamps"
+    sources[:omg]     = MIGRATIONS_ROOT + "/to_copy_with_timestamps2"
+
+    travel_to(Time.utc(2010, 7, 26, 10, 10, 10)) do
+      copied = ActiveRecord::Migration.copy(@migrations_path, sources)
+      assert File.exist?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101012_create_articles.omg.rb")
+      assert File.exist?(@migrations_path + "/20100726101013_create_comments.omg.rb")
+      assert_equal 4, copied.length
+
+      files_count = Dir[@migrations_path + "/*.rb"].length
+      ActiveRecord::Migration.copy(@migrations_path, sources)
+      assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+    end
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_with_timestamps_to_destination_with_timestamps_in_future
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    travel_to(Time.utc(2010, 2, 20, 10, 10, 10)) do
+      ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy_with_timestamps"})
+      assert File.exist?(@migrations_path + "/20100301010102_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100301010103_people_have_descriptions.bukkits.rb")
+
+      files_count = Dir[@migrations_path + "/*.rb"].length
+      copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy_with_timestamps"})
+      assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+      assert copied.empty?
+    end
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_preserving_magic_comments
+    ActiveRecord::Base.timestamped_migrations = false
+    @migrations_path = MIGRATIONS_ROOT + "/valid"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/magic"})
+    assert File.exist?(@migrations_path + "/4_currencies_have_symbols.bukkits.rb")
+    assert_equal [@migrations_path + "/4_currencies_have_symbols.bukkits.rb"], copied.map(&:filename)
+
+    expected = "# coding: ISO-8859-15\n# This migration comes from bukkits (originally 1)"
+    assert_equal expected, IO.readlines(@migrations_path + "/4_currencies_have_symbols.bukkits.rb")[0..1].join.chomp
+
+    files_count = Dir[@migrations_path + "/*.rb"].length
+    copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/magic"})
+    assert_equal files_count, Dir[@migrations_path + "/*.rb"].length
+    assert copied.empty?
+  ensure
+    clear
+  end
+
+  def test_skipping_migrations
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    sources = {}
+    sources[:bukkits] = MIGRATIONS_ROOT + "/to_copy_with_timestamps"
+    sources[:omg]     = MIGRATIONS_ROOT + "/to_copy_with_name_collision"
+
+    skipped = []
+    on_skip = Proc.new { |name, migration| skipped << "#{name} #{migration.name}" }
+    copied = ActiveRecord::Migration.copy(@migrations_path, sources, :on_skip => on_skip)
+    assert_equal 2, copied.length
+
+    assert_equal 1, skipped.length
+    assert_equal ["omg PeopleHaveHobbies"], skipped
+  ensure
+    clear
+  end
+
+  def test_skip_is_not_called_if_migrations_are_from_the_same_plugin
+    @migrations_path = MIGRATIONS_ROOT + "/valid_with_timestamps"
+    @existing_migrations = Dir[@migrations_path + "/*.rb"]
+
+    sources = {}
+    sources[:bukkits] = MIGRATIONS_ROOT + "/to_copy_with_timestamps"
+
+    skipped = []
+    on_skip = Proc.new { |name, migration| skipped << "#{name} #{migration.name}" }
+    copied = ActiveRecord::Migration.copy(@migrations_path, sources, :on_skip => on_skip)
+    ActiveRecord::Migration.copy(@migrations_path, sources, :on_skip => on_skip)
+
+    assert_equal 2, copied.length
+    assert_equal 0, skipped.length
+  ensure
+    clear
+  end
+
+  def test_copying_migrations_to_non_existing_directory
+    @migrations_path = MIGRATIONS_ROOT + "/non_existing"
+    @existing_migrations = []
+
+    travel_to(Time.utc(2010, 7, 26, 10, 10, 10)) do
+      copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy_with_timestamps"})
+      assert File.exist?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+      assert_equal 2, copied.length
+    end
+  ensure
+    clear
+    Dir.delete(@migrations_path)
+  end
+
+  def test_copying_migrations_to_empty_directory
+    @migrations_path = MIGRATIONS_ROOT + "/empty"
+    @existing_migrations = []
+
+    travel_to(Time.utc(2010, 7, 26, 10, 10, 10)) do
+      copied = ActiveRecord::Migration.copy(@migrations_path, {:bukkits => MIGRATIONS_ROOT + "/to_copy_with_timestamps"})
+      assert File.exist?(@migrations_path + "/20100726101010_people_have_hobbies.bukkits.rb")
+      assert File.exist?(@migrations_path + "/20100726101011_people_have_descriptions.bukkits.rb")
+      assert_equal 2, copied.length
+    end
+  ensure
+    clear
+  end
+
+  def test_check_pending_with_stdlib_logger
+    old, ActiveRecord::Base.logger = ActiveRecord::Base.logger, ::Logger.new($stdout)
+    quietly do
+      assert_nothing_raised { ActiveRecord::Migration::CheckPending.new(Proc.new {}).call({}) }
+    end
+  ensure
+    ActiveRecord::Base.logger = old
+  end
+
+  private
+
+  def quietly
+    silence_stream(STDOUT) do
+      silence_stream(STDERR) do
+        yield
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/migrator_test.rb b/activerecord/test/cases/migrator_test.rb
new file mode 100644
index 0000000000..9568aa2217
--- /dev/null
+++ b/activerecord/test/cases/migrator_test.rb
@@ -0,0 +1,377 @@
+require "cases/helper"
+require "cases/migration/helper"
+
+module ActiveRecord
+  class MigratorTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    # Use this class to sense if migrations have gone
+    # up or down.
+    class Sensor < ActiveRecord::Migration
+      attr_reader :went_up, :went_down
+
+      def initialize name = self.class.name, version = nil
+        super
+        @went_up  = false
+        @went_down = false
+      end
+
+      def up; @went_up = true; end
+      def down; @went_down = true; end
+    end
+
+    def setup
+      super
+      ActiveRecord::SchemaMigration.create_table
+      ActiveRecord::SchemaMigration.delete_all rescue nil
+    end
+
+    teardown do
+      ActiveRecord::SchemaMigration.delete_all rescue nil
+      ActiveRecord::Migration.verbose = true
+    end
+
+    def test_migrator_with_duplicate_names
+      assert_raises(ActiveRecord::DuplicateMigrationNameError, "Multiple migrations have the name Chunky") do
+        list = [Migration.new('Chunky'), Migration.new('Chunky')]
+        ActiveRecord::Migrator.new(:up, list)
+      end
+    end
+
+    def test_migrator_with_duplicate_versions
+      assert_raises(ActiveRecord::DuplicateMigrationVersionError) do
+        list = [Migration.new('Foo', 1), Migration.new('Bar', 1)]
+        ActiveRecord::Migrator.new(:up, list)
+      end
+    end
+
+    def test_migrator_with_missing_version_numbers
+      assert_raises(ActiveRecord::UnknownMigrationVersionError) do
+        list = [Migration.new('Foo', 1), Migration.new('Bar', 2)]
+        ActiveRecord::Migrator.new(:up, list, 3).run
+      end
+    end
+
+    def test_finds_migrations
+      migrations = ActiveRecord::Migrator.migrations(MIGRATIONS_ROOT + "/valid")
+
+      [[1, 'ValidPeopleHaveLastNames'], [2, 'WeNeedReminders'], [3, 'InnocentJointable']].each_with_index do |pair, i|
+        assert_equal migrations[i].version, pair.first
+        assert_equal migrations[i].name, pair.last
+      end
+    end
+
+    def test_finds_migrations_in_subdirectories
+      migrations = ActiveRecord::Migrator.migrations(MIGRATIONS_ROOT + "/valid_with_subdirectories")
+
+      [[1, 'ValidPeopleHaveLastNames'], [2, 'WeNeedReminders'], [3, 'InnocentJointable']].each_with_index do |pair, i|
+        assert_equal migrations[i].version, pair.first
+        assert_equal migrations[i].name, pair.last
+      end
+    end
+
+    def test_finds_migrations_from_two_directories
+      directories = [MIGRATIONS_ROOT + '/valid_with_timestamps', MIGRATIONS_ROOT + '/to_copy_with_timestamps']
+      migrations = ActiveRecord::Migrator.migrations directories
+
+      [[20090101010101, "PeopleHaveHobbies"],
+       [20090101010202, "PeopleHaveDescriptions"],
+       [20100101010101, "ValidWithTimestampsPeopleHaveLastNames"],
+       [20100201010101, "ValidWithTimestampsWeNeedReminders"],
+       [20100301010101, "ValidWithTimestampsInnocentJointable"]].each_with_index do |pair, i|
+        assert_equal pair.first, migrations[i].version
+        assert_equal pair.last, migrations[i].name
+       end
+    end
+
+    def test_finds_migrations_in_numbered_directory
+      migrations = ActiveRecord::Migrator.migrations [MIGRATIONS_ROOT + '/10_urban']
+      assert_equal 9, migrations[0].version
+      assert_equal 'AddExpressions', migrations[0].name
+    end
+
+    def test_relative_migrations
+      list = Dir.chdir(MIGRATIONS_ROOT) do
+        ActiveRecord::Migrator.migrations("valid")
+      end
+
+      migration_proxy = list.find { |item|
+        item.name == 'ValidPeopleHaveLastNames'
+      }
+      assert migration_proxy, 'should find pending migration'
+    end
+
+    def test_finds_pending_migrations
+      ActiveRecord::SchemaMigration.create!(:version => '1')
+      migration_list = [ Migration.new('foo', 1), Migration.new('bar', 3) ]
+      migrations = ActiveRecord::Migrator.new(:up, migration_list).pending_migrations
+
+      assert_equal 1, migrations.size
+      assert_equal migration_list.last, migrations.first
+    end
+
+    def test_migrator_interleaved_migrations
+      pass_one = [Sensor.new('One', 1)]
+
+      ActiveRecord::Migrator.new(:up, pass_one).migrate
+      assert pass_one.first.went_up
+      assert_not pass_one.first.went_down
+
+      pass_two = [Sensor.new('One', 1), Sensor.new('Three', 3)]
+      ActiveRecord::Migrator.new(:up, pass_two).migrate
+      assert_not pass_two[0].went_up
+      assert pass_two[1].went_up
+      assert pass_two.all? { |x| !x.went_down }
+
+      pass_three = [Sensor.new('One', 1),
+                    Sensor.new('Two', 2),
+                    Sensor.new('Three', 3)]
+
+      ActiveRecord::Migrator.new(:down, pass_three).migrate
+      assert pass_three[0].went_down
+      assert_not pass_three[1].went_down
+      assert pass_three[2].went_down
+    end
+
+    def test_up_calls_up
+      migrations = [Sensor.new(nil, 0), Sensor.new(nil, 1), Sensor.new(nil, 2)]
+      ActiveRecord::Migrator.new(:up, migrations).migrate
+      assert migrations.all? { |m| m.went_up }
+      assert migrations.all? { |m| !m.went_down }
+      assert_equal 2, ActiveRecord::Migrator.current_version
+    end
+
+    def test_down_calls_down
+      test_up_calls_up
+
+      migrations = [Sensor.new(nil, 0), Sensor.new(nil, 1), Sensor.new(nil, 2)]
+      ActiveRecord::Migrator.new(:down, migrations).migrate
+      assert migrations.all? { |m| !m.went_up }
+      assert migrations.all? { |m| m.went_down }
+      assert_equal 0, ActiveRecord::Migrator.current_version
+    end
+
+    def test_current_version
+      ActiveRecord::SchemaMigration.create!(:version => '1000')
+      assert_equal 1000, ActiveRecord::Migrator.current_version
+    end
+
+    def test_migrator_one_up
+      calls, migrations = sensors(3)
+
+      ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+      assert_equal [[:up, 1]], calls
+      calls.clear
+
+      ActiveRecord::Migrator.new(:up, migrations, 2).migrate
+      assert_equal [[:up, 2]], calls
+    end
+
+    def test_migrator_one_down
+      calls, migrations = sensors(3)
+
+      ActiveRecord::Migrator.new(:up, migrations).migrate
+      assert_equal [[:up, 1], [:up, 2], [:up, 3]], calls
+      calls.clear
+
+      ActiveRecord::Migrator.new(:down, migrations, 1).migrate
+
+      assert_equal [[:down, 3], [:down, 2]], calls
+    end
+
+    def test_migrator_one_up_one_down
+      calls, migrations = sensors(3)
+
+      ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+      assert_equal [[:up, 1]], calls
+      calls.clear
+
+      ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+      assert_equal [[:down, 1]], calls
+    end
+
+    def test_migrator_double_up
+      calls, migrations = sensors(3)
+      assert_equal(0, ActiveRecord::Migrator.current_version)
+
+      ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+      assert_equal [[:up, 1]], calls
+      calls.clear
+
+      ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+      assert_equal [], calls
+    end
+
+    def test_migrator_double_down
+      calls, migrations = sensors(3)
+
+      assert_equal(0, ActiveRecord::Migrator.current_version)
+
+      ActiveRecord::Migrator.new(:up, migrations, 1).run
+      assert_equal [[:up, 1]], calls
+      calls.clear
+
+      ActiveRecord::Migrator.new(:down, migrations, 1).run
+      assert_equal [[:down, 1]], calls
+      calls.clear
+
+      ActiveRecord::Migrator.new(:down, migrations, 1).run
+      assert_equal [], calls
+
+      assert_equal(0, ActiveRecord::Migrator.current_version)
+    end
+
+    def test_migrator_verbosity
+      _, migrations = sensors(3)
+
+      ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+      assert_not_equal 0, ActiveRecord::Migration.message_count
+
+      ActiveRecord::Migration.message_count = 0
+
+      ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+      assert_not_equal 0, ActiveRecord::Migration.message_count
+      ActiveRecord::Migration.message_count = 0
+    end
+
+    def test_migrator_verbosity_off
+      _, migrations = sensors(3)
+
+      ActiveRecord::Migration.message_count = 0
+      ActiveRecord::Migration.verbose = false
+      ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+      assert_equal 0, ActiveRecord::Migration.message_count
+      ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+      assert_equal 0, ActiveRecord::Migration.message_count
+    end
+
+    def test_target_version_zero_should_run_only_once
+      calls, migrations = sensors(3)
+
+      # migrate up to 1
+      ActiveRecord::Migrator.new(:up, migrations, 1).migrate
+      assert_equal [[:up, 1]], calls
+      calls.clear
+
+      # migrate down to 0
+      ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+      assert_equal [[:down, 1]], calls
+      calls.clear
+
+      # migrate down to 0 again
+      ActiveRecord::Migrator.new(:down, migrations, 0).migrate
+      assert_equal [], calls
+    end
+
+    def test_migrator_going_down_due_to_version_target
+      calls, migrator = migrator_class(3)
+
+      migrator.up("valid", 1)
+      assert_equal [[:up, 1]], calls
+      calls.clear
+
+      migrator.migrate("valid", 0)
+      assert_equal [[:down, 1]], calls
+      calls.clear
+
+      migrator.migrate("valid")
+      assert_equal [[:up, 1], [:up, 2], [:up, 3]], calls
+    end
+
+    def test_migrator_rollback
+      _, migrator = migrator_class(3)
+
+      migrator.migrate("valid")
+      assert_equal(3, ActiveRecord::Migrator.current_version)
+
+      migrator.rollback("valid")
+      assert_equal(2, ActiveRecord::Migrator.current_version)
+
+      migrator.rollback("valid")
+      assert_equal(1, ActiveRecord::Migrator.current_version)
+
+      migrator.rollback("valid")
+      assert_equal(0, ActiveRecord::Migrator.current_version)
+
+      migrator.rollback("valid")
+      assert_equal(0, ActiveRecord::Migrator.current_version)
+    end
+
+    def test_migrator_db_has_no_schema_migrations_table
+      _, migrator = migrator_class(3)
+
+      ActiveRecord::Base.connection.execute("DROP TABLE schema_migrations")
+      assert_not ActiveRecord::Base.connection.table_exists?('schema_migrations')
+      migrator.migrate("valid", 1)
+      assert ActiveRecord::Base.connection.table_exists?('schema_migrations')
+    end
+
+    def test_migrator_forward
+      _, migrator = migrator_class(3)
+      migrator.migrate("/valid", 1)
+      assert_equal(1, ActiveRecord::Migrator.current_version)
+
+      migrator.forward("/valid", 2)
+      assert_equal(3, ActiveRecord::Migrator.current_version)
+
+      migrator.forward("/valid")
+      assert_equal(3, ActiveRecord::Migrator.current_version)
+    end
+
+    def test_only_loads_pending_migrations
+      # migrate up to 1
+      ActiveRecord::SchemaMigration.create!(:version => '1')
+
+      calls, migrator = migrator_class(3)
+      migrator.migrate("valid", nil)
+
+      assert_equal [[:up, 2], [:up, 3]], calls
+    end
+
+    def test_get_all_versions
+      _, migrator = migrator_class(3)
+
+      migrator.migrate("valid")
+      assert_equal([1,2,3], ActiveRecord::Migrator.get_all_versions)
+
+      migrator.rollback("valid")
+      assert_equal([1,2], ActiveRecord::Migrator.get_all_versions)
+
+      migrator.rollback("valid")
+      assert_equal([1], ActiveRecord::Migrator.get_all_versions)
+
+      migrator.rollback("valid")
+      assert_equal([], ActiveRecord::Migrator.get_all_versions)
+    end
+
+    private
+    def m(name, version, &block)
+      x = Sensor.new name, version
+      x.extend(Module.new {
+        define_method(:up) { block.call(:up, x); super() }
+        define_method(:down) { block.call(:down, x); super() }
+      }) if block_given?
+    end
+
+    def sensors(count)
+      calls = []
+      migrations = count.times.map { |i|
+        m(nil, i + 1) { |c,migration|
+          calls << [c, migration.version]
+        }
+      }
+      [calls, migrations]
+    end
+
+    def migrator_class(count)
+      calls, migrations = sensors(count)
+
+      migrator = Class.new(Migrator).extend(Module.new {
+        define_method(:migrations) { |paths|
+          migrations
+        }
+      })
+      [calls, migrator]
+    end
+  end
+end
diff --git a/activerecord/test/cases/mixin_test.rb b/activerecord/test/cases/mixin_test.rb
new file mode 100644
index 0000000000..7ddb2bfee1
--- /dev/null
+++ b/activerecord/test/cases/mixin_test.rb
@@ -0,0 +1,70 @@
+require "cases/helper"
+
+class Mixin < ActiveRecord::Base
+end
+
+class TouchTest < ActiveRecord::TestCase
+  fixtures :mixins
+
+  setup do
+    travel_to Time.now
+  end
+
+  teardown do
+    travel_back
+  end
+
+  def test_update
+    stamped = Mixin.new
+
+    assert_nil stamped.updated_at
+    assert_nil stamped.created_at
+    stamped.save
+    assert_equal Time.now, stamped.updated_at
+    assert_equal Time.now, stamped.created_at
+  end
+
+  def test_create
+    obj = Mixin.create
+    assert_equal Time.now, obj.updated_at
+    assert_equal Time.now, obj.created_at
+  end
+
+  def test_many_updates
+    stamped = Mixin.new
+
+    assert_nil stamped.updated_at
+    assert_nil stamped.created_at
+    stamped.save
+    assert_equal Time.now, stamped.created_at
+    assert_equal Time.now, stamped.updated_at
+
+    old_updated_at = stamped.updated_at
+
+    travel 5.minutes do
+      stamped.lft_will_change!
+      stamped.save
+
+      assert_equal Time.now, stamped.updated_at
+      assert_equal old_updated_at, stamped.created_at
+    end
+  end
+
+  def test_create_turned_off
+    Mixin.record_timestamps = false
+
+    mixin = Mixin.new
+
+    assert_nil mixin.updated_at
+    mixin.save
+    assert_nil mixin.updated_at
+
+  # Make sure Mixin.record_timestamps gets reset, even if this test fails,
+  # so that other tests do not fail because Mixin.record_timestamps == false
+  rescue Exception => e
+    raise e
+  ensure
+    Mixin.record_timestamps = true
+  end
+
+end
diff --git a/activerecord/test/cases/modules_test.rb b/activerecord/test/cases/modules_test.rb
new file mode 100644
index 0000000000..e87773df94
--- /dev/null
+++ b/activerecord/test/cases/modules_test.rb
@@ -0,0 +1,172 @@
+require "cases/helper"
+require 'models/company_in_module'
+require 'models/shop'
+require 'models/developer'
+
+class ModulesTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :projects, :developers, :collections, :products, :variants
+
+  def setup
+    # need to make sure Object::Firm and Object::Client are not defined,
+    # so that constantize will not be able to cheat when having to load namespaced classes
+    @undefined_consts = {}
+
+    [:Firm, :Client].each do |const|
+      @undefined_consts.merge! const => Object.send(:remove_const, const) if Object.const_defined?(const)
+    end
+
+    ActiveRecord::Base.store_full_sti_class = false
+  end
+
+  teardown do
+    # reinstate the constants that we undefined in the setup
+    @undefined_consts.each do |constant, value|
+      Object.send :const_set, constant, value unless value.nil?
+    end
+
+    ActiveRecord::Base.store_full_sti_class = true
+  end
+
+  def test_module_spanning_associations
+    firm = MyApplication::Business::Firm.first
+    assert !firm.clients.empty?, "Firm should have clients"
+    assert_nil firm.class.table_name.match('::'), "Firm shouldn't have the module appear in its table name"
+  end
+
+  def test_module_spanning_has_and_belongs_to_many_associations
+    project = MyApplication::Business::Project.first
+    project.developers << MyApplication::Business::Developer.create("name" => "John")
+    assert_equal "John", project.developers.last.name
+  end
+
+  def test_associations_spanning_cross_modules
+    account = MyApplication::Billing::Account.all.merge!(:order => 'id').first
+    assert_kind_of MyApplication::Business::Firm, account.firm
+    assert_kind_of MyApplication::Billing::Firm, account.qualified_billing_firm
+    assert_kind_of MyApplication::Billing::Firm, account.unqualified_billing_firm
+    assert_kind_of MyApplication::Billing::Nested::Firm, account.nested_qualified_billing_firm
+    assert_kind_of MyApplication::Billing::Nested::Firm, account.nested_unqualified_billing_firm
+  end
+
+  def test_find_account_and_include_company
+    account = MyApplication::Billing::Account.all.merge!(:includes => :firm).find(1)
+    assert_kind_of MyApplication::Business::Firm, account.firm
+  end
+
+  def test_table_name
+    assert_equal 'accounts', MyApplication::Billing::Account.table_name, 'table_name for ActiveRecord model in module'
+    assert_equal 'companies', MyApplication::Business::Client.table_name, 'table_name for ActiveRecord model subclass'
+    assert_equal 'company_contacts', MyApplication::Business::Client::Contact.table_name, 'table_name for ActiveRecord model enclosed by another ActiveRecord model'
+  end
+
+  def test_assign_ids
+    firm = MyApplication::Business::Firm.first
+
+    assert_nothing_raised NameError, "Should be able to resolve all class constants via reflection" do
+      firm.client_ids = [MyApplication::Business::Client.first.id]
+    end
+  end
+
+  # need to add an eager loading condition to force the eager loading model into
+  # the old join model, to test that. See http://dev.rubyonrails.org/ticket/9640
+  def test_eager_loading_in_modules
+    clients = []
+
+    assert_nothing_raised NameError, "Should be able to resolve all class constants via reflection" do
+      clients << MyApplication::Business::Client.references(:accounts).merge!(:includes => {:firm => :account}, :where => 'accounts.id IS NOT NULL').find(3)
+      clients << MyApplication::Business::Client.includes(:firm => :account).find(3)
+    end
+
+    clients.each do |client|
+      assert_no_queries do
+        assert_not_nil(client.firm.account)
+      end
+    end
+  end
+
+  def test_module_table_name_prefix
+    assert_equal 'prefixed_companies', MyApplication::Business::Prefixed::Company.table_name, 'inferred table_name for ActiveRecord model in module with table_name_prefix'
+    assert_equal 'prefixed_companies', MyApplication::Business::Prefixed::Nested::Company.table_name, 'table_name for ActiveRecord model in nested module with a parent table_name_prefix'
+    assert_equal 'companies', MyApplication::Business::Prefixed::Firm.table_name, 'explicit table_name for ActiveRecord model in module with table_name_prefix should not be prefixed'
+  end
+
+  def test_module_table_name_prefix_with_global_prefix
+    classes = [ MyApplication::Business::Company,
+                MyApplication::Business::Firm,
+                MyApplication::Business::Client,
+                MyApplication::Business::Client::Contact,
+                MyApplication::Business::Developer,
+                MyApplication::Business::Project,
+                MyApplication::Business::Prefixed::Company,
+                MyApplication::Business::Prefixed::Nested::Company,
+                MyApplication::Billing::Account ]
+
+    ActiveRecord::Base.table_name_prefix = 'global_'
+    classes.each(&:reset_table_name)
+    assert_equal 'global_companies', MyApplication::Business::Company.table_name, 'inferred table_name for ActiveRecord model in module without table_name_prefix'
+    assert_equal 'prefixed_companies', MyApplication::Business::Prefixed::Company.table_name, 'inferred table_name for ActiveRecord model in module with table_name_prefix'
+    assert_equal 'prefixed_companies', MyApplication::Business::Prefixed::Nested::Company.table_name, 'table_name for ActiveRecord model in nested module with a parent table_name_prefix'
+    assert_equal 'companies', MyApplication::Business::Prefixed::Firm.table_name, 'explicit table_name for ActiveRecord model in module with table_name_prefix should not be prefixed'
+  ensure
+    ActiveRecord::Base.table_name_prefix = ''
+    classes.each(&:reset_table_name)
+  end
+
+  def test_module_table_name_suffix
+    assert_equal 'companies_suffixed', MyApplication::Business::Suffixed::Company.table_name, 'inferred table_name for ActiveRecord model in module with table_name_suffix'
+    assert_equal 'companies_suffixed', MyApplication::Business::Suffixed::Nested::Company.table_name, 'table_name for ActiveRecord model in nested module with a parent table_name_suffix'
+    assert_equal 'companies', MyApplication::Business::Suffixed::Firm.table_name, 'explicit table_name for ActiveRecord model in module with table_name_suffix should not be suffixed'
+  end
+
+  def test_module_table_name_suffix_with_global_suffix
+    classes = [ MyApplication::Business::Company,
+                MyApplication::Business::Firm,
+                MyApplication::Business::Client,
+                MyApplication::Business::Client::Contact,
+                MyApplication::Business::Developer,
+                MyApplication::Business::Project,
+                MyApplication::Business::Suffixed::Company,
+                MyApplication::Business::Suffixed::Nested::Company,
+                MyApplication::Billing::Account ]
+
+    ActiveRecord::Base.table_name_suffix = '_global'
+    classes.each(&:reset_table_name)
+    assert_equal 'companies_global', MyApplication::Business::Company.table_name, 'inferred table_name for ActiveRecord model in module without table_name_suffix'
+    assert_equal 'companies_suffixed', MyApplication::Business::Suffixed::Company.table_name, 'inferred table_name for ActiveRecord model in module with table_name_suffix'
+    assert_equal 'companies_suffixed', MyApplication::Business::Suffixed::Nested::Company.table_name, 'table_name for ActiveRecord model in nested module with a parent table_name_suffix'
+    assert_equal 'companies', MyApplication::Business::Suffixed::Firm.table_name, 'explicit table_name for ActiveRecord model in module with table_name_suffix should not be suffixed'
+  ensure
+    ActiveRecord::Base.table_name_suffix = ''
+    classes.each(&:reset_table_name)
+  end
+
+  def test_compute_type_can_infer_class_name_of_sibling_inside_module
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+    assert_equal MyApplication::Business::Firm, MyApplication::Business::Client.send(:compute_type, "Firm")
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_nested_models_should_not_raise_exception_when_using_delete_all_dependency_on_association
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+
+    collection = Shop::Collection.first
+    assert !collection.products.empty?, "Collection should have products"
+    assert_nothing_raised { collection.destroy }
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+
+  def test_nested_models_should_not_raise_exception_when_using_nullify_dependency_on_association
+    old = ActiveRecord::Base.store_full_sti_class
+    ActiveRecord::Base.store_full_sti_class = true
+
+    product = Shop::Product.first
+    assert !product.variants.empty?, "Product should have variants"
+    assert_nothing_raised { product.destroy }
+  ensure
+    ActiveRecord::Base.store_full_sti_class = old
+  end
+end
diff --git a/activerecord/test/cases/multiparameter_attributes_test.rb b/activerecord/test/cases/multiparameter_attributes_test.rb
new file mode 100644
index 0000000000..14d4ef457d
--- /dev/null
+++ b/activerecord/test/cases/multiparameter_attributes_test.rb
@@ -0,0 +1,350 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/customer'
+
+class MultiParameterAttributeTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  def test_multiparameter_attributes_on_date
+    attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "6", "last_read(3i)" => "24" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # note that extra #to_date call allows test to pass for Oracle, which
+    # treats dates/times the same
+    assert_date_from_db Date.new(2004, 6, 24), topic.last_read.to_date
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_year
+    attributes = { "last_read(1i)" => "", "last_read(2i)" => "6", "last_read(3i)" => "24" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # note that extra #to_date call allows test to pass for Oracle, which
+    # treats dates/times the same
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_month
+    attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "", "last_read(3i)" => "24" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # note that extra #to_date call allows test to pass for Oracle, which
+    # treats dates/times the same
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_day
+    attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "6", "last_read(3i)" => "" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # note that extra #to_date call allows test to pass for Oracle, which
+    # treats dates/times the same
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_day_and_year
+    attributes = { "last_read(1i)" => "", "last_read(2i)" => "6", "last_read(3i)" => "" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # note that extra #to_date call allows test to pass for Oracle, which
+    # treats dates/times the same
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_day_and_month
+    attributes = { "last_read(1i)" => "2004", "last_read(2i)" => "", "last_read(3i)" => "" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # note that extra #to_date call allows test to pass for Oracle, which
+    # treats dates/times the same
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_empty_year_and_month
+    attributes = { "last_read(1i)" => "", "last_read(2i)" => "", "last_read(3i)" => "24" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # note that extra #to_date call allows test to pass for Oracle, which
+    # treats dates/times the same
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_date_with_all_empty
+    attributes = { "last_read(1i)" => "", "last_read(2i)" => "", "last_read(3i)" => "" }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.last_read
+  end
+
+  def test_multiparameter_attributes_on_time
+    with_timezone_config default: :local do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2004, 6, 24, 16, 24, 0), topic.written_on
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_no_date
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      attributes = {
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+    end
+    assert_equal("written_on", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_attributes_on_time_with_invalid_time_params
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "2004", "written_on(5i)" => "36", "written_on(6i)" => "64",
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+    end
+    assert_equal("written_on", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_attributes_on_time_with_old_date
+    attributes = {
+      "written_on(1i)" => "1850", "written_on(2i)" => "6", "written_on(3i)" => "24",
+      "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    # testing against to_s(:db) representation because either a Time or a DateTime might be returned, depending on platform
+    assert_equal "1850-06-24 16:24:00", topic.written_on.to_s(:db)
+  end
+
+  def test_multiparameter_attributes_on_time_will_raise_on_big_time_if_missing_date_parts
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      attributes = {
+        "written_on(4i)" => "16", "written_on(5i)" => "24"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+    end
+    assert_equal("written_on", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_attributes_on_time_with_raise_on_small_time_if_missing_date_parts
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      attributes = {
+        "written_on(4i)" => "16", "written_on(5i)" => "12", "written_on(6i)" => "02"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+    end
+    assert_equal("written_on", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_attributes_on_time_will_ignore_hour_if_missing
+    with_timezone_config default: :local do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "12", "written_on(3i)" => "12",
+        "written_on(5i)" => "12", "written_on(6i)" => "02"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2004, 12, 12, 0, 12, 2), topic.written_on
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_will_ignore_hour_if_blank
+    attributes = {
+      "written_on(1i)" => "", "written_on(2i)" => "", "written_on(3i)" => "",
+      "written_on(4i)" => "", "written_on(5i)" => "12", "written_on(6i)" => "02"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.written_on
+  end
+
+  def test_multiparameter_attributes_on_time_will_ignore_date_if_empty
+    attributes = {
+      "written_on(1i)" => "", "written_on(2i)" => "", "written_on(3i)" => "",
+      "written_on(4i)" => "16", "written_on(5i)" => "24"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.written_on
+  end
+
+  def test_multiparameter_attributes_on_time_with_seconds_will_ignore_date_if_empty
+    attributes = {
+      "written_on(1i)" => "", "written_on(2i)" => "", "written_on(3i)" => "",
+      "written_on(4i)" => "16", "written_on(5i)" => "12", "written_on(6i)" => "02"
+    }
+    topic = Topic.find(1)
+    topic.attributes = attributes
+    assert_nil topic.written_on
+  end
+
+  def test_multiparameter_attributes_on_time_with_utc
+    with_timezone_config default: :utc do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.utc(2004, 6, 24, 16, 24, 0), topic.written_on
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_time_zone_aware_attributes
+    with_timezone_config default: :utc, aware_attributes: true, zone: -28800 do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.utc(2004, 6, 24, 23, 24, 0), topic.written_on
+      assert_equal Time.utc(2004, 6, 24, 16, 24, 0), topic.written_on.time
+      assert_equal Time.zone, topic.written_on.time_zone
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_time_zone_aware_attributes_false
+    with_timezone_config default: :local, aware_attributes: false, zone: -28800 do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2004, 6, 24, 16, 24, 0), topic.written_on
+      assert_equal false, topic.written_on.respond_to?(:time_zone)
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_skip_time_zone_conversion_for_attributes
+    with_timezone_config default: :utc, aware_attributes: true, zone: -28800 do
+      Topic.skip_time_zone_conversion_for_attributes = [:written_on]
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00"
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.utc(2004, 6, 24, 16, 24, 0), topic.written_on
+      assert_equal false, topic.written_on.respond_to?(:time_zone)
+    end
+  ensure
+    Topic.skip_time_zone_conversion_for_attributes = []
+  end
+
+  # Oracle does not have a TIME datatype.
+  unless current_adapter?(:OracleAdapter)
+    def test_multiparameter_attributes_on_time_only_column_with_time_zone_aware_attributes_does_not_do_time_zone_conversion
+      with_timezone_config default: :utc, aware_attributes: true, zone: -28800 do
+        attributes = {
+          "bonus_time(1i)" => "2000", "bonus_time(2i)" => "1", "bonus_time(3i)" => "1",
+          "bonus_time(4i)" => "16", "bonus_time(5i)" => "24"
+        }
+        topic = Topic.find(1)
+        topic.attributes = attributes
+        assert_equal Time.utc(2000, 1, 1, 16, 24, 0), topic.bonus_time
+        assert topic.bonus_time.utc?
+      end
+    end
+  end
+
+  def test_multiparameter_attributes_on_time_with_empty_seconds
+    with_timezone_config default: :local do
+      attributes = {
+        "written_on(1i)" => "2004", "written_on(2i)" => "6", "written_on(3i)" => "24",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => ""
+      }
+      topic = Topic.find(1)
+      topic.attributes = attributes
+      assert_equal Time.local(2004, 6, 24, 16, 24, 0), topic.written_on
+    end
+  end
+
+  unless current_adapter? :OracleAdapter
+    def test_multiparameter_attributes_setting_time_attribute
+      topic = Topic.new( "bonus_time(4i)"=> "01", "bonus_time(5i)" => "05" )
+      assert_equal 1, topic.bonus_time.hour
+      assert_equal 5, topic.bonus_time.min
+    end
+  end
+
+  def test_multiparameter_attributes_setting_date_attribute
+    topic = Topic.new( "written_on(1i)" => "1952", "written_on(2i)" => "3", "written_on(3i)" => "11" )
+    assert_equal 1952, topic.written_on.year
+    assert_equal 3, topic.written_on.month
+    assert_equal 11, topic.written_on.day
+  end
+
+  def test_multiparameter_attributes_setting_date_and_time_attribute
+    topic = Topic.new(
+        "written_on(1i)" => "1952",
+        "written_on(2i)" => "3",
+        "written_on(3i)" => "11",
+        "written_on(4i)" => "13",
+        "written_on(5i)" => "55")
+    assert_equal 1952, topic.written_on.year
+    assert_equal 3, topic.written_on.month
+    assert_equal 11, topic.written_on.day
+    assert_equal 13, topic.written_on.hour
+    assert_equal 55, topic.written_on.min
+  end
+
+  def test_multiparameter_attributes_setting_time_but_not_date_on_date_field
+    assert_raise( ActiveRecord::MultiparameterAssignmentErrors ) do
+      Topic.new( "written_on(4i)" => "13", "written_on(5i)" => "55" )
+    end
+  end
+
+  def test_multiparameter_assignment_of_aggregation
+    customer = Customer.new
+    address = Address.new("The Street", "The City", "The Country")
+    attributes = { "address(1)" => address.street, "address(2)" => address.city, "address(3)" => address.country }
+    customer.attributes = attributes
+    assert_equal address, customer.address
+  end
+
+  def test_multiparameter_assignment_of_aggregation_out_of_order
+    customer = Customer.new
+    address = Address.new("The Street", "The City", "The Country")
+    attributes = { "address(3)" => address.country, "address(2)" => address.city, "address(1)" => address.street }
+    customer.attributes = attributes
+    assert_equal address, customer.address
+  end
+
+  def test_multiparameter_assignment_of_aggregation_with_missing_values
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      customer = Customer.new
+      address = Address.new("The Street", "The City", "The Country")
+      attributes = { "address(2)" => address.city, "address(3)" => address.country }
+      customer.attributes = attributes
+    end
+    assert_equal("address", ex.errors[0].attribute)
+  end
+
+  def test_multiparameter_assignment_of_aggregation_with_blank_values
+    customer = Customer.new
+    address = Address.new("The Street", "The City", "The Country")
+    attributes = { "address(1)" => "", "address(2)" => address.city, "address(3)" => address.country }
+    customer.attributes = attributes
+    assert_equal Address.new(nil, "The City", "The Country"), customer.address
+  end
+
+  def test_multiparameter_assignment_of_aggregation_with_large_index
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      customer = Customer.new
+      address = Address.new("The Street", "The City", "The Country")
+      attributes = { "address(1)" => "The Street", "address(2)" => address.city, "address(3000)" => address.country }
+      customer.attributes = attributes
+    end
+
+    assert_equal("address", ex.errors[0].attribute)
+  end
+end
diff --git a/activerecord/test/cases/multiple_db_test.rb b/activerecord/test/cases/multiple_db_test.rb
new file mode 100644
index 0000000000..3831de6ae3
--- /dev/null
+++ b/activerecord/test/cases/multiple_db_test.rb
@@ -0,0 +1,108 @@
+require "cases/helper"
+require 'models/entrant'
+require 'models/bird'
+require 'models/course'
+
+class MultipleDbTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  def setup
+    @courses  = create_fixtures("courses") { Course.retrieve_connection }
+    @colleges = create_fixtures("colleges") { College.retrieve_connection }
+    @entrants = create_fixtures("entrants")
+  end
+
+  def test_connected
+    assert_not_nil Entrant.connection
+    assert_not_nil Course.connection
+  end
+
+  def test_proper_connection
+    assert_not_equal(Entrant.connection, Course.connection)
+    assert_equal(Entrant.connection, Entrant.retrieve_connection)
+    assert_equal(Course.connection, Course.retrieve_connection)
+    assert_equal(ActiveRecord::Base.connection, Entrant.connection)
+  end
+
+  def test_find
+    c1 = Course.find(1)
+    assert_equal "Ruby Development", c1.name
+    c2 = Course.find(2)
+    assert_equal "Java Development", c2.name
+    e1 = Entrant.find(1)
+    assert_equal "Ruby Developer", e1.name
+    e2 = Entrant.find(2)
+    assert_equal "Ruby Guru", e2.name
+    e3 = Entrant.find(3)
+    assert_equal "Java Lover", e3.name
+  end
+
+  def test_associations
+    c1 = Course.find(1)
+    assert_equal 2, c1.entrants.count
+    e1 = Entrant.find(1)
+    assert_equal e1.course.id, c1.id
+    c2 = Course.find(2)
+    assert_equal 1, c2.entrants.count
+    e3 = Entrant.find(3)
+    assert_equal e3.course.id, c2.id
+  end
+
+  def test_course_connection_should_survive_dependency_reload
+    assert Course.connection
+
+    ActiveSupport::Dependencies.clear
+    Object.send(:remove_const, :Course)
+    require_dependency 'models/course'
+
+    assert Course.connection
+  end
+
+  def test_transactions_across_databases
+    c1 = Course.find(1)
+    e1 = Entrant.find(1)
+
+    begin
+      Course.transaction do
+        Entrant.transaction do
+          c1.name = "Typo"
+          e1.name = "Typo"
+          c1.save
+          e1.save
+          raise "No I messed up."
+        end
+      end
+    rescue
+      # Yup caught it
+    end
+
+    assert_equal "Typo", c1.name
+    assert_equal "Typo", e1.name
+
+    assert_equal "Ruby Development", Course.find(1).name
+    assert_equal "Ruby Developer", Entrant.find(1).name
+  end
+
+  def test_arel_table_engines
+    assert_not_equal Entrant.arel_engine, Bird.arel_engine
+    assert_not_equal Entrant.arel_engine, Course.arel_engine
+  end
+
+  def test_connection
+    assert_equal Entrant.arel_engine.connection, Bird.arel_engine.connection
+    assert_not_equal Entrant.arel_engine.connection, Course.arel_engine.connection
+  end
+
+  unless in_memory_db?
+    def test_associations_should_work_when_model_has_no_connection
+      begin
+        ActiveRecord::Base.remove_connection
+        assert_nothing_raised ActiveRecord::ConnectionNotEstablished do
+          College.first.courses.first
+        end
+      ensure
+        ActiveRecord::Base.establish_connection :arunit
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/nested_attributes_test.rb b/activerecord/test/cases/nested_attributes_test.rb
new file mode 100644
index 0000000000..cf96c3fccf
--- /dev/null
+++ b/activerecord/test/cases/nested_attributes_test.rb
@@ -0,0 +1,1040 @@
+require "cases/helper"
+require "models/pirate"
+require "models/ship"
+require "models/ship_part"
+require "models/bird"
+require "models/parrot"
+require "models/treasure"
+require "models/man"
+require "models/interest"
+require "models/owner"
+require "models/pet"
+require 'active_support/hash_with_indifferent_access'
+
+class TestNestedAttributesInGeneral < ActiveRecord::TestCase
+  teardown do
+    Pirate.accepts_nested_attributes_for :ship, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? }
+  end
+
+  def test_base_should_have_an_empty_nested_attributes_options
+    assert_equal Hash.new, ActiveRecord::Base.nested_attributes_options
+  end
+
+  def test_should_add_a_proc_to_nested_attributes_options
+    assert_equal ActiveRecord::NestedAttributes::ClassMethods::REJECT_ALL_BLANK_PROC,
+                 Pirate.nested_attributes_options[:birds_with_reject_all_blank][:reject_if]
+
+    [:parrots, :birds].each do |name|
+      assert_instance_of Proc, Pirate.nested_attributes_options[name][:reject_if]
+    end
+  end
+
+  def test_should_not_build_a_new_record_using_reject_all_even_if_destroy_is_given
+    pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    pirate.birds_with_reject_all_blank_attributes = [{:name => '', :color => '', :_destroy => '0'}]
+    pirate.save!
+
+    assert pirate.birds_with_reject_all_blank.empty?
+  end
+
+  def test_should_not_build_a_new_record_if_reject_all_blank_returns_false
+    pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    pirate.birds_with_reject_all_blank_attributes = [{:name => '', :color => ''}]
+    pirate.save!
+
+    assert pirate.birds_with_reject_all_blank.empty?
+  end
+
+  def test_should_build_a_new_record_if_reject_all_blank_does_not_return_false
+    pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    pirate.birds_with_reject_all_blank_attributes = [{:name => 'Tweetie', :color => ''}]
+    pirate.save!
+
+    assert_equal 1, pirate.birds_with_reject_all_blank.count
+    assert_equal 'Tweetie', pirate.birds_with_reject_all_blank.first.name
+  end
+
+  def test_should_raise_an_ArgumentError_for_non_existing_associations
+    exception = assert_raise ArgumentError do
+      Pirate.accepts_nested_attributes_for :honesty
+    end
+    assert_equal "No association found for name `honesty'. Has it been defined yet?", exception.message
+  end
+
+  def test_should_disable_allow_destroy_by_default
+    Pirate.accepts_nested_attributes_for :ship
+
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    ship = pirate.create_ship(name: 'Nights Dirty Lightning')
+
+    pirate.update(ship_attributes: { '_destroy' => true, :id => ship.id })
+
+    assert_nothing_raised(ActiveRecord::RecordNotFound) { pirate.ship.reload }
+  end
+
+  def test_a_model_should_respond_to_underscore_destroy_and_return_if_it_is_marked_for_destruction
+    ship = Ship.create!(:name => 'Nights Dirty Lightning')
+    assert !ship._destroy
+    ship.mark_for_destruction
+    assert ship._destroy
+  end
+
+  def test_reject_if_method_without_arguments
+    Pirate.accepts_nested_attributes_for :ship, :reject_if => :new_record?
+
+    pirate = Pirate.new(:catchphrase => "Stop wastin' me time")
+    pirate.ship_attributes = { :name => 'Black Pearl' }
+    assert_no_difference('Ship.count') { pirate.save! }
+  end
+
+  def test_reject_if_method_with_arguments
+    Pirate.accepts_nested_attributes_for :ship, :reject_if => :reject_empty_ships_on_create
+
+    pirate = Pirate.new(:catchphrase => "Stop wastin' me time")
+    pirate.ship_attributes = { :name => 'Red Pearl', :_reject_me_if_new => true }
+    assert_no_difference('Ship.count') { pirate.save! }
+
+    # pirate.reject_empty_ships_on_create returns false for saved pirate records
+    # in the previous step note that pirate gets saved but ship fails
+    pirate.ship_attributes = { :name => 'Red Pearl', :_reject_me_if_new => true }
+    assert_difference('Ship.count') { pirate.save! }
+  end
+
+  def test_reject_if_with_indifferent_keys
+    Pirate.accepts_nested_attributes_for :ship, :reject_if => proc {|attributes| attributes[:name].blank? }
+
+    pirate = Pirate.new(:catchphrase => "Stop wastin' me time")
+    pirate.ship_attributes = { :name => 'Hello Pearl' }
+    assert_difference('Ship.count') { pirate.save! }
+  end
+
+  def test_reject_if_with_a_proc_which_returns_true_always_for_has_one
+    Pirate.accepts_nested_attributes_for :ship, :reject_if => proc {|attributes| true }
+    pirate = Pirate.new(catchphrase: "Stop wastin' me time")
+    ship = pirate.create_ship(name: 's1')
+    pirate.update({ship_attributes: { name: 's2', id: ship.id } })
+    assert_equal 's1', ship.reload.name
+  end
+
+  def test_reuse_already_built_new_record
+    pirate = Pirate.new
+    ship_built_first = pirate.build_ship
+    pirate.ship_attributes = { name: 'Ship 1' }
+    assert_equal ship_built_first.object_id, pirate.ship.object_id
+  end
+
+  def test_do_not_allow_assigning_foreign_key_when_reusing_existing_new_record
+    pirate = Pirate.create!(catchphrase: "Don' botharrr talkin' like one, savvy?")
+    pirate.build_ship
+    pirate.ship_attributes = { name: 'Ship 1', pirate_id: pirate.id + 1 }
+    assert_equal pirate.id, pirate.ship.pirate_id
+  end
+
+  def test_reject_if_with_a_proc_which_returns_true_always_for_has_many
+    Man.accepts_nested_attributes_for :interests, :reject_if => proc {|attributes| true }
+    man = Man.create(name: "John")
+    interest = man.interests.create(topic: 'photography')
+    man.update({interests_attributes: { topic: 'gardening', id: interest.id } })
+    assert_equal 'photography', interest.reload.topic
+  end
+
+  def test_destroy_works_independent_of_reject_if
+    Man.accepts_nested_attributes_for :interests, :reject_if => proc {|attributes| true }, :allow_destroy => true
+    man = Man.create(name: "Jon")
+    interest = man.interests.create(topic: 'the ladies')
+    man.update({interests_attributes: { _destroy: "1", id: interest.id } })
+    assert man.reload.interests.empty?
+  end
+
+  def test_has_many_association_updating_a_single_record
+    Man.accepts_nested_attributes_for(:interests)
+    man = Man.create(name: 'John')
+    interest = man.interests.create(topic: 'photography')
+    man.update({interests_attributes: {topic: 'gardening', id: interest.id}})
+    assert_equal 'gardening', interest.reload.topic
+  end
+
+  def test_reject_if_with_blank_nested_attributes_id
+    # When using a select list to choose an existing 'ship' id, with include_blank: true
+    Pirate.accepts_nested_attributes_for :ship, :reject_if => proc {|attributes| attributes[:id].blank? }
+
+    pirate = Pirate.new(:catchphrase => "Stop wastin' me time")
+    pirate.ship_attributes = { :id => "" }
+    assert_nothing_raised(ActiveRecord::RecordNotFound) { pirate.save! }
+  end
+
+  def test_first_and_array_index_zero_methods_return_the_same_value_when_nested_attributes_are_set_to_update_existing_record
+    Man.accepts_nested_attributes_for(:interests)
+    man = Man.create(:name => "John")
+    interest = man.interests.create :topic => 'gardening'
+    man = Man.find man.id
+    man.interests_attributes = [{:id => interest.id, :topic => 'gardening'}]
+    assert_equal man.interests.first.topic, man.interests[0].topic
+  end
+
+  def test_allows_class_to_override_setter_and_call_super
+    mean_pirate_class = Class.new(Pirate) do
+      accepts_nested_attributes_for :parrot
+      def parrot_attributes=(attrs)
+        super(attrs.merge(:color => "blue"))
+      end
+    end
+    mean_pirate = mean_pirate_class.new
+    mean_pirate.parrot_attributes = { :name => "James" }
+    assert_equal "James", mean_pirate.parrot.name
+    assert_equal "blue", mean_pirate.parrot.color
+  end
+
+  def test_accepts_nested_attributes_for_can_be_overridden_in_subclasses
+    Pirate.accepts_nested_attributes_for(:parrot)
+
+    mean_pirate_class = Class.new(Pirate) do
+      accepts_nested_attributes_for :parrot
+    end
+    mean_pirate = mean_pirate_class.new
+    mean_pirate.parrot_attributes = { :name => "James" }
+    assert_equal "James", mean_pirate.parrot.name
+  end
+end
+
+class TestNestedAttributesOnAHasOneAssociation < ActiveRecord::TestCase
+  def setup
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @ship = @pirate.create_ship(:name => 'Nights Dirty Lightning')
+  end
+
+  def test_should_raise_argument_error_if_trying_to_build_polymorphic_belongs_to
+    exception = assert_raise ArgumentError do
+      Treasure.new(:name => 'pearl', :looter_attributes => {:catchphrase => "Arrr"})
+    end
+    assert_equal "Cannot build association `looter'. Are you trying to build a polymorphic one-to-one association?", exception.message
+  end
+
+  def test_should_define_an_attribute_writer_method_for_the_association
+    assert_respond_to @pirate, :ship_attributes=
+  end
+
+  def test_should_build_a_new_record_if_there_is_no_id
+    @ship.destroy
+    @pirate.reload.ship_attributes = { :name => 'Davy Jones Gold Dagger' }
+
+    assert !@pirate.ship.persisted?
+    assert_equal 'Davy Jones Gold Dagger', @pirate.ship.name
+  end
+
+  def test_should_not_build_a_new_record_if_there_is_no_id_and_destroy_is_truthy
+    @ship.destroy
+    @pirate.reload.ship_attributes = { :name => 'Davy Jones Gold Dagger', :_destroy => '1' }
+
+    assert_nil @pirate.ship
+  end
+
+  def test_should_not_build_a_new_record_if_a_reject_if_proc_returns_false
+    @ship.destroy
+    @pirate.reload.ship_attributes = {}
+
+    assert_nil @pirate.ship
+  end
+
+  def test_should_replace_an_existing_record_if_there_is_no_id
+    @pirate.reload.ship_attributes = { :name => 'Davy Jones Gold Dagger' }
+
+    assert !@pirate.ship.persisted?
+    assert_equal 'Davy Jones Gold Dagger', @pirate.ship.name
+    assert_equal 'Nights Dirty Lightning', @ship.name
+  end
+
+  def test_should_not_replace_an_existing_record_if_there_is_no_id_and_destroy_is_truthy
+    @pirate.reload.ship_attributes = { :name => 'Davy Jones Gold Dagger', :_destroy => '1' }
+
+    assert_equal @ship, @pirate.ship
+    assert_equal 'Nights Dirty Lightning', @pirate.ship.name
+  end
+
+  def test_should_modify_an_existing_record_if_there_is_a_matching_id
+    @pirate.reload.ship_attributes = { :id => @ship.id, :name => 'Davy Jones Gold Dagger' }
+
+    assert_equal @ship, @pirate.ship
+    assert_equal 'Davy Jones Gold Dagger', @pirate.ship.name
+  end
+
+  def test_should_raise_RecordNotFound_if_an_id_is_given_but_doesnt_return_a_record
+    exception = assert_raise ActiveRecord::RecordNotFound do
+      @pirate.ship_attributes = { :id => 1234567890 }
+    end
+    assert_equal "Couldn't find Ship with ID=1234567890 for Pirate with ID=#{@pirate.id}", exception.message
+  end
+
+  def test_should_take_a_hash_with_string_keys_and_update_the_associated_model
+    @pirate.reload.ship_attributes = { 'id' => @ship.id, 'name' => 'Davy Jones Gold Dagger' }
+
+    assert_equal @ship, @pirate.ship
+    assert_equal 'Davy Jones Gold Dagger', @pirate.ship.name
+  end
+
+  def test_should_modify_an_existing_record_if_there_is_a_matching_composite_id
+    @ship.stubs(:id).returns('ABC1X')
+    @pirate.ship_attributes = { :id => @ship.id, :name => 'Davy Jones Gold Dagger' }
+
+    assert_equal 'Davy Jones Gold Dagger', @pirate.ship.name
+  end
+
+  def test_should_destroy_an_existing_record_if_there_is_a_matching_id_and_destroy_is_truthy
+    @pirate.ship.destroy
+
+    [1, '1', true, 'true'].each do |truth|
+      ship = @pirate.reload.create_ship(name: 'Mister Pablo')
+      @pirate.update(ship_attributes: { id: ship.id, _destroy: truth })
+
+      assert_nil @pirate.reload.ship
+      assert_raise(ActiveRecord::RecordNotFound) { Ship.find(ship.id) }
+    end
+  end
+
+  def test_should_not_destroy_an_existing_record_if_destroy_is_not_truthy
+    [nil, '0', 0, 'false', false].each do |not_truth|
+      @pirate.update(ship_attributes: { id: @pirate.ship.id, _destroy: not_truth })
+
+      assert_equal @ship, @pirate.reload.ship
+    end
+  end
+
+  def test_should_not_destroy_an_existing_record_if_allow_destroy_is_false
+    Pirate.accepts_nested_attributes_for :ship, :allow_destroy => false, :reject_if => proc { |attributes| attributes.empty? }
+
+    @pirate.update(ship_attributes: { id: @pirate.ship.id, _destroy: '1' })
+
+    assert_equal @ship, @pirate.reload.ship
+
+    Pirate.accepts_nested_attributes_for :ship, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? }
+  end
+
+  def test_should_also_work_with_a_HashWithIndifferentAccess
+    @pirate.ship_attributes = ActiveSupport::HashWithIndifferentAccess.new(:id => @ship.id, :name => 'Davy Jones Gold Dagger')
+
+    assert @pirate.ship.persisted?
+    assert_equal 'Davy Jones Gold Dagger', @pirate.ship.name
+  end
+
+  def test_should_work_with_update_as_well
+    @pirate.update({ catchphrase: 'Arr', ship_attributes: { id: @ship.id, name: 'Mister Pablo' } })
+    @pirate.reload
+
+    assert_equal 'Arr', @pirate.catchphrase
+    assert_equal 'Mister Pablo', @pirate.ship.name
+  end
+
+  def test_should_not_destroy_the_associated_model_until_the_parent_is_saved
+    @pirate.attributes = { :ship_attributes => { :id => @ship.id, :_destroy => '1' } }
+
+    assert !@pirate.ship.destroyed?
+    assert @pirate.ship.marked_for_destruction?
+
+    @pirate.save
+
+    assert @pirate.ship.destroyed?
+    assert_nil @pirate.reload.ship
+  end
+
+  def test_should_automatically_enable_autosave_on_the_association
+    assert Pirate.reflect_on_association(:ship).options[:autosave]
+  end
+
+  def test_should_accept_update_only_option
+    @pirate.update(update_only_ship_attributes: { id: @pirate.ship.id, name: 'Mayflower' })
+  end
+
+  def test_should_create_new_model_when_nothing_is_there_and_update_only_is_true
+    @ship.delete
+
+    @pirate.reload.update(update_only_ship_attributes: { name: 'Mayflower' })
+
+    assert_not_nil @pirate.ship
+  end
+
+  def test_should_update_existing_when_update_only_is_true_and_no_id_is_given
+    @ship.delete
+    @ship = @pirate.create_update_only_ship(name: 'Nights Dirty Lightning')
+
+    @pirate.update(update_only_ship_attributes: { name: 'Mayflower' })
+
+    assert_equal 'Mayflower', @ship.reload.name
+    assert_equal @ship, @pirate.reload.ship
+  end
+
+  def test_should_update_existing_when_update_only_is_true_and_id_is_given
+    @ship.delete
+    @ship = @pirate.create_update_only_ship(name: 'Nights Dirty Lightning')
+
+    @pirate.update(update_only_ship_attributes: { name: 'Mayflower', id: @ship.id })
+
+    assert_equal 'Mayflower', @ship.reload.name
+    assert_equal @ship, @pirate.reload.ship
+  end
+
+  def test_should_destroy_existing_when_update_only_is_true_and_id_is_given_and_is_marked_for_destruction
+    Pirate.accepts_nested_attributes_for :update_only_ship, :update_only => true, :allow_destroy => true
+    @ship.delete
+    @ship = @pirate.create_update_only_ship(name: 'Nights Dirty Lightning')
+
+    @pirate.update(update_only_ship_attributes: { name: 'Mayflower', id: @ship.id, _destroy: true })
+
+    assert_nil @pirate.reload.ship
+    assert_raise(ActiveRecord::RecordNotFound) { Ship.find(@ship.id) }
+
+    Pirate.accepts_nested_attributes_for :update_only_ship, :update_only => true, :allow_destroy => false
+  end
+
+end
+
+class TestNestedAttributesOnABelongsToAssociation < ActiveRecord::TestCase
+  def setup
+    @ship = Ship.new(:name => 'Nights Dirty Lightning')
+    @pirate = @ship.build_pirate(:catchphrase => 'Aye')
+    @ship.save!
+  end
+
+  def test_should_define_an_attribute_writer_method_for_the_association
+    assert_respond_to @ship, :pirate_attributes=
+  end
+
+  def test_should_build_a_new_record_if_there_is_no_id
+    @pirate.destroy
+    @ship.reload.pirate_attributes = { :catchphrase => 'Arr' }
+
+    assert !@ship.pirate.persisted?
+    assert_equal 'Arr', @ship.pirate.catchphrase
+  end
+
+  def test_should_not_build_a_new_record_if_there_is_no_id_and_destroy_is_truthy
+    @pirate.destroy
+    @ship.reload.pirate_attributes = { :catchphrase => 'Arr', :_destroy => '1' }
+
+    assert_nil @ship.pirate
+  end
+
+  def test_should_not_build_a_new_record_if_a_reject_if_proc_returns_false
+    @pirate.destroy
+    @ship.reload.pirate_attributes = {}
+
+    assert_nil @ship.pirate
+  end
+
+  def test_should_replace_an_existing_record_if_there_is_no_id
+    @ship.reload.pirate_attributes = { :catchphrase => 'Arr' }
+
+    assert !@ship.pirate.persisted?
+    assert_equal 'Arr', @ship.pirate.catchphrase
+    assert_equal 'Aye', @pirate.catchphrase
+  end
+
+  def test_should_not_replace_an_existing_record_if_there_is_no_id_and_destroy_is_truthy
+    @ship.reload.pirate_attributes = { :catchphrase => 'Arr', :_destroy => '1' }
+
+    assert_equal @pirate, @ship.pirate
+    assert_equal 'Aye', @ship.pirate.catchphrase
+  end
+
+  def test_should_modify_an_existing_record_if_there_is_a_matching_id
+    @ship.reload.pirate_attributes = { :id => @pirate.id, :catchphrase => 'Arr' }
+
+    assert_equal @pirate, @ship.pirate
+    assert_equal 'Arr', @ship.pirate.catchphrase
+  end
+
+  def test_should_raise_RecordNotFound_if_an_id_is_given_but_doesnt_return_a_record
+    exception = assert_raise ActiveRecord::RecordNotFound do
+      @ship.pirate_attributes = { :id => 1234567890 }
+    end
+    assert_equal "Couldn't find Pirate with ID=1234567890 for Ship with ID=#{@ship.id}", exception.message
+  end
+
+  def test_should_take_a_hash_with_string_keys_and_update_the_associated_model
+    @ship.reload.pirate_attributes = { 'id' => @pirate.id, 'catchphrase' => 'Arr' }
+
+    assert_equal @pirate, @ship.pirate
+    assert_equal 'Arr', @ship.pirate.catchphrase
+  end
+
+  def test_should_modify_an_existing_record_if_there_is_a_matching_composite_id
+    @pirate.stubs(:id).returns('ABC1X')
+    @ship.pirate_attributes = { :id => @pirate.id, :catchphrase => 'Arr' }
+
+    assert_equal 'Arr', @ship.pirate.catchphrase
+  end
+
+  def test_should_destroy_an_existing_record_if_there_is_a_matching_id_and_destroy_is_truthy
+    @ship.pirate.destroy
+    [1, '1', true, 'true'].each do |truth|
+      pirate = @ship.reload.create_pirate(catchphrase: 'Arr')
+      @ship.update(pirate_attributes: { id: pirate.id, _destroy: truth })
+      assert_raise(ActiveRecord::RecordNotFound) { pirate.reload }
+    end
+  end
+
+  def test_should_unset_association_when_an_existing_record_is_destroyed
+    original_pirate_id = @ship.pirate.id
+    @ship.update! pirate_attributes: { id: @ship.pirate.id, _destroy: true }
+
+    assert_empty Pirate.where(id: original_pirate_id)
+    assert_nil @ship.pirate_id
+    assert_nil @ship.pirate
+
+    @ship.reload
+    assert_empty Pirate.where(id: original_pirate_id)
+    assert_nil @ship.pirate_id
+    assert_nil @ship.pirate
+  end
+
+  def test_should_not_destroy_an_existing_record_if_destroy_is_not_truthy
+    [nil, '0', 0, 'false', false].each do |not_truth|
+      @ship.update(pirate_attributes: { id: @ship.pirate.id, _destroy: not_truth })
+      assert_nothing_raised(ActiveRecord::RecordNotFound) { @ship.pirate.reload }
+    end
+  end
+
+  def test_should_not_destroy_an_existing_record_if_allow_destroy_is_false
+    Ship.accepts_nested_attributes_for :pirate, :allow_destroy => false, :reject_if => proc { |attributes| attributes.empty? }
+
+    @ship.update(pirate_attributes: { id: @ship.pirate.id, _destroy: '1' })
+    assert_nothing_raised(ActiveRecord::RecordNotFound) { @ship.pirate.reload }
+  ensure
+    Ship.accepts_nested_attributes_for :pirate, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? }
+  end
+
+  def test_should_work_with_update_as_well
+    @ship.update({ name: 'Mister Pablo', pirate_attributes: { catchphrase: 'Arr' } })
+    @ship.reload
+
+    assert_equal 'Mister Pablo', @ship.name
+    assert_equal 'Arr', @ship.pirate.catchphrase
+  end
+
+  def test_should_not_destroy_the_associated_model_until_the_parent_is_saved
+    pirate = @ship.pirate
+
+    @ship.attributes = { :pirate_attributes => { :id => pirate.id, '_destroy' => true } }
+    assert_nothing_raised(ActiveRecord::RecordNotFound) { Pirate.find(pirate.id) }
+    @ship.save
+    assert_raise(ActiveRecord::RecordNotFound) { Pirate.find(pirate.id) }
+  end
+
+  def test_should_automatically_enable_autosave_on_the_association
+    assert Ship.reflect_on_association(:pirate).options[:autosave]
+  end
+
+  def test_should_create_new_model_when_nothing_is_there_and_update_only_is_true
+    @pirate.delete
+    @ship.reload.attributes = { :update_only_pirate_attributes => { :catchphrase => 'Arr' } }
+
+    assert !@ship.update_only_pirate.persisted?
+  end
+
+  def test_should_update_existing_when_update_only_is_true_and_no_id_is_given
+    @pirate.delete
+    @pirate = @ship.create_update_only_pirate(catchphrase: 'Aye')
+
+    @ship.update(update_only_pirate_attributes: { catchphrase: 'Arr' })
+    assert_equal 'Arr', @pirate.reload.catchphrase
+    assert_equal @pirate, @ship.reload.update_only_pirate
+  end
+
+  def test_should_update_existing_when_update_only_is_true_and_id_is_given
+    @pirate.delete
+    @pirate = @ship.create_update_only_pirate(catchphrase: 'Aye')
+
+    @ship.update(update_only_pirate_attributes: { catchphrase: 'Arr', id: @pirate.id })
+
+    assert_equal 'Arr', @pirate.reload.catchphrase
+    assert_equal @pirate, @ship.reload.update_only_pirate
+  end
+
+  def test_should_destroy_existing_when_update_only_is_true_and_id_is_given_and_is_marked_for_destruction
+    Ship.accepts_nested_attributes_for :update_only_pirate, :update_only => true, :allow_destroy => true
+    @pirate.delete
+    @pirate = @ship.create_update_only_pirate(catchphrase: 'Aye')
+
+    @ship.update(update_only_pirate_attributes: { catchphrase: 'Arr', id: @pirate.id, _destroy: true })
+
+    assert_raise(ActiveRecord::RecordNotFound) { @pirate.reload }
+
+    Ship.accepts_nested_attributes_for :update_only_pirate, :update_only => true, :allow_destroy => false
+  end
+end
+
+module NestedAttributesOnACollectionAssociationTests
+  def test_should_define_an_attribute_writer_method_for_the_association
+    assert_respond_to @pirate, association_setter
+  end
+
+  def test_should_save_only_one_association_on_create
+    pirate = Pirate.create!({
+      :catchphrase => 'Arr',
+      association_getter => { 'foo' => { :name => 'Grace OMalley' } }
+    })
+
+    assert_equal 1, pirate.reload.send(@association_name).count
+  end
+
+  def test_should_take_a_hash_with_string_keys_and_assign_the_attributes_to_the_associated_models
+    @alternate_params[association_getter].stringify_keys!
+    @pirate.update @alternate_params
+    assert_equal ['Grace OMalley', 'Privateers Greed'], [@child_1.reload.name, @child_2.reload.name]
+  end
+
+  def test_should_take_an_array_and_assign_the_attributes_to_the_associated_models
+    @pirate.send(association_setter, @alternate_params[association_getter].values)
+    @pirate.save
+    assert_equal ['Grace OMalley', 'Privateers Greed'], [@child_1.reload.name, @child_2.reload.name]
+  end
+
+  def test_should_also_work_with_a_HashWithIndifferentAccess
+    @pirate.send(association_setter, ActiveSupport::HashWithIndifferentAccess.new('foo' => ActiveSupport::HashWithIndifferentAccess.new(:id => @child_1.id, :name => 'Grace OMalley')))
+    @pirate.save
+    assert_equal 'Grace OMalley', @child_1.reload.name
+  end
+
+  def test_should_take_a_hash_and_assign_the_attributes_to_the_associated_models
+    @pirate.attributes = @alternate_params
+    assert_equal 'Grace OMalley', @pirate.send(@association_name).first.name
+    assert_equal 'Privateers Greed', @pirate.send(@association_name).last.name
+  end
+
+  def test_should_not_load_association_when_updating_existing_records
+    @pirate.reload
+    @pirate.send(association_setter, [{ :id => @child_1.id, :name => 'Grace OMalley' }])
+    assert ! @pirate.send(@association_name).loaded?
+
+    @pirate.save
+    assert ! @pirate.send(@association_name).loaded?
+    assert_equal 'Grace OMalley', @child_1.reload.name
+  end
+
+  def test_should_not_overwrite_unsaved_updates_when_loading_association
+    @pirate.reload
+    @pirate.send(association_setter, [{ :id => @child_1.id, :name => 'Grace OMalley' }])
+    assert_equal 'Grace OMalley', @pirate.send(@association_name).send(:load_target).find { |r| r.id == @child_1.id }.name
+  end
+
+  def test_should_preserve_order_when_not_overwriting_unsaved_updates
+    @pirate.reload
+    @pirate.send(association_setter, [{ :id => @child_1.id, :name => 'Grace OMalley' }])
+    assert_equal @child_1.id, @pirate.send(@association_name).send(:load_target).first.id
+  end
+
+  def test_should_refresh_saved_records_when_not_overwriting_unsaved_updates
+    @pirate.reload
+    record = @pirate.class.reflect_on_association(@association_name).klass.new(name: 'Grace OMalley')
+    @pirate.send(@association_name) << record
+    record.save!
+    @pirate.send(@association_name).last.update!(name: 'Polly')
+    assert_equal 'Polly', @pirate.send(@association_name).send(:load_target).last.name
+  end
+
+  def test_should_not_remove_scheduled_destroys_when_loading_association
+    @pirate.reload
+    @pirate.send(association_setter, [{ :id => @child_1.id, :_destroy => '1' }])
+    assert @pirate.send(@association_name).send(:load_target).find { |r| r.id == @child_1.id }.marked_for_destruction?
+  end
+
+  def test_should_take_a_hash_with_composite_id_keys_and_assign_the_attributes_to_the_associated_models
+    @child_1.stubs(:id).returns('ABC1X')
+    @child_2.stubs(:id).returns('ABC2X')
+
+    @pirate.attributes = {
+      association_getter => [
+        { :id => @child_1.id, :name => 'Grace OMalley' },
+        { :id => @child_2.id, :name => 'Privateers Greed' }
+      ]
+    }
+
+    assert_equal ['Grace OMalley', 'Privateers Greed'], [@child_1.name, @child_2.name]
+  end
+
+  def test_should_raise_RecordNotFound_if_an_id_is_given_but_doesnt_return_a_record
+    exception = assert_raise ActiveRecord::RecordNotFound do
+      @pirate.attributes = { association_getter => [{ :id => 1234567890 }] }
+    end
+    assert_equal "Couldn't find #{@child_1.class.name} with ID=1234567890 for Pirate with ID=#{@pirate.id}", exception.message
+  end
+
+  def test_should_automatically_build_new_associated_models_for_each_entry_in_a_hash_where_the_id_is_missing
+    @pirate.send(@association_name).destroy_all
+    @pirate.reload.attributes = {
+      association_getter => { 'foo' => { :name => 'Grace OMalley' }, 'bar' => { :name => 'Privateers Greed' }}
+    }
+
+    assert !@pirate.send(@association_name).first.persisted?
+    assert_equal 'Grace OMalley', @pirate.send(@association_name).first.name
+
+    assert !@pirate.send(@association_name).last.persisted?
+    assert_equal 'Privateers Greed', @pirate.send(@association_name).last.name
+  end
+
+  def test_should_not_assign_destroy_key_to_a_record
+    assert_nothing_raised ActiveRecord::UnknownAttributeError do
+      @pirate.send(association_setter, { 'foo' => { '_destroy' => '0' }})
+    end
+  end
+
+  def test_should_ignore_new_associated_records_with_truthy_destroy_attribute
+    @pirate.send(@association_name).destroy_all
+    @pirate.reload.attributes = {
+      association_getter => {
+        'foo' => { :name => 'Grace OMalley' },
+        'bar' => { :name => 'Privateers Greed', '_destroy' => '1' }
+      }
+    }
+
+    assert_equal 1, @pirate.send(@association_name).length
+    assert_equal 'Grace OMalley', @pirate.send(@association_name).first.name
+  end
+
+  def test_should_ignore_new_associated_records_if_a_reject_if_proc_returns_false
+    @alternate_params[association_getter]['baz'] = {}
+    assert_no_difference("@pirate.send(@association_name).count") do
+      @pirate.attributes = @alternate_params
+    end
+  end
+
+  def test_should_sort_the_hash_by_the_keys_before_building_new_associated_models
+    attributes = {}
+    attributes['123726353'] = { :name => 'Grace OMalley' }
+    attributes['2'] = { :name => 'Privateers Greed' } # 2 is lower then 123726353
+    @pirate.send(association_setter, attributes)
+
+    assert_equal ['Posideons Killer', 'Killer bandita Dionne', 'Privateers Greed', 'Grace OMalley'].to_set, @pirate.send(@association_name).map(&:name).to_set
+  end
+
+  def test_should_raise_an_argument_error_if_something_else_than_a_hash_is_passed
+    assert_nothing_raised(ArgumentError) { @pirate.send(association_setter, {}) }
+    assert_nothing_raised(ArgumentError) { @pirate.send(association_setter, Hash.new) }
+
+    exception = assert_raise ArgumentError do
+      @pirate.send(association_setter, "foo")
+    end
+    assert_equal 'Hash or Array expected, got String ("foo")', exception.message
+  end
+
+  def test_should_work_with_update_as_well
+    @pirate.update(catchphrase: 'Arr',
+      association_getter => { 'foo' => { :id => @child_1.id, :name => 'Grace OMalley' }})
+
+    assert_equal 'Grace OMalley', @child_1.reload.name
+  end
+
+  def test_should_update_existing_records_and_add_new_ones_that_have_no_id
+    @alternate_params[association_getter]['baz'] = { name: 'Buccaneers Servant' }
+    assert_difference('@pirate.send(@association_name).count', +1) do
+      @pirate.update @alternate_params
+    end
+    assert_equal ['Grace OMalley', 'Privateers Greed', 'Buccaneers Servant'].to_set, @pirate.reload.send(@association_name).map(&:name).to_set
+  end
+
+  def test_should_be_possible_to_destroy_a_record
+    ['1', 1, 'true', true].each do |true_variable|
+      record = @pirate.reload.send(@association_name).create!(:name => 'Grace OMalley')
+      @pirate.send(association_setter,
+        @alternate_params[association_getter].merge('baz' => { :id => record.id, '_destroy' => true_variable })
+      )
+
+      assert_difference('@pirate.send(@association_name).count', -1) do
+        @pirate.save
+      end
+    end
+  end
+
+  def test_should_not_destroy_the_associated_model_with_a_non_truthy_argument
+    [nil, '', '0', 0, 'false', false].each do |false_variable|
+      @alternate_params[association_getter]['foo']['_destroy'] = false_variable
+      assert_no_difference('@pirate.send(@association_name).count') do
+        @pirate.update(@alternate_params)
+      end
+    end
+  end
+
+  def test_should_not_destroy_the_associated_model_until_the_parent_is_saved
+    assert_no_difference('@pirate.send(@association_name).count') do
+      @pirate.send(association_setter, @alternate_params[association_getter].merge('baz' => { :id => @child_1.id, '_destroy' => true }))
+    end
+    assert_difference('@pirate.send(@association_name).count', -1) { @pirate.save }
+  end
+
+  def test_should_automatically_enable_autosave_on_the_association
+    assert Pirate.reflect_on_association(@association_name).options[:autosave]
+  end
+
+  def test_validate_presence_of_parent_works_with_inverse_of
+    Man.accepts_nested_attributes_for(:interests)
+    assert_equal :man, Man.reflect_on_association(:interests).options[:inverse_of]
+    assert_equal :interests, Interest.reflect_on_association(:man).options[:inverse_of]
+
+    repair_validations(Interest) do
+      Interest.validates_presence_of(:man)
+      assert_difference 'Man.count' do
+        assert_difference 'Interest.count', 2 do
+          man = Man.create!(:name => 'John',
+                            :interests_attributes => [{:topic=>'Cars'}, {:topic=>'Sports'}])
+          assert_equal 2, man.interests.count
+        end
+      end
+    end
+  end
+
+  def test_can_use_symbols_as_object_identifier
+    @pirate.attributes = { :parrots_attributes => { :foo => { :name => 'Lovely Day' }, :bar => { :name => 'Blown Away' } } }
+    assert_nothing_raised(NoMethodError) { @pirate.save! }
+  end
+
+  def test_numeric_column_changes_from_zero_to_no_empty_string
+    Man.accepts_nested_attributes_for(:interests)
+
+    repair_validations(Interest) do
+      Interest.validates_numericality_of(:zine_id)
+      man = Man.create(name: 'John')
+      interest = man.interests.create(topic: 'bar', zine_id: 0)
+      assert interest.save
+      assert !man.update({interests_attributes: { id: interest.id, zine_id: 'foo' }})
+    end
+  end
+
+  private
+
+  def association_setter
+    @association_setter ||= "#{@association_name}_attributes=".to_sym
+  end
+
+  def association_getter
+    @association_getter ||= "#{@association_name}_attributes".to_sym
+  end
+end
+
+class TestNestedAttributesOnAHasManyAssociation < ActiveRecord::TestCase
+  def setup
+    @association_type = :has_many
+    @association_name = :birds
+
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @pirate.birds.create!(:name => 'Posideons Killer')
+    @pirate.birds.create!(:name => 'Killer bandita Dionne')
+
+    @child_1, @child_2 = @pirate.birds
+
+    @alternate_params = {
+      :birds_attributes => {
+        'foo' => { :id => @child_1.id, :name => 'Grace OMalley' },
+        'bar' => { :id => @child_2.id, :name => 'Privateers Greed' }
+      }
+    }
+  end
+
+  include NestedAttributesOnACollectionAssociationTests
+end
+
+class TestNestedAttributesOnAHasAndBelongsToManyAssociation < ActiveRecord::TestCase
+  def setup
+    @association_type = :has_and_belongs_to_many
+    @association_name = :parrots
+
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    @pirate.parrots.create!(:name => 'Posideons Killer')
+    @pirate.parrots.create!(:name => 'Killer bandita Dionne')
+
+    @child_1, @child_2 = @pirate.parrots
+
+    @alternate_params = {
+      :parrots_attributes => {
+        'foo' => { :id => @child_1.id, :name => 'Grace OMalley' },
+        'bar' => { :id => @child_2.id, :name => 'Privateers Greed' }
+      }
+    }
+  end
+
+  include NestedAttributesOnACollectionAssociationTests
+end
+
+module NestedAttributesLimitTests
+  def teardown
+    Pirate.accepts_nested_attributes_for :parrots, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? }
+  end
+
+  def test_limit_with_less_records
+    @pirate.attributes = { :parrots_attributes => { 'foo' => { :name => 'Big Big Love' } } }
+    assert_difference('Parrot.count') { @pirate.save! }
+  end
+
+  def test_limit_with_number_exact_records
+    @pirate.attributes = { :parrots_attributes => { 'foo' => { :name => 'Lovely Day' }, 'bar' => { :name => 'Blown Away' } } }
+    assert_difference('Parrot.count', 2) { @pirate.save! }
+  end
+
+  def test_limit_with_exceeding_records
+    assert_raises(ActiveRecord::NestedAttributes::TooManyRecords) do
+      @pirate.attributes = { :parrots_attributes => { 'foo' => { :name => 'Lovely Day' },
+                                                      'bar' => { :name => 'Blown Away' },
+                                                      'car' => { :name => 'The Happening' }} }
+    end
+  end
+end
+
+class TestNestedAttributesLimitNumeric < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, :limit => 2
+
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+  end
+
+  include NestedAttributesLimitTests
+end
+
+class TestNestedAttributesLimitSymbol < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, :limit => :parrots_limit
+
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?", :parrots_limit => 2)
+  end
+
+  include NestedAttributesLimitTests
+end
+
+class TestNestedAttributesLimitProc < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, :limit => proc { 2 }
+
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+  end
+
+  include NestedAttributesLimitTests
+end
+
+class TestNestedAttributesWithNonStandardPrimaryKeys < ActiveRecord::TestCase
+  fixtures :owners, :pets
+
+  def setup
+    Owner.accepts_nested_attributes_for :pets, :allow_destroy => true
+
+    @owner = owners(:ashley)
+    @pet1, @pet2 = pets(:chew), pets(:mochi)
+
+    @params = {
+      :pets_attributes => {
+        '0' => { :id => @pet1.id, :name => 'Foo' },
+        '1' => { :id => @pet2.id, :name => 'Bar' }
+      }
+    }
+  end
+
+  def test_should_update_existing_records_with_non_standard_primary_key
+    @owner.update(@params)
+    assert_equal ['Foo', 'Bar'], @owner.pets.map(&:name)
+  end
+
+  def test_attr_accessor_of_child_should_be_value_provided_during_update
+    @owner = owners(:ashley)
+    @pet1 = pets(:chew)
+    attributes = {:pets_attributes => { "1"=> { :id => @pet1.id,
+                                                :name => "Foo2",
+                                                :current_user => "John",
+                                                :_destroy=>true }}}
+    @owner.update(attributes)
+    assert_equal 'John', Pet.after_destroy_output
+  end
+
+end
+
+class TestHasOneAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    @pirate = Pirate.create!(:catchphrase => "My baby takes tha mornin' train!")
+    @ship = @pirate.create_ship(:name => "The good ship Dollypop")
+    @part = @ship.parts.create!(:name => "Mast")
+    @trinket = @part.trinkets.create!(:name => "Necklace")
+  end
+
+  test "when great-grandchild changed in memory, saving parent should save great-grandchild" do
+    @trinket.name = "changed"
+    @pirate.save
+    assert_equal "changed", @trinket.reload.name
+  end
+
+  test "when great-grandchild changed via attributes, saving parent should save great-grandchild" do
+    @pirate.attributes = {:ship_attributes => {:id => @ship.id, :parts_attributes => [{:id => @part.id, :trinkets_attributes => [{:id => @trinket.id, :name => "changed"}]}]}}
+    @pirate.save
+    assert_equal "changed", @trinket.reload.name
+  end
+
+  test "when great-grandchild marked_for_destruction via attributes, saving parent should destroy great-grandchild" do
+    @pirate.attributes = {:ship_attributes => {:id => @ship.id, :parts_attributes => [{:id => @part.id, :trinkets_attributes => [{:id => @trinket.id, :_destroy => true}]}]}}
+    assert_difference('@part.trinkets.count', -1) { @pirate.save }
+  end
+
+  test "when great-grandchild added via attributes, saving parent should create great-grandchild" do
+    @pirate.attributes = {:ship_attributes => {:id => @ship.id, :parts_attributes => [{:id => @part.id, :trinkets_attributes => [{:name => "created"}]}]}}
+    assert_difference('@part.trinkets.count', 1) { @pirate.save }
+  end
+
+  test "when extra records exist for associations, validate (which calls nested_records_changed_for_autosave?) should not load them up" do
+    @trinket.name = "changed"
+    Ship.create!(:pirate => @pirate, :name => "The Black Rock")
+    ShipPart.create!(:ship => @ship, :name => "Stern")
+    assert_no_queries { @pirate.valid? }
+  end
+end
+
+class TestHasManyAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false unless supports_savepoints?
+
+  def setup
+    @ship = Ship.create!(:name => "The good ship Dollypop")
+    @part = @ship.parts.create!(:name => "Mast")
+    @trinket = @part.trinkets.create!(:name => "Necklace")
+  end
+
+  test "if association is not loaded and association record is saved and then in memory record attributes should be saved" do
+    @ship.parts_attributes=[{:id => @part.id,:name =>'Deck'}]
+    assert_equal 1, @ship.association(:parts).target.size
+    assert_equal 'Deck', @ship.parts[0].name
+  end
+
+  test "if association is not loaded and child doesn't change and I am saving a grandchild then in memory record should be used" do
+    @ship.parts_attributes=[{:id => @part.id,:trinkets_attributes =>[{:id => @trinket.id, :name => 'Ruby'}]}]
+    assert_equal 1, @ship.association(:parts).target.size
+    assert_equal 'Mast', @ship.parts[0].name
+    assert_no_difference("@ship.parts[0].association(:trinkets).target.size") do
+      @ship.parts[0].association(:trinkets).target.size
+    end
+    assert_equal 'Ruby', @ship.parts[0].trinkets[0].name
+    @ship.save
+    assert_equal 'Ruby', @ship.parts[0].trinkets[0].name
+  end
+
+  test "when grandchild changed in memory, saving parent should save grandchild" do
+    @trinket.name = "changed"
+    @ship.save
+    assert_equal "changed", @trinket.reload.name
+  end
+
+  test "when grandchild changed via attributes, saving parent should save grandchild" do
+    @ship.attributes = {:parts_attributes => [{:id => @part.id, :trinkets_attributes => [{:id => @trinket.id, :name => "changed"}]}]}
+    @ship.save
+    assert_equal "changed", @trinket.reload.name
+  end
+
+  test "when grandchild marked_for_destruction via attributes, saving parent should destroy grandchild" do
+    @ship.attributes = {:parts_attributes => [{:id => @part.id, :trinkets_attributes => [{:id => @trinket.id, :_destroy => true}]}]}
+    assert_difference('@part.trinkets.count', -1) { @ship.save }
+  end
+
+  test "when grandchild added via attributes, saving parent should create grandchild" do
+    @ship.attributes = {:parts_attributes => [{:id => @part.id, :trinkets_attributes => [{:name => "created"}]}]}
+    assert_difference('@part.trinkets.count', 1) { @ship.save }
+  end
+
+  test "when extra records exist for associations, validate (which calls nested_records_changed_for_autosave?) should not load them up" do
+    @trinket.name = "changed"
+    Ship.create!(:name => "The Black Rock")
+    ShipPart.create!(:ship => @ship, :name => "Stern")
+    assert_no_queries { @ship.valid? }
+  end
+end
diff --git a/activerecord/test/cases/nested_attributes_with_callbacks_test.rb b/activerecord/test/cases/nested_attributes_with_callbacks_test.rb
new file mode 100644
index 0000000000..43a69928b6
--- /dev/null
+++ b/activerecord/test/cases/nested_attributes_with_callbacks_test.rb
@@ -0,0 +1,144 @@
+require "cases/helper"
+require "models/pirate"
+require "models/bird"
+
+class NestedAttributesWithCallbacksTest < ActiveRecord::TestCase
+  Pirate.has_many(:birds_with_add_load,
+                  :class_name => "Bird",
+                  :before_add => proc { |p,b|
+                    @@add_callback_called << b
+                    p.birds_with_add_load.to_a
+                  })
+  Pirate.has_many(:birds_with_add,
+                  :class_name => "Bird",
+                  :before_add => proc { |p,b| @@add_callback_called << b })
+
+  Pirate.accepts_nested_attributes_for(:birds_with_add_load,
+                                       :birds_with_add,
+                                       :allow_destroy => true)
+
+  def setup
+    @@add_callback_called = []
+    @pirate = Pirate.new.tap do |pirate|
+      pirate.catchphrase = "Don't call me!"
+      pirate.birds_attributes = [{:name => 'Bird1'},{:name => 'Bird2'}]
+      pirate.save!
+    end
+    @birds = @pirate.birds.to_a
+  end
+
+  def bird_to_update
+    @birds[0]
+  end
+
+  def bird_to_destroy
+    @birds[1]
+  end
+
+  def existing_birds_attributes
+    @birds.map do |bird|
+      bird.attributes.slice("id","name")
+    end
+  end
+
+  def new_birds
+    @pirate.birds_with_add.to_a - @birds
+  end
+
+  def new_bird_attributes
+     [{'name' => "New Bird"}]
+  end
+
+  def destroy_bird_attributes
+    [{'id' => bird_to_destroy.id.to_s, "_destroy" => true}]
+  end
+
+  def update_new_and_destroy_bird_attributes
+    [{'id' => @birds[0].id.to_s, 'name' => 'New Name'},
+     {'name' => "New Bird"},
+     {'id' => bird_to_destroy.id.to_s, "_destroy" => true}]
+  end
+
+  # Characterizing when :before_add callback is called
+  test ":before_add called for new bird when not loaded" do
+    assert_not @pirate.birds_with_add.loaded?
+    @pirate.birds_with_add_attributes = new_bird_attributes
+    assert_new_bird_with_callback_called
+  end
+
+  test ":before_add called for new bird when loaded" do
+    @pirate.birds_with_add.load_target
+    @pirate.birds_with_add_attributes = new_bird_attributes
+    assert_new_bird_with_callback_called
+  end
+
+  def assert_new_bird_with_callback_called
+    assert_equal(1, new_birds.size)
+    assert_equal(new_birds, @@add_callback_called)
+  end
+
+  test ":before_add not called for identical assignment when not loaded" do
+    assert_not @pirate.birds_with_add.loaded?
+    @pirate.birds_with_add_attributes = existing_birds_attributes
+    assert_callbacks_not_called
+  end
+
+  test ":before_add not called for identical assignment when loaded" do
+    @pirate.birds_with_add.load_target
+    @pirate.birds_with_add_attributes = existing_birds_attributes
+    assert_callbacks_not_called
+  end
+
+  test ":before_add not called for destroy assignment when not loaded" do
+    assert_not @pirate.birds_with_add.loaded?
+    @pirate.birds_with_add_attributes = destroy_bird_attributes
+    assert_callbacks_not_called
+  end
+
+  test ":before_add not called for deletion assignment when loaded" do
+    @pirate.birds_with_add.load_target
+    @pirate.birds_with_add_attributes = destroy_bird_attributes
+    assert_callbacks_not_called
+  end
+
+  def assert_callbacks_not_called
+    assert_empty new_birds
+    assert_empty @@add_callback_called
+  end
+
+  # Ensuring that the records in the association target are updated,
+  # whether the association is loaded before or not
+  test "Assignment updates records in target when not loaded" do
+    assert_not @pirate.birds_with_add.loaded?
+    @pirate.birds_with_add_attributes = update_new_and_destroy_bird_attributes
+    assert_assignment_affects_records_in_target(:birds_with_add)
+  end
+
+  test "Assignment updates records in target when loaded" do
+    @pirate.birds_with_add.load_target
+    @pirate.birds_with_add_attributes = update_new_and_destroy_bird_attributes
+    assert_assignment_affects_records_in_target(:birds_with_add)
+  end
+
+  test("Assignment updates records in target when not loaded" +
+       " and callback loads target") do
+    assert_not @pirate.birds_with_add_load.loaded?
+    @pirate.birds_with_add_load_attributes = update_new_and_destroy_bird_attributes
+    assert_assignment_affects_records_in_target(:birds_with_add_load)
+  end
+
+  test("Assignment updates records in target when loaded" +
+       " and callback loads target") do
+    @pirate.birds_with_add_load.load_target
+    @pirate.birds_with_add_load_attributes = update_new_and_destroy_bird_attributes
+    assert_assignment_affects_records_in_target(:birds_with_add_load)
+  end
+
+  def assert_assignment_affects_records_in_target(association_name)
+    association = @pirate.send(association_name)
+    assert association.detect {|b| b == bird_to_update }.name_changed?,
+      'Update record not updated'
+    assert association.detect {|b| b == bird_to_destroy }.marked_for_destruction?,
+      'Destroy record not marked for destruction'
+  end
+end
diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
new file mode 100644
index 0000000000..2170fe6118
--- /dev/null
+++ b/activerecord/test/cases/persistence_test.rb
@@ -0,0 +1,880 @@
+require "cases/helper"
+require 'models/aircraft'
+require 'models/post'
+require 'models/comment'
+require 'models/author'
+require 'models/topic'
+require 'models/reply'
+require 'models/category'
+require 'models/company'
+require 'models/developer'
+require 'models/project'
+require 'models/minimalistic'
+require 'models/warehouse_thing'
+require 'models/parrot'
+require 'models/minivan'
+require 'models/owner'
+require 'models/person'
+require 'models/pet'
+require 'models/toy'
+require 'rexml/document'
+
+class PersistenceTest < ActiveRecord::TestCase
+  fixtures :topics, :companies, :developers, :projects, :computers, :accounts, :minimalistics, 'warehouse-things', :authors, :author_addresses, :categorizations, :categories, :posts, :minivans, :pets, :toys
+
+  # Oracle UPDATE does not support ORDER BY
+  unless current_adapter?(:OracleAdapter)
+    def test_update_all_ignores_order_without_limit_from_association
+      author = authors(:david)
+      assert_nothing_raised do
+        assert_equal author.posts_with_comments_and_categories.length, author.posts_with_comments_and_categories.update_all([ "body = ?", "bulk update!" ])
+      end
+    end
+
+    def test_update_all_doesnt_ignore_order
+      assert_equal authors(:david).id + 1, authors(:mary).id # make sure there is going to be a duplicate PK error
+      test_update_with_order_succeeds = lambda do |order|
+        begin
+          Author.order(order).update_all('id = id + 1')
+        rescue ActiveRecord::ActiveRecordError
+          false
+        end
+      end
+
+      if test_update_with_order_succeeds.call('id DESC')
+        assert !test_update_with_order_succeeds.call('id ASC') # test that this wasn't a fluke and using an incorrect order results in an exception
+      else
+        # test that we're failing because the current Arel's engine doesn't support UPDATE ORDER BY queries is using subselects instead
+        assert_sql(/\AUPDATE .+ \(SELECT .* ORDER BY id DESC\)\Z/i) do
+          test_update_with_order_succeeds.call('id DESC')
+        end
+      end
+    end
+
+    def test_update_all_with_order_and_limit_updates_subset_only
+      author = authors(:david)
+      assert_nothing_raised do
+        assert_equal 1, author.posts_sorted_by_id_limited.size
+        assert_equal 2, author.posts_sorted_by_id_limited.limit(2).to_a.size
+        assert_equal 1, author.posts_sorted_by_id_limited.update_all([ "body = ?", "bulk update!" ])
+        assert_equal "bulk update!", posts(:welcome).body
+        assert_not_equal "bulk update!", posts(:thinking).body
+      end
+    end
+  end
+
+  def test_update_many
+    topic_data = { 1 => { "content" => "1 updated" }, 2 => { "content" => "2 updated" } }
+    updated = Topic.update(topic_data.keys, topic_data.values)
+
+    assert_equal 2, updated.size
+    assert_equal "1 updated", Topic.find(1).content
+    assert_equal "2 updated", Topic.find(2).content
+  end
+
+  def test_delete_all
+    assert Topic.count > 0
+
+    assert_equal Topic.count, Topic.delete_all
+  end
+
+  def test_delete_all_with_joins_and_where_part_is_hash
+    where_args = {:toys => {:name => 'Bone'}}
+    count = Pet.joins(:toys).where(where_args).count
+
+    assert_equal count, 1
+    assert_equal count, Pet.joins(:toys).where(where_args).delete_all
+  end
+
+  def test_delete_all_with_joins_and_where_part_is_not_hash
+    where_args = ['toys.name = ?', 'Bone']
+    count = Pet.joins(:toys).where(where_args).count
+
+    assert_equal count, 1
+    assert_equal count, Pet.joins(:toys).where(where_args).delete_all
+  end
+
+  def test_increment_attribute
+    assert_equal 50, accounts(:signals37).credit_limit
+    accounts(:signals37).increment! :credit_limit
+    assert_equal 51, accounts(:signals37, :reload).credit_limit
+
+    accounts(:signals37).increment(:credit_limit).increment!(:credit_limit)
+    assert_equal 53, accounts(:signals37, :reload).credit_limit
+  end
+
+  def test_increment_nil_attribute
+    assert_nil topics(:first).parent_id
+    topics(:first).increment! :parent_id
+    assert_equal 1, topics(:first).parent_id
+  end
+
+  def test_increment_attribute_by
+    assert_equal 50, accounts(:signals37).credit_limit
+    accounts(:signals37).increment! :credit_limit, 5
+    assert_equal 55, accounts(:signals37, :reload).credit_limit
+
+    accounts(:signals37).increment(:credit_limit, 1).increment!(:credit_limit, 3)
+    assert_equal 59, accounts(:signals37, :reload).credit_limit
+  end
+
+  def test_destroy_all
+    conditions = "author_name = 'Mary'"
+    topics_by_mary = Topic.all.merge!(:where => conditions, :order => 'id').to_a
+    assert ! topics_by_mary.empty?
+
+    assert_difference('Topic.count', -topics_by_mary.size) do
+      destroyed = Topic.destroy_all(conditions).sort_by(&:id)
+      assert_equal topics_by_mary, destroyed
+      assert destroyed.all? { |topic| topic.frozen? }, "destroyed topics should be frozen"
+    end
+  end
+
+  def test_destroy_many
+    clients = Client.all.merge!(:order => 'id').find([2, 3])
+
+    assert_difference('Client.count', -2) do
+      destroyed = Client.destroy([2, 3]).sort_by(&:id)
+      assert_equal clients, destroyed
+      assert destroyed.all? { |client| client.frozen? }, "destroyed clients should be frozen"
+    end
+  end
+
+  def test_becomes
+    assert_kind_of Reply, topics(:first).becomes(Reply)
+    assert_equal "The First Topic", topics(:first).becomes(Reply).title
+  end
+
+  def test_becomes_includes_errors
+    company = Company.new(:name => nil)
+    assert !company.valid?
+    original_errors = company.errors
+    client = company.becomes(Client)
+    assert_equal original_errors, client.errors
+  end
+
+  def test_dupd_becomes_persists_changes_from_the_original
+    original = topics(:first)
+    copy = original.dup.becomes(Reply)
+    copy.save!
+    assert_equal "The First Topic", Topic.find(copy.id).title
+  end
+
+  def test_becomes_includes_changed_attributes
+    company = Company.new(name: "37signals")
+    client = company.becomes(Client)
+    assert_equal "37signals", client.name
+    assert_equal %w{name}, client.changed
+  end
+
+  def test_delete_many
+    original_count = Topic.count
+    Topic.delete(deleting = [1, 2])
+    assert_equal original_count - deleting.size, Topic.count
+  end
+
+  def test_decrement_attribute
+    assert_equal 50, accounts(:signals37).credit_limit
+
+    accounts(:signals37).decrement!(:credit_limit)
+    assert_equal 49, accounts(:signals37, :reload).credit_limit
+
+    accounts(:signals37).decrement(:credit_limit).decrement!(:credit_limit)
+    assert_equal 47, accounts(:signals37, :reload).credit_limit
+  end
+
+  def test_decrement_attribute_by
+    assert_equal 50, accounts(:signals37).credit_limit
+    accounts(:signals37).decrement! :credit_limit, 5
+    assert_equal 45, accounts(:signals37, :reload).credit_limit
+
+    accounts(:signals37).decrement(:credit_limit, 1).decrement!(:credit_limit, 3)
+    assert_equal 41, accounts(:signals37, :reload).credit_limit
+  end
+
+  def test_create
+    topic = Topic.new
+    topic.title = "New Topic"
+    topic.save
+    topic_reloaded = Topic.find(topic.id)
+    assert_equal("New Topic", topic_reloaded.title)
+  end
+
+  def test_save!
+    topic = Topic.new(:title => "New Topic")
+    assert topic.save!
+
+    reply = WrongReply.new
+    assert_raise(ActiveRecord::RecordInvalid) { reply.save! }
+  end
+
+  def test_save_null_string_attributes
+    topic = Topic.find(1)
+    topic.attributes = { "title" => "null", "author_name" => "null" }
+    topic.save!
+    topic.reload
+    assert_equal("null", topic.title)
+    assert_equal("null", topic.author_name)
+  end
+
+  def test_save_nil_string_attributes
+    topic = Topic.find(1)
+    topic.title = nil
+    topic.save!
+    topic.reload
+    assert_nil topic.title
+  end
+
+  def test_save_for_record_with_only_primary_key
+    minimalistic = Minimalistic.new
+    assert_nothing_raised { minimalistic.save }
+  end
+
+  def test_save_for_record_with_only_primary_key_that_is_provided
+    assert_nothing_raised { Minimalistic.create!(:id => 2) }
+  end
+
+  def test_save_with_duping_of_destroyed_object
+    developer = Developer.first
+    developer.destroy
+    new_developer = developer.dup
+    new_developer.save
+    assert new_developer.persisted?
+    assert_not new_developer.destroyed?
+  end
+
+  def test_create_many
+    topics = Topic.create([ { "title" => "first" }, { "title" => "second" }])
+    assert_equal 2, topics.size
+    assert_equal "first", topics.first.title
+  end
+
+  def test_create_columns_not_equal_attributes
+    topic = Topic.instantiate(
+      'title'          => 'Another New Topic',
+      'does_not_exist' => 'test'
+    )
+    assert_nothing_raised { topic.save }
+  end
+
+  def test_create_through_factory_with_block
+    topic = Topic.create("title" => "New Topic") do |t|
+      t.author_name = "David"
+    end
+    assert_equal("New Topic", topic.title)
+    assert_equal("David", topic.author_name)
+  end
+
+  def test_create_many_through_factory_with_block
+    topics = Topic.create([ { "title" => "first" }, { "title" => "second" }]) do |t|
+      t.author_name = "David"
+    end
+    assert_equal 2, topics.size
+    topic1, topic2 = Topic.find(topics[0].id), Topic.find(topics[1].id)
+    assert_equal "first", topic1.title
+    assert_equal "David", topic1.author_name
+    assert_equal "second", topic2.title
+    assert_equal "David", topic2.author_name
+  end
+
+  def test_update_object
+    topic = Topic.new
+    topic.title = "Another New Topic"
+    topic.written_on = "2003-12-12 23:23:00"
+    topic.save
+    topic_reloaded = Topic.find(topic.id)
+    assert_equal("Another New Topic", topic_reloaded.title)
+
+    topic_reloaded.title = "Updated topic"
+    topic_reloaded.save
+
+    topic_reloaded_again = Topic.find(topic.id)
+
+    assert_equal("Updated topic", topic_reloaded_again.title)
+  end
+
+  def test_update_columns_not_equal_attributes
+    topic = Topic.new
+    topic.title = "Still another topic"
+    topic.save
+
+    topic_reloaded = Topic.instantiate(topic.attributes.merge('does_not_exist' => 'test'))
+    topic_reloaded.title = 'A New Topic'
+    assert_nothing_raised { topic_reloaded.save }
+  end
+
+  def test_update_for_record_with_only_primary_key
+    minimalistic = minimalistics(:first)
+    assert_nothing_raised { minimalistic.save }
+  end
+
+  def test_update_sti_type
+    assert_instance_of Reply, topics(:second)
+
+    topic = topics(:second).becomes!(Topic)
+    assert_instance_of Topic, topic
+    topic.save!
+    assert_instance_of Topic, Topic.find(topic.id)
+  end
+
+  def test_preserve_original_sti_type
+    reply = topics(:second)
+    assert_equal "Reply", reply.type
+
+    topic = reply.becomes(Topic)
+    assert_equal "Reply", reply.type
+
+    assert_instance_of Topic, topic
+    assert_equal "Reply", topic.type
+  end
+
+  def test_update_sti_subclass_type
+    assert_instance_of Topic, topics(:first)
+
+    reply = topics(:first).becomes!(Reply)
+    assert_instance_of Reply, reply
+    reply.save!
+    assert_instance_of Reply, Reply.find(reply.id)
+  end
+
+  def test_update_after_create
+    klass = Class.new(Topic) do
+      def self.name; 'Topic'; end
+      after_create do
+        update_attribute("author_name", "David")
+      end
+    end
+    topic = klass.new
+    topic.title = "Another New Topic"
+    topic.save
+
+    topic_reloaded = Topic.find(topic.id)
+    assert_equal("Another New Topic", topic_reloaded.title)
+    assert_equal("David", topic_reloaded.author_name)
+  end
+
+  def test_delete
+    topic = Topic.find(1)
+    assert_equal topic, topic.delete, 'topic.delete did not return self'
+    assert topic.frozen?, 'topic not frozen after delete'
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(topic.id) }
+  end
+
+  def test_delete_doesnt_run_callbacks
+    Topic.find(1).delete
+    assert_not_nil Topic.find(2)
+  end
+
+  def test_destroy
+    topic = Topic.find(1)
+    assert_equal topic, topic.destroy, 'topic.destroy did not return self'
+    assert topic.frozen?, 'topic not frozen after destroy'
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(topic.id) }
+  end
+
+  def test_destroy!
+    topic = Topic.find(1)
+    assert_equal topic, topic.destroy!, 'topic.destroy! did not return self'
+    assert topic.frozen?, 'topic not frozen after destroy!'
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(topic.id) }
+  end
+
+  def test_record_not_found_exception
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(99999) }
+  end
+
+  def test_update_all
+    assert_equal Topic.count, Topic.update_all("content = 'bulk updated!'")
+    assert_equal "bulk updated!", Topic.find(1).content
+    assert_equal "bulk updated!", Topic.find(2).content
+
+    assert_equal Topic.count, Topic.update_all(['content = ?', 'bulk updated again!'])
+    assert_equal "bulk updated again!", Topic.find(1).content
+    assert_equal "bulk updated again!", Topic.find(2).content
+
+    assert_equal Topic.count, Topic.update_all(['content = ?', nil])
+    assert_nil Topic.find(1).content
+  end
+
+  def test_update_all_with_hash
+    assert_not_nil Topic.find(1).last_read
+    assert_equal Topic.count, Topic.update_all(:content => 'bulk updated with hash!', :last_read => nil)
+    assert_equal "bulk updated with hash!", Topic.find(1).content
+    assert_equal "bulk updated with hash!", Topic.find(2).content
+    assert_nil Topic.find(1).last_read
+    assert_nil Topic.find(2).last_read
+  end
+
+  def test_update_all_with_non_standard_table_name
+    assert_equal 1, WarehouseThing.where(id: 1).update_all(['value = ?', 0])
+    assert_equal 0, WarehouseThing.find(1).value
+  end
+
+  def test_delete_new_record
+    client = Client.new
+    client.delete
+    assert client.frozen?
+  end
+
+  def test_delete_record_with_associations
+    client = Client.find(3)
+    client.delete
+    assert client.frozen?
+    assert_kind_of Firm, client.firm
+    assert_raise(RuntimeError) { client.name = "something else" }
+  end
+
+  def test_destroy_new_record
+    client = Client.new
+    client.destroy
+    assert client.frozen?
+  end
+
+  def test_destroy_record_with_associations
+    client = Client.find(3)
+    client.destroy
+    assert client.frozen?
+    assert_kind_of Firm, client.firm
+    assert_raise(RuntimeError) { client.name = "something else" }
+  end
+
+  def test_update_attribute
+    assert !Topic.find(1).approved?
+    Topic.find(1).update_attribute("approved", true)
+    assert Topic.find(1).approved?
+
+    Topic.find(1).update_attribute(:approved, false)
+    assert !Topic.find(1).approved?
+  end
+
+  def test_update_attribute_for_readonly_attribute
+    minivan = Minivan.find('m1')
+    assert_raises(ActiveRecord::ActiveRecordError) { minivan.update_attribute(:color, 'black') }
+  end
+
+  def test_update_attribute_with_one_updated
+    t = Topic.first
+    t.update_attribute(:title, 'super_title')
+    assert_equal 'super_title', t.title
+    assert !t.changed?, "topic should not have changed"
+    assert !t.title_changed?, "title should not have changed"
+    assert_nil t.title_change, 'title change should be nil'
+
+    t.reload
+    assert_equal 'super_title', t.title
+  end
+
+  def test_update_attribute_for_updated_at_on
+    developer = Developer.find(1)
+    prev_month = Time.now.prev_month.change(usec: 0)
+
+    developer.update_attribute(:updated_at, prev_month)
+    assert_equal prev_month, developer.updated_at
+
+    developer.update_attribute(:salary, 80001)
+    assert_not_equal prev_month, developer.updated_at
+
+    developer.reload
+    assert_not_equal prev_month, developer.updated_at
+  end
+
+  def test_update_column
+    topic = Topic.find(1)
+    topic.update_column("approved", true)
+    assert topic.approved?
+    topic.reload
+    assert topic.approved?
+
+    topic.update_column(:approved, false)
+    assert !topic.approved?
+    topic.reload
+    assert !topic.approved?
+  end
+
+  def test_update_column_should_not_use_setter_method
+    dev = Developer.find(1)
+    dev.instance_eval { def salary=(value); write_attribute(:salary, value * 2); end }
+
+    dev.update_column(:salary, 80000)
+    assert_equal 80000, dev.salary
+
+    dev.reload
+    assert_equal 80000, dev.salary
+  end
+
+  def test_update_column_should_raise_exception_if_new_record
+    topic = Topic.new
+    assert_raises(ActiveRecord::ActiveRecordError) { topic.update_column("approved", false) }
+  end
+
+  def test_update_column_should_not_leave_the_object_dirty
+    topic = Topic.find(1)
+    topic.update_column("content", "--- Have a nice day\n...\n")
+
+    topic.reload
+    topic.update_column(:content, "--- You too\n...\n")
+    assert_equal [], topic.changed
+
+    topic.reload
+    topic.update_column("content", "--- Have a nice day\n...\n")
+    assert_equal [], topic.changed
+  end
+
+  def test_update_column_with_model_having_primary_key_other_than_id
+    minivan = Minivan.find('m1')
+    new_name = 'sebavan'
+
+    minivan.update_column(:name, new_name)
+    assert_equal new_name, minivan.name
+  end
+
+  def test_update_column_for_readonly_attribute
+    minivan = Minivan.find('m1')
+    prev_color = minivan.color
+    assert_raises(ActiveRecord::ActiveRecordError) { minivan.update_column(:color, 'black') }
+    assert_equal prev_color, minivan.color
+  end
+
+  def test_update_column_should_not_modify_updated_at
+    developer = Developer.find(1)
+    prev_month = Time.now.prev_month.change(usec: 0)
+
+    developer.update_column(:updated_at, prev_month)
+    assert_equal prev_month, developer.updated_at
+
+    developer.update_column(:salary, 80001)
+    assert_equal prev_month, developer.updated_at
+
+    developer.reload
+    assert_equal prev_month.to_i, developer.updated_at.to_i
+  end
+
+  def test_update_column_with_one_changed_and_one_updated
+    t = Topic.order('id').limit(1).first
+    author_name = t.author_name
+    t.author_name = 'John'
+    t.update_column(:title, 'super_title')
+    assert_equal 'John', t.author_name
+    assert_equal 'super_title', t.title
+    assert t.changed?, "topic should have changed"
+    assert t.author_name_changed?, "author_name should have changed"
+
+    t.reload
+    assert_equal author_name, t.author_name
+    assert_equal 'super_title', t.title
+  end
+
+  def test_update_column_with_default_scope
+    developer = DeveloperCalledDavid.first
+    developer.name = 'John'
+    developer.save!
+
+    assert developer.update_column(:name, 'Will'), 'did not update record due to default scope'
+  end
+
+  def test_update_columns
+    topic = Topic.find(1)
+    topic.update_columns({ "approved" => true, title: "Sebastian Topic" })
+    assert topic.approved?
+    assert_equal "Sebastian Topic", topic.title
+    topic.reload
+    assert topic.approved?
+    assert_equal "Sebastian Topic", topic.title
+  end
+
+  def test_update_columns_should_not_use_setter_method
+    dev = Developer.find(1)
+    dev.instance_eval { def salary=(value); write_attribute(:salary, value * 2); end }
+
+    dev.update_columns(salary: 80000)
+    assert_equal 80000, dev.salary
+
+    dev.reload
+    assert_equal 80000, dev.salary
+  end
+
+  def test_update_columns_should_raise_exception_if_new_record
+    topic = Topic.new
+    assert_raises(ActiveRecord::ActiveRecordError) { topic.update_columns({ approved: false }) }
+  end
+
+  def test_update_columns_should_not_leave_the_object_dirty
+    topic = Topic.find(1)
+    topic.update({ "content" => "--- Have a nice day\n...\n", :author_name => "Jose" })
+
+    topic.reload
+    topic.update_columns({ content: "--- You too\n...\n", "author_name" => "Sebastian" })
+    assert_equal [], topic.changed
+
+    topic.reload
+    topic.update_columns({ content: "--- Have a nice day\n...\n", author_name: "Jose" })
+    assert_equal [], topic.changed
+  end
+
+  def test_update_columns_with_model_having_primary_key_other_than_id
+    minivan = Minivan.find('m1')
+    new_name = 'sebavan'
+
+    minivan.update_columns(name: new_name)
+    assert_equal new_name, minivan.name
+  end
+
+  def test_update_columns_with_one_readonly_attribute
+    minivan = Minivan.find('m1')
+    prev_color = minivan.color
+    prev_name = minivan.name
+    assert_raises(ActiveRecord::ActiveRecordError) { minivan.update_columns({ name: "My old minivan", color: 'black' }) }
+    assert_equal prev_color, minivan.color
+    assert_equal prev_name, minivan.name
+
+    minivan.reload
+    assert_equal prev_color, minivan.color
+    assert_equal prev_name, minivan.name
+  end
+
+  def test_update_columns_should_not_modify_updated_at
+    developer = Developer.find(1)
+    prev_month = Time.now.prev_month.change(usec: 0)
+
+    developer.update_columns(updated_at: prev_month)
+    assert_equal prev_month, developer.updated_at
+
+    developer.update_columns(salary: 80000)
+    assert_equal prev_month, developer.updated_at
+    assert_equal 80000, developer.salary
+
+    developer.reload
+    assert_equal prev_month.to_i, developer.updated_at.to_i
+    assert_equal 80000, developer.salary
+  end
+
+  def test_update_columns_with_one_changed_and_one_updated
+    t = Topic.order('id').limit(1).first
+    author_name = t.author_name
+    t.author_name = 'John'
+    t.update_columns(title: 'super_title')
+    assert_equal 'John', t.author_name
+    assert_equal 'super_title', t.title
+    assert t.changed?, "topic should have changed"
+    assert t.author_name_changed?, "author_name should have changed"
+
+    t.reload
+    assert_equal author_name, t.author_name
+    assert_equal 'super_title', t.title
+  end
+
+  def test_update_columns_changing_id
+    topic = Topic.find(1)
+    topic.update_columns(id: 123)
+    assert_equal 123, topic.id
+    topic.reload
+    assert_equal 123, topic.id
+  end
+
+  def test_update_columns_returns_boolean
+    topic = Topic.find(1)
+    assert_equal true, topic.update_columns(title: "New title")
+  end
+
+  def test_update_columns_with_default_scope
+    developer = DeveloperCalledDavid.first
+    developer.name = 'John'
+    developer.save!
+
+    assert developer.update_columns(name: 'Will'), 'did not update record due to default scope'
+  end
+
+  def test_update
+    topic = Topic.find(1)
+    assert !topic.approved?
+    assert_equal "The First Topic", topic.title
+
+    topic.update("approved" => true, "title" => "The First Topic Updated")
+    topic.reload
+    assert topic.approved?
+    assert_equal "The First Topic Updated", topic.title
+
+    topic.update(approved: false, title: "The First Topic")
+    topic.reload
+    assert !topic.approved?
+    assert_equal "The First Topic", topic.title
+  end
+
+  def test_update_attributes
+    topic = Topic.find(1)
+    assert !topic.approved?
+    assert_equal "The First Topic", topic.title
+
+    topic.update_attributes("approved" => true, "title" => "The First Topic Updated")
+    topic.reload
+    assert topic.approved?
+    assert_equal "The First Topic Updated", topic.title
+
+    topic.update_attributes(approved: false, title: "The First Topic")
+    topic.reload
+    assert !topic.approved?
+    assert_equal "The First Topic", topic.title
+
+    assert_raise(ActiveRecord::RecordNotUnique, ActiveRecord::StatementInvalid) do
+      topic.update_attributes(id: 3, title: "Hm is it possible?")
+    end
+    assert_not_equal "Hm is it possible?", Topic.find(3).title
+
+    topic.update_attributes(id: 1234)
+    assert_nothing_raised { topic.reload }
+    assert_equal topic.title, Topic.find(1234).title
+  end
+
+  def test_update_attributes_parameters
+    topic = Topic.find(1)
+    assert_nothing_raised do
+      topic.update_attributes({})
+    end
+
+    assert_raises(ArgumentError) do
+      topic.update_attributes(nil)
+    end
+  end
+
+  def test_update!
+    Reply.validates_presence_of(:title)
+    reply = Reply.find(2)
+    assert_equal "The Second Topic of the day", reply.title
+    assert_equal "Have a nice day", reply.content
+
+    reply.update!("title" => "The Second Topic of the day updated", "content" => "Have a nice evening")
+    reply.reload
+    assert_equal "The Second Topic of the day updated", reply.title
+    assert_equal "Have a nice evening", reply.content
+
+    reply.update!(title: "The Second Topic of the day", content: "Have a nice day")
+    reply.reload
+    assert_equal "The Second Topic of the day", reply.title
+    assert_equal "Have a nice day", reply.content
+
+    assert_raise(ActiveRecord::RecordInvalid) { reply.update!(title: nil, content: "Have a nice evening") }
+  ensure
+    Reply.clear_validators!
+  end
+
+  def test_update_attributes!
+    Reply.validates_presence_of(:title)
+    reply = Reply.find(2)
+    assert_equal "The Second Topic of the day", reply.title
+    assert_equal "Have a nice day", reply.content
+
+    reply.update_attributes!("title" => "The Second Topic of the day updated", "content" => "Have a nice evening")
+    reply.reload
+    assert_equal "The Second Topic of the day updated", reply.title
+    assert_equal "Have a nice evening", reply.content
+
+    reply.update_attributes!(title: "The Second Topic of the day", content: "Have a nice day")
+    reply.reload
+    assert_equal "The Second Topic of the day", reply.title
+    assert_equal "Have a nice day", reply.content
+
+    assert_raise(ActiveRecord::RecordInvalid) { reply.update_attributes!(title: nil, content: "Have a nice evening") }
+  ensure
+    Reply.clear_validators!
+  end
+
+  def test_destroyed_returns_boolean
+    developer = Developer.first
+    assert_equal false, developer.destroyed?
+    developer.destroy
+    assert_equal true, developer.destroyed?
+
+    developer = Developer.last
+    assert_equal false, developer.destroyed?
+    developer.delete
+    assert_equal true, developer.destroyed?
+  end
+
+  def test_persisted_returns_boolean
+    developer = Developer.new(:name => "Jose")
+    assert_equal false, developer.persisted?
+    developer.save!
+    assert_equal true, developer.persisted?
+
+    developer = Developer.first
+    assert_equal true, developer.persisted?
+    developer.destroy
+    assert_equal false, developer.persisted?
+
+    developer = Developer.last
+    assert_equal true, developer.persisted?
+    developer.delete
+    assert_equal false, developer.persisted?
+  end
+
+  def test_class_level_destroy
+    should_be_destroyed_reply = Reply.create("title" => "hello", "content" => "world")
+    Topic.find(1).replies << should_be_destroyed_reply
+
+    Topic.destroy(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(1) }
+    assert_raise(ActiveRecord::RecordNotFound) { Reply.find(should_be_destroyed_reply.id) }
+  end
+
+  def test_class_level_delete
+    should_be_destroyed_reply = Reply.create("title" => "hello", "content" => "world")
+    Topic.find(1).replies << should_be_destroyed_reply
+
+    Topic.delete(1)
+    assert_raise(ActiveRecord::RecordNotFound) { Topic.find(1) }
+    assert_nothing_raised { Reply.find(should_be_destroyed_reply.id) }
+  end
+
+  def test_create_with_custom_timestamps
+    custom_datetime = 1.hour.ago.beginning_of_day
+
+    %w(created_at created_on updated_at updated_on).each do |attribute|
+      parrot = LiveParrot.create(:name => "colombian", attribute => custom_datetime)
+      assert_equal custom_datetime, parrot[attribute]
+    end
+  end
+
+  def test_persist_inherited_class_with_different_table_name
+    minimalistic_aircrafts = Class.new(Minimalistic) do
+      self.table_name = "aircraft"
+    end
+
+    assert_difference "Aircraft.count", 1 do
+      aircraft = minimalistic_aircrafts.create(name: "Wright Flyer")
+      aircraft.name = "Wright Glider"
+      aircraft.save
+    end
+
+    assert_equal "Wright Glider", Aircraft.last.name
+  end
+
+  def test_instantiate_creates_a_new_instance
+    post = Post.instantiate("title" => "appropriate documentation", "type" => "SpecialPost")
+    assert_equal "appropriate documentation", post.title
+    assert_instance_of SpecialPost, post
+
+    # body was not initialized
+    assert_raises ActiveModel::MissingAttributeError do
+      post.body
+    end
+  end
+
+  def test_reload_removes_custom_selects
+    post = Post.select('posts.*, 1 as wibble').last!
+
+    assert_equal 1, post[:wibble]
+    assert_nil post.reload[:wibble]
+  end
+
+  def test_find_via_reload
+    post = Post.new
+
+    assert post.new_record?
+
+    post.id = 1
+    post.reload
+
+    assert_equal "Welcome to the weblog", post.title
+    assert_not post.new_record?
+  end
+end
diff --git a/activerecord/test/cases/pooled_connections_test.rb b/activerecord/test/cases/pooled_connections_test.rb
new file mode 100644
index 0000000000..8eea10143f
--- /dev/null
+++ b/activerecord/test/cases/pooled_connections_test.rb
@@ -0,0 +1,51 @@
+require "cases/helper"
+require "models/project"
+require "timeout"
+
+class PooledConnectionsTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  def setup
+    @per_test_teardown = []
+    @connection = ActiveRecord::Base.remove_connection
+  end
+
+  teardown do
+    ActiveRecord::Base.clear_all_connections!
+    ActiveRecord::Base.establish_connection(@connection)
+    @per_test_teardown.each {|td| td.call }
+  end
+
+  # Will deadlock due to lack of Monitor timeouts in 1.9
+  def checkout_checkin_connections(pool_size, threads)
+    ActiveRecord::Base.establish_connection(@connection.merge({:pool => pool_size, :checkout_timeout => 0.5}))
+    @connection_count = 0
+    @timed_out = 0
+    threads.times do
+      Thread.new do
+        begin
+          conn = ActiveRecord::Base.connection_pool.checkout
+          sleep 0.1
+          ActiveRecord::Base.connection_pool.checkin conn
+          @connection_count += 1
+        rescue ActiveRecord::ConnectionTimeoutError
+          @timed_out += 1
+        end
+      end.join
+    end
+  end
+
+  def test_pooled_connection_checkin_one
+    checkout_checkin_connections 1, 2
+    assert_equal 2, @connection_count
+    assert_equal 0, @timed_out
+    assert_equal 1, ActiveRecord::Base.connection_pool.connections.size
+  end
+
+
+  private
+
+  def add_record(name)
+    ActiveRecord::Base.connection_pool.with_connection { Project.create! :name => name }
+  end
+end unless in_memory_db?
diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
new file mode 100644
index 0000000000..f19a6ea5e3
--- /dev/null
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -0,0 +1,236 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/reply'
+require 'models/subscriber'
+require 'models/movie'
+require 'models/keyboard'
+require 'models/mixed_case_monkey'
+require 'models/dashboard'
+
+class PrimaryKeysTest < ActiveRecord::TestCase
+  fixtures :topics, :subscribers, :movies, :mixed_case_monkeys
+
+  def test_to_key_with_default_primary_key
+    topic = Topic.new
+    assert_nil topic.to_key
+    topic = Topic.find(1)
+    assert_equal [1], topic.to_key
+  end
+
+  def test_to_key_with_customized_primary_key
+    keyboard = Keyboard.new
+    assert_nil keyboard.to_key
+    keyboard.save
+    assert_equal keyboard.to_key, [keyboard.id]
+  end
+
+  def test_read_attribute_with_custom_primary_key
+    keyboard = Keyboard.create!
+    assert_equal keyboard.key_number, keyboard.read_attribute(:id)
+  end
+
+  def test_to_key_with_primary_key_after_destroy
+    topic = Topic.find(1)
+    topic.destroy
+    assert_equal [1], topic.to_key
+  end
+
+  def test_integer_key
+    topic = Topic.find(1)
+    assert_equal(topics(:first).author_name, topic.author_name)
+    topic = Topic.find(2)
+    assert_equal(topics(:second).author_name, topic.author_name)
+
+    topic = Topic.new
+    topic.title = "New Topic"
+    assert_nil topic.id
+    assert_nothing_raised { topic.save! }
+    id = topic.id
+
+    topicReloaded = Topic.find(id)
+    assert_equal("New Topic", topicReloaded.title)
+  end
+
+  def test_customized_primary_key_auto_assigns_on_save
+    Keyboard.delete_all
+    keyboard = Keyboard.new(:name => 'HHKB')
+    assert_nothing_raised { keyboard.save! }
+    assert_equal keyboard.id, Keyboard.find_by_name('HHKB').id
+  end
+
+  def test_customized_primary_key_can_be_get_before_saving
+    keyboard = Keyboard.new
+    assert_nil keyboard.id
+    assert_nothing_raised { assert_nil keyboard.key_number }
+  end
+
+  def test_customized_string_primary_key_settable_before_save
+    subscriber = Subscriber.new
+    assert_nothing_raised { subscriber.id = 'webster123' }
+    assert_equal 'webster123', subscriber.id
+    assert_equal 'webster123', subscriber.nick
+  end
+
+  def test_string_key
+    subscriber = Subscriber.find(subscribers(:first).nick)
+    assert_equal(subscribers(:first).name, subscriber.name)
+    subscriber = Subscriber.find(subscribers(:second).nick)
+    assert_equal(subscribers(:second).name, subscriber.name)
+
+    subscriber = Subscriber.new
+    subscriber.id = "jdoe"
+    assert_equal("jdoe", subscriber.id)
+    subscriber.name = "John Doe"
+    assert_nothing_raised { subscriber.save! }
+    assert_equal("jdoe", subscriber.id)
+
+    subscriberReloaded = Subscriber.find("jdoe")
+    assert_equal("John Doe", subscriberReloaded.name)
+  end
+
+  def test_find_with_more_than_one_string_key
+    assert_equal 2, Subscriber.find(subscribers(:first).nick, subscribers(:second).nick).length
+  end
+
+  def test_primary_key_prefix
+    old_primary_key_prefix_type = ActiveRecord::Base.primary_key_prefix_type
+    ActiveRecord::Base.primary_key_prefix_type = :table_name
+    Topic.reset_primary_key
+    assert_equal "topicid", Topic.primary_key
+
+    ActiveRecord::Base.primary_key_prefix_type = :table_name_with_underscore
+    Topic.reset_primary_key
+    assert_equal "topic_id", Topic.primary_key
+
+    ActiveRecord::Base.primary_key_prefix_type = nil
+    Topic.reset_primary_key
+    assert_equal "id", Topic.primary_key
+  ensure
+    ActiveRecord::Base.primary_key_prefix_type = old_primary_key_prefix_type
+  end
+
+  def test_delete_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.delete(1) }
+  end
+  def test_update_counters_should_quote_pkey_and_quote_counter_columns
+    assert_nothing_raised { MixedCaseMonkey.update_counters(1, :fleaCount => 99) }
+  end
+  def test_find_with_one_id_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1) }
+  end
+  def test_find_with_multiple_ids_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find([1,2]) }
+  end
+  def test_instance_update_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1).save }
+  end
+  def test_instance_destroy_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1).destroy }
+  end
+
+  def test_supports_primary_key
+    assert_nothing_raised NoMethodError do
+      ActiveRecord::Base.connection.supports_primary_key?
+    end
+  end
+
+  def test_primary_key_returns_value_if_it_exists
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = 'developers'
+    end
+
+    if ActiveRecord::Base.connection.supports_primary_key?
+      assert_equal 'id', klass.primary_key
+    end
+  end
+
+  def test_primary_key_returns_nil_if_it_does_not_exist
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = 'developers_projects'
+    end
+
+    if ActiveRecord::Base.connection.supports_primary_key?
+      assert_nil klass.primary_key
+    end
+  end
+
+  def test_quoted_primary_key_after_set_primary_key
+    k = Class.new( ActiveRecord::Base )
+    assert_equal k.connection.quote_column_name("id"), k.quoted_primary_key
+    k.primary_key = "foo"
+    assert_equal k.connection.quote_column_name("foo"), k.quoted_primary_key
+  end
+
+  def test_auto_detect_primary_key_from_schema
+    MixedCaseMonkey.reset_primary_key
+    assert_equal "monkeyID", MixedCaseMonkey.primary_key
+  end
+
+  def test_primary_key_update_with_custom_key_name
+    dashboard = Dashboard.create!(dashboard_id: '1')
+    dashboard.id = '2'
+    dashboard.save!
+
+    dashboard = Dashboard.first
+    assert_equal '2', dashboard.id
+  end
+end
+
+class PrimaryKeyWithNoConnectionTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  unless in_memory_db?
+    def test_set_primary_key_with_no_connection
+      connection = ActiveRecord::Base.remove_connection
+
+      model = Class.new(ActiveRecord::Base)
+      model.primary_key = 'foo'
+
+      assert_equal 'foo', model.primary_key
+
+      ActiveRecord::Base.establish_connection(connection)
+
+      assert_equal 'foo', model.primary_key
+    end
+  end
+end
+
+if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+  class PrimaryKeyWithAnsiQuotesTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    def test_primary_key_method_with_ansi_quotes
+      con = ActiveRecord::Base.connection
+      con.execute("SET SESSION sql_mode='ANSI_QUOTES'")
+      assert_equal "id", con.primary_key("topics")
+    ensure
+      con.reconnect!
+    end
+  end
+end
+
+if current_adapter?(:PostgreSQLAdapter)
+  class PrimaryKeyBigSerialTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    class Widget < ActiveRecord::Base
+    end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      @connection.create_table(:widgets, id: :bigserial) { |t| }
+    end
+
+    teardown do
+      @connection.drop_table :widgets
+    end
+
+    def test_bigserial_primary_key
+      assert_equal "id", Widget.primary_key
+      assert_equal :integer, Widget.columns_hash[Widget.primary_key].type
+
+      widget = Widget.create!
+      assert_not_nil widget.id
+    end
+  end
+end
diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
new file mode 100644
index 0000000000..9d89d6a1e8
--- /dev/null
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -0,0 +1,290 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/task'
+require 'models/category'
+require 'models/post'
+require 'rack'
+
+class QueryCacheTest < ActiveRecord::TestCase
+  fixtures :tasks, :topics, :categories, :posts, :categories_posts
+
+  teardown do
+    Task.connection.clear_query_cache
+    ActiveRecord::Base.connection.disable_query_cache!
+  end
+
+  def test_exceptional_middleware_clears_and_disables_cache_on_error
+    assert !ActiveRecord::Base.connection.query_cache_enabled, 'cache off'
+
+    mw = ActiveRecord::QueryCache.new lambda { |env|
+      Task.find 1
+      Task.find 1
+      assert_equal 1, ActiveRecord::Base.connection.query_cache.length
+      raise "lol borked"
+    }
+    assert_raises(RuntimeError) { mw.call({}) }
+
+    assert_equal 0, ActiveRecord::Base.connection.query_cache.length
+    assert !ActiveRecord::Base.connection.query_cache_enabled, 'cache off'
+  end
+
+  def test_exceptional_middleware_leaves_enabled_cache_alone
+    ActiveRecord::Base.connection.enable_query_cache!
+
+    mw = ActiveRecord::QueryCache.new lambda { |env|
+      raise "lol borked"
+    }
+    assert_raises(RuntimeError) { mw.call({}) }
+
+    assert ActiveRecord::Base.connection.query_cache_enabled, 'cache on'
+  end
+
+  def test_exceptional_middleware_assigns_original_connection_id_on_error
+    connection_id = ActiveRecord::Base.connection_id
+
+    mw = ActiveRecord::QueryCache.new lambda { |env|
+      ActiveRecord::Base.connection_id = self.object_id
+      raise "lol borked"
+    }
+    assert_raises(RuntimeError) { mw.call({}) }
+
+    assert_equal connection_id, ActiveRecord::Base.connection_id
+  end
+
+  def test_middleware_delegates
+    called = false
+    mw = ActiveRecord::QueryCache.new lambda { |env|
+      called = true
+      [200, {}, nil]
+    }
+    mw.call({})
+    assert called, 'middleware should delegate'
+  end
+
+  def test_middleware_caches
+    mw = ActiveRecord::QueryCache.new lambda { |env|
+      Task.find 1
+      Task.find 1
+      assert_equal 1, ActiveRecord::Base.connection.query_cache.length
+      [200, {}, nil]
+    }
+    mw.call({})
+  end
+
+  def test_cache_enabled_during_call
+    assert !ActiveRecord::Base.connection.query_cache_enabled, 'cache off'
+
+    mw = ActiveRecord::QueryCache.new lambda { |env|
+      assert ActiveRecord::Base.connection.query_cache_enabled, 'cache on'
+      [200, {}, nil]
+    }
+    mw.call({})
+  end
+
+  def test_cache_on_during_body_write
+    streaming = Class.new do
+      def each
+        yield ActiveRecord::Base.connection.query_cache_enabled
+      end
+    end
+
+    mw = ActiveRecord::QueryCache.new lambda { |env|
+      [200, {}, streaming.new]
+    }
+    body = mw.call({}).last
+    body.each { |x| assert x, 'cache should be on' }
+    body.close
+    assert !ActiveRecord::Base.connection.query_cache_enabled, 'cache disabled'
+  end
+
+  def test_cache_off_after_close
+    mw = ActiveRecord::QueryCache.new lambda { |env| [200, {}, nil] }
+    body = mw.call({}).last
+
+    assert ActiveRecord::Base.connection.query_cache_enabled, 'cache enabled'
+    body.close
+    assert !ActiveRecord::Base.connection.query_cache_enabled, 'cache disabled'
+  end
+
+  def test_cache_clear_after_close
+    mw = ActiveRecord::QueryCache.new lambda { |env|
+      Post.first
+      [200, {}, nil]
+    }
+    body = mw.call({}).last
+
+    assert !ActiveRecord::Base.connection.query_cache.empty?, 'cache not empty'
+    body.close
+    assert ActiveRecord::Base.connection.query_cache.empty?, 'cache should be empty'
+  end
+
+  def test_cache_passing_a_relation
+    post = Post.first
+    Post.cache do
+      query = post.categories.select(:post_id)
+      assert Post.connection.select_all(query).is_a?(ActiveRecord::Result)
+    end
+  end
+
+  def test_find_queries
+    assert_queries(2) { Task.find(1); Task.find(1) }
+  end
+
+  def test_find_queries_with_cache
+    Task.cache do
+      assert_queries(1) { Task.find(1); Task.find(1) }
+    end
+  end
+
+  def test_find_queries_with_cache_multi_record
+    Task.cache do
+      assert_queries(2) { Task.find(1); Task.find(1); Task.find(2) }
+    end
+  end
+
+  def test_find_queries_with_multi_cache_blocks
+    Task.cache do
+      Task.cache do
+        assert_queries(2) { Task.find(1); Task.find(2) }
+      end
+      assert_queries(0) { Task.find(1); Task.find(1); Task.find(2) }
+    end
+  end
+
+  def test_count_queries_with_cache
+    Task.cache do
+      assert_queries(1) { Task.count; Task.count }
+    end
+  end
+
+  def test_query_cache_dups_results_correctly
+    Task.cache do
+      now  = Time.now.utc
+      task = Task.find 1
+      assert_not_equal now, task.starting
+      task.starting = now
+      task.reload
+      assert_not_equal now, task.starting
+    end
+  end
+
+  def test_cache_is_flat
+    Task.cache do
+      Topic.columns # don't count this query
+      assert_queries(1) { Topic.find(1); Topic.find(1); }
+    end
+
+    ActiveRecord::Base.cache do
+      assert_queries(1) { Task.find(1); Task.find(1) }
+    end
+  end
+
+  def test_cache_does_not_wrap_string_results_in_arrays
+    Task.cache do
+      # Oracle adapter returns count() as Fixnum or Float
+      if current_adapter?(:OracleAdapter)
+        assert_kind_of Numeric, Task.connection.select_value("SELECT count(*) AS count_all FROM tasks")
+      elsif current_adapter?(:SQLite3Adapter, :Mysql2Adapter)
+        # Future versions of the sqlite3 adapter will return numeric
+        assert_instance_of Fixnum,
+         Task.connection.select_value("SELECT count(*) AS count_all FROM tasks")
+      else
+        assert_instance_of String, Task.connection.select_value("SELECT count(*) AS count_all FROM tasks")
+      end
+    end
+  end
+
+  def test_cache_is_ignored_for_locked_relations
+    task = Task.find 1
+
+    Task.cache do
+      assert_queries(2) { task.lock!; task.lock! }
+    end
+  end
+
+  def test_cache_is_available_when_connection_is_connected
+    conf = ActiveRecord::Base.configurations
+
+    ActiveRecord::Base.configurations = {}
+    Task.cache do
+      assert_queries(1) { Task.find(1); Task.find(1) }
+    end
+  ensure
+    ActiveRecord::Base.configurations = conf
+  end
+end
+
+class QueryCacheExpiryTest < ActiveRecord::TestCase
+  fixtures :tasks, :posts, :categories, :categories_posts
+
+  def test_cache_gets_cleared_after_migration
+    # warm the cache
+    Post.find(1)
+
+    # change the column definition
+    Post.connection.change_column :posts, :title, :string, limit: 80
+    assert_nothing_raised { Post.find(1) }
+
+    # restore the old definition
+    Post.connection.change_column :posts, :title, :string
+  end
+
+  def test_find
+    Task.connection.expects(:clear_query_cache).times(1)
+
+    assert !Task.connection.query_cache_enabled
+    Task.cache do
+      assert Task.connection.query_cache_enabled
+      Task.find(1)
+
+      Task.uncached do
+        assert !Task.connection.query_cache_enabled
+        Task.find(1)
+      end
+
+      assert Task.connection.query_cache_enabled
+    end
+    assert !Task.connection.query_cache_enabled
+  end
+
+  def test_update
+    Task.connection.expects(:clear_query_cache).times(2)
+    Task.cache do
+      task = Task.find(1)
+      task.starting = Time.now.utc
+      task.save!
+    end
+  end
+
+  def test_destroy
+    Task.connection.expects(:clear_query_cache).times(2)
+    Task.cache do
+      Task.find(1).destroy
+    end
+  end
+
+  def test_insert
+    ActiveRecord::Base.connection.expects(:clear_query_cache).times(2)
+    Task.cache do
+      Task.create!
+    end
+  end
+
+  def test_cache_is_expired_by_habtm_update
+    ActiveRecord::Base.connection.expects(:clear_query_cache).times(2)
+    ActiveRecord::Base.cache do
+      c = Category.first
+      p = Post.first
+      p.categories << c
+    end
+  end
+
+  def test_cache_is_expired_by_habtm_delete
+    ActiveRecord::Base.connection.expects(:clear_query_cache).times(2)
+    ActiveRecord::Base.cache do
+      p = Post.find(1)
+      assert p.categories.any?
+      p.categories.delete_all
+    end
+  end
+end
diff --git a/activerecord/test/cases/quoting_test.rb b/activerecord/test/cases/quoting_test.rb
new file mode 100644
index 0000000000..1d6ae2f67f
--- /dev/null
+++ b/activerecord/test/cases/quoting_test.rb
@@ -0,0 +1,156 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class QuotingTest < ActiveRecord::TestCase
+      def setup
+        @quoter = Class.new { include Quoting }.new
+      end
+
+      def test_quoted_true
+        assert_equal "'t'", @quoter.quoted_true
+      end
+
+      def test_quoted_false
+        assert_equal "'f'", @quoter.quoted_false
+      end
+
+      def test_quote_column_name
+        assert_equal "foo", @quoter.quote_column_name('foo')
+      end
+
+      def test_quote_table_name
+        assert_equal "foo", @quoter.quote_table_name('foo')
+      end
+
+      def test_quote_table_name_calls_quote_column_name
+        @quoter.extend(Module.new {
+          def quote_column_name(string)
+            'lol'
+          end
+        })
+        assert_equal 'lol', @quoter.quote_table_name('foo')
+      end
+
+      def test_quote_string
+        assert_equal "''", @quoter.quote_string("'")
+        assert_equal "\\\\", @quoter.quote_string("\\")
+        assert_equal "hi''i", @quoter.quote_string("hi'i")
+        assert_equal "hi\\\\i", @quoter.quote_string("hi\\i")
+      end
+
+      def test_quoted_date
+        t = Date.today
+        assert_equal t.to_s(:db), @quoter.quoted_date(t)
+      end
+
+      def test_quoted_time_utc
+        with_timezone_config default: :utc do
+          t = Time.now
+          assert_equal t.getutc.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      def test_quoted_time_local
+        with_timezone_config default: :local do
+          t = Time.now
+          assert_equal t.getlocal.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      def test_quoted_time_crazy
+        with_timezone_config default: :asdfasdf do
+          t = Time.now
+          assert_equal t.getlocal.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      def test_quoted_datetime_utc
+        with_timezone_config default: :utc do
+          t = DateTime.now
+          assert_equal t.getutc.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      ###
+      # DateTime doesn't define getlocal, so make sure it does nothing
+      def test_quoted_datetime_local
+        with_timezone_config default: :local do
+          t = DateTime.now
+          assert_equal t.to_s(:db), @quoter.quoted_date(t)
+        end
+      end
+
+      def test_quote_with_quoted_id
+        assert_equal 1, @quoter.quote(Struct.new(:quoted_id).new(1), nil)
+      end
+
+      def test_quote_nil
+        assert_equal 'NULL', @quoter.quote(nil, nil)
+      end
+
+      def test_quote_true
+        assert_equal @quoter.quoted_true, @quoter.quote(true, nil)
+      end
+
+      def test_quote_false
+        assert_equal @quoter.quoted_false, @quoter.quote(false, nil)
+      end
+
+      def test_quote_float
+        float = 1.2
+        assert_equal float.to_s, @quoter.quote(float, nil)
+      end
+
+      def test_quote_fixnum
+        fixnum = 1
+        assert_equal fixnum.to_s, @quoter.quote(fixnum, nil)
+      end
+
+      def test_quote_bignum
+        bignum = 1 << 100
+        assert_equal bignum.to_s, @quoter.quote(bignum, nil)
+      end
+
+      def test_quote_bigdecimal
+        bigdec = BigDecimal.new((1 << 100).to_s)
+        assert_equal bigdec.to_s('F'), @quoter.quote(bigdec, nil)
+      end
+
+      def test_dates_and_times
+        @quoter.extend(Module.new { def quoted_date(value) 'lol' end })
+        assert_equal "'lol'", @quoter.quote(Date.today, nil)
+        assert_equal "'lol'", @quoter.quote(Time.now, nil)
+        assert_equal "'lol'", @quoter.quote(DateTime.now, nil)
+      end
+
+      def test_crazy_object
+        crazy = Class.new.new
+        expected = "'#{YAML.dump(crazy)}'"
+        assert_equal expected, @quoter.quote(crazy, nil)
+      end
+
+      def test_crazy_object_calls_quote_string
+        crazy = Class.new { def initialize; @lol = 'lo\l' end }.new
+        assert_match "lo\\\\l", @quoter.quote(crazy, nil)
+      end
+
+      def test_quote_string_no_column
+        assert_equal "'lo\\\\l'", @quoter.quote('lo\l', nil)
+      end
+
+      def test_quote_as_mb_chars_no_column
+        string = ActiveSupport::Multibyte::Chars.new('lo\l')
+        assert_equal "'lo\\\\l'", @quoter.quote(string, nil)
+      end
+
+      def test_string_with_crazy_column
+        assert_equal "'lo\\\\l'", @quoter.quote('lo\l')
+      end
+
+      def test_quote_duration
+        assert_equal "1800", @quoter.quote(30.minutes)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/readonly_test.rb b/activerecord/test/cases/readonly_test.rb
new file mode 100644
index 0000000000..2afd25c989
--- /dev/null
+++ b/activerecord/test/cases/readonly_test.rb
@@ -0,0 +1,111 @@
+require "cases/helper"
+require 'models/author'
+require 'models/post'
+require 'models/comment'
+require 'models/developer'
+require 'models/project'
+require 'models/reader'
+require 'models/person'
+
+class ReadOnlyTest < ActiveRecord::TestCase
+  fixtures :authors, :posts, :comments, :developers, :projects, :developers_projects, :people, :readers
+
+  def test_cant_save_readonly_record
+    dev = Developer.find(1)
+    assert !dev.readonly?
+
+    dev.readonly!
+    assert dev.readonly?
+
+    assert_nothing_raised do
+      dev.name = 'Luscious forbidden fruit.'
+      assert !dev.save
+      dev.name = 'Forbidden.'
+    end
+    assert_raise(ActiveRecord::ReadOnlyRecord) { dev.save  }
+    assert_raise(ActiveRecord::ReadOnlyRecord) { dev.save! }
+    assert_raise(ActiveRecord::ReadOnlyRecord) { dev.destroy }
+  end
+
+
+  def test_find_with_readonly_option
+    Developer.all.each { |d| assert !d.readonly? }
+    Developer.readonly(false).each { |d| assert !d.readonly? }
+    Developer.readonly(true).each { |d| assert d.readonly? }
+    Developer.readonly.each { |d| assert d.readonly? }
+  end
+
+  def test_find_with_joins_option_does_not_imply_readonly
+    Developer.joins('  ').each { |d| assert_not d.readonly? }
+    Developer.joins('  ').readonly(true).each { |d| assert d.readonly? }
+
+    Developer.joins(', projects').each { |d| assert_not d.readonly? }
+    Developer.joins(', projects').readonly(true).each { |d| assert d.readonly? }
+  end
+
+  def test_has_many_find_readonly
+    post = Post.find(1)
+    assert !post.comments.empty?
+    assert !post.comments.any?(&:readonly?)
+    assert !post.comments.to_a.any?(&:readonly?)
+    assert post.comments.readonly(true).all?(&:readonly?)
+  end
+
+  def test_has_many_with_through_is_not_implicitly_marked_readonly
+    assert people = Post.find(1).people
+    assert !people.any?(&:readonly?)
+  end
+
+  def test_has_many_with_through_is_not_implicitly_marked_readonly_while_finding_by_id
+    assert !posts(:welcome).people.find(1).readonly?
+  end
+
+  def test_has_many_with_through_is_not_implicitly_marked_readonly_while_finding_first
+    assert !posts(:welcome).people.first.readonly?
+  end
+
+  def test_has_many_with_through_is_not_implicitly_marked_readonly_while_finding_last
+    assert !posts(:welcome).people.last.readonly?
+  end
+
+  def test_readonly_scoping
+    Post.where('1=1').scoping do
+      assert !Post.find(1).readonly?
+      assert Post.readonly(true).find(1).readonly?
+      assert !Post.readonly(false).find(1).readonly?
+    end
+
+    Post.joins('   ').scoping do
+      assert !Post.find(1).readonly?
+      assert Post.readonly.find(1).readonly?
+      assert !Post.readonly(false).find(1).readonly?
+    end
+
+    # Oracle barfs on this because the join includes unqualified and
+    # conflicting column names
+    unless current_adapter?(:OracleAdapter)
+      Post.joins(', developers').scoping do
+        assert_not Post.find(1).readonly?
+        assert Post.readonly.find(1).readonly?
+        assert !Post.readonly(false).find(1).readonly?
+      end
+    end
+
+    Post.readonly(true).scoping do
+      assert Post.find(1).readonly?
+      assert Post.readonly.find(1).readonly?
+      assert !Post.readonly(false).find(1).readonly?
+    end
+  end
+
+  def test_association_collection_method_missing_scoping_not_readonly
+    developer = Developer.find(1)
+    project   = Post.find(1)
+
+    assert !developer.projects.all_as_method.first.readonly?
+    assert !developer.projects.all_as_scope.first.readonly?
+
+    assert !project.comments.all_as_method.first.readonly?
+    assert !project.comments.all_as_scope.first.readonly?
+  end
+end
diff --git a/activerecord/test/cases/reaper_test.rb b/activerecord/test/cases/reaper_test.rb
new file mode 100644
index 0000000000..f52fd22489
--- /dev/null
+++ b/activerecord/test/cases/reaper_test.rb
@@ -0,0 +1,85 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ReaperTest < ActiveRecord::TestCase
+      attr_reader :pool
+
+      def setup
+        super
+        @pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+      end
+
+      teardown do
+        @pool.connections.each(&:close)
+      end
+
+      class FakePool
+        attr_reader :reaped
+
+        def initialize
+          @reaped = false
+        end
+
+        def reap
+          @reaped = true
+        end
+      end
+
+      # A reaper with nil time should never reap connections
+      def test_nil_time
+        fp = FakePool.new
+        assert !fp.reaped
+        reaper = ConnectionPool::Reaper.new(fp, nil)
+        reaper.run
+        assert !fp.reaped
+      end
+
+      def test_some_time
+        fp = FakePool.new
+        assert !fp.reaped
+
+        reaper = ConnectionPool::Reaper.new(fp, 0.0001)
+        reaper.run
+        until fp.reaped
+          Thread.pass
+        end
+        assert fp.reaped
+      end
+
+      def test_pool_has_reaper
+        assert pool.reaper
+      end
+
+      def test_reaping_frequency_configuration
+        spec = ActiveRecord::Base.connection_pool.spec.dup
+        spec.config[:reaping_frequency] = 100
+        pool = ConnectionPool.new spec
+        assert_equal 100, pool.reaper.frequency
+      end
+
+      def test_connection_pool_starts_reaper
+        spec = ActiveRecord::Base.connection_pool.spec.dup
+        spec.config[:reaping_frequency] = 0.0001
+
+        pool = ConnectionPool.new spec
+
+        conn = nil
+        child = Thread.new do
+          conn = pool.checkout
+          Thread.stop
+        end
+        Thread.pass while conn.nil?
+
+        assert conn.in_use?
+
+        child.terminate
+
+        while conn.in_use?
+          Thread.pass
+        end
+        assert !conn.in_use?
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/reflection_test.rb b/activerecord/test/cases/reflection_test.rb
new file mode 100644
index 0000000000..84abaf0291
--- /dev/null
+++ b/activerecord/test/cases/reflection_test.rb
@@ -0,0 +1,450 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/customer'
+require 'models/company'
+require 'models/company_in_module'
+require 'models/ship'
+require 'models/pirate'
+require 'models/price_estimate'
+require 'models/essay'
+require 'models/author'
+require 'models/organization'
+require 'models/post'
+require 'models/tagging'
+require 'models/category'
+require 'models/book'
+require 'models/subscriber'
+require 'models/subscription'
+require 'models/tag'
+require 'models/sponsor'
+require 'models/edge'
+require 'models/hotel'
+require 'models/chef'
+require 'models/department'
+require 'models/cake_designer'
+require 'models/drink_designer'
+
+class ReflectionTest < ActiveRecord::TestCase
+  include ActiveRecord::Reflection
+
+  fixtures :topics, :customers, :companies, :subscribers, :price_estimates
+
+  def setup
+    @first = Topic.find(1)
+  end
+
+  def test_human_name
+    assert_equal "Price estimate", PriceEstimate.model_name.human
+    assert_equal "Subscriber", Subscriber.model_name.human
+  end
+
+  def test_read_attribute_names
+    assert_equal(
+      %w( id title author_name author_email_address bonus_time written_on last_read content important group approved replies_count unique_replies_count parent_id parent_title type created_at updated_at ).sort,
+      @first.attribute_names.sort
+    )
+  end
+
+  def test_columns
+    assert_equal 18, Topic.columns.length
+  end
+
+  def test_columns_are_returned_in_the_order_they_were_declared
+    column_names = Topic.columns.map { |column| column.name }
+    assert_equal %w(id title author_name author_email_address written_on bonus_time last_read content important approved replies_count unique_replies_count parent_id parent_title type group created_at updated_at), column_names
+  end
+
+  def test_content_columns
+    content_columns        = Topic.content_columns
+    content_column_names   = content_columns.map {|column| column.name}
+    assert_equal 13, content_columns.length
+    assert_equal %w(title author_name author_email_address written_on bonus_time last_read content important group approved parent_title created_at updated_at).sort, content_column_names.sort
+  end
+
+  def test_column_string_type_and_limit
+    assert_equal :string, @first.column_for_attribute("title").type
+    assert_equal 250, @first.column_for_attribute("title").limit
+  end
+
+  def test_column_null_not_null
+    subscriber = Subscriber.first
+    assert subscriber.column_for_attribute("name").null
+    assert !subscriber.column_for_attribute("nick").null
+  end
+
+  def test_human_name_for_column
+    assert_equal "Author name", @first.column_for_attribute("author_name").human_name
+  end
+
+  def test_integer_columns
+    assert_equal :integer, @first.column_for_attribute("id").type
+  end
+
+  def test_non_existent_columns_return_nil
+    assert_deprecated do
+      assert_nil @first.column_for_attribute("attribute_that_doesnt_exist")
+    end
+  end
+
+  def test_reflection_klass_for_nested_class_name
+    reflection = ActiveRecord::Reflection.create(:has_many, nil, nil, { :class_name => 'MyApplication::Business::Company' }, ActiveRecord::Base)
+    assert_nothing_raised do
+      assert_equal MyApplication::Business::Company, reflection.klass
+    end
+  end
+
+  def test_irregular_reflection_class_name
+    ActiveSupport::Inflector.inflections do |inflect|
+      inflect.irregular 'plural_irregular', 'plurales_irregulares'
+    end
+    reflection = ActiveRecord::Reflection.create(:has_many, 'plurales_irregulares', nil, {}, ActiveRecord::Base)
+    assert_equal 'PluralIrregular', reflection.class_name
+  end
+
+  def test_aggregation_reflection
+    reflection_for_address = AggregateReflection.new(
+      :address, nil, { :mapping => [ %w(address_street street), %w(address_city city), %w(address_country country) ] }, Customer
+    )
+
+    reflection_for_balance = AggregateReflection.new(
+      :balance, nil, { :class_name => "Money", :mapping => %w(balance amount) }, Customer
+    )
+
+    reflection_for_gps_location = AggregateReflection.new(
+      :gps_location, nil, { }, Customer
+    )
+
+    assert Customer.reflect_on_all_aggregations.include?(reflection_for_gps_location)
+    assert Customer.reflect_on_all_aggregations.include?(reflection_for_balance)
+    assert Customer.reflect_on_all_aggregations.include?(reflection_for_address)
+
+    assert_equal reflection_for_address, Customer.reflect_on_aggregation(:address)
+
+    assert_equal Address, Customer.reflect_on_aggregation(:address).klass
+
+    assert_equal Money, Customer.reflect_on_aggregation(:balance).klass
+  end
+
+  def test_reflect_on_all_autosave_associations
+    expected = Pirate.reflect_on_all_associations.select { |r| r.options[:autosave] }
+    received = Pirate.reflect_on_all_autosave_associations
+
+    assert !received.empty?
+    assert_not_equal Pirate.reflect_on_all_associations.length, received.length
+    assert_equal expected, received
+  end
+
+  def test_has_many_reflection
+    reflection_for_clients = ActiveRecord::Reflection.create(:has_many, :clients, nil, { :order => "id", :dependent => :destroy }, Firm)
+
+    assert_equal reflection_for_clients, Firm.reflect_on_association(:clients)
+
+    assert_equal Client, Firm.reflect_on_association(:clients).klass
+    assert_equal 'companies', Firm.reflect_on_association(:clients).table_name
+
+    assert_equal Client, Firm.reflect_on_association(:clients_of_firm).klass
+    assert_equal 'companies', Firm.reflect_on_association(:clients_of_firm).table_name
+  end
+
+  def test_has_one_reflection
+    reflection_for_account = ActiveRecord::Reflection.create(:has_one, :account, nil, { :foreign_key => "firm_id", :dependent => :destroy }, Firm)
+    assert_equal reflection_for_account, Firm.reflect_on_association(:account)
+
+    assert_equal Account, Firm.reflect_on_association(:account).klass
+    assert_equal 'accounts', Firm.reflect_on_association(:account).table_name
+  end
+
+  def test_belongs_to_inferred_foreign_key_from_assoc_name
+    Company.belongs_to :foo
+    assert_equal "foo_id", Company.reflect_on_association(:foo).foreign_key
+    Company.belongs_to :bar, :class_name => "Xyzzy"
+    assert_equal "bar_id", Company.reflect_on_association(:bar).foreign_key
+    Company.belongs_to :baz, :class_name => "Xyzzy", :foreign_key => "xyzzy_id"
+    assert_equal "xyzzy_id", Company.reflect_on_association(:baz).foreign_key
+  end
+
+  def test_association_reflection_in_modules
+    ActiveRecord::Base.store_full_sti_class = false
+
+    assert_reflection MyApplication::Business::Firm,
+      :clients_of_firm,
+      :klass      => MyApplication::Business::Client,
+      :class_name => 'Client',
+      :table_name => 'companies'
+
+    assert_reflection MyApplication::Billing::Account,
+      :firm,
+      :klass      => MyApplication::Business::Firm,
+      :class_name => 'MyApplication::Business::Firm',
+      :table_name => 'companies'
+
+    assert_reflection MyApplication::Billing::Account,
+      :qualified_billing_firm,
+      :klass      => MyApplication::Billing::Firm,
+      :class_name => 'MyApplication::Billing::Firm',
+      :table_name => 'companies'
+
+    assert_reflection MyApplication::Billing::Account,
+      :unqualified_billing_firm,
+      :klass      => MyApplication::Billing::Firm,
+      :class_name => 'Firm',
+      :table_name => 'companies'
+
+    assert_reflection MyApplication::Billing::Account,
+      :nested_qualified_billing_firm,
+      :klass      => MyApplication::Billing::Nested::Firm,
+      :class_name => 'MyApplication::Billing::Nested::Firm',
+      :table_name => 'companies'
+
+    assert_reflection MyApplication::Billing::Account,
+      :nested_unqualified_billing_firm,
+      :klass      => MyApplication::Billing::Nested::Firm,
+      :class_name => 'Nested::Firm',
+      :table_name => 'companies'
+  ensure
+    ActiveRecord::Base.store_full_sti_class = true
+  end
+
+  def test_reflection_should_not_raise_error_when_compared_to_other_object
+    assert_not_equal Object.new, Firm._reflections['clients']
+  end
+
+  def test_has_and_belongs_to_many_reflection
+    assert_equal :has_and_belongs_to_many, Category.reflections['posts'].macro
+    assert_equal :posts, Category.reflect_on_all_associations(:has_and_belongs_to_many).first.name
+  end
+
+  def test_has_many_through_reflection
+    assert_kind_of ThroughReflection, Subscriber.reflect_on_association(:books)
+  end
+
+  def test_chain
+    expected = [
+      Organization.reflect_on_association(:author_essay_categories),
+      Author.reflect_on_association(:essays),
+      Organization.reflect_on_association(:authors)
+    ]
+    actual = Organization.reflect_on_association(:author_essay_categories).chain
+
+    assert_equal expected, actual
+  end
+
+  def test_scope_chain
+    expected = [
+      [Tagging.reflect_on_association(:tag).scope, Post.reflect_on_association(:first_blue_tags).scope],
+      [Post.reflect_on_association(:first_taggings).scope],
+      [Author.reflect_on_association(:misc_posts).scope]
+    ]
+    actual = Author.reflect_on_association(:misc_post_first_blue_tags).scope_chain
+    assert_equal expected, actual
+
+    expected = [
+      [
+        Tagging.reflect_on_association(:blue_tag).scope,
+        Post.reflect_on_association(:first_blue_tags_2).scope,
+        Author.reflect_on_association(:misc_post_first_blue_tags_2).scope
+      ],
+      [],
+      []
+    ]
+    actual = Author.reflect_on_association(:misc_post_first_blue_tags_2).scope_chain
+    assert_equal expected, actual
+  end
+
+  def test_scope_chain_does_not_interfere_with_hmt_with_polymorphic_case
+    @hotel = Hotel.create!
+    @department = @hotel.departments.create!
+    @department.chefs.create!(employable: CakeDesigner.create!)
+    @department.chefs.create!(employable: DrinkDesigner.create!)
+
+    assert_equal 1, @hotel.cake_designers.size
+    assert_equal 1, @hotel.drink_designers.size
+    assert_equal 2, @hotel.chefs.size
+  end
+
+  def test_nested?
+    assert !Author.reflect_on_association(:comments).nested?
+    assert Author.reflect_on_association(:tags).nested?
+
+    # Only goes :through once, but the through_reflection is a has_and_belongs_to_many, so this is
+    # a nested through association
+    assert Category.reflect_on_association(:post_comments).nested?
+  end
+
+  def test_association_primary_key
+    # Normal association
+    assert_equal "id",   Author.reflect_on_association(:posts).association_primary_key.to_s
+    assert_equal "name", Author.reflect_on_association(:essay).association_primary_key.to_s
+    assert_equal "name", Essay.reflect_on_association(:writer).association_primary_key.to_s
+
+    # Through association (uses the :primary_key option from the source reflection)
+    assert_equal "nick", Author.reflect_on_association(:subscribers).association_primary_key.to_s
+    assert_equal "name", Author.reflect_on_association(:essay_category).association_primary_key.to_s
+    assert_equal "custom_primary_key", Author.reflect_on_association(:tags_with_primary_key).association_primary_key.to_s # nested
+  end
+
+  def test_association_primary_key_raises_when_missing_primary_key
+    reflection = ActiveRecord::Reflection.create(:has_many, :edge, nil, {}, Author)
+    assert_raises(ActiveRecord::UnknownPrimaryKey) { reflection.association_primary_key }
+
+    through = Class.new(ActiveRecord::Reflection::ThroughReflection) {
+      define_method(:source_reflection) { reflection }
+    }.new(reflection)
+    assert_raises(ActiveRecord::UnknownPrimaryKey) { through.association_primary_key }
+  end
+
+  def test_active_record_primary_key
+    assert_equal "nick", Subscriber.reflect_on_association(:subscriptions).active_record_primary_key.to_s
+    assert_equal "name", Author.reflect_on_association(:essay).active_record_primary_key.to_s
+  end
+
+  def test_active_record_primary_key_raises_when_missing_primary_key
+    reflection = ActiveRecord::Reflection.create(:has_many, :author, nil, {}, Edge)
+    assert_raises(ActiveRecord::UnknownPrimaryKey) { reflection.active_record_primary_key }
+  end
+
+  def test_foreign_type
+    assert_equal "sponsorable_type", Sponsor.reflect_on_association(:sponsorable).foreign_type.to_s
+    assert_equal "sponsorable_type", Sponsor.reflect_on_association(:thing).foreign_type.to_s
+  end
+
+  def test_collection_association
+    assert Pirate.reflect_on_association(:birds).collection?
+    assert Pirate.reflect_on_association(:parrots).collection?
+
+    assert !Pirate.reflect_on_association(:ship).collection?
+    assert !Ship.reflect_on_association(:pirate).collection?
+  end
+
+  def test_default_association_validation
+    assert ActiveRecord::Reflection.create(:has_many, :clients, nil, {}, Firm).validate?
+
+    assert !ActiveRecord::Reflection.create(:has_one, :client, nil, {}, Firm).validate?
+    assert !ActiveRecord::Reflection.create(:belongs_to, :client, nil, {}, Firm).validate?
+  end
+
+  def test_always_validate_association_if_explicit
+    assert ActiveRecord::Reflection.create(:has_one, :client, nil, { :validate => true }, Firm).validate?
+    assert ActiveRecord::Reflection.create(:belongs_to, :client, nil, { :validate => true }, Firm).validate?
+    assert ActiveRecord::Reflection.create(:has_many, :clients, nil, { :validate => true }, Firm).validate?
+  end
+
+  def test_validate_association_if_autosave
+    assert ActiveRecord::Reflection.create(:has_one, :client, nil, { :autosave => true }, Firm).validate?
+    assert ActiveRecord::Reflection.create(:belongs_to, :client, nil, { :autosave => true }, Firm).validate?
+    assert ActiveRecord::Reflection.create(:has_many, :clients, nil, { :autosave => true }, Firm).validate?
+  end
+
+  def test_never_validate_association_if_explicit
+    assert !ActiveRecord::Reflection.create(:has_one, :client, nil, { :autosave => true, :validate => false }, Firm).validate?
+    assert !ActiveRecord::Reflection.create(:belongs_to, :client, nil, { :autosave => true, :validate => false }, Firm).validate?
+    assert !ActiveRecord::Reflection.create(:has_many, :clients, nil, { :autosave => true, :validate => false }, Firm).validate?
+  end
+
+  def test_foreign_key
+    assert_equal "author_id", Author.reflect_on_association(:posts).foreign_key.to_s
+    assert_equal "category_id", Post.reflect_on_association(:categorizations).foreign_key.to_s
+  end
+
+  def test_through_reflection_scope_chain_does_not_modify_other_reflections
+    orig_conds = Post.reflect_on_association(:first_blue_tags_2).scope_chain.inspect
+    Author.reflect_on_association(:misc_post_first_blue_tags_2).scope_chain
+    assert_equal orig_conds, Post.reflect_on_association(:first_blue_tags_2).scope_chain.inspect
+  end
+
+  def test_symbol_for_class_name
+    assert_equal Client, Firm.reflect_on_association(:unsorted_clients_with_symbol).klass
+  end
+
+  def test_join_table
+    category = Struct.new(:table_name, :pluralize_table_names).new('categories', true)
+    product = Struct.new(:table_name, :pluralize_table_names).new('products', true)
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :categories, nil, {}, product)
+    reflection.stubs(:klass).returns(category)
+    assert_equal 'categories_products', reflection.join_table
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :products, nil, {}, category)
+    reflection.stubs(:klass).returns(product)
+    assert_equal 'categories_products', reflection.join_table
+  end
+
+  def test_join_table_with_common_prefix
+    category = Struct.new(:table_name, :pluralize_table_names).new('catalog_categories', true)
+    product = Struct.new(:table_name, :pluralize_table_names).new('catalog_products', true)
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :categories, nil, {}, product)
+    reflection.stubs(:klass).returns(category)
+    assert_equal 'catalog_categories_products', reflection.join_table
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :products, nil, {}, category)
+    reflection.stubs(:klass).returns(product)
+    assert_equal 'catalog_categories_products', reflection.join_table
+  end
+
+  def test_join_table_with_different_prefix
+    category = Struct.new(:table_name, :pluralize_table_names).new('catalog_categories', true)
+    page = Struct.new(:table_name, :pluralize_table_names).new('content_pages', true)
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :categories, nil, {}, page)
+    reflection.stubs(:klass).returns(category)
+    assert_equal 'catalog_categories_content_pages', reflection.join_table
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :pages, nil, {}, category)
+    reflection.stubs(:klass).returns(page)
+    assert_equal 'catalog_categories_content_pages', reflection.join_table
+  end
+
+  def test_join_table_can_be_overridden
+    category = Struct.new(:table_name, :pluralize_table_names).new('categories', true)
+    product = Struct.new(:table_name, :pluralize_table_names).new('products', true)
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :categories, nil, { :join_table => 'product_categories' }, product)
+    reflection.stubs(:klass).returns(category)
+    assert_equal 'product_categories', reflection.join_table
+
+    reflection = ActiveRecord::Reflection.create(:has_many, :products, nil, { :join_table => 'product_categories' }, category)
+    reflection.stubs(:klass).returns(product)
+    assert_equal 'product_categories', reflection.join_table
+  end
+
+  def test_includes_accepts_symbols
+    hotel = Hotel.create!
+    department = hotel.departments.create!
+    department.chefs.create!
+
+    assert_nothing_raised do
+      assert_equal department.chefs, Hotel.includes([departments: :chefs]).first.chefs
+    end
+  end
+
+  def test_includes_accepts_strings
+    hotel = Hotel.create!
+    department = hotel.departments.create!
+    department.chefs.create!
+
+    assert_nothing_raised do
+      assert_equal department.chefs, Hotel.includes(['departments' => 'chefs']).first.chefs
+    end
+  end
+
+  def test_reflect_on_association_accepts_symbols
+    assert_nothing_raised do
+      assert_equal Hotel.reflect_on_association(:departments).name, :departments
+    end
+  end
+
+  def test_reflect_on_association_accepts_strings
+    assert_nothing_raised do
+      assert_equal Hotel.reflect_on_association("departments").name, :departments
+    end
+  end
+
+  private
+    def assert_reflection(klass, association, options)
+      assert reflection = klass.reflect_on_association(association)
+      options.each do |method, value|
+        assert_equal(value, reflection.send(method))
+      end
+    end
+end
diff --git a/activerecord/test/cases/relation/delegation_test.rb b/activerecord/test/cases/relation/delegation_test.rb
new file mode 100644
index 0000000000..29c9d0e2af
--- /dev/null
+++ b/activerecord/test/cases/relation/delegation_test.rb
@@ -0,0 +1,68 @@
+require 'cases/helper'
+require 'models/post'
+require 'models/comment'
+
+module ActiveRecord
+  class DelegationTest < ActiveRecord::TestCase
+    fixtures :posts
+
+    def call_method(target, method)
+      method_arity = target.to_a.method(method).arity
+
+      if method_arity.zero?
+        target.public_send(method)
+      elsif method_arity < 0
+        if method == :shuffle!
+          target.public_send(method)
+        else
+          target.public_send(method, 1)
+        end
+       elsif method_arity == 1
+        target.public_send(method, 1)
+      else
+        raise NotImplementedError
+      end
+    end
+  end
+
+  module DelegationWhitelistBlacklistTests
+    ARRAY_DELEGATES = [
+      :+, :-, :|, :&, :[],
+      :all?, :collect, :detect, :each, :each_cons, :each_with_index,
+      :exclude?, :find_all, :flat_map, :group_by, :include?, :length,
+      :map, :none?, :one?, :partition, :reject, :reverse,
+      :sample, :second, :sort, :sort_by, :third,
+      :to_ary, :to_set, :to_xml, :to_yaml, :join
+    ]
+
+    ARRAY_DELEGATES.each do |method|
+      define_method "test_delegates_#{method}_to_Array" do
+        assert_respond_to target, method
+      end
+    end
+
+    ActiveRecord::Delegation::BLACKLISTED_ARRAY_METHODS.each do |method|
+      define_method "test_#{method}_is_not_delegated_to_Array" do
+        assert_raises(NoMethodError) { call_method(target, method) }
+      end
+    end
+  end
+
+  class DelegationAssociationTest < DelegationTest
+    include DelegationWhitelistBlacklistTests
+
+    def target
+      Post.first.comments
+    end
+  end
+
+  class DelegationRelationTest < DelegationTest
+    include DelegationWhitelistBlacklistTests
+
+    fixtures :comments
+
+    def target
+      Comment.all
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/merging_test.rb b/activerecord/test/cases/relation/merging_test.rb
new file mode 100644
index 0000000000..2b5c2fd5a4
--- /dev/null
+++ b/activerecord/test/cases/relation/merging_test.rb
@@ -0,0 +1,147 @@
+require 'cases/helper'
+require 'models/author'
+require 'models/comment'
+require 'models/developer'
+require 'models/post'
+require 'models/project'
+
+class RelationMergingTest < ActiveRecord::TestCase
+  fixtures :developers, :comments, :authors, :posts
+
+  def test_relation_merging
+    devs = Developer.where("salary >= 80000").merge(Developer.limit(2)).merge(Developer.order('id ASC').where("id < 3"))
+    assert_equal [developers(:david), developers(:jamis)], devs.to_a
+
+    dev_with_count = Developer.limit(1).merge(Developer.order('id DESC')).merge(Developer.select('developers.*'))
+    assert_equal [developers(:poor_jamis)], dev_with_count.to_a
+  end
+
+  def test_relation_to_sql
+    post = Post.first
+    sql = post.comments.to_sql
+    assert_match(/.?post_id.? = #{post.id}\Z/i, sql)
+  end
+
+  def test_relation_merging_with_arel_equalities_keeps_last_equality
+    devs = Developer.where(Developer.arel_table[:salary].eq(80000)).merge(
+      Developer.where(Developer.arel_table[:salary].eq(9000))
+    )
+    assert_equal [developers(:poor_jamis)], devs.to_a
+  end
+
+  def test_relation_merging_with_arel_equalities_keeps_last_equality_with_non_attribute_left_hand
+    salary_attr = Developer.arel_table[:salary]
+    devs = Developer.where(
+      Arel::Nodes::NamedFunction.new('abs', [salary_attr]).eq(80000)
+    ).merge(
+      Developer.where(
+        Arel::Nodes::NamedFunction.new('abs', [salary_attr]).eq(9000)
+      )
+    )
+    assert_equal [developers(:poor_jamis)], devs.to_a
+  end
+
+  def test_relation_merging_with_eager_load
+    relations = []
+    relations << Post.order('comments.id DESC').merge(Post.eager_load(:last_comment)).merge(Post.all)
+    relations << Post.eager_load(:last_comment).merge(Post.order('comments.id DESC')).merge(Post.all)
+
+    relations.each do |posts|
+      post = posts.find { |p| p.id == 1 }
+      assert_equal Post.find(1).last_comment, post.last_comment
+    end
+  end
+
+  def test_relation_merging_with_locks
+    devs = Developer.lock.where("salary >= 80000").order("id DESC").merge(Developer.limit(2))
+    assert devs.locked.present?
+  end
+
+  def test_relation_merging_with_preload
+    [Post.all.merge(Post.preload(:author)), Post.preload(:author).merge(Post.all)].each do |posts|
+      assert_queries(2) { assert posts.first.author }
+    end
+  end
+
+  def test_relation_merging_with_joins
+    comments = Comment.joins(:post).where(:body => 'Thank you for the welcome').merge(Post.where(:body => 'Such a lovely day'))
+    assert_equal 1, comments.count
+  end
+
+  def test_relation_merging_with_association
+    assert_queries(2) do  # one for loading post, and another one merged query
+      post = Post.where(:body => 'Such a lovely day').first
+      comments = Comment.where(:body => 'Thank you for the welcome').merge(post.comments)
+      assert_equal 1, comments.count
+    end
+  end
+
+  test "merge collapses wheres from the LHS only" do
+    left  = Post.where(title: "omg").where(comments_count: 1)
+    right = Post.where(title: "wtf").where(title: "bbq")
+
+    expected = [left.bind_values[1]] + right.bind_values
+    merged   = left.merge(right)
+
+    assert_equal expected, merged.bind_values
+    assert !merged.to_sql.include?("omg")
+    assert merged.to_sql.include?("wtf")
+    assert merged.to_sql.include?("bbq")
+  end
+
+  def test_merging_keeps_lhs_bind_parameters
+    column = Post.columns_hash['id']
+    binds = [[column, 20]]
+
+    right  = Post.where(id: 20)
+    left   = Post.where(id: 10)
+
+    merged = left.merge(right)
+    assert_equal binds, merged.bind_values
+  end
+
+  def test_merging_reorders_bind_params
+    post  = Post.first
+    right = Post.where(id: 1)
+    left  = Post.where(title: post.title)
+
+    merged = left.merge(right)
+    assert_equal post, merged.first
+  end
+
+  def test_merging_compares_symbols_and_strings_as_equal
+    post = PostThatLoadsCommentsInAnAfterSaveHook.create!(title: "First Post", body: "Blah blah blah.")
+    assert_equal "First comment!", post.comments.where(body: "First comment!").first_or_create.body
+  end
+end
+
+class MergingDifferentRelationsTest < ActiveRecord::TestCase
+  fixtures :posts, :authors
+
+  test "merging where relations" do
+    hello_by_bob = Post.where(body: "hello").joins(:author).
+      merge(Author.where(name: "Bob")).order("posts.id").pluck("posts.id")
+
+    assert_equal [posts(:misc_by_bob).id,
+                  posts(:other_by_bob).id], hello_by_bob
+  end
+
+  test "merging order relations" do
+    posts_by_author_name = Post.limit(3).joins(:author).
+      merge(Author.order(:name)).pluck("authors.name")
+
+    assert_equal ["Bob", "Bob", "David"], posts_by_author_name
+
+    posts_by_author_name = Post.limit(3).joins(:author).
+      merge(Author.order("name")).pluck("authors.name")
+
+    assert_equal ["Bob", "Bob", "David"], posts_by_author_name
+  end
+
+  test "merging order relations (using a hash argument)" do
+    posts_by_author_name = Post.limit(4).joins(:author).
+      merge(Author.order(name: :desc)).pluck("authors.name")
+
+    assert_equal ["Mary", "Mary", "Mary", "David"], posts_by_author_name
+  end
+end
diff --git a/activerecord/test/cases/relation/mutation_test.rb b/activerecord/test/cases/relation/mutation_test.rb
new file mode 100644
index 0000000000..1da5c36e1c
--- /dev/null
+++ b/activerecord/test/cases/relation/mutation_test.rb
@@ -0,0 +1,161 @@
+require 'cases/helper'
+require 'models/post'
+
+module ActiveRecord
+  class RelationMutationTest < ActiveSupport::TestCase
+    class FakeKlass < Struct.new(:table_name, :name)
+      extend ActiveRecord::Delegation::DelegateCache
+      inherited self
+
+      def connection
+        Post.connection
+      end
+
+      def relation_delegate_class(klass)
+        self.class.relation_delegate_class(klass)
+      end
+
+      def attribute_alias?(name)
+        false
+      end
+    end
+
+    def relation
+      @relation ||= Relation.new FakeKlass.new('posts'), Post.arel_table
+    end
+
+    (Relation::MULTI_VALUE_METHODS - [:references, :extending, :order, :unscope, :select]).each do |method|
+      test "##{method}!" do
+        assert relation.public_send("#{method}!", :foo).equal?(relation)
+        assert_equal [:foo], relation.public_send("#{method}_values")
+      end
+    end
+
+    test "#_select!" do
+      assert relation.public_send("_select!", :foo).equal?(relation)
+      assert_equal [:foo], relation.public_send("select_values")
+    end
+
+    test '#order!' do
+      assert relation.order!('name ASC').equal?(relation)
+      assert_equal ['name ASC'], relation.order_values
+    end
+
+    test '#order! with symbol prepends the table name' do
+      assert relation.order!(:name).equal?(relation)
+      node = relation.order_values.first
+      assert node.ascending?
+      assert_equal :name, node.expr.name
+      assert_equal "posts", node.expr.relation.name
+    end
+
+    test '#order! on non-string does not attempt regexp match for references' do
+      obj = Object.new
+      obj.expects(:=~).never
+      assert relation.order!(obj)
+      assert_equal [obj], relation.order_values
+    end
+
+    test '#references!' do
+      assert relation.references!(:foo).equal?(relation)
+      assert relation.references_values.include?('foo')
+    end
+
+    test 'extending!' do
+      mod, mod2 = Module.new, Module.new
+
+      assert relation.extending!(mod).equal?(relation)
+      assert_equal [mod], relation.extending_values
+      assert relation.is_a?(mod)
+
+      relation.extending!(mod2)
+      assert_equal [mod, mod2], relation.extending_values
+    end
+
+    test 'extending! with empty args' do
+      relation.extending!
+      assert_equal [], relation.extending_values
+    end
+
+    (Relation::SINGLE_VALUE_METHODS - [:from, :lock, :reordering, :reverse_order, :create_with]).each do |method|
+      test "##{method}!" do
+        assert relation.public_send("#{method}!", :foo).equal?(relation)
+        assert_equal :foo, relation.public_send("#{method}_value")
+      end
+    end
+
+    test '#from!' do
+      assert relation.from!('foo').equal?(relation)
+      assert_equal ['foo', nil], relation.from_value
+    end
+
+    test '#lock!' do
+      assert relation.lock!('foo').equal?(relation)
+      assert_equal 'foo', relation.lock_value
+    end
+
+    test '#reorder!' do
+      relation = self.relation.order('foo')
+
+      assert relation.reorder!('bar').equal?(relation)
+      assert_equal ['bar'], relation.order_values
+      assert relation.reordering_value
+    end
+
+    test '#reorder! with symbol prepends the table name' do
+      assert relation.reorder!(:name).equal?(relation)
+      node = relation.order_values.first
+
+      assert node.ascending?
+      assert_equal :name, node.expr.name
+      assert_equal "posts", node.expr.relation.name
+    end
+
+    test 'reverse_order!' do
+      relation = Post.order('title ASC, comments_count DESC')
+
+      relation.reverse_order!
+
+      assert_equal 'title DESC', relation.order_values.first
+      assert_equal 'comments_count ASC', relation.order_values.last
+
+
+      relation.reverse_order!
+
+      assert_equal 'title ASC', relation.order_values.first
+      assert_equal 'comments_count DESC', relation.order_values.last
+    end
+
+    test 'create_with!' do
+      assert relation.create_with!(foo: 'bar').equal?(relation)
+      assert_equal({foo: 'bar'}, relation.create_with_value)
+    end
+
+    test 'test_merge!' do
+      assert relation.merge!(where: :foo).equal?(relation)
+      assert_equal [:foo], relation.where_values
+    end
+
+    test 'merge with a proc' do
+      assert_equal [:foo], relation.merge(-> { where(:foo) }).where_values
+    end
+
+    test 'none!' do
+      assert relation.none!.equal?(relation)
+      assert_equal [NullRelation], relation.extending_values
+      assert relation.is_a?(NullRelation)
+    end
+
+    test 'distinct!' do
+      relation.distinct! :foo
+      assert_equal :foo, relation.distinct_value
+      assert_equal :foo, relation.uniq_value # deprecated access
+    end
+
+    test 'uniq! was replaced by distinct!' do
+      relation.uniq! :foo
+      assert_equal :foo, relation.distinct_value
+      assert_equal :foo, relation.uniq_value # deprecated access
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/predicate_builder_test.rb b/activerecord/test/cases/relation/predicate_builder_test.rb
new file mode 100644
index 0000000000..4057835688
--- /dev/null
+++ b/activerecord/test/cases/relation/predicate_builder_test.rb
@@ -0,0 +1,14 @@
+require "cases/helper"
+require 'models/topic'
+
+module ActiveRecord
+  class PredicateBuilderTest < ActiveRecord::TestCase
+    def test_registering_new_handlers
+      PredicateBuilder.register_handler(Regexp, proc do |column, value|
+        Arel::Nodes::InfixOperation.new('~', column, Arel.sql(value.source))
+      end)
+
+      assert_match %r{["`]topics["`].["`]title["`] ~ rails}i, Topic.where(title: /rails/).to_sql
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/where_chain_test.rb b/activerecord/test/cases/relation/where_chain_test.rb
new file mode 100644
index 0000000000..b9e69bdb08
--- /dev/null
+++ b/activerecord/test/cases/relation/where_chain_test.rb
@@ -0,0 +1,153 @@
+require 'cases/helper'
+require 'models/post'
+require 'models/comment'
+
+module ActiveRecord
+  class WhereChainTest < ActiveRecord::TestCase
+    fixtures :posts
+
+    def setup
+      super
+      @name = 'title'
+    end
+
+    def test_not_eq
+      relation = Post.where.not(title: 'hello')
+
+      assert_equal 1, relation.where_values.length
+
+      value = relation.where_values.first
+      bind  = relation.bind_values.first
+
+      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::NotEqual
+      assert_equal 'hello', bind.last
+    end
+
+    def test_not_null
+      expected = Post.arel_table[@name].not_eq(nil)
+      relation = Post.where.not(title: nil)
+      assert_equal([expected], relation.where_values)
+    end
+
+    def test_not_with_nil
+      assert_raise ArgumentError do
+        Post.where.not(nil)
+      end
+    end
+
+    def test_not_in
+      expected = Post.arel_table[@name].not_in(%w[hello goodbye])
+      relation = Post.where.not(title: %w[hello goodbye])
+      assert_equal([expected], relation.where_values)
+    end
+
+    def test_association_not_eq
+      expected = Comment.arel_table[@name].not_eq('hello')
+      relation = Post.joins(:comments).where.not(comments: {title: 'hello'})
+      assert_equal(expected.to_sql, relation.where_values.first.to_sql)
+    end
+
+    def test_not_eq_with_preceding_where
+      relation = Post.where(title: 'hello').where.not(title: 'world')
+
+      value = relation.where_values.first
+      bind  = relation.bind_values.first
+      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::Equality
+      assert_equal 'hello', bind.last
+
+      value = relation.where_values.last
+      bind  = relation.bind_values.last
+      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::NotEqual
+      assert_equal 'world', bind.last
+    end
+
+    def test_not_eq_with_succeeding_where
+      relation = Post.where.not(title: 'hello').where(title: 'world')
+
+      value = relation.where_values.first
+      bind  = relation.bind_values.first
+      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::NotEqual
+      assert_equal 'hello', bind.last
+
+      value = relation.where_values.last
+      bind  = relation.bind_values.last
+      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::Equality
+      assert_equal 'world', bind.last
+    end
+
+    def test_not_eq_with_string_parameter
+      expected = Arel::Nodes::Not.new("title = 'hello'")
+      relation = Post.where.not("title = 'hello'")
+      assert_equal([expected], relation.where_values)
+    end
+
+    def test_not_eq_with_array_parameter
+      expected = Arel::Nodes::Not.new("title = 'hello'")
+      relation = Post.where.not(['title = ?', 'hello'])
+      assert_equal([expected], relation.where_values)
+    end
+
+    def test_chaining_multiple
+      relation = Post.where.not(author_id: [1, 2]).where.not(title: 'ruby on rails')
+
+      expected = Post.arel_table['author_id'].not_in([1, 2])
+      assert_equal(expected, relation.where_values[0])
+
+      value = relation.where_values[1]
+      bind  = relation.bind_values.first
+
+      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::NotEqual
+      assert_equal 'ruby on rails', bind.last
+    end
+
+    def test_rewhere_with_one_condition
+      relation = Post.where(title: 'hello').where(title: 'world').rewhere(title: 'alone')
+
+      assert_equal 1, relation.where_values.size
+      value = relation.where_values.first
+      bind = relation.bind_values.first
+      assert_bound_ast value, Post.arel_table[@name], Arel::Nodes::Equality
+      assert_equal 'alone', bind.last
+    end
+
+    def test_rewhere_with_multiple_overwriting_conditions
+      relation = Post.where(title: 'hello').where(body: 'world').rewhere(title: 'alone', body: 'again')
+
+      assert_equal 2, relation.where_values.size
+
+      value = relation.where_values.first
+      bind = relation.bind_values.first
+      assert_bound_ast value, Post.arel_table['title'], Arel::Nodes::Equality
+      assert_equal 'alone', bind.last
+
+      value = relation.where_values[1]
+      bind = relation.bind_values[1]
+      assert_bound_ast value, Post.arel_table['body'], Arel::Nodes::Equality
+      assert_equal 'again', bind.last
+    end
+
+    def assert_bound_ast value, table, type
+      assert_equal table, value.left
+      assert_kind_of type, value
+      assert_kind_of Arel::Nodes::BindParam, value.right
+    end
+
+    def test_rewhere_with_one_overwriting_condition_and_one_unrelated
+      relation = Post.where(title: 'hello').where(body: 'world').rewhere(title: 'alone')
+
+      assert_equal 2, relation.where_values.size
+
+      value = relation.where_values.first
+      bind  = relation.bind_values.first
+
+      assert_bound_ast value, Post.arel_table['body'], Arel::Nodes::Equality
+      assert_equal 'world', bind.last
+
+      value = relation.where_values.second
+      bind  = relation.bind_values.second
+
+      assert_bound_ast value, Post.arel_table['title'], Arel::Nodes::Equality
+      assert_equal 'alone', bind.last
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/where_test.rb b/activerecord/test/cases/relation/where_test.rb
new file mode 100644
index 0000000000..a6a36a6fd9
--- /dev/null
+++ b/activerecord/test/cases/relation/where_test.rb
@@ -0,0 +1,214 @@
+require "cases/helper"
+require 'models/author'
+require 'models/price_estimate'
+require 'models/treasure'
+require 'models/post'
+require 'models/comment'
+require 'models/edge'
+require 'models/topic'
+require 'models/binary'
+
+module ActiveRecord
+  class WhereTest < ActiveRecord::TestCase
+    fixtures :posts, :edges, :authors, :binaries
+
+    def test_where_copies_bind_params
+      author = authors(:david)
+      posts  = author.posts.where('posts.id != 1')
+      joined = Post.where(id: posts)
+
+      assert_operator joined.length, :>, 0
+
+      joined.each { |post|
+        assert_equal author, post.author
+        assert_not_equal 1, post.id
+      }
+    end
+
+    def test_rewhere_on_root
+      assert_equal posts(:welcome), Post.rewhere(title: 'Welcome to the weblog').first
+    end
+
+    def test_belongs_to_shallow_where
+      author = Author.new
+      author.id = 1
+
+      assert_equal Post.where(author_id: 1).to_sql, Post.where(author: author).to_sql
+    end
+
+    def test_belongs_to_nil_where
+      assert_equal Post.where(author_id: nil).to_sql, Post.where(author: nil).to_sql
+    end
+
+    def test_belongs_to_array_value_where
+      assert_equal Post.where(author_id: [1,2]).to_sql, Post.where(author: [1,2]).to_sql
+    end
+
+    def test_belongs_to_nested_relation_where
+      expected = Post.where(author_id: Author.where(id: [1,2])).to_sql
+      actual   = Post.where(author:    Author.where(id: [1,2])).to_sql
+
+      assert_equal expected, actual
+    end
+
+    def test_belongs_to_nested_where
+      parent = Comment.new
+      parent.id = 1
+
+      expected = Post.where(comments: { parent_id: 1 }).joins(:comments)
+      actual   = Post.where(comments: { parent: parent }).joins(:comments)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_shallow_where
+      treasure = Treasure.new
+      treasure.id = 1
+
+      expected = PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: 1)
+      actual   = PriceEstimate.where(estimate_of: treasure)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_nested_array_where
+      treasure = Treasure.new
+      treasure.id = 1
+      hidden = HiddenTreasure.new
+      hidden.id = 2
+
+      expected = PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: [treasure, hidden])
+      actual   = PriceEstimate.where(estimate_of: [treasure, hidden])
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_nested_relation_where
+      expected = PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: Treasure.where(id: [1,2]))
+      actual   = PriceEstimate.where(estimate_of: Treasure.where(id: [1,2]))
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_sti_shallow_where
+      treasure = HiddenTreasure.new
+      treasure.id = 1
+
+      expected = PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: 1)
+      actual   = PriceEstimate.where(estimate_of: treasure)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_nested_where
+      thing = Post.new
+      thing.id = 1
+
+      expected = Treasure.where(price_estimates: { thing_type: 'Post', thing_id: 1 }).joins(:price_estimates)
+      actual   = Treasure.where(price_estimates: { thing: thing }).joins(:price_estimates)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_polymorphic_sti_nested_where
+      treasure = HiddenTreasure.new
+      treasure.id = 1
+
+      expected = Treasure.where(price_estimates: { estimate_of_type: 'Treasure', estimate_of_id: 1 }).joins(:price_estimates)
+      actual   = Treasure.where(price_estimates: { estimate_of: treasure }).joins(:price_estimates)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_decorated_polymorphic_where
+      treasure_decorator = Struct.new(:model) do
+        def self.method_missing(method, *args, &block)
+          Treasure.send(method, *args, &block)
+        end
+
+        def is_a?(klass)
+          model.is_a?(klass)
+        end
+
+        def method_missing(method, *args, &block)
+          model.send(method, *args, &block)
+        end
+      end
+
+      treasure = Treasure.new
+      treasure.id = 1
+      decorated_treasure = treasure_decorator.new(treasure)
+
+      expected = PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: 1)
+      actual   = PriceEstimate.where(estimate_of: decorated_treasure)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_aliased_attribute
+      expected = Topic.where(heading: 'The First Topic')
+      actual   = Topic.where(title: 'The First Topic')
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
+    def test_where_error
+      assert_raises(ActiveRecord::StatementInvalid) do
+        Post.where(:id => { 'posts.author_id' => 10 }).first
+      end
+    end
+
+    def test_where_with_table_name
+      post = Post.first
+      assert_equal post, Post.where(:posts => { 'id' => post.id }).first
+    end
+
+    def test_where_with_table_name_and_empty_hash
+      assert_equal 0, Post.where(:posts => {}).count
+    end
+
+    def test_where_with_table_name_and_empty_array
+      assert_equal 0, Post.where(:id => []).count
+    end
+
+    def test_where_with_empty_hash_and_no_foreign_key
+      assert_equal 0, Edge.where(:sink => {}).count
+    end
+
+    def test_where_with_blank_conditions
+      [[], {}, nil, ""].each do |blank|
+        assert_equal 4, Edge.where(blank).order("sink_id").to_a.size
+      end
+    end
+
+    def test_where_with_integer_for_string_column
+      count = Post.where(:title => 0).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_float_for_string_column
+      count = Post.where(:title => 0.0).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_boolean_for_string_column
+      count = Post.where(:title => false).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_decimal_for_string_column
+      count = Post.where(:title => BigDecimal.new(0)).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_duration_for_string_column
+      count = Post.where(:title => 0.seconds).count
+      assert_equal 0, count
+    end
+
+    def test_where_with_integer_for_binary_column
+      count = Binary.where(:data => 0).count
+      assert_equal 0, count
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation_test.rb b/activerecord/test/cases/relation_test.rb
new file mode 100644
index 0000000000..3280945d09
--- /dev/null
+++ b/activerecord/test/cases/relation_test.rb
@@ -0,0 +1,267 @@
+require "cases/helper"
+require 'models/post'
+require 'models/comment'
+require 'models/author'
+require 'models/rating'
+
+module ActiveRecord
+  class RelationTest < ActiveRecord::TestCase
+    fixtures :posts, :comments, :authors
+
+    class FakeKlass < Struct.new(:table_name, :name)
+      extend ActiveRecord::Delegation::DelegateCache
+
+      inherited self
+
+      def self.connection
+        Post.connection
+      end
+
+      def self.table_name
+        'fake_table'
+      end
+    end
+
+    def test_construction
+      relation = Relation.new FakeKlass, :b
+      assert_equal FakeKlass, relation.klass
+      assert_equal :b, relation.table
+      assert !relation.loaded, 'relation is not loaded'
+    end
+
+    def test_responds_to_model_and_returns_klass
+      relation = Relation.new FakeKlass, :b
+      assert_equal FakeKlass, relation.model
+    end
+
+    def test_initialize_single_values
+      relation = Relation.new FakeKlass, :b
+      (Relation::SINGLE_VALUE_METHODS - [:create_with]).each do |method|
+        assert_nil relation.send("#{method}_value"), method.to_s
+      end
+      assert_equal({}, relation.create_with_value)
+    end
+
+    def test_multi_value_initialize
+      relation = Relation.new FakeKlass, :b
+      Relation::MULTI_VALUE_METHODS.each do |method|
+        assert_equal [], relation.send("#{method}_values"), method.to_s
+      end
+    end
+
+    def test_extensions
+      relation = Relation.new FakeKlass, :b
+      assert_equal [], relation.extensions
+    end
+
+    def test_empty_where_values_hash
+      relation = Relation.new FakeKlass, :b
+      assert_equal({}, relation.where_values_hash)
+
+      relation.where! :hello
+      assert_equal({}, relation.where_values_hash)
+    end
+
+    def test_has_values
+      relation = Relation.new Post, Post.arel_table
+      relation.where! relation.table[:id].eq(10)
+      assert_equal({:id => 10}, relation.where_values_hash)
+    end
+
+    def test_values_wrong_table
+      relation = Relation.new Post, Post.arel_table
+      relation.where! Comment.arel_table[:id].eq(10)
+      assert_equal({}, relation.where_values_hash)
+    end
+
+    def test_tree_is_not_traversed
+      relation = Relation.new Post, Post.arel_table
+      left     = relation.table[:id].eq(10)
+      right    = relation.table[:id].eq(10)
+      combine  = left.and right
+      relation.where! combine
+      assert_equal({}, relation.where_values_hash)
+    end
+
+    def test_table_name_delegates_to_klass
+      relation = Relation.new FakeKlass.new('posts'), :b
+      assert_equal 'posts', relation.table_name
+    end
+
+    def test_scope_for_create
+      relation = Relation.new FakeKlass, :b
+      assert_equal({}, relation.scope_for_create)
+    end
+
+    def test_create_with_value
+      relation = Relation.new Post, Post.arel_table
+      hash = { :hello => 'world' }
+      relation.create_with_value = hash
+      assert_equal hash, relation.scope_for_create
+    end
+
+    def test_create_with_value_with_wheres
+      relation = Relation.new Post, Post.arel_table
+      relation.where! relation.table[:id].eq(10)
+      relation.create_with_value = {:hello => 'world'}
+      assert_equal({:hello => 'world', :id => 10}, relation.scope_for_create)
+    end
+
+    # FIXME: is this really wanted or expected behavior?
+    def test_scope_for_create_is_cached
+      relation = Relation.new Post, Post.arel_table
+      assert_equal({}, relation.scope_for_create)
+
+      relation.where! relation.table[:id].eq(10)
+      assert_equal({}, relation.scope_for_create)
+
+      relation.create_with_value = {:hello => 'world'}
+      assert_equal({}, relation.scope_for_create)
+    end
+
+    def test_bad_constants_raise_errors
+      assert_raises(NameError) do
+        ActiveRecord::Relation::HelloWorld
+      end
+    end
+
+    def test_empty_eager_loading?
+      relation = Relation.new FakeKlass, :b
+      assert !relation.eager_loading?
+    end
+
+    def test_eager_load_values
+      relation = Relation.new FakeKlass, :b
+      relation.eager_load! :b
+      assert relation.eager_loading?
+    end
+
+    def test_references_values
+      relation = Relation.new FakeKlass, :b
+      assert_equal [], relation.references_values
+      relation = relation.references(:foo).references(:omg, :lol)
+      assert_equal ['foo', 'omg', 'lol'], relation.references_values
+    end
+
+    def test_references_values_dont_duplicate
+      relation = Relation.new FakeKlass, :b
+      relation = relation.references(:foo).references(:foo)
+      assert_equal ['foo'], relation.references_values
+    end
+
+    test 'merging a hash into a relation' do
+      relation = Relation.new FakeKlass, :b
+      relation = relation.merge where: :lol, readonly: true
+
+      assert_equal [:lol], relation.where_values
+      assert_equal true, relation.readonly_value
+    end
+
+    test 'merging an empty hash into a relation' do
+      assert_equal [], Relation.new(FakeKlass, :b).merge({}).where_values
+    end
+
+    test 'merging a hash with unknown keys raises' do
+      assert_raises(ArgumentError) { Relation::HashMerger.new(nil, omg: 'lol') }
+    end
+
+    test '#values returns a dup of the values' do
+      relation = Relation.new(FakeKlass, :b).where! :foo
+      values   = relation.values
+
+      values[:where] = nil
+      assert_not_nil relation.where_values
+    end
+
+    test 'relations can be created with a values hash' do
+      relation = Relation.new(FakeKlass, :b, where: [:foo])
+      assert_equal [:foo], relation.where_values
+    end
+
+    test 'merging a single where value' do
+      relation = Relation.new(FakeKlass, :b)
+      relation.merge!(where: :foo)
+      assert_equal [:foo], relation.where_values
+    end
+
+    test 'merging a hash interpolates conditions' do
+      klass = Class.new(FakeKlass) do
+        def self.sanitize_sql(args)
+          raise unless args == ['foo = ?', 'bar']
+          'foo = bar'
+        end
+      end
+
+      relation = Relation.new(klass, :b)
+      relation.merge!(where: ['foo = ?', 'bar'])
+      assert_equal ['foo = bar'], relation.where_values
+    end
+
+    def test_merging_readonly_false
+      relation = Relation.new FakeKlass, :b
+      readonly_false_relation = relation.readonly(false)
+      # test merging in both directions
+      assert_equal false, relation.merge(readonly_false_relation).readonly_value
+      assert_equal false, readonly_false_relation.merge(relation).readonly_value
+    end
+
+    def test_relation_merging_with_merged_joins_as_symbols
+      special_comments_with_ratings = SpecialComment.joins(:ratings)
+      posts_with_special_comments_with_ratings = Post.group("posts.id").joins(:special_comments).merge(special_comments_with_ratings)
+      assert_equal 3, authors(:david).posts.merge(posts_with_special_comments_with_ratings).count.length
+    end
+
+    def test_relation_merging_with_joins_as_join_dependency_pick_proper_parent
+      post = Post.create!(title: "haha", body: "huhu")
+      comment = post.comments.create!(body: "hu")
+      3.times { comment.ratings.create! }
+
+      relation = Post.joins(:comments).merge Comment.joins(:ratings)
+
+      assert_equal 3, relation.where(id: post.id).pluck(:id).size
+    end
+
+    def test_respond_to_for_non_selected_element
+      post = Post.select(:title).first
+      assert_equal false, post.respond_to?(:body), "post should not respond_to?(:body) since invoking it raises exception"
+
+      silence_warnings { post = Post.select("'title' as post_title").first }
+      assert_equal false, post.respond_to?(:title), "post should not respond_to?(:body) since invoking it raises exception"
+    end
+
+    def test_relation_merging_with_merged_joins_as_strings
+      join_string = "LEFT OUTER JOIN #{Rating.quoted_table_name} ON #{SpecialComment.quoted_table_name}.id = #{Rating.quoted_table_name}.comment_id"
+      special_comments_with_ratings = SpecialComment.joins join_string
+      posts_with_special_comments_with_ratings = Post.group("posts.id").joins(:special_comments).merge(special_comments_with_ratings)
+      assert_equal 3, authors(:david).posts.merge(posts_with_special_comments_with_ratings).count.length
+    end
+
+    class EnsureRoundTripTypeCasting < ActiveRecord::Type::Value
+      def type
+        :string
+      end
+
+      def type_cast_from_database(value)
+        raise value unless value == "type cast for database"
+        "type cast from database"
+      end
+
+      def type_cast_for_database(value)
+        raise value unless value == "value from user"
+        "type cast for database"
+      end
+    end
+
+    class UpdateAllTestModel < ActiveRecord::Base
+      self.table_name = 'posts'
+
+      attribute :body, EnsureRoundTripTypeCasting.new
+    end
+
+    def test_update_all_goes_through_normal_type_casting
+      UpdateAllTestModel.update_all(body: "value from user", type: nil) # No STI
+
+      assert_equal "type cast from database", UpdateAllTestModel.first.body
+    end
+  end
+end
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
new file mode 100644
index 0000000000..88df997a2f
--- /dev/null
+++ b/activerecord/test/cases/relations_test.rb
@@ -0,0 +1,1739 @@
+require "cases/helper"
+require 'models/tag'
+require 'models/tagging'
+require 'models/post'
+require 'models/topic'
+require 'models/comment'
+require 'models/author'
+require 'models/entrant'
+require 'models/developer'
+require 'models/reply'
+require 'models/company'
+require 'models/bird'
+require 'models/car'
+require 'models/engine'
+require 'models/tyre'
+require 'models/minivan'
+require 'models/aircraft'
+
+
+class RelationTest < ActiveRecord::TestCase
+  fixtures :authors, :topics, :entrants, :developers, :companies, :developers_projects, :accounts, :categories, :categorizations, :posts, :comments,
+    :tags, :taggings, :cars, :minivans
+
+  def test_do_not_double_quote_string_id
+    van = Minivan.last
+    assert van
+    assert_equal van.id, Minivan.where(:minivan_id => van).to_a.first.minivan_id
+  end
+
+  def test_do_not_double_quote_string_id_with_array
+    van = Minivan.last
+    assert van
+    assert_equal van, Minivan.where(:minivan_id => [van]).to_a.first
+  end
+
+  def test_bind_values
+    relation = Post.all
+    assert_equal [], relation.bind_values
+
+    relation2 = relation.bind 'foo'
+    assert_equal %w{ foo }, relation2.bind_values
+    assert_equal [], relation.bind_values
+  end
+
+  def test_two_scopes_with_includes_should_not_drop_any_include
+    # heat habtm cache
+    car = Car.incl_engines.incl_tyres.first
+    car.tyres.length
+    car.engines.length
+
+    car = Car.incl_engines.incl_tyres.first
+    assert_no_queries { car.tyres.length }
+    assert_no_queries { car.engines.length }
+  end
+
+  def test_dynamic_finder
+    x = Post.where('author_id = ?', 1)
+    assert x.klass.respond_to?(:find_by_id), '@klass should handle dynamic finders'
+  end
+
+  def test_multivalue_where
+    posts = Post.where('author_id = ? AND id = ?', 1, 1)
+    assert_equal 1, posts.to_a.size
+  end
+
+  def test_scoped
+    topics = Topic.all
+    assert_kind_of ActiveRecord::Relation, topics
+    assert_equal 5, topics.size
+  end
+
+  def test_to_json
+    assert_nothing_raised  { Bird.all.to_json }
+    assert_nothing_raised  { Bird.all.to_a.to_json }
+  end
+
+  def test_to_yaml
+    assert_nothing_raised  { Bird.all.to_yaml }
+    assert_nothing_raised  { Bird.all.to_a.to_yaml }
+  end
+
+  def test_to_xml
+    assert_nothing_raised  { Bird.all.to_xml }
+    assert_nothing_raised  { Bird.all.to_a.to_xml }
+  end
+
+  def test_scoped_all
+    topics = Topic.all.to_a
+    assert_kind_of Array, topics
+    assert_no_queries { assert_equal 5, topics.size }
+  end
+
+  def test_loaded_all
+    topics = Topic.all
+
+    assert_queries(1) do
+      2.times { assert_equal 5, topics.to_a.size }
+    end
+
+    assert topics.loaded?
+  end
+
+  def test_scoped_first
+    topics = Topic.all.order('id ASC')
+
+    assert_queries(1) do
+      2.times { assert_equal "The First Topic", topics.first.title }
+    end
+
+    assert ! topics.loaded?
+  end
+
+  def test_loaded_first
+    topics = Topic.all.order('id ASC')
+
+    assert_queries(1) do
+      topics.to_a # force load
+      2.times { assert_equal "The First Topic", topics.first.title }
+    end
+
+    assert topics.loaded?
+  end
+
+  def test_reload
+    topics = Topic.all
+
+    assert_queries(1) do
+      2.times { topics.to_a }
+    end
+
+    assert topics.loaded?
+
+    original_size = topics.to_a.size
+    Topic.create! :title => 'fake'
+
+    assert_queries(1) { topics.reload }
+    assert_equal original_size + 1, topics.size
+    assert topics.loaded?
+  end
+
+  def test_finding_with_subquery
+    relation = Topic.where(:approved => true)
+    assert_equal relation.to_a, Topic.select('*').from(relation).to_a
+    assert_equal relation.to_a, Topic.select('subquery.*').from(relation).to_a
+    assert_equal relation.to_a, Topic.select('a.*').from(relation, :a).to_a
+  end
+
+  def test_finding_with_subquery_with_binds
+    relation = Post.first.comments
+    assert_equal relation.to_a, Comment.select('*').from(relation).to_a
+    assert_equal relation.to_a, Comment.select('subquery.*').from(relation).to_a
+    assert_equal relation.to_a, Comment.select('a.*').from(relation, :a).to_a
+  end
+
+  def test_finding_with_subquery_without_select_does_not_change_the_select
+    relation = Topic.where(approved: true)
+    assert_raises(ActiveRecord::StatementInvalid) do
+      Topic.from(relation).to_a
+    end
+  end
+
+
+  def test_finding_with_conditions
+    assert_equal ["David"], Author.where(:name => 'David').map(&:name)
+    assert_equal ['Mary'],  Author.where(["name = ?", 'Mary']).map(&:name)
+    assert_equal ['Mary'],  Author.where("name = ?", 'Mary').map(&:name)
+  end
+
+  def test_finding_with_order
+    topics = Topic.order('id')
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:first).title, topics.first.title
+  end
+
+  def test_finding_with_arel_order
+    topics = Topic.order(Topic.arel_table[:id].asc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:first).title, topics.first.title
+  end
+
+  def test_finding_with_assoc_order
+    topics = Topic.order(:id => :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_reverted_assoc_order
+    topics = Topic.order(:id => :asc).reverse_order
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_order_with_hash_and_symbol_generates_the_same_sql
+    assert_equal Topic.order(:id).to_sql, Topic.order(:id => :asc).to_sql
+  end
+
+  def test_finding_with_desc_order_with_string
+    topics = Topic.order(id: "desc")
+    assert_equal 5, topics.to_a.size
+    assert_equal [topics(:fifth), topics(:fourth), topics(:third), topics(:second), topics(:first)], topics.to_a
+  end
+
+  def test_finding_with_asc_order_with_string
+    topics = Topic.order(id: 'asc')
+    assert_equal 5, topics.to_a.size
+    assert_equal [topics(:first), topics(:second), topics(:third), topics(:fourth), topics(:fifth)], topics.to_a
+  end
+
+  def test_support_upper_and_lower_case_directions
+    assert_includes Topic.order(id: "ASC").to_sql, "ASC"
+    assert_includes Topic.order(id: "asc").to_sql, "ASC"
+    assert_includes Topic.order(id: :ASC).to_sql, "ASC"
+    assert_includes Topic.order(id: :asc).to_sql, "ASC"
+
+    assert_includes Topic.order(id: "DESC").to_sql, "DESC"
+    assert_includes Topic.order(id: "desc").to_sql, "DESC"
+    assert_includes Topic.order(id: :DESC).to_sql, "DESC"
+    assert_includes Topic.order(id: :desc).to_sql,"DESC"
+  end
+
+  def test_raising_exception_on_invalid_hash_params
+    e = assert_raise(ArgumentError) { Topic.order(:name, "id DESC", id: :asfsdf) }
+    assert_equal 'Direction "asfsdf" is invalid. Valid directions are: [:asc, :desc, :ASC, :DESC, "asc", "desc", "ASC", "DESC"]', e.message
+  end
+
+  def test_finding_last_with_arel_order
+    topics = Topic.order(Topic.arel_table[:id].asc)
+    assert_equal topics(:fifth).title, topics.last.title
+  end
+
+  def test_finding_with_order_concatenated
+    topics = Topic.order('author_name').order('title')
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fourth).title, topics.first.title
+  end
+
+  def test_finding_with_order_by_aliased_attributes
+    topics = Topic.order(:heading)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_assoc_order_by_aliased_attributes
+    topics = Topic.order(heading: :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:third).title, topics.first.title
+  end
+
+  def test_finding_with_reorder
+    topics = Topic.order('author_name').order('title').reorder('id').to_a
+    topics_titles = topics.map{ |t| t.title }
+    assert_equal ['The First Topic', 'The Second Topic of the day', 'The Third Topic of the day', 'The Fourth Topic of the day', 'The Fifth Topic of the day'], topics_titles
+  end
+
+  def test_finding_with_reorder_by_aliased_attributes
+    topics = Topic.order('author_name').reorder(:heading)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_assoc_reorder_by_aliased_attributes
+    topics = Topic.order('author_name').reorder(heading: :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:third).title, topics.first.title
+  end
+
+  def test_finding_with_order_and_take
+    entrants = Entrant.order("id ASC").limit(2).to_a
+
+    assert_equal 2, entrants.size
+    assert_equal entrants(:first).name, entrants.first.name
+  end
+
+  def test_finding_with_cross_table_order_and_limit
+    tags = Tag.includes(:taggings).
+              order("tags.name asc", "taggings.taggable_id asc", "REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").
+              limit(1).to_a
+    assert_equal 1, tags.length
+  end
+
+  def test_finding_with_complex_order_and_limit
+    tags = Tag.includes(:taggings).references(:taggings).order("REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").limit(1).to_a
+    assert_equal 1, tags.length
+  end
+
+  def test_finding_with_complex_order
+    tags = Tag.includes(:taggings).references(:taggings).order("REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").to_a
+    assert_equal 3, tags.length
+  end
+
+  def test_finding_with_order_limit_and_offset
+    entrants = Entrant.order("id ASC").limit(2).offset(1)
+
+    assert_equal 2, entrants.to_a.size
+    assert_equal entrants(:second).name, entrants.first.name
+
+    entrants = Entrant.order("id ASC").limit(2).offset(2)
+    assert_equal 1, entrants.to_a.size
+    assert_equal entrants(:third).name, entrants.first.name
+  end
+
+  def test_finding_with_group
+    developers = Developer.group("salary").select("salary").to_a
+    assert_equal 4, developers.size
+    assert_equal 4, developers.map(&:salary).uniq.size
+  end
+
+  def test_select_with_block
+    even_ids = Developer.all.select {|d| d.id % 2 == 0 }.map(&:id)
+    assert_equal [2, 4, 6, 8, 10], even_ids.sort
+  end
+
+  def test_none
+    assert_no_queries do
+      assert_equal [], Developer.none
+      assert_equal [], Developer.all.none
+    end
+  end
+
+  def test_none_chainable
+    assert_no_queries do
+      assert_equal [], Developer.none.where(:name => 'David')
+    end
+  end
+
+  def test_none_chainable_to_existing_scope_extension_method
+    assert_no_queries do
+      assert_equal 1, Topic.anonymous_extension.none.one
+    end
+  end
+
+  def test_none_chained_to_methods_firing_queries_straight_to_db
+    assert_no_queries do
+      assert_equal [],    Developer.none.pluck(:id, :name)
+      assert_equal 0,     Developer.none.delete_all
+      assert_equal 0,     Developer.none.update_all(:name => 'David')
+      assert_equal 0,     Developer.none.delete(1)
+      assert_equal false, Developer.none.exists?(1)
+    end
+  end
+
+  def test_null_relation_content_size_methods
+    assert_no_queries do
+      assert_equal 0,     Developer.none.size
+      assert_equal 0,     Developer.none.count
+      assert_equal true,  Developer.none.empty?
+      assert_equal false, Developer.none.any?
+      assert_equal false, Developer.none.many?
+    end
+  end
+
+  def test_null_relation_calculations_methods
+    assert_no_queries do
+      assert_equal 0, Developer.none.count
+      assert_equal 0, Developer.none.calculate(:count, nil, {})
+      assert_equal nil, Developer.none.calculate(:average, 'salary')
+    end
+  end
+
+  def test_null_relation_metadata_methods
+    assert_equal "", Developer.none.to_sql
+    assert_equal({}, Developer.none.where_values_hash)
+  end
+
+  def test_null_relation_where_values_hash
+    assert_equal({ 'salary' => 100_000 }, Developer.none.where(salary: 100_000).where_values_hash)
+  end
+
+  def test_null_relation_sum
+    ac = Aircraft.new
+    assert_equal Hash.new, ac.engines.group(:id).sum(:id)
+    assert_equal        0, ac.engines.count
+    ac.save
+    assert_equal Hash.new, ac.engines.group(:id).sum(:id)
+    assert_equal        0, ac.engines.count
+  end
+
+  def test_null_relation_count
+    ac = Aircraft.new
+    assert_equal Hash.new, ac.engines.group(:id).count
+    assert_equal        0, ac.engines.count
+    ac.save
+    assert_equal Hash.new, ac.engines.group(:id).count
+    assert_equal        0, ac.engines.count
+  end
+
+  def test_null_relation_size
+    ac = Aircraft.new
+    assert_equal Hash.new, ac.engines.group(:id).size
+    assert_equal        0, ac.engines.size
+    ac.save
+    assert_equal Hash.new, ac.engines.group(:id).size
+    assert_equal        0, ac.engines.size
+  end
+
+  def test_null_relation_average
+    ac = Aircraft.new
+    assert_equal Hash.new, ac.engines.group(:car_id).average(:id)
+    assert_equal        nil, ac.engines.average(:id)
+    ac.save
+    assert_equal Hash.new, ac.engines.group(:car_id).average(:id)
+    assert_equal        nil, ac.engines.average(:id)
+  end
+
+  def test_null_relation_minimum
+    ac = Aircraft.new
+    assert_equal Hash.new, ac.engines.group(:car_id).minimum(:id)
+    assert_equal        nil, ac.engines.minimum(:id)
+    ac.save
+    assert_equal Hash.new, ac.engines.group(:car_id).minimum(:id)
+    assert_equal        nil, ac.engines.minimum(:id)
+  end
+
+  def test_null_relation_maximum
+    ac = Aircraft.new
+    assert_equal Hash.new, ac.engines.group(:car_id).maximum(:id)
+    assert_equal        nil, ac.engines.maximum(:id)
+    ac.save
+    assert_equal Hash.new, ac.engines.group(:car_id).maximum(:id)
+    assert_equal        nil, ac.engines.maximum(:id)
+  end
+
+  def test_joins_with_nil_argument
+    assert_nothing_raised { DependentFirm.joins(nil).first }
+  end
+
+  def test_finding_with_hash_conditions_on_joined_table
+    firms = DependentFirm.joins(:account).where({:name => 'RailsCore', :accounts => { :credit_limit => 55..60 }}).to_a
+    assert_equal 1, firms.size
+    assert_equal companies(:rails_core), firms.first
+  end
+
+  def test_find_all_with_join
+    developers_on_project_one = Developer.joins('LEFT JOIN developers_projects ON developers.id = developers_projects.developer_id').
+      where('project_id=1').to_a
+
+    assert_equal 3, developers_on_project_one.length
+    developer_names = developers_on_project_one.map { |d| d.name }
+    assert developer_names.include?('David')
+    assert developer_names.include?('Jamis')
+  end
+
+  def test_find_on_hash_conditions
+    assert_equal Topic.all.merge!(:where => {:approved => false}).to_a, Topic.where({ :approved => false }).to_a
+  end
+
+  def test_joins_with_string_array
+    person_with_reader_and_post = Post.joins([
+        "INNER JOIN categorizations ON categorizations.post_id = posts.id",
+        "INNER JOIN categories ON categories.id = categorizations.category_id AND categories.type = 'SpecialCategory'"
+      ]
+    ).to_a
+    assert_equal 1, person_with_reader_and_post.size
+  end
+
+  def test_no_arguments_to_query_methods_raise_errors
+    assert_raises(ArgumentError) { Topic.references() }
+    assert_raises(ArgumentError) { Topic.includes() }
+    assert_raises(ArgumentError) { Topic.preload() }
+    assert_raises(ArgumentError) { Topic.group() }
+    assert_raises(ArgumentError) { Topic.reorder() }
+  end
+
+  def test_blank_like_arguments_to_query_methods_dont_raise_errors
+    assert_nothing_raised { Topic.references([]) }
+    assert_nothing_raised { Topic.includes([]) }
+    assert_nothing_raised { Topic.preload([]) }
+    assert_nothing_raised { Topic.group([]) }
+    assert_nothing_raised { Topic.reorder([]) }
+  end
+
+  def test_scoped_responds_to_delegated_methods
+    relation = Topic.all
+
+    ["map", "uniq", "sort", "insert", "delete", "update"].each do |method|
+      assert_respond_to relation, method, "Topic.all should respond to #{method.inspect}"
+    end
+  end
+
+  def test_respond_to_delegates_to_relation
+    relation = Topic.all
+    fake_arel = Struct.new(:responds) {
+      def respond_to? method, access = false
+        responds << [method, access]
+      end
+    }.new []
+
+    relation.extend(Module.new { attr_accessor :arel })
+    relation.arel = fake_arel
+
+    relation.respond_to?(:matching_attributes)
+    assert_equal [:matching_attributes, false], fake_arel.responds.first
+
+    fake_arel.responds = []
+    relation.respond_to?(:matching_attributes, true)
+    assert_equal [:matching_attributes, true], fake_arel.responds.first
+  end
+
+  def test_respond_to_dynamic_finders
+    relation = Topic.all
+
+    ["find_by_title", "find_by_title_and_author_name"].each do |method|
+      assert_respond_to relation, method, "Topic.all should respond to #{method.inspect}"
+    end
+  end
+
+  def test_respond_to_class_methods_and_scopes
+    assert Topic.all.respond_to?(:by_lifo)
+  end
+
+  def test_find_with_readonly_option
+    Developer.all.each { |d| assert !d.readonly? }
+    Developer.all.readonly.each { |d| assert d.readonly? }
+  end
+
+  def test_eager_association_loading_of_stis_with_multiple_references
+    authors = Author.eager_load(:posts => { :special_comments => { :post => [ :special_comments, :very_special_comment ] } }).
+      order('comments.body, very_special_comments_posts.body').where('posts.id = 4').to_a
+
+    assert_equal [authors(:david)], authors
+    assert_no_queries do
+      authors.first.posts.first.special_comments.first.post.special_comments
+      authors.first.posts.first.special_comments.first.post.very_special_comment
+    end
+  end
+
+  def test_find_with_preloaded_associations
+    assert_queries(2) do
+      posts = Post.preload(:comments).order('posts.id')
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.preload(:comments).order('posts.id')
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.preload(:author).order('posts.id')
+      assert posts.first.author
+    end
+
+    assert_queries(2) do
+      posts = Post.preload(:author).order('posts.id')
+      assert posts.first.author
+    end
+
+    assert_queries(3) do
+      posts = Post.preload(:author, :comments).order('posts.id')
+      assert posts.first.author
+      assert posts.first.comments.first
+    end
+  end
+
+  def test_preload_applies_to_all_chained_preloaded_scopes
+    assert_queries(3) do
+      post = Post.with_comments.with_tags.first
+      assert post
+    end
+  end
+
+  def test_find_with_included_associations
+    assert_queries(2) do
+      posts = Post.includes(:comments).order('posts.id')
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.all.includes(:comments).order('posts.id')
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.includes(:author).order('posts.id')
+      assert posts.first.author
+    end
+
+    assert_queries(3) do
+      posts = Post.includes(:author, :comments).order('posts.id')
+      assert posts.first.author
+      assert posts.first.comments.first
+    end
+  end
+
+  def test_default_scope_with_conditions_string
+    assert_equal Developer.where(name: 'David').map(&:id).sort, DeveloperCalledDavid.all.map(&:id).sort
+    assert_nil DeveloperCalledDavid.create!.name
+  end
+
+  def test_default_scope_with_conditions_hash
+    assert_equal Developer.where(name: 'Jamis').map(&:id).sort, DeveloperCalledJamis.all.map(&:id).sort
+    assert_equal 'Jamis', DeveloperCalledJamis.create!.name
+  end
+
+  def test_default_scoping_finder_methods
+    developers = DeveloperCalledDavid.order('id').map(&:id).sort
+    assert_equal Developer.where(name: 'David').map(&:id).sort, developers
+  end
+
+  def test_includes_with_select
+    query = Post.select('comments_count AS ranking').order('ranking').includes(:comments)
+      .where(comments: { id: 1 })
+
+    assert_equal ['comments_count AS ranking'], query.select_values
+    assert_equal 1, query.to_a.size
+  end
+
+  def test_loading_with_one_association
+    posts = Post.preload(:comments)
+    post = posts.find { |p| p.id == 1 }
+    assert_equal 2, post.comments.size
+    assert post.comments.include?(comments(:greetings))
+
+    post = Post.where("posts.title = 'Welcome to the weblog'").preload(:comments).first
+    assert_equal 2, post.comments.size
+    assert post.comments.include?(comments(:greetings))
+
+    posts = Post.preload(:last_comment)
+    post = posts.find { |p| p.id == 1 }
+    assert_equal Post.find(1).last_comment, post.last_comment
+  end
+
+  def test_to_sql_on_eager_join
+    expected = assert_sql {
+      Post.eager_load(:last_comment).order('comments.id DESC').to_a
+    }.first
+    actual = Post.eager_load(:last_comment).order('comments.id DESC').to_sql
+    assert_equal expected, actual
+  end
+
+  def test_to_sql_on_scoped_proxy
+    auth = Author.first
+    Post.where("1=1").written_by(auth)
+    assert_not auth.posts.to_sql.include?("1=1")
+  end
+
+  def test_loading_with_one_association_with_non_preload
+    posts = Post.eager_load(:last_comment).order('comments.id DESC')
+    post = posts.find { |p| p.id == 1 }
+    assert_equal Post.find(1).last_comment, post.last_comment
+  end
+
+  def test_dynamic_find_by_attributes
+    david = authors(:david)
+    author = Author.preload(:taggings).find_by_id(david.id)
+    expected_taggings = taggings(:welcome_general, :thinking_general)
+
+    assert_no_queries do
+      assert_equal expected_taggings, author.taggings.distinct.sort_by { |t| t.id }
+      assert_equal expected_taggings, author.taggings.uniq.sort_by { |t| t.id }
+    end
+
+    authors = Author.all
+    assert_equal david, authors.find_by_id_and_name(david.id, david.name)
+    assert_equal david, authors.find_by_id_and_name!(david.id, david.name)
+  end
+
+  def test_dynamic_find_by_attributes_bang
+    author = Author.all.find_by_id!(authors(:david).id)
+    assert_equal "David", author.name
+
+    assert_raises(ActiveRecord::RecordNotFound) { Author.all.find_by_id_and_name!(20, 'invalid') }
+  end
+
+  def test_find_id
+    authors = Author.all
+
+    david = authors.find(authors(:david).id)
+    assert_equal 'David', david.name
+
+    assert_raises(ActiveRecord::RecordNotFound) { authors.where(:name => 'lifo').find('42') }
+  end
+
+  def test_find_ids
+    authors = Author.order('id ASC')
+
+    results = authors.find(authors(:david).id, authors(:mary).id)
+    assert_kind_of Array, results
+    assert_equal 2, results.size
+    assert_equal 'David', results[0].name
+    assert_equal 'Mary', results[1].name
+    assert_equal results, authors.find([authors(:david).id, authors(:mary).id])
+
+    assert_raises(ActiveRecord::RecordNotFound) { authors.where(:name => 'lifo').find(authors(:david).id, '42') }
+    assert_raises(ActiveRecord::RecordNotFound) { authors.find(['42', 43]) }
+  end
+
+  def test_find_in_empty_array
+    authors = Author.all.where(:id => [])
+    assert authors.to_a.blank?
+  end
+
+  def test_where_with_ar_object
+    author = Author.first
+    authors = Author.all.where(:id => author)
+    assert_equal 1, authors.to_a.length
+  end
+
+  def test_find_with_list_of_ar
+    author = Author.first
+    authors = Author.find([author.id])
+    assert_equal author, authors.first
+  end
+
+  class Mary < Author; end
+
+  def test_find_by_classname
+    Author.create!(:name => Mary.name)
+    assert_equal 1, Author.where(:name => Mary).size
+  end
+
+  def test_find_by_id_with_list_of_ar
+    author = Author.first
+    authors = Author.find_by_id([author])
+    assert_equal author, authors
+  end
+
+  def test_find_all_using_where_twice_should_or_the_relation
+    david = authors(:david)
+    relation = Author.unscoped
+    relation = relation.where(:name => david.name)
+    relation = relation.where(:name => 'Santiago')
+    relation = relation.where(:id => david.id)
+    assert_equal [], relation.to_a
+  end
+
+  def test_multi_where_ands_queries
+    relation = Author.unscoped
+    david = authors(:david)
+    sql = relation.where(:name => david.name).where(:name => 'Santiago').to_sql
+    assert_match('AND', sql)
+  end
+
+  def test_find_all_with_multiple_should_use_and
+    david = authors(:david)
+    relation = [
+      { :name => david.name },
+      { :name => 'Santiago' },
+      { :name => 'tenderlove' },
+    ].inject(Author.unscoped) do |memo, param|
+      memo.where(param)
+    end
+    assert_equal [], relation.to_a
+  end
+
+  def test_typecasting_where_with_array
+    ids = Author.pluck(:id)
+    slugs = ids.map { |id| "#{id}-as-a-slug" }
+
+    assert_equal Author.all.to_a, Author.where(id: slugs).to_a
+  end
+
+  def test_find_all_using_where_with_relation
+    david = authors(:david)
+    # switching the lines below would succeed in current rails
+    # assert_queries(2) {
+    assert_queries(1) {
+      relation = Author.where(:id => Author.where(:id => david.id))
+      assert_equal [david], relation.to_a
+    }
+
+    assert_queries(1) {
+      relation = Author.where('id in (?)', Author.where(id: david).select(:id))
+      assert_equal [david], relation.to_a
+    }
+
+    assert_queries(1) do
+      relation = Author.where('id in (:author_ids)', author_ids: Author.where(id: david).select(:id))
+      assert_equal [david], relation.to_a
+    end
+  end
+
+  def test_find_all_using_where_with_relation_with_bound_values
+    david = authors(:david)
+    davids_posts = david.posts.order(:id).to_a
+
+    assert_queries(1) do
+      relation = Post.where(id: david.posts.select(:id))
+      assert_equal davids_posts, relation.order(:id).to_a
+    end
+
+    assert_queries(1) do
+      relation = Post.where('id in (?)', david.posts.select(:id))
+      assert_equal davids_posts, relation.order(:id).to_a, 'should process Relation as bind variables'
+    end
+
+    assert_queries(1) do
+      relation = Post.where('id in (:post_ids)', post_ids: david.posts.select(:id))
+      assert_equal davids_posts, relation.order(:id).to_a, 'should process Relation as named bind variables'
+    end
+  end
+
+  def test_find_all_using_where_with_relation_and_alternate_primary_key
+    cool_first = minivans(:cool_first)
+    # switching the lines below would succeed in current rails
+    # assert_queries(2) {
+    assert_queries(1) {
+      relation = Minivan.where(:minivan_id => Minivan.where(:name => cool_first.name))
+      assert_equal [cool_first], relation.to_a
+    }
+  end
+
+  def test_find_all_using_where_with_relation_does_not_alter_select_values
+    david = authors(:david)
+
+    subquery = Author.where(:id => david.id)
+
+    assert_queries(1) {
+      relation = Author.where(:id => subquery)
+      assert_equal [david], relation.to_a
+    }
+
+    assert_equal 0, subquery.select_values.size
+  end
+
+  def test_find_all_using_where_with_relation_with_joins
+    david = authors(:david)
+    assert_queries(1) {
+      relation = Author.where(:id => Author.joins(:posts).where(:id => david.id))
+      assert_equal [david], relation.to_a
+    }
+  end
+
+
+  def test_find_all_using_where_with_relation_with_select_to_build_subquery
+    david = authors(:david)
+    assert_queries(1) {
+      relation = Author.where(:name => Author.where(:id => david.id).select(:name))
+      assert_equal [david], relation.to_a
+    }
+  end
+
+  def test_exists
+    davids = Author.where(:name => 'David')
+    assert davids.exists?
+    assert davids.exists?(authors(:david).id)
+    assert ! davids.exists?(authors(:mary).id)
+    assert ! davids.exists?("42")
+    assert ! davids.exists?(42)
+    assert ! davids.exists?(davids.new.id)
+
+    fake  = Author.where(:name => 'fake author')
+    assert ! fake.exists?
+    assert ! fake.exists?(authors(:david).id)
+  end
+
+  def test_last
+    authors = Author.all
+    assert_equal authors(:bob), authors.last
+  end
+
+  def test_destroy_all
+    davids = Author.where(:name => 'David')
+
+    # Force load
+    assert_equal [authors(:david)], davids.to_a
+    assert davids.loaded?
+
+    assert_difference('Author.count', -1) { davids.destroy_all }
+
+    assert_equal [], davids.to_a
+    assert davids.loaded?
+  end
+
+  def test_delete_all
+    davids = Author.where(:name => 'David')
+
+    assert_difference('Author.count', -1) { davids.delete_all }
+    assert ! davids.loaded?
+  end
+
+  def test_delete_all_loaded
+    davids = Author.where(:name => 'David')
+
+    # Force load
+    assert_equal [authors(:david)], davids.to_a
+    assert davids.loaded?
+
+    assert_difference('Author.count', -1) { davids.delete_all }
+
+    assert_equal [], davids.to_a
+    assert davids.loaded?
+  end
+
+  def test_delete_all_with_unpermitted_relation_raises_error
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.limit(10).delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.uniq.delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.group(:name).delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.having('SUM(id) < 3').delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.offset(10).delete_all }
+  end
+
+  def test_select_with_aggregates
+    posts = Post.select(:title, :body)
+
+    assert_equal 11, posts.count(:all)
+    assert_equal 11, posts.size
+    assert posts.any?
+    assert posts.many?
+    assert_not posts.empty?
+  end
+
+  def test_select_takes_a_variable_list_of_args
+    david = developers(:david)
+
+    developer = Developer.where(id: david.id).select(:name, :salary).first
+    assert_equal david.name, developer.name
+    assert_equal david.salary, developer.salary
+  end
+
+  def test_select_takes_an_aliased_attribute
+    first = topics(:first)
+
+    topic = Topic.where(id: first.id).select(:heading).first
+    assert_equal first.heading, topic.heading
+  end
+
+  def test_select_argument_error
+    assert_raises(ArgumentError) { Developer.select }
+  end
+
+  def test_count
+    posts = Post.all
+
+    assert_equal 11, posts.count
+    assert_equal 11, posts.count(:all)
+    assert_equal 11, posts.count(:id)
+
+    assert_equal 1, posts.where('comments_count > 1').count
+    assert_equal 9, posts.where(:comments_count => 0).count
+  end
+
+  def test_count_on_association_relation
+    author = Author.last
+    another_author = Author.first
+    posts = Post.where(author_id: author.id)
+
+    assert_equal author.posts.where(author_id: author.id).size, posts.count
+
+    assert_equal 0, author.posts.where(author_id: another_author.id).size
+    assert author.posts.where(author_id: another_author.id).empty?
+  end
+
+  def test_count_with_distinct
+    posts = Post.all
+
+    assert_equal 3, posts.distinct(true).count(:comments_count)
+    assert_equal 11, posts.distinct(false).count(:comments_count)
+
+    assert_equal 3, posts.distinct(true).select(:comments_count).count
+    assert_equal 11, posts.distinct(false).select(:comments_count).count
+  end
+
+  def test_update_all_with_scope
+    tag = Tag.first
+    Post.tagged_with(tag.id).update_all title: "rofl"
+    list = Post.tagged_with(tag.id).all.to_a
+    assert_operator list.length, :>, 0
+    list.each { |post| assert_equal 'rofl', post.title }
+  end
+
+  def test_count_explicit_columns
+    Post.update_all(:comments_count => nil)
+    posts = Post.all
+
+    assert_equal [0], posts.select('comments_count').where('id is not null').group('id').order('id').count.values.uniq
+    assert_equal 0, posts.where('id is not null').select('comments_count').count
+
+    assert_equal 11, posts.select('comments_count').count('id')
+    assert_equal 0, posts.select('comments_count').count
+    assert_equal 0, posts.count(:comments_count)
+    assert_equal 0, posts.count('comments_count')
+  end
+
+  def test_multiple_selects
+    post = Post.all.select('comments_count').select('title').order("id ASC").first
+    assert_equal "Welcome to the weblog", post.title
+    assert_equal 2, post.comments_count
+  end
+
+  def test_size
+    posts = Post.all
+
+    assert_queries(1) { assert_equal 11, posts.size }
+    assert ! posts.loaded?
+
+    best_posts = posts.where(:comments_count => 0)
+    best_posts.to_a # force load
+    assert_no_queries { assert_equal 9, best_posts.size }
+  end
+
+  def test_size_with_limit
+    posts = Post.limit(10)
+
+    assert_queries(1) { assert_equal 10, posts.size }
+    assert ! posts.loaded?
+
+    best_posts = posts.where(:comments_count => 0)
+    best_posts.to_a # force load
+    assert_no_queries { assert_equal 9, best_posts.size }
+  end
+
+  def test_size_with_zero_limit
+    posts = Post.limit(0)
+
+    assert_no_queries { assert_equal 0, posts.size }
+    assert ! posts.loaded?
+
+    posts.to_a # force load
+    assert_no_queries { assert_equal 0, posts.size }
+  end
+
+  def test_empty_with_zero_limit
+    posts = Post.limit(0)
+
+    assert_no_queries { assert_equal true, posts.empty? }
+    assert ! posts.loaded?
+  end
+
+  def test_count_complex_chained_relations
+    posts = Post.select('comments_count').where('id is not null').group("author_id").where("comments_count > 0")
+
+    expected = { 1 => 2 }
+    assert_equal expected, posts.count
+  end
+
+  def test_empty
+    posts = Post.all
+
+    assert_queries(1) { assert_equal false, posts.empty? }
+    assert ! posts.loaded?
+
+    no_posts = posts.where(:title => "")
+    assert_queries(1) { assert_equal true, no_posts.empty? }
+    assert ! no_posts.loaded?
+
+    best_posts = posts.where(:comments_count => 0)
+    best_posts.to_a # force load
+    assert_no_queries { assert_equal false, best_posts.empty? }
+  end
+
+  def test_empty_complex_chained_relations
+    posts = Post.select("comments_count").where("id is not null").group("author_id").where("comments_count > 0")
+
+    assert_queries(1) { assert_equal false, posts.empty? }
+    assert ! posts.loaded?
+
+    no_posts = posts.where(:title => "")
+    assert_queries(1) { assert_equal true, no_posts.empty? }
+    assert ! no_posts.loaded?
+  end
+
+  def test_any
+    posts = Post.all
+
+    # This test was failing when run on its own (as opposed to running the entire suite).
+    # The second line in the assert_queries block was causing visit_Arel_Attributes_Attribute
+    # in Arel::Visitors::ToSql to trigger a SHOW TABLES query. Running that line here causes
+    # the SHOW TABLES result to be cached so we don't have to do it again in the block.
+    #
+    # This is obviously a rubbish fix but it's the best I can come up with for now...
+    posts.where(:id => nil).any?
+
+    assert_queries(3) do
+      assert posts.any? # Uses COUNT()
+      assert ! posts.where(:id => nil).any?
+
+      assert posts.any? {|p| p.id > 0 }
+      assert ! posts.any? {|p| p.id <= 0 }
+    end
+
+    assert posts.loaded?
+  end
+
+  def test_many
+    posts = Post.all
+
+    assert_queries(2) do
+      assert posts.many? # Uses COUNT()
+      assert posts.many? {|p| p.id > 0 }
+      assert ! posts.many? {|p| p.id < 2 }
+    end
+
+    assert posts.loaded?
+  end
+
+  def test_many_with_limits
+    posts = Post.all
+
+    assert posts.many?
+    assert ! posts.limit(1).many?
+  end
+
+  def test_build
+    posts = Post.all
+
+    post = posts.new
+    assert_kind_of Post, post
+  end
+
+  def test_scoped_build
+    posts = Post.where(:title => 'You told a lie')
+
+    post = posts.new
+    assert_kind_of Post, post
+    assert_equal 'You told a lie', post.title
+  end
+
+  def test_create
+    birds = Bird.all
+
+    sparrow = birds.create
+    assert_kind_of Bird, sparrow
+    assert !sparrow.persisted?
+
+    hen = birds.where(:name => 'hen').create
+    assert hen.persisted?
+    assert_equal 'hen', hen.name
+  end
+
+  def test_create_bang
+    birds = Bird.all
+
+    assert_raises(ActiveRecord::RecordInvalid) { birds.create! }
+
+    hen = birds.where(:name => 'hen').create!
+    assert_kind_of Bird, hen
+    assert hen.persisted?
+    assert_equal 'hen', hen.name
+  end
+
+  def test_first_or_create
+    parrot = Bird.where(:color => 'green').first_or_create(:name => 'parrot')
+    assert_kind_of Bird, parrot
+    assert parrot.persisted?
+    assert_equal 'parrot', parrot.name
+    assert_equal 'green', parrot.color
+
+    same_parrot = Bird.where(:color => 'green').first_or_create(:name => 'parakeet')
+    assert_kind_of Bird, same_parrot
+    assert same_parrot.persisted?
+    assert_equal parrot, same_parrot
+  end
+
+  def test_first_or_create_with_no_parameters
+    parrot = Bird.where(:color => 'green').first_or_create
+    assert_kind_of Bird, parrot
+    assert !parrot.persisted?
+    assert_equal 'green', parrot.color
+  end
+
+  def test_first_or_create_with_block
+    parrot = Bird.where(:color => 'green').first_or_create { |bird| bird.name = 'parrot' }
+    assert_kind_of Bird, parrot
+    assert parrot.persisted?
+    assert_equal 'green', parrot.color
+    assert_equal 'parrot', parrot.name
+
+    same_parrot = Bird.where(:color => 'green').first_or_create { |bird| bird.name = 'parakeet' }
+    assert_equal parrot, same_parrot
+  end
+
+  def test_first_or_create_with_array
+    several_green_birds = Bird.where(:color => 'green').first_or_create([{:name => 'parrot'}, {:name => 'parakeet'}])
+    assert_kind_of Array, several_green_birds
+    several_green_birds.each { |bird| assert bird.persisted? }
+
+    same_parrot = Bird.where(:color => 'green').first_or_create([{:name => 'hummingbird'}, {:name => 'macaw'}])
+    assert_kind_of Bird, same_parrot
+    assert_equal several_green_birds.first, same_parrot
+  end
+
+  def test_first_or_create_bang_with_valid_options
+    parrot = Bird.where(:color => 'green').first_or_create!(:name => 'parrot')
+    assert_kind_of Bird, parrot
+    assert parrot.persisted?
+    assert_equal 'parrot', parrot.name
+    assert_equal 'green', parrot.color
+
+    same_parrot = Bird.where(:color => 'green').first_or_create!(:name => 'parakeet')
+    assert_kind_of Bird, same_parrot
+    assert same_parrot.persisted?
+    assert_equal parrot, same_parrot
+  end
+
+  def test_first_or_create_bang_with_invalid_options
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create!(:pirate_id => 1) }
+  end
+
+  def test_first_or_create_bang_with_no_parameters
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create! }
+  end
+
+  def test_first_or_create_bang_with_valid_block
+    parrot = Bird.where(:color => 'green').first_or_create! { |bird| bird.name = 'parrot' }
+    assert_kind_of Bird, parrot
+    assert parrot.persisted?
+    assert_equal 'green', parrot.color
+    assert_equal 'parrot', parrot.name
+
+    same_parrot = Bird.where(:color => 'green').first_or_create! { |bird| bird.name = 'parakeet' }
+    assert_equal parrot, same_parrot
+  end
+
+  def test_first_or_create_bang_with_invalid_block
+    assert_raise(ActiveRecord::RecordInvalid) do
+      Bird.where(:color => 'green').first_or_create! { |bird| bird.pirate_id = 1 }
+    end
+  end
+
+  def test_first_or_create_with_valid_array
+    several_green_birds = Bird.where(:color => 'green').first_or_create!([{:name => 'parrot'}, {:name => 'parakeet'}])
+    assert_kind_of Array, several_green_birds
+    several_green_birds.each { |bird| assert bird.persisted? }
+
+    same_parrot = Bird.where(:color => 'green').first_or_create!([{:name => 'hummingbird'}, {:name => 'macaw'}])
+    assert_kind_of Bird, same_parrot
+    assert_equal several_green_birds.first, same_parrot
+  end
+
+  def test_first_or_create_with_invalid_array
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create!([ {:name => 'parrot'}, {:pirate_id => 1} ]) }
+  end
+
+  def test_first_or_initialize
+    parrot = Bird.where(:color => 'green').first_or_initialize(:name => 'parrot')
+    assert_kind_of Bird, parrot
+    assert !parrot.persisted?
+    assert parrot.valid?
+    assert parrot.new_record?
+    assert_equal 'parrot', parrot.name
+    assert_equal 'green', parrot.color
+  end
+
+  def test_first_or_initialize_with_no_parameters
+    parrot = Bird.where(:color => 'green').first_or_initialize
+    assert_kind_of Bird, parrot
+    assert !parrot.persisted?
+    assert !parrot.valid?
+    assert parrot.new_record?
+    assert_equal 'green', parrot.color
+  end
+
+  def test_first_or_initialize_with_block
+    parrot = Bird.where(:color => 'green').first_or_initialize { |bird| bird.name = 'parrot' }
+    assert_kind_of Bird, parrot
+    assert !parrot.persisted?
+    assert parrot.valid?
+    assert parrot.new_record?
+    assert_equal 'green', parrot.color
+    assert_equal 'parrot', parrot.name
+  end
+
+  def test_find_or_create_by
+    assert_nil Bird.find_by(name: 'bob')
+
+    bird = Bird.find_or_create_by(name: 'bob')
+    assert bird.persisted?
+
+    assert_equal bird, Bird.find_or_create_by(name: 'bob')
+  end
+
+  def test_find_or_create_by_with_create_with
+    assert_nil Bird.find_by(name: 'bob')
+
+    bird = Bird.create_with(color: 'green').find_or_create_by(name: 'bob')
+    assert bird.persisted?
+    assert_equal 'green', bird.color
+
+    assert_equal bird, Bird.create_with(color: 'blue').find_or_create_by(name: 'bob')
+  end
+
+  def test_find_or_create_by!
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.find_or_create_by!(color: 'green') }
+  end
+
+  def test_find_or_initialize_by
+    assert_nil Bird.find_by(name: 'bob')
+
+    bird = Bird.find_or_initialize_by(name: 'bob')
+    assert bird.new_record?
+    bird.save!
+
+    assert_equal bird, Bird.find_or_initialize_by(name: 'bob')
+  end
+
+  def test_explicit_create_scope
+    hens = Bird.where(:name => 'hen')
+    assert_equal 'hen', hens.new.name
+
+    hens = hens.create_with(:name => 'cock')
+    assert_equal 'cock', hens.new.name
+  end
+
+  def test_except
+    relation = Post.where(:author_id => 1).order('id ASC').limit(1)
+    assert_equal [posts(:welcome)], relation.to_a
+
+    author_posts = relation.except(:order, :limit)
+    assert_equal Post.where(:author_id => 1).to_a, author_posts.to_a
+
+    all_posts = relation.except(:where, :order, :limit)
+    assert_equal Post.all, all_posts
+  end
+
+  def test_only
+    relation = Post.where(:author_id => 1).order('id ASC').limit(1)
+    assert_equal [posts(:welcome)], relation.to_a
+
+    author_posts = relation.only(:where)
+    assert_equal Post.where(:author_id => 1).to_a, author_posts.to_a
+
+    all_posts = relation.only(:limit)
+    assert_equal Post.limit(1).to_a.first, all_posts.first
+  end
+
+  def test_anonymous_extension
+    relation = Post.where(:author_id => 1).order('id ASC').extending do
+      def author
+        'lifo'
+      end
+    end
+
+    assert_equal "lifo", relation.author
+    assert_equal "lifo", relation.limit(1).author
+  end
+
+  def test_named_extension
+    relation = Post.where(:author_id => 1).order('id ASC').extending(Post::NamedExtension)
+    assert_equal "lifo", relation.author
+    assert_equal "lifo", relation.limit(1).author
+  end
+
+  def test_order_by_relation_attribute
+    assert_equal Post.order(Post.arel_table[:title]).to_a, Post.order("title").to_a
+  end
+
+  def test_default_scope_order_with_scope_order
+    assert_equal 'zyke', CoolCar.order_using_new_style.limit(1).first.name
+    assert_equal 'zyke', FastCar.order_using_new_style.limit(1).first.name
+  end
+
+  def test_order_using_scoping
+    car1 = CoolCar.order('id DESC').scoping do
+      CoolCar.all.merge!(order: 'id asc').first
+    end
+    assert_equal 'zyke', car1.name
+
+    car2 = FastCar.order('id DESC').scoping do
+      FastCar.all.merge!(order: 'id asc').first
+    end
+    assert_equal 'zyke', car2.name
+  end
+
+  def test_unscoped_block_style
+    assert_equal 'honda', CoolCar.unscoped { CoolCar.order_using_new_style.limit(1).first.name}
+    assert_equal 'honda', FastCar.unscoped { FastCar.order_using_new_style.limit(1).first.name}
+  end
+
+  def test_intersection_with_array
+    relation = Author.where(:name => "David")
+    rails_author = relation.first
+
+    assert_equal [rails_author], [rails_author] & relation
+    assert_equal [rails_author], relation & [rails_author]
+  end
+
+  def test_primary_key
+    assert_equal "id", Post.all.primary_key
+  end
+
+  def test_disable_implicit_join_references_is_deprecated
+    assert_deprecated do
+      ActiveRecord::Base.disable_implicit_join_references = true
+    end
+  end
+
+  def test_ordering_with_extra_spaces
+    assert_equal authors(:david), Author.order('id DESC , name DESC').last
+  end
+
+  def test_update_all_with_blank_argument
+    assert_raises(ArgumentError) { Comment.update_all({}) }
+  end
+
+  def test_update_all_with_joins
+    comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id)
+    count    = comments.count
+
+    assert_equal count, comments.update_all(:post_id => posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:greetings).post
+  end
+
+  def test_update_all_with_joins_and_limit
+    comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id).limit(1)
+    assert_equal 1, comments.update_all(:post_id => posts(:thinking).id)
+  end
+
+  def test_update_all_with_joins_and_limit_and_order
+    comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id).order('comments.id').limit(1)
+    assert_equal 1, comments.update_all(:post_id => posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:greetings).post
+    assert_equal posts(:welcome),  comments(:more_greetings).post
+  end
+
+  def test_update_all_with_joins_and_offset
+    all_comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id)
+    count        = all_comments.count
+    comments     = all_comments.offset(1)
+
+    assert_equal count - 1, comments.update_all(:post_id => posts(:thinking).id)
+  end
+
+  def test_update_all_with_joins_and_offset_and_order
+    all_comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id).order('posts.id', 'comments.id')
+    count        = all_comments.count
+    comments     = all_comments.offset(1)
+
+    assert_equal count - 1, comments.update_all(:post_id => posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:more_greetings).post
+    assert_equal posts(:welcome),  comments(:greetings).post
+  end
+
+  def test_distinct
+    tag1 = Tag.create(:name => 'Foo')
+    tag2 = Tag.create(:name => 'Foo')
+
+    query = Tag.select(:name).where(:id => [tag1.id, tag2.id])
+
+    assert_equal ['Foo', 'Foo'], query.map(&:name)
+    assert_sql(/DISTINCT/) do
+      assert_equal ['Foo'], query.distinct.map(&:name)
+      assert_equal ['Foo'], query.uniq.map(&:name)
+    end
+    assert_sql(/DISTINCT/) do
+      assert_equal ['Foo'], query.distinct(true).map(&:name)
+      assert_equal ['Foo'], query.uniq(true).map(&:name)
+    end
+    assert_equal ['Foo', 'Foo'], query.distinct(true).distinct(false).map(&:name)
+    assert_equal ['Foo', 'Foo'], query.uniq(true).uniq(false).map(&:name)
+  end
+
+  def test_doesnt_add_having_values_if_options_are_blank
+    scope = Post.having('')
+    assert_equal [], scope.having_values
+
+    scope = Post.having([])
+    assert_equal [], scope.having_values
+  end
+
+  def test_references_triggers_eager_loading
+    scope = Post.includes(:comments)
+    assert !scope.eager_loading?
+    assert scope.references(:comments).eager_loading?
+  end
+
+  def test_references_doesnt_trigger_eager_loading_if_reference_not_included
+    scope = Post.references(:comments)
+    assert !scope.eager_loading?
+  end
+
+  def test_automatically_added_where_references
+    scope = Post.where(:comments => { :body => "Bla" })
+    assert_equal ['comments'], scope.references_values
+
+    scope = Post.where('comments.body' => 'Bla')
+    assert_equal ['comments'], scope.references_values
+  end
+
+  def test_automatically_added_where_not_references
+    scope = Post.where.not(comments: { body: "Bla" })
+    assert_equal ['comments'], scope.references_values
+
+    scope = Post.where.not('comments.body' => 'Bla')
+    assert_equal ['comments'], scope.references_values
+  end
+
+  def test_automatically_added_having_references
+    scope = Post.having(:comments => { :body => "Bla" })
+    assert_equal ['comments'], scope.references_values
+
+    scope = Post.having('comments.body' => 'Bla')
+    assert_equal ['comments'], scope.references_values
+  end
+
+  def test_automatically_added_order_references
+    scope = Post.order('comments.body')
+    assert_equal ['comments'], scope.references_values
+
+    scope = Post.order('comments.body', 'yaks.body')
+    assert_equal ['comments', 'yaks'], scope.references_values
+
+    # Don't infer yaks, let's not go down that road again...
+    scope = Post.order('comments.body, yaks.body')
+    assert_equal ['comments'], scope.references_values
+
+    scope = Post.order('comments.body asc')
+    assert_equal ['comments'], scope.references_values
+
+    scope = Post.order('foo(comments.body)')
+    assert_equal [], scope.references_values
+  end
+
+  def test_automatically_added_reorder_references
+    scope = Post.reorder('comments.body')
+    assert_equal %w(comments), scope.references_values
+
+    scope = Post.reorder('comments.body', 'yaks.body')
+    assert_equal %w(comments yaks), scope.references_values
+
+    # Don't infer yaks, let's not go down that road again...
+    scope = Post.reorder('comments.body, yaks.body')
+    assert_equal %w(comments), scope.references_values
+
+    scope = Post.reorder('comments.body asc')
+    assert_equal %w(comments), scope.references_values
+
+    scope = Post.reorder('foo(comments.body)')
+    assert_equal [], scope.references_values
+  end
+
+  def test_order_with_reorder_nil_removes_the_order
+    relation = Post.order(:title).reorder(nil)
+
+    assert_nil relation.order_values.first
+  end
+
+  def test_reverse_order_with_reorder_nil_removes_the_order
+    relation = Post.order(:title).reverse_order.reorder(nil)
+
+    assert_nil relation.order_values.first
+  end
+
+  def test_presence
+    topics = Topic.all
+
+    # the first query is triggered because there are no topics yet.
+    assert_queries(1) { assert topics.present? }
+
+    # checking if there are topics is used before you actually display them,
+    # thus it shouldn't invoke an extra count query.
+    assert_no_queries { assert topics.present? }
+    assert_no_queries { assert !topics.blank? }
+
+    # shows count of topics and loops after loading the query should not trigger extra queries either.
+    assert_no_queries { topics.size }
+    assert_no_queries { topics.length }
+    assert_no_queries { topics.each }
+
+    # count always trigger the COUNT query.
+    assert_queries(1) { topics.count }
+
+    assert topics.loaded?
+  end
+
+  test "find_by with hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by(author_id: 2)
+  end
+
+  test "find_by with non-hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by("author_id = 2")
+  end
+
+  test "find_by with multi-arg conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by('author_id = ?', 2)
+  end
+
+  test "find_by returns nil if the record is missing" do
+    assert_equal nil, Post.all.find_by("1 = 0")
+  end
+
+  test "find_by doesn't have implicit ordering" do
+    assert_sql(/^((?!ORDER).)*$/) { Post.find_by(author_id: 2) }
+  end
+
+  test "find_by! with hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by!(author_id: 2)
+  end
+
+  test "find_by! with non-hash conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by!("author_id = 2")
+  end
+
+  test "find_by! with multi-arg conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.order(:id).find_by!('author_id = ?', 2)
+  end
+
+  test "find_by! doesn't have implicit ordering" do
+    assert_sql(/^((?!ORDER).)*$/) { Post.find_by!(author_id: 2) }
+  end
+
+  test "find_by! raises RecordNotFound if the record is missing" do
+    assert_raises(ActiveRecord::RecordNotFound) do
+      Post.all.find_by!("1 = 0")
+    end
+  end
+
+  test "loaded relations cannot be mutated by multi value methods" do
+    relation = Post.all
+    relation.to_a
+
+    assert_raises(ActiveRecord::ImmutableRelation) do
+      relation.where! 'foo'
+    end
+  end
+
+  test "loaded relations cannot be mutated by single value methods" do
+    relation = Post.all
+    relation.to_a
+
+    assert_raises(ActiveRecord::ImmutableRelation) do
+      relation.limit! 5
+    end
+  end
+
+  test "loaded relations cannot be mutated by merge!" do
+    relation = Post.all
+    relation.to_a
+
+    assert_raises(ActiveRecord::ImmutableRelation) do
+      relation.merge! where: 'foo'
+    end
+  end
+
+  test "loaded relations cannot be mutated by extending!" do
+    relation = Post.all
+    relation.to_a
+
+    assert_raises(ActiveRecord::ImmutableRelation) do
+      relation.extending! Module.new
+    end
+  end
+
+  test "relations show the records in #inspect" do
+    relation = Post.limit(2)
+    assert_equal "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>", relation.inspect
+  end
+
+  test "relations limit the records in #inspect at 10" do
+    relation = Post.limit(11)
+    assert_equal "#<ActiveRecord::Relation [#{Post.limit(10).map(&:inspect).join(', ')}, ...]>", relation.inspect
+  end
+
+  test "already-loaded relations don't perform a new query in #inspect" do
+    relation = Post.limit(2)
+    relation.to_a
+
+    expected = "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>"
+
+    assert_no_queries do
+      assert_equal expected, relation.inspect
+    end
+  end
+
+  test 'using a custom table affects the wheres' do
+    table_alias = Post.arel_table.alias('omg_posts')
+
+    relation = ActiveRecord::Relation.new Post, table_alias
+    relation.where!(:foo => "bar")
+
+    node = relation.arel.constraints.first.grep(Arel::Attributes::Attribute).first
+    assert_equal table_alias, node.relation
+  end
+
+  test '#load' do
+    relation = Post.all
+    assert_queries(1) do
+      assert_equal relation, relation.load
+    end
+    assert_no_queries { relation.to_a }
+  end
+
+  test 'group with select and includes' do
+    authors_count = Post.select('author_id, COUNT(author_id) AS num_posts').
+      group('author_id').order('author_id').includes(:author).to_a
+
+    assert_no_queries do
+      result = authors_count.map do |post|
+        [post.num_posts, post.author.try(:name)]
+      end
+
+      expected = [[1, nil], [5, "David"], [3, "Mary"], [2, "Bob"]]
+      assert_equal expected, result
+    end
+  end
+
+  test "joins with select" do
+    posts = Post.joins(:author).select("id", "authors.author_address_id").order("posts.id").limit(3)
+    assert_equal [1, 2, 4], posts.map(&:id)
+    assert_equal [1, 1, 1], posts.map(&:author_address_id)
+  end
+
+  test "delegations do not leak to other classes" do
+    Topic.all.by_lifo
+    assert Topic.all.class.method_defined?(:by_lifo)
+    assert !Post.all.respond_to?(:by_lifo)
+  end
+
+  def test_unscope_removes_binds
+    left  = Post.where(id: Arel::Nodes::BindParam.new('?'))
+    column = Post.columns_hash['id']
+    left.bind_values += [[column, 20]]
+
+    relation = left.unscope(where: :id)
+    assert_equal [], relation.bind_values
+  end
+
+  def test_merging_removes_rhs_bind_parameters
+    left  = Post.where(id: 20)
+    right   = Post.where(id: [1,2,3,4])
+
+    merged = left.merge(right)
+    assert_equal [], merged.bind_values
+  end
+
+  def test_merging_keeps_lhs_bind_parameters
+    column = Post.columns_hash['id']
+    binds = [[column, 20]]
+
+    right  = Post.where(id: 20)
+    left   = Post.where(id: 10)
+
+    merged = left.merge(right)
+    assert_equal binds, merged.bind_values
+  end
+
+  def test_merging_reorders_bind_params
+    post  = Post.first
+    right = Post.where(id: post.id)
+    left  = Post.where(title: post.title)
+
+    merged = left.merge(right)
+    assert_equal post, merged.first
+  end
+
+  def test_relation_join_method
+    assert_equal 'Thank you for the welcome,Thank you again for the welcome', Post.first.comments.join(",")
+  end
+end
diff --git a/activerecord/test/cases/reload_models_test.rb b/activerecord/test/cases/reload_models_test.rb
new file mode 100644
index 0000000000..0d16a3526f
--- /dev/null
+++ b/activerecord/test/cases/reload_models_test.rb
@@ -0,0 +1,22 @@
+require "cases/helper"
+require 'models/owner'
+require 'models/pet'
+
+class ReloadModelsTest < ActiveRecord::TestCase
+  fixtures :pets
+
+  def test_has_one_with_reload
+    pet = Pet.find_by_name('parrot')
+    pet.owner = Owner.find_by_name('ashley')
+
+    # Reload the class Owner, simulating auto-reloading of model classes in a
+    # development environment. Note that meanwhile the class Pet is not
+    # reloaded, simulating a class that is present in a plugin.
+    Object.class_eval { remove_const :Owner }
+    Kernel.load(File.expand_path(File.join(File.dirname(__FILE__), "../models/owner.rb")))
+
+    pet = Pet.find_by_name('parrot')
+    pet.owner = Owner.find_by_name('ashley')
+    assert_equal pet.owner, Owner.find_by_name('ashley')
+  end
+end
diff --git a/activerecord/test/cases/result_test.rb b/activerecord/test/cases/result_test.rb
new file mode 100644
index 0000000000..d6decafad9
--- /dev/null
+++ b/activerecord/test/cases/result_test.rb
@@ -0,0 +1,76 @@
+require "cases/helper"
+
+module ActiveRecord
+  class ResultTest < ActiveRecord::TestCase
+    def result
+      Result.new(['col_1', 'col_2'], [
+        ['row 1 col 1', 'row 1 col 2'],
+        ['row 2 col 1', 'row 2 col 2'],
+        ['row 3 col 1', 'row 3 col 2'],
+      ])
+    end
+
+    test "to_hash returns row_hashes" do
+      assert_equal [
+        {'col_1' => 'row 1 col 1', 'col_2' => 'row 1 col 2'},
+        {'col_1' => 'row 2 col 1', 'col_2' => 'row 2 col 2'},
+        {'col_1' => 'row 3 col 1', 'col_2' => 'row 3 col 2'},
+      ], result.to_hash
+    end
+
+    test "each with block returns row hashes" do
+      result.each do |row|
+        assert_equal ['col_1', 'col_2'], row.keys
+      end
+    end
+
+    test "each without block returns an enumerator" do
+      result.each.with_index do |row, index|
+        assert_equal ['col_1', 'col_2'], row.keys
+        assert_kind_of Integer, index
+      end
+    end
+
+    if Enumerator.method_defined? :size
+      test "each without block returns a sized enumerator" do
+        assert_equal 3, result.each.size
+      end
+    end
+
+    test "cast_values returns rows after type casting" do
+      values = [["1.1", "2.2"], ["3.3", "4.4"]]
+      columns = ["col1", "col2"]
+      types = { "col1" => Type::Integer.new, "col2" => Type::Float.new }
+      result = Result.new(columns, values, types)
+
+      assert_equal [[1, 2.2], [3, 4.4]], result.cast_values
+    end
+
+    test "cast_values uses identity type for unknown types" do
+      values = [["1.1", "2.2"], ["3.3", "4.4"]]
+      columns = ["col1", "col2"]
+      types = { "col1" => Type::Integer.new }
+      result = Result.new(columns, values, types)
+
+      assert_equal [[1, "2.2"], [3, "4.4"]], result.cast_values
+    end
+
+    test "cast_values returns single dimensional array if single column" do
+      values = [["1.1"], ["3.3"]]
+      columns = ["col1"]
+      types = { "col1" => Type::Integer.new }
+      result = Result.new(columns, values, types)
+
+      assert_equal [1, 3], result.cast_values
+    end
+
+    test "cast_values can receive types to use instead" do
+      values = [["1.1", "2.2"], ["3.3", "4.4"]]
+      columns = ["col1", "col2"]
+      types = { "col1" => Type::Integer.new, "col2" => Type::Float.new }
+      result = Result.new(columns, values, types)
+
+      assert_equal [[1.1, 2.2], [3.3, 4.4]], result.cast_values("col1" => Type::Float.new)
+    end
+  end
+end
diff --git a/activerecord/test/cases/sanitize_test.rb b/activerecord/test/cases/sanitize_test.rb
new file mode 100644
index 0000000000..dca85fb5eb
--- /dev/null
+++ b/activerecord/test/cases/sanitize_test.rb
@@ -0,0 +1,81 @@
+require "cases/helper"
+require 'models/binary'
+require 'models/author'
+require 'models/post'
+
+class SanitizeTest < ActiveRecord::TestCase
+  def setup
+  end
+
+  def test_sanitize_sql_hash_handles_associations
+    quoted_bambi = ActiveRecord::Base.connection.quote("Bambi")
+    quoted_column_name = ActiveRecord::Base.connection.quote_column_name("name")
+    quoted_table_name = ActiveRecord::Base.connection.quote_table_name("adorable_animals")
+    expected_value = "#{quoted_table_name}.#{quoted_column_name} = #{quoted_bambi}"
+
+    assert_equal expected_value, Binary.send(:sanitize_sql_hash, {adorable_animals: {name: 'Bambi'}})
+  end
+
+  def test_sanitize_sql_array_handles_string_interpolation
+    quoted_bambi = ActiveRecord::Base.connection.quote_string("Bambi")
+    assert_equal "name=#{quoted_bambi}", Binary.send(:sanitize_sql_array, ["name=%s", "Bambi"])
+    assert_equal "name=#{quoted_bambi}", Binary.send(:sanitize_sql_array, ["name=%s", "Bambi".mb_chars])
+    quoted_bambi_and_thumper = ActiveRecord::Base.connection.quote_string("Bambi\nand\nThumper")
+    assert_equal "name=#{quoted_bambi_and_thumper}",Binary.send(:sanitize_sql_array, ["name=%s", "Bambi\nand\nThumper"])
+    assert_equal "name=#{quoted_bambi_and_thumper}",Binary.send(:sanitize_sql_array, ["name=%s", "Bambi\nand\nThumper".mb_chars])
+  end
+
+  def test_sanitize_sql_array_handles_bind_variables
+    quoted_bambi = ActiveRecord::Base.connection.quote("Bambi")
+    assert_equal "name=#{quoted_bambi}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi"])
+    assert_equal "name=#{quoted_bambi}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi".mb_chars])
+    quoted_bambi_and_thumper = ActiveRecord::Base.connection.quote("Bambi\nand\nThumper")
+    assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi\nand\nThumper"])
+    assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi\nand\nThumper".mb_chars])
+  end
+
+  def test_sanitize_sql_array_handles_relations
+    david = Author.create!(name: 'David')
+    david_posts = david.posts.select(:id)
+
+    sub_query_pattern = /\(\bselect\b.*?\bwhere\b.*?\)/i
+
+    select_author_sql = Post.send(:sanitize_sql_array, ['id in (?)', david_posts])
+    assert_match(sub_query_pattern, select_author_sql, 'should sanitize `Relation` as subquery for bind variables')
+
+    select_author_sql = Post.send(:sanitize_sql_array, ['id in (:post_ids)', post_ids: david_posts])
+    assert_match(sub_query_pattern, select_author_sql, 'should sanitize `Relation` as subquery for named bind variables')
+  end
+
+  def test_sanitize_sql_array_handles_empty_statement
+    select_author_sql = Post.send(:sanitize_sql_array, [''])
+    assert_equal('', select_author_sql)
+  end
+
+  def test_sanitize_sql_like
+    assert_equal '100\%', Binary.send(:sanitize_sql_like, '100%')
+    assert_equal 'snake\_cased\_string', Binary.send(:sanitize_sql_like, 'snake_cased_string')
+    assert_equal 'C:\\\\Programs\\\\MsPaint', Binary.send(:sanitize_sql_like, 'C:\\Programs\\MsPaint')
+    assert_equal 'normal string 42', Binary.send(:sanitize_sql_like, 'normal string 42')
+  end
+
+  def test_sanitize_sql_like_with_custom_escape_character
+    assert_equal '100!%', Binary.send(:sanitize_sql_like, '100%', '!')
+    assert_equal 'snake!_cased!_string', Binary.send(:sanitize_sql_like, 'snake_cased_string', '!')
+    assert_equal 'great!!', Binary.send(:sanitize_sql_like, 'great!', '!')
+    assert_equal 'C:\\Programs\\MsPaint', Binary.send(:sanitize_sql_like, 'C:\\Programs\\MsPaint', '!')
+    assert_equal 'normal string 42', Binary.send(:sanitize_sql_like, 'normal string 42', '!')
+  end
+
+  def test_sanitize_sql_like_example_use_case
+    searchable_post = Class.new(Post) do
+      def self.search(term)
+        where("title LIKE ?", sanitize_sql_like(term, '!'))
+      end
+    end
+
+    assert_sql(/LIKE '20!% !_reduction!_!!'/) do
+      searchable_post.search("20% _reduction_!").to_a
+    end
+  end
+end
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
new file mode 100644
index 0000000000..4e71d04bc0
--- /dev/null
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -0,0 +1,451 @@
+require "cases/helper"
+require 'support/schema_dumping_helper'
+
+class SchemaDumperTest < ActiveRecord::TestCase
+  setup do
+    ActiveRecord::SchemaMigration.create_table
+  end
+
+  def standard_dump
+    @stream = StringIO.new
+    ActiveRecord::SchemaDumper.ignore_tables = []
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, @stream)
+    @stream.string
+  end
+
+  def test_dump_schema_information_outputs_lexically_ordered_versions
+    versions = %w{ 20100101010101 20100201010101 20100301010101 }
+    versions.reverse.each do |v|
+      ActiveRecord::SchemaMigration.create!(:version => v)
+    end
+
+    schema_info = ActiveRecord::Base.connection.dump_schema_information
+    assert_match(/20100201010101.*20100301010101/m, schema_info)
+  end
+
+  def test_magic_comment
+    output = standard_dump
+    assert_match "# encoding: #{@stream.external_encoding.name}", output
+  end
+
+  def test_schema_dump
+    output = standard_dump
+    assert_match %r{create_table "accounts"}, output
+    assert_match %r{create_table "authors"}, output
+    assert_no_match %r{create_table "schema_migrations"}, output
+  end
+
+  def test_schema_dump_excludes_sqlite_sequence
+    output = standard_dump
+    assert_no_match %r{create_table "sqlite_sequence"}, output
+  end
+
+  def test_schema_dump_includes_camelcase_table_name
+    output = standard_dump
+    assert_match %r{create_table "CamelCase"}, output
+  end
+
+  def assert_line_up(lines, pattern, required = false)
+    return assert(true) if lines.empty?
+    matches = lines.map { |line| line.match(pattern) }
+    assert matches.all? if required
+    matches.compact!
+    return assert(true) if matches.empty?
+    assert_equal 1, matches.map{ |match| match.offset(0).first }.uniq.length
+  end
+
+  def column_definition_lines(output = standard_dump)
+    output.scan(/^( *)create_table.*?\n(.*?)^\1end/m).map{ |m| m.last.split(/\n/) }
+  end
+
+  def test_types_line_up
+    column_definition_lines.each do |column_set|
+      next if column_set.empty?
+
+      lengths = column_set.map do |column|
+        if match = column.match(/t\.(?:integer|decimal|float|datetime|timestamp|time|date|text|binary|string|boolean|uuid|point)\s+"/)
+          match[0].length
+        end
+      end
+
+      assert_equal 1, lengths.uniq.length
+    end
+  end
+
+  def test_arguments_line_up
+    column_definition_lines.each do |column_set|
+      assert_line_up(column_set, /default: /)
+      assert_line_up(column_set, /limit: /)
+      assert_line_up(column_set, /null: /)
+    end
+  end
+
+  def test_no_dump_errors
+    output = standard_dump
+    assert_no_match %r{\# Could not dump table}, output
+  end
+
+  def test_schema_dump_includes_not_null_columns
+    stream = StringIO.new
+
+    ActiveRecord::SchemaDumper.ignore_tables = [/^[^r]/]
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    output = stream.string
+    assert_match %r{null: false}, output
+  end
+
+  def test_schema_dump_includes_limit_constraint_for_integer_columns
+    stream = StringIO.new
+
+    ActiveRecord::SchemaDumper.ignore_tables = [/^(?!integer_limits)/]
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    output = stream.string
+
+    if current_adapter?(:PostgreSQLAdapter)
+      assert_match %r{c_int_1.*limit: 2}, output
+      assert_match %r{c_int_2.*limit: 2}, output
+
+      # int 3 is 4 bytes in postgresql
+      assert_match %r{c_int_3.*}, output
+      assert_no_match %r{c_int_3.*limit:}, output
+
+      assert_match %r{c_int_4.*}, output
+      assert_no_match %r{c_int_4.*limit:}, output
+    elsif current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+      assert_match %r{c_int_1.*limit: 1}, output
+      assert_match %r{c_int_2.*limit: 2}, output
+      assert_match %r{c_int_3.*limit: 3}, output
+
+      assert_match %r{c_int_4.*}, output
+      assert_no_match %r{c_int_4.*:limit}, output
+    elsif current_adapter?(:SQLite3Adapter)
+      assert_match %r{c_int_1.*limit: 1}, output
+      assert_match %r{c_int_2.*limit: 2}, output
+      assert_match %r{c_int_3.*limit: 3}, output
+      assert_match %r{c_int_4.*limit: 4}, output
+    end
+    assert_match %r{c_int_without_limit.*}, output
+    assert_no_match %r{c_int_without_limit.*limit:}, output
+
+    if current_adapter?(:SQLite3Adapter)
+      assert_match %r{c_int_5.*limit: 5}, output
+      assert_match %r{c_int_6.*limit: 6}, output
+      assert_match %r{c_int_7.*limit: 7}, output
+      assert_match %r{c_int_8.*limit: 8}, output
+    elsif current_adapter?(:OracleAdapter)
+      assert_match %r{c_int_5.*limit: 5}, output
+      assert_match %r{c_int_6.*limit: 6}, output
+      assert_match %r{c_int_7.*limit: 7}, output
+      assert_match %r{c_int_8.*limit: 8}, output
+    else
+      assert_match %r{c_int_5.*limit: 8}, output
+      assert_match %r{c_int_6.*limit: 8}, output
+      assert_match %r{c_int_7.*limit: 8}, output
+      assert_match %r{c_int_8.*limit: 8}, output
+    end
+  end
+
+  def test_schema_dump_with_string_ignored_table
+    stream = StringIO.new
+
+    ActiveRecord::SchemaDumper.ignore_tables = ['accounts']
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    output = stream.string
+    assert_no_match %r{create_table "accounts"}, output
+    assert_match %r{create_table "authors"}, output
+    assert_no_match %r{create_table "schema_migrations"}, output
+  end
+
+  def test_schema_dump_with_regexp_ignored_table
+    stream = StringIO.new
+
+    ActiveRecord::SchemaDumper.ignore_tables = [/^account/]
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    output = stream.string
+    assert_no_match %r{create_table "accounts"}, output
+    assert_match %r{create_table "authors"}, output
+    assert_no_match %r{create_table "schema_migrations"}, output
+  end
+
+  def test_schema_dump_illegal_ignored_table_value
+    stream = StringIO.new
+    ActiveRecord::SchemaDumper.ignore_tables = [5]
+    assert_raise(StandardError) do
+      ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    end
+  end
+
+  def test_schema_dumps_index_columns_in_right_order
+    index_definition = standard_dump.split(/\n/).grep(/add_index.*companies/).first.strip
+    if current_adapter?(:MysqlAdapter, :Mysql2Adapter, :PostgreSQLAdapter)
+      assert_equal 'add_index "companies", ["firm_id", "type", "rating"], name: "company_index", using: :btree', index_definition
+    else
+      assert_equal 'add_index "companies", ["firm_id", "type", "rating"], name: "company_index"', index_definition
+    end
+  end
+
+  def test_schema_dumps_partial_indices
+    index_definition = standard_dump.split(/\n/).grep(/add_index.*company_partial_index/).first.strip
+    if current_adapter?(:PostgreSQLAdapter)
+      assert_equal 'add_index "companies", ["firm_id", "type"], name: "company_partial_index", where: "(rating > 10)", using: :btree', index_definition
+    elsif current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+      assert_equal 'add_index "companies", ["firm_id", "type"], name: "company_partial_index", using: :btree', index_definition
+    elsif current_adapter?(:SQLite3Adapter) && ActiveRecord::Base.connection.supports_partial_index?
+      assert_equal 'add_index "companies", ["firm_id", "type"], name: "company_partial_index", where: "rating > 10"', index_definition
+    else
+      assert_equal 'add_index "companies", ["firm_id", "type"], name: "company_partial_index"', index_definition
+    end
+  end
+
+  def test_schema_dump_should_honor_nonstandard_primary_keys
+    output = standard_dump
+    match = output.match(%r{create_table "movies"(.*)do})
+    assert_not_nil(match, "nonstandardpk table not found")
+    assert_match %r(primary_key: "movieid"), match[1], "non-standard primary key not preserved"
+  end
+
+  def test_schema_dump_should_use_false_as_default
+    output = standard_dump
+    assert_match %r{t\.boolean\s+"has_fun",.+default: false}, output
+  end
+
+  if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+    def test_schema_dump_should_not_add_default_value_for_mysql_text_field
+      output = standard_dump
+      assert_match %r{t.text\s+"body",\s+null: false$}, output
+    end
+
+    def test_schema_dump_includes_length_for_mysql_binary_fields
+      output = standard_dump
+      assert_match %r{t.binary\s+"var_binary",\s+limit: 255$}, output
+      assert_match %r{t.binary\s+"var_binary_large",\s+limit: 4095$}, output
+    end
+
+    def test_schema_dump_includes_length_for_mysql_blob_and_text_fields
+      output = standard_dump
+      assert_match %r{t.binary\s+"tiny_blob",\s+limit: 255$}, output
+      assert_match %r{t.binary\s+"normal_blob"$}, output
+      assert_match %r{t.binary\s+"medium_blob",\s+limit: 16777215$}, output
+      assert_match %r{t.binary\s+"long_blob",\s+limit: 2147483647$}, output
+      assert_match %r{t.text\s+"tiny_text",\s+limit: 255$}, output
+      assert_match %r{t.text\s+"normal_text"$}, output
+      assert_match %r{t.text\s+"medium_text",\s+limit: 16777215$}, output
+      assert_match %r{t.text\s+"long_text",\s+limit: 2147483647$}, output
+    end
+
+    def test_schema_dumps_index_type
+      output = standard_dump
+      assert_match %r{add_index "key_tests", \["awesome"\], name: "index_key_tests_on_awesome", type: :fulltext}, output
+      assert_match %r{add_index "key_tests", \["pizza"\], name: "index_key_tests_on_pizza", using: :btree}, output
+    end
+  end
+
+  def test_schema_dump_includes_decimal_options
+    stream = StringIO.new
+    ActiveRecord::SchemaDumper.ignore_tables = [/^[^n]/]
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    output = stream.string
+    assert_match %r{precision: 3,[[:space:]]+scale: 2,[[:space:]]+default: 2.78}, output
+  end
+
+  if current_adapter?(:PostgreSQLAdapter)
+    def test_schema_dump_includes_bigint_default
+      output = standard_dump
+      assert_match %r{t.integer\s+"bigint_default",\s+limit: 8,\s+default: 0}, output
+    end
+
+    if ActiveRecord::Base.connection.supports_extensions?
+      def test_schema_dump_includes_extensions
+        connection = ActiveRecord::Base.connection
+
+        connection.stubs(:extensions).returns(['hstore'])
+        output = standard_dump
+        assert_match "# These are extensions that must be enabled", output
+        assert_match %r{enable_extension "hstore"}, output
+
+        connection.stubs(:extensions).returns([])
+        output = standard_dump
+        assert_no_match "# These are extensions that must be enabled", output
+        assert_no_match %r{enable_extension}, output
+      end
+    end
+
+    def test_schema_dump_includes_xml_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_xml_data_type"} =~ output
+        assert_match %r{t.xml "data"}, output
+      end
+    end
+
+    def test_schema_dump_includes_json_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_json_data_type"} =~ output
+        assert_match %r|t.json "json_data", default: {}|, output
+      end
+    end
+
+    def test_schema_dump_includes_inet_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_network_addresses"} =~ output
+        assert_match %r{t.inet\s+"inet_address",\s+default: "192.168.1.1"}, output
+      end
+    end
+
+    def test_schema_dump_includes_cidr_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_network_addresses"} =~ output
+        assert_match %r{t.cidr\s+"cidr_address",\s+default: "192.168.1.0/24"}, output
+      end
+    end
+
+    def test_schema_dump_includes_macaddr_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_network_addresses"} =~ output
+        assert_match %r{t.macaddr\s+"mac_address",\s+default: "ff:ff:ff:ff:ff:ff"}, output
+      end
+    end
+
+    def test_schema_dump_includes_uuid_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_uuids"} =~ output
+        assert_match %r{t.uuid "guid"}, output
+      end
+    end
+
+    def test_schema_dump_includes_hstores_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_hstores"} =~ output
+        assert_match %r[t.hstore "hash_store", default: {}], output
+      end
+    end
+
+    def test_schema_dump_includes_citext_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_citext"} =~ output
+        assert_match %r[t.citext "text_citext"], output
+      end
+    end
+
+    def test_schema_dump_includes_ltrees_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_ltrees"} =~ output
+        assert_match %r[t.ltree "path"], output
+      end
+    end
+
+    def test_schema_dump_includes_arrays_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_arrays"} =~ output
+        assert_match %r[t.text\s+"nicknames",\s+array: true], output
+        assert_match %r[t.integer\s+"commission_by_quarter",\s+array: true], output
+      end
+    end
+
+    def test_schema_dump_includes_tsvector_shorthand_definition
+      output = standard_dump
+      if %r{create_table "postgresql_tsvectors"} =~ output
+        assert_match %r{t.tsvector "text_vector"}, output
+      end
+    end
+  end
+
+  def test_schema_dump_keeps_large_precision_integer_columns_as_decimal
+    output = standard_dump
+    # Oracle supports precision up to 38 and it identifies decimals with scale 0 as integers
+    if current_adapter?(:OracleAdapter)
+      assert_match %r{t.integer\s+"atoms_in_universe",\s+precision: 38}, output
+    else
+      assert_match %r{t.decimal\s+"atoms_in_universe",\s+precision: 55}, output
+    end
+  end
+
+  def test_schema_dump_keeps_id_column_when_id_is_false_and_id_column_added
+    output = standard_dump
+    match = output.match(%r{create_table "goofy_string_id"(.*)do.*\n(.*)\n})
+    assert_not_nil(match, "goofy_string_id table not found")
+    assert_match %r(id: false), match[1], "no table id not preserved"
+    assert_match %r{t.string[[:space:]]+"id",[[:space:]]+null: false$}, match[2], "non-primary key id column not preserved"
+  end
+
+  def test_schema_dump_keeps_id_false_when_id_is_false_and_unique_not_null_column_added
+    output = standard_dump
+    assert_match %r{create_table "subscribers", id: false}, output
+  end
+
+  if ActiveRecord::Base.connection.supports_foreign_keys?
+    def test_foreign_keys_are_dumped_at_the_bottom_to_circumvent_dependency_issues
+      output = standard_dump
+      assert_match(/^\s+add_foreign_key "fk_test_has_fk"[^\n]+\n\s+add_foreign_key "lessons_students"/, output)
+    end
+  end
+
+  class CreateDogMigration < ActiveRecord::Migration
+    def up
+      create_table("dog_owners") do |t|
+      end
+
+      create_table("dogs") do |t|
+        t.column :name, :string
+        t.column :owner_id, :integer
+      end
+      add_index "dogs", [:name]
+      add_foreign_key :dogs, :dog_owners, column: "owner_id" if supports_foreign_keys?
+    end
+    def down
+      drop_table("dogs")
+      drop_table("dog_owners")
+    end
+  end
+
+  def test_schema_dump_with_table_name_prefix_and_suffix
+    original, $stdout = $stdout, StringIO.new
+    ActiveRecord::Base.table_name_prefix = 'foo_'
+    ActiveRecord::Base.table_name_suffix = '_bar'
+
+    migration = CreateDogMigration.new
+    migration.migrate(:up)
+
+    output = standard_dump
+    assert_no_match %r{create_table "foo_.+_bar"}, output
+    assert_no_match %r{add_index "foo_.+_bar"}, output
+    assert_no_match %r{create_table "schema_migrations"}, output
+
+    if ActiveRecord::Base.connection.supports_foreign_keys?
+      assert_no_match %r{add_foreign_key "foo_.+_bar"}, output
+      assert_no_match %r{add_foreign_key "[^"]+", "foo_.+_bar"}, output
+    end
+  ensure
+    migration.migrate(:down)
+
+    ActiveRecord::Base.table_name_suffix = ActiveRecord::Base.table_name_prefix = ''
+    $stdout = original
+  end
+end
+
+class SchemaDumperDefaultsTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table :defaults, force: true do |t|
+      t.string   :string_with_default,   default: "Hello!"
+      t.date     :date_with_default,     default: '2014-06-05'
+      t.datetime :datetime_with_default, default: "2014-06-05 07:17:04"
+      t.time     :time_with_default,     default: "07:17:04"
+    end
+  end
+
+  teardown do
+    return unless @connection
+    @connection.execute 'DROP TABLE IF EXISTS defaults'
+  end
+
+  def test_schema_dump_defaults_with_universally_supported_types
+    output = dump_table_schema('defaults')
+
+    assert_match %r{t\.string\s+"string_with_default",\s+default: "Hello!"}, output
+    assert_match %r{t\.date\s+"date_with_default",\s+default: '2014-06-05'}, output
+    assert_match %r{t\.datetime\s+"datetime_with_default",\s+default: '2014-06-05 07:17:04'}, output
+    assert_match %r{t\.time\s+"time_with_default",\s+default: '2000-01-01 07:17:04'}, output
+  end
+end
diff --git a/activerecord/test/cases/scoping/default_scoping_test.rb b/activerecord/test/cases/scoping/default_scoping_test.rb
new file mode 100644
index 0000000000..9a4d8c6740
--- /dev/null
+++ b/activerecord/test/cases/scoping/default_scoping_test.rb
@@ -0,0 +1,416 @@
+require 'cases/helper'
+require 'models/post'
+require 'models/developer'
+
+class DefaultScopingTest < ActiveRecord::TestCase
+  fixtures :developers, :posts
+
+  def test_default_scope
+    expected = Developer.all.merge!(:order => 'salary DESC').to_a.collect { |dev| dev.salary }
+    received = DeveloperOrderedBySalary.all.collect { |dev| dev.salary }
+    assert_equal expected, received
+  end
+
+  def test_default_scope_as_class_method
+    assert_equal [developers(:david).becomes(ClassMethodDeveloperCalledDavid)], ClassMethodDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_as_class_method_referencing_scope
+    assert_equal [developers(:david).becomes(ClassMethodReferencingScopeDeveloperCalledDavid)], ClassMethodReferencingScopeDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_as_block_referencing_scope
+    assert_equal [developers(:david).becomes(LazyBlockReferencingScopeDeveloperCalledDavid)], LazyBlockReferencingScopeDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_with_lambda
+    assert_equal [developers(:david).becomes(LazyLambdaDeveloperCalledDavid)], LazyLambdaDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_with_block
+    assert_equal [developers(:david).becomes(LazyBlockDeveloperCalledDavid)], LazyBlockDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_with_callable
+    assert_equal [developers(:david).becomes(CallableDeveloperCalledDavid)], CallableDeveloperCalledDavid.all
+  end
+
+  def test_default_scope_is_unscoped_on_find
+    assert_equal 1, DeveloperCalledDavid.count
+    assert_equal 11, DeveloperCalledDavid.unscoped.count
+  end
+
+  def test_default_scope_is_unscoped_on_create
+    assert_nil DeveloperCalledJamis.unscoped.create!.name
+  end
+
+  def test_default_scope_with_conditions_string
+    assert_equal Developer.where(name: 'David').map(&:id).sort, DeveloperCalledDavid.all.map(&:id).sort
+    assert_equal nil, DeveloperCalledDavid.create!.name
+  end
+
+  def test_default_scope_with_conditions_hash
+    assert_equal Developer.where(name: 'Jamis').map(&:id).sort, DeveloperCalledJamis.all.map(&:id).sort
+    assert_equal 'Jamis', DeveloperCalledJamis.create!.name
+  end
+
+  unless in_memory_db?
+    def test_default_scoping_with_threads
+      2.times do
+        Thread.new {
+          assert DeveloperOrderedBySalary.all.to_sql.include?('salary DESC')
+          DeveloperOrderedBySalary.connection.close
+        }.join
+      end
+    end
+  end
+
+  def test_default_scope_with_inheritance
+    wheres = InheritedPoorDeveloperCalledJamis.all.where_values_hash
+    assert_equal "Jamis", wheres['name']
+    assert_equal 50000,   wheres['salary']
+  end
+
+  def test_default_scope_with_module_includes
+    wheres = ModuleIncludedPoorDeveloperCalledJamis.all.where_values_hash
+    assert_equal "Jamis", wheres['name']
+    assert_equal 50000,   wheres['salary']
+  end
+
+  def test_default_scope_with_multiple_calls
+    wheres = MultiplePoorDeveloperCalledJamis.all.where_values_hash
+    assert_equal "Jamis", wheres['name']
+    assert_equal 50000,   wheres['salary']
+  end
+
+  def test_scope_overwrites_default
+    expected = Developer.all.merge!(order: 'salary DESC, name DESC').to_a.collect { |dev| dev.name }
+    received = DeveloperOrderedBySalary.by_name.to_a.collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_reorder_overrides_default_scope_order
+    expected = Developer.order('name DESC').collect { |dev| dev.name }
+    received = DeveloperOrderedBySalary.reorder('name DESC').collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_order_after_reorder_combines_orders
+    expected = Developer.order('name DESC, id DESC').collect { |dev| [dev.name, dev.id] }
+    received = Developer.order('name ASC').reorder('name DESC').order('id DESC').collect { |dev| [dev.name, dev.id] }
+    assert_equal expected, received
+  end
+
+  def test_unscope_overrides_default_scope
+    expected = Developer.all.collect { |dev| [dev.name, dev.id] }
+    received = DeveloperCalledJamis.unscope(:where).collect { |dev| [dev.name, dev.id] }
+    assert_equal expected, received
+  end
+
+  def test_unscope_after_reordering_and_combining
+    expected = Developer.order('id DESC, name DESC').collect { |dev| [dev.name, dev.id] }
+    received = DeveloperOrderedBySalary.reorder('name DESC').unscope(:order).order('id DESC, name DESC').collect { |dev| [dev.name, dev.id] }
+    assert_equal expected, received
+
+    expected_2 = Developer.all.collect { |dev| [dev.name, dev.id] }
+    received_2 = Developer.order('id DESC, name DESC').unscope(:order).collect { |dev| [dev.name, dev.id] }
+    assert_equal expected_2, received_2
+
+    expected_3 = Developer.all.collect { |dev| [dev.name, dev.id] }
+    received_3 = Developer.reorder('name DESC').unscope(:order).collect { |dev| [dev.name, dev.id] }
+    assert_equal expected_3, received_3
+  end
+
+  def test_unscope_with_where_attributes
+    expected = Developer.order('salary DESC').collect(&:name)
+    received = DeveloperOrderedBySalary.where(name: 'David').unscope(where: :name).collect(&:name)
+    assert_equal expected, received
+
+    expected_2 = Developer.order('salary DESC').collect(&:name)
+    received_2 = DeveloperOrderedBySalary.select("id").where("name" => "Jamis").unscope({:where => :name}, :select).collect(&:name)
+    assert_equal expected_2, received_2
+
+    expected_3 = Developer.order('salary DESC').collect(&:name)
+    received_3 = DeveloperOrderedBySalary.select("id").where("name" => "Jamis").unscope(:select, :where).collect(&:name)
+    assert_equal expected_3, received_3
+
+    expected_4 = Developer.order('salary DESC').collect(&:name)
+    received_4 = DeveloperOrderedBySalary.where.not("name" => "Jamis").unscope(where: :name).collect(&:name)
+    assert_equal expected_4, received_4
+
+    expected_5 = Developer.order('salary DESC').collect(&:name)
+    received_5 = DeveloperOrderedBySalary.where.not("name" => ["Jamis", "David"]).unscope(where: :name).collect(&:name)
+    assert_equal expected_5, received_5
+  end
+
+  def test_unscope_multiple_where_clauses
+    expected = Developer.order('salary DESC').collect { |dev| dev.name }
+    received = DeveloperOrderedBySalary.where(name: 'Jamis').where(id: 1).unscope(where: [:name, :id]).collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_unscope_string_where_clauses_involved
+    dev_relation = Developer.order('salary DESC').where("created_at > ?", 1.year.ago)
+    expected = dev_relation.collect { |dev| dev.name }
+
+    dev_ordered_relation = DeveloperOrderedBySalary.where(name: 'Jamis').where("created_at > ?", 1.year.ago)
+    received = dev_ordered_relation.unscope(where: [:name]).collect { |dev| dev.name }
+
+    assert_equal expected, received
+  end
+
+  def test_unscope_with_grouping_attributes
+    expected = Developer.order('salary DESC').collect { |dev| dev.name }
+    received = DeveloperOrderedBySalary.group(:name).unscope(:group).collect { |dev| dev.name }
+    assert_equal expected, received
+
+    expected_2 = Developer.order('salary DESC').collect { |dev| dev.name }
+    received_2 = DeveloperOrderedBySalary.group("name").unscope(:group).collect { |dev| dev.name }
+    assert_equal expected_2, received_2
+  end
+
+  def test_unscope_with_limit_in_query
+    expected = Developer.order('salary DESC').collect { |dev| dev.name }
+    received = DeveloperOrderedBySalary.limit(1).unscope(:limit).collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_order_to_unscope_reordering
+    scope = DeveloperOrderedBySalary.order('salary DESC, name ASC').reverse_order.unscope(:order)
+    assert !(scope.to_sql =~ /order/i)
+  end
+
+  def test_unscope_reverse_order
+    expected = Developer.all.collect { |dev| dev.name }
+    received = Developer.order('salary DESC').reverse_order.unscope(:order).collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_unscope_select
+    expected = Developer.order('salary ASC').collect { |dev| dev.name }
+    received = Developer.order('salary DESC').reverse_order.select(:name).unscope(:select).collect { |dev| dev.name }
+    assert_equal expected, received
+
+    expected_2 = Developer.all.collect { |dev| dev.id }
+    received_2 = Developer.select(:name).unscope(:select).collect { |dev| dev.id }
+    assert_equal expected_2, received_2
+  end
+
+  def test_unscope_offset
+    expected = Developer.all.collect { |dev| dev.name }
+    received = Developer.offset(5).unscope(:offset).collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_unscope_joins_and_select_on_developers_projects
+    expected = Developer.all.collect { |dev| dev.name }
+    received = Developer.joins('JOIN developers_projects ON id = developer_id').select(:id).unscope(:joins, :select).collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_unscope_includes
+    expected = Developer.all.collect { |dev| dev.name }
+    received = Developer.includes(:projects).select(:id).unscope(:includes, :select).collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_unscope_having
+    expected = DeveloperOrderedBySalary.all.collect { |dev| dev.name }
+    received = DeveloperOrderedBySalary.having("name IN ('Jamis', 'David')").unscope(:having).collect { |dev| dev.name }
+    assert_equal expected, received
+  end
+
+  def test_unscope_and_scope
+    developer_klass = Class.new(Developer) do
+      scope :by_name, -> name { unscope(where: :name).where(name: name) }
+    end
+
+    expected = developer_klass.where(name: 'Jamis').collect { |dev| [dev.name, dev.id] }
+    received = developer_klass.where(name: 'David').by_name('Jamis').collect { |dev| [dev.name, dev.id] }
+    assert_equal expected, received
+  end
+
+  def test_unscope_errors_with_invalid_value
+    assert_raises(ArgumentError) do
+      Developer.includes(:projects).where(name: "Jamis").unscope(:stupidly_incorrect_value)
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.all.unscope(:includes, :select, :some_broken_value)
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.order('name DESC').reverse_order.unscope(:reverse_order)
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.order('name DESC').where(name: "Jamis").unscope()
+    end
+  end
+
+  def test_unscope_errors_with_non_where_hash_keys
+    assert_raises(ArgumentError) do
+      Developer.where(name: "Jamis").limit(4).unscope(limit: 4)
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.where(name: "Jamis").unscope("where" => :name)
+    end
+  end
+
+  def test_unscope_errors_with_non_symbol_or_hash_arguments
+    assert_raises(ArgumentError) do
+      Developer.where(name: "Jamis").limit(3).unscope("limit")
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.select("id").unscope("select")
+    end
+
+    assert_raises(ArgumentError) do
+      Developer.select("id").unscope(5)
+    end
+  end
+
+  def test_unscope_merging
+    merged = Developer.where(name: "Jamis").merge(Developer.unscope(:where))
+    assert merged.where_values.empty?
+    assert !merged.where(name: "Jon").where_values.empty?
+  end
+
+  def test_order_in_default_scope_should_not_prevail
+    expected = Developer.all.merge!(order: 'salary desc').to_a.collect { |dev| dev.salary }
+    received = DeveloperOrderedBySalary.all.merge!(order: 'salary').to_a.collect { |dev| dev.salary }
+    assert_equal expected, received
+  end
+
+  def test_create_attribute_overwrites_default_scoping
+    assert_equal 'David', PoorDeveloperCalledJamis.create!(:name => 'David').name
+    assert_equal 200000, PoorDeveloperCalledJamis.create!(:name => 'David', :salary => 200000).salary
+  end
+
+  def test_create_attribute_overwrites_default_values
+    assert_equal nil, PoorDeveloperCalledJamis.create!(:salary => nil).salary
+    assert_equal 50000, PoorDeveloperCalledJamis.create!(:name => 'David').salary
+  end
+
+  def test_default_scope_attribute
+    jamis = PoorDeveloperCalledJamis.new(:name => 'David')
+    assert_equal 50000, jamis.salary
+  end
+
+  def test_where_attribute
+    aaron = PoorDeveloperCalledJamis.where(:salary => 20).new(:name => 'Aaron')
+    assert_equal 20, aaron.salary
+    assert_equal 'Aaron', aaron.name
+  end
+
+  def test_where_attribute_merge
+    aaron = PoorDeveloperCalledJamis.where(:name => 'foo').new(:name => 'Aaron')
+    assert_equal 'Aaron', aaron.name
+  end
+
+  def test_scope_composed_by_limit_and_then_offset_is_equal_to_scope_composed_by_offset_and_then_limit
+    posts_limit_offset = Post.limit(3).offset(2)
+    posts_offset_limit = Post.offset(2).limit(3)
+    assert_equal posts_limit_offset, posts_offset_limit
+  end
+
+  def test_create_with_merge
+    aaron = PoorDeveloperCalledJamis.create_with(:name => 'foo', :salary => 20).merge(
+              PoorDeveloperCalledJamis.create_with(:name => 'Aaron')).new
+    assert_equal 20, aaron.salary
+    assert_equal 'Aaron', aaron.name
+
+    aaron = PoorDeveloperCalledJamis.create_with(:name => 'foo', :salary => 20).
+                                     create_with(:name => 'Aaron').new
+    assert_equal 20, aaron.salary
+    assert_equal 'Aaron', aaron.name
+  end
+
+  def test_create_with_reset
+    jamis = PoorDeveloperCalledJamis.create_with(:name => 'Aaron').create_with(nil).new
+    assert_equal 'Jamis', jamis.name
+  end
+
+  # FIXME: I don't know if this is *desired* behavior, but it is *today's*
+  # behavior.
+  def test_create_with_empty_hash_will_not_reset
+    jamis = PoorDeveloperCalledJamis.create_with(:name => 'Aaron').create_with({}).new
+    assert_equal 'Aaron', jamis.name
+  end
+
+  def test_unscoped_with_named_scope_should_not_have_default_scope
+    assert_equal [DeveloperCalledJamis.find(developers(:poor_jamis).id)], DeveloperCalledJamis.poor
+
+    assert DeveloperCalledJamis.unscoped.poor.include?(developers(:david).becomes(DeveloperCalledJamis))
+
+    assert_equal 11, DeveloperCalledJamis.unscoped.length
+    assert_equal 1,  DeveloperCalledJamis.poor.length
+    assert_equal 10, DeveloperCalledJamis.unscoped.poor.length
+    assert_equal 10, DeveloperCalledJamis.unscoped { DeveloperCalledJamis.poor }.length
+  end
+
+  def test_default_scope_select_ignored_by_aggregations
+    assert_equal DeveloperWithSelect.all.to_a.count, DeveloperWithSelect.count
+  end
+
+  def test_default_scope_select_ignored_by_grouped_aggregations
+    assert_equal Hash[Developer.all.group_by(&:salary).map { |s, d| [s, d.count] }],
+                 DeveloperWithSelect.group(:salary).count
+  end
+
+  def test_default_scope_order_ignored_by_aggregations
+    assert_equal DeveloperOrderedBySalary.all.count, DeveloperOrderedBySalary.count
+  end
+
+  def test_default_scope_find_last
+    assert DeveloperOrderedBySalary.count > 1, "need more than one row for test"
+
+    lowest_salary_dev = DeveloperOrderedBySalary.find(developers(:poor_jamis).id)
+    assert_equal lowest_salary_dev, DeveloperOrderedBySalary.last
+  end
+
+  def test_default_scope_include_with_count
+    d = DeveloperWithIncludes.create!
+    d.audit_logs.create! :message => 'foo'
+
+    assert_equal 1, DeveloperWithIncludes.where(:audit_logs => { :message => 'foo' }).count
+  end
+
+  unless in_memory_db?
+    def test_default_scope_is_threadsafe
+      threads = []
+      assert_not_equal 1, ThreadsafeDeveloper.unscoped.count
+
+      threads << Thread.new do
+        Thread.current[:long_default_scope] = true
+        assert_equal 1, ThreadsafeDeveloper.all.to_a.count
+        ThreadsafeDeveloper.connection.close
+      end
+      threads << Thread.new do
+        assert_equal 1, ThreadsafeDeveloper.all.to_a.count
+        ThreadsafeDeveloper.connection.close
+      end
+      threads.each(&:join)
+    end
+  end
+
+  test "additional conditions are ANDed with the default scope" do
+    scope = DeveloperCalledJamis.where(name: "David")
+    assert_equal 2, scope.where_values.length
+    assert_equal [], scope.to_a
+  end
+
+  test "additional conditions in a scope are ANDed with the default scope" do
+    scope = DeveloperCalledJamis.david
+    assert_equal 2, scope.where_values.length
+    assert_equal [], scope.to_a
+  end
+
+  test "a scope can remove the condition from the default scope" do
+    scope = DeveloperCalledJamis.david2
+    assert_equal 1, scope.where_values.length
+    assert_equal Developer.where(name: "David").map(&:id), scope.map(&:id)
+  end
+end
diff --git a/activerecord/test/cases/scoping/named_scoping_test.rb b/activerecord/test/cases/scoping/named_scoping_test.rb
new file mode 100644
index 0000000000..59ec2dd6a4
--- /dev/null
+++ b/activerecord/test/cases/scoping/named_scoping_test.rb
@@ -0,0 +1,513 @@
+require "cases/helper"
+require 'models/post'
+require 'models/topic'
+require 'models/comment'
+require 'models/reply'
+require 'models/author'
+require 'models/developer'
+
+class NamedScopingTest < ActiveRecord::TestCase
+  fixtures :posts, :authors, :topics, :comments, :author_addresses
+
+  def test_implements_enumerable
+    assert !Topic.all.empty?
+
+    assert_equal Topic.all.to_a, Topic.base
+    assert_equal Topic.all.to_a, Topic.base.to_a
+    assert_equal Topic.first,    Topic.base.first
+    assert_equal Topic.all.to_a, Topic.base.map { |i| i }
+  end
+
+  def test_found_items_are_cached
+    all_posts = Topic.base
+
+    assert_queries(1) do
+      all_posts.collect
+      all_posts.collect
+    end
+  end
+
+  def test_reload_expires_cache_of_found_items
+    all_posts = Topic.base
+    all_posts.to_a
+
+    new_post = Topic.create!
+    assert !all_posts.include?(new_post)
+    assert all_posts.reload.include?(new_post)
+  end
+
+  def test_delegates_finds_and_calculations_to_the_base_class
+    assert !Topic.all.empty?
+
+    assert_equal Topic.all.to_a,                Topic.base.to_a
+    assert_equal Topic.first,                   Topic.base.first
+    assert_equal Topic.count,                   Topic.base.count
+    assert_equal Topic.average(:replies_count), Topic.base.average(:replies_count)
+  end
+
+  def test_method_missing_priority_when_delegating
+    klazz = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+      scope :since, Proc.new { where('written_on >= ?', Time.now - 1.day) }
+      scope :to,    Proc.new { where('written_on <= ?', Time.now) }
+    end
+    assert_equal klazz.to.since.to_a, klazz.since.to.to_a
+  end
+
+  def test_scope_should_respond_to_own_methods_and_methods_of_the_proxy
+    assert Topic.approved.respond_to?(:limit)
+    assert Topic.approved.respond_to?(:count)
+    assert Topic.approved.respond_to?(:length)
+  end
+
+  def test_scopes_with_options_limit_finds_to_those_matching_the_criteria_specified
+    assert !Topic.all.merge!(:where => {:approved => true}).to_a.empty?
+
+    assert_equal Topic.all.merge!(:where => {:approved => true}).to_a, Topic.approved
+    assert_equal Topic.where(:approved => true).count, Topic.approved.count
+  end
+
+  def test_scopes_with_string_name_can_be_composed
+    # NOTE that scopes defined with a string as a name worked on their own
+    # but when called on another scope the other scope was completely replaced
+    assert_equal Topic.replied.approved, Topic.replied.approved_as_string
+  end
+
+  def test_scopes_are_composable
+    assert_equal((approved = Topic.all.merge!(:where => {:approved => true}).to_a), Topic.approved)
+    assert_equal((replied = Topic.all.merge!(:where => 'replies_count > 0').to_a), Topic.replied)
+    assert !(approved == replied)
+    assert !(approved & replied).empty?
+
+    assert_equal approved & replied, Topic.approved.replied
+  end
+
+  def test_procedural_scopes
+    topics_written_before_the_third = Topic.where('written_on < ?', topics(:third).written_on)
+    topics_written_before_the_second = Topic.where('written_on < ?', topics(:second).written_on)
+    assert_not_equal topics_written_before_the_second, topics_written_before_the_third
+
+    assert_equal topics_written_before_the_third, Topic.written_before(topics(:third).written_on)
+    assert_equal topics_written_before_the_second, Topic.written_before(topics(:second).written_on)
+  end
+
+  def test_procedural_scopes_returning_nil
+    all_topics = Topic.all
+
+    assert_equal all_topics, Topic.written_before(nil)
+  end
+
+  def test_scope_with_object
+    objects = Topic.with_object
+    assert_operator objects.length, :>, 0
+    assert objects.all?(&:approved?), 'all objects should be approved'
+  end
+
+  def test_has_many_associations_have_access_to_scopes
+    assert_not_equal Post.containing_the_letter_a, authors(:david).posts
+    assert !Post.containing_the_letter_a.empty?
+
+    assert_equal authors(:david).posts & Post.containing_the_letter_a, authors(:david).posts.containing_the_letter_a
+  end
+
+  def test_scope_with_STI
+    assert_equal 3,Post.containing_the_letter_a.count
+    assert_equal 1,SpecialPost.containing_the_letter_a.count
+  end
+
+  def test_has_many_through_associations_have_access_to_scopes
+    assert_not_equal Comment.containing_the_letter_e, authors(:david).comments
+    assert !Comment.containing_the_letter_e.empty?
+
+    assert_equal authors(:david).comments & Comment.containing_the_letter_e, authors(:david).comments.containing_the_letter_e
+  end
+
+  def test_scopes_honor_current_scopes_from_when_defined
+    assert !Post.ranked_by_comments.limit_by(5).empty?
+    assert !authors(:david).posts.ranked_by_comments.limit_by(5).empty?
+    assert_not_equal Post.ranked_by_comments.limit_by(5), authors(:david).posts.ranked_by_comments.limit_by(5)
+    assert_not_equal Post.top(5), authors(:david).posts.top(5)
+    # Oracle sometimes sorts differently if WHERE condition is changed
+    assert_equal authors(:david).posts.ranked_by_comments.limit_by(5).to_a.sort_by(&:id), authors(:david).posts.top(5).to_a.sort_by(&:id)
+    assert_equal Post.ranked_by_comments.limit_by(5), Post.top(5)
+  end
+
+  def test_active_records_have_scope_named__all__
+    assert !Topic.all.empty?
+
+    assert_equal Topic.all.to_a, Topic.base
+  end
+
+  def test_active_records_have_scope_named__scoped__
+    scope = Topic.where("content LIKE '%Have%'")
+    assert !scope.empty?
+
+    assert_equal scope, Topic.all.merge!(where: "content LIKE '%Have%'")
+  end
+
+  def test_first_and_last_should_allow_integers_for_limit
+    assert_equal Topic.base.first(2), Topic.base.to_a.first(2)
+    assert_equal Topic.base.last(2), Topic.base.order("id").to_a.last(2)
+  end
+
+  def test_first_and_last_should_not_use_query_when_results_are_loaded
+    topics = Topic.base
+    topics.reload # force load
+    assert_no_queries do
+      topics.first
+      topics.last
+    end
+  end
+
+  def test_empty_should_not_load_results
+    topics = Topic.base
+    assert_queries(2) do
+      topics.empty?  # use count query
+      topics.collect # force load
+      topics.empty?  # use loaded (no query)
+    end
+  end
+
+  def test_any_should_not_load_results
+    topics = Topic.base
+    assert_queries(2) do
+      topics.any?    # use count query
+      topics.collect # force load
+      topics.any?    # use loaded (no query)
+    end
+  end
+
+  def test_any_should_call_proxy_found_if_using_a_block
+    topics = Topic.base
+    assert_queries(1) do
+      topics.expects(:empty?).never
+      topics.any? { true }
+    end
+  end
+
+  def test_any_should_not_fire_query_if_scope_loaded
+    topics = Topic.base
+    topics.collect # force load
+    assert_no_queries { assert topics.any? }
+  end
+
+  def test_model_class_should_respond_to_any
+    assert Topic.any?
+    Topic.delete_all
+    assert !Topic.any?
+  end
+
+  def test_many_should_not_load_results
+    topics = Topic.base
+    assert_queries(2) do
+      topics.many?   # use count query
+      topics.collect # force load
+      topics.many?   # use loaded (no query)
+    end
+  end
+
+  def test_many_should_call_proxy_found_if_using_a_block
+    topics = Topic.base
+    assert_queries(1) do
+      topics.expects(:size).never
+      topics.many? { true }
+    end
+  end
+
+  def test_many_should_not_fire_query_if_scope_loaded
+    topics = Topic.base
+    topics.collect # force load
+    assert_no_queries { assert topics.many? }
+  end
+
+  def test_many_should_return_false_if_none_or_one
+    topics = Topic.base.where(:id => 0)
+    assert !topics.many?
+    topics = Topic.base.where(:id => 1)
+    assert !topics.many?
+  end
+
+  def test_many_should_return_true_if_more_than_one
+    assert Topic.base.many?
+  end
+
+  def test_model_class_should_respond_to_many
+    Topic.delete_all
+    assert !Topic.many?
+    Topic.create!
+    assert !Topic.many?
+    Topic.create!
+    assert Topic.many?
+  end
+
+  def test_should_build_on_top_of_scope
+    topic = Topic.approved.build({})
+    assert topic.approved
+  end
+
+  def test_should_build_new_on_top_of_scope
+    topic = Topic.approved.new
+    assert topic.approved
+  end
+
+  def test_should_create_on_top_of_scope
+    topic = Topic.approved.create({})
+    assert topic.approved
+  end
+
+  def test_should_create_with_bang_on_top_of_scope
+    topic = Topic.approved.create!({})
+    assert topic.approved
+  end
+
+  def test_should_build_on_top_of_chained_scopes
+    topic = Topic.approved.by_lifo.build({})
+    assert topic.approved
+    assert_equal 'lifo', topic.author_name
+  end
+
+  def test_reserved_scope_names
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+
+      scope :approved, -> { where(approved: true) }
+
+      class << self
+        public
+          def pub; end
+
+        private
+          def pri; end
+
+        protected
+          def pro; end
+      end
+    end
+
+    subklass = Class.new(klass)
+
+    conflicts = [
+      :create,        # public class method on AR::Base
+      :relation,      # private class method on AR::Base
+      :new,           # redefined class method on AR::Base
+      :all,           # a default scope
+      :public,
+      :protected,
+      :private
+    ]
+
+    non_conflicts = [
+      :find_by_title, # dynamic finder method
+      :approved,      # existing scope
+      :pub,           # existing public class method
+      :pri,           # existing private class method
+      :pro,           # existing protected class method
+      :open,          # a ::Kernel method
+    ]
+
+    conflicts.each do |name|
+      assert_raises(ArgumentError, "scope `#{name}` should not be allowed") do
+        klass.class_eval { scope name, ->{ where(approved: true) } }
+      end
+
+      assert_raises(ArgumentError, "scope `#{name}` should not be allowed") do
+        subklass.class_eval { scope name, ->{ where(approved: true) } }
+      end
+    end
+
+    non_conflicts.each do |name|
+      assert_nothing_raised do
+        silence_warnings do
+          klass.class_eval { scope name, ->{ where(approved: true) } }
+        end
+      end
+
+      assert_nothing_raised do
+        subklass.class_eval { scope name, ->{ where(approved: true) } }
+      end
+    end
+  end
+
+  # Method delegation for scope names which look like /\A[a-zA-Z_]\w*[!?]?\z/
+  # has been done by evaluating a string with a plain def statement. For scope
+  # names which contain spaces this approach doesn't work.
+  def test_spaces_in_scope_names
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+      scope :"title containing space", -> { where("title LIKE '% %'") }
+      scope :approved, -> { where(:approved => true) }
+    end
+    assert_equal klass.send(:"title containing space"), klass.where("title LIKE '% %'")
+    assert_equal klass.approved.send(:"title containing space"), klass.approved.where("title LIKE '% %'")
+  end
+
+  def test_find_all_should_behave_like_select
+    assert_equal Topic.base.to_a.select(&:approved), Topic.base.to_a.find_all(&:approved)
+  end
+
+  def test_rand_should_select_a_random_object_from_proxy
+    assert_kind_of Topic, Topic.approved.sample
+  end
+
+  def test_should_use_where_in_query_for_scope
+    assert_equal Developer.where(name: 'Jamis').to_set, Developer.where(id: Developer.jamises).to_set
+  end
+
+  def test_size_should_use_count_when_results_are_not_loaded
+    topics = Topic.base
+    assert_queries(1) do
+      assert_sql(/COUNT/i) { topics.size }
+    end
+  end
+
+  def test_size_should_use_length_when_results_are_loaded
+    topics = Topic.base
+    topics.reload # force load
+    assert_no_queries do
+      topics.size # use loaded (no query)
+    end
+  end
+
+  def test_should_not_duplicates_where_values
+    where_values = Topic.where("1=1").scope_with_lambda.where_values
+    assert_equal ["1=1"], where_values
+  end
+
+  def test_chaining_with_duplicate_joins
+    join = "INNER JOIN comments ON comments.post_id = posts.id"
+    post = Post.find(1)
+    assert_equal post.comments.size, Post.joins(join).joins(join).where("posts.id = #{post.id}").size
+  end
+
+  def test_chaining_applies_last_conditions_when_creating
+    post = Topic.rejected.new
+    assert !post.approved?
+
+    post = Topic.rejected.approved.new
+    assert post.approved?
+
+    post = Topic.approved.rejected.new
+    assert !post.approved?
+
+    post = Topic.approved.rejected.approved.new
+    assert post.approved?
+  end
+
+  def test_chaining_combines_conditions_when_searching
+    # Normal hash conditions
+    assert_equal Topic.where(approved: false).where(approved: true).to_a, Topic.rejected.approved.to_a
+    assert_equal Topic.where(approved: true).where(approved: false).to_a, Topic.approved.rejected.to_a
+
+    # Nested hash conditions with same keys
+    assert_equal [], Post.with_special_comments.with_very_special_comments.to_a
+
+    # Nested hash conditions with different keys
+    assert_equal [posts(:sti_comments)], Post.with_special_comments.with_post(4).to_a.uniq
+  end
+
+  def test_scopes_batch_finders
+    assert_equal 4, Topic.approved.count
+
+    assert_queries(5) do
+      Topic.approved.find_each(:batch_size => 1) {|t| assert t.approved? }
+    end
+
+    assert_queries(3) do
+      Topic.approved.find_in_batches(:batch_size => 2) do |group|
+        group.each {|t| assert t.approved? }
+      end
+    end
+  end
+
+  def test_table_names_for_chaining_scopes_with_and_without_table_name_included
+    assert_nothing_raised do
+      Comment.for_first_post.for_first_author.to_a
+    end
+  end
+
+  def test_scopes_on_relations
+    # Topic.replied
+    approved_topics = Topic.all.approved.order('id DESC')
+    assert_equal topics(:fifth), approved_topics.first
+
+    replied_approved_topics = approved_topics.replied
+    assert_equal topics(:third), replied_approved_topics.first
+  end
+
+  def test_index_on_scope
+    approved = Topic.approved.order('id ASC')
+    assert_equal topics(:second), approved[0]
+    assert approved.loaded?
+  end
+
+  def test_nested_scopes_queries_size
+    assert_queries(1) do
+      Topic.approved.by_lifo.replied.written_before(Time.now).to_a
+    end
+  end
+
+  # Note: these next two are kinda odd because they are essentially just testing that the
+  # query cache works as it should, but they are here for legacy reasons as they was previously
+  # a separate cache on association proxies, and these show that that is not necessary.
+  def test_scopes_are_cached_on_associations
+    post = posts(:welcome)
+
+    Post.cache do
+      assert_queries(1) { post.comments.containing_the_letter_e.to_a }
+      assert_no_queries { post.comments.containing_the_letter_e.to_a }
+    end
+  end
+
+  def test_scopes_with_arguments_are_cached_on_associations
+    post = posts(:welcome)
+
+    Post.cache do
+      one = assert_queries(1) { post.comments.limit_by(1).to_a }
+      assert_equal 1, one.size
+
+      two = assert_queries(1) { post.comments.limit_by(2).to_a }
+      assert_equal 2, two.size
+
+      assert_no_queries { post.comments.limit_by(1).to_a }
+      assert_no_queries { post.comments.limit_by(2).to_a }
+    end
+  end
+
+  def test_scopes_to_get_newest
+    post = posts(:welcome)
+    old_last_comment = post.comments.newest
+    new_comment = post.comments.create(:body => "My new comment")
+    assert_equal new_comment, post.comments.newest
+    assert_not_equal old_last_comment, post.comments.newest
+  end
+
+  def test_scopes_are_reset_on_association_reload
+    post = posts(:welcome)
+
+    [:destroy_all, :reset, :delete_all].each do |method|
+      before = post.comments.containing_the_letter_e
+      post.association(:comments).send(method)
+      assert before.object_id != post.comments.containing_the_letter_e.object_id, "CollectionAssociation##{method} should reset the named scopes cache"
+    end
+  end
+
+  def test_scoped_are_lazy_loaded_if_table_still_does_not_exist
+    assert_nothing_raised do
+      require "models/without_table"
+    end
+  end
+
+  def test_eager_default_scope_relations_are_remove
+    klass = Class.new(ActiveRecord::Base)
+    klass.table_name = 'posts'
+
+    assert_raises(ArgumentError) do
+      klass.send(:default_scope, klass.where(:id => posts(:welcome).id))
+    end
+  end
+
+  def test_subclass_merges_scopes_properly
+    assert_equal 1, SpecialComment.where(body: 'go crazy').created.count
+  end
+
+end
diff --git a/activerecord/test/cases/scoping/relation_scoping_test.rb b/activerecord/test/cases/scoping/relation_scoping_test.rb
new file mode 100644
index 0000000000..d8a467ec4d
--- /dev/null
+++ b/activerecord/test/cases/scoping/relation_scoping_test.rb
@@ -0,0 +1,332 @@
+require "cases/helper"
+require 'models/post'
+require 'models/author'
+require 'models/developer'
+require 'models/project'
+require 'models/comment'
+require 'models/category'
+require 'models/person'
+require 'models/reference'
+
+class RelationScopingTest < ActiveRecord::TestCase
+  fixtures :authors, :developers, :projects, :comments, :posts, :developers_projects
+
+  def test_reverse_order
+    assert_equal Developer.order("id DESC").to_a.reverse, Developer.order("id DESC").reverse_order
+  end
+
+  def test_reverse_order_with_arel_node
+    assert_equal Developer.order("id DESC").to_a.reverse, Developer.order(Developer.arel_table[:id].desc).reverse_order
+  end
+
+  def test_reverse_order_with_multiple_arel_nodes
+    assert_equal Developer.order("id DESC").order("name DESC").to_a.reverse, Developer.order(Developer.arel_table[:id].desc).order(Developer.arel_table[:name].desc).reverse_order
+  end
+
+  def test_reverse_order_with_arel_nodes_and_strings
+    assert_equal Developer.order("id DESC").order("name DESC").to_a.reverse, Developer.order("id DESC").order(Developer.arel_table[:name].desc).reverse_order
+  end
+
+  def test_double_reverse_order_produces_original_order
+    assert_equal Developer.order("name DESC"), Developer.order("name DESC").reverse_order.reverse_order
+  end
+
+  def test_scoped_find
+    Developer.where("name = 'David'").scoping do
+      assert_nothing_raised { Developer.find(1) }
+    end
+  end
+
+  def test_scoped_find_first
+    developer = Developer.find(10)
+    Developer.where("salary = 100000").scoping do
+      assert_equal developer, Developer.order("name").first
+    end
+  end
+
+  def test_scoped_find_last
+    highest_salary = Developer.order("salary DESC").first
+
+    Developer.order("salary").scoping do
+      assert_equal highest_salary, Developer.last
+    end
+  end
+
+  def test_scoped_find_last_preserves_scope
+    lowest_salary  = Developer.order("salary ASC").first
+    highest_salary = Developer.order("salary DESC").first
+
+    Developer.order("salary").scoping do
+      assert_equal highest_salary, Developer.last
+      assert_equal lowest_salary, Developer.first
+    end
+  end
+
+  def test_scoped_find_combines_and_sanitizes_conditions
+    Developer.where("salary = 9000").scoping do
+      assert_equal developers(:poor_jamis), Developer.where("name = 'Jamis'").first
+    end
+  end
+
+  def test_scoped_find_all
+    Developer.where("name = 'David'").scoping do
+      assert_equal [developers(:david)], Developer.all
+    end
+  end
+
+  def test_scoped_find_select
+    Developer.select("id, name").scoping do
+      developer = Developer.where("name = 'David'").first
+      assert_equal "David", developer.name
+      assert !developer.has_attribute?(:salary)
+    end
+  end
+
+  def test_scope_select_concatenates
+    Developer.select("id, name").scoping do
+      developer = Developer.select('salary').where("name = 'David'").first
+      assert_equal 80000, developer.salary
+      assert developer.has_attribute?(:id)
+      assert developer.has_attribute?(:name)
+      assert developer.has_attribute?(:salary)
+    end
+  end
+
+  def test_scoped_count
+    Developer.where("name = 'David'").scoping do
+      assert_equal 1, Developer.count
+    end
+
+    Developer.where('salary = 100000').scoping do
+      assert_equal 8, Developer.count
+      assert_equal 1, Developer.where("name LIKE 'fixture_1%'").count
+    end
+  end
+
+  def test_scoped_find_include
+    # with the include, will retrieve only developers for the given project
+    scoped_developers = Developer.includes(:projects).scoping do
+      Developer.where('projects.id' => 2).to_a
+    end
+    assert scoped_developers.include?(developers(:david))
+    assert !scoped_developers.include?(developers(:jamis))
+    assert_equal 1, scoped_developers.size
+  end
+
+  def test_scoped_find_joins
+    scoped_developers = Developer.joins('JOIN developers_projects ON id = developer_id').scoping do
+      Developer.where('developers_projects.project_id = 2').to_a
+    end
+
+    assert scoped_developers.include?(developers(:david))
+    assert !scoped_developers.include?(developers(:jamis))
+    assert_equal 1, scoped_developers.size
+    assert_equal developers(:david).attributes, scoped_developers.first.attributes
+  end
+
+  def test_scoped_create_with_where
+    new_comment = VerySpecialComment.where(:post_id => 1).scoping do
+      VerySpecialComment.create :body => "Wonderful world"
+    end
+
+    assert_equal 1, new_comment.post_id
+    assert Post.find(1).comments.include?(new_comment)
+  end
+
+  def test_scoped_create_with_create_with
+    new_comment = VerySpecialComment.create_with(:post_id => 1).scoping do
+      VerySpecialComment.create :body => "Wonderful world"
+    end
+
+    assert_equal 1, new_comment.post_id
+    assert Post.find(1).comments.include?(new_comment)
+  end
+
+  def test_scoped_create_with_create_with_has_higher_priority
+    new_comment = VerySpecialComment.where(:post_id => 2).create_with(:post_id => 1).scoping do
+      VerySpecialComment.create :body => "Wonderful world"
+    end
+
+    assert_equal 1, new_comment.post_id
+    assert Post.find(1).comments.include?(new_comment)
+  end
+
+  def test_ensure_that_method_scoping_is_correctly_restored
+    begin
+      Developer.where("name = 'Jamis'").scoping do
+        raise "an exception"
+      end
+    rescue
+    end
+
+    assert !Developer.all.where_values.include?("name = 'Jamis'")
+  end
+
+  def test_default_scope_filters_on_joins
+    assert_equal 1, DeveloperFilteredOnJoins.all.count
+    assert_equal DeveloperFilteredOnJoins.all.first, developers(:david).becomes(DeveloperFilteredOnJoins)
+  end
+
+  def test_update_all_default_scope_filters_on_joins
+    DeveloperFilteredOnJoins.update_all(:salary => 65000)
+    assert_equal 65000, Developer.find(developers(:david).id).salary
+
+    # has not changed jamis
+    assert_not_equal 65000, Developer.find(developers(:jamis).id).salary
+  end
+
+  def test_delete_all_default_scope_filters_on_joins
+    assert_not_equal [], DeveloperFilteredOnJoins.all
+
+    DeveloperFilteredOnJoins.delete_all()
+
+    assert_equal [], DeveloperFilteredOnJoins.all
+    assert_not_equal [], Developer.all
+  end
+end
+
+class NestedRelationScopingTest < ActiveRecord::TestCase
+  fixtures :authors, :developers, :projects, :comments, :posts
+
+  def test_merge_options
+    Developer.where('salary = 80000').scoping do
+      Developer.limit(10).scoping do
+        devs = Developer.all
+        sql = devs.to_sql
+        assert_match '(salary = 80000)', sql
+        assert_match 'LIMIT 10', sql
+      end
+    end
+  end
+
+  def test_merge_inner_scope_has_priority
+    Developer.limit(5).scoping do
+      Developer.limit(10).scoping do
+        assert_equal 10, Developer.all.size
+      end
+    end
+  end
+
+  def test_replace_options
+    Developer.where(:name => 'David').scoping do
+      Developer.unscoped do
+        assert_equal 'Jamis', Developer.where(:name => 'Jamis').first[:name]
+      end
+
+      assert_equal 'David', Developer.first[:name]
+    end
+  end
+
+  def test_three_level_nested_exclusive_scoped_find
+    Developer.where("name = 'Jamis'").scoping do
+      assert_equal 'Jamis', Developer.first.name
+
+      Developer.unscoped.where("name = 'David'") do
+        assert_equal 'David', Developer.first.name
+
+        Developer.unscoped.where("name = 'Maiha'") do
+          assert_equal nil, Developer.first
+        end
+
+        # ensure that scoping is restored
+        assert_equal 'David', Developer.first.name
+      end
+
+      # ensure that scoping is restored
+      assert_equal 'Jamis', Developer.first.name
+    end
+  end
+
+  def test_nested_scoped_create
+    comment = Comment.create_with(:post_id => 1).scoping do
+      Comment.create_with(:post_id => 2).scoping do
+        Comment.create :body => "Hey guys, nested scopes are broken. Please fix!"
+      end
+    end
+
+    assert_equal 2, comment.post_id
+  end
+
+  def test_nested_exclusive_scope_for_create
+    comment = Comment.create_with(:body => "Hey guys, nested scopes are broken. Please fix!").scoping do
+      Comment.unscoped.create_with(:post_id => 1).scoping do
+        assert Comment.new.body.blank?
+        Comment.create :body => "Hey guys"
+      end
+    end
+
+    assert_equal 1, comment.post_id
+    assert_equal 'Hey guys', comment.body
+  end
+end
+
+class HasManyScopingTest< ActiveRecord::TestCase
+  fixtures :comments, :posts, :people, :references
+
+  def setup
+    @welcome = Post.find(1)
+  end
+
+  def test_forwarding_of_static_methods
+    assert_equal 'a comment...', Comment.what_are_you
+    assert_equal 'a comment...', @welcome.comments.what_are_you
+  end
+
+  def test_forwarding_to_scoped
+    assert_equal 4, Comment.search_by_type('Comment').size
+    assert_equal 2, @welcome.comments.search_by_type('Comment').size
+  end
+
+  def test_nested_scope_finder
+    Comment.where('1=0').scoping do
+      assert_equal 0, @welcome.comments.count
+      assert_equal 'a comment...', @welcome.comments.what_are_you
+    end
+
+    Comment.where('1=1').scoping do
+      assert_equal 2, @welcome.comments.count
+      assert_equal 'a comment...', @welcome.comments.what_are_you
+    end
+  end
+
+  def test_should_maintain_default_scope_on_associations
+    magician = BadReference.find(1)
+    assert_equal [magician], people(:michael).bad_references
+  end
+
+  def test_should_default_scope_on_associations_is_overridden_by_association_conditions
+    reference = references(:michael_unicyclist).becomes(BadReference)
+    assert_equal [reference], people(:michael).fixed_bad_references
+  end
+
+  def test_should_maintain_default_scope_on_eager_loaded_associations
+    michael = Person.where(:id => people(:michael).id).includes(:bad_references).first
+    magician = BadReference.find(1)
+    assert_equal [magician], michael.bad_references
+  end
+end
+
+class HasAndBelongsToManyScopingTest< ActiveRecord::TestCase
+  fixtures :posts, :categories, :categories_posts
+
+  def setup
+    @welcome = Post.find(1)
+  end
+
+  def test_forwarding_of_static_methods
+    assert_equal 'a category...', Category.what_are_you
+    assert_equal 'a category...', @welcome.categories.what_are_you
+  end
+
+  def test_nested_scope_finder
+    Category.where('1=0').scoping do
+      assert_equal 0, @welcome.categories.count
+      assert_equal 'a category...', @welcome.categories.what_are_you
+    end
+
+    Category.where('1=1').scoping do
+      assert_equal 2, @welcome.categories.count
+      assert_equal 'a category...', @welcome.categories.what_are_you
+    end
+  end
+end
diff --git a/activerecord/test/cases/serialization_test.rb b/activerecord/test/cases/serialization_test.rb
new file mode 100644
index 0000000000..3f52e80e11
--- /dev/null
+++ b/activerecord/test/cases/serialization_test.rb
@@ -0,0 +1,95 @@
+require "cases/helper"
+require 'models/contact'
+require 'models/topic'
+require 'models/book'
+
+class SerializationTest < ActiveRecord::TestCase
+  fixtures :books
+
+  FORMATS = [ :xml, :json ]
+
+  def setup
+    @contact_attributes = {
+      :name           => 'aaron stack',
+      :age            => 25,
+      :avatar         => 'binarydata',
+      :created_at     => Time.utc(2006, 8, 1),
+      :awesome        => false,
+      :preferences    => { :gem => '<strong>ruby</strong>' },
+      :alternative_id => nil,
+      :id             => nil
+    }
+  end
+
+  def test_include_root_in_json_is_false_by_default
+    assert_equal false, ActiveRecord::Base.include_root_in_json, "include_root_in_json should be false by default but was not"
+  end
+
+  def test_serialize_should_be_reversible
+    FORMATS.each do |format|
+      @serialized = Contact.new.send("to_#{format}")
+      contact = Contact.new.send("from_#{format}", @serialized)
+
+      assert_equal @contact_attributes.keys.collect(&:to_s).sort, contact.attributes.keys.collect(&:to_s).sort, "For #{format}"
+    end
+  end
+
+  def test_serialize_should_allow_attribute_only_filtering
+    FORMATS.each do |format|
+      @serialized = Contact.new(@contact_attributes).send("to_#{format}", :only => [ :age, :name ])
+      contact = Contact.new.send("from_#{format}", @serialized)
+      assert_equal @contact_attributes[:name], contact.name, "For #{format}"
+      assert_nil contact.avatar, "For #{format}"
+    end
+  end
+
+  def test_serialize_should_allow_attribute_except_filtering
+    FORMATS.each do |format|
+      @serialized = Contact.new(@contact_attributes).send("to_#{format}", :except => [ :age, :name ])
+      contact = Contact.new.send("from_#{format}", @serialized)
+      assert_nil contact.name, "For #{format}"
+      assert_nil contact.age, "For #{format}"
+      assert_equal @contact_attributes[:awesome], contact.awesome, "For #{format}"
+    end
+  end
+
+  def test_include_root_in_json_allows_inheritance
+    original_root_in_json = ActiveRecord::Base.include_root_in_json
+    ActiveRecord::Base.include_root_in_json = true
+
+    klazz = Class.new(ActiveRecord::Base)
+    klazz.table_name = 'topics'
+    assert klazz.include_root_in_json
+
+    klazz.include_root_in_json = false
+    assert ActiveRecord::Base.include_root_in_json
+    assert !klazz.include_root_in_json
+    assert !klazz.new.include_root_in_json
+  ensure
+    ActiveRecord::Base.include_root_in_json = original_root_in_json
+  end
+
+  def test_read_attribute_for_serialization_with_format_without_method_missing
+    klazz = Class.new(ActiveRecord::Base)
+    klazz.table_name = 'books'
+
+    book = klazz.new
+    assert_nil book.read_attribute_for_serialization(:format)
+  end
+
+  def test_read_attribute_for_serialization_with_format_after_init
+    klazz = Class.new(ActiveRecord::Base)
+    klazz.table_name = 'books'
+
+    book = klazz.new(format: 'paperback')
+    assert_equal 'paperback', book.read_attribute_for_serialization(:format)
+  end
+
+  def test_read_attribute_for_serialization_with_format_after_find
+    klazz = Class.new(ActiveRecord::Base)
+    klazz.table_name = 'books'
+
+    book = klazz.find(books(:awdr).id)
+    assert_equal 'paperback', book.read_attribute_for_serialization(:format)
+  end
+end
diff --git a/activerecord/test/cases/serialized_attribute_test.rb b/activerecord/test/cases/serialized_attribute_test.rb
new file mode 100644
index 0000000000..f8d87a3661
--- /dev/null
+++ b/activerecord/test/cases/serialized_attribute_test.rb
@@ -0,0 +1,258 @@
+require 'cases/helper'
+require 'models/topic'
+require 'models/reply'
+require 'models/person'
+require 'models/traffic_light'
+require 'models/post'
+require 'bcrypt'
+
+class SerializedAttributeTest < ActiveRecord::TestCase
+  fixtures :topics, :posts
+
+  MyObject = Struct.new :attribute1, :attribute2
+
+  teardown do
+    Topic.serialize("content")
+  end
+
+  def test_serialize_does_not_eagerly_load_columns
+    assert_no_queries do
+      Topic.reset_column_information
+      Topic.serialize(:content)
+    end
+  end
+
+  def test_list_of_serialized_attributes
+    assert_deprecated do
+      assert_equal %w(content), Topic.serialized_attributes.keys
+    end
+  end
+
+  def test_serialized_attribute
+    Topic.serialize("content", MyObject)
+
+    myobj = MyObject.new('value1', 'value2')
+    topic = Topic.create("content" => myobj)
+    assert_equal(myobj, topic.content)
+
+    topic.reload
+    assert_equal(myobj, topic.content)
+  end
+
+  def test_serialized_attribute_in_base_class
+    Topic.serialize("content", Hash)
+
+    hash = { 'content1' => 'value1', 'content2' => 'value2' }
+    important_topic = ImportantTopic.create("content" => hash)
+    assert_equal(hash, important_topic.content)
+
+    important_topic.reload
+    assert_equal(hash, important_topic.content)
+  end
+
+  def test_serialized_attributes_from_database_on_subclass
+    Topic.serialize :content, Hash
+
+    t = Reply.new(content: { foo: :bar })
+    assert_equal({ foo: :bar }, t.content)
+    t.save!
+    t = Reply.last
+    assert_equal({ foo: :bar }, t.content)
+  end
+
+  def test_serialized_attribute_calling_dup_method
+    Topic.serialize :content, JSON
+
+    orig = Topic.new(content: { foo: :bar })
+    clone = orig.dup
+    assert_equal(orig.content, clone.content)
+  end
+
+  def test_serialized_json_attribute_returns_unserialized_value
+    Topic.serialize :content, JSON
+    my_post = posts(:welcome)
+
+    t = Topic.new(content: my_post)
+    t.save!
+    t.reload
+
+    assert_instance_of(Hash, t.content)
+    assert_equal(my_post.id, t.content["id"])
+    assert_equal(my_post.title, t.content["title"])
+  end
+
+  def test_json_read_legacy_null
+    Topic.serialize :content, JSON
+
+    # Force a row to have a JSON "null" instead of a database NULL (this is how
+    # null values are saved on 4.1 and before)
+    id = Topic.connection.insert "INSERT INTO topics (content) VALUES('null')"
+    t = Topic.find(id)
+
+    assert_nil t.content
+  end
+
+  def test_json_read_db_null
+    Topic.serialize :content, JSON
+
+    # Force a row to have a database NULL instead of a JSON "null"
+    id = Topic.connection.insert "INSERT INTO topics (content) VALUES(NULL)"
+    t = Topic.find(id)
+
+    assert_nil t.content
+  end
+
+  def test_serialized_attribute_declared_in_subclass
+    hash = { 'important1' => 'value1', 'important2' => 'value2' }
+    important_topic = ImportantTopic.create("important" => hash)
+    assert_equal(hash, important_topic.important)
+
+    important_topic.reload
+    assert_equal(hash, important_topic.important)
+    assert_equal(hash, important_topic.read_attribute(:important))
+  end
+
+  def test_serialized_time_attribute
+    myobj = Time.local(2008,1,1,1,0)
+    topic = Topic.create("content" => myobj).reload
+    assert_equal(myobj, topic.content)
+  end
+
+  def test_serialized_string_attribute
+    myobj = "Yes"
+    topic = Topic.create("content" => myobj).reload
+    assert_equal(myobj, topic.content)
+  end
+
+  def test_nil_serialized_attribute_without_class_constraint
+    topic = Topic.new
+    assert_nil topic.content
+  end
+
+  def test_nil_not_serialized_without_class_constraint
+    assert Topic.new(:content => nil).save
+    assert_equal 1, Topic.where(:content => nil).count
+  end
+
+  def test_nil_not_serialized_with_class_constraint
+    Topic.serialize :content, Hash
+    assert Topic.new(:content => nil).save
+    assert_equal 1, Topic.where(:content => nil).count
+  end
+
+  def test_serialized_attribute_should_raise_exception_on_save_with_wrong_type
+    Topic.serialize(:content, Hash)
+    assert_raise(ActiveRecord::SerializationTypeMismatch) do
+      topic = Topic.new(content: 'string')
+      topic.save
+    end
+  end
+
+  def test_should_raise_exception_on_serialized_attribute_with_type_mismatch
+    myobj = MyObject.new('value1', 'value2')
+    topic = Topic.new(:content => myobj)
+    assert topic.save
+    Topic.serialize(:content, Hash)
+    assert_raise(ActiveRecord::SerializationTypeMismatch) { Topic.find(topic.id).content }
+  end
+
+  def test_serialized_attribute_with_class_constraint
+    settings = { "color" => "blue" }
+    Topic.serialize(:content, Hash)
+    topic = Topic.new(:content => settings)
+    assert topic.save
+    assert_equal(settings, Topic.find(topic.id).content)
+  end
+
+  def test_serialized_default_class
+    Topic.serialize(:content, Hash)
+    topic = Topic.new
+    assert_equal Hash, topic.content.class
+    assert_equal Hash, topic.read_attribute(:content).class
+    topic.content["beer"] = "MadridRb"
+    assert topic.save
+    topic.reload
+    assert_equal Hash, topic.content.class
+    assert_equal "MadridRb", topic.content["beer"]
+  end
+
+  def test_serialized_no_default_class_for_object
+    topic = Topic.new
+    assert_nil topic.content
+  end
+
+  def test_serialized_boolean_value_true
+    topic = Topic.new(:content => true)
+    assert topic.save
+    topic = topic.reload
+    assert_equal topic.content, true
+  end
+
+  def test_serialized_boolean_value_false
+    topic = Topic.new(:content => false)
+    assert topic.save
+    topic = topic.reload
+    assert_equal topic.content, false
+  end
+
+  def test_serialize_with_coder
+    some_class = Struct.new(:foo) do
+      def self.dump(value)
+        value.foo
+      end
+
+      def self.load(value)
+        new(value)
+      end
+    end
+
+    Topic.serialize(:content, some_class)
+    topic = Topic.new(:content => some_class.new('my value'))
+    topic.save!
+    topic.reload
+    assert_kind_of some_class, topic.content
+    assert_equal topic.content, some_class.new('my value')
+  end
+
+  def test_serialize_attribute_via_select_method_when_time_zone_available
+    with_timezone_config aware_attributes: true do
+      Topic.serialize(:content, MyObject)
+
+      myobj = MyObject.new('value1', 'value2')
+      topic = Topic.create(content: myobj)
+
+      assert_equal(myobj, Topic.select(:content).find(topic.id).content)
+      assert_raise(ActiveModel::MissingAttributeError) { Topic.select(:id).find(topic.id).content }
+    end
+  end
+
+  def test_serialize_attribute_can_be_serialized_in_an_integer_column
+    insures = ['life']
+    person = SerializedPerson.new(first_name: 'David', insures: insures)
+    assert person.save
+    person = person.reload
+    assert_equal(insures, person.insures)
+  end
+
+  def test_regression_serialized_default_on_text_column_with_null_false
+    light = TrafficLight.new
+    assert_equal [], light.state
+    assert_equal [], light.long_state
+  end
+
+  def test_serialized_column_should_unserialize_after_update_column
+    t = Topic.create(content: "first")
+    assert_equal("first", t.content)
+
+    t.update_column(:content, Topic.type_for_attribute('content').type_cast_for_database("second"))
+    assert_equal("second", t.content)
+  end
+
+  def test_serialized_column_should_unserialize_after_update_attribute
+    t = Topic.create(content: "first")
+    assert_equal("first", t.content)
+
+    t.update_attribute(:content, "second")
+    assert_equal("second", t.content)
+  end
+end
diff --git a/activerecord/test/cases/statement_cache_test.rb b/activerecord/test/cases/statement_cache_test.rb
new file mode 100644
index 0000000000..a704b861cb
--- /dev/null
+++ b/activerecord/test/cases/statement_cache_test.rb
@@ -0,0 +1,98 @@
+require 'cases/helper'
+require 'models/book'
+require 'models/liquid'
+require 'models/molecule'
+require 'models/electron'
+
+module ActiveRecord
+  class StatementCacheTest < ActiveRecord::TestCase
+    def setup
+      @connection = ActiveRecord::Base.connection
+    end
+
+    #Cache v 1.1 tests
+    def test_statement_cache
+      Book.create(name: "my book")
+      Book.create(name: "my other book")
+
+      cache = StatementCache.create(Book.connection) do |params|
+        Book.where(:name => params.bind)
+      end
+
+      b = cache.execute([ "my book" ], Book, Book.connection)
+      assert_equal "my book", b[0].name
+      b = cache.execute([ "my other book" ], Book, Book.connection)
+      assert_equal "my other book", b[0].name
+    end
+
+
+    def test_statement_cache_id
+      b1 = Book.create(name: "my book")
+      b2 = Book.create(name: "my other book")
+
+      cache = StatementCache.create(Book.connection) do |params|
+        Book.where(id: params.bind)
+      end
+
+      b = cache.execute([ b1.id ], Book, Book.connection)
+      assert_equal b1.name, b[0].name
+      b = cache.execute([ b2.id ], Book, Book.connection)
+      assert_equal b2.name, b[0].name
+    end
+
+    def test_find_or_create_by
+      Book.create(name: "my book")
+
+      a = Book.find_or_create_by(name: "my book")
+      b = Book.find_or_create_by(name: "my other book")
+
+      assert_equal("my book", a.name)
+      assert_equal("my other book", b.name)
+    end
+
+    #End
+
+    def test_statement_cache_with_simple_statement
+      cache = ActiveRecord::StatementCache.create(Book.connection) do |params|
+        Book.where(name: "my book").where("author_id > 3")
+      end
+
+      Book.create(name: "my book", author_id: 4)
+
+      books = cache.execute([], Book, Book.connection)
+      assert_equal "my book", books[0].name
+    end
+
+    def test_statement_cache_with_complex_statement
+      cache = ActiveRecord::StatementCache.create(Book.connection) do |params|
+        Liquid.joins(:molecules => :electrons).where('molecules.name' => 'dioxane', 'electrons.name' => 'lepton')
+      end
+
+      salty = Liquid.create(name: 'salty')
+      molecule = salty.molecules.create(name: 'dioxane')
+      molecule.electrons.create(name: 'lepton')
+
+      liquids = cache.execute([], Book, Book.connection)
+      assert_equal "salty", liquids[0].name
+    end
+
+    def test_statement_cache_values_differ
+      cache = ActiveRecord::StatementCache.create(Book.connection) do |params|
+        Book.where(name: "my book")
+      end
+
+      3.times do
+        Book.create(name: "my book")
+      end
+
+      first_books = cache.execute([], Book, Book.connection)
+
+      3.times do
+        Book.create(name: "my book")
+      end
+
+      additional_books = cache.execute([], Book, Book.connection)
+      assert first_books != additional_books
+    end
+  end
+end
diff --git a/activerecord/test/cases/store_test.rb b/activerecord/test/cases/store_test.rb
new file mode 100644
index 0000000000..e9cdf94c99
--- /dev/null
+++ b/activerecord/test/cases/store_test.rb
@@ -0,0 +1,194 @@
+require 'cases/helper'
+require 'models/admin'
+require 'models/admin/user'
+
+class StoreTest < ActiveRecord::TestCase
+  fixtures :'admin/users'
+
+  setup do
+    @john = Admin::User.create!(:name => 'John Doe', :color => 'black', :remember_login => true, :height => 'tall', :is_a_good_guy => true)
+  end
+
+  test "reading store attributes through accessors" do
+    assert_equal 'black', @john.color
+    assert_nil @john.homepage
+  end
+
+  test "writing store attributes through accessors" do
+    @john.color = 'red'
+    @john.homepage = '37signals.com'
+
+    assert_equal 'red', @john.color
+    assert_equal '37signals.com', @john.homepage
+  end
+
+  test "accessing attributes not exposed by accessors" do
+    @john.settings[:icecream] = 'graeters'
+    @john.save
+
+    assert_equal 'graeters', @john.reload.settings[:icecream]
+  end
+
+  test "overriding a read accessor" do
+    @john.settings[:phone_number] = '1234567890'
+
+    assert_equal '(123) 456-7890', @john.phone_number
+  end
+
+  test "overriding a read accessor using super" do
+    @john.settings[:color] = nil
+
+    assert_equal 'red', @john.color
+  end
+
+  test "updating the store will mark it as changed" do
+    @john.color = 'red'
+    assert @john.settings_changed?
+  end
+
+  test "updating the store populates the changed array correctly" do
+    @john.color = 'red'
+    assert_equal 'black', @john.settings_change[0]['color']
+    assert_equal 'red', @john.settings_change[1]['color']
+  end
+
+  test "updating the store won't mark it as changed if an attribute isn't changed" do
+    @john.color = @john.color
+    assert !@john.settings_changed?
+  end
+
+  test "object initialization with not nullable column" do
+    assert_equal true, @john.remember_login
+  end
+
+  test "writing with not nullable column" do
+    @john.remember_login = false
+    assert_equal false, @john.remember_login
+  end
+
+  test "overriding a write accessor" do
+    @john.phone_number = '(123) 456-7890'
+
+    assert_equal '1234567890', @john.settings[:phone_number]
+  end
+
+  test "overriding a write accessor using super" do
+    @john.color = 'yellow'
+
+    assert_equal 'blue', @john.color
+  end
+
+  test "preserve store attributes data in HashWithIndifferentAccess format without any conversion" do
+    @john.json_data = ActiveSupport::HashWithIndifferentAccess.new(:height => 'tall', 'weight' => 'heavy')
+    @john.height = 'low'
+    assert_equal true, @john.json_data.instance_of?(ActiveSupport::HashWithIndifferentAccess)
+    assert_equal 'low', @john.json_data[:height]
+    assert_equal 'low', @john.json_data['height']
+    assert_equal 'heavy', @john.json_data[:weight]
+    assert_equal 'heavy', @john.json_data['weight']
+  end
+
+  test "convert store attributes from Hash to HashWithIndifferentAccess saving the data and access attributes indifferently" do
+    user = Admin::User.find_by_name('Jamis')
+    assert_equal 'symbol',  user.settings[:symbol]
+    assert_equal 'symbol',  user.settings['symbol']
+    assert_equal 'string',  user.settings[:string]
+    assert_equal 'string',  user.settings['string']
+    assert_equal true,      user.settings.instance_of?(ActiveSupport::HashWithIndifferentAccess)
+
+    user.height = 'low'
+    assert_equal 'symbol',  user.settings[:symbol]
+    assert_equal 'symbol',  user.settings['symbol']
+    assert_equal 'string',  user.settings[:string]
+    assert_equal 'string',  user.settings['string']
+    assert_equal true,      user.settings.instance_of?(ActiveSupport::HashWithIndifferentAccess)
+  end
+
+  test "convert store attributes from any format other than Hash or HashWithIndifferent access losing the data" do
+    @john.json_data = "somedata"
+    @john.height = 'low'
+    assert_equal true, @john.json_data.instance_of?(ActiveSupport::HashWithIndifferentAccess)
+    assert_equal 'low', @john.json_data[:height]
+    assert_equal 'low', @john.json_data['height']
+    assert_equal false, @john.json_data.delete_if { |k, v| k == 'height' }.any?
+  end
+
+  test "reading store attributes through accessors encoded with JSON" do
+    assert_equal 'tall', @john.height
+    assert_nil @john.weight
+  end
+
+  test "writing store attributes through accessors encoded with JSON" do
+    @john.height = 'short'
+    @john.weight = 'heavy'
+
+    assert_equal 'short', @john.height
+    assert_equal 'heavy', @john.weight
+  end
+
+  test "accessing attributes not exposed by accessors encoded with JSON" do
+    @john.json_data['somestuff'] = 'somecoolstuff'
+    @john.save
+
+    assert_equal 'somecoolstuff', @john.reload.json_data['somestuff']
+  end
+
+  test "updating the store will mark it as changed encoded with JSON" do
+    @john.height = 'short'
+    assert @john.json_data_changed?
+  end
+
+  test "object initialization with not nullable column encoded with JSON" do
+    assert_equal true, @john.is_a_good_guy
+  end
+
+  test "writing with not nullable column encoded with JSON" do
+    @john.is_a_good_guy = false
+    assert_equal false, @john.is_a_good_guy
+  end
+
+  test "all stored attributes are returned" do
+    assert_equal [:color, :homepage, :favorite_food], Admin::User.stored_attributes[:settings]
+  end
+
+  test "stored_attributes are tracked per class" do
+    first_model = Class.new(ActiveRecord::Base) do
+      store_accessor :data, :color
+    end
+    second_model = Class.new(ActiveRecord::Base) do
+      store_accessor :data, :width, :height
+    end
+
+    assert_equal [:color], first_model.stored_attributes[:data]
+    assert_equal [:width, :height], second_model.stored_attributes[:data]
+  end
+
+  test "stored_attributes are tracked per subclass" do
+    first_model = Class.new(ActiveRecord::Base) do
+      store_accessor :data, :color
+    end
+    second_model = Class.new(first_model) do
+      store_accessor :data, :width, :height
+    end
+    third_model = Class.new(first_model) do
+      store_accessor :data, :area, :volume
+    end
+
+    assert_equal [:color], first_model.stored_attributes[:data]
+    assert_equal [:color, :width, :height], second_model.stored_attributes[:data]
+    assert_equal [:color, :area, :volume], third_model.stored_attributes[:data]
+  end
+
+  test "YAML coder initializes the store when a Nil value is given" do
+    assert_equal({}, @john.params)
+  end
+
+  test "dump, load and dump again a model" do
+    dumped = YAML.dump(@john)
+    loaded = YAML.load(dumped)
+    assert_equal @john, loaded
+
+    second_dump = YAML.dump(loaded)
+    assert_equal @john, YAML.load(second_dump)
+  end
+end
diff --git a/activerecord/test/cases/tasks/database_tasks_test.rb b/activerecord/test/cases/tasks/database_tasks_test.rb
new file mode 100644
index 0000000000..01d373b691
--- /dev/null
+++ b/activerecord/test/cases/tasks/database_tasks_test.rb
@@ -0,0 +1,379 @@
+require 'cases/helper'
+require 'active_record/tasks/database_tasks'
+
+module ActiveRecord
+  module DatabaseTasksSetupper
+    def setup
+      @mysql_tasks, @postgresql_tasks, @sqlite_tasks = stub, stub, stub
+      ActiveRecord::Tasks::MySQLDatabaseTasks.stubs(:new).returns @mysql_tasks
+      ActiveRecord::Tasks::PostgreSQLDatabaseTasks.stubs(:new).returns @postgresql_tasks
+      ActiveRecord::Tasks::SQLiteDatabaseTasks.stubs(:new).returns @sqlite_tasks
+    end
+  end
+
+  ADAPTERS_TASKS = {
+    mysql:      :mysql_tasks,
+    mysql2:     :mysql_tasks,
+    postgresql: :postgresql_tasks,
+    sqlite3:    :sqlite_tasks
+  }
+
+  class DatabaseTasksRegisterTask < ActiveRecord::TestCase
+    def test_register_task
+      klazz = Class.new do
+        def initialize(*arguments); end
+        def structure_dump(filename); end
+      end
+      instance = klazz.new
+
+      klazz.stubs(:new).returns instance
+      instance.expects(:structure_dump).with("awesome-file.sql")
+
+      ActiveRecord::Tasks::DatabaseTasks.register_task(/foo/, klazz)
+      ActiveRecord::Tasks::DatabaseTasks.structure_dump({'adapter' => :foo}, "awesome-file.sql")
+    end
+
+    def test_unregistered_task
+      assert_raise(ActiveRecord::Tasks::DatabaseNotSupported) do
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump({'adapter' => :bar}, "awesome-file.sql")
+      end
+    end
+  end
+
+  class DatabaseTasksCreateTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_create") do
+        eval("@#{v}").expects(:create)
+        ActiveRecord::Tasks::DatabaseTasks.create 'adapter' => k
+      end
+    end
+  end
+
+  class DatabaseTasksCreateAllTest < ActiveRecord::TestCase
+    def setup
+      @configurations = {'development' => {'database' => 'my-db'}}
+
+      ActiveRecord::Base.stubs(:configurations).returns(@configurations)
+    end
+
+    def test_ignores_configurations_without_databases
+      @configurations['development'].merge!('database' => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).never
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_ignores_remote_databases
+      @configurations['development'].merge!('host' => 'my.server.tld')
+      $stderr.stubs(:puts).returns(nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).never
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_warning_for_remote_databases
+      @configurations['development'].merge!('host' => 'my.server.tld')
+
+      $stderr.expects(:puts).with('This task only modifies local databases. my-db is on a remote host.')
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_creates_configurations_with_local_ip
+      @configurations['development'].merge!('host' => '127.0.0.1')
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_creates_configurations_with_local_host
+      @configurations['development'].merge!('host' => 'localhost')
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
+    def test_creates_configurations_with_blank_hosts
+      @configurations['development'].merge!('host' => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+  end
+
+  class DatabaseTasksCreateCurrentTest < ActiveRecord::TestCase
+    def setup
+      @configurations = {
+        'development' => {'database' => 'dev-db'},
+        'test'        => {'database' => 'test-db'},
+        'production'  => {'database' => 'prod-db'}
+      }
+
+      ActiveRecord::Base.stubs(:configurations).returns(@configurations)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_creates_current_environment_database
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with('database' => 'prod-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.create_current(
+        ActiveSupport::StringInquirer.new('production')
+      )
+    end
+
+    def test_creates_test_and_development_databases_when_env_was_not_specified
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with('database' => 'dev-db')
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with('database' => 'test-db')
+      ENV.expects(:[]).with('RAILS_ENV').returns(nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_current(
+        ActiveSupport::StringInquirer.new('development')
+      )
+    end
+
+    def test_creates_only_development_database_when_rails_env_is_development
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).
+        with('database' => 'dev-db')
+      ENV.expects(:[]).with('RAILS_ENV').returns('development')
+
+      ActiveRecord::Tasks::DatabaseTasks.create_current(
+        ActiveSupport::StringInquirer.new('development')
+      )
+    end
+
+    def test_establishes_connection_for_the_given_environment
+      ActiveRecord::Tasks::DatabaseTasks.stubs(:create).returns true
+
+      ActiveRecord::Base.expects(:establish_connection).with(:development)
+
+      ActiveRecord::Tasks::DatabaseTasks.create_current(
+        ActiveSupport::StringInquirer.new('development')
+      )
+    end
+  end
+
+  class DatabaseTasksDropTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_drop") do
+        eval("@#{v}").expects(:drop)
+        ActiveRecord::Tasks::DatabaseTasks.drop 'adapter' => k
+      end
+    end
+  end
+
+  class DatabaseTasksDropAllTest < ActiveRecord::TestCase
+    def setup
+      @configurations = {:development => {'database' => 'my-db'}}
+
+      ActiveRecord::Base.stubs(:configurations).returns(@configurations)
+    end
+
+    def test_ignores_configurations_without_databases
+      @configurations[:development].merge!('database' => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).never
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_ignores_remote_databases
+      @configurations[:development].merge!('host' => 'my.server.tld')
+      $stderr.stubs(:puts).returns(nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).never
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_warning_for_remote_databases
+      @configurations[:development].merge!('host' => 'my.server.tld')
+
+      $stderr.expects(:puts).with('This task only modifies local databases. my-db is on a remote host.')
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_drops_configurations_with_local_ip
+      @configurations[:development].merge!('host' => '127.0.0.1')
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop)
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_drops_configurations_with_local_host
+      @configurations[:development].merge!('host' => 'localhost')
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop)
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
+    def test_drops_configurations_with_blank_hosts
+      @configurations[:development].merge!('host' => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop)
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+  end
+
+  class DatabaseTasksDropCurrentTest < ActiveRecord::TestCase
+    def setup
+      @configurations = {
+        'development' => {'database' => 'dev-db'},
+        'test'        => {'database' => 'test-db'},
+        'production'  => {'database' => 'prod-db'}
+      }
+
+      ActiveRecord::Base.stubs(:configurations).returns(@configurations)
+    end
+
+    def test_drops_current_environment_database
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with('database' => 'prod-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_current(
+        ActiveSupport::StringInquirer.new('production')
+      )
+    end
+
+    def test_drops_test_and_development_databases_when_env_was_not_specified
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with('database' => 'dev-db')
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with('database' => 'test-db')
+      ENV.expects(:[]).with('RAILS_ENV').returns(nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_current(
+        ActiveSupport::StringInquirer.new('development')
+      )
+    end
+
+    def test_drops_only_development_database_when_rails_env_is_development
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).
+        with('database' => 'dev-db')
+      ENV.expects(:[]).with('RAILS_ENV').returns('development')
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_current(
+        ActiveSupport::StringInquirer.new('development')
+      )
+    end
+  end
+
+  class DatabaseTasksMigrateTest < ActiveRecord::TestCase
+    def test_migrate_receives_correct_env_vars
+      verbose, version = ENV['VERBOSE'], ENV['VERSION']
+
+      ENV['VERBOSE'] = 'false'
+      ENV['VERSION'] = '4'
+
+      ActiveRecord::Migrator.expects(:migrate).with(ActiveRecord::Migrator.migrations_paths, 4)
+      ActiveRecord::Tasks::DatabaseTasks.migrate
+    ensure
+      ENV['VERBOSE'], ENV['VERSION'] = verbose, version
+    end
+  end
+
+  class DatabaseTasksPurgeTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_purge") do
+        eval("@#{v}").expects(:purge)
+        ActiveRecord::Tasks::DatabaseTasks.purge 'adapter' => k
+      end
+    end
+  end
+
+  class DatabaseTasksPurgeCurrentTest < ActiveRecord::TestCase
+    def test_purges_current_environment_database
+      configurations = {
+        'development' => {'database' => 'dev-db'},
+        'test'        => {'database' => 'test-db'},
+        'production'  => {'database' => 'prod-db'}
+      }
+      ActiveRecord::Base.stubs(:configurations).returns(configurations)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:purge).
+        with('database' => 'prod-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.purge_current('production')
+    end
+  end
+
+  class DatabaseTasksPurgeAllTest < ActiveRecord::TestCase
+    def test_purge_all_local_configurations
+      configurations = {:development => {'database' => 'my-db'}}
+      ActiveRecord::Base.stubs(:configurations).returns(configurations)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:purge).
+        with('database' => 'my-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.purge_all
+    end
+  end
+
+  class DatabaseTasksCharsetTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_charset") do
+        eval("@#{v}").expects(:charset)
+        ActiveRecord::Tasks::DatabaseTasks.charset 'adapter' => k
+      end
+    end
+  end
+
+  class DatabaseTasksCollationTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_collation") do
+        eval("@#{v}").expects(:collation)
+        ActiveRecord::Tasks::DatabaseTasks.collation 'adapter' => k
+      end
+    end
+  end
+
+  class DatabaseTasksStructureDumpTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_structure_dump") do
+        eval("@#{v}").expects(:structure_dump).with("awesome-file.sql")
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump({'adapter' => k}, "awesome-file.sql")
+      end
+    end
+  end
+
+  class DatabaseTasksStructureLoadTest < ActiveRecord::TestCase
+    include DatabaseTasksSetupper
+
+    ADAPTERS_TASKS.each do |k, v|
+      define_method("test_#{k}_structure_load") do
+        eval("@#{v}").expects(:structure_load).with("awesome-file.sql")
+        ActiveRecord::Tasks::DatabaseTasks.structure_load({'adapter' => k}, "awesome-file.sql")
+      end
+    end
+  end
+
+  class DatabaseTasksCheckSchemaFileTest < ActiveRecord::TestCase
+    def test_check_schema_file
+      Kernel.expects(:abort).with(regexp_matches(/awesome-file.sql/))
+      ActiveRecord::Tasks::DatabaseTasks.check_schema_file("awesome-file.sql")
+    end
+  end
+end
diff --git a/activerecord/test/cases/tasks/mysql_rake_test.rb b/activerecord/test/cases/tasks/mysql_rake_test.rb
new file mode 100644
index 0000000000..f58535f044
--- /dev/null
+++ b/activerecord/test/cases/tasks/mysql_rake_test.rb
@@ -0,0 +1,311 @@
+require 'cases/helper'
+
+if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+module ActiveRecord
+  class MysqlDBCreateTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:create_database => true)
+      @configuration = {
+        'adapter'  => 'mysql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_establishes_connection_without_database
+      ActiveRecord::Base.expects(:establish_connection).
+        with('adapter' => 'mysql', 'database' => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+
+    def test_creates_database_with_default_encoding_and_collation
+      @connection.expects(:create_database).
+        with('my-app-db', charset: 'utf8', collation: 'utf8_unicode_ci')
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+
+    def test_creates_database_with_given_encoding_and_default_collation
+      @connection.expects(:create_database).
+        with('my-app-db', charset: 'utf8', collation: 'utf8_unicode_ci')
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration.merge('encoding' => 'utf8')
+    end
+
+    def test_creates_database_with_given_encoding_and_no_collation
+      @connection.expects(:create_database).
+        with('my-app-db', charset: 'latin1')
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration.merge('encoding' => 'latin1')
+    end
+
+    def test_creates_database_with_given_collation_and_no_encoding
+      @connection.expects(:create_database).
+        with('my-app-db', collation: 'latin1_swedish_ci')
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration.merge('collation' => 'latin1_swedish_ci')
+    end
+
+    def test_establishes_connection_to_database
+      ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+
+    def test_create_when_database_exists_outputs_info_to_stderr
+      $stderr.expects(:puts).with("my-app-db already exists").once
+
+      ActiveRecord::Base.connection.stubs(:create_database).raises(
+        ActiveRecord::StatementInvalid.new("Can't create database 'dev'; database exists:")
+      )
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+  end
+
+  if current_adapter?(:MysqlAdapter)
+    class MysqlDBCreateAsRootTest < ActiveRecord::TestCase
+      def setup
+        @connection    = stub("Connection", create_database: true)
+        @error         = Mysql::Error.new "Invalid permissions"
+        @configuration = {
+          'adapter'  => 'mysql',
+          'database' => 'my-app-db',
+          'username' => 'pat',
+          'password' => 'wossname'
+        }
+
+        $stdin.stubs(:gets).returns("secret\n")
+        $stdout.stubs(:print).returns(nil)
+        @error.stubs(:errno).returns(1045)
+        ActiveRecord::Base.stubs(:connection).returns(@connection)
+        ActiveRecord::Base.stubs(:establish_connection).
+          raises(@error).
+          then.returns(true)
+      end
+
+      if defined?(::Mysql)
+        def test_root_password_is_requested
+          assert_permissions_granted_for "pat"
+          $stdin.expects(:gets).returns("secret\n")
+
+          ActiveRecord::Tasks::DatabaseTasks.create @configuration
+        end
+      end
+
+      def test_connection_established_as_root
+        assert_permissions_granted_for "pat"
+        ActiveRecord::Base.expects(:establish_connection).with(
+          'adapter'  => 'mysql',
+          'database' => nil,
+          'username' => 'root',
+          'password' => 'secret'
+        )
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_database_created_by_root
+        assert_permissions_granted_for "pat"
+        @connection.expects(:create_database).
+          with('my-app-db', :charset => 'utf8', :collation => 'utf8_unicode_ci')
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_grant_privileges_for_normal_user
+        assert_permissions_granted_for "pat"
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_do_not_grant_privileges_for_root_user
+        @configuration['username'] = 'root'
+        @configuration['password'] = ''
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_connection_established_as_normal_user
+        assert_permissions_granted_for "pat"
+        ActiveRecord::Base.expects(:establish_connection).returns do
+          ActiveRecord::Base.expects(:establish_connection).with(
+            'adapter'  => 'mysql',
+            'database' => 'my-app-db',
+            'username' => 'pat',
+            'password' => 'secret'
+          )
+
+          raise @error
+        end
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      def test_sends_output_to_stderr_when_other_errors
+        @error.stubs(:errno).returns(42)
+
+        $stderr.expects(:puts).at_least_once.returns(nil)
+
+        ActiveRecord::Tasks::DatabaseTasks.create @configuration
+      end
+
+      private
+        def assert_permissions_granted_for(db_user)
+          db_name = @configuration['database']
+          db_password = @configuration['password']
+          @connection.expects(:execute).with("GRANT ALL PRIVILEGES ON #{db_name}.* TO '#{db_user}'@'localhost' IDENTIFIED BY '#{db_password}' WITH GRANT OPTION;")
+        end
+    end
+  end
+
+  class MySQLDBDropTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:drop_database => true)
+      @configuration = {
+        'adapter'  => 'mysql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_establishes_connection_to_mysql_database
+      ActiveRecord::Base.expects(:establish_connection).with @configuration
+
+      ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+    end
+
+    def test_drops_database
+      @connection.expects(:drop_database).with('my-app-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+    end
+  end
+
+  class MySQLPurgeTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:recreate_database => true)
+      @configuration = {
+        'adapter'  => 'mysql',
+        'database' => 'test-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_establishes_connection_to_the_appropriate_database
+      ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+      ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+    end
+
+    def test_recreates_database_with_the_default_options
+      @connection.expects(:recreate_database).
+        with('test-db', charset: 'utf8', collation: 'utf8_unicode_ci')
+
+      ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+    end
+
+    def test_recreates_database_with_the_given_options
+      @connection.expects(:recreate_database).
+        with('test-db', charset: 'latin', collation: 'latin1_swedish_ci')
+
+      ActiveRecord::Tasks::DatabaseTasks.purge @configuration.merge(
+        'encoding' => 'latin', 'collation' => 'latin1_swedish_ci')
+    end
+  end
+
+  class MysqlDBCharsetTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:create_database => true)
+      @configuration = {
+        'adapter'  => 'mysql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_db_retrieves_charset
+      @connection.expects(:charset)
+      ActiveRecord::Tasks::DatabaseTasks.charset @configuration
+    end
+  end
+
+  class MysqlDBCollationTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:create_database => true)
+      @configuration = {
+        'adapter'  => 'mysql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_db_retrieves_collation
+      @connection.expects(:collation)
+      ActiveRecord::Tasks::DatabaseTasks.collation @configuration
+    end
+  end
+
+  class MySQLStructureDumpTest < ActiveRecord::TestCase
+    def setup
+      @configuration = {
+        'adapter'  => 'mysql',
+        'database' => 'test-db'
+      }
+    end
+
+    def test_structure_dump
+      filename = "awesome-file.sql"
+      Kernel.expects(:system).with("mysqldump", "--result-file", filename, "--no-data", "test-db").returns(true)
+
+      ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
+    end
+
+    def test_warn_when_external_structure_dump_fails
+      filename = "awesome-file.sql"
+      Kernel.expects(:system).with("mysqldump", "--result-file", filename, "--no-data", "test-db").returns(false)
+
+      warnings = capture(:stderr) do
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
+      end
+
+      assert_match(/Could not dump the database structure/, warnings)
+    end
+
+    def test_structure_dump_with_port_number
+      filename = "awesome-file.sql"
+      Kernel.expects(:system).with("mysqldump", "--port", "10000", "--result-file", filename, "--no-data", "test-db").returns(true)
+
+      ActiveRecord::Tasks::DatabaseTasks.structure_dump(
+        @configuration.merge('port' => 10000),
+        filename)
+    end
+  end
+
+  class MySQLStructureLoadTest < ActiveRecord::TestCase
+    def setup
+      @configuration = {
+        'adapter'  => 'mysql',
+        'database' => 'test-db'
+      }
+    end
+
+    def test_structure_load
+      filename = "awesome-file.sql"
+      Kernel.expects(:system).with('mysql', '--execute', %{SET FOREIGN_KEY_CHECKS = 0; SOURCE #{filename}; SET FOREIGN_KEY_CHECKS = 1}, "--database", "test-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
+    end
+  end
+
+end
+end
diff --git a/activerecord/test/cases/tasks/postgresql_rake_test.rb b/activerecord/test/cases/tasks/postgresql_rake_test.rb
new file mode 100644
index 0000000000..0d574d071c
--- /dev/null
+++ b/activerecord/test/cases/tasks/postgresql_rake_test.rb
@@ -0,0 +1,245 @@
+require 'cases/helper'
+
+if current_adapter?(:PostgreSQLAdapter)
+module ActiveRecord
+  class PostgreSQLDBCreateTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:create_database => true)
+      @configuration = {
+        'adapter'  => 'postgresql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_establishes_connection_to_postgresql_database
+      ActiveRecord::Base.expects(:establish_connection).with(
+        'adapter'            => 'postgresql',
+        'database'           => 'postgres',
+        'schema_search_path' => 'public'
+      )
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+
+    def test_creates_database_with_default_encoding
+      @connection.expects(:create_database).
+        with('my-app-db', @configuration.merge('encoding' => 'utf8'))
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+
+    def test_creates_database_with_given_encoding
+      @connection.expects(:create_database).
+        with('my-app-db', @configuration.merge('encoding' => 'latin'))
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration.
+        merge('encoding' => 'latin')
+    end
+
+    def test_creates_database_with_given_collation_and_ctype
+      @connection.expects(:create_database).
+        with('my-app-db', @configuration.merge('encoding' => 'utf8', 'collation' => 'ja_JP.UTF8', 'ctype' => 'ja_JP.UTF8'))
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration.
+        merge('collation' => 'ja_JP.UTF8', 'ctype' => 'ja_JP.UTF8')
+    end
+
+    def test_establishes_connection_to_new_database
+      ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+
+    def test_db_create_with_error_prints_message
+      ActiveRecord::Base.stubs(:establish_connection).raises(Exception)
+
+      $stderr.stubs(:puts).returns(true)
+      $stderr.expects(:puts).
+        with("Couldn't create database for #{@configuration.inspect}")
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+
+    def test_create_when_database_exists_outputs_info_to_stderr
+      $stderr.expects(:puts).with("my-app-db already exists").once
+
+      ActiveRecord::Base.connection.stubs(:create_database).raises(
+        ActiveRecord::StatementInvalid.new('database "my-app-db" already exists')
+      )
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
+  end
+
+  class PostgreSQLDBDropTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:drop_database => true)
+      @configuration = {
+        'adapter'  => 'postgresql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_establishes_connection_to_postgresql_database
+      ActiveRecord::Base.expects(:establish_connection).with(
+        'adapter'            => 'postgresql',
+        'database'           => 'postgres',
+        'schema_search_path' => 'public'
+      )
+
+      ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+    end
+
+    def test_drops_database
+      @connection.expects(:drop_database).with('my-app-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+    end
+  end
+
+  class PostgreSQLPurgeTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:create_database => true, :drop_database => true)
+      @configuration = {
+        'adapter'  => 'postgresql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:clear_active_connections!).returns(true)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_clears_active_connections
+      ActiveRecord::Base.expects(:clear_active_connections!)
+
+      ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+    end
+
+    def test_establishes_connection_to_postgresql_database
+      ActiveRecord::Base.expects(:establish_connection).with(
+        'adapter'            => 'postgresql',
+        'database'           => 'postgres',
+        'schema_search_path' => 'public'
+      )
+
+      ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+    end
+
+    def test_drops_database
+      @connection.expects(:drop_database).with('my-app-db')
+
+      ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+    end
+
+    def test_creates_database
+      @connection.expects(:create_database).
+        with('my-app-db', @configuration.merge('encoding' => 'utf8'))
+
+      ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+    end
+
+    def test_establishes_connection
+      ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+      ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+    end
+  end
+
+  class PostgreSQLDBCharsetTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:create_database => true)
+      @configuration = {
+        'adapter'  => 'postgresql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_db_retrieves_charset
+      @connection.expects(:encoding)
+      ActiveRecord::Tasks::DatabaseTasks.charset @configuration
+    end
+  end
+
+  class PostgreSQLDBCollationTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:create_database => true)
+      @configuration = {
+        'adapter'  => 'postgresql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_db_retrieves_collation
+      @connection.expects(:collation)
+      ActiveRecord::Tasks::DatabaseTasks.collation @configuration
+    end
+  end
+
+  class PostgreSQLStructureDumpTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub(:structure_dump => true)
+      @configuration = {
+        'adapter'  => 'postgresql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      Kernel.stubs(:system)
+    end
+
+    def test_structure_dump
+      filename = "awesome-file.sql"
+      Kernel.expects(:system).with("pg_dump -i -s -x -O -f #{filename}  my-app-db").returns(true)
+      @connection.expects(:schema_search_path).returns("foo")
+
+      ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
+      assert File.exist?(filename)
+    ensure
+      FileUtils.rm(filename)
+    end
+  end
+
+  class PostgreSQLStructureLoadTest < ActiveRecord::TestCase
+    def setup
+      @connection    = stub
+      @configuration = {
+        'adapter'  => 'postgresql',
+        'database' => 'my-app-db'
+      }
+
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+      Kernel.stubs(:system)
+    end
+
+    def test_structure_load
+      filename = "awesome-file.sql"
+      Kernel.expects(:system).with("psql -q -f #{filename} my-app-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
+    end
+
+    def test_structure_load_accepts_path_with_spaces
+      filename = "awesome file.sql"
+      Kernel.expects(:system).with("psql -q -f awesome\\ file.sql my-app-db")
+
+      ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
+    end
+  end
+
+end
+end
diff --git a/activerecord/test/cases/tasks/sqlite_rake_test.rb b/activerecord/test/cases/tasks/sqlite_rake_test.rb
new file mode 100644
index 0000000000..750d5e42dc
--- /dev/null
+++ b/activerecord/test/cases/tasks/sqlite_rake_test.rb
@@ -0,0 +1,193 @@
+require 'cases/helper'
+require 'pathname'
+
+if current_adapter?(:SQLite3Adapter)
+module ActiveRecord
+  class SqliteDBCreateTest < ActiveRecord::TestCase
+    def setup
+      @database      = 'db_create.sqlite3'
+      @connection    = stub :connection
+      @configuration = {
+        'adapter'  => 'sqlite3',
+        'database' => @database
+      }
+
+      File.stubs(:exist?).returns(false)
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_db_checks_database_exists
+      File.expects(:exist?).with(@database).returns(false)
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration, '/rails/root'
+    end
+
+    def test_db_create_when_file_exists
+      File.stubs(:exist?).returns(true)
+
+      $stderr.expects(:puts).with("#{@database} already exists")
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration, '/rails/root'
+    end
+
+    def test_db_create_with_file_does_nothing
+      File.stubs(:exist?).returns(true)
+      $stderr.stubs(:puts).returns(nil)
+
+      ActiveRecord::Base.expects(:establish_connection).never
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration, '/rails/root'
+    end
+
+    def test_db_create_establishes_a_connection
+      ActiveRecord::Base.expects(:establish_connection).with(@configuration)
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration, '/rails/root'
+    end
+
+    def test_db_create_with_error_prints_message
+      ActiveRecord::Base.stubs(:establish_connection).raises(Exception)
+
+      $stderr.stubs(:puts).returns(true)
+      $stderr.expects(:puts).
+        with("Couldn't create database for #{@configuration.inspect}")
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration, '/rails/root'
+    end
+  end
+
+  class SqliteDBDropTest < ActiveRecord::TestCase
+    def setup
+      @database      = "db_create.sqlite3"
+      @path          = stub(:to_s => '/absolute/path', :absolute? => true)
+      @configuration = {
+        'adapter'  => 'sqlite3',
+        'database' => @database
+      }
+
+      Pathname.stubs(:new).returns(@path)
+      File.stubs(:join).returns('/former/relative/path')
+      FileUtils.stubs(:rm).returns(true)
+    end
+
+    def test_creates_path_from_database
+      Pathname.expects(:new).with(@database).returns(@path)
+
+      ActiveRecord::Tasks::DatabaseTasks.drop @configuration, '/rails/root'
+    end
+
+    def test_removes_file_with_absolute_path
+      File.stubs(:exist?).returns(true)
+      @path.stubs(:absolute?).returns(true)
+
+      FileUtils.expects(:rm).with('/absolute/path')
+
+      ActiveRecord::Tasks::DatabaseTasks.drop @configuration, '/rails/root'
+    end
+
+    def test_generates_absolute_path_with_given_root
+      @path.stubs(:absolute?).returns(false)
+
+      File.expects(:join).with('/rails/root', @path).
+        returns('/former/relative/path')
+
+      ActiveRecord::Tasks::DatabaseTasks.drop @configuration, '/rails/root'
+    end
+
+    def test_removes_file_with_relative_path
+      File.stubs(:exist?).returns(true)
+      @path.stubs(:absolute?).returns(false)
+
+      FileUtils.expects(:rm).with('/former/relative/path')
+
+      ActiveRecord::Tasks::DatabaseTasks.drop @configuration, '/rails/root'
+    end
+  end
+
+  class SqliteDBCharsetTest < ActiveRecord::TestCase
+    def setup
+      @database      = 'db_create.sqlite3'
+      @connection    = stub :connection
+      @configuration = {
+        'adapter'  => 'sqlite3',
+        'database' => @database
+      }
+
+      File.stubs(:exist?).returns(false)
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_db_retrieves_charset
+      @connection.expects(:encoding)
+      ActiveRecord::Tasks::DatabaseTasks.charset @configuration, '/rails/root'
+    end
+  end
+
+  class SqliteDBCollationTest < ActiveRecord::TestCase
+    def setup
+      @database      = 'db_create.sqlite3'
+      @connection    = stub :connection
+      @configuration = {
+        'adapter'  => 'sqlite3',
+        'database' => @database
+      }
+
+      File.stubs(:exist?).returns(false)
+      ActiveRecord::Base.stubs(:connection).returns(@connection)
+      ActiveRecord::Base.stubs(:establish_connection).returns(true)
+    end
+
+    def test_db_retrieves_collation
+      assert_raise NoMethodError do
+        ActiveRecord::Tasks::DatabaseTasks.collation @configuration, '/rails/root'
+      end
+    end
+  end
+
+  class SqliteStructureDumpTest < ActiveRecord::TestCase
+    def setup
+      @database      = "db_create.sqlite3"
+      @configuration = {
+        'adapter'  => 'sqlite3',
+        'database' => @database
+      }
+    end
+
+    def test_structure_dump
+      dbfile   = @database
+      filename = "awesome-file.sql"
+
+      ActiveRecord::Tasks::DatabaseTasks.structure_dump @configuration, filename, '/rails/root'
+      assert File.exist?(dbfile)
+      assert File.exist?(filename)
+    ensure
+      FileUtils.rm_f(filename)
+      FileUtils.rm_f(dbfile)
+    end
+  end
+
+  class SqliteStructureLoadTest < ActiveRecord::TestCase
+    def setup
+      @database      = "db_create.sqlite3"
+      @configuration = {
+        'adapter'  => 'sqlite3',
+        'database' => @database
+      }
+    end
+
+    def test_structure_load
+      dbfile   = @database
+      filename = "awesome-file.sql"
+
+      open(filename, 'w') { |f| f.puts("select datetime('now', 'localtime');") }
+      ActiveRecord::Tasks::DatabaseTasks.structure_load @configuration, filename, '/rails/root'
+      assert File.exist?(dbfile)
+    ensure
+      FileUtils.rm_f(filename)
+      FileUtils.rm_f(dbfile)
+    end
+  end
+end
+end
diff --git a/activerecord/test/cases/test_case.rb b/activerecord/test/cases/test_case.rb
new file mode 100644
index 0000000000..23a170388e
--- /dev/null
+++ b/activerecord/test/cases/test_case.rb
@@ -0,0 +1,123 @@
+require 'active_support/test_case'
+
+module ActiveRecord
+  # = Active Record Test Case
+  #
+  # Defines some test assertions to test against SQL queries.
+  class TestCase < ActiveSupport::TestCase #:nodoc:
+    def teardown
+      SQLCounter.clear_log
+    end
+
+    def assert_date_from_db(expected, actual, message = nil)
+      assert_equal expected.to_s, actual.to_s, message
+    end
+
+    def capture(stream)
+      stream = stream.to_s
+      captured_stream = Tempfile.new(stream)
+      stream_io = eval("$#{stream}")
+      origin_stream = stream_io.dup
+      stream_io.reopen(captured_stream)
+
+      yield
+
+      stream_io.rewind
+      return captured_stream.read
+    ensure
+      captured_stream.close
+      captured_stream.unlink
+      stream_io.reopen(origin_stream)
+    end
+
+    def capture_sql
+      SQLCounter.clear_log
+      yield
+      SQLCounter.log_all.dup
+    end
+
+    def assert_sql(*patterns_to_match)
+      capture_sql { yield }
+    ensure
+      failed_patterns = []
+      patterns_to_match.each do |pattern|
+        failed_patterns << pattern unless SQLCounter.log_all.any?{ |sql| pattern === sql }
+      end
+      assert failed_patterns.empty?, "Query pattern(s) #{failed_patterns.map{ |p| p.inspect }.join(', ')} not found.#{SQLCounter.log.size == 0 ? '' : "\nQueries:\n#{SQLCounter.log.join("\n")}"}"
+    end
+
+    def assert_queries(num = 1, options = {})
+      ignore_none = options.fetch(:ignore_none) { num == :any }
+      SQLCounter.clear_log
+      x = yield
+      the_log = ignore_none ? SQLCounter.log_all : SQLCounter.log
+      if num == :any
+        assert_operator the_log.size, :>=, 1, "1 or more queries expected, but none were executed."
+      else
+        mesg = "#{the_log.size} instead of #{num} queries were executed.#{the_log.size == 0 ? '' : "\nQueries:\n#{the_log.join("\n")}"}"
+        assert_equal num, the_log.size, mesg
+      end
+      x
+    end
+
+    def assert_no_queries(options = {}, &block)
+      options.reverse_merge! ignore_none: true
+      assert_queries(0, options, &block)
+    end
+
+    def assert_column(model, column_name, msg=nil)
+      assert has_column?(model, column_name), msg
+    end
+
+    def assert_no_column(model, column_name, msg=nil)
+      assert_not has_column?(model, column_name), msg
+    end
+
+    def has_column?(model, column_name)
+      model.reset_column_information
+      model.column_names.include?(column_name.to_s)
+    end
+  end
+
+  class SQLCounter
+    class << self
+      attr_accessor :ignored_sql, :log, :log_all
+      def clear_log; self.log = []; self.log_all = []; end
+    end
+
+    self.clear_log
+
+    self.ignored_sql = [/^PRAGMA/, /^SELECT currval/, /^SELECT CAST/, /^SELECT @@IDENTITY/, /^SELECT @@ROWCOUNT/, /^SAVEPOINT/, /^ROLLBACK TO SAVEPOINT/, /^RELEASE SAVEPOINT/, /^SHOW max_identifier_length/, /^BEGIN/, /^COMMIT/]
+
+    # FIXME: this needs to be refactored so specific database can add their own
+    # ignored SQL, or better yet, use a different notification for the queries
+    # instead examining the SQL content.
+    oracle_ignored     = [/^select .*nextval/i, /^SAVEPOINT/, /^ROLLBACK TO/, /^\s*select .* from all_triggers/im, /^\s*select .* from all_constraints/im, /^\s*select .* from all_tab_cols/im]
+    mysql_ignored      = [/^SHOW TABLES/i, /^SHOW FULL FIELDS/, /^SHOW CREATE TABLE /i]
+    postgresql_ignored = [/^\s*select\b.*\bfrom\b.*pg_namespace\b/im, /^\s*select\b.*\battname\b.*\bfrom\b.*\bpg_attribute\b/im, /^SHOW search_path/i]
+    sqlite3_ignored =    [/^\s*SELECT name\b.*\bFROM sqlite_master/im]
+
+    [oracle_ignored, mysql_ignored, postgresql_ignored, sqlite3_ignored].each do |db_ignored_sql|
+      ignored_sql.concat db_ignored_sql
+    end
+
+    attr_reader :ignore
+
+    def initialize(ignore = Regexp.union(self.class.ignored_sql))
+      @ignore = ignore
+    end
+
+    def call(name, start, finish, message_id, values)
+      sql = values[:sql]
+
+      # FIXME: this seems bad. we should probably have a better way to indicate
+      # the query was cached
+      return if 'CACHE' == values[:name]
+
+      self.class.log_all << sql
+      self.class.log << sql unless ignore =~ sql
+    end
+  end
+
+  ActiveSupport::Notifications.subscribe('sql.active_record', SQLCounter.new)
+end
diff --git a/activerecord/test/cases/timestamp_test.rb b/activerecord/test/cases/timestamp_test.rb
new file mode 100644
index 0000000000..0472246f71
--- /dev/null
+++ b/activerecord/test/cases/timestamp_test.rb
@@ -0,0 +1,426 @@
+require 'cases/helper'
+require 'models/developer'
+require 'models/owner'
+require 'models/pet'
+require 'models/toy'
+require 'models/car'
+require 'models/task'
+
+class TimestampTest < ActiveRecord::TestCase
+  fixtures :developers, :owners, :pets, :toys, :cars, :tasks
+
+  def setup
+    @developer = Developer.first
+    @owner = Owner.first
+    @developer.update_columns(updated_at: Time.now.prev_month)
+    @previously_updated_at = @developer.updated_at
+  end
+
+  def test_saving_a_changed_record_updates_its_timestamp
+    @developer.name = "Jack Bauer"
+    @developer.save!
+
+    assert_not_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_saving_a_unchanged_record_doesnt_update_its_timestamp
+    @developer.save!
+
+    assert_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_touching_a_record_updates_its_timestamp
+    previous_salary = @developer.salary
+    @developer.salary = previous_salary + 10000
+    @developer.touch
+
+    assert_not_equal @previously_updated_at, @developer.updated_at
+    assert_equal previous_salary + 10000, @developer.salary
+    assert @developer.salary_changed?, 'developer salary should have changed'
+    assert @developer.changed?, 'developer should be marked as changed'
+    @developer.reload
+    assert_equal previous_salary, @developer.salary
+  end
+
+  def test_touching_a_record_with_default_scope_that_excludes_it_updates_its_timestamp
+    developer = @developer.becomes(DeveloperCalledJamis)
+
+    developer.touch
+    assert_not_equal @previously_updated_at, developer.updated_at
+    developer.reload
+    assert_not_equal @previously_updated_at, developer.updated_at
+  end
+
+  def test_saving_when_record_timestamps_is_false_doesnt_update_its_timestamp
+    Developer.record_timestamps = false
+    @developer.name = "John Smith"
+    @developer.save!
+
+    assert_equal @previously_updated_at, @developer.updated_at
+  ensure
+    Developer.record_timestamps = true
+  end
+
+  def test_saving_when_instance_record_timestamps_is_false_doesnt_update_its_timestamp
+    @developer.record_timestamps = false
+    assert Developer.record_timestamps
+
+    @developer.name = "John Smith"
+    @developer.save!
+
+    assert_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_touching_an_attribute_updates_timestamp
+    previously_created_at = @developer.created_at
+    @developer.touch(:created_at)
+
+    assert !@developer.created_at_changed? , 'created_at should not be changed'
+    assert !@developer.changed?, 'record should not be changed'
+    assert_not_equal previously_created_at, @developer.created_at
+    assert_not_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_touching_an_attribute_updates_it
+    task = Task.first
+    previous_value = task.ending
+    task.touch(:ending)
+    assert_not_equal previous_value, task.ending
+    assert_in_delta Time.now, task.ending, 1
+  end
+
+  def test_touching_many_attributes_updates_them
+    task = Task.first
+    previous_starting = task.starting
+    previous_ending = task.ending
+    task.touch(:starting, :ending)
+
+    assert_not_equal previous_starting, task.starting
+    assert_not_equal previous_ending, task.ending
+    assert_in_delta Time.now, task.starting, 1
+    assert_in_delta Time.now, task.ending, 1
+  end
+
+  def test_touching_a_record_without_timestamps_is_unexceptional
+    assert_nothing_raised { Car.first.touch }
+  end
+
+  def test_touching_a_no_touching_object
+    Developer.no_touching do
+      assert @developer.no_touching?
+      assert !@owner.no_touching?
+      @developer.touch
+    end
+
+    assert !@developer.no_touching?
+    assert !@owner.no_touching?
+    assert_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_touching_related_objects
+    @owner = Owner.first
+    @previously_updated_at = @owner.updated_at
+
+    Owner.no_touching do
+      @owner.pets.first.touch
+    end
+
+    assert_equal @previously_updated_at, @owner.updated_at
+  end
+
+  def test_global_no_touching
+    ActiveRecord::Base.no_touching do
+      assert @developer.no_touching?
+      assert @owner.no_touching?
+      @developer.touch
+    end
+
+    assert !@developer.no_touching?
+    assert !@owner.no_touching?
+    assert_equal @previously_updated_at, @developer.updated_at
+  end
+
+  def test_no_touching_threadsafe
+    Thread.new do
+      Developer.no_touching do
+        assert @developer.no_touching?
+
+        sleep(1)
+      end
+    end
+
+    assert !@developer.no_touching?
+  end
+
+  def test_no_touching_with_callbacks
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "developers"
+
+      attr_accessor :after_touch_called
+
+      after_touch do |user|
+        user.after_touch_called = true
+      end
+    end
+
+    developer = klass.first
+
+    klass.no_touching do
+      developer.touch
+      assert_not developer.after_touch_called
+    end
+  end
+
+  def test_saving_a_record_with_a_belongs_to_that_specifies_touching_the_parent_should_update_the_parent_updated_at
+    pet   = Pet.first
+    owner = pet.owner
+    previously_owner_updated_at = owner.updated_at
+
+    pet.name = "Fluffy the Third"
+    pet.save
+
+    assert_not_equal previously_owner_updated_at, pet.owner.updated_at
+  end
+
+  def test_destroying_a_record_with_a_belongs_to_that_specifies_touching_the_parent_should_update_the_parent_updated_at
+    pet   = Pet.first
+    owner = pet.owner
+    previously_owner_updated_at = owner.updated_at
+
+    pet.destroy
+
+    assert_not_equal previously_owner_updated_at, pet.owner.updated_at
+  end
+
+  def test_saving_a_new_record_belonging_to_invalid_parent_with_touch_should_not_raise_exception
+    klass = Class.new(Owner) do
+      def self.name; 'Owner'; end
+      validate { errors.add(:base, :invalid) }
+    end
+
+    pet = Pet.new(owner: klass.new)
+    pet.save!
+
+    assert pet.owner.new_record?
+  end
+
+  def test_saving_a_record_with_a_belongs_to_that_specifies_touching_a_specific_attribute_the_parent_should_update_that_attribute
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Pet'; end
+      belongs_to :owner, :touch => :happy_at
+    end
+
+    pet   = klass.first
+    owner = pet.owner
+    previously_owner_happy_at = owner.happy_at
+
+    pet.name = "Fluffy the Third"
+    pet.save
+
+    assert_not_equal previously_owner_happy_at, pet.owner.happy_at
+  end
+
+  def test_touching_a_record_with_a_belongs_to_that_uses_a_counter_cache_should_update_the_parent
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Pet'; end
+      belongs_to :owner, :counter_cache => :use_count, :touch => true
+    end
+
+    pet = klass.first
+    owner = pet.owner
+    owner.update_columns(happy_at: 3.days.ago)
+    previously_owner_updated_at = owner.updated_at
+
+    pet.name = "I'm a parrot"
+    pet.save
+
+    assert_not_equal previously_owner_updated_at, pet.owner.updated_at
+  end
+
+  def test_touching_a_record_touches_parent_record_and_grandparent_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Toy'; end
+      belongs_to :pet, :touch => true
+    end
+
+    toy = klass.first
+    pet = toy.pet
+    owner = pet.owner
+    time = 3.days.ago
+
+    owner.update_columns(updated_at: time)
+    toy.touch
+    owner.reload
+
+    assert_not_equal time, owner.updated_at
+  end
+
+  def test_touching_a_record_touches_polymorphic_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Toy'; end
+    end
+
+    wheel_klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Wheel'; end
+      belongs_to :wheelable, :polymorphic => true, :touch => true
+    end
+
+    toy = klass.first
+    time = 3.days.ago
+    toy.update_columns(updated_at: time)
+
+    wheel = wheel_klass.new
+    wheel.wheelable = toy
+    wheel.save
+    wheel.touch
+
+    assert_not_equal time, toy.updated_at
+  end
+
+  def test_changing_parent_of_a_record_touches_both_new_and_old_parent_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Toy'; end
+      belongs_to :pet, touch: true
+    end
+
+    toy1 = klass.find(1)
+    old_pet = toy1.pet
+
+    toy2 = klass.find(2)
+    new_pet = toy2.pet
+    time = 3.days.ago.at_beginning_of_hour
+
+    old_pet.update_columns(updated_at: time)
+    new_pet.update_columns(updated_at: time)
+
+    toy1.pet = new_pet
+    toy1.save!
+
+    old_pet.reload
+    new_pet.reload
+
+    assert_not_equal time, new_pet.updated_at
+    assert_not_equal time, old_pet.updated_at
+  end
+
+  def test_changing_parent_of_a_record_touches_both_new_and_old_polymorphic_parent_record_changes_within_same_class
+    car_class = Class.new(ActiveRecord::Base) do
+      def self.name; 'Car'; end
+    end
+
+    wheel_class = Class.new(ActiveRecord::Base) do
+      def self.name; 'Wheel'; end
+      belongs_to :wheelable, :polymorphic => true, :touch => true
+    end
+
+    car1 = car_class.find(1)
+    car2 = car_class.find(2)
+
+    wheel = wheel_class.create!(wheelable: car1)
+
+    time = 3.days.ago.at_beginning_of_hour
+
+    car1.update_columns(updated_at: time)
+    car2.update_columns(updated_at: time)
+
+    wheel.wheelable = car2
+    wheel.save!
+
+    assert_not_equal time, car1.reload.updated_at
+    assert_not_equal time, car2.reload.updated_at
+  end
+
+  def test_changing_parent_of_a_record_touches_both_new_and_old_polymorphic_parent_record_changes_with_other_class
+    car_class = Class.new(ActiveRecord::Base) do
+      def self.name; 'Car'; end
+    end
+
+    toy_class = Class.new(ActiveRecord::Base) do
+      def self.name; 'Toy'; end
+    end
+
+    wheel_class = Class.new(ActiveRecord::Base) do
+      def self.name; 'Wheel'; end
+      belongs_to :wheelable, :polymorphic => true, :touch => true
+    end
+
+    car = car_class.find(1)
+    toy = toy_class.find(3)
+
+    wheel = wheel_class.create!(wheelable: car)
+
+    time = 3.days.ago.at_beginning_of_hour
+
+    car.update_columns(updated_at: time)
+    toy.update_columns(updated_at: time)
+
+    wheel.wheelable = toy
+    wheel.save!
+
+    assert_not_equal time, car.reload.updated_at
+    assert_not_equal time, toy.reload.updated_at
+  end
+
+  def test_clearing_association_touches_the_old_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Toy'; end
+      belongs_to :pet, touch: true
+    end
+
+    toy = klass.find(1)
+    pet = toy.pet
+    time = 3.days.ago.at_beginning_of_hour
+
+    pet.update_columns(updated_at: time)
+
+    toy.pet = nil
+    toy.save!
+
+    pet.reload
+
+    assert_not_equal time, pet.updated_at
+  end
+
+  def test_timestamp_column_values_are_present_in_the_callbacks
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = 'people'
+
+      before_create do
+        self.born_at = self.created_at
+      end
+    end
+
+    person = klass.create first_name: 'David'
+    assert_not_equal person.born_at, nil
+  end
+
+  def test_timestamp_attributes_for_create
+    toy = Toy.first
+    assert_equal [:created_at, :created_on], toy.send(:timestamp_attributes_for_create)
+  end
+
+  def test_timestamp_attributes_for_update
+    toy = Toy.first
+    assert_equal [:updated_at, :updated_on], toy.send(:timestamp_attributes_for_update)
+  end
+
+  def test_all_timestamp_attributes
+    toy = Toy.first
+    assert_equal [:created_at, :created_on, :updated_at, :updated_on], toy.send(:all_timestamp_attributes)
+  end
+
+  def test_timestamp_attributes_for_create_in_model
+    toy = Toy.first
+    assert_equal [:created_at], toy.send(:timestamp_attributes_for_create_in_model)
+  end
+
+  def test_timestamp_attributes_for_update_in_model
+    toy = Toy.first
+    assert_equal [:updated_at], toy.send(:timestamp_attributes_for_update_in_model)
+  end
+
+  def test_all_timestamp_attributes_in_model
+    toy = Toy.first
+    assert_equal [:created_at, :updated_at], toy.send(:all_timestamp_attributes_in_model)
+  end
+end
diff --git a/activerecord/test/cases/transaction_callbacks_test.rb b/activerecord/test/cases/transaction_callbacks_test.rb
new file mode 100644
index 0000000000..3d64ecb464
--- /dev/null
+++ b/activerecord/test/cases/transaction_callbacks_test.rb
@@ -0,0 +1,351 @@
+require "cases/helper"
+require 'models/owner'
+require 'models/pet'
+require 'models/topic'
+
+class TransactionCallbacksTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+  fixtures :topics, :owners, :pets
+
+  class ReplyWithCallbacks < ActiveRecord::Base
+    self.table_name = :topics
+
+    belongs_to :topic, foreign_key: "parent_id"
+
+    validates_presence_of :content
+
+    after_commit :do_after_commit, on: :create
+
+    attr_accessor :save_on_after_create
+    after_create do
+      self.save! if save_on_after_create
+    end
+
+    def history
+      @history ||= []
+    end
+
+    def do_after_commit
+      history << :commit_on_create
+    end
+  end
+
+  class TopicWithCallbacks < ActiveRecord::Base
+    self.table_name = :topics
+
+    has_many :replies, class_name: "ReplyWithCallbacks", foreign_key: "parent_id"
+
+    after_commit { |record| record.do_after_commit(nil) }
+    after_commit(on: :create) { |record| record.do_after_commit(:create) }
+    after_commit(on: :update) { |record| record.do_after_commit(:update) }
+    after_commit(on: :destroy) { |record| record.do_after_commit(:destroy) }
+    after_rollback { |record| record.do_after_rollback(nil) }
+    after_rollback(on: :create) { |record| record.do_after_rollback(:create) }
+    after_rollback(on: :update) { |record| record.do_after_rollback(:update) }
+    after_rollback(on: :destroy) { |record| record.do_after_rollback(:destroy) }
+
+    def history
+      @history ||= []
+    end
+
+    def after_commit_block(on = nil, &block)
+      @after_commit ||= {}
+      @after_commit[on] ||= []
+      @after_commit[on] << block
+    end
+
+    def after_rollback_block(on = nil, &block)
+      @after_rollback ||= {}
+      @after_rollback[on] ||= []
+      @after_rollback[on] << block
+    end
+
+    def do_after_commit(on)
+      blocks = @after_commit[on] if defined?(@after_commit)
+      blocks.each{|b| b.call(self)} if blocks
+    end
+
+    def do_after_rollback(on)
+      blocks = @after_rollback[on] if defined?(@after_rollback)
+      blocks.each{|b| b.call(self)} if blocks
+    end
+  end
+
+  def setup
+    @first = TopicWithCallbacks.find(1)
+  end
+
+  def test_call_after_commit_after_transaction_commits
+    @first.after_commit_block{|r| r.history << :after_commit}
+    @first.after_rollback_block{|r| r.history << :after_rollback}
+
+    @first.save!
+    assert_equal [:after_commit], @first.history
+  end
+
+  def test_only_call_after_commit_on_update_after_transaction_commits_for_existing_record
+    add_transaction_execution_blocks @first
+
+    @first.save!
+    assert_equal [:commit_on_update], @first.history
+  end
+
+  def test_only_call_after_commit_on_destroy_after_transaction_commits_for_destroyed_record
+    add_transaction_execution_blocks @first
+
+    @first.destroy
+    assert_equal [:commit_on_destroy], @first.history
+  end
+
+  def test_only_call_after_commit_on_create_after_transaction_commits_for_new_record
+    new_record = TopicWithCallbacks.new(:title => "New topic", :written_on => Date.today)
+    add_transaction_execution_blocks new_record
+
+    new_record.save!
+    assert_equal [:commit_on_create], new_record.history
+  end
+
+  def test_only_call_after_commit_on_create_after_transaction_commits_for_new_record_if_create_succeeds_creating_through_association
+    topic = TopicWithCallbacks.create!(:title => "New topic", :written_on => Date.today)
+    reply = topic.replies.create
+
+    assert_equal [], reply.history
+  end
+
+  def test_only_call_after_commit_on_create_and_doesnt_leaky
+    r = ReplyWithCallbacks.new(content: 'foo')
+    r.save_on_after_create = true
+    r.save!
+    r.content = 'bar'
+    r.save!
+    r.save!
+    assert_equal [:commit_on_create], r.history
+  end
+
+  def test_only_call_after_commit_on_update_after_transaction_commits_for_existing_record_on_touch
+    add_transaction_execution_blocks @first
+
+    @first.touch
+    assert_equal [:commit_on_update], @first.history
+  end
+
+  def test_call_after_rollback_after_transaction_rollsback
+    @first.after_commit_block{|r| r.history << :after_commit}
+    @first.after_rollback_block{|r| r.history << :after_rollback}
+
+    Topic.transaction do
+      @first.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:after_rollback], @first.history
+  end
+
+  def test_only_call_after_rollback_on_update_after_transaction_rollsback_for_existing_record
+    add_transaction_execution_blocks @first
+
+    Topic.transaction do
+      @first.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:rollback_on_update], @first.history
+  end
+
+  def test_only_call_after_rollback_on_update_after_transaction_rollsback_for_existing_record_on_touch
+    add_transaction_execution_blocks @first
+
+    Topic.transaction do
+      @first.touch
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:rollback_on_update], @first.history
+  end
+
+  def test_only_call_after_rollback_on_destroy_after_transaction_rollsback_for_destroyed_record
+    add_transaction_execution_blocks @first
+
+    Topic.transaction do
+      @first.destroy
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:rollback_on_destroy], @first.history
+  end
+
+  def test_only_call_after_rollback_on_create_after_transaction_rollsback_for_new_record
+    new_record = TopicWithCallbacks.new(:title => "New topic", :written_on => Date.today)
+    add_transaction_execution_blocks new_record
+
+    Topic.transaction do
+      new_record.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_equal [:rollback_on_create], new_record.history
+  end
+
+  def test_call_after_rollback_when_commit_fails
+    @first.class.connection.singleton_class.send(:alias_method, :real_method_commit_db_transaction, :commit_db_transaction)
+    begin
+      @first.class.connection.singleton_class.class_eval do
+        def commit_db_transaction; raise "boom!"; end
+      end
+
+      @first.after_commit_block{|r| r.history << :after_commit}
+      @first.after_rollback_block{|r| r.history << :after_rollback}
+
+      assert !@first.save rescue nil
+      assert_equal [:after_rollback], @first.history
+    ensure
+      @first.class.connection.singleton_class.send(:remove_method, :commit_db_transaction)
+      @first.class.connection.singleton_class.send(:alias_method, :commit_db_transaction, :real_method_commit_db_transaction)
+    end
+  end
+
+  def test_only_call_after_rollback_on_records_rolled_back_to_a_savepoint
+    def @first.rollbacks(i=0); @rollbacks ||= 0; @rollbacks += i if i; end
+    def @first.commits(i=0); @commits ||= 0; @commits += i if i; end
+    @first.after_rollback_block{|r| r.rollbacks(1)}
+    @first.after_commit_block{|r| r.commits(1)}
+
+    second = TopicWithCallbacks.find(3)
+    def second.rollbacks(i=0); @rollbacks ||= 0; @rollbacks += i if i; end
+    def second.commits(i=0); @commits ||= 0; @commits += i if i; end
+    second.after_rollback_block{|r| r.rollbacks(1)}
+    second.after_commit_block{|r| r.commits(1)}
+
+    Topic.transaction do
+      @first.save!
+      Topic.transaction(:requires_new => true) do
+        second.save!
+        raise ActiveRecord::Rollback
+      end
+    end
+
+    assert_equal 1, @first.commits
+    assert_equal 0, @first.rollbacks
+    assert_equal 0, second.commits
+    assert_equal 1, second.rollbacks
+  end
+
+  def test_only_call_after_rollback_on_records_rolled_back_to_a_savepoint_when_release_savepoint_fails
+    def @first.rollbacks(i=0); @rollbacks ||= 0; @rollbacks += i if i; end
+    def @first.commits(i=0); @commits ||= 0; @commits += i if i; end
+
+    @first.after_rollback_block{|r| r.rollbacks(1)}
+    @first.after_commit_block{|r| r.commits(1)}
+
+    Topic.transaction do
+      @first.save
+      Topic.transaction(:requires_new => true) do
+        @first.save!
+        raise ActiveRecord::Rollback
+      end
+      Topic.transaction(:requires_new => true) do
+        @first.save!
+        raise ActiveRecord::Rollback
+      end
+    end
+
+    assert_equal 1, @first.commits
+    assert_equal 2, @first.rollbacks
+  end
+
+  def test_after_transaction_callbacks_should_prevent_callbacks_from_being_called
+    def @first.last_after_transaction_error=(e); @last_transaction_error = e; end
+    def @first.last_after_transaction_error; @last_transaction_error; end
+    @first.after_commit_block{|r| r.last_after_transaction_error = :commit; raise "fail!";}
+    @first.after_rollback_block{|r| r.last_after_transaction_error = :rollback; raise "fail!";}
+
+    second = TopicWithCallbacks.find(3)
+    second.after_commit_block{|r| r.history << :after_commit}
+    second.after_rollback_block{|r| r.history << :after_rollback}
+
+    Topic.transaction do
+      @first.save!
+      second.save!
+    end
+    assert_equal :commit, @first.last_after_transaction_error
+    assert_equal [:after_commit], second.history
+
+    second.history.clear
+    Topic.transaction do
+      @first.save!
+      second.save!
+      raise ActiveRecord::Rollback
+    end
+    assert_equal :rollback, @first.last_after_transaction_error
+    assert_equal [:after_rollback], second.history
+  end
+
+  def test_after_rollback_callbacks_should_validate_on_condition
+    assert_raise(ArgumentError) { Topic.after_rollback(on: :save) }
+  end
+
+  def test_after_commit_callbacks_should_validate_on_condition
+    assert_raise(ArgumentError) { Topic.after_commit(on: :save) }
+  end
+
+  def test_saving_a_record_with_a_belongs_to_that_specifies_touching_the_parent_should_call_callbacks_on_the_parent_object
+    pet   = Pet.first
+    owner = pet.owner
+    flag = false
+
+    owner.on_after_commit do
+      flag = true
+    end
+
+    pet.name = "Fluffy the Third"
+    pet.save
+
+    assert flag
+  end
+
+  private
+
+    def add_transaction_execution_blocks(record)
+      record.after_commit_block(:create) { |r| r.history << :commit_on_create }
+      record.after_commit_block(:update) { |r| r.history << :commit_on_update }
+      record.after_commit_block(:destroy) { |r| r.history << :commit_on_destroy }
+      record.after_rollback_block(:create) { |r| r.history << :rollback_on_create }
+      record.after_rollback_block(:update) { |r| r.history << :rollback_on_update }
+      record.after_rollback_block(:destroy) { |r| r.history << :rollback_on_destroy }
+    end
+end
+
+class CallbacksOnMultipleActionsTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  class TopicWithCallbacksOnMultipleActions < ActiveRecord::Base
+    self.table_name = :topics
+
+    after_commit(on: [:create, :destroy]) { |record| record.history << :create_and_destroy }
+    after_commit(on: [:create, :update]) { |record| record.history << :create_and_update }
+    after_commit(on: [:update, :destroy]) { |record| record.history << :update_and_destroy }
+
+    def clear_history
+      @history = []
+    end
+
+    def history
+      @history ||= []
+    end
+  end
+
+  def test_after_commit_on_multiple_actions
+    topic = TopicWithCallbacksOnMultipleActions.new
+    topic.save
+    assert_equal [:create_and_update, :create_and_destroy], topic.history
+
+    topic.clear_history
+    topic.approved = true
+    topic.save
+    assert_equal [:update_and_destroy, :create_and_update], topic.history
+
+    topic.clear_history
+    topic.destroy
+    assert_equal [:update_and_destroy, :create_and_destroy], topic.history
+  end
+end
diff --git a/activerecord/test/cases/transaction_isolation_test.rb b/activerecord/test/cases/transaction_isolation_test.rb
new file mode 100644
index 0000000000..f89c26532d
--- /dev/null
+++ b/activerecord/test/cases/transaction_isolation_test.rb
@@ -0,0 +1,106 @@
+require 'cases/helper'
+
+unless ActiveRecord::Base.connection.supports_transaction_isolation?
+  class TransactionIsolationUnsupportedTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    class Tag < ActiveRecord::Base
+    end
+
+    test "setting the isolation level raises an error" do
+      assert_raises(ActiveRecord::TransactionIsolationError) do
+        Tag.transaction(isolation: :serializable) { }
+      end
+    end
+  end
+end
+
+if ActiveRecord::Base.connection.supports_transaction_isolation?
+  class TransactionIsolationTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    class Tag < ActiveRecord::Base
+      self.table_name = 'tags'
+    end
+
+    class Tag2 < ActiveRecord::Base
+      self.table_name = 'tags'
+    end
+
+    setup do
+      Tag.establish_connection :arunit
+      Tag2.establish_connection :arunit
+      Tag.destroy_all
+    end
+
+    # It is impossible to properly test read uncommitted. The SQL standard only
+    # specifies what must not happen at a certain level, not what must happen. At
+    # the read uncommitted level, there is nothing that must not happen.
+    if ActiveRecord::Base.connection.transaction_isolation_levels.include?(:read_uncommitted)
+      test "read uncommitted" do
+        Tag.transaction(isolation: :read_uncommitted) do
+          assert_equal 0, Tag.count
+          Tag2.create
+          assert_equal 1, Tag.count
+        end
+      end
+    end
+
+    # We are testing that a dirty read does not happen
+    test "read committed" do
+      Tag.transaction(isolation: :read_committed) do
+        assert_equal 0, Tag.count
+
+        Tag2.transaction do
+          Tag2.create
+          assert_equal 0, Tag.count
+        end
+      end
+
+      assert_equal 1, Tag.count
+    end
+
+    # We are testing that a nonrepeatable read does not happen
+    if ActiveRecord::Base.connection.transaction_isolation_levels.include?(:repeatable_read)
+      test "repeatable read" do
+        tag = Tag.create(name: 'jon')
+
+        Tag.transaction(isolation: :repeatable_read) do
+          tag.reload
+          Tag2.find(tag.id).update(name: 'emily')
+
+          tag.reload
+          assert_equal 'jon', tag.name
+        end
+
+        tag.reload
+        assert_equal 'emily', tag.name
+      end
+    end
+
+    # We are only testing that there are no errors because it's too hard to
+    # test serializable. Databases behave differently to enforce the serializability
+    # constraint.
+    test "serializable" do
+      Tag.transaction(isolation: :serializable) do
+        Tag.create
+      end
+    end
+
+    test "setting isolation when joining a transaction raises an error" do
+      Tag.transaction do
+        assert_raises(ActiveRecord::TransactionIsolationError) do
+          Tag.transaction(isolation: :serializable) { }
+        end
+      end
+    end
+
+    test "setting isolation when starting a nested transaction raises error" do
+      Tag.transaction do
+        assert_raises(ActiveRecord::TransactionIsolationError) do
+          Tag.transaction(requires_new: true, isolation: :serializable) { }
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
new file mode 100644
index 0000000000..b4849222b8
--- /dev/null
+++ b/activerecord/test/cases/transactions_test.rb
@@ -0,0 +1,700 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/reply'
+require 'models/developer'
+require 'models/book'
+require 'models/author'
+require 'models/post'
+require 'models/movie'
+
+class TransactionTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+  fixtures :topics, :developers, :authors, :posts
+
+  def setup
+    @first, @second = Topic.find(1, 2).sort_by { |t| t.id }
+  end
+
+  def test_persisted_in_a_model_with_custom_primary_key_after_failed_save
+    movie = Movie.create
+    assert !movie.persisted?
+  end
+
+  def test_raise_after_destroy
+    assert_not @first.frozen?
+
+    assert_raises(RuntimeError) {
+      Topic.transaction do
+        @first.destroy
+        assert @first.frozen?
+        raise
+      end
+    }
+
+    assert @first.reload
+    assert_not @first.frozen?
+  end
+
+  def test_successful
+    Topic.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save
+      @second.save
+    end
+
+    assert Topic.find(1).approved?, "First should have been approved"
+    assert !Topic.find(2).approved?, "Second should have been unapproved"
+  end
+
+  def transaction_with_return
+    Topic.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save
+      @second.save
+      return
+    end
+  end
+
+  def test_successful_with_return
+    committed = false
+
+    Topic.connection.class_eval do
+      alias :real_commit_db_transaction :commit_db_transaction
+      define_method(:commit_db_transaction) do
+        committed = true
+        real_commit_db_transaction
+      end
+    end
+
+    transaction_with_return
+    assert committed
+
+    assert Topic.find(1).approved?, "First should have been approved"
+    assert !Topic.find(2).approved?, "Second should have been unapproved"
+  ensure
+    Topic.connection.class_eval do
+      remove_method :commit_db_transaction
+      alias :commit_db_transaction :real_commit_db_transaction rescue nil
+    end
+  end
+
+  def test_successful_with_instance_method
+    @first.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save
+      @second.save
+    end
+
+    assert Topic.find(1).approved?, "First should have been approved"
+    assert !Topic.find(2).approved?, "Second should have been unapproved"
+  end
+
+  def test_failing_on_exception
+    begin
+      Topic.transaction do
+        @first.approved  = true
+        @second.approved = false
+        @first.save
+        @second.save
+        raise "Bad things!"
+      end
+    rescue
+      # caught it
+    end
+
+    assert @first.approved?, "First should still be changed in the objects"
+    assert !@second.approved?, "Second should still be changed in the objects"
+
+    assert !Topic.find(1).approved?, "First shouldn't have been approved"
+    assert Topic.find(2).approved?, "Second should still be approved"
+  end
+
+  def test_raising_exception_in_callback_rollbacks_in_save
+    def @first.after_save_for_transaction
+      raise 'Make the transaction rollback'
+    end
+
+    @first.approved = true
+    e = assert_raises(RuntimeError) { @first.save }
+    assert_equal "Make the transaction rollback", e.message
+    assert !Topic.find(1).approved?
+  end
+
+  def test_rolling_back_in_a_callback_rollbacks_before_save
+    def @first.before_save_for_transaction
+      raise ActiveRecord::Rollback
+    end
+    assert !@first.approved
+
+    Topic.transaction do
+      @first.approved  = true
+      @first.save!
+    end
+    assert !Topic.find(@first.id).approved?, "Should not commit the approved flag"
+  end
+
+  def test_raising_exception_in_nested_transaction_restore_state_in_save
+    topic = Topic.new
+
+    def topic.after_save_for_transaction
+      raise 'Make the transaction rollback'
+    end
+
+    assert_raises(RuntimeError) do
+      Topic.transaction { topic.save }
+    end
+
+    assert topic.new_record?, "#{topic.inspect} should be new record"
+  end
+
+  def test_update_should_rollback_on_failure
+    author = Author.find(1)
+    posts_count = author.posts.size
+    assert posts_count > 0
+    status = author.update(name: nil, post_ids: [])
+    assert !status
+    assert_equal posts_count, author.posts(true).size
+  end
+
+  def test_update_should_rollback_on_failure!
+    author = Author.find(1)
+    posts_count = author.posts.size
+    assert posts_count > 0
+    assert_raise(ActiveRecord::RecordInvalid) do
+      author.update!(name: nil, post_ids: [])
+    end
+    assert_equal posts_count, author.posts(true).size
+  end
+
+  def test_cancellation_from_before_destroy_rollbacks_in_destroy
+    add_cancelling_before_destroy_with_db_side_effect_to_topic @first
+    nbooks_before_destroy = Book.count
+    status = @first.destroy
+    assert !status
+    @first.reload
+    assert_equal nbooks_before_destroy, Book.count
+  end
+
+  %w(validation save).each do |filter|
+    define_method("test_cancellation_from_before_filters_rollbacks_in_#{filter}") do
+      send("add_cancelling_before_#{filter}_with_db_side_effect_to_topic", @first)
+      nbooks_before_save = Book.count
+      original_author_name = @first.author_name
+      @first.author_name += '_this_should_not_end_up_in_the_db'
+      status = @first.save
+      assert !status
+      assert_equal original_author_name, @first.reload.author_name
+      assert_equal nbooks_before_save, Book.count
+    end
+
+    define_method("test_cancellation_from_before_filters_rollbacks_in_#{filter}!") do
+      send("add_cancelling_before_#{filter}_with_db_side_effect_to_topic", @first)
+      nbooks_before_save = Book.count
+      original_author_name = @first.author_name
+      @first.author_name += '_this_should_not_end_up_in_the_db'
+
+      begin
+        @first.save!
+      rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotSaved
+      end
+
+      assert_equal original_author_name, @first.reload.author_name
+      assert_equal nbooks_before_save, Book.count
+    end
+  end
+
+  def test_callback_rollback_in_create
+    topic = Class.new(Topic) {
+      def after_create_for_transaction
+        raise 'Make the transaction rollback'
+      end
+    }
+
+    new_topic = topic.new(:title                => "A new topic",
+                          :author_name          => "Ben",
+                          :author_email_address => "ben@example.com",
+                          :written_on           => "2003-07-16t15:28:11.2233+01:00",
+                          :last_read            => "2004-04-15",
+                          :bonus_time           => "2005-01-30t15:28:00.00+01:00",
+                          :content              => "Have a nice day",
+                          :approved             => false)
+
+    new_record_snapshot = !new_topic.persisted?
+    id_present = new_topic.has_attribute?(Topic.primary_key)
+    id_snapshot = new_topic.id
+
+    # Make sure the second save gets the after_create callback called.
+    2.times do
+      new_topic.approved = true
+      e = assert_raises(RuntimeError) { new_topic.save }
+      assert_equal "Make the transaction rollback", e.message
+      assert_equal new_record_snapshot, !new_topic.persisted?, "The topic should have its old persisted value"
+      assert_equal id_snapshot, new_topic.id, "The topic should have its old id"
+      assert_equal id_present, new_topic.has_attribute?(Topic.primary_key)
+    end
+  end
+
+  def test_callback_rollback_in_create_with_record_invalid_exception
+    topic = Class.new(Topic) {
+      def after_create_for_transaction
+        raise ActiveRecord::RecordInvalid.new(Author.new)
+      end
+    }
+
+    new_topic = topic.create(:title => "A new topic")
+    assert !new_topic.persisted?, "The topic should not be persisted"
+    assert_nil new_topic.id, "The topic should not have an ID"
+  end
+
+  def test_nested_explicit_transactions
+    Topic.transaction do
+      Topic.transaction do
+        @first.approved  = true
+        @second.approved = false
+        @first.save
+        @second.save
+      end
+    end
+
+    assert Topic.find(1).approved?, "First should have been approved"
+    assert !Topic.find(2).approved?, "Second should have been unapproved"
+  end
+
+  def test_manually_rolling_back_a_transaction
+    Topic.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save
+      @second.save
+
+      raise ActiveRecord::Rollback
+    end
+
+    assert @first.approved?, "First should still be changed in the objects"
+    assert !@second.approved?, "Second should still be changed in the objects"
+
+    assert !Topic.find(1).approved?, "First shouldn't have been approved"
+    assert Topic.find(2).approved?, "Second should still be approved"
+  end
+
+  def test_invalid_keys_for_transaction
+    assert_raise ArgumentError do
+      Topic.transaction :nested => true do
+      end
+    end
+  end
+
+  def test_force_savepoint_in_nested_transaction
+    Topic.transaction do
+      @first.approved = true
+      @second.approved = false
+      @first.save!
+      @second.save!
+
+      begin
+        Topic.transaction :requires_new => true do
+          @first.happy = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert @first.reload.approved?
+    assert !@second.reload.approved?
+  end if Topic.connection.supports_savepoints?
+
+  def test_force_savepoint_on_instance
+    @first.transaction do
+      @first.approved  = true
+      @second.approved = false
+      @first.save!
+      @second.save!
+
+      begin
+        @second.transaction :requires_new => true do
+          @first.happy = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert @first.reload.approved?
+    assert !@second.reload.approved?
+  end if Topic.connection.supports_savepoints?
+
+  def test_no_savepoint_in_nested_transaction_without_force
+    Topic.transaction do
+      @first.approved = true
+      @second.approved = false
+      @first.save!
+      @second.save!
+
+      begin
+        Topic.transaction do
+          @first.approved = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert !@first.reload.approved?
+    assert !@second.reload.approved?
+  end if Topic.connection.supports_savepoints?
+
+  def test_many_savepoints
+    Topic.transaction do
+      @first.content = "One"
+      @first.save!
+
+      begin
+        Topic.transaction :requires_new => true do
+          @first.content = "Two"
+          @first.save!
+
+          begin
+            Topic.transaction :requires_new => true do
+              @first.content = "Three"
+              @first.save!
+
+              begin
+                Topic.transaction :requires_new => true do
+                  @first.content = "Four"
+                  @first.save!
+                  raise
+                end
+              rescue
+              end
+
+              @three = @first.reload.content
+              raise
+            end
+          rescue
+          end
+
+          @two = @first.reload.content
+          raise
+        end
+      rescue
+      end
+
+      @one = @first.reload.content
+    end
+
+    assert_equal "One", @one
+    assert_equal "Two", @two
+    assert_equal "Three", @three
+  end if Topic.connection.supports_savepoints?
+
+  def test_using_named_savepoints
+    Topic.transaction do
+      @first.approved  = true
+      @first.save!
+      Topic.connection.create_savepoint("first")
+
+      @first.approved  = false
+      @first.save!
+      Topic.connection.rollback_to_savepoint("first")
+      assert @first.reload.approved?
+
+      @first.approved  = false
+      @first.save!
+      Topic.connection.release_savepoint("first")
+      assert_not @first.reload.approved?
+    end
+  end if Topic.connection.supports_savepoints?
+
+  def test_releasing_named_savepoints
+    Topic.transaction do
+      Topic.connection.create_savepoint("another")
+      Topic.connection.release_savepoint("another")
+
+      # The savepoint is now gone and we can't remove it again.
+      assert_raises(ActiveRecord::StatementInvalid) do
+        Topic.connection.release_savepoint("another")
+      end
+    end
+  end
+
+  def test_savepoints_name
+    Topic.transaction do
+      assert_nil Topic.connection.current_savepoint_name
+      assert_nil Topic.connection.current_transaction.savepoint_name
+
+      Topic.transaction(requires_new: true) do
+        assert_equal "active_record_1", Topic.connection.current_savepoint_name
+        assert_equal "active_record_1", Topic.connection.current_transaction.savepoint_name
+
+        Topic.transaction(requires_new: true) do
+          assert_equal "active_record_2", Topic.connection.current_savepoint_name
+          assert_equal "active_record_2", Topic.connection.current_transaction.savepoint_name
+        end
+
+        assert_equal "active_record_1", Topic.connection.current_savepoint_name
+        assert_equal "active_record_1", Topic.connection.current_transaction.savepoint_name
+      end
+    end
+  end
+
+  def test_rollback_when_commit_raises
+    Topic.connection.expects(:begin_db_transaction)
+    Topic.connection.expects(:commit_db_transaction).raises('OH NOES')
+    Topic.connection.expects(:rollback_db_transaction)
+
+    assert_raise RuntimeError do
+      Topic.transaction do
+        # do nothing
+      end
+    end
+  end
+
+  def test_rollback_when_saving_a_frozen_record
+    topic = Topic.new(:title => 'test')
+    topic.freeze
+    e = assert_raise(RuntimeError) { topic.save }
+    assert_match(/frozen/i, e.message) # Not good enough, but we can't do much
+                                       # about it since there is no specific error
+                                       # for frozen objects.
+    assert !topic.persisted?, 'not persisted'
+    assert_nil topic.id
+    assert topic.frozen?, 'not frozen'
+  end
+
+  def test_restore_active_record_state_for_all_records_in_a_transaction
+    topic_without_callbacks = Class.new(ActiveRecord::Base) do
+      self.table_name = 'topics'
+    end
+
+    topic_1 = Topic.new(:title => 'test_1')
+    topic_2 = Topic.new(:title => 'test_2')
+    topic_3 = topic_without_callbacks.new(:title => 'test_3')
+
+    Topic.transaction do
+      assert topic_1.save
+      assert topic_2.save
+      assert topic_3.save
+      @first.save
+      @second.destroy
+      assert topic_1.persisted?, 'persisted'
+      assert_not_nil topic_1.id
+      assert topic_2.persisted?, 'persisted'
+      assert_not_nil topic_2.id
+      assert topic_3.persisted?, 'persisted'
+      assert_not_nil topic_3.id
+      assert @first.persisted?, 'persisted'
+      assert_not_nil @first.id
+      assert @second.destroyed?, 'destroyed'
+      raise ActiveRecord::Rollback
+    end
+
+    assert !topic_1.persisted?, 'not persisted'
+    assert_nil topic_1.id
+    assert !topic_2.persisted?, 'not persisted'
+    assert_nil topic_2.id
+    assert !topic_3.persisted?, 'not persisted'
+    assert_nil topic_3.id
+    assert @first.persisted?, 'persisted'
+    assert_not_nil @first.id
+    assert !@second.destroyed?, 'not destroyed'
+  end
+
+  def test_sqlite_add_column_in_transaction
+    return true unless current_adapter?(:SQLite3Adapter)
+
+    # Test first if column creation/deletion works correctly when no
+    # transaction is in place.
+    #
+    # We go back to the connection for the column queries because
+    # Topic.columns is cached and won't report changes to the DB
+
+    assert_nothing_raised do
+      Topic.reset_column_information
+      Topic.connection.add_column('topics', 'stuff', :string)
+      assert Topic.column_names.include?('stuff')
+
+      Topic.reset_column_information
+      Topic.connection.remove_column('topics', 'stuff')
+      assert !Topic.column_names.include?('stuff')
+    end
+
+    if Topic.connection.supports_ddl_transactions?
+      assert_nothing_raised do
+        Topic.transaction { Topic.connection.add_column('topics', 'stuff', :string) }
+      end
+    else
+      Topic.transaction do
+        assert_raise(ActiveRecord::StatementInvalid) { Topic.connection.add_column('topics', 'stuff', :string) }
+        raise ActiveRecord::Rollback
+      end
+    end
+  ensure
+    begin
+      Topic.connection.remove_column('topics', 'stuff')
+    rescue
+    ensure
+      Topic.reset_column_information
+    end
+  end
+
+  def test_transactions_state_from_rollback
+    connection = Topic.connection
+    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
+
+    assert transaction.open?
+    assert !transaction.state.rolledback?
+    assert !transaction.state.committed?
+
+    transaction.rollback
+
+    assert transaction.state.rolledback?
+    assert !transaction.state.committed?
+  end
+
+  def test_transactions_state_from_commit
+    connection = Topic.connection
+    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
+
+    assert transaction.open?
+    assert !transaction.state.rolledback?
+    assert !transaction.state.committed?
+
+    transaction.commit
+
+    assert !transaction.state.rolledback?
+    assert transaction.state.committed?
+  end
+
+  private
+
+  %w(validation save destroy).each do |filter|
+    define_method("add_cancelling_before_#{filter}_with_db_side_effect_to_topic") do |topic|
+      meta = class << topic; self; end
+      meta.send("define_method", "before_#{filter}_for_transaction") do
+        Book.create
+        false
+      end
+    end
+  end
+end
+
+class TransactionsWithTransactionalFixturesTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = true
+  fixtures :topics
+
+  def test_automatic_savepoint_in_outer_transaction
+    @first = Topic.find(1)
+
+    begin
+      Topic.transaction do
+        @first.approved = true
+        @first.save!
+        raise
+      end
+    rescue
+      assert !@first.reload.approved?
+    end
+  end
+
+  def test_no_automatic_savepoint_for_inner_transaction
+    @first = Topic.find(1)
+
+    Topic.transaction do
+      @first.approved = true
+      @first.save!
+
+      begin
+        Topic.transaction do
+          @first.approved = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert !@first.reload.approved?
+  end
+end if Topic.connection.supports_savepoints?
+
+if current_adapter?(:PostgreSQLAdapter)
+  class ConcurrentTransactionTest < TransactionTest
+    # This will cause transactions to overlap and fail unless they are performed on
+    # separate database connections.
+    unless in_memory_db?
+      def test_transaction_per_thread
+        threads = 3.times.map do
+          Thread.new do
+            Topic.transaction do
+              topic = Topic.find(1)
+              topic.approved = !topic.approved?
+              assert topic.save!
+              topic.approved = !topic.approved?
+              assert topic.save!
+            end
+            Topic.connection.close
+          end
+        end
+
+        threads.each { |t| t.join }
+      end
+    end
+
+    # Test for dirty reads among simultaneous transactions.
+    def test_transaction_isolation__read_committed
+      # Should be invariant.
+      original_salary = Developer.find(1).salary
+      temporary_salary = 200000
+
+      assert_nothing_raised do
+        threads = (1..3).map do
+          Thread.new do
+            Developer.transaction do
+              # Expect original salary.
+              dev = Developer.find(1)
+              assert_equal original_salary, dev.salary
+
+              dev.salary = temporary_salary
+              dev.save!
+
+              # Expect temporary salary.
+              dev = Developer.find(1)
+              assert_equal temporary_salary, dev.salary
+
+              dev.salary = original_salary
+              dev.save!
+
+              # Expect original salary.
+              dev = Developer.find(1)
+              assert_equal original_salary, dev.salary
+            end
+            Developer.connection.close
+          end
+        end
+
+        # Keep our eyes peeled.
+        threads << Thread.new do
+          10.times do
+            sleep 0.05
+            Developer.transaction do
+              # Always expect original salary.
+              assert_equal original_salary, Developer.find(1).salary
+            end
+          end
+          Developer.connection.close
+        end
+
+        threads.each { |t| t.join }
+      end
+
+      assert_equal original_salary, Developer.find(1).salary
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/decimal_test.rb b/activerecord/test/cases/type/decimal_test.rb
new file mode 100644
index 0000000000..da30de373e
--- /dev/null
+++ b/activerecord/test/cases/type/decimal_test.rb
@@ -0,0 +1,38 @@
+require "cases/helper"
+
+module ActiveRecord
+  module Type
+    class DecimalTest < ActiveRecord::TestCase
+      def test_type_cast_decimal
+        type = Decimal.new
+        assert_equal BigDecimal.new("0"), type.type_cast_from_user(BigDecimal.new("0"))
+        assert_equal BigDecimal.new("123"), type.type_cast_from_user(123.0)
+        assert_equal BigDecimal.new("1"), type.type_cast_from_user(:"1")
+      end
+
+      def test_type_cast_decimal_from_float_with_large_precision
+        type = Decimal.new(precision: ::Float::DIG + 2)
+        assert_equal BigDecimal.new("123.0"), type.type_cast_from_user(123.0)
+      end
+
+      def test_type_cast_decimal_from_rational_with_precision
+        type = Decimal.new(precision: 2)
+        assert_equal BigDecimal("0.33"), type.type_cast_from_user(Rational(1, 3))
+      end
+
+      def test_type_cast_decimal_from_rational_without_precision_defaults_to_18_36
+        type = Decimal.new
+        assert_equal BigDecimal("0.333333333333333333E0"), type.type_cast_from_user(Rational(1, 3))
+      end
+
+      def test_type_cast_decimal_from_object_responding_to_d
+        value = Object.new
+        def value.to_d
+          BigDecimal.new("1")
+        end
+        type = Decimal.new
+        assert_equal BigDecimal("1"), type.type_cast_from_user(value)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/string_test.rb b/activerecord/test/cases/type/string_test.rb
new file mode 100644
index 0000000000..420177ed49
--- /dev/null
+++ b/activerecord/test/cases/type/string_test.rb
@@ -0,0 +1,36 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class StringTypeTest < ActiveRecord::TestCase
+    test "type casting" do
+      type = Type::String.new
+      assert_equal "1", type.type_cast_from_user(true)
+      assert_equal "0", type.type_cast_from_user(false)
+      assert_equal "123", type.type_cast_from_user(123)
+    end
+
+    test "values are duped coming out" do
+      s = "foo"
+      type = Type::String.new
+      assert_not_same s, type.type_cast_from_user(s)
+      assert_not_same s, type.type_cast_from_database(s)
+    end
+
+    test "string mutations are detected" do
+      klass = Class.new(Base)
+      klass.table_name = 'authors'
+
+      author = klass.create!(name: 'Sean')
+      assert_not author.changed?
+
+      author.name << ' Griffin'
+      assert author.name_changed?
+
+      author.save!
+      author.reload
+
+      assert_equal 'Sean Griffin', author.name
+      assert_not author.changed?
+    end
+  end
+end
diff --git a/activerecord/test/cases/type/type_map_test.rb b/activerecord/test/cases/type/type_map_test.rb
new file mode 100644
index 0000000000..4e32f92dd0
--- /dev/null
+++ b/activerecord/test/cases/type/type_map_test.rb
@@ -0,0 +1,130 @@
+require "cases/helper"
+
+module ActiveRecord
+  module Type
+    class TypeMapTest < ActiveRecord::TestCase
+      def test_default_type
+        mapping = TypeMap.new
+
+        assert_kind_of Value, mapping.lookup(:undefined)
+      end
+
+      def test_registering_types
+        boolean = Boolean.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/boolean/i, boolean)
+
+        assert_equal mapping.lookup('boolean'), boolean
+      end
+
+      def test_overriding_registered_types
+        time = Time.new
+        timestamp = DateTime.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/time/i, time)
+        mapping.register_type(/time/i, timestamp)
+
+        assert_equal mapping.lookup('time'), timestamp
+      end
+
+      def test_fuzzy_lookup
+        string = String.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/varchar/i, string)
+
+        assert_equal mapping.lookup('varchar(20)'), string
+      end
+
+      def test_aliasing_types
+        string = String.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/string/i, string)
+        mapping.alias_type(/varchar/i, 'string')
+
+        assert_equal mapping.lookup('varchar'), string
+      end
+
+      def test_changing_type_changes_aliases
+        time = Time.new
+        timestamp = DateTime.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/timestamp/i, time)
+        mapping.alias_type(/datetime/i, 'timestamp')
+        mapping.register_type(/timestamp/i, timestamp)
+
+        assert_equal mapping.lookup('datetime'), timestamp
+      end
+
+      def test_aliases_keep_metadata
+        mapping = TypeMap.new
+
+        mapping.register_type(/decimal/i) { |sql_type| sql_type }
+        mapping.alias_type(/number/i, 'decimal')
+
+        assert_equal mapping.lookup('number(20)'), 'decimal(20)'
+        assert_equal mapping.lookup('number'), 'decimal'
+      end
+
+      def test_register_proc
+        string = String.new
+        binary = Binary.new
+        mapping = TypeMap.new
+
+        mapping.register_type(/varchar/i) do |type|
+          if type.include?('(')
+            string
+          else
+            binary
+          end
+        end
+
+        assert_equal mapping.lookup('varchar(20)'), string
+        assert_equal mapping.lookup('varchar'), binary
+      end
+
+      def test_additional_lookup_args
+        mapping = TypeMap.new
+
+        mapping.register_type(/varchar/i) do |type, limit|
+          if limit > 255
+            'text'
+          else
+            'string'
+          end
+        end
+        mapping.alias_type(/string/i, 'varchar')
+
+        assert_equal mapping.lookup('varchar', 200), 'string'
+        assert_equal mapping.lookup('varchar', 400), 'text'
+        assert_equal mapping.lookup('string', 400), 'text'
+      end
+
+      def test_requires_value_or_block
+        mapping = TypeMap.new
+
+        assert_raises(ArgumentError) do
+          mapping.register_type(/only key/i)
+        end
+      end
+
+      def test_lookup_non_strings
+        mapping = HashLookupTypeMap.new
+
+        mapping.register_type(1, 'string')
+        mapping.register_type(2, 'int')
+        mapping.alias_type(3, 1)
+
+        assert_equal mapping.lookup(1), 'string'
+        assert_equal mapping.lookup(2), 'int'
+        assert_equal mapping.lookup(3), 'string'
+        assert_kind_of Type::Value, mapping.lookup(4)
+      end
+    end
+  end
+end
+
diff --git a/activerecord/test/cases/types_test.rb b/activerecord/test/cases/types_test.rb
new file mode 100644
index 0000000000..5c54812f30
--- /dev/null
+++ b/activerecord/test/cases/types_test.rb
@@ -0,0 +1,163 @@
+require "cases/helper"
+require 'models/company'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class TypesTest < ActiveRecord::TestCase
+      def test_type_cast_boolean
+        type = Type::Boolean.new
+        assert type.type_cast_from_user('').nil?
+        assert type.type_cast_from_user(nil).nil?
+
+        assert type.type_cast_from_user(true)
+        assert type.type_cast_from_user(1)
+        assert type.type_cast_from_user('1')
+        assert type.type_cast_from_user('t')
+        assert type.type_cast_from_user('T')
+        assert type.type_cast_from_user('true')
+        assert type.type_cast_from_user('TRUE')
+        assert type.type_cast_from_user('on')
+        assert type.type_cast_from_user('ON')
+
+        # explicitly check for false vs nil
+        assert_equal false, type.type_cast_from_user(false)
+        assert_equal false, type.type_cast_from_user(0)
+        assert_equal false, type.type_cast_from_user('0')
+        assert_equal false, type.type_cast_from_user('f')
+        assert_equal false, type.type_cast_from_user('F')
+        assert_equal false, type.type_cast_from_user('false')
+        assert_equal false, type.type_cast_from_user('FALSE')
+        assert_equal false, type.type_cast_from_user('off')
+        assert_equal false, type.type_cast_from_user('OFF')
+        assert_equal false, type.type_cast_from_user(' ')
+        assert_equal false, type.type_cast_from_user("\u3000\r\n")
+        assert_equal false, type.type_cast_from_user("\u0000")
+        assert_equal false, type.type_cast_from_user('SOMETHING RANDOM')
+      end
+
+      def test_type_cast_integer
+        type = Type::Integer.new
+        assert_equal 1, type.type_cast_from_user(1)
+        assert_equal 1, type.type_cast_from_user('1')
+        assert_equal 1, type.type_cast_from_user('1ignore')
+        assert_equal 0, type.type_cast_from_user('bad1')
+        assert_equal 0, type.type_cast_from_user('bad')
+        assert_equal 1, type.type_cast_from_user(1.7)
+        assert_equal 0, type.type_cast_from_user(false)
+        assert_equal 1, type.type_cast_from_user(true)
+        assert_nil type.type_cast_from_user(nil)
+      end
+
+      def test_type_cast_non_integer_to_integer
+        type = Type::Integer.new
+        assert_nil type.type_cast_from_user([1,2])
+        assert_nil type.type_cast_from_user({1 => 2})
+        assert_nil type.type_cast_from_user((1..2))
+      end
+
+      def test_type_cast_activerecord_to_integer
+        type = Type::Integer.new
+        firm = Firm.create(:name => 'Apple')
+        assert_nil type.type_cast_from_user(firm)
+      end
+
+      def test_type_cast_object_without_to_i_to_integer
+        type = Type::Integer.new
+        assert_nil type.type_cast_from_user(Object.new)
+      end
+
+      def test_type_cast_nan_and_infinity_to_integer
+        type = Type::Integer.new
+        assert_nil type.type_cast_from_user(Float::NAN)
+        assert_nil type.type_cast_from_user(1.0/0.0)
+      end
+
+      def test_changing_integers
+        type = Type::Integer.new
+
+        assert type.changed?(5, 5, '5wibble')
+        assert_not type.changed?(5, 5, '5')
+        assert_not type.changed?(5, 5, '5.0')
+        assert_not type.changed?(nil, nil, nil)
+      end
+
+      def test_type_cast_float
+        type = Type::Float.new
+        assert_equal 1.0, type.type_cast_from_user("1")
+      end
+
+      def test_changing_float
+        type = Type::Float.new
+
+        assert type.changed?(5.0, 5.0, '5wibble')
+        assert_not type.changed?(5.0, 5.0, '5')
+        assert_not type.changed?(5.0, 5.0, '5.0')
+        assert_not type.changed?(nil, nil, nil)
+      end
+
+      def test_type_cast_binary
+        type = Type::Binary.new
+        assert_equal nil, type.type_cast_from_user(nil)
+        assert_equal "1", type.type_cast_from_user("1")
+        assert_equal 1, type.type_cast_from_user(1)
+      end
+
+      def test_type_cast_time
+        type = Type::Time.new
+        assert_equal nil, type.type_cast_from_user(nil)
+        assert_equal nil, type.type_cast_from_user('')
+        assert_equal nil, type.type_cast_from_user('ABC')
+
+        time_string = Time.now.utc.strftime("%T")
+        assert_equal time_string, type.type_cast_from_user(time_string).strftime("%T")
+      end
+
+      def test_type_cast_datetime_and_timestamp
+        type = Type::DateTime.new
+        assert_equal nil, type.type_cast_from_user(nil)
+        assert_equal nil, type.type_cast_from_user('')
+        assert_equal nil, type.type_cast_from_user('  ')
+        assert_equal nil, type.type_cast_from_user('ABC')
+
+        datetime_string = Time.now.utc.strftime("%FT%T")
+        assert_equal datetime_string, type.type_cast_from_user(datetime_string).strftime("%FT%T")
+      end
+
+      def test_type_cast_date
+        type = Type::Date.new
+        assert_equal nil, type.type_cast_from_user(nil)
+        assert_equal nil, type.type_cast_from_user('')
+        assert_equal nil, type.type_cast_from_user(' ')
+        assert_equal nil, type.type_cast_from_user('ABC')
+
+        date_string = Time.now.utc.strftime("%F")
+        assert_equal date_string, type.type_cast_from_user(date_string).strftime("%F")
+      end
+
+      def test_type_cast_duration_to_integer
+        type = Type::Integer.new
+        assert_equal 1800, type.type_cast_from_user(30.minutes)
+        assert_equal 7200, type.type_cast_from_user(2.hours)
+      end
+
+      def test_string_to_time_with_timezone
+        [:utc, :local].each do |zone|
+          with_timezone_config default: zone do
+            type = Type::DateTime.new
+            assert_equal Time.utc(2013, 9, 4, 0, 0, 0), type.type_cast_from_user("Wed, 04 Sep 2013 03:00:00 EAT")
+          end
+        end
+      end
+
+      if current_adapter?(:SQLite3Adapter)
+        def test_binary_encoding
+          type = SQLite3Binary.new
+          utf8_string = "a string".encode(Encoding::UTF_8)
+          type_cast = type.type_cast_from_user(utf8_string)
+
+          assert_equal Encoding::ASCII_8BIT, type_cast.encoding
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/unconnected_test.rb b/activerecord/test/cases/unconnected_test.rb
new file mode 100644
index 0000000000..afb893a52c
--- /dev/null
+++ b/activerecord/test/cases/unconnected_test.rb
@@ -0,0 +1,33 @@
+require "cases/helper"
+
+class TestRecord < ActiveRecord::Base
+end
+
+class TestUnconnectedAdapter < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  def setup
+    @underlying = ActiveRecord::Base.connection
+    @specification = ActiveRecord::Base.remove_connection
+  end
+
+  teardown do
+    @underlying = nil
+    ActiveRecord::Base.establish_connection(@specification)
+    load_schema if in_memory_db?
+  end
+
+  def test_connection_no_longer_established
+    assert_raise(ActiveRecord::ConnectionNotEstablished) do
+      TestRecord.find(1)
+    end
+
+    assert_raise(ActiveRecord::ConnectionNotEstablished) do
+      TestRecord.new.save
+    end
+  end
+
+  def test_underlying_adapter_no_longer_active
+    assert !@underlying.active?, "Removed adapter should no longer be active"
+  end
+end
diff --git a/activerecord/test/cases/validations/association_validation_test.rb b/activerecord/test/cases/validations/association_validation_test.rb
new file mode 100644
index 0000000000..e4edc437e6
--- /dev/null
+++ b/activerecord/test/cases/validations/association_validation_test.rb
@@ -0,0 +1,86 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/reply'
+require 'models/man'
+require 'models/interest'
+
+class AssociationValidationTest < ActiveRecord::TestCase
+  fixtures :topics
+
+  repair_validations(Topic, Reply)
+
+  def test_validates_associated_many
+    Topic.validates_associated(:replies)
+    Reply.validates_presence_of(:content)
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    t.replies << [r = Reply.new("title" => "A reply"), r2 = Reply.new("title" => "Another reply", "content" => "non-empty"), r3 = Reply.new("title" => "Yet another reply"), r4 = Reply.new("title" => "The last reply", "content" => "non-empty")]
+    assert !t.valid?
+    assert t.errors[:replies].any?
+    assert_equal 1, r.errors.count  # make sure all associated objects have been validated
+    assert_equal 0, r2.errors.count
+    assert_equal 1, r3.errors.count
+    assert_equal 0, r4.errors.count
+    r.content = r3.content = "non-empty"
+    assert t.valid?
+  end
+
+  def test_validates_associated_one
+    Reply.validates :topic, :associated => true
+    Topic.validates_presence_of( :content )
+    r = Reply.new("title" => "A reply", "content" => "with content!")
+    r.topic = Topic.create("title" => "uhohuhoh")
+    assert !r.valid?
+    assert r.errors[:topic].any?
+    r.topic.content = "non-empty"
+    assert r.valid?
+  end
+
+  def test_validates_associated_marked_for_destruction
+    Topic.validates_associated(:replies)
+    Reply.validates_presence_of(:content)
+    t = Topic.new
+    t.replies << Reply.new
+    assert t.invalid?
+    t.replies.first.mark_for_destruction
+    assert t.valid?
+  end
+
+  def test_validates_associated_with_custom_message_using_quotes
+    Reply.validates_associated :topic, :message=> "This string contains 'single' and \"double\" quotes"
+    Topic.validates_presence_of :content
+    r = Reply.create("title" => "A reply", "content" => "with content!")
+    r.topic = Topic.create("title" => "uhohuhoh")
+    assert !r.valid?
+    assert_equal ["This string contains 'single' and \"double\" quotes"], r.errors[:topic]
+  end
+
+  def test_validates_associated_missing
+    Reply.validates_presence_of(:topic)
+    r = Reply.create("title" => "A reply", "content" => "with content!")
+    assert !r.valid?
+    assert r.errors[:topic].any?
+
+    r.topic = Topic.first
+    assert r.valid?
+  end
+
+  def test_validates_presence_of_belongs_to_association__parent_is_new_record
+    repair_validations(Interest) do
+      # Note that Interest and Man have the :inverse_of option set
+      Interest.validates_presence_of(:man)
+      man = Man.new(:name => 'John')
+      interest = man.interests.build(:topic => 'Airplanes')
+      assert interest.valid?, "Expected interest to be valid, but was not. Interest should have a man object associated"
+    end
+  end
+
+  def test_validates_presence_of_belongs_to_association__existing_parent
+    repair_validations(Interest) do
+      Interest.validates_presence_of(:man)
+      man = Man.create!(:name => 'John')
+      interest = man.interests.build(:topic => 'Airplanes')
+      assert interest.valid?, "Expected interest to be valid, but was not. Interest should have a man object associated"
+    end
+  end
+
+end
diff --git a/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb b/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb
new file mode 100644
index 0000000000..13d4d85afa
--- /dev/null
+++ b/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb
@@ -0,0 +1,84 @@
+require "cases/helper"
+require 'models/topic'
+
+class I18nGenerateMessageValidationTest < ActiveRecord::TestCase
+  def setup
+    Topic.clear_validators!
+    @topic = Topic.new
+    I18n.backend = I18n::Backend::Simple.new
+  end
+
+  def reset_i18n_load_path
+    @old_load_path, @old_backend = I18n.load_path.dup, I18n.backend
+    I18n.load_path.clear
+    I18n.backend = I18n::Backend::Simple.new
+    yield
+  ensure
+    I18n.load_path.replace @old_load_path
+    I18n.backend = @old_backend
+  end
+
+  # validates_associated: generate_message(attr_name, :invalid, :message => custom_message, :value => value)
+  def test_generate_message_invalid_with_default_message
+    assert_equal 'is invalid', @topic.errors.generate_message(:title, :invalid, :value => 'title')
+  end
+
+  def test_generate_message_invalid_with_custom_message
+    assert_equal 'custom message title', @topic.errors.generate_message(:title, :invalid, :message => 'custom message %{value}', :value => 'title')
+  end
+
+  # validates_uniqueness_of: generate_message(attr_name, :taken, :message => custom_message)
+  def test_generate_message_taken_with_default_message
+    assert_equal "has already been taken", @topic.errors.generate_message(:title, :taken, :value => 'title')
+  end
+
+  def test_generate_message_taken_with_custom_message
+    assert_equal 'custom message title', @topic.errors.generate_message(:title, :taken, :message => 'custom message %{value}', :value => 'title')
+  end
+
+  # ActiveRecord#RecordInvalid exception
+
+  test "RecordInvalid exception can be localized" do
+    topic = Topic.new
+    topic.errors.add(:title, :invalid)
+    topic.errors.add(:title, :blank)
+    assert_equal "Validation failed: Title is invalid, Title can't be blank", ActiveRecord::RecordInvalid.new(topic).message
+  end
+
+  test "RecordInvalid exception translation falls back to the :errors namespace" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations 'en', :errors => {:messages => {:record_invalid => 'fallback message'}}
+      topic = Topic.new
+      topic.errors.add(:title, :blank)
+      assert_equal "fallback message", ActiveRecord::RecordInvalid.new(topic).message
+    end
+  end
+
+  test "translation for 'taken' can be overridden" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", {errors: {attributes: {title: {taken: "Custom taken message" }}}}
+      assert_equal "Custom taken message", @topic.errors.generate_message(:title, :taken, :value => 'title')
+    end
+  end
+
+  test "translation for 'taken' can be overridden in activerecord scope" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", {activerecord: {errors: {messages: {taken: "Custom taken message" }}}}
+      assert_equal "Custom taken message", @topic.errors.generate_message(:title, :taken, :value => 'title')
+    end
+  end
+
+  test "translation for 'taken' can be overridden in activerecord model scope" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", {activerecord: {errors: {models: {topic: {taken: "Custom taken message" }}}}}
+      assert_equal "Custom taken message", @topic.errors.generate_message(:title, :taken, :value => 'title')
+    end
+  end
+
+  test "translation for 'taken' can be overridden in activerecord attributes scope" do
+    reset_i18n_load_path do
+      I18n.backend.store_translations "en", {activerecord: {errors: {models: {topic: {attributes: {title: {taken: "Custom taken message" }}}}}}}
+      assert_equal "Custom taken message", @topic.errors.generate_message(:title, :taken, :value => 'title')
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations/i18n_validation_test.rb b/activerecord/test/cases/validations/i18n_validation_test.rb
new file mode 100644
index 0000000000..3db742c15b
--- /dev/null
+++ b/activerecord/test/cases/validations/i18n_validation_test.rb
@@ -0,0 +1,89 @@
+require "cases/helper"
+require 'models/topic'
+require 'models/reply'
+
+class I18nValidationTest < ActiveRecord::TestCase
+  repair_validations(Topic, Reply)
+
+  def setup
+    Reply.validates_presence_of(:title)
+    @topic = Topic.new
+    @old_load_path, @old_backend = I18n.load_path.dup, I18n.backend
+    I18n.load_path.clear
+    I18n.backend = I18n::Backend::Simple.new
+    I18n.backend.store_translations('en', :errors => {:messages => {:custom => nil}})
+  end
+
+  teardown do
+    I18n.load_path.replace @old_load_path
+    I18n.backend = @old_backend
+  end
+
+  def unique_topic
+    @unique ||= Topic.create :title => 'unique!'
+  end
+
+  def replied_topic
+    @replied_topic ||= begin
+      topic = Topic.create(:title => "topic")
+      topic.replies << Reply.new
+      topic
+    end
+  end
+
+  # A set of common cases for ActiveModel::Validations message generation that
+  # are used to generate tests to keep things DRY
+  #
+  COMMON_CASES = [
+  # [ case,                                validation_options,            generate_message_options]
+    [ "given no options",                  {},                            {}],
+    [ "given custom message",              {:message => "custom"},        {:message => "custom"}],
+    [ "given if condition",                {:if     => lambda { true }},  {}],
+    [ "given unless condition",            {:unless => lambda { false }}, {}],
+    [ "given option that is not reserved", {:format => "jpg"},            {:format => "jpg" }]
+    # TODO Add :on case, but below doesn't work, because then the validation isn't run for some reason
+    #      even when using .save instead .valid?
+    # [ "given on condition",     {on: :save},                {}]
+  ]
+
+  # validates_uniqueness_of w/ mocha
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_uniqueness_of on generated message #{name}" do
+      Topic.validates_uniqueness_of :title, validation_options
+      @topic.title = unique_topic.title
+      @topic.errors.expects(:generate_message).with(:title, :taken, generate_message_options.merge(:value => 'unique!'))
+      @topic.valid?
+    end
+  end
+
+  # validates_associated w/ mocha
+
+  COMMON_CASES.each do |name, validation_options, generate_message_options|
+    test "validates_associated on generated message #{name}" do
+      Topic.validates_associated :replies, validation_options
+      replied_topic.errors.expects(:generate_message).with(:replies, :invalid, generate_message_options.merge(:value => replied_topic.replies))
+      replied_topic.save
+    end
+  end
+
+  # validates_associated w/o mocha
+
+  def test_validates_associated_finds_custom_model_key_translation
+    I18n.backend.store_translations 'en', :activerecord => {:errors => {:models => {:topic => {:attributes => {:replies => {:invalid => 'custom message'}}}}}}
+    I18n.backend.store_translations 'en', :activerecord => {:errors => {:messages => {:invalid => 'global message'}}}
+
+    Topic.validates_associated :replies
+    replied_topic.valid?
+    assert_equal ['custom message'], replied_topic.errors[:replies].uniq
+  end
+
+  def test_validates_associated_finds_global_default_translation
+    I18n.backend.store_translations 'en', :activerecord => {:errors => {:messages => {:invalid => 'global message'}}}
+
+    Topic.validates_associated :replies
+    replied_topic.valid?
+    assert_equal ['global message'], replied_topic.errors[:replies]
+  end
+
+end
diff --git a/activerecord/test/cases/validations/length_validation_test.rb b/activerecord/test/cases/validations/length_validation_test.rb
new file mode 100644
index 0000000000..4a92da38ce
--- /dev/null
+++ b/activerecord/test/cases/validations/length_validation_test.rb
@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+require "cases/helper"
+require 'models/owner'
+require 'models/pet'
+
+class LengthValidationTest < ActiveRecord::TestCase
+  fixtures :owners
+  repair_validations(Owner)
+
+  def test_validates_size_of_association
+    repair_validations Owner do
+      assert_nothing_raised { Owner.validates_size_of :pets, :minimum => 1 }
+      o = Owner.new('name' => 'nopets')
+      assert !o.save
+      assert o.errors[:pets].any?
+      o.pets.build('name' => 'apet')
+      assert o.valid?
+    end
+  end
+
+  def test_validates_size_of_association_using_within
+    repair_validations Owner do
+      assert_nothing_raised { Owner.validates_size_of :pets, :within => 1..2 }
+      o = Owner.new('name' => 'nopets')
+      assert !o.save
+      assert o.errors[:pets].any?
+
+      o.pets.build('name' => 'apet')
+      assert o.valid?
+
+      2.times { o.pets.build('name' => 'apet') }
+      assert !o.save
+      assert o.errors[:pets].any?
+    end
+  end
+
+  def test_validates_size_of_association_utf8
+    repair_validations Owner do
+      assert_nothing_raised { Owner.validates_size_of :pets, :minimum => 1 }
+      o = Owner.new('name' => 'あいうえおかきくけこ')
+      assert !o.save
+      assert o.errors[:pets].any?
+      o.pets.build('name' => 'あいうえおかきくけこ')
+      assert o.valid?
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations/presence_validation_test.rb b/activerecord/test/cases/validations/presence_validation_test.rb
new file mode 100644
index 0000000000..4f38849131
--- /dev/null
+++ b/activerecord/test/cases/validations/presence_validation_test.rb
@@ -0,0 +1,68 @@
+# encoding: utf-8
+require "cases/helper"
+require 'models/man'
+require 'models/face'
+require 'models/interest'
+require 'models/speedometer'
+require 'models/dashboard'
+
+class PresenceValidationTest < ActiveRecord::TestCase
+  class Boy < Man; end
+
+  repair_validations(Boy)
+
+  def test_validates_presence_of_non_association
+    Boy.validates_presence_of(:name)
+    b = Boy.new
+    assert b.invalid?
+
+    b.name = "Alex"
+    assert b.valid?
+  end
+
+  def test_validates_presence_of_has_one
+    Boy.validates_presence_of(:face)
+    b = Boy.new
+    assert b.invalid?, "should not be valid if has_one association missing"
+    assert_equal 1, b.errors[:face].size, "validates_presence_of should only add one error"
+  end
+
+  def test_validates_presence_of_has_one_marked_for_destruction
+    Boy.validates_presence_of(:face)
+    b = Boy.new
+    f = Face.new
+    b.face = f
+    assert b.valid?
+
+    f.mark_for_destruction
+    assert b.invalid?
+  end
+
+  def test_validates_presence_of_has_many_marked_for_destruction
+    Boy.validates_presence_of(:interests)
+    b = Boy.new
+    b.interests << [i1 = Interest.new, i2 = Interest.new]
+    assert b.valid?
+
+    i1.mark_for_destruction
+    assert b.valid?
+
+    i2.mark_for_destruction
+    assert b.invalid?
+  end
+
+  def test_validates_presence_doesnt_convert_to_array
+    speedometer = Class.new(Speedometer)
+    speedometer.validates_presence_of :dashboard
+
+    dash = Dashboard.new
+
+    # dashboard has to_a method
+    def dash.to_a; ['(/)', '(\)']; end
+
+    s = speedometer.new
+    s.dashboard = dash
+
+    assert_nothing_raised { s.valid? }
+  end
+end
diff --git a/activerecord/test/cases/validations/uniqueness_validation_test.rb b/activerecord/test/cases/validations/uniqueness_validation_test.rb
new file mode 100644
index 0000000000..18221cc73d
--- /dev/null
+++ b/activerecord/test/cases/validations/uniqueness_validation_test.rb
@@ -0,0 +1,406 @@
+# encoding: utf-8
+require "cases/helper"
+require 'models/topic'
+require 'models/reply'
+require 'models/warehouse_thing'
+require 'models/guid'
+require 'models/event'
+
+class Wizard < ActiveRecord::Base
+  self.abstract_class = true
+
+  validates_uniqueness_of :name
+end
+
+class IneptWizard < Wizard
+  validates_uniqueness_of :city
+end
+
+class Conjurer < IneptWizard
+end
+
+class Thaumaturgist < IneptWizard
+end
+
+class ReplyTitle; end
+
+class ReplyWithTitleObject < Reply
+  validates_uniqueness_of :content, :scope => :title
+
+  def title; ReplyTitle.new; end
+end
+
+class Employee < ActiveRecord::Base
+  self.table_name = 'postgresql_arrays'
+  validates_uniqueness_of :nicknames
+end
+
+class TopicWithUniqEvent < Topic
+  belongs_to :event, foreign_key: :parent_id
+  validates :event, uniqueness: true
+end
+
+class UniquenessValidationTest < ActiveRecord::TestCase
+  fixtures :topics, 'warehouse-things', :developers
+
+  repair_validations(Topic, Reply)
+
+  def test_validate_uniqueness
+    Topic.validates_uniqueness_of(:title)
+
+    t = Topic.new("title" => "I'm uniqué!")
+    assert t.save, "Should save t as unique"
+
+    t.content = "Remaining unique"
+    assert t.save, "Should still save t as unique"
+
+    t2 = Topic.new("title" => "I'm uniqué!")
+    assert !t2.valid?, "Shouldn't be valid"
+    assert !t2.save, "Shouldn't save t2 as unique"
+    assert_equal ["has already been taken"], t2.errors[:title]
+
+    t2.title = "Now I am really also unique"
+    assert t2.save, "Should now save t2 as unique"
+  end
+
+  def test_validate_uniqueness_with_alias_attribute
+    Topic.alias_attribute :new_title, :title
+    Topic.validates_uniqueness_of(:new_title)
+
+    topic = Topic.new(new_title: 'abc')
+    assert topic.valid?
+  end
+
+  def test_validates_uniqueness_with_nil_value
+    Topic.validates_uniqueness_of(:title)
+
+    t = Topic.new("title" => nil)
+    assert t.save, "Should save t as unique"
+
+    t2 = Topic.new("title" => nil)
+    assert !t2.valid?, "Shouldn't be valid"
+    assert !t2.save, "Shouldn't save t2 as unique"
+    assert_equal ["has already been taken"], t2.errors[:title]
+  end
+
+  def test_validates_uniqueness_with_validates
+    Topic.validates :title, :uniqueness => true
+    Topic.create!('title' => 'abc')
+
+    t2 = Topic.new('title' => 'abc')
+    assert !t2.valid?
+    assert t2.errors[:title]
+  end
+
+  def test_validates_uniqueness_with_newline_chars
+    Topic.validates_uniqueness_of(:title, :case_sensitive => false)
+
+    t = Topic.new("title" => "new\nline")
+    assert t.save, "Should save t as unique"
+  end
+
+  def test_validate_uniqueness_with_scope
+    Reply.validates_uniqueness_of(:content, :scope => "parent_id")
+
+    t = Topic.create("title" => "I'm unique!")
+
+    r1 = t.replies.create "title" => "r1", "content" => "hello world"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.replies.create "title" => "r2", "content" => "hello world"
+    assert !r2.valid?, "Saving r2 first time"
+
+    r2.content = "something else"
+    assert r2.save, "Saving r2 second time"
+
+    t2 = Topic.create("title" => "I'm unique too!")
+    r3 = t2.replies.create "title" => "r3", "content" => "hello world"
+    assert r3.valid?, "Saving r3"
+  end
+
+  def test_validate_uniqueness_with_object_scope
+    Reply.validates_uniqueness_of(:content, :scope => :topic)
+
+    t = Topic.create("title" => "I'm unique!")
+
+    r1 = t.replies.create "title" => "r1", "content" => "hello world"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.replies.create "title" => "r2", "content" => "hello world"
+    assert !r2.valid?, "Saving r2 first time"
+  end
+
+  def test_validate_uniqueness_with_composed_attribute_scope
+    r1 = ReplyWithTitleObject.create "title" => "r1", "content" => "hello world"
+    assert r1.valid?, "Saving r1"
+
+    r2 = ReplyWithTitleObject.create "title" => "r1", "content" => "hello world"
+    assert !r2.valid?, "Saving r2 first time"
+  end
+
+  def test_validate_uniqueness_with_object_arg
+    Reply.validates_uniqueness_of(:topic)
+
+    t = Topic.create("title" => "I'm unique!")
+
+    r1 = t.replies.create "title" => "r1", "content" => "hello world"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.replies.create "title" => "r2", "content" => "hello world"
+    assert !r2.valid?, "Saving r2 first time"
+  end
+
+  def test_validate_uniqueness_scoped_to_defining_class
+    t = Topic.create("title" => "What, me worry?")
+
+    r1 = t.unique_replies.create "title" => "r1", "content" => "a barrel of fun"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.silly_unique_replies.create "title" => "r2", "content" => "a barrel of fun"
+    assert !r2.valid?, "Saving r2"
+
+    # Should succeed as validates_uniqueness_of only applies to
+    # UniqueReply and its subclasses
+    r3 = t.replies.create "title" => "r2", "content" => "a barrel of fun"
+    assert r3.valid?, "Saving r3"
+  end
+
+  def test_validate_uniqueness_with_scope_array
+    Reply.validates_uniqueness_of(:author_name, :scope => [:author_email_address, :parent_id])
+
+    t = Topic.create("title" => "The earth is actually flat!")
+
+    r1 = t.replies.create "author_name" => "jeremy", "author_email_address" => "jeremy@rubyonrails.com", "title" => "You're crazy!", "content" => "Crazy reply"
+    assert r1.valid?, "Saving r1"
+
+    r2 = t.replies.create "author_name" => "jeremy", "author_email_address" => "jeremy@rubyonrails.com", "title" => "You're crazy!", "content" => "Crazy reply again..."
+    assert !r2.valid?, "Saving r2. Double reply by same author."
+
+    r2.author_email_address = "jeremy_alt_email@rubyonrails.com"
+    assert r2.save, "Saving r2 the second time."
+
+    r3 = t.replies.create "author_name" => "jeremy", "author_email_address" => "jeremy_alt_email@rubyonrails.com", "title" => "You're wrong", "content" => "It's cubic"
+    assert !r3.valid?, "Saving r3"
+
+    r3.author_name = "jj"
+    assert r3.save, "Saving r3 the second time."
+
+    r3.author_name = "jeremy"
+    assert !r3.save, "Saving r3 the third time."
+  end
+
+  def test_validate_case_insensitive_uniqueness
+    Topic.validates_uniqueness_of(:title, :parent_id, :case_sensitive => false, :allow_nil => true)
+
+    t = Topic.new("title" => "I'm unique!", :parent_id => 2)
+    assert t.save, "Should save t as unique"
+
+    t.content = "Remaining unique"
+    assert t.save, "Should still save t as unique"
+
+    t2 = Topic.new("title" => "I'm UNIQUE!", :parent_id => 1)
+    assert !t2.valid?, "Shouldn't be valid"
+    assert !t2.save, "Shouldn't save t2 as unique"
+    assert t2.errors[:title].any?
+    assert t2.errors[:parent_id].any?
+    assert_equal ["has already been taken"], t2.errors[:title]
+
+    t2.title = "I'm truly UNIQUE!"
+    assert !t2.valid?, "Shouldn't be valid"
+    assert !t2.save, "Shouldn't save t2 as unique"
+    assert t2.errors[:title].empty?
+    assert t2.errors[:parent_id].any?
+
+    t2.parent_id = 4
+    assert t2.save, "Should now save t2 as unique"
+
+    t2.parent_id = nil
+    t2.title = nil
+    assert t2.valid?, "should validate with nil"
+    assert t2.save, "should save with nil"
+
+    t_utf8 = Topic.new("title" => "Я тоже уникальный!")
+    assert t_utf8.save, "Should save t_utf8 as unique"
+
+    # If database hasn't UTF-8 character set, this test fails
+    if Topic.all.merge!(:select => 'LOWER(title) AS title').find(t_utf8.id).title == "я тоже уникальный!"
+      t2_utf8 = Topic.new("title" => "я тоже УНИКАЛЬНЫЙ!")
+      assert !t2_utf8.valid?, "Shouldn't be valid"
+      assert !t2_utf8.save, "Shouldn't save t2_utf8 as unique"
+    end
+  end
+
+  def test_validate_case_sensitive_uniqueness_with_special_sql_like_chars
+    Topic.validates_uniqueness_of(:title, :case_sensitive => true)
+
+    t = Topic.new("title" => "I'm unique!")
+    assert t.save, "Should save t as unique"
+
+    t2 = Topic.new("title" => "I'm %")
+    assert t2.save, "Should save t2 as unique"
+
+    t3 = Topic.new("title" => "I'm uniqu_!")
+    assert t3.save, "Should save t3 as unique"
+  end
+
+  def test_validate_case_insensitive_uniqueness_with_special_sql_like_chars
+    Topic.validates_uniqueness_of(:title, :case_sensitive => false)
+
+    t = Topic.new("title" => "I'm unique!")
+    assert t.save, "Should save t as unique"
+
+    t2 = Topic.new("title" => "I'm %")
+    assert t2.save, "Should save t2 as unique"
+
+    t3 = Topic.new("title" => "I'm uniqu_!")
+    assert t3.save, "Should save t3 as unique"
+  end
+
+  def test_validate_case_sensitive_uniqueness
+    Topic.validates_uniqueness_of(:title, :case_sensitive => true, :allow_nil => true)
+
+    t = Topic.new("title" => "I'm unique!")
+    assert t.save, "Should save t as unique"
+
+    t.content = "Remaining unique"
+    assert t.save, "Should still save t as unique"
+
+    t2 = Topic.new("title" => "I'M UNIQUE!")
+    assert t2.valid?, "Should be valid"
+    assert t2.save, "Should save t2 as unique"
+    assert t2.errors[:title].empty?
+    assert t2.errors[:parent_id].empty?
+    assert_not_equal ["has already been taken"], t2.errors[:title]
+
+    t3 = Topic.new("title" => "I'M uNiQUe!")
+    assert t3.valid?, "Should be valid"
+    assert t3.save, "Should save t2 as unique"
+    assert t3.errors[:title].empty?
+    assert t3.errors[:parent_id].empty?
+    assert_not_equal ["has already been taken"], t3.errors[:title]
+  end
+
+  def test_validate_case_sensitive_uniqueness_with_attribute_passed_as_integer
+    Topic.validates_uniqueness_of(:title, :case_sensitive => true)
+    Topic.create!('title' => 101)
+
+    t2 = Topic.new('title' => 101)
+    assert !t2.valid?
+    assert t2.errors[:title]
+  end
+
+  def test_validate_uniqueness_with_non_standard_table_names
+    i1 = WarehouseThing.create(:value => 1000)
+    assert !i1.valid?, "i1 should not be valid"
+    assert i1.errors[:value].any?, "Should not be empty"
+  end
+
+  def test_validates_uniqueness_inside_scoping
+    Topic.validates_uniqueness_of(:title)
+
+    Topic.where(:author_name => "David").scoping do
+      t1 = Topic.new("title" => "I'm unique!", "author_name" => "Mary")
+      assert t1.save
+      t2 = Topic.new("title" => "I'm unique!", "author_name" => "David")
+      assert !t2.valid?
+    end
+  end
+
+  def test_validate_uniqueness_with_columns_which_are_sql_keywords
+    repair_validations(Guid) do
+      Guid.validates_uniqueness_of :key
+      g = Guid.new
+      g.key = "foo"
+      assert_nothing_raised { !g.valid? }
+    end
+  end
+
+  def test_validate_uniqueness_with_limit
+    # Event.title is limited to 5 characters
+    e1 = Event.create(:title => "abcde")
+    assert e1.valid?, "Could not create an event with a unique, 5 character title"
+    e2 = Event.create(:title => "abcdefgh")
+    assert !e2.valid?, "Created an event whose title, with limit taken into account, is not unique"
+  end
+
+  def test_validate_uniqueness_with_limit_and_utf8
+    # Event.title is limited to 5 characters
+    e1 = Event.create(:title => "一二三四五")
+    assert e1.valid?, "Could not create an event with a unique, 5 character title"
+    e2 = Event.create(:title => "一二三四五六七八")
+    assert !e2.valid?, "Created an event whose title, with limit taken into account, is not unique"
+  end
+
+  def test_validate_straight_inheritance_uniqueness
+    w1 = IneptWizard.create(:name => "Rincewind", :city => "Ankh-Morpork")
+    assert w1.valid?, "Saving w1"
+
+    # Should use validation from base class (which is abstract)
+    w2 = IneptWizard.new(:name => "Rincewind", :city => "Quirm")
+    assert !w2.valid?, "w2 shouldn't be valid"
+    assert w2.errors[:name].any?, "Should have errors for name"
+    assert_equal ["has already been taken"], w2.errors[:name], "Should have uniqueness message for name"
+
+    w3 = Conjurer.new(:name => "Rincewind", :city => "Quirm")
+    assert !w3.valid?, "w3 shouldn't be valid"
+    assert w3.errors[:name].any?, "Should have errors for name"
+    assert_equal ["has already been taken"], w3.errors[:name], "Should have uniqueness message for name"
+
+    w4 = Conjurer.create(:name => "The Amazing Bonko", :city => "Quirm")
+    assert w4.valid?, "Saving w4"
+
+    w5 = Thaumaturgist.new(:name => "The Amazing Bonko", :city => "Lancre")
+    assert !w5.valid?, "w5 shouldn't be valid"
+    assert w5.errors[:name].any?, "Should have errors for name"
+    assert_equal ["has already been taken"], w5.errors[:name], "Should have uniqueness message for name"
+
+    w6 = Thaumaturgist.new(:name => "Mustrum Ridcully", :city => "Quirm")
+    assert !w6.valid?, "w6 shouldn't be valid"
+    assert w6.errors[:city].any?, "Should have errors for city"
+    assert_equal ["has already been taken"], w6.errors[:city], "Should have uniqueness message for city"
+  end
+
+  def test_validate_uniqueness_with_conditions
+    Topic.validates_uniqueness_of :title, conditions: -> { where(approved: true) }
+    Topic.create("title" => "I'm a topic", "approved" => true)
+    Topic.create("title" => "I'm an unapproved topic", "approved" => false)
+
+    t3 = Topic.new("title" => "I'm a topic", "approved" => true)
+    assert !t3.valid?, "t3 shouldn't be valid"
+
+    t4 = Topic.new("title" => "I'm an unapproved topic", "approved" => false)
+    assert t4.valid?, "t4 should be valid"
+  end
+
+  def test_validate_uniqueness_with_non_callable_conditions_is_not_supported
+    assert_raises(ArgumentError) {
+      Topic.validates_uniqueness_of :title, conditions: Topic.where(approved: true)
+    }
+  end
+
+  if current_adapter? :PostgreSQLAdapter
+    def test_validate_uniqueness_with_array_column
+      e1 = Employee.create("nicknames" => ["john", "johnny"], "commission_by_quarter" => [1000, 1200])
+      assert e1.persisted?, "Saving e1"
+
+      e2 = Employee.create("nicknames" => ["john", "johnny"], "commission_by_quarter" => [2200])
+      assert !e2.persisted?, "e2 shouldn't be valid"
+      assert e2.errors[:nicknames].any?, "Should have errors for nicknames"
+      assert_equal ["has already been taken"], e2.errors[:nicknames], "Should have uniqueness message for nicknames"
+    end
+  end
+
+  def test_validate_uniqueness_on_existing_relation
+    event = Event.create
+    assert TopicWithUniqEvent.create(event: event).valid?
+
+    topic = TopicWithUniqEvent.new(event: event)
+    assert_not topic.valid?
+    assert_equal ['has already been taken'], topic.errors[:event]
+  end
+
+  def test_validate_uniqueness_on_empty_relation
+    topic = TopicWithUniqEvent.new
+    assert topic.valid?
+  end
+end
diff --git a/activerecord/test/cases/validations_repair_helper.rb b/activerecord/test/cases/validations_repair_helper.rb
new file mode 100644
index 0000000000..c02b3241cd
--- /dev/null
+++ b/activerecord/test/cases/validations_repair_helper.rb
@@ -0,0 +1,23 @@
+module ActiveRecord
+  module ValidationsRepairHelper
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def repair_validations(*model_classes)
+        teardown do
+          model_classes.each do |k|
+            k.clear_validators!
+          end
+        end
+      end
+    end
+
+    def repair_validations(*model_classes)
+      yield
+    ensure
+      model_classes.each do |k|
+        k.clear_validators!
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/validations_test.rb b/activerecord/test/cases/validations_test.rb
new file mode 100644
index 0000000000..55804f9576
--- /dev/null
+++ b/activerecord/test/cases/validations_test.rb
@@ -0,0 +1,151 @@
+# encoding: utf-8
+require "cases/helper"
+require 'models/topic'
+require 'models/reply'
+require 'models/person'
+require 'models/developer'
+require 'models/parrot'
+require 'models/company'
+
+class ValidationsTest < ActiveRecord::TestCase
+  fixtures :topics, :developers
+
+  # Most of the tests mess with the validations of Topic, so lets repair it all the time.
+  # Other classes we mess with will be dealt with in the specific tests
+  repair_validations(Topic)
+
+  def test_valid_uses_create_context_when_new
+    r = WrongReply.new
+    r.title = "Wrong Create"
+    assert_not r.valid?
+    assert r.errors[:title].any?, "A reply with a bad title should mark that attribute as invalid"
+    assert_equal ["is Wrong Create"], r.errors[:title], "A reply with a bad content should contain an error"
+  end
+
+  def test_valid_uses_update_context_when_persisted
+    r = WrongReply.new
+    r.title = "Bad"
+    r.content = "Good"
+    assert r.save, "First validation should be successful"
+
+    r.title = "Wrong Update"
+    assert_not r.valid?, "Second validation should fail"
+
+    assert r.errors[:title].any?, "A reply with a bad title should mark that attribute as invalid"
+    assert_equal ["is Wrong Update"], r.errors[:title], "A reply with a bad content should contain an error"
+  end
+
+  def test_valid_using_special_context
+    r = WrongReply.new(:title => "Valid title")
+    assert !r.valid?(:special_case)
+    assert_equal "Invalid", r.errors[:author_name].join
+
+    r.author_name = "secret"
+    r.content = "Good"
+    assert r.valid?(:special_case)
+
+    r.author_name = nil
+    assert_not r.valid?(:special_case)
+    assert_equal "Invalid", r.errors[:author_name].join
+
+    r.author_name = "secret"
+    assert r.valid?(:special_case)
+  end
+
+  def test_validate
+    r = WrongReply.new
+
+    r.validate
+    assert_empty r.errors[:author_name]
+
+    r.validate(:special_case)
+    assert_not_empty r.errors[:author_name]
+
+    r.author_name = "secret"
+
+    r.validate(:special_case)
+    assert_empty r.errors[:author_name]
+  end
+
+  def test_invalid_record_exception
+    assert_raise(ActiveRecord::RecordInvalid) { WrongReply.create! }
+    assert_raise(ActiveRecord::RecordInvalid) { WrongReply.new.save! }
+
+    r = WrongReply.new
+    invalid = assert_raise ActiveRecord::RecordInvalid do
+      r.save!
+    end
+    assert_equal r, invalid.record
+  end
+
+  def test_validate_with_bang
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.new.validate!
+    end
+  end
+
+  def test_validate_with_bang_and_context
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.new.validate!(:special_case)
+    end
+    r = WrongReply.new(:title => "Valid title", :author_name => "secret", :content => "Good")
+    assert r.validate!(:special_case)
+  end
+
+  def test_exception_on_create_bang_many
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.create!([ { "title" => "OK" }, { "title" => "Wrong Create" }])
+    end
+  end
+
+  def test_exception_on_create_bang_with_block
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.create!({ "title" => "OK" }) do |r|
+        r.content = nil
+      end
+    end
+  end
+
+  def test_exception_on_create_bang_many_with_block
+    assert_raise(ActiveRecord::RecordInvalid) do
+      WrongReply.create!([{ "title" => "OK" }, { "title" => "Wrong Create" }]) do |r|
+        r.content = nil
+      end
+    end
+  end
+
+  def test_save_without_validation
+    reply = WrongReply.new
+    assert !reply.save
+    assert reply.save(:validate => false)
+  end
+
+  def test_validates_acceptance_of_with_non_existent_table
+    Object.const_set :IncorporealModel, Class.new(ActiveRecord::Base)
+
+    assert_nothing_raised ActiveRecord::StatementInvalid do
+      IncorporealModel.validates_acceptance_of(:incorporeal_column)
+    end
+  end
+
+  def test_throw_away_typing
+    d = Developer.new("name" => "David", "salary" => "100,000")
+    assert !d.valid?
+    assert_equal 100, d.salary
+    assert_equal "100,000", d.salary_before_type_cast
+  end
+
+  def test_validates_acceptance_of_as_database_column
+    Topic.validates_acceptance_of(:approved)
+    topic = Topic.create("approved" => true)
+    assert topic["approved"]
+  end
+
+  def test_validators
+    assert_equal 1, Parrot.validators.size
+    assert_equal 1, Company.validators.size
+    assert_equal 1, Parrot.validators_on(:name).size
+    assert_equal 1, Company.validators_on(:name).size
+  end
+
+end
diff --git a/activerecord/test/cases/xml_serialization_test.rb b/activerecord/test/cases/xml_serialization_test.rb
new file mode 100644
index 0000000000..c34e7d5a30
--- /dev/null
+++ b/activerecord/test/cases/xml_serialization_test.rb
@@ -0,0 +1,447 @@
+require "cases/helper"
+require "rexml/document"
+require 'models/contact'
+require 'models/post'
+require 'models/author'
+require 'models/comment'
+require 'models/company_in_module'
+require 'models/toy'
+require 'models/topic'
+require 'models/reply'
+require 'models/company'
+
+class XmlSerializationTest < ActiveRecord::TestCase
+  def test_should_serialize_default_root
+    @xml = Contact.new.to_xml
+    assert_match %r{^<contact>},  @xml
+    assert_match %r{</contact>$}, @xml
+  end
+
+  def test_should_serialize_default_root_with_namespace
+    @xml = Contact.new.to_xml :namespace=>"http://xml.rubyonrails.org/contact"
+    assert_match %r{^<contact xmlns="http://xml.rubyonrails.org/contact">},  @xml
+    assert_match %r{</contact>$}, @xml
+  end
+
+  def test_should_serialize_custom_root
+    @xml = Contact.new.to_xml :root => 'xml_contact'
+    assert_match %r{^<xml-contact>},  @xml
+    assert_match %r{</xml-contact>$}, @xml
+  end
+
+  def test_should_allow_undasherized_tags
+    @xml = Contact.new.to_xml :root => 'xml_contact', :dasherize => false
+    assert_match %r{^<xml_contact>},  @xml
+    assert_match %r{</xml_contact>$}, @xml
+    assert_match %r{<created_at},     @xml
+  end
+
+  def test_should_allow_camelized_tags
+    @xml = Contact.new.to_xml :root => 'xml_contact', :camelize => true
+    assert_match %r{^<XmlContact>},  @xml
+    assert_match %r{</XmlContact>$}, @xml
+    assert_match %r{<CreatedAt},    @xml
+  end
+
+  def test_should_allow_skipped_types
+    @xml = Contact.new(:age => 25).to_xml :skip_types => true
+    assert %r{<age>25</age>}.match(@xml)
+  end
+
+  def test_should_include_yielded_additions
+    @xml = Contact.new.to_xml do |xml|
+      xml.creator "David"
+    end
+    assert_match %r{<creator>David</creator>}, @xml
+  end
+
+  def test_to_xml_with_block
+    value = "Rockin' the block"
+    xml = Contact.new.to_xml(:skip_instruct => true) do |_xml|
+      _xml.tag! "arbitrary-element", value
+    end
+    assert_equal "<contact>", xml.first(9)
+    assert xml.include?(%(<arbitrary-element>#{value}</arbitrary-element>))
+  end
+
+  def test_should_skip_instruct_for_included_records
+    @contact = Contact.new
+    @contact.alternative = Contact.new(:name => 'Copa Cabana')
+    @xml = @contact.to_xml(:include => [ :alternative ])
+    assert_equal @xml.index('<?xml '), 0
+    assert_nil @xml.index('<?xml ', 1)
+  end
+end
+
+class DefaultXmlSerializationTest < ActiveRecord::TestCase
+  def setup
+    @contact = Contact.new(
+      :name        => 'aaron stack',
+      :age         => 25,
+      :avatar      => 'binarydata',
+      :created_at  => Time.utc(2006, 8, 1),
+      :awesome     => false,
+      :preferences => { :gem => 'ruby' }
+    )
+  end
+
+  def test_should_serialize_string
+    assert_match %r{<name>aaron stack</name>}, @contact.to_xml
+  end
+
+  def test_should_serialize_integer
+    assert_match %r{<age type="integer">25</age>}, @contact.to_xml
+  end
+
+  def test_should_serialize_binary
+    xml = @contact.to_xml
+    assert_match %r{YmluYXJ5ZGF0YQ==\n</avatar>},    xml
+    assert_match %r{<avatar(.*)(type="binary")},     xml
+    assert_match %r{<avatar(.*)(encoding="base64")}, xml
+  end
+
+  def test_should_serialize_datetime
+    assert_match %r{<created-at type=\"dateTime\">2006-08-01T00:00:00Z</created-at>}, @contact.to_xml
+  end
+
+  def test_should_serialize_boolean
+    assert_match %r{<awesome type=\"boolean\">false</awesome>}, @contact.to_xml
+  end
+
+  def test_should_serialize_hash
+    assert_match %r{<preferences>\s*<gem>ruby</gem>\s*</preferences>}m, @contact.to_xml
+  end
+
+  def test_uses_serializable_hash_with_only_option
+    def @contact.serializable_hash(options=nil)
+      super(only: %w(name))
+    end
+
+    xml = @contact.to_xml
+    assert_match %r{<name>aaron stack</name>}, xml
+    assert_no_match %r{age}, xml
+    assert_no_match %r{awesome}, xml
+  end
+
+  def test_uses_serializable_hash_with_except_option
+    def @contact.serializable_hash(options=nil)
+      super(except: %w(age))
+    end
+
+    xml = @contact.to_xml
+    assert_match %r{<name>aaron stack</name>}, xml
+    assert_match %r{<awesome type=\"boolean\">false</awesome>}, xml
+    assert_no_match %r{age}, xml
+  end
+
+  def test_does_not_include_inheritance_column_from_sti
+    @contact = ContactSti.new(@contact.attributes)
+    assert_equal 'ContactSti', @contact.type
+
+    xml = @contact.to_xml
+    assert_match %r{<name>aaron stack</name>}, xml
+    assert_no_match %r{<type}, xml
+    assert_no_match %r{ContactSti}, xml
+  end
+
+  def test_serializable_hash_with_default_except_option_and_excluding_inheritance_column_from_sti
+    @contact = ContactSti.new(@contact.attributes)
+    assert_equal 'ContactSti', @contact.type
+
+    def @contact.serializable_hash(options={})
+      super({ except: %w(age) }.merge!(options))
+    end
+
+    xml = @contact.to_xml
+    assert_match %r{<name>aaron stack</name>}, xml
+    assert_no_match %r{age}, xml
+    assert_no_match %r{<type}, xml
+    assert_no_match %r{ContactSti}, xml
+  end
+end
+
+class DefaultXmlSerializationTimezoneTest < ActiveRecord::TestCase
+  def test_should_serialize_datetime_with_timezone
+    with_timezone_config zone: "Pacific Time (US & Canada)" do
+      toy = Toy.create(:name => 'Mickey', :updated_at => Time.utc(2006, 8, 1))
+      assert_match %r{<updated-at type=\"dateTime\">2006-07-31T17:00:00-07:00</updated-at>}, toy.to_xml
+    end
+  end
+
+  def test_should_serialize_datetime_with_timezone_reloaded
+    with_timezone_config zone: "Pacific Time (US & Canada)" do
+      toy = Toy.create(:name => 'Minnie', :updated_at => Time.utc(2006, 8, 1)).reload
+      assert_match %r{<updated-at type=\"dateTime\">2006-07-31T17:00:00-07:00</updated-at>}, toy.to_xml
+    end
+  end
+end
+
+class NilXmlSerializationTest < ActiveRecord::TestCase
+  def setup
+    @xml = Contact.new.to_xml(:root => 'xml_contact')
+  end
+
+  def test_should_serialize_string
+    assert_match %r{<name nil="true"/>}, @xml
+  end
+
+  def test_should_serialize_integer
+    assert %r{<age (.*)/>}.match(@xml)
+    attributes = $1
+    assert_match %r{nil="true"}, attributes
+    assert_match %r{type="integer"}, attributes
+  end
+
+  def test_should_serialize_binary
+    assert %r{<avatar (.*)/>}.match(@xml)
+    attributes = $1
+    assert_match %r{type="binary"}, attributes
+    assert_match %r{encoding="base64"}, attributes
+    assert_match %r{nil="true"}, attributes
+  end
+
+  def test_should_serialize_datetime
+    assert %r{<created-at (.*)/>}.match(@xml)
+    attributes = $1
+    assert_match %r{nil="true"}, attributes
+    assert_match %r{type="dateTime"}, attributes
+  end
+
+  def test_should_serialize_boolean
+    assert %r{<awesome (.*)/>}.match(@xml)
+    attributes = $1
+    assert_match %r{type="boolean"}, attributes
+    assert_match %r{nil="true"}, attributes
+  end
+
+  def test_should_serialize_yaml
+    assert_match %r{<preferences nil=\"true\"/>}, @xml
+  end
+end
+
+class DatabaseConnectedXmlSerializationTest < ActiveRecord::TestCase
+  fixtures :topics, :companies, :accounts, :authors, :posts, :projects
+
+  def test_to_xml
+    xml = REXML::Document.new(topics(:first).to_xml(:indent => 0))
+    bonus_time_in_current_timezone = topics(:first).bonus_time.xmlschema
+    written_on_in_current_timezone = topics(:first).written_on.xmlschema
+
+    assert_equal "topic", xml.root.name
+    assert_equal "The First Topic" , xml.elements["//title"].text
+    assert_equal "David" , xml.elements["//author-name"].text
+    assert_match "Have a nice day", xml.elements["//content"].text
+
+    assert_equal "1", xml.elements["//id"].text
+    assert_equal "integer" , xml.elements["//id"].attributes['type']
+
+    assert_equal "1", xml.elements["//replies-count"].text
+    assert_equal "integer" , xml.elements["//replies-count"].attributes['type']
+
+    assert_equal written_on_in_current_timezone, xml.elements["//written-on"].text
+    assert_equal "dateTime" , xml.elements["//written-on"].attributes['type']
+
+    assert_equal "david@loudthinking.com", xml.elements["//author-email-address"].text
+
+    assert_equal nil, xml.elements["//parent-id"].text
+    assert_equal "integer", xml.elements["//parent-id"].attributes['type']
+    assert_equal "true", xml.elements["//parent-id"].attributes['nil']
+
+    # Oracle enhanced adapter allows to define Date attributes in model class (see topic.rb)
+    assert_equal "2004-04-15", xml.elements["//last-read"].text
+    assert_equal "date" , xml.elements["//last-read"].attributes['type']
+
+    # Oracle and DB2 don't have true boolean or time-only fields
+    unless current_adapter?(:OracleAdapter, :DB2Adapter)
+      assert_equal "false", xml.elements["//approved"].text
+      assert_equal "boolean" , xml.elements["//approved"].attributes['type']
+
+      assert_equal bonus_time_in_current_timezone, xml.elements["//bonus-time"].text
+      assert_equal "dateTime" , xml.elements["//bonus-time"].attributes['type']
+    end
+  end
+
+  def test_except_option
+    xml = topics(:first).to_xml(:indent => 0, :skip_instruct => true, :except => [:title, :replies_count])
+    assert_equal "<topic>", xml.first(7)
+    assert !xml.include?(%(<title>The First Topic</title>))
+    assert xml.include?(%(<author-name>David</author-name>))
+
+    xml = topics(:first).to_xml(:indent => 0, :skip_instruct => true, :except => [:title, :author_name, :replies_count])
+    assert !xml.include?(%(<title>The First Topic</title>))
+    assert !xml.include?(%(<author-name>David</author-name>))
+  end
+
+  # to_xml used to mess with the hash the user provided which
+  # caused the builder to be reused.  This meant the document kept
+  # getting appended to.
+
+  def test_modules
+    projects = MyApplication::Business::Project.all
+    xml = projects.to_xml
+    root = projects.first.class.to_s.underscore.pluralize.tr('/','_').dasherize
+    assert_match "<#{root} type=\"array\">", xml
+    assert_match "</#{root}>", xml
+  end
+
+  def test_passing_hash_shouldnt_reuse_builder
+    options = {:include=>:posts}
+    david = authors(:david)
+    first_xml_size = david.to_xml(options).size
+    second_xml_size = david.to_xml(options).size
+    assert_equal first_xml_size, second_xml_size
+  end
+
+  def test_include_uses_association_name
+    xml = authors(:david).to_xml :include=>:hello_posts, :indent => 0
+    assert_match %r{<hello-posts type="array">}, xml
+    assert_match %r{<hello-post type="Post">}, xml
+    assert_match %r{<hello-post type="StiPost">}, xml
+  end
+
+  def test_included_associations_should_skip_types
+    xml = authors(:david).to_xml :include=>:hello_posts, :indent => 0, :skip_types => true
+    assert_match %r{<hello-posts>}, xml
+    assert_match %r{<hello-post>}, xml
+    assert_match %r{<hello-post>}, xml
+  end
+
+  def test_including_has_many_association
+    xml = topics(:first).to_xml(:indent => 0, :skip_instruct => true, :include => :replies, :except => :replies_count)
+    assert_equal "<topic>", xml.first(7)
+    assert xml.include?(%(<replies type="array"><reply>))
+    assert xml.include?(%(<title>The Second Topic of the day</title>))
+  end
+
+  def test_including_belongs_to_association
+    xml = companies(:first_client).to_xml(:indent => 0, :skip_instruct => true, :include => :firm)
+    assert !xml.include?("<firm>")
+
+    xml = companies(:second_client).to_xml(:indent => 0, :skip_instruct => true, :include => :firm)
+    assert xml.include?("<firm>")
+  end
+
+  def test_including_multiple_associations
+    xml = companies(:first_firm).to_xml(:indent => 0, :skip_instruct => true, :include => [ :clients, :account ])
+    assert_equal "<firm>", xml.first(6)
+    assert xml.include?(%(<account>))
+    assert xml.include?(%(<clients type="array"><client>))
+  end
+
+  def test_including_association_with_options
+    xml = companies(:first_firm).to_xml(
+      :indent  => 0, :skip_instruct => true,
+      :include => { :clients => { :only => :name } }
+    )
+
+    assert_equal "<firm>", xml.first(6)
+    assert xml.include?(%(<client><name>Summit</name></client>))
+    assert xml.include?(%(<clients type="array"><client>))
+  end
+
+  def test_methods_are_called_on_object
+    xml = authors(:david).to_xml :methods => :label, :indent => 0
+    assert_match %r{<label>.*</label>}, xml
+  end
+
+  def test_should_not_call_methods_on_associations_that_dont_respond
+    xml = authors(:david).to_xml :include=>:hello_posts, :methods => :label, :indent => 2
+    assert !authors(:david).hello_posts.first.respond_to?(:label)
+    assert_match %r{^  <label>.*</label>}, xml
+    assert_no_match %r{^      <label>}, xml
+  end
+
+  def test_procs_are_called_on_object
+    proc = Proc.new { |options| options[:builder].tag!('nationality', 'Danish') }
+    xml = authors(:david).to_xml(:procs => [ proc ])
+    assert_match %r{<nationality>Danish</nationality>}, xml
+  end
+
+  def test_dual_arity_procs_are_called_on_object
+    proc = Proc.new { |options, record| options[:builder].tag!('name-reverse', record.name.reverse) }
+    xml = authors(:david).to_xml(:procs => [ proc ])
+    assert_match %r{<name-reverse>divaD</name-reverse>}, xml
+  end
+
+  def test_top_level_procs_arent_applied_to_associations
+    author_proc = Proc.new { |options| options[:builder].tag!('nationality', 'Danish') }
+    xml = authors(:david).to_xml(:procs => [ author_proc ], :include => :posts, :indent => 2)
+
+    assert_match %r{^  <nationality>Danish</nationality>}, xml
+    assert_no_match %r{^ {6}<nationality>Danish</nationality>}, xml
+  end
+
+  def test_procs_on_included_associations_are_called
+    posts_proc = Proc.new { |options| options[:builder].tag!('copyright', 'DHH') }
+    xml = authors(:david).to_xml(
+      :indent => 2,
+      :include => {
+        :posts => { :procs => [ posts_proc ] }
+      }
+    )
+
+    assert_no_match %r{^  <copyright>DHH</copyright>}, xml
+    assert_match %r{^ {6}<copyright>DHH</copyright>}, xml
+  end
+
+  def test_should_include_empty_has_many_as_empty_array
+    authors(:david).posts.delete_all
+    xml = authors(:david).to_xml :include=>:posts, :indent => 2
+
+    assert_equal [], Hash.from_xml(xml)['author']['posts']
+    assert_match %r{^  <posts type="array"/>}, xml
+  end
+
+  def test_should_has_many_array_elements_should_include_type_when_different_from_guessed_value
+    xml = authors(:david).to_xml :include=>:posts_with_comments, :indent => 2
+
+    assert Hash.from_xml(xml)
+    assert_match %r{^  <posts-with-comments type="array">}, xml
+    assert_match %r{^    <posts-with-comment type="Post">}, xml
+    assert_match %r{^    <posts-with-comment type="StiPost">}, xml
+
+    types = Hash.from_xml(xml)['author']['posts_with_comments'].collect {|t| t['type'] }
+    assert types.include?('SpecialPost')
+    assert types.include?('Post')
+    assert types.include?('StiPost')
+  end
+
+  def test_should_produce_xml_for_methods_returning_array
+    xml = authors(:david).to_xml(:methods => :social)
+    array = Hash.from_xml(xml)['author']['social']
+    assert_equal 2, array.size
+    assert array.include? 'twitter'
+    assert array.include? 'github'
+  end
+
+  def test_should_support_aliased_attributes
+    xml = Author.select("name as firstname").to_xml
+    Author.all.each do |author|
+      assert xml.include?(%(<firstname>#{author.name}</firstname>)), xml
+    end
+  end
+
+  def test_array_to_xml_including_has_many_association
+    xml = [ topics(:first), topics(:second) ].to_xml(:indent => 0, :skip_instruct => true, :include => :replies)
+    assert xml.include?(%(<replies type="array"><reply>))
+  end
+
+  def test_array_to_xml_including_methods
+    xml = [ topics(:first), topics(:second) ].to_xml(:indent => 0, :skip_instruct => true, :methods => [ :topic_id ])
+    assert xml.include?(%(<topic-id type="integer">#{topics(:first).topic_id}</topic-id>)), xml
+    assert xml.include?(%(<topic-id type="integer">#{topics(:second).topic_id}</topic-id>)), xml
+  end
+
+  def test_array_to_xml_including_has_one_association
+    xml = [ companies(:first_firm), companies(:rails_core) ].to_xml(:indent => 0, :skip_instruct => true, :include => :account)
+    assert xml.include?(companies(:first_firm).account.to_xml(:indent => 0, :skip_instruct => true))
+    assert xml.include?(companies(:rails_core).account.to_xml(:indent => 0, :skip_instruct => true))
+  end
+
+  def test_array_to_xml_including_belongs_to_association
+    xml = [ companies(:first_client), companies(:second_client), companies(:another_client) ].to_xml(:indent => 0, :skip_instruct => true, :include => :firm)
+    assert xml.include?(companies(:first_client).to_xml(:indent => 0, :skip_instruct => true))
+    assert xml.include?(companies(:second_client).firm.to_xml(:indent => 0, :skip_instruct => true))
+    assert xml.include?(companies(:another_client).firm.to_xml(:indent => 0, :skip_instruct => true))
+  end
+end
diff --git a/activerecord/test/cases/yaml_serialization_test.rb b/activerecord/test/cases/yaml_serialization_test.rb
new file mode 100644
index 0000000000..bce59b4fcd
--- /dev/null
+++ b/activerecord/test/cases/yaml_serialization_test.rb
@@ -0,0 +1,86 @@
+require 'cases/helper'
+require 'models/topic'
+require 'models/reply'
+require 'models/post'
+require 'models/author'
+
+class YamlSerializationTest < ActiveRecord::TestCase
+  fixtures :topics, :authors, :posts
+
+  def test_to_yaml_with_time_with_zone_should_not_raise_exception
+    with_timezone_config aware_attributes: true, zone: "Pacific Time (US & Canada)" do
+      topic = Topic.new(:written_on => DateTime.now)
+      assert_nothing_raised { topic.to_yaml }
+    end
+  end
+
+  def test_roundtrip
+    topic = Topic.first
+    assert topic
+    t = YAML.load YAML.dump topic
+    assert_equal topic, t
+  end
+
+  def test_roundtrip_serialized_column
+    topic = Topic.new(:content => {:omg=>:lol})
+    assert_equal({:omg=>:lol}, YAML.load(YAML.dump(topic)).content)
+  end
+
+  def test_psych_roundtrip
+    topic = Topic.first
+    assert topic
+    t = Psych.load Psych.dump topic
+    assert_equal topic, t
+  end
+
+  def test_psych_roundtrip_new_object
+    topic = Topic.new
+    assert topic
+    t = Psych.load Psych.dump topic
+    assert_equal topic.attributes, t.attributes
+  end
+
+  def test_active_record_relation_serialization
+    [Topic.all].to_yaml
+  end
+
+  def test_raw_types_are_not_changed_on_round_trip
+    topic = Topic.new(parent_id: "123")
+    assert_equal "123", topic.parent_id_before_type_cast
+    assert_equal "123", YAML.load(YAML.dump(topic)).parent_id_before_type_cast
+  end
+
+  def test_cast_types_are_not_changed_on_round_trip
+    topic = Topic.new(parent_id: "123")
+    assert_equal 123, topic.parent_id
+    assert_equal 123, YAML.load(YAML.dump(topic)).parent_id
+  end
+
+  def test_new_records_remain_new_after_round_trip
+    topic = Topic.new
+
+    assert topic.new_record?, "Sanity check that new records are new"
+    assert YAML.load(YAML.dump(topic)).new_record?, "Record should be new after deserialization"
+
+    topic.save!
+
+    assert_not topic.new_record?, "Saved records are not new"
+    assert_not YAML.load(YAML.dump(topic)).new_record?, "Saved record should not be new after deserialization"
+
+    topic = Topic.select('title').last
+
+    assert_not topic.new_record?, "Loaded records without ID are not new"
+    assert_not YAML.load(YAML.dump(topic)).new_record?, "Record should not be new after deserialization"
+  end
+
+  def test_types_of_virtual_columns_are_not_changed_on_round_trip
+    author = Author.select('authors.*, count(posts.id) as posts_count')
+      .joins(:posts)
+      .group('authors.id')
+      .first
+    dumped = YAML.load(YAML.dump(author))
+
+    assert_equal 5, author.posts_count
+    assert_equal 5, dumped.posts_count
+  end
+end
diff --git a/activerecord/test/config.example.yml b/activerecord/test/config.example.yml
new file mode 100644
index 0000000000..a54914c372
--- /dev/null
+++ b/activerecord/test/config.example.yml
@@ -0,0 +1,110 @@
+default_connection: <%= defined?(JRUBY_VERSION) ? 'jdbcsqlite3' : 'sqlite3' %>
+
+with_manual_interventions: false
+
+connections:
+  jdbcderby:
+    arunit:  activerecord_unittest
+    arunit2: activerecord_unittest2
+
+  jdbch2:
+    arunit:  activerecord_unittest
+    arunit2: activerecord_unittest2
+
+  jdbchsqldb:
+    arunit:  activerecord_unittest
+    arunit2: activerecord_unittest2
+
+  jdbcmysql:
+    arunit:
+      username: rails
+      encoding: utf8
+    arunit2:
+      username: rails
+      encoding: utf8
+
+  jdbcpostgresql:
+    arunit:
+      username: <%= ENV['user'] || 'rails' %>
+    arunit2:
+      username: <%= ENV['user'] || 'rails' %>
+
+  jdbcsqlite3:
+    arunit:
+      database: <%= FIXTURES_ROOT %>/fixture_database.sqlite3
+      timeout:  5000
+    arunit2:
+      database: <%= FIXTURES_ROOT %>/fixture_database_2.sqlite3
+      timeout:  5000
+
+  db2:
+    arunit:
+      adapter:  ibm_db
+      host:     localhost
+      username: arunit
+      password: arunit
+      database: arunit
+    arunit2:
+      adapter:  ibm_db
+      host:     localhost
+      username: arunit
+      password: arunit
+      database: arunit2
+
+  mysql:
+    arunit:
+      username: rails
+      encoding: utf8
+    arunit2:
+      username: rails
+      encoding: utf8
+
+  mysql2:
+    arunit:
+      username: rails
+      encoding: utf8
+    arunit2:
+      username: rails
+      encoding: utf8
+
+  openbase:
+    arunit:
+      username: admin
+    arunit2:
+      username: admin
+
+  oracle:
+     arunit:
+       adapter: oracle_enhanced
+       database: <%= ENV['ARUNIT_DB_NAME'] || 'orcl' %>
+       username: <%= ENV['ARUNIT_USER_NAME'] || 'arunit' %>
+       password: <%= ENV['ARUNIT_PASSWORD'] || 'arunit' %>
+       emulate_oracle_adapter: true
+     arunit2:
+       adapter: oracle_enhanced
+       database: <%= ENV['ARUNIT_DB_NAME'] || 'orcl' %>
+       username: <%= ENV['ARUNIT2_USER_NAME'] || 'arunit2' %>
+       password: <%= ENV['ARUNIT2_PASSWORD'] || 'arunit2' %>
+       emulate_oracle_adapter: true
+
+  postgresql:
+    arunit:
+      min_messages: warning
+    arunit2:
+      min_messages: warning
+
+  sqlite3:
+    arunit:
+      database: <%= FIXTURES_ROOT %>/fixture_database.sqlite3
+      timeout:  5000
+    arunit2:
+      database: <%= FIXTURES_ROOT %>/fixture_database_2.sqlite3
+      timeout:  5000
+
+  sqlite3_mem:
+    arunit:
+      adapter: sqlite3
+      database: ':memory:'
+    arunit2:
+      adapter: sqlite3
+      database: ':memory:'
diff --git a/activerecord/test/config.rb b/activerecord/test/config.rb
new file mode 100644
index 0000000000..6e2e8b2145
--- /dev/null
+++ b/activerecord/test/config.rb
@@ -0,0 +1,5 @@
+TEST_ROOT       = File.expand_path(File.dirname(__FILE__))
+ASSETS_ROOT     = TEST_ROOT + "/assets"
+FIXTURES_ROOT   = TEST_ROOT + "/fixtures"
+MIGRATIONS_ROOT = TEST_ROOT + "/migrations"
+SCHEMA_ROOT     = TEST_ROOT + "/schema"
diff --git a/activerecord/test/fixtures/.gitignore b/activerecord/test/fixtures/.gitignore
new file mode 100644
index 0000000000..885029a512
--- /dev/null
+++ b/activerecord/test/fixtures/.gitignore
@@ -0,0 +1 @@
+*.sqlite*
\ No newline at end of file
diff --git a/activerecord/test/fixtures/accounts.yml b/activerecord/test/fixtures/accounts.yml
new file mode 100644
index 0000000000..32583042a8
--- /dev/null
+++ b/activerecord/test/fixtures/accounts.yml
@@ -0,0 +1,29 @@
+signals37:
+  id: 1
+  firm_id: 1
+  credit_limit: 50
+  firm_name: 37signals
+
+unknown:
+  id: 2
+  credit_limit: 50
+
+rails_core_account:
+  id: 3
+  firm_id: 6
+  credit_limit: 50
+
+last_account:
+  id: 4
+  firm_id: 2
+  credit_limit: 60
+
+rails_core_account_2:
+  id: 5
+  firm_id: 6
+  credit_limit: 55
+
+odegy_account:
+  id: 6
+  firm_id: 9
+  credit_limit: 53
diff --git a/activerecord/test/fixtures/admin/accounts.yml b/activerecord/test/fixtures/admin/accounts.yml
new file mode 100644
index 0000000000..9e341a15af
--- /dev/null
+++ b/activerecord/test/fixtures/admin/accounts.yml
@@ -0,0 +1,2 @@
+signals37:
+  name: 37signals
diff --git a/activerecord/test/fixtures/admin/randomly_named_a9.yml b/activerecord/test/fixtures/admin/randomly_named_a9.yml
new file mode 100644
index 0000000000..bc51c83112
--- /dev/null
+++ b/activerecord/test/fixtures/admin/randomly_named_a9.yml
@@ -0,0 +1,7 @@
+first_instance:

+  some_attribute: AAA

+  another_attribute: 000

+

+second_instance:

+  some_attribute: BBB

+  another_attribute: 999

diff --git a/activerecord/test/fixtures/admin/randomly_named_b0.yml b/activerecord/test/fixtures/admin/randomly_named_b0.yml
new file mode 100644
index 0000000000..bc51c83112
--- /dev/null
+++ b/activerecord/test/fixtures/admin/randomly_named_b0.yml
@@ -0,0 +1,7 @@
+first_instance:

+  some_attribute: AAA

+  another_attribute: 000

+

+second_instance:

+  some_attribute: BBB

+  another_attribute: 999

diff --git a/activerecord/test/fixtures/admin/users.yml b/activerecord/test/fixtures/admin/users.yml
new file mode 100644
index 0000000000..e2884beda5
--- /dev/null
+++ b/activerecord/test/fixtures/admin/users.yml
@@ -0,0 +1,10 @@
+david:
+  name: David
+  account: signals37
+
+jamis:
+  name: Jamis
+  account: signals37
+  settings:
+    :symbol: symbol
+    string: string
diff --git a/activerecord/test/fixtures/all/admin b/activerecord/test/fixtures/all/admin
new file mode 120000
index 0000000000..984d12a043
--- /dev/null
+++ b/activerecord/test/fixtures/all/admin
@@ -0,0 +1 @@
+../to_be_linked/
\ No newline at end of file
diff --git a/activerecord/test/fixtures/all/developers.yml b/activerecord/test/fixtures/all/developers.yml
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activerecord/test/fixtures/all/developers.yml
diff --git a/activerecord/test/fixtures/all/people.yml b/activerecord/test/fixtures/all/people.yml
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activerecord/test/fixtures/all/people.yml
diff --git a/activerecord/test/fixtures/all/tasks.yml b/activerecord/test/fixtures/all/tasks.yml
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activerecord/test/fixtures/all/tasks.yml
diff --git a/activerecord/test/fixtures/author_addresses.yml b/activerecord/test/fixtures/author_addresses.yml
new file mode 100644
index 0000000000..7b90572187
--- /dev/null
+++ b/activerecord/test/fixtures/author_addresses.yml
@@ -0,0 +1,5 @@
+david_address:
+  id: 1
+
+david_address_extra:
+  id: 2
diff --git a/activerecord/test/fixtures/author_favorites.yml b/activerecord/test/fixtures/author_favorites.yml
new file mode 100644
index 0000000000..e81fdac778
--- /dev/null
+++ b/activerecord/test/fixtures/author_favorites.yml
@@ -0,0 +1,4 @@
+david_mary:
+  id: 1
+  author_id: 1
+  favorite_author_id: 2
\ No newline at end of file
diff --git a/activerecord/test/fixtures/authors.yml b/activerecord/test/fixtures/authors.yml
new file mode 100644
index 0000000000..832236a486
--- /dev/null
+++ b/activerecord/test/fixtures/authors.yml
@@ -0,0 +1,15 @@
+david:
+  id: 1
+  name: David
+  author_address_id: 1
+  author_address_extra_id: 2
+  organization_id: No Such Agency
+  owned_essay_id: A Modest Proposal
+
+mary:
+  id: 2
+  name: Mary
+
+bob:
+  id: 3
+  name: Bob
diff --git a/activerecord/test/fixtures/binaries.yml b/activerecord/test/fixtures/binaries.yml
new file mode 100644
index 0000000000..ec8f2facdc
--- /dev/null
+++ b/activerecord/test/fixtures/binaries.yml
@@ -0,0 +1,133 @@
+flowers:
+  id: 1
+  data: !binary |-
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diff --git a/activerecord/test/fixtures/books.yml b/activerecord/test/fixtures/books.yml
new file mode 100644
index 0000000000..abe56752c6
--- /dev/null
+++ b/activerecord/test/fixtures/books.yml
@@ -0,0 +1,11 @@
+awdr:
+  author_id: 1
+  id: 1
+  name: "Agile Web Development with Rails"
+  format: "paperback"
+
+rfr:
+  author_id: 1
+  id: 2
+  name: "Ruby for Rails"
+  format: "ebook"
diff --git a/activerecord/test/fixtures/cars.yml b/activerecord/test/fixtures/cars.yml
new file mode 100644
index 0000000000..b4c748aaa7
--- /dev/null
+++ b/activerecord/test/fixtures/cars.yml
@@ -0,0 +1,9 @@
+honda:
+  id: 1
+  name: honda
+  engines_count: 0
+
+zyke:
+  id: 2
+  name: zyke
+  engines_count: 0
diff --git a/activerecord/test/fixtures/categories.yml b/activerecord/test/fixtures/categories.yml
new file mode 100644
index 0000000000..3e75e733a6
--- /dev/null
+++ b/activerecord/test/fixtures/categories.yml
@@ -0,0 +1,19 @@
+general:
+  id: 1
+  name: General
+  type: Category
+
+technology:
+  id: 2
+  name: Technology
+  type: Category
+
+sti_test:
+  id: 3
+  name: Special category
+  type: SpecialCategory
+
+cooking:
+  id: 4
+  name: Cooking
+  type: Category
diff --git a/activerecord/test/fixtures/categories/special_categories.yml b/activerecord/test/fixtures/categories/special_categories.yml
new file mode 100644
index 0000000000..517fc8f7ad
--- /dev/null
+++ b/activerecord/test/fixtures/categories/special_categories.yml
@@ -0,0 +1,9 @@
+sub_special_1:
+  id: 100
+  name: A special category in a subdir file
+  type: SpecialCategory
+
+sub_special_2:
+  id: 101
+  name: Another special category
+  type: SpecialCategory
diff --git a/activerecord/test/fixtures/categories/subsubdir/arbitrary_filename.yml b/activerecord/test/fixtures/categories/subsubdir/arbitrary_filename.yml
new file mode 100644
index 0000000000..389a04a5aa
--- /dev/null
+++ b/activerecord/test/fixtures/categories/subsubdir/arbitrary_filename.yml
@@ -0,0 +1,4 @@
+sub_special_3:
+  id: 102
+  name: A special category in an arbitrarily named subsubdir file
+  type: SpecialCategory
diff --git a/activerecord/test/fixtures/categories_ordered.yml b/activerecord/test/fixtures/categories_ordered.yml
new file mode 100644
index 0000000000..294a6368d6
--- /dev/null
+++ b/activerecord/test/fixtures/categories_ordered.yml
@@ -0,0 +1,7 @@
+--- !omap
+<% 100.times do |i| %>
+- fixture_no_<%= i %>:
+    id: <%= i %>
+    name: <%= "Category #{i}" %>
+    type: Category
+<% end %>
diff --git a/activerecord/test/fixtures/categories_posts.yml b/activerecord/test/fixtures/categories_posts.yml
new file mode 100644
index 0000000000..c6f0d885f5
--- /dev/null
+++ b/activerecord/test/fixtures/categories_posts.yml
@@ -0,0 +1,31 @@
+general_welcome:
+  category_id: 1
+  post_id: 1
+
+technology_welcome:
+  category_id: 2
+  post_id: 1
+
+general_thinking:
+  category_id: 1
+  post_id: 2
+
+general_sti_habtm:
+  category_id: 1
+  post_id: 6
+
+sti_test_sti_habtm:
+  category_id: 3
+  post_id: 6
+
+general_hello:
+  category_id: 1
+  post_id: 4
+
+general_misc_by_bob:
+  category_id: 1
+  post_id: 8
+
+cooking_misc_by_bob:
+  category_id: 4
+  post_id: 8
diff --git a/activerecord/test/fixtures/categorizations.yml b/activerecord/test/fixtures/categorizations.yml
new file mode 100644
index 0000000000..62e5bd111a
--- /dev/null
+++ b/activerecord/test/fixtures/categorizations.yml
@@ -0,0 +1,23 @@
+david_welcome_general:
+  id: 1
+  author_id: 1
+  post_id: 1
+  category_id: 1
+
+mary_thinking_sti:
+  id: 2
+  author_id: 2
+  post_id: 2
+  category_id: 3
+
+mary_thinking_general:
+  id: 3
+  author_id: 2
+  post_id: 2
+  category_id: 1
+
+bob_misc_by_bob_technology:
+  id: 4
+  author_id: 3
+  post_id: 8
+  category_id: 2
diff --git a/activerecord/test/fixtures/clubs.yml b/activerecord/test/fixtures/clubs.yml
new file mode 100644
index 0000000000..82e439e8e5
--- /dev/null
+++ b/activerecord/test/fixtures/clubs.yml
@@ -0,0 +1,8 @@
+boring_club:
+  name: Banana appreciation society
+  category_id: 1
+moustache_club:
+  name: Moustache and Eyebrow Fancier Club
+crazy_club:
+  name: Skull and bones
+  category_id: 2
diff --git a/activerecord/test/fixtures/collections.yml b/activerecord/test/fixtures/collections.yml
new file mode 100644
index 0000000000..ad0fd26554
--- /dev/null
+++ b/activerecord/test/fixtures/collections.yml
@@ -0,0 +1,3 @@
+collection_1:
+  id: 1
+  name: Collection
diff --git a/activerecord/test/fixtures/colleges.yml b/activerecord/test/fixtures/colleges.yml
new file mode 100644
index 0000000000..27591e0c2c
--- /dev/null
+++ b/activerecord/test/fixtures/colleges.yml
@@ -0,0 +1,3 @@
+FIU:
+  id: 1
+  name: Florida International University
diff --git a/activerecord/test/fixtures/comments.yml b/activerecord/test/fixtures/comments.yml
new file mode 100644
index 0000000000..ddbb823c49
--- /dev/null
+++ b/activerecord/test/fixtures/comments.yml
@@ -0,0 +1,65 @@
+greetings:
+  id: 1
+  post_id: 1
+  body: Thank you for the welcome
+  type: Comment
+
+more_greetings:
+  id: 2
+  post_id: 1
+  body: Thank you again for the welcome
+  type: Comment
+
+does_it_hurt:
+  id: 3
+  post_id: 2
+  body: Don't think too hard
+  type: SpecialComment
+
+eager_sti_on_associations_vs_comment:
+  id: 5
+  post_id: 4
+  body: Very Special type
+  type: VerySpecialComment
+
+eager_sti_on_associations_s_comment1:
+  id: 6
+  post_id: 4
+  body: Special type
+  type: SpecialComment
+
+eager_sti_on_associations_s_comment2:
+  id: 7
+  post_id: 4
+  body: Special type 2
+  type: SpecialComment
+
+eager_sti_on_associations_comment:
+  id: 8
+  post_id: 4
+  body: Normal type
+  type: Comment
+
+check_eager_sti_on_associations:
+  id: 9
+  post_id: 5
+  body: Normal type
+  type: Comment
+
+check_eager_sti_on_associations2:
+  id: 10
+  post_id: 5
+  body: Special Type
+  type: SpecialComment
+
+eager_other_comment1:
+  id: 11
+  post_id: 7
+  body: go crazy
+  type: SpecialComment
+
+sub_special_comment:
+  id: 12
+  post_id: 4
+  body: Sub special comment
+  type: SubSpecialComment
diff --git a/activerecord/test/fixtures/companies.yml b/activerecord/test/fixtures/companies.yml
new file mode 100644
index 0000000000..ab9d5378ad
--- /dev/null
+++ b/activerecord/test/fixtures/companies.yml
@@ -0,0 +1,67 @@
+first_client:
+  id: 2
+  type: Client
+  firm_id: 1
+  client_of: 2
+  name: Summit
+  firm_name: 37signals
+
+first_firm:
+  id: 1
+  type: Firm
+  name: 37signals
+  firm_id: 1
+
+second_client:
+  id: 3
+  type: Client
+  firm_id: 1
+  client_of: 1
+  name: Microsoft
+
+another_firm:
+  id: 4
+  type: Firm
+  name: Flamboyant Software
+
+another_client:
+  id: 5
+  type: Client
+  firm_id: 4
+  client_of: 4
+  name: Ex Nihilo
+
+a_third_client:
+  id: 10
+  type: Client
+  firm_id: 4
+  client_of: 4
+  name: Ex Nihilo Part Deux
+
+rails_core:
+  id: 6
+  name: RailsCore
+  type: DependentFirm
+
+leetsoft:
+  id: 7
+  name: Leetsoft
+  client_of: 6
+
+jadedpixel:
+  id: 8
+  name: Jadedpixel
+  client_of: 6
+
+odegy:
+  id: 9
+  name: Odegy
+  type: ExclusivelyDependentFirm
+
+another_first_firm_client:
+  id: 11
+  type: Client
+  firm_id: 1
+  client_of: 1
+  name: Apex
+  firm_name: 37signals
diff --git a/activerecord/test/fixtures/computers.yml b/activerecord/test/fixtures/computers.yml
new file mode 100644
index 0000000000..7281a4d768
--- /dev/null
+++ b/activerecord/test/fixtures/computers.yml
@@ -0,0 +1,5 @@
+workstation:
+  id: 1
+  system: 'Linux'
+  developer: 1
+  extendedWarranty: 1
diff --git a/activerecord/test/fixtures/courses.yml b/activerecord/test/fixtures/courses.yml
new file mode 100644
index 0000000000..de3a4a97e5
--- /dev/null
+++ b/activerecord/test/fixtures/courses.yml
@@ -0,0 +1,8 @@
+ruby:
+  id: 1
+  name: Ruby Development
+  college: FIU
+
+java:
+  id: 2
+  name: Java Development
diff --git a/activerecord/test/fixtures/customers.yml b/activerecord/test/fixtures/customers.yml
new file mode 100644
index 0000000000..0399ff83b9
--- /dev/null
+++ b/activerecord/test/fixtures/customers.yml
@@ -0,0 +1,26 @@
+david:
+  id: 1
+  name: David
+  balance: 50
+  address_street: Funny Street
+  address_city: Scary Town
+  address_country: Loony Land
+  gps_location: 35.544623640962634x-105.9309951055148
+
+zaphod:
+  id: 2
+  name: Zaphod
+  balance: 62
+  address_street: Avenue Road
+  address_city: Hamlet Town
+  address_country: Nation Land
+  gps_location: NULL
+
+barney:
+  id: 3
+  name: Barney Gumble
+  balance: 1
+  address_street: Quiet Road
+  address_city: Peaceful Town
+  address_country: Tranquil Land
+  gps_location: NULL
\ No newline at end of file
diff --git a/activerecord/test/fixtures/dashboards.yml b/activerecord/test/fixtures/dashboards.yml
new file mode 100644
index 0000000000..a4c7e0d309
--- /dev/null
+++ b/activerecord/test/fixtures/dashboards.yml
@@ -0,0 +1,6 @@
+cool_first:
+  dashboard_id: d1
+  name: my_dashboard
+second:
+  dashboard_id: d2
+  name: second
diff --git a/activerecord/test/fixtures/developers.yml b/activerecord/test/fixtures/developers.yml
new file mode 100644
index 0000000000..3656564f63
--- /dev/null
+++ b/activerecord/test/fixtures/developers.yml
@@ -0,0 +1,21 @@
+david:
+  id: 1
+  name: David
+  salary: 80000
+
+jamis:
+  id: 2
+  name: Jamis
+  salary: 150000
+
+<% (3..10).each do |digit| %>
+dev_<%= digit %>:
+  id: <%= digit %>
+  name: fixture_<%= digit %>
+  salary: 100000
+<% end %>
+
+poor_jamis:
+  id: 11
+  name: Jamis
+  salary: 9000
\ No newline at end of file
diff --git a/activerecord/test/fixtures/developers_projects.yml b/activerecord/test/fixtures/developers_projects.yml
new file mode 100644
index 0000000000..572958707f
--- /dev/null
+++ b/activerecord/test/fixtures/developers_projects.yml
@@ -0,0 +1,17 @@
+david_action_controller:
+  developer_id: 1
+  project_id: 2
+  joined_on: 2004-10-10
+
+david_active_record:
+  developer_id: 1
+  project_id: 1
+  joined_on: 2004-10-10
+
+jamis_active_record:
+  developer_id: 2
+  project_id: 1
+
+poor_jamis_active_record:
+  developer_id: 11
+  project_id: 1
\ No newline at end of file
diff --git a/activerecord/test/fixtures/dog_lovers.yml b/activerecord/test/fixtures/dog_lovers.yml
new file mode 100644
index 0000000000..3f4c6c9e4c
--- /dev/null
+++ b/activerecord/test/fixtures/dog_lovers.yml
@@ -0,0 +1,7 @@
+david:
+  id: 1
+  bred_dogs_count: 0
+  trained_dogs_count: 1
+joanna:
+  id: 2
+  dogs_count: 1
diff --git a/activerecord/test/fixtures/dogs.yml b/activerecord/test/fixtures/dogs.yml
new file mode 100644
index 0000000000..b5eb2c7b74
--- /dev/null
+++ b/activerecord/test/fixtures/dogs.yml
@@ -0,0 +1,4 @@
+sophie:
+  id: 1
+  trainer_id: 1
+  dog_lover_id: 2
diff --git a/activerecord/test/fixtures/edges.yml b/activerecord/test/fixtures/edges.yml
new file mode 100644
index 0000000000..b804f7b6a6
--- /dev/null
+++ b/activerecord/test/fixtures/edges.yml
@@ -0,0 +1,5 @@
+<% (1..4).each do |id| %>
+edge_<%= id %>:
+  source_id: <%= id %>
+  sink_id: <%= id + 1 %>
+<% end %>
diff --git a/activerecord/test/fixtures/entrants.yml b/activerecord/test/fixtures/entrants.yml
new file mode 100644
index 0000000000..86f0108e52
--- /dev/null
+++ b/activerecord/test/fixtures/entrants.yml
@@ -0,0 +1,14 @@
+first:
+  id: 1
+  course_id: 1
+  name: Ruby Developer
+
+second:
+  id: 2
+  course_id: 1
+  name: Ruby Guru
+
+third:
+  id: 3
+  course_id: 2
+  name: Java Lover
diff --git a/activerecord/test/fixtures/essays.yml b/activerecord/test/fixtures/essays.yml
new file mode 100644
index 0000000000..9d15d82359
--- /dev/null
+++ b/activerecord/test/fixtures/essays.yml
@@ -0,0 +1,6 @@
+david_modest_proposal:
+  name: A Modest Proposal
+  writer_type: Author
+  writer_id: David
+  category_id: General
+  author_id: David
diff --git a/activerecord/test/fixtures/faces.yml b/activerecord/test/fixtures/faces.yml
new file mode 100644
index 0000000000..c8e4a34484
--- /dev/null
+++ b/activerecord/test/fixtures/faces.yml
@@ -0,0 +1,11 @@
+trusting:
+  description: trusting
+  man: gordon
+
+weather_beaten:
+  description: weather beaten
+  man: steve
+
+confused:
+  description: confused
+  polymorphic_man: gordon (Man)
diff --git a/activerecord/test/fixtures/fk_test_has_fk.yml b/activerecord/test/fixtures/fk_test_has_fk.yml
new file mode 100644
index 0000000000..67d914e130
--- /dev/null
+++ b/activerecord/test/fixtures/fk_test_has_fk.yml
@@ -0,0 +1,3 @@
+first:
+  id: 1
+  fk_id: 1
diff --git a/activerecord/test/fixtures/fk_test_has_pk.yml b/activerecord/test/fixtures/fk_test_has_pk.yml
new file mode 100644
index 0000000000..73882bac41
--- /dev/null
+++ b/activerecord/test/fixtures/fk_test_has_pk.yml
@@ -0,0 +1,2 @@
+first:
+  pk_id: 1
\ No newline at end of file
diff --git a/activerecord/test/fixtures/friendships.yml b/activerecord/test/fixtures/friendships.yml
new file mode 100644
index 0000000000..ae0abe0162
--- /dev/null
+++ b/activerecord/test/fixtures/friendships.yml
@@ -0,0 +1,4 @@
+Connection 1:
+  id: 1
+  friend_id: 1
+  follower_id: 2
diff --git a/activerecord/test/fixtures/funny_jokes.yml b/activerecord/test/fixtures/funny_jokes.yml
new file mode 100644
index 0000000000..d47c4a6a10
--- /dev/null
+++ b/activerecord/test/fixtures/funny_jokes.yml
@@ -0,0 +1,10 @@
+a_joke:
+  id: 1
+  name: Knock knock
+
+another_joke:
+  id: 2
+  name: |
+       The \n Aristocrats
+       Ate the candy
+
diff --git a/activerecord/test/fixtures/interests.yml b/activerecord/test/fixtures/interests.yml
new file mode 100644
index 0000000000..9200a19d5a
--- /dev/null
+++ b/activerecord/test/fixtures/interests.yml
@@ -0,0 +1,33 @@
+trainspotting:
+  topic: Trainspotting
+  zine: staying_in
+  man: gordon
+
+birdwatching:
+  topic: Birdwatching
+  zine: staying_in
+  man: gordon
+
+stamp_collecting:
+  topic: Stamp Collecting
+  zine: staying_in
+  man: gordon
+
+hunting:
+  topic: Hunting
+  zine: going_out
+  man: steve
+
+woodsmanship:
+  topic: Woodsmanship
+  zine: going_out
+  man: steve
+
+survival:
+  topic: Survival
+  zine: going_out
+  man: steve
+
+llama_wrangling:
+  topic: Llama Wrangling
+  polymorphic_man: gordon (Man)
diff --git a/activerecord/test/fixtures/items.yml b/activerecord/test/fixtures/items.yml
new file mode 100644
index 0000000000..94e3821445
--- /dev/null
+++ b/activerecord/test/fixtures/items.yml
@@ -0,0 +1,3 @@
+dvd:
+  id: 1
+  name: Godfather
diff --git a/activerecord/test/fixtures/jobs.yml b/activerecord/test/fixtures/jobs.yml
new file mode 100644
index 0000000000..f5775d27d3
--- /dev/null
+++ b/activerecord/test/fixtures/jobs.yml
@@ -0,0 +1,7 @@
+unicyclist:
+  id: 1
+  ideal_reference_id: 2
+clown:
+  id: 2
+magician:
+  id: 3
diff --git a/activerecord/test/fixtures/legacy_things.yml b/activerecord/test/fixtures/legacy_things.yml
new file mode 100644
index 0000000000..a6d42aab5d
--- /dev/null
+++ b/activerecord/test/fixtures/legacy_things.yml
@@ -0,0 +1,3 @@
+obtuse:
+  id: 1
+  tps_report_number: 500
diff --git a/activerecord/test/fixtures/mateys.yml b/activerecord/test/fixtures/mateys.yml
new file mode 100644
index 0000000000..3f0405aaf8
--- /dev/null
+++ b/activerecord/test/fixtures/mateys.yml
@@ -0,0 +1,4 @@
+blackbeard_to_redbeard:
+  pirate_id: <%= ActiveRecord::FixtureSet.identify(:blackbeard) %>
+  target_id: <%= ActiveRecord::FixtureSet.identify(:redbeard) %>
+  weight: 10
diff --git a/activerecord/test/fixtures/member_details.yml b/activerecord/test/fixtures/member_details.yml
new file mode 100644
index 0000000000..e1fe695a9b
--- /dev/null
+++ b/activerecord/test/fixtures/member_details.yml
@@ -0,0 +1,8 @@
+groucho:
+  id: 1
+  member_id: 1
+  organization: nsa
+some_other_guy:
+  id: 2
+  member_id: 2
+  organization: nsa
diff --git a/activerecord/test/fixtures/member_types.yml b/activerecord/test/fixtures/member_types.yml
new file mode 100644
index 0000000000..797a57430c
--- /dev/null
+++ b/activerecord/test/fixtures/member_types.yml
@@ -0,0 +1,6 @@
+founding:
+  id: 1
+  name: Founding
+provisional:
+  id: 2
+  name: Provisional
diff --git a/activerecord/test/fixtures/members.yml b/activerecord/test/fixtures/members.yml
new file mode 100644
index 0000000000..f3bbf0dac6
--- /dev/null
+++ b/activerecord/test/fixtures/members.yml
@@ -0,0 +1,11 @@
+groucho:
+  id: 1
+  name: Groucho Marx
+  member_type_id: 1
+some_other_guy:
+  id: 2
+  name: Englebert Humperdink
+  member_type_id: 2
+blarpy_winkup:
+  id: 3
+  name: Blarpy Winkup
diff --git a/activerecord/test/fixtures/memberships.yml b/activerecord/test/fixtures/memberships.yml
new file mode 100644
index 0000000000..a5d52bd438
--- /dev/null
+++ b/activerecord/test/fixtures/memberships.yml
@@ -0,0 +1,34 @@
+membership_of_boring_club:
+  joined_on: <%= 3.weeks.ago.to_s(:db) %>
+  club: boring_club
+  member_id: 1
+  favourite: false
+  type: CurrentMembership
+
+membership_of_favourite_club:
+  joined_on: <%= 3.weeks.ago.to_s(:db) %>
+  club: moustache_club
+  member_id: 1
+  favourite: true
+  type: Membership
+
+other_guys_membership:
+  joined_on: <%= 4.weeks.ago.to_s(:db) %>
+  club: boring_club
+  member_id: 2
+  favourite: false
+  type: CurrentMembership
+
+blarpy_winkup_crazy_club:
+  joined_on: <%= 4.weeks.ago.to_s(:db) %>
+  club: crazy_club
+  member_id: 3
+  favourite: false
+  type: CurrentMembership
+
+selected_membership_of_boring_club:
+  joined_on: <%= 3.weeks.ago.to_s(:db) %>
+  club: boring_club
+  member_id: 1
+  favourite: false
+  type: SelectedMembership
diff --git a/activerecord/test/fixtures/men.yml b/activerecord/test/fixtures/men.yml
new file mode 100644
index 0000000000..c67429f925
--- /dev/null
+++ b/activerecord/test/fixtures/men.yml
@@ -0,0 +1,5 @@
+gordon:
+  name: Gordon
+
+steve:
+  name: Steve
diff --git a/activerecord/test/fixtures/minimalistics.yml b/activerecord/test/fixtures/minimalistics.yml
new file mode 100644
index 0000000000..c3ec546209
--- /dev/null
+++ b/activerecord/test/fixtures/minimalistics.yml
@@ -0,0 +1,2 @@
+first:
+  id: 1
diff --git a/activerecord/test/fixtures/minivans.yml b/activerecord/test/fixtures/minivans.yml
new file mode 100644
index 0000000000..f1224a4c1a
--- /dev/null
+++ b/activerecord/test/fixtures/minivans.yml
@@ -0,0 +1,5 @@
+cool_first:
+  minivan_id: m1
+  name: my_minivan
+  speedometer_id: s1
+  color: blue
diff --git a/activerecord/test/fixtures/mixed_case_monkeys.yml b/activerecord/test/fixtures/mixed_case_monkeys.yml
new file mode 100644
index 0000000000..eecd448f4b
--- /dev/null
+++ b/activerecord/test/fixtures/mixed_case_monkeys.yml
@@ -0,0 +1,6 @@
+first:
+  monkeyID: 1
+  fleaCount: 42
+second:
+  monkeyID: 2
+  fleaCount: 43
diff --git a/activerecord/test/fixtures/mixins.yml b/activerecord/test/fixtures/mixins.yml
new file mode 100644
index 0000000000..f0009cc5f0
--- /dev/null
+++ b/activerecord/test/fixtures/mixins.yml
@@ -0,0 +1,29 @@
+# Nested set mixins
+
+<% (1..10).each do |counter| %>
+set_<%= counter %>:
+  id: <%= counter+3000 %>
+<% end %>
+
+# Big old set
+<%
+[[4001, 0, 1, 20],
+  [4002, 4001, 2, 7],
+  [4003, 4002, 3, 4],
+  [4004, 4002, 5, 6],
+  [4005, 4001, 14, 13],
+  [4006, 4005, 9, 10],
+  [4007, 4005, 11, 12],
+  [4008, 4001, 8, 19],
+  [4009, 4008, 15, 16],
+  [4010, 4008, 17, 18]].each do |set| %>
+tree_<%= set[0] %>:
+  id: <%= set[0]%>
+  parent_id: <%= set[1]%>
+  type: NestedSetWithStringScope
+  lft: <%= set[2]%>
+  rgt: <%= set[3]%>
+  root_id: 42
+
+<% end %>
+
diff --git a/activerecord/test/fixtures/movies.yml b/activerecord/test/fixtures/movies.yml
new file mode 100644
index 0000000000..2e9154fda8
--- /dev/null
+++ b/activerecord/test/fixtures/movies.yml
@@ -0,0 +1,7 @@
+first:
+  movieid: 1
+  name: Terminator
+
+second:
+  movieid: 2
+  name: Gladiator
diff --git a/activerecord/test/fixtures/naked/csv/accounts.csv b/activerecord/test/fixtures/naked/csv/accounts.csv
new file mode 100644
index 0000000000..8b13789179
--- /dev/null
+++ b/activerecord/test/fixtures/naked/csv/accounts.csv
@@ -0,0 +1 @@
+
diff --git a/activerecord/test/fixtures/naked/yml/accounts.yml b/activerecord/test/fixtures/naked/yml/accounts.yml
new file mode 100644
index 0000000000..8b13789179
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/accounts.yml
@@ -0,0 +1 @@
+
diff --git a/activerecord/test/fixtures/naked/yml/companies.yml b/activerecord/test/fixtures/naked/yml/companies.yml
new file mode 100644
index 0000000000..2c151c203b
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/companies.yml
@@ -0,0 +1 @@
+# i wonder what will happen here
diff --git a/activerecord/test/fixtures/naked/yml/courses.yml b/activerecord/test/fixtures/naked/yml/courses.yml
new file mode 100644
index 0000000000..19f0805d8d
--- /dev/null
+++ b/activerecord/test/fixtures/naked/yml/courses.yml
@@ -0,0 +1 @@
+qwerty
diff --git a/activerecord/test/fixtures/organizations.yml b/activerecord/test/fixtures/organizations.yml
new file mode 100644
index 0000000000..25295bff87
--- /dev/null
+++ b/activerecord/test/fixtures/organizations.yml
@@ -0,0 +1,5 @@
+nsa:
+  name: No Such Agency
+discordians:
+  name: Discordians
+
diff --git a/activerecord/test/fixtures/other_topics.yml b/activerecord/test/fixtures/other_topics.yml
new file mode 100644
index 0000000000..93f48aedc4
--- /dev/null
+++ b/activerecord/test/fixtures/other_topics.yml
@@ -0,0 +1,42 @@
+first:
+  id: 1
+  title: The First Topic
+  author_name: David
+  author_email_address: david@loudthinking.com
+  written_on: 2003-07-16t15:28:11.2233+01:00
+  last_read: 2004-04-15
+  bonus_time: 2005-01-30t15:28:00.00+01:00
+  content: Have a nice day
+  approved: false
+  replies_count: 1
+
+second:
+  id: 2
+  title: The Second Topic of the day
+  author_name: Mary
+  written_on: 2004-07-15t15:28:00.0099+01:00
+  content: Have a nice day
+  approved: true
+  replies_count: 0
+  parent_id: 1
+  type: Reply
+
+third:
+  id: 3
+  title: The Third Topic of the day
+  author_name: Carl
+  written_on: 2005-07-15t15:28:00.0099+01:00
+  content: I'm a troll
+  approved: true
+  replies_count: 1
+
+fourth:
+  id: 4
+  title: The Fourth Topic of the day
+  author_name: Carl
+  written_on: 2006-07-15t15:28:00.0099+01:00
+  content: Why not?
+  approved: true
+  type: Reply
+  parent_id: 3
+
diff --git a/activerecord/test/fixtures/owners.yml b/activerecord/test/fixtures/owners.yml
new file mode 100644
index 0000000000..3b7b29bb34
--- /dev/null
+++ b/activerecord/test/fixtures/owners.yml
@@ -0,0 +1,9 @@
+blackbeard:
+  owner_id: 1
+  name: blackbeard
+  essay_id: A Modest Proposal
+  happy_at: '2150-10-10 16:00:00'
+
+ashley:
+  owner_id: 2
+  name: ashley
diff --git a/activerecord/test/fixtures/parrots.yml b/activerecord/test/fixtures/parrots.yml
new file mode 100644
index 0000000000..8425ef98e0
--- /dev/null
+++ b/activerecord/test/fixtures/parrots.yml
@@ -0,0 +1,27 @@
+george:
+  name: "Curious George"
+  treasures: diamond, sapphire
+  parrot_sti_class: LiveParrot
+
+louis:
+  name: "King Louis"
+  treasures: [diamond, sapphire]
+  parrot_sti_class: LiveParrot
+
+frederick:
+  name: $LABEL
+  parrot_sti_class: LiveParrot
+
+polly:
+  id: 4
+  name: $LABEL
+  killer: blackbeard
+  treasures: sapphire, ruby
+  parrot_sti_class: DeadParrot
+
+DEFAULTS: &DEFAULTS
+  treasures: sapphire, ruby
+  parrot_sti_class: LiveParrot
+
+davey:
+  *DEFAULTS
diff --git a/activerecord/test/fixtures/parrots_pirates.yml b/activerecord/test/fixtures/parrots_pirates.yml
new file mode 100644
index 0000000000..e1a301b91a
--- /dev/null
+++ b/activerecord/test/fixtures/parrots_pirates.yml
@@ -0,0 +1,7 @@
+george_blackbeard:
+  parrot_id: <%= ActiveRecord::FixtureSet.identify(:george) %>
+  pirate_id: <%= ActiveRecord::FixtureSet.identify(:blackbeard) %>
+
+louis_blackbeard:
+  parrot_id: <%= ActiveRecord::FixtureSet.identify(:louis) %>
+  pirate_id: <%= ActiveRecord::FixtureSet.identify(:blackbeard) %>
diff --git a/activerecord/test/fixtures/people.yml b/activerecord/test/fixtures/people.yml
new file mode 100644
index 0000000000..0ec05e8d56
--- /dev/null
+++ b/activerecord/test/fixtures/people.yml
@@ -0,0 +1,24 @@
+michael:
+  id: 1
+  first_name: Michael
+  primary_contact_id: 2
+  number1_fan_id: 3
+  gender: M
+  followers_count: 1
+  friends_too_count: 1
+david:
+  id: 2
+  first_name: David
+  primary_contact_id: 3
+  number1_fan_id: 1
+  gender: M
+  followers_count: 1
+  friends_too_count: 1
+susan:
+  id: 3
+  first_name: Susan
+  primary_contact_id: 2
+  number1_fan_id: 1
+  gender: F
+  followers_count: 1
+  friends_too_count: 1
diff --git a/activerecord/test/fixtures/peoples_treasures.yml b/activerecord/test/fixtures/peoples_treasures.yml
new file mode 100644
index 0000000000..46abe50e6c
--- /dev/null
+++ b/activerecord/test/fixtures/peoples_treasures.yml
@@ -0,0 +1,3 @@
+michael_diamond:
+  rich_person_id: <%= ActiveRecord::FixtureSet.identify(:michael) %>
+  treasure_id: <%= ActiveRecord::FixtureSet.identify(:diamond) %>
diff --git a/activerecord/test/fixtures/pets.yml b/activerecord/test/fixtures/pets.yml
new file mode 100644
index 0000000000..2ec4f53e6d
--- /dev/null
+++ b/activerecord/test/fixtures/pets.yml
@@ -0,0 +1,19 @@
+parrot:
+  pet_id: 1
+  name: parrot
+  owner_id: 1
+
+chew:
+  pet_id: 2
+  name: chew
+  owner_id: 2
+
+mochi:
+  pet_id: 3
+  name: mochi
+  owner_id: 2
+
+bulbul:
+  pet_id: 4
+  name: bulbul
+  owner_id: 1
diff --git a/activerecord/test/fixtures/pirates.yml b/activerecord/test/fixtures/pirates.yml
new file mode 100644
index 0000000000..1bb3bf0051
--- /dev/null
+++ b/activerecord/test/fixtures/pirates.yml
@@ -0,0 +1,12 @@
+blackbeard:
+  catchphrase: "Yar."
+  parrot: george
+
+redbeard:
+  catchphrase: "Avast!"
+  parrot: louis
+  created_on: "<%= 2.weeks.ago.to_s(:db) %>"
+  updated_on: "<%= 2.weeks.ago.to_s(:db) %>"
+
+mark:
+  catchphrase: "X $LABELs the spot!"
diff --git a/activerecord/test/fixtures/posts.yml b/activerecord/test/fixtures/posts.yml
new file mode 100644
index 0000000000..86d46f753a
--- /dev/null
+++ b/activerecord/test/fixtures/posts.yml
@@ -0,0 +1,80 @@
+welcome:
+  id: 1
+  author_id: 1
+  title: Welcome to the weblog
+  body: Such a lovely day
+  comments_count: 2
+  tags_count: 1
+  type: Post
+
+thinking:
+  id: 2
+  author_id: 1
+  title: So I was thinking
+  body: Like I hopefully always am
+  comments_count: 1
+  tags_count: 1
+  type: SpecialPost
+
+authorless:
+  id: 3
+  author_id: 0
+  title: I don't have any comments
+  body: I just don't want to
+  type: Post
+
+sti_comments:
+  id: 4
+  author_id: 1
+  title: sti comments
+  body: hello
+  type: Post
+
+sti_post_and_comments:
+  id: 5
+  author_id: 1
+  title: sti me
+  body: hello
+  type: StiPost
+
+sti_habtm:
+  id: 6
+  author_id: 1
+  title: habtm sti test
+  body: hello
+  type: Post
+
+eager_other:
+  id: 7
+  author_id: 2
+  title: eager loading with OR'd conditions
+  body: hello
+  type: Post
+
+misc_by_bob:
+  id: 8
+  author_id: 3
+  title: misc post by bob
+  body: hello
+  type: Post
+
+misc_by_mary:
+  id: 9
+  author_id: 2
+  title: misc post by mary
+  body: hello
+  type: Post
+
+other_by_bob:
+  id: 10
+  author_id: 3
+  title: other post by bob
+  body: hello
+  type: Post
+
+other_by_mary:
+  id: 11
+  author_id: 2
+  title: other post by mary
+  body: hello
+  type: Post
diff --git a/activerecord/test/fixtures/price_estimates.yml b/activerecord/test/fixtures/price_estimates.yml
new file mode 100644
index 0000000000..1149ab17a2
--- /dev/null
+++ b/activerecord/test/fixtures/price_estimates.yml
@@ -0,0 +1,7 @@
+saphire_1:
+  price: 10
+  estimate_of: sapphire (Treasure)
+
+sapphire_2:
+  price: 20
+  estimate_of: sapphire (Treasure)
diff --git a/activerecord/test/fixtures/products.yml b/activerecord/test/fixtures/products.yml
new file mode 100644
index 0000000000..8a197fb038
--- /dev/null
+++ b/activerecord/test/fixtures/products.yml
@@ -0,0 +1,4 @@
+product_1:
+  id: 1
+  collection_id: 1
+  name: Product
diff --git a/activerecord/test/fixtures/projects.yml b/activerecord/test/fixtures/projects.yml
new file mode 100644
index 0000000000..02800c7824
--- /dev/null
+++ b/activerecord/test/fixtures/projects.yml
@@ -0,0 +1,7 @@
+action_controller:
+  id: 2
+  name: Active Controller
+
+active_record:
+  id: 1
+  name: Active Record
diff --git a/activerecord/test/fixtures/randomly_named_a9.yml b/activerecord/test/fixtures/randomly_named_a9.yml
new file mode 100644
index 0000000000..bc51c83112
--- /dev/null
+++ b/activerecord/test/fixtures/randomly_named_a9.yml
@@ -0,0 +1,7 @@
+first_instance:

+  some_attribute: AAA

+  another_attribute: 000

+

+second_instance:

+  some_attribute: BBB

+  another_attribute: 999

diff --git a/activerecord/test/fixtures/ratings.yml b/activerecord/test/fixtures/ratings.yml
new file mode 100644
index 0000000000..34e208efa3
--- /dev/null
+++ b/activerecord/test/fixtures/ratings.yml
@@ -0,0 +1,14 @@
+normal_comment_rating:
+  id: 1
+  comment_id: 8
+  value: 1
+
+special_comment_rating:
+  id: 2
+  comment_id: 6
+  value: 1
+
+sub_special_comment_rating:
+  id: 3
+  comment_id: 12
+  value: 1
diff --git a/activerecord/test/fixtures/readers.yml b/activerecord/test/fixtures/readers.yml
new file mode 100644
index 0000000000..14b883f041
--- /dev/null
+++ b/activerecord/test/fixtures/readers.yml
@@ -0,0 +1,11 @@
+michael_welcome:
+  id: 1
+  post_id: 1
+  person_id: 1
+  first_post_id: 2
+
+michael_authorless:
+  id: 2
+  post_id: 3
+  person_id: 1
+  first_post_id: 3
diff --git a/activerecord/test/fixtures/references.yml b/activerecord/test/fixtures/references.yml
new file mode 100644
index 0000000000..8e3953e916
--- /dev/null
+++ b/activerecord/test/fixtures/references.yml
@@ -0,0 +1,17 @@
+michael_magician:
+  id: 1
+  person_id: 1
+  job_id: 3
+  favourite: false
+
+michael_unicyclist:
+  id: 2
+  person_id: 1
+  job_id: 1
+  favourite: true
+
+david_unicyclist:
+  id: 3
+  person_id: 2
+  job_id: 1
+  favourite: false
diff --git a/activerecord/test/fixtures/reserved_words/distinct.yml b/activerecord/test/fixtures/reserved_words/distinct.yml
new file mode 100644
index 0000000000..0988f89ca6
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/distinct.yml
@@ -0,0 +1,5 @@
+distinct1:
+  id: 1
+
+distinct2:
+  id: 2
diff --git a/activerecord/test/fixtures/reserved_words/distinct_select.yml b/activerecord/test/fixtures/reserved_words/distinct_select.yml
new file mode 100644
index 0000000000..d96779ade4
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/distinct_select.yml
@@ -0,0 +1,11 @@
+distinct_select1:
+  distinct_id: 1
+  select_id: 1
+
+distinct_select2:
+  distinct_id: 1
+  select_id: 2
+
+distinct_select3:
+  distinct_id: 2
+  select_id: 3
diff --git a/activerecord/test/fixtures/reserved_words/group.yml b/activerecord/test/fixtures/reserved_words/group.yml
new file mode 100644
index 0000000000..39abea7abb
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/group.yml
@@ -0,0 +1,14 @@
+group1:
+  id: 1
+  select_id: 1
+  order: x
+
+group2:
+  id: 2
+  select_id: 2
+  order: y
+
+group3:
+  id: 3
+  select_id: 2
+  order: z
diff --git a/activerecord/test/fixtures/reserved_words/select.yml b/activerecord/test/fixtures/reserved_words/select.yml
new file mode 100644
index 0000000000..a4c35a2b63
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/select.yml
@@ -0,0 +1,8 @@
+select1:
+  id: 1
+
+select2:
+  id: 2
+
+select3:
+  id: 3
diff --git a/activerecord/test/fixtures/reserved_words/values.yml b/activerecord/test/fixtures/reserved_words/values.yml
new file mode 100644
index 0000000000..7d109609ab
--- /dev/null
+++ b/activerecord/test/fixtures/reserved_words/values.yml
@@ -0,0 +1,7 @@
+values1:
+  id: 1
+  group_id: 2
+
+values2:
+  id: 2
+  group_id: 1
diff --git a/activerecord/test/fixtures/ships.yml b/activerecord/test/fixtures/ships.yml
new file mode 100644
index 0000000000..df914262b3
--- /dev/null
+++ b/activerecord/test/fixtures/ships.yml
@@ -0,0 +1,6 @@
+black_pearl:
+  name: "Black Pearl"
+  pirate: blackbeard
+interceptor:
+  id: 2
+  name: "Interceptor"
diff --git a/activerecord/test/fixtures/speedometers.yml b/activerecord/test/fixtures/speedometers.yml
new file mode 100644
index 0000000000..e12398f0c4
--- /dev/null
+++ b/activerecord/test/fixtures/speedometers.yml
@@ -0,0 +1,8 @@
+cool_first:
+  speedometer_id: s1
+  name: my_speedometer
+  dashboard_id: d1
+second:
+  speedometer_id: s2
+  name: second
+  dashboard_id: d2
diff --git a/activerecord/test/fixtures/sponsors.yml b/activerecord/test/fixtures/sponsors.yml
new file mode 100644
index 0000000000..2da541c539
--- /dev/null
+++ b/activerecord/test/fixtures/sponsors.yml
@@ -0,0 +1,12 @@
+moustache_club_sponsor_for_groucho:
+  sponsor_club: moustache_club
+  sponsorable_id: 1
+  sponsorable_type: Member
+boring_club_sponsor_for_groucho:
+  sponsor_club: boring_club
+  sponsorable_id: 2
+  sponsorable_type: Member
+crazy_club_sponsor_for_groucho:
+  sponsor_club: crazy_club
+  sponsorable_id: 3
+  sponsorable_type: Member
diff --git a/activerecord/test/fixtures/string_key_objects.yml b/activerecord/test/fixtures/string_key_objects.yml
new file mode 100644
index 0000000000..fa1299915b
--- /dev/null
+++ b/activerecord/test/fixtures/string_key_objects.yml
@@ -0,0 +1,7 @@
+first:
+  id: record1
+  name: first record
+
+second:
+  id: record2
+  name: second record
diff --git a/activerecord/test/fixtures/subscribers.yml b/activerecord/test/fixtures/subscribers.yml
new file mode 100644
index 0000000000..c6a8c2fa24
--- /dev/null
+++ b/activerecord/test/fixtures/subscribers.yml
@@ -0,0 +1,11 @@
+first:
+  nick: alterself
+  name: Luke Holden
+
+second:
+  nick: webster132
+  name: David Heinemeier Hansson
+
+thrid:
+  nick: swistak
+  name: Marcin Raczkowski
\ No newline at end of file
diff --git a/activerecord/test/fixtures/subscriptions.yml b/activerecord/test/fixtures/subscriptions.yml
new file mode 100644
index 0000000000..5a93c12193
--- /dev/null
+++ b/activerecord/test/fixtures/subscriptions.yml
@@ -0,0 +1,12 @@
+webster_awdr:
+  id: 1
+  subscriber_id: webster132
+  book_id: 1
+webster_rfr:
+  id: 2
+  subscriber_id: webster132
+  book_id: 2
+alterself_awdr:
+  id: 3
+  subscriber_id: alterself
+  book_id: 1
diff --git a/activerecord/test/fixtures/taggings.yml b/activerecord/test/fixtures/taggings.yml
new file mode 100644
index 0000000000..d339c12b25
--- /dev/null
+++ b/activerecord/test/fixtures/taggings.yml
@@ -0,0 +1,78 @@
+welcome_general:
+  id: 1
+  tag_id: 1
+  super_tag_id: 2
+  taggable_id: 1
+  taggable_type: Post
+
+thinking_general:
+  id: 2
+  tag_id: 1
+  taggable_id: 2
+  taggable_type: Post
+
+fake:
+  id: 3
+  tag_id: 1
+  taggable_id: 1
+  taggable_type: FakeModel
+
+godfather:
+  id: 4
+  tag_id: 1
+  taggable_id: 1
+  taggable_type: Item
+
+orphaned:
+  id: 5
+  tag_id: 1
+
+misc_post_by_bob:
+  id: 6
+  tag_id: 2
+  taggable_id: 8
+  taggable_type: Post
+
+misc_post_by_mary:
+  id: 7
+  tag_id: 2
+  taggable_id: 9
+  taggable_type: Post
+
+misc_by_bob_blue_first:
+  id: 8
+  tag_id: 3
+  taggable_id: 8
+  taggable_type: Post
+  comment: first
+
+misc_by_bob_blue_second:
+  id: 9
+  tag_id: 3
+  taggable_id: 8
+  taggable_type: Post
+  comment: second
+
+other_by_bob_blue:
+  id: 10
+  tag_id: 3
+  taggable_id: 10
+  taggable_type: Post
+  comment: first
+
+other_by_mary_blue:
+  id: 11
+  tag_id: 3
+  taggable_id: 11
+  taggable_type: Post
+  comment: first
+
+special_comment_rating:
+  id: 12
+  taggable_id: 2
+  taggable_type: Rating
+
+normal_comment_rating:
+  id: 13
+  taggable_id: 1
+  taggable_type: Rating
diff --git a/activerecord/test/fixtures/tags.yml b/activerecord/test/fixtures/tags.yml
new file mode 100644
index 0000000000..d4b7c9a4d5
--- /dev/null
+++ b/activerecord/test/fixtures/tags.yml
@@ -0,0 +1,11 @@
+general:
+  id: 1
+  name: General
+
+misc:
+  id: 2
+  name: Misc
+
+blue:
+  id: 3
+  name: Blue
diff --git a/activerecord/test/fixtures/tasks.yml b/activerecord/test/fixtures/tasks.yml
new file mode 100644
index 0000000000..c38b32b0e5
--- /dev/null
+++ b/activerecord/test/fixtures/tasks.yml
@@ -0,0 +1,7 @@
+# Read about fixtures at http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+first_task:
+  id: 1
+  starting: 2005-03-30t06:30:00.00+01:00
+  ending: 2005-03-30t08:30:00.00+01:00
+another_task:
+  id: 2
diff --git a/activerecord/test/fixtures/teapots.yml b/activerecord/test/fixtures/teapots.yml
new file mode 100644
index 0000000000..ff515beb45
--- /dev/null
+++ b/activerecord/test/fixtures/teapots.yml
@@ -0,0 +1,3 @@
+bob:
+  id: 1
+  name: Bob
diff --git a/activerecord/test/fixtures/to_be_linked/accounts.yml b/activerecord/test/fixtures/to_be_linked/accounts.yml
new file mode 100644
index 0000000000..9e341a15af
--- /dev/null
+++ b/activerecord/test/fixtures/to_be_linked/accounts.yml
@@ -0,0 +1,2 @@
+signals37:
+  name: 37signals
diff --git a/activerecord/test/fixtures/to_be_linked/users.yml b/activerecord/test/fixtures/to_be_linked/users.yml
new file mode 100644
index 0000000000..e2884beda5
--- /dev/null
+++ b/activerecord/test/fixtures/to_be_linked/users.yml
@@ -0,0 +1,10 @@
+david:
+  name: David
+  account: signals37
+
+jamis:
+  name: Jamis
+  account: signals37
+  settings:
+    :symbol: symbol
+    string: string
diff --git a/activerecord/test/fixtures/topics.yml b/activerecord/test/fixtures/topics.yml
new file mode 100644
index 0000000000..4c98b10380
--- /dev/null
+++ b/activerecord/test/fixtures/topics.yml
@@ -0,0 +1,49 @@
+first:
+  id: 1
+  title: The First Topic
+  author_name: David
+  author_email_address: david@loudthinking.com
+  written_on: 2003-07-16t15:28:11.2233+01:00
+  last_read: 2004-04-15
+  bonus_time: 2005-01-30t15:28:00.00+01:00
+  content: "--- Have a nice day\n...\n"
+  approved: false
+  replies_count: 1
+
+second:
+  id: 2
+  title: The Second Topic of the day
+  author_name: Mary
+  written_on: 2004-07-15t15:28:00.0099+01:00
+  content: "--- Have a nice day\n...\n"
+  approved: true
+  replies_count: 0
+  parent_id: 1
+  type: Reply
+
+third:
+  id: 3
+  title: The Third Topic of the day
+  author_name: Carl
+  written_on: 2012-08-12t20:24:22.129346+00:00
+  content: "--- I'm a troll\n...\n"
+  approved: true
+  replies_count: 1
+
+fourth:
+  id: 4
+  title: The Fourth Topic of the day
+  author_name: Carl
+  written_on: 2006-07-15t15:28:00.0099+01:00
+  content: "--- Why not?\n...\n"
+  approved: true
+  type: Reply
+  parent_id: 3
+
+fifth:
+  id: 5
+  title: The Fifth Topic of the day
+  author_name: Jason
+  written_on: 2013-07-13t12:11:00.0099+01:00
+  content: "--- Omakase\n...\n"
+  approved: true
diff --git a/activerecord/test/fixtures/toys.yml b/activerecord/test/fixtures/toys.yml
new file mode 100644
index 0000000000..ae9044ec62
--- /dev/null
+++ b/activerecord/test/fixtures/toys.yml
@@ -0,0 +1,14 @@
+bone:
+  toy_id: 1
+  name: Bone
+  pet_id: 1
+
+doll:
+  toy_id: 2
+  name: Doll
+  pet_id: 2
+
+bulbuli:
+  toy_id: 3
+  name: Bulbuli
+  pet_id: 4
diff --git a/activerecord/test/fixtures/traffic_lights.yml b/activerecord/test/fixtures/traffic_lights.yml
new file mode 100644
index 0000000000..81b4e47959
--- /dev/null
+++ b/activerecord/test/fixtures/traffic_lights.yml
@@ -0,0 +1,10 @@
+uk:
+  location: UK
+  state:
+    - Green
+    - Red
+    - Orange
+  long_state:
+    - "Green, go ahead"
+    - "Red, wait"
+    - "Orange, caution light is about to switch"
\ No newline at end of file
diff --git a/activerecord/test/fixtures/treasures.yml b/activerecord/test/fixtures/treasures.yml
new file mode 100644
index 0000000000..9db15798fd
--- /dev/null
+++ b/activerecord/test/fixtures/treasures.yml
@@ -0,0 +1,10 @@
+diamond:
+  name: $LABEL
+
+sapphire:
+  name: $LABEL
+  looter: redbeard (Pirate)
+
+ruby:
+  name: $LABEL
+  looter: louis (Parrot)
diff --git a/activerecord/test/fixtures/uuid_children.yml b/activerecord/test/fixtures/uuid_children.yml
new file mode 100644
index 0000000000..a7b15016e2
--- /dev/null
+++ b/activerecord/test/fixtures/uuid_children.yml
@@ -0,0 +1,3 @@
+sonny:
+  uuid_parent: daddy
+  name: Sonny
diff --git a/activerecord/test/fixtures/uuid_parents.yml b/activerecord/test/fixtures/uuid_parents.yml
new file mode 100644
index 0000000000..0b40225c5c
--- /dev/null
+++ b/activerecord/test/fixtures/uuid_parents.yml
@@ -0,0 +1,2 @@
+daddy:
+  name: Daddy
diff --git a/activerecord/test/fixtures/variants.yml b/activerecord/test/fixtures/variants.yml
new file mode 100644
index 0000000000..06be30727b
--- /dev/null
+++ b/activerecord/test/fixtures/variants.yml
@@ -0,0 +1,4 @@
+variant_1:
+  id: 1
+  product_id: 1
+  name: Variant
diff --git a/activerecord/test/fixtures/vegetables.yml b/activerecord/test/fixtures/vegetables.yml
new file mode 100644
index 0000000000..b9afbfbb05
--- /dev/null
+++ b/activerecord/test/fixtures/vegetables.yml
@@ -0,0 +1,20 @@
+first_cucumber:
+  id: 1
+  custom_type: Cucumber
+  name: 'my cucumber'
+
+first_cabbage:
+  id: 2
+  custom_type: Cabbage
+  name: 'my cabbage'
+
+second_cabbage:
+  id: 3
+  custom_type: Cabbage
+  name: 'his cabbage'
+
+red_cabbage:
+  id: 4
+  custom_type: RedCabbage
+  name: 'red cabbage'
+  seller_id: 3
\ No newline at end of file
diff --git a/activerecord/test/fixtures/vertices.yml b/activerecord/test/fixtures/vertices.yml
new file mode 100644
index 0000000000..8af0593f75
--- /dev/null
+++ b/activerecord/test/fixtures/vertices.yml
@@ -0,0 +1,4 @@
+<% (1..5).each do |id| %>
+vertex_<%= id %>:
+  id: <%= id %>
+<% end %>
\ No newline at end of file
diff --git a/activerecord/test/fixtures/warehouse-things.yml b/activerecord/test/fixtures/warehouse-things.yml
new file mode 100644
index 0000000000..9e07ba7db5
--- /dev/null
+++ b/activerecord/test/fixtures/warehouse-things.yml
@@ -0,0 +1,3 @@
+one:
+  id: 1
+  value: 1000
\ No newline at end of file
diff --git a/activerecord/test/fixtures/zines.yml b/activerecord/test/fixtures/zines.yml
new file mode 100644
index 0000000000..07dce4db7e
--- /dev/null
+++ b/activerecord/test/fixtures/zines.yml
@@ -0,0 +1,5 @@
+staying_in:
+  title: Staying in '08
+
+going_out:
+  title: Outdoor Pursuits 2k+8
diff --git a/activerecord/test/migrations/10_urban/9_add_expressions.rb b/activerecord/test/migrations/10_urban/9_add_expressions.rb
new file mode 100644
index 0000000000..79a342e574
--- /dev/null
+++ b/activerecord/test/migrations/10_urban/9_add_expressions.rb
@@ -0,0 +1,11 @@
+class AddExpressions < ActiveRecord::Migration
+  def self.up
+    create_table("expressions") do |t|
+      t.column :expression, :string
+    end
+  end
+
+  def self.down
+    drop_table "expressions"
+  end
+end
diff --git a/activerecord/test/migrations/decimal/1_give_me_big_numbers.rb b/activerecord/test/migrations/decimal/1_give_me_big_numbers.rb
new file mode 100644
index 0000000000..0aed7cbd84
--- /dev/null
+++ b/activerecord/test/migrations/decimal/1_give_me_big_numbers.rb
@@ -0,0 +1,15 @@
+class GiveMeBigNumbers < ActiveRecord::Migration
+  def self.up
+    create_table :big_numbers do |table|
+      table.column :bank_balance, :decimal, :precision => 10, :scale => 2
+      table.column :big_bank_balance, :decimal, :precision => 15, :scale => 2
+      table.column :world_population, :decimal, :precision => 10
+      table.column :my_house_population, :decimal, :precision => 2
+      table.column :value_of_e, :decimal
+    end
+  end
+
+  def self.down
+    drop_table :big_numbers
+  end
+end
diff --git a/activerecord/test/migrations/empty/.gitkeep b/activerecord/test/migrations/empty/.gitkeep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/activerecord/test/migrations/empty/.gitkeep
diff --git a/activerecord/test/migrations/magic/1_currencies_have_symbols.rb b/activerecord/test/migrations/magic/1_currencies_have_symbols.rb
new file mode 100644
index 0000000000..c066c068c2
--- /dev/null
+++ b/activerecord/test/migrations/magic/1_currencies_have_symbols.rb
@@ -0,0 +1,12 @@
+# coding: ISO-8859-15
+
+class CurrenciesHaveSymbols < ActiveRecord::Migration
+  def self.up
+    # We use � for default currency symbol
+    add_column "currencies", "symbol", :string, :default => "�"
+  end
+
+  def self.down
+    remove_column "currencies", "symbol"
+  end
+end
diff --git a/activerecord/test/migrations/missing/1000_people_have_middle_names.rb b/activerecord/test/migrations/missing/1000_people_have_middle_names.rb
new file mode 100644
index 0000000000..9fd495b97c
--- /dev/null
+++ b/activerecord/test/migrations/missing/1000_people_have_middle_names.rb
@@ -0,0 +1,9 @@
+class PeopleHaveMiddleNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "middle_name", :string
+  end
+
+  def self.down
+    remove_column "people", "middle_name"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/missing/1_people_have_last_names.rb b/activerecord/test/migrations/missing/1_people_have_last_names.rb
new file mode 100644
index 0000000000..81af5fef5e
--- /dev/null
+++ b/activerecord/test/migrations/missing/1_people_have_last_names.rb
@@ -0,0 +1,9 @@
+class PeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/missing/3_we_need_reminders.rb b/activerecord/test/migrations/missing/3_we_need_reminders.rb
new file mode 100644
index 0000000000..d5e71ce8ef
--- /dev/null
+++ b/activerecord/test/migrations/missing/3_we_need_reminders.rb
@@ -0,0 +1,12 @@
+class WeNeedReminders < ActiveRecord::Migration
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/missing/4_innocent_jointable.rb b/activerecord/test/migrations/missing/4_innocent_jointable.rb
new file mode 100644
index 0000000000..21c9ca5328
--- /dev/null
+++ b/activerecord/test/migrations/missing/4_innocent_jointable.rb
@@ -0,0 +1,12 @@
+class InnocentJointable < ActiveRecord::Migration
+  def self.up
+    create_table("people_reminders", :id => false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/rename/1_we_need_things.rb b/activerecord/test/migrations/rename/1_we_need_things.rb
new file mode 100644
index 0000000000..cdbe0b1679
--- /dev/null
+++ b/activerecord/test/migrations/rename/1_we_need_things.rb
@@ -0,0 +1,11 @@
+class WeNeedThings < ActiveRecord::Migration
+  def self.up
+    create_table("things") do |t|
+      t.column :content, :text
+    end
+  end
+
+  def self.down
+    drop_table "things"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/rename/2_rename_things.rb b/activerecord/test/migrations/rename/2_rename_things.rb
new file mode 100644
index 0000000000..d441b71fc9
--- /dev/null
+++ b/activerecord/test/migrations/rename/2_rename_things.rb
@@ -0,0 +1,9 @@
+class RenameThings < ActiveRecord::Migration
+  def self.up
+    rename_table "things", "awesome_things"
+  end
+
+  def self.down
+    rename_table "awesome_things", "things"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/to_copy/1_people_have_hobbies.rb b/activerecord/test/migrations/to_copy/1_people_have_hobbies.rb
new file mode 100644
index 0000000000..639841f663
--- /dev/null
+++ b/activerecord/test/migrations/to_copy/1_people_have_hobbies.rb
@@ -0,0 +1,9 @@
+class PeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "hobbies", :text
+  end
+
+  def self.down
+    remove_column "people", "hobbies"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy/2_people_have_descriptions.rb b/activerecord/test/migrations/to_copy/2_people_have_descriptions.rb
new file mode 100644
index 0000000000..b3d0b30640
--- /dev/null
+++ b/activerecord/test/migrations/to_copy/2_people_have_descriptions.rb
@@ -0,0 +1,9 @@
+class PeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "description", :text
+  end
+
+  def self.down
+    remove_column "people", "description"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy2/1_create_articles.rb b/activerecord/test/migrations/to_copy2/1_create_articles.rb
new file mode 100644
index 0000000000..0f048d90f7
--- /dev/null
+++ b/activerecord/test/migrations/to_copy2/1_create_articles.rb
@@ -0,0 +1,7 @@
+class CreateArticles < ActiveRecord::Migration
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/migrations/to_copy2/2_create_comments.rb b/activerecord/test/migrations/to_copy2/2_create_comments.rb
new file mode 100644
index 0000000000..0f048d90f7
--- /dev/null
+++ b/activerecord/test/migrations/to_copy2/2_create_comments.rb
@@ -0,0 +1,7 @@
+class CreateArticles < ActiveRecord::Migration
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_name_collision/1_people_have_hobbies.rb b/activerecord/test/migrations/to_copy_with_name_collision/1_people_have_hobbies.rb
new file mode 100644
index 0000000000..e438cf5999
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_name_collision/1_people_have_hobbies.rb
@@ -0,0 +1,9 @@
+class PeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "hobbies", :string
+  end
+
+  def self.down
+    remove_column "people", "hobbies"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_timestamps/20090101010101_people_have_hobbies.rb b/activerecord/test/migrations/to_copy_with_timestamps/20090101010101_people_have_hobbies.rb
new file mode 100644
index 0000000000..639841f663
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_timestamps/20090101010101_people_have_hobbies.rb
@@ -0,0 +1,9 @@
+class PeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "hobbies", :text
+  end
+
+  def self.down
+    remove_column "people", "hobbies"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_timestamps/20090101010202_people_have_descriptions.rb b/activerecord/test/migrations/to_copy_with_timestamps/20090101010202_people_have_descriptions.rb
new file mode 100644
index 0000000000..b3d0b30640
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_timestamps/20090101010202_people_have_descriptions.rb
@@ -0,0 +1,9 @@
+class PeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "description", :text
+  end
+
+  def self.down
+    remove_column "people", "description"
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_timestamps2/20090101010101_create_articles.rb b/activerecord/test/migrations/to_copy_with_timestamps2/20090101010101_create_articles.rb
new file mode 100644
index 0000000000..0f048d90f7
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_timestamps2/20090101010101_create_articles.rb
@@ -0,0 +1,7 @@
+class CreateArticles < ActiveRecord::Migration
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/migrations/to_copy_with_timestamps2/20090101010202_create_comments.rb b/activerecord/test/migrations/to_copy_with_timestamps2/20090101010202_create_comments.rb
new file mode 100644
index 0000000000..2b048edbb5
--- /dev/null
+++ b/activerecord/test/migrations/to_copy_with_timestamps2/20090101010202_create_comments.rb
@@ -0,0 +1,7 @@
+class CreateComments < ActiveRecord::Migration
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/migrations/valid/1_valid_people_have_last_names.rb b/activerecord/test/migrations/valid/1_valid_people_have_last_names.rb
new file mode 100644
index 0000000000..06cb911117
--- /dev/null
+++ b/activerecord/test/migrations/valid/1_valid_people_have_last_names.rb
@@ -0,0 +1,9 @@
+class ValidPeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end
diff --git a/activerecord/test/migrations/valid/2_we_need_reminders.rb b/activerecord/test/migrations/valid/2_we_need_reminders.rb
new file mode 100644
index 0000000000..d5e71ce8ef
--- /dev/null
+++ b/activerecord/test/migrations/valid/2_we_need_reminders.rb
@@ -0,0 +1,12 @@
+class WeNeedReminders < ActiveRecord::Migration
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/valid/3_innocent_jointable.rb b/activerecord/test/migrations/valid/3_innocent_jointable.rb
new file mode 100644
index 0000000000..21c9ca5328
--- /dev/null
+++ b/activerecord/test/migrations/valid/3_innocent_jointable.rb
@@ -0,0 +1,12 @@
+class InnocentJointable < ActiveRecord::Migration
+  def self.up
+    create_table("people_reminders", :id => false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/valid_with_subdirectories/1_valid_people_have_last_names.rb b/activerecord/test/migrations/valid_with_subdirectories/1_valid_people_have_last_names.rb
new file mode 100644
index 0000000000..06cb911117
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_subdirectories/1_valid_people_have_last_names.rb
@@ -0,0 +1,9 @@
+class ValidPeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_subdirectories/sub/2_we_need_reminders.rb b/activerecord/test/migrations/valid_with_subdirectories/sub/2_we_need_reminders.rb
new file mode 100644
index 0000000000..d5e71ce8ef
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_subdirectories/sub/2_we_need_reminders.rb
@@ -0,0 +1,12 @@
+class WeNeedReminders < ActiveRecord::Migration
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/valid_with_subdirectories/sub1/3_innocent_jointable.rb b/activerecord/test/migrations/valid_with_subdirectories/sub1/3_innocent_jointable.rb
new file mode 100644
index 0000000000..21c9ca5328
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_subdirectories/sub1/3_innocent_jointable.rb
@@ -0,0 +1,12 @@
+class InnocentJointable < ActiveRecord::Migration
+  def self.up
+    create_table("people_reminders", :id => false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/migrations/valid_with_timestamps/20100101010101_valid_with_timestamps_people_have_last_names.rb b/activerecord/test/migrations/valid_with_timestamps/20100101010101_valid_with_timestamps_people_have_last_names.rb
new file mode 100644
index 0000000000..1da99ceaba
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_timestamps/20100101010101_valid_with_timestamps_people_have_last_names.rb
@@ -0,0 +1,9 @@
+class ValidWithTimestampsPeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_timestamps/20100201010101_valid_with_timestamps_we_need_reminders.rb b/activerecord/test/migrations/valid_with_timestamps/20100201010101_valid_with_timestamps_we_need_reminders.rb
new file mode 100644
index 0000000000..cb6d735c8b
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_timestamps/20100201010101_valid_with_timestamps_we_need_reminders.rb
@@ -0,0 +1,12 @@
+class ValidWithTimestampsWeNeedReminders < ActiveRecord::Migration
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end
diff --git a/activerecord/test/migrations/valid_with_timestamps/20100301010101_valid_with_timestamps_innocent_jointable.rb b/activerecord/test/migrations/valid_with_timestamps/20100301010101_valid_with_timestamps_innocent_jointable.rb
new file mode 100644
index 0000000000..4bd4b4714d
--- /dev/null
+++ b/activerecord/test/migrations/valid_with_timestamps/20100301010101_valid_with_timestamps_innocent_jointable.rb
@@ -0,0 +1,12 @@
+class ValidWithTimestampsInnocentJointable < ActiveRecord::Migration
+  def self.up
+    create_table("people_reminders", :id => false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end
diff --git a/activerecord/test/migrations/version_check/20131219224947_migration_version_check.rb b/activerecord/test/migrations/version_check/20131219224947_migration_version_check.rb
new file mode 100644
index 0000000000..9d46485a31
--- /dev/null
+++ b/activerecord/test/migrations/version_check/20131219224947_migration_version_check.rb
@@ -0,0 +1,8 @@
+class MigrationVersionCheck < ActiveRecord::Migration
+  def self.up
+    raise "incorrect migration version" unless version == 20131219224947
+  end
+
+  def self.down
+  end
+end
diff --git a/activerecord/test/models/admin.rb b/activerecord/test/models/admin.rb
new file mode 100644
index 0000000000..00e69fbed8
--- /dev/null
+++ b/activerecord/test/models/admin.rb
@@ -0,0 +1,5 @@
+module Admin
+  def self.table_name_prefix
+    'admin_'
+  end
+end
\ No newline at end of file
diff --git a/activerecord/test/models/admin/account.rb b/activerecord/test/models/admin/account.rb
new file mode 100644
index 0000000000..46de28aae1
--- /dev/null
+++ b/activerecord/test/models/admin/account.rb
@@ -0,0 +1,3 @@
+class Admin::Account < ActiveRecord::Base
+  has_many :users
+end
\ No newline at end of file
diff --git a/activerecord/test/models/admin/randomly_named_c1.rb b/activerecord/test/models/admin/randomly_named_c1.rb
new file mode 100644
index 0000000000..2f81d5b831
--- /dev/null
+++ b/activerecord/test/models/admin/randomly_named_c1.rb
@@ -0,0 +1,3 @@
+class Admin::ClassNameThatDoesNotFollowCONVENTIONS < ActiveRecord::Base

+  self.table_name = :randomly_named_table

+end

diff --git a/activerecord/test/models/admin/user.rb b/activerecord/test/models/admin/user.rb
new file mode 100644
index 0000000000..48a110bd23
--- /dev/null
+++ b/activerecord/test/models/admin/user.rb
@@ -0,0 +1,40 @@
+class Admin::User < ActiveRecord::Base
+  class Coder
+    def initialize(default = {})
+      @default = default
+    end
+
+    def dump(o)
+      ActiveSupport::JSON.encode(o || @default)
+    end
+
+    def load(s)
+      s.present? ? ActiveSupport::JSON.decode(s) : @default.clone
+    end
+  end
+
+  belongs_to :account
+  store :params, accessors: [ :token ], coder: YAML
+  store :settings, :accessors => [ :color, :homepage ]
+  store_accessor :settings, :favorite_food
+  store :preferences, :accessors => [ :remember_login ]
+  store :json_data, :accessors => [ :height, :weight ], :coder => Coder.new
+  store :json_data_empty, :accessors => [ :is_a_good_guy ], :coder => Coder.new
+
+  def phone_number
+    read_store_attribute(:settings, :phone_number).gsub(/(\d{3})(\d{3})(\d{4})/,'(\1) \2-\3')
+  end
+
+  def phone_number=(value)
+    write_store_attribute(:settings, :phone_number, value && value.gsub(/[^\d]/,''))
+  end
+
+  def color
+    super || 'red'
+  end
+
+  def color=(value)
+    value = 'blue' unless %w(black red green blue).include?(value)
+    super
+  end
+end
diff --git a/activerecord/test/models/aircraft.rb b/activerecord/test/models/aircraft.rb
new file mode 100644
index 0000000000..1f35ef45da
--- /dev/null
+++ b/activerecord/test/models/aircraft.rb
@@ -0,0 +1,4 @@
+class Aircraft < ActiveRecord::Base
+  self.pluralize_table_names = false
+  has_many :engines, :foreign_key => "car_id"
+end
diff --git a/activerecord/test/models/arunit2_model.rb b/activerecord/test/models/arunit2_model.rb
new file mode 100644
index 0000000000..04b8b15d3d
--- /dev/null
+++ b/activerecord/test/models/arunit2_model.rb
@@ -0,0 +1,3 @@
+class ARUnit2Model < ActiveRecord::Base
+  self.abstract_class = true
+end
diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
new file mode 100644
index 0000000000..8949cf5826
--- /dev/null
+++ b/activerecord/test/models/author.rb
@@ -0,0 +1,202 @@
+class Author < ActiveRecord::Base
+  has_many :posts
+  has_one :post
+  has_many :very_special_comments, :through => :posts
+  has_many :posts_with_comments, -> { includes(:comments) }, :class_name => "Post"
+  has_many :popular_grouped_posts, -> { includes(:comments).group("type").having("SUM(comments_count) > 1").select("type") }, :class_name => "Post"
+  has_many :posts_with_comments_sorted_by_comment_id, -> { includes(:comments).order('comments.id') }, :class_name => "Post"
+  has_many :posts_sorted_by_id_limited, -> { order('posts.id').limit(1) }, :class_name => "Post"
+  has_many :posts_with_categories, -> { includes(:categories) }, :class_name => "Post"
+  has_many :posts_with_comments_and_categories, -> { includes(:comments, :categories).order("posts.id") }, :class_name => "Post"
+  has_many :posts_with_special_categorizations, :class_name => 'PostWithSpecialCategorization'
+  has_one  :post_about_thinking, -> { where("posts.title like '%thinking%'") }, :class_name => 'Post'
+  has_one  :post_about_thinking_with_last_comment, -> { where("posts.title like '%thinking%'").includes(:last_comment) }, :class_name => 'Post'
+  has_many :comments, through: :posts do
+    def ratings
+      Rating.joins(:comment).merge(self)
+    end
+  end
+  has_many :comments_containing_the_letter_e, :through => :posts, :source => :comments
+  has_many :comments_with_order_and_conditions, -> { order('comments.body').where("comments.body like 'Thank%'") }, :through => :posts, :source => :comments
+  has_many :comments_with_include, -> { includes(:post) }, :through => :posts, :source => :comments
+
+  has_many :first_posts
+  has_many :comments_on_first_posts, -> { order('posts.id desc, comments.id asc') }, :through => :first_posts, :source => :comments
+
+  has_one :first_post
+  has_one :comment_on_first_post, -> { order('posts.id desc, comments.id asc') }, :through => :first_post, :source => :comments
+
+  has_many :thinking_posts, -> { where(:title => 'So I was thinking') }, :dependent => :delete_all, :class_name => 'Post'
+  has_many :welcome_posts, -> { where(:title => 'Welcome to the weblog') }, :class_name => 'Post'
+
+  has_many :welcome_posts_with_one_comment,
+           -> { where(title: 'Welcome to the weblog').where('comments_count = ?', 1) },
+           class_name: 'Post'
+  has_many :welcome_posts_with_comments,
+           -> { where(title: 'Welcome to the weblog').where(Post.arel_table[:comments_count].gt(0)) },
+           class_name: 'Post'
+
+  has_many :comments_desc, -> { order('comments.id DESC') }, :through => :posts, :source => :comments
+  has_many :funky_comments, :through => :posts, :source => :comments
+  has_many :ordered_uniq_comments, -> { distinct.order('comments.id') }, :through => :posts, :source => :comments
+  has_many :ordered_uniq_comments_desc, -> { distinct.order('comments.id DESC') }, :through => :posts, :source => :comments
+  has_many :readonly_comments, -> { readonly }, :through => :posts, :source => :comments
+
+  has_many :special_posts
+  has_many :special_post_comments, :through => :special_posts, :source => :comments
+
+  has_many :sti_posts, :class_name => 'StiPost'
+  has_many :sti_post_comments, :through => :sti_posts, :source => :comments
+
+  has_many :special_nonexistant_posts, -> { where("posts.body = 'nonexistant'") }, :class_name => "SpecialPost"
+  has_many :special_nonexistant_post_comments, -> { where('comments.post_id' => 0) }, :through => :special_nonexistant_posts, :source => :comments
+  has_many :nonexistant_comments, :through => :posts
+
+  has_many :hello_posts, -> { where "posts.body = 'hello'" }, :class_name => "Post"
+  has_many :hello_post_comments, :through => :hello_posts, :source => :comments
+  has_many :posts_with_no_comments, -> { where('comments.id' => nil).includes(:comments) }, :class_name => 'Post'
+
+  has_many :hello_posts_with_hash_conditions, -> { where(:body => 'hello') }, :class_name => "Post"
+  has_many :hello_post_comments_with_hash_conditions, :through =>
+:hello_posts_with_hash_conditions, :source => :comments
+
+  has_many :other_posts,          :class_name => "Post"
+  has_many :posts_with_callbacks, :class_name => "Post", :before_add => :log_before_adding,
+           :after_add     => :log_after_adding,
+           :before_remove => :log_before_removing,
+           :after_remove  => :log_after_removing
+  has_many :posts_with_proc_callbacks, :class_name => "Post",
+           :before_add    => Proc.new {|o, r| o.post_log << "before_adding#{r.id || '<new>'}"},
+           :after_add     => Proc.new {|o, r| o.post_log << "after_adding#{r.id || '<new>'}"},
+           :before_remove => Proc.new {|o, r| o.post_log << "before_removing#{r.id}"},
+           :after_remove  => Proc.new {|o, r| o.post_log << "after_removing#{r.id}"}
+  has_many :posts_with_multiple_callbacks, :class_name => "Post",
+           :before_add => [:log_before_adding, Proc.new {|o, r| o.post_log << "before_adding_proc#{r.id || '<new>'}"}],
+           :after_add  => [:log_after_adding,  Proc.new {|o, r| o.post_log << "after_adding_proc#{r.id || '<new>'}"}]
+  has_many :unchangable_posts, :class_name => "Post", :before_add => :raise_exception, :after_add => :log_after_adding
+
+  has_many :categorizations
+  has_many :categories, :through => :categorizations
+  has_many :named_categories, :through => :categorizations
+
+  has_many :special_categorizations
+  has_many :special_categories, :through => :special_categorizations, :source => :category
+  has_one  :special_category,   :through => :special_categorizations, :source => :category
+
+  has_many :categories_like_general, -> { where(:name => 'General') }, :through => :categorizations, :source => :category, :class_name => 'Category'
+
+  has_many :categorized_posts, :through => :categorizations, :source => :post
+  has_many :unique_categorized_posts, -> { distinct }, :through => :categorizations, :source => :post
+
+  has_many :nothings, :through => :kateggorisatons, :class_name => 'Category'
+
+  has_many :author_favorites
+  has_many :favorite_authors, -> { order('name') }, :through => :author_favorites
+
+  has_many :taggings,        :through => :posts, :source => :taggings
+  has_many :taggings_2,      :through => :posts, :source => :tagging
+  has_many :tags,            :through => :posts
+  has_many :post_categories, :through => :posts, :source => :categories
+  has_many :tagging_tags,    :through => :taggings, :source => :tag
+
+  has_many :similar_posts, -> { distinct }, :through => :tags, :source => :tagged_posts
+  has_many :distinct_tags, -> { select("DISTINCT tags.*").order("tags.name") }, :through => :posts, :source => :tags
+
+  has_many :tags_with_primary_key, :through => :posts
+
+  has_many :books
+  has_many :subscriptions,        :through => :books
+  has_many :subscribers, -> { order("subscribers.nick") }, :through => :subscriptions
+  has_many :distinct_subscribers, -> { select("DISTINCT subscribers.*").order("subscribers.nick") }, :through => :subscriptions, :source => :subscriber
+
+  has_one :essay, :primary_key => :name, :as => :writer
+  has_one :essay_category, :through => :essay, :source => :category
+  has_one :essay_owner, :through => :essay, :source => :owner
+
+  has_one :essay_2, :primary_key => :name, :class_name => 'Essay', :foreign_key => :author_id
+  has_one :essay_category_2, :through => :essay_2, :source => :category
+
+  has_many :essays, :primary_key => :name, :as => :writer
+  has_many :essay_categories, :through => :essays, :source => :category
+  has_many :essay_owners, :through => :essays, :source => :owner
+
+  has_many :essays_2, :primary_key => :name, :class_name => 'Essay', :foreign_key => :author_id
+  has_many :essay_categories_2, :through => :essays_2, :source => :category
+
+  belongs_to :owned_essay, :primary_key => :name, :class_name => 'Essay'
+  has_one :owned_essay_category, :through => :owned_essay, :source => :category
+
+  belongs_to :author_address,       :dependent => :destroy
+  belongs_to :author_address_extra, :dependent => :delete, :class_name => "AuthorAddress"
+
+  has_many :category_post_comments, :through => :categories, :source => :post_comments
+
+  has_many :misc_posts, -> { where(:posts => { :title => ['misc post by bob', 'misc post by mary'] }) }, :class_name => 'Post'
+  has_many :misc_post_first_blue_tags, :through => :misc_posts, :source => :first_blue_tags
+
+  has_many :misc_post_first_blue_tags_2, -> { where(:posts => { :title => ['misc post by bob', 'misc post by mary'] }) },
+           :through => :posts, :source => :first_blue_tags_2
+
+  has_many :posts_with_default_include, :class_name => 'PostWithDefaultInclude'
+  has_many :comments_on_posts_with_default_include, :through => :posts_with_default_include, :source => :comments
+
+  has_many :posts_with_signature, ->(record) { where("posts.title LIKE ?", "%by #{record.name.downcase}%") }, class_name: "Post"
+
+  scope :relation_include_posts, -> { includes(:posts) }
+  scope :relation_include_tags,  -> { includes(:tags) }
+
+  attr_accessor :post_log
+  after_initialize :set_post_log
+
+  def set_post_log
+    @post_log = []
+  end
+
+  def label
+    "#{id}-#{name}"
+  end
+
+  def social
+    %w(twitter github)
+  end
+
+  validates_presence_of :name
+
+  private
+    def log_before_adding(object)
+      @post_log << "before_adding#{object.id || '<new>'}"
+    end
+
+    def log_after_adding(object)
+      @post_log << "after_adding#{object.id}"
+    end
+
+    def log_before_removing(object)
+      @post_log << "before_removing#{object.id}"
+    end
+
+    def log_after_removing(object)
+      @post_log << "after_removing#{object.id}"
+    end
+
+    def raise_exception(object)
+      raise Exception.new("You can't add a post")
+    end
+end
+
+class AuthorAddress < ActiveRecord::Base
+  has_one :author
+
+  def self.destroyed_author_address_ids
+    @destroyed_author_address_ids ||= []
+  end
+
+  before_destroy do |author_address|
+    AuthorAddress.destroyed_author_address_ids << author_address.id
+  end
+end
+
+class AuthorFavorite < ActiveRecord::Base
+  belongs_to :author
+  belongs_to :favorite_author, :class_name => "Author"
+end
diff --git a/activerecord/test/models/auto_id.rb b/activerecord/test/models/auto_id.rb
new file mode 100644
index 0000000000..82c6544bd5
--- /dev/null
+++ b/activerecord/test/models/auto_id.rb
@@ -0,0 +1,4 @@
+class AutoId < ActiveRecord::Base
+  self.table_name = "auto_id_tests"
+  self.primary_key = "auto_id"
+end
diff --git a/activerecord/test/models/autoloadable/extra_firm.rb b/activerecord/test/models/autoloadable/extra_firm.rb
new file mode 100644
index 0000000000..5578ba0d9b
--- /dev/null
+++ b/activerecord/test/models/autoloadable/extra_firm.rb
@@ -0,0 +1,2 @@
+class ExtraFirm < Company
+end
diff --git a/activerecord/test/models/binary.rb b/activerecord/test/models/binary.rb
new file mode 100644
index 0000000000..950c459199
--- /dev/null
+++ b/activerecord/test/models/binary.rb
@@ -0,0 +1,2 @@
+class Binary < ActiveRecord::Base
+end
\ No newline at end of file
diff --git a/activerecord/test/models/bird.rb b/activerecord/test/models/bird.rb
new file mode 100644
index 0000000000..dff099c1fb
--- /dev/null
+++ b/activerecord/test/models/bird.rb
@@ -0,0 +1,12 @@
+class Bird < ActiveRecord::Base
+  belongs_to :pirate
+  validates_presence_of :name
+
+  accepts_nested_attributes_for :pirate
+
+  attr_accessor :cancel_save_from_callback
+  before_save :cancel_save_callback_method, :if => :cancel_save_from_callback
+  def cancel_save_callback_method
+    false
+  end
+end
diff --git a/activerecord/test/models/book.rb b/activerecord/test/models/book.rb
new file mode 100644
index 0000000000..2170018068
--- /dev/null
+++ b/activerecord/test/models/book.rb
@@ -0,0 +1,18 @@
+class Book < ActiveRecord::Base
+  has_many :authors
+
+  has_many :citations, :foreign_key => 'book1_id'
+  has_many :references, -> { distinct }, through: :citations, source: :reference_of
+
+  has_many :subscriptions
+  has_many :subscribers, through: :subscriptions
+
+  enum status: [:proposed, :written, :published]
+  enum read_status: {unread: 0, reading: 2, read: 3}
+  enum nullable_status: [:single, :married]
+
+  def published!
+    super
+    "do publish work..."
+  end
+end
diff --git a/activerecord/test/models/boolean.rb b/activerecord/test/models/boolean.rb
new file mode 100644
index 0000000000..7bae22e5f9
--- /dev/null
+++ b/activerecord/test/models/boolean.rb
@@ -0,0 +1,2 @@
+class Boolean < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/bulb.rb b/activerecord/test/models/bulb.rb
new file mode 100644
index 0000000000..831a0d5387
--- /dev/null
+++ b/activerecord/test/models/bulb.rb
@@ -0,0 +1,51 @@
+class Bulb < ActiveRecord::Base
+  default_scope { where(:name => 'defaulty') }
+  belongs_to :car, :touch => true
+
+  attr_reader :scope_after_initialize, :attributes_after_initialize
+
+  after_initialize :record_scope_after_initialize
+  def record_scope_after_initialize
+    @scope_after_initialize = self.class.all
+  end
+
+  after_initialize :record_attributes_after_initialize
+  def record_attributes_after_initialize
+    @attributes_after_initialize = attributes.dup
+  end
+
+  def color=(color)
+    self[:color] = color.upcase + "!"
+  end
+
+  def self.new(attributes = {}, &block)
+    bulb_type = (attributes || {}).delete(:bulb_type)
+
+    if bulb_type.present?
+      bulb_class = "#{bulb_type.to_s.camelize}Bulb".constantize
+      bulb_class.new(attributes, &block)
+    else
+      super
+    end
+  end
+end
+
+class CustomBulb < Bulb
+  after_initialize :set_awesomeness
+
+  def set_awesomeness
+    self.frickinawesome = true if name == 'Dude'
+  end
+end
+
+class FunkyBulb < Bulb
+  before_destroy do
+    raise "before_destroy was called"
+  end
+end
+
+class FailedBulb < Bulb
+  before_destroy do
+    false
+  end
+end
diff --git a/activerecord/test/models/cake_designer.rb b/activerecord/test/models/cake_designer.rb
new file mode 100644
index 0000000000..9c57ef573a
--- /dev/null
+++ b/activerecord/test/models/cake_designer.rb
@@ -0,0 +1,3 @@
+class CakeDesigner < ActiveRecord::Base
+  has_one :chef, as: :employable
+end
diff --git a/activerecord/test/models/car.rb b/activerecord/test/models/car.rb
new file mode 100644
index 0000000000..db0f93f63b
--- /dev/null
+++ b/activerecord/test/models/car.rb
@@ -0,0 +1,26 @@
+class Car < ActiveRecord::Base
+  has_many :bulbs
+  has_many :all_bulbs, -> { unscope where: :name }, class_name: "Bulb"
+  has_many :funky_bulbs, class_name: 'FunkyBulb', dependent: :destroy
+  has_many :failed_bulbs, class_name: 'FailedBulb', dependent: :destroy
+  has_many :foo_bulbs, -> { where(:name => 'foo') }, :class_name => "Bulb"
+
+  has_one :bulb
+
+  has_many :tyres
+  has_many :engines, :dependent => :destroy
+  has_many :wheels, :as => :wheelable, :dependent => :destroy
+
+  scope :incl_tyres, -> { includes(:tyres) }
+  scope :incl_engines, -> { includes(:engines) }
+
+  scope :order_using_new_style,  -> { order('name asc') }
+end
+
+class CoolCar < Car
+  default_scope { order('name desc') }
+end
+
+class FastCar < Car
+  default_scope { order('name desc') }
+end
diff --git a/activerecord/test/models/categorization.rb b/activerecord/test/models/categorization.rb
new file mode 100644
index 0000000000..6588531de6
--- /dev/null
+++ b/activerecord/test/models/categorization.rb
@@ -0,0 +1,19 @@
+class Categorization < ActiveRecord::Base
+  belongs_to :post
+  belongs_to :category
+  belongs_to :named_category, :class_name => 'Category', :foreign_key => :named_category_name, :primary_key => :name
+  belongs_to :author
+
+  has_many :post_taggings, :through => :author, :source => :taggings
+
+  belongs_to :author_using_custom_pk,  :class_name => 'Author', :foreign_key => :author_id, :primary_key => :author_address_extra_id
+  has_many   :authors_using_custom_pk, :class_name => 'Author', :foreign_key => :id,        :primary_key => :category_id
+end
+
+class SpecialCategorization < ActiveRecord::Base
+  self.table_name = 'categorizations'
+  default_scope { where(:special => true) }
+
+  belongs_to :author
+  belongs_to :category
+end
diff --git a/activerecord/test/models/category.rb b/activerecord/test/models/category.rb
new file mode 100644
index 0000000000..272223e1d8
--- /dev/null
+++ b/activerecord/test/models/category.rb
@@ -0,0 +1,35 @@
+class Category < ActiveRecord::Base
+  has_and_belongs_to_many :posts
+  has_and_belongs_to_many :special_posts, :class_name => "Post"
+  has_and_belongs_to_many :other_posts, :class_name => "Post"
+  has_and_belongs_to_many :posts_with_authors_sorted_by_author_id, -> { includes(:authors).order("authors.id") }, :class_name => "Post"
+
+  has_and_belongs_to_many :select_testing_posts,
+                          -> { select 'posts.*, 1 as correctness_marker' },
+                          :class_name => 'Post',
+                          :foreign_key => 'category_id',
+                          :association_foreign_key => 'post_id'
+
+  has_and_belongs_to_many :post_with_conditions,
+                          -> { where :title => 'Yet Another Testing Title' },
+                          :class_name => 'Post'
+
+  has_and_belongs_to_many :popular_grouped_posts, -> { group("posts.type").having("sum(comments.post_id) > 2").includes(:comments) }, :class_name => "Post"
+  has_and_belongs_to_many :posts_grouped_by_title, -> { group("title").select("title") }, :class_name => "Post"
+
+  def self.what_are_you
+    'a category...'
+  end
+
+  has_many :categorizations
+  has_many :special_categorizations
+  has_many :post_comments, :through => :posts, :source => :comments
+
+  has_many :authors, :through => :categorizations
+  has_many :authors_with_select, -> { select 'authors.*, categorizations.post_id' }, :through => :categorizations, :source => :author
+
+  scope :general, -> { where(:name => 'General') }
+end
+
+class SpecialCategory < Category
+end
diff --git a/activerecord/test/models/chef.rb b/activerecord/test/models/chef.rb
new file mode 100644
index 0000000000..67a4e54f06
--- /dev/null
+++ b/activerecord/test/models/chef.rb
@@ -0,0 +1,3 @@
+class Chef < ActiveRecord::Base
+  belongs_to :employable, polymorphic: true
+end
diff --git a/activerecord/test/models/citation.rb b/activerecord/test/models/citation.rb
new file mode 100644
index 0000000000..3d87eb795c
--- /dev/null
+++ b/activerecord/test/models/citation.rb
@@ -0,0 +1,3 @@
+class Citation < ActiveRecord::Base
+  belongs_to :reference_of, :class_name => "Book", :foreign_key => :book2_id
+end
diff --git a/activerecord/test/models/club.rb b/activerecord/test/models/club.rb
new file mode 100644
index 0000000000..6ceafe5858
--- /dev/null
+++ b/activerecord/test/models/club.rb
@@ -0,0 +1,23 @@
+class Club < ActiveRecord::Base
+  has_one :membership
+  has_many :memberships, :inverse_of => false
+  has_many :members, :through => :memberships
+  has_one :sponsor
+  has_one :sponsored_member, :through => :sponsor, :source => :sponsorable, :source_type => "Member"
+  belongs_to :category
+
+  has_many :favourites, -> { where(memberships: { favourite: true }) }, through: :memberships, source: :member
+
+  private
+
+  def private_method
+    "I'm sorry sir, this is a *private* club, not a *pirate* club"
+  end
+end
+
+class SuperClub < ActiveRecord::Base
+  self.table_name = "clubs"
+
+  has_many :memberships, class_name: 'SuperMembership', foreign_key: 'club_id'
+  has_many :members, through: :memberships
+end
diff --git a/activerecord/test/models/college.rb b/activerecord/test/models/college.rb
new file mode 100644
index 0000000000..501af4a8dd
--- /dev/null
+++ b/activerecord/test/models/college.rb
@@ -0,0 +1,10 @@
+require_dependency 'models/arunit2_model'
+require 'active_support/core_ext/object/with_options'
+
+class College < ARUnit2Model
+  has_many :courses
+
+  with_options dependent: :destroy do |assoc|
+    assoc.has_many :students, -> { where(active: true) }
+  end
+end
diff --git a/activerecord/test/models/column.rb b/activerecord/test/models/column.rb
new file mode 100644
index 0000000000..499358b4cf
--- /dev/null
+++ b/activerecord/test/models/column.rb
@@ -0,0 +1,3 @@
+class Column < ActiveRecord::Base
+  belongs_to :record
+end
diff --git a/activerecord/test/models/column_name.rb b/activerecord/test/models/column_name.rb
new file mode 100644
index 0000000000..460eb4fe20
--- /dev/null
+++ b/activerecord/test/models/column_name.rb
@@ -0,0 +1,3 @@
+class ColumnName < ActiveRecord::Base
+  self.table_name = "colnametests"
+end
diff --git a/activerecord/test/models/comment.rb b/activerecord/test/models/comment.rb
new file mode 100644
index 0000000000..15970758db
--- /dev/null
+++ b/activerecord/test/models/comment.rb
@@ -0,0 +1,53 @@
+class Comment < ActiveRecord::Base
+  scope :limit_by, lambda {|l| limit(l) }
+  scope :containing_the_letter_e, -> { where("comments.body LIKE '%e%'") }
+  scope :not_again, -> { where("comments.body NOT LIKE '%again%'") }
+  scope :for_first_post, -> { where(:post_id => 1) }
+  scope :for_first_author, -> { joins(:post).where("posts.author_id" => 1) }
+  scope :created, -> { all }
+
+  belongs_to :post, :counter_cache => true
+  belongs_to :author,   polymorphic: true
+  belongs_to :resource, polymorphic: true
+
+  has_many :ratings
+
+  belongs_to :first_post, :foreign_key => :post_id
+
+  has_many :children, :class_name => 'Comment', :foreign_key => :parent_id
+  belongs_to :parent, :class_name => 'Comment', :counter_cache => :children_count
+
+  def self.what_are_you
+    'a comment...'
+  end
+
+  def self.search_by_type(q)
+    where("#{QUOTED_TYPE} = ?", q)
+  end
+
+  def self.all_as_method
+    all
+  end
+  scope :all_as_scope, -> { all }
+
+  def to_s
+    body
+  end
+end
+
+class SpecialComment < Comment
+end
+
+class SubSpecialComment < SpecialComment
+end
+
+class VerySpecialComment < Comment
+end
+
+class CommentThatAutomaticallyAltersPostBody < Comment
+  belongs_to :post, class_name: "PostThatLoadsCommentsInAnAfterSaveHook", foreign_key: :post_id
+
+  after_save do |comment|
+    comment.post.update_attributes(body: "Automatically altered")
+  end
+end
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
new file mode 100644
index 0000000000..76411ecb37
--- /dev/null
+++ b/activerecord/test/models/company.rb
@@ -0,0 +1,223 @@
+class AbstractCompany < ActiveRecord::Base
+  self.abstract_class = true
+end
+
+class Company < AbstractCompany
+  self.sequence_name = :companies_nonstd_seq
+
+  validates_presence_of :name
+
+  has_one :dummy_account, :foreign_key => "firm_id", :class_name => "Account"
+  has_many :contracts
+  has_many :developers, :through => :contracts
+
+  scope :of_first_firm, lambda {
+    joins(:account => :firm).
+    where('firms.id' => 1)
+  }
+
+  def arbitrary_method
+    "I am Jack's profound disappointment"
+  end
+
+  private
+
+  def private_method
+    "I am Jack's innermost fears and aspirations"
+  end
+end
+
+module Namespaced
+  class Company < ::Company
+  end
+
+  class Firm < ::Company
+    has_many :clients, :class_name => 'Namespaced::Client'
+  end
+
+  class Client < ::Company
+  end
+end
+
+class Firm < Company
+  to_param :name
+
+  has_many :clients, -> { order "id" }, :dependent => :destroy, :before_remove => :log_before_remove, :after_remove  => :log_after_remove
+  has_many :unsorted_clients, :class_name => "Client"
+  has_many :unsorted_clients_with_symbol, :class_name => :Client
+  has_many :clients_sorted_desc, -> { order "id DESC" }, :class_name => "Client"
+  has_many :clients_of_firm, -> { order "id" }, :foreign_key => "client_of", :class_name => "Client", :inverse_of => :firm
+  has_many :clients_ordered_by_name, -> { order "name" }, :class_name => "Client"
+  has_many :unvalidated_clients_of_firm, :foreign_key => "client_of", :class_name => "Client", :validate => false
+  has_many :dependent_clients_of_firm, -> { order "id" }, :foreign_key => "client_of", :class_name => "Client", :dependent => :destroy
+  has_many :exclusively_dependent_clients_of_firm, -> { order "id" }, :foreign_key => "client_of", :class_name => "Client", :dependent => :delete_all
+  has_many :limited_clients, -> { limit 1 }, :class_name => "Client"
+  has_many :clients_with_interpolated_conditions, ->(firm) { where "rating > #{firm.rating}" }, :class_name => "Client"
+  has_many :clients_like_ms, -> { where("name = 'Microsoft'").order("id") }, :class_name => "Client"
+  has_many :clients_like_ms_with_hash_conditions, -> { where(:name => 'Microsoft').order("id") }, :class_name => "Client"
+  has_many :plain_clients, :class_name => 'Client'
+  has_many :clients_using_primary_key, :class_name => 'Client',
+           :primary_key => 'name', :foreign_key => 'firm_name'
+  has_many :clients_using_primary_key_with_delete_all, :class_name => 'Client',
+           :primary_key => 'name', :foreign_key => 'firm_name', :dependent => :delete_all
+  has_many :clients_grouped_by_firm_id, -> { group("firm_id").select("firm_id") }, :class_name => "Client"
+  has_many :clients_grouped_by_name, -> { group("name").select("name") }, :class_name => "Client"
+
+  has_one :account, :foreign_key => "firm_id", :dependent => :destroy, :validate => true
+  has_one :unvalidated_account, :foreign_key => "firm_id", :class_name => 'Account', :validate => false
+  has_one :account_with_select, -> { select("id, firm_id") }, :foreign_key => "firm_id", :class_name=>'Account'
+  has_one :readonly_account, -> { readonly }, :foreign_key => "firm_id", :class_name => "Account"
+  # added order by id as in fixtures there are two accounts for Rails Core
+  # Oracle tests were failing because of that as the second fixture was selected
+  has_one :account_using_primary_key, -> { order('id') }, :primary_key => "firm_id", :class_name => "Account"
+  has_one :account_using_foreign_and_primary_keys, :foreign_key => "firm_name", :primary_key => "name", :class_name => "Account"
+  has_one :deletable_account, :foreign_key => "firm_id", :class_name => "Account", :dependent => :delete
+
+  has_one :account_limit_500_with_hash_conditions, -> { where :credit_limit => 500 }, :foreign_key => "firm_id", :class_name => "Account"
+
+  has_one :unautosaved_account, :foreign_key => "firm_id", :class_name => 'Account', :autosave => false
+  has_many :accounts
+  has_many :unautosaved_accounts, :foreign_key => "firm_id", :class_name => 'Account', :autosave => false
+
+  has_many :association_with_references, -> { references(:foo) }, :class_name => 'Client'
+
+  def log
+    @log ||= []
+  end
+
+  private
+    def log_before_remove(record)
+      log << "before_remove#{record.id}"
+    end
+
+    def log_after_remove(record)
+      log << "after_remove#{record.id}"
+    end
+end
+
+class DependentFirm < Company
+  has_one :account, :foreign_key => "firm_id", :dependent => :nullify
+  has_many :companies, :foreign_key => 'client_of', :dependent => :nullify
+  has_one :company, :foreign_key => 'client_of', :dependent => :nullify
+end
+
+class RestrictedWithExceptionFirm < Company
+  has_one :account, -> { order("id") }, :foreign_key => "firm_id", :dependent => :restrict_with_exception
+  has_many :companies, -> { order("id") }, :foreign_key => 'client_of', :dependent => :restrict_with_exception
+end
+
+class RestrictedWithErrorFirm < Company
+  has_one :account, -> { order("id") }, :foreign_key => "firm_id", :dependent => :restrict_with_error
+  has_many :companies, -> { order("id") }, :foreign_key => 'client_of', :dependent => :restrict_with_error
+end
+
+class Client < Company
+  belongs_to :firm, :foreign_key => "client_of"
+  belongs_to :firm_with_basic_id, :class_name => "Firm", :foreign_key => "firm_id"
+  belongs_to :firm_with_select, -> { select("id") }, :class_name => "Firm", :foreign_key => "firm_id"
+  belongs_to :firm_with_other_name, :class_name => "Firm", :foreign_key => "client_of"
+  belongs_to :firm_with_condition, -> { where "1 = ?", 1 }, :class_name => "Firm", :foreign_key => "client_of"
+  belongs_to :firm_with_primary_key, :class_name => "Firm", :primary_key => "name", :foreign_key => "firm_name"
+  belongs_to :firm_with_primary_key_symbols, :class_name => "Firm", :primary_key => :name, :foreign_key => :firm_name
+  belongs_to :readonly_firm, -> { readonly }, :class_name => "Firm", :foreign_key => "firm_id"
+  belongs_to :bob_firm, -> { where :name => "Bob" }, :class_name => "Firm", :foreign_key => "client_of"
+  has_many :accounts, :through => :firm, :source => :accounts
+  belongs_to :account
+
+  validate do
+    firm
+  end
+
+  class RaisedOnSave < RuntimeError; end
+  attr_accessor :raise_on_save
+  before_save do
+    raise RaisedOnSave if raise_on_save
+  end
+
+  class RaisedOnDestroy < RuntimeError; end
+  attr_accessor :raise_on_destroy
+  before_destroy do
+    raise RaisedOnDestroy if raise_on_destroy
+  end
+
+  # Record destruction so we can test whether firm.clients.clear has
+  # is calling client.destroy, deleting from the database, or setting
+  # foreign keys to NULL.
+  def self.destroyed_client_ids
+    @destroyed_client_ids ||= Hash.new { |h,k| h[k] = [] }
+  end
+
+  before_destroy do |client|
+    if client.firm
+      Client.destroyed_client_ids[client.firm.id] << client.id
+    end
+    true
+  end
+
+  before_destroy :overwrite_to_raise
+
+  # Used to test that read and question methods are not generated for these attributes
+  def rating?
+    query_attribute :rating
+  end
+
+  def overwrite_to_raise
+  end
+
+  class << self
+    private
+
+    def private_method
+      "darkness"
+    end
+  end
+end
+
+class ExclusivelyDependentFirm < Company
+  has_one :account, :foreign_key => "firm_id", :dependent => :delete
+  has_many :dependent_sanitized_conditional_clients_of_firm, -> { order("id").where("name = 'BigShot Inc.'") }, :foreign_key => "client_of", :class_name => "Client", :dependent => :delete_all
+  has_many :dependent_conditional_clients_of_firm, -> { order("id").where("name = ?", 'BigShot Inc.') }, :foreign_key => "client_of", :class_name => "Client", :dependent => :delete_all
+end
+
+class SpecialClient < Client
+end
+
+class VerySpecialClient < SpecialClient
+end
+
+class Account < ActiveRecord::Base
+  belongs_to :firm, :class_name => 'Company'
+  belongs_to :unautosaved_firm, :foreign_key => "firm_id", :class_name => "Firm", :autosave => false
+
+  alias_attribute :available_credit, :credit_limit
+
+  def self.destroyed_account_ids
+    @destroyed_account_ids ||= Hash.new { |h,k| h[k] = [] }
+  end
+
+  # Test private kernel method through collection proxy using has_many.
+  def self.open
+    where('firm_name = ?', '37signals')
+  end
+
+  before_destroy do |account|
+    if account.firm
+      Account.destroyed_account_ids[account.firm.id] << account.id
+    end
+    true
+  end
+
+  validate :check_empty_credit_limit
+
+  protected
+
+  def check_empty_credit_limit
+    errors.add_on_empty "credit_limit"
+  end
+
+  private
+
+  def private_method
+    "Sir, yes sir!"
+  end
+end
diff --git a/activerecord/test/models/company_in_module.rb b/activerecord/test/models/company_in_module.rb
new file mode 100644
index 0000000000..dae102d12b
--- /dev/null
+++ b/activerecord/test/models/company_in_module.rb
@@ -0,0 +1,98 @@
+require 'active_support/core_ext/object/with_options'
+
+module MyApplication
+  module Business
+    class Company < ActiveRecord::Base
+    end
+
+    class Firm < Company
+      has_many :clients, -> { order("id") }, :dependent => :destroy
+      has_many :clients_sorted_desc, -> { order("id DESC") }, :class_name => "Client"
+      has_many :clients_of_firm, -> { order "id" }, :foreign_key => "client_of", :class_name => "Client"
+      has_many :clients_like_ms, -> { where("name = 'Microsoft'").order("id") }, :class_name => "Client"
+      has_one :account, :class_name => 'MyApplication::Billing::Account', :dependent => :destroy
+    end
+
+    class Client < Company
+      belongs_to :firm, :foreign_key => "client_of"
+      belongs_to :firm_with_other_name, :class_name => "Firm", :foreign_key => "client_of"
+
+      class Contact < ActiveRecord::Base; end
+    end
+
+    class Developer < ActiveRecord::Base
+      has_and_belongs_to_many :projects
+      validates_length_of :name, :within => (3..20)
+    end
+
+    class Project < ActiveRecord::Base
+      has_and_belongs_to_many :developers
+    end
+
+    module Prefixed
+      def self.table_name_prefix
+        'prefixed_'
+      end
+
+      class Company < ActiveRecord::Base
+      end
+
+      class Firm < Company
+        self.table_name = 'companies'
+      end
+
+      module Nested
+        class Company < ActiveRecord::Base
+        end
+      end
+    end
+
+    module Suffixed
+      def self.table_name_suffix
+        '_suffixed'
+      end
+
+      class Company < ActiveRecord::Base
+      end
+
+      class Firm < Company
+        self.table_name = 'companies'
+      end
+
+      module Nested
+        class Company < ActiveRecord::Base
+        end
+      end
+    end
+  end
+
+  module Billing
+    class Firm < ActiveRecord::Base
+      self.table_name = 'companies'
+    end
+
+    module Nested
+      class Firm < ActiveRecord::Base
+        self.table_name = 'companies'
+      end
+    end
+
+    class Account < ActiveRecord::Base
+      with_options(:foreign_key => :firm_id) do |i|
+        i.belongs_to :firm, :class_name => 'MyApplication::Business::Firm'
+        i.belongs_to :qualified_billing_firm, :class_name => 'MyApplication::Billing::Firm'
+        i.belongs_to :unqualified_billing_firm, :class_name => 'Firm'
+        i.belongs_to :nested_qualified_billing_firm, :class_name => 'MyApplication::Billing::Nested::Firm'
+        i.belongs_to :nested_unqualified_billing_firm, :class_name => 'Nested::Firm'
+      end
+
+      validate :check_empty_credit_limit
+
+      protected
+
+      def check_empty_credit_limit
+        errors.add_on_empty "credit_limit"
+      end
+    end
+  end
+end
diff --git a/activerecord/test/models/computer.rb b/activerecord/test/models/computer.rb
new file mode 100644
index 0000000000..cc8deb1b2b
--- /dev/null
+++ b/activerecord/test/models/computer.rb
@@ -0,0 +1,3 @@
+class Computer < ActiveRecord::Base
+  belongs_to :developer, :foreign_key=>'developer'
+end
diff --git a/activerecord/test/models/contact.rb b/activerecord/test/models/contact.rb
new file mode 100644
index 0000000000..3ea17c3abf
--- /dev/null
+++ b/activerecord/test/models/contact.rb
@@ -0,0 +1,41 @@
+module ContactFakeColumns
+  def self.extended(base)
+    base.class_eval do
+      establish_connection(:adapter => 'fake')
+
+      connection.tables = [table_name]
+      connection.primary_keys = {
+        table_name => 'id'
+      }
+
+      column :id,             :integer
+      column :name,           :string
+      column :age,            :integer
+      column :avatar,         :binary
+      column :created_at,     :datetime
+      column :awesome,        :boolean
+      column :preferences,    :string
+      column :alternative_id, :integer
+
+      serialize :preferences
+
+      belongs_to :alternative, :class_name => 'Contact'
+    end
+  end
+
+  # mock out self.columns so no pesky db is needed for these tests
+  def column(name, sql_type = nil, options = {})
+    connection.merge_column(table_name, name, sql_type, options)
+  end
+end
+
+class Contact < ActiveRecord::Base
+  extend ContactFakeColumns
+end
+
+class ContactSti < ActiveRecord::Base
+  extend ContactFakeColumns
+  column :type, :string
+
+  def type; 'ContactSti' end
+end
diff --git a/activerecord/test/models/contract.rb b/activerecord/test/models/contract.rb
new file mode 100644
index 0000000000..cdf7b267b5
--- /dev/null
+++ b/activerecord/test/models/contract.rb
@@ -0,0 +1,20 @@
+class Contract < ActiveRecord::Base
+  belongs_to :company
+  belongs_to :developer
+  belongs_to :firm, :foreign_key => 'company_id'
+
+  before_save :hi
+  after_save :bye
+
+  attr_accessor :hi_count, :bye_count
+
+  def hi
+    @hi_count ||= 0
+    @hi_count += 1
+  end
+
+  def bye
+    @bye_count ||= 0
+    @bye_count += 1
+  end
+end
diff --git a/activerecord/test/models/country.rb b/activerecord/test/models/country.rb
new file mode 100644
index 0000000000..7db9a4e731
--- /dev/null
+++ b/activerecord/test/models/country.rb
@@ -0,0 +1,7 @@
+class Country < ActiveRecord::Base
+
+  self.primary_key = :country_id
+
+  has_and_belongs_to_many :treaties
+
+end
diff --git a/activerecord/test/models/course.rb b/activerecord/test/models/course.rb
new file mode 100644
index 0000000000..f3d0e05ff7
--- /dev/null
+++ b/activerecord/test/models/course.rb
@@ -0,0 +1,6 @@
+require_dependency 'models/arunit2_model'
+
+class Course < ARUnit2Model
+  belongs_to :college
+  has_many :entrants
+end
diff --git a/activerecord/test/models/customer.rb b/activerecord/test/models/customer.rb
new file mode 100644
index 0000000000..7e8e82542f
--- /dev/null
+++ b/activerecord/test/models/customer.rb
@@ -0,0 +1,77 @@
+class Customer < ActiveRecord::Base
+  cattr_accessor :gps_conversion_was_run
+
+  composed_of :address, :mapping => [ %w(address_street street), %w(address_city city), %w(address_country country) ], :allow_nil => true
+  composed_of :balance, :class_name => "Money", :mapping => %w(balance amount), :converter => Proc.new { |balance| balance.to_money }
+  composed_of :gps_location, :allow_nil => true
+  composed_of :non_blank_gps_location, :class_name => "GpsLocation", :allow_nil => true, :mapping => %w(gps_location gps_location),
+              :converter => lambda { |gps| self.gps_conversion_was_run = true; gps.blank? ? nil : GpsLocation.new(gps)}
+  composed_of :fullname, :mapping => %w(name to_s), :constructor => Proc.new { |name| Fullname.parse(name) }, :converter => :parse
+end
+
+class Address
+  attr_reader :street, :city, :country
+
+  def initialize(street, city, country)
+    @street, @city, @country = street, city, country
+  end
+
+  def close_to?(other_address)
+    city == other_address.city && country == other_address.country
+  end
+
+  def ==(other)
+    other.is_a?(self.class) && other.street == street && other.city == city && other.country == country
+  end
+end
+
+class Money
+  attr_reader :amount, :currency
+
+  EXCHANGE_RATES = { "USD_TO_DKK" => 6, "DKK_TO_USD" => 0.6 }
+
+  def initialize(amount, currency = "USD")
+    @amount, @currency = amount, currency
+  end
+
+  def exchange_to(other_currency)
+    Money.new((amount * EXCHANGE_RATES["#{currency}_TO_#{other_currency}"]).floor, other_currency)
+  end
+end
+
+class GpsLocation
+  attr_reader :gps_location
+
+  def initialize(gps_location)
+    @gps_location = gps_location
+  end
+
+  def latitude
+    gps_location.split("x").first
+  end
+
+  def longitude
+    gps_location.split("x").last
+  end
+
+  def ==(other)
+    self.latitude == other.latitude && self.longitude == other.longitude
+  end
+end
+
+class Fullname
+  attr_reader :first, :last
+
+  def self.parse(str)
+    return nil unless str
+    new(*str.to_s.split)
+  end
+
+  def initialize(first, last = nil)
+    @first, @last = first, last
+  end
+
+  def to_s
+    "#{first} #{last.upcase}"
+  end
+end
diff --git a/activerecord/test/models/dashboard.rb b/activerecord/test/models/dashboard.rb
new file mode 100644
index 0000000000..1b3b54545f
--- /dev/null
+++ b/activerecord/test/models/dashboard.rb
@@ -0,0 +1,3 @@
+class Dashboard < ActiveRecord::Base
+  self.primary_key = :dashboard_id
+end
diff --git a/activerecord/test/models/default.rb b/activerecord/test/models/default.rb
new file mode 100644
index 0000000000..887e9cc999
--- /dev/null
+++ b/activerecord/test/models/default.rb
@@ -0,0 +1,2 @@
+class Default < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/department.rb b/activerecord/test/models/department.rb
new file mode 100644
index 0000000000..08004a0ed3
--- /dev/null
+++ b/activerecord/test/models/department.rb
@@ -0,0 +1,4 @@
+class Department < ActiveRecord::Base
+  has_many :chefs
+  belongs_to :hotel
+end
diff --git a/activerecord/test/models/developer.rb b/activerecord/test/models/developer.rb
new file mode 100644
index 0000000000..5bd2f00129
--- /dev/null
+++ b/activerecord/test/models/developer.rb
@@ -0,0 +1,248 @@
+require 'ostruct'
+
+module DeveloperProjectsAssociationExtension2
+  def find_least_recent
+    order("id ASC").first
+  end
+end
+
+class Developer < ActiveRecord::Base
+  has_and_belongs_to_many :projects do
+    def find_most_recent
+      order("id DESC").first
+    end
+  end
+
+  accepts_nested_attributes_for :projects
+
+  has_and_belongs_to_many :projects_extended_by_name,
+      -> { extending(DeveloperProjectsAssociationExtension) },
+      :class_name => "Project",
+      :join_table => "developers_projects",
+      :association_foreign_key => "project_id"
+
+  has_and_belongs_to_many :projects_extended_by_name_twice,
+      -> { extending(DeveloperProjectsAssociationExtension, DeveloperProjectsAssociationExtension2) },
+      :class_name => "Project",
+      :join_table => "developers_projects",
+      :association_foreign_key => "project_id"
+
+  has_and_belongs_to_many :projects_extended_by_name_and_block,
+      -> { extending(DeveloperProjectsAssociationExtension) },
+      :class_name => "Project",
+      :join_table => "developers_projects",
+      :association_foreign_key => "project_id" do
+        def find_least_recent
+          order("id ASC").first
+        end
+      end
+
+  has_and_belongs_to_many :special_projects, :join_table => 'developers_projects', :association_foreign_key => 'project_id'
+  has_and_belongs_to_many :sym_special_projects,
+                          :join_table => :developers_projects,
+                          :association_foreign_key => 'project_id',
+                          :class_name => 'SpecialProject'
+
+  has_many :audit_logs
+  has_many :contracts
+  has_many :firms, :through => :contracts, :source => :firm
+
+  scope :jamises, -> { where(:name => 'Jamis') }
+
+  validates_inclusion_of :salary, :in => 50000..200000
+  validates_length_of    :name, :within => 3..20
+
+  before_create do |developer|
+    developer.audit_logs.build :message => "Computer created"
+  end
+
+  def log=(message)
+    audit_logs.build :message => message
+  end
+
+  after_find :track_instance_count
+  cattr_accessor :instance_count
+
+  def track_instance_count
+    self.class.instance_count ||= 0
+    self.class.instance_count += 1
+  end
+  private :track_instance_count
+
+end
+
+class AuditLog < ActiveRecord::Base
+  belongs_to :developer, :validate => true
+  belongs_to :unvalidated_developer, :class_name => 'Developer'
+end
+
+class DeveloperWithBeforeDestroyRaise < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects, :join_table => 'developers_projects', :foreign_key => 'developer_id'
+  before_destroy :raise_if_projects_empty!
+
+  def raise_if_projects_empty!
+    raise if projects.empty?
+  end
+end
+
+class DeveloperWithSelect < ActiveRecord::Base
+  self.table_name = 'developers'
+  default_scope { select('name') }
+end
+
+class DeveloperWithIncludes < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_many :audit_logs, :foreign_key => :developer_id
+  default_scope { includes(:audit_logs) }
+end
+
+class DeveloperFilteredOnJoins < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects, -> { order('projects.id') }, :foreign_key => 'developer_id', :join_table => 'developers_projects'
+
+  def self.default_scope
+    joins(:projects).where(:projects => { :name => 'Active Controller' })
+  end
+end
+
+class DeveloperOrderedBySalary < ActiveRecord::Base
+  self.table_name = 'developers'
+  default_scope { order('salary DESC') }
+
+  scope :by_name, -> { order('name DESC') }
+end
+
+class DeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = 'developers'
+  default_scope { where("name = 'David'") }
+end
+
+class LazyLambdaDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = 'developers'
+  default_scope lambda { where(:name => 'David') }
+end
+
+class LazyBlockDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = 'developers'
+  default_scope { where(:name => 'David') }
+end
+
+class CallableDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = 'developers'
+  default_scope OpenStruct.new(:call => where(:name => 'David'))
+end
+
+class ClassMethodDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  def self.default_scope
+    where(:name => 'David')
+  end
+end
+
+class ClassMethodReferencingScopeDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = 'developers'
+  scope :david, -> { where(:name => 'David') }
+
+  def self.default_scope
+    david
+  end
+end
+
+class LazyBlockReferencingScopeDeveloperCalledDavid < ActiveRecord::Base
+  self.table_name = 'developers'
+  scope :david, -> { where(:name => 'David') }
+  default_scope { david }
+end
+
+class DeveloperCalledJamis < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  default_scope { where(:name => 'Jamis') }
+  scope :poor, -> { where('salary < 150000') }
+  scope :david, -> { where name: "David" }
+  scope :david2, -> { unscoped.where name: "David" }
+end
+
+class PoorDeveloperCalledJamis < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  default_scope -> { where(:name => 'Jamis', :salary => 50000) }
+end
+
+class InheritedPoorDeveloperCalledJamis < DeveloperCalledJamis
+  self.table_name = 'developers'
+
+  default_scope -> { where(:salary => 50000) }
+end
+
+class MultiplePoorDeveloperCalledJamis < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  default_scope -> { where(:name => 'Jamis') }
+  default_scope -> { where(:salary => 50000) }
+end
+
+module SalaryDefaultScope
+  extend ActiveSupport::Concern
+
+  included { default_scope { where(:salary => 50000) } }
+end
+
+class ModuleIncludedPoorDeveloperCalledJamis < DeveloperCalledJamis
+  self.table_name = 'developers'
+
+  include SalaryDefaultScope
+end
+
+class EagerDeveloperWithDefaultScope < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects, -> { order('projects.id') }, :foreign_key => 'developer_id', :join_table => 'developers_projects'
+
+  default_scope { includes(:projects) }
+end
+
+class EagerDeveloperWithClassMethodDefaultScope < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects, -> { order('projects.id') }, :foreign_key => 'developer_id', :join_table => 'developers_projects'
+
+  def self.default_scope
+    includes(:projects)
+  end
+end
+
+class EagerDeveloperWithLambdaDefaultScope < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects, -> { order('projects.id') }, :foreign_key => 'developer_id', :join_table => 'developers_projects'
+
+  default_scope lambda { includes(:projects) }
+end
+
+class EagerDeveloperWithBlockDefaultScope < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects, -> { order('projects.id') }, :foreign_key => 'developer_id', :join_table => 'developers_projects'
+
+  default_scope { includes(:projects) }
+end
+
+class EagerDeveloperWithCallableDefaultScope < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects, -> { order('projects.id') }, :foreign_key => 'developer_id', :join_table => 'developers_projects'
+
+  default_scope OpenStruct.new(:call => includes(:projects))
+end
+
+class ThreadsafeDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  def self.default_scope
+    sleep 0.05 if Thread.current[:long_default_scope]
+    limit(1)
+  end
+end
+
+class CachedDeveloper < ActiveRecord::Base
+  self.table_name = "developers"
+  self.cache_timestamp_format = :number
+end
diff --git a/activerecord/test/models/dog.rb b/activerecord/test/models/dog.rb
new file mode 100644
index 0000000000..b02b8447b8
--- /dev/null
+++ b/activerecord/test/models/dog.rb
@@ -0,0 +1,5 @@
+class Dog < ActiveRecord::Base
+  belongs_to :breeder, class_name: "DogLover", counter_cache: :bred_dogs_count
+  belongs_to :trainer, class_name: "DogLover", counter_cache: :trained_dogs_count
+  belongs_to :doglover, foreign_key: :dog_lover_id, class_name: "DogLover", counter_cache: true
+end
diff --git a/activerecord/test/models/dog_lover.rb b/activerecord/test/models/dog_lover.rb
new file mode 100644
index 0000000000..2c5be94aea
--- /dev/null
+++ b/activerecord/test/models/dog_lover.rb
@@ -0,0 +1,5 @@
+class DogLover < ActiveRecord::Base
+  has_many :trained_dogs, class_name: "Dog", foreign_key: :trainer_id, dependent: :destroy
+  has_many :bred_dogs, class_name: "Dog", foreign_key: :breeder_id
+  has_many :dogs
+end
diff --git a/activerecord/test/models/drink_designer.rb b/activerecord/test/models/drink_designer.rb
new file mode 100644
index 0000000000..2db968ef11
--- /dev/null
+++ b/activerecord/test/models/drink_designer.rb
@@ -0,0 +1,3 @@
+class DrinkDesigner < ActiveRecord::Base
+  has_one :chef, as: :employable
+end
diff --git a/activerecord/test/models/edge.rb b/activerecord/test/models/edge.rb
new file mode 100644
index 0000000000..55e0c31fcb
--- /dev/null
+++ b/activerecord/test/models/edge.rb
@@ -0,0 +1,5 @@
+# This class models an edge in a directed graph.
+class Edge < ActiveRecord::Base
+  belongs_to :source, :class_name => 'Vertex', :foreign_key => 'source_id'
+  belongs_to :sink,   :class_name => 'Vertex', :foreign_key => 'sink_id'
+end
diff --git a/activerecord/test/models/electron.rb b/activerecord/test/models/electron.rb
new file mode 100644
index 0000000000..6fc270673f
--- /dev/null
+++ b/activerecord/test/models/electron.rb
@@ -0,0 +1,5 @@
+class Electron < ActiveRecord::Base
+  belongs_to :molecule
+
+  validates_presence_of :name
+end
diff --git a/activerecord/test/models/engine.rb b/activerecord/test/models/engine.rb
new file mode 100644
index 0000000000..851ff8c22b
--- /dev/null
+++ b/activerecord/test/models/engine.rb
@@ -0,0 +1,4 @@
+class Engine < ActiveRecord::Base
+  belongs_to :my_car, :class_name => 'Car', :foreign_key => 'car_id',  :counter_cache => :engines_count
+end
+
diff --git a/activerecord/test/models/entrant.rb b/activerecord/test/models/entrant.rb
new file mode 100644
index 0000000000..4682ce48c8
--- /dev/null
+++ b/activerecord/test/models/entrant.rb
@@ -0,0 +1,3 @@
+class Entrant < ActiveRecord::Base
+  belongs_to :course
+end
diff --git a/activerecord/test/models/essay.rb b/activerecord/test/models/essay.rb
new file mode 100644
index 0000000000..ec4b982b5b
--- /dev/null
+++ b/activerecord/test/models/essay.rb
@@ -0,0 +1,5 @@
+class Essay < ActiveRecord::Base
+  belongs_to :writer, :primary_key => :name, :polymorphic => true
+  belongs_to :category, :primary_key => :name
+  has_one :owner, :primary_key => :name
+end
diff --git a/activerecord/test/models/event.rb b/activerecord/test/models/event.rb
new file mode 100644
index 0000000000..99fa0feeb7
--- /dev/null
+++ b/activerecord/test/models/event.rb
@@ -0,0 +1,3 @@
+class Event < ActiveRecord::Base
+  validates_uniqueness_of :title
+end
\ No newline at end of file
diff --git a/activerecord/test/models/eye.rb b/activerecord/test/models/eye.rb
new file mode 100644
index 0000000000..dc8ae2b3f6
--- /dev/null
+++ b/activerecord/test/models/eye.rb
@@ -0,0 +1,37 @@
+class Eye < ActiveRecord::Base
+  attr_reader :after_create_callbacks_stack
+  attr_reader :after_update_callbacks_stack
+  attr_reader :after_save_callbacks_stack
+
+  # Callbacks configured before the ones has_one sets up.
+  after_create :trace_after_create
+  after_update :trace_after_update
+  after_save   :trace_after_save
+
+  has_one :iris
+  accepts_nested_attributes_for :iris
+
+  # Callbacks configured after the ones has_one sets up.
+  after_create :trace_after_create2
+  after_update :trace_after_update2
+  after_save   :trace_after_save2
+  
+  def trace_after_create
+    (@after_create_callbacks_stack ||= []) << !iris.persisted?
+  end
+  alias trace_after_create2 trace_after_create
+
+  def trace_after_update
+    (@after_update_callbacks_stack ||= []) << iris.changed?
+  end
+  alias trace_after_update2 trace_after_update
+
+  def trace_after_save
+    (@after_save_callbacks_stack ||= []) << iris.changed?
+  end
+  alias trace_after_save2 trace_after_save
+end
+
+class Iris < ActiveRecord::Base
+  belongs_to :eye
+end
diff --git a/activerecord/test/models/face.rb b/activerecord/test/models/face.rb
new file mode 100644
index 0000000000..91e46f83e5
--- /dev/null
+++ b/activerecord/test/models/face.rb
@@ -0,0 +1,9 @@
+class Face < ActiveRecord::Base
+  belongs_to :man, :inverse_of => :face
+  belongs_to :polymorphic_man, :polymorphic => true, :inverse_of => :polymorphic_face
+  # Oracle identifier lengh is limited to 30 bytes or less, `polymorphic` renamed `poly`
+  belongs_to :poly_man_without_inverse, :polymorphic => true
+  # These is a "broken" inverse_of for the purposes of testing
+  belongs_to :horrible_man, :class_name => 'Man', :inverse_of => :horrible_face
+  belongs_to :horrible_polymorphic_man, :polymorphic => true, :inverse_of => :horrible_polymorphic_face
+end
diff --git a/activerecord/test/models/friendship.rb b/activerecord/test/models/friendship.rb
new file mode 100644
index 0000000000..4b411ca8e0
--- /dev/null
+++ b/activerecord/test/models/friendship.rb
@@ -0,0 +1,6 @@
+class Friendship < ActiveRecord::Base
+  belongs_to :friend, class_name: 'Person'
+  # friend_too exists to test a bug, and probably shouldn't be used elsewhere
+  belongs_to :friend_too, foreign_key: 'friend_id', class_name: 'Person', counter_cache: :friends_too_count
+  belongs_to :follower, class_name: 'Person'
+end
diff --git a/activerecord/test/models/guid.rb b/activerecord/test/models/guid.rb
new file mode 100644
index 0000000000..9208dc28fa
--- /dev/null
+++ b/activerecord/test/models/guid.rb
@@ -0,0 +1,2 @@
+class Guid < ActiveRecord::Base
+end
\ No newline at end of file
diff --git a/activerecord/test/models/hotel.rb b/activerecord/test/models/hotel.rb
new file mode 100644
index 0000000000..b352cd22f3
--- /dev/null
+++ b/activerecord/test/models/hotel.rb
@@ -0,0 +1,6 @@
+class Hotel < ActiveRecord::Base
+  has_many :departments
+  has_many :chefs, through: :departments
+  has_many :cake_designers, source_type: 'CakeDesigner', source: :employable, through: :chefs
+  has_many :drink_designers, source_type: 'DrinkDesigner', source: :employable, through: :chefs
+end
diff --git a/activerecord/test/models/interest.rb b/activerecord/test/models/interest.rb
new file mode 100644
index 0000000000..d5d9226204
--- /dev/null
+++ b/activerecord/test/models/interest.rb
@@ -0,0 +1,5 @@
+class Interest < ActiveRecord::Base
+  belongs_to :man, :inverse_of => :interests
+  belongs_to :polymorphic_man, :polymorphic => true, :inverse_of => :polymorphic_interests
+  belongs_to :zine, :inverse_of => :interests
+end
diff --git a/activerecord/test/models/invoice.rb b/activerecord/test/models/invoice.rb
new file mode 100644
index 0000000000..fc6ef0230e
--- /dev/null
+++ b/activerecord/test/models/invoice.rb
@@ -0,0 +1,4 @@
+class Invoice < ActiveRecord::Base
+  has_many :line_items, :autosave => true
+  before_save {|record| record.balance = record.line_items.map(&:amount).sum }
+end
diff --git a/activerecord/test/models/item.rb b/activerecord/test/models/item.rb
new file mode 100644
index 0000000000..c2571dd7fb
--- /dev/null
+++ b/activerecord/test/models/item.rb
@@ -0,0 +1,7 @@
+class AbstractItem < ActiveRecord::Base
+  self.abstract_class = true
+  has_one :tagging, :as => :taggable
+end
+
+class Item < AbstractItem
+end
diff --git a/activerecord/test/models/job.rb b/activerecord/test/models/job.rb
new file mode 100644
index 0000000000..f7b0e787b1
--- /dev/null
+++ b/activerecord/test/models/job.rb
@@ -0,0 +1,7 @@
+class Job < ActiveRecord::Base
+  has_many :references
+  has_many :people, :through => :references
+  belongs_to :ideal_reference, :class_name => 'Reference'
+
+  has_many :agents, :through => :people
+end
diff --git a/activerecord/test/models/joke.rb b/activerecord/test/models/joke.rb
new file mode 100644
index 0000000000..edda4655dc
--- /dev/null
+++ b/activerecord/test/models/joke.rb
@@ -0,0 +1,7 @@
+class Joke < ActiveRecord::Base
+  self.table_name = 'funny_jokes'
+end
+
+class GoodJoke < ActiveRecord::Base
+  self.table_name = 'funny_jokes'
+end
diff --git a/activerecord/test/models/keyboard.rb b/activerecord/test/models/keyboard.rb
new file mode 100644
index 0000000000..39347e274e
--- /dev/null
+++ b/activerecord/test/models/keyboard.rb
@@ -0,0 +1,3 @@
+class Keyboard < ActiveRecord::Base
+  self.primary_key = 'key_number'
+end
diff --git a/activerecord/test/models/legacy_thing.rb b/activerecord/test/models/legacy_thing.rb
new file mode 100644
index 0000000000..eead181a0e
--- /dev/null
+++ b/activerecord/test/models/legacy_thing.rb
@@ -0,0 +1,3 @@
+class LegacyThing < ActiveRecord::Base
+  self.locking_column = :version
+end
diff --git a/activerecord/test/models/lesson.rb b/activerecord/test/models/lesson.rb
new file mode 100644
index 0000000000..4c88153068
--- /dev/null
+++ b/activerecord/test/models/lesson.rb
@@ -0,0 +1,11 @@
+class LessonError < Exception
+end
+
+class Lesson < ActiveRecord::Base
+  has_and_belongs_to_many :students
+  before_destroy :ensure_no_students
+
+  def ensure_no_students
+    raise LessonError unless students.empty?
+  end
+end
diff --git a/activerecord/test/models/line_item.rb b/activerecord/test/models/line_item.rb
new file mode 100644
index 0000000000..0dd921a300
--- /dev/null
+++ b/activerecord/test/models/line_item.rb
@@ -0,0 +1,3 @@
+class LineItem < ActiveRecord::Base
+  belongs_to :invoice, :touch => true
+end
diff --git a/activerecord/test/models/liquid.rb b/activerecord/test/models/liquid.rb
new file mode 100644
index 0000000000..69d4d7df1a
--- /dev/null
+++ b/activerecord/test/models/liquid.rb
@@ -0,0 +1,4 @@
+class Liquid < ActiveRecord::Base
+  self.table_name = :liquid
+  has_many :molecules, -> { distinct }
+end
diff --git a/activerecord/test/models/man.rb b/activerecord/test/models/man.rb
new file mode 100644
index 0000000000..4fbb6b226b
--- /dev/null
+++ b/activerecord/test/models/man.rb
@@ -0,0 +1,11 @@
+class Man < ActiveRecord::Base
+  has_one :face, :inverse_of => :man
+  has_one :polymorphic_face, :class_name => 'Face', :as => :polymorphic_man, :inverse_of => :polymorphic_man
+  has_one :polymorphic_face_without_inverse, :class_name => 'Face', :as => :poly_man_without_inverse
+  has_many :interests, :inverse_of => :man
+  has_many :polymorphic_interests, :class_name => 'Interest', :as => :polymorphic_man, :inverse_of => :polymorphic_man
+  # These are "broken" inverse_of associations for the purposes of testing
+  has_one :dirty_face, :class_name => 'Face', :inverse_of => :dirty_man
+  has_many :secret_interests, :class_name => 'Interest', :inverse_of => :secret_man
+  has_one :mixed_case_monkey
+end
diff --git a/activerecord/test/models/matey.rb b/activerecord/test/models/matey.rb
new file mode 100644
index 0000000000..47b0baa974
--- /dev/null
+++ b/activerecord/test/models/matey.rb
@@ -0,0 +1,4 @@
+class Matey < ActiveRecord::Base
+  belongs_to :pirate
+  belongs_to :target, :class_name => 'Pirate'
+end
diff --git a/activerecord/test/models/member.rb b/activerecord/test/models/member.rb
new file mode 100644
index 0000000000..72095f9236
--- /dev/null
+++ b/activerecord/test/models/member.rb
@@ -0,0 +1,35 @@
+class Member < ActiveRecord::Base
+  has_one :current_membership
+  has_one :selected_membership
+  has_one :membership
+  has_one :club, :through => :current_membership
+  has_one :selected_club, :through => :selected_membership, :source => :club
+  has_one :favourite_club, -> { where "memberships.favourite = ?", true }, :through => :membership, :source => :club
+  has_one :hairy_club, -> { where :clubs => {:name => "Moustache and Eyebrow Fancier Club"} }, :through => :membership, :source => :club
+  has_one :sponsor, :as => :sponsorable
+  has_one :sponsor_club, :through => :sponsor
+  has_one :member_detail, :inverse_of => false
+  has_one :organization, :through => :member_detail
+  belongs_to :member_type
+
+  has_many :nested_member_types, :through => :member_detail, :source => :member_type
+  has_one :nested_member_type, :through => :member_detail, :source => :member_type
+
+  has_many :nested_sponsors, :through => :sponsor_club, :source => :sponsor
+  has_one :nested_sponsor, :through => :sponsor_club, :source => :sponsor
+
+  has_many :organization_member_details, :through => :member_detail
+  has_many :organization_member_details_2, :through => :organization, :source => :member_details
+
+  has_one :club_category, :through => :club, :source => :category
+
+  has_many :current_memberships, -> { where :favourite => true }
+  has_many :clubs, :through => :current_memberships
+
+  has_one :club_through_many, :through => :current_memberships, :source => :club
+end
+
+class SelfMember < ActiveRecord::Base
+  self.table_name = "members"
+  has_and_belongs_to_many :friends, :class_name => "SelfMember", :join_table => "member_friends"
+end
diff --git a/activerecord/test/models/member_detail.rb b/activerecord/test/models/member_detail.rb
new file mode 100644
index 0000000000..9d253aa126
--- /dev/null
+++ b/activerecord/test/models/member_detail.rb
@@ -0,0 +1,7 @@
+class MemberDetail < ActiveRecord::Base
+  belongs_to :member, :inverse_of => false
+  belongs_to :organization
+  has_one :member_type, :through => :member
+
+  has_many :organization_member_details, :through => :organization, :source => :member_details
+end
diff --git a/activerecord/test/models/member_type.rb b/activerecord/test/models/member_type.rb
new file mode 100644
index 0000000000..a13561c72a
--- /dev/null
+++ b/activerecord/test/models/member_type.rb
@@ -0,0 +1,3 @@
+class MemberType < ActiveRecord::Base
+  has_many :members
+end
diff --git a/activerecord/test/models/membership.rb b/activerecord/test/models/membership.rb
new file mode 100644
index 0000000000..df7167ee93
--- /dev/null
+++ b/activerecord/test/models/membership.rb
@@ -0,0 +1,20 @@
+class Membership < ActiveRecord::Base
+  belongs_to :member
+  belongs_to :club
+end
+
+class CurrentMembership < Membership
+  belongs_to :member
+  belongs_to :club
+end
+
+class SuperMembership < Membership
+  belongs_to :member, -> { order('members.id DESC') }
+  belongs_to :club
+end
+
+class SelectedMembership < Membership
+  def self.default_scope
+    select("'1' as foo")
+  end
+end
diff --git a/activerecord/test/models/minimalistic.rb b/activerecord/test/models/minimalistic.rb
new file mode 100644
index 0000000000..2e3f8e081a
--- /dev/null
+++ b/activerecord/test/models/minimalistic.rb
@@ -0,0 +1,2 @@
+class Minimalistic < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/minivan.rb b/activerecord/test/models/minivan.rb
new file mode 100644
index 0000000000..4fe79720ad
--- /dev/null
+++ b/activerecord/test/models/minivan.rb
@@ -0,0 +1,9 @@
+class Minivan < ActiveRecord::Base
+  self.primary_key = :minivan_id
+
+  belongs_to :speedometer
+  has_one :dashboard, :through => :speedometer
+
+  attr_readonly :color
+
+end
diff --git a/activerecord/test/models/mixed_case_monkey.rb b/activerecord/test/models/mixed_case_monkey.rb
new file mode 100644
index 0000000000..1c35006665
--- /dev/null
+++ b/activerecord/test/models/mixed_case_monkey.rb
@@ -0,0 +1,3 @@
+class MixedCaseMonkey < ActiveRecord::Base
+  belongs_to :man
+end
diff --git a/activerecord/test/models/molecule.rb b/activerecord/test/models/molecule.rb
new file mode 100644
index 0000000000..26870c8f88
--- /dev/null
+++ b/activerecord/test/models/molecule.rb
@@ -0,0 +1,6 @@
+class Molecule < ActiveRecord::Base
+  belongs_to :liquid
+  has_many :electrons
+
+  accepts_nested_attributes_for :electrons
+end
diff --git a/activerecord/test/models/movie.rb b/activerecord/test/models/movie.rb
new file mode 100644
index 0000000000..0302abad1e
--- /dev/null
+++ b/activerecord/test/models/movie.rb
@@ -0,0 +1,5 @@
+class Movie < ActiveRecord::Base
+  self.primary_key = "movieid"
+
+  validates_presence_of :name
+end
diff --git a/activerecord/test/models/order.rb b/activerecord/test/models/order.rb
new file mode 100644
index 0000000000..e838c0b70d
--- /dev/null
+++ b/activerecord/test/models/order.rb
@@ -0,0 +1,4 @@
+class Order < ActiveRecord::Base
+  belongs_to :billing, :class_name => 'Customer', :foreign_key => 'billing_customer_id'
+  belongs_to :shipping, :class_name => 'Customer', :foreign_key => 'shipping_customer_id'
+end
diff --git a/activerecord/test/models/organization.rb b/activerecord/test/models/organization.rb
new file mode 100644
index 0000000000..72e7bade68
--- /dev/null
+++ b/activerecord/test/models/organization.rb
@@ -0,0 +1,12 @@
+class Organization < ActiveRecord::Base
+  has_many :member_details
+  has_many :members, :through => :member_details
+
+  has_many :authors, :primary_key => :name
+  has_many :author_essay_categories, :through => :authors, :source => :essay_categories
+
+  has_one :author, :primary_key => :name
+  has_one :author_owned_essay_category, :through => :author, :source => :owned_essay_category
+
+  scope :clubs, -> { from('clubs') }
+end
diff --git a/activerecord/test/models/owner.rb b/activerecord/test/models/owner.rb
new file mode 100644
index 0000000000..2e3a9a3681
--- /dev/null
+++ b/activerecord/test/models/owner.rb
@@ -0,0 +1,34 @@
+class Owner < ActiveRecord::Base
+  self.primary_key = :owner_id
+  has_many :pets, -> { order 'pets.name desc' }
+  has_many :toys, :through => :pets
+
+  belongs_to :last_pet, class_name: 'Pet'
+  scope :including_last_pet, -> {
+    select(%q[
+      owners.*, (
+        select p.pet_id from pets p
+        where p.owner_id = owners.owner_id
+        order by p.name desc
+        limit 1
+      ) as last_pet_id
+    ]).includes(:last_pet)
+  }
+
+  after_commit :execute_blocks
+
+  def blocks
+    @blocks ||= []
+  end
+
+  def on_after_commit(&block)
+    blocks << block
+  end
+
+  def execute_blocks
+    blocks.each do |block|
+      block.call(self)
+    end
+    @blocks = []
+  end
+end
diff --git a/activerecord/test/models/parrot.rb b/activerecord/test/models/parrot.rb
new file mode 100644
index 0000000000..e76e83f314
--- /dev/null
+++ b/activerecord/test/models/parrot.rb
@@ -0,0 +1,29 @@
+class Parrot < ActiveRecord::Base
+  self.inheritance_column = :parrot_sti_class
+
+  has_and_belongs_to_many :pirates
+  has_and_belongs_to_many :treasures
+  has_many :loots, :as => :looter
+  alias_attribute :title, :name
+
+  validates_presence_of :name
+
+  attr_accessor :cancel_save_from_callback
+  before_save :cancel_save_callback_method, :if => :cancel_save_from_callback
+  def cancel_save_callback_method
+    false
+  end
+end
+
+class LiveParrot < Parrot
+end
+
+class DeadParrot < Parrot
+  belongs_to :killer, :class_name => 'Pirate'
+end
+
+class FunkyParrot < Parrot
+  before_destroy do
+    raise "before_destroy was called"
+  end
+end
diff --git a/activerecord/test/models/person.rb b/activerecord/test/models/person.rb
new file mode 100644
index 0000000000..c7e54e7b63
--- /dev/null
+++ b/activerecord/test/models/person.rb
@@ -0,0 +1,141 @@
+class Person < ActiveRecord::Base
+  has_many :readers
+  has_many :secure_readers
+  has_one  :reader
+
+  has_many :posts, :through => :readers
+  has_many :secure_posts, :through => :secure_readers
+  has_many :posts_with_no_comments, -> { includes(:comments).where('comments.id is null').references(:comments) },
+                                    :through => :readers, :source => :post
+
+  has_many :friendships, foreign_key: 'friend_id'
+  # friends_too exists to test a bug, and probably shouldn't be used elsewhere
+  has_many :friends_too, foreign_key: 'friend_id', class_name: 'Friendship'
+  has_many :followers, through: :friendships
+
+  has_many :references
+  has_many :bad_references
+  has_many :fixed_bad_references, -> { where :favourite => true }, :class_name => 'BadReference'
+  has_one  :favourite_reference, -> { where 'favourite=?', true }, :class_name => 'Reference'
+  has_many :posts_with_comments_sorted_by_comment_id, -> { includes(:comments).order('comments.id') }, :through => :readers, :source => :post
+  has_many :first_posts, -> { where(id: [1, 2]) }, through: :readers
+
+  has_many :jobs, :through => :references
+  has_many :jobs_with_dependent_destroy,    :source => :job, :through => :references, :dependent => :destroy
+  has_many :jobs_with_dependent_delete_all, :source => :job, :through => :references, :dependent => :delete_all
+  has_many :jobs_with_dependent_nullify,    :source => :job, :through => :references, :dependent => :nullify
+
+  belongs_to :primary_contact, :class_name => 'Person'
+  has_many :agents, :class_name => 'Person', :foreign_key => 'primary_contact_id'
+  has_many :agents_of_agents, :through => :agents, :source => :agents
+  belongs_to :number1_fan, :class_name => 'Person'
+
+  has_many :agents_posts,         :through => :agents,       :source => :posts
+  has_many :agents_posts_authors, :through => :agents_posts, :source => :author
+  has_many :essays, primary_key: "first_name", foreign_key: "writer_id"
+
+  scope :males,   -> { where(:gender => 'M') }
+  scope :females, -> { where(:gender => 'F') }
+end
+
+class PersonWithDependentDestroyJobs < ActiveRecord::Base
+  self.table_name = 'people'
+
+  has_many :references, :foreign_key => :person_id
+  has_many :jobs, :source => :job, :through => :references, :dependent => :destroy
+end
+
+class PersonWithDependentDeleteAllJobs < ActiveRecord::Base
+  self.table_name = 'people'
+
+  has_many :references, :foreign_key => :person_id
+  has_many :jobs, :source => :job, :through => :references, :dependent => :delete_all
+end
+
+class PersonWithDependentNullifyJobs < ActiveRecord::Base
+  self.table_name = 'people'
+
+  has_many :references, :foreign_key => :person_id
+  has_many :jobs, :source => :job, :through => :references, :dependent => :nullify
+end
+
+
+class LoosePerson < ActiveRecord::Base
+  self.table_name = 'people'
+  self.abstract_class = true
+
+  has_one    :best_friend,    :class_name => 'LoosePerson', :foreign_key => :best_friend_id
+  belongs_to :best_friend_of, :class_name => 'LoosePerson', :foreign_key => :best_friend_of_id
+  has_many   :best_friends,   :class_name => 'LoosePerson', :foreign_key => :best_friend_id
+
+  accepts_nested_attributes_for :best_friend, :best_friend_of, :best_friends
+end
+
+class LooseDescendant < LoosePerson; end
+
+class TightPerson < ActiveRecord::Base
+  self.table_name = 'people'
+
+  has_one    :best_friend,    :class_name => 'TightPerson', :foreign_key => :best_friend_id
+  belongs_to :best_friend_of, :class_name => 'TightPerson', :foreign_key => :best_friend_of_id
+  has_many   :best_friends,   :class_name => 'TightPerson', :foreign_key => :best_friend_id
+
+  accepts_nested_attributes_for :best_friend, :best_friend_of, :best_friends
+end
+
+class TightDescendant < TightPerson; end
+
+class RichPerson < ActiveRecord::Base
+  self.table_name = 'people'
+
+  has_and_belongs_to_many :treasures, :join_table => 'peoples_treasures'
+
+  before_validation :run_before_create, on: :create
+  before_validation :run_before_validation
+
+  private
+
+  def run_before_create
+    self.first_name = first_name.to_s + 'run_before_create'
+  end
+
+  def run_before_validation
+    self.first_name = first_name.to_s + 'run_before_validation'
+  end
+end
+
+class NestedPerson < ActiveRecord::Base
+  self.table_name = 'people'
+
+  has_one :best_friend, :class_name => 'NestedPerson', :foreign_key => :best_friend_id
+  accepts_nested_attributes_for :best_friend, :update_only => true
+
+  def comments=(new_comments)
+    raise RuntimeError
+  end
+
+  def best_friend_first_name=(new_name)
+    assign_attributes({ :best_friend_attributes => { :first_name => new_name } })
+  end
+end
+
+class Insure
+  INSURES = %W{life annuality}
+
+  def self.load mask
+    INSURES.select do |insure|
+      (1 << INSURES.index(insure)) & mask.to_i > 0
+    end
+  end
+
+  def self.dump insures
+    numbers = insures.map { |insure| INSURES.index(insure) }
+    numbers.inject(0) { |sum, n| sum + (1 << n) }
+  end
+end
+
+class SerializedPerson < ActiveRecord::Base
+  self.table_name = 'people'
+
+  serialize :insures, Insure
+end
diff --git a/activerecord/test/models/pet.rb b/activerecord/test/models/pet.rb
new file mode 100644
index 0000000000..f7970d7aab
--- /dev/null
+++ b/activerecord/test/models/pet.rb
@@ -0,0 +1,15 @@
+class Pet < ActiveRecord::Base
+  attr_accessor :current_user
+
+  self.primary_key = :pet_id
+  belongs_to :owner, :touch => true
+  has_many :toys
+
+  class << self
+    attr_accessor :after_destroy_output
+  end
+
+  after_destroy do |record|
+    Pet.after_destroy_output = record.current_user
+  end
+end
diff --git a/activerecord/test/models/pirate.rb b/activerecord/test/models/pirate.rb
new file mode 100644
index 0000000000..90a3c3ecee
--- /dev/null
+++ b/activerecord/test/models/pirate.rb
@@ -0,0 +1,92 @@
+class Pirate < ActiveRecord::Base
+  belongs_to :parrot, :validate => true
+  belongs_to :non_validated_parrot, :class_name => 'Parrot'
+  has_and_belongs_to_many :parrots, -> { order('parrots.id ASC') }, :validate => true
+  has_and_belongs_to_many :non_validated_parrots, :class_name => 'Parrot'
+  has_and_belongs_to_many :parrots_with_method_callbacks, :class_name => "Parrot",
+    :before_add    => :log_before_add,
+    :after_add     => :log_after_add,
+    :before_remove => :log_before_remove,
+    :after_remove  => :log_after_remove
+  has_and_belongs_to_many :parrots_with_proc_callbacks, :class_name => "Parrot",
+    :before_add    => proc {|p,pa| p.ship_log << "before_adding_proc_parrot_#{pa.id || '<new>'}"},
+    :after_add     => proc {|p,pa| p.ship_log << "after_adding_proc_parrot_#{pa.id || '<new>'}"},
+    :before_remove => proc {|p,pa| p.ship_log << "before_removing_proc_parrot_#{pa.id}"},
+    :after_remove  => proc {|p,pa| p.ship_log << "after_removing_proc_parrot_#{pa.id}"}
+  has_and_belongs_to_many :autosaved_parrots, class_name: "Parrot", autosave: true
+
+  has_many :treasures, :as => :looter
+  has_many :treasure_estimates, :through => :treasures, :source => :price_estimates
+
+  has_one :ship
+  has_one :update_only_ship, :class_name => 'Ship'
+  has_one :non_validated_ship, :class_name => 'Ship'
+  has_many :birds, -> { order('birds.id ASC') }
+  has_many :birds_with_method_callbacks, :class_name => "Bird",
+    :before_add    => :log_before_add,
+    :after_add     => :log_after_add,
+    :before_remove => :log_before_remove,
+    :after_remove  => :log_after_remove
+  has_many :birds_with_proc_callbacks, :class_name => "Bird",
+    :before_add     => proc {|p,b| p.ship_log << "before_adding_proc_bird_#{b.id || '<new>'}"},
+    :after_add      => proc {|p,b| p.ship_log << "after_adding_proc_bird_#{b.id || '<new>'}"},
+    :before_remove  => proc {|p,b| p.ship_log << "before_removing_proc_bird_#{b.id}"},
+    :after_remove   => proc {|p,b| p.ship_log << "after_removing_proc_bird_#{b.id}"}
+  has_many :birds_with_reject_all_blank, :class_name => "Bird"
+
+  has_one :foo_bulb, -> { where :name => 'foo' }, :foreign_key => :car_id, :class_name => "Bulb"
+
+  accepts_nested_attributes_for :parrots, :birds, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? }
+  accepts_nested_attributes_for :ship, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? }
+  accepts_nested_attributes_for :update_only_ship, :update_only => true
+  accepts_nested_attributes_for :parrots_with_method_callbacks, :parrots_with_proc_callbacks,
+    :birds_with_method_callbacks, :birds_with_proc_callbacks, :allow_destroy => true
+  accepts_nested_attributes_for :birds_with_reject_all_blank, :reject_if => :all_blank
+
+  validates_presence_of :catchphrase
+
+  def ship_log
+    @ship_log ||= []
+  end
+
+  def reject_empty_ships_on_create(attributes)
+    attributes.delete('_reject_me_if_new').present? && !persisted?
+  end
+
+  attr_accessor :cancel_save_from_callback, :parrots_limit
+  before_save :cancel_save_callback_method, :if => :cancel_save_from_callback
+  def cancel_save_callback_method
+    false
+  end
+
+  private
+    def log_before_add(record)
+      log(record, "before_adding_method")
+    end
+
+    def log_after_add(record)
+      log(record, "after_adding_method")
+    end
+
+    def log_before_remove(record)
+      log(record, "before_removing_method")
+    end
+
+    def log_after_remove(record)
+      log(record, "after_removing_method")
+    end
+
+    def log(record, callback)
+      ship_log << "#{callback}_#{record.class.name.downcase}_#{record.id || '<new>'}"
+    end
+end
+
+class DestructivePirate < Pirate
+  has_one :dependent_ship, :class_name => 'Ship', :foreign_key => :pirate_id, :dependent => :destroy
+end
+
+class FamousPirate < ActiveRecord::Base
+  self.table_name = 'pirates'
+  has_many :famous_ships
+  validates_presence_of :catchphrase, on: :conference
+end
\ No newline at end of file
diff --git a/activerecord/test/models/possession.rb b/activerecord/test/models/possession.rb
new file mode 100644
index 0000000000..ddf759113b
--- /dev/null
+++ b/activerecord/test/models/possession.rb
@@ -0,0 +1,3 @@
+class Possession < ActiveRecord::Base
+  self.table_name = 'having'
+end
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
new file mode 100644
index 0000000000..a29858213b
--- /dev/null
+++ b/activerecord/test/models/post.rb
@@ -0,0 +1,219 @@
+class Post < ActiveRecord::Base
+  class CategoryPost < ActiveRecord::Base
+    self.table_name = "categories_posts"
+    belongs_to :category
+    belongs_to :post
+  end
+
+  module NamedExtension
+    def author
+      'lifo'
+    end
+  end
+
+  module NamedExtension2
+    def greeting
+      "hello"
+    end
+  end
+
+  scope :containing_the_letter_a, -> { where("body LIKE '%a%'") }
+  scope :ranked_by_comments,      -> { order("comments_count DESC") }
+
+  scope :limit_by, lambda {|l| limit(l) }
+
+  belongs_to :author
+
+  belongs_to :author_with_posts, -> { includes(:posts) }, :class_name => "Author", :foreign_key => :author_id
+  belongs_to :author_with_address, -> { includes(:author_address) }, :class_name => "Author", :foreign_key => :author_id
+
+  def first_comment
+    super.body
+  end
+  has_one :first_comment, -> { order('id ASC') }, :class_name => 'Comment'
+  has_one :last_comment, -> { order('id desc') }, :class_name => 'Comment'
+
+  scope :with_special_comments, -> { joins(:comments).where(:comments => {:type => 'SpecialComment'}) }
+  scope :with_very_special_comments, -> { joins(:comments).where(:comments => {:type => 'VerySpecialComment'}) }
+  scope :with_post, ->(post_id) { joins(:comments).where(:comments => { :post_id => post_id }) }
+
+  scope :with_comments, -> { preload(:comments) }
+  scope :with_tags, -> { preload(:taggings) }
+
+  scope :tagged_with, ->(id) { joins(:taggings).where(taggings: { tag_id: id }) }
+
+  has_many   :comments do
+    def find_most_recent
+      order("id DESC").first
+    end
+
+    def newest
+      created.last
+    end
+
+    def the_association
+      proxy_association
+    end
+  end
+
+  has_many :comments_with_extend, extend: NamedExtension, class_name: "Comment", foreign_key: "post_id" do
+    def greeting
+      "hello"
+    end
+  end
+
+  has_many :comments_with_extend_2, extend: [NamedExtension, NamedExtension2], class_name: "Comment", foreign_key: "post_id"
+
+  has_many :author_favorites, :through => :author
+  has_many :author_categorizations, :through => :author, :source => :categorizations
+  has_many :author_addresses, :through => :author
+  has_many :author_address_extra_with_address,
+    through: :author_with_address,
+    source: :author_address_extra
+
+  has_many :comments_with_interpolated_conditions,
+    ->(p) { where "#{"#{p.aliased_table_name}." rescue ""}body = ?", 'Thank you for the welcome' },
+    :class_name => 'Comment'
+
+  has_one  :very_special_comment
+  has_one  :very_special_comment_with_post, -> { includes(:post) }, :class_name => "VerySpecialComment"
+  has_many :special_comments
+  has_many :nonexistant_comments, -> { where 'comments.id < 0' }, :class_name => 'Comment'
+
+  has_many :special_comments_ratings, :through => :special_comments, :source => :ratings
+  has_many :special_comments_ratings_taggings, :through => :special_comments_ratings, :source => :taggings
+
+  has_many :category_posts, :class_name => 'CategoryPost'
+  has_many :scategories, through: :category_posts, source: :category
+  has_and_belongs_to_many :categories
+  has_and_belongs_to_many :special_categories, :join_table => "categories_posts", :association_foreign_key => 'category_id'
+
+  has_many :taggings, :as => :taggable, :counter_cache => :tags_count
+  has_many :tags, :through => :taggings do
+    def add_joins_and_select
+      select('tags.*, authors.id as author_id')
+        .joins('left outer join posts on taggings.taggable_id = posts.id left outer join authors on posts.author_id = authors.id')
+        .to_a
+    end
+  end
+
+  has_many :taggings_with_delete_all, :class_name => 'Tagging', :as => :taggable, :dependent => :delete_all
+  has_many :taggings_with_destroy, :class_name => 'Tagging', :as => :taggable, :dependent => :destroy
+
+  has_many :tags_with_destroy, :through => :taggings, :source => :tag, :dependent => :destroy
+  has_many :tags_with_nullify, :through => :taggings, :source => :tag, :dependent => :nullify
+
+  has_many :misc_tags, -> { where :tags => { :name => 'Misc' } }, :through => :taggings, :source => :tag
+  has_many :funky_tags, :through => :taggings, :source => :tag
+  has_many :super_tags, :through => :taggings
+  has_many :tags_with_primary_key, :through => :taggings, :source => :tag_with_primary_key
+  has_one :tagging, :as => :taggable
+
+  has_many :first_taggings, -> { where :taggings => { :comment => 'first' } }, :as => :taggable, :class_name => 'Tagging'
+  has_many :first_blue_tags, -> { where :tags => { :name => 'Blue' } }, :through => :first_taggings, :source => :tag
+
+  has_many :first_blue_tags_2, -> { where :taggings => { :comment => 'first' } }, :through => :taggings, :source => :blue_tag
+
+  has_many :invalid_taggings, -> { where 'taggings.id < 0' }, :as => :taggable, :class_name => "Tagging"
+  has_many :invalid_tags, :through => :invalid_taggings, :source => :tag
+
+  has_many :categorizations, :foreign_key => :category_id
+  has_many :authors, :through => :categorizations
+
+  has_many :categorizations_using_author_id, :primary_key => :author_id, :foreign_key => :post_id, :class_name => 'Categorization'
+  has_many :authors_using_author_id, :through => :categorizations_using_author_id, :source => :author
+
+  has_many :taggings_using_author_id, :primary_key => :author_id, :as => :taggable, :class_name => 'Tagging'
+  has_many :tags_using_author_id, :through => :taggings_using_author_id, :source => :tag
+
+  has_many :standard_categorizations, :class_name => 'Categorization', :foreign_key => :post_id
+  has_many :author_using_custom_pk,  :through => :standard_categorizations
+  has_many :authors_using_custom_pk, :through => :standard_categorizations
+  has_many :named_categories, :through => :standard_categorizations
+
+  has_many :readers
+  has_many :secure_readers
+  has_many :readers_with_person, -> { includes(:person) }, :class_name => "Reader"
+  has_many :people, :through => :readers
+  has_many :single_people, :through => :readers
+  has_many :people_with_callbacks, :source=>:person, :through => :readers,
+              :before_add    => lambda {|owner, reader| log(:added,   :before, reader.first_name) },
+              :after_add     => lambda {|owner, reader| log(:added,   :after,  reader.first_name) },
+              :before_remove => lambda {|owner, reader| log(:removed, :before, reader.first_name) },
+              :after_remove  => lambda {|owner, reader| log(:removed, :after,  reader.first_name) }
+  has_many :skimmers, -> { where :skimmer => true }, :class_name => 'Reader'
+  has_many :impatient_people, :through => :skimmers, :source => :person
+
+  has_many :lazy_readers
+  has_many :lazy_readers_skimmers_or_not, -> { where(skimmer: [ true, false ]) }, :class_name => 'LazyReader'
+
+  has_many :lazy_people, :through => :lazy_readers, :source => :person
+  has_many :lazy_readers_unscope_skimmers, -> { skimmers_or_not }, :class_name => 'LazyReader'
+  has_many :lazy_people_unscope_skimmers, :through => :lazy_readers_unscope_skimmers, :source => :person
+
+  def self.top(limit)
+    ranked_by_comments.limit_by(limit)
+  end
+
+  def self.written_by(author)
+    where(id: author.posts.pluck(:id))
+  end
+
+  def self.reset_log
+    @log = []
+  end
+
+  def self.log(message=nil, side=nil, new_record=nil)
+    return @log if message.nil?
+    @log << [message, side, new_record]
+  end
+end
+
+class SpecialPost < Post; end
+
+class StiPost < Post
+  self.abstract_class = true
+  has_one :special_comment, :class_name => "SpecialComment"
+end
+
+class SubStiPost < StiPost
+  self.table_name = Post.table_name
+end
+
+class FirstPost < ActiveRecord::Base
+  self.table_name = 'posts'
+  default_scope { where(:id => 1) }
+
+  has_many :comments, :foreign_key => :post_id
+  has_one  :comment,  :foreign_key => :post_id
+end
+
+class PostWithDefaultInclude < ActiveRecord::Base
+  self.table_name = 'posts'
+  default_scope { includes(:comments) }
+  has_many :comments, :foreign_key => :post_id
+end
+
+class PostWithSpecialCategorization < Post
+  has_many :categorizations, :foreign_key => :post_id
+  default_scope { where(:type => 'PostWithSpecialCategorization').joins(:categorizations).where(:categorizations => { :special => true }) }
+end
+
+class PostWithDefaultScope < ActiveRecord::Base
+  self.table_name = 'posts'
+  default_scope { order(:title) }
+end
+
+class SpecialPostWithDefaultScope < ActiveRecord::Base
+  self.table_name = 'posts'
+  default_scope { where(:id => [1, 5,6]) }
+end
+
+class PostThatLoadsCommentsInAnAfterSaveHook < ActiveRecord::Base
+  self.table_name = 'posts'
+  has_many :comments, class_name: "CommentThatAutomaticallyAltersPostBody", foreign_key: :post_id
+
+  after_save do |post|
+    post.comments.load
+  end
+end
diff --git a/activerecord/test/models/price_estimate.rb b/activerecord/test/models/price_estimate.rb
new file mode 100644
index 0000000000..d09e2a88a3
--- /dev/null
+++ b/activerecord/test/models/price_estimate.rb
@@ -0,0 +1,4 @@
+class PriceEstimate < ActiveRecord::Base
+  belongs_to :estimate_of, :polymorphic => true
+  belongs_to :thing, polymorphic: true
+end
diff --git a/activerecord/test/models/project.rb b/activerecord/test/models/project.rb
new file mode 100644
index 0000000000..7f42a4b1f8
--- /dev/null
+++ b/activerecord/test/models/project.rb
@@ -0,0 +1,29 @@
+class Project < ActiveRecord::Base
+  has_and_belongs_to_many :developers, -> { distinct.order 'developers.name desc, developers.id desc' }
+  has_and_belongs_to_many :readonly_developers, -> { readonly }, :class_name => "Developer"
+  has_and_belongs_to_many :non_unique_developers, -> { order 'developers.name desc, developers.id desc' }, :class_name => 'Developer'
+  has_and_belongs_to_many :limited_developers, -> { limit 1 }, :class_name => "Developer"
+  has_and_belongs_to_many :developers_named_david, -> { where("name = 'David'").distinct }, :class_name => "Developer"
+  has_and_belongs_to_many :developers_named_david_with_hash_conditions, -> { where(:name => 'David').distinct }, :class_name => "Developer"
+  has_and_belongs_to_many :salaried_developers, -> { where "salary > 0" }, :class_name => "Developer"
+  has_and_belongs_to_many :developers_with_callbacks, :class_name => "Developer", :before_add => Proc.new {|o, r| o.developers_log << "before_adding#{r.id || '<new>'}"},
+                            :after_add => Proc.new {|o, r| o.developers_log << "after_adding#{r.id || '<new>'}"},
+                            :before_remove => Proc.new {|o, r| o.developers_log << "before_removing#{r.id}"},
+                            :after_remove => Proc.new {|o, r| o.developers_log << "after_removing#{r.id}"}
+  has_and_belongs_to_many :well_payed_salary_groups, -> { group("developers.salary").having("SUM(salary) > 10000").select("SUM(salary) as salary") }, :class_name => "Developer"
+
+  attr_accessor :developers_log
+  after_initialize :set_developers_log
+
+  def set_developers_log
+    @developers_log = []
+  end
+
+  def self.all_as_method
+    all
+  end
+  scope :all_as_scope, -> { all }
+end
+
+class SpecialProject < Project
+end
diff --git a/activerecord/test/models/publisher.rb b/activerecord/test/models/publisher.rb
new file mode 100644
index 0000000000..0d4a7f9235
--- /dev/null
+++ b/activerecord/test/models/publisher.rb
@@ -0,0 +1,2 @@
+module Publisher
+end
diff --git a/activerecord/test/models/publisher/article.rb b/activerecord/test/models/publisher/article.rb
new file mode 100644
index 0000000000..d73a8eb936
--- /dev/null
+++ b/activerecord/test/models/publisher/article.rb
@@ -0,0 +1,4 @@
+class Publisher::Article < ActiveRecord::Base
+  has_and_belongs_to_many :magazines
+  has_and_belongs_to_many :tags
+end
diff --git a/activerecord/test/models/publisher/magazine.rb b/activerecord/test/models/publisher/magazine.rb
new file mode 100644
index 0000000000..82e1a14008
--- /dev/null
+++ b/activerecord/test/models/publisher/magazine.rb
@@ -0,0 +1,3 @@
+class Publisher::Magazine < ActiveRecord::Base
+  has_and_belongs_to_many :articles
+end
diff --git a/activerecord/test/models/randomly_named_c1.rb b/activerecord/test/models/randomly_named_c1.rb
new file mode 100644
index 0000000000..18a86c4989
--- /dev/null
+++ b/activerecord/test/models/randomly_named_c1.rb
@@ -0,0 +1,3 @@
+class ClassNameThatDoesNotFollowCONVENTIONS < ActiveRecord::Base

+  self.table_name = :randomly_named_table

+end

diff --git a/activerecord/test/models/rating.rb b/activerecord/test/models/rating.rb
new file mode 100644
index 0000000000..25a52c4ad7
--- /dev/null
+++ b/activerecord/test/models/rating.rb
@@ -0,0 +1,4 @@
+class Rating < ActiveRecord::Base
+  belongs_to :comment
+  has_many :taggings, :as => :taggable
+end
diff --git a/activerecord/test/models/reader.rb b/activerecord/test/models/reader.rb
new file mode 100644
index 0000000000..91afc1898c
--- /dev/null
+++ b/activerecord/test/models/reader.rb
@@ -0,0 +1,23 @@
+class Reader < ActiveRecord::Base
+  belongs_to :post
+  belongs_to :person, :inverse_of => :readers
+  belongs_to :single_person, :class_name => 'Person', :foreign_key => :person_id, :inverse_of => :reader
+  belongs_to :first_post, -> { where(id: [2, 3]) }
+end
+
+class SecureReader < ActiveRecord::Base
+  self.table_name = "readers"
+
+  belongs_to :secure_post, :class_name => "Post", :foreign_key => "post_id"
+  belongs_to :secure_person, :inverse_of => :secure_readers, :class_name => "Person", :foreign_key => "person_id"
+end
+
+class LazyReader < ActiveRecord::Base
+  self.table_name = "readers"
+  default_scope -> { where(skimmer: true) }
+
+  scope :skimmers_or_not, -> { unscope(:where => :skimmer) }
+
+  belongs_to :post
+  belongs_to :person
+end
diff --git a/activerecord/test/models/record.rb b/activerecord/test/models/record.rb
new file mode 100644
index 0000000000..f77ac9fc03
--- /dev/null
+++ b/activerecord/test/models/record.rb
@@ -0,0 +1,2 @@
+class Record < ActiveRecord::Base
+end
diff --git a/activerecord/test/models/reference.rb b/activerecord/test/models/reference.rb
new file mode 100644
index 0000000000..c2f9068f57
--- /dev/null
+++ b/activerecord/test/models/reference.rb
@@ -0,0 +1,22 @@
+class Reference < ActiveRecord::Base
+  belongs_to :person
+  belongs_to :job
+
+  has_many :agents_posts_authors, :through => :person
+
+  class << self; attr_accessor :make_comments; end
+  self.make_comments = false
+
+  before_destroy :make_comments
+
+  def make_comments
+    if self.class.make_comments
+      person.update comments: "Reference destroyed"
+    end
+  end
+end
+
+class BadReference < ActiveRecord::Base
+  self.table_name = 'references'
+  default_scope { where(:favourite => false) }
+end
diff --git a/activerecord/test/models/reply.rb b/activerecord/test/models/reply.rb
new file mode 100644
index 0000000000..3e82e55d89
--- /dev/null
+++ b/activerecord/test/models/reply.rb
@@ -0,0 +1,61 @@
+require 'models/topic'
+
+class Reply < Topic
+  belongs_to :topic, :foreign_key => "parent_id", :counter_cache => true
+  belongs_to :topic_with_primary_key, :class_name => "Topic", :primary_key => "title", :foreign_key => "parent_title", :counter_cache => "replies_count"
+  has_many :replies, :class_name => "SillyReply", :dependent => :destroy, :foreign_key => "parent_id"
+end
+
+class UniqueReply < Reply
+  belongs_to :topic, :foreign_key => 'parent_id', :counter_cache => true
+  validates_uniqueness_of :content, :scope => 'parent_id'
+end
+
+class SillyUniqueReply < UniqueReply
+end
+
+class WrongReply < Reply
+  validate :errors_on_empty_content
+  validate :title_is_wrong_create, :on => :create
+
+  validate :check_empty_title
+  validate :check_content_mismatch, :on => :create
+  validate :check_wrong_update, :on => :update
+  validate :check_author_name_is_secret, :on => :special_case
+
+  def check_empty_title
+    errors[:title] << "Empty" unless attribute_present?("title")
+  end
+
+  def errors_on_empty_content
+    errors[:content] << "Empty" unless attribute_present?("content")
+  end
+
+  def check_content_mismatch
+    if attribute_present?("title") && attribute_present?("content") && content == "Mismatch"
+      errors[:title] << "is Content Mismatch"
+    end
+  end
+
+  def title_is_wrong_create
+    errors[:title] << "is Wrong Create" if attribute_present?("title") && title == "Wrong Create"
+  end
+
+  def check_wrong_update
+    errors[:title] << "is Wrong Update" if attribute_present?("title") && title == "Wrong Update"
+  end
+
+  def check_author_name_is_secret
+    errors[:author_name] << "Invalid" unless author_name == "secret"
+  end
+end
+
+class SillyReply < Reply
+  belongs_to :reply, :foreign_key => "parent_id", :counter_cache => :replies_count
+end
+
+module Web
+  class Reply < Web::Topic
+    belongs_to :topic, :foreign_key => "parent_id", :counter_cache => true, :class_name => 'Web::Topic'
+  end
+end
diff --git a/activerecord/test/models/ship.rb b/activerecord/test/models/ship.rb
new file mode 100644
index 0000000000..77a4728d0b
--- /dev/null
+++ b/activerecord/test/models/ship.rb
@@ -0,0 +1,25 @@
+class Ship < ActiveRecord::Base
+  self.record_timestamps = false
+
+  belongs_to :pirate
+  belongs_to :update_only_pirate, :class_name => 'Pirate'
+  has_many :parts, :class_name => 'ShipPart'
+
+  accepts_nested_attributes_for :parts, :allow_destroy => true
+  accepts_nested_attributes_for :pirate, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? }
+  accepts_nested_attributes_for :update_only_pirate, :update_only => true
+
+  validates_presence_of :name
+
+  attr_accessor :cancel_save_from_callback
+  before_save :cancel_save_callback_method, :if => :cancel_save_from_callback
+  def cancel_save_callback_method
+    false
+  end
+end
+
+class FamousShip < ActiveRecord::Base
+  self.table_name = 'ships'
+  belongs_to :famous_pirate
+  validates_presence_of :name, on: :conference
+end
diff --git a/activerecord/test/models/ship_part.rb b/activerecord/test/models/ship_part.rb
new file mode 100644
index 0000000000..b6a8a506b4
--- /dev/null
+++ b/activerecord/test/models/ship_part.rb
@@ -0,0 +1,7 @@
+class ShipPart < ActiveRecord::Base
+  belongs_to :ship
+  has_many :trinkets, :class_name => "Treasure", :as => :looter
+  accepts_nested_attributes_for :trinkets, :allow_destroy => true
+
+  validates_presence_of :name
+end
\ No newline at end of file
diff --git a/activerecord/test/models/shop.rb b/activerecord/test/models/shop.rb
new file mode 100644
index 0000000000..607a0a5b41
--- /dev/null
+++ b/activerecord/test/models/shop.rb
@@ -0,0 +1,17 @@
+module Shop
+  class Collection < ActiveRecord::Base
+    has_many :products, :dependent => :nullify
+  end
+
+  class Product < ActiveRecord::Base
+    has_many :variants, :dependent => :delete_all
+    belongs_to :type
+
+    class Type < ActiveRecord::Base
+      has_many :products
+    end
+  end
+
+  class Variant < ActiveRecord::Base
+  end
+end
diff --git a/activerecord/test/models/speedometer.rb b/activerecord/test/models/speedometer.rb
new file mode 100644
index 0000000000..497c3aba9a
--- /dev/null
+++ b/activerecord/test/models/speedometer.rb
@@ -0,0 +1,6 @@
+class Speedometer < ActiveRecord::Base
+  self.primary_key = :speedometer_id
+  belongs_to :dashboard
+
+  has_many :minivans
+end
diff --git a/activerecord/test/models/sponsor.rb b/activerecord/test/models/sponsor.rb
new file mode 100644
index 0000000000..ec3dcf8a97
--- /dev/null
+++ b/activerecord/test/models/sponsor.rb
@@ -0,0 +1,7 @@
+class Sponsor < ActiveRecord::Base
+  belongs_to :sponsor_club, :class_name => "Club", :foreign_key => "club_id"
+  belongs_to :sponsorable, :polymorphic => true
+  belongs_to :thing, :polymorphic => true, :foreign_type => :sponsorable_type, :foreign_key => :sponsorable_id
+  belongs_to :sponsorable_with_conditions, -> { where :name => 'Ernie'}, :polymorphic => true,
+             :foreign_type => 'sponsorable_type', :foreign_key => 'sponsorable_id'
+end
diff --git a/activerecord/test/models/string_key_object.rb b/activerecord/test/models/string_key_object.rb
new file mode 100644
index 0000000000..f084ec1bdc
--- /dev/null
+++ b/activerecord/test/models/string_key_object.rb
@@ -0,0 +1,3 @@
+class StringKeyObject < ActiveRecord::Base
+  self.primary_key = :id
+end
diff --git a/activerecord/test/models/student.rb b/activerecord/test/models/student.rb
new file mode 100644
index 0000000000..28a0b6c99b
--- /dev/null
+++ b/activerecord/test/models/student.rb
@@ -0,0 +1,4 @@
+class Student < ActiveRecord::Base
+  has_and_belongs_to_many :lessons
+  belongs_to :college
+end
diff --git a/activerecord/test/models/subject.rb b/activerecord/test/models/subject.rb
new file mode 100644
index 0000000000..8e28f8b86b
--- /dev/null
+++ b/activerecord/test/models/subject.rb
@@ -0,0 +1,16 @@
+# used for OracleSynonymTest, see test/synonym_test_oracle.rb
+#
+class Subject < ActiveRecord::Base
+
+  # added initialization of author_email_address in the same way as in Topic class
+  # as otherwise synonym test was failing
+  after_initialize :set_email_address
+
+  protected
+    def set_email_address
+      unless self.persisted?
+        self.author_email_address = 'test@test.com'
+      end
+    end
+
+end
diff --git a/activerecord/test/models/subscriber.rb b/activerecord/test/models/subscriber.rb
new file mode 100644
index 0000000000..76e85a0cd3
--- /dev/null
+++ b/activerecord/test/models/subscriber.rb
@@ -0,0 +1,8 @@
+class Subscriber < ActiveRecord::Base
+  self.primary_key = 'nick'
+  has_many :subscriptions
+  has_many :books, :through => :subscriptions
+end
+
+class SpecialSubscriber < Subscriber
+end
diff --git a/activerecord/test/models/subscription.rb b/activerecord/test/models/subscription.rb
new file mode 100644
index 0000000000..bcac4738a3
--- /dev/null
+++ b/activerecord/test/models/subscription.rb
@@ -0,0 +1,4 @@
+class Subscription < ActiveRecord::Base
+  belongs_to :subscriber, :counter_cache => :books_count
+  belongs_to :book
+end
diff --git a/activerecord/test/models/tag.rb b/activerecord/test/models/tag.rb
new file mode 100644
index 0000000000..80d4725f7e
--- /dev/null
+++ b/activerecord/test/models/tag.rb
@@ -0,0 +1,7 @@
+class Tag < ActiveRecord::Base
+  has_many :taggings
+  has_many :taggables, :through => :taggings
+  has_one  :tagging
+
+  has_many :tagged_posts, :through => :taggings, :source => 'taggable', :source_type => 'Post'
+end
diff --git a/activerecord/test/models/tagging.rb b/activerecord/test/models/tagging.rb
new file mode 100644
index 0000000000..a6c05da26a
--- /dev/null
+++ b/activerecord/test/models/tagging.rb
@@ -0,0 +1,13 @@
+# test that attr_readonly isn't called on the :taggable polymorphic association
+module Taggable
+end
+
+class Tagging < ActiveRecord::Base
+  belongs_to :tag, -> { includes(:tagging) }
+  belongs_to :super_tag,   :class_name => 'Tag', :foreign_key => 'super_tag_id'
+  belongs_to :invalid_tag, :class_name => 'Tag', :foreign_key => 'tag_id'
+  belongs_to :blue_tag, -> { where :tags => { :name => 'Blue' } }, :class_name => 'Tag', :foreign_key => :tag_id
+  belongs_to :tag_with_primary_key, :class_name => 'Tag', :foreign_key => :tag_id, :primary_key => :custom_primary_key
+  belongs_to :taggable, :polymorphic => true, :counter_cache => :tags_count
+  has_many :things, :through => :taggable
+end
diff --git a/activerecord/test/models/task.rb b/activerecord/test/models/task.rb
new file mode 100644
index 0000000000..e36989dd56
--- /dev/null
+++ b/activerecord/test/models/task.rb
@@ -0,0 +1,5 @@
+class Task < ActiveRecord::Base
+  def updated_at
+    ending
+  end
+end
diff --git a/activerecord/test/models/topic.rb b/activerecord/test/models/topic.rb
new file mode 100644
index 0000000000..f81ffe1d90
--- /dev/null
+++ b/activerecord/test/models/topic.rb
@@ -0,0 +1,124 @@
+class Topic < ActiveRecord::Base
+  scope :base, -> { all }
+  scope :written_before, lambda { |time|
+    if time
+      where 'written_on < ?', time
+    end
+  }
+  scope :approved, -> { where(:approved => true) }
+  scope :rejected, -> { where(:approved => false) }
+
+  scope :scope_with_lambda, lambda { all }
+
+  scope :by_lifo, -> { where(:author_name => 'lifo') }
+  scope :replied, -> { where 'replies_count > 0' }
+
+  scope 'approved_as_string', -> { where(:approved => true) }
+  scope :anonymous_extension, -> { all } do
+    def one
+      1
+    end
+  end
+
+  scope :with_object, Class.new(Struct.new(:klass)) {
+    def call
+      klass.where(:approved => true)
+    end
+  }.new(self)
+
+  module NamedExtension
+    def two
+      2
+    end
+  end
+
+  has_many :replies, :dependent => :destroy, :foreign_key => "parent_id"
+  has_many :approved_replies, -> { approved }, class_name: 'Reply', foreign_key: "parent_id", counter_cache: 'replies_count'
+
+  has_many :unique_replies, :dependent => :destroy, :foreign_key => "parent_id"
+  has_many :silly_unique_replies, :dependent => :destroy, :foreign_key => "parent_id"
+
+  serialize :content
+
+  before_create  :default_written_on
+  before_destroy :destroy_children
+
+  # Explicitly define as :date column so that returned Oracle DATE values would be typecasted to Date and not Time.
+  # Some tests depend on assumption that this attribute will have Date values.
+  if current_adapter?(:OracleEnhancedAdapter)
+    set_date_columns :last_read
+  end
+
+  def parent
+    Topic.find(parent_id)
+  end
+
+  # trivial method for testing Array#to_xml with :methods
+  def topic_id
+    id
+  end
+
+  alias_attribute :heading, :title
+
+  before_validation :before_validation_for_transaction
+  before_save :before_save_for_transaction
+  before_destroy :before_destroy_for_transaction
+
+  after_save :after_save_for_transaction
+  after_create :after_create_for_transaction
+
+  after_initialize :set_email_address
+
+  class_attribute :after_initialize_called
+  after_initialize do
+    self.class.after_initialize_called = true
+  end
+
+  def approved=(val)
+    @custom_approved = val
+    write_attribute(:approved, val)
+  end
+
+  protected
+
+    def default_written_on
+      self.written_on = Time.now unless attribute_present?("written_on")
+    end
+
+    def destroy_children
+      self.class.delete_all "parent_id = #{id}"
+    end
+
+    def set_email_address
+      unless self.persisted?
+        self.author_email_address = 'test@test.com'
+      end
+    end
+
+    def before_validation_for_transaction; end
+    def before_save_for_transaction; end
+    def before_destroy_for_transaction; end
+    def after_save_for_transaction; end
+    def after_create_for_transaction; end
+end
+
+class ImportantTopic < Topic
+  serialize :important, Hash
+end
+
+class DefaultRejectedTopic < Topic
+  default_scope -> { where(approved: false) }
+end
+
+class BlankTopic < Topic
+  # declared here to make sure that dynamic finder with a bang can find a model that responds to `blank?`
+  def blank?
+    true
+  end
+end
+
+module Web
+  class Topic < ActiveRecord::Base
+    has_many :replies, :dependent => :destroy, :foreign_key => "parent_id", :class_name => 'Web::Reply'
+  end
+end
diff --git a/activerecord/test/models/toy.rb b/activerecord/test/models/toy.rb
new file mode 100644
index 0000000000..ddc7048a56
--- /dev/null
+++ b/activerecord/test/models/toy.rb
@@ -0,0 +1,6 @@
+class Toy < ActiveRecord::Base
+  self.primary_key = :toy_id
+  belongs_to :pet
+
+  scope :with_pet, -> { joins(:pet) }
+end
diff --git a/activerecord/test/models/traffic_light.rb b/activerecord/test/models/traffic_light.rb
new file mode 100644
index 0000000000..a6b7edb882
--- /dev/null
+++ b/activerecord/test/models/traffic_light.rb
@@ -0,0 +1,4 @@
+class TrafficLight < ActiveRecord::Base
+  serialize :state, Array
+  serialize :long_state, Array
+end
diff --git a/activerecord/test/models/treasure.rb b/activerecord/test/models/treasure.rb
new file mode 100644
index 0000000000..a69d3fd3df
--- /dev/null
+++ b/activerecord/test/models/treasure.rb
@@ -0,0 +1,12 @@
+class Treasure < ActiveRecord::Base
+  has_and_belongs_to_many :parrots
+  belongs_to :looter, :polymorphic => true
+
+  has_many :price_estimates, :as => :estimate_of
+  has_and_belongs_to_many :rich_people, join_table: 'peoples_treasures', validate: false
+
+  accepts_nested_attributes_for :looter
+end
+
+class HiddenTreasure < Treasure
+end
diff --git a/activerecord/test/models/treaty.rb b/activerecord/test/models/treaty.rb
new file mode 100644
index 0000000000..41fd1350f3
--- /dev/null
+++ b/activerecord/test/models/treaty.rb
@@ -0,0 +1,7 @@
+class Treaty < ActiveRecord::Base
+
+  self.primary_key = :treaty_id
+
+  has_and_belongs_to_many :countries
+
+end
diff --git a/activerecord/test/models/tyre.rb b/activerecord/test/models/tyre.rb
new file mode 100644
index 0000000000..bc3444aa7d
--- /dev/null
+++ b/activerecord/test/models/tyre.rb
@@ -0,0 +1,3 @@
+class Tyre < ActiveRecord::Base
+  belongs_to :car
+end
diff --git a/activerecord/test/models/uuid_child.rb b/activerecord/test/models/uuid_child.rb
new file mode 100644
index 0000000000..a3d0962ad6
--- /dev/null
+++ b/activerecord/test/models/uuid_child.rb
@@ -0,0 +1,3 @@
+class UuidChild < ActiveRecord::Base
+  belongs_to :uuid_parent
+end
diff --git a/activerecord/test/models/uuid_parent.rb b/activerecord/test/models/uuid_parent.rb
new file mode 100644
index 0000000000..5634f22d0c
--- /dev/null
+++ b/activerecord/test/models/uuid_parent.rb
@@ -0,0 +1,3 @@
+class UuidParent < ActiveRecord::Base
+  has_many :uuid_children
+end
diff --git a/activerecord/test/models/vegetables.rb b/activerecord/test/models/vegetables.rb
new file mode 100644
index 0000000000..1f41cde3a5
--- /dev/null
+++ b/activerecord/test/models/vegetables.rb
@@ -0,0 +1,24 @@
+class Vegetable < ActiveRecord::Base
+
+  validates_presence_of :name
+
+  def self.inheritance_column
+    'custom_type'
+  end
+end
+
+class Cucumber < Vegetable
+end
+
+class Cabbage < Vegetable
+end
+
+class GreenCabbage < Cabbage
+end
+
+class KingCole < GreenCabbage
+end
+
+class RedCabbage < Cabbage
+  belongs_to :seller, :class_name => 'Company'
+end
diff --git a/activerecord/test/models/vertex.rb b/activerecord/test/models/vertex.rb
new file mode 100644
index 0000000000..48bb851e62
--- /dev/null
+++ b/activerecord/test/models/vertex.rb
@@ -0,0 +1,9 @@
+# This class models a vertex in a directed graph.
+class Vertex < ActiveRecord::Base
+  has_many :sink_edges, :class_name => 'Edge', :foreign_key => 'source_id'
+  has_many :sinks, :through => :sink_edges
+
+  has_and_belongs_to_many :sources,
+    :class_name => 'Vertex', :join_table => 'edges',
+    :foreign_key => 'sink_id', :association_foreign_key => 'source_id'
+end
diff --git a/activerecord/test/models/warehouse_thing.rb b/activerecord/test/models/warehouse_thing.rb
new file mode 100644
index 0000000000..f20bd1a245
--- /dev/null
+++ b/activerecord/test/models/warehouse_thing.rb
@@ -0,0 +1,5 @@
+class WarehouseThing < ActiveRecord::Base
+  self.table_name = "warehouse-things"
+
+  validates_uniqueness_of :value
+end
diff --git a/activerecord/test/models/wheel.rb b/activerecord/test/models/wheel.rb
new file mode 100644
index 0000000000..26868bce5e
--- /dev/null
+++ b/activerecord/test/models/wheel.rb
@@ -0,0 +1,3 @@
+class Wheel < ActiveRecord::Base
+  belongs_to :wheelable, :polymorphic => true, :counter_cache => true
+end
diff --git a/activerecord/test/models/without_table.rb b/activerecord/test/models/without_table.rb
new file mode 100644
index 0000000000..50c824e4ac
--- /dev/null
+++ b/activerecord/test/models/without_table.rb
@@ -0,0 +1,3 @@
+class WithoutTable < ActiveRecord::Base
+  default_scope -> { where(:published => true) }
+end
diff --git a/activerecord/test/models/zine.rb b/activerecord/test/models/zine.rb
new file mode 100644
index 0000000000..c2d0fdaf25
--- /dev/null
+++ b/activerecord/test/models/zine.rb
@@ -0,0 +1,3 @@
+class Zine < ActiveRecord::Base
+  has_many :interests, :inverse_of => :zine
+end
diff --git a/activerecord/test/schema/mysql2_specific_schema.rb b/activerecord/test/schema/mysql2_specific_schema.rb
new file mode 100644
index 0000000000..a9a6514c9d
--- /dev/null
+++ b/activerecord/test/schema/mysql2_specific_schema.rb
@@ -0,0 +1,58 @@
+ActiveRecord::Schema.define do
+  create_table :binary_fields, force: true do |t|
+    t.binary :var_binary, limit: 255
+    t.binary :var_binary_large, limit: 4095
+    t.column :tiny_blob, 'tinyblob', limit: 255
+    t.binary :normal_blob, limit: 65535
+    t.binary :medium_blob, limit: 16777215
+    t.binary :long_blob, limit: 2147483647
+    t.text   :tiny_text, limit: 255
+    t.text   :normal_text, limit: 65535
+    t.text   :medium_text, limit: 16777215
+    t.text   :long_text, limit: 2147483647
+  end
+
+  add_index :binary_fields, :var_binary
+
+  create_table :key_tests, force: true, :options => 'ENGINE=MyISAM' do |t|
+    t.string :awesome
+    t.string :pizza
+    t.string :snacks
+  end
+
+  add_index :key_tests, :awesome, :type => :fulltext, :name => 'index_key_tests_on_awesome'
+  add_index :key_tests, :pizza, :using => :btree, :name => 'index_key_tests_on_pizza'
+  add_index :key_tests, :snacks, :name => 'index_key_tests_on_snack'
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP PROCEDURE IF EXISTS ten;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE PROCEDURE ten() SQL SECURITY INVOKER
+BEGIN
+	select 10;
+END
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP TABLE IF EXISTS collation_tests;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE TABLE collation_tests (
+  string_cs_column VARCHAR(1) COLLATE utf8_bin,
+  string_ci_column VARCHAR(1) COLLATE utf8_general_ci
+) CHARACTER SET utf8 COLLATE utf8_general_ci
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP TABLE IF EXISTS enum_tests;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE TABLE enum_tests (
+  enum_column ENUM('text','blob','tiny','medium','long')
+)
+SQL
+end
diff --git a/activerecord/test/schema/mysql_specific_schema.rb b/activerecord/test/schema/mysql_specific_schema.rb
new file mode 100644
index 0000000000..f2cffca52c
--- /dev/null
+++ b/activerecord/test/schema/mysql_specific_schema.rb
@@ -0,0 +1,70 @@
+ActiveRecord::Schema.define do
+  create_table :binary_fields, force: true do |t|
+    t.binary :var_binary, limit: 255
+    t.binary :var_binary_large, limit: 4095
+    t.column :tiny_blob, 'tinyblob', limit: 255
+    t.binary :normal_blob, limit: 65535
+    t.binary :medium_blob, limit: 16777215
+    t.binary :long_blob, limit: 2147483647
+    t.text   :tiny_text, limit: 255
+    t.text   :normal_text, limit: 65535
+    t.text   :medium_text, limit: 16777215
+    t.text   :long_text, limit: 2147483647
+  end
+
+  add_index :binary_fields, :var_binary
+
+  create_table :key_tests, force: true, :options => 'ENGINE=MyISAM' do |t|
+    t.string :awesome
+    t.string :pizza
+    t.string :snacks
+  end
+
+  add_index :key_tests, :awesome, :type => :fulltext, :name => 'index_key_tests_on_awesome'
+  add_index :key_tests, :pizza, :using => :btree, :name => 'index_key_tests_on_pizza'
+  add_index :key_tests, :snacks, :name => 'index_key_tests_on_snack'
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP PROCEDURE IF EXISTS ten;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE PROCEDURE ten() SQL SECURITY INVOKER
+BEGIN
+	select 10;
+END
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP PROCEDURE IF EXISTS topics;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE PROCEDURE topics() SQL SECURITY INVOKER
+BEGIN
+	select * from topics limit 1;
+END
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP TABLE IF EXISTS collation_tests;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE TABLE collation_tests (
+  string_cs_column VARCHAR(1) COLLATE utf8_bin,
+  string_ci_column VARCHAR(1) COLLATE utf8_general_ci
+) CHARACTER SET utf8 COLLATE utf8_general_ci
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+DROP TABLE IF EXISTS enum_tests;
+SQL
+
+  ActiveRecord::Base.connection.execute <<-SQL
+CREATE TABLE enum_tests (
+  enum_column ENUM('text','blob','tiny','medium','long')
+)
+SQL
+
+end
diff --git a/activerecord/test/schema/oracle_specific_schema.rb b/activerecord/test/schema/oracle_specific_schema.rb
new file mode 100644
index 0000000000..a7817772f4
--- /dev/null
+++ b/activerecord/test/schema/oracle_specific_schema.rb
@@ -0,0 +1,43 @@
+ActiveRecord::Schema.define do
+
+  execute "drop table test_oracle_defaults" rescue nil
+  execute "drop sequence test_oracle_defaults_seq" rescue nil
+  execute "drop sequence companies_nonstd_seq" rescue nil
+  execute "drop table defaults" rescue nil
+  execute "drop sequence defaults_seq" rescue nil
+
+  execute <<-SQL
+create table test_oracle_defaults (
+  id integer not null primary key,
+  test_char char(1) default 'X' not null,
+  test_string varchar2(20) default 'hello' not null,
+  test_int integer default 3 not null
+)
+  SQL
+
+  execute <<-SQL
+create sequence test_oracle_defaults_seq minvalue 10000
+  SQL
+
+  execute "create sequence companies_nonstd_seq minvalue 10000"
+
+  execute <<-SQL
+  CREATE TABLE defaults (
+      id integer not null,
+      modified_date date default sysdate,
+      modified_date_function date default sysdate,
+      fixed_date date default to_date('2004-01-01', 'YYYY-MM-DD'),
+      modified_time date default sysdate,
+      modified_time_function date default sysdate,
+      fixed_time date default TO_DATE('2004-01-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS'),
+      char1 varchar2(1) default 'Y',
+      char2 varchar2(50) default 'a varchar field',
+      char3 clob default 'a text field',
+      positive_integer integer default 1,
+      negative_integer integer default -1,
+      decimal_number number(3,2) default 2.78
+  )
+  SQL
+  execute "create sequence defaults_seq minvalue 10000"
+
+end
diff --git a/activerecord/test/schema/postgresql_specific_schema.rb b/activerecord/test/schema/postgresql_specific_schema.rb
new file mode 100644
index 0000000000..e9294a11b9
--- /dev/null
+++ b/activerecord/test/schema/postgresql_specific_schema.rb
@@ -0,0 +1,205 @@
+ActiveRecord::Schema.define do
+
+  %w(postgresql_tsvectors postgresql_hstores postgresql_arrays postgresql_moneys postgresql_numbers postgresql_times postgresql_network_addresses postgresql_uuids postgresql_ltrees
+      postgresql_oids postgresql_xml_data_type defaults geometrics postgresql_timestamp_with_zones postgresql_partitioned_table postgresql_partitioned_table_parent postgresql_json_data_type postgresql_citext).each do |table_name|
+    execute "DROP TABLE IF EXISTS #{quote_table_name table_name}"
+  end
+
+  execute 'DROP SEQUENCE IF EXISTS companies_nonstd_seq CASCADE'
+  execute 'CREATE SEQUENCE companies_nonstd_seq START 101 OWNED BY companies.id'
+  execute "ALTER TABLE companies ALTER COLUMN id SET DEFAULT nextval('companies_nonstd_seq')"
+  execute 'DROP SEQUENCE IF EXISTS companies_id_seq'
+
+  execute 'DROP FUNCTION IF EXISTS partitioned_insert_trigger()'
+
+  execute "DROP SCHEMA IF EXISTS schema_1 CASCADE"
+
+  %w(accounts_id_seq developers_id_seq projects_id_seq topics_id_seq customers_id_seq orders_id_seq).each do |seq_name|
+    execute "SELECT setval('#{seq_name}', 100)"
+  end
+
+  execute <<_SQL
+    CREATE TABLE defaults (
+    id serial primary key,
+    modified_date date default CURRENT_DATE,
+    modified_date_function date default now(),
+    fixed_date date default '2004-01-01',
+    modified_time timestamp default CURRENT_TIMESTAMP,
+    modified_time_function timestamp default now(),
+    fixed_time timestamp default '2004-01-01 00:00:00.000000-00',
+    char1 char(1) default 'Y',
+    char2 character varying(50) default 'a varchar field',
+    char3 text default 'a text field',
+    positive_integer integer default 1,
+    negative_integer integer default -1,
+    bigint_default bigint default 0::bigint,
+    decimal_number decimal(3,2) default 2.78,
+    multiline_default text DEFAULT '--- []
+
+'::text
+);
+_SQL
+
+  execute "CREATE SCHEMA schema_1"
+  execute "CREATE DOMAIN schema_1.text AS text"
+  execute "CREATE DOMAIN schema_1.varchar AS varchar"
+  execute "CREATE DOMAIN schema_1.bpchar AS bpchar"
+
+  execute <<_SQL
+  CREATE TABLE geometrics (
+    id serial primary key,
+    a_point point,
+    -- a_line line, (the line type is currently not implemented in postgresql)
+    a_line_segment lseg,
+    a_box box,
+    a_path path,
+    a_polygon polygon,
+    a_circle circle
+  );
+_SQL
+
+  execute <<_SQL
+  CREATE TABLE postgresql_arrays (
+    id SERIAL PRIMARY KEY,
+    commission_by_quarter INTEGER[],
+    nicknames TEXT[]
+  );
+_SQL
+
+  execute <<_SQL
+  CREATE TABLE postgresql_uuids (
+    id SERIAL PRIMARY KEY,
+    guid uuid,
+    compact_guid uuid
+  );
+_SQL
+
+  execute <<_SQL
+  CREATE TABLE postgresql_tsvectors (
+    id SERIAL PRIMARY KEY,
+    text_vector tsvector
+  );
+_SQL
+
+  if 't' == select_value("select 'hstore'=ANY(select typname from pg_type)")
+  execute <<_SQL
+  CREATE TABLE postgresql_hstores (
+    id SERIAL PRIMARY KEY,
+    hash_store hstore default ''::hstore
+  );
+_SQL
+  end
+
+  if 't' == select_value("select 'ltree'=ANY(select typname from pg_type)")
+  execute <<_SQL
+  CREATE TABLE postgresql_ltrees (
+    id SERIAL PRIMARY KEY,
+    path ltree
+  );
+_SQL
+  end
+
+  if 't' == select_value("select 'citext'=ANY(select typname from pg_type)")
+  execute <<_SQL
+  CREATE TABLE postgresql_citext (
+    id SERIAL PRIMARY KEY,
+    text_citext citext default ''::citext
+  );
+_SQL
+  end
+
+  if 't' == select_value("select 'json'=ANY(select typname from pg_type)")
+  execute <<_SQL
+  CREATE TABLE postgresql_json_data_type (
+    id SERIAL PRIMARY KEY,
+    json_data json default '{}'::json
+  );
+_SQL
+  end
+
+  execute <<_SQL
+  CREATE TABLE postgresql_numbers (
+    id SERIAL PRIMARY KEY,
+    single REAL,
+    double DOUBLE PRECISION
+  );
+_SQL
+
+  execute <<_SQL
+  CREATE TABLE postgresql_times (
+    id SERIAL PRIMARY KEY,
+    time_interval INTERVAL,
+    scaled_time_interval INTERVAL(6)
+  );
+_SQL
+
+  execute <<_SQL
+  CREATE TABLE postgresql_network_addresses (
+    id SERIAL PRIMARY KEY,
+    cidr_address CIDR default '192.168.1.0/24',
+    inet_address INET default '192.168.1.1',
+    mac_address MACADDR default 'ff:ff:ff:ff:ff:ff'
+  );
+_SQL
+
+  execute <<_SQL
+  CREATE TABLE postgresql_oids (
+    id SERIAL PRIMARY KEY,
+    obj_id OID
+  );
+_SQL
+
+  execute <<_SQL
+  CREATE TABLE postgresql_timestamp_with_zones (
+    id SERIAL PRIMARY KEY,
+    time TIMESTAMP WITH TIME ZONE
+  );
+_SQL
+
+  begin
+    execute <<_SQL
+    CREATE TABLE postgresql_partitioned_table_parent (
+      id SERIAL PRIMARY KEY,
+      number integer
+    );
+    CREATE TABLE postgresql_partitioned_table ( )
+      INHERITS (postgresql_partitioned_table_parent);
+
+    CREATE OR REPLACE FUNCTION partitioned_insert_trigger()
+    RETURNS TRIGGER AS $$
+    BEGIN
+      INSERT INTO postgresql_partitioned_table VALUES (NEW.*);
+      RETURN NULL;
+    END;
+    $$
+    LANGUAGE plpgsql;
+
+    CREATE TRIGGER insert_partitioning_trigger
+      BEFORE INSERT ON postgresql_partitioned_table_parent
+      FOR EACH ROW EXECUTE PROCEDURE partitioned_insert_trigger();
+_SQL
+  rescue ActiveRecord::StatementInvalid => e
+    if e.message =~ /language "plpgsql" does not exist/
+      execute "CREATE LANGUAGE 'plpgsql';"
+      retry
+    else
+      raise e
+    end
+  end
+
+  begin
+    execute <<_SQL
+    CREATE TABLE postgresql_xml_data_type (
+    id SERIAL PRIMARY KEY,
+    data xml
+    );
+_SQL
+  rescue #This version of PostgreSQL either has no XML support or is was not compiled with XML support: skipping table
+  end
+
+  # This table is to verify if the :limit option is being ignored for text and binary columns
+  create_table :limitless_fields, force: true do |t|
+    t.binary :binary, limit: 100_000
+    t.text :text, limit: 100_000
+  end
+end
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
new file mode 100644
index 0000000000..a8b21904ac
--- /dev/null
+++ b/activerecord/test/schema/schema.rb
@@ -0,0 +1,882 @@
+# encoding: utf-8
+
+ActiveRecord::Schema.define do
+  def except(adapter_names_to_exclude)
+    unless [adapter_names_to_exclude].flatten.include?(adapter_name)
+      yield
+    end
+  end
+
+  #put adapter specific setup here
+  case adapter_name
+  when "PostgreSQL"
+    enable_uuid_ossp!(ActiveRecord::Base.connection)
+    create_table :uuid_parents, id: :uuid, force: true do |t|
+      t.string :name
+    end
+    create_table :uuid_children, id: :uuid, force: true do |t|
+      t.string :name
+      t.uuid :uuid_parent_id
+    end
+  end
+
+
+  # ------------------------------------------------------------------- #
+  #                                                                     #
+  #   Please keep these create table statements in alphabetical order   #
+  #   unless the ordering matters.  In which case, define them below.   #
+  #                                                                     #
+  # ------------------------------------------------------------------- #
+
+  create_table :accounts, force: true do |t|
+    t.integer :firm_id
+    t.string  :firm_name
+    t.integer :credit_limit
+  end
+
+  create_table :admin_accounts, force: true do |t|
+    t.string :name
+  end
+
+  create_table :admin_users, force: true do |t|
+    t.string :name
+    t.string :settings, null: true, limit: 1024
+    # MySQL does not allow default values for blobs. Fake it out with a
+    # big varchar below.
+    t.string :preferences, null: true, default: '', limit: 1024
+    t.string :json_data, null: true, limit: 1024
+    t.string :json_data_empty, null: true, default: "", limit: 1024
+    t.text :params
+    t.references :account
+  end
+
+  create_table :aircraft, force: true do |t|
+    t.string :name
+  end
+
+  create_table :articles, force: true do |t|
+  end
+
+  create_table :articles_magazines, force: true do |t|
+    t.references :article
+    t.references :magazine
+  end
+
+  create_table :articles_tags, force: true do |t|
+    t.references :article
+    t.references :tag
+  end
+
+  create_table :audit_logs, force: true do |t|
+    t.column :message, :string, null: false
+    t.column :developer_id, :integer, null: false
+    t.integer :unvalidated_developer_id
+  end
+
+  create_table :authors, force: true do |t|
+    t.string :name, null: false
+    t.integer :author_address_id
+    t.integer :author_address_extra_id
+    t.string :organization_id
+    t.string :owned_essay_id
+  end
+
+  create_table :author_addresses, force: true do |t|
+  end
+
+  add_foreign_key :authors, :author_addresses
+
+  create_table :author_favorites, force: true do |t|
+    t.column :author_id, :integer
+    t.column :favorite_author_id, :integer
+  end
+
+  create_table :auto_id_tests, force: true, id: false do |t|
+    t.primary_key :auto_id
+    t.integer     :value
+  end
+
+  create_table :binaries, force: true do |t|
+    t.string :name
+    t.binary :data
+    t.binary :short_data, limit: 2048
+  end
+
+  create_table :birds, force: true do |t|
+    t.string :name
+    t.string :color
+    t.integer :pirate_id
+  end
+
+  create_table :books, force: true do |t|
+    t.integer :author_id
+    t.string :format
+    t.column :name, :string
+    t.column :status, :integer, default: 0
+    t.column :read_status, :integer, default: 0
+    t.column :nullable_status, :integer
+  end
+
+  create_table :booleans, force: true do |t|
+    t.boolean :value
+    t.boolean :has_fun, null: false, default: false
+  end
+
+  create_table :bulbs, force: true do |t|
+    t.integer :car_id
+    t.string  :name
+    t.boolean :frickinawesome
+    t.string :color
+  end
+
+  create_table "CamelCase", force: true do |t|
+    t.string :name
+  end
+
+  create_table :cars, force: true do |t|
+    t.string  :name
+    t.integer :engines_count
+    t.integer :wheels_count
+    t.column :lock_version, :integer, null: false, default: 0
+    t.timestamps
+  end
+
+  create_table :categories, force: true do |t|
+    t.string :name, null: false
+    t.string :type
+    t.integer :categorizations_count
+  end
+
+  create_table :categories_posts, force: true, id: false do |t|
+    t.integer :category_id, null: false
+    t.integer :post_id, null: false
+  end
+
+  create_table :categorizations, force: true do |t|
+    t.column :category_id, :integer
+    t.string :named_category_name
+    t.column :post_id, :integer
+    t.column :author_id, :integer
+    t.column :special, :boolean
+  end
+
+  create_table :citations, force: true do |t|
+    t.column :book1_id, :integer
+    t.column :book2_id, :integer
+  end
+
+  create_table :clubs, force: true do |t|
+    t.string :name
+    t.integer :category_id
+  end
+
+  create_table :collections, force: true do |t|
+    t.string :name
+  end
+
+  create_table :colnametests, force: true do |t|
+    t.integer :references, null: false
+  end
+
+  create_table :columns, force: true do |t|
+    t.references :record
+  end
+
+  create_table :comments, force: true do |t|
+    t.integer :post_id, null: false
+    # use VARCHAR2(4000) instead of CLOB datatype as CLOB data type has many limitations in
+    # Oracle SELECT WHERE clause which causes many unit test failures
+    if current_adapter?(:OracleAdapter)
+      t.string  :body, null: false, limit: 4000
+    else
+      t.text    :body, null: false
+    end
+    t.string  :type
+    t.integer :tags_count, default: 0
+    t.integer :children_count, default: 0
+    t.integer :parent_id
+    t.references :author, polymorphic: true
+    t.string :resource_id
+    t.string :resource_type
+  end
+
+  create_table :companies, force: true do |t|
+    t.string  :type
+    t.integer :firm_id
+    t.string  :firm_name
+    t.string  :name
+    t.integer :client_of
+    t.integer :rating, default: 1
+    t.integer :account_id
+    t.string :description, default: ""
+  end
+
+  add_index :companies, [:firm_id, :type, :rating], name: "company_index"
+  add_index :companies, [:firm_id, :type], name: "company_partial_index", where: "rating > 10"
+  add_index :companies, :name, name: 'company_name_index', using: :btree
+
+  create_table :vegetables, force: true do |t|
+    t.string :name
+    t.integer :seller_id
+    t.string :custom_type
+  end
+
+  create_table :computers, force: true do |t|
+    t.string :system
+    t.integer :developer, null: false
+    t.integer :extendedWarranty, null: false
+  end
+
+  create_table :contracts, force: true do |t|
+    t.integer :developer_id
+    t.integer :company_id
+  end
+
+  create_table :customers, force: true do |t|
+    t.string  :name
+    t.integer :balance, default: 0
+    t.string  :address_street
+    t.string  :address_city
+    t.string  :address_country
+    t.string  :gps_location
+  end
+
+  create_table :dashboards, force: true, id: false do |t|
+    t.string :dashboard_id
+    t.string :name
+  end
+
+  create_table :developers, force: true do |t|
+    t.string   :name
+    t.integer  :salary, default: 70000
+    t.datetime :created_at
+    t.datetime :updated_at
+    t.datetime :created_on
+    t.datetime :updated_on
+  end
+
+  create_table :developers_projects, force: true, id: false do |t|
+    t.integer :developer_id, null: false
+    t.integer :project_id, null: false
+    t.date    :joined_on
+    t.integer :access_level, default: 1
+  end
+
+  create_table :dog_lovers, force: true do |t|
+    t.integer :trained_dogs_count, default: 0
+    t.integer :bred_dogs_count, default: 0
+    t.integer :dogs_count, default: 0
+  end
+
+  create_table :dogs, force: true do |t|
+    t.integer :trainer_id
+    t.integer :breeder_id
+    t.integer :dog_lover_id
+    t.string  :alias
+  end
+
+  create_table :edges, force: true, id: false do |t|
+    t.column :source_id, :integer, null: false
+    t.column :sink_id,   :integer, null: false
+  end
+  add_index :edges, [:source_id, :sink_id], unique: true, name: 'unique_edge_index'
+
+  create_table :engines, force: true do |t|
+    t.integer :car_id
+  end
+
+  create_table :entrants, force: true do |t|
+    t.string  :name, null: false
+    t.integer :course_id, null: false
+  end
+
+  create_table :essays, force: true do |t|
+    t.string :name
+    t.string :writer_id
+    t.string :writer_type
+    t.string :category_id
+    t.string :author_id
+  end
+
+  create_table :events, force: true do |t|
+    t.string :title, limit: 5
+  end
+
+  create_table :eyes, force: true do |t|
+  end
+
+  create_table :funny_jokes, force: true do |t|
+    t.string :name
+  end
+
+  create_table :cold_jokes, force: true do |t|
+    t.string :name
+  end
+
+  create_table :friendships, force: true do |t|
+    t.integer :friend_id
+    t.integer :follower_id
+  end
+
+  create_table :goofy_string_id, force: true, id: false do |t|
+    t.string :id, null: false
+    t.string :info
+  end
+
+  create_table :having, force: true do |t|
+    t.string :where
+  end
+
+  create_table :guids, force: true do |t|
+    t.column :key, :string
+  end
+
+  create_table :inept_wizards, force: true do |t|
+    t.column :name, :string, null: false
+    t.column :city, :string, null: false
+    t.column :type, :string
+  end
+
+  create_table :integer_limits, force: true do |t|
+    t.integer :"c_int_without_limit"
+    (1..8).each do |i|
+      t.integer :"c_int_#{i}", limit: i
+    end
+  end
+
+  create_table :invoices, force: true do |t|
+    t.integer :balance
+    t.datetime :updated_at
+  end
+
+  create_table :iris, force: true do |t|
+    t.references :eye
+    t.string     :color
+  end
+
+  create_table :items, force: true do |t|
+    t.column :name, :string
+  end
+
+  create_table :jobs, force: true do |t|
+    t.integer :ideal_reference_id
+  end
+
+  create_table :keyboards, force: true, id: false do |t|
+    t.primary_key :key_number
+    t.string      :name
+  end
+
+  create_table :legacy_things, force: true do |t|
+    t.integer :tps_report_number
+    t.integer :version, null: false, default: 0
+  end
+
+  create_table :lessons, force: true do |t|
+    t.string :name
+  end
+
+  create_table :lessons_students, id: false, force: true do |t|
+    t.references :lesson
+    t.references :student
+  end
+
+  create_table :lint_models, force: true
+
+  create_table :line_items, force: true do |t|
+    t.integer :invoice_id
+    t.integer :amount
+  end
+
+  create_table :lock_without_defaults, force: true do |t|
+    t.column :lock_version, :integer
+  end
+
+  create_table :lock_without_defaults_cust, force: true do |t|
+    t.column :custom_lock_version, :integer
+  end
+
+  create_table :magazines, force: true do |t|
+  end
+
+  create_table :mateys, id: false, force: true do |t|
+    t.column :pirate_id, :integer
+    t.column :target_id, :integer
+    t.column :weight, :integer
+  end
+
+  create_table :members, force: true do |t|
+    t.string :name
+    t.integer :member_type_id
+  end
+
+  create_table :member_details, force: true do |t|
+    t.integer :member_id
+    t.integer :organization_id
+    t.string :extra_data
+  end
+
+  create_table :member_friends, force: true, id: false do |t|
+    t.integer :member_id
+    t.integer :friend_id
+  end
+
+  create_table :memberships, force: true do |t|
+    t.datetime :joined_on
+    t.integer :club_id, :member_id
+    t.boolean :favourite, default: false
+    t.string :type
+  end
+
+  create_table :member_types, force: true do |t|
+    t.string :name
+  end
+
+  create_table :minivans, force: true, id: false do |t|
+    t.string :minivan_id
+    t.string :name
+    t.string :speedometer_id
+    t.string :color
+  end
+
+  create_table :minimalistics, force: true do |t|
+  end
+
+  create_table :mixed_case_monkeys, force: true, id: false do |t|
+    t.primary_key :monkeyID
+    t.integer     :fleaCount
+  end
+
+  create_table :mixins, force: true do |t|
+    t.integer  :parent_id
+    t.integer  :pos
+    t.datetime :created_at
+    t.datetime :updated_at
+    t.integer  :lft
+    t.integer  :rgt
+    t.integer  :root_id
+    t.string   :type
+  end
+
+  create_table :movies, force: true, id: false do |t|
+    t.primary_key :movieid
+    t.string      :name
+  end
+
+  create_table :numeric_data, force: true do |t|
+    t.decimal :bank_balance, precision: 10, scale: 2
+    t.decimal :big_bank_balance, precision: 15, scale: 2
+    t.decimal :world_population, precision: 10, scale: 0
+    t.decimal :my_house_population, precision: 2, scale: 0
+    t.decimal :decimal_number_with_default, precision: 3, scale: 2, default: 2.78
+    t.float   :temperature
+    # Oracle/SQLServer supports precision up to 38
+    if current_adapter?(:OracleAdapter, :SQLServerAdapter)
+      t.decimal :atoms_in_universe, precision: 38, scale: 0
+    else
+      t.decimal :atoms_in_universe, precision: 55, scale: 0
+    end
+  end
+
+  create_table :orders, force: true do |t|
+    t.string  :name
+    t.integer :billing_customer_id
+    t.integer :shipping_customer_id
+  end
+
+  create_table :organizations, force: true do |t|
+    t.string :name
+  end
+
+  create_table :owners, primary_key: :owner_id, force: true do |t|
+    t.string :name
+    t.column :updated_at, :datetime
+    t.column :happy_at,   :datetime
+    t.string :essay_id
+  end
+
+  create_table :paint_colors, force: true do |t|
+    t.integer :non_poly_one_id
+  end
+
+  create_table :paint_textures, force: true do |t|
+    t.integer :non_poly_two_id
+  end
+
+  create_table :parrots, force: true do |t|
+    t.column :name, :string
+    t.column :color, :string
+    t.column :parrot_sti_class, :string
+    t.column :killer_id, :integer
+    t.column :created_at, :datetime
+    t.column :created_on, :datetime
+    t.column :updated_at, :datetime
+    t.column :updated_on, :datetime
+  end
+
+  create_table :parrots_pirates, id: false, force: true do |t|
+    t.column :parrot_id, :integer
+    t.column :pirate_id, :integer
+  end
+
+  create_table :parrots_treasures, id: false, force: true do |t|
+    t.column :parrot_id, :integer
+    t.column :treasure_id, :integer
+  end
+
+  create_table :people, force: true do |t|
+    t.string     :first_name, null: false
+    t.references :primary_contact
+    t.string     :gender, limit: 1
+    t.references :number1_fan
+    t.integer    :lock_version, null: false, default: 0
+    t.string     :comments
+    t.integer    :followers_count, default: 0
+    t.integer    :friends_too_count, default: 0
+    t.references :best_friend
+    t.references :best_friend_of
+    t.integer    :insures, null: false, default: 0
+    t.timestamp :born_at
+    t.timestamps
+  end
+
+  create_table :peoples_treasures, id: false, force: true do |t|
+    t.column :rich_person_id, :integer
+    t.column :treasure_id, :integer
+  end
+
+  create_table :pets, primary_key: :pet_id, force: true do |t|
+    t.string :name
+    t.integer :owner_id, :integer
+    t.timestamps
+  end
+
+  create_table :pirates, force: true do |t|
+    t.column :catchphrase, :string
+    t.column :parrot_id, :integer
+    t.integer :non_validated_parrot_id
+    t.column :created_on, :datetime
+    t.column :updated_on, :datetime
+  end
+
+  create_table :posts, force: true do |t|
+    t.integer :author_id
+    t.string  :title, null: false
+    # use VARCHAR2(4000) instead of CLOB datatype as CLOB data type has many limitations in
+    # Oracle SELECT WHERE clause which causes many unit test failures
+    if current_adapter?(:OracleAdapter)
+      t.string  :body, null: false, limit: 4000
+    else
+      t.text    :body, null: false
+    end
+    t.string  :type
+    t.integer :comments_count, default: 0
+    t.integer :taggings_with_delete_all_count, default: 0
+    t.integer :taggings_with_destroy_count, default: 0
+    t.integer :tags_count, default: 0
+    t.integer :tags_with_destroy_count, default: 0
+    t.integer :tags_with_nullify_count, default: 0
+  end
+
+  create_table :price_estimates, force: true do |t|
+    t.string :estimate_of_type
+    t.integer :estimate_of_id
+    t.integer :price
+  end
+
+  create_table :products, force: true do |t|
+    t.references :collection
+    t.references :type
+    t.string     :name
+  end
+
+  create_table :product_types, force: true do |t|
+    t.string :name
+  end
+
+  create_table :projects, force: true do |t|
+    t.string :name
+    t.string :type
+  end
+
+  create_table :randomly_named_table, force: true do |t|
+    t.string  :some_attribute
+    t.integer :another_attribute
+  end
+
+  create_table :ratings, force: true do |t|
+    t.integer :comment_id
+    t.integer :value
+  end
+
+  create_table :readers, force: true do |t|
+    t.integer :post_id, null: false
+    t.integer :person_id, null: false
+    t.boolean :skimmer, default: false
+    t.integer :first_post_id
+  end
+
+  create_table :references, force: true do |t|
+    t.integer :person_id
+    t.integer :job_id
+    t.boolean :favourite
+    t.integer :lock_version, default: 0
+  end
+
+  create_table :shape_expressions, force: true do |t|
+    t.string  :paint_type
+    t.integer :paint_id
+    t.string  :shape_type
+    t.integer :shape_id
+  end
+
+  create_table :ships, force: true do |t|
+    t.string :name
+    t.integer :pirate_id
+    t.integer :update_only_pirate_id
+    t.datetime :created_at
+    t.datetime :created_on
+    t.datetime :updated_at
+    t.datetime :updated_on
+  end
+
+  create_table :ship_parts, force: true do |t|
+    t.string :name
+    t.integer :ship_id
+  end
+
+  create_table :speedometers, force: true, id: false do |t|
+    t.string :speedometer_id
+    t.string :name
+    t.string :dashboard_id
+  end
+
+  create_table :sponsors, force: true do |t|
+    t.integer :club_id
+    t.integer :sponsorable_id
+    t.string :sponsorable_type
+  end
+
+  create_table :string_key_objects, id: false, primary_key: :id, force: true do |t|
+    t.string     :id
+    t.string     :name
+    t.integer    :lock_version, null: false, default: 0
+  end
+
+  create_table :students, force: true do |t|
+    t.string :name
+    t.boolean :active
+    t.integer :college_id
+  end
+
+  create_table :subscribers, force: true, id: false do |t|
+    t.string :nick, null: false
+    t.string :name
+    t.column :books_count, :integer, null: false, default: 0
+  end
+  add_index :subscribers, :nick, unique: true
+
+  create_table :subscriptions, force: true do |t|
+    t.string :subscriber_id
+    t.integer :book_id
+  end
+
+  create_table :tags, force: true do |t|
+    t.column :name, :string
+    t.column :taggings_count, :integer, default: 0
+  end
+
+  create_table :taggings, force: true do |t|
+    t.column :tag_id, :integer
+    t.column :super_tag_id, :integer
+    t.column :taggable_type, :string
+    t.column :taggable_id, :integer
+    t.string :comment
+  end
+
+  create_table :tasks, force: true do |t|
+    t.datetime :starting
+    t.datetime :ending
+  end
+
+  create_table :topics, force: true do |t|
+    t.string   :title, limit: 250
+    t.string   :author_name
+    t.string   :author_email_address
+    if mysql_56?
+      t.datetime :written_on, limit: 6
+    else
+      t.datetime :written_on
+    end
+    t.time     :bonus_time
+    t.date     :last_read
+    # use VARCHAR2(4000) instead of CLOB datatype as CLOB data type has many limitations in
+    # Oracle SELECT WHERE clause which causes many unit test failures
+    if current_adapter?(:OracleAdapter)
+      t.string   :content, limit: 4000
+      t.string   :important, limit: 4000
+    else
+      t.text     :content
+      t.text     :important
+    end
+    t.boolean  :approved, default: true
+    t.integer  :replies_count, default: 0
+    t.integer  :unique_replies_count, default: 0
+    t.integer  :parent_id
+    t.string   :parent_title
+    t.string   :type
+    t.string   :group
+    t.timestamps
+  end
+
+  create_table :toys, primary_key: :toy_id, force: true do |t|
+    t.string :name
+    t.integer :pet_id, :integer
+    t.timestamps
+  end
+
+  create_table :traffic_lights, force: true do |t|
+    t.string   :location
+    t.string   :state
+    t.text     :long_state, null: false
+    t.datetime :created_at
+    t.datetime :updated_at
+  end
+
+  create_table :treasures, force: true do |t|
+    t.column :name, :string
+    t.column :type, :string
+    t.column :looter_id, :integer
+    t.column :looter_type, :string
+  end
+
+  create_table :tyres, force: true do |t|
+    t.integer :car_id
+  end
+
+  create_table :variants, force: true do |t|
+    t.references :product
+    t.string     :name
+  end
+
+  create_table :vertices, force: true do |t|
+    t.column :label, :string
+  end
+
+  create_table 'warehouse-things', force: true do |t|
+    t.integer :value
+  end
+
+  [:circles, :squares, :triangles, :non_poly_ones, :non_poly_twos].each do |t|
+    create_table(t, force: true) { }
+  end
+
+  # NOTE - the following 4 tables are used by models that have :inverse_of options on the associations
+  create_table :men, force: true do |t|
+    t.string  :name
+  end
+
+  create_table :faces, force: true do |t|
+    t.string  :description
+    t.integer :man_id
+    t.integer :polymorphic_man_id
+    t.string  :polymorphic_man_type
+    t.integer :poly_man_without_inverse_id
+    t.string  :poly_man_without_inverse_type
+    t.integer :horrible_polymorphic_man_id
+    t.string  :horrible_polymorphic_man_type
+  end
+
+  create_table :interests, force: true do |t|
+    t.string :topic
+    t.integer :man_id
+    t.integer :polymorphic_man_id
+    t.string :polymorphic_man_type
+    t.integer :zine_id
+  end
+
+  create_table :wheels, force: true do |t|
+    t.references :wheelable, polymorphic: true
+  end
+
+  create_table :zines, force: true do |t|
+    t.string :title
+  end
+
+  create_table :countries, force: true, id: false, primary_key: 'country_id' do |t|
+    t.string :country_id
+    t.string :name
+  end
+  create_table :treaties, force: true, id: false, primary_key: 'treaty_id' do |t|
+    t.string :treaty_id
+    t.string :name
+  end
+  create_table :countries_treaties, force: true, id: false do |t|
+    t.string :country_id, null: false
+    t.string :treaty_id, null: false
+  end
+
+  create_table :liquid, force: true do |t|
+    t.string :name
+  end
+  create_table :molecules, force: true do |t|
+    t.integer :liquid_id
+    t.string :name
+  end
+  create_table :electrons, force: true do |t|
+    t.integer :molecule_id
+    t.string :name
+  end
+  create_table :weirds, force: true do |t|
+    t.string 'a$b'
+    t.string 'なまえ'
+    t.string 'from'
+  end
+
+  create_table :hotels, force: true do |t|
+  end
+  create_table :departments, force: true do |t|
+    t.integer :hotel_id
+  end
+  create_table :cake_designers, force: true do |t|
+  end
+  create_table :drink_designers, force: true do |t|
+  end
+  create_table :chefs, force: true do |t|
+    t.integer :employable_id
+    t.string :employable_type
+    t.integer :department_id
+  end
+
+  create_table :records, force: true do |t|
+  end
+
+  except 'SQLite' do
+    # fk_test_has_fk should be before fk_test_has_pk
+    create_table :fk_test_has_fk, force: true do |t|
+      t.integer :fk_id, null: false
+    end
+
+    create_table :fk_test_has_pk, force: true, primary_key: "pk_id" do |t|
+    end
+
+    add_foreign_key :fk_test_has_fk, :fk_test_has_pk, column: "fk_id", name: "fk_name", primary_key: "pk_id"
+    add_foreign_key :lessons_students, :students
+  end
+
+  create_table :overloaded_types, force: true do |t|
+    t.float :overloaded_float, default: 500
+    t.float :unoverloaded_float
+    t.string :overloaded_string_with_limit, limit: 255
+    t.string :string_with_default, default: 'the original default'
+  end
+end
+
+Course.connection.create_table :courses, force: true do |t|
+  t.column :name, :string, null: false
+  t.column :college_id, :integer
+end
+
+College.connection.create_table :colleges, force: true do |t|
+  t.column :name, :string, null: false
+end
diff --git a/activerecord/test/schema/sqlite_specific_schema.rb b/activerecord/test/schema/sqlite_specific_schema.rb
new file mode 100644
index 0000000000..b5552c2755
--- /dev/null
+++ b/activerecord/test/schema/sqlite_specific_schema.rb
@@ -0,0 +1,22 @@
+ActiveRecord::Schema.define do
+  create_table :table_with_autoincrement, :force => true do |t|
+    t.column :name, :string
+  end
+
+  execute "DROP TABLE fk_test_has_fk" rescue nil
+  execute "DROP TABLE fk_test_has_pk" rescue nil
+  execute <<_SQL
+  CREATE TABLE 'fk_test_has_pk' (
+    'pk_id' INTEGER NOT NULL PRIMARY KEY
+  );
+_SQL
+
+  execute <<_SQL
+  CREATE TABLE 'fk_test_has_fk' (
+    'id'    INTEGER NOT NULL PRIMARY KEY,
+    'fk_id' INTEGER NOT NULL,
+
+    FOREIGN KEY ('fk_id') REFERENCES 'fk_test_has_pk'('pk_id')
+  );
+_SQL
+end
diff --git a/activerecord/test/support/config.rb b/activerecord/test/support/config.rb
new file mode 100644
index 0000000000..6d123688a3
--- /dev/null
+++ b/activerecord/test/support/config.rb
@@ -0,0 +1,43 @@
+require 'yaml'
+require 'erubis'
+require 'fileutils'
+require 'pathname'
+
+module ARTest
+  class << self
+    def config
+      @config ||= read_config
+    end
+
+    private
+
+    def config_file
+      Pathname.new(ENV['ARCONFIG'] || TEST_ROOT + '/config.yml')
+    end
+
+    def read_config
+      unless config_file.exist?
+        FileUtils.cp TEST_ROOT + '/config.example.yml', config_file
+      end
+
+      erb = Erubis::Eruby.new(config_file.read)
+      expand_config(YAML.parse(erb.result(binding)).transform)
+    end
+
+    def expand_config(config)
+      config['connections'].each do |adapter, connection|
+        dbs = [['arunit', 'activerecord_unittest'], ['arunit2', 'activerecord_unittest2']]
+        dbs.each do |name, dbname|
+          unless connection[name].is_a?(Hash)
+            connection[name] = { 'database' => connection[name] }
+          end
+
+          connection[name]['database'] ||= dbname
+          connection[name]['adapter']  ||= adapter
+        end
+      end
+
+      config
+    end
+  end
+end
diff --git a/activerecord/test/support/connection.rb b/activerecord/test/support/connection.rb
new file mode 100644
index 0000000000..d11fd9cfc1
--- /dev/null
+++ b/activerecord/test/support/connection.rb
@@ -0,0 +1,21 @@
+require 'active_support/logger'
+require 'models/college'
+require 'models/course'
+
+module ARTest
+  def self.connection_name
+    ENV['ARCONN'] || config['default_connection']
+  end
+
+  def self.connection_config
+    config['connections'][connection_name]
+  end
+
+  def self.connect
+    puts "Using #{connection_name}"
+    ActiveRecord::Base.logger = ActiveSupport::Logger.new("debug.log", 0, 100 * 1024 * 1024)
+    ActiveRecord::Base.configurations = connection_config
+    ActiveRecord::Base.establish_connection :arunit
+    ARUnit2Model.establish_connection :arunit2
+  end
+end
diff --git a/activerecord/test/support/connection_helper.rb b/activerecord/test/support/connection_helper.rb
new file mode 100644
index 0000000000..4a19e5df44
--- /dev/null
+++ b/activerecord/test/support/connection_helper.rb
@@ -0,0 +1,14 @@
+module ConnectionHelper
+  def run_without_connection
+    original_connection = ActiveRecord::Base.remove_connection
+    yield original_connection
+  ensure
+    ActiveRecord::Base.establish_connection(original_connection)
+  end
+
+  # Used to drop all cache query plans in tests.
+  def reset_connection
+    original_connection = ActiveRecord::Base.remove_connection
+    ActiveRecord::Base.establish_connection(original_connection)
+  end
+end
diff --git a/activerecord/test/support/ddl_helper.rb b/activerecord/test/support/ddl_helper.rb
new file mode 100644
index 0000000000..43cb235e01
--- /dev/null
+++ b/activerecord/test/support/ddl_helper.rb
@@ -0,0 +1,8 @@
+module DdlHelper
+  def with_example_table(connection, table_name, definition = nil)
+    connection.execute("CREATE TABLE #{table_name}(#{definition})")
+    yield
+  ensure
+    connection.execute("DROP TABLE #{table_name}")
+  end
+end
diff --git a/activerecord/test/support/schema_dumping_helper.rb b/activerecord/test/support/schema_dumping_helper.rb
new file mode 100644
index 0000000000..2ae8d299e5
--- /dev/null
+++ b/activerecord/test/support/schema_dumping_helper.rb
@@ -0,0 +1,11 @@
+module SchemaDumpingHelper
+  def dump_table_schema(table, connection = ActiveRecord::Base.connection)
+    old_ignore_tables = ActiveRecord::SchemaDumper.ignore_tables
+    ActiveRecord::SchemaDumper.ignore_tables = connection.tables - [table]
+    stream = StringIO.new
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    stream.string
+  ensure
+    ActiveRecord::SchemaDumper.ignore_tables = old_ignore_tables
+  end
+end