Merge branch 'master' into nested_has_many_through

Conflicts:
	activerecord/CHANGELOG
	activerecord/lib/active_record/association_preload.rb
	activerecord/lib/active_record/associations.rb
	activerecord/lib/active_record/associations/class_methods/join_dependency.rb
	activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
	activerecord/lib/active_record/associations/has_many_association.rb
	activerecord/lib/active_record/associations/has_many_through_association.rb
	activerecord/lib/active_record/associations/has_one_association.rb
	activerecord/lib/active_record/associations/has_one_through_association.rb
	activerecord/lib/active_record/associations/through_association_scope.rb
	activerecord/lib/active_record/reflection.rb
	activerecord/test/cases/associations/has_many_through_associations_test.rb
	activerecord/test/cases/associations/has_one_through_associations_test.rb
	activerecord/test/cases/reflection_test.rb
	activerecord/test/cases/relations_test.rb
	activerecord/test/fixtures/memberships.yml
	activerecord/test/models/categorization.rb
	activerecord/test/models/category.rb
	activerecord/test/models/member.rb
	activerecord/test/models/reference.rb
	activerecord/test/models/tagging.rb

207 files changed, 9286 insertions, 5362 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 2d9f4da79e..3a63c08b2d 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,8 +1,172 @@
 *Rails 3.1.0 (unreleased)*
 
 * Associations with a :through option can now use *any* association as the
-through or source association, including other associations which have a
-:through option and has_and_belongs_to_many associations #1812 [Jon Leighton]
+  through or source association, including other associations which have a
+  :through option and has_and_belongs_to_many associations
+
+  [Jon Leighton]
+
+* limits and offsets are removed from COUNT queries unless both are supplied.
+  For example:
+
+    People.limit(1).count           # => 'SELECT COUNT(*) FROM people'
+    People.offset(1).count          # => 'SELECT COUNT(*) FROM people'
+    People.limit(1).offset(1).count # => 'SELECT COUNT(*) FROM people LIMIT 1 OFFSET 1'
+
+  [lighthouse #6262]
+
+* ActiveRecord::Associations::AssociationProxy has been split. There is now an Association class
+  (and subclasses) which are responsible for operating on associations, and then a separate,
+  thin wrapper called CollectionProxy, which proxies collection associations.
+
+  This prevents namespace pollution, separates concerns, and will allow further refactorings.
+
+  Singular associations (has_one, belongs_to) no longer have a proxy at all. They simply return
+  the associated record or nil. This means that you should not use undocumented methods such
+  as bob.mother.create - use bob.create_mother instead.
+
+  [Jon Leighton]
+
+* Make has_many :through associations work correctly when you build a record and then save it. This
+  requires you to set the :inverse_of option on the source reflection on the join model, like so:
+
+  class Post < ActiveRecord::Base
+    has_many :taggings
+    has_many :tags, :through => :taggings
+  end
+
+  class Tagging < ActiveRecord::Base
+    belongs_to :post
+    belongs_to :tag, :inverse_of => :tagging # :inverse_of must be set!
+  end
+
+  class Tag < ActiveRecord::Base
+    has_many :taggings
+    has_many :posts, :through => :taggings
+  end
+
+  post = Post.first
+  tag = post.tags.build :name => "ruby"
+  tag.save # will save a Taggable linking to the post
+
+  [Jon Leighton]
+
+* Support the :dependent option on has_many :through associations. For historical and practical
+  reasons, :delete_all is the default deletion strategy employed by association.delete(*records),
+  despite the fact that the default strategy is :nullify for regular has_many. Also, this only
+  works at all if the source reflection is a belongs_to. For other situations, you should directly
+  modify the through association.
+
+  [Jon Leighton]
+
+* Changed the behaviour of association.destroy for has_and_belongs_to_many and has_many :through.
+  From now on, 'destroy' or 'delete' on an association will be taken to mean 'get rid of the link',
+  not (necessarily) 'get rid of the associated records'.
+
+  Previously, has_and_belongs_to_many.destroy(*records) would destroy the records themselves. It
+  would not delete any records in the join table. Now, it deletes the records in the join table.
+
+  Previously, has_many_through.destroy(*records) would destroy the records themselves, and the
+  records in the join table. [Note: This has not always been the case; previous version of Rails
+  only deleted the records themselves.] Now, it destroys only the records in the join table.
+
+  Note that this change is backwards-incompatible to an extent, but there is unfortunately no
+  way to 'deprecate' it before changing it. The change is being made in order to have
+  consistency as to the meaning of 'destroy' or 'delete' across the different types of associations.
+
+  If you wish to destroy the records themselves, you can do records.association.each(&:destroy)
+
+  [Jon Leighton]
+
+* Add :bulk => true option to change_table to make all the schema changes defined in change_table block using a single ALTER statement. [Pratik Naik]
+
+  Example:
+
+  change_table(:users, :bulk => true) do |t|
+    t.string :company_name
+    t.change :birthdate, :datetime
+  end
+
+  This will now result in:
+
+    ALTER TABLE `users` ADD COLUMN `company_name` varchar(255), CHANGE `updated_at` `updated_at` datetime DEFAULT NULL
+
+* Removed support for accessing attributes on a has_and_belongs_to_many join table. This has been
+  documented as deprecated behaviour since April 2006. Please use has_many :through instead.
+  [Jon Leighton]
+
+* Added a create_association! method for has_one and belongs_to associations. [Jon Leighton]
+
+* Migration files generated from model and constructive migration generators
+  (for example, add_name_to_users) use the reversible migration's `change`
+  method instead of the ordinary `up` and `down` methods. [Prem Sichanugrist]
+
+* Removed support for interpolating string SQL conditions on associations. Instead, you should
+  use a proc, like so:
+
+  Before:
+
+    has_many :things, :conditions => 'foo = #{bar}'
+
+  After:
+
+    has_many :things, :conditions => proc { "foo = #{bar}" }
+
+  Inside the proc, 'self' is the object which is the owner of the association, unless you are
+  eager loading the association, in which case 'self' is the class which the association is within.
+
+  You can have any "normal" conditions inside the proc, so the following will work too:
+
+    has_many :things, :conditions => proc { ["foo = ?", bar] }
+
+  Previously :insert_sql and :delete_sql on has_and_belongs_to_many association allowed you to call
+  'record' to get the record being inserted or deleted. This is now passed as an argument to
+  the proc.
+
+* Added ActiveRecord::Base#has_secure_password (via ActiveModel::SecurePassword) to encapsulate dead-simple password usage with BCrypt encryption and salting [DHH]. Example:
+
+    # Schema: User(name:string, password_digest:string, password_salt:string)
+    class User < ActiveRecord::Base
+      has_secure_password
+    end
+
+    user = User.new(:name => "david", :password => "", :password_confirmation => "nomatch")
+    user.save                                                      # => false, password required
+    user.password = "mUc3m00RsqyRe"
+    user.save                                                      # => false, confirmation doesn't match
+    user.password_confirmation = "mUc3m00RsqyRe"
+    user.save                                                      # => true
+    user.authenticate("notright")                                  # => false
+    user.authenticate("mUc3m00RsqyRe")                             # => user
+    User.find_by_name("david").try(:authenticate, "notright")      # => nil
+    User.find_by_name("david").try(:authenticate, "mUc3m00RsqyRe") # => user
+
+
+* When a model is generated add_index is added by default for belongs_to or references columns
+
+  rails g model post user:belongs_to will generate the following:
+
+    class CreatePosts < ActiveRecord::Migration
+      def up
+        create_table :posts do |t|
+          t.belongs_to :user
+
+          t.timestamps
+        end
+
+        add_index :posts, :user_id
+      end
+
+      def down
+        drop_table :posts
+      end
+    end
+
+  [Santiago Pastorino]
+<<<<<<< Updated upstream
+>>>>>>> association_fixes
+=======
+>>>>>>> Stashed changes
 
 * Setting the id of a belongs_to object will update the reference to the
 object. [#2989 state:resolved]
@@ -63,7 +227,15 @@ IrreversibleMigration exception will be raised when going down.
 
   [Aaron Patterson]
 
-*Rails 3.0.2 (unreleased)*
+
+*Rails 3.0.3 (November 16, 2010)*
+
+* Support find by class like this: Post.where(:name => Post)
+
+
+*Rails 3.0.2 (November 15, 2010)*
+
+* Dramatic speed increase (see: http://engineering.attinteractive.com/2010/10/arel-two-point-ohhhhh-yaaaaaa/) [Aaron Patterson]
 
 * reorder is deprecated in favor of except(:order).order(...) [Santiago Pastorino]
 
diff --git a/activerecord/MIT-LICENSE b/activerecord/MIT-LICENSE
index 86bcb23b7c..c73d1af096 100644
--- a/activerecord/MIT-LICENSE
+++ b/activerecord/MIT-LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2004-2010 David Heinemeier Hansson
+Copyright (c) 2004-2011 David Heinemeier Hansson
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
diff --git a/activerecord/README.rdoc b/activerecord/README.rdoc
index 101a595ecd..91a23da8ad 100644
--- a/activerecord/README.rdoc
+++ b/activerecord/README.rdoc
@@ -84,7 +84,7 @@ A short rundown of some of the major features:
 
    class CommentObserver < ActiveRecord::Observer
      def after_create(comment) # is called just after Comment#save
-       Notifications.deliver_new_comment("david@loudthinking.com", comment)
+       CommentMailer.new_comment_email("david@loudthinking.com", comment)
      end
    end
 
@@ -128,7 +128,7 @@ A short rundown of some of the major features:
 
     # connect to MySQL with authentication
     ActiveRecord::Base.establish_connection(
-      :adapter  => "mysql",
+      :adapter  => "mysql2",
       :host     => "localhost",
       :username => "me",
       :password => "secret",
diff --git a/activerecord/RUNNING_UNIT_TESTS b/activerecord/RUNNING_UNIT_TESTS
index 18e3936d8a..b3d376772e 100644
--- a/activerecord/RUNNING_UNIT_TESTS
+++ b/activerecord/RUNNING_UNIT_TESTS
@@ -1,8 +1,8 @@
 == Creating the test database
 
 The default names for the test databases are "activerecord_unittest" and
-"activerecord_unittest2". If you want to use another database name then be sure
-to update the connection adapter setups you want to test with in
+"activerecord_unittest2". If you want to use another database name, then be sure
+to update the connection adapter setups you want to test within
 test/connections/<your database>/connection.rb.
 When you have the database online, you can import the fixture tables with
 the test/schema/*.sql files.
@@ -32,7 +32,7 @@ being initialized - you can initialize the schema with:
 
   rake test_mysql TEST=test/cases/aaa_create_tables_test.rb
   rake mysql:build_databases
-  
+
 To setup the testing environment for PostgreSQL use this command:
 
   rake postgresql:build_databases
diff --git a/activerecord/Rakefile b/activerecord/Rakefile
index f9b77c1799..e414c4fb1c 100755
--- a/activerecord/Rakefile
+++ b/activerecord/Rakefile
@@ -41,7 +41,7 @@ namespace :test do
   end
 end
 
-%w( mysql mysql2 postgresql sqlite3 firebird db2 oracle sybase openbase frontbase jdbcmysql jdbcpostgresql jdbcsqlite3 jdbcderby jdbch2 jdbchsqldb ).each do |adapter|
+%w( mysql mysql2 postgresql sqlite3 sqlite3_mem firebird db2 oracle sybase openbase frontbase jdbcmysql jdbcpostgresql jdbcsqlite3 jdbcderby jdbch2 jdbchsqldb ).each do |adapter|
   Rake::TestTask.new("test_#{adapter}") { |t|
     connection_path = "test/connections/#{adapter =~ /jdbc/ ? 'jdbc' : 'native'}_#{adapter}"
     adapter_short = adapter == 'db2' ? adapter : adapter[/^[a-z0-9]+/]
@@ -62,7 +62,7 @@ end
     (Dir["test/cases/**/*_test.rb"].reject {
       |x| x =~ /\/adapters\//
     } + Dir["test/cases/adapters/#{adapter_short}/**/*_test.rb"]).all? do |file|
-      system(ruby, "-Ilib:test:#{connection_path}", file)
+      sh(ruby, "-Ilib:test:#{connection_path}", file)
     end or raise "Failures"
   end
 
@@ -72,6 +72,15 @@ end
   end
 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 :mysql do
   desc 'Build the MySQL test databases'
   task :build_databases do
diff --git a/activerecord/examples/performance.rb b/activerecord/examples/performance.rb
index c4ce361b5d..63822731d5 100644
--- a/activerecord/examples/performance.rb
+++ b/activerecord/examples/performance.rb
@@ -1,31 +1,9 @@
-#!/usr/bin/env ruby -KU
-
 TIMES = (ENV['N'] || 10000).to_i
-require 'rubygems'
-
-gem 'addressable',  '~>2.0'
-gem 'faker',        '~>0.3.1'
-gem 'rbench',       '~>0.2.3'
 
-require 'addressable/uri'
-require 'faker'
-require 'rbench'
-
-require File.expand_path("../../../load_paths", __FILE__)
+require 'rubygems'
 require "active_record"
 
-conn = { :adapter => 'mysql',
-  :database => 'activerecord_unittest',
-  :username => 'rails', :password => '',
-  :encoding => 'utf8' }
-
-conn[:socket] = Pathname.glob(%w[
-  /opt/local/var/run/mysql5/mysqld.sock
-  /tmp/mysqld.sock
-  /tmp/mysql.sock
-  /var/mysql/mysql.sock
-  /var/run/mysqld/mysqld.sock
-]).find { |path| path.socket? }.to_s
+conn = { :adapter => 'sqlite3', :database => ':memory:' }
 
 ActiveRecord::Base.establish_connection(conn)
 
@@ -55,125 +33,126 @@ class Exhibit < ActiveRecord::Base
   def self.feel(exhibits) exhibits.each { |e| e.feel } end
 end
 
-sqlfile = File.expand_path("../performance.sql", __FILE__)
-
-if File.exists?(sqlfile)
-  mysql_bin = %w[mysql mysql5].detect { |bin| `which #{bin}`.length > 0 }
-  `#{mysql_bin} -u #{conn[:username]} #{"-p#{conn[:password]}" unless conn[:password].blank?} #{conn[:database]} < #{sqlfile}`
-else
-  puts 'Generating data...'
-
-  # 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 = Faker::Lorem.paragraphs.join($/)
-  today = Date.today
-
-  puts 'Inserting 10,000 users and exhibits...'
-  10_000.times do
-    user = User.create(
-      :created_at => today,
-      :name       => Faker::Name.name,
-      :email      => Faker::Internet.email
-    )
-
-    Exhibit.create(
-      :created_at => today,
-      :name       => Faker::Company.name,
-      :user       => user,
-      :notes      => notes
-    )
-  end
-
-  mysqldump_bin = %w[mysqldump mysqldump5].detect { |bin| `which #{bin}`.length > 0 }
-  `#{mysqldump_bin} -u #{conn[:username]} #{"-p#{conn[:password]}" unless conn[:password].blank?} #{conn[:database]} exhibits users > #{sqlfile}`
+puts 'Generating data...'
+
+module ActiveRecord
+  class Faker
+    LOREM = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse non aliquet diam. Curabitur vel urna metus, quis malesuada elit. Integer consequat tincidunt felis. Etiam non erat dolor. Vivamus imperdiet nibh sit amet diam eleifend id posuere diam malesuada. Mauris at accumsan sem. Donec id lorem neque. Fusce erat lorem, ornare eu congue vitae, malesuada quis neque. Maecenas vel urna a velit pretium fermentum. Donec tortor enim, tempor venenatis egestas a, tempor sed ipsum. Ut arcu justo, faucibus non imperdiet ac, interdum at diam. Pellentesque ipsum enim, venenatis ut iaculis vitae, varius vitae sem. Sed rutrum quam ac elit euismod bibendum. Donec ultricies ultricies magna, at lacinia libero mollis aliquam. Sed ac arcu in tortor elementum tincidunt vel interdum sem. Curabitur eget erat arcu. Praesent eget eros leo. Nam magna enim, sollicitudin vehicula scelerisque in, vulputate ut libero. Praesent varius tincidunt commodo".split
+    def self.name
+      LOREM.grep(/^\w*$/).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 10,000 users and exhibits...'
+10_000.times do
+  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
+  )
 end
 
-RBench.run(TIMES) do
-  column :times
-  column :ar
+require 'benchmark'
 
-  report 'Model#id', (TIMES * 100).ceil do
-    ar_obj = Exhibit.find(1)
+Benchmark.bm(46) 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
+  }
 
-    ar { ar_obj.id }
+  x.report("Model#id (x#{(TIMES * 100).ceil})") do
+    (TIMES * 100).ceil.times { ar_obj.id }
   end
 
-  report 'Model.new (instantiation)' do
-    ar { Exhibit.new }
+  x.report 'Model.new (instantiation)' do
+    TIMES.times { Exhibit.new }
   end
 
-  report 'Model.new (setting attributes)' do
-    attrs = { :name => 'sam' }
-    ar { Exhibit.new(attrs) }
+  x.report 'Model.new (setting attributes)' do
+    TIMES.times { Exhibit.new(attrs) }
   end
 
-  report 'Model.first' do
-    ar { Exhibit.first.look }
+  x.report 'Model.first' do
+    TIMES.times { Exhibit.first.look }
   end
 
-  report 'Model.all limit(100)', (TIMES / 10).ceil do
-    ar { Exhibit.look Exhibit.limit(100) }
+  x.report("Model.all limit(100) (x#{(TIMES / 10).ceil})") do
+    (TIMES / 10).ceil.times { Exhibit.look Exhibit.limit(100) }
   end
 
-  report 'Model.all limit(100) with relationship', (TIMES / 10).ceil do
-    ar { Exhibit.feel Exhibit.limit(100).includes(:user) }
+  x.report "Model.all limit(100) with relationship (x#{(TIMES / 10).ceil})" do
+    (TIMES / 10).ceil.times { Exhibit.feel Exhibit.limit(100).includes(:user) }
   end
 
-  report 'Model.all limit(10,000)', (TIMES / 1000).ceil do
-    ar { Exhibit.look Exhibit.limit(10000) }
+  x.report "Model.all limit(10,000) x(#{(TIMES / 1000).ceil})" do
+    (TIMES / 1000).ceil.times { Exhibit.look Exhibit.limit(10000) }
   end
 
-  exhibit = {
-    :name       => Faker::Company.name,
-    :notes      => Faker::Lorem.paragraphs.join($/),
-    :created_at => Date.today
-  }
-
-  report 'Model.create' do
-    ar { Exhibit.create(exhibit) }
+  x.report 'Model.create' do
+    TIMES.times { Exhibit.create(exhibit) }
   end
 
-  report 'Resource#attributes=' do
-    attrs_first  = { :name => 'sam' }
-    attrs_second = { :name => 'tom' }
-    ar { exhibit = Exhibit.new(attrs_first); exhibit.attributes = attrs_second }
+  x.report 'Resource#attributes=' do
+    TIMES.times {
+      exhibit = Exhibit.new(attrs_first)
+      exhibit.attributes = attrs_second
+    }
   end
 
-  report 'Resource#update' do
-    ar { Exhibit.first.update_attributes(:name => 'bob') }
+  x.report 'Resource#update' do
+    TIMES.times { Exhibit.first.update_attributes(:name => 'bob') }
   end
 
-  report 'Resource#destroy' do
-    ar { Exhibit.first.destroy }
+  x.report 'Resource#destroy' do
+    TIMES.times { Exhibit.first.destroy }
   end
 
-  report 'Model.transaction' do
-    ar { Exhibit.transaction { Exhibit.new } }
+  x.report 'Model.transaction' do
+    TIMES.times { Exhibit.transaction { Exhibit.new } }
   end
 
-  report 'Model.find(id)' do
+  x.report 'Model.find(id)' do
     id = Exhibit.first.id
-    ar { Exhibit.find(id) }
+    TIMES.times { Exhibit.find(id) }
   end
 
-  report 'Model.find_by_sql' do
-    ar { Exhibit.find_by_sql("SELECT * FROM exhibits WHERE id = #{(rand * 1000 + 1).to_i}").first }
+  x.report 'Model.find_by_sql' do
+    TIMES.times {
+      Exhibit.find_by_sql("SELECT * FROM exhibits WHERE id = #{(rand * 1000 + 1).to_i}").first
+    }
   end
 
-  report 'Model.log', (TIMES * 10) do
-    ar { Exhibit.connection.send(:log, "hello", "world") {} }
+  x.report "Model.log x(#{TIMES * 10})" do
+    (TIMES * 10).times { Exhibit.connection.send(:log, "hello", "world") {} }
   end
 
-  report 'AR.execute(query)', (TIMES / 2) do
-    ar { ActiveRecord::Base.connection.execute("Select * from exhibits where id = #{(rand * 1000 + 1).to_i}") }
+  x.report "AR.execute(query) (#{TIMES / 2})" do
+    (TIMES / 2).times { ActiveRecord::Base.connection.execute("Select * from exhibits where id = #{(rand * 1000 + 1).to_i}") }
   end
-
-  summary 'Total'
 end
-
-ActiveRecord::Migration.drop_table "exhibits"
-ActiveRecord::Migration.drop_table "users"
diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index c80bce2849..59cf42a377 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -1,5 +1,5 @@
 #--
-# Copyright (c) 2004-2010 David Heinemeier Hansson
+# Copyright (c) 2004-2011 David Heinemeier Hansson
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -43,7 +43,6 @@ module ActiveRecord
     autoload :ConnectionNotEstablished, 'active_record/errors'
 
     autoload :Aggregations
-    autoload :AssociationPreload
     autoload :Associations
     autoload :AttributeMethods
     autoload :AutosaveAssociation
@@ -79,6 +78,11 @@ module ActiveRecord
     autoload :Timestamp
     autoload :Transactions
     autoload :Validations
+    autoload :IdentityMap
+  end
+
+  module Coders
+    autoload :YAMLColumn, 'active_record/coders/yaml_column'
   end
 
   module AttributeMethods
diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
index 8cd7389005..90d3b58c78 100644
--- a/activerecord/lib/active_record/aggregations.rb
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -4,9 +4,7 @@ module ActiveRecord
     extend ActiveSupport::Concern
 
     def clear_aggregation_cache #:nodoc:
-      self.class.reflect_on_all_aggregations.to_a.each do |assoc|
-        instance_variable_set "@#{assoc.name}", nil
-      end if self.persisted?
+      @aggregation_cache.clear if persisted?
     end
 
     # Active Record implements aggregation through a macro-like class method called +composed_of+
@@ -222,53 +220,32 @@ module ActiveRecord
 
       private
         def reader_method(name, class_name, mapping, allow_nil, constructor)
-          module_eval do
-            define_method(name) do |*args|
-              force_reload = args.first || false
-
-              unless instance_variable_defined?("@#{name}")
-                instance_variable_set("@#{name}", nil)
-              end
-
-              if (instance_variable_get("@#{name}").nil? || force_reload) && (!allow_nil || mapping.any? {|pair| !read_attribute(pair.first).nil? })
-                attrs = mapping.collect {|pair| read_attribute(pair.first)}
-                object = case constructor
-                  when Symbol
-                    class_name.constantize.send(constructor, *attrs)
-                  when Proc, Method
-                    constructor.call(*attrs)
-                  else
-                    raise ArgumentError, 'Constructor must be a symbol denoting the constructor method to call or a Proc to be invoked.'
-                  end
-                instance_variable_set("@#{name}", object)
-              end
-              instance_variable_get("@#{name}")
+          define_method(name) do
+            if @aggregation_cache[name].nil? && (!allow_nil || mapping.any? {|pair| !read_attribute(pair.first).nil? })
+              attrs = mapping.collect {|pair| read_attribute(pair.first)}
+              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)
-          module_eval do
-            define_method("#{name}=") do |part|
-              if part.nil? && allow_nil
-                mapping.each { |pair| self[pair.first] = nil }
-                instance_variable_set("@#{name}", nil)
-              else
-                unless part.is_a?(class_name.constantize) || converter.nil?
-                  part = case converter
-                    when Symbol
-                     class_name.constantize.send(converter, part)
-                    when Proc, Method
-                      converter.call(part)
-                    else
-                      raise ArgumentError, 'Converter must be a symbol denoting the converter method to call or a Proc to be invoked.'
-                    end
-                end
-
-                mapping.each { |pair| self[pair.first] = part.send(pair.last) }
-                instance_variable_set("@#{name}", part.freeze)
+          define_method("#{name}=") do |part|
+            if part.nil? && allow_nil
+              mapping.each { |pair| self[pair.first] = nil }
+              @aggregation_cache[name] = nil
+            else
+              unless part.is_a?(class_name.constantize) || converter.nil?
+                part = converter.respond_to?(:call) ?
+                  converter.call(part) :
+                  class_name.constantize.send(converter, part)
               end
+
+              mapping.each { |pair| self[pair.first] = part.send(pair.last) }
+              @aggregation_cache[name] = part.freeze
             end
           end
         end
diff --git a/activerecord/lib/active_record/association_preload.rb b/activerecord/lib/active_record/association_preload.rb
deleted file mode 100644
index 8ca83a7e75..0000000000
--- a/activerecord/lib/active_record/association_preload.rb
+++ /dev/null
@@ -1,421 +0,0 @@
-require 'active_support/core_ext/array/wrap'
-require 'active_support/core_ext/enumerable'
-
-module ActiveRecord
-  # See ActiveRecord::AssociationPreload::ClassMethods for documentation.
-  module AssociationPreload #:nodoc:
-    extend ActiveSupport::Concern
-
-    # Implements the details of eager loading of Active Record associations.
-    # Application developers should not use this module directly.
-    #
-    # <tt>ActiveRecord::Base</tt> is extended with this module. The source code in
-    # <tt>ActiveRecord::Base</tt> references methods defined in this module.
-    #
-    # 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.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.
-    #
-    # See also ActiveRecord::Associations::ClassMethods, which explains eager
-    # loading in a more high-level (application developer-friendly) manner.
-    module ClassMethods
-      protected
-
-      # 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 } ]
-      #
-      # +preload_options+ contains options that will be passed to ActiveRecord::Base#find
-      # (which is called under the hood for preloading records). But it is passed
-      # only one level deep in the +associations+ argument, i.e. it's not passed
-      # to the child associations when +associations+ is a Hash.
-      def preload_associations(records, associations, preload_options={})
-        records = Array.wrap(records).compact.uniq
-        return if records.empty?
-        case associations
-        when Array then associations.each {|association| preload_associations(records, association, preload_options)}
-        when Symbol, String then preload_one_association(records, associations.to_sym, preload_options)
-        when Hash then
-          associations.each do |parent, child|
-            raise "parent must be an association name" unless parent.is_a?(String) || parent.is_a?(Symbol)
-            preload_associations(records, parent, preload_options)
-            reflection = reflections[parent]
-            parents = records.sum { |record| Array.wrap(record.send(reflection.name)) }
-            unless parents.empty?
-              parents.first.class.preload_associations(parents, child)
-            end
-          end
-        end
-      end
-
-      private
-
-      # Preloads a specific named association for the given records. This is
-      # called by +preload_associations+ as its base case.
-      def preload_one_association(records, association, preload_options={})
-        class_to_reflection = {}
-        # 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
-        records.group_by { |record| class_to_reflection[record.class] ||= record.class.reflections[association]}.each do |reflection, _records|
-          raise ConfigurationError, "Association named '#{ association }' was not found; perhaps you misspelled it?" unless reflection
-
-          # 'reflection.macro' can return 'belongs_to', 'has_many', etc. Thus,
-          # the following could call 'preload_belongs_to_association',
-          # 'preload_has_many_association', etc.
-          send("preload_#{reflection.macro}_association", _records, reflection, preload_options)
-        end
-      end
-
-      def add_preloaded_records_to_collection(parent_records, reflection_name, associated_record)
-        parent_records.each do |parent_record|
-          association_proxy = parent_record.send(reflection_name)
-          association_proxy.loaded
-          association_proxy.target.push(*Array.wrap(associated_record))
-
-          association_proxy.__send__(:set_inverse_instance, associated_record, parent_record)
-        end
-      end
-
-      def add_preloaded_record_to_collection(parent_records, reflection_name, associated_record)
-        parent_records.each do |parent_record|
-          parent_record.send("set_#{reflection_name}_target", associated_record)
-        end
-      end
-
-      def set_association_collection_records(id_to_record_map, reflection_name, associated_records, key)
-        associated_records.each do |associated_record|
-          mapped_records = id_to_record_map[associated_record[key].to_s]
-          add_preloaded_records_to_collection(mapped_records, reflection_name, associated_record)
-        end
-      end
-
-      def set_association_single_records(id_to_record_map, reflection_name, associated_records, key)
-        seen_keys = {}
-        associated_records.each do |associated_record|
-          #this is a has_one or belongs_to: there should only be one record.
-          #Unfortunately we can't (in portable way) ask the database for
-          #'all records where foo_id in (x,y,z), but please
-          # only one row per distinct foo_id' so this where we enforce that
-          next if seen_keys[associated_record[key].to_s]
-          seen_keys[associated_record[key].to_s] = true
-          mapped_records = id_to_record_map[associated_record[key].to_s]
-          mapped_records.each do |mapped_record|
-            association_proxy = mapped_record.send("set_#{reflection_name}_target", associated_record)
-            association_proxy.__send__(:set_inverse_instance, associated_record, mapped_record)
-          end
-        end
-
-        id_to_record_map.each do |id, records|
-          next if seen_keys.include?(id.to_s)
-          records.each {|record| record.send("set_#{reflection_name}_target", nil) }
-        end
-      end
-
-      # Given a collection of Active Record objects, constructs a Hash which maps
-      # the objects' IDs to the relevant objects. Returns a 2-tuple
-      # <tt>(id_to_record_map, ids)</tt> where +id_to_record_map+ is the Hash,
-      # and +ids+ is an Array of record IDs.
-      def construct_id_map(records, primary_key=nil)
-        id_to_record_map = {}
-        ids = []
-        records.each do |record|
-          primary_key ||= record.class.primary_key
-          ids << record[primary_key]
-          mapped_records = (id_to_record_map[ids.last.to_s] ||= [])
-          mapped_records << record
-        end
-        ids.uniq!
-        return id_to_record_map, ids
-      end
-
-      def preload_has_and_belongs_to_many_association(records, reflection, preload_options={})
-        table_name = reflection.klass.quoted_table_name
-        id_to_record_map, ids = construct_id_map(records)
-        records.each {|record| record.send(reflection.name).loaded}
-        options = reflection.options
-
-        conditions = "t0.#{reflection.primary_key_name} #{in_or_equals_for_ids(ids)}"
-        conditions << append_conditions(reflection, preload_options)
-
-        associated_records_proxy = reflection.klass.unscoped.
-            includes(options[:include]).
-            joins("INNER JOIN #{connection.quote_table_name options[:join_table]} t0 ON #{reflection.klass.quoted_table_name}.#{reflection.klass.primary_key} = t0.#{reflection.association_foreign_key}").
-            select("#{options[:select] || table_name+'.*'}, t0.#{reflection.primary_key_name} as the_parent_record_id").
-            order(options[:order])
-
-        all_associated_records = associated_records(ids) do |some_ids|
-          associated_records_proxy.where([conditions, ids]).to_a
-        end
-
-        set_association_collection_records(id_to_record_map, reflection.name, all_associated_records, 'the_parent_record_id')
-      end
-
-      def preload_has_one_or_has_many_association(records, reflection, preload_options={})
-        if reflection.macro == :has_many
-          return if records.first.send(reflection.name).loaded?
-          records.each { |record| record.send(reflection.name).loaded }
-        else
-          return if records.first.send("loaded_#{reflection.name}?")
-          records.each {|record| record.send("set_#{reflection.name}_target", nil)}
-        end
-
-        options = reflection.options
-
-        if options[:through]
-          records_with_through_records = preload_through_records(records, reflection, options[:through])
-          all_through_records = records_with_through_records.map(&:last).flatten
-
-          unless all_through_records.empty?
-            source = reflection.source_reflection.name
-            all_through_records.first.class.preload_associations(all_through_records, source, options)
-
-            records_with_through_records.each do |record, through_records|
-              source_records = through_records.map(&source).flatten.compact
-
-              case reflection.macro
-                when :has_many, :has_and_belongs_to_many
-                  add_preloaded_records_to_collection([record], reflection.name, source_records)
-                when :has_one, :belongs_to
-                  add_preloaded_record_to_collection([record], reflection.name, source_records.first)
-              end
-            end
-          end
-        else
-          id_to_record_map, ids = construct_id_map(records, reflection.options[:primary_key])
-          associated_records = find_associated_records(ids, reflection, preload_options)
-
-          if reflection.macro == :has_many
-            set_association_collection_records(
-              id_to_record_map, reflection.name,
-              associated_records, reflection.primary_key_name
-            )
-          else
-            set_association_single_records(
-              id_to_record_map, reflection.name,
-              associated_records, reflection.primary_key_name
-            )
-          end
-        end
-      end
-
-      alias_method :preload_has_one_association, :preload_has_one_or_has_many_association
-      alias_method :preload_has_many_association, :preload_has_one_or_has_many_association
-
-      def preload_through_records(records, reflection, through_association)
-        # If the same through record is loaded twice, we want to return exactly the same
-        # object in the result, rather than two separate instances representing the same
-        # record. This is so that we can preload the source association for each record,
-        # and always be able to access the preloaded association regardless of where we
-        # refer to the record.
-        #
-        # Suffices to say, if AR had an identity map built in then this would be unnecessary.
-        identity_map = {}
-
-        options = {}
-
-        if reflection.options[:source_type]
-          interface = reflection.source_reflection.options[:foreign_type]
-          options[:conditions] = ["#{connection.quote_column_name interface} = ?", reflection.options[:source_type]]
-          records.compact!
-        else
-          if reflection.options[:conditions]
-            options[:include]    = reflection.options[:include] ||
-                                   reflection.options[:source]
-            options[:conditions] = reflection.options[:conditions]
-          end
-
-          options[:order] = reflection.options[:order]
-        end
-
-        records.first.class.preload_associations(records, through_association, options)
-
-        records.map do |record|
-          if reflection.options[:source_type]
-            # Dont cache the association - we would only be caching a subset
-            proxy = record.send(through_association)
-
-            if proxy.respond_to?(:target)
-              through_records = proxy.target
-              proxy.reset
-            else # this is a has_one :through reflection
-              through_records = proxy
-            end
-          else
-            through_records = record.send(through_association)
-          end
-
-          through_records = Array.wrap(through_records).map do |through_record|
-            identity_map[through_record] ||= through_record
-          end
-
-          [record, through_records]
-        end
-      end
-
-      def preload_belongs_to_association(records, reflection, preload_options={})
-        return if records.first.send("loaded_#{reflection.name}?")
-        options = reflection.options
-        primary_key_name = reflection.primary_key_name
-
-        klasses_and_ids = {}
-
-        if options[:polymorphic]
-          polymorph_type = options[:foreign_type]
-
-          # Construct a mapping from klass to a list of ids to load and a mapping of those ids back
-          # to their parent_records
-          records.each do |record|
-            if klass = record.send(polymorph_type)
-              klass_id = record.send(primary_key_name)
-              if klass_id
-                id_map = klasses_and_ids[klass] ||= {}
-                (id_map[klass_id.to_s] ||= []) << record
-              end
-            end
-          end
-        else
-          id_map = {}
-          records.each do |record|
-            key = record.send(primary_key_name)
-            (id_map[key.to_s] ||= []) << record if key
-          end
-          klasses_and_ids[reflection.klass.name] = id_map unless id_map.empty?
-        end
-
-        klasses_and_ids.each do |klass_name, _id_map|
-          klass = klass_name.constantize
-
-          table_name = klass.quoted_table_name
-          primary_key = (reflection.options[:primary_key] || klass.primary_key).to_s
-          column_type = klass.columns.detect{|c| c.name == primary_key}.type
-
-          ids = _id_map.keys.map do |id|
-            if column_type == :integer
-              id.to_i
-            elsif column_type == :float
-              id.to_f
-            else
-              id
-            end
-          end
-
-          conditions = "#{table_name}.#{connection.quote_column_name(primary_key)} #{in_or_equals_for_ids(ids)}"
-          conditions << append_conditions(reflection, preload_options)
-
-          associated_records = klass.unscoped.where([conditions, ids]).apply_finder_options(options.slice(:include, :select, :joins, :order)).to_a
-
-          set_association_single_records(_id_map, reflection.name, associated_records, primary_key)
-        end
-      end
-
-      def find_associated_records(ids, reflection, preload_options)
-        options = reflection.options
-        table_name = reflection.klass.quoted_table_name
-
-        if interface = reflection.options[:as]
-          conditions = "#{reflection.klass.quoted_table_name}.#{connection.quote_column_name "#{interface}_id"} #{in_or_equals_for_ids(ids)} and #{reflection.klass.quoted_table_name}.#{connection.quote_column_name "#{interface}_type"} = '#{self.base_class.sti_name}'"
-        else
-          foreign_key = reflection.primary_key_name
-          conditions = "#{reflection.klass.quoted_table_name}.#{foreign_key} #{in_or_equals_for_ids(ids)}"
-        end
-
-        conditions << append_conditions(reflection, preload_options)
-
-        find_options = {
-          :select => preload_options[:select] || options[:select] || Arel::SqlLiteral.new("#{table_name}.*"),
-          :include => preload_options[:include] || options[:include],
-          :joins => options[:joins],
-          :group => preload_options[:group] || options[:group],
-          :order => preload_options[:order] || options[:order]
-        }
-
-        associated_records(ids) do |some_ids|
-          reflection.klass.scoped.apply_finder_options(find_options.merge(:conditions => [conditions, some_ids])).to_a
-        end
-      end
-
-
-      def interpolate_sql_for_preload(sql)
-        instance_eval("%@#{sql.gsub('@', '\@')}@", __FILE__, __LINE__)
-      end
-
-      def append_conditions(reflection, preload_options)
-        sql = ""
-        sql << " AND (#{interpolate_sql_for_preload(reflection.sanitized_conditions)})" if reflection.sanitized_conditions
-        sql << " AND (#{sanitize_sql preload_options[:conditions]})" if preload_options[:conditions]
-        sql
-      end
-
-      def in_or_equals_for_ids(ids)
-        ids.size > 1 ? "IN (?)" : "= ?"
-      end
-
-      # Some databases impose a limit on the number of ids in a list (in Oracle its 1000)
-      # Make several smaller queries if necessary or make one query if the adapter supports it
-      def associated_records(ids)
-        in_clause_length = connection.in_clause_length || ids.size
-        records = []
-        ids.each_slice(in_clause_length) do |some_ids|
-          records += yield(some_ids)
-        end
-        records
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 9544fdcb39..ec5b41a3e7 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -5,7 +5,6 @@ require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/string/conversions'
 require 'active_support/core_ext/module/remove_method'
 require 'active_support/core_ext/class/attribute'
-require 'active_record/associations/class_methods/join_dependency'
 
 module ActiveRecord
   class InverseOfAssociationNotFoundError < ActiveRecordError #:nodoc:
@@ -20,18 +19,30 @@ module ActiveRecord
     end
   end
 
-  class HasManyThroughAssociationPolymorphicError < ActiveRecordError #:nodoc:
+  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}'.")
     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
@@ -93,8 +104,8 @@ module ActiveRecord
   # (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(reflection)
-      super("Cannot delete record because of dependent #{reflection.name}")
+    def initialize(name)
+      super("Cannot delete record because of dependent #{name}")
     end
   end
 
@@ -104,37 +115,65 @@ module ActiveRecord
 
     # These classes will be loaded when associations are created.
     # So there is no need to eager load them.
-    autoload :AssociationCollection, 'active_record/associations/association_collection'
-    autoload :AssociationProxy, 'active_record/associations/association_proxy'
-    autoload :BelongsToAssociation, 'active_record/associations/belongs_to_association'
+    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 :HasAndBelongsToManyAssociation, 'active_record/associations/has_and_belongs_to_many_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 :AliasTracker, 'active_record/associations/alias_tracker'
+    autoload :HasAndBelongsToManyAssociation,  'active_record/associations/has_and_belongs_to_many_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
+
+    autoload :Preloader,      'active_record/associations/preloader'
+    autoload :JoinDependency, 'active_record/associations/join_dependency'
+    autoload :AliasTracker,   'active_record/associations/alias_tracker'
 
     # Clears out the association cache.
     def clear_association_cache #:nodoc:
-      self.class.reflect_on_all_associations.to_a.each do |assoc|
-        instance_variable_set "@#{assoc.name}", nil
-      end if self.persisted?
+      @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?
+        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)
-        ivar = "@#{name}"
-        if instance_variable_defined?(ivar)
-          association = instance_variable_get(ivar)
-          association if association.respond_to?(:loaded?)
-        end
+        @association_cache[name.to_sym]
       end
 
       # Set the specified association instance.
       def association_instance_set(name, association)
-        instance_variable_set("@#{name}", association)
+        @association_cache[name] = association
       end
 
     # Associations are a set of macro-like class methods for tying objects together through
@@ -178,7 +217,7 @@ module ActiveRecord
     #   other=(other)                     |     X      |      X       |    X
     #   build_other(attributes={})        |     X      |              |    X
     #   create_other(attributes={})       |     X      |              |    X
-    #   other.create!(attributes={})      |            |              |    X
+    #   create_other!(attributes={})      |     X      |              |    X
     #
     # ===Collection associations (one-to-many / many-to-many)
     #                                     |       |          | has_many
@@ -201,10 +240,9 @@ module ActiveRecord
     #   others.empty?                     |   X   |    X     |    X
     #   others.clear                      |   X   |    X     |    X
     #   others.delete(other,other,...)    |   X   |    X     |    X
-    #   others.delete_all                 |   X   |    X     |
+    #   others.delete_all                 |   X   |    X     |    X
     #   others.destroy_all                |   X   |    X     |    X
     #   others.find(*args)                |   X   |    X     |    X
-    #   others.find_first                 |   X   |          |
     #   others.exists?                    |   X   |    X     |    X
     #   others.uniq                       |   X   |    X     |    X
     #   others.reset                      |   X   |    X     |    X
@@ -318,26 +356,31 @@ module ActiveRecord
     # === 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 primary
-    # 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) the assignment
-    # statement returns +false+ and the assignment is cancelled.
+    #   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>association.build</tt> method (documented below).
+    #   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.
+    #   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.
+    #   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+.
+    #   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).
+    #   <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.
+    #   saved when the parent is saved.
     #
     # === Association callbacks
     #
@@ -488,6 +531,22 @@ module ActiveRecord
     #   @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
     #
+    # 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
+    #
     # === Nested Associations
     #
     # You can actually specify *any* association with the <tt>:through</tt> option, including an
@@ -800,7 +859,7 @@ module ActiveRecord
     #      belongs_to :dungeon
     #    end
     #
-    # The +traps+ association on +Dungeon+ and the the +dungeon+ association on +Trap+ are
+    # 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
@@ -840,6 +899,73 @@ module ActiveRecord
     # * 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.
+    #
+    # === 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> will always call the <tt>destroy</tt> method of the
+    # record(s) being removed so that callbacks are run. However <tt>delete</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
@@ -864,6 +990,10 @@ module ActiveRecord
       #   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=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
@@ -919,7 +1049,7 @@ module ActiveRecord
       # * <tt>Firm#clients.create</tt> (similar to <tt>c = Client.new("firm_id" => id); c.save; c</tt>)
       # The declaration can also include an options hash to specialize the behavior of the association.
       #
-      # === Supported options
+      # === 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
@@ -947,7 +1077,9 @@ module ActiveRecord
       #   objects' foreign keys are set to +NULL+ *without* calling their +save+ callbacks. If set to
       #   <tt>:restrict</tt> this object cannot be deleted if it has any associated object.
       #
-      #   *Warning:* This option is ignored when used with <tt>:through</tt> option.
+      #   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.
       #
       # [:finder_sql]
       #   Specify a complete SQL statement to fetch the association. This is a good way to go for complex
@@ -978,14 +1110,21 @@ module ActiveRecord
       # [: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>,
+      #   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. You can use a <tt>:through</tt> association through any other,
-      #   association, but if other <tt>:through</tt> associations are involved then the resulting
-      #   association will be read-only. Otherwise, the collection of join models
-      #   can be managed via the collection API. For example, new join models are created for
-      #   newly associated objects, and if some are gone their rows are deleted (directly,
-      #   no destroy callbacks are triggered).
+      #   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.
@@ -1024,16 +1163,8 @@ module ActiveRecord
       #       'FROM people p, post_subscriptions ps ' +
       #       'WHERE ps.post_id = #{id} AND ps.person_id = p.id ' +
       #       'ORDER BY p.first_name'
-      def has_many(association_id, options = {}, &extension)
-        reflection = create_has_many_reflection(association_id, options, &extension)
-        configure_dependency_for_has_many(reflection)
-        add_association_callbacks(reflection.name, reflection.options)
-
-        if options[:through]
-          collection_accessor_methods(reflection, HasManyThroughAssociation)
-        else
-          collection_accessor_methods(reflection, HasManyAssociation)
-        end
+      def has_many(name, options = {}, &extension)
+        Builder::HasMany.build(self, name, options, &extension)
       end
 
       # Specifies a one-to-one association with another class. This method should only be used
@@ -1051,12 +1182,14 @@ module ActiveRecord
       # [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. <b>Note:</b> This ONLY works if an association already exists.
-      #   It will NOT work if the association is +nil+.
+      #   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.
       #
       # (+association+ is replaced with the symbol passed as the first argument, so
       # <tt>has_one :manager</tt> would add among others <tt>manager.nil?</tt>.)
@@ -1068,6 +1201,7 @@ module ActiveRecord
       # * <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
       #
@@ -1142,17 +1276,8 @@ module ActiveRecord
       #   has_one :boss, :readonly => :true
       #   has_one :club, :through => :membership
       #   has_one :primary_address, :through => :addressables, :conditions => ["addressable.primary = ?", true], :source => :addressable
-      def has_one(association_id, options = {})
-        if options[:through]
-          reflection = create_has_one_through_reflection(association_id, options)
-          association_accessor_methods(reflection, ActiveRecord::Associations::HasOneThroughAssociation)
-        else
-          reflection = create_has_one_reflection(association_id, options)
-          association_accessor_methods(reflection, HasOneAssociation)
-          association_constructor_method(:build,  reflection, HasOneAssociation)
-          association_constructor_method(:create, reflection, HasOneAssociation)
-          configure_dependency_for_has_one(reflection)
-        end
+      def has_one(name, options = {})
+        Builder::HasOne.build(self, name, options)
       end
 
       # Specifies a one-to-one association with another class. This method should only be used
@@ -1174,6 +1299,9 @@ module ActiveRecord
       #   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.
       #
       # (+association+ is replaced with the symbol passed as the first argument, so
       # <tt>belongs_to :author</tt> would add among others <tt>author.nil?</tt>.)
@@ -1185,6 +1313,7 @@ module ActiveRecord
       # * <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
@@ -1206,6 +1335,11 @@ module ActiveRecord
       #   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.
@@ -1261,23 +1395,8 @@ module ActiveRecord
       #   belongs_to :post, :counter_cache => true
       #   belongs_to :company, :touch => true
       #   belongs_to :company, :touch => :employees_last_updated_at
-      def belongs_to(association_id, options = {})
-        reflection = create_belongs_to_reflection(association_id, options)
-
-        if reflection.options[:polymorphic]
-          association_accessor_methods(reflection, BelongsToPolymorphicAssociation)
-          association_foreign_type_setter_method(reflection)
-        else
-          association_accessor_methods(reflection, BelongsToAssociation)
-          association_constructor_method(:build,  reflection, BelongsToAssociation)
-          association_constructor_method(:create, reflection, BelongsToAssociation)
-        end
-
-        association_foreign_key_setter_method(reflection)
-        add_counter_cache_callbacks(reflection)          if options[:counter_cache]
-        add_touch_callbacks(reflection, options[:touch]) if options[:touch]
-
-        configure_dependency_for_belongs_to(reflection)
+      def belongs_to(name, options = {})
+        Builder::BelongsTo.build(self, name, options)
       end
 
       # Specifies a many-to-many relationship with another class. This associates two classes via an
@@ -1308,12 +1427,6 @@ module ActiveRecord
       #     end
       #   end
       #
-      # Deprecated: Any additional fields added to the join table will be placed as attributes when
-      # pulling records out through +has_and_belongs_to_many+ associations. Records returned from join
-      # tables with additional attributes will be marked as readonly (because we can't save changes
-      # to the additional attributes). It's strongly recommended that you upgrade any
-      # associations with attributes to a real join model (see introduction).
-      #
       # Adds the following methods for retrieval and query:
       #
       # [collection(force_reload = false)]
@@ -1454,469 +1567,9 @@ module ActiveRecord
       #   has_and_belongs_to_many :categories, :readonly => true
       #   has_and_belongs_to_many :active_projects, :join_table => 'developers_projects', :delete_sql =>
       #   'DELETE FROM developers_projects WHERE active=1 AND developer_id = #{id} AND project_id = #{record.id}'
-      def has_and_belongs_to_many(association_id, options = {}, &extension)
-        reflection = create_has_and_belongs_to_many_reflection(association_id, options, &extension)
-        collection_accessor_methods(reflection, HasAndBelongsToManyAssociation)
-
-        # Don't use a before_destroy callback since users' before_destroy
-        # callbacks will be executed after the association is wiped out.
-        include Module.new {
-          class_eval <<-RUBY, __FILE__, __LINE__ + 1
-            def destroy                     # def destroy
-              #{reflection.name}.clear      #   posts.clear
-              super                         #   super
-            end                             # end
-          RUBY
-        }
-
-        add_association_callbacks(reflection.name, options)
+      def has_and_belongs_to_many(name, options = {}, &extension)
+        Builder::HasAndBelongsToMany.build(self, name, options, &extension)
       end
-
-      private
-        # Generates a join table name from two provided table names.
-        # The names in the join table names end up in lexicographic order.
-        #
-        #   join_table_name("members", "clubs")         # => "clubs_members"
-        #   join_table_name("members", "special_clubs") # => "members_special_clubs"
-        def join_table_name(first_table_name, second_table_name)
-          if first_table_name < second_table_name
-            join_table = "#{first_table_name}_#{second_table_name}"
-          else
-            join_table = "#{second_table_name}_#{first_table_name}"
-          end
-
-          table_name_prefix + join_table + table_name_suffix
-        end
-
-        def association_accessor_methods(reflection, association_proxy_class)
-          redefine_method(reflection.name) do |*params|
-            force_reload = params.first unless params.empty?
-            association = association_instance_get(reflection.name)
-
-            if association.nil? || force_reload
-              association = association_proxy_class.new(self, reflection)
-              retval = force_reload ? reflection.klass.uncached { association.reload } : association.reload
-              if retval.nil? and association_proxy_class == BelongsToAssociation
-                association_instance_set(reflection.name, nil)
-                return nil
-              end
-              association_instance_set(reflection.name, association)
-            end
-
-            association.target.nil? ? nil : association
-          end
-
-          redefine_method("loaded_#{reflection.name}?") do
-            association = association_instance_get(reflection.name)
-            association && association.loaded?
-          end
-
-          redefine_method("#{reflection.name}=") do |new_value|
-            association = association_instance_get(reflection.name)
-
-            if association.nil? || association.target != new_value
-              association = association_proxy_class.new(self, reflection)
-            end
-
-            association.replace(new_value)
-            association_instance_set(reflection.name, new_value.nil? ? nil : association)
-          end
-
-          redefine_method("set_#{reflection.name}_target") do |target|
-            return if target.nil? and association_proxy_class == BelongsToAssociation
-            association = association_proxy_class.new(self, reflection)
-            association.target = target
-            association_instance_set(reflection.name, association)
-          end
-        end
-
-        def collection_reader_method(reflection, association_proxy_class)
-          redefine_method(reflection.name) do |*params|
-            force_reload = params.first unless params.empty?
-            association = association_instance_get(reflection.name)
-
-            unless association
-              association = association_proxy_class.new(self, reflection)
-              association_instance_set(reflection.name, association)
-            end
-
-            reflection.klass.uncached { association.reload } if force_reload
-
-            association
-          end
-
-          redefine_method("#{reflection.name.to_s.singularize}_ids") do
-            if send(reflection.name).loaded? || reflection.options[:finder_sql]
-              send(reflection.name).map { |r| r.id }
-            else
-              if reflection.through_reflection && reflection.source_reflection.belongs_to?
-                through = reflection.through_reflection
-                primary_key = reflection.source_reflection.primary_key_name
-                send(through.name).select("DISTINCT #{through.quoted_table_name}.#{primary_key}").map! { |r| r.send(primary_key) }
-              else
-                send(reflection.name).select("#{reflection.quoted_table_name}.#{reflection.klass.primary_key}").except(:includes).map! { |r| r.id }
-              end
-            end
-          end
-
-        end
-
-        def collection_accessor_methods(reflection, association_proxy_class, writer = true)
-          collection_reader_method(reflection, association_proxy_class)
-
-          if writer
-            redefine_method("#{reflection.name}=") do |new_value|
-              # Loads proxy class instance (defined in collection_reader_method) if not already loaded
-              association = send(reflection.name)
-              association.replace(new_value)
-              association
-            end
-
-            redefine_method("#{reflection.name.to_s.singularize}_ids=") do |new_value|
-              pk_column = reflection.primary_key_column
-              ids = (new_value || []).reject { |nid| nid.blank? }
-              ids.map!{ |i| pk_column.type_cast(i) }
-              send("#{reflection.name}=", reflection.klass.find(ids).index_by{ |r| r.id }.values_at(*ids))
-            end
-          end
-        end
-
-        def association_constructor_method(constructor, reflection, association_proxy_class)
-          redefine_method("#{constructor}_#{reflection.name}") do |*params|
-            attributees      = params.first unless params.empty?
-            replace_existing = params[1].nil? ? true : params[1]
-            association      = association_instance_get(reflection.name)
-
-            unless association
-              association = association_proxy_class.new(self, reflection)
-              association_instance_set(reflection.name, association)
-            end
-
-            if association_proxy_class == HasOneAssociation
-              association.send(constructor, attributees, replace_existing)
-            else
-              association.send(constructor, attributees)
-            end
-          end
-        end
-
-        def association_foreign_key_setter_method(reflection)
-          setters = reflect_on_all_associations(:belongs_to).map do |belongs_to_reflection|
-            if belongs_to_reflection.primary_key_name == reflection.primary_key_name
-              "association_instance_set(:#{belongs_to_reflection.name}, nil);"
-            end
-          end.compact.join
-
-          if method_defined?(:"#{reflection.primary_key_name}=")
-            undef_method :"#{reflection.primary_key_name}="
-          end
-
-          class_eval <<-FILE, __FILE__, __LINE__ + 1
-            def #{reflection.primary_key_name}=(new_id)
-              write_attribute :#{reflection.primary_key_name}, new_id
-              if #{reflection.primary_key_name}_changed?
-                #{ setters }
-              end
-            end
-          FILE
-        end
-
-        def association_foreign_type_setter_method(reflection)
-          setters = reflect_on_all_associations(:belongs_to).map do |belongs_to_reflection|
-            if belongs_to_reflection.options[:foreign_type] == reflection.options[:foreign_type]
-              "association_instance_set(:#{belongs_to_reflection.name}, nil);"
-            end
-          end.compact.join
-
-          field = reflection.options[:foreign_type]
-          class_eval <<-FILE, __FILE__, __LINE__ + 1
-            def #{field}=(new_id)
-              write_attribute :#{field}, new_id
-              if #{field}_changed?
-                #{ setters }
-              end
-            end
-          FILE
-        end
-
-        def add_counter_cache_callbacks(reflection)
-          cache_column = reflection.counter_cache_column
-
-          method_name = "belongs_to_counter_cache_after_create_for_#{reflection.name}".to_sym
-          define_method(method_name) do
-            association = send(reflection.name)
-            association.class.increment_counter(cache_column, association.id) unless association.nil?
-          end
-          after_create(method_name)
-
-          method_name = "belongs_to_counter_cache_before_destroy_for_#{reflection.name}".to_sym
-          define_method(method_name) do
-            association = send(reflection.name)
-            association.class.decrement_counter(cache_column, association.id) unless association.nil?
-          end
-          before_destroy(method_name)
-
-          module_eval(
-            "#{reflection.class_name}.send(:attr_readonly,\"#{cache_column}\".intern) if defined?(#{reflection.class_name}) && #{reflection.class_name}.respond_to?(:attr_readonly)", __FILE__, __LINE__
-          )
-        end
-
-        def add_touch_callbacks(reflection, touch_attribute)
-          method_name = :"belongs_to_touch_after_save_or_destroy_for_#{reflection.name}"
-          redefine_method(method_name) do
-            association = send(reflection.name)
-
-            if touch_attribute == true
-              association.touch unless association.nil?
-            else
-              association.touch(touch_attribute) unless association.nil?
-            end
-          end
-          after_save(method_name)
-          after_touch(method_name)
-          after_destroy(method_name)
-        end
-
-        # Creates before_destroy callback methods that nullify, delete or destroy
-        # has_many associated objects, according to the defined :dependent rule.
-        #
-        # See HasManyAssociation#delete_records for more information. In general
-        #  - delete children if the option is set to :destroy or :delete_all
-        #  - set the foreign key to NULL if the option is set to :nullify
-        #  - do not delete the parent record if there is any child record if the
-        #    option is set to :restrict
-        #
-        # The +extra_conditions+ parameter, which is not used within the main
-        # Active Record codebase, is meant to allow plugins to define extra
-        # finder conditions.
-        def configure_dependency_for_has_many(reflection, extra_conditions = nil)
-          if reflection.options.include?(:dependent)
-            case reflection.options[:dependent]
-              when :destroy
-                method_name = "has_many_dependent_destroy_for_#{reflection.name}".to_sym
-                define_method(method_name) do
-                  send(reflection.name).each do |o|
-                    # No point in executing the counter update since we're going to destroy the parent anyway
-                    counter_method = ('belongs_to_counter_cache_before_destroy_for_' + self.class.name.downcase).to_sym
-                    if(o.respond_to? counter_method) then
-                      class << o
-                        self
-                      end.send(:define_method, counter_method, Proc.new {})
-                    end
-                    o.destroy
-                  end
-                end
-                before_destroy method_name
-              when :delete_all
-                before_destroy do |record|
-                  self.class.send(:delete_all_has_many_dependencies,
-                  record,
-                  reflection.name,
-                  reflection.klass,
-                  reflection.dependent_conditions(record, self.class, extra_conditions))
-                end
-              when :nullify
-                before_destroy do |record|
-                  self.class.send(:nullify_has_many_dependencies,
-                  record,
-                  reflection.name,
-                  reflection.klass,
-                  reflection.primary_key_name,
-                  reflection.dependent_conditions(record, self.class, extra_conditions))
-                end
-              when :restrict
-                method_name = "has_many_dependent_restrict_for_#{reflection.name}".to_sym
-                define_method(method_name) do
-                  unless send(reflection.name).empty?
-                    raise DeleteRestrictionError.new(reflection)
-                  end
-                end
-                before_destroy method_name
-              else
-                raise ArgumentError, "The :dependent option expects either :destroy, :delete_all, :nullify or :restrict (#{reflection.options[:dependent].inspect})"
-            end
-          end
-        end
-
-        # Creates before_destroy callback methods that nullify, delete or destroy
-        # has_one associated objects, according to the defined :dependent rule.
-        # If the association is marked as :dependent => :restrict, create a callback
-        # that prevents deleting entirely.
-        def configure_dependency_for_has_one(reflection)
-          if reflection.options.include?(:dependent)
-            name = reflection.options[:dependent]
-            method_name = :"has_one_dependent_#{name}_for_#{reflection.name}"
-
-            case name
-              when :destroy, :delete
-                class_eval <<-eoruby, __FILE__, __LINE__ + 1
-                  def #{method_name}
-                    association = #{reflection.name}
-                    association.#{name} if association
-                  end
-                eoruby
-              when :nullify
-                class_eval <<-eoruby, __FILE__, __LINE__ + 1
-                  def #{method_name}
-                    association = #{reflection.name}
-                    association.update_attribute(#{reflection.primary_key_name.inspect}, nil) if association
-                  end
-                eoruby
-              when :restrict
-                method_name = "has_one_dependent_restrict_for_#{reflection.name}".to_sym
-                define_method(method_name) do
-                  unless send(reflection.name).nil?
-                    raise DeleteRestrictionError.new(reflection)
-                  end
-                end
-                before_destroy method_name
-              else
-                raise ArgumentError, "The :dependent option expects either :destroy, :delete, :nullify or :restrict (#{reflection.options[:dependent].inspect})"
-            end
-
-            before_destroy method_name
-          end
-        end
-
-        def configure_dependency_for_belongs_to(reflection)
-          if reflection.options.include?(:dependent)
-            name = reflection.options[:dependent]
-
-            unless [:destroy, :delete].include?(name)
-              raise ArgumentError, "The :dependent option expects either :destroy or :delete (#{reflection.options[:dependent].inspect})"
-            end
-
-            method_name = :"belongs_to_dependent_#{name}_for_#{reflection.name}"
-            class_eval <<-eoruby, __FILE__, __LINE__ + 1
-              def #{method_name}
-                association = #{reflection.name}
-                association.#{name} if association
-              end
-            eoruby
-            after_destroy method_name
-          end
-        end
-
-        def delete_all_has_many_dependencies(record, reflection_name, association_class, dependent_conditions)
-          association_class.delete_all(dependent_conditions)
-        end
-
-        def nullify_has_many_dependencies(record, reflection_name, association_class, primary_key_name, dependent_conditions)
-          association_class.update_all("#{primary_key_name} = NULL", dependent_conditions)
-        end
-
-        mattr_accessor :valid_keys_for_has_many_association
-        @@valid_keys_for_has_many_association = [
-          :class_name, :table_name, :foreign_key, :primary_key,
-          :dependent,
-          :select, :conditions, :include, :order, :group, :having, :limit, :offset,
-          :as, :through, :source, :source_type,
-          :uniq,
-          :finder_sql, :counter_sql,
-          :before_add, :after_add, :before_remove, :after_remove,
-          :extend, :readonly,
-          :validate, :inverse_of
-        ]
-
-        def create_has_many_reflection(association_id, options, &extension)
-          options.assert_valid_keys(valid_keys_for_has_many_association)
-          options[:extend] = create_extension_modules(association_id, extension, options[:extend])
-
-          create_reflection(:has_many, association_id, options, self)
-        end
-
-        mattr_accessor :valid_keys_for_has_one_association
-        @@valid_keys_for_has_one_association = [
-          :class_name, :foreign_key, :remote, :select, :conditions, :order,
-          :include, :dependent, :counter_cache, :extend, :as, :readonly,
-          :validate, :primary_key, :inverse_of
-        ]
-
-        def create_has_one_reflection(association_id, options)
-          options.assert_valid_keys(valid_keys_for_has_one_association)
-          create_reflection(:has_one, association_id, options, self)
-        end
-
-        def create_has_one_through_reflection(association_id, options)
-          options.assert_valid_keys(
-            :class_name, :foreign_key, :remote, :select, :conditions, :order, :include, :dependent, :counter_cache, :extend, :as, :through, :source, :source_type, :validate
-          )
-          create_reflection(:has_one, association_id, options, self)
-        end
-
-        mattr_accessor :valid_keys_for_belongs_to_association
-        @@valid_keys_for_belongs_to_association = [
-          :class_name, :primary_key, :foreign_key, :foreign_type, :remote, :select, :conditions,
-          :include, :dependent, :counter_cache, :extend, :polymorphic, :readonly,
-          :validate, :touch, :inverse_of
-        ]
-
-        def create_belongs_to_reflection(association_id, options)
-          options.assert_valid_keys(valid_keys_for_belongs_to_association)
-          reflection = create_reflection(:belongs_to, association_id, options, self)
-
-          if options[:polymorphic]
-            reflection.options[:foreign_type] ||= reflection.class_name.underscore + "_type"
-          end
-
-          reflection
-        end
-
-        mattr_accessor :valid_keys_for_has_and_belongs_to_many_association
-        @@valid_keys_for_has_and_belongs_to_many_association = [
-          :class_name, :table_name, :join_table, :foreign_key, :association_foreign_key,
-          :select, :conditions, :include, :order, :group, :having, :limit, :offset,
-          :uniq,
-          :finder_sql, :counter_sql, :delete_sql, :insert_sql,
-          :before_add, :after_add, :before_remove, :after_remove,
-          :extend, :readonly,
-          :validate
-        ]
-
-        def create_has_and_belongs_to_many_reflection(association_id, options, &extension)
-          options.assert_valid_keys(valid_keys_for_has_and_belongs_to_many_association)
-          options[:extend] = create_extension_modules(association_id, extension, options[:extend])
-
-          reflection = create_reflection(:has_and_belongs_to_many, association_id, options, self)
-
-          if reflection.association_foreign_key == reflection.primary_key_name
-            raise HasAndBelongsToManyAssociationForeignKeyNeeded.new(reflection)
-          end
-
-          reflection.options[:join_table] ||= join_table_name(undecorated_table_name(self.to_s), undecorated_table_name(reflection.class_name))
-          if connection.supports_primary_key? && (connection.primary_key(reflection.options[:join_table]) rescue false)
-             raise HasAndBelongsToManyAssociationWithPrimaryKeyError.new(reflection)
-          end
-
-          reflection
-        end
-
-        def add_association_callbacks(association_name, options)
-          callbacks = %w(before_add after_add before_remove after_remove)
-          callbacks.each do |callback_name|
-            full_callback_name = "#{callback_name}_for_#{association_name}"
-            defined_callbacks = options[callback_name.to_sym]
-
-            full_callback_value = options.has_key?(callback_name.to_sym) ? [defined_callbacks].flatten : []
-
-            # TODO : why do i need method_defined? I think its because of the inheritance chain
-            class_attribute full_callback_name.to_sym unless method_defined?(full_callback_name)
-            self.send("#{full_callback_name}=", full_callback_value)
-          end
-        end
-
-        def create_extension_modules(association_id, block_extension, extensions)
-          if block_extension
-            extension_module_name = "#{self.to_s.demodulize}#{association_id.to_s.camelize}AssociationExtension"
-
-            silence_warnings do
-              self.parent.const_set(extension_module_name, Module.new(&block_extension))
-            end
-            Array.wrap(extensions).push("#{self.parent}::#{extension_module_name}".constantize)
-          else
-            Array.wrap(extensions)
-          end
-        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/associations/alias_tracker.rb b/activerecord/lib/active_record/associations/alias_tracker.rb
index 6428fcec0a..6fc2bfdb31 100644
--- a/activerecord/lib/active_record/associations/alias_tracker.rb
+++ b/activerecord/lib/active_record/associations/alias_tracker.rb
@@ -5,32 +5,44 @@ module ActiveRecord
     # Keeps track of table aliases for ActiveRecord::Associations::ClassMethods::JoinDependency and
     # ActiveRecord::Associations::ThroughAssociationScope
     class AliasTracker # :nodoc:
+      attr_reader :aliases, :table_joins
+
       # table_joins is an array of arel joins which might conflict with the aliases we assign here
-      def initialize(table_joins = nil)
+      def initialize(table_joins = [])
         @aliases     = Hash.new
         @table_joins = table_joins
       end
 
+      def aliased_table_for(table_name, aliased_name = nil)
+        table_alias = aliased_name_for(table_name, aliased_name)
+
+        if table_alias == table_name # TODO: Is this conditional necessary?
+          Arel::Table.new(table_name)
+        else
+          Arel::Table.new(table_name).alias(table_alias)
+        end
+      end
+
       def aliased_name_for(table_name, aliased_name = nil)
         aliased_name ||= table_name
 
-        initialize_count_for(table_name) if @aliases[table_name].nil?
+        initialize_count_for(table_name) if aliases[table_name].nil?
 
-        if @aliases[table_name].zero?
+        if aliases[table_name].zero?
           # If it's zero, we can have our table_name
-          @aliases[table_name] = 1
+          aliases[table_name] = 1
           table_name
         else
           # Otherwise, we need to use an alias
           aliased_name = connection.table_alias_for(aliased_name)
 
-          initialize_count_for(aliased_name) if @aliases[aliased_name].nil?
+          initialize_count_for(aliased_name) if aliases[aliased_name].nil?
 
           # Update the count
-          @aliases[aliased_name] += 1
+          aliases[aliased_name] += 1
 
-          if @aliases[aliased_name] > 1
-            "#{truncate(aliased_name)}_#{@aliases[aliased_name]}"
+          if aliases[aliased_name] > 1
+            "#{truncate(aliased_name)}_#{aliases[aliased_name]}"
           else
             aliased_name
           end
@@ -44,29 +56,21 @@ module ActiveRecord
       private
 
         def initialize_count_for(name)
-          @aliases[name] = 0
+          aliases[name] = 0
 
-          unless @table_joins.nil? || Arel::Table === @table_joins
+          unless Arel::Table === 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
 
-            @aliases[name] += @table_joins.grep(Arel::Nodes::Join).map { |join|
-              right = join.right
-              case right
-              when Arel::Table
-                right.name.downcase == name ? 1 : 0
-              when String
-                # Table names + table aliases
-                right.downcase.scan(
-                  /join(?:\s+\w+)?\s+(\S+\s+)?#{quoted_name}\son/
-                ).size
-              else
-                0
-              end
+            aliases[name] += table_joins.map { |join|
+              # Table names + table aliases
+              join.left.downcase.scan(
+                /join(?:\s+\w+)?\s+(\S+\s+)?#{quoted_name}\son/
+              ).size
             }.sum
           end
 
-          @aliases[name]
+          aliases[name]
         end
 
         def truncate(name)
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
new file mode 100644
index 0000000000..86904ea2bc
--- /dev/null
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -0,0 +1,262 @@
+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
+    #     SingularAssociaton
+    #       HasOneAssociation
+    #         HasOneThroughAssociation + ThroughAssociation
+    #       BelongsToAssociation
+    #         BelongsToPolymorphicAssociation
+    #     CollectionAssociation
+    #       HasAndBelongsToManyAssociation
+    #       HasManyAssociation
+    #         HasManyThroughAssociation + ThroughAssociation
+    class Association #:nodoc:
+      attr_reader :owner, :target, :reflection
+
+      delegate :options, :to => :reflection
+
+      def initialize(owner, reflection)
+        reflection.check_validity!
+
+        @target = nil
+        @owner, @reflection = owner, reflection
+        @updated = false
+
+        reset
+        construct_scope
+      end
+
+      # Returns the name of the table of the related class:
+      #
+      #   post.comments.aliased_table_name # => "comments"
+      #
+      def aliased_table_name
+        reflection.klass.table_name
+      end
+
+      # Resets the \loaded flag to +false+ and sets the \target to +nil+.
+      def reset
+        @loaded = false
+        IdentityMap.remove(target) if IdentityMap.enabled? && target
+        @target = nil
+      end
+
+      # Reloads the \target and returns +self+ on success.
+      def reload
+        reset
+        construct_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
+      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
+      # state_state method if relevant.
+      #
+      # Note that if the target has not been loaded, it is not considered stale.
+      def stale_target?
+        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 scoped
+        target_scope.merge(@association_scope)
+      end
+
+      # Construct the scope for this association.
+      #
+      # Note that the association_scope is merged into the targed_scope only when the
+      # scoped 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 construct_scope
+        @association_scope = association_scope if klass
+      end
+
+      def association_scope
+        scope = klass.unscoped
+        scope = scope.create_with(creation_attributes)
+        scope = scope.apply_finder_options(options.slice(:readonly, :include))
+        scope = scope.where(interpolate(options[:conditions]))
+        if select = select_value
+          scope = scope.select(select)
+        end
+        scope = scope.extending(*Array.wrap(options[:extend]))
+        scope.where(construct_owner_conditions)
+      end
+
+      def aliased_table
+        klass.arel_table
+      end
+
+      # Set the inverse association, if possible
+      def set_inverse_instance(record)
+        if record && invertible_for?(record)
+          inverse = record.association(inverse_reflection_for(record).name)
+          inverse.target = owner
+        end
+      end
+
+      # This 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
+        klass.scoped
+      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
+        if find_target?
+          begin
+            if IdentityMap.enabled? && association_class && association_class.respond_to?(:base_class)
+              @target = IdentityMap.get(association_class, owner[reflection.foreign_key])
+            end
+          rescue NameError
+            nil
+          ensure
+            @target ||= find_target
+          end
+        end
+        loaded!
+        target
+      rescue ActiveRecord::RecordNotFound
+        reset
+      end
+
+      private
+
+        def find_target?
+          !loaded? && (!owner.new_record? || foreign_key_present?) && klass
+        end
+
+        def interpolate(sql, record = nil)
+          if sql.respond_to?(:to_proc)
+            owner.send(:instance_exec, record, &sql)
+          else
+            sql
+          end
+        end
+
+        def select_value
+          options[:select]
+        end
+
+        # Implemented by (some) subclasses
+        def creation_attributes
+          { }
+        end
+
+        # Returns a hash linking the owner to the association represented by the reflection
+        def construct_owner_attributes(reflection = reflection)
+          attributes = {}
+          if reflection.macro == :belongs_to
+            attributes[reflection.association_primary_key] = owner[reflection.foreign_key]
+          else
+            attributes[reflection.foreign_key] = owner[reflection.active_record_primary_key]
+
+            if options[:as]
+              attributes["#{options[:as]}_type"] = owner.class.base_class.name
+            end
+          end
+          attributes
+        end
+
+        # Builds an array of arel nodes from the owner attributes hash
+        def construct_owner_conditions(table = aliased_table, reflection = reflection)
+          conditions = construct_owner_attributes(reflection).map do |attr, value|
+            table[attr].eq(value)
+          end
+          table.create_and(conditions)
+        end
+
+        # Sets the owner attributes on the given record
+        def set_owner_attributes(record)
+          if owner.persisted?
+            construct_owner_attributes.each { |key, value| record[key] = value }
+          end
+        end
+
+        # Should be 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).
+        #
+        # 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
+
+        # Is this association invertible? Can be redefined by subclasses.
+        def invertible_for?(record)
+          inverse_reflection_for(record)
+        end
+
+        # This should be implemented to return the values of the relevant key(s) on the owner,
+        # so that when state_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 association_class
+          @reflection.klass
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
deleted file mode 100644
index abb17a11c6..0000000000
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ /dev/null
@@ -1,558 +0,0 @@
-require 'set'
-require 'active_support/core_ext/array/wrap'
-
-module ActiveRecord
-  module Associations
-    # = Active Record Association Collection
-    #
-    # AssociationCollection is an abstract class that provides common stuff to
-    # ease the implementation of association proxies that represent
-    # collections. See the class hierarchy in AssociationProxy.
-    #
-    # 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 AssociationCollection < AssociationProxy #:nodoc:
-      delegate :group, :order, :limit, :joins, :where, :preload, :eager_load, :includes, :from, :lock, :readonly, :having, :to => :scoped
-
-      def select(select = nil)
-        if block_given?
-          load_target
-          @target.select.each { |e| yield e }
-        else
-          scoped.select(select)
-        end
-      end
-
-      def scoped
-        with_scope(@scope) { @reflection.klass.scoped }
-      end
-
-      def find(*args)
-        options = args.extract_options!
-
-        # If using a custom finder_sql, scan the entire collection.
-        if @reflection.options[:finder_sql]
-          expects_array = args.first.kind_of?(Array)
-          ids           = args.flatten.compact.uniq.map { |arg| arg.to_i }
-
-          if ids.size == 1
-            id = ids.first
-            record = load_target.detect { |r| id == r.id }
-            expects_array ? [ record ] : record
-          else
-            load_target.select { |r| ids.include?(r.id) }
-          end
-        else
-          merge_options_from_reflection!(options)
-          construct_find_options!(options)
-
-          with_scope(:find => @scope[:find].slice(:conditions, :order)) do
-            relation = @reflection.klass.send(:construct_finder_arel, options, @reflection.klass.send(:current_scoped_methods))
-
-            case args.first
-            when :first, :last
-              relation.send(args.first)
-            when :all
-              records = relation.all
-              @reflection.options[:uniq] ? uniq(records) : records
-            else
-              relation.find(*args)
-            end
-          end
-        end
-      end
-
-      # Fetches the first one using SQL if possible.
-      def first(*args)
-        if fetch_first_or_last_using_find?(args)
-          find(:first, *args)
-        else
-          load_target unless loaded?
-          args = args[1..-1] if args.first.kind_of?(Hash) && args.first.empty?
-          @target.first(*args)
-        end
-      end
-
-      # Fetches the last one using SQL if possible.
-      def last(*args)
-        if fetch_first_or_last_using_find?(args)
-          find(:last, *args)
-        else
-          load_target unless loaded?
-          @target.last(*args)
-        end
-      end
-
-      def to_ary
-        load_target
-        if @target.is_a?(Array)
-          @target.to_ary
-        else
-          Array.wrap(@target)
-        end
-      end
-      alias_method :to_a, :to_ary
-
-      def reset
-        reset_target!
-        reset_named_scopes_cache!
-        @loaded = false
-      end
-
-      def build(attributes = {}, &block)
-        if attributes.is_a?(Array)
-          attributes.collect { |attr| build(attr, &block) }
-        else
-          build_record(attributes) do |record|
-            block.call(record) if block_given?
-            set_belongs_to_association_for(record)
-          end
-        end
-      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 <<(*records)
-        result = true
-        load_target if @owner.new_record?
-
-        transaction do
-          flatten_deeper(records).each do |record|
-            raise_on_type_mismatch(record)
-            add_record_to_target_with_callbacks(record) do |r|
-              result &&= insert_record(record) unless @owner.new_record?
-            end
-          end
-        end
-
-        result && self
-      end
-
-      alias_method :push, :<<
-      alias_method :concat, :<<
-
-      # 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
-
-      # Remove all records from this association
-      #
-      # See delete for more info.
-      def delete_all
-        load_target
-        delete(@target)
-        reset_target!
-        reset_named_scopes_cache!
-      end
-
-      # Calculate sum using SQL, not Enumerable
-      def sum(*args)
-        if block_given?
-          calculate(:sum, *args) { |*block_args| yield(*block_args) }
-        else
-          calculate(:sum, *args)
-        end
-      end
-
-      # Count all records using SQL. If the +:counter_sql+ or +:finder_sql+ option is set for the
-      # association, it will be used for the query. Otherwise, construct options and pass them with
-      # scope to the target class's +count+.
-      def count(column_name = nil, options = {})
-        column_name, options = nil, column_name if column_name.is_a?(Hash)
-
-        if @reflection.options[:counter_sql] || @reflection.options[:finder_sql]
-          unless options.blank?
-            raise ArgumentError, "If finder_sql/counter_sql is used then options cannot be passed"
-          end
-
-          @reflection.klass.count_by_sql(custom_counter_sql)
-        else
-
-          if @reflection.options[:uniq]
-            # This is needed because 'SELECT count(DISTINCT *)..' is not valid SQL.
-            column_name = "#{@reflection.quoted_table_name}.#{@reflection.klass.primary_key}" unless column_name
-            options.merge!(:distinct => true)
-          end
-
-          value = @reflection.klass.send(:with_scope, @scope) { @reflection.klass.count(column_name, options) }
-
-          limit  = @reflection.options[:limit]
-          offset = @reflection.options[:offset]
-
-          if limit || offset
-            [ [value - offset.to_i, 0].max, limit.to_i ].min
-          else
-            value
-          end
-        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)
-        remove_records(records) do |_records, old_records|
-          delete_records(old_records) if old_records.any?
-          _records.each { |record| @target.delete(record) }
-        end
-      end
-
-      # Destroy +records+ and remove them from this association calling
-      # +before_remove+ and +after_remove+ callbacks.
-      #
-      # Note that this method will _always_ remove records from the database
-      # ignoring the +:dependent+ option.
-      def destroy(*records)
-        records = find(records) if records.any? {|record| record.kind_of?(Fixnum) || record.kind_of?(String)}
-        remove_records(records) do |_records, old_records|
-          old_records.each { |record| record.destroy }
-        end
-
-        load_target
-      end
-
-      # Removes all records from this association.  Returns +self+ so method calls may be chained.
-      def clear
-        unless length.zero? # forces load_target if it hasn't happened already
-          if @reflection.options[:dependent] == :destroy
-            destroy_all
-          else
-            delete_all
-          end
-        end
-
-        self
-      end
-
-      # Destroy all the records from this association.
-      #
-      # See destroy for more info.
-      def destroy_all
-        load_target
-        destroy(@target).tap do
-          reset_target!
-          reset_named_scopes_cache!
-        end
-      end
-
-      def create(attrs = {})
-        if attrs.is_a?(Array)
-          attrs.collect { |attr| create(attr) }
-        else
-          create_record(attrs) do |record|
-            yield(record) if block_given?
-            record.save
-          end
-        end
-      end
-
-      def create!(attrs = {})
-        create_record(attrs) do |record|
-          yield(record) if block_given?
-          record.save!
-        end
-      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 @owner.new_record? || (loaded? && !@reflection.options[:uniq])
-          @target.size
-        elsif !loaded? && @reflection.options[:group]
-          load_target.size
-        elsif !loaded? && !@reflection.options[:uniq] && @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
-
-      # Equivalent to <tt>collection.size.zero?</tt>. If the collection has
-      # not been already loaded and you are going to fetch the records anyway
-      # it is better to check <tt>collection.length.zero?</tt>.
-      def empty?
-        size.zero?
-      end
-
-      def any?
-        if block_given?
-          method_missing(: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?
-          method_missing(:many?) { |*block_args| yield(*block_args) }
-        else
-          size > 1
-        end
-      end
-
-      def uniq(collection = self)
-        seen = {}
-        collection.find_all do |record|
-          seen[record.id] = true unless seen.key?(record.id)
-        end
-      end
-
-      # 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) }
-
-        load_target
-        other   = other_array.size < 100 ? other_array : other_array.to_set
-        current = @target.size < 100 ? @target : @target.to_set
-
-        transaction do
-          delete(@target.select { |v| !other.include?(v) })
-          concat(other_array.select { |v| !current.include?(v) })
-        end
-      end
-
-      def include?(record)
-        return false unless record.is_a?(@reflection.klass)
-        return include_in_memory?(record) if record.new_record?
-        load_target if @reflection.options[:finder_sql] && !loaded?
-        loaded? ? @target.include?(record) : exists?(record)
-      end
-
-      def proxy_respond_to?(method, include_private = false)
-        super || @reflection.klass.respond_to?(method, include_private)
-      end
-
-      protected
-        def construct_find_options!(options)
-        end
-
-        def load_target
-          if !@owner.new_record? || foreign_key_present
-            begin
-              unless loaded?
-                if @target.is_a?(Array) && @target.any?
-                  @target = find_target.map do |f|
-                    i = @target.index(f)
-                    if i
-                      @target.delete_at(i).tap do |t|
-                        keys = ["id"] + t.changes.keys + (f.attribute_names - t.attribute_names)
-                        f.attributes.except(*keys).each do |k,v|
-                          t.send("#{k}=", v)
-                        end
-                      end
-                    else
-                      f
-                    end
-                  end + @target
-                else
-                  @target = find_target
-                end
-              end
-            rescue ActiveRecord::RecordNotFound
-              reset
-            end
-          end
-
-          loaded if target
-          target
-        end
-
-        def method_missing(method, *args)
-          match = DynamicFinderMatch.match(method)
-          if match && match.creator?
-            attributes = match.attribute_names
-            return send(:"find_by_#{attributes.join('_and_')}", *args) || create(Hash[attributes.zip(args)])
-          end
-
-          if @target.respond_to?(method) || (!@reflection.klass.respond_to?(method) && Class.respond_to?(method))
-            super
-          elsif @reflection.klass.scopes[method]
-            @_named_scopes_cache ||= {}
-            @_named_scopes_cache[method] ||= {}
-            @_named_scopes_cache[method][args] ||= with_scope(@scope) { @reflection.klass.send(method, *args) }
-          else
-            with_scope(@scope) do
-              if block_given?
-                @reflection.klass.send(method, *args) { |*block_args| yield(*block_args) }
-              else
-                @reflection.klass.send(method, *args)
-              end
-            end
-          end
-        end
-
-        def custom_counter_sql
-          if @reflection.options[:counter_sql]
-            counter_sql = @reflection.options[:counter_sql]
-          else
-            # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */
-            counter_sql = @reflection.options[:finder_sql].sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" }
-          end
-
-          interpolate_sql(counter_sql)
-        end
-
-        def custom_finder_sql
-          interpolate_sql(@reflection.options[:finder_sql])
-        end
-
-        def reset_target!
-          @target = Array.new
-        end
-
-        def reset_named_scopes_cache!
-          @_named_scopes_cache = {}
-        end
-
-        def find_target
-          records =
-            if @reflection.options[:finder_sql]
-              @reflection.klass.find_by_sql(custom_finder_sql)
-            else
-              find(:all)
-            end
-
-          records = @reflection.options[:uniq] ? uniq(records) : records
-          records.each do |record|
-            set_inverse_instance(record, @owner)
-          end
-          records
-        end
-
-        def add_record_to_target_with_callbacks(record)
-          callback(:before_add, record)
-          yield(record) if block_given?
-          @target ||= [] unless loaded?
-          if index = @target.index(record)
-            @target[index] = record
-          else
-             @target << record
-          end
-          callback(:after_add, record)
-          set_inverse_instance(record, @owner)
-          record
-        end
-
-      private
-        def create_record(attrs)
-          attrs.update(@reflection.options[:conditions]) if @reflection.options[:conditions].is_a?(Hash)
-          ensure_owner_is_persisted!
-
-          scoped_where = scoped.where_values_hash
-          create_scope = scoped_where ? @scope[:create].merge(scoped_where) : @scope[:create]
-          record = @reflection.klass.send(:with_scope, :create => create_scope) do
-            @reflection.build_association(attrs)
-          end
-          if block_given?
-            add_record_to_target_with_callbacks(record) { |*block_args| yield(*block_args) }
-          else
-            add_record_to_target_with_callbacks(record)
-          end
-        end
-
-        def build_record(attrs)
-          attrs.update(@reflection.options[:conditions]) if @reflection.options[:conditions].is_a?(Hash)
-          record = @reflection.build_association(attrs)
-          if block_given?
-            add_record_to_target_with_callbacks(record) { |*block_args| yield(*block_args) }
-          else
-            add_record_to_target_with_callbacks(record)
-          end
-        end
-
-        def remove_records(*records)
-          records = flatten_deeper(records)
-          records.each { |record| raise_on_type_mismatch(record) }
-
-          transaction do
-            records.each { |record| callback(:before_remove, record) }
-            old_records = records.reject { |r| r.new_record? }
-            yield(records, old_records)
-            records.each { |record| callback(:after_remove, record) }
-          end
-        end
-
-        def callback(method, record)
-          callbacks_for(method).each do |callback|
-            case callback
-            when Symbol
-              @owner.send(callback, record)
-            when Proc
-              callback.call(@owner, record)
-            else
-              callback.send(method, @owner, record)
-            end
-          end
-        end
-
-        def callbacks_for(callback_name)
-          full_callback_name = "#{callback_name}_for_#{@reflection.name}"
-          @owner.class.send(full_callback_name.to_sym) || []
-        end
-
-        def ensure_owner_is_persisted!
-          unless @owner.persisted?
-            raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
-          end
-        end
-
-        def fetch_first_or_last_using_find?(args)
-          (args.first.kind_of?(Hash) && !args.first.empty?) || !(loaded? || @owner.new_record? || @reflection.options[:finder_sql] ||
-            @target.any? { |record| record.new_record? } || args.first.kind_of?(Integer))
-        end
-
-        def include_in_memory?(record)
-          if @reflection.is_a?(ActiveRecord::Reflection::ThroughReflection)
-            @owner.send(proxy_reflection.through_reflection.name.to_sym).any? do |source|
-              target = source.send(proxy_reflection.source_reflection.name)
-              target.respond_to?(:include?) ? target.include?(record) : target == record
-            end
-          else
-            @target.include?(record)
-          end
-        end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
deleted file mode 100644
index 252ff7e7ea..0000000000
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ /dev/null
@@ -1,314 +0,0 @@
-require 'active_support/core_ext/array/wrap'
-
-module ActiveRecord
-  module Associations
-    # = Active Record Associations
-    #
-    # This is the root class of all association proxies:
-    #
-    #   AssociationProxy
-    #     BelongsToAssociation
-    #       HasOneAssociation
-    #     BelongsToPolymorphicAssociation
-    #     AssociationCollection
-    #       HasAndBelongsToManyAssociation
-    #       HasManyAssociation
-    #         HasManyThroughAssociation
-    #            HasOneThroughAssociation
-    #
-    # 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.find(: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 has most of the basic instance methods removed, and delegates
-    # unknown methods to <tt>@target</tt> via <tt>method_missing</tt>. As a
-    # corner case, it even removes the +class+ method and that's why you get
-    #
-    #   blog.posts.class # => Array
-    #
-    # though the object behind <tt>blog.posts</tt> is not an Array, but an
-    # ActiveRecord::Associations::HasManyAssociation.
-    #
-    # 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 AssociationProxy #:nodoc:
-      alias_method :proxy_respond_to?, :respond_to?
-      alias_method :proxy_extend, :extend
-      delegate :to_param, :to => :proxy_target
-      instance_methods.each { |m| undef_method m unless m.to_s =~ /^(?:nil\?|send|object_id|to_a)$|^__|^respond_to_missing|proxy_/ }
-
-      def initialize(owner, reflection)
-        @owner, @reflection = owner, reflection
-        @updated = false
-        reflection.check_validity!
-        Array.wrap(reflection.options[:extend]).each { |ext| proxy_extend(ext) }
-        reset
-        construct_scope
-      end
-
-      # Returns the owner of the proxy.
-      def proxy_owner
-        @owner
-      end
-
-      # Returns the reflection object that represents the association handled
-      # by the proxy.
-      def proxy_reflection
-        @reflection
-      end
-
-      # Returns the \target of the proxy, same as +target+.
-      def proxy_target
-        @target
-      end
-
-      # Does the proxy or its \target respond to +symbol+?
-      def respond_to?(*args)
-        proxy_respond_to?(*args) || (load_target && @target.respond_to?(*args))
-      end
-
-      # Forwards <tt>===</tt> explicitly to the \target because the instance method
-      # removal above doesn't catch it. Loads the \target if needed.
-      def ===(other)
-        load_target
-        other === @target
-      end
-
-      # Returns the name of the table of the related class:
-      #
-      #   post.comments.aliased_table_name # => "comments"
-      #
-      def aliased_table_name
-        @reflection.klass.table_name
-      end
-
-      # Returns the SQL string that corresponds to the <tt>:conditions</tt>
-      # option of the macro, if given, or +nil+ otherwise.
-      def conditions
-        @conditions ||= interpolate_sql(@reflection.sanitized_conditions) if @reflection.sanitized_conditions
-      end
-      alias :sql_conditions :conditions
-
-      # Resets the \loaded flag to +false+ and sets the \target to +nil+.
-      def reset
-        @loaded = false
-        @target = nil
-      end
-
-      # Reloads the \target and returns +self+ on success.
-      def reload
-        reset
-        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
-      end
-
-      # Returns the target of this proxy, same as +proxy_target+.
-      def target
-        @target
-      end
-
-      # Sets the target of this proxy to <tt>\target</tt>, and the \loaded flag to +true+.
-      def target=(target)
-        @target = target
-        loaded
-      end
-
-      # Forwards the call to the target. Loads the \target if needed.
-      def inspect
-        load_target
-        @target.inspect
-      end
-
-      def send(method, *args)
-        if proxy_respond_to?(method)
-          super
-        else
-          load_target
-          @target.send(method, *args)
-        end
-      end
-
-      protected
-        # Does the association have a <tt>:dependent</tt> option?
-        def dependent?
-          @reflection.options[:dependent]
-        end
-
-        def interpolate_sql(sql, record = nil)
-          @owner.send(:interpolate_sql, sql, record)
-        end
-
-        # Forwards the call to the reflection class.
-        def sanitize_sql(sql, table_name = @reflection.klass.table_name)
-          @reflection.klass.send(:sanitize_sql, sql, table_name)
-        end
-
-        # Assigns the ID of the owner to the corresponding foreign key in +record+.
-        # If the association is polymorphic the type of the owner is also set.
-        def set_belongs_to_association_for(record)
-          if @reflection.options[:as]
-            record["#{@reflection.options[:as]}_id"]   = @owner.id if @owner.persisted?
-            record["#{@reflection.options[:as]}_type"] = @owner.class.base_class.name.to_s
-          else
-            if @owner.persisted?
-              primary_key = @reflection.options[:primary_key] || :id
-              record[@reflection.primary_key_name] = @owner.send(primary_key)
-            end
-          end
-        end
-
-        # Merges into +options+ the ones coming from the reflection.
-        def merge_options_from_reflection!(options)
-          options.reverse_merge!(
-            :group   => @reflection.options[:group],
-            :having  => @reflection.options[:having],
-            :limit   => @reflection.options[:limit],
-            :offset  => @reflection.options[:offset],
-            :joins   => @reflection.options[:joins],
-            :include => @reflection.options[:include],
-            :select  => @reflection.options[:select],
-            :readonly  => @reflection.options[:readonly]
-          )
-        end
-
-        # Forwards +with_scope+ to the reflection.
-        def with_scope(*args, &block)
-          @reflection.klass.send :with_scope, *args, &block
-        end
-
-        # Construct the scope used for find/create queries on the target
-        def construct_scope
-          @scope = {
-            :find   => construct_find_scope,
-            :create => construct_create_scope
-          }
-        end
-
-        # Implemented by subclasses
-        def construct_find_scope
-          raise NotImplementedError
-        end
-
-        # Implemented by (some) subclasses
-        def construct_create_scope
-          {}
-        end
-
-      private
-        # Forwards any missing method call to the \target.
-        def method_missing(method, *args)
-          if load_target
-            unless @target.respond_to?(method)
-              message = "undefined method `#{method.to_s}' for \"#{@target}\":#{@target.class.to_s}"
-              raise NoMethodError, message
-            end
-
-            if block_given?
-              @target.send(method, *args)  { |*block_args| yield(*block_args) }
-            else
-              @target.send(method, *args)
-            end
-          end
-        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
-          return nil unless defined?(@loaded)
-
-          if !loaded? && (!@owner.new_record? || foreign_key_present)
-            @target = find_target
-          end
-
-          @loaded = true
-          @target
-        rescue ActiveRecord::RecordNotFound
-          reset
-        end
-
-        # Can be overwritten by associations that might have the foreign key
-        # available for an association without having the object itself (and
-        # still being a new record). Currently, only +belongs_to+ presents
-        # this scenario (both vanilla and polymorphic).
-        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
-
-        if RUBY_VERSION < '1.9.2'
-          # Array#flatten has problems with recursive arrays before Ruby 1.9.2.
-          # Going one level deeper solves the majority of the problems.
-          def flatten_deeper(array)
-            array.collect { |element| (element.respond_to?(:flatten) && !element.is_a?(Hash)) ? element.flatten : element }.flatten
-          end
-        else
-          def flatten_deeper(array)
-            array.flatten
-          end
-        end
-
-        # Returns the ID of the owner, quoted if needed.
-        def owner_quoted_id
-          @owner.quoted_id
-        end
-
-        def set_inverse_instance(record, instance)
-          return if record.nil? || !we_can_set_the_inverse_on_this?(record)
-          inverse_relationship = @reflection.inverse_of
-          unless inverse_relationship.nil?
-            record.send(:"set_#{inverse_relationship.name}_target", instance)
-          end
-        end
-
-        # Override in subclasses
-        def we_can_set_the_inverse_on_this?(record)
-          false
-        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
index b438620c8f..c263edd2c6 100644
--- a/activerecord/lib/active_record/associations/belongs_to_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -1,41 +1,17 @@
 module ActiveRecord
   # = Active Record Belongs To Associations
   module Associations
-    class BelongsToAssociation < AssociationProxy #:nodoc:
-      def create(attributes = {})
-        replace(@reflection.create_association(attributes))
-      end
-
-      def build(attributes = {})
-        replace(@reflection.build_association(attributes))
-      end
-
+    class BelongsToAssociation < SingularAssociation #:nodoc:
       def replace(record)
-        counter_cache_name = @reflection.counter_cache_column
-
-        if record.nil?
-          if counter_cache_name && @owner.persisted?
-            @reflection.klass.decrement_counter(counter_cache_name, previous_record_id) if @owner[@reflection.primary_key_name]
-          end
-
-          @target = @owner[@reflection.primary_key_name] = nil
-        else
-          raise_on_type_mismatch(record)
+        raise_on_type_mismatch(record) if record
 
-          if counter_cache_name && @owner.persisted? && record.id != @owner[@reflection.primary_key_name]
-            @reflection.klass.increment_counter(counter_cache_name, record.id)
-            @reflection.klass.decrement_counter(counter_cache_name, @owner[@reflection.primary_key_name]) if @owner[@reflection.primary_key_name]
-          end
-
-          @target = (AssociationProxy === record ? record.target : record)
-          @owner[@reflection.primary_key_name] = record_id(record) if record.persisted?
-          @updated = true
-        end
+        update_counters(record)
+        replace_keys(record)
+        set_inverse_instance(record)
 
-        set_inverse_instance(record, @owner)
+        @updated = true if record
 
-        loaded
-        record
+        self.target = record
       end
 
       def updated?
@@ -43,50 +19,52 @@ module ActiveRecord
       end
 
       private
-        def find_target
-          find_method = if @reflection.options[:primary_key]
-                          "find_by_#{@reflection.options[:primary_key]}"
-                        else
-                          "find"
-                        end
 
-          options = @reflection.options.dup.slice(:select, :include, :readonly)
+        def update_counters(record)
+          counter_cache_name = reflection.counter_cache_column
+
+          if counter_cache_name && owner.persisted? && different_target?(record)
+            if record
+              record.class.increment_counter(counter_cache_name, record.id)
+            end
 
-          the_target = with_scope(:find => @scope[:find]) do
-            @reflection.klass.send(find_method,
-              @owner[@reflection.primary_key_name],
-              options
-            ) if @owner[@reflection.primary_key_name]
+            if foreign_key_present?
+              klass.decrement_counter(counter_cache_name, target_id)
+            end
           end
-          set_inverse_instance(the_target, @owner)
-          the_target
         end
 
-        def construct_find_scope
-          { :conditions => conditions }
+        # Checks whether record is different to the current target, without loading it
+        def different_target?(record)
+          record.nil? && owner[reflection.foreign_key] ||
+          record.id   != owner[reflection.foreign_key]
         end
 
-        def foreign_key_present
-          !@owner[@reflection.primary_key_name].nil?
+        def replace_keys(record)
+          owner[reflection.foreign_key] = record && record[reflection.association_primary_key]
+        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 we_can_set_the_inverse_on_this?(record)
-          @reflection.has_inverse? && @reflection.inverse_of.macro == :has_one
+        def invertible_for?(record)
+          inverse = inverse_reflection_for(record)
+          inverse && inverse.macro == :has_one
         end
 
-        def record_id(record)
-          record.send(@reflection.options[:primary_key] || :id)
+        def target_id
+          if options[:primary_key]
+            owner.send(reflection.name).try(:id)
+          else
+            owner[reflection.foreign_key]
+          end
         end
 
-        def previous_record_id
-          @previous_record_id ||= if @reflection.options[:primary_key]
-                                    previous_record = @owner.send(@reflection.name)
-                                    previous_record.nil? ? nil : previous_record.id
-                                  else
-                                    @owner[@reflection.primary_key_name]
-                                  end
+        def stale_state
+          owner[reflection.foreign_key].to_s
         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
index a0df860623..1ca448236e 100644
--- a/activerecord/lib/active_record/associations/belongs_to_polymorphic_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_polymorphic_association.rb
@@ -1,77 +1,33 @@
 module ActiveRecord
   # = Active Record Belongs To Polymorphic Association
   module Associations
-    class BelongsToPolymorphicAssociation < AssociationProxy #:nodoc:
-      def replace(record)
-        if record.nil?
-          @target = @owner[@reflection.primary_key_name] = @owner[@reflection.options[:foreign_type]] = nil
-        else
-          @target = (AssociationProxy === record ? record.target : record)
-
-          @owner[@reflection.primary_key_name] = record_id(record)
-          @owner[@reflection.options[:foreign_type]] = record.class.base_class.name.to_s
-
-          @updated = true
-        end
-
-        set_inverse_instance(record, @owner)
-        loaded
-        record
-      end
-
-      def updated?
-        @updated
-      end
-
+    class BelongsToPolymorphicAssociation < BelongsToAssociation #:nodoc:
       private
 
-        # NOTE - for now, we're only supporting inverse setting from belongs_to back onto
-        # has_one associations.
-        def we_can_set_the_inverse_on_this?(record)
-          if @reflection.has_inverse?
-            inverse_association = @reflection.polymorphic_inverse_of(record.class)
-            inverse_association && inverse_association.macro == :has_one
-          else
-            false
-          end
-        end
-
-        def set_inverse_instance(record, instance)
-          return if record.nil? || !we_can_set_the_inverse_on_this?(record)
-          inverse_relationship = @reflection.polymorphic_inverse_of(record.class)
-          if inverse_relationship
-            record.send(:"set_#{inverse_relationship.name}_target", instance)
-          end
+        def replace_keys(record)
+          super
+          owner[reflection.foreign_type] = record && record.class.base_class.name
         end
 
-        def construct_find_scope
-          { :conditions => conditions }
+        def different_target?(record)
+          super || record.class != klass
         end
 
-        def find_target
-          return nil if association_class.nil?
-
-          target = association_class.send(:with_scope, :find => @scope[:find]) do
-            association_class.find(
-              @owner[@reflection.primary_key_name],
-              :select  => @reflection.options[:select],
-              :include => @reflection.options[:include]
-            )
-          end
-          set_inverse_instance(target, @owner)
-          target
+        def inverse_reflection_for(record)
+          reflection.polymorphic_inverse_of(record.class)
         end
 
-        def foreign_key_present
-          !@owner[@reflection.primary_key_name].nil?
+        def klass
+          type = owner[reflection.foreign_type]
+          type && type.constantize
         end
 
-        def record_id(record)
-          record.send(@reflection.options[:primary_key] || :id)
+        def raise_on_type_mismatch(record)
+          # A polymorphic association cannot have a type mismatch, by definition
         end
 
-        def association_class
-          @owner[@reflection.options[:foreign_type]] ? @owner[@reflection.options[:foreign_type]].constantize : nil
+        def stale_state
+          [super, owner[reflection.foreign_type].to_s]
         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..96fca97440
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/association.rb
@@ -0,0 +1,53 @@
+module ActiveRecord::Associations::Builder
+  class Association #:nodoc:
+    class_attribute :valid_options
+    self.valid_options = [:class_name, :foreign_key, :select, :conditions, :include, :extend, :readonly, :validate]
+
+    # Set by subclasses
+    class_attribute :macro
+
+    attr_reader :model, :name, :options, :reflection
+
+    def self.build(model, name, options)
+      new(model, name, options).build
+    end
+
+    def initialize(model, name, options)
+      @model, @name, @options = model, name, options
+    end
+
+    def build
+      validate_options
+      reflection = model.create_reflection(self.class.macro, name, options, model)
+      define_accessors
+      reflection
+    end
+
+    private
+
+      def validate_options
+        options.assert_valid_keys(self.class.valid_options)
+      end
+
+      def define_accessors
+        define_readers
+        define_writers
+      end
+
+      def define_readers
+        name = self.name
+
+        model.redefine_method(name) do |*params|
+          association(name).reader(*params)
+        end
+      end
+
+      def define_writers
+        name = self.name
+
+        model.redefine_method("#{name}=") do |value|
+          association(name).writer(value)
+        end
+      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..964e7fddc8
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/belongs_to.rb
@@ -0,0 +1,83 @@
+module ActiveRecord::Associations::Builder
+  class BelongsTo < SingularAssociation #:nodoc:
+    self.macro = :belongs_to
+
+    self.valid_options += [:foreign_type, :polymorphic, :touch]
+
+    def constructable?
+      !options[:polymorphic]
+    end
+
+    def build
+      reflection = super
+      add_counter_cache_callbacks(reflection) if options[:counter_cache]
+      add_touch_callbacks(reflection)         if options[:touch]
+      configure_dependency
+      reflection
+    end
+
+    private
+
+      def add_counter_cache_callbacks(reflection)
+        cache_column = reflection.counter_cache_column
+        name         = self.name
+
+        method_name = "belongs_to_counter_cache_after_create_for_#{name}"
+        model.redefine_method(method_name) do
+          record = send(name)
+          record.class.increment_counter(cache_column, record.id) unless record.nil?
+        end
+        model.after_create(method_name)
+
+        method_name = "belongs_to_counter_cache_before_destroy_for_#{name}"
+        model.redefine_method(method_name) do
+          record = send(name)
+          record.class.decrement_counter(cache_column, record.id) unless record.nil?
+        end
+        model.before_destroy(method_name)
+
+        model.send(:module_eval,
+          "#{reflection.class_name}.send(:attr_readonly,\"#{cache_column}\".intern) if defined?(#{reflection.class_name}) && #{reflection.class_name}.respond_to?(:attr_readonly)", __FILE__, __LINE__
+        )
+      end
+
+      def add_touch_callbacks(reflection)
+        name        = self.name
+        method_name = "belongs_to_touch_after_save_or_destroy_for_#{name}"
+        touch       = options[:touch]
+
+        model.redefine_method(method_name) do
+          record = send(name)
+
+          unless record.nil?
+            if touch == true
+              record.touch
+            else
+              record.touch(touch)
+            end
+          end
+        end
+
+        model.after_save(method_name)
+        model.after_touch(method_name)
+        model.after_destroy(method_name)
+      end
+
+      def configure_dependency
+        if options[:dependent]
+          unless [:destroy, :delete].include?(options[:dependent])
+            raise ArgumentError, "The :dependent option expects either :destroy or :delete (#{options[:dependent].inspect})"
+          end
+
+          method_name = "belongs_to_dependent_#{options[:dependent]}_for_#{name}"
+          model.send(:class_eval, <<-eoruby, __FILE__, __LINE__ + 1)
+            def #{method_name}
+              association = #{name}
+              association.#{options[:dependent]} if association
+            end
+          eoruby
+          model.after_destroy method_name
+        end
+      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..f62209a226
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/collection_association.rb
@@ -0,0 +1,75 @@
+module ActiveRecord::Associations::Builder
+  class CollectionAssociation < Association #:nodoc:
+    CALLBACKS = [:before_add, :after_add, :before_remove, :after_remove]
+
+    self.valid_options += [
+      :table_name, :order, :group, :having, :limit, :offset, :uniq, :finder_sql,
+      :counter_sql, :before_add, :after_add, :before_remove, :after_remove
+    ]
+
+    attr_reader :block_extension
+
+    def self.build(model, name, options, &extension)
+      new(model, name, options, &extension).build
+    end
+
+    def initialize(model, name, options, &extension)
+      super(model, name, options)
+      @block_extension = extension
+    end
+
+    def build
+      wrap_block_extension
+      reflection = super
+      CALLBACKS.each { |callback_name| define_callback(callback_name) }
+      reflection
+    end
+
+    def writable?
+      true
+    end
+
+    private
+
+      def wrap_block_extension
+        options[:extend] = Array.wrap(options[:extend])
+
+        if block_extension
+          silence_warnings do
+            model.parent.const_set(extension_module_name, Module.new(&block_extension))
+          end
+          options[:extend].push("#{model.parent}::#{extension_module_name}".constantize)
+        end
+      end
+
+      def extension_module_name
+        @extension_module_name ||= "#{model.to_s.demodulize}#{name.to_s.camelize}AssociationExtension"
+      end
+
+      def define_callback(callback_name)
+        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.to_sym unless model.method_defined?(full_callback_name)
+        model.send("#{full_callback_name}=", Array.wrap(options[callback_name.to_sym]))
+      end
+
+      def define_readers
+        super
+
+        name = self.name
+        model.redefine_method("#{name.to_s.singularize}_ids") do
+          association(name).ids_reader
+        end
+      end
+
+      def define_writers
+        super
+
+        name = self.name
+        model.redefine_method("#{name.to_s.singularize}_ids=") do |ids|
+          association(name).ids_writer(ids)
+        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..e40b32826a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
@@ -0,0 +1,63 @@
+module ActiveRecord::Associations::Builder
+  class HasAndBelongsToMany < CollectionAssociation #:nodoc:
+    self.macro = :has_and_belongs_to_many
+
+    self.valid_options += [:join_table, :association_foreign_key, :delete_sql, :insert_sql]
+
+    def build
+      reflection = super
+      check_validity(reflection)
+      redefine_destroy
+      reflection
+    end
+
+    private
+
+      def redefine_destroy
+        # Don't use a before_destroy callback since users' before_destroy
+        # callbacks will be executed after the association is wiped out.
+        name = self.name
+        model.send(:include, Module.new {
+          class_eval <<-RUBY, __FILE__, __LINE__ + 1
+            def destroy          # def destroy
+              super              #   super
+              #{name}.clear      #   posts.clear
+            end                  # end
+          RUBY
+        })
+      end
+
+      # TODO: These checks should probably be moved into the Reflection, and we should not be
+      #       redefining the options[:join_table] value - instead we should define a
+      #       reflection.join_table method.
+      def check_validity(reflection)
+        if reflection.association_foreign_key == reflection.foreign_key
+          raise ActiveRecord::HasAndBelongsToManyAssociationForeignKeyNeeded.new(reflection)
+        end
+
+        reflection.options[:join_table] ||= join_table_name(
+          model.send(:undecorated_table_name, model.to_s),
+          model.send(:undecorated_table_name, reflection.class_name)
+        )
+
+        if model.connection.supports_primary_key? && (model.connection.primary_key(reflection.options[:join_table]) rescue false)
+          raise ActiveRecord::HasAndBelongsToManyAssociationWithPrimaryKeyError.new(reflection)
+        end
+      end
+
+      # Generates a join table name from two provided table names.
+      # The names in the join table names end up in lexicographic order.
+      #
+      #   join_table_name("members", "clubs")         # => "clubs_members"
+      #   join_table_name("members", "special_clubs") # => "members_special_clubs"
+      def join_table_name(first_table_name, second_table_name)
+        if first_table_name < second_table_name
+          join_table = "#{first_table_name}_#{second_table_name}"
+        else
+          join_table = "#{second_table_name}_#{first_table_name}"
+        end
+
+        model.table_name_prefix + join_table + model.table_name_suffix
+      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..77bb66228d
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_many.rb
@@ -0,0 +1,63 @@
+module ActiveRecord::Associations::Builder
+  class HasMany < CollectionAssociation #:nodoc:
+    self.macro = :has_many
+
+    self.valid_options += [:primary_key, :dependent, :as, :through, :source, :source_type, :inverse_of]
+
+    def build
+      reflection = super
+      configure_dependency
+      reflection
+    end
+
+    private
+
+      def configure_dependency
+        if options[:dependent]
+          unless [:destroy, :delete_all, :nullify, :restrict].include?(options[:dependent])
+            raise ArgumentError, "The :dependent option expects either :destroy, :delete_all, " \
+                                 ":nullify or :restrict (#{options[:dependent].inspect})"
+          end
+
+          send("define_#{options[:dependent]}_dependency_method")
+          model.before_destroy dependency_method_name
+        end
+      end
+
+      def define_destroy_dependency_method
+        name = self.name
+        model.send(:define_method, dependency_method_name) do
+          send(name).each do |o|
+            # No point in executing the counter update since we're going to destroy the parent anyway
+            counter_method = ('belongs_to_counter_cache_before_destroy_for_' + self.class.name.downcase).to_sym
+            if o.respond_to?(counter_method)
+              class << o
+                self
+              end.send(:define_method, counter_method, Proc.new {})
+            end
+          end
+
+          send(name).delete_all
+        end
+      end
+
+      def define_delete_all_dependency_method
+        name = self.name
+        model.send(:define_method, dependency_method_name) do
+          send(name).delete_all
+        end
+      end
+      alias :define_nullify_dependency_method :define_delete_all_dependency_method
+
+      def define_restrict_dependency_method
+        name = self.name
+        model.send(:define_method, dependency_method_name) do
+          raise ActiveRecord::DeleteRestrictionError.new(name) unless send(name).empty?
+        end
+      end
+
+      def dependency_method_name
+        "has_many_dependent_for_#{name}"
+      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..07ba5d088e
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/has_one.rb
@@ -0,0 +1,61 @@
+module ActiveRecord::Associations::Builder
+  class HasOne < SingularAssociation #:nodoc:
+    self.macro = :has_one
+
+    self.valid_options += [:order, :as]
+
+    class_attribute :through_options
+    self.through_options = [:through, :source, :source_type]
+
+    def constructable?
+      !options[:through]
+    end
+
+    def build
+      reflection = super
+      configure_dependency unless options[:through]
+      reflection
+    end
+
+    private
+
+      def validate_options
+        valid_options = self.class.valid_options
+        valid_options += self.class.through_options if options[:through]
+        options.assert_valid_keys(valid_options)
+      end
+
+      def configure_dependency
+        if options[:dependent]
+          unless [:destroy, :delete, :nullify, :restrict].include?(options[:dependent])
+            raise ArgumentError, "The :dependent option expects either :destroy, :delete, " \
+                                 ":nullify or :restrict (#{options[:dependent].inspect})"
+          end
+
+          send("define_#{options[:dependent]}_dependency_method")
+          model.before_destroy dependency_method_name
+        end
+      end
+
+      def dependency_method_name
+        "has_one_dependent_#{options[:dependent]}_for_#{name}"
+      end
+
+      def define_destroy_dependency_method
+        model.send(:class_eval, <<-eoruby, __FILE__, __LINE__ + 1)
+          def #{dependency_method_name}
+            association(#{name.to_sym.inspect}).delete
+          end
+        eoruby
+      end
+      alias :define_delete_dependency_method :define_destroy_dependency_method
+      alias :define_nullify_dependency_method :define_destroy_dependency_method
+
+      def define_restrict_dependency_method
+        name = self.name
+        model.redefine_method(dependency_method_name) do
+          raise ActiveRecord::DeleteRestrictionError.new(name) unless send(name).nil?
+        end
+      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..06a414b874
--- /dev/null
+++ b/activerecord/lib/active_record/associations/builder/singular_association.rb
@@ -0,0 +1,32 @@
+module ActiveRecord::Associations::Builder
+  class SingularAssociation < Association #:nodoc:
+    self.valid_options += [:remote, :dependent, :counter_cache, :primary_key, :inverse_of]
+
+    def constructable?
+      true
+    end
+
+    def define_accessors
+      super
+      define_constructors if constructable?
+    end
+
+    private
+
+      def define_constructors
+        name = self.name
+
+        model.redefine_method("build_#{name}") do |*params|
+          association(name).build(*params)
+        end
+
+        model.redefine_method("create_#{name}") do |*params|
+          association(name).create(*params)
+        end
+
+        model.redefine_method("create_#{name}!") do |*params|
+          association(name).create!(*params)
+        end
+      end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency.rb
deleted file mode 100644
index 78b634a26c..0000000000
--- a/activerecord/lib/active_record/associations/class_methods/join_dependency.rb
+++ /dev/null
@@ -1,216 +0,0 @@
-require 'active_record/associations/class_methods/join_dependency/join_part'
-require 'active_record/associations/class_methods/join_dependency/join_base'
-require 'active_record/associations/class_methods/join_dependency/join_association'
-
-module ActiveRecord
-  module Associations
-    module ClassMethods
-      class JoinDependency # :nodoc:
-        attr_reader :join_parts, :reflections, :alias_tracker, :active_record
-
-        def initialize(base, associations, joins)
-          @active_record = base
-          @table_joins   = joins
-          @join_parts    = [JoinBase.new(base)]
-          @associations  = {}
-          @reflections   = []
-          @alias_tracker = AliasTracker.new(joins)
-          @alias_tracker.aliased_name_for(base.table_name) # Updates the count for base.table_name to 1
-          build(associations)
-        end
-
-        def graft(*associations)
-          associations.each do |association|
-            join_associations.detect {|a| association == a} ||
-              build(association.reflection.name, association.find_parent_in(self) || join_base, association.join_type)
-          end
-          self
-        end
-
-        def join_associations
-          join_parts.last(join_parts.length - 1)
-        end
-
-        def join_base
-          join_parts.first
-        end
-
-        def columns
-          join_parts.collect { |join_part|
-            table = join_part.aliased_table
-            join_part.column_names_with_alias.collect{ |column_name, aliased_name|
-              table[column_name].as Arel.sql(aliased_name)
-            }
-          }.flatten
-        end
-
-        def instantiate(rows)
-          primary_key = join_base.aliased_primary_key
-          parents = {}
-
-          records = rows.map { |model|
-            primary_id = model[primary_key]
-            parent = parents[primary_id] ||= join_base.instantiate(model)
-            construct(parent, @associations, join_associations, model)
-            parent
-          }.uniq
-
-          remove_duplicate_results!(active_record, records, @associations)
-          records
-        end
-
-        def remove_duplicate_results!(base, records, associations)
-          case associations
-          when Symbol, String
-            reflection = base.reflections[associations]
-            remove_uniq_by_reflection(reflection, records)
-          when Array
-            associations.each do |association|
-              remove_duplicate_results!(base, records, association)
-            end
-          when Hash
-            associations.keys.each do |name|
-              reflection = base.reflections[name]
-              remove_uniq_by_reflection(reflection, records)
-
-              parent_records = []
-              records.each do |record|
-                if descendant = record.send(reflection.name)
-                  if reflection.collection?
-                    parent_records.concat descendant.target.uniq
-                  else
-                    parent_records << descendant
-                  end
-                end
-              end
-
-              remove_duplicate_results!(reflection.klass, parent_records, associations[name]) unless parent_records.empty?
-            end
-          end
-        end
-
-        protected
-
-        def cache_joined_association(association)
-          associations = []
-          parent = association.parent
-          while parent != join_base
-            associations.unshift(parent.reflection.name)
-            parent = parent.parent
-          end
-          ref = @associations
-          associations.each do |key|
-            ref = ref[key]
-          end
-          ref[association.reflection.name] ||= {}
-        end
-
-        def build(associations, parent = nil, join_type = Arel::InnerJoin)
-          parent ||= join_parts.last
-          case associations
-          when Symbol, String
-            reflection = parent.reflections[associations.to_s.intern] or
-            raise ConfigurationError, "Association named '#{ associations }' was not found; perhaps you misspelled it?"
-            unless join_association = find_join_association(reflection, parent)
-              @reflections << reflection
-              join_association = build_join_association(reflection, parent)
-              join_association.join_type = join_type
-              @join_parts << join_association
-              cache_joined_association(join_association)
-            end
-            join_association
-          when Array
-            associations.each do |association|
-              build(association, parent, join_type)
-            end
-          when Hash
-            associations.keys.sort_by { |a| a.to_s }.each do |name|
-              join_association = build(name, parent, join_type)
-              build(associations[name], join_association, join_type)
-            end
-          else
-            raise ConfigurationError, associations.inspect
-          end
-        end
-
-        def find_join_association(name_or_reflection, parent)
-          if String === name_or_reflection
-            name_or_reflection = name_or_reflection.to_sym
-          end
-
-          join_associations.detect { |j|
-            j.reflection == name_or_reflection && j.parent == parent
-          }
-        end
-
-        def remove_uniq_by_reflection(reflection, records)
-          if reflection && reflection.collection?
-            records.each { |record| record.send(reflection.name).target.uniq! }
-          end
-        end
-
-        def build_join_association(reflection, parent)
-          JoinAssociation.new(reflection, self, parent)
-        end
-
-        def construct(parent, associations, join_parts, row)
-          case associations
-          when Symbol, String
-            name = associations.to_s
-
-            join_part = join_parts.detect { |j|
-              j.reflection.name.to_s == name &&
-                j.parent_table_name    == parent.class.table_name }
-
-              raise(ConfigurationError, "No such association") unless join_part
-
-              join_parts.delete(join_part)
-              construct_association(parent, join_part, row)
-          when Array
-            associations.each do |association|
-              construct(parent, association, join_parts, row)
-            end
-          when Hash
-            associations.sort_by { |k,_| k.to_s }.each do |name, assoc|
-              association = construct(parent, name, join_parts, row)
-              construct(association, assoc, join_parts, row) if association
-            end
-          else
-            raise ConfigurationError, associations.inspect
-          end
-        end
-
-        def construct_association(record, join_part, row)
-          return if record.id.to_s != join_part.parent.record_id(row).to_s
-
-          macro = join_part.reflection.macro
-          if macro == :has_one
-            return if record.instance_variable_defined?("@#{join_part.reflection.name}")
-            association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil?
-            set_target_and_inverse(join_part, association, record)
-          else
-            return if row[join_part.aliased_primary_key].nil?
-            association = join_part.instantiate(row)
-            case macro
-            when :has_many, :has_and_belongs_to_many
-              collection = record.send(join_part.reflection.name)
-              collection.loaded
-              collection.target.push(association)
-              collection.__send__(:set_inverse_instance, association, record)
-            when :belongs_to
-              set_target_and_inverse(join_part, association, record)
-            else
-              raise ConfigurationError, "unknown macro: #{join_part.reflection.macro}"
-            end
-          end
-          association
-        end
-
-        def set_target_and_inverse(join_part, association, record)
-          association_proxy = record.send("set_#{join_part.reflection.name}_target", association)
-          association_proxy.__send__(:set_inverse_instance, association, record)
-        end
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
deleted file mode 100644
index 5cc96a7aef..0000000000
--- a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
+++ /dev/null
@@ -1,258 +0,0 @@
-module ActiveRecord
-  module Associations
-    module ClassMethods
-      class JoinDependency # :nodoc:
-        class JoinAssociation < JoinPart # :nodoc:
-          # The reflection of the association represented
-          attr_reader :reflection
-
-          # The JoinDependency object which this JoinAssociation exists within. This is mainly
-          # relevant for generating aliases which do not conflict with other joins which are
-          # part of the query.
-          attr_reader :join_dependency
-
-          # A JoinBase instance representing the active record we are joining onto.
-          # (So in Author.has_many :posts, the Author would be that base record.)
-          attr_reader :parent
-
-          # What type of join will be generated, either Arel::InnerJoin (default) or Arel::OuterJoin
-          attr_accessor :join_type
-
-          attr_reader :aliased_prefix
-
-          delegate :options, :through_reflection, :source_reflection, :through_reflection_chain, :to => :reflection
-          delegate :table, :table_name, :to => :parent, :prefix => :parent
-          delegate :alias_tracker, :to => :join_dependency
-
-          def initialize(reflection, join_dependency, parent = nil)
-            reflection.check_validity!
-
-            if reflection.options[:polymorphic]
-              raise EagerLoadPolymorphicError.new(reflection)
-            end
-
-            super(reflection.klass)
-
-            @reflection         = reflection
-            @join_dependency    = join_dependency
-            @parent             = parent
-            @join_type          = Arel::InnerJoin
-            @aliased_prefix     = "t#{ join_dependency.join_parts.size }"
-
-            setup_tables
-          end
-
-          def ==(other)
-            other.class == self.class &&
-              other.reflection == reflection &&
-              other.parent == parent
-          end
-
-          def find_parent_in(other_join_dependency)
-            other_join_dependency.join_parts.detect do |join_part|
-              parent == join_part
-            end
-          end
-
-          def join_to(relation)
-            # The chain starts with the target table, but we want to end with it here (makes
-            # more sense in this context)
-            chain = through_reflection_chain.reverse
-
-            foreign_table = parent_table
-            index = 0
-
-            chain.each do |reflection|
-              table = @tables[index]
-              conditions = []
-
-              if reflection.source_reflection.nil?
-                case reflection.macro
-                  when :belongs_to
-                    key         = reflection.association_primary_key
-                    foreign_key = reflection.primary_key_name
-                  when :has_many, :has_one
-                    key         = reflection.primary_key_name
-                    foreign_key = reflection.active_record_primary_key
-
-                    conditions << polymorphic_conditions(reflection, table)
-                  when :has_and_belongs_to_many
-                    # For habtm, we need to deal with the join table at the same time as the
-                    # target table (because unlike a :through association, there is no reflection
-                    # to represent the join table)
-                    table, join_table = table
-
-                    join_key         = reflection.primary_key_name
-                    join_foreign_key = reflection.active_record.primary_key
-
-                    relation = relation.join(join_table, join_type).on(
-                      join_table[join_key].
-                        eq(foreign_table[join_foreign_key])
-                    )
-
-                    # We've done the first join now, so update the foreign_table for the second
-                    foreign_table = join_table
-
-                    key         = reflection.klass.primary_key
-                    foreign_key = reflection.association_foreign_key
-                end
-              else
-                case reflection.source_reflection.macro
-                  when :belongs_to
-                    key         = reflection.association_primary_key
-                    foreign_key = reflection.primary_key_name
-
-                    conditions << source_type_conditions(reflection, foreign_table)
-                  when :has_many, :has_one
-                    key         = reflection.primary_key_name
-                    foreign_key = reflection.source_reflection.active_record_primary_key
-                  when :has_and_belongs_to_many
-                    table, join_table = table
-
-                    join_key         = reflection.primary_key_name
-                    join_foreign_key = reflection.klass.primary_key
-
-                    relation = relation.join(join_table, join_type).on(
-                      join_table[join_key].
-                        eq(foreign_table[join_foreign_key])
-                    )
-
-                    foreign_table = join_table
-
-                    key         = reflection.klass.primary_key
-                    foreign_key = reflection.association_foreign_key
-                end
-              end
-
-              conditions << table[key].eq(foreign_table[foreign_key])
-
-              conditions << reflection_conditions(index, table)
-              conditions << sti_conditions(reflection, table)
-
-              ands = relation.create_and(conditions.flatten.compact)
-
-              join = relation.create_join(
-                relation.froms.first,
-                table,
-                relation.create_on(ands),
-                join_type)
-
-              relation = relation.from(join)
-
-              # The current table in this iteration becomes the foreign table in the next
-              foreign_table = table
-              index += 1
-            end
-
-            relation
-          end
-
-          def join_relation(joining_relation)
-            self.join_type = Arel::OuterJoin
-            joining_relation.joins(self)
-          end
-
-          def table
-            if @tables.last.is_a?(Array)
-              @tables.last.first
-            else
-              @tables.last
-            end
-          end
-
-          def aliased_table_name
-            table.table_alias || table.name
-          end
-
-          protected
-
-          def table_alias_for(reflection, join = false)
-            name = alias_tracker.pluralize(reflection.name)
-            name << "_#{parent_table_name}"
-            name << "_join" if join
-            name
-          end
-
-          private
-
-          # Generate aliases and Arel::Table instances for each of the tables which we will
-          # later generate joins for. We must do this in advance in order to correctly allocate
-          # the proper alias.
-          def setup_tables
-            @tables = through_reflection_chain.map do |reflection|
-              aliased_table_name = alias_tracker.aliased_name_for(
-                reflection.table_name,
-                table_alias_for(reflection, reflection != self.reflection)
-              )
-
-              table = Arel::Table.new(reflection.table_name, :as => aliased_table_name)
-
-              # For habtm, we have two Arel::Table instances related to a single reflection, so
-              # we just store them as a pair in the array.
-              if reflection.macro == :has_and_belongs_to_many ||
-                   (reflection.source_reflection &&
-                    reflection.source_reflection.macro == :has_and_belongs_to_many)
-
-                join_table_name = (reflection.source_reflection || reflection).options[:join_table]
-
-                aliased_join_table_name = alias_tracker.aliased_name_for(
-                  join_table_name,
-                  table_alias_for(reflection, true)
-                )
-
-                join_table = Arel::Table.new(join_table_name, :as => aliased_join_table_name)
-
-                [table, join_table]
-              else
-                table
-              end
-            end
-
-            # The joins are generated from the through_reflection_chain in reverse order, so
-            # reverse the tables too (but it's important to generate the aliases in the 'forward'
-            # order, which is why we only do the reversal now.
-            @tables.reverse!
-
-            @tables
-          end
-
-          def reflection_conditions(index, table)
-            @reflection.through_conditions.reverse[index].map do |condition|
-              Arel.sql(sanitize_sql(condition, table.table_alias || table.name))
-            end
-          end
-
-          def sanitize_sql(condition, table_name)
-            active_record.send(:sanitize_sql, condition, table_name)
-          end
-
-          def sti_conditions(reflection, table)
-            unless reflection.klass.descends_from_active_record?
-              sti_column    = table[reflection.klass.inheritance_column]
-              sti_condition = sti_column.eq(reflection.klass.sti_name)
-              subclasses    = reflection.klass.descendants
-
-              subclasses.inject(sti_condition) { |attr,subclass|
-                attr.or(sti_column.eq(subclass.sti_name))
-              }
-            end
-          end
-
-          def source_type_conditions(reflection, foreign_table)
-            if reflection.options[:source_type]
-              foreign_table[reflection.source_reflection.options[:foreign_type]].
-                eq(reflection.options[:source_type])
-            end
-          end
-
-          def polymorphic_conditions(reflection, table)
-            if reflection.options[:as]
-              table["#{reflection.options[:as]}_type"].
-                eq(reflection.active_record.base_class.name)
-            end
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_base.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_base.rb
deleted file mode 100644
index 67567f06df..0000000000
--- a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_base.rb
+++ /dev/null
@@ -1,26 +0,0 @@
-module ActiveRecord
-  module Associations
-    module ClassMethods
-      class JoinDependency # :nodoc:
-        class JoinBase < JoinPart # :nodoc:
-          def ==(other)
-            other.class == self.class &&
-              other.active_record == active_record
-          end
-
-          def aliased_prefix
-            "t0"
-          end
-
-          def table
-            Arel::Table.new(table_name, arel_engine)
-          end
-
-          def aliased_table_name
-            active_record.table_name
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_part.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_part.rb
deleted file mode 100644
index cd16ae5a8b..0000000000
--- a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_part.rb
+++ /dev/null
@@ -1,80 +0,0 @@
-module ActiveRecord
-  module Associations
-    module ClassMethods
-      class JoinDependency # :nodoc:
-        # A JoinPart represents a part of a JoinDependency. It is an abstract class, 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:
-          # 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 :active_record
-
-          delegate :table_name, :column_names, :primary_key, :reflections, :arel_engine, :to => :active_record
-
-          def initialize(active_record)
-            @active_record = active_record
-            @cached_record = {}
-            @column_names_with_alias = nil
-          end
-
-          def aliased_table
-            Arel::Nodes::TableAlias.new aliased_table_name, table
-          end
-
-          def ==(other)
-            raise NotImplementedError
-          end
-
-          # An Arel::Table for the active_record
-          def table
-            raise NotImplementedError
-          end
-
-          # The prefix to be used when aliasing columns in the active_record's table
-          def aliased_prefix
-            raise NotImplementedError
-          end
-
-          # The alias for the active_record's table
-          def aliased_table_name
-            raise NotImplementedError
-          end
-
-          # The alias for the primary key of the active_record's table
-          def aliased_primary_key
-            "#{aliased_prefix}_r0"
-          end
-
-          # An array of [column_name, alias] pairs for the table
-          def column_names_with_alias
-            unless @column_names_with_alias
-              @column_names_with_alias = []
-
-              ([primary_key] + (column_names - [primary_key])).each_with_index do |column_name, i|
-                @column_names_with_alias << [column_name, "#{aliased_prefix}_r#{i}"]
-              end
-            end
-            @column_names_with_alias
-          end
-
-          def extract_record(row)
-            Hash[column_names_with_alias.map{|cn, an| [cn, row[an]]}]
-          end
-
-          def record_id(row)
-            row[aliased_primary_key]
-          end
-
-          def instantiate(row)
-            @cached_record[record_id(row)] ||= active_record.send(:instantiate, extract_record(row))
-          end
-        end
-      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..f3761bd2c7
--- /dev/null
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -0,0 +1,549 @@
+require 'active_support/core_ext/array/wrap'
+
+module ActiveRecord
+  module Associations
+    # = Active Record Association Collection
+    #
+    # AssociationCollection is an abstract class that provides common stuff to
+    # ease the implementation of association proxies that represent
+    # collections. See the class hierarchy in AssociationProxy.
+    #
+    # 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:
+      attr_reader :proxy
+
+      def initialize(owner, reflection)
+        # When scopes are created via method_missing on the proxy, they are stored so that
+        # any records fetched from the database are kept around for future use.
+        @scopes_cache = Hash.new do |hash, method|
+          hash[method] = { }
+        end
+
+        super
+
+        @proxy = CollectionProxy.new(self)
+      end
+
+      # 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
+      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? || options[:finder_sql]
+          load_target.map do |record|
+            record.send(reflection.association_primary_key)
+          end
+        else
+          column  = "#{reflection.quoted_table_name}.#{reflection.association_primary_key}"
+
+          scoped.select(column).except(:includes).map! do |record|
+            record.send(reflection.association_primary_key)
+          end
+        end
+      end
+
+      # Implements the ids writer method, e.g. foo.item_ids= for Foo.has_many :items
+      def ids_writer(ids)
+        pk_column = reflection.primary_key_column
+        ids = Array.wrap(ids).reject { |id| id.blank? }
+        ids.map! { |i| pk_column.type_cast(i) }
+        replace(klass.find(ids).index_by { |r| r.id }.values_at(*ids))
+      end
+
+      def reset
+        @loaded = false
+        @target = []
+        @scopes_cache.clear
+      end
+
+      def select(select = nil)
+        if block_given?
+          load_target.select.each { |e| yield e }
+        else
+          scoped.select(select)
+        end
+      end
+
+      def find(*args)
+        if options[:finder_sql]
+          find_by_scan(*args)
+        else
+          scoped.find(*args)
+        end
+      end
+
+      def first(*args)
+        first_or_last(:first, *args)
+      end
+
+      def last(*args)
+        first_or_last(:last, *args)
+      end
+
+      def build(attributes = {}, &block)
+        build_or_create(attributes, :build, &block)
+      end
+
+      def create(attributes = {}, &block)
+        unless owner.persisted?
+          raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
+        end
+
+        build_or_create(attributes, :create, &block)
+      end
+
+      def create!(attrs = {}, &block)
+        record = create(attrs, &block)
+        Array.wrap(record).each(&:save!)
+        record
+      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)
+        result = true
+        load_target if owner.new_record?
+
+        transaction do
+          records.flatten.each do |record|
+            raise_on_type_mismatch(record)
+            add_to_target(record) do |r|
+              result &&= insert_record(record) unless owner.new_record?
+            end
+          end
+        end
+
+        result && records
+      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
+
+      # Remove all records from this association
+      #
+      # See delete for more info.
+      def delete_all
+        delete(load_target).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
+
+      # Calculate sum using SQL, not Enumerable
+      def sum(*args)
+        if block_given?
+          scoped.sum(*args) { |*block_args| yield(*block_args) }
+        else
+          scoped.sum(*args)
+        end
+      end
+
+      # Count all records using SQL. If the +:counter_sql+ or +:finder_sql+ option is set for the
+      # association, it will be used for the query. Otherwise, construct options and pass them with
+      # scope to the target class's +count+.
+      def count(column_name = nil, count_options = {})
+        column_name, count_options = nil, column_name if column_name.is_a?(Hash)
+
+        if options[:counter_sql] || options[:finder_sql]
+          unless count_options.blank?
+            raise ArgumentError, "If finder_sql/counter_sql is used then options cannot be passed"
+          end
+
+          reflection.klass.count_by_sql(custom_counter_sql)
+        else
+          if options[:uniq]
+            # This is needed because 'SELECT count(DISTINCT *)..' is not valid SQL.
+            column_name ||= reflection.klass.primary_key
+            count_options.merge!(:distinct => true)
+          end
+
+          value = scoped.count(column_name, count_options)
+
+          limit  = options[:limit]
+          offset = options[:offset]
+
+          if limit || offset
+            [ [value - offset.to_i, 0].max, limit.to_i ].min
+          else
+            value
+          end
+        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)
+        delete_or_destroy(records, options[:dependent])
+      end
+
+      # Destroy +records+ and remove them from this association calling
+      # +before_remove+ and +after_remove+ callbacks.
+      #
+      # Note that this method will _always_ remove records from the database
+      # ignoring the +:dependent+ option.
+      def destroy(*records)
+        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 owner.new_record? || (loaded? && !options[:uniq])
+          target.size
+        elsif !loaded? && options[:group]
+          load_target.size
+        elsif !loaded? && !options[:uniq] && 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
+
+      # Equivalent to <tt>collection.size.zero?</tt>. If the collection has
+      # not been already loaded and you are going to fetch the records anyway
+      # it is better to check <tt>collection.length.zero?</tt>.
+      def empty?
+        size.zero?
+      end
+
+      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 uniq(collection = load_target)
+        seen = {}
+        collection.find_all do |record|
+          seen[record.id] = true unless seen.key?(record.id)
+        end
+      end
+
+      # 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
+
+        transaction do
+          delete(target - other_array)
+
+          unless concat(other_array - target)
+            @target = original_target
+            raise RecordNotSaved, "Failed to replace #{reflection.name} because one or more of the " \
+                                  "new records could not be saved."
+          end
+        end
+      end
+
+      def include?(record)
+        if record.is_a?(reflection.klass)
+          if record.new_record?
+            include_in_memory?(record)
+          else
+            load_target if options[:finder_sql]
+            loaded? ? target.include?(record) : scoped.exists?(record)
+          end
+        else
+          false
+        end
+      end
+
+      def cached_scope(method, args)
+        @scopes_cache[method][args] ||= scoped.readonly(nil).send(method, *args)
+      end
+
+      def association_scope
+        options = reflection.options.slice(:order, :limit, :joins, :group, :having, :offset)
+        super.apply_finder_options(options)
+      end
+
+      def load_target
+        if find_target?
+          targets = []
+
+          begin
+            targets = find_target
+          rescue ActiveRecord::RecordNotFound
+            reset
+          end
+
+          @target = merge_target_lists(targets, target)
+        end
+
+        loaded!
+        target
+      end
+
+      def add_to_target(record)
+        transaction do
+          callback(:before_add, record)
+          yield(record) if block_given?
+
+          if options[:uniq] && index = @target.index(record)
+            @target[index] = record
+          else
+            @target << record
+          end
+
+          callback(:after_add, record)
+          set_inverse_instance(record)
+        end
+
+        record
+      end
+
+      private
+
+        def select_value
+          super || uniq_select_value
+        end
+
+        def uniq_select_value
+          options[:uniq] && "DISTINCT #{reflection.quoted_table_name}.*"
+        end
+
+        def custom_counter_sql
+          if options[:counter_sql]
+            interpolate(options[:counter_sql])
+          else
+            # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */
+            interpolate(options[:finder_sql]).sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" }
+          end
+        end
+
+        def custom_finder_sql
+          interpolate(options[:finder_sql])
+        end
+
+        def find_target
+          records =
+            if options[:finder_sql]
+              reflection.klass.find_by_sql(custom_finder_sql)
+            else
+              find(:all)
+            end
+
+          records = options[:uniq] ? uniq(records) : records
+          records.each { |record| set_inverse_instance(record) }
+          records
+        end
+
+        def merge_target_lists(loaded, existing)
+          return loaded if existing.empty?
+          return existing if loaded.empty?
+
+          loaded.map do |f|
+            i = existing.index(f)
+            if i
+              existing.delete_at(i).tap do |t|
+                keys = ["id"] + t.changes.keys + (f.attribute_names - t.attribute_names)
+                # FIXME: this call to attributes causes many NoMethodErrors
+                attributes = f.attributes
+                (attributes.keys - keys).each do |k|
+                  t.send("#{k}=", attributes[k])
+                end
+              end
+            else
+              f
+            end
+          end + existing
+        end
+
+        def build_or_create(attributes, method)
+          records = Array.wrap(attributes).map do |attrs|
+            record = build_record(attrs)
+
+            add_to_target(record) do
+              yield(record) if block_given?
+              insert_record(record) if method == :create
+            end
+          end
+
+          attributes.is_a?(Array) ? records : records.first
+        end
+
+        # Do the relevant stuff to insert the given record into the association collection.
+        def insert_record(record, validate = true)
+          raise NotImplementedError
+        end
+
+        def build_record(attributes)
+          reflection.build_association(scoped.scope_for_create.merge(attributes))
+        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? }
+
+          transaction do
+            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
+        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 callback(method, record)
+          callbacks_for(method).each do |callback|
+            case callback
+            when Symbol
+              owner.send(callback, record)
+            when Proc
+              callback.call(owner, record)
+            else
+              callback.send(method, owner, record)
+            end
+          end
+        end
+
+        def callbacks_for(callback_name)
+          full_callback_name = "#{callback_name}_for_#{reflection.name}"
+          owner.class.send(full_callback_name.to_sym) || []
+        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
+        #   * custom :finder_sql exists
+        #   * target contains new or changed record(s)
+        #   * the first arg is an integer (which indicates the number of records to be returned)
+        def fetch_first_or_last_using_find?(args)
+          if args.first.is_a?(Hash)
+            true
+          else
+            !(loaded? ||
+              owner.new_record? ||
+              options[:finder_sql] ||
+              target.any? { |record| record.new_record? || record.changed? } ||
+              args.first.kind_of?(Integer))
+          end
+        end
+
+        def include_in_memory?(record)
+          if reflection.is_a?(ActiveRecord::Reflection::ThroughReflection)
+            owner.send(reflection.through_reflection.name).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 using a custom finder_sql, #find scans the entire collection.
+        def find_by_scan(*args)
+          expects_array = args.first.kind_of?(Array)
+          ids           = args.flatten.compact.uniq.map { |arg| arg.to_i }
+
+          if ids.size == 1
+            id = ids.first
+            record = load_target.detect { |r| id == r.id }
+            expects_array ? [ record ] : record
+          else
+            load_target.select { |r| ids.include?(r.id) }
+          end
+        end
+
+        # Fetches the first/last using SQL if possible, otherwise from the target array.
+        def first_or_last(type, *args)
+          args.shift if args.first.is_a?(Hash) && args.first.empty?
+
+          collection = fetch_first_or_last_using_find?(args) ? scoped : load_target
+          collection.send(type, *args)
+        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..cf77d770c9
--- /dev/null
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -0,0 +1,127 @@
+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.find(: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 has most of the basic instance methods removed, and delegates
+    # unknown methods to <tt>@target</tt> via <tt>method_missing</tt>. As a
+    # corner case, it even removes the +class+ method and that's why you get
+    #
+    #   blog.posts.class # => Array
+    #
+    # though the object behind <tt>blog.posts</tt> is not an Array, but an
+    # ActiveRecord::Associations::HasManyAssociation.
+    #
+    # 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 # :nodoc:
+      alias :proxy_extend :extend
+
+      instance_methods.each { |m| undef_method m unless m.to_s =~ /^(?:nil\?|send|object_id|to_a)$|^__|^respond_to|proxy_/ }
+
+      delegate :group, :order, :limit, :joins, :where, :preload, :eager_load, :includes, :from,
+               :lock, :readonly, :having, :to => :scoped
+
+      delegate :target, :load_target, :loaded?, :scoped,
+               :to => :@association
+
+      delegate :select, :find, :first, :last,
+               :build, :create, :create!,
+               :concat, :delete_all, :destroy_all, :delete, :destroy, :uniq,
+               :sum, :count, :size, :length, :empty?,
+               :any?, :many?, :include?,
+               :to => :@association
+
+      def initialize(association)
+        @association = association
+        Array.wrap(association.options[:extend]).each { |ext| proxy_extend(ext) }
+      end
+
+      def respond_to?(*args)
+        super ||
+        (load_target && target.respond_to?(*args)) ||
+        @association.klass.respond_to?(*args)
+      end
+
+      def method_missing(method, *args, &block)
+        match = DynamicFinderMatch.match(method)
+        if match && match.creator?
+          attributes = match.attribute_names
+          return send(:"find_by_#{attributes.join('_and_')}", *args) || create(Hash[attributes.zip(args)])
+        end
+
+        if target.respond_to?(method) || (!@association.klass.respond_to?(method) && Class.respond_to?(method))
+          if load_target
+            if target.respond_to?(method)
+              target.send(method, *args, &block)
+            else
+              begin
+                super
+              rescue NoMethodError => e
+                raise e, e.message.sub(/ for #<.*$/, " via proxy for #{target}")
+              end
+            end
+          end
+
+        elsif @association.klass.scopes[method]
+          @association.cached_scope(method, args)
+        else
+          scoped.readonly(nil).send(method, *args, &block)
+        end
+      end
+
+      # Forwards <tt>===</tt> explicitly to the \target because the instance method
+      # removal above doesn't catch it. Loads the \target if needed.
+      def ===(other)
+        other === load_target
+      end
+
+      def to_ary
+        load_target.dup
+      end
+      alias_method :to_a, :to_ary
+
+      def <<(*records)
+        @association.concat(records) && self
+      end
+      alias_method :push, :<<
+
+      def clear
+        delete_all
+        self
+      end
+
+      def reload
+        @association.reload
+        self
+      end
+
+      def new(*args, &block)
+        if @association.is_a?(HasManyThroughAssociation)
+          @association.build(*args, &block)
+        else
+          method_missing(:new, *args, &block)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index e2ce9aefcf..028630977d 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -1,134 +1,73 @@
 module ActiveRecord
   # = Active Record Has And Belongs To Many Association
   module Associations
-    class HasAndBelongsToManyAssociation < AssociationCollection #:nodoc:
-      def create(attributes = {})
-        create_record(attributes) { |record| insert_record(record) }
-      end
+    class HasAndBelongsToManyAssociation < CollectionAssociation #:nodoc:
+      attr_reader :join_table
 
-      def create!(attributes = {})
-        create_record(attributes) { |record| insert_record(record, true) }
+      def initialize(owner, reflection)
+        @join_table = Arel::Table.new(reflection.options[:join_table])
+        super
       end
 
-      def columns
-        @reflection.columns(@reflection.options[:join_table], "#{@reflection.options[:join_table]} Columns")
-      end
+      def insert_record(record, validate = true)
+        return if record.new_record? && !record.save(:validate => validate)
+
+        if options[:insert_sql]
+          owner.connection.insert(interpolate(options[:insert_sql], record))
+        else
+          stmt = join_table.compile_insert(
+            join_table[reflection.foreign_key]             => owner.id,
+            join_table[reflection.association_foreign_key] => record.id
+          )
 
-      def reset_column_information
-        @reflection.reset_column_information
+          owner.connection.insert stmt.to_sql
+        end
+
+        record
       end
 
-      def has_primary_key?
-        @has_primary_key ||= @owner.connection.supports_primary_key? && @owner.connection.primary_key(@reflection.options[:join_table])
+      def association_scope
+        super.joins(construct_joins)
       end
 
-      protected
-        def construct_find_options!(options)
-          options[:joins]      = Arel::SqlLiteral.new(@scope[:find][:joins])
-          options[:readonly]   = finding_with_ambiguous_select?(options[:select] || @reflection.options[:select])
-          options[:select]   ||= (@reflection.options[:select] || Arel::SqlLiteral.new('*'))
-        end
+      private
 
         def count_records
           load_target.size
         end
 
-        def insert_record(record, force = true, validate = true)
-          if record.new_record?
-            if force
-              record.save!
-            else
-              return false unless record.save(:validate => validate)
-            end
-          end
-
-          if @reflection.options[:insert_sql]
-            @owner.connection.insert(interpolate_sql(@reflection.options[:insert_sql], record))
+        def delete_records(records, method)
+          if sql = options[:delete_sql]
+            records.each { |record| owner.connection.delete(interpolate(sql, record)) }
           else
-            relation   = Arel::Table.new(@reflection.options[:join_table])
-            timestamps = record_timestamp_columns(record)
-            timezone   = record.send(:current_time_from_proper_timezone) if timestamps.any?
-
-            attributes = columns.map do |column|
-              name = column.name
-              value = case name.to_s
-                when @reflection.primary_key_name.to_s
-                  @owner.id
-                when @reflection.association_foreign_key.to_s
-                  record.id
-                when *timestamps
-                  timezone
-                else
-                  @owner.send(:quote_value, record[name], column) if record.has_attribute?(name)
-              end
-              [relation[name], value] unless value.nil?
-            end
-
-            stmt = relation.compile_insert Hash[attributes]
-            @owner.connection.insert stmt.to_sql
-          end
-
-          true
-        end
-
-        def delete_records(records)
-          if sql = @reflection.options[:delete_sql]
-            records.each { |record| @owner.connection.delete(interpolate_sql(sql, record)) }
-          else
-            relation = Arel::Table.new(@reflection.options[:join_table])
-            stmt = relation.where(relation[@reflection.primary_key_name].eq(@owner.id).
-              and(relation[@reflection.association_foreign_key].in(records.map { |x| x.id }.compact))
+            relation = join_table
+            stmt = relation.where(relation[reflection.foreign_key].eq(owner.id).
+              and(relation[reflection.association_foreign_key].in(records.map { |x| x.id }.compact))
             ).compile_delete
-            @owner.connection.delete stmt.to_sql
+            owner.connection.delete stmt.to_sql
           end
         end
 
         def construct_joins
-          "INNER JOIN #{@owner.connection.quote_table_name @reflection.options[:join_table]} ON #{@reflection.quoted_table_name}.#{@reflection.klass.primary_key} = #{@owner.connection.quote_table_name @reflection.options[:join_table]}.#{@reflection.association_foreign_key}"
-        end
+          right = join_table
+          left  = reflection.klass.arel_table
 
-        def construct_conditions
-          sql = "#{@owner.connection.quote_table_name @reflection.options[:join_table]}.#{@reflection.primary_key_name} = #{owner_quoted_id} "
-          sql << " AND (#{conditions})" if conditions
-          sql
-        end
+          condition = left[reflection.klass.primary_key].eq(
+            right[reflection.association_foreign_key])
 
-        def construct_find_scope
-          {
-            :conditions => construct_conditions,
-            :joins      => construct_joins,
-            :readonly   => false,
-            :order      => @reflection.options[:order],
-            :include    => @reflection.options[:include],
-            :limit      => @reflection.options[:limit]
-          }
+          right.create_join(right, right.create_on(condition))
         end
 
-        # Join tables with additional columns on top of the two foreign keys must be considered
-        # ambiguous unless a select clause has been explicitly defined. Otherwise you can get
-        # broken records back, if, for example, the join column also has an id column. This will
-        # then overwrite the id column of the records coming back.
-        def finding_with_ambiguous_select?(select_clause)
-          !select_clause && columns.size != 2
+        def construct_owner_conditions
+          super(join_table)
         end
 
-      private
-        def create_record(attributes, &block)
-          # Can't use Base.create because the foreign key may be a protected attribute.
-          ensure_owner_is_persisted!
-          if attributes.is_a?(Array)
-            attributes.collect { |attr| create(attr) }
-          else
-            build_record(attributes, &block)
-          end
+        def select_value
+          super || reflection.klass.arel_table[Arel.star]
         end
 
-        def record_timestamp_columns(record)
-          if record.record_timestamps
-            record.send(:all_timestamp_attributes).map { |x| x.to_s }
-          else
-            []
-          end
+        def invertible_for?(record)
+          false
         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
index 851b10e300..cebf3e477a 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -5,15 +5,14 @@ module ActiveRecord
     #
     # If the association has a <tt>:through</tt> option further specialization
     # is provided by its child HasManyThroughAssociation.
-    class HasManyAssociation < AssociationCollection #:nodoc:
-      protected
-        def owner_quoted_id(reflection = @reflection)
-          if reflection.options[:primary_key]
-            @owner.class.quote_value(@owner.send(reflection.options[:primary_key]))
-          else
-            @owner.quoted_id
-          end
-        end
+    class HasManyAssociation < CollectionAssociation #:nodoc:
+
+      def insert_record(record, validate = true)
+        set_owner_attributes(record)
+        record.save(:validate => validate)
+      end
+
+      private
 
         # Returns the number of records in this collection.
         #
@@ -30,87 +29,73 @@ module ActiveRecord
         # the loaded flag is set to true as well.
         def count_records
           count = if has_cached_counter?
-            @owner.send(:read_attribute, cached_counter_attribute_name)
-          elsif @reflection.options[:counter_sql] || @reflection.options[:finder_sql]
-            @reflection.klass.count_by_sql(custom_counter_sql)
+            owner.send(:read_attribute, cached_counter_attribute_name)
+          elsif options[:counter_sql] || options[:finder_sql]
+            reflection.klass.count_by_sql(custom_counter_sql)
           else
-            @reflection.klass.count(@scope[:find].slice(:conditions, :joins, :include))
+            scoped.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
+          @target ||= [] and loaded! if count == 0
 
-          [@reflection.options[:limit], count].compact.min
+          [options[:limit], count].compact.min
         end
 
-        def has_cached_counter?
-          @owner.attribute_present?(cached_counter_attribute_name)
+        def has_cached_counter?(reflection = reflection)
+          owner.attribute_present?(cached_counter_attribute_name(reflection))
         end
 
-        def cached_counter_attribute_name
-          "#{@reflection.name}_count"
+        def cached_counter_attribute_name(reflection = reflection)
+          "#{reflection.name}_count"
         end
 
-        def insert_record(record, force = false, validate = true)
-          set_belongs_to_association_for(record)
-          force ? record.save! : record.save(:validate => validate)
-        end
-
-        # Deletes the records according to the <tt>:dependent</tt> option.
-        def delete_records(records)
-          case @reflection.options[:dependent]
-            when :destroy
-              records.each { |r| r.destroy }
-            when :delete_all
-              @reflection.klass.delete(records.map { |record| record.id })
-            else
-              relation = Arel::Table.new(@reflection.table_name)
-              stmt = relation.where(relation[@reflection.primary_key_name].eq(@owner.id).
-                  and(relation[@reflection.klass.primary_key].in(records.map { |r| r.id }))
-              ).compile_update(relation[@reflection.primary_key_name] => nil)
-              @owner.connection.update stmt.to_sql
-
-              @owner.class.update_counters(@owner.id, cached_counter_attribute_name => -records.size) if has_cached_counter?
+        def update_counter(difference, reflection = reflection)
+          if has_cached_counter?(reflection)
+            counter = cached_counter_attribute_name(reflection)
+            owner.class.update_counters(owner.id, counter => difference)
+            owner[counter] += difference
+            owner.changed_attributes.delete(counter) # eww
           end
         end
 
-        def target_obsolete?
-          false
+        # 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)
+          reflection.klass.reflect_on_all_associations(:belongs_to).any? { |inverse_reflection|
+            inverse_reflection.counter_cache_column == counter_name
+          }
         end
 
-        def construct_conditions
-          if @reflection.options[:as]
-            sql =
-              "#{@reflection.quoted_table_name}.#{@reflection.options[:as]}_id = #{owner_quoted_id} AND " +
-              "#{@reflection.quoted_table_name}.#{@reflection.options[:as]}_type = #{@owner.class.quote_value(@owner.class.base_class.name.to_s)}"
+        # Deletes the records according to the <tt>:dependent</tt> option.
+        def delete_records(records, method)
+          if method == :destroy
+            records.each { |r| r.destroy }
+            update_counter(-records.length) unless inverse_updates_counter_cache?
           else
-            sql = "#{@reflection.quoted_table_name}.#{@reflection.primary_key_name} = #{owner_quoted_id}"
-          end
-          sql << " AND (#{conditions})" if conditions
-          sql
-        end
+            keys  = records.map { |r| r[reflection.association_primary_key] }
+            scope = scoped.where(reflection.association_primary_key => keys)
 
-        def construct_find_scope
-          {
-            :conditions => construct_conditions,
-            :readonly   => false,
-            :order      => @reflection.options[:order],
-            :limit      => @reflection.options[:limit],
-            :include    => @reflection.options[:include]
-          }
-        end
-
-        def construct_create_scope
-          create_scoping = {}
-          set_belongs_to_association_for(create_scoping)
-          create_scoping
+            if method == :delete_all
+              update_counter(-scope.delete_all)
+            else
+              update_counter(-scope.update_all(reflection.foreign_key => nil))
+            end
+          end
         end
 
-        def we_can_set_the_inverse_on_this?(record)
-          @reflection.inverse_of
-        end
+        alias creation_attributes construct_owner_attributes
     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
index 0b00132ad9..9d2b29685b 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -1,109 +1,144 @@
-require "active_record/associations/through_association_scope"
 require 'active_support/core_ext/object/blank'
 
 module ActiveRecord
   # = Active Record Has Many Through Association
   module Associations
     class HasManyThroughAssociation < HasManyAssociation #:nodoc:
-      include ThroughAssociationScope
-
-      def build(attributes = {}, &block)
-        ensure_not_nested
-        super
-      end
+      include ThroughAssociation
 
       alias_method :new, :build
 
-      def create!(attrs = nil)
-        create_record(attrs, true)
-      end
-
-      def create(attrs = nil)
-        create_record(attrs, false)
-      end
-
-      def destroy(*records)
-        transaction do
-          delete_records(flatten_deeper(records))
-          super
-        end
-      end
-
       # Returns the size of the collection by executing a SELECT COUNT(*) query if the collection hasn't been
       # loaded and calling collection.size if it has. If it's more likely than not that the collection does
       # have a size larger than zero, and you need to fetch that collection afterwards, it'll take one fewer
       # SELECT query if you use #length.
       def size
-        return @owner.send(:read_attribute, cached_counter_attribute_name) if has_cached_counter?
-        return @target.size if loaded?
-        return count
+        if has_cached_counter?
+          owner.send(:read_attribute, cached_counter_attribute_name)
+        elsif loaded?
+          target.size
+        else
+          count
+        end
+      end
+
+      def concat(*records)
+        unless owner.new_record?
+          records.flatten.each do |record|
+            raise_on_type_mismatch(record)
+            record.save! if record.new_record?
+          end
+        end
+
+        super
       end
 
-      protected
-        def create_record(attrs, force = true)
+      def insert_record(record, validate = true)
+        ensure_not_nested
+        return if record.new_record? && !record.save(:validate => validate)
+
+        through_record(record).save!
+        update_counter(1)
+        record
+      end
+
+      private
+
+        def through_record(record)
+          through_association = owner.association(through_reflection.name)
+          attributes = construct_join_attributes(record)
+
+          through_record = Array.wrap(through_association.target).find { |candidate|
+            candidate.attributes.slice(*attributes.keys) == attributes
+          }
+
+          unless through_record
+            through_record = through_association.build(attributes)
+            through_record.send("#{source_reflection.name}=", record)
+          end
+
+          through_record
+        end
+
+        def build_record(attributes)
           ensure_not_nested
-          ensure_owner_is_persisted!
 
-          transaction do
-            object = @reflection.klass.new(attrs)
-            add_record_to_target_with_callbacks(object) {|r| insert_record(object, force) }
-            object
+          record = super(attributes)
+
+          inverse = source_reflection.inverse_of
+          if inverse
+            if inverse.macro == :has_many
+              record.send(inverse.name) << through_record(record)
+            elsif inverse.macro == :has_one
+              record.send("#{inverse.name}=", through_record(record))
+            end
           end
+
+          record
         end
 
         def target_reflection_has_associated_record?
-          if @reflection.through_reflection.macro == :belongs_to && @owner[@reflection.through_reflection.primary_key_name].blank?
+          if through_reflection.macro == :belongs_to && owner[through_reflection.foreign_key].blank?
             false
           else
             true
           end
         end
 
-        def construct_find_options!(options)
-          options[:joins]   = construct_joins(options[:joins])
-          options[:include] = @reflection.source_reflection.options[:include] if options[:include].nil? && @reflection.source_reflection.options[:include]
+        def update_through_counter?(method)
+          case method
+          when :destroy
+            !inverse_updates_counter_cache?(through_reflection)
+          when :nullify
+            false
+          else
+            true
+          end
         end
 
-        def insert_record(record, force = true, validate = true)
+        def delete_records(records, method)
           ensure_not_nested
 
-          if record.new_record?
-            if force
-              record.save!
-            else
-              return false unless record.save(:validate => validate)
-            end
-          end
+          through = owner.association(through_reflection.name)
+          scope   = through.scoped.where(construct_join_attributes(*records))
 
-          through_association = @owner.send(@reflection.through_reflection.name)
-          through_association.create!(construct_join_attributes(record))
-        end
+          case method
+          when :destroy
+            count = scope.destroy_all.length
+          when :nullify
+            count = scope.update_all(source_reflection.foreign_key => nil)
+          else
+            count = scope.delete_all
+          end
 
-        # TODO - add dependent option support
-        def delete_records(records)
-          ensure_not_nested
+          delete_through_records(through, records)
 
-          klass = @reflection.through_reflection.klass
-          records.each do |associate|
-            klass.delete_all(construct_join_attributes(associate))
+          if through_reflection.macro == :has_many && update_through_counter?(method)
+            update_counter(-count, through_reflection)
           end
-        end
 
-        def find_target
-          return [] unless target_reflection_has_associated_record?
-          with_scope(@scope) { @reflection.klass.find(:all) }
+          update_counter(-count)
         end
 
-        def has_cached_counter?
-          @owner.attribute_present?(cached_counter_attribute_name)
+        def delete_through_records(through, records)
+          if through_reflection.macro == :has_many
+            records.each do |record|
+              through.target.delete(through_record(record))
+            end
+          else
+            records.each do |record|
+              through.target = nil if through.target == through_record(record)
+            end
+          end
         end
 
-        def cached_counter_attribute_name
-          "#{@reflection.name}_count"
+        def find_target
+          return [] unless target_reflection_has_associated_record?
+          scoped.all
         end
 
         # NOTE - not sure that we can actually cope with inverses here
-        def we_can_set_the_inverse_on_this?(record)
+        def invertible_for?(record)
           false
         end
     end
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
index d581939f04..e13f97125f 100644
--- a/activerecord/lib/active_record/associations/has_one_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -1,135 +1,76 @@
 module ActiveRecord
   # = Active Record Belongs To Has One Association
   module Associations
-    class HasOneAssociation < AssociationProxy #:nodoc:
-      def create(attrs = {}, replace_existing = true)
-        new_record(replace_existing) do |reflection|
-          attrs = merge_with_conditions(attrs)
-          reflection.create_association(attrs)
-        end
-      end
+    class HasOneAssociation < SingularAssociation #:nodoc:
+      def replace(record, save = true)
+        raise_on_type_mismatch(record) if record
+        load_target
 
-      def create!(attrs = {}, replace_existing = true)
-        new_record(replace_existing) do |reflection|
-          attrs = merge_with_conditions(attrs)
-          reflection.create_association!(attrs)
-        end
-      end
+        reflection.klass.transaction do
+          if target && target != record
+            remove_target!(options[:dependent])
+          end
+
+          if record
+            set_inverse_instance(record)
+            set_owner_attributes(record)
 
-      def build(attrs = {}, replace_existing = true)
-        new_record(replace_existing) do |reflection|
-          attrs = merge_with_conditions(attrs)
-          reflection.build_association(attrs)
+            if owner.persisted? && save && !record.save
+              nullify_owner_attributes(record)
+              set_owner_attributes(target)
+              raise RecordNotSaved, "Failed to save the new associated #{reflection.name}."
+            end
+          end
         end
-      end
 
-      def replace(obj, dont_save = false)
-        load_target
+        self.target = record
+      end
 
-        unless @target.nil? || @target == obj
-          if dependent? && !dont_save
-            case @reflection.options[:dependent]
+      def delete(method = options[:dependent])
+        if load_target
+          case method
             when :delete
-              @target.delete if @target.persisted?
-              @owner.clear_association_cache
+              target.delete
             when :destroy
-              @target.destroy if @target.persisted?
-              @owner.clear_association_cache
+              target.destroy
             when :nullify
-              @target[@reflection.primary_key_name] = nil
-              @target.save if @owner.persisted? && @target.persisted?
-            end
-          else
-            @target[@reflection.primary_key_name] = nil
-            @target.save if @owner.persisted? && @target.persisted?
+              target.update_attribute(reflection.foreign_key, nil)
           end
         end
-
-        if obj.nil?
-          @target = nil
-        else
-          raise_on_type_mismatch(obj)
-          set_belongs_to_association_for(obj)
-          @target = (AssociationProxy === obj ? obj.target : obj)
-        end
-
-        set_inverse_instance(obj, @owner)
-        @loaded = true
-
-        unless !@owner.persisted? || obj.nil? || dont_save
-          return (obj.save ? self : false)
-        else
-          return (obj.nil? ? nil : self)
-        end
       end
 
-      protected
-        def owner_quoted_id(reflection = @reflection)
-          if reflection.options[:primary_key]
-            @owner.class.quote_value(@owner.send(reflection.options[:primary_key]))
-          else
-            @owner.quoted_id
-          end
-        end
+      def association_scope
+        super.order(options[:order])
+      end
 
       private
-        def find_target
-          options = @reflection.options.dup.slice(:select, :order, :include, :readonly)
 
-          the_target = with_scope(:find => @scope[:find]) do
-            @reflection.klass.find(:first, options)
-          end
-          set_inverse_instance(the_target, @owner)
-          the_target
-        end
-
-        def construct_find_scope
-          if @reflection.options[:as]
-            sql =
-              "#{@reflection.quoted_table_name}.#{@reflection.options[:as]}_id = #{owner_quoted_id} AND " +
-              "#{@reflection.quoted_table_name}.#{@reflection.options[:as]}_type = #{@owner.class.quote_value(@owner.class.base_class.name.to_s)}"
-          else
-            sql = "#{@reflection.quoted_table_name}.#{@reflection.primary_key_name} = #{owner_quoted_id}"
-          end
-          sql << " AND (#{conditions})" if conditions
-          { :conditions => sql }
-        end
+        alias creation_attributes construct_owner_attributes
 
-        def construct_create_scope
-          create_scoping = {}
-          set_belongs_to_association_for(create_scoping)
-          create_scoping
+        # 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 new_record(replace_existing)
-          # Make sure we load the target first, if we plan on replacing the existing
-          # instance. Otherwise, if the target has not previously been loaded
-          # elsewhere, the instance we create will get orphaned.
-          load_target if replace_existing
-          record = @reflection.klass.send(:with_scope, :create => @scope[:create]) do
-            yield @reflection
-          end
-
-          if replace_existing
-            replace(record, true)
+        def remove_target!(method)
+          if [:delete, :destroy].include?(method)
+            target.send(method)
           else
-            record[@reflection.primary_key_name] = @owner.id if @owner.persisted?
-            self.target = record
-            set_inverse_instance(record, @owner)
-          end
+            nullify_owner_attributes(target)
 
-          record
-        end
-
-        def we_can_set_the_inverse_on_this?(record)
-          inverse = @reflection.inverse_of
-          return !inverse.nil?
+            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 when after its foreign key was set to nil."
+            end
+          end
         end
 
-        def merge_with_conditions(attrs={})
-          attrs ||= {}
-          attrs.update(@reflection.options[:conditions]) if @reflection.options[:conditions].is_a?(Hash)
-          attrs
+        def nullify_owner_attributes(record)
+          record[reflection.foreign_key] = nil
         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
index e9dc32efd3..fdf8ae1453 100644
--- a/activerecord/lib/active_record/associations/has_one_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_through_association.rb
@@ -1,42 +1,36 @@
-require "active_record/associations/through_association_scope"
-
 module ActiveRecord
   # = Active Record Has One Through Association
   module Associations
-    class HasOneThroughAssociation < HasOneAssociation
-      include ThroughAssociationScope
+    class HasOneThroughAssociation < HasOneAssociation #:nodoc:
+      include ThroughAssociation
 
-      def replace(new_value)
-        create_through_record(new_value)
-        @target = new_value
+      def replace(record)
+        create_through_record(record)
+        self.target = record
       end
 
       private
 
-      def create_through_record(new_value) #nodoc:
-        ensure_not_nested
+        def create_through_record(record)
+          ensure_not_nested
 
-        klass = @reflection.through_reflection.klass
+          through_proxy  = owner.association(through_reflection.name)
+          through_record = through_proxy.send(:load_target)
 
-        current_object = @owner.send(@reflection.through_reflection.name)
+          if through_record && !record
+            through_record.destroy
+          elsif record
+            attributes = construct_join_attributes(record)
 
-        if current_object
-           new_value ? current_object.update_attributes(construct_join_attributes(new_value)) : current_object.destroy
-        elsif new_value
-          if @owner.new_record?
-            self.target = new_value
-            through_association = @owner.send(:association_instance_get, @reflection.through_reflection.name)
-            through_association.build(construct_join_attributes(new_value))
-          else
-            @owner.send(@reflection.through_reflection.name, klass.create(construct_join_attributes(new_value)))
+            if through_record
+              through_record.update_attributes(attributes)
+            elsif owner.new_record?
+              through_proxy.build(attributes)
+            else
+              through_proxy.create(attributes)
+            end
           end
         end
-      end
-
-    private
-      def find_target
-        with_scope(@scope) { @reflection.klass.find(:first) }
-      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..504f25271c
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -0,0 +1,215 @@
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      autoload :JoinPart,        'active_record/associations/join_dependency/join_part'
+      autoload :JoinBase,        'active_record/associations/join_dependency/join_base'
+      autoload :JoinAssociation, 'active_record/associations/join_dependency/join_association'
+
+      attr_reader :join_parts, :reflections, :alias_tracker, :active_record
+
+      def initialize(base, associations, joins)
+        @active_record = base
+        @table_joins   = joins
+        @join_parts    = [JoinBase.new(base)]
+        @associations  = {}
+        @reflections   = []
+        @alias_tracker = AliasTracker.new(joins)
+        @alias_tracker.aliased_name_for(base.table_name) # Updates the count for base.table_name to 1
+        build(associations)
+      end
+
+      def graft(*associations)
+        associations.each do |association|
+          join_associations.detect {|a| association == a} ||
+            build(association.reflection.name, association.find_parent_in(self) || join_base, association.join_type)
+        end
+        self
+      end
+
+      def join_associations
+        join_parts.last(join_parts.length - 1)
+      end
+
+      def join_base
+        join_parts.first
+      end
+
+      def columns
+        join_parts.collect { |join_part|
+          table = join_part.aliased_table
+          join_part.column_names_with_alias.collect{ |column_name, aliased_name|
+            table[column_name].as Arel.sql(aliased_name)
+          }
+        }.flatten
+      end
+
+      def instantiate(rows)
+        primary_key = join_base.aliased_primary_key
+        parents = {}
+
+        records = rows.map { |model|
+          primary_id = model[primary_key]
+          parent = parents[primary_id] ||= join_base.instantiate(model)
+          construct(parent, @associations, join_associations, model)
+          parent
+        }.uniq
+
+        remove_duplicate_results!(active_record, records, @associations)
+        records
+      end
+
+      def remove_duplicate_results!(base, records, associations)
+        case associations
+        when Symbol, String
+          reflection = base.reflections[associations]
+          remove_uniq_by_reflection(reflection, records)
+        when Array
+          associations.each do |association|
+            remove_duplicate_results!(base, records, association)
+          end
+        when Hash
+          associations.keys.each do |name|
+            reflection = base.reflections[name]
+            remove_uniq_by_reflection(reflection, records)
+
+            parent_records = []
+            records.each do |record|
+              if descendant = record.send(reflection.name)
+                if reflection.collection?
+                  parent_records.concat descendant.target.uniq
+                else
+                  parent_records << descendant
+                end
+              end
+            end
+
+            remove_duplicate_results!(reflection.klass, parent_records, associations[name]) unless parent_records.empty?
+          end
+        end
+      end
+
+      protected
+
+      def cache_joined_association(association)
+        associations = []
+        parent = association.parent
+        while parent != join_base
+          associations.unshift(parent.reflection.name)
+          parent = parent.parent
+        end
+        ref = @associations
+        associations.each do |key|
+          ref = ref[key]
+        end
+        ref[association.reflection.name] ||= {}
+      end
+
+      def build(associations, parent = nil, join_type = Arel::InnerJoin)
+        parent ||= join_parts.last
+        case associations
+        when Symbol, String
+          reflection = parent.reflections[associations.to_s.intern] or
+          raise ConfigurationError, "Association named '#{ associations }' was not found; perhaps you misspelled it?"
+          unless join_association = find_join_association(reflection, parent)
+            @reflections << reflection
+            join_association = build_join_association(reflection, parent)
+            join_association.join_type = join_type
+            @join_parts << join_association
+            cache_joined_association(join_association)
+          end
+          join_association
+        when Array
+          associations.each do |association|
+            build(association, parent, join_type)
+          end
+        when Hash
+          associations.keys.sort_by { |a| a.to_s }.each do |name|
+            join_association = build(name, parent, join_type)
+            build(associations[name], join_association, join_type)
+          end
+        else
+          raise ConfigurationError, associations.inspect
+        end
+      end
+
+      def find_join_association(name_or_reflection, parent)
+        if String === name_or_reflection
+          name_or_reflection = name_or_reflection.to_sym
+        end
+
+        join_associations.detect { |j|
+          j.reflection == name_or_reflection && j.parent == parent
+        }
+      end
+
+      def remove_uniq_by_reflection(reflection, records)
+        if reflection && reflection.collection?
+          records.each { |record| record.send(reflection.name).target.uniq! }
+        end
+      end
+
+      def build_join_association(reflection, parent)
+        JoinAssociation.new(reflection, self, parent)
+      end
+
+      def construct(parent, associations, join_parts, row)
+        case associations
+        when Symbol, String
+          name = associations.to_s
+
+          join_part = join_parts.detect { |j|
+            j.reflection.name.to_s == name &&
+              j.parent_table_name == parent.class.table_name }
+
+            raise(ConfigurationError, "No such association") unless join_part
+
+            join_parts.delete(join_part)
+            construct_association(parent, join_part, row)
+        when Array
+          associations.each do |association|
+            construct(parent, association, join_parts, row)
+          end
+        when Hash
+          associations.sort_by { |k,_| k.to_s }.each do |association_name, assoc|
+            association = construct(parent, association_name, join_parts, row)
+            construct(association, assoc, join_parts, row) if association
+          end
+        else
+          raise ConfigurationError, associations.inspect
+        end
+      end
+
+      def construct_association(record, join_part, row)
+        return if record.id.to_s != join_part.parent.record_id(row).to_s
+
+        macro = join_part.reflection.macro
+        if macro == :has_one
+          return if record.association_cache.key?(join_part.reflection.name)
+          association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil?
+          set_target_and_inverse(join_part, association, record)
+        else
+          return if row[join_part.aliased_primary_key].nil?
+          association = join_part.instantiate(row)
+          case macro
+          when :has_many, :has_and_belongs_to_many
+            other = record.association(join_part.reflection.name)
+            other.loaded!
+            other.target.push(association)
+            other.set_inverse_instance(association)
+          when :belongs_to
+            set_target_and_inverse(join_part, association, record)
+          else
+            raise ConfigurationError, "unknown macro: #{join_part.reflection.macro}"
+          end
+        end
+        association
+      end
+
+      def set_target_and_inverse(join_part, association, record)
+        other = record.association(join_part.reflection.name)
+        other.target = association
+        other.set_inverse_instance(association)
+      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..890e77fca9
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
@@ -0,0 +1,259 @@
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      class JoinAssociation < JoinPart # :nodoc:
+        # The reflection of the association represented
+        attr_reader :reflection
+
+        # The JoinDependency object which this JoinAssociation exists within. This is mainly
+        # relevant for generating aliases which do not conflict with other joins which are
+        # part of the query.
+        attr_reader :join_dependency
+
+        # A JoinBase instance representing the active record we are joining onto.
+        # (So in Author.has_many :posts, the Author would be that base record.)
+        attr_reader :parent
+
+        # What type of join will be generated, either Arel::InnerJoin (default) or Arel::OuterJoin
+        attr_accessor :join_type
+
+        # These implement abstract methods from the superclass
+        attr_reader :aliased_prefix
+
+        attr_reader :tables
+
+        delegate :options, :through_reflection, :source_reflection, :through_reflection_chain, :to => :reflection
+        delegate :table, :table_name, :to => :parent, :prefix => :parent
+        delegate :alias_tracker, :to => :join_dependency
+
+        def initialize(reflection, join_dependency, parent = nil)
+          reflection.check_validity!
+
+          if reflection.options[:polymorphic]
+            raise EagerLoadPolymorphicError.new(reflection)
+          end
+
+          super(reflection.klass)
+
+          @reflection      = reflection
+          @join_dependency = join_dependency
+          @parent          = parent
+          @join_type       = Arel::InnerJoin
+          @aliased_prefix  = "t#{ join_dependency.join_parts.size }"
+
+          setup_tables
+        end
+
+        def ==(other)
+          other.class == self.class &&
+            other.reflection == reflection &&
+            other.parent == parent
+        end
+
+        def find_parent_in(other_join_dependency)
+          other_join_dependency.join_parts.detect do |join_part|
+            parent == join_part
+          end
+        end
+
+        def join_to(relation)
+          # The chain starts with the target table, but we want to end with it here (makes
+          # more sense in this context)
+          chain = through_reflection_chain.reverse
+
+          foreign_table = parent_table
+          index = 0
+
+          chain.each do |reflection|
+            table = tables[index]
+            conditions = []
+
+            if reflection.source_reflection.nil?
+              case reflection.macro
+                when :belongs_to
+                  key         = reflection.association_primary_key
+                  foreign_key = reflection.foreign_key
+                when :has_many, :has_one
+                  key         = reflection.foreign_key
+                  foreign_key = reflection.active_record_primary_key
+
+                  conditions << polymorphic_conditions(reflection, table)
+                when :has_and_belongs_to_many
+                  # For habtm, we need to deal with the join table at the same time as the
+                  # target table (because unlike a :through association, there is no reflection
+                  # to represent the join table)
+                  table, join_table = table
+
+                  join_key         = reflection.foreign_key
+                  join_foreign_key = reflection.active_record.primary_key
+
+                  relation = relation.join(join_table, join_type).on(
+                    join_table[join_key].
+                      eq(foreign_table[join_foreign_key])
+                  )
+
+                  # We've done the first join now, so update the foreign_table for the second
+                  foreign_table = join_table
+
+                  key         = reflection.klass.primary_key
+                  foreign_key = reflection.association_foreign_key
+              end
+            else
+              case reflection.source_reflection.macro
+                when :belongs_to
+                  key         = reflection.association_primary_key
+                  foreign_key = reflection.foreign_key
+
+                  conditions << source_type_conditions(reflection, foreign_table)
+                when :has_many, :has_one
+                  key         = reflection.foreign_key
+                  foreign_key = reflection.source_reflection.active_record_primary_key
+                when :has_and_belongs_to_many
+                  table, join_table = table
+
+                  join_key         = reflection.foreign_key
+                  join_foreign_key = reflection.klass.primary_key
+
+                  relation = relation.join(join_table, join_type).on(
+                    join_table[join_key].
+                      eq(foreign_table[join_foreign_key])
+                  )
+
+                  foreign_table = join_table
+
+                  key         = reflection.klass.primary_key
+                  foreign_key = reflection.association_foreign_key
+              end
+            end
+
+            conditions << table[key].eq(foreign_table[foreign_key])
+
+            conditions << reflection_conditions(index, table)
+            conditions << sti_conditions(reflection, table)
+
+            ands = relation.create_and(conditions.flatten.compact)
+
+            join = relation.create_join(
+              table,
+              relation.create_on(ands),
+              join_type)
+
+            relation = relation.from(join)
+
+            # The current table in this iteration becomes the foreign table in the next
+            foreign_table = table
+            index += 1
+          end
+
+          relation
+        end
+
+        def join_relation(joining_relation)
+          self.join_type = Arel::OuterJoin
+          joining_relation.joins(self)
+        end
+
+        def table
+          if tables.last.is_a?(Array)
+            tables.last.first
+          else
+            tables.last
+          end
+        end
+
+        def aliased_table_name
+          table.table_alias || table.name
+        end
+
+        protected
+
+        def table_alias_for(reflection, join = false)
+          name = alias_tracker.pluralize(reflection.name)
+          name << "_#{parent_table_name}"
+          name << "_join" if join
+          name
+        end
+
+        private
+
+        # Generate aliases and Arel::Table instances for each of the tables which we will
+        # later generate joins for. We must do this in advance in order to correctly allocate
+        # the proper alias.
+        def setup_tables
+          @tables = through_reflection_chain.map do |reflection|
+            table = alias_tracker.aliased_table_for(
+              reflection.table_name,
+              table_alias_for(reflection, reflection != self.reflection)
+            )
+
+            # For habtm, we have two Arel::Table instances related to a single reflection, so
+            # we just store them as a pair in the array.
+            if reflection.macro == :has_and_belongs_to_many ||
+                 (reflection.source_reflection && reflection.source_reflection.macro == :has_and_belongs_to_many)
+
+              join_table = alias_tracker.aliased_table_for(
+                (reflection.source_reflection || reflection).options[:join_table],
+                table_alias_for(reflection, true)
+              )
+
+              [table, join_table]
+            else
+              table
+            end
+          end
+
+          # The joins are generated from the through_reflection_chain in reverse order, so
+          # reverse the tables too (but it's important to generate the aliases in the 'forward'
+          # order, which is why we only do the reversal now.
+          @tables.reverse!
+        end
+
+        def process_conditions(conditions, table_name)
+          if conditions.respond_to?(:to_proc)
+            conditions = instance_eval(&conditions)
+          end
+
+          Arel.sql(sanitize_sql(conditions, table_name))
+        end
+
+        def sanitize_sql(condition, table_name)
+          active_record.send(:sanitize_sql, condition, table_name)
+        end
+
+        def reflection_conditions(index, table)
+          reflection.through_conditions.reverse[index].map do |condition|
+            process_conditions(condition, table.table_alias || table.name)
+          end
+        end
+
+        def sti_conditions(reflection, table)
+          unless reflection.klass.descends_from_active_record?
+            sti_column    = table[reflection.klass.inheritance_column]
+            sti_condition = sti_column.eq(reflection.klass.sti_name)
+            subclasses    = reflection.klass.descendants
+
+            # TODO: use IN (...), or possibly AR::Base#type_condition
+            subclasses.inject(sti_condition) { |attr,subclass|
+              attr.or(sti_column.eq(subclass.sti_name))
+            }
+          end
+        end
+
+        def source_type_conditions(reflection, foreign_table)
+          if reflection.options[:source_type]
+            foreign_table[reflection.source_reflection.foreign_type].
+              eq(reflection.options[:source_type])
+          end
+        end
+
+        def polymorphic_conditions(reflection, table)
+          if reflection.options[:as]
+            table[reflection.type].
+              eq(reflection.active_record.base_class.name)
+          end
+        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..3920e84976
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
@@ -0,0 +1,24 @@
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      class JoinBase < JoinPart # :nodoc:
+        def ==(other)
+          other.class == self.class &&
+            other.active_record == active_record
+        end
+
+        def aliased_prefix
+          "t0"
+        end
+
+        def table
+          Arel::Table.new(table_name, arel_engine)
+        end
+
+        def aliased_table_name
+          active_record.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..3279e56e7d
--- /dev/null
+++ b/activerecord/lib/active_record/associations/join_dependency/join_part.rb
@@ -0,0 +1,78 @@
+module ActiveRecord
+  module Associations
+    class JoinDependency # :nodoc:
+      # A JoinPart represents a part of a JoinDependency. It is an abstract class, 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:
+        # 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 :active_record
+
+        delegate :table_name, :column_names, :primary_key, :reflections, :arel_engine, :to => :active_record
+
+        def initialize(active_record)
+          @active_record = active_record
+          @cached_record = {}
+          @column_names_with_alias = nil
+        end
+
+        def aliased_table
+          Arel::Nodes::TableAlias.new aliased_table_name, table
+        end
+
+        def ==(other)
+          raise NotImplementedError
+        end
+
+        # An Arel::Table for the active_record
+        def table
+          raise NotImplementedError
+        end
+
+        # The prefix to be used when aliasing columns in the active_record's table
+        def aliased_prefix
+          raise NotImplementedError
+        end
+
+        # The alias for the active_record's table
+        def aliased_table_name
+          raise NotImplementedError
+        end
+
+        # The alias for the primary key of the active_record's table
+        def aliased_primary_key
+          "#{aliased_prefix}_r0"
+        end
+
+        # An array of [column_name, alias] pairs for the table
+        def column_names_with_alias
+          unless @column_names_with_alias
+            @column_names_with_alias = []
+
+            ([primary_key] + (column_names - [primary_key])).each_with_index do |column_name, i|
+              @column_names_with_alias << [column_name, "#{aliased_prefix}_r#{i}"]
+            end
+          end
+          @column_names_with_alias
+        end
+
+        def extract_record(row)
+          Hash[column_names_with_alias.map{|cn, an| [cn, row[an]]}]
+        end
+
+        def record_id(row)
+          row[aliased_primary_key]
+        end
+
+        def instantiate(row)
+          @cached_record[record_id(row)] ||= active_record.send(:instantiate, extract_record(row))
+        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..fafed94ff2
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader.rb
@@ -0,0 +1,177 @@
+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.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:
+      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 :HasAndBelongsToMany, 'active_record/associations/preloader/has_and_belongs_to_many'
+      autoload :BelongsTo,           'active_record/associations/preloader/belongs_to'
+
+      attr_reader :records, :associations, :options, :model
+
+      # 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 } ]
+      #
+      # +options+ contains options that will be passed to ActiveRecord::Base#find
+      # (which is called under the hood for preloading records). But it is passed
+      # only one level deep in the +associations+ argument, i.e. it's not passed
+      # to the child associations when +associations+ is a Hash.
+      def initialize(records, associations, options = {})
+        @records      = Array.wrap(records).compact.uniq
+        @associations = Array.wrap(associations)
+        @options      = options
+      end
+
+      def run
+        unless records.empty?
+          associations.each { |association| preload(association) }
+        end
+      end
+
+      private
+
+      def preload(association)
+        case association
+        when Hash
+          preload_hash(association)
+        when String, Symbol
+          preload_one(association.to_sym)
+        else
+          raise ArgumentError, "#{association.inspect} was not recognised for preload"
+        end
+      end
+
+      def preload_hash(association)
+        association.each do |parent, child|
+          Preloader.new(records, parent, options).run
+          Preloader.new(records.map { |record| record.send(parent) }.flatten, child).run
+        end
+      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 preload_one(association)
+        grouped_records(association).each do |reflection, klasses|
+          klasses.each do |klass, records|
+            preloader_for(reflection).new(klass, records, reflection, options).run
+          end
+        end
+      end
+
+      def grouped_records(association)
+        Hash[
+          records_by_reflection(association).map do |reflection, records|
+            [reflection, records.group_by { |record| association_klass(reflection, record) }]
+          end
+        ]
+      end
+
+      def records_by_reflection(association)
+        records.group_by do |record|
+          reflection = record.class.reflections[association]
+
+          unless reflection
+            raise ActiveRecord::ConfigurationError, "Association named '#{association}' was not found; " \
+                                                    "perhaps you misspelled it?"
+          end
+
+          reflection
+        end
+      end
+
+      def association_klass(reflection, record)
+        if reflection.macro == :belongs_to && reflection.options[:polymorphic]
+          klass = record.send(reflection.foreign_type)
+          klass && klass.constantize
+        else
+          reflection.klass
+        end
+      end
+
+      def preloader_for(reflection)
+        case reflection.macro
+        when :has_many
+          reflection.options[:through] ? HasManyThrough : HasMany
+        when :has_one
+          reflection.options[:through] ? HasOneThrough : HasOne
+        when :has_and_belongs_to_many
+          HasAndBelongsToMany
+        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..7256dd5288
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/association.rb
@@ -0,0 +1,126 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class Association #:nodoc:
+        attr_reader :owners, :reflection, :preload_options, :model, :klass
+
+        def initialize(klass, owners, reflection, preload_options)
+          @klass           = klass
+          @owners          = owners
+          @reflection      = reflection
+          @preload_options = preload_options || {}
+          @model           = owners.first && owners.first.class
+          @scoped          = nil
+          @owners_by_key   = nil
+        end
+
+        def run
+          unless owners.first.association(reflection.name).loaded?
+            preload
+          end
+        end
+
+        def preload
+          raise NotImplementedError
+        end
+
+        def scoped
+          @scoped ||= build_scope
+        end
+
+        def records_for(ids)
+          scoped.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
+
+        # We're converting to a string here because postgres will return the aliased association
+        # key in a habtm as a string (for whatever reason)
+        def owners_by_key
+          @owners_by_key ||= owners.group_by do |owner|
+            key = owner[owner_key_name]
+            key && key.to_s
+          end
+        end
+
+        def options
+          reflection.options
+        end
+
+        private
+
+        def associated_records_by_owner
+          owner_keys = owners.map { |owner| owner[owner_key_name] }.compact.uniq
+
+          if klass.nil? || owner_keys.empty?
+            records = []
+          else
+            # 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(model.connection.in_clause_length || owner_keys.size)
+            records = sliced.map { |slice| records_for(slice) }.flatten
+          end
+
+          # Each record may have multiple owners, and vice-versa
+          records_by_owner = Hash[owners.map { |owner| [owner, []] }]
+          records.each do |record|
+            owner_key = record[association_key_name].to_s
+
+            owners_by_key[owner_key].each do |owner|
+              records_by_owner[owner] << record
+            end
+          end
+          records_by_owner
+        end
+
+        def build_scope
+          scope = klass.scoped
+
+          scope = scope.where(process_conditions(options[:conditions]))
+          scope = scope.where(process_conditions(preload_options[:conditions]))
+
+          scope = scope.select(preload_options[:select] || options[:select] || table[Arel.star])
+          scope = scope.includes(preload_options[:include] || options[:include])
+
+          if options[:as]
+            scope = scope.where(
+              klass.table_name => {
+                reflection.type => model.base_class.sti_name
+              }
+            )
+          end
+
+          scope
+        end
+
+        def process_conditions(conditions)
+          if conditions.respond_to?(:to_proc)
+            conditions = klass.send(:instance_eval, &conditions)
+          end
+
+          if conditions
+            klass.send(:sanitize_sql, conditions)
+          end
+        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..c248aeaaf6
--- /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_options[:order] || options[:order])
+        end
+
+        def preload
+          associated_records_by_owner.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_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/preloader/has_and_belongs_to_many.rb
new file mode 100644
index 0000000000..e794f05340
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_and_belongs_to_many.rb
@@ -0,0 +1,58 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasAndBelongsToMany < CollectionAssociation #:nodoc:
+        attr_reader :join_table
+
+        def initialize(klass, records, reflection, preload_options)
+          super
+          @join_table = Arel::Table.new(options[:join_table]).alias('t0')
+        end
+
+        # Unlike the other associations, we want to get a raw array of rows so that we can
+        # access the aliased column on the join table
+        def records_for(ids)
+          scope = super
+          klass.connection.select_all(scope.arel.to_sql, 'SQL', scope.bind_values)
+        end
+
+        def owner_key_name
+          reflection.active_record_primary_key
+        end
+
+        def association_key_name
+          'ar_association_key_name'
+        end
+
+        def association_key
+          join_table[reflection.foreign_key]
+        end
+
+        private
+
+        # Once we have used the join table column (in super), we manually instantiate the
+        # actual records
+        def associated_records_by_owner
+          super.each do |owner_key, rows|
+            rows.map! { |row| klass.instantiate(row) }
+          end
+        end
+
+        def build_scope
+          super.joins(join).select(join_select)
+        end
+
+        def join_select
+          association_key.as(Arel.sql(association_key_name))
+        end
+
+        def join
+          condition = table[reflection.association_primary_key].eq(
+            join_table[reflection.association_foreign_key])
+
+          table.create_join(join_table, table.create_on(condition))
+        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..c6e9ede356
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/has_many_through.rb
@@ -0,0 +1,15 @@
+module ActiveRecord
+  module Associations
+    class Preloader
+      class HasManyThrough < CollectionAssociation #:nodoc:
+        include ThroughAssociation
+
+        def associated_records_by_owner
+          super.each do |owner, records|
+            records.uniq! if options[:uniq]
+          end
+        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..848448bb48
--- /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_options[:order] || options[: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..44e804d785
--- /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
+          associated_records_by_owner.each do |owner, associated_records|
+            record = associated_records.first
+
+            association = owner.association(reflection.name)
+            association.target = record
+            association.set_inverse_instance(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..ad6374d09a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/preloader/through_association.rb
@@ -0,0 +1,67 @@
+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
+          through_records = through_records_by_owner
+
+          ActiveRecord::Associations::Preloader.new(
+            through_records.values.flatten,
+            source_reflection.name, options
+          ).run
+
+          through_records.each do |owner, records|
+            records.map! { |r| r.send(source_reflection.name) }.flatten!
+            records.compact!
+          end
+        end
+
+        private
+
+        def through_records_by_owner
+          ActiveRecord::Associations::Preloader.new(
+            owners, through_reflection.name,
+            through_options
+          ).run
+
+          Hash[owners.map do |owner|
+            through_records = Array.wrap(owner.send(through_reflection.name))
+
+            # Dont cache the association - we would only be caching a subset
+            if reflection.options[:source_type] && through_reflection.collection?
+              owner.association(through_reflection.name).reset
+            end
+
+            [owner, through_records]
+          end]
+        end
+
+        def through_options
+          through_options = {}
+
+          if options[:source_type]
+            through_options[:conditions] = { reflection.foreign_type => options[:source_type] }
+          else
+            if options[:conditions]
+              through_options[:include]    = options[:include] || options[:source]
+              through_options[:conditions] = options[:conditions]
+            end
+
+            through_options[:order] = options[:order]
+          end
+
+          through_options
+        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..0d8e45adb5
--- /dev/null
+++ b/activerecord/lib/active_record/associations/singular_association.rb
@@ -0,0 +1,55 @@
+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.items= for Foo.has_many :items
+      def writer(record)
+        replace(record)
+      end
+
+      def create(attributes = {})
+        new_record(:create, attributes)
+      end
+
+      def create!(attributes = {})
+        build(attributes).tap { |record| record.save! }
+      end
+
+      def build(attributes = {})
+        new_record(:build, attributes)
+      end
+
+      private
+
+        def find_target
+          scoped.first.tap { |record| set_inverse_instance(record) }
+        end
+
+        # Implemented by subclasses
+        def replace(record)
+          raise NotImplementedError
+        end
+
+        def set_new_record(record)
+          replace(record)
+        end
+
+        def new_record(method, attributes)
+          attributes = scoped.scope_for_create.merge(attributes || {})
+          record = reflection.send("#{method}_association", attributes)
+          set_new_record(record)
+          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..ed24373cba
--- /dev/null
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -0,0 +1,281 @@
+require 'enumerator'
+
+module ActiveRecord
+  # = Active Record Through Association
+  module Associations
+    module ThroughAssociation #:nodoc:
+
+      delegate :source_options, :through_options, :source_reflection, :through_reflection,
+               :through_reflection_chain, :through_conditions, :to => :reflection
+
+      protected
+
+        def target_scope
+          super.merge(through_reflection.klass.scoped)
+        end
+
+        def association_scope
+          scope = super.joins(construct_joins)
+          scope = scope.where(reflection_conditions(0))
+
+          unless options[:include]
+            scope = scope.includes(source_options[:include])
+          end
+
+          scope
+        end
+
+      private
+
+        # This scope affects the creation of the associated records (not the join records). At the
+        # moment we only support creating on a :through association when the source reflection is a
+        # belongs_to. Thus it's not necessary to set a foreign key on the associated record(s), so
+        # this scope has can legitimately be empty.
+        def creation_attributes
+          { }
+        end
+
+        # TODO: Needed?
+        def aliased_through_table
+          name = through_reflection.table_name
+
+          reflection.table_name == name ?
+            through_reflection.klass.arel_table.alias(name + "_join") :
+            through_reflection.klass.arel_table
+        end
+
+        def construct_owner_conditions
+          reflection = through_reflection_chain.last
+
+          if reflection.macro == :has_and_belongs_to_many
+            table = tables[reflection].first
+          else
+            table = Array.wrap(tables[reflection]).first
+          end
+
+          super(table, reflection)
+        end
+
+        def construct_joins
+          joins, right_index = [], 1
+
+          # Iterate over each pair in the through reflection chain, joining them together
+          through_reflection_chain.each_cons(2) do |left, right|
+            left_table, right_table = tables[left], tables[right]
+
+            if left.source_reflection.nil?
+              case left.macro
+                when :belongs_to
+                  joins << inner_join(
+                    right_table,
+                    left_table[left.association_primary_key],
+                    right_table[left.foreign_key],
+                    reflection_conditions(right_index)
+                  )
+                when :has_many, :has_one
+                  joins << inner_join(
+                    right_table,
+                    left_table[left.foreign_key],
+                    right_table[right.association_primary_key],
+                    polymorphic_conditions(left, left),
+                    reflection_conditions(right_index)
+                  )
+                when :has_and_belongs_to_many
+                  joins << inner_join(
+                    right_table,
+                    left_table.first[left.foreign_key],
+                    right_table[right.klass.primary_key],
+                    reflection_conditions(right_index)
+                  )
+              end
+            else
+              case left.source_reflection.macro
+                when :belongs_to
+                  joins << inner_join(
+                    right_table,
+                    left_table[left.association_primary_key],
+                    right_table[left.foreign_key],
+                    source_type_conditions(left),
+                    reflection_conditions(right_index)
+                  )
+                when :has_many, :has_one
+                  if right.macro == :has_and_belongs_to_many
+                    join_table, right_table = tables[right]
+                  end
+
+                  joins << inner_join(
+                    right_table,
+                    left_table[left.foreign_key],
+                    right_table[left.source_reflection.active_record_primary_key],
+                    polymorphic_conditions(left, left.source_reflection),
+                    reflection_conditions(right_index)
+                  )
+
+                  if right.macro == :has_and_belongs_to_many
+                    joins << inner_join(
+                      join_table,
+                      right_table[right.klass.primary_key],
+                      join_table[right.association_foreign_key]
+                    )
+                  end
+                when :has_and_belongs_to_many
+                  join_table, left_table = tables[left]
+
+                  joins << inner_join(
+                    join_table,
+                    left_table[left.klass.primary_key],
+                    join_table[left.association_foreign_key]
+                  )
+
+                  joins << inner_join(
+                    right_table,
+                    join_table[left.foreign_key],
+                    right_table[right.klass.primary_key],
+                    reflection_conditions(right_index)
+                  )
+              end
+            end
+
+            right_index += 1
+          end
+
+          joins
+        end
+
+        # 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)
+          if source_reflection.macro != :belongs_to
+            raise HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(owner, reflection)
+          end
+
+          join_attributes = {
+            source_reflection.foreign_key =>
+              records.map { |record|
+                record.send(source_reflection.association_primary_key)
+              }
+          }
+
+          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
+
+        def alias_tracker
+          @alias_tracker ||= AliasTracker.new
+        end
+
+        # TODO: It is decidedly icky to have an array for habtm entries, and no array for others
+        def tables
+          @tables ||= begin
+            Hash[
+              through_reflection_chain.map do |reflection|
+                table = alias_tracker.aliased_table_for(
+                  reflection.table_name,
+                  table_alias_for(reflection, reflection != self.reflection)
+                )
+
+                if reflection.macro == :has_and_belongs_to_many ||
+                     (reflection.source_reflection &&
+                      reflection.source_reflection.macro == :has_and_belongs_to_many)
+
+                  join_table = alias_tracker.aliased_table_for(
+                    (reflection.source_reflection || reflection).options[:join_table],
+                    table_alias_for(reflection, true)
+                  )
+
+                  [reflection, [join_table, table]]
+                else
+                  [reflection, table]
+                end
+              end
+            ]
+          end
+        end
+
+        def table_alias_for(reflection, join = false)
+          name = alias_tracker.pluralize(reflection.name)
+          name << "_#{self.reflection.name}"
+          name << "_join" if join
+          name
+        end
+
+        def inner_join(table, left_column, right_column, *conditions)
+          conditions << left_column.eq(right_column)
+
+          table.create_join(
+            table,
+            table.create_on(table.create_and(conditions.flatten.compact)))
+        end
+
+        def reflection_conditions(index)
+          reflection = through_reflection_chain[index]
+          conditions = through_conditions[index].dup
+
+          # TODO: maybe this should go in Reflection#through_conditions directly?
+          unless reflection.klass.descends_from_active_record?
+            conditions << reflection.klass.send(:type_condition)
+          end
+
+          unless conditions.empty?
+            conditions.map! do |condition|
+              condition = reflection.klass.send(:sanitize_sql, interpolate(condition), reflection.table_name)
+              condition = Arel.sql(condition) unless condition.is_a?(Arel::Node)
+              condition
+            end
+
+            Arel::Nodes::And.new(conditions)
+          end
+        end
+
+        def polymorphic_conditions(reflection, polymorphic_reflection)
+          if polymorphic_reflection.options[:as]
+            tables[reflection][polymorphic_reflection.type].
+              eq(polymorphic_reflection.active_record.base_class.name)
+          end
+        end
+
+        def source_type_conditions(reflection)
+          if reflection.options[:source_type]
+            tables[reflection.through_reflection][reflection.foreign_type].
+              eq(reflection.options[:source_type])
+          end
+        end
+
+        # TODO: Think about this in the context of nested associations
+        def stale_state
+          if through_reflection.macro == :belongs_to
+            owner[through_reflection.foreign_key].to_s
+          end
+        end
+
+        def foreign_key_present?
+          through_reflection.macro == :belongs_to &&
+          !owner[through_reflection.foreign_key].nil?
+        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/associations/through_association_scope.rb b/activerecord/lib/active_record/associations/through_association_scope.rb
deleted file mode 100644
index f6d02a215f..0000000000
--- a/activerecord/lib/active_record/associations/through_association_scope.rb
+++ /dev/null
@@ -1,300 +0,0 @@
-require 'enumerator'
-
-module ActiveRecord
-  # = Active Record Through Association Scope
-  module Associations
-    module ThroughAssociationScope
-
-      protected
-
-      def construct_find_scope
-        {
-          :conditions => construct_conditions,
-          :joins      => construct_joins,
-          :include    => @reflection.options[:include] || @reflection.source_reflection.options[:include],
-          :select     => construct_select,
-          :order      => @reflection.options[:order],
-          :limit      => @reflection.options[:limit],
-          :readonly   => @reflection.options[:readonly]
-        }
-      end
-
-      def construct_create_scope
-        @reflection.nested? ? {} : construct_owner_attributes(@reflection)
-      end
-
-      # Build SQL conditions from attributes, qualified by table name.
-      def construct_conditions
-        reflection = @reflection.through_reflection_chain.last
-
-        if reflection.macro == :has_and_belongs_to_many
-          table_alias = table_aliases[reflection].first
-        else
-          table_alias = table_aliases[reflection]
-        end
-
-        parts = construct_quoted_owner_attributes(reflection).map do |attr, value|
-          "#{table_alias}.#{attr} = #{value}"
-        end
-        parts += reflection_conditions(0)
-
-        "(" + parts.join(') AND (') + ")"
-      end
-
-      # Associate attributes pointing to owner, quoted.
-      def construct_quoted_owner_attributes(reflection)
-        if as = reflection.options[:as]
-          { "#{as}_id" => owner_quoted_id(reflection),
-            "#{as}_type" => reflection.klass.quote_value(
-              @owner.class.base_class.name.to_s,
-              reflection.klass.columns_hash["#{as}_type"]) }
-        elsif reflection.macro == :belongs_to
-          { reflection.klass.primary_key => @owner.class.quote_value(@owner[reflection.primary_key_name]) }
-        else
-          { reflection.primary_key_name => owner_quoted_id(reflection) }
-        end
-      end
-
-      def construct_select(custom_select = nil)
-        distinct = "DISTINCT " if @reflection.options[:uniq]
-        custom_select || @reflection.options[:select] || "#{distinct}#{@reflection.quoted_table_name}.*"
-      end
-
-      def construct_joins(custom_joins = nil)
-        "#{construct_through_joins} #{@reflection.options[:joins]} #{custom_joins}"
-      end
-
-      def construct_through_joins
-        joins, right_index = [], 1
-
-        # Iterate over each pair in the through reflection chain, joining them together
-        @reflection.through_reflection_chain.each_cons(2) do |left, right|
-          right_table_and_alias = table_name_and_alias(right.quoted_table_name, table_aliases[right])
-
-          if left.source_reflection.nil?
-            case left.macro
-              when :belongs_to
-                joins << inner_join_sql(
-                  right_table_and_alias,
-                  table_aliases[left],  left.association_primary_key,
-                  table_aliases[right], left.primary_key_name,
-                  reflection_conditions(right_index)
-                )
-              when :has_many, :has_one
-                joins << inner_join_sql(
-                  right_table_and_alias,
-                  table_aliases[left],  left.primary_key_name,
-                  table_aliases[right], right.association_primary_key,
-                  polymorphic_conditions(left, left),
-                  reflection_conditions(right_index)
-                )
-              when :has_and_belongs_to_many
-                joins << inner_join_sql(
-                  right_table_and_alias,
-                  table_aliases[left].first, left.primary_key_name,
-                  table_aliases[right],      right.klass.primary_key,
-                  reflection_conditions(right_index)
-                )
-            end
-          else
-            case left.source_reflection.macro
-              when :belongs_to
-                joins << inner_join_sql(
-                  right_table_and_alias,
-                  table_aliases[left],  left.association_primary_key,
-                  table_aliases[right], left.primary_key_name,
-                  source_type_conditions(left),
-                  reflection_conditions(right_index)
-                )
-              when :has_many, :has_one
-                if right.macro == :has_and_belongs_to_many
-                  join_table, right_table = table_aliases[right]
-                  right_table_and_alias   = table_name_and_alias(right.quoted_table_name, right_table)
-                else
-                  right_table = table_aliases[right]
-                end
-
-                joins << inner_join_sql(
-                  right_table_and_alias,
-                  table_aliases[left], left.primary_key_name,
-                  right_table,         left.source_reflection.active_record_primary_key,
-                  polymorphic_conditions(left, left.source_reflection),
-                  reflection_conditions(right_index)
-                )
-
-                if right.macro == :has_and_belongs_to_many
-                  joins << inner_join_sql(
-                    table_name_and_alias(
-                      quote_table_name(right.options[:join_table]),
-                      join_table
-                    ),
-                    right_table, right.klass.primary_key,
-                    join_table,  right.association_foreign_key
-                  )
-                end
-              when :has_and_belongs_to_many
-                join_table, left_table = table_aliases[left]
-
-                joins << inner_join_sql(
-                  table_name_and_alias(
-                    quote_table_name(left.source_reflection.options[:join_table]),
-                    join_table
-                  ),
-                  left_table, left.klass.primary_key,
-                  join_table, left.association_foreign_key
-                )
-
-                joins << inner_join_sql(
-                  right_table_and_alias,
-                  join_table,           left.primary_key_name,
-                  table_aliases[right], right.klass.primary_key,
-                  reflection_conditions(right_index)
-                )
-            end
-          end
-
-          right_index += 1
-        end
-
-        joins.join(" ")
-      end
-
-      def alias_tracker
-        @alias_tracker ||= AliasTracker.new
-      end
-
-      def table_aliases
-        @table_aliases ||= begin
-          @reflection.through_reflection_chain.inject({}) do |aliases, reflection|
-            table_alias = quote_table_name(alias_tracker.aliased_name_for(
-              reflection.table_name,
-              table_alias_for(reflection, reflection != @reflection)
-            ))
-
-            if reflection.macro == :has_and_belongs_to_many ||
-                 (reflection.source_reflection &&
-                  reflection.source_reflection.macro == :has_and_belongs_to_many)
-
-              join_table_alias = quote_table_name(alias_tracker.aliased_name_for(
-                (reflection.source_reflection || reflection).options[:join_table],
-                table_alias_for(reflection, true)
-              ))
-
-              aliases[reflection] = [join_table_alias, table_alias]
-            else
-              aliases[reflection] = table_alias
-            end
-
-            aliases
-          end
-        end
-      end
-
-      def table_alias_for(reflection, join = false)
-        name = alias_tracker.pluralize(reflection.name)
-        name << "_#{@reflection.name}"
-        name << "_join" if join
-        name
-      end
-
-      def quote_table_name(table_name)
-        @reflection.klass.connection.quote_table_name(table_name)
-      end
-
-      def table_name_and_alias(table_name, table_alias)
-        "#{table_name} #{table_alias if table_alias != table_name}".strip
-      end
-
-      def inner_join_sql(table, on_left_table, on_left_key, on_right_table, on_right_key, *conditions)
-        conditions << "#{on_left_table}.#{on_left_key} = #{on_right_table}.#{on_right_key}"
-        conditions = conditions.flatten.compact
-        conditions = conditions.map { |sql| "(#{sql})" } * ' AND '
-
-        "INNER JOIN #{table} ON #{conditions}"
-      end
-
-      def reflection_conditions(index)
-        reflection            = @reflection.through_reflection_chain[index]
-        reflection_conditions = @reflection.through_conditions[index]
-
-        conditions = []
-
-        if reflection.options[:as].nil? && # reflection.klass is a Module if :as is used
-           reflection.klass.finder_needs_type_condition?
-          conditions << reflection.klass.send(:type_condition).to_sql
-        end
-
-        reflection_conditions.each do |condition|
-          sanitized_condition    = reflection.klass.send(:sanitize_sql, condition)
-          interpolated_condition = interpolate_sql(sanitized_condition)
-
-          if condition.is_a?(Hash)
-            interpolated_condition.gsub!(
-              @reflection.quoted_table_name,
-              reflection.quoted_table_name
-            )
-          end
-
-          conditions << interpolated_condition
-        end
-
-        conditions
-      end
-
-      def polymorphic_conditions(reflection, polymorphic_reflection)
-        if polymorphic_reflection.options[:as]
-          "%s.%s = %s" % [
-            table_aliases[reflection], "#{polymorphic_reflection.options[:as]}_type",
-            @owner.class.quote_value(polymorphic_reflection.active_record.base_class.name)
-          ]
-        end
-      end
-
-      def source_type_conditions(reflection)
-        if reflection.options[:source_type]
-          "%s.%s = %s" % [
-            table_aliases[reflection.through_reflection],
-            reflection.source_reflection.options[:foreign_type].to_s,
-            @owner.class.quote_value(reflection.options[:source_type])
-          ]
-        end
-      end
-
-      # Construct attributes for associate pointing to owner.
-      def construct_owner_attributes(reflection)
-        if as = reflection.options[:as]
-          { "#{as}_id" => @owner.id,
-            "#{as}_type" => @owner.class.base_class.name.to_s }
-        else
-          { reflection.primary_key_name => @owner.id }
-        end
-      end
-
-      # Construct attributes for :through pointing to owner and associate.
-      # This method is used when adding records to the association. Since this only makes sense for
-      # non-nested through associations, that's the only case we have to worry about here.
-      def construct_join_attributes(associate)
-        # TODO: revisit this to allow it for deletion, supposing dependent option is supported
-        raise ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(@owner, @reflection) if [:has_one, :has_many].include?(@reflection.source_reflection.macro)
-
-        join_attributes = construct_owner_attributes(@reflection.through_reflection).merge(@reflection.source_reflection.primary_key_name => associate.id)
-
-        if @reflection.options[:source_type]
-          join_attributes.merge!(@reflection.source_reflection.options[:foreign_type] => associate.class.base_class.name.to_s)
-        end
-
-        if @reflection.through_reflection.options[:conditions].is_a?(Hash)
-          join_attributes.merge!(@reflection.through_reflection.options[:conditions])
-        end
-
-        join_attributes
-      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_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index 4f4a0a5fee..5833c65893 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -10,7 +10,18 @@ module ActiveRecord
       # Generates all the attribute related methods for columns in the database
       # accessors, mutators and query methods.
       def define_attribute_methods
-        super(columns_hash.keys)
+        return if attribute_methods_generated?
+        super(column_names)
+        @attribute_methods_generated = true
+      end
+
+      def attribute_methods_generated?
+        @attribute_methods_generated ||= false
+      end
+
+      def undefine_attribute_methods(*args)
+        super
+        @attribute_methods_generated = false
       end
 
       # Checks whether the method is defined in the model or any of its subclasses
@@ -18,7 +29,11 @@ module ActiveRecord
       # method is defined by Active Record though.
       def instance_method_already_implemented?(method_name)
         method_name = method_name.to_s
-        @_defined_class_methods         ||= ancestors.first(ancestors.index(ActiveRecord::Base)).sum([]) { |m| m.instance_methods(false) | m.private_instance_methods(false) }.map {|m| m.to_s }.to_set
+        index = ancestors.index(ActiveRecord::Base) || ancestors.length
+        @_defined_class_methods         ||= ancestors.first(index).map { |m|
+          m.instance_methods(false) | m.private_instance_methods(false)
+        }.flatten.map {|m| m.to_s }.to_set
+
         @@_defined_activerecord_methods ||= defined_activerecord_methods
         raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord" if @@_defined_activerecord_methods.include?(method_name)
         @_defined_class_methods.include?(method_name)
@@ -27,9 +42,8 @@ module ActiveRecord
       def defined_activerecord_methods
         active_record = ActiveRecord::Base
         super_klass   = ActiveRecord::Base.superclass
-        methods =  active_record.public_instance_methods - super_klass.public_instance_methods
-        methods += active_record.private_instance_methods - super_klass.private_instance_methods
-        methods += active_record.protected_instance_methods - super_klass.protected_instance_methods
+        methods = (active_record.instance_methods - super_klass.instance_methods) +
+                  (active_record.private_instance_methods - super_klass.private_instance_methods)
         methods.map {|m| m.to_s }.to_set
       end
     end
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index c19a33faa8..3eff3d54e3 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -22,6 +22,8 @@ module ActiveRecord
         if status = super
           @previously_changed = changes
           @changed_attributes.clear
+        elsif IdentityMap.enabled?
+          IdentityMap.remove(self)
         end
         status
       end
@@ -32,6 +34,9 @@ module ActiveRecord
           @previously_changed = changes
           @changed_attributes.clear
         end
+        rescue
+          IdentityMap.remove(self) if IdentityMap.enabled?
+          raise
       end
 
       # <tt>reload</tt> the record and clears changed attributes.
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 75ae06f5e9..fcdd31ddea 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -14,26 +14,37 @@ module ActiveRecord
         # 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
-          reset_primary_key
+          @primary_key ||= reset_primary_key
         end
 
         def reset_primary_key #:nodoc:
-          key = get_primary_key(base_class.name)
+          key = self == base_class ? get_primary_key(base_class.name) :
+            base_class.primary_key
+
           set_primary_key(key)
           key
         end
 
         def get_primary_key(base_name) #:nodoc:
-          key = 'id'
+          return 'id' unless base_name && !base_name.blank?
+
           case primary_key_prefix_type
-            when :table_name
-              key = base_name.to_s.foreign_key(false)
-            when :table_name_with_underscore
-              key = base_name.to_s.foreign_key
+          when :table_name
+            base_name.foreign_key(false)
+          when :table_name_with_underscore
+            base_name.foreign_key
+          else
+            if ActiveRecord::Base != self && connection.table_exists?(table_name)
+              connection.primary_key(table_name)
+            else
+              'id'
+            end
           end
-          key
         end
 
+        attr_accessor :original_primary_key
+        attr_writer :primary_key
+
         # Sets the name of the primary key column to use to the given value,
         # or (if the value is nil or false) to the value returned by the given
         # block.
@@ -42,9 +53,12 @@ module ActiveRecord
         #     set_primary_key "sysid"
         #   end
         def set_primary_key(value = nil, &block)
-          define_attr_method :primary_key, value, &block
+          @primary_key ||= ''
+          self.original_primary_key = @primary_key
+          value &&= value.to_s
+          connection_pool.primary_keys[table_name] = value
+          self.primary_key = block_given? ? instance_eval(&block) : value
         end
-        alias :primary_key= :set_primary_key
       end
     end
   end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 506f6e878f..ab86d8bad1 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -20,7 +20,7 @@ module ActiveRecord
         # be cached. Usually caching only pays off for attributes with expensive conversion
         # methods, like time related columns (e.g. +created_at+, +updated_at+).
         def cache_attributes(*attribute_names)
-          attribute_names.each {|attr| cached_attributes << attr.to_s}
+          cached_attributes.merge attribute_names.map { |attr| attr.to_s }
         end
 
         # Returns the attributes which are cached. By default time related columns
@@ -39,7 +39,7 @@ module ActiveRecord
             if serialized_attributes.include?(attr_name)
               define_read_method_for_serialized_attribute(attr_name)
             else
-              define_read_method(attr_name.to_sym, attr_name, columns_hash[attr_name])
+              define_read_method(attr_name, attr_name, columns_hash[attr_name])
             end
 
             if attr_name == primary_key && attr_name != "id"
@@ -54,17 +54,17 @@ module ActiveRecord
 
           # Define read method for serialized attribute.
           def define_read_method_for_serialized_attribute(attr_name)
-            access_code = "@attributes_cache['#{attr_name}'] ||= unserialize_attribute('#{attr_name}')"
-            generated_attribute_methods.module_eval("def #{attr_name}; #{access_code}; end", __FILE__, __LINE__)
+            access_code = "@attributes_cache['#{attr_name}'] ||= @attributes['#{attr_name}']"
+            generated_attribute_methods.module_eval("def _#{attr_name}; #{access_code}; end; alias #{attr_name} _#{attr_name}", __FILE__, __LINE__)
           end
 
           # Define an attribute reader method.  Cope with nil column.
           def define_read_method(symbol, attr_name, column)
-            cast_code = column.type_cast_code('v') if column
-            access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
+            cast_code = column.type_cast_code('v')
+            access_code = "(v=@attributes['#{attr_name}']) && #{cast_code}"
 
             unless attr_name.to_s == self.primary_key.to_s
-              access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
+              access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
             end
 
             if cache_attribute?(attr_name)
@@ -106,14 +106,10 @@ module ActiveRecord
 
       # Returns the unserialized object of the attribute.
       def unserialize_attribute(attr_name)
-        unserialized_object = object_from_yaml(@attributes[attr_name])
+        coder = self.class.serialized_attributes[attr_name]
+        unserialized_object = coder.load(@attributes[attr_name])
 
-        if unserialized_object.is_a?(self.class.serialized_attributes[attr_name]) || unserialized_object.nil?
-          @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
-        else
-          raise SerializationTypeMismatch,
-            "#{attr_name} was supposed to be a #{self.class.serialized_attributes[attr_name]}, but was a #{unserialized_object.class.to_s}"
-        end
+        @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
       end
 
       private
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
index dc2785b6bf..76218d2a73 100644
--- a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -40,12 +40,13 @@ module ActiveRecord
           def define_method_attribute=(attr_name)
             if create_time_zone_conversion_attribute?(attr_name, columns_hash[attr_name])
               method_body, line = <<-EOV, __LINE__ + 1
-                def #{attr_name}=(time)
+                def #{attr_name}=(original_time)
+                  time = original_time.dup unless original_time.nil?
                   unless time.acts_like?(:time)
                     time = time.is_a?(String) ? Time.zone.parse(time) : time.to_time rescue time
                   end
                   time = time.in_time_zone rescue nil if time
-                  write_attribute(:#{attr_name}, time)
+                  write_attribute(:#{attr_name}, (time || original_time))
                 end
               EOV
               generated_attribute_methods.module_eval(method_body, __FILE__, line)
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index c3dda29d03..748cc99a62 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -116,28 +116,44 @@ module ActiveRecord
   module AutosaveAssociation
     extend ActiveSupport::Concern
 
-    ASSOCIATION_TYPES = %w{ has_one belongs_to has_many has_and_belongs_to_many }
+    ASSOCIATION_TYPES = %w{ HasOne HasMany BelongsTo HasAndBelongsToMany }
+
+    module AssociationBuilderExtension #:nodoc:
+      def self.included(base)
+        base.valid_options << :autosave
+      end
+
+      def build
+        reflection = super
+        model.send(:add_autosave_association_callbacks, reflection)
+        reflection
+      end
+    end
 
     included do
       ASSOCIATION_TYPES.each do |type|
-        send("valid_keys_for_#{type}_association") << :autosave
+        Associations::Builder.const_get(type).send(:include, AssociationBuilderExtension)
       end
     end
 
     module ClassMethods
       private
 
-      # def belongs_to(name, options = {})
-      #   super
-      #   add_autosave_association_callbacks(reflect_on_association(name))
-      # end
-      ASSOCIATION_TYPES.each do |type|
-        module_eval <<-CODE, __FILE__, __LINE__ + 1
-          def #{type}(name, options = {})
-            super
-            add_autosave_association_callbacks(reflect_on_association(name))
+      def define_non_cyclic_method(name, reflection, &block)
+        define_method(name) do |*args|
+          result = true; @_already_called ||= {}
+          # Loop prevention for validation of associations
+          unless @_already_called[[name, reflection.name]]
+            begin
+              @_already_called[[name, reflection.name]]=true
+              result = instance_eval(&block)
+            ensure
+              @_already_called[[name, reflection.name]]=false
+            end
           end
-        CODE
+
+          result
+        end
       end
 
       # Adds validation and save callbacks for the association as specified by
@@ -160,7 +176,7 @@ module ActiveRecord
           if collection
             before_save :before_save_collection_association
 
-            define_method(save_method) { save_collection_association(reflection) }
+            define_non_cyclic_method(save_method, reflection) { save_collection_association(reflection) }
             # Doesn't use after_save as that would save associations added in after_create/after_update twice
             after_create save_method
             after_update save_method
@@ -178,7 +194,7 @@ module ActiveRecord
               after_create save_method
               after_update save_method
             else
-              define_method(save_method) { save_belongs_to_association(reflection) }
+              define_non_cyclic_method(save_method, reflection) { save_belongs_to_association(reflection) }
               before_save save_method
             end
           end
@@ -186,7 +202,7 @@ module ActiveRecord
 
         if reflection.validate? && !method_defined?(validation_method)
           method = (collection ? :validate_collection_association : :validate_single_association)
-          define_method(validation_method) { send(method, reflection) }
+          define_non_cyclic_method(validation_method, reflection) { send(method, reflection) }
           validate validation_method
         end
       end
@@ -227,7 +243,7 @@ module ActiveRecord
     # 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 && association.target
       elsif autosave
         association.target.find_all { |record| record.changed_for_autosave? }
       else
@@ -247,9 +263,9 @@ module ActiveRecord
     # Validate the association if <tt>:validate</tt> or <tt>:autosave</tt> is
     # turned on for the association.
     def validate_single_association(reflection)
-      if (association = association_instance_get(reflection.name)) && !association.target.nil?
-        association_valid?(reflection, association)
-      end
+      association = association_instance_get(reflection.name)
+      record      = association && association.target
+      association_valid?(reflection, record) if record
     end
 
     # Validate the associated records if <tt>:validate</tt> or
@@ -266,12 +282,12 @@ module ActiveRecord
     # 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, association)
-      return true if association.destroyed? || association.marked_for_destruction?
+    def association_valid?(reflection, record)
+      return true if record.destroyed? || record.marked_for_destruction?
 
-      unless valid = association.valid?
+      unless valid = record.valid?
         if reflection.options[:autosave]
-          association.errors.each do |attribute, message|
+          record.errors.each do |attribute, message|
             attribute = "#{reflection.name}.#{attribute}"
             errors[attribute] << message
             errors[attribute].uniq!
@@ -303,23 +319,31 @@ module ActiveRecord
         autosave = reflection.options[:autosave]
 
         if records = associated_records_to_validate_or_save(association, @new_record_before_save, autosave)
+          begin
           records.each do |record|
             next if record.destroyed?
 
+            saved = true
+
             if autosave && record.marked_for_destruction?
-              association.destroy(record)
+              association.proxy.destroy(record)
             elsif autosave != false && (@new_record_before_save || record.new_record?)
               if autosave
-                saved = association.send(:insert_record, record, false, false)
+                saved = association.insert_record(record, false)
               else
-                association.send(:insert_record, record)
+                association.insert_record(record)
               end
             elsif autosave
               saved = record.save(:validate => false)
             end
 
-            raise ActiveRecord::Rollback if saved == false
+            raise ActiveRecord::Rollback unless saved
+          end
+          rescue
+            records.each {|x| IdentityMap.remove(x) } if IdentityMap.enabled?
+            raise
           end
+
         end
 
         # reconstruct the scope now that we know the owner's id
@@ -336,16 +360,18 @@ module ActiveRecord
     # 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)
-      if (association = association_instance_get(reflection.name)) && !association.target.nil? && !association.destroyed?
+      association = association_instance_get(reflection.name)
+      record      = association && association.load_target
+      if record && !record.destroyed?
         autosave = reflection.options[:autosave]
 
-        if autosave && association.marked_for_destruction?
-          association.destroy
+        if autosave && record.marked_for_destruction?
+          record.destroy
         else
           key = reflection.options[:primary_key] ? send(reflection.options[:primary_key]) : id
-          if autosave != false && (new_record? || association.new_record? || association[reflection.primary_key_name] != key || autosave)
-            association[reflection.primary_key_name] = key
-            saved = association.save(:validate => !autosave)
+          if autosave != false && (new_record? || record.new_record? || record[reflection.foreign_key] != key || autosave)
+            record[reflection.foreign_key] = key
+            saved = record.save(:validate => !autosave)
             raise ActiveRecord::Rollback if !saved && autosave
             saved
           end
@@ -357,17 +383,20 @@ module ActiveRecord
     #
     # In addition, it will destroy the association if it was marked for destruction.
     def save_belongs_to_association(reflection)
-      if (association = association_instance_get(reflection.name)) && !association.destroyed?
+      association = association_instance_get(reflection.name)
+      record      = association && association.load_target
+      if record && !record.destroyed?
         autosave = reflection.options[:autosave]
 
-        if autosave && association.marked_for_destruction?
-          association.destroy
+        if autosave && record.marked_for_destruction?
+          record.destroy
         elsif autosave != false
-          saved = association.save(:validate => !autosave) if association.new_record? || autosave
+          saved = record.save(:validate => !autosave) if record.new_record? || (autosave && record.changed_for_autosave?)
 
           if association.updated?
-            association_id = association.send(reflection.options[:primary_key] || :id)
-            self[reflection.primary_key_name] = association_id
+            association_id = record.send(reflection.options[:primary_key] || :id)
+            self[reflection.foreign_key] = association_id
+            association.loaded!
           end
 
           saved if autosave
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 7b9ce21ceb..b3204b2bda 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1,3 +1,8 @@
+begin
+  require 'psych'
+rescue LoadError
+end
+
 require 'yaml'
 require 'set'
 require 'active_support/benchmarkable'
@@ -175,10 +180,7 @@ module ActiveRecord #:nodoc:
   # It's also possible to use multiple attributes in the same find by separating them with "_and_".
   #
   #  Person.where(:user_name => user_name, :password => password).first
-  #  Person.find_by_user_name_and_password #with dynamic finder
-  #
-  #  Person.where(:user_name => user_name, :password => password, :gender => 'male').first
-  #  Payment.find_by_user_name_and_password_and_gender
+  #  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.
   #
@@ -244,6 +246,17 @@ module ActiveRecord #:nodoc:
   #   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 by
@@ -527,11 +540,19 @@ module ActiveRecord #:nodoc:
       #
       # ==== Example
       #   # Serialize a preferences attribute
-      #   class User
+      #   class User < ActiveRecord::Base
       #     serialize :preferences
       #   end
       def serialize(attr_name, class_name = Object)
-        serialized_attributes[attr_name.to_s] = class_name
+        coder = if [:load, :dump].all? { |x| class_name.respond_to?(x) }
+                  class_name
+                else
+                  Coders::YAMLColumn.new(class_name)
+                end
+
+        # merge new serialized attribute and create new hash to ensure that each class in inheritance hierarchy
+        # has its own hash of own serialized attributes
+        self.serialized_attributes = serialized_attributes.merge(attr_name.to_s => coder)
       end
 
       # Guesses the table name (in forced lower-case) based on the name of the class in the
@@ -614,6 +635,9 @@ module ActiveRecord #:nodoc:
       def set_table_name(value = nil, &block)
         @quoted_table_name = nil
         define_attr_method :table_name, value, &block
+
+        @arel_table = Arel::Table.new(table_name, :engine => arel_engine)
+        @relation = Relation.new(self, arel_table)
       end
       alias :table_name= :set_table_name
 
@@ -657,16 +681,12 @@ module ActiveRecord #:nodoc:
 
       # Returns an array of column objects for the table associated with this class.
       def columns
-        unless defined?(@columns) && @columns
-          @columns = connection.columns(table_name, "#{name} Columns")
-          @columns.each { |column| column.primary = column.name == primary_key }
-        end
-        @columns
+        connection_pool.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 { |column| [column.name, column] }]
+        connection_pool.columns_hash[table_name]
       end
 
       # Returns an array of column names as strings.
@@ -723,8 +743,14 @@ module ActiveRecord #:nodoc:
       def reset_column_information
         connection.clear_cache!
         undefine_attribute_methods
-        @column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @inheritance_column = nil
-        @arel_engine = @relation = @arel_table = nil
+        connection_pool.clear_table_cache!(table_name) if table_exists?
+
+        @column_names = @content_columns = @dynamic_methods_hash = @inheritance_column = nil
+        @arel_engine = @relation = nil
+      end
+
+      def clear_cache! # :nodoc:
+        connection_pool.clear_cache!
       end
 
       def attribute_method?(attribute)
@@ -762,7 +788,7 @@ module ActiveRecord #:nodoc:
         :true == (@finder_needs_type_condition ||= descends_from_active_record? ? :false : :true)
       end
 
-      # Returns a string like 'Post id:integer, title:string, body:text'
+      # Returns a string like 'Post(id:integer, title:string, body:text)'
       def inspect
         if self == Base
           super
@@ -790,6 +816,10 @@ module ActiveRecord #:nodoc:
         object.is_a?(self)
       end
 
+      def symbolized_base_class
+        @symbolized_base_class ||= base_class.to_s.to_sym
+      end
+
       # Returns the base AR subclass that this class descends from. 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.
@@ -823,13 +853,13 @@ module ActiveRecord #:nodoc:
       end
 
       def arel_table
-        @arel_table ||= Arel::Table.new(table_name, arel_engine)
+        Arel::Table.new(table_name, arel_engine)
       end
 
       def arel_engine
         @arel_engine ||= begin
           if self == ActiveRecord::Base
-            Arel::Table.engine
+            ActiveRecord::Base
           else
             connection_handler.connection_pools[name] ? self : superclass.arel_engine
           end
@@ -852,8 +882,8 @@ module ActiveRecord #:nodoc:
       #     limit(10) # Fires "SELECT * FROM posts LIMIT 10"
       #   }
       #
-      # It is recommended to use block form of unscoped because chaining unscoped with <tt>named_scope</tt>
-      # does not work. Assuming that <tt>published</tt> is a <tt>named_scope</tt> following two statements are same.
+      # It is recommended to use block form of unscoped because chaining unscoped with <tt>scope</tt>
+      # does not work. Assuming that <tt>published</tt> is a <tt>scope</tt> following two statements are same.
       #
       # Post.unscoped.published
       # Post.published
@@ -870,20 +900,51 @@ module ActiveRecord #:nodoc:
         reset_scoped_methods
       end
 
+      # Specifies how the record is loaded by +Marshal+.
+      #
+      # +_load+ sets an instance variable for each key in the hash it takes as input.
+      # Override this method if you require more complex marshalling.
+      def _load(data)
+        record = allocate
+        record.init_with(Marshal.load(data))
+        record
+      end
+
+
+      # Finder methods must instantiate through this method to work with the
+      # single-table inheritance model that makes it possible to create
+      # objects of different types from the same table.
+      def instantiate(record)
+        sti_class = find_sti_class(record[inheritance_column])
+        record_id = sti_class.primary_key && record[sti_class.primary_key]
+
+        if ActiveRecord::IdentityMap.enabled? && record_id
+          if (column = sti_class.columns_hash[sti_class.primary_key]) && column.number?
+            record_id = record_id.to_i
+          end
+          if instance = IdentityMap.get(sti_class, record_id)
+            instance.reinit_with('attributes' => record)
+          else
+            instance = sti_class.allocate.init_with('attributes' => record)
+            IdentityMap.add(instance)
+          end
+        else
+          instance = sti_class.allocate.init_with('attributes' => record)
+        end
+
+        instance
+      end
+
       private
 
         def relation #:nodoc:
           @relation ||= Relation.new(self, arel_table)
-          finder_needs_type_condition? ? @relation.where(type_condition) : @relation
-        end
 
-        # Finder methods must instantiate through this method to work with the
-        # single-table inheritance model that makes it possible to create
-        # objects of different types from the same table.
-        def instantiate(record)
-          model = find_sti_class(record[inheritance_column]).allocate
-          model.init_with('attributes' => record)
-          model
+          if finder_needs_type_condition?
+            @relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
+          else
+            @relation
+          end
         end
 
         def find_sti_class(type_name)
@@ -913,11 +974,10 @@ module ActiveRecord #:nodoc:
         end
 
         def type_condition
-          sti_column = arel_table[inheritance_column]
-          condition = sti_column.eq(sti_name)
-          descendants.each { |subclass| condition = condition.or(sti_column.eq(subclass.sti_name)) }
+          sti_column = arel_table[inheritance_column.to_sym]
+          sti_names  = ([self] + descendants).map { |model| model.sti_name }
 
-          condition
+          sti_column.in(sti_names)
         end
 
         # Guesses the table name, but does not decorate it with prefix and suffix information.
@@ -1364,6 +1424,8 @@ MSG
       # hence you can't have attributes that aren't part of the table columns.
       def initialize(attributes = nil)
         @attributes = attributes_from_column_definition
+        @association_cache = {}
+        @aggregation_cache = {}
         @attributes_cache = {}
         @new_record = true
         @readonly = false
@@ -1373,15 +1435,32 @@ MSG
         @changed_attributes = {}
 
         ensure_proper_type
+        set_serialized_attributes
 
         populate_with_current_scope_attributes
         self.attributes = attributes unless attributes.nil?
 
         result = yield self if block_given?
-        _run_initialize_callbacks
+        run_callbacks :initialize
         result
       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 # => { 'id' => nil, ... }
+      def encode_with(coder)
+        coder['attributes'] = attributes
+      end
+
       # Initialize an empty model object from +coder+.  +coder+ must contain
       # the attributes necessary for initializing an empty model object.  For
       # example:
@@ -1394,11 +1473,28 @@ MSG
       #   post.title # => 'hello world'
       def init_with(coder)
         @attributes = coder['attributes']
+
+        set_serialized_attributes
+
         @attributes_cache, @previously_changed, @changed_attributes = {}, {}, {}
+        @association_cache = {}
+        @aggregation_cache = {}
         @readonly = @destroyed = @marked_for_destruction = false
         @new_record = false
-        _run_find_callbacks
-        _run_initialize_callbacks
+        run_callbacks :find
+        run_callbacks :initialize
+
+        self
+      end
+
+      # Specifies how the record is dumped by +Marshal+.
+      #
+      # +_dump+ emits a marshalled hash which has been passed to +encode_with+. Override this
+      # method if you require more complex marshalling.
+      def _dump(level)
+        dump = {}
+        encode_with(dump)
+        Marshal.dump(dump)
       end
 
       # Returns a String, which Action Pack uses for constructing an URL to this
@@ -1490,8 +1586,10 @@ MSG
         attributes.each do |k, v|
           if k.include?("(")
             multi_parameter_attributes << [ k, v ]
+          elsif respond_to?("#{k}=")
+            send("#{k}=", v)
           else
-            respond_to?(:"#{k}=") ? send(:"#{k}=", v) : raise(UnknownAttributeError, "unknown attribute: #{k}")
+            raise(UnknownAttributeError, "unknown attribute: #{k}")
           end
         end
 
@@ -1531,7 +1629,7 @@ MSG
       # Returns true if the specified +attribute+ has been set by the user or by a database load and is neither
       # nil nor empty? (the latter only applies to objects that respond to empty?, most notably Strings).
       def attribute_present?(attribute)
-        !read_attribute(attribute).blank?
+        !_read_attribute(attribute).blank?
       end
 
       # Returns the column object for the named attribute.
@@ -1604,9 +1702,9 @@ MSG
           @changed_attributes[attr] = orig_value if field_changed?(attr, orig_value, @attributes[attr])
         end
 
-        clear_aggregation_cache
-        clear_association_cache
-        @attributes_cache   = {}
+        @aggregation_cache = {}
+        @association_cache = {}
+        @attributes_cache = {}
         @new_record  = true
 
         ensure_proper_type
@@ -1628,7 +1726,7 @@ MSG
       # Returns the contents of the record as a nicely formatted string.
       def inspect
         attributes_as_nice_string = self.class.column_names.collect { |name|
-          if has_attribute?(name) || new_record?
+          if has_attribute?(name)
             "#{name}: #{attribute_for_inspect(name)}"
           end
         }.compact.join(", ")
@@ -1652,6 +1750,13 @@ MSG
 
     private
 
+      def set_serialized_attributes
+        (@attributes.keys & self.class.serialized_attributes.keys).each do |key|
+          coder = self.class.serialized_attributes[key]
+          @attributes[key] = coder.load @attributes[key]
+        end
+      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
@@ -1673,17 +1778,25 @@ MSG
       # Returns a copy of the attributes hash where all the values have been safely quoted for use in
       # an Arel insert/update method.
       def arel_attributes_values(include_primary_key = true, include_readonly_attributes = true, attribute_names = @attributes.keys)
-        attrs = {}
+        attrs      = {}
+        klass      = self.class
+        arel_table = klass.arel_table
+
         attribute_names.each do |name|
           if (column = column_for_attribute(name)) && (include_primary_key || !column.primary)
 
             if include_readonly_attributes || (!include_readonly_attributes && !self.class.readonly_attributes.include?(name))
-              value = read_attribute(name)
 
-              if !value.nil? && self.class.serialized_attributes.key?(name)
-                value = YAML.dump value
-              end
-              attrs[self.class.arel_table[name]] = value
+              value = if coder = klass.serialized_attributes[name]
+                        coder.dump @attributes[name]
+                      else
+                        # FIXME: we need @attributes to be used consistently.
+                        # If the values stored in @attributes were already type
+                        # casted, this code could be simplified
+                        read_attribute(name)
+                      end
+
+              attrs[arel_table[name]] = value
             end
           end
         end
@@ -1695,12 +1808,6 @@ MSG
         self.class.connection.quote(value, column)
       end
 
-      # Interpolate custom SQL string in instance context.
-      # Optional record argument is meant for custom insert_sql.
-      def interpolate_sql(sql, record = nil)
-        instance_eval("%@#{sql.gsub('@', '\@')}@", __FILE__, __LINE__)
-      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
@@ -1807,27 +1914,20 @@ MSG
         end
       end
 
-      def object_from_yaml(string)
-        return string unless string.is_a?(String) && string =~ /^---/
-        YAML::load(string) rescue string
-      end
-
       def populate_with_current_scope_attributes
         if scope = self.class.send(:current_scoped_methods)
           create_with = scope.scope_for_create
           create_with.each { |att,value|
-            respond_to?(:"#{att}=") && send("#{att}=", value)
+            respond_to?("#{att}=") && send("#{att}=", value)
           }
         end
       end
 
       # Clear attributes and changed_attributes
       def clear_timestamp_attributes
-        %w(created_at created_on updated_at updated_on).each do |attribute_name|
-          if has_attribute?(attribute_name)
-            self[attribute_name] = nil
-            changed_attributes.delete(attribute_name)
-          end
+        all_timestamp_attributes_in_model.each do |attribute_name|
+          self[attribute_name] = nil
+          changed_attributes.delete(attribute_name)
         end
       end
   end
@@ -1850,7 +1950,9 @@ MSG
     include AttributeMethods::Dirty
     include ActiveModel::MassAssignmentSecurity
     include Callbacks, ActiveModel::Observing, Timestamp
-    include Associations, AssociationPreload, NamedScope
+    include Associations, NamedScope
+    include IdentityMap
+    include ActiveModel::SecurePassword
 
     # AutosaveAssociation needs to be included before Transactions, because we want
     # #save_with_autosave_associations to be wrapped inside a transaction.
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
index 47428cfd0f..ff4ce1b605 100644
--- a/activerecord/lib/active_record/callbacks.rb
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -25,9 +25,13 @@ module ActiveRecord
   # Check out <tt>ActiveRecord::Transactions</tt> for more details about <tt>after_commit</tt> and
   # <tt>after_rollback</tt>.
   #
-  # That's a total of ten callbacks, which gives you immense power to react and prepare for each state in the
+  # 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.
+  #
+  # That's a total of twelve callbacks, which gives 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>_on_create</tt> callback is replaced by the corresponding <tt>_on_update</tt> callback.
+  # except that each <tt>_create</tt> callback is replaced by the corresponding <tt>_update</tt> callback.
   #
   # Examples:
   #   class CreditCard < ActiveRecord::Base
@@ -185,14 +189,6 @@ module ActiveRecord
   #                    'puts "Evaluated after parents are destroyed"'
   #   end
   #
-  # == The +after_find+ and +after_initialize+ exceptions
-  #
-  # Because +after_find+ and +after_initialize+ are called for each object found and instantiated by a finder,
-  # such as <tt>Base.find(:all)</tt>, we've had to implement a simple performance constraint (50% more speed
-  # on a simple test case). Unlike all the other callbacks, +after_find+ and +after_initialize+ will only be
-  # run if an explicit implementation is defined (<tt>def after_find</tt>). In that case, all of the
-  # callback types will be called.
-  #
   # == <tt>before_validation*</tt> returning statements
   #
   # If the returning value of a +before_validation+ callback can be evaluated to +false+, the process will be
@@ -237,25 +233,25 @@ module ActiveRecord
     end
 
     def destroy #:nodoc:
-      _run_destroy_callbacks { super }
+      run_callbacks(:destroy) { super }
     end
 
     def touch(*) #:nodoc:
-      _run_touch_callbacks { super }
+      run_callbacks(:touch) { super }
     end
 
   private
 
     def create_or_update #:nodoc:
-      _run_save_callbacks { super }
+      run_callbacks(:save) { super }
     end
 
     def create #:nodoc:
-      _run_create_callbacks { super }
+      run_callbacks(:create) { super }
     end
 
     def update(*) #:nodoc:
-      _run_update_callbacks { super }
+      run_callbacks(:update) { super }
     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..fb59d9fb07
--- /dev/null
+++ b/activerecord/lib/active_record/coders/yaml_column.rb
@@ -0,0 +1,41 @@
+module ActiveRecord
+  # :stopdoc:
+  module Coders
+    class YAMLColumn
+      RESCUE_ERRORS = [ ArgumentError ]
+
+      if defined?(Psych) && defined?(Psych::SyntaxError)
+        RESCUE_ERRORS << Psych::SyntaxError
+      end
+
+      attr_accessor :object_class
+
+      def initialize(object_class = Object)
+        @object_class = object_class
+      end
+
+      def dump(obj)
+        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 =~ /^---/
+        begin
+          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
+        rescue *RESCUE_ERRORS
+          yaml
+        end
+      end
+    end
+  end
+  # :startdoc
+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
index cffa2387de..4297c26413 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -57,7 +57,9 @@ module ActiveRecord
     # * +wait_timeout+: number of seconds to block and wait for a connection
     #   before giving up and raising a timeout error (default 5 seconds).
     class ConnectionPool
+      attr_accessor :automatic_reconnect
       attr_reader :spec, :connections
+      attr_reader :columns, :columns_hash, :primary_keys, :tables
 
       # Creates a new ConnectionPool object. +spec+ is a ConnectionSpecification
       # object which describes database connection information (e.g. adapter,
@@ -81,6 +83,63 @@ module ActiveRecord
 
         @connections = []
         @checked_out = []
+        @automatic_reconnect = true
+        @tables = {}
+
+        @columns     = Hash.new do |h, table_name|
+          h[table_name] = with_connection do |conn|
+
+            # Fetch a list of columns
+            conn.columns(table_name, "#{table_name} Columns").tap do |columns|
+
+              # set primary key information
+              columns.each do |column|
+                column.primary = column.name == primary_keys[table_name]
+              end
+            end
+          end
+        end
+
+        @columns_hash = Hash.new do |h, table_name|
+          h[table_name] = Hash[columns[table_name].map { |col|
+            [col.name, col]
+          }]
+        end
+
+        @primary_keys = Hash.new do |h, table_name|
+          h[table_name] = with_connection do |conn|
+            table_exists?(table_name) ? conn.primary_key(table_name) : 'id'
+          end
+        end
+      end
+
+      # A cached lookup for table existence
+      def table_exists?(name)
+        return true if @tables.key? name
+
+        with_connection do |conn|
+          conn.tables.each { |table| @tables[table] = true }
+        end
+
+        @tables.key? name
+      end
+
+      # Clears out internal caches:
+      #
+      #   * columns
+      #   * columns_hash
+      #   * tables
+      def clear_cache!
+        @columns.clear
+        @columns_hash.clear
+        @tables.clear
+      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
       end
 
       # Retrieve the connection associated with the current thread, or call
@@ -212,7 +271,7 @@ module ActiveRecord
       # calling +checkout+ on this pool.
       def checkin(conn)
         @connection_mutex.synchronize do
-          conn.send(:_run_checkin_callbacks) do
+          conn.run_callbacks :checkin do
             @checked_out.delete conn
             @queue.signal
           end
@@ -232,6 +291,8 @@ module ActiveRecord
       end
 
       def checkout_new_connection
+        raise ConnectionNotEstablished unless @automatic_reconnect
+
         c = new_connection
         @connections << c
         checkout_and_verify(c)
@@ -330,7 +391,7 @@ module ActiveRecord
         pool = @connection_pools[klass.name]
         return nil unless pool
 
-        @connection_pools.delete_if { |key, value| value == pool }
+        pool.automatic_reconnect = false
         pool.disconnect!
         pool.spec.config
       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
index ee9a0af35c..5c1ce173c8 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/module/deprecation'
+
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
     module DatabaseStatements
@@ -229,6 +231,8 @@ module ActiveRecord
       #
       # This method *modifies* the +sql+ parameter.
       #
+      # This method is deprecated!! Stop using it!
+      #
       # ===== Examples
       #  add_limit_offset!('SELECT * FROM suppliers', {:limit => 10, :offset => 50})
       # generates
@@ -243,6 +247,7 @@ module ActiveRecord
         end
         sql
       end
+      deprecate :add_limit_offset!
 
       def default_sequence_name(table, column)
         nil
@@ -256,7 +261,15 @@ module ActiveRecord
       # 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)
-        execute "INSERT INTO #{quote_table_name(table_name)} (#{fixture.key_list}) VALUES (#{fixture.value_list})", 'Fixture Insert'
+        columns = Hash[columns(table_name).map { |c| [c.name, c] }]
+
+        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
@@ -271,6 +284,25 @@ module ActiveRecord
         "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 =~ /,/
+          Arel.sql limit.to_s.split(',').map{ |i| Integer(i) }.join(',')
+        else
+          Integer(limit)
+        end
+      end
+
       protected
         # Returns an array of record hashes with the column names as keys and
         # column values as values.
@@ -294,21 +326,6 @@ module ActiveRecord
           update_sql(sql, name)
         end
 
-        # Sanitizes the given LIMIT parameter in order to prevent SQL injection.
-        #
-        # +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.
-        #
-        # 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.to_s =~ /,/
-            limit.to_s.split(',').map{ |i| i.to_i }.join(',')
-          else
-            limit.to_i
-          end
-        end
-
         # Send a rollback message to all records after they have been rolled back. If rollback
         # is false, only rollback records since the last save point.
         def rollback_transaction_records(rollback) #:nodoc
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
index d555308485..1db397f584 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
@@ -60,7 +60,7 @@ module ActiveRecord
           result =
             if @query_cache[sql].key?(binds)
               ActiveSupport::Notifications.instrument("sql.active_record",
-                :sql => sql, :name => "CACHE", :connection_id => self.object_id)
+                :sql => sql, :name => "CACHE", :connection_id => object_id)
               @query_cache[sql][binds]
             else
               @query_cache[sql][binds] = yield
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
index a7a12faac2..7489e88eef 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
@@ -33,8 +33,9 @@ module ActiveRecord
         when BigDecimal then value.to_s('F')
         when Numeric    then value.to_s
         when Date, Time then "'#{quoted_date(value)}'"
+        when Symbol     then "'#{quote_string(value.to_s)}'"
         else
-          "'#{quote_string(value.to_s)}'"
+          "'#{quote_string(value.to_yaml)}'"
         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
index 60ccf9edf3..7ac48c6646 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -6,264 +6,6 @@ require 'bigdecimal/util'
 
 module ActiveRecord
   module ConnectionAdapters #:nodoc:
-    # An abstract definition of a column in a table.
-    class Column
-      TRUE_VALUES = [true, 1, '1', 't', 'T', 'true', 'TRUE'].to_set
-      FALSE_VALUES = [false, 0, '0', 'f', 'F', 'false', 'FALSE'].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, :default, :type, :limit, :null, :sql_type, :precision, :scale
-      attr_accessor :primary
-
-      # 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>.
-      # +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, sql_type = nil, null = true)
-        @name, @sql_type, @null = name, sql_type, null
-        @limit, @precision, @scale = extract_limit(sql_type), extract_precision(sql_type), extract_scale(sql_type)
-        @type = simplified_type(sql_type)
-        @default = extract_default(default)
-
-        @primary = nil
-      end
-
-      # Returns +true+ if the column is either of type string or text.
-      def text?
-        type == :string || type == :text
-      end
-
-      # Returns +true+ if the column is either of type integer, float or decimal.
-      def number?
-        type == :integer || type == :float || type == :decimal
-      end
-
-      def has_default?
-        !default.nil?
-      end
-
-      # Returns the Ruby class that corresponds to the abstract data type.
-      def klass
-        case type
-          when :integer       then Fixnum
-          when :float         then Float
-          when :decimal       then BigDecimal
-          when :datetime      then Time
-          when :date          then Date
-          when :timestamp     then Time
-          when :time          then Time
-          when :text, :string then String
-          when :binary        then String
-          when :boolean       then Object
-        end
-      end
-
-      # Casts value (which is a String) to an appropriate instance.
-      def type_cast(value)
-        return nil if value.nil?
-        case type
-          when :string    then value
-          when :text      then value
-          when :integer   then value.to_i rescue value ? 1 : 0
-          when :float     then value.to_f
-          when :decimal   then self.class.value_to_decimal(value)
-          when :datetime  then self.class.string_to_time(value)
-          when :timestamp then self.class.string_to_time(value)
-          when :time      then self.class.string_to_dummy_time(value)
-          when :date      then self.class.string_to_date(value)
-          when :binary    then self.class.binary_to_string(value)
-          when :boolean   then self.class.value_to_boolean(value)
-          else value
-        end
-      end
-
-      def type_cast_code(var_name)
-        case type
-          when :string    then nil
-          when :text      then nil
-          when :integer   then "(#{var_name}.to_i rescue #{var_name} ? 1 : 0)"
-          when :float     then "#{var_name}.to_f"
-          when :decimal   then "#{self.class.name}.value_to_decimal(#{var_name})"
-          when :datetime  then "#{self.class.name}.string_to_time(#{var_name})"
-          when :timestamp then "#{self.class.name}.string_to_time(#{var_name})"
-          when :time      then "#{self.class.name}.string_to_dummy_time(#{var_name})"
-          when :date      then "#{self.class.name}.string_to_date(#{var_name})"
-          when :binary    then "#{self.class.name}.binary_to_string(#{var_name})"
-          when :boolean   then "#{self.class.name}.value_to_boolean(#{var_name})"
-          else nil
-        end
-      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 extract_default(default)
-        type_cast(default)
-      end
-
-      # Used to convert from Strings to BLOBs
-      def string_to_binary(value)
-        self.class.string_to_binary(value)
-      end
-
-      class << self
-        # Used to convert from Strings to BLOBs
-        def string_to_binary(value)
-          value
-        end
-
-        # Used to convert from BLOBs to Strings
-        def binary_to_string(value)
-          value
-        end
-
-        def string_to_date(string)
-          return string unless string.is_a?(String)
-          return nil if string.empty?
-
-          fast_string_to_date(string) || fallback_string_to_date(string)
-        end
-
-        def string_to_time(string)
-          return string unless string.is_a?(String)
-          return nil if string.empty?
-
-          fast_string_to_time(string) || fallback_string_to_time(string)
-        end
-
-        def string_to_dummy_time(string)
-          return string unless string.is_a?(String)
-          return nil if string.empty?
-
-          string_to_time "2000-01-01 #{string}"
-        end
-
-        # convert something to a boolean
-        def value_to_boolean(value)
-          if value.is_a?(String) && value.blank?
-            nil
-          else
-            TRUE_VALUES.include?(value)
-          end
-        end
-
-        # convert something to a BigDecimal
-        def value_to_decimal(value)
-          # Using .class is faster than .is_a? and
-          # subclasses of BigDecimal will be handled
-          # in the else clause
-          if value.class == BigDecimal
-            value
-          elsif value.respond_to?(:to_d)
-            value.to_d
-          else
-            value.to_s.to_d
-          end
-        end
-
-        protected
-          # '0.123456' -> 123456
-          # '1.123456' -> 123456
-          def microseconds(time)
-            ((time[:sec_fraction].to_f % 1) * 1_000_000).to_i
-          end
-
-          def new_date(year, mon, mday)
-            if year && year != 0
-              Date.new(year, mon, mday) rescue nil
-            end
-          end
-
-          def new_time(year, mon, mday, hour, min, sec, microsec)
-            # Treat 0000-00-00 00:00:00 as nil.
-            return nil if year.nil? || year == 0
-
-            Time.time_with_datetime_fallback(Base.default_timezone, year, mon, mday, hour, min, sec, microsec) rescue nil
-          end
-
-          def fast_string_to_date(string)
-            if string =~ Format::ISO_DATE
-              new_date $1.to_i, $2.to_i, $3.to_i
-            end
-          end
-
-          # Doesn't handle time zones.
-          def fast_string_to_time(string)
-            if string =~ Format::ISO_DATETIME
-              microsec = ($7.to_f * 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
-
-          def fallback_string_to_date(string)
-            new_date(*::Date._parse(string, false).values_at(:year, :mon, :mday))
-          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))
-          end
-      end
-
-      private
-        def extract_limit(sql_type)
-          $1.to_i if sql_type =~ /\((.*)\)/
-        end
-
-        def extract_precision(sql_type)
-          $2.to_i if sql_type =~ /^(numeric|decimal|number)\((\d+)(,\d+)?\)/i
-        end
-
-        def extract_scale(sql_type)
-          case sql_type
-            when /^(numeric|decimal|number)\((\d+)\)/i then 0
-            when /^(numeric|decimal|number)\((\d+)(,(\d+))\)/i then $4.to_i
-          end
-        end
-
-        def simplified_type(field_type)
-          case field_type
-            when /int/i
-              :integer
-            when /float|double/i
-              :float
-            when /decimal|numeric|number/i
-              extract_scale(field_type) == 0 ? :integer : :decimal
-            when /datetime/i
-              :datetime
-            when /timestamp/i
-              :timestamp
-            when /time/i
-              :time
-            when /date/i
-              :date
-            when /clob/i, /text/i
-              :text
-            when /blob/i, /binary/i
-              :binary
-            when /char/i, /string/i
-              :string
-            when /boolean/i
-              :boolean
-          end
-        end
-    end
-
     class IndexDefinition < Struct.new(:table, :name, :unique, :columns, :lengths) #:nodoc:
     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
index 5b9c48bafa..3ec7dd02a4 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -176,6 +176,13 @@ module ActiveRecord
       #    # 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.
+      #
       # ===== Examples
       # ====== Add a column
       #  change_table(:suppliers) do |t|
@@ -224,8 +231,14 @@ module ActiveRecord
       #
       # See also Table for details on
       # all of the various column transformation
-      def change_table(table_name)
-        yield Table.new(table_name, self)
+      def change_table(table_name, options = {})
+        if supports_bulk_alter? && options[:bulk]
+          recorder = ActiveRecord::Migration::CommandRecorder.new(self)
+          yield Table.new(table_name, recorder)
+          bulk_change_table(table_name, recorder.commands)
+        else
+          yield Table.new(table_name, self)
+        end
       end
 
       # Renames a table.
@@ -253,10 +266,7 @@ module ActiveRecord
       #  remove_column(:suppliers, :qualification)
       #  remove_columns(:suppliers, :qualification, :experience)
       def remove_column(table_name, *column_names)
-        raise ArgumentError.new("You must specify at least one column name.  Example: remove_column(:people, :first_name)") if column_names.empty?
-        column_names.flatten.each do |column_name|
-          execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{quote_column_name(column_name)}"
-        end
+        columns_for_remove(table_name, *column_names).each {|column_name| execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{column_name}" }
       end
       alias :remove_columns :remove_column
 
@@ -327,25 +337,8 @@ module ActiveRecord
       #
       # Note: SQLite doesn't support index length
       def add_index(table_name, column_name, options = {})
-        column_names = Array.wrap(column_name)
-        index_name   = index_name(table_name, :column => column_names)
-
-        if Hash === options # legacy support, since this param was a string
-          index_type = options[:unique] ? "UNIQUE" : ""
-          index_name = options[:name].to_s if options.key?(:name)
-        else
-          index_type = options
-        end
-
-        if index_name.length > index_name_length
-          raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{index_name_length} characters"
-        end
-        if index_name_exists?(table_name, index_name, false)
-          raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' already exists"
-        end
-        quoted_column_names = quoted_columns_for_index(column_names, options).join(", ")
-
-        execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{quoted_column_names})"
+        index_name, index_type, index_columns = 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})"
       end
 
       # Remove the given index from the table.
@@ -359,11 +352,7 @@ module ActiveRecord
       # Remove the index named by_branch_party in the accounts table.
       #   remove_index :accounts, :name => :by_branch_party
       def remove_index(table_name, options = {})
-        index_name = index_name(table_name, options)
-        unless index_name_exists?(table_name, index_name, true)
-          raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' does not exist"
-        end
-        remove_index!(table_name, index_name)
+        remove_index!(table_name, index_name_for_remove(table_name, options))
       end
 
       def remove_index!(table_name, index_name) #:nodoc:
@@ -469,7 +458,7 @@ module ActiveRecord
       end
 
       def type_to_sql(type, limit = nil, precision = nil, scale = nil) #:nodoc:
-        if native = native_database_types[type]
+        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
@@ -537,6 +526,45 @@ module ActiveRecord
           options.include?(:default) && !(options[:null] == false && options[:default].nil?)
         end
 
+        def add_index_options(table_name, column_name, options = {})
+          column_names = Array.wrap(column_name)
+          index_name   = index_name(table_name, :column => column_names)
+
+          if Hash === options # legacy support, since this param was a string
+            index_type = options[:unique] ? "UNIQUE" : ""
+            index_name = options[:name].to_s if options.key?(:name)
+          else
+            index_type = options
+          end
+
+          if index_name.length > index_name_length
+            raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{index_name_length} characters"
+          end
+          if 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]
+        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)
+            raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' does not exist"
+          end
+
+          index_name
+        end
+
+        def columns_for_remove(table_name, *column_names)
+          column_names = column_names.flatten
+
+          raise ArgumentError.new("You must specify at least one column name.  Example: remove_column(:people, :first_name)") if column_names.blank?
+          column_names.map {|column_name| quote_column_name(column_name) }
+        end
+
       private
       def table_definition
         TableDefinition.new(self)
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index 0282493219..0f44baa2fe 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -4,6 +4,7 @@ require 'bigdecimal/util'
 require 'active_support/core_ext/benchmark'
 
 # TODO: Autoload these files
+require 'active_record/connection_adapters/column'
 require 'active_record/connection_adapters/abstract/schema_definitions'
 require 'active_record/connection_adapters/abstract/schema_statements'
 require 'active_record/connection_adapters/abstract/database_statements'
@@ -77,8 +78,12 @@ module ActiveRecord
         false
       end
 
-      # Does this adapter support savepoints? PostgreSQL and MySQL do, SQLite
-      # does not.
+      def supports_bulk_alter?
+        false
+      end
+
+      # Does this adapter support savepoints? PostgreSQL and MySQL do,
+      # SQLite < 3.6.8 does not.
       def supports_savepoints?
         false
       end
@@ -204,11 +209,13 @@ module ActiveRecord
 
       protected
 
-        def log(sql, name = "SQL")
-          @instrumenter.instrument("sql.active_record",
-            :sql => sql, :name => name, :connection_id => object_id) do
-            yield
-          end
+        def log(sql, name = "SQL", binds = [])
+          @instrumenter.instrument(
+            "sql.active_record",
+            :sql           => sql,
+            :name          => name,
+            :connection_id => object_id,
+            :binds         => binds) { yield }
         rescue Exception => e
           message = "#{e.class.name}: #{e.message}: #{sql}"
           @logger.debug message if @logger
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..4e3d8a096f
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -0,0 +1,268 @@
+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'].to_set
+      FALSE_VALUES = [false, 0, '0', 'f', 'F', 'false', 'FALSE'].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, :default, :type, :limit, :null, :sql_type, :precision, :scale
+      attr_accessor :primary, :coder
+
+      alias :encoded? :coder
+
+      # 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>.
+      # +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, sql_type = nil, null = true)
+        @name      = name
+        @sql_type  = sql_type
+        @null      = null
+        @limit     = extract_limit(sql_type)
+        @precision = extract_precision(sql_type)
+        @scale     = extract_scale(sql_type)
+        @type      = simplified_type(sql_type)
+        @default   = extract_default(default)
+        @primary   = nil
+        @coder     = nil
+      end
+
+      # Returns +true+ if the column is either of type string or text.
+      def text?
+        type == :string || type == :text
+      end
+
+      # Returns +true+ if the column is either of type integer, float or decimal.
+      def number?
+        type == :integer || type == :float || type == :decimal
+      end
+
+      def has_default?
+        !default.nil?
+      end
+
+      # Returns the Ruby class that corresponds to the abstract data type.
+      def klass
+        case type
+        when :integer                     then Fixnum
+        when :float                       then Float
+        when :decimal                     then BigDecimal
+        when :datetime, :timestamp, :time then Time
+        when :date                        then Date
+        when :text, :string, :binary      then String
+        when :boolean                     then Object
+        end
+      end
+
+      # Casts value (which is a String) to an appropriate instance.
+      def type_cast(value)
+        return nil if value.nil?
+        return coder.load(value) if encoded?
+
+        klass = self.class
+
+        case type
+        when :string, :text        then value
+        when :integer              then value.to_i rescue value ? 1 : 0
+        when :float                then value.to_f
+        when :decimal              then klass.value_to_decimal(value)
+        when :datetime, :timestamp then klass.string_to_time(value)
+        when :time                 then klass.string_to_dummy_time(value)
+        when :date                 then klass.string_to_date(value)
+        when :binary               then klass.binary_to_string(value)
+        when :boolean              then klass.value_to_boolean(value)
+        else value
+        end
+      end
+
+      def type_cast_code(var_name)
+        klass = self.class.name
+
+        case type
+        when :string, :text        then var_name
+        when :integer              then "(#{var_name}.to_i rescue #{var_name} ? 1 : 0)"
+        when :float                then "#{var_name}.to_f"
+        when :decimal              then "#{klass}.value_to_decimal(#{var_name})"
+        when :datetime, :timestamp then "#{klass}.string_to_time(#{var_name})"
+        when :time                 then "#{klass}.string_to_dummy_time(#{var_name})"
+        when :date                 then "#{klass}.string_to_date(#{var_name})"
+        when :binary               then "#{klass}.binary_to_string(#{var_name})"
+        when :boolean              then "#{klass}.value_to_boolean(#{var_name})"
+        else var_name
+        end
+      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 extract_default(default)
+        type_cast(default)
+      end
+
+      # Used to convert from Strings to BLOBs
+      def string_to_binary(value)
+        self.class.string_to_binary(value)
+      end
+
+      class << self
+        # Used to convert from Strings to BLOBs
+        def string_to_binary(value)
+          value
+        end
+
+        # Used to convert from BLOBs to Strings
+        def binary_to_string(value)
+          value
+        end
+
+        def string_to_date(string)
+          return string unless string.is_a?(String)
+          return nil if string.empty?
+
+          fast_string_to_date(string) || fallback_string_to_date(string)
+        end
+
+        def string_to_time(string)
+          return string unless string.is_a?(String)
+          return nil if string.empty?
+
+          fast_string_to_time(string) || fallback_string_to_time(string)
+        end
+
+        def string_to_dummy_time(string)
+          return string unless string.is_a?(String)
+          return nil if string.empty?
+
+          string_to_time "2000-01-01 #{string}"
+        end
+
+        # convert something to a boolean
+        def value_to_boolean(value)
+          if value.is_a?(String) && value.blank?
+            nil
+          else
+            TRUE_VALUES.include?(value)
+          end
+        end
+
+        # convert something to a BigDecimal
+        def value_to_decimal(value)
+          # Using .class is faster than .is_a? and
+          # subclasses of BigDecimal will be handled
+          # in the else clause
+          if value.class == BigDecimal
+            value
+          elsif value.respond_to?(:to_d)
+            value.to_d
+          else
+            value.to_s.to_d
+          end
+        end
+
+        protected
+          # '0.123456' -> 123456
+          # '1.123456' -> 123456
+          def microseconds(time)
+            ((time[:sec_fraction].to_f % 1) * 1_000_000).to_i
+          end
+
+          def new_date(year, mon, mday)
+            if year && year != 0
+              Date.new(year, mon, mday) rescue nil
+            end
+          end
+
+          def new_time(year, mon, mday, hour, min, sec, microsec)
+            # Treat 0000-00-00 00:00:00 as nil.
+            return nil if year.nil? || year == 0
+
+            Time.time_with_datetime_fallback(Base.default_timezone, year, mon, mday, hour, min, sec, microsec) rescue nil
+          end
+
+          def fast_string_to_date(string)
+            if string =~ Format::ISO_DATE
+              new_date $1.to_i, $2.to_i, $3.to_i
+            end
+          end
+
+          # Doesn't handle time zones.
+          def fast_string_to_time(string)
+            if string =~ Format::ISO_DATETIME
+              microsec = ($7.to_f * 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
+
+          def fallback_string_to_date(string)
+            new_date(*::Date._parse(string, false).values_at(:year, :mon, :mday))
+          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))
+          end
+      end
+
+      private
+        def extract_limit(sql_type)
+          $1.to_i if sql_type =~ /\((.*)\)/
+        end
+
+        def extract_precision(sql_type)
+          $2.to_i if sql_type =~ /^(numeric|decimal|number)\((\d+)(,\d+)?\)/i
+        end
+
+        def extract_scale(sql_type)
+          case sql_type
+            when /^(numeric|decimal|number)\((\d+)\)/i then 0
+            when /^(numeric|decimal|number)\((\d+)(,(\d+))\)/i then $4.to_i
+          end
+        end
+
+        def simplified_type(field_type)
+          case field_type
+          when /int/i
+            :integer
+          when /float|double/i
+            :float
+          when /decimal|numeric|number/i
+            extract_scale(field_type) == 0 ? :integer : :decimal
+          when /datetime/i
+            :datetime
+          when /timestamp/i
+            :timestamp
+          when /time/i
+            :time
+          when /date/i
+            :date
+          when /clob/i, /text/i
+            :text
+          when /blob/i, /binary/i
+            :binary
+          when /char/i, /string/i
+            :string
+          when /boolean/i
+            :boolean
+          end
+        end
+    end
+  end
+  # :startdoc:
+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..7bad511c64
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -0,0 +1,610 @@
+# encoding: utf-8
+
+require 'mysql2'
+
+module ActiveRecord
+  class Base
+    def self.mysql2_connection(config)
+      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.symbolize_keys)
+      options = [config[:host], config[:username], config[:password], config[:database], config[:port], config[:socket], 0]
+      ConnectionAdapters::Mysql2Adapter.new(client, logger, options, config)
+    end
+  end
+
+  module ConnectionAdapters
+    class Mysql2IndexDefinition < Struct.new(:table, :name, :unique, :columns, :lengths) #:nodoc:
+    end
+
+    class Mysql2Column < Column
+      BOOL = "tinyint(1)"
+      def extract_default(default)
+        if sql_type =~ /blob/i || type == :text
+          if default.blank?
+            return null ? nil : ''
+          else
+            raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
+          end
+        elsif missing_default_forged_as_empty_string?(default)
+          nil
+        else
+          super
+        end
+      end
+
+      def has_default?
+        return false if sql_type =~ /blob/i || type == :text #mysql forbids defaults on blob and text columns
+        super
+      end
+
+      private
+        def simplified_type(field_type)
+          return :boolean if Mysql2Adapter.emulate_booleans && field_type.downcase.index(BOOL)
+
+          case field_type
+          when /enum/i, /set/i then :string
+          when /year/i         then :integer
+          when /bit/i          then :binary
+          else
+            super
+          end
+        end
+
+        def extract_limit(sql_type)
+          case sql_type
+          when /blob|text/i
+            case sql_type
+            when /tiny/i
+              255
+            when /medium/i
+              16777215
+            when /long/i
+              2147483647 # mysql only allows 2^31-1, not 2^32-1, somewhat inconsistently with the tiny/medium/normal cases
+            else
+              super # we could return 65535 here, but we leave it undecorated by default
+            end
+          when /^bigint/i;    8
+          when /^int/i;       4
+          when /^mediumint/i; 3
+          when /^smallint/i;  2
+          when /^tinyint/i;   1
+          else
+            super
+          end
+        end
+
+        # 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
+    end
+
+    class Mysql2Adapter < AbstractAdapter
+      cattr_accessor :emulate_booleans
+      self.emulate_booleans = true
+
+      ADAPTER_NAME = 'Mysql2'
+      PRIMARY = "PRIMARY"
+
+      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) DEFAULT NULL 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" },
+        :timestamp   => { :name => "datetime" },
+        :time        => { :name => "time" },
+        :date        => { :name => "date" },
+        :binary      => { :name => "blob" },
+        :boolean     => { :name => "tinyint", :limit => 1 }
+      }
+
+      def initialize(connection, logger, connection_options, config)
+        super(connection, logger)
+        @connection_options, @config = connection_options, config
+        @quoted_column_names, @quoted_table_names = {}, {}
+        configure_connection
+      end
+
+      def adapter_name
+        ADAPTER_NAME
+      end
+
+      def supports_migrations?
+        true
+      end
+
+      def supports_primary_key?
+        true
+      end
+
+      def supports_savepoints?
+        true
+      end
+
+      def native_database_types
+        NATIVE_DATABASE_TYPES
+      end
+
+      # QUOTING ==================================================
+
+      def quote(value, column = nil)
+        if value.kind_of?(String) && column && column.type == :binary && column.class.respond_to?(:string_to_binary)
+          s = column.class.string_to_binary(value).unpack("H*")[0]
+          "x'#{s}'"
+        elsif value.kind_of?(BigDecimal)
+          value.to_s("F")
+        else
+          super
+        end
+      end
+
+      def quote_column_name(name) #:nodoc:
+        @quoted_column_names[name] ||= "`#{name}`"
+      end
+
+      def quote_table_name(name) #:nodoc:
+        @quoted_table_names[name] ||= quote_column_name(name).gsub('.', '`.`')
+      end
+
+      def quote_string(string)
+        @connection.escape(string)
+      end
+
+      def quoted_true
+        QUOTED_TRUE
+      end
+
+      def quoted_false
+        QUOTED_FALSE
+      end
+
+      # REFERENTIAL INTEGRITY ====================================
+
+      def disable_referential_integrity(&block) #: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
+
+      # CONNECTION MANAGEMENT ====================================
+
+      def active?
+        return false unless @connection
+        @connection.ping
+      end
+
+      def reconnect!
+        disconnect!
+        connect
+      end
+
+      # this is set to true in 2.3, but we don't want it to be
+      def requires_reloading?
+        false
+      end
+
+      def disconnect!
+        unless @connection.nil?
+          @connection.close
+          @connection = nil
+        end
+      end
+
+      def reset!
+        disconnect!
+        connect
+      end
+
+      # DATABASE STATEMENTS ======================================
+
+      # 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)
+        execute(sql, name).to_a
+      end
+
+      # Executes the SQL statement in the context of this connection.
+      def execute(sql, name = nil)
+        # 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
+        if name == :skip_logging
+          @connection.query(sql)
+        else
+          log(sql, name) { @connection.query(sql) }
+        end
+      rescue ActiveRecord::StatementInvalid => exception
+        if exception.message.split(":").first =~ /Packets out of order/
+          raise ActiveRecord::StatementInvalid, "'Packets out of order' error was received from the database. Please update your mysql bindings (gem install mysql) and read http://dev.mysql.com/doc/mysql/en/password-hashing.html for more information.  If you're on Windows, use the Instant Rails installer to get the updated mysql bindings."
+        else
+          raise
+        end
+      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 update_sql(sql, name = nil)
+        super
+        @connection.affected_rows
+      end
+
+      def begin_db_transaction
+        execute "BEGIN"
+      rescue Exception
+        # Transactions aren't supported
+      end
+
+      def commit_db_transaction
+        execute "COMMIT"
+      rescue Exception
+        # Transactions aren't supported
+      end
+
+      def rollback_db_transaction
+        execute "ROLLBACK"
+      rescue Exception
+        # Transactions aren't supported
+      end
+
+      def create_savepoint
+        execute("SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def rollback_to_savepoint
+        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def release_savepoint
+        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def add_limit_offset!(sql, options)
+        limit, offset = options[:limit], options[:offset]
+        if limit && offset
+          sql << " LIMIT #{offset.to_i}, #{sanitize_limit(limit)}"
+        elsif limit
+          sql << " LIMIT #{sanitize_limit(limit)}"
+        elsif offset
+          sql << " OFFSET #{offset.to_i}"
+        end
+        sql
+      end
+      deprecate :add_limit_offset!
+
+      # SCHEMA STATEMENTS ========================================
+
+      def structure_dump
+        if supports_views?
+          sql = "SHOW FULL TABLES WHERE Table_type = 'BASE TABLE'"
+        else
+          sql = "SHOW TABLES"
+        end
+
+        select_all(sql).inject("") do |structure, table|
+          table.delete('Table_type')
+          structure += select_one("SHOW CREATE TABLE #{quote_table_name(table.to_a.first.last)}")["Create Table"] + ";\n\n"
+        end
+      end
+
+      def recreate_database(name, options = {})
+        drop_database(name)
+        create_database(name, options)
+      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
+
+      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)
+        tables = []
+        execute("SHOW TABLES", name).each do |field|
+          tables << field.first
+        end
+        tables
+      end
+
+      def drop_table(table_name, options = {})
+        super(table_name, options)
+      end
+
+      def indexes(table_name, name = nil)
+        indexes = []
+        current_index = nil
+        result = execute("SHOW KEYS FROM #{quote_table_name(table_name)}", name)
+        result.each(:symbolize_keys => true, :as => :hash) do |row|
+          if current_index != row[:Key_name]
+            next if row[:Key_name] == PRIMARY # skip the primary key
+            current_index = row[:Key_name]
+            indexes << Mysql2IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique] == 0, [], [])
+          end
+
+          indexes.last.columns << row[:Column_name]
+          indexes.last.lengths << row[:Sub_part]
+        end
+        indexes
+      end
+
+      def columns(table_name, name = nil)
+        sql = "SHOW FIELDS FROM #{quote_table_name(table_name)}"
+        columns = []
+        result = execute(sql)
+        result.each(:symbolize_keys => true, :as => :hash) { |field|
+          columns << Mysql2Column.new(field[:Field], field[:Default], field[:Type], field[:Null] == "YES")
+        }
+        columns
+      end
+
+      def create_table(table_name, options = {})
+        super(table_name, options.reverse_merge(:options => "ENGINE=InnoDB"))
+      end
+
+      def rename_table(table_name, new_name)
+        execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
+      end
+
+      def add_column(table_name, column_name, type, options = {})
+        add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+        add_column_options!(add_column_sql, options)
+        add_column_position!(add_column_sql, options)
+        execute(add_column_sql)
+      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 = {})
+        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
+
+        change_column_sql = "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+        add_column_options!(change_column_sql, options)
+        add_column_position!(change_column_sql, options)
+        execute(change_column_sql)
+      end
+
+      def rename_column(table_name, column_name, new_column_name)
+        options = {}
+        if column = columns(table_name).find { |c| c.name == column_name.to_s }
+          options[:default] = column.default
+          options[:null] = column.null
+        else
+          raise ActiveRecordError, "No such column: #{table_name}.#{column_name}"
+        end
+        current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'")["Type"]
+        rename_column_sql = "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}"
+        add_column_options!(rename_column_sql, options)
+        execute(rename_column_sql)
+      end
+
+      # Maps logical Rails types to MySQL-specific data types.
+      def type_to_sql(type, limit = nil, precision = nil, scale = nil)
+        return super unless type.to_s == '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
+      end
+
+      def add_column_position!(sql, options)
+        if options[:first]
+          sql << " FIRST"
+        elsif options[:after]
+          sql << " AFTER #{quote_column_name(options[:after])}"
+        end
+      end
+
+      def show_variable(name)
+        variables = select_all("SHOW VARIABLES LIKE '#{name}'")
+        variables.first['Value'] unless variables.empty?
+      end
+
+      def pk_and_sequence_for(table)
+        keys = []
+        result = execute("describe #{quote_table_name(table)}")
+        result.each(:symbolize_keys => true, :as => :hash) do |row|
+          keys << row[:Field] if row[:Key] == "PRI"
+        end
+        keys.length == 1 ? [keys.first, nil] : nil
+      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_equality_operator
+        "= BINARY"
+      end
+
+      def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
+        where_sql
+      end
+
+      protected
+        def quoted_columns_for_index(column_names, options = {})
+          length = options[:length] if options.is_a?(Hash)
+
+          quoted_column_names = case length
+          when Hash
+            column_names.map {|name| length[name] ? "#{quote_column_name(name)}(#{length[name]})" : quote_column_name(name) }
+          when Fixnum
+            column_names.map {|name| "#{quote_column_name(name)}(#{length})"}
+          else
+            column_names.map {|name| quote_column_name(name) }
+          end
+        end
+
+        def translate_exception(exception, message)
+          return super unless exception.respond_to?(:error_number)
+
+          case exception.error_number
+          when 1062
+            RecordNotUnique.new(message, exception)
+          when 1452
+            InvalidForeignKey.new(message, exception)
+          else
+            super
+          end
+        end
+
+      private
+        def connect
+          @connection = Mysql2::Client.new(@config)
+          configure_connection
+        end
+
+        def configure_connection
+          @connection.query_options.merge!(:as => :array)
+
+          # By default, MySQL 'where id is null' selects the last inserted id.
+          # Turn this off. http://dev.rubyonrails.org/ticket/6778
+          variable_assignments = ['SQL_AUTO_IS_NULL=0']
+          encoding = @config[:encoding]
+
+          # make sure we set the encoding
+          variable_assignments << "NAMES '#{encoding}'" if encoding
+
+          # increase timeout so mysql server doesn't disconnect us
+          wait_timeout = @config[:wait_timeout]
+          wait_timeout = 2592000 unless wait_timeout.is_a?(Fixnum)
+          variable_assignments << "@@wait_timeout = #{wait_timeout}"
+
+          execute("SET #{variable_assignments.join(', ')}", :skip_logging)
+        end
+
+        # Returns an array of record hashes with the column names as keys and
+        # column values as values.
+        def select(sql, name = nil)
+          execute(sql, name).each(:as => :hash)
+        end
+
+        def supports_views?
+          version[0] >= 5
+        end
+
+        def version
+          @version ||= @connection.info[:version].scan(/^(\d+)\.(\d+)\.(\d+)/).flatten.map { |v| v.to_i }
+        end
+
+        def column_for(table_name, column_name)
+          unless column = columns(table_name).find { |c| c.name == column_name.to_s }
+            raise "No such column: #{table_name}.#{column_name}"
+          end
+          column
+        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
index ce2352486b..368c5b2023 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -203,6 +203,10 @@ module ActiveRecord
         ADAPTER_NAME
       end
 
+      def supports_bulk_alter? #:nodoc:
+        true
+      end
+
       # Returns +true+ when the connection adapter supports prepared statement
       # caching, otherwise returns +false+
       def supports_statement_cache?
@@ -327,7 +331,7 @@ module ActiveRecord
       end
 
       def exec_query(sql, name = 'SQL', binds = [])
-        log(sql, name) do
+        log(sql, name, binds) do
           result = nil
 
           cache = {}
@@ -364,9 +368,14 @@ module ActiveRecord
         # statement API.  For those queries, we need to use this method. :'(
         log(sql, name) do
           result = @connection.query(sql)
-          cols = result.fetch_fields.map { |field| field.name }
-          rows = result.to_a
-          result.free
+          cols = []
+          rows = []
+
+          if result
+            cols = result.fetch_fields.map { |field| field.name }
+            rows = result.to_a
+            result.free
+          end
           ActiveRecord::Result.new(cols, rows)
         end
       end
@@ -400,7 +409,7 @@ module ActiveRecord
 
       def begin_db_transaction #:nodoc:
         exec_without_stmt "BEGIN"
-      rescue Exception
+      rescue Mysql::Error
         # Transactions aren't supported
       end
 
@@ -439,6 +448,7 @@ module ActiveRecord
         end
         sql
       end
+      deprecate :add_limit_offset!
 
       # SCHEMA STATEMENTS ========================================
 
@@ -527,7 +537,7 @@ module ActiveRecord
       def columns(table_name, name = nil)#:nodoc:
         sql = "SHOW FIELDS FROM #{quote_table_name(table_name)}"
         columns = []
-        result = execute(sql, :skip_logging)
+        result = execute(sql)
         result.each { |field| columns << MysqlColumn.new(field[0], field[4], field[1], field[2] == "YES") }
         result.free
         columns
@@ -541,11 +551,23 @@ module ActiveRecord
         execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
       end
 
+      def bulk_change_table(table_name, operations) #:nodoc:
+        sqls = operations.map do |command, args|
+          table, arguments = args.shift, args
+          method = :"#{command}_sql"
+
+          if respond_to?(method)
+            send(method, table, *arguments)
+          else
+            raise "Unknown method called : #{method}(#{arguments.inspect})"
+          end
+        end.flatten.join(", ")
+
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{sqls}")
+      end
+
       def add_column(table_name, column_name, type, options = {})
-        add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
-        add_column_options!(add_column_sql, options)
-        add_column_position!(add_column_sql, options)
-        execute(add_column_sql)
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{add_column_sql(table_name, column_name, type, options)}")
       end
 
       def change_column_default(table_name, column_name, default) #:nodoc:
@@ -564,34 +586,11 @@ module ActiveRecord
       end
 
       def change_column(table_name, column_name, type, options = {}) #:nodoc:
-        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
-
-        change_column_sql = "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
-        add_column_options!(change_column_sql, options)
-        add_column_position!(change_column_sql, options)
-        execute(change_column_sql)
+        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:
-        options = {}
-        if column = columns(table_name).find { |c| c.name == column_name.to_s }
-          options[:default] = column.default
-          options[:null] = column.null
-        else
-          raise ActiveRecordError, "No such column: #{table_name}.#{column_name}"
-        end
-        current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'")["Type"]
-        rename_column_sql = "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}"
-        add_column_options!(rename_column_sql, options)
-        execute(rename_column_sql)
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
       end
 
       # Maps logical Rails types to MySQL-specific data types.
@@ -674,6 +673,69 @@ module ActiveRecord
           end
         end
 
+        def add_column_sql(table_name, column_name, type, options = {})
+          add_column_sql = "ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+          add_column_options!(add_column_sql, options)
+          add_column_position!(add_column_sql, options)
+          add_column_sql
+        end
+
+        def remove_column_sql(table_name, *column_names)
+          columns_for_remove(table_name, *column_names).map {|column_name| "DROP #{column_name}" }
+        end
+        alias :remove_columns_sql :remove_column
+
+        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
+
+          change_column_sql = "CHANGE #{quote_column_name(column_name)} #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+          add_column_options!(change_column_sql, options)
+          add_column_position!(change_column_sql, options)
+          change_column_sql
+        end
+
+        def rename_column_sql(table_name, column_name, new_column_name)
+          options = {}
+
+          if column = columns(table_name).find { |c| c.name == column_name.to_s }
+            options[:default] = column.default
+            options[:null] = column.null
+          else
+            raise ActiveRecordError, "No such column: #{table_name}.#{column_name}"
+          end
+
+          current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'")["Type"]
+          rename_column_sql = "CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}"
+          add_column_options!(rename_column_sql, options)
+          rename_column_sql
+        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 connect
           encoding = @config[:encoding]
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index a4b1aa7154..576450bc3a 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -532,7 +532,7 @@ module ActiveRecord
       def exec_query(sql, name = 'SQL', binds = [])
         return exec_no_cache(sql, name) if binds.empty?
 
-        log(sql, name) do
+        log(sql, name, binds) do
           unless @statements.key? sql
             nextkey = "a#{@statements.length + 1}"
             @connection.prepare nextkey, sql
@@ -786,7 +786,7 @@ module ActiveRecord
       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, 'PK and serial sequence')[0]
+        result = exec_query(<<-end_sql, 'PK and serial sequence').rows.first
           SELECT attr.attname, seq.relname
           FROM pg_class      seq,
                pg_attribute  attr,
@@ -845,14 +845,18 @@ module ActiveRecord
       # 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 = {})
-        default = options[:default]
-        notnull = options[:null] == false
+        add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+        add_column_options!(add_column_sql, options)
 
-        # Add the column.
-        execute("ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}")
+        begin
+          execute add_column_sql
+        rescue ActiveRecord::StatementInvalid => e
+          raise e if postgresql_version > 80000
 
-        change_column_default(table_name, column_name, default) if options_include_default?(options)
-        change_column_null(table_name, column_name, false, default) if notnull
+          execute("ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}")
+          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
       end
 
       # Changes the column of a table.
@@ -1071,7 +1075,7 @@ module ActiveRecord
         #  - 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:
-          query <<-end_sql
+          exec_query(<<-end_sql).rows
             SELECT a.attname, format_type(a.atttypid, a.atttypmod), d.adsrc, a.attnotnull
               FROM pg_attribute a LEFT JOIN pg_attrdef d
                 ON a.attrelid = d.adrelid AND a.attnum = d.adnum
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
index d76fc4103e..9ee6b88ab6 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
@@ -62,6 +62,10 @@ module ActiveRecord
         sqlite_version >= '2.0.0'
       end
 
+      def supports_savepoints?
+        sqlite_version >= '3.6.8'
+      end
+
       # Returns +true+ when the connection adapter supports prepared statement
       # caching, otherwise returns +false+
       def supports_statement_cache?
@@ -144,12 +148,15 @@ module ActiveRecord
       # DATABASE STATEMENTS ======================================
 
       def exec_query(sql, name = nil, binds = [])
-        log(sql, name) do
+        log(sql, name, binds) do
 
           # Don't cache statements without bind values
           if binds.empty?
-            stmt = @connection.prepare(sql)
-            cols = stmt.columns
+            stmt    = @connection.prepare(sql)
+            cols    = stmt.columns
+            records = stmt.to_a
+            stmt.close
+            stmt = records
           else
             cache = @statements[sql] ||= {
               :stmt => @connection.prepare(sql)
@@ -189,6 +196,18 @@ module ActiveRecord
         exec_query(sql, name).rows
       end
 
+      def create_savepoint
+        execute("SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def rollback_to_savepoint
+        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def release_savepoint
+        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
+      end
+
       def begin_db_transaction #:nodoc:
         @connection.transaction
       end
@@ -217,6 +236,15 @@ module ActiveRecord
 
       def columns(table_name, name = nil) #:nodoc:
         table_structure(table_name).map do |field|
+          case field["dflt_value"]
+          when /^null$/i
+            field["dflt_value"] = nil
+          when /^'(.*)'$/
+            field["dflt_value"] = $1.gsub(/''/, "'")
+          when /^"(.*)"$/
+            field["dflt_value"] = $1.gsub(/""/, '"')
+          end
+
           SQLiteColumn.new(field['name'], field['dflt_value'], field['type'], field['notnull'].to_i == 0)
         end
       end
@@ -314,16 +342,11 @@ module ActiveRecord
 
       protected
         def select(sql, name = nil, binds = []) #:nodoc:
-          result = exec_query(sql, name, binds)
-          columns = result.columns.map { |column|
-            column.sub(/^"?\w+"?\./, '')
-          }
-
-          result.rows.map { |row| Hash[columns.zip(row)] }
+          exec_query(sql, name, binds).to_a
         end
 
         def table_structure(table_name)
-          structure = @connection.table_info(quote_table_name(table_name))
+          structure = exec_query("PRAGMA table_info(#{quote_table_name(table_name)})").to_hash
           raise(ActiveRecord::StatementInvalid, "Could not find table '#{table_name}'") if structure.empty?
           structure
         end
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
index 8180bf0987..7839f03848 100644
--- a/activerecord/lib/active_record/counter_cache.rb
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -74,6 +74,8 @@ module ActiveRecord
         "#{quoted_column} = COALESCE(#{quoted_column}, 0) #{operator} #{value.abs}"
       end
 
+      IdentityMap.remove_by_id(symbolized_base_class, id) if IdentityMap.enabled?
+
       update_all(updates.join(', '), primary_key => id )
     end
 
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 6fb723f2f5..d523c643ba 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -1,4 +1,10 @@
 require 'erb'
+
+begin
+  require 'psych'
+rescue LoadError
+end
+
 require 'yaml'
 require 'csv'
 require 'zlib'
@@ -6,15 +12,7 @@ require 'active_support/dependencies'
 require 'active_support/core_ext/array/wrap'
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/logger'
-
-if RUBY_VERSION < '1.9'
-  module YAML #:nodoc:
-    class Omap #:nodoc:
-      def keys;   map { |k, v| k } end
-      def values; map { |k, v| v } end
-    end
-  end
-end
+require 'active_support/ordered_hash'
 
 if defined? ActiveRecord
   class FixtureClassNotFound < ActiveRecord::ActiveRecordError #:nodoc:
@@ -446,20 +444,23 @@ class FixturesFileNotFound < StandardError; end
 #
 # Any fixture labeled "DEFAULTS" is safely ignored.
 
-class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
+class Fixtures
   MAX_ID = 2 ** 30 - 1
-  DEFAULT_FILTER_RE = /\.ya?ml$/
 
-  @@all_cached_fixtures = {}
+  @@all_cached_fixtures = Hash.new { |h,k| h[k] = {} }
 
-  def self.reset_cache(connection = nil)
-    connection ||= ActiveRecord::Base.connection
-    @@all_cached_fixtures[connection.object_id] = {}
+  def self.find_table_name(table_name) # :nodoc:
+    ActiveRecord::Base.pluralize_table_names ?
+      table_name.to_s.singularize.camelize :
+      table_name.to_s.camelize
+  end
+
+  def self.reset_cache
+    @@all_cached_fixtures.clear
   end
 
   def self.cache_for_connection(connection)
-    @@all_cached_fixtures[connection.object_id] ||= {}
-    @@all_cached_fixtures[connection.object_id]
+    @@all_cached_fixtures[connection]
   end
 
   def self.fixture_is_cached?(connection, table_name)
@@ -468,27 +469,23 @@ class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
 
   def self.cached_fixtures(connection, keys_to_fetch = nil)
     if keys_to_fetch
-      fixtures = cache_for_connection(connection).values_at(*keys_to_fetch)
+      cache_for_connection(connection).values_at(*keys_to_fetch)
     else
-      fixtures = cache_for_connection(connection).values
+      cache_for_connection(connection).values
     end
-    fixtures.size > 1 ? fixtures : fixtures.first
   end
 
   def self.cache_fixtures(connection, fixtures_map)
     cache_for_connection(connection).update(fixtures_map)
   end
 
-  def self.instantiate_fixtures(object, table_name, fixtures, load_instances = true)
-    object.instance_variable_set "@#{table_name.to_s.gsub('.','_')}", fixtures
+  def self.instantiate_fixtures(object, fixture_name, fixtures, load_instances = true)
     if load_instances
-      ActiveRecord::Base.silence do
-        fixtures.each do |name, fixture|
-          begin
-            object.instance_variable_set "@#{name}", fixture.find
-          rescue FixtureClassNotFound
-            nil
-          end
+      fixtures.each do |name, fixture|
+        begin
+          object.instance_variable_set "@#{name}", fixture.find
+        rescue FixtureClassNotFound
+          nil
         end
       end
     end
@@ -505,36 +502,56 @@ class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
 
   def self.create_fixtures(fixtures_directory, table_names, class_names = {})
     table_names = [table_names].flatten.map { |n| n.to_s }
-    table_names.each { |n| class_names[n.tr('/', '_').to_sym] = n.classify if n.include?('/') }
-    connection  = block_given? ? yield : ActiveRecord::Base.connection
+    table_names.each { |n|
+      class_names[n.tr('/', '_').to_sym] = n.classify if n.include?('/')
+    }
 
-    table_names_to_fetch = table_names.reject { |table_name| fixture_is_cached?(connection, table_name) }
+    # FIXME: Apparently JK uses this.
+    connection = block_given? ? yield : ActiveRecord::Base.connection
 
-    unless table_names_to_fetch.empty?
-      ActiveRecord::Base.silence do
-        connection.disable_referential_integrity do
-          fixtures_map = {}
+    files_to_read = table_names.reject { |table_name| fixture_is_cached?(connection, table_name) }
 
-          fixtures = table_names_to_fetch.map do |table_name|
-            fixtures_map[table_name] = Fixtures.new(connection, table_name.tr('/', '_'), class_names[table_name.tr('/', '_').to_sym], File.join(fixtures_directory, table_name))
-          end
+    unless files_to_read.empty?
+      connection.disable_referential_integrity do
+        fixtures_map = {}
+
+        fixture_files = files_to_read.map do |path|
+          table_name = path.tr '/', '_'
+
+          fixtures_map[path] = Fixtures.new(
+            connection,
+            table_name,
+            class_names[table_name.to_sym],
+            File.join(fixtures_directory, path))
+        end
+
+        all_loaded_fixtures.update(fixtures_map)
 
-          all_loaded_fixtures.update(fixtures_map)
+        connection.transaction(:requires_new => true) do
+          fixture_files.each do |ff|
+            conn = ff.model_class.respond_to?(:connection) ? ff.model_class.connection : connection
+            table_rows = ff.table_rows
 
-          connection.transaction(:requires_new => true) do
-            fixtures.reverse.each { |fixture| fixture.delete_existing_fixtures }
-            fixtures.each { |fixture| fixture.insert_fixtures }
+            table_rows.keys.each do |table|
+              conn.delete "DELETE FROM #{conn.quote_table_name(table)}", 'Fixture Delete'
+            end
 
-            # Cap primary key sequences to max(pk).
-            if connection.respond_to?(:reset_pk_sequence!)
-              table_names.each do |table_name|
-                connection.reset_pk_sequence!(table_name.tr('/', '_'))
+            table_rows.each do |table_name,rows|
+              rows.each do |row|
+                conn.insert_fixture(row, table_name)
               end
             end
           end
 
-          cache_fixtures(connection, fixtures_map)
+          # Cap primary key sequences to max(pk).
+          if connection.respond_to?(:reset_pk_sequence!)
+            table_names.each do |table_name|
+              connection.reset_pk_sequence!(table_name.tr('/', '_'))
+            end
+          end
         end
+
+        cache_fixtures(connection, fixtures_map)
       end
     end
     cached_fixtures(connection, table_names)
@@ -546,40 +563,59 @@ class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
     Zlib.crc32(label.to_s) % MAX_ID
   end
 
-  attr_reader :table_name, :name
+  attr_reader :table_name, :name, :fixtures, :model_class
+
+  def initialize(connection, table_name, class_name, fixture_path)
+    @connection   = connection
+    @table_name   = table_name
+    @fixture_path = fixture_path
+    @name         = table_name # preserve fixture base name
+    @class_name   = class_name
+
+    @fixtures     = ActiveSupport::OrderedHash.new
+    @table_name   = "#{ActiveRecord::Base.table_name_prefix}#{@table_name}#{ActiveRecord::Base.table_name_suffix}"
+
+    # Should be an AR::Base type class
+    if class_name.is_a?(Class)
+      @table_name   = class_name.table_name
+      @connection   = class_name.connection
+      @model_class  = class_name
+    else
+      @model_class  = class_name.constantize rescue nil
+    end
 
-  def initialize(connection, table_name, class_name, fixture_path, file_filter = DEFAULT_FILTER_RE)
-    @connection, @table_name, @fixture_path, @file_filter = connection, table_name, fixture_path, file_filter
-    @name = table_name # preserve fixture base name
-    @class_name = class_name ||
-                  (ActiveRecord::Base.pluralize_table_names ? @table_name.singularize.camelize : @table_name.camelize)
-    @table_name = "#{ActiveRecord::Base.table_name_prefix}#{@table_name}#{ActiveRecord::Base.table_name_suffix}"
-    @table_name = class_name.table_name if class_name.respond_to?(:table_name)
-    @connection = class_name.connection if class_name.respond_to?(:connection)
     read_fixture_files
   end
 
-  def delete_existing_fixtures
-    @connection.delete "DELETE FROM #{@connection.quote_table_name(table_name)}", 'Fixture Delete'
+  def [](x)
+    fixtures[x]
+  end
+
+  def []=(k,v)
+    fixtures[k] = v
+  end
+
+  def each(&block)
+    fixtures.each(&block)
+  end
+
+  def size
+    fixtures.size
   end
 
-  def insert_fixtures
+  # Return 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 = ActiveRecord::Base.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
-    if is_a?(Hash)
-      delete('DEFAULTS')
-    else
-      delete(assoc('DEFAULTS'))
-    end
+    fixtures.delete('DEFAULTS')
 
     # track any join tables we need to insert later
-    habtm_fixtures = Hash.new do |h, habtm|
-      h[habtm] = HabtmFixtures.new(@connection, habtm.options[:join_table], nil, nil)
-    end
+    rows = Hash.new { |h,table| h[table] = [] }
 
-    each do |label, fixture|
+    rows[table_name] = fixtures.map do |label, fixture|
       row = fixture.to_hash
 
       if model_class && model_class < ActiveRecord::Base
@@ -615,14 +651,9 @@ class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
             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.options[:polymorphic]
-                if value.sub!(/\s*\(([^\)]*)\)\s*$/, "")
-                  target_type = $1
-                  target_type_name = (association.options[:foreign_type] || "#{association.name}_type").to_s
-
-                  # support polymorphic belongs_to as "label (Type)"
-                  row[target_type_name] = target_type
-                end
+              if association.options[:polymorphic] && value.sub!(/\s*\(([^\)]*)\)\s*$/, "")
+                # support polymorphic belongs_to as "label (Type)"
+                row[association.foreign_type] = $1
               end
 
               row[fk_name] = Fixtures.identify(value)
@@ -630,47 +661,22 @@ class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
           when :has_and_belongs_to_many
             if (targets = row.delete(association.name.to_s))
               targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
-              join_fixtures = habtm_fixtures[association]
-
-              targets.each do |target|
-                join_fixtures["#{label}_#{target}"] = Fixture.new(
-                  { association.primary_key_name => row[primary_key_name],
-                    association.association_foreign_key => Fixtures.identify(target) },
-                  nil, @connection)
-              end
+              table_name = association.options[:join_table]
+              rows[table_name].concat targets.map { |target|
+                { association.foreign_key             => row[primary_key_name],
+                  association.association_foreign_key => Fixtures.identify(target) }
+              }
             end
           end
         end
       end
 
-      @connection.insert_fixture(fixture, @table_name)
-    end
-
-    # insert any HABTM join tables we discovered
-    habtm_fixtures.values.each do |fixture|
-      fixture.delete_existing_fixtures
-      fixture.insert_fixtures
+      row
     end
+    rows
   end
 
   private
-    class HabtmFixtures < ::Fixtures #:nodoc:
-      def read_fixture_files; end
-    end
-
-    def model_class
-      unless defined?(@model_class)
-        @model_class =
-          if @class_name.nil? || @class_name.is_a?(Class)
-            @class_name
-          else
-            @class_name.constantize rescue nil
-          end
-      end
-
-      @model_class
-    end
-
     def primary_key_name
       @primary_key_name ||= model_class && model_class.primary_key
     end
@@ -724,7 +730,7 @@ class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
               raise Fixture::FormatError, "Bad data for #{@class_name} fixture named #{name} (nil)"
             end
 
-            self[name] = Fixture.new(data, model_class, @connection)
+            fixtures[name] = Fixture.new(data, model_class)
           end
         end
       end
@@ -737,7 +743,7 @@ class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
       reader.each do |row|
         data = {}
         row.each_with_index { |cell, j| data[header[j].to_s.strip] = cell.to_s.strip }
-        self["#{@class_name.to_s.underscore}_#{i+=1}"] = Fixture.new(data, model_class, @connection)
+        fixtures["#{@class_name.to_s.underscore}_#{i+=1}"] = Fixture.new(data, model_class)
       end
     end
 
@@ -773,44 +779,30 @@ class Fixture #:nodoc:
   class FormatError < FixtureError #:nodoc:
   end
 
-  attr_reader :model_class
+  attr_reader :model_class, :fixture
 
-  def initialize(fixture, model_class, connection = ActiveRecord::Base.connection)
-    @connection = connection
-    @fixture = fixture
-    @model_class = model_class.is_a?(Class) ? model_class : model_class.constantize rescue nil
+  def initialize(fixture, model_class)
+    @fixture     = fixture
+    @model_class = model_class
   end
 
   def class_name
-    @model_class.name if @model_class
+    model_class.name if model_class
   end
 
   def each
-    @fixture.each { |item| yield item }
+    fixture.each { |item| yield item }
   end
 
   def [](key)
-    @fixture[key]
-  end
-
-  def to_hash
-    @fixture
+    fixture[key]
   end
 
-  def key_list
-    @fixture.keys.map { |column_name| @connection.quote_column_name(column_name) }.join(', ')
-  end
-
-  def value_list
-    cols = (model_class && model_class < ActiveRecord::Base) ? model_class.columns_hash : {}
-    @fixture.map do |key, value|
-      @connection.quote(value, cols[key]).gsub('[^\]\\n', "\n").gsub('[^\]\\r', "\r")
-    end.join(', ')
-  end
+  alias :to_hash :fixture
 
   def find
     if model_class
-      model_class.find(self[model_class.primary_key])
+      model_class.find(fixture[model_class.primary_key])
     else
       raise FixtureClassNotFound, "No class attached to find."
     end
@@ -837,7 +829,9 @@ module ActiveRecord
       self.use_instantiated_fixtures = false
       self.pre_loaded_fixtures = false
 
-      self.fixture_class_names = {}
+      self.fixture_class_names = Hash.new do |h, table_name|
+        h[table_name] = Fixtures.find_table_name(table_name)
+      end
     end
 
     module ClassMethods
@@ -845,17 +839,17 @@ module ActiveRecord
         self.fixture_class_names = self.fixture_class_names.merge(class_names)
       end
 
-      def fixtures(*table_names)
-        if table_names.first == :all
-          table_names = Dir["#{fixture_path}/**/*.{yml,csv}"]
-          table_names.map! { |f| f[(fixture_path.size + 1)..-5] }
+      def fixtures(*fixture_names)
+        if fixture_names.first == :all
+          fixture_names = Dir["#{fixture_path}/**/*.{yml,csv}"]
+          fixture_names.map! { |f| f[(fixture_path.size + 1)..-5] }
         else
-          table_names = table_names.flatten.map { |n| n.to_s }
+          fixture_names = fixture_names.flatten.map { |n| n.to_s }
         end
 
-        self.fixture_table_names |= table_names
-        require_fixture_classes(table_names)
-        setup_fixture_accessors(table_names)
+        self.fixture_table_names |= fixture_names
+        require_fixture_classes(fixture_names)
+        setup_fixture_accessors(fixture_names)
       end
 
       def try_to_load_dependency(file_name)
@@ -870,38 +864,43 @@ module ActiveRecord
         end
       end
 
-      def require_fixture_classes(table_names = nil)
-        (table_names || fixture_table_names).each do |table_name|
-          file_name = table_name.to_s
+      def require_fixture_classes(fixture_names = nil)
+        (fixture_names || fixture_table_names).each do |fixture_name|
+          file_name = fixture_name.to_s
           file_name = file_name.singularize if ActiveRecord::Base.pluralize_table_names
           try_to_load_dependency(file_name)
         end
       end
 
-      def setup_fixture_accessors(table_names = nil)
-        table_names = Array.wrap(table_names || fixture_table_names)
-        table_names.each do |table_name|
-          table_name = table_name.to_s.tr('./', '_')
+      def setup_fixture_accessors(fixture_names = nil)
+        fixture_names = Array.wrap(fixture_names || fixture_table_names)
+        methods = Module.new do
+          fixture_names.each do |fixture_name|
+            fixture_name = fixture_name.to_s.tr('./', '_')
 
-          redefine_method(table_name) do |*fixtures|
-            force_reload = fixtures.pop if fixtures.last == true || fixtures.last == :reload
+            define_method(fixture_name) do |*fixtures|
+              force_reload = fixtures.pop if fixtures.last == true || fixtures.last == :reload
 
-            @fixture_cache[table_name] ||= {}
+              @fixture_cache[fixture_name] ||= {}
 
-            instances = fixtures.map do |fixture|
-              @fixture_cache[table_name].delete(fixture) if force_reload
+              instances = fixtures.map do |fixture|
+                @fixture_cache[fixture_name].delete(fixture) if force_reload
 
-              if @loaded_fixtures[table_name][fixture.to_s]
-                @fixture_cache[table_name][fixture] ||= @loaded_fixtures[table_name][fixture.to_s].find
-              else
-                raise StandardError, "No fixture with name '#{fixture}' found for table '#{table_name}'"
+                if @loaded_fixtures[fixture_name][fixture.to_s]
+                  ActiveRecord::IdentityMap.without do
+                    @fixture_cache[fixture_name][fixture] ||= @loaded_fixtures[fixture_name][fixture.to_s].find
+                  end
+                else
+                  raise StandardError, "No fixture with name '#{fixture}' found for table '#{fixture_name}'"
+                end
               end
-            end
 
-            instances.size == 1 ? instances.first : instances
+              instances.size == 1 ? instances.first : instances
+            end
+            private fixture_name
           end
-          private table_name
         end
+        include methods
       end
 
       def uses_transaction(*methods)
@@ -921,7 +920,7 @@ module ActiveRecord
     end
 
     def setup_fixtures
-      return unless defined?(ActiveRecord) && !ActiveRecord::Base.configurations.blank?
+      return unless !ActiveRecord::Base.configurations.blank?
 
       if pre_loaded_fixtures && !use_transactional_fixtures
         raise RuntimeError, 'pre_loaded_fixtures requires use_transactional_fixtures'
@@ -935,7 +934,7 @@ module ActiveRecord
         if @@already_loaded_fixtures[self.class]
           @loaded_fixtures = @@already_loaded_fixtures[self.class]
         else
-          load_fixtures
+          @loaded_fixtures = load_fixtures
           @@already_loaded_fixtures[self.class] = @loaded_fixtures
         end
         ActiveRecord::Base.connection.increment_open_transactions
@@ -945,7 +944,7 @@ module ActiveRecord
       else
         Fixtures.reset_cache
         @@already_loaded_fixtures[self.class] = nil
-        load_fixtures
+        @loaded_fixtures = load_fixtures
       end
 
       # Instantiate fixtures for every test if requested.
@@ -969,15 +968,8 @@ module ActiveRecord
 
     private
       def load_fixtures
-        @loaded_fixtures = {}
         fixtures = Fixtures.create_fixtures(fixture_path, fixture_table_names, fixture_class_names)
-        unless fixtures.nil?
-          if fixtures.instance_of?(Fixtures)
-            @loaded_fixtures[fixtures.name] = fixtures
-          else
-            fixtures.each { |f| @loaded_fixtures[f.name] = f }
-          end
-        end
+        Hash[fixtures.map { |f| [f.name, f] }]
       end
 
       # for pre_loaded_fixtures, only require the classes once. huge speed improvement
@@ -993,8 +985,8 @@ module ActiveRecord
           Fixtures.instantiate_all_loaded_fixtures(self, load_instances?)
         else
           raise RuntimeError, 'Load fixtures before instantiating them.' if @loaded_fixtures.nil?
-          @loaded_fixtures.each do |table_name, fixtures|
-            Fixtures.instantiate_fixtures(self, table_name, fixtures, load_instances?)
+          @loaded_fixtures.each do |fixture_name, fixtures|
+            Fixtures.instantiate_fixtures(self, fixture_name, fixtures, load_instances?)
           end
         end
       end
diff --git a/activerecord/lib/active_record/identity_map.rb b/activerecord/lib/active_record/identity_map.rb
new file mode 100644
index 0000000000..d18b2b0a54
--- /dev/null
+++ b/activerecord/lib/active_record/identity_map.rb
@@ -0,0 +1,102 @@
+module ActiveRecord
+  # = Active Record Identity Map
+  #
+  # Ensures that each object gets loaded only once by keeping every loaded
+  # object in a map. Looks up objects using the map when referring to them.
+  #
+  # More information on Identity Map pattern:
+  #   http://www.martinfowler.com/eaaCatalog/identityMap.html
+  #
+  # == Configuration
+  #
+  # In order to enable IdentityMap, set <tt>config.active_record.identity_map = true</tt>
+  # in your <tt>config/application.rb</tt> file.
+  #
+  # IdentityMap is disabled by default.
+  #
+  module IdentityMap
+    extend ActiveSupport::Concern
+
+    class << self
+      def enabled=(flag)
+        Thread.current[:identity_map_enabled] = flag
+      end
+
+      def enabled
+        Thread.current[:identity_map_enabled]
+      end
+      alias enabled? enabled
+
+      def repository
+        Thread.current[:identity_map] ||= Hash.new { |h,k| h[k] = {} }
+      end
+
+      def use
+        old, self.enabled = enabled, true
+
+        yield if block_given?
+      ensure
+        self.enabled = old
+        clear
+      end
+
+      def without
+        old, self.enabled = enabled, false
+
+        yield if block_given?
+      ensure
+        self.enabled = old
+      end
+
+      def get(klass, primary_key)
+        obj = repository[klass.symbolized_base_class][primary_key]
+        obj.is_a?(klass) ? obj : nil
+      end
+
+      def add(record)
+        repository[record.class.symbolized_base_class][record.id] = record
+      end
+
+      def remove(record)
+        repository[record.class.symbolized_base_class].delete(record.id)
+      end
+
+      def remove_by_id(symbolized_base_class, id)
+        repository[symbolized_base_class].delete(id)
+      end
+
+      def clear
+        repository.clear
+      end
+    end
+
+    # Reinitialize an Identity Map model object from +coder+.
+    # +coder+ must contain the attributes necessary for initializing an empty
+    # model object.
+    def reinit_with(coder)
+      @attributes_cache = {}
+      dirty = @changed_attributes.keys
+      @attributes.update(coder['attributes'].except(*dirty))
+      @changed_attributes.update(coder['attributes'].slice(*dirty))
+      @changed_attributes.delete_if{|k,v| v.eql? @attributes[k]}
+
+      set_serialized_attributes
+
+      run_callbacks :find
+
+      self
+    end
+
+    class Middleware
+      def initialize(app)
+        @app = app
+      end
+
+      def call(env)
+        ActiveRecord::IdentityMap.use do
+          @app.call(env)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index e5065de7fb..6b2b1ebafe 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -58,6 +58,12 @@ module ActiveRecord
       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 attributes_from_column_definition
           result = super
 
@@ -78,8 +84,8 @@ module ActiveRecord
           return 0 if attribute_names.empty?
 
           lock_col = self.class.locking_column
-          previous_value = send(lock_col).to_i
-          send(lock_col + '=', previous_value + 1)
+          previous_lock_value = send(lock_col).to_i
+          increment_lock
 
           attribute_names += [lock_col]
           attribute_names.uniq!
@@ -89,7 +95,7 @@ module ActiveRecord
 
             stmt = relation.where(
               relation.table[self.class.primary_key].eq(quoted_id).and(
-                relation.table[lock_col].eq(quote_value(previous_value))
+                relation.table[lock_col].eq(quote_value(previous_lock_value))
               )
             ).arel.compile_update(arel_attributes_values(false, false, attribute_names))
 
@@ -103,7 +109,7 @@ module ActiveRecord
 
           # If something went wrong, revert the version.
           rescue Exception
-            send(lock_col + '=', previous_value)
+            send(lock_col + '=', previous_lock_value)
             raise
           end
         end
diff --git a/activerecord/lib/active_record/locking/pessimistic.rb b/activerecord/lib/active_record/locking/pessimistic.rb
index d900831e13..557b277d6b 100644
--- a/activerecord/lib/active_record/locking/pessimistic.rb
+++ b/activerecord/lib/active_record/locking/pessimistic.rb
@@ -40,7 +40,7 @@ module ActiveRecord
     #
     # 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/8.1/interactive/sql-select.html#SQL-FOR-UPDATE-SHARE
+    #   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
diff --git a/activerecord/lib/active_record/log_subscriber.rb b/activerecord/lib/active_record/log_subscriber.rb
index c7ae12977a..afadbf03ef 100644
--- a/activerecord/lib/active_record/log_subscriber.rb
+++ b/activerecord/lib/active_record/log_subscriber.rb
@@ -22,8 +22,16 @@ module ActiveRecord
       self.class.runtime += event.duration
       return unless logger.debug?
 
-      name = '%s (%.1fms)' % [event.payload[:name], event.duration]
-      sql  = event.payload[:sql].squeeze(' ')
+      payload = event.payload
+      name    = '%s (%.1fms)' % [payload[:name], event.duration]
+      sql     = payload[:sql].squeeze(' ')
+      binds   = nil
+
+      unless (payload[:binds] || []).empty?
+        binds = "  " + payload[:binds].map { |col,v|
+          [col.name, v]
+        }.inspect
+      end
 
       if odd?
         name = color(name, CYAN, true)
@@ -32,7 +40,7 @@ module ActiveRecord
         name = color(name, MAGENTA, true)
       end
 
-      debug "  #{name}  #{sql}"
+      debug "  #{name}  #{sql}#{binds}"
     end
 
     def odd?
@@ -45,4 +53,4 @@ module ActiveRecord
   end
 end
 
-ActiveRecord::LogSubscriber.attach_to :active_record
\ No newline at end of file
+ActiveRecord::LogSubscriber.attach_to :active_record
diff --git a/activerecord/lib/active_record/migration/command_recorder.rb b/activerecord/lib/active_record/migration/command_recorder.rb
index d7e481905a..c9d57ce812 100644
--- a/activerecord/lib/active_record/migration/command_recorder.rb
+++ b/activerecord/lib/active_record/migration/command_recorder.rb
@@ -40,7 +40,7 @@ module ActiveRecord
         @commands.reverse.map { |name, args|
           method = :"invert_#{name}"
           raise IrreversibleMigration unless respond_to?(method, true)
-          __send__(method, args)
+          send(method, args)
         }
       end
 
@@ -48,12 +48,16 @@ module ActiveRecord
         super || delegate.respond_to?(*args)
       end
 
-      def send(method, *args) # :nodoc:
-        return super unless respond_to?(method)
-        record(method, args)
+      [:create_table, :rename_table, :add_column, :remove_column, :rename_index, :rename_column, :add_index, :remove_index, :add_timestamps, :remove_timestamps, :change_column, :change_column_default].each do |method|
+        class_eval <<-EOV, __FILE__, __LINE__ + 1
+          def #{method}(*args)
+            record(:"#{method}", args)
+          end
+        EOV
       end
 
       private
+
       def invert_create_table(args)
         [:drop_table, args]
       end
@@ -86,6 +90,14 @@ module ActiveRecord
       def invert_add_timestamps(args)
         [:remove_timestamps, args]
       end
+
+      # Forwards any missing method call to the \target.
+      def method_missing(method, *args, &block)
+        @delegate.send(method, *args, &block)
+      rescue NoMethodError => e
+        raise e, e.message.sub(/ for #<.*$/, " via proxy for #{@delegate}")
+      end
+
     end
   end
 end
diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb
index 0f421560f0..d291632260 100644
--- a/activerecord/lib/active_record/named_scope.rb
+++ b/activerecord/lib/active_record/named_scope.rb
@@ -102,10 +102,9 @@ module ActiveRecord
       def scope(name, scope_options = {})
         name = name.to_sym
         valid_scope_name?(name)
-
         extension = Module.new(&Proc.new) if block_given?
 
-        scopes[name] = lambda do |*args|
+        scope_proc = lambda do |*args|
           options = scope_options.respond_to?(:call) ? scope_options.call(*args) : scope_options
 
           relation = if options.is_a?(Hash)
@@ -119,6 +118,8 @@ module ActiveRecord
           extension ? relation.extending(extension) : relation
         end
 
+        self.scopes = self.scopes.merge name => scope_proc
+
         singleton_class.send(:redefine_method, name, &scopes[name])
       end
 
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index 050b521b6a..522c0cfc9f 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -387,13 +387,13 @@ module ActiveRecord
         end
       end
 
-      association = send(association_name)
+      association = association(association_name)
 
       existing_records = if association.loaded?
-        association.to_a
+        association.target
       else
         attribute_ids = attributes_collection.map {|a| a['id'] || a[:id] }.compact
-        attribute_ids.empty? ? [] : association.all(:conditions => {association.primary_key => attribute_ids})
+        attribute_ids.empty? ? [] : association.scoped.where(association.klass.primary_key => attribute_ids)
       end
 
       attributes_collection.each do |attributes|
@@ -403,11 +403,29 @@ module ActiveRecord
           unless reject_new_record?(association_name, attributes)
             association.build(attributes.except(*UNASSIGNABLE_KEYS))
           end
-
+        elsif existing_records.count == 0 #Existing record but not yet associated
+          existing_record = self.class.reflect_on_association(association_name).klass.find(attributes['id'])
+          if !call_reject_if(association_name, attributes)
+            association.send(:add_record_to_target_with_callbacks, existing_record) if !association.loaded?
+            assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy])
+          end
         elsif existing_record = existing_records.detect { |record| record.id.to_s == attributes['id'].to_s }
-          association.send(:add_record_to_target_with_callbacks, existing_record) if !association.loaded? && !call_reject_if(association_name, attributes)
-          assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy])
+          unless association.loaded? || 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)
+            target_record = association.target.detect { |record| record == existing_record }
+
+            if target_record
+              existing_record = target_record
+            else
+              association.add_to_target(existing_record)
+            end
 
+          end
+
+          if !call_reject_if(association_name, attributes)
+            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
diff --git a/activerecord/lib/active_record/observer.rb b/activerecord/lib/active_record/observer.rb
index 8b011ad9af..0893d7e337 100644
--- a/activerecord/lib/active_record/observer.rb
+++ b/activerecord/lib/active_record/observer.rb
@@ -104,10 +104,17 @@ module ActiveRecord
 
       def define_callbacks(klass)
         observer = self
+        observer_name = observer.class.name.underscore.gsub('/', '__')
 
         ActiveRecord::Callbacks::CALLBACKS.each do |callback|
           next unless respond_to?(callback)
-          klass.send(callback){|record| observer.send(callback, record)}
+          callback_meth = :"_notify_#{observer_name}_for_#{callback}"
+          unless klass.respond_to?(callback_meth)
+            klass.send(:define_method, callback_meth) do
+              observer.send(callback, self)
+            end
+            klass.send(callback, callback_meth)
+          end
         end
       end
   end
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 9ac8fcb176..df7b22080c 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -64,7 +64,10 @@ module ActiveRecord
     # callbacks, Observer methods, or any <tt>:dependent</tt> association
     # options, use <tt>#destroy</tt>.
     def delete
-      self.class.delete(id) if persisted?
+      if persisted?
+        self.class.delete(id)
+        IdentityMap.remove(self) if IdentityMap.enabled?
+      end
       @destroyed = true
       freeze
     end
@@ -73,6 +76,7 @@ module ActiveRecord
     # that no changes should be made (since they can't be persisted).
     def destroy
       if persisted?
+        IdentityMap.remove(self) if IdentityMap.enabled?
         self.class.unscoped.where(self.class.arel_table[self.class.primary_key].eq(id)).delete_all
       end
 
@@ -196,7 +200,12 @@ module ActiveRecord
     def reload(options = nil)
       clear_aggregation_cache
       clear_association_cache
-      @attributes.update(self.class.unscoped { self.class.find(self.id, options) }.instance_variable_get('@attributes'))
+
+      IdentityMap.without do
+        fresh_object = self.class.unscoped { self.class.find(self.id, options) }
+        @attributes.update(fresh_object.instance_variable_get('@attributes'))
+      end
+
       @attributes_cache = {}
       self
     end
@@ -224,6 +233,7 @@ module ActiveRecord
     def touch(name = nil)
       attributes = timestamp_attributes_for_update_in_model
       attributes << name if name
+
       unless attributes.empty?
         current_time = current_time_from_proper_timezone
         changes = {}
@@ -232,6 +242,8 @@ module ActiveRecord
           changes[column.to_s] = write_attribute(column.to_s, 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.update_all(changes, { primary_key => self[primary_key] }) == 1
@@ -258,11 +270,11 @@ module ActiveRecord
     # Creates a record with values matching those of the instance attributes
     # and returns its id.
     def create
-      if self.id.nil? && connection.prefetch_primary_key?(self.class.table_name)
+      if id.nil? && connection.prefetch_primary_key?(self.class.table_name)
         self.id = connection.next_sequence_value(self.class.sequence_name)
       end
 
-      attributes_values = arel_attributes_values
+      attributes_values = arel_attributes_values(!id.nil?)
 
       new_id = if attributes_values.empty?
         self.class.unscoped.insert connection.empty_insert_statement_value
@@ -272,6 +284,7 @@ module ActiveRecord
 
       self.id ||= new_id
 
+      IdentityMap.add(self) if IdentityMap.enabled?
       @new_record = false
       id
     end
@@ -282,7 +295,7 @@ module ActiveRecord
     # that instances loaded from the database would.
     def attributes_from_column_definition
       Hash[self.class.columns.map do |column|
-        [column.name, column.default] unless column.name == self.class.primary_key
+        [column.name, column.default]
       end]
     end
   end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index dfe255ad7c..cace6f0cc0 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -43,6 +43,11 @@ module ActiveRecord
       ActiveSupport.on_load(:active_record) { self.logger ||= ::Rails.logger }
     end
 
+    initializer "active_record.identity_map" do |app|
+      config.app_middleware.insert_after "::ActionDispatch::Callbacks",
+        "ActiveRecord::IdentityMap::Middleware" if config.active_record.delete(:identity_map)
+    end
+
     initializer "active_record.set_configs" do |app|
       ActiveSupport.on_load(:active_record) do
         app.config.active_record.each do |k,v|
@@ -69,11 +74,10 @@ module ActiveRecord
     end
 
     initializer "active_record.set_dispatch_hooks", :before => :set_clear_dependencies_hook do |app|
-      unless app.config.cache_classes
-        ActiveSupport.on_load(:active_record) do
-          ActionDispatch::Callbacks.after do
-            ActiveRecord::Base.clear_reloadable_connections!
-          end
+      ActiveSupport.on_load(:active_record) do
+        ActionDispatch::Reloader.to_cleanup do
+          ActiveRecord::Base.clear_reloadable_connections!
+          ActiveRecord::Base.clear_cache!
         end
       end
     end
@@ -82,7 +86,7 @@ module ActiveRecord
       ActiveSupport.on_load(:active_record) do
         instantiate_observers
 
-        ActionDispatch::Callbacks.to_prepare(:activerecord_instantiate_observers) do
+        ActionDispatch::Reloader.to_prepare do
           ActiveRecord::Base.instantiate_observers
         end
       end
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index a4fc18148e..ff36814684 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -193,7 +193,7 @@ db_namespace = namespace :db do
       file_list = []
       Dir.foreach(File.join(Rails.root, 'db', 'migrate')) do |file|
         # only files matching "20091231235959_some_name.rb" pattern
-        if match_data = /(\d{14})_(.+)\.rb/.match(file)
+        if match_data = /^(\d{14})_(.+)\.rb$/.match(file)
           status = db_list.delete(match_data[1]) ? 'up' : 'down'
           file_list << [status, match_data[1], match_data[2]]
         end
@@ -296,8 +296,8 @@ db_namespace = namespace :db do
       base_dir = ENV['FIXTURES_PATH'] ? File.join(Rails.root, ENV['FIXTURES_PATH']) : File.join(Rails.root, 'test', 'fixtures')
       fixtures_dir = ENV['FIXTURES_DIR'] ? File.join(base_dir, ENV['FIXTURES_DIR']) : base_dir
 
-      (ENV['FIXTURES'] ? ENV['FIXTURES'].split(/,/).map {|f| File.join(fixtures_dir, f) } : Dir["#{fixtures_dir}/**/*.{yml,csv}"]).each do |fixture_file|
-        Fixtures.create_fixtures(fixtures_dir, fixture_file[(fixtures_dir.size + 1)..-5])
+      (ENV['FIXTURES'] ? ENV['FIXTURES'].split(/,/) : Dir["#{fixtures_dir}/**/*.{yml,csv}"].map {|f| f[(fixtures_dir.size + 1)..-5] }).each do |fixture_file|
+        Fixtures.create_fixtures(fixtures_dir, fixture_file)
       end
     end
 
@@ -409,7 +409,7 @@ db_namespace = namespace :db do
         ENV['PGHOST']     = abcs["test"]["host"] if abcs["test"]["host"]
         ENV['PGPORT']     = abcs["test"]["port"].to_s if abcs["test"]["port"]
         ENV['PGPASSWORD'] = abcs["test"]["password"].to_s if abcs["test"]["password"]
-        `psql -U "#{abcs["test"]["username"]}" -f #{Rails.root}/db/#{Rails.env}_structure.sql #{abcs["test"]["database"]}`
+        `psql -U "#{abcs["test"]["username"]}" -f #{Rails.root}/db/#{Rails.env}_structure.sql #{abcs["test"]["database"]} #{abcs["test"]["template"]}`
       when "sqlite", "sqlite3"
         dbfile = abcs["test"]["database"] || abcs["test"]["dbfile"]
         `#{abcs["test"]["adapter"]} #{dbfile} < #{Rails.root}/db/#{Rails.env}_structure.sql`
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 0ec8da0088..e3e2cac042 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -1,4 +1,5 @@
 require 'active_support/core_ext/class/attribute'
+require 'active_support/core_ext/module/deprecation'
 
 module ActiveRecord
   # = Active Record Reflection
@@ -196,8 +197,21 @@ module ActiveRecord
         @quoted_table_name ||= klass.quoted_table_name
       end
 
+      def foreign_key
+        @foreign_key ||= options[:foreign_key] || derive_foreign_key
+      end
+
       def primary_key_name
-        @primary_key_name ||= options[:foreign_key] || derive_primary_key_name
+        foreign_key
+      end
+      deprecate :primary_key_name => :foreign_key
+
+      def foreign_type
+        @foreign_type ||= options[:foreign_type] || "#{name}_type"
+      end
+
+      def type
+        @type ||= "#{options[:as]}_type"
       end
 
       def primary_key_column
@@ -205,15 +219,18 @@ module ActiveRecord
       end
 
       def association_foreign_key
-        @association_foreign_key ||= @options[:association_foreign_key] || class_name.foreign_key
+        @association_foreign_key ||= options[:association_foreign_key] || class_name.foreign_key
       end
 
       def association_primary_key
-        @association_primary_key ||= @options[:primary_key] || klass.primary_key
+        @association_primary_key ||=
+          options[:primary_key] ||
+          !options[:polymorphic] && klass.primary_key ||
+          'id'
       end
 
       def active_record_primary_key
-        @active_record_primary_key ||= @options[:primary_key] || active_record.primary_key
+        @active_record_primary_key ||= options[:primary_key] || active_record.primary_key
       end
 
       def counter_cache_column
@@ -300,22 +317,36 @@ module ActiveRecord
         !options[:validate].nil? ? options[:validate] : (options[:autosave] == true || macro == :has_many)
       end
 
-      def dependent_conditions(record, base_class, extra_conditions)
-        dependent_conditions = []
-        dependent_conditions << "#{primary_key_name} = #{record.send(name).send(:owner_quoted_id)}"
-        dependent_conditions << "#{options[:as]}_type = '#{base_class.name}'" if options[:as]
-        dependent_conditions << klass.send(:sanitize_sql, options[:conditions]) if options[:conditions]
-        dependent_conditions << extra_conditions if extra_conditions
-        dependent_conditions = dependent_conditions.collect {|where| "(#{where})" }.join(" AND ")
-        dependent_conditions = dependent_conditions.gsub('@', '\@')
-        dependent_conditions
-      end
-
       # Returns +true+ if +self+ is a +belongs_to+ reflection.
       def belongs_to?
         macro == :belongs_to
       end
 
+      def association_class
+        case macro
+        when :belongs_to
+          if options[:polymorphic]
+            Associations::BelongsToPolymorphicAssociation
+          else
+            Associations::BelongsToAssociation
+          end
+        when :has_and_belongs_to_many
+          Associations::HasAndBelongsToManyAssociation
+        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
+
       private
         def derive_class_name
           class_name = name.to_s.camelize
@@ -323,7 +354,7 @@ module ActiveRecord
           class_name
         end
 
-        def derive_primary_key_name
+        def derive_foreign_key
           if belongs_to?
             "#{name}_id"
           elsif options[:as]
@@ -337,7 +368,7 @@ module ActiveRecord
     # Holds all the meta-data about a :through association as it was specified
     # in the Active Record class.
     class ThroughReflection < AssociationReflection #:nodoc:
-      delegate :primary_key_name, :association_foreign_key, :to => :source_reflection
+      delegate :foreign_key, :foreign_type, :association_foreign_key, :to => :source_reflection
 
       # Gets the source of the through reflection.  It checks both a singularized
       # and pluralized form for <tt>:belongs_to</tt> or <tt>:has_many</tt>.
@@ -469,11 +500,23 @@ module ActiveRecord
         @source_reflection_names ||= (options[:source] ? [options[:source]] : [name.to_s.singularize, name]).collect { |n| n.to_sym }
       end
 
+      def source_options
+        source_reflection.options
+      end
+
+      def through_options
+        through_reflection.options
+      end
+
       def check_validity!
         if through_reflection.nil?
           raise HasManyThroughAssociationNotFoundError.new(active_record.name, self)
         end
 
+        if through_reflection.options[:polymorphic]
+          raise HasManyThroughAssociationPolymorphicThroughError.new(active_record.name, self)
+        end
+
         if source_reflection.nil?
           raise HasManyThroughSourceAssociationNotFoundError.new(self)
         end
@@ -483,7 +526,11 @@ module ActiveRecord
         end
 
         if source_reflection.options[:polymorphic] && options[:source_type].nil?
-          raise HasManyThroughAssociationPolymorphicError.new(active_record.name, self, source_reflection)
+          raise HasManyThroughAssociationPolymorphicSourceError.new(active_record.name, self, source_reflection)
+        end
+
+        if macro == :has_one && through_reflection.collection?
+          raise HasOneThroughCantAssociateThroughCollection.new(active_record.name, self, through_reflection)
         end
 
         check_validity_of_inverse!
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 3009bb70c1..f939bedc81 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -10,8 +10,9 @@ module ActiveRecord
 
     include FinderMethods, Calculations, SpawnMethods, QueryMethods, Batches
 
+    # These are explicitly delegated to improve performance (avoids method_missing)
     delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to => :to_a
-    delegate :insert, :to => :arel
+    delegate :table_name, :primary_key, :to => :klass
 
     attr_reader :table, :klass, :loaded
     attr_accessor :extensions
@@ -28,6 +29,25 @@ module ActiveRecord
       @extensions = []
     end
 
+    def insert(values)
+      im = arel.compile_insert values
+      im.into @table
+
+      primary_key_value = nil
+
+      if primary_key && Hash === values
+        primary_key_value = values[values.keys.find { |k|
+          k.name == primary_key
+        }]
+      end
+
+      @klass.connection.insert(
+        im.to_sql,
+        'SQL',
+        primary_key,
+        primary_key_value)
+    end
+
     def new(*args, &block)
       scoping { @klass.new(*args, &block) }
     end
@@ -47,25 +67,28 @@ module ActiveRecord
     end
 
     def respond_to?(method, include_private = false)
-      return true if arel.respond_to?(method, include_private) || Array.method_defined?(method) || @klass.respond_to?(method, include_private)
-
-      if match = DynamicFinderMatch.match(method)
-        return true if @klass.send(:all_attributes_exists?, match.attribute_names)
-      elsif match = DynamicScopeMatch.match(method)
-        return true if @klass.send(:all_attributes_exists?, match.attribute_names)
-      else
+      arel.respond_to?(method, include_private)     ||
+        Array.method_defined?(method)               ||
+        @klass.respond_to?(method, include_private) ||
         super
-      end
     end
 
     def to_a
       return @records if loaded?
 
-      @records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel.to_sql, @bind_values)
+      @records = if @readonly_value.nil? && !@klass.locking_enabled?
+        eager_loading? ? find_with_associations : @klass.find_by_sql(arel.to_sql, @bind_values)
+      else
+        IdentityMap.without do
+          eager_loading? ? find_with_associations : @klass.find_by_sql(arel.to_sql, @bind_values)
+        end
+      end
 
       preload = @preload_values
       preload +=  @includes_values unless eager_loading?
-      preload.each {|associations| @klass.send(:preload_associations, @records, associations) }
+      preload.each do |associations|
+        ActiveRecord::Associations::Preloader.new(@records, associations).run
+      end
 
       # @readonly_value is true only if set explicitly. @implicit_readonly is true if there
       # are JOINS and no explicit SELECT.
@@ -150,17 +173,29 @@ module ActiveRecord
     #
     #   # Update all books that match conditions, but limit it to 5 ordered by date
     #   Book.update_all "author = 'David'", "title LIKE '%Rails%'", :order => 'created_at', :limit => 5
+    #
+    #   # Conditions from the current relation also works
+    #   Book.where('title LIKE ?', '%Rails%').update_all(:author => 'David')
+    #
+    #   # The same idea applies to limit and order
+    #   Book.where('title LIKE ?', '%Rails%').order(:created_at).limit(5).update_all(:author => 'David')
     def update_all(updates, conditions = nil, options = {})
       if conditions || options.present?
         where(conditions).apply_finder_options(options.slice(:limit, :order)).update_all(updates)
       else
+        limit = nil
+        order = []
         # Apply limit and order only if they're both present
         if @limit_value.present? == @order_values.present?
-          stmt = arel.compile_update(Arel::SqlLiteral.new(@klass.send(:sanitize_sql_for_assignment, updates)))
-          @klass.connection.update stmt.to_sql
-        else
-          except(:limit, :order).update_all(updates)
+          limit = arel.limit
+          order = arel.orders
         end
+
+        stmt = arel.compile_update(Arel.sql(@klass.send(:sanitize_sql_for_assignment, updates)))
+        stmt.take limit if limit
+        stmt.order(*order)
+        stmt.key = table[primary_key]
+        @klass.connection.update stmt.to_sql
       end
     end
 
@@ -217,6 +252,7 @@ module ActiveRecord
     #
     #   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
@@ -266,6 +302,7 @@ module ActiveRecord
     #
     #   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
@@ -302,7 +339,7 @@ module ActiveRecord
     #   # Delete multiple rows
     #   Todo.delete([2,3,4])
     def delete(id_or_array)
-      where(@klass.primary_key => id_or_array).delete_all
+      where(primary_key => id_or_array).delete_all
     end
 
     def reload
@@ -318,10 +355,6 @@ module ActiveRecord
       self
     end
 
-    def primary_key
-      @primary_key ||= table[@klass.primary_key]
-    end
-
     def to_sql
       @to_sql ||= arel.to_sql
     end
@@ -355,10 +388,6 @@ module ActiveRecord
       to_a.inspect
     end
 
-    def table_name
-      @klass.table_name
-    end
-
     protected
 
     def method_missing(method, *args, &block)
diff --git a/activerecord/lib/active_record/relation/batches.rb b/activerecord/lib/active_record/relation/batches.rb
index b41e935ed5..bf5a60f458 100644
--- a/activerecord/lib/active_record/relation/batches.rb
+++ b/activerecord/lib/active_record/relation/batches.rb
@@ -39,7 +39,7 @@ module ActiveRecord
     # ascending on the primary key ("id ASC") to make the batch ordering
     # work. This also mean that this method only works with integer-based
     # primary keys. You can't set the limit either, that's used to control
-    # the the batch sizes.
+    # the batch sizes.
     #
     # Example:
     #
@@ -65,7 +65,7 @@ module ActiveRecord
       batch_size = options.delete(:batch_size) || 1000
 
       relation = relation.except(:order).order(batch_order).limit(batch_size)
-      records = relation.where(primary_key.gteq(start)).all
+      records = relation.where(table[primary_key].gteq(start)).all
 
       while records.any?
         yield records
@@ -73,7 +73,7 @@ module ActiveRecord
         break if records.size < batch_size
 
         if primary_key_offset = records.last.id
-          records = relation.where(primary_key.gt(primary_key_offset)).to_a
+          records = relation.where(table[primary_key].gt(primary_key_offset)).to_a
         else
           raise "Primary key not included in the custom select clause"
         end
@@ -83,7 +83,7 @@ module ActiveRecord
     private
 
     def batch_order
-      "#{@klass.table_name}.#{@klass.primary_key} ASC"
+      "#{table_name}.#{primary_key} ASC"
     end
   end
 end
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index fd45bb24dd..c1842b1a96 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -168,7 +168,7 @@ module ActiveRecord
 
         unless arel.ast.grep(Arel::Nodes::OuterJoin).empty?
           distinct = true
-          column_name = @klass.primary_key if column_name == :all
+          column_name = primary_key if column_name == :all
         end
 
         distinct = nil if column_name =~ /\s*DISTINCT\s+/i
@@ -204,14 +204,26 @@ module ActiveRecord
 
       relation.select_values = [select_value]
 
-      type_cast_calculated_value(@klass.connection.select_value(relation.to_sql), column_for(column_name), operation)
+      query_builder = relation.arel
+
+      if operation == "count"
+        limit  = relation.limit_value
+        offset = relation.offset_value
+
+        unless limit && offset
+          query_builder.limit  = nil
+          query_builder.offset = nil
+        end
+      end
+
+      type_cast_calculated_value(@klass.connection.select_value(query_builder.to_sql), column_for(column_name), operation)
     end
 
     def execute_grouped_calculation(operation, column_name, distinct) #:nodoc:
       group_attr      = @group_values
       association     = @klass.reflect_on_association(group_attr.first.to_sym)
       associated      = group_attr.size == 1 && association && association.macro == :belongs_to # only count belongs_to associations
-      group_fields  = Array(associated ? association.primary_key_name : group_attr)
+      group_fields  = Array(associated ? association.foreign_key : group_attr)
       group_aliases = group_fields.map { |field| column_alias_for(field) }
       group_columns = group_aliases.zip(group_fields).map { |aliaz,field|
         [aliaz, column_for(field)]
@@ -282,15 +294,11 @@ module ActiveRecord
     end
 
     def type_cast_calculated_value(value, column, operation = nil)
-      if value.is_a?(String) || value.nil?
-        case operation
-          when 'count'   then value.to_i
-          when 'sum'     then type_cast_using_column(value || '0', column)
-          when 'average' then value.try(:to_d)
-          else type_cast_using_column(value, column)
-        end
-      else
-        type_cast_using_column(value, column)
+      case operation
+        when 'count'   then value.to_i
+        when 'sum'     then type_cast_using_column(value || '0', column)
+        when 'average' then value.respond_to?(:to_d) ? value.to_d : value
+        else type_cast_using_column(value, column)
       end
     end
 
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 906ad7699c..426000fde1 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -19,7 +19,7 @@ module ActiveRecord
     #
     # All approaches accept an options hash as their last parameter.
     #
-    # ==== Parameters
+    # ==== Options
     #
     # * <tt>:conditions</tt> - An SQL fragment like "administrator = 1", <tt>["user_name = ?", username]</tt>,
     #   or <tt>["user_name = :user_name", { :user_name => user_name }]</tt>. See conditions in the intro.
@@ -171,13 +171,13 @@ module ActiveRecord
     def exists?(id = nil)
       id = id.id if ActiveRecord::Base === id
 
-      relation = select(primary_key).limit(1)
+      relation = select("1").limit(1)
 
       case id
       when Array, Hash
         relation = relation.where(id)
       else
-        relation = relation.where(primary_key.eq(id)) if id
+        relation = relation.where(table[primary_key].eq(id)) if id
       end
 
       relation.first ? true : false
@@ -187,8 +187,9 @@ module ActiveRecord
 
     def find_with_associations
       including = (@eager_load_values + @includes_values).uniq
-      join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, including, nil)
-      rows = construct_relation_for_association_find(join_dependency).to_a
+      join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, including, [])
+      relation = construct_relation_for_association_find(join_dependency)
+      rows = connection.select_all(relation.to_sql, 'SQL', relation.bind_values)
       join_dependency.instantiate(rows)
     rescue ThrowResult
       []
@@ -196,7 +197,7 @@ module ActiveRecord
 
     def construct_relation_for_association_calculations
       including = (@eager_load_values + @includes_values).uniq
-      join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, including, arel.froms.first)
+      join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, including, arel.froms.first)
       relation = except(:includes, :eager_load, :preload)
       apply_join_dependency(relation, join_dependency)
     end
@@ -225,10 +226,10 @@ module ActiveRecord
 
     def construct_limited_ids_condition(relation)
       orders = relation.order_values
-      values = @klass.connection.distinct("#{@klass.connection.quote_table_name @klass.table_name}.#{@klass.primary_key}", orders)
+      values = @klass.connection.distinct("#{@klass.connection.quote_table_name table_name}.#{primary_key}", orders)
 
-      ids_array = relation.select(values).collect {|row| row[@klass.primary_key]}
-      ids_array.empty? ? raise(ThrowResult) : primary_key.in(ids_array)
+      ids_array = relation.select(values).collect {|row| row[primary_key]}
+      ids_array.empty? ? raise(ThrowResult) : table[primary_key].in(ids_array)
     end
 
     def find_by_attributes(match, attributes, *args)
@@ -290,24 +291,24 @@ module ActiveRecord
     def find_one(id)
       id = id.id if ActiveRecord::Base === id
 
-      column = columns_hash[primary_key.name.to_s]
+      column = columns_hash[primary_key]
 
       substitute = connection.substitute_for(column, @bind_values)
-      relation = where(primary_key.eq(substitute))
+      relation = where(table[primary_key].eq(substitute))
       relation.bind_values = [[column, id]]
       record = relation.first
 
       unless record
         conditions = arel.where_sql
         conditions = " [#{conditions}]" if conditions
-        raise RecordNotFound, "Couldn't find #{@klass.name} with #{@klass.primary_key}=#{id}#{conditions}"
+        raise RecordNotFound, "Couldn't find #{@klass.name} with #{primary_key}=#{id}#{conditions}"
       end
 
       record
     end
 
     def find_some(ids)
-      result = where(primary_key.in(ids)).all
+      result = where(table[primary_key].in(ids)).all
 
       expected_size =
         if @limit_value && ids.size > @limit_value
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index 70d84619a1..9633fd3d82 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -15,18 +15,21 @@ module ActiveRecord
             table = Arel::Table.new(table_name, :engine => engine)
           end
 
-          attribute = table[column] || Arel::Attribute.new(table, column)
+          attribute = table[column.to_sym]
 
           case value
-          when Array, ActiveRecord::Associations::AssociationCollection, ActiveRecord::Relation
+          when ActiveRecord::Relation
+            value.select_values = [value.klass.arel_table['id']] if value.select_values.empty?
+            attribute.in(value.arel.ast)
+          when Array, ActiveRecord::Associations::CollectionProxy
             values = value.to_a.map { |x|
-              x.respond_to?(:quoted_id) ? x.quoted_id : x
+              x.is_a?(ActiveRecord::Base) ? x.id : x
             }
             attribute.in(values)
           when Range, Arel::Relation
             attribute.in(value)
           when ActiveRecord::Base
-            attribute.eq(Arel.sql(value.quoted_id))
+            attribute.eq(value.id)
           when Class
             # FIXME: I think we need to deprecate this behavior
             attribute.eq(value.name)
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 51a39be065..0c7a9ec56d 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -63,7 +63,7 @@ module ActiveRecord
     end
 
     def joins(*args)
-      return self if args.blank?
+      return self if args.compact.blank?
 
       relation = clone
 
@@ -128,7 +128,7 @@ module ActiveRecord
 
     def create_with(value)
       relation = clone
-      relation.create_with_value = value
+      relation.create_with_value = value && (@create_with_value || {}).merge(value)
       relation
     end
 
@@ -152,7 +152,7 @@ module ActiveRecord
       order_clause = arel.order_clauses
 
       order = order_clause.empty? ?
-        "#{@klass.table_name}.#{@klass.primary_key} DESC" :
+        "#{table_name}.#{primary_key} DESC" :
         reverse_sql_order(order_clause).join(', ')
 
       except(:order).order(Arel.sql(order))
@@ -171,7 +171,7 @@ module ActiveRecord
 
       arel.having(*@having_values.uniq.reject{|h| h.blank?}) unless @having_values.empty?
 
-      arel.take(@limit_value) if @limit_value
+      arel.take(connection.sanitize_limit(@limit_value)) if @limit_value
       arel.skip(@offset_value) if @offset_value
 
       arel.group(*@group_values.uniq.reject{|g| g.blank?}) unless @group_values.empty?
@@ -191,42 +191,25 @@ module ActiveRecord
     def custom_join_ast(table, joins)
       joins = joins.reject { |join| join.blank? }
 
-      return if joins.empty?
+      return [] if joins.empty?
 
       @implicit_readonly = true
 
-      joins.map! do |join|
+      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
-        join
-      end
-
-      head = table.create_string_join(table, joins.shift)
-
-      joins.inject(head) do |ast, join|
-        ast.right = table.create_string_join(ast.right, join)
+        table.create_string_join(join)
       end
-
-      head
     end
 
     def collapse_wheres(arel, wheres)
       equalities = wheres.grep(Arel::Nodes::Equality)
 
-      groups = equalities.group_by do |equality|
-        equality.left
-      end
-
-      groups.each do |_, eqls|
-        test = eqls.inject(eqls.shift) do |memo, expr|
-          memo.or(expr)
-        end
-        arel.where(test)
-      end
+      arel.where(Arel::Nodes::And.new(equalities)) unless equalities.empty?
 
       (wheres - equalities).each do |where|
         where = Arel.sql(where) if String === where
@@ -247,18 +230,40 @@ module ActiveRecord
     end
 
     def build_joins(manager, joins)
-      joins = joins.map {|j| j.respond_to?(:strip) ? j.strip : j}.uniq
-
-      association_joins = joins.find_all do |join|
-        [Hash, Array, Symbol].include?(join.class) && !array_of_strings?(join)
+      buckets = joins.group_by do |join|
+        case join
+        when String
+          'string_join'
+        when Hash, Symbol, Array
+          'association_join'
+        when ActiveRecord::Associations::JoinDependency::JoinAssociation
+          'stashed_join'
+        when Arel::Nodes::Join
+          'join_node'
+        else
+          raise 'unknown class: %s' % join.class.name
+        end
       end
 
-      stashed_association_joins = joins.grep(ActiveRecord::Associations::ClassMethods::JoinDependency::JoinAssociation)
+      association_joins         = buckets['association_join'] || []
+      stashed_association_joins = buckets['stashed_join'] || []
+      join_nodes                = buckets['join_node'] || []
+      string_joins              = (buckets['string_join'] || []).map { |x|
+        x.strip
+      }.uniq
+
+      join_list = custom_join_ast(manager, string_joins)
 
-      non_association_joins = (joins - association_joins - stashed_association_joins)
-      join_ast = custom_join_ast(manager.froms.first, non_association_joins)
+      join_dependency = ActiveRecord::Associations::JoinDependency.new(
+        @klass,
+        association_joins,
+        join_list
+      )
 
-      join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, association_joins, join_ast)
+      # TODO: Necessary?
+      join_nodes.each do |join|
+        join_dependency.alias_tracker.aliased_name_for(join.left.name.downcase)
+      end
 
       join_dependency.graft(*stashed_association_joins)
 
@@ -269,10 +274,9 @@ module ActiveRecord
         association.join_to(manager)
       end
 
-      return manager unless join_ast
+      manager.join_sources.concat join_nodes.uniq
+      manager.join_sources.concat join_list
 
-      join_ast.left = manager.froms.first
-      manager.from join_ast
       manager
     end
 
@@ -281,7 +285,7 @@ module ActiveRecord
         @implicit_readonly = false
         arel.project(*selects)
       else
-        arel.project(Arel.sql(@klass.quoted_table_name + '.*'))
+        arel.project(@klass.arel_table[Arel.star])
       end
     end
 
diff --git a/activerecord/lib/active_record/relation/spawn_methods.rb b/activerecord/lib/active_record/relation/spawn_methods.rb
index 5acf3ec83a..4150e36a9a 100644
--- a/activerecord/lib/active_record/relation/spawn_methods.rb
+++ b/activerecord/lib/active_record/relation/spawn_methods.rb
@@ -46,21 +46,28 @@ module ActiveRecord
 
       merged_relation.where_values = merged_wheres
 
-      (Relation::SINGLE_VALUE_METHODS - [:lock]).each do |method|
+      (Relation::SINGLE_VALUE_METHODS - [:lock, :create_with]).each do |method|
         value = r.send(:"#{method}_value")
         merged_relation.send(:"#{method}_value=", value) unless value.nil?
       end
 
       merged_relation.lock_value = r.lock_value unless merged_relation.lock_value
 
+      merged_relation = merged_relation.create_with(r.create_with_value) if r.create_with_value
+
       # Apply scope extension modules
       merged_relation.send :apply_modules, r.extensions
 
       merged_relation
     end
 
-    alias :& :merge
-
+    # Removes from the query the condition(s) specified in +skips+.
+    #
+    # Example:
+    #
+    #   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)
       result = self.class.new(@klass, table)
 
@@ -75,6 +82,13 @@ module ActiveRecord
       result
     end
 
+    # Removes any condition from the query other than the one(s) specified in +onlies+.
+    #
+    # Example:
+    #
+    #   Post.order('id asc').only(:where)         # discards the order condition
+    #   Post.order('id asc').only(:where, :order) # uses the specified order
+    #
     def only(*onlies)
       result = self.class.new(@klass, table)
 
@@ -98,7 +112,7 @@ module ActiveRecord
 
       options.assert_valid_keys(VALID_FIND_OPTIONS)
       finders = options.dup
-      finders.delete_if { |key, value| value.nil? }
+      finders.delete_if { |key, value| value.nil? && key != :limit }
 
       ([:joins, :select, :group, :order, :having, :limit, :offset, :from, :lock, :readonly] & finders.keys).each do |finder|
         relation = relation.send(finder, finders[finder])
diff --git a/activerecord/lib/active_record/result.rb b/activerecord/lib/active_record/result.rb
index 8deff1478f..0465b21e88 100644
--- a/activerecord/lib/active_record/result.rb
+++ b/activerecord/lib/active_record/result.rb
@@ -20,10 +20,14 @@ module ActiveRecord
       hash_rows.each { |row| yield row }
     end
 
+    def to_hash
+      hash_rows
+    end
+
     private
     def hash_rows
       @hash_rows ||= @rows.map { |row|
-        ActiveSupport::OrderedHash[@columns.zip(row)]
+        Hash[@columns.zip(row)]
       }
     end
   end
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index e30b481fe1..a893c0ad85 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -83,7 +83,7 @@ HEADER
 
           # first dump primary key column
           if @connection.respond_to?(:pk_and_sequence_for)
-            pk, pk_seq = @connection.pk_and_sequence_for(table)
+            pk, _ = @connection.pk_and_sequence_for(table)
           elsif @connection.respond_to?(:primary_key)
             pk = @connection.primary_key(table)
           end
diff --git a/activerecord/lib/active_record/serializers/xml_serializer.rb b/activerecord/lib/active_record/serializers/xml_serializer.rb
index 15abf8bac7..8c4adf7116 100644
--- a/activerecord/lib/active_record/serializers/xml_serializer.rb
+++ b/activerecord/lib/active_record/serializers/xml_serializer.rb
@@ -226,17 +226,17 @@ module ActiveRecord #:nodoc:
 
     class Attribute < ActiveModel::Serializers::Xml::Serializer::Attribute #:nodoc:
       def compute_type
-        type = @serializable.class.serialized_attributes.has_key?(name) ?
-          super : @serializable.class.columns_hash[name].type
+        klass = @serializable.class
+        type = if klass.serialized_attributes.key?(name)
+                 super
+               elsif klass.columns_hash.key?(name)
+                 klass.columns_hash[name].type
+               else
+                 NilClass
+               end
 
-        case type
-        when :text
-          :string
-        when :time
-          :datetime
-        else
-          type
-        end
+        { :text => :string,
+          :time => :datetime }[type] || type
       end
       protected :compute_type
     end
diff --git a/activerecord/lib/active_record/session_store.rb b/activerecord/lib/active_record/session_store.rb
index 3400fd6ade..7e77aefb21 100644
--- a/activerecord/lib/active_record/session_store.rb
+++ b/activerecord/lib/active_record/session_store.rb
@@ -59,10 +59,12 @@ module ActiveRecord
       end
 
       def drop_table!
+        connection_pool.clear_table_cache!(table_name)
         connection.drop_table table_name
       end
 
       def create_table!
+        connection_pool.clear_table_cache!(table_name)
         connection.create_table(table_name) do |t|
           t.string session_id_column, :limit => 255
           t.text data_column_name
diff --git a/activerecord/lib/active_record/test_case.rb b/activerecord/lib/active_record/test_case.rb
index 014a900c71..29efbbcb8c 100644
--- a/activerecord/lib/active_record/test_case.rb
+++ b/activerecord/lib/active_record/test_case.rb
@@ -3,6 +3,16 @@ module ActiveRecord
   #
   # Defines some test assertions to test against SQL queries.
   class TestCase < ActiveSupport::TestCase #:nodoc:
+    setup :cleanup_identity_map
+
+    def setup
+      cleanup_identity_map
+    end
+
+    def cleanup_identity_map
+      ActiveRecord::IdentityMap.clear
+    end
+
     def assert_date_from_db(expected, actual, message = nil)
       # SybaseAdapter doesn't have a separate column type just for dates,
       # so the time is in the string and incorrectly formatted
@@ -16,6 +26,7 @@ module ActiveRecord
     def assert_sql(*patterns_to_match)
       $queries_executed = []
       yield
+      $queries_executed
     ensure
       failed_patterns = []
       patterns_to_match.each do |pattern|
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
index 2ecbd906bd..1511c71ffc 100644
--- a/activerecord/lib/active_record/timestamp.rb
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -9,24 +9,26 @@ module ActiveRecord
   #
   # Timestamping can be turned off by setting:
   #
-  #   <tt>ActiveRecord::Base.record_timestamps = false</tt>
+  #   config.active_record.record_timestamps = false
   #
   # Timestamps are in the local timezone by default but you can use UTC by setting:
   #
-  #   <tt>ActiveRecord::Base.default_timezone = :utc</tt>
+  #   config.active_record.default_timezone = :utc
   #
   # == Time Zone aware attributes
   #
   # By default, ActiveRecord::Base keeps all the datetime columns time zone aware by executing following code.
   #
-  #   ActiveRecord::Base.time_zone_aware_attributes = true
+  #   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 for certain
-  # attributes then you can do following:
+  # 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:
   #
-  #   Topic.skip_time_zone_conversion_for_attributes = [:written_on]
+  #   class Topic < ActiveRecord::Base
+  #     self.skip_time_zone_conversion_for_attributes = [:written_on]
+  #   end
   module Timestamp
     extend ActiveSupport::Concern
 
@@ -66,8 +68,16 @@ module ActiveRecord
       self.record_timestamps && (!partial_updates? || changed? || (attributes.keys & self.class.serialized_attributes.keys).present?)
     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| respond_to?(c) }
+      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 #:nodoc:
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index 443f318067..60d4c256c4 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -251,6 +251,7 @@ module ActiveRecord
       remember_transaction_record_state
       yield
     rescue Exception
+      IdentityMap.remove(self) if IdentityMap.enabled?
       restore_transaction_record_state
       raise
     ensure
@@ -259,7 +260,7 @@ module ActiveRecord
 
     # Call the after_commit callbacks
     def committed! #:nodoc:
-      _run_commit_callbacks
+      run_callbacks :commit
     ensure
       clear_transaction_record_state
     end
@@ -267,7 +268,7 @@ module ActiveRecord
     # Call the after rollback callbacks. The 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_rollback_callbacks
+      run_callbacks :rollback
     ensure
       restore_transaction_record_state(force_restore_state)
     end
@@ -301,8 +302,8 @@ module ActiveRecord
     # 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 ||= {}
+      @_start_transaction_state[:id] = id if has_attribute?(self.class.primary_key)
       unless @_start_transaction_state.include?(:new_record)
-        @_start_transaction_state[:id] = id if has_attribute?(self.class.primary_key)
         @_start_transaction_state[:new_record] = @new_record
       end
       unless @_start_transaction_state.include?(:destroyed)
@@ -325,16 +326,14 @@ module ActiveRecord
         @_start_transaction_state[:level] = (@_start_transaction_state[:level] || 0) - 1
         if @_start_transaction_state[:level] < 1
           restore_state = remove_instance_variable(:@_start_transaction_state)
-          if restore_state
-            @attributes = @attributes.dup if @attributes.frozen?
-            @new_record = restore_state[:new_record]
-            @destroyed  = restore_state[:destroyed]
-            if restore_state[:id]
-              self.id = restore_state[:id]
-            else
-              @attributes.delete(self.class.primary_key)
-              @attributes_cache.delete(self.class.primary_key)
-            end
+          @attributes = @attributes.dup if @attributes.frozen?
+          @new_record = restore_state[:new_record]
+          @destroyed  = restore_state[:destroyed]
+          if restore_state.has_key?(:id)
+            self.id = restore_state[:id]
+          else
+            @attributes.delete(self.class.primary_key)
+            @attributes_cache.delete(self.class.primary_key)
           end
         end
       end
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index f367315b22..d73fce9fd0 100644
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -1,5 +1,5 @@
 module ActiveRecord
-  # = Active Record Validations
+  # = 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.
@@ -18,6 +18,13 @@ module ActiveRecord
     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
@@ -37,7 +44,7 @@ module ActiveRecord
       end
     end
 
-    # The validation process on save can be skipped by passing false. The regular Base#save method is
+    # The validation process on save can be skipped by passing :validate => false. 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
@@ -49,7 +56,14 @@ module ActiveRecord
       perform_validations(options) ? super : raise(RecordInvalid.new(self))
     end
 
-    # Runs all the specified validations and returns true if no errors were added otherwise false.
+    # Runs all the validations within the specified context. Returns true if no errors are found,
+    # false 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 valid?(context = nil)
       context ||= (new_record? ? :create : :update)
       output = super(context)
diff --git a/activerecord/lib/active_record/validations/associated.rb b/activerecord/lib/active_record/validations/associated.rb
index 183acd73b8..3a783aeb00 100644
--- a/activerecord/lib/active_record/validations/associated.rb
+++ b/activerecord/lib/active_record/validations/associated.rb
@@ -33,7 +33,9 @@ module ActiveRecord
       #
       # Configuration options:
       # * <tt>:message</tt> - A custom error message (default is: "is invalid")
-      # * <tt>:on</tt> - Specifies when this validation is active (default is <tt>:save</tt>, other options <tt>:create</tt>, <tt>:update</tt>).
+      # * <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.
diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
index 853808eebf..a96796f9ff 100644
--- a/activerecord/lib/active_record/validations/uniqueness.rb
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -15,8 +15,10 @@ module ActiveRecord
       def validate_each(record, attribute, value)
         finder_class = find_finder_class_for(record)
 
-        if value && record.class.serialized_attributes.key?(attribute.to_s)
-          value = YAML.dump value
+        coder = record.class.serialized_attributes[attribute.to_s]
+
+        if value && coder
+          value = coder.dump value
         end
 
         sql, params = mount_sql_and_params(finder_class, record.class.quoted_table_name, attribute, value)
@@ -85,11 +87,16 @@ module ActiveRecord
       # can be named "davidhh".
       #
       #   class Person < ActiveRecord::Base
-      #     validates_uniqueness_of :user_name, :scope => :account_id
+      #     validates_uniqueness_of :user_name
       #   end
       #
-      # It can also validate whether the value of the specified attributes are unique based on multiple
-      # scope parameters.  For example, making sure that a teacher can only be on the schedule once
+      # It can also validate whether the value of the specified attributes are unique based on a scope 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
diff --git a/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb b/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
index 126b6f434b..ce8d7eed42 100644
--- a/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
+++ b/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
@@ -1,4 +1,11 @@
 class <%= migration_class_name %> < ActiveRecord::Migration
+<%- if migration_action == 'add' -%>
+  def change
+<% attributes.each do |attribute| -%>
+    add_column :<%= table_name %>, :<%= attribute.name %>, :<%= attribute.type %>
+<%- end -%>
+  end
+<%- else -%>
   def up
 <% attributes.each do |attribute| -%>
   <%- if migration_action -%>
@@ -14,4 +21,5 @@ class <%= migration_class_name %> < ActiveRecord::Migration
   <%- 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
index c75abd043c..f7caa43ac8 100644
--- a/activerecord/lib/rails/generators/active_record/model/model_generator.rb
+++ b/activerecord/lib/rails/generators/active_record/model/model_generator.rb
@@ -10,6 +10,7 @@ module ActiveRecord
       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"
 
       def create_migration_file
         return unless options[:migration] && options[:parent].nil?
diff --git a/activerecord/lib/rails/generators/active_record/model/templates/migration.rb b/activerecord/lib/rails/generators/active_record/model/templates/migration.rb
index 70e064be21..4f81a52fd0 100644
--- a/activerecord/lib/rails/generators/active_record/model/templates/migration.rb
+++ b/activerecord/lib/rails/generators/active_record/model/templates/migration.rb
@@ -1,5 +1,5 @@
 class <%= migration_class_name %> < ActiveRecord::Migration
-  def up
+  def change
     create_table :<%= table_name %> do |t|
 <% for attribute in attributes -%>
       t.<%= attribute.type %> :<%= attribute.name %>
@@ -8,9 +8,10 @@ class <%= migration_class_name %> < ActiveRecord::Migration
       t.timestamps
 <% end -%>
     end
-  end
-
-  def down
-    drop_table :<%= table_name %>
+<% if options[:indexes] -%>
+<% attributes.select {|attr| attr.reference? }.each do |attribute| -%>
+    add_index :<%= table_name %>, :<%= attribute.name %>_id
+<% end -%>
+<% end -%>
   end
 end
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..1c2942170e
--- /dev/null
+++ b/activerecord/test/active_record/connection_adapters/fake_adapter.rb
@@ -0,0 +1,36 @@
+module ActiveRecord
+  class Base
+    def self.fake_connection(config)
+      ConnectionAdapters::FakeAdapter.new nil, logger
+    end
+  end
+
+  module ConnectionAdapters
+    class FakeAdapter < AbstractAdapter
+      attr_accessor :tables, :primary_keys
+
+      def initialize(connection, logger)
+        super
+        @tables       = []
+        @primary_keys = {}
+        @columns      = Hash.new { |h,k| h[k] = [] }
+      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],
+          sql_type.to_s,
+          options[:null])
+      end
+
+      def columns(table_name, message)
+        @columns[table_name]
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapter_test.rb b/activerecord/test/cases/adapter_test.rb
index 646aa88d80..49b2e945c3 100644
--- a/activerecord/test/cases/adapter_test.rb
+++ b/activerecord/test/cases/adapter_test.rb
@@ -141,16 +141,4 @@ class AdapterTest < ActiveRecord::TestCase
       end
     end
   end
-
-  def test_add_limit_offset_should_sanitize_sql_injection_for_limit_without_comas
-    sql_inject = "1 select * from schema"
-    assert_no_match(/schema/, @connection.add_limit_offset!("", :limit=>sql_inject))
-    assert_no_match(/schema/, @connection.add_limit_offset!("", :limit=>sql_inject, :offset=>7))
-  end
-
-  def test_add_limit_offset_should_sanitize_sql_injection_for_limit_with_comas
-    sql_inject = "1, 7 procedure help()"
-    assert_no_match(/procedure/, @connection.add_limit_offset!("", :limit=>sql_inject))
-    assert_no_match(/procedure/, @connection.add_limit_offset!("", :limit=>sql_inject, :offset=>7))
-  end
 end
diff --git a/activerecord/test/cases/adapters/mysql/connection_test.rb b/activerecord/test/cases/adapters/mysql/connection_test.rb
index 62ffde558f..eb3f8143e7 100644
--- a/activerecord/test/cases/adapters/mysql/connection_test.rb
+++ b/activerecord/test/cases/adapters/mysql/connection_test.rb
@@ -102,7 +102,7 @@ class MysqlConnectionTest < ActiveRecord::TestCase
   end
 
   # Test that MySQL allows multiple results for stored procedures
-  if Mysql.const_defined?(:CLIENT_MULTI_RESULTS)
+  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}"
diff --git a/activerecord/test/cases/adapters/mysql/reserved_word_test.rb b/activerecord/test/cases/adapters/mysql/reserved_word_test.rb
index 90d8b0d923..43015098c9 100644
--- a/activerecord/test/cases/adapters/mysql/reserved_word_test.rb
+++ b/activerecord/test/cases/adapters/mysql/reserved_word_test.rb
@@ -78,24 +78,6 @@ class MysqlReservedWordTest < ActiveRecord::TestCase
   self.use_instantiated_fixtures = true
   self.use_transactional_fixtures = false
 
-  #fixtures :group
-
-  def test_fixtures
-    f = create_test_fixtures :select, :distinct, :group, :values, :distincts_selects
-
-    assert_nothing_raised {
-      f.each do |x|
-        x.delete_existing_fixtures
-      end
-    }
-
-    assert_nothing_raised {
-      f.each do |x|
-        x.insert_fixtures
-      end
-    }
-  end
-
   #activerecord model class with reserved-word table name
   def test_activerecord_model
     create_test_fixtures :select, :distinct, :group, :values, :distincts_selects
@@ -105,9 +87,9 @@ class MysqlReservedWordTest < ActiveRecord::TestCase
     assert_nothing_raised { x.save }
     x.order = 'y'
     assert_nothing_raised { x.save }
-    assert_nothing_raised { y = Group.find_by_order('y') }
-    assert_nothing_raised { y = Group.find(1) }
-    x = Group.find(1)
+    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
diff --git a/activerecord/test/cases/adapters/mysql2/reserved_word_test.rb b/activerecord/test/cases/adapters/mysql2/reserved_word_test.rb
index 90d8b0d923..1efa7deaeb 100644
--- a/activerecord/test/cases/adapters/mysql2/reserved_word_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/reserved_word_test.rb
@@ -78,24 +78,6 @@ class MysqlReservedWordTest < ActiveRecord::TestCase
   self.use_instantiated_fixtures = true
   self.use_transactional_fixtures = false
 
-  #fixtures :group
-
-  def test_fixtures
-    f = create_test_fixtures :select, :distinct, :group, :values, :distincts_selects
-
-    assert_nothing_raised {
-      f.each do |x|
-        x.delete_existing_fixtures
-      end
-    }
-
-    assert_nothing_raised {
-      f.each do |x|
-        x.insert_fixtures
-      end
-    }
-  end
-
   #activerecord model class with reserved-word table name
   def test_activerecord_model
     create_test_fixtures :select, :distinct, :group, :values, :distincts_selects
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index 234696adeb..b8abdface4 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -9,6 +9,11 @@ module ActiveRecord
                                        :timeout => 100
       end
 
+      def test_primary_key_returns_nil_for_no_pk
+        @conn.exec_query('create table ex(id int, data string)')
+        assert_nil @conn.primary_key('ex')
+      end
+
       def test_connection_no_db
         assert_raises(ArgumentError) do
           Base.sqlite3_connection {}
diff --git a/activerecord/test/cases/associations/belongs_to_associations_test.rb b/activerecord/test/cases/associations/belongs_to_associations_test.rb
index 1820f95261..9006914508 100644
--- a/activerecord/test/cases/associations/belongs_to_associations_test.rb
+++ b/activerecord/test/cases/associations/belongs_to_associations_test.rb
@@ -17,7 +17,7 @@ require 'models/essay'
 class BelongsToAssociationsTest < ActiveRecord::TestCase
   fixtures :accounts, :companies, :developers, :projects, :topics,
            :developers_projects, :computers, :authors, :author_addresses,
-           :posts, :tags, :taggings, :comments
+           :posts, :tags, :taggings, :comments, :sponsors, :members
 
   def test_belongs_to
     Client.find(3).firm.name
@@ -50,11 +50,6 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_nothing_raised { account.firm = account.firm }
   end
 
-  def test_triple_equality
-    assert Client.find(3).firm === Firm
-    assert Firm === Client.find(3).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) }
@@ -78,27 +73,14 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     Firm.create("name" => "Apple")
     Client.create("name" => "Citibank", :firm_name => "Apple")
     citibank_result = Client.find(:first, :conditions => {:name => "Citibank"}, :include => :firm_with_primary_key)
-    assert_not_nil citibank_result.instance_variable_get("@firm_with_primary_key")
+    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.find(:first, :conditions => {:name => "Citibank"}, :include => :firm_with_primary_key_symbols)
-    assert_not_nil citibank_result.instance_variable_get("@firm_with_primary_key_symbols")
-  end
-
-  def test_no_unexpected_aliasing
-    first_firm = companies(:first_firm)
-    another_firm = companies(:another_firm)
-
-    citibank = Account.create("credit_limit" => 10)
-    citibank.firm = first_firm
-    original_proxy = citibank.firm
-    citibank.firm = another_firm
-
-    assert_equal first_firm.object_id, original_proxy.target.object_id
-    assert_equal another_firm.object_id, citibank.firm.target.object_id
+    assert citibank_result.association_cache.key?(:firm_with_primary_key_symbols)
   end
 
   def test_creating_the_belonging_object
@@ -133,6 +115,23 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     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
@@ -159,6 +158,15 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_not_nil Company.find(3).firm_with_condition, "Microsoft should have a firm"
   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 Company.find(2).firm_with_select.attributes.size, 1
     assert_equal Company.find(2, :include => :firm_with_select ).firm_with_select.attributes.size, 1
@@ -175,17 +183,6 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal 0, Topic.find(debate.id).send(:read_attribute, "replies_count"), "First reply deleted"
   end
 
-  def test_belongs_to_with_primary_key_counter
-    debate = Topic.create("title" => "debate")
-    assert_equal 0, debate.send(:read_attribute, "replies_count"), "No replies yet"
-
-    trash = debate.replies_with_primary_key.create("title" => "blah!", "content" => "world around!")
-    assert_equal 1, Topic.find(debate.id).send(:read_attribute, "replies_count"), "First reply created"
-
-    trash.destroy
-    assert_equal 0, Topic.find(debate.id).send(:read_attribute, "replies_count"), "First reply deleted"
-  end
-
   def test_belongs_to_counter_with_assigning_nil
     p = Post.find(1)
     c = Comment.find(1)
@@ -198,16 +195,23 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal 1, Post.find(p.id).comments.size
   end
 
-  def test_belongs_to_with_primary_key_counter_with_assigning_nil
-    debate = Topic.create("title" => "debate")
-    reply  = Reply.create("title" => "blah!", "content" => "world around!", "parent_title" => "debate")
+  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
 
-    assert_equal debate.title, reply.parent_title
-    assert_equal 1, Topic.find(debate.id).send(:read_attribute, "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, Topic.find(debate.id).send(:read_attribute, "replies_count")
+    assert_equal 0, debate.reload.replies_count
+    assert_equal 0, debate2.reload.replies_count
   end
 
   def test_belongs_to_counter_with_reassigning
@@ -311,13 +315,21 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal Firm.find(:first, :order => "id"), c.firm_with_basic_id
   end
 
-  def test_forgetting_the_load_when_foreign_key_enters_late
-    c = Client.new
-    assert_nil c.firm_with_basic_id
+  def test_setting_foreign_key_after_nil_target_loaded
+    client = Client.new
+    client.firm_with_basic_id
+    client.firm_id = 1
 
-    c.firm_id = 1
-    # sometimes tests on Oracle fail if ORDER BY is not provided therefore add always :order with :first
-    assert_equal Firm.find(:first, :order => "id"), c.firm_with_basic_id
+    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_field_name_same_as_foreign_key
@@ -419,6 +431,18 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     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")
@@ -488,39 +512,118 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_reassigning_the_parent_id_updates_the_object
-    original_parent = Firm.create! :name => "original"
-    updated_parent = Firm.create! :name => "updated"
+    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)
 
-    client = Client.new("client_of" => original_parent.id)
-    assert_equal original_parent, client.firm
-    assert_equal original_parent, client.firm_with_condition
-    assert_equal original_parent, client.firm_with_other_name
+    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 = updated_parent.id
-    assert_equal updated_parent, client.firm
-    assert_equal updated_parent, client.firm_with_condition
-    assert_equal updated_parent, client.firm_with_other_name
+    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
-    member1 = Member.create!
-    member2 = Member.create!
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+
+    sponsor.sponsorable
+    proxy = sponsor.send(:association_instance_get, :sponsorable)
 
-    sponsor = Sponsor.new("sponsorable_type" => "Member", "sponsorable_id" => member1.id)
-    assert_equal member1, sponsor.sponsorable
+    assert !proxy.stale_target?
+    assert_equal members(:groucho), sponsor.sponsorable
 
-    sponsor.sponsorable_id = member2.id
-    assert_equal member2, 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
-    member1 = Member.create!
+    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 = Sponsor.new("sponsorable_type" => "Member", "sponsorable_id" => member1.id)
-    assert_equal member1, sponsor.sponsorable
+    sponsor.sponsorable_type = 'Firm'
 
-    sponsor.sponsorable_type = "Firm"
-    assert_not_equal member1, sponsor.sponsorable
+    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 'post.reload.taggings_count', -1 do
+      assert_difference 'comment.reload.taggings_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
 end
diff --git a/activerecord/test/cases/associations/callbacks_test.rb b/activerecord/test/cases/associations/callbacks_test.rb
index 6a30e2905b..2d0d4541b4 100644
--- a/activerecord/test/cases/associations/callbacks_test.rb
+++ b/activerecord/test/cases/associations/callbacks_test.rb
@@ -3,6 +3,7 @@ require 'models/post'
 require 'models/author'
 require 'models/project'
 require 'models/developer'
+require 'models/company'
 
 class AssociationCallbacksTest < ActiveRecord::TestCase
   fixtures :posts, :authors, :projects, :developers
@@ -81,6 +82,14 @@ class AssociationCallbacksTest < ActiveRecord::TestCase
     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)
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
index fb59f63f91..d75791cab9 100644
--- 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
@@ -27,6 +27,7 @@ class EagerLoadIncludeFullStiClassNamesTest < ActiveRecord::TestCase
     post = Namespaced::Post.find_by_title( 'Great stuff', :include => :tagging )
     assert_nil post.tagging
 
+    ActiveRecord::IdentityMap.clear
     ActiveRecord::Base.store_full_sti_class = true
     post = Namespaced::Post.find_by_title( 'Great stuff', :include => :tagging )
     assert_instance_of Tagging, post.tagging
diff --git a/activerecord/test/cases/associations/eager_load_nested_include_test.rb b/activerecord/test/cases/associations/eager_load_nested_include_test.rb
index c7671a8c22..2cf9f89c3c 100644
--- a/activerecord/test/cases/associations/eager_load_nested_include_test.rb
+++ b/activerecord/test/cases/associations/eager_load_nested_include_test.rb
@@ -1,9 +1,11 @@
 require 'cases/helper'
 require 'models/post'
+require 'models/tag'
 require 'models/author'
 require 'models/comment'
 require 'models/category'
 require 'models/categorization'
+require 'models/tagging'
 require 'active_support/core_ext/array/random_access'
 
 module Remembered
diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index 949fbb9300..ed6337b596 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -17,18 +17,28 @@ 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, :author_addresses, :categories, :categories_posts,
-            :companies, :accounts, :tags, :taggings, :people, :readers,
+            :companies, :accounts, :tags, :taggings, :people, :readers, :categorizations,
             :owners, :pets, :author_favorites, :jobs, :references, :subscribers, :subscriptions, :books,
-            :developers, :projects, :developers_projects
+            :developers, :projects, :developers_projects, :members, :memberships, :clubs, :sponsors
 
   def setup
     # preheat table existence caches
     Comment.find_by_id(1)
   end
 
+  def test_eager_with_has_one_through_join_model_with_conditions_on_the_through
+    member = Member.find(members(:some_other_guy).id, :include => :favourite_club)
+    assert_nil member.favourite_club
+  end
+
   def test_loading_with_one_association
     posts = Post.find(:all, :include => :comments)
     post = posts.find { |p| p.id == 1 }
@@ -110,30 +120,29 @@ class EagerAssociationTest < ActiveRecord::TestCase
 
   def test_load_associated_records_in_one_query_when_adapter_has_no_limit
     Post.connection.expects(:in_clause_length).at_least_once.returns(nil)
-    Post.expects(:i_was_called).with([1,2,3,4,5,6,7]).returns([1])
-    associated_records = Post.send(:associated_records, [1,2,3,4,5,6,7]) do |some_ids|
-      Post.i_was_called(some_ids)
+
+    post = posts(:welcome)
+    assert_queries(2) do
+      Post.includes(:comments).where(:id => post.id).to_a
     end
-    assert_equal [1], associated_records
   end
 
   def test_load_associated_records_in_several_queries_when_many_ids_passed
-    Post.connection.expects(:in_clause_length).at_least_once.returns(5)
-    Post.expects(:i_was_called).with([1,2,3,4,5]).returns([1])
-    Post.expects(:i_was_called).with([6,7]).returns([6])
-    associated_records = Post.send(:associated_records, [1,2,3,4,5,6,7]) do |some_ids|
-      Post.i_was_called(some_ids)
+    Post.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
-    assert_equal [1,6], associated_records
   end
 
   def test_load_associated_records_in_one_query_when_a_few_ids_passed
-    Post.connection.expects(:in_clause_length).at_least_once.returns(5)
-    Post.expects(:i_was_called).with([1,2,3]).returns([1])
-    associated_records = Post.send(:associated_records, [1,2,3]) do |some_ids|
-      Post.i_was_called(some_ids)
+    Post.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
-    assert_equal [1], associated_records
   end
 
   def test_including_duplicate_objects_from_belongs_to
@@ -175,7 +184,7 @@ class EagerAssociationTest < ActiveRecord::TestCase
     author = authors(:david)
     post = author.post_about_thinking_with_last_comment
     last_comment = post.last_comment
-    author = assert_queries(3) { Author.find(author.id, :include => {:post_about_thinking_with_last_comment => :last_comment})} # find the author, then find the posts, then find the comments
+    author = assert_queries(ActiveRecord::IdentityMap.enabled? ? 2 : 3) { Author.find(author.id, :include => {:post_about_thinking_with_last_comment => :last_comment})} # 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
@@ -186,7 +195,7 @@ class EagerAssociationTest < ActiveRecord::TestCase
     post = posts(:welcome)
     author = post.author
     author_address = author.author_address
-    post = assert_queries(3) { Post.find(post.id, :include => {:author_with_address => :author_address}) } # find the post, then find the author, then find the address
+    post = assert_queries(ActiveRecord::IdentityMap.enabled? ? 2 : 3) { Post.find(post.id, :include => {:author_with_address => :author_address}) } # 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
@@ -202,6 +211,15 @@ class EagerAssociationTest < ActiveRecord::TestCase
     end
   end
 
+  def test_finding_with_includes_on_null_belongs_to_polymorphic_association
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    sponsor.update_attributes!(:sponsorable => nil)
+    sponsor = assert_queries(1) { Sponsor.find(sponsor.id, :include => :sponsorable) }
+    assert_no_queries do
+      assert_equal nil, sponsor.sponsorable
+    end
+  end
+
   def test_loading_from_an_association
     posts = authors(:david).posts.find(:all, :include => :comments, :order => "posts.id")
     assert_equal 2, posts.first.comments.size
@@ -650,7 +668,11 @@ class EagerAssociationTest < ActiveRecord::TestCase
   end
 
   def test_preload_with_interpolation
-    assert_equal [comments(:greetings)], Post.find(posts(:welcome).id, :include => :comments_with_interpolated_conditions).comments_with_interpolated_conditions
+    post = Post.includes(:comments_with_interpolated_conditions).find(posts(:welcome).id)
+    assert_equal [comments(:greetings)], post.comments_with_interpolated_conditions
+
+    post = Post.joins(:comments_with_interpolated_conditions).find(posts(:welcome).id)
+    assert_equal [comments(:greetings)], post.comments_with_interpolated_conditions
   end
 
   def test_polymorphic_type_condition
@@ -794,18 +816,18 @@ class EagerAssociationTest < ActiveRecord::TestCase
     assert_equal [posts(:welcome)], posts
     assert_equal authors(:david), assert_no_queries { posts[0].author}
 
-    posts = assert_queries(2) do
+    posts = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
       Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => [:comments], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
     end
     assert_equal [posts(:welcome)], posts
     assert_equal authors(:david), assert_no_queries { posts[0].author}
 
-    posts = assert_queries(2) do
+    posts = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
       Post.find(:all, :include => :author, :joins => {:taggings => :tag}, :conditions => "tags.name = 'General'", :order => 'posts.id')
     end
     assert_equal posts(:welcome, :thinking), posts
 
-    posts = assert_queries(2) do
+    posts = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
       Post.find(:all, :include => :author, :joins => {:taggings => {:tag => :taggings}}, :conditions => "taggings_tags.super_tag_id=2", :order => 'posts.id')
     end
     assert_equal posts(:welcome, :thinking), posts
@@ -819,7 +841,7 @@ class EagerAssociationTest < ActiveRecord::TestCase
     assert_equal [posts(:welcome)], posts
     assert_equal authors(:david), assert_no_queries { posts[0].author}
 
-    posts = assert_queries(2) do
+    posts = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
       Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => ["INNER JOIN comments on comments.post_id = posts.id"], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
     end
     assert_equal [posts(:welcome)], posts
@@ -836,6 +858,8 @@ class EagerAssociationTest < ActiveRecord::TestCase
   end
 
   def test_eager_loading_with_conditions_on_join_model_preloads
+    Author.columns
+
     authors = assert_queries(2) do
       Author.find(:all, :include => :author_address, :joins => :comments, :conditions => "posts.title like 'Welcome%'")
     end
@@ -881,25 +905,55 @@ class EagerAssociationTest < ActiveRecord::TestCase
   end
 
   def test_preload_has_one_using_primary_key
-    expected = Firm.find(:first).account_using_primary_key
-    firm = Firm.find :first, :include => :account_using_primary_key
+    expected = accounts(:signals37)
+    firm = Firm.find :first, :include => :account_using_primary_key, :order => 'companies.id'
     assert_no_queries do
       assert_equal expected, firm.account_using_primary_key
     end
   end
 
   def test_include_has_one_using_primary_key
-    expected = Firm.find(1).account_using_primary_key
+    expected = accounts(:signals37)
     firm = Firm.find(:all, :include => :account_using_primary_key, :order => 'accounts.id').detect {|f| f.id == 1}
     assert_no_queries do
       assert_equal expected, firm.account_using_primary_key
     end
   end
 
-  def test_preloading_empty_polymorphic_parent
+  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))
 
-    assert_queries(2) { @tagging = Tagging.preload(:taggable).find(t.id) }
-    assert_no_queries { assert ! @tagging.taggable }
+    tagging = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 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
 end
diff --git a/activerecord/test/cases/associations/extension_test.rb b/activerecord/test/cases/associations/extension_test.rb
index efaab8569e..24830a661a 100644
--- a/activerecord/test/cases/associations/extension_test.rb
+++ b/activerecord/test/cases/associations/extension_test.rb
@@ -30,6 +30,11 @@ class AssociationsExtensionsTest < ActiveRecord::TestCase
     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
@@ -47,12 +52,16 @@ class AssociationsExtensionsTest < ActiveRecord::TestCase
   end
 
   def test_extension_name
-    extension = Proc.new {}
-    name = :association_name
-
-    assert_equal 'DeveloperAssociationNameAssociationExtension', Developer.send(:create_extension_modules, name, extension, []).first.name
-    assert_equal 'MyApplication::Business::DeveloperAssociationNameAssociationExtension', MyApplication::Business::Developer.send(:create_extension_modules, name, extension, []).first.name
-    assert_equal 'MyApplication::Business::DeveloperAssociationNameAssociationExtension', MyApplication::Business::Developer.send(:create_extension_modules, name, extension, []).first.name
-    assert_equal 'MyApplication::Business::DeveloperAssociationNameAssociationExtension', MyApplication::Business::Developer.send(:create_extension_modules, name, extension, []).first.name
+    assert_equal 'DeveloperAssociationNameAssociationExtension', extension_name(Developer)
+    assert_equal 'MyApplication::Business::DeveloperAssociationNameAssociationExtension', extension_name(MyApplication::Business::Developer)
+    assert_equal 'MyApplication::Business::DeveloperAssociationNameAssociationExtension', extension_name(MyApplication::Business::Developer)
   end
+
+  private
+
+    def extension_name(model)
+      builder = ActiveRecord::Associations::Builder::HasMany.new(model, :association_name, {}) { }
+      builder.send(:wrap_block_extension)
+      builder.options[:extend].first.name
+    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
index 513f76255c..73d02c9676 100644
--- 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
@@ -72,7 +72,7 @@ class DeveloperWithCounterSQL < ActiveRecord::Base
     :join_table => "developers_projects",
     :association_foreign_key => "project_id",
     :foreign_key => "developer_id",
-    :counter_sql => 'SELECT COUNT(*) AS count_all FROM projects INNER JOIN developers_projects ON projects.id = developers_projects.project_id WHERE developers_projects.developer_id =#{id}'
+    :counter_sql => proc { "SELECT COUNT(*) AS count_all FROM projects INNER JOIN developers_projects ON projects.id = developers_projects.project_id WHERE developers_projects.developer_id =#{id}" }
 end
 
 class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
@@ -101,38 +101,6 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     assert_equal 't1', record[1]
   end
 
-  def test_should_record_timestamp_for_join_table
-    setup_data_for_habtm_case
-
-    con = ActiveRecord::Base.connection
-    sql = 'select * from countries_treaties'
-    record = con.select_rows(sql).last
-    assert_not_nil record[2]
-    assert_not_nil record[3]
-    if current_adapter?(:Mysql2Adapter, :OracleAdapter)
-      assert_match %r{\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}}, record[2].to_s(:db)
-      assert_match %r{\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}}, record[3].to_s(:db)
-    else
-      assert_match %r{\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}}, record[2]
-      assert_match %r{\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}}, record[3]
-    end
-  end
-
-  def test_should_record_timestamp_for_join_table_only_if_timestamp_should_be_recorded
-    begin
-      Treaty.record_timestamps = false
-      setup_data_for_habtm_case
-
-      con = ActiveRecord::Base.connection
-      sql = 'select * from countries_treaties'
-      record = con.select_rows(sql).last
-      assert_nil record[2]
-      assert_nil record[3]
-    ensure
-      Treaty.record_timestamps = true
-    end
-  end
-
   def test_has_and_belongs_to_many
     david = Developer.find(1)
 
@@ -218,34 +186,6 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     assert_equal 2, aredridel.projects(true).size
   end
 
-  def test_adding_uses_default_values_on_join_table
-    ac = projects(:action_controller)
-    assert !developers(:jamis).projects.include?(ac)
-    developers(:jamis).projects << ac
-
-    assert developers(:jamis, :reload).projects.include?(ac)
-    project = developers(:jamis).projects.detect { |p| p == ac }
-    assert_equal 1, project.access_level.to_i
-  end
-
-  def test_habtm_attribute_access_and_respond_to
-    project = developers(:jamis).projects[0]
-    assert project.has_attribute?("name")
-    assert project.has_attribute?("joined_on")
-    assert project.has_attribute?("access_level")
-    assert project.respond_to?("name")
-    assert project.respond_to?("name=")
-    assert project.respond_to?("name?")
-    assert project.respond_to?("joined_on")
-    # given that the 'join attribute' won't be persisted, I don't
-    # think we should define the mutators
-    #assert project.respond_to?("joined_on=")
-    assert project.respond_to?("joined_on?")
-    assert project.respond_to?("access_level")
-    #assert project.respond_to?("access_level=")
-    assert project.respond_to?("access_level?")
-  end
-
   def test_habtm_adding_before_save
     no_of_devels = Developer.count
     no_of_projects = Project.count
@@ -425,38 +365,41 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
   def test_removing_associations_on_destroy
     david = DeveloperWithBeforeDestroyRaise.find(1)
     assert !david.projects.empty?
-    assert_raise(RuntimeError) { david.destroy }
+    david.destroy
     assert david.projects.empty?
     assert DeveloperWithBeforeDestroyRaise.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = 1").empty?
   end
 
-  def test_additional_columns_from_join_table
-    assert_date_from_db Date.new(2004, 10, 10), Developer.find(1).projects.first.joined_on.to_date
-  end
-
   def test_destroying
     david = Developer.find(1)
-    active_record = Project.find(1)
+    project = Project.find(1)
     david.projects.reload
     assert_equal 2, david.projects.size
-    assert_equal 3, active_record.developers.size
+    assert_equal 3, project.developers.size
 
-    assert_difference "Project.count", -1 do
-      david.projects.destroy(active_record)
+    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_array
+  def test_destroying_many
     david = Developer.find(1)
     david.projects.reload
+    projects = Project.all
 
-    assert_difference "Project.count", -Project.count do
-      david.projects.destroy(Project.find(:all))
+    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
@@ -465,7 +408,14 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     david = Developer.find(1)
     david.projects.reload
     assert !david.projects.empty?
-    david.projects.destroy_all
+
+    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
@@ -675,25 +625,6 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     assert_respond_to categories(:technology).select_testing_posts.find(:first), :correctness_marker
   end
 
-  def test_updating_attributes_on_rich_associations
-    david = projects(:action_controller).developers.first
-    david.name = "DHH"
-    assert_raise(ActiveRecord::ReadOnlyRecord) { david.save! }
-  end
-
-  def test_updating_attributes_on_rich_associations_with_limited_find_from_reflection
-    david = projects(:action_controller).selected_developers.first
-    david.name = "DHH"
-    assert_nothing_raised { david.save! }
-  end
-
-
-  def test_updating_attributes_on_rich_associations_with_limited_find
-    david = projects(:action_controller).developers.find(:all, :select => "developers.*").first
-    david.name = "DHH"
-    assert david.save!
-  end
-
   def test_join_table_alias
     assert_equal 3, Developer.find(:all, :include => {:projects => :developers}, :conditions => 'developers_projects_join.joined_on IS NOT NULL').size
   end
@@ -840,10 +771,13 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     david = Developer.find(1)
     # clear cache possibly created by other tests
     david.projects.reset_column_information
-    assert_queries(0) { david.projects.columns; david.projects.columns }
-    # and again to verify that reset_column_information clears the cache correctly
+
+    # One query for columns, one for primary key
+    assert_queries(2) { david.projects.columns; david.projects.columns }
+
+    ## and again to verify that reset_column_information clears the cache correctly
     david.projects.reset_column_information
-    assert_queries(0) { david.projects.columns; david.projects.columns }
+    assert_queries(2) { david.projects.columns; david.projects.columns }
   end
 
   def test_attributes_are_being_set_when_initialized_from_habm_association_with_where_clause
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index fb772bb8e6..ad774eb9ce 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -43,7 +43,7 @@ end
 class HasManyAssociationsTest < ActiveRecord::TestCase
   fixtures :accounts, :categories, :companies, :developers, :projects,
            :developers_projects, :topics, :authors, :comments,
-           :people, :posts, :readers, :taggings
+           :people, :posts, :readers, :taggings, :cars
 
   def setup
     Client.destroyed_client_ids.clear
@@ -66,14 +66,36 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal 'exotic', bulb.name
   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)
+    original_scoped_methods = Bulb.scoped_methods
+
+    bulb = car.bulbs.build
+    assert_equal original_scoped_methods, bulb.scoped_methods_after_initialize
+
+    bulb = car.bulbs.create
+    assert_equal original_scoped_methods, bulb.scoped_methods_after_initialize
+
+    bulb = car.bulbs.create!
+    assert_equal original_scoped_methods, bulb.scoped_methods_after_initialize
+  end
+
   def test_no_sql_should_be_fired_if_association_already_loaded
     Car.create(:name => 'honda')
     bulbs = Car.first.bulbs
     bulbs.inspect # to load all instances of bulbs
+
     assert_no_queries do
       bulbs.first()
       bulbs.first({})
     end
+
+    assert_no_queries do
+      bulbs.last()
+      bulbs.last({})
+    end
   end
 
   def test_create_resets_cached_counters
@@ -257,7 +279,6 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
 
   def test_counting_using_finder_sql
     assert_equal 2, Firm.find(4).clients_using_sql.count
-    assert_equal 2, Firm.find(4).clients_using_multiline_sql.count
   end
 
   def test_belongs_to_sanity
@@ -608,7 +629,7 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal topic.replies.to_a.size, topic.replies_count
   end
 
-  def test_deleting_updates_counter_cache_without_dependent_destroy
+  def test_deleting_updates_counter_cache_without_dependent_option
     post = posts(:welcome)
 
     assert_difference "post.reload.taggings_count", -1 do
@@ -616,6 +637,24 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     end
   end
 
+  def test_deleting_updates_counter_cache_with_dependent_delete_all
+    post = posts(:welcome)
+    post.update_attribute(:taggings_with_delete_all_count, post.taggings_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_attribute(:taggings_with_destroy_count, post.taggings_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_deleting_a_collection
     force_signal37_to_load_all_clients_of_firm
     companies(:first_firm).clients_of_firm.create("name" => "Another Client")
@@ -628,8 +667,10 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
   def test_delete_all
     force_signal37_to_load_all_clients_of_firm
     companies(:first_firm).clients_of_firm.create("name" => "Another Client")
-    assert_equal 2, companies(:first_firm).clients_of_firm.size
-    companies(:first_firm).clients_of_firm.delete_all
+    clients = companies(:first_firm).clients_of_firm.to_a
+    assert_equal 2, clients.count
+    deleted = companies(:first_firm).clients_of_firm.delete_all
+    assert_equal clients.sort_by(&:id), deleted.sort_by(&:id)
     assert_equal 0, companies(:first_firm).clients_of_firm.size
     assert_equal 0, companies(:first_firm).clients_of_firm(true).size
   end
@@ -649,11 +690,12 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     client_id = firm.clients_of_firm.first.id
     assert_equal 1, firm.clients_of_firm.size
 
-    firm.clients_of_firm.clear
+    cleared = 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]
+    assert_equal firm.clients_of_firm.object_id, cleared.object_id
 
     # Should not be destroyed since the association is not dependent.
     assert_nothing_raised do
@@ -664,9 +706,9 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
   def test_clearing_updates_counter_cache
     topic = Topic.first
 
-    topic.replies.clear
-    topic.reload
-    assert_equal 0, topic.replies_count
+    assert_difference 'topic.reload.replies_count', -1 do
+      topic.replies.clear
+    end
   end
 
   def test_clearing_a_dependent_association_collection
@@ -963,6 +1005,19 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert !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_get_ids
     assert_equal [companies(:first_client).id, companies(:second_client).id], companies(:first_firm).client_ids
   end
@@ -1302,4 +1357,11 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     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
 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
index 5fac52257c..9adaebe924 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -20,12 +20,15 @@ require 'models/subscription'
 require 'models/essay'
 require 'models/category'
 require 'models/owner'
+require 'models/categorization'
+require 'models/member'
+require 'models/membership'
+require 'models/club'
 
 class HasManyThroughAssociationsTest < ActiveRecord::TestCase
-  fixtures :posts, :readers, :people, :comments, :authors,
-           :owners, :pets, :toys, :jobs, :references, :companies,
-           :subscribers, :books, :subscriptions, :developers,
-           :essays, :categories, :owners
+  fixtures :posts, :readers, :people, :comments, :authors, :categories, :taggings, :tags,
+           :owners, :pets, :toys, :jobs, :references, :companies, :members, :author_addresses,
+           :subscribers, :books, :subscriptions, :developers, :categorizations, :essays
 
   # Dummies to force column loads so query counts are clean.
   def setup
@@ -33,6 +36,13 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     Reader.create :person_id => 0, :post_id => 0
   end
 
+  def test_include?
+    person = Person.new
+    post = Post.new
+    person.posts << post
+    assert person.posts.include?(post)
+  end
+
   def test_associate_existing
     assert_queries(2) { posts(:thinking); people(:david) }
 
@@ -47,6 +57,16 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert posts(:thinking).reload.people(true).include?(people(:david))
   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_associating_new
     assert_queries(1) { posts(:thinking) }
     new_person = nil # so block binding catches it
@@ -94,6 +114,24 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     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_delete_association
     assert_queries(2){posts(:welcome);people(:michael); }
 
@@ -109,8 +147,10 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_destroy_association
-    assert_difference ["Person.count", "Reader.count"], -1 do
-      posts(:welcome).people.destroy(people(:michael))
+    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?
@@ -118,8 +158,10 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_destroy_all
-    assert_difference ["Person.count", "Reader.count"], -1 do
-      posts(:welcome).people.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?
@@ -132,6 +174,137 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     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.taggings_count', '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_attribute(:tags_with_destroy_count, post.tags.count)
+
+    assert_difference ['post.reload.taggings_count', '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_attribute(:tags_with_nullify_count, post.tags.count)
+
+    assert_no_difference 'post.reload.taggings_count' do
+      assert_difference 'post.reload.tags_with_nullify_count', -1 do
+        posts(:welcome).tags_with_nullify.delete(tag)
+      end
+    end
+  end
+
   def test_replace_association
     assert_queries(4){posts(:welcome);people(:david);people(:michael); posts(:welcome).people(true)}
 
@@ -326,12 +499,8 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert_equal 2, people(:michael).jobs.size
   end
 
-  def test_get_ids_for_belongs_to_source
-    assert_sql(/DISTINCT/) { assert_equal [posts(:welcome).id, posts(:authorless).id].sort, people(:michael).post_ids.sort }
-  end
-
-  def test_get_ids_for_has_many_source
-    assert_equal [comments(:eager_other_comment1).id], authors(:mary).comment_ids
+  def test_get_ids
+    assert_equal [posts(:welcome).id, posts(:authorless).id].sort, people(:michael).post_ids.sort
   end
 
   def test_get_ids_for_loaded_associations
@@ -392,6 +561,41 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     ].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.map(&:agents).flatten, 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_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
@@ -478,4 +682,88 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     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').all, 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'], author.comments.select('comments.body').first.attributes.keys
+  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_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_interpolated_conditions
+    post = posts(:welcome)
+    assert !post.tags.empty?
+    assert_equal post.tags, post.interpolated_tags
+    assert_equal post.tags, post.interpolated_tags_2
+  end
+
+  def test_primary_key_option_on_source
+    post     = posts(:welcome)
+    category = categories(:general)
+    categorization = 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
 end
diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
index 64449df8f5..c1dad5e246 100644
--- a/activerecord/test/cases/associations/has_one_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -2,9 +2,13 @@ require "cases/helper"
 require 'models/developer'
 require 'models/project'
 require 'models/company'
+require 'models/ship'
+require 'models/pirate'
+require 'models/bulb'
 
 class HasOneAssociationsTest < ActiveRecord::TestCase
-  fixtures :accounts, :companies, :developers, :projects, :developers_projects
+  self.use_transactional_fixtures = false unless supports_savepoints?
+  fixtures :accounts, :companies, :developers, :projects, :developers_projects, :ships, :pirates
 
   def setup
     Account.destroyed_account_ids.clear
@@ -62,11 +66,6 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     assert_nothing_raised { company.account = company.account }
   end
 
-  def test_triple_equality
-    assert Account === companies(:first_firm).account
-    assert companies(:first_firm).account === 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) }
@@ -91,18 +90,18 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
   def test_nullification_on_association_change
     firm = companies(:rails_core)
     old_account_id = firm.account.id
-    firm.account = Account.new
+    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_association_change_calls_delete
-    companies(:first_firm).deletable_account = Account.new
+    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
+    companies(:first_firm).account = Account.new(:credit_limit => 5)
     assert_equal [companies(:first_firm).id], Account.destroyed_account_ids[companies(:first_firm).id]
   end
 
@@ -116,35 +115,6 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     assert_equal company.account, account
   end
 
-  def test_assignment_without_replacement
-    apple = Firm.create("name" => "Apple")
-    citibank = Account.create("credit_limit" => 10)
-    apple.account = citibank
-    assert_equal apple.id, citibank.firm_id
-
-    hsbc = apple.build_account({ :credit_limit => 20}, false)
-    assert_equal apple.id, hsbc.firm_id
-    hsbc.save
-    assert_equal apple.id, citibank.firm_id
-
-    nykredit = apple.create_account({ :credit_limit => 30}, false)
-    assert_equal apple.id, nykredit.firm_id
-    assert_equal apple.id, citibank.firm_id
-    assert_equal apple.id, hsbc.firm_id
-  end
-
-  def test_assignment_without_replacement_on_create
-    apple = Firm.create("name" => "Apple")
-    citibank = Account.create("credit_limit" => 10)
-    apple.account = citibank
-    assert_equal apple.id, citibank.firm_id
-
-    hsbc = apple.create_account({:credit_limit => 10}, false)
-    assert_equal apple.id, hsbc.firm_id
-    hsbc.save
-    assert_equal apple.id, citibank.firm_id
-  end
-
   def test_dependence
     num_accounts = Account.count
 
@@ -193,13 +163,18 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     assert_equal account, firm.account
   end
 
-  def test_build_association_twice_without_saving_affects_nothing
-    count_of_account = Account.count
-    firm = Firm.find(:first)
-    firm.build_account("credit_limit" => 1000)
-    firm.build_account("credit_limit" => 2000)
+  def test_build_and_create_should_not_happen_within_scope
+    pirate = pirates(:blackbeard)
+    original_scoped_methods = Bulb.scoped_methods.dup
 
-    assert_equal count_of_account, Account.count
+    bulb = pirate.build_bulb
+    assert_equal original_scoped_methods, bulb.scoped_methods_after_initialize
+
+    bulb = pirate.create_bulb
+    assert_equal original_scoped_methods, bulb.scoped_methods_after_initialize
+
+    bulb = pirate.create_bulb!
+    assert_equal original_scoped_methods, bulb.scoped_methods_after_initialize
   end
 
   def test_create_association
@@ -208,25 +183,32 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     assert_equal account, firm.reload.account
   end
 
-  def test_build
-    firm = Firm.new("name" => "GlobalMegaCorp")
-    firm.save
+  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
 
-    firm.account = account = Account.new("credit_limit" => 1000)
-    assert_equal account, firm.account
-    assert account.save
-    assert_equal account, firm.account
+  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_failing_build_association
+  def test_build
     firm = Firm.new("name" => "GlobalMegaCorp")
     firm.save
 
-    firm.account = account = Account.new
+    firm.account = account = Account.new("credit_limit" => 1000)
     assert_equal account, firm.account
-    assert !account.save
+    assert account.save
     assert_equal account, firm.account
-    assert_equal ["can't be empty"], account.errors["credit_limit"]
   end
 
   def test_create
@@ -330,4 +312,51 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     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_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
 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
index fc56233ba8..9ba5549277 100644
--- a/activerecord/test/cases/associations/has_one_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_through_associations_test.rb
@@ -13,10 +13,12 @@ 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, :categories, :authors, :essays, :owners
+           :dashboards, :speedometers, :authors, :posts, :comments, :categories, :essays, :owners
 
   def setup
     @member = members(:groucho)
@@ -26,10 +28,6 @@ class HasOneThroughAssociationsTest < ActiveRecord::TestCase
     assert_equal clubs(:boring_club), @member.club
   end
 
-  def test_has_one_through_with_has_many
-    assert_equal clubs(:moustache_club), @member.favourite_club
-  end
-
   def test_creating_association_creates_through_record
     new_member = Member.create(:name => "Chris")
     new_member.club = Club.create(:name => "LRUG")
@@ -89,6 +87,18 @@ class HasOneThroughAssociationsTest < ActiveRecord::TestCase
     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.find(@member.id, :include => :favourite_club).favourite_club
+    memberships(:membership_of_favourite_club).update_attribute(:favourite, false)
+    assert_equal nil,                    Member.find(@member.id, :include => :favourite_club).reload.favourite_club
+
+    # conditions on the source table
+    assert_equal clubs(:moustache_club), Member.find(@member.id, :include => :hairy_club).hairy_club
+    clubs(:moustache_club).update_attribute(:name, "Association of Clean-Shaven Persons")
+    assert_equal nil,                    Member.find(@member.id, :include => :hairy_club).reload.hairy_club
+  end
+
   def test_has_one_through_polymorphic_with_source_type
     assert_equal members(:groucho), clubs(:moustache_club).sponsored_member
   end
@@ -132,7 +142,7 @@ class HasOneThroughAssociationsTest < ActiveRecord::TestCase
   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.club.target
+    assert_equal new_club, new_member.association(:club).target
   end
 
   def test_has_one_through_proxy_should_not_respond_to_private_methods
@@ -190,7 +200,7 @@ class HasOneThroughAssociationsTest < ActiveRecord::TestCase
       MemberDetail.find(:all, :include => :member_type)
     end
     @new_detail = @member_details[0]
-    assert @new_detail.loaded_member_type?
+    assert @new_detail.send(:association, :member_type).loaded?
     assert_not_nil assert_no_queries { @new_detail.member_type }
   end
 
@@ -253,4 +263,51 @@ class HasOneThroughAssociationsTest < ActiveRecord::TestCase
     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
 end
diff --git a/activerecord/test/cases/associations/identity_map_test.rb b/activerecord/test/cases/associations/identity_map_test.rb
new file mode 100644
index 0000000000..9b8635774c
--- /dev/null
+++ b/activerecord/test/cases/associations/identity_map_test.rb
@@ -0,0 +1,137 @@
+require "cases/helper"
+require 'models/author'
+require 'models/post'
+
+if ActiveRecord::IdentityMap.enabled?
+class InverseHasManyIdentityMapTest < ActiveRecord::TestCase
+  fixtures :authors, :posts
+
+  def test_parent_instance_should_be_shared_with_every_child_on_find
+    m = Author.first
+    is = m.posts
+    is.each do |i|
+      assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+      m.name = 'Bongo'
+      assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+      i.author.name = 'Mungo'
+      assert_equal m.name, i.author.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 = Author.find(:first, :include => :posts)
+    is = m.posts
+    is.each do |i|
+      assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+      m.name = 'Bongo'
+      assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+      i.author.name = 'Mungo'
+      assert_equal m.name, i.author.name, "Name of man should be the same after changes to child-owned instance"
+    end
+
+    m = Author.find(:first, :include => :posts, :order => 'posts.id')
+    is = m.posts
+    is.each do |i|
+      assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+      m.name = 'Bongo'
+      assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+      i.author.name = 'Mungo'
+      assert_equal m.name, i.author.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_built_child
+    m = Author.first
+    i = m.posts.build(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
+    assert_not_nil i.author
+    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+    i.author.name = 'Mungo'
+    assert_equal m.name, i.author.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_block_style_built_child
+    m = Author.first
+    i = m.posts.build {|ii| ii.title = 'Industrial Revolution Re-enactment'; ii.body = 'Lorem ipsum'}
+    assert_not_nil i.title, "Child attributes supplied to build via blocks should be populated"
+    assert_not_nil i.author
+    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+    i.author.name = 'Mungo'
+    assert_equal m.name, i.author.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 = Author.first
+    i = m.posts.create(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
+    assert_not_nil i.author
+    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+    i.author.name = 'Mungo'
+    assert_equal m.name, i.author.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_via_bang_method_child
+    m = Author.first
+    i = m.posts.create!(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
+    assert_not_nil i.author
+    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+    i.author.name = 'Mungo'
+    assert_equal m.name, i.author.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 = Author.first
+    i = m.posts.create {|ii| ii.title = 'Industrial Revolution Re-enactment'; ii.body = 'Lorem ipsum'}
+    assert_not_nil i.title, "Child attributes supplied to create via blocks should be populated"
+    assert_not_nil i.author
+    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+    i.author.name = 'Mungo'
+    assert_equal m.name, i.author.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_poked_in_child
+    m = Author.first
+    i = Post.create(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
+    m.posts << i
+    assert_not_nil i.author
+    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+    i.author.name = 'Mungo'
+    assert_equal m.name, i.author.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 = Author.first
+    i = Post.new(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
+    m.posts = [i]
+    assert_same m, i.author
+    assert_not_nil i.author
+    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+    i.author.name = 'Mungo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to replaced-child-owned instance"
+  end
+
+  def test_parent_instance_should_be_shared_with_replaced_via_method_children
+    m = Author.first
+    i = Post.new(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
+    m.posts = [i]
+    assert_not_nil i.author
+    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
+    m.name = 'Bongo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
+    i.author.name = 'Mungo'
+    assert_equal m.name, i.author.name, "Name of man should be the same after changes to replaced-child-owned instance"
+  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
index 780eabc443..e2228228a3 100644
--- a/activerecord/test/cases/associations/inner_join_association_test.rb
+++ b/activerecord/test/cases/associations/inner_join_association_test.rb
@@ -4,6 +4,7 @@ require 'models/comment'
 require 'models/author'
 require 'models/category'
 require 'models/categorization'
+require 'models/person'
 require 'models/tagging'
 require 'models/tag'
 
@@ -16,6 +17,13 @@ class InnerJoinAssociationTest < ActiveRecord::TestCase
     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)
@@ -65,21 +73,21 @@ class InnerJoinAssociationTest < ActiveRecord::TestCase
     authors_with_welcoming_post_titles = Author.calculate(:count, 'authors.id', :joins => :posts, :distinct => true, :conditions => "posts.title like 'Welcome%'")
     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?
diff --git a/activerecord/test/cases/associations/inverse_associations_test.rb b/activerecord/test/cases/associations/inverse_associations_test.rb
index 0491b2d1fa..76282213d8 100644
--- a/activerecord/test/cases/associations/inverse_associations_test.rb
+++ b/activerecord/test/cases/associations/inverse_associations_test.rb
@@ -114,7 +114,7 @@ class InverseHasOneTests < ActiveRecord::TestCase
   end
 
   def test_parent_instance_should_be_shared_with_newly_built_child
-    m = men(:gordon)
+    m = Man.find(: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"
@@ -125,7 +125,7 @@ class InverseHasOneTests < ActiveRecord::TestCase
   end
 
   def test_parent_instance_should_be_shared_with_newly_created_child
-    m = men(:gordon)
+    m = Man.find(: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"
@@ -137,40 +137,7 @@ class InverseHasOneTests < ActiveRecord::TestCase
 
   def test_parent_instance_should_be_shared_with_newly_created_child_via_bang_method
     m = Man.find(:first)
-    f = m.face.create!(: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_built_child_when_we_dont_replace_existing
-    m = Man.find(:first)
-    f = m.build_face({:description => 'haunted'}, false)
-    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_when_we_dont_replace_existing
-    m = Man.find(:first)
-    f = m.create_face({:description => 'haunted'}, false)
-    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_when_we_dont_replace_existing
-    m = Man.find(:first)
-    f = m.face.create!({:description => 'haunted'}, false)
+    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'
@@ -191,30 +158,6 @@ class InverseHasOneTests < ActiveRecord::TestCase
     assert_equal m.name, f.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_replaced_via_method_child
-    m = Man.find(:first)
-    f = Face.new(:description => 'haunted')
-    m.face.replace(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_parent_instance_should_be_shared_with_replaced_via_method_child_when_we_dont_replace_existing
-    m = Man.find(:first)
-    f = Face.new(:description => 'haunted')
-    m.face.replace(f, false)
-    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.find(:first).dirty_face }
   end
@@ -257,17 +200,6 @@ class InverseHasManyTests < ActiveRecord::TestCase
     end
   end
 
-  def test_parent_instance_should_be_shared_with_newly_built_child
-    m = men(:gordon)
-    i = m.interests.build(: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 just-built-child-owned instance"
-  end
-
   def test_parent_instance_should_be_shared_with_newly_block_style_built_child
     m = Man.find(:first)
     i = m.interests.build {|ii| ii.topic = 'Industrial Revolution Re-enactment'}
@@ -280,17 +212,6 @@ class InverseHasManyTests < ActiveRecord::TestCase
     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_child
-    m = men(:gordon)
-    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_created_via_bang_method_child
     m = Man.find(:first)
     i = m.interests.create!(:topic => 'Industrial Revolution Re-enactment')
@@ -338,18 +259,6 @@ class InverseHasManyTests < ActiveRecord::TestCase
     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_replaced_via_method_children
-    m = Man.find(:first)
-    i = Interest.new(:topic => 'Industrial Revolution Re-enactment')
-    m.interests.replace([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_trying_to_use_inverses_that_dont_exist_should_raise_an_error
     assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Man.find(:first).secret_interests }
   end
@@ -433,19 +342,6 @@ class InverseBelongsToTests < ActiveRecord::TestCase
     assert_equal f.description, m.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
-    f = faces(:trusting)
-    assert_not_nil f.man
-    m = Man.new(:name => 'Charles')
-    f.man.replace(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.find(:first).horrible_man }
   end
@@ -501,7 +397,7 @@ class InversePolymorphicBelongsToTests < ActiveRecord::TestCase
     new_man = Man.new
 
     assert_not_nil face.polymorphic_man
-    face.polymorphic_man.replace(new_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'
diff --git a/activerecord/test/cases/associations/join_model_test.rb b/activerecord/test/cases/associations/join_model_test.rb
index 2aac95a25d..543eff7d8b 100644
--- a/activerecord/test/cases/associations/join_model_test.rb
+++ b/activerecord/test/cases/associations/join_model_test.rb
@@ -13,7 +13,8 @@ require 'models/book'
 require 'models/citation'
 
 class AssociationsJoinModelTest < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  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
@@ -85,16 +86,9 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
     end
   end
 
-  def test_polymorphic_has_many_going_through_join_model_with_disabled_include
-    assert_equal tags(:general), tag = posts(:welcome).tags.add_joins_and_select.first
-    assert_queries 1 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
-    tag.author_id
+    assert_nothing_raised(NoMethodError) { tag.author_id }
   end
 
   def test_polymorphic_has_many_going_through_join_model_with_custom_foreign_key
@@ -159,7 +153,7 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
 
   def test_create_polymorphic_has_one_with_scope
     old_count = Tagging.count
-    tagging = posts(:welcome).tagging.create(:tag => tags(:misc))
+    tagging = posts(:welcome).create_tagging(:tag => tags(:misc))
     assert_equal "Post", tagging.taggable_type
     assert_equal old_count+1, Tagging.count
   end
@@ -220,7 +214,7 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
   end
 
   def test_has_many_with_piggyback
-    assert_equal "2", categories(:sti_test).authors.first.post_id.to_s
+    assert_equal "2", categories(:sti_test).authors_with_select.first.post_id.to_s
   end
 
   def test_include_has_many_through
@@ -298,6 +292,22 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
     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(:id)
+  end
+
   def test_both_scoped_and_explicit_joins_should_be_respected
     assert_nothing_raised do
       Post.send(:with_scope, :find => {:joins => "left outer join comments on comments.id = posts.id"}) do
@@ -324,11 +334,16 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
   end
 
   def test_has_many_polymorphic
-    assert_raise ActiveRecord::HasManyThroughAssociationPolymorphicError do
-      assert_equal posts(:welcome, :thinking), tags(:general).taggables
+    assert_raise ActiveRecord::HasManyThroughAssociationPolymorphicSourceError do
+      tags(:general).taggables
+    end
+
+    assert_raise ActiveRecord::HasManyThroughAssociationPolymorphicThroughError do
+      taggings(:welcome_general).things
     end
+
     assert_raise ActiveRecord::EagerLoadPolymorphicError do
-      assert_equal posts(:welcome, :thinking), tags(:general).taggings.find(:all, :include => :taggable, :conditions => 'bogus_table.column = 1')
+      tags(:general).taggings.find(:all, :include => :taggable, :conditions => 'bogus_table.column = 1')
     end
   end
 
@@ -488,6 +503,10 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
     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
@@ -496,7 +515,7 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
 
   def test_has_many_through_collection_size_uses_counter_cache_if_it_exists
     author = authors(:david)
-    author.stubs(:read_attribute).with('comments_count').returns(100)
+    author.stubs(:_read_attribute).with('comments_count').returns(100)
     assert_equal 100, author.comments.size
     assert !author.comments.loaded?
   end
diff --git a/activerecord/test/cases/associations/nested_through_associations_test.rb b/activerecord/test/cases/associations/nested_through_associations_test.rb
index db7c8b6c45..a4ac69782a 100644
--- a/activerecord/test/cases/associations/nested_through_associations_test.rb
+++ b/activerecord/test/cases/associations/nested_through_associations_test.rb
@@ -51,9 +51,19 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
   # 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
@@ -62,11 +72,6 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
     # This ensures that the polymorphism of taggings is being observed correctly
     authors = Author.joins(:tags).where('taggings.taggable_type' => 'FakeModel')
     assert authors.empty?
-
-    authors = assert_queries(5) { Author.includes(:tags).to_a }
-    assert_no_queries do
-      assert_equal [general, general], authors.first.tags
-    end
   end
 
   # has_many through
@@ -74,60 +79,69 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
   # 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
 
-    author = authors(:david)
-    assert_equal [luke, david, david], author.subscribers.order('subscribers.nick')
+  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
     )
-
-    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
 
   # has_many through
   # Source: has_one through
   # Through: has_one
   def test_has_many_through_has_one_with_has_one_through_source_reflection
-    founding = member_types(:founding)
-
-    assert_equal [founding], members(:groucho).nested_member_types
-
-    assert_includes_and_joins_equal(
-      Member.where('member_types.id' => founding.id),
-      [members(:groucho)], :nested_member_types
-    )
+    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
-    mustache = sponsors(:moustache_club_sponsor_for_groucho)
-
-    assert_equal [mustache], members(:groucho).nested_sponsors
-
-    assert_includes_and_joins_equal(
-      Member.where('sponsors.id' => mustache.id),
-      [members(:groucho)], :nested_sponsors
-    )
+    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 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
@@ -136,7 +150,18 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
 
     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
+    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
@@ -145,11 +170,6 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
     members = Member.joins(:organization_member_details).
                      where('member_details.id' => 9)
     assert members.empty?
-
-    members = assert_queries(4) { Member.includes(:organization_member_details).to_a.sort_by(&:id) }
-    assert_no_queries do
-      assert_equal [groucho_details, other_details], members.first.organization_member_details.sort_by(&:id)
-    end
   end
 
   # has_many through
@@ -160,20 +180,26 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
 
     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)
 
+    assert_no_queries 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' => groucho_details.id).order('member_details.id'),
+      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?
-
-    members = assert_queries(4) { Member.includes(:organization_member_details_2).to_a.sort_by(&:id) }
-    assert_no_queries do
-      assert_equal [groucho_details, other_details], members.first.organization_member_details_2.sort_by(&:id)
-    end
   end
 
   # has_many through
@@ -183,18 +209,24 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
     general, cooking = categories(:general), categories(:cooking)
 
     assert_equal [general, cooking], authors(:bob).post_categories.order('categories.id')
+  end
 
-    assert_includes_and_joins_equal(
-      Author.where('categories.id' => cooking.id),
-      [authors(:bob)], :post_categories
-    )
-
+  def test_has_many_through_has_many_with_has_and_belongs_to_many_source_reflection_preload
     authors = assert_queries(3) { 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
+    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
@@ -202,18 +234,24 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
     greetings, more = comments(:greetings), comments(:more_greetings)
 
     assert_equal [greetings, more], categories(:technology).post_comments.order('comments.id')
+  end
 
-    assert_includes_and_joins_equal(
-      Category.where('comments.id' => more.id).order('comments.id'),
-      [categories(:general), categories(:technology)], :post_comments
-    )
-
+  def test_has_many_through_has_and_belongs_to_many_with_has_many_source_reflection_preload
     categories = assert_queries(3) { 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
+    assert_includes_and_joins_equal(
+      Category.where('comments.id' => comments(:more_greetings).id).order('comments.id'),
+      [categories(:general), categories(:technology)], :post_comments
+    )
+  end
+
   # has_many through
   # Source: has_many through a habtm
   # Through: has_many through
@@ -221,35 +259,45 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
     greetings, more = comments(:greetings), comments(:more_greetings)
 
     assert_equal [greetings, more], authors(:bob).category_post_comments.order('comments.id')
+  end
 
-    assert_includes_and_joins_equal(
-      Author.where('comments.id' => comments(:does_it_hurt).id).order('comments.id'),
-      [authors(:david), authors(:mary)], :category_post_comments
-    )
-
+  def test_has_many_through_has_many_with_has_many_through_habtm_source_reflection_preload
     authors = assert_queries(5) { 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
+    assert_includes_and_joins_equal(
+      Author.where('comments.id' => comments(:does_it_hurt).id).order('comments.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_equal [general, general], authors(:david).tagging_tags
+    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
     )
-
-    authors = assert_queries(5) { Author.includes(:tagging_tags).to_a }
-    assert_no_queries do
-      assert_equal [general, general], authors.first.tagging_tags
-    end
   end
 
   # has_many through
@@ -260,54 +308,68 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
 
     assert_equal [welcome_general, thinking_general],
                  categorizations(:david_welcome_general).post_taggings.order('taggings.id')
+  end
 
-    assert_includes_and_joins_equal(
-      Categorization.where('taggings.id' => welcome_general.id).order('taggings.id'),
-      [categorizations(:david_welcome_general)], :post_taggings
-    )
-
+  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_equal founding, members(:groucho).nested_member_type
+    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' => founding.id),
+      Member.where('member_types.id' => member_types(:founding).id),
       [members(:groucho)], :nested_member_type
     )
-
-    members = assert_queries(4) { Member.includes(:nested_member_type).to_a.sort_by(&:id) }
-    assert_no_queries do
-      assert_equal founding, members.first.nested_member_type
-    end
   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_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_equal general, members(:groucho).club_category
+    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
     )
-
-    members = assert_queries(4) { Member.includes(:club_category).to_a.sort_by(&:id) }
-    assert_no_queries do
-      assert_equal general, members.first.club_category
-    end
   end
 
   def test_distinct_has_many_through_a_has_many_through_association_on_source_reflection
@@ -406,41 +468,49 @@ class NestedThroughAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_nested_has_many_through_with_conditions_on_through_associations
-    blue, bob = tags(:blue), authors(:bob)
-
-    assert_equal [blue], bob.misc_post_first_blue_tags
-
-    # Pointless condition to force single-query loading
-    assert_includes_and_joins_equal(
-      Author.where('tags.id = tags.id'),
-      [bob], :misc_post_first_blue_tags
-    )
+    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_source_associations
-    blue, bob = tags(:blue), authors(:bob)
-
-    assert_equal [blue], bob.misc_post_first_blue_tags_2
-
+  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'),
-      [bob], :misc_post_first_blue_tags_2
+      [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'),
+      [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
 
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
index 83c605d2bb..47b8e48582 100644
--- a/activerecord/test/cases/associations_test.rb
+++ b/activerecord/test/cases/associations_test.rb
@@ -133,25 +133,6 @@ end
 class AssociationProxyTest < ActiveRecord::TestCase
   fixtures :authors, :posts, :categorizations, :categories, :developers, :projects, :developers_projects
 
-  def test_proxy_accessors
-    welcome = posts(:welcome)
-    assert_equal  welcome, welcome.author.proxy_owner
-    assert_equal  welcome.class.reflect_on_association(:author), welcome.author.proxy_reflection
-    welcome.author.class  # force load target
-    assert_equal  welcome.author, welcome.author.proxy_target
-
-    david = authors(:david)
-    assert_equal  david, david.posts.proxy_owner
-    assert_equal  david.class.reflect_on_association(:posts), david.posts.proxy_reflection
-    david.posts.class   # force load target
-    assert_equal  david.posts, david.posts.proxy_target
-
-    assert_equal  david, david.posts_with_extension.testing_proxy_owner
-    assert_equal  david.class.reflect_on_association(:posts_with_extension), david.posts_with_extension.testing_proxy_reflection
-    david.posts_with_extension.class   # force load target
-    assert_equal  david.posts_with_extension, david.posts_with_extension.testing_proxy_target
-  end
-
   def test_push_does_not_load_target
     david = authors(:david)
 
@@ -216,37 +197,12 @@ class AssociationProxyTest < ActiveRecord::TestCase
     assert_equal post.body, "More cool stuff!"
   end
 
-  def test_failed_reload_returns_nil
-    p = setup_dangling_association
-    assert_nil p.author.reload
-  end
-
-  def test_failed_reset_returns_nil
-    p = setup_dangling_association
-    assert_nil p.author.reset
-  end
-
   def test_reload_returns_assocition
     david = developers(:david)
     assert_nothing_raised do
       assert_equal david.projects, david.projects.reload.reload
     end
   end
-
-  if RUBY_VERSION < '1.9'
-    def test_splat_does_not_invoke_to_a_on_singular_targets
-      author = posts(:welcome).author
-      author.reload.target.expects(:to_a).never
-      [*author]
-    end
-  end
-
-  def setup_dangling_association
-    josh = Author.create(:name => "Josh")
-    p = Post.create(:title => "New on Edge", :body => "More cool stuff!", :author => josh)
-    josh.destroy
-    p
-  end
 end
 
 class OverridingAssociationsTest < ActiveRecord::TestCase
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..d0a9028264
--- /dev/null
+++ b/activerecord/test/cases/attribute_methods/read_test.rb
@@ -0,0 +1,61 @@
+require "cases/helper"
+
+module ActiveRecord
+  module AttributeMethods
+    class ReadTest < ActiveRecord::TestCase
+      class FakeColumn < Struct.new(:name)
+        def type_cast_code(var)
+          var
+        end
+
+        def type; :integer; end
+      end
+
+      def setup
+        @klass = Class.new do
+          include ActiveRecord::AttributeMethods
+          include ActiveRecord::AttributeMethods::Read
+
+          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
+
+          def self.serialized_attributes; {}; 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(!@klass.attribute_methods_generated?, 'attribute_methods_generated?')
+        @klass.define_attribute_methods
+        assert(@klass.attribute_methods_generated?, 'attribute_methods_generated?')
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
index 8214815bde..dfacf58da8 100644
--- a/activerecord/test/cases/attribute_methods_test.rb
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -8,6 +8,7 @@ require 'models/topic'
 require 'models/company'
 require 'models/category'
 require 'models/reply'
+require 'models/contact'
 
 class AttributeMethodsTest < ActiveRecord::TestCase
   fixtures :topics, :developers, :companies, :computers
@@ -105,7 +106,7 @@ class AttributeMethodsTest < ActiveRecord::TestCase
 
   def test_read_attributes_before_type_cast
     category = Category.new({:name=>"Test categoty", :type => nil})
-    category_attrs = {"name"=>"Test categoty", "type" => nil, "categorizations_count" => nil}
+    category_attrs = {"name"=>"Test categoty", "id" => nil, "type" => nil, "categorizations_count" => nil}
     assert_equal category_attrs , category.attributes_before_type_cast
   end
 
@@ -116,24 +117,23 @@ class AttributeMethodsTest < ActiveRecord::TestCase
     end
   end
 
-  unless current_adapter?(:Mysql2Adapter)
-    def test_read_attributes_before_type_cast_on_datetime
-      developer = Developer.find(:first)
-      # Oracle adapter returns Time before type cast
-      unless current_adapter?(:OracleAdapter)
-        assert_equal developer.created_at.to_s(:db) , developer.attributes_before_type_cast["created_at"].to_s
-      else
-        assert_equal developer.created_at.to_s(:db) , developer.attributes_before_type_cast["created_at"].to_s(:db)
+  def test_read_attributes_before_type_cast_on_datetime
+    developer = Developer.find(:first)
+    if current_adapter?(:Mysql2Adapter, :OracleAdapter)
+      # Mysql2 and Oracle adapters keep the value in Time instance
+      assert_equal developer.created_at.to_s(:db), developer.attributes_before_type_cast["created_at"].to_s(:db)
+    else
+      assert_equal developer.created_at.to_s(:db), developer.attributes_before_type_cast["created_at"].to_s
+    end
 
-        developer.created_at = "345643456"
-        assert_equal developer.created_at_before_type_cast, "345643456"
-        assert_equal developer.created_at, nil
+    developer.created_at = "345643456"
 
-        developer.created_at = "2010-03-21 21:23:32"
-        assert_equal developer.created_at_before_type_cast.to_s, "2010-03-21 21:23:32"
-        assert_equal developer.created_at, Time.parse("2010-03-21 21:23:32")
-      end
-    end
+    assert_equal developer.created_at_before_type_cast, "345643456"
+    assert_equal developer.created_at, nil
+
+    developer.created_at = "2010-03-21 21:23:32"
+    assert_equal developer.created_at_before_type_cast, "2010-03-21 21:23:32"
+    assert_equal developer.created_at, Time.parse("2010-03-21 21:23:32")
   end
 
   def test_hash_content
@@ -247,6 +247,12 @@ class AttributeMethodsTest < ActiveRecord::TestCase
     # puts ""
   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?
@@ -455,6 +461,14 @@ class AttributeMethodsTest < ActiveRecord::TestCase
     end
   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_time_attributes_are_retrieved_in_current_time_zone
     in_time_zone "Pacific Time (US & Canada)" do
       utc_time = Time.utc(2008, 1, 1)
@@ -596,6 +610,10 @@ class AttributeMethodsTest < ActiveRecord::TestCase
     Object.send(:undef_method, :title) # remove test method from object
   end
 
+  def test_list_of_serialized_attributes
+    assert_equal %w(content), Topic.serialized_attributes.keys
+    assert_equal %w(preferences), Contact.serialized_attributes.keys
+  end
 
   private
   def cached_columns
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
index fbf7121468..8f55b7ebe6 100644
--- a/activerecord/test/cases/autosave_association_test.rb
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -21,19 +21,19 @@ require 'models/eye'
 
 class TestAutosaveAssociationsInGeneral < ActiveRecord::TestCase
   def test_autosave_should_be_a_valid_option_for_has_one
-    assert base.valid_keys_for_has_one_association.include?(:autosave)
+    assert ActiveRecord::Associations::Builder::HasOne.valid_options.include?(:autosave)
   end
 
   def test_autosave_should_be_a_valid_option_for_belongs_to
-    assert base.valid_keys_for_belongs_to_association.include?(:autosave)
+    assert ActiveRecord::Associations::Builder::BelongsTo.valid_options.include?(:autosave)
   end
 
   def test_autosave_should_be_a_valid_option_for_has_many
-    assert base.valid_keys_for_has_many_association.include?(:autosave)
+    assert ActiveRecord::Associations::Builder::HasMany.valid_options.include?(:autosave)
   end
 
   def test_autosave_should_be_a_valid_option_for_has_and_belongs_to_many
-    assert base.valid_keys_for_has_and_belongs_to_many_association.include?(:autosave)
+    assert ActiveRecord::Associations::Builder::HasAndBelongsToMany.valid_options.include?(:autosave)
   end
 
   def test_should_not_add_the_same_callbacks_multiple_times_for_has_one
@@ -90,7 +90,7 @@ class TestDefaultAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCas
     firm = Firm.find(:first)
     assert firm.valid?
 
-    firm.account = Account.new
+    firm.build_account
 
     assert !firm.account.valid?
     assert !firm.valid?
@@ -102,7 +102,7 @@ class TestDefaultAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCas
     firm = Firm.find(:first)
     assert firm.valid?
 
-    firm.unvalidated_account = Account.new
+    firm.build_unvalidated_account
 
     assert !firm.unvalidated_account.valid?
     assert firm.valid?
@@ -112,7 +112,7 @@ class TestDefaultAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCas
   def test_build_before_child_saved
     firm = Firm.find(1)
 
-    account = firm.account.build("credit_limit" => 1000)
+    account = firm.build_account("credit_limit" => 1000)
     assert_equal account, firm.account
     assert !account.persisted?
     assert firm.save
@@ -340,6 +340,13 @@ class TestDefaultAutosaveAssociationOnABelongsToAssociation < ActiveRecord::Test
     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.find(:first)
+    apple = client.build_firm(:name => "Apple")
+    client.save!
+    assert_no_queries { assert_equal apple, client.firm }
+  end
 end
 
 class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCase
@@ -565,7 +572,7 @@ class TestDefaultAutosaveAssociationOnNewRecord < ActiveRecord::TestCase
 end
 
 class TestDestroyAsPartOfAutosaveAssociation < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
@@ -578,7 +585,7 @@ class TestDestroyAsPartOfAutosaveAssociation < ActiveRecord::TestCase
     @pirate.ship.mark_for_destruction
 
     assert !@pirate.reload.marked_for_destruction?
-    assert !@pirate.ship.marked_for_destruction?
+    assert !@pirate.ship.reload.marked_for_destruction?
   end
 
   # has_one
@@ -667,119 +674,227 @@ class TestDestroyAsPartOfAutosaveAssociation < ActiveRecord::TestCase
       end
     end
 
+    @ship.pirate.catchphrase = "Changed Catchphrase"
+
     assert_raise(RuntimeError) { assert !@ship.save }
     assert_not_nil @ship.reload.pirate
   end
 
-  # has_many & has_and_belongs_to
-  %w{ parrots birds }.each do |association_name|
-    define_method("test_should_destroy_#{association_name}_as_part_of_the_save_transaction_if_they_were_marked_for_destroyal") do
-      2.times { |i| @pirate.send(association_name).create!(:name => "#{association_name}_#{i}") }
+  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.send(association_name).any? { |child| child.marked_for_destruction? }
+    assert !@pirate.birds.any? { |child| child.marked_for_destruction? }
 
-      @pirate.send(association_name).each { |child| child.mark_for_destruction }
-      klass = @pirate.send(association_name).first.class
-      ids = @pirate.send(association_name).map(&:id)
+    @pirate.birds.each { |child| child.mark_for_destruction }
+    klass = @pirate.birds.first.class
+    ids = @pirate.birds.map(&:id)
 
-      assert @pirate.send(association_name).all? { |child| child.marked_for_destruction? }
-      ids.each { |id| assert klass.find_by_id(id) }
+    assert @pirate.birds.all? { |child| child.marked_for_destruction? }
+    ids.each { |id| assert klass.find_by_id(id) }
 
-      @pirate.save
-      assert @pirate.reload.send(association_name).empty?
-      ids.each { |id| assert_nil 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_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
 
-    define_method("test_should_skip_validation_on_the_#{association_name}_association_if_marked_for_destruction") do
-      2.times { |i| @pirate.send(association_name).create!(:name => "#{association_name}_#{i}") }
-      children = @pirate.send(association_name)
+  def test_should_skip_validation_on_has_many_if_destroyed
+    @pirate.birds.create!(:name => "birds_1")
 
-      children.each { |child| child.name = '' }
-      assert !@pirate.valid?
+    @pirate.birds.each { |bird| bird.name = '' }
+    assert !@pirate.valid?
 
-      children.each do |child|
-        child.mark_for_destruction
-        child.expects(:valid?).never
+    @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
-      assert_difference("#{association_name.classify}.count", -2) { @pirate.save! }
     end
 
-    define_method("test_should_skip_validation_on_the_#{association_name}_association_if_destroyed") do
-      @pirate.send(association_name).create!(:name => "#{association_name}_1")
-      children = @pirate.send(association_name)
+    assert_raise(RuntimeError) { assert !@pirate.save }
+    assert_equal before, @pirate.reload.birds
+  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")
 
-      children.each { |child| child.name = '' }
-      assert !@pirate.valid?
+      expected = [
+        "before_adding_#{callback_type}_bird_<new>",
+        "after_adding_#{callback_type}_bird_<new>"
+      ]
 
-      children.each { |child| child.destroy }
-      assert @pirate.valid?
+      assert_equal expected, pirate.ship_log
     end
 
-    define_method("test_a_child_marked_for_destruction_should_not_be_destroyed_twice_while_saving_#{association_name}") do
-      @pirate.send(association_name).create!(:name => "#{association_name}_1")
-      children = @pirate.send(association_name)
+    define_method("test_should_run_remove_callback_#{callback_type}s_for_has_many") do
+      association_name_with_callbacks = "birds_with_#{callback_type}_callbacks"
 
-      children.each { |child| child.mark_for_destruction }
-      assert @pirate.save
-      children.each { |child| child.expects(:destroy).never }
-      assert @pirate.save
+      @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
 
-    define_method("test_should_rollback_destructions_if_an_exception_occurred_while_saving_#{association_name}") do
-      2.times { |i| @pirate.send(association_name).create!(:name => "#{association_name}_#{i}") }
-      before = @pirate.send(association_name).map { |c| c.mark_for_destruction ; c }
+  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}") }
 
-      # Stub the destroy method of the the second child to raise an exception
-      class << before.last
-        def destroy(*args)
-          super
-          raise 'Oh noes!'
-        end
-      end
+    assert !@pirate.parrots.any? { |parrot| parrot.marked_for_destruction? }
+    @pirate.parrots.each { |parrot| parrot.mark_for_destruction }
 
-      assert_raise(RuntimeError) { assert !@pirate.save }
-      assert_equal before, @pirate.reload.send(association_name)
+    assert_no_difference "Parrot.count" do
+      @pirate.save
     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_#{association_name}") do
-        association_name_with_callbacks = "#{association_name}_with_#{callback_type}_callbacks"
+    assert @pirate.reload.parrots.empty?
 
-        pirate = Pirate.new(:catchphrase => "Arr")
-        pirate.send(association_name_with_callbacks).build(:name => "Crowe the One-Eyed")
+    join_records = Pirate.connection.select_all("SELECT * FROM parrots_pirates WHERE pirate_id = #{@pirate.id}")
+    assert join_records.empty?
+  end
 
-        expected = [
-          "before_adding_#{callback_type}_#{association_name.singularize}_<new>",
-          "after_adding_#{callback_type}_#{association_name.singularize}_<new>"
-        ]
+  def test_should_skip_validation_on_habtm_if_marked_for_destruction
+    2.times { |i| @pirate.parrots.create!(:name => "parrots_#{i}") }
 
-        assert_equal expected, pirate.ship_log
-      end
+    @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")
 
-      define_method("test_should_run_remove_callback_#{callback_type}s_for_#{association_name}") do
-        association_name_with_callbacks = "#{association_name}_with_#{callback_type}_callbacks"
+    @pirate.parrots.each { |parrot| parrot.name = '' }
+    assert !@pirate.valid?
 
-        @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.parrots.each { |parrot| parrot.destroy }
+    assert @pirate.valid?
+  end
 
-        @pirate.ship_log.clear
-        @pirate.save
+  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
+
+    assert_no_queries do
+      assert @pirate.save
+    end
+  end
 
-        expected = [
-          "before_removing_#{callback_type}_#{association_name.singularize}_#{child_id}",
-          "after_removing_#{callback_type}_#{association_name.singularize}_#{child_id}"
-        ]
+  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 }
 
-        assert_equal expected, @pirate.ship_log
+    class << @pirate.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
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
@@ -850,7 +965,10 @@ class TestAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCase
     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
+      expected = ActiveRecord::IdentityMap.enabled? ?
+        [nil, nil, '', ''] :
+        [nil, nil, nil, nil]
+      assert_equal expected, values
     else
       assert_equal ['', '', '', ''], values
     end
@@ -899,7 +1017,7 @@ class TestAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCase
 end
 
 class TestAutosaveAssociationOnABelongsToAssociation < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @ship = Ship.create(:name => 'Nights Dirty Lightning')
@@ -945,7 +1063,8 @@ class TestAutosaveAssociationOnABelongsToAssociation < ActiveRecord::TestCase
     @ship.save(:validate => false)
     # Oracle saves empty string as NULL
     if current_adapter?(:OracleAdapter)
-      assert_equal [nil, nil], [@ship.reload.name, @ship.pirate.catchphrase]
+      expected = ActiveRecord::IdentityMap.enabled? ?  [nil, ''] : [nil, nil]
+      assert_equal expected, [@ship.reload.name, @ship.pirate.catchphrase]
     else
       assert_equal ['', ''], [@ship.reload.name, @ship.pirate.catchphrase]
     end
@@ -1146,7 +1265,7 @@ module AutosaveAssociationOnACollectionAssociationTests
 end
 
 class TestAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @association_name = :birds
@@ -1160,7 +1279,7 @@ class TestAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCase
 end
 
 class TestAutosaveAssociationOnAHasAndBelongsToManyAssociation < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @association_name = :parrots
@@ -1175,7 +1294,7 @@ class TestAutosaveAssociationOnAHasAndBelongsToManyAssociation < ActiveRecord::T
 end
 
 class TestAutosaveAssociationValidationsOnAHasManyAssociation < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
@@ -1191,11 +1310,12 @@ class TestAutosaveAssociationValidationsOnAHasManyAssociation < ActiveRecord::Te
 end
 
 class TestAutosaveAssociationValidationsOnAHasOneAssociation < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @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
@@ -1204,7 +1324,7 @@ class TestAutosaveAssociationValidationsOnAHasOneAssociation < ActiveRecord::Tes
     assert !@pirate.valid?
   end
 
-  test "should not automatically validate associations without :validate => true" do
+  test "should not automatically asd validate associations without :validate => true" do
     assert @pirate.valid?
     @pirate.non_validated_ship.name = ''
     assert @pirate.valid?
@@ -1212,7 +1332,7 @@ class TestAutosaveAssociationValidationsOnAHasOneAssociation < ActiveRecord::Tes
 end
 
 class TestAutosaveAssociationValidationsOnABelongsToAssociation < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
@@ -1232,7 +1352,7 @@ class TestAutosaveAssociationValidationsOnABelongsToAssociation < ActiveRecord::
 end
 
 class TestAutosaveAssociationValidationsOnAHABTMAssociation < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @pirate = Pirate.create(:catchphrase => "Don' botharrr talkin' like one, savvy?")
@@ -1254,7 +1374,7 @@ class TestAutosaveAssociationValidationsOnAHABTMAssociation < ActiveRecord::Test
 end
 
 class TestAutosaveAssociationValidationMethodsGeneration < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @pirate = Pirate.new
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 86d4a90fc4..b62b5003e4 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -19,6 +19,8 @@ require 'models/minimalistic'
 require 'models/warehouse_thing'
 require 'models/parrot'
 require 'models/loose_person'
+require 'models/edge'
+require 'models/joke'
 require 'rexml/document'
 require 'active_support/core_ext/exception'
 
@@ -48,6 +50,57 @@ class Boolean < ActiveRecord::Base; end
 class BasicsTest < ActiveRecord::TestCase
   fixtures :topics, :companies, :developers, :projects, :computers, :accounts, :minimalistics, 'warehouse-things', :authors, :categorizations, :categories, :posts
 
+  def test_columns_should_obey_set_primary_key
+    pk = Subscriber.columns.find { |x| x.name == 'nick' }
+    assert pk.primary, '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_nothing_raised do
+        Topic.limit("1,2").all
+      end
+    end
+  end
+
+  def test_limit_without_comma
+    assert_nothing_raised do
+      assert_equal 1, Topic.limit("1").all.length
+    end
+
+    assert_nothing_raised do
+      assert_equal 1, Topic.limit(1).all.length
+    end
+  end
+
+  def test_invalid_limit
+    assert_raises(ArgumentError) do
+      Topic.limit("asdfadf").all
+    end
+  end
+
+  def test_limit_should_sanitize_sql_injection_for_limit_without_comas
+    assert_raises(ArgumentError) do
+      Topic.limit("1 select * from schema").all
+    end
+  end
+
+  def test_limit_should_sanitize_sql_injection_for_limit_with_comas
+    assert_raises(ArgumentError) do
+      Topic.limit("1, 7 procedure help()").all
+    end
+  end
+
+  unless current_adapter?(:MysqlAdapter) || current_adapter?(:Mysql2Adapter)
+    def test_limit_should_allow_sql_literal
+      assert_equal 1, Topic.limit(Arel.sql('2-1')).all.length
+    end
+  end
+
   def test_select_symbol
     topic_ids = Topic.select(:id).map(&:id).sort
     assert_equal Topic.find(:all).map(&:id).sort, topic_ids
@@ -81,6 +134,7 @@ class BasicsTest < ActiveRecord::TestCase
     fakepool = Class.new(Struct.new(:spec)) {
       def with_connection; yield self; end
       def connection_pool; self; end
+      def table_exists?(name); false; end
       def quote_table_name(*args); raise "lol quote_table_name"; end
     }
 
@@ -698,7 +752,7 @@ class BasicsTest < ActiveRecord::TestCase
 
     duped_topic.reload
     # FIXME: I think this is poor behavior, and will fix it with #5686
-    assert_equal({'a' => 'c'}.to_s, duped_topic.title)
+    assert_equal({'a' => 'c'}.to_yaml, duped_topic.title)
   end
 
   def test_dup_with_aggregate_of_same_name_as_attribute
@@ -997,6 +1051,25 @@ class BasicsTest < ActiveRecord::TestCase
     Topic.serialize(: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"]
+  ensure
+    Topic.serialize(:content)
+  end
+
+  def test_serialized_no_default_class_for_object
+    topic = Topic.new
+    assert_nil topic.content
+  end
+
   def test_serialized_boolean_value_true
     Topic.serialize(:content)
     topic = Topic.new(:content => true)
@@ -1013,6 +1086,52 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal topic.content, false
   end
 
+  def test_serialize_with_coder
+    coder = Class.new {
+      # Identity
+      def load(thing)
+        thing
+      end
+
+      # base 64
+      def dump(thing)
+        [thing].pack('m')
+      end
+    }.new
+
+    Topic.serialize(:content, coder)
+    s = 'hello world'
+    topic = Topic.new(:content => s)
+    assert topic.save
+    topic = topic.reload
+    assert_equal [s].pack('m'), topic.content
+  ensure
+    Topic.serialize(:content)
+  end
+
+  def test_serialize_with_bcrypt_coder
+    crypt_coder = Class.new {
+      def load(thing)
+        return unless thing
+        BCrypt::Password.new thing
+      end
+
+      def dump(thing)
+        BCrypt::Password.create(thing).to_s
+      end
+    }.new
+
+    Topic.serialize(:content, crypt_coder)
+    password = 'password'
+    topic = Topic.new(:content => password)
+    assert topic.save
+    topic = topic.reload
+    assert_kind_of BCrypt::Password, topic.content
+    assert_equal(true, topic.content == password, 'password should equal')
+  ensure
+    Topic.serialize(:content)
+  end
+
   def test_quote
     author_name = "\\ \001 ' \n \\n \""
     topic = Topic.create('author_name' => author_name)
@@ -1068,9 +1187,14 @@ class BasicsTest < ActiveRecord::TestCase
   end
 
   def test_define_attr_method_with_block
-    k = Class.new( ActiveRecord::Base )
-    k.send(:define_attr_method, :primary_key) { "sys_" + original_primary_key }
-    assert_equal "sys_id", k.primary_key
+    k = Class.new( ActiveRecord::Base ) do
+      class << self
+        attr_accessor :foo_key
+      end
+    end
+    k.foo_key = "id"
+    k.send(:define_attr_method, :foo_key) { "sys_" + original_foo_key }
+    assert_equal "sys_id", k.foo_key
   end
 
   def test_set_table_name_with_value
@@ -1081,6 +1205,16 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal "bar", k.table_name
   end
 
+  def test_switching_between_table_name
+    assert_difference("GoodJoke.count") do
+      Joke.set_table_name "cold_jokes"
+      Joke.create
+
+      Joke.set_table_name "funny_jokes"
+      Joke.create
+    end
+  end
+
   def test_quoted_table_name_after_set_table_name
     klass = Class.new(ActiveRecord::Base)
 
@@ -1109,6 +1243,7 @@ class BasicsTest < ActiveRecord::TestCase
 
   def test_set_primary_key_with_block
     k = Class.new( ActiveRecord::Base )
+    k.primary_key = 'id'
     k.set_primary_key { "sys_" + original_primary_key }
     assert_equal "sys_id", k.primary_key
   end
@@ -1161,12 +1296,6 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal res6, res7
   end
 
-  def test_interpolate_sql
-    assert_nothing_raised { Category.new.send(:interpolate_sql, 'foo@bar') }
-    assert_nothing_raised { Category.new.send(:interpolate_sql, 'foo bar) baz') }
-    assert_nothing_raised { Category.new.send(:interpolate_sql, 'foo bar} baz') }
-  end
-
   def test_scoped_find_conditions
     scoped_developers = Developer.send(:with_scope, :find => { :conditions => 'salary > 90000' }) do
       Developer.find(:all, :conditions => 'id < 5')
@@ -1477,6 +1606,14 @@ class BasicsTest < ActiveRecord::TestCase
     end
   end
 
+  def test_clear_cache!
+    # preheat cache
+    c1 = Post.columns
+    ActiveRecord::Base.clear_cache!
+    c2 = Post.columns
+    assert_not_equal c1, c2
+  end
+
   def test_default_scope_is_reset
     Object.const_set :UnloadablePost, Class.new(ActiveRecord::Base)
     UnloadablePost.table_name = 'posts'
@@ -1492,4 +1629,11 @@ class BasicsTest < ActiveRecord::TestCase
   ensure
     Object.class_eval{ remove_const :UnloadablePost } if defined?(UnloadablePost)
   end
+
+  def test_marshal_round_trip
+    expected = posts(:welcome)
+    actual   = Marshal.load(Marshal.dump(expected))
+
+    assert_equal expected.attributes, actual.attributes
+  end
 end
diff --git a/activerecord/test/cases/batches_test.rb b/activerecord/test/cases/batches_test.rb
index 9e72ac4250..dc0e0da4c5 100644
--- a/activerecord/test/cases/batches_test.rb
+++ b/activerecord/test/cases/batches_test.rb
@@ -7,6 +7,7 @@ class EachTest < ActiveRecord::TestCase
   def setup
     @posts = Post.order("id asc")
     @total = Post.count
+    Post.count('id') # preheat arel's table cache
   end
 
   def test_each_should_excecute_one_query_per_batch
diff --git a/activerecord/test/cases/bind_parameter_test.rb b/activerecord/test/cases/bind_parameter_test.rb
new file mode 100644
index 0000000000..19383bb06b
--- /dev/null
+++ b/activerecord/test/cases/bind_parameter_test.rb
@@ -0,0 +1,90 @@
+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
+      @listener   = LogListener.new
+      @pk         = Topic.columns.find { |c| c.primary }
+      ActiveSupport::Notifications.subscribe('sql.active_record', @listener)
+    end
+
+    def teardown
+      ActiveSupport::Notifications.unsubscribe(@listener)
+    end
+
+    def test_binds_are_logged
+      # FIXME: use skip with minitest
+      return unless @connection.supports_statement_cache?
+
+      sub   = @connection.substitute_for(@pk, [])
+      binds = [[@pk, 1]]
+      sql   = "select * from topics where id = #{sub}"
+
+      @connection.exec_query(sql, 'SQL', binds)
+
+      message = @listener.calls.find { |args| args[4][:sql] == sql }
+      assert_equal binds, message[4][:binds]
+    end
+
+    def test_find_one_uses_binds
+      # FIXME: use skip with minitest
+      return unless @connection.supports_statement_cache?
+
+      Topic.find(1)
+      binds = [[@pk, 1]]
+      message = @listener.calls.find { |args| args[4][:binds] == binds }
+      assert message, 'expected a message with binds'
+    end
+
+    def test_logs_bind_vars
+      # FIXME: use skip with minitest
+      return unless @connection.supports_statement_cache?
+
+      pk = Topic.columns.find { |x| x.primary }
+
+      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
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index 5cb8485b4b..caf07a7357 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -23,6 +23,17 @@ class CalculationsTest < ActiveRecord::TestCase
     assert_equal 53.0, value
   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
+    Account.connection.stubs :select_value => 3
+    value = Account.average(:id)
+    assert_equal 3, value
+  end
+
   def test_should_return_nil_as_average
     assert_nil NumericData.average(:bank_balance)
   end
@@ -98,6 +109,36 @@ class CalculationsTest < ActiveRecord::TestCase
     assert_equal [2, 6], c.keys.compact
   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_offset_without_limit_removes_offset
+    queries = assert_sql { Account.offset(1).count }
+    assert_equal 1, queries.length
+    assert_no_match(/LIMIT/, queries.first)
+    assert_no_match(/OFFSET/, queries.first)
+  end
+
+  def test_limit_without_offset_removes_limit
+    queries = assert_sql { Account.limit(1).count }
+    assert_equal 1, queries.length
+    assert_no_match(/LIMIT/, queries.first)
+    assert_no_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_should_group_by_summed_field_having_condition
     c = Account.sum(:credit_limit, :group => :firm_id,
                                    :having => 'sum(credit_limit) > 50')
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..c7dcc21809
--- /dev/null
+++ b/activerecord/test/cases/coders/yaml_column_test.rb
@@ -0,0 +1,46 @@
+
+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
+        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_swallows_yaml_exceptions
+        coder = YAMLColumn.new
+        bad_yaml = '--- {'
+        assert_equal bad_yaml, coder.load(bad_yaml)
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/column_definition_test.rb b/activerecord/test/cases/column_definition_test.rb
index cc6a6b44f2..d1dddd4c2c 100644
--- a/activerecord/test/cases/column_definition_test.rb
+++ b/activerecord/test/cases/column_definition_test.rb
@@ -1,121 +1,145 @@
 require "cases/helper"
 
-class ColumnDefinitionTest < ActiveRecord::TestCase
-  def setup
-    @adapter = ActiveRecord::ConnectionAdapters::AbstractAdapter.new(nil)
-    def @adapter.native_database_types
-      {:string => "varchar"}
-    end
-  end
+module ActiveRecord
+  module ConnectionAdapters
+    class ColumnDefinitionTest < ActiveRecord::TestCase
+      def setup
+        @adapter = AbstractAdapter.new(nil)
+        def @adapter.native_database_types
+          {:string => "varchar"}
+        end
+      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 = ActiveRecord::ConnectionAdapters::Column.new("title", nil, "varchar(20)")
-    column_def = ActiveRecord::ConnectionAdapters::ColumnDefinition.new(
-      @adapter, column.name, "string",
-      column.limit, column.precision, column.scale, column.default, column.null)
-    assert_equal "title varchar(20)", column_def.to_sql
-  end
+      def test_can_set_coder
+        column = Column.new("title", nil, "varchar(20)")
+        column.coder = YAML
+        assert_equal YAML, column.coder
+      end
 
-  def test_should_include_default_clause_when_default_is_present
-    column = ActiveRecord::ConnectionAdapters::Column.new("title", "Hello", "varchar(20)")
-    column_def = ActiveRecord::ConnectionAdapters::ColumnDefinition.new(
-      @adapter, column.name, "string",
-      column.limit, column.precision, column.scale, column.default, column.null)
-    assert_equal %Q{title varchar(20) DEFAULT 'Hello'}, column_def.to_sql
-  end
+      def test_encoded?
+        column = Column.new("title", nil, "varchar(20)")
+        assert !column.encoded?
 
-  def test_should_specify_not_null_if_null_option_is_false
-    column = ActiveRecord::ConnectionAdapters::Column.new("title", "Hello", "varchar(20)", false)
-    column_def = ActiveRecord::ConnectionAdapters::ColumnDefinition.new(
-      @adapter, column.name, "string",
-      column.limit, column.precision, column.scale, column.default, column.null)
-    assert_equal %Q{title varchar(20) DEFAULT 'Hello' NOT NULL}, column_def.to_sql
-  end
+        column.coder = YAML
+        assert column.encoded?
+      end
 
-  if current_adapter?(:MysqlAdapter)
-    def test_should_set_default_for_mysql_binary_data_types
-      binary_column = ActiveRecord::ConnectionAdapters::MysqlColumn.new("title", "a", "binary(1)")
-      assert_equal "a", binary_column.default
+      def test_type_case_coded_column
+        column = Column.new("title", nil, "varchar(20)")
+        column.coder = YAML
+        assert_equal "hello", column.type_cast("--- hello")
+      end
 
-      varbinary_column = ActiveRecord::ConnectionAdapters::MysqlColumn.new("title", "a", "varbinary(1)")
-      assert_equal "a", varbinary_column.default
-    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, "varchar(20)")
+        column_def = ColumnDefinition.new(
+          @adapter, column.name, "string",
+          column.limit, column.precision, column.scale, column.default, column.null)
+          assert_equal "title varchar(20)", column_def.to_sql
+      end
 
-    def test_should_not_set_default_for_blob_and_text_data_types
-      assert_raise ArgumentError do
-        ActiveRecord::ConnectionAdapters::MysqlColumn.new("title", "a", "blob")
+      def test_should_include_default_clause_when_default_is_present
+        column = Column.new("title", "Hello", "varchar(20)")
+        column_def = ColumnDefinition.new(
+          @adapter, column.name, "string",
+          column.limit, column.precision, column.scale, column.default, column.null)
+          assert_equal %Q{title varchar(20) DEFAULT 'Hello'}, column_def.to_sql
       end
 
-      assert_raise ArgumentError do
-        ActiveRecord::ConnectionAdapters::MysqlColumn.new("title", "Hello", "text")
+      def test_should_specify_not_null_if_null_option_is_false
+        column = Column.new("title", "Hello", "varchar(20)", false)
+        column_def = ColumnDefinition.new(
+          @adapter, column.name, "string",
+          column.limit, column.precision, column.scale, column.default, column.null)
+          assert_equal %Q{title varchar(20) DEFAULT 'Hello' NOT NULL}, column_def.to_sql
       end
 
-      text_column = ActiveRecord::ConnectionAdapters::MysqlColumn.new("title", nil, "text")
-      assert_equal nil, text_column.default
+      if current_adapter?(:MysqlAdapter)
+        def test_should_set_default_for_mysql_binary_data_types
+          binary_column = MysqlColumn.new("title", "a", "binary(1)")
+          assert_equal "a", binary_column.default
 
-      not_null_text_column = ActiveRecord::ConnectionAdapters::MysqlColumn.new("title", nil, "text", false)
-      assert_equal "", not_null_text_column.default
-    end
+          varbinary_column = MysqlColumn.new("title", "a", "varbinary(1)")
+          assert_equal "a", varbinary_column.default
+        end
 
-    def test_has_default_should_return_false_for_blog_and_test_data_types
-      blob_column = ActiveRecord::ConnectionAdapters::MysqlColumn.new("title", nil, "blob")
-      assert !blob_column.has_default?
+        def test_should_not_set_default_for_blob_and_text_data_types
+          assert_raise ArgumentError do
+            MysqlColumn.new("title", "a", "blob")
+          end
 
-      text_column = ActiveRecord::ConnectionAdapters::MysqlColumn.new("title", nil, "text")
-      assert !text_column.has_default?
-    end
-  end
+          assert_raise ArgumentError do
+            MysqlColumn.new("title", "Hello", "text")
+          end
 
-  if current_adapter?(:Mysql2Adapter)
-    def test_should_set_default_for_mysql_binary_data_types
-      binary_column = ActiveRecord::ConnectionAdapters::Mysql2Column.new("title", "a", "binary(1)")
-      assert_equal "a", binary_column.default
+          text_column = MysqlColumn.new("title", nil, "text")
+          assert_equal nil, text_column.default
 
-      varbinary_column = ActiveRecord::ConnectionAdapters::Mysql2Column.new("title", "a", "varbinary(1)")
-      assert_equal "a", varbinary_column.default
-    end
+          not_null_text_column = MysqlColumn.new("title", nil, "text", false)
+          assert_equal "", not_null_text_column.default
+        end
 
-    def test_should_not_set_default_for_blob_and_text_data_types
-      assert_raise ArgumentError do
-        ActiveRecord::ConnectionAdapters::Mysql2Column.new("title", "a", "blob")
-      end
+        def test_has_default_should_return_false_for_blog_and_test_data_types
+          blob_column = MysqlColumn.new("title", nil, "blob")
+          assert !blob_column.has_default?
 
-      assert_raise ArgumentError do
-        ActiveRecord::ConnectionAdapters::Mysql2Column.new("title", "Hello", "text")
+          text_column = MysqlColumn.new("title", nil, "text")
+          assert !text_column.has_default?
+        end
       end
 
-      text_column = ActiveRecord::ConnectionAdapters::Mysql2Column.new("title", nil, "text")
-      assert_equal nil, text_column.default
+      if current_adapter?(:Mysql2Adapter)
+        def test_should_set_default_for_mysql_binary_data_types
+          binary_column = Mysql2Column.new("title", "a", "binary(1)")
+          assert_equal "a", binary_column.default
 
-      not_null_text_column = ActiveRecord::ConnectionAdapters::Mysql2Column.new("title", nil, "text", false)
-      assert_equal "", not_null_text_column.default
-    end
+          varbinary_column = Mysql2Column.new("title", "a", "varbinary(1)")
+          assert_equal "a", varbinary_column.default
+        end
 
-    def test_has_default_should_return_false_for_blog_and_test_data_types
-      blob_column = ActiveRecord::ConnectionAdapters::Mysql2Column.new("title", nil, "blob")
-      assert !blob_column.has_default?
+        def test_should_not_set_default_for_blob_and_text_data_types
+          assert_raise ArgumentError do
+            Mysql2Column.new("title", "a", "blob")
+          end
 
-      text_column = ActiveRecord::ConnectionAdapters::Mysql2Column.new("title", nil, "text")
-      assert !text_column.has_default?
-    end
-  end
+          assert_raise ArgumentError do
+            Mysql2Column.new("title", "Hello", "text")
+          end
 
-  if current_adapter?(:PostgreSQLAdapter)
-    def test_bigint_column_should_map_to_integer
-      bigint_column = ActiveRecord::ConnectionAdapters::PostgreSQLColumn.new('number', nil, "bigint")
-      assert_equal :integer, bigint_column.type
-    end
+          text_column = Mysql2Column.new("title", nil, "text")
+          assert_equal nil, text_column.default
 
-    def test_smallint_column_should_map_to_integer
-      smallint_column = ActiveRecord::ConnectionAdapters::PostgreSQLColumn.new('number', nil, "smallint")
-      assert_equal :integer, smallint_column.type
-    end
+          not_null_text_column = Mysql2Column.new("title", nil, "text", false)
+          assert_equal "", not_null_text_column.default
+        end
+
+        def test_has_default_should_return_false_for_blog_and_test_data_types
+          blob_column = Mysql2Column.new("title", nil, "blob")
+          assert !blob_column.has_default?
 
-    def test_uuid_column_should_map_to_string
-      uuid_column = ActiveRecord::ConnectionAdapters::PostgreSQLColumn.new('unique_id', nil, "uuid")
-      assert_equal :string, uuid_column.type
+          text_column = Mysql2Column.new("title", nil, "text")
+          assert !text_column.has_default?
+        end
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        def test_bigint_column_should_map_to_integer
+          bigint_column = PostgreSQLColumn.new('number', nil, "bigint")
+          assert_equal :integer, bigint_column.type
+        end
+
+        def test_smallint_column_should_map_to_integer
+          smallint_column = PostgreSQLColumn.new('number', nil, "smallint")
+          assert_equal :integer, smallint_column.type
+        end
+
+        def test_uuid_column_should_map_to_string
+          uuid_column = PostgreSQLColumn.new('unique_id', nil, "uuid")
+          assert_equal :string, uuid_column.type
+        end
+      end
     end
   end
 end
diff --git a/activerecord/test/cases/connection_pool_test.rb b/activerecord/test/cases/connection_pool_test.rb
index 2e18117895..7ac14fa8d6 100644
--- a/activerecord/test/cases/connection_pool_test.rb
+++ b/activerecord/test/cases/connection_pool_test.rb
@@ -3,6 +3,58 @@ require "cases/helper"
 module ActiveRecord
   module ConnectionAdapters
     class ConnectionPoolTest < ActiveRecord::TestCase
+      def setup
+        # 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
+
+      def test_pool_caches_columns
+        columns = @pool.columns['posts']
+        assert_equal columns, @pool.columns['posts']
+      end
+
+      def test_pool_caches_columns_hash
+        columns_hash = @pool.columns_hash['posts']
+        assert_equal columns_hash, @pool.columns_hash['posts']
+      end
+
+      def test_clearing_column_cache
+        @pool.columns['posts']
+        @pool.columns_hash['posts']
+
+        @pool.clear_cache!
+
+        assert_equal 0, @pool.columns.size
+        assert_equal 0, @pool.columns_hash.size
+      end
+
+      def test_primary_key
+        assert_equal 'id', @pool.primary_keys['posts']
+      end
+
+      def test_primary_key_for_non_existent_table
+        assert_equal 'id', @pool.primary_keys['omgponies']
+      end
+
+      def test_primary_key_is_set_on_columns
+        posts_columns = @pool.columns_hash['posts']
+        assert posts_columns['id'].primary
+
+        (posts_columns.keys - ['id']).each do |key|
+          assert !posts_columns[key].primary
+        end
+      end
+
       def test_clear_stale_cached_connections!
         pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec
 
@@ -55,6 +107,26 @@ module ActiveRecord
         end.join()
 
       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
     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..d63ecdbcc5
--- /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.find(1, :lock => 'LOCK IN SHARE MODE')
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
index f4af6506c5..2e620d8b03 100644
--- a/activerecord/test/cases/finder_test.rb
+++ b/activerecord/test/cases/finder_test.rb
@@ -984,7 +984,7 @@ class FinderTest < ActiveRecord::TestCase
 
   def test_select_rows
     assert_equal(
-      [["1", nil, nil, "37signals"],
+      [["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?}})
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index 9ce163a00f..fa40fad56d 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -13,6 +13,7 @@ require 'models/category'
 require 'models/parrot'
 require 'models/pirate'
 require 'models/treasure'
+require 'models/traffic_light'
 require 'models/matey'
 require 'models/ship'
 require 'models/book'
@@ -24,7 +25,7 @@ class FixturesTest < ActiveRecord::TestCase
   self.use_instantiated_fixtures = true
   self.use_transactional_fixtures = false
 
-  fixtures :topics, :developers, :accounts, :tasks, :categories, :funny_jokes, :binaries
+  fixtures :topics, :developers, :accounts, :tasks, :categories, :funny_jokes, :binaries, :traffic_lights
 
   FIXTURES = %w( accounts binaries companies customers
                  developers developers_projects entrants
@@ -34,7 +35,7 @@ class FixturesTest < ActiveRecord::TestCase
   def test_clean_fixtures
     FIXTURES.each do |name|
       fixtures = nil
-      assert_nothing_raised { fixtures = create_fixtures(name) }
+      assert_nothing_raised { fixtures = create_fixtures(name).first }
       assert_kind_of(Fixtures, fixtures)
       fixtures.each { |_name, fixture|
         fixture.each { |key, value|
@@ -52,7 +53,7 @@ class FixturesTest < ActiveRecord::TestCase
   end
 
   def test_attributes
-    topics = create_fixtures("topics")
+    topics = create_fixtures("topics").first
     assert_equal("The First Topic", topics["first"]["title"])
     assert_nil(topics["second"]["author_email_address"])
   end
@@ -126,12 +127,11 @@ class FixturesTest < ActiveRecord::TestCase
   end
 
   def test_instantiation
-    topics = create_fixtures("topics")
+    topics = create_fixtures("topics").first
     assert_kind_of Topic, topics["first"].find
   end
 
   def test_complete_instantiation
-    assert_equal 4, @topics.size
     assert_equal "The First Topic", @first.title
   end
 
@@ -141,7 +141,6 @@ class FixturesTest < ActiveRecord::TestCase
   end
 
   def test_erb_in_fixtures
-    assert_equal 11, @developers.size
     assert_equal "fixture_5", @dev_5.name
   end
 
@@ -198,12 +197,15 @@ class FixturesTest < ActiveRecord::TestCase
   end
 
   def test_binary_in_fixtures
-    assert_equal 1, @binaries.size
     data = File.open(ASSETS_ROOT + "/flowers.jpg", 'rb') { |f| f.read }
     data.force_encoding('ASCII-8BIT') if data.respond_to?(:force_encoding)
     data.freeze
     assert_equal data, @flowers.data
   end
+
+  def test_serialized_fixtures
+    assert_equal ["Green", "Red", "Orange"], traffic_lights(:uk).state
+  end
 end
 
 if Account.connection.respond_to?(:reset_pk_sequence!)
@@ -240,7 +242,7 @@ if Account.connection.respond_to?(:reset_pk_sequence!)
 
     def test_create_fixtures_resets_sequences_when_not_cached
       @instances.each do |instance|
-        max_id = create_fixtures(instance.class.table_name).inject(0) do |_max_id, (_, fixture)|
+        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
@@ -299,9 +301,6 @@ class FixturesWithoutInstanceInstantiationTest < ActiveRecord::TestCase
 
   def test_without_instance_instantiation
     assert !defined?(@first), "@first is not defined"
-    assert_not_nil @topics
-    assert_not_nil @developers
-    assert_not_nil @accounts
   end
 end
 
@@ -379,6 +378,21 @@ class ForeignKeyFixturesTest < ActiveRecord::TestCase
   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
@@ -504,7 +518,7 @@ class FasterFixturesTest < ActiveRecord::TestCase
   fixtures :categories, :authors
 
   def load_extra_fixture(name)
-    fixture = create_fixtures(name)
+    fixture = create_fixtures(name).first
     assert fixture.is_a?(Fixtures)
     @loaded_fixtures[fixture.table_name] = fixture
   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..15598392e2
--- /dev/null
+++ b/activerecord/test/cases/habtm_destroy_order_test.rb
@@ -0,0 +1,17 @@
+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
+  end
+end
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
index f9bbc5299b..fd20f1b120 100644
--- a/activerecord/test/cases/helper.rb
+++ b/activerecord/test/cases/helper.rb
@@ -11,7 +11,14 @@ require 'mocha'
 
 require 'active_record'
 require 'active_support/dependencies'
-require 'connection'
+begin
+  require 'connection'
+rescue LoadError
+  # If we cannot load connection we assume that driver was not loaded for this test case, so we load sqlite3 as default one.
+  # This allows for running separate test cases by simply running test file.
+  connection_type = defined?(JRUBY_VERSION) ? 'jdbc' : 'native'
+  require "test/connections/#{connection_type}_sqlite3/connection"
+end
 
 # Show backtraces for deprecated behavior for quicker cleanup.
 ActiveSupport::Deprecation.debug = true
@@ -19,6 +26,9 @@ ActiveSupport::Deprecation.debug = true
 # Quote "type" if it's a reserved word for the current connection.
 QUOTED_TYPE = ActiveRecord::Base.connection.quote_column_name('type')
 
+# Enable Identity Map for testing
+ActiveRecord::IdentityMap.enabled = (ENV['IM'] == "false" ? false : true)
+
 def current_adapter?(*types)
   types.any? do |type|
     ActiveRecord::ConnectionAdapters.const_defined?(type) &&
@@ -26,6 +36,15 @@ def current_adapter?(*types)
   end
 end
 
+def in_memory_db?
+  current_adapter?(:SQLiteAdapter) &&
+  ActiveRecord::Base.connection_pool.spec.config[:database] == ":memory:"
+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
@@ -40,42 +59,31 @@ ensure
   ActiveRecord::Base.default_timezone = old_zone
 end
 
-ActiveRecord::Base.connection.class.class_eval do
-  IGNORED_SQL = [/^PRAGMA/, /^SELECT currval/, /^SELECT CAST/, /^SELECT @@IDENTITY/, /^SELECT @@ROWCOUNT/, /^SAVEPOINT/, /^ROLLBACK TO SAVEPOINT/, /^RELEASE SAVEPOINT/, /SHOW FIELDS/]
+module ActiveRecord
+  class SQLCounter
+    IGNORED_SQL = [/^PRAGMA (?!(table_info))/, /^SELECT currval/, /^SELECT CAST/, /^SELECT @@IDENTITY/, /^SELECT @@ROWCOUNT/, /^SAVEPOINT/, /^ROLLBACK TO SAVEPOINT/, /^RELEASE SAVEPOINT/, /^SHOW max_identifier_length/]
 
-  # FIXME: this needs to be refactored so specific database can add their own
-  # ignored SQL.  This ignored SQL is for Oracle.
-  IGNORED_SQL.concat [/^select .*nextval/i, /^SAVEPOINT/, /^ROLLBACK TO/, /^\s*select .* from ((all|user)_tab_columns|(all|user)_triggers|(all|user)_constraints)/im]
+    # FIXME: this needs to be refactored so specific database can add their own
+    # ignored SQL.  This ignored SQL is for Oracle.
+    IGNORED_SQL.concat [/^select .*nextval/i, /^SAVEPOINT/, /^ROLLBACK TO/, /^\s*select .* from all_triggers/im]
 
-  def execute_with_query_record(sql, name = nil, &block)
-    $queries_executed ||= []
-    $queries_executed << sql unless IGNORED_SQL.any? { |r| sql =~ r }
-    execute_without_query_record(sql, name, &block)
-  end
+    def initialize
+      $queries_executed = []
+    end
 
-  alias_method_chain :execute, :query_record
+    def call(name, start, finish, message_id, values)
+      sql = values[:sql]
 
-  def exec_query_with_query_record(sql, name = nil, binds = [], &block)
-    $queries_executed ||= []
-    $queries_executed << sql unless IGNORED_SQL.any? { |r| sql =~ r }
-    exec_query_without_query_record(sql, name, binds, &block)
+      # FIXME: this seems bad. we should probably have a better way to indicate
+      # the query was cached
+      unless 'CACHE' == values[:name]
+        $queries_executed << sql unless IGNORED_SQL.any? { |r| sql =~ r }
+      end
+    end
   end
-
-  alias_method_chain :exec_query, :query_record
+  ActiveSupport::Notifications.subscribe('sql.active_record', SQLCounter.new)
 end
 
-ActiveRecord::Base.connection.class.class_eval {
-  attr_accessor :column_calls
-
-  def columns_with_calls(*args)
-    @column_calls ||= 0
-    @column_calls += 1
-    columns_without_calls(*args)
-  end
-
-  alias_method_chain :columns, :calls
-}
-
 unless ENV['FIXTURE_DEBUG']
   module ActiveRecord::TestFixtures::ClassMethods
     def try_to_load_dependency_with_silence(*args)
@@ -96,15 +104,15 @@ class ActiveSupport::TestCase
   self.use_transactional_fixtures = true
 
   def create_fixtures(*table_names, &block)
-    Fixtures.create_fixtures(ActiveSupport::TestCase.fixture_path, table_names, {}, &block)
+    Fixtures.create_fixtures(ActiveSupport::TestCase.fixture_path, table_names, fixture_class_names, &block)
   end
 end
 
-# silence verbose schema loading
-original_stdout = $stdout
-$stdout = StringIO.new
+def load_schema
+  # silence verbose schema loading
+  original_stdout = $stdout
+  $stdout = StringIO.new
 
-begin
   adapter_name = ActiveRecord::Base.connection.adapter_name.downcase
   adapter_specific_schema_file = SCHEMA_ROOT + "/#{adapter_name}_specific_schema.rb"
 
@@ -117,6 +125,8 @@ ensure
   $stdout = original_stdout
 end
 
+load_schema
+
 class << Time
   unless method_defined? :now_before_time_travel
     alias_method :now_before_time_travel, :now
@@ -133,4 +143,3 @@ class << Time
     @now = nil
   end
 end
-
diff --git a/activerecord/test/cases/identity_map_test.rb b/activerecord/test/cases/identity_map_test.rb
new file mode 100644
index 0000000000..d98638ab73
--- /dev/null
+++ b/activerecord/test/cases/identity_map_test.rb
@@ -0,0 +1,402 @@
+require "cases/helper"
+require 'models/developer'
+require 'models/project'
+require 'models/company'
+require 'models/topic'
+require 'models/reply'
+require 'models/computer'
+require 'models/customer'
+require 'models/order'
+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/subscriber'
+require "models/pirate"
+require "models/bird"
+require "models/parrot"
+
+if ActiveRecord::IdentityMap.enabled?
+class IdentityMapTest < ActiveRecord::TestCase
+  fixtures :accounts, :companies, :developers, :projects, :topics,
+    :developers_projects, :computers, :authors, :author_addresses,
+    :posts, :tags, :taggings, :comments, :subscribers
+
+  ##############################################################################
+  # Basic tests checking if IM is functioning properly on basic find operations#
+  ##############################################################################
+
+  def test_find_id
+    assert_same(Client.find(3), Client.find(3))
+  end
+
+  def test_find_id_without_identity_map
+    ActiveRecord::IdentityMap.without do
+      assert_not_same(Client.find(3), Client.find(3))
+    end
+  end
+
+  def test_find_id_use_identity_map
+    ActiveRecord::IdentityMap.enabled = false
+    ActiveRecord::IdentityMap.use do
+      assert_same(Client.find(3), Client.find(3))
+    end
+    ActiveRecord::IdentityMap.enabled = true
+  end
+
+  def test_find_pkey
+    assert_same(
+      Subscriber.find('swistak'),
+      Subscriber.find('swistak')
+    )
+  end
+
+  def test_find_by_id
+    assert_same(
+      Client.find_by_id(3),
+      Client.find_by_id(3)
+    )
+  end
+
+  def test_find_by_string_and_numeric_id
+    assert_same(
+      Client.find_by_id("3"),
+      Client.find_by_id(3)
+    )
+  end
+
+  def test_find_by_pkey
+    assert_same(
+      Subscriber.find_by_nick('swistak'),
+      Subscriber.find_by_nick('swistak')
+    )
+  end
+
+  def test_find_first_id
+    assert_same(
+      Client.find(:first, :conditions => {:id => 1}),
+      Client.find(:first, :conditions => {:id => 1})
+    )
+  end
+
+  def test_find_first_pkey
+    assert_same(
+      Subscriber.find(:first, :conditions => {:nick => 'swistak'}),
+      Subscriber.find(:first, :conditions => {:nick => 'swistak'})
+    )
+  end
+
+  ##############################################################################
+  # Tests checking if IM is functioning properly on more advanced finds        #
+  # and associations                                                           #
+  ##############################################################################
+
+  def test_owner_object_is_associated_from_identity_map
+    post = Post.find(1)
+    comment = post.comments.first
+
+    assert_no_queries do
+      comment.post
+    end
+    assert_same post, comment.post
+  end
+
+  def test_associated_object_are_assigned_from_identity_map
+    post = Post.find(1)
+
+    post.comments.each do |comment|
+      assert_same post, comment.post
+      assert_equal post.object_id, comment.post.object_id
+    end
+  end
+
+  def test_creation
+    t1 = Topic.create("title" => "t1")
+    t2 = Topic.find(t1.id)
+    assert_same(t1, t2)
+  end
+
+  ##############################################################################
+  # Tests checking dirty attribute behaviour with IM                           #
+  ##############################################################################
+
+  def test_loading_new_instance_should_not_update_dirty_attributes
+    swistak = Subscriber.find(:first, :conditions => {:nick => 'swistak'})
+    swistak.name = "Swistak Sreberkowiec"
+    assert_equal(["name"], swistak.changed)
+    assert_equal({"name" => ["Marcin Raczkowski", "Swistak Sreberkowiec"]}, swistak.changes)
+
+    s = Subscriber.find('swistak')
+
+    assert swistak.name_changed?
+    assert_equal("Swistak Sreberkowiec", swistak.name)
+  end
+
+  def test_loading_new_instance_should_change_dirty_attribute_original_value
+    swistak = Subscriber.find(:first, :conditions => {:nick => 'swistak'})
+    swistak.name = "Swistak Sreberkowiec"
+
+    Subscriber.update_all({:name => "Raczkowski Marcin"}, {:name => "Marcin Raczkowski"})
+
+    s = Subscriber.find('swistak')
+
+    assert_equal({'name' => ["Raczkowski Marcin", "Swistak Sreberkowiec"]}, swistak.changes)
+    assert_equal("Swistak Sreberkowiec", swistak.name)
+  end
+
+  def test_loading_new_instance_should_remove_dirt
+    swistak = Subscriber.find(:first, :conditions => {:nick => 'swistak'})
+    swistak.name = "Swistak Sreberkowiec"
+
+    assert_equal({"name" => ["Marcin Raczkowski", "Swistak Sreberkowiec"]}, swistak.changes)
+
+    Subscriber.update_all({:name => "Swistak Sreberkowiec"}, {:name => "Marcin Raczkowski"})
+
+    s = Subscriber.find('swistak')
+
+    assert_equal("Swistak Sreberkowiec", swistak.name)
+    assert_equal({}, swistak.changes)
+    assert !swistak.name_changed?
+  end
+
+  def test_has_many_associations
+    pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+    pirate.birds.create!(:name => 'Posideons Killer')
+    pirate.birds.create!(:name => 'Killer bandita Dionne')
+
+    posideons, killer = pirate.birds
+
+    pirate.reload
+
+    pirate.birds_attributes = [{ :id => posideons.id, :name => 'Grace OMalley' }]
+    assert_equal 'Grace OMalley', pirate.birds.to_a.find { |r| r.id == posideons.id }.name
+  end
+
+  def test_changing_associations
+    post1 = Post.create("title" => "One post", "body" => "Posting...")
+    post2 = Post.create("title" => "Another post", "body" => "Posting... Again...")
+    comment = Comment.new("body" => "comment")
+
+    comment.post = post1
+    assert comment.save
+
+    assert_same(post1.comments.first, comment)
+
+    comment.post = post2
+    assert comment.save
+
+    assert_same(post2.comments.first, comment)
+    assert_equal(0, post1.comments.size)
+  end
+
+  def test_im_with_polymorphic_has_many_going_through_join_model_with_custom_select_and_joins
+    tag = posts(:welcome).tags.first
+    tag_with_joins_and_select = posts(:welcome).tags.add_joins_and_select.first
+    assert_same(tag, tag_with_joins_and_select)
+    assert_nothing_raised(NoMethodError, "Joins/select was not loaded") { tag.author_id }
+  end
+
+  ##############################################################################
+  # Tests checking Identity Map behaviour with preloaded associations, joins,  #
+  # includes etc.                                                              #
+  ##############################################################################
+
+  def test_find_with_preloaded_associations
+    assert_queries(2) do
+      posts = Post.preload(:comments)
+      assert posts.first.comments.first
+    end
+
+    # With IM we'll retrieve post object from previous query, it'll have comments
+    # already preloaded from first call
+    assert_queries(1) do
+      posts = Post.preload(:comments).to_a
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.preload(:author)
+      assert posts.first.author
+    end
+
+    # With IM we'll retrieve post object from previous query, it'll have comments
+    # already preloaded from first call
+    assert_queries(1) do
+      posts = Post.preload(:author).to_a
+      assert posts.first.author
+    end
+
+    assert_queries(1) do
+      posts = Post.preload(:author, :comments).to_a
+      assert posts.first.author
+      assert posts.first.comments.first
+    end
+  end
+
+  def test_find_with_included_associations
+    assert_queries(2) do
+      posts = Post.includes(:comments)
+      assert posts.first.comments.first
+    end
+
+    assert_queries(1) do
+      posts = Post.scoped.includes(:comments)
+      assert posts.first.comments.first
+    end
+
+    assert_queries(2) do
+      posts = Post.includes(:author)
+      assert posts.first.author
+    end
+
+    assert_queries(1) do
+      posts = Post.includes(:author, :comments).to_a
+      assert posts.first.author
+      assert posts.first.comments.first
+    end
+  end
+
+  def test_eager_loading_with_conditions_on_joined_table_preloads
+    posts = Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => [:comments], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author}
+    assert_same posts.first.author, Author.first
+
+    posts = Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => [:comments], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author}
+    assert_same posts.first.author, Author.first
+
+    posts = Post.find(:all, :include => :author, :joins => {:taggings => :tag}, :conditions => "tags.name = 'General'", :order => 'posts.id')
+    assert_equal posts(:welcome, :thinking), posts
+    assert_same posts.first.author, Author.first
+
+    posts = Post.find(:all, :include => :author, :joins => {:taggings => {:tag => :taggings}}, :conditions => "taggings_tags.super_tag_id=2", :order => 'posts.id')
+    assert_equal posts(:welcome, :thinking), posts
+    assert_same posts.first.author, Author.first
+  end
+
+  def test_eager_loading_with_conditions_on_string_joined_table_preloads
+    posts = assert_queries(2) do
+      Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => "INNER JOIN comments on comments.post_id = posts.id", :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author}
+
+    posts = assert_queries(1) do
+      Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => ["INNER JOIN comments on comments.post_id = posts.id"], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
+    end
+    assert_equal [posts(:welcome)], posts
+    assert_equal authors(:david), assert_no_queries { posts[0].author}
+  end
+
+  ##############################################################################
+  # Behaviour releated to saving failures
+  ##############################################################################
+
+  def test_reload_object_if_save_failed
+    developer = Developer.first
+    developer.salary = 0
+
+    assert !developer.save
+
+    same_developer = Developer.first
+
+    assert_not_same  developer, same_developer
+    assert_not_equal 0, same_developer.salary
+    assert_not_equal developer.salary, same_developer.salary
+  end
+
+  def test_reload_object_if_forced_save_failed
+    developer = Developer.first
+    developer.salary = 0
+
+    assert_raise(ActiveRecord::RecordInvalid) { developer.save! }
+
+    same_developer = Developer.first
+
+    assert_not_same  developer, same_developer
+    assert_not_equal 0, same_developer.salary
+    assert_not_equal developer.salary, same_developer.salary
+  end
+
+  def test_reload_object_if_update_attributes_fails
+    developer = Developer.first
+    developer.salary = 0
+
+    assert !developer.update_attributes(:salary => 0)
+
+    same_developer = Developer.first
+
+    assert_not_same  developer, same_developer
+    assert_not_equal 0, same_developer.salary
+    assert_not_equal developer.salary, same_developer.salary
+  end
+
+  ##############################################################################
+  # Behaviour of readonly, forzen, destroyed
+  ##############################################################################
+
+  def test_find_using_identity_map_respects_readonly_when_loading_associated_object_first
+    author  = Author.first
+    readonly_comment = author.readonly_comments.first
+
+    comment = Comment.first
+    assert !comment.readonly?
+
+    assert readonly_comment.readonly?
+
+    assert_raise(ActiveRecord::ReadOnlyRecord) {readonly_comment.save}
+    assert comment.save
+  end
+
+  def test_find_using_identity_map_respects_readonly
+    comment = Comment.first
+    assert !comment.readonly?
+
+    author  = Author.first
+    readonly_comment = author.readonly_comments.first
+
+    assert readonly_comment.readonly?
+
+    assert_raise(ActiveRecord::ReadOnlyRecord) {readonly_comment.save}
+    assert comment.save
+  end
+
+  def test_find_using_select_and_identity_map
+    author_id, author = Author.select('id').first, Author.first
+
+    assert_equal author_id, author
+    assert_same author_id, author
+    assert_not_nil author.name
+
+    post, post_id = Post.first, Post.select('id').first
+
+    assert_equal post_id, post
+    assert_same post_id, post
+    assert_not_nil post.title
+  end
+
+# Currently AR is not allowing changing primary key (see Persistence#update)
+# So we ignore it. If this changes, this test needs to be uncommented.
+#  def test_updating_of_pkey
+#    assert client = Client.find(3),
+#    client.update_attribute(:id, 666)
+#
+#    assert Client.find(666)
+#    assert_same(client, Client.find(666))
+#
+#    s = Subscriber.find_by_nick('swistak')
+#    assert s.update_attribute(:nick, 'swistakTheJester')
+#    assert_equal('swistakTheJester', s.nick)
+#
+#    assert stj = Subscriber.find_by_nick('swistakTheJester')
+#    assert_same(s, stj)
+#  end
+
+end
+end
diff --git a/activerecord/test/cases/inheritance_test.rb b/activerecord/test/cases/inheritance_test.rb
index c3da9cdf53..b5d8314541 100644
--- a/activerecord/test/cases/inheritance_test.rb
+++ b/activerecord/test/cases/inheritance_test.rb
@@ -203,12 +203,12 @@ class InheritanceTest < ActiveRecord::TestCase
 
   def test_eager_load_belongs_to_something_inherited
     account = Account.find(1, :include => :firm)
-    assert_not_nil account.instance_variable_get("@firm"), "nil proves eager load failed"
+    assert account.association_cache.key?(:firm), "nil proves eager load failed"
   end
 
   def test_eager_load_belongs_to_primary_key_quoting
     con = Account.connection
-    assert_sql(/\(#{con.quote_table_name('companies')}.#{con.quote_column_name('id')} = 1\)/) do
+    assert_sql(/#{con.quote_table_name('companies')}.#{con.quote_column_name('id')} IN \(1\)/) do
       Account.find(1, :include => :firm)
     end
   end
@@ -219,6 +219,10 @@ class InheritanceTest < ActiveRecord::TestCase
     switch_to_default_inheritance_column
   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 }
diff --git a/activerecord/test/cases/lifecycle_test.rb b/activerecord/test/cases/lifecycle_test.rb
index b8c3ffb9cb..6cd8494c9e 100644
--- a/activerecord/test/cases/lifecycle_test.rb
+++ b/activerecord/test/cases/lifecycle_test.rb
@@ -7,6 +7,16 @@ require 'models/comment'
 
 class SpecialDeveloper < Developer; end
 
+class DeveloperObserver < ActiveRecord::Observer
+  def calls
+    @calls ||= []
+  end
+
+  def before_save(developer)
+    calls << developer
+  end
+end
+
 class SalaryChecker < ActiveRecord::Observer
   observe :special_developer
   attr_accessor :last_saved
@@ -101,9 +111,10 @@ class LifecycleTest < ActiveRecord::TestCase
   fixtures :topics, :developers, :minimalistics
 
   def test_before_destroy
-    original_count = Topic.count
-    (topic_to_be_destroyed = Topic.find(1)).destroy
-    assert_equal original_count - (1 + topic_to_be_destroyed.replies.size), Topic.count
+    topic = Topic.find(1)
+    assert_difference 'Topic.count', -(1 + topic.replies.size) do
+      topic.destroy
+    end
   end
 
   def test_auto_observer
@@ -195,4 +206,14 @@ class LifecycleTest < ActiveRecord::TestCase
     assert_equal developer, SalaryChecker.instance.last_saved
   end
 
+  def test_observer_is_called_once
+    observer = DeveloperObserver.instance # activate
+    observer.calls.clear
+
+    developer = Developer.create! :name => 'Ancestor', :salary => 100000
+    special_developer = SpecialDeveloper.create! :name => 'Descendent', :salary => 100000
+
+    assert_equal [developer, special_developer], observer.calls
+  end
+
 end
diff --git a/activerecord/test/cases/locking_test.rb b/activerecord/test/cases/locking_test.rb
index f9678cb0c5..636a709924 100644
--- a/activerecord/test/cases/locking_test.rb
+++ b/activerecord/test/cases/locking_test.rb
@@ -1,6 +1,7 @@
 require 'thread'
 require "cases/helper"
 require 'models/person'
+require 'models/job'
 require 'models/reader'
 require 'models/legacy_thing'
 require 'models/reference'
@@ -19,11 +20,6 @@ end
 class OptimisticLockingTest < 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
-
   def test_lock_existing
     p1 = Person.find(1)
     p2 = Person.find(1)
@@ -103,6 +99,14 @@ class OptimisticLockingTest < ActiveRecord::TestCase
     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)
@@ -152,6 +156,33 @@ class OptimisticLockingTest < ActiveRecord::TestCase
     assert_equal "unchangeable name", p.first_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
+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|
@@ -198,24 +229,6 @@ class OptimisticLockingTest < ActiveRecord::TestCase
     assert_raises(ActiveRecord::RecordNotFound) { LegacyThing.find(t.id) }
   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
-
   private
 
     def add_counter_column_to(model, col='test_count')
@@ -252,7 +265,7 @@ end
 
 # TODO: The Sybase, and OpenBase adapters currently have no support for pessimistic locking
 
-unless current_adapter?(:SybaseAdapter, :OpenBaseAdapter)
+unless current_adapter?(:SybaseAdapter, :OpenBaseAdapter) || in_memory_db?
   class PessimisticLockingTest < ActiveRecord::TestCase
     self.use_transactional_fixtures = false
     fixtures :people, :readers
diff --git a/activerecord/test/cases/method_scoping_test.rb b/activerecord/test/cases/method_scoping_test.rb
index 0ffd0e2ab3..7e8383da9e 100644
--- a/activerecord/test/cases/method_scoping_test.rb
+++ b/activerecord/test/cases/method_scoping_test.rb
@@ -14,7 +14,7 @@ class MethodScopingTest < ActiveRecord::TestCase
 
   def test_set_conditions
     Developer.send(:with_scope, :find => { :conditions => 'just a test...' }) do
-      assert_equal '(just a test...)', Developer.scoped.arel.send(:where_clauses).join(' AND ')
+      assert_match '(just a test...)', Developer.scoped.arel.to_sql
     end
   end
 
@@ -227,7 +227,7 @@ class MethodScopingTest < ActiveRecord::TestCase
   end
 
   def test_scoped_create_with_join_and_merge
-    (Comment.where(:body => "but Who's Buying?").joins(:post) & Post.where(:body => 'Peace Sells...')).with_scope do
+    Comment.where(:body => "but Who's Buying?").joins(:post).merge(Post.where(:body => 'Peace Sells...')).with_scope do
       assert_equal({:body => "but Who's Buying?"}, Comment.scoped.scope_for_create)
     end
   end
@@ -275,7 +275,7 @@ class NestedScopingTest < ActiveRecord::TestCase
     Developer.send(:with_scope, :find => { :conditions => 'salary = 80000' }) do
       Developer.send(:with_scope, :find => { :limit => 10 }) do
         devs = Developer.scoped
-        assert_equal '(salary = 80000)', devs.arel.send(:where_clauses).join(' AND ')
+        assert_match '(salary = 80000)', devs.arel.to_sql
         assert_equal 10, devs.taken
       end
     end
@@ -309,7 +309,7 @@ class NestedScopingTest < ActiveRecord::TestCase
     Developer.send(:with_scope, :find => { :conditions => "name = 'David'" }) do
       Developer.send(:with_scope, :find => { :conditions => 'salary = 80000' }) do
         devs = Developer.scoped
-        assert_equal "(name = 'David') AND (salary = 80000)", devs.arel.send(:where_clauses).join(' AND ')
+        assert_match "(name = 'David') AND (salary = 80000)", devs.arel.to_sql
         assert_equal(1, Developer.count)
       end
       Developer.send(:with_scope, :find => { :conditions => "name = 'Maiha'" }) do
@@ -322,7 +322,7 @@ class NestedScopingTest < ActiveRecord::TestCase
     Developer.send(:with_scope, :find => { :conditions => 'salary = 80000', :limit => 10 }) do
       Developer.send(:with_scope, :find => { :conditions => "name = 'David'" }) do
         devs = Developer.scoped
-        assert_equal "(salary = 80000) AND (name = 'David')", devs.arel.send(:where_clauses).join(' AND ')
+        assert_match "(salary = 80000) AND (name = 'David')", devs.arel.to_sql
         assert_equal 10, devs.taken
       end
     end
diff --git a/activerecord/test/cases/migration/command_recorder_test.rb b/activerecord/test/cases/migration/command_recorder_test.rb
index ea2292dda5..ae531ebb4c 100644
--- a/activerecord/test/cases/migration/command_recorder_test.rb
+++ b/activerecord/test/cases/migration/command_recorder_test.rb
@@ -16,7 +16,7 @@ module ActiveRecord
 
       def test_send_calls_super
         assert_raises(NoMethodError) do
-          @recorder.send(:create_table, :horses)
+          @recorder.send(:non_existing_method, :horses)
         end
       end
 
diff --git a/activerecord/test/cases/migration_test.rb b/activerecord/test/cases/migration_test.rb
index 1a65045ded..9d7c49768b 100644
--- a/activerecord/test/cases/migration_test.rb
+++ b/activerecord/test/cases/migration_test.rb
@@ -14,7 +14,7 @@ if ActiveRecord::Base.connection.supports_migrations?
   class Reminder < ActiveRecord::Base; end
 
   class ActiveRecord::Migration
-    class <<self
+    class << self
       attr_accessor :message_count
     end
 
@@ -1923,6 +1923,149 @@ if ActiveRecord::Base.connection.supports_migrations?
     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| }
+      end
+
+      def teardown
+        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 everytime 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) 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
@@ -2083,4 +2226,3 @@ if ActiveRecord::Base.connection.supports_migrations?
     end
   end
 end
-
diff --git a/activerecord/test/cases/modules_test.rb b/activerecord/test/cases/modules_test.rb
index 14870cb0e2..a2041af16a 100644
--- a/activerecord/test/cases/modules_test.rb
+++ b/activerecord/test/cases/modules_test.rb
@@ -49,7 +49,6 @@ class ModulesTest < ActiveRecord::TestCase
 
   def test_find_account_and_include_company
     account = MyApplication::Billing::Account.find(1, :include => :firm)
-    assert_kind_of MyApplication::Business::Firm, account.instance_variable_get('@firm')
     assert_kind_of MyApplication::Business::Firm, account.firm
   end
 
diff --git a/activerecord/test/cases/named_scope_test.rb b/activerecord/test/cases/named_scope_test.rb
index 6ac3e3fc56..fb050c3e52 100644
--- a/activerecord/test/cases/named_scope_test.rb
+++ b/activerecord/test/cases/named_scope_test.rb
@@ -64,6 +64,10 @@ class NamedScopeTest < ActiveRecord::TestCase
     assert Reply.scopes.include?(:base)
     assert_equal Reply.find(:all), Reply.base
   end
+  
+  def test_classes_dont_inherit_subclasses_scopes
+    assert !ActiveRecord::Base.scopes.include?(:base)
+  end
 
   def test_scopes_with_options_limit_finds_to_those_matching_the_criteria_specified
     assert !Topic.find(:all, :conditions => {:approved => true}).empty?
@@ -141,26 +145,26 @@ class NamedScopeTest < ActiveRecord::TestCase
     assert_equal 1, Topic.multiple_extensions.extension_one
   end
 
-  def test_has_many_associations_have_access_to_named_scopes
+  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_named_scope_with_STI
+  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_named_scopes
+  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_named_scopes_honor_current_scopes_from_when_defined
+  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)
@@ -236,7 +240,7 @@ class NamedScopeTest < ActiveRecord::TestCase
     end
   end
 
-  def test_any_should_not_fire_query_if_named_scope_loaded
+  def test_any_should_not_fire_query_if_scope_loaded
     topics = Topic.base
     topics.collect # force load
     assert_no_queries { assert topics.any? }
@@ -259,7 +263,7 @@ class NamedScopeTest < ActiveRecord::TestCase
     end
   end
 
-  def test_many_should_not_fire_query_if_named_scope_loaded
+  def test_many_should_not_fire_query_if_scope_loaded
     topics = Topic.base
     topics.collect # force load
     assert_no_queries { assert topics.many? }
@@ -276,27 +280,27 @@ class NamedScopeTest < ActiveRecord::TestCase
     assert Topic.base.many?
   end
 
-  def test_should_build_on_top_of_named_scope
+  def test_should_build_on_top_of_scope
     topic = Topic.approved.build({})
     assert topic.approved
   end
 
-  def test_should_build_new_on_top_of_named_scope
+  def test_should_build_new_on_top_of_scope
     topic = Topic.approved.new
     assert topic.approved
   end
 
-  def test_should_create_on_top_of_named_scope
+  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_named_scope
+  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_named_scopes
+  def test_should_build_on_top_of_chained_scopes
     topic = Topic.approved.by_lifo.build({})
     assert topic.approved
     assert_equal 'lifo', topic.author_name
@@ -310,7 +314,7 @@ class NamedScopeTest < ActiveRecord::TestCase
     assert_kind_of Topic, Topic.approved.sample
   end
 
-  def test_should_use_where_in_query_for_named_scope
+  def test_should_use_where_in_query_for_scope
     assert_equal Developer.find_all_by_name('Jamis').to_set, Developer.find_all_by_id(Developer.jamises).to_set
   end
 
@@ -361,7 +365,7 @@ class NamedScopeTest < ActiveRecord::TestCase
     assert_equal [posts(:sti_comments)], Post.with_special_comments.with_post(4).all.uniq
   end
 
-  def test_named_scopes_batch_finders
+  def test_scopes_batch_finders
     assert_equal 3, Topic.approved.count
 
     assert_queries(4) do
@@ -381,7 +385,7 @@ class NamedScopeTest < ActiveRecord::TestCase
     end
   end
 
-  def test_named_scopes_with_reserved_names
+  def test_scopes_with_reserved_names
     class << Topic
       def public_method; end
       public :public_method
@@ -400,7 +404,7 @@ class NamedScopeTest < ActiveRecord::TestCase
     end
   end
 
-  def test_named_scopes_on_relations
+  def test_scopes_on_relations
     # Topic.replied
     approved_topics = Topic.scoped.approved.order('id DESC')
     assert_equal topics(:fourth), approved_topics.first
@@ -409,19 +413,19 @@ class NamedScopeTest < ActiveRecord::TestCase
     assert_equal topics(:third), replied_approved_topics.first
   end
 
-  def test_index_on_named_scope
+  def test_index_on_scope
     approved = Topic.approved.order('id ASC')
     assert_equal topics(:second), approved[0]
     assert approved.loaded?
   end
 
-  def test_nested_named_scopes_queries_size
+  def test_nested_scopes_queries_size
     assert_queries(1) do
       Topic.approved.by_lifo.replied.written_before(Time.now).all
     end
   end
 
-  def test_named_scopes_are_cached_on_associations
+  def test_scopes_are_cached_on_associations
     post = posts(:welcome)
 
     assert_equal post.comments.containing_the_letter_e.object_id, post.comments.containing_the_letter_e.object_id
@@ -430,7 +434,7 @@ class NamedScopeTest < ActiveRecord::TestCase
     assert_no_queries { post.comments.containing_the_letter_e.all }
   end
 
-  def test_named_scopes_with_arguments_are_cached_on_associations
+  def test_scopes_with_arguments_are_cached_on_associations
     post = posts(:welcome)
 
     one = post.comments.limit_by(1).all
@@ -443,17 +447,17 @@ class NamedScopeTest < ActiveRecord::TestCase
     assert_no_queries { post.comments.limit_by(2).all }
   end
 
-  def test_named_scopes_are_reset_on_association_reload
+  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.comments.send(method)
+      post.association(:comments).send(method)
       assert before.object_id != post.comments.containing_the_letter_e.object_id, "AssociationCollection##{method} should reset the named scopes cache"
     end
   end
 
-  def test_named_scoped_are_lazy_loaded_if_table_still_does_not_exist
+  def test_scoped_are_lazy_loaded_if_table_still_does_not_exist
     assert_nothing_raised do
       require "models/without_table"
     end
diff --git a/activerecord/test/cases/nested_attributes_test.rb b/activerecord/test/cases/nested_attributes_test.rb
index ffcc7a081a..c57ab7ed28 100644
--- a/activerecord/test/cases/nested_attributes_test.rb
+++ b/activerecord/test/cases/nested_attributes_test.rb
@@ -147,6 +147,15 @@ class TestNestedAttributesInGeneral < ActiveRecord::TestCase
     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 => 'gardning'
+    man = Man.find man.id
+    man.interests_attributes = [{:id => interest.id, :topic => 'gardening'}]
+    assert_equal man.interests.first.topic, man.interests[0].topic
+  end
 end
 
 class TestNestedAttributesOnAHasOneAssociation < ActiveRecord::TestCase
@@ -298,7 +307,7 @@ class TestNestedAttributesOnAHasOneAssociation < ActiveRecord::TestCase
 
   def test_should_create_new_model_when_nothing_is_there_and_update_only_is_true
     @ship.delete
-    
+
     @pirate.reload.update_attributes(:update_only_ship_attributes => { :name => 'Mayflower' })
 
     assert_not_nil @pirate.ship
@@ -451,7 +460,7 @@ class TestNestedAttributesOnABelongsToAssociation < ActiveRecord::TestCase
 
   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
@@ -859,7 +868,7 @@ class TestNestedAttributesWithNonStandardPrimaryKeys < ActiveRecord::TestCase
 end
 
 class TestHasOneAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @pirate = Pirate.create!(:catchphrase => "My baby takes tha mornin' train!")
@@ -899,7 +908,7 @@ class TestHasOneAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveRe
 end
 
 class TestHasManyAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @ship = Ship.create!(:name => "The good ship Dollypop")
@@ -909,16 +918,16 @@ class TestHasManyAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveR
 
   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.parts.proxy_target.size
+    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.parts.proxy_target.size
+    assert_equal 1, @ship.association(:parts).target.size
     assert_equal 'Mast', @ship.parts[0].name
-    assert_no_difference("@ship.parts[0].trinkets.proxy_target.size") do
-      @ship.parts[0].trinkets.proxy_target.size
+    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
diff --git a/activerecord/test/cases/pooled_connections_test.rb b/activerecord/test/cases/pooled_connections_test.rb
index de5fa140ba..6269437b14 100644
--- a/activerecord/test/cases/pooled_connections_test.rb
+++ b/activerecord/test/cases/pooled_connections_test.rb
@@ -137,4 +137,4 @@ class PooledConnectionsTest < ActiveRecord::TestCase
   def add_record(name)
     ActiveRecord::Base.connection_pool.with_connection { Project.create! :name => name }
   end
-end unless %w(FrontBase).include? ActiveRecord::Base.connection.adapter_name
+end unless current_adapter?(:FrontBase) || in_memory_db?
diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
index 33916c4e46..53aefc7b58 100644
--- a/activerecord/test/cases/query_cache_test.rb
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -63,7 +63,7 @@ class QueryCacheTest < ActiveRecord::TestCase
       # 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) && SQLite3::Version::VERSION > '1.2.5' || current_adapter?(:Mysql2Adapter) || current_adapter?(:MysqlAdapter)
+      elsif current_adapter?(:SQLite3Adapter) && SQLite3::VERSION > '1.2.5' || current_adapter?(:Mysql2Adapter) || current_adapter?(:MysqlAdapter)
         # Future versions of the sqlite3 adapter will return numeric
         assert_instance_of Fixnum,
          Task.connection.select_value("SELECT count(*) AS count_all FROM tasks")
diff --git a/activerecord/test/cases/quoting_test.rb b/activerecord/test/cases/quoting_test.rb
index 2ef5b5a800..b87fb51d97 100644
--- a/activerecord/test/cases/quoting_test.rb
+++ b/activerecord/test/cases/quoting_test.rb
@@ -154,13 +154,13 @@ module ActiveRecord
       end
 
       def test_crazy_object
-        crazy = Class.new { def to_s; 'lol' end }.new
+        crazy = Class.new { def to_yaml; 'lol' end }.new
         assert_equal "'lol'", @quoter.quote(crazy, nil)
         assert_equal "'lol'", @quoter.quote(crazy, Object.new)
       end
 
       def test_crazy_object_calls_quote_string
-        crazy = Class.new { def to_s; 'lo\l' end }.new
+        crazy = Class.new { def to_yaml; 'lo\l' end }.new
         assert_equal "'lo\\\\l'", @quoter.quote(crazy, nil)
         assert_equal "'lo\\\\l'", @quoter.quote(crazy, Object.new)
       end
diff --git a/activerecord/test/cases/readonly_test.rb b/activerecord/test/cases/readonly_test.rb
index 98011f40a4..e21109baae 100644
--- a/activerecord/test/cases/readonly_test.rb
+++ b/activerecord/test/cases/readonly_test.rb
@@ -6,13 +6,8 @@ require 'models/project'
 require 'models/reader'
 require 'models/person'
 
-# Dummy class methods to test implicit association scoping.
-def Comment.foo() find :first end
-def Project.foo() find :first end
-
-
 class ReadOnlyTest < ActiveRecord::TestCase
-  fixtures :posts, :comments, :developers, :projects, :developers_projects
+  fixtures :posts, :comments, :developers, :projects, :developers_projects, :people, :readers
 
   def test_cant_save_readonly_record
     dev = Developer.find(1)
@@ -49,15 +44,6 @@ class ReadOnlyTest < ActiveRecord::TestCase
     Developer.joins(', projects').readonly(false).each { |d| assert !d.readonly? }
   end
 
-
-  def test_habtm_find_readonly
-    dev = Developer.find(1)
-    assert !dev.projects.empty?
-    assert dev.projects.all?(&:readonly?)
-    assert dev.projects.find(:all).all?(&:readonly?)
-    assert dev.projects.readonly(true).all?(&:readonly?)
-  end
-
   def test_has_many_find_readonly
     post = Post.find(1)
     assert !post.comments.empty?
@@ -71,6 +57,18 @@ class ReadOnlyTest < ActiveRecord::TestCase
     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.send(:with_scope, :find => { :conditions => '1=1' }) do
       assert !Post.find(1).readonly?
@@ -102,7 +100,13 @@ class ReadOnlyTest < ActiveRecord::TestCase
   end
 
   def test_association_collection_method_missing_scoping_not_readonly
-    assert !Developer.find(1).projects.foo.readonly?
-    assert !Post.find(1).comments.foo.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/reflection_test.rb b/activerecord/test/cases/reflection_test.rb
index c461bb401f..9529ae56b8 100644
--- a/activerecord/test/cases/reflection_test.rb
+++ b/activerecord/test/cases/reflection_test.rb
@@ -17,6 +17,7 @@ require 'models/book'
 require 'models/subscriber'
 require 'models/subscription'
 require 'models/tag'
+require 'models/sponsor'
 
 class ReflectionTest < ActiveRecord::TestCase
   include ActiveRecord::Reflection
@@ -136,11 +137,11 @@ class ReflectionTest < ActiveRecord::TestCase
 
   def test_belongs_to_inferred_foreign_key_from_assoc_name
     Company.belongs_to :foo
-    assert_equal "foo_id", Company.reflect_on_association(:foo).primary_key_name
+    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).primary_key_name
+    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).primary_key_name
+    assert_equal "xyzzy_id", Company.reflect_on_association(:baz).foreign_key
   end
 
   def test_association_reflection_in_modules
@@ -187,8 +188,8 @@ class ReflectionTest < ActiveRecord::TestCase
 
   def test_reflection_of_all_associations
     # FIXME these assertions bust a lot
-    assert_equal 37, Firm.reflect_on_all_associations.size
-    assert_equal 27, Firm.reflect_on_all_associations(:has_many).size
+    assert_equal 36, Firm.reflect_on_all_associations.size
+    assert_equal 26, Firm.reflect_on_all_associations(:has_many).size
     assert_equal 10, Firm.reflect_on_all_associations(:has_one).size
     assert_equal 0, Firm.reflect_on_all_associations(:belongs_to).size
   end
@@ -243,6 +244,7 @@ class ReflectionTest < ActiveRecord::TestCase
     # 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 "id",   Tagging.reflect_on_association(:taggable).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
@@ -255,6 +257,11 @@ class ReflectionTest < ActiveRecord::TestCase
     assert_equal "name", Author.reflect_on_association(:essay).active_record_primary_key.to_s
   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?
@@ -292,6 +299,18 @@ class ReflectionTest < ActiveRecord::TestCase
     assert !AssociationReflection.new(:has_and_belongs_to_many, :clients, { :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_primary_key_name
+    assert_deprecated do
+      assert_equal "author_id", Author.reflect_on_association(:posts).primary_key_name.to_s
+      assert_equal "category_id", Post.reflect_on_association(:categorizations).primary_key_name.to_s
+    end
+  end
+
   private
     def assert_reflection(klass, association, options)
       assert reflection = klass.reflect_on_association(association)
diff --git a/activerecord/test/cases/relation_scoping_test.rb b/activerecord/test/cases/relation_scoping_test.rb
index 1f43515558..7369aaea1d 100644
--- a/activerecord/test/cases/relation_scoping_test.rb
+++ b/activerecord/test/cases/relation_scoping_test.rb
@@ -152,7 +152,7 @@ class NestedRelationScopingTest < ActiveRecord::TestCase
     Developer.where('salary = 80000').scoping do
       Developer.limit(10).scoping do
         devs = Developer.scoped
-        assert_equal '(salary = 80000)', devs.arel.send(:where_clauses).join(' AND ')
+        assert_match '(salary = 80000)', devs.arel.to_sql
         assert_equal 10, devs.taken
       end
     end
@@ -259,7 +259,8 @@ class HasManyScopingTest< ActiveRecord::TestCase
   end
 
   def test_should_default_scope_on_associations_is_overriden_by_association_conditions
-    assert_equal [], people(:michael).fixed_bad_references
+    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
@@ -422,7 +423,7 @@ class DefaultScopingTest < ActiveRecord::TestCase
     assert_equal expected, received
   end
 
-  def test_named_scope_overwrites_default
+  def test_scope_overwrites_default
     expected = Developer.find(:all, :order => 'salary DESC, name DESC').collect { |dev| dev.name }
     received = DeveloperOrderedBySalary.by_name.find(:all).collect { |dev| dev.name }
     assert_equal expected, received
@@ -485,4 +486,21 @@ class DefaultScopingTest < ActiveRecord::TestCase
     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
 end
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 688fc70484..54537f11a8 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -27,6 +27,12 @@ class RelationTest < ActiveRecord::TestCase
     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.scoped
     assert_equal [], relation.bind_values
@@ -36,7 +42,7 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal [], relation.bind_values
   end
 
-  def test_two_named_scopes_with_includes_should_not_drop_any_include
+  def test_two_scopes_with_includes_should_not_drop_any_include
     car = Car.incl_engines.incl_tyres.first
     assert_no_queries { car.tyres.length }
     assert_no_queries { car.engines.length }
@@ -184,6 +190,10 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal [2, 4, 6, 8, 10], even_ids.sort
   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
@@ -248,7 +258,7 @@ class RelationTest < ActiveRecord::TestCase
     end
   end
 
-  def test_respond_to_class_methods_and_named_scopes
+  def test_respond_to_class_methods_and_scopes
     assert DeveloperOrderedBySalary.scoped.respond_to?(:all_ordered_by_name)
     assert Topic.scoped.respond_to?(:by_lifo)
   end
@@ -275,8 +285,8 @@ class RelationTest < ActiveRecord::TestCase
       assert posts.first.comments.first
     end
 
-    assert_queries(2) do
-      posts = Post.preload(:comments).order('posts.id').to_a
+    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+      posts = Post.preload(:comments).to_a
       assert posts.first.comments.first
     end
 
@@ -285,13 +295,13 @@ class RelationTest < ActiveRecord::TestCase
       assert posts.first.author
     end
 
-    assert_queries(2) do
-      posts = Post.preload(:author).order('posts.id').to_a
+    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+      posts = Post.preload(:author).to_a
       assert posts.first.author
     end
 
-    assert_queries(3) do
-      posts = Post.preload(:author, :comments).order('posts.id').to_a
+    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 3) do
+      posts = Post.preload(:author, :comments).to_a
       assert posts.first.author
       assert posts.first.comments.first
     end
@@ -303,8 +313,8 @@ class RelationTest < ActiveRecord::TestCase
       assert posts.first.comments.first
     end
 
-    assert_queries(2) do
-      posts = Post.scoped.includes(:comments).order('posts.id')
+    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+      posts = Post.scoped.includes(:comments)
       assert posts.first.comments.first
     end
 
@@ -313,8 +323,8 @@ class RelationTest < ActiveRecord::TestCase
       assert posts.first.author
     end
 
-    assert_queries(3) do
-      posts = Post.includes(:author, :comments).order('posts.id').to_a
+    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 3) do
+      posts = Post.includes(:author, :comments).to_a
       assert posts.first.author
       assert posts.first.comments.first
     end
@@ -464,10 +474,17 @@ class RelationTest < ActiveRecord::TestCase
     relation = relation.where(:name => david.name)
     relation = relation.where(:name => 'Santiago')
     relation = relation.where(:id => david.id)
-    assert_equal [david], relation.all
+    assert_equal [], relation.all
+  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_ors
+  def test_find_all_with_multiple_should_use_and
     david = authors(:david)
     relation = [
       { :name => david.name },
@@ -476,7 +493,34 @@ class RelationTest < ActiveRecord::TestCase
     ].inject(Author.unscoped) do |memo, param|
       memo.where(param)
     end
-    assert_equal [david], relation.all
+    assert_equal [], relation.all
+  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.all
+    }
+  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.all
+    }
+  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.all
+    }
   end
 
   def test_exists
@@ -535,17 +579,17 @@ class RelationTest < ActiveRecord::TestCase
   end
 
   def test_relation_merging
-    devs = Developer.where("salary >= 80000") & Developer.limit(2) & Developer.order('id ASC').where("id < 3")
+    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) & Developer.order('id DESC') & Developer.select('developers.*')
+    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_merging_with_eager_load
     relations = []
-    relations << (Post.order('comments.id DESC') & Post.eager_load(:last_comment) & Post.scoped)
-    relations << (Post.eager_load(:last_comment) & Post.order('comments.id DESC') & Post.scoped)
+    relations << Post.order('comments.id DESC').merge(Post.eager_load(:last_comment)).merge(Post.scoped)
+    relations << Post.eager_load(:last_comment).merge(Post.order('comments.id DESC')).merge(Post.scoped)
 
     relations.each do |posts|
       post = posts.find { |p| p.id == 1 }
@@ -554,18 +598,20 @@ class RelationTest < ActiveRecord::TestCase
   end
 
   def test_relation_merging_with_locks
-    devs = Developer.lock.where("salary >= 80000").order("id DESC") & Developer.limit(2)
+    devs = Developer.lock.where("salary >= 80000").order("id DESC").merge(Developer.limit(2))
     assert_present devs.locked
   end
 
   def test_relation_merging_with_preload
-    [Post.scoped & Post.preload(:author), Post.preload(:author) & Post.scoped].each do |posts|
-      assert_queries(2) { assert posts.first.author }
+    ActiveRecord::IdentityMap.without do
+      [Post.scoped.merge(Post.preload(:author)), Post.preload(:author).merge(Post.scoped)].each do |posts|
+        assert_queries(2) { assert posts.first.author }
+      end
     end
   end
 
   def test_relation_merging_with_joins
-    comments = Comment.joins(:post).where(:body => 'Thank you for the welcome') & Post.where(:body => 'Such a lovely day')
+    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
 
@@ -630,6 +676,14 @@ class RelationTest < ActiveRecord::TestCase
   def test_any
     posts = Post.scoped
 
+    # 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?
@@ -754,7 +808,7 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal 'zyke', FastCar.order('name desc').find(:first, :order => 'id').name
   end
 
-  def test_default_scope_order_with_named_scope_order
+  def test_default_scope_order_with_scope_order
     assert_equal 'zyke', CoolCar.order_using_new_style.limit(1).first.name
     assert_equal 'zyke', CoolCar.order_using_old_style.limit(1).first.name
     assert_equal 'zyke', FastCar.order_using_new_style.limit(1).first.name
@@ -788,4 +842,12 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal [rails_author], [rails_author] & relation
     assert_equal [rails_author], relation & [rails_author]
   end
+
+  def test_removing_limit_with_options
+    assert_not_equal 1, Post.limit(1).all(:limit => nil).count
+  end
+
+  def test_primary_key
+    assert_equal "id", Post.scoped.primary_key
+  end
 end
diff --git a/activerecord/test/cases/serialization_test.rb b/activerecord/test/cases/serialization_test.rb
index 25dbcc9fc2..677d659f39 100644
--- a/activerecord/test/cases/serialization_test.rb
+++ b/activerecord/test/cases/serialization_test.rb
@@ -23,6 +23,12 @@ class SerializationTest < ActiveRecord::TestCase
     @contact = Contact.new(@contact_attributes)
   end
 
+  def test_serialized_init_with
+    topic = Topic.allocate
+    topic.init_with('attributes' => { 'content' => '--- foo' })
+    assert_equal 'foo', topic.content
+  end
+
   def test_to_xml
     xml = REXML::Document.new(topics(:first).to_xml(:indent => 0))
     bonus_time_in_current_timezone = topics(:first).bonus_time.xmlschema
diff --git a/activerecord/test/cases/session_store/session_test.rb b/activerecord/test/cases/session_store/session_test.rb
index 6f1c170a0c..cee5ddd003 100644
--- a/activerecord/test/cases/session_store/session_test.rb
+++ b/activerecord/test/cases/session_store/session_test.rb
@@ -5,7 +5,7 @@ require 'active_record/session_store'
 module ActiveRecord
   class SessionStore
     class SessionTest < ActiveRecord::TestCase
-      self.use_transactional_fixtures = false
+      self.use_transactional_fixtures = false unless supports_savepoints? && ActiveRecord::Base.connection.supports_ddl_transactions?
 
       def setup
         super
@@ -60,6 +60,7 @@ module ActiveRecord
       end
 
       def test_loaded?
+        Session.create_table!
         s = Session.new
         assert !s.loaded?, 'session is not loaded'
       end
diff --git a/activerecord/test/cases/timestamp_test.rb b/activerecord/test/cases/timestamp_test.rb
index 70c098bc6d..1c21f0f3b6 100644
--- a/activerecord/test/cases/timestamp_test.rb
+++ b/activerecord/test/cases/timestamp_test.rb
@@ -140,4 +140,34 @@ class TimestampTest < ActiveRecord::TestCase
   ensure
     Toy.belongs_to :pet
   end
+
+  def test_timestamp_attributes_for_create
+    toy = Toy.first
+    assert_equal toy.send(:timestamp_attributes_for_create), [:created_at, :created_on]
+  end
+
+  def test_timestamp_attributes_for_update
+    toy = Toy.first
+    assert_equal toy.send(:timestamp_attributes_for_update), [:updated_at, :updated_on]
+  end
+
+  def test_all_timestamp_attributes
+    toy = Toy.first
+    assert_equal toy.send(:all_timestamp_attributes), [:created_at, :created_on, :updated_at, :updated_on]
+  end
+
+  def test_timestamp_attributes_for_create_in_model
+    toy = Toy.first
+    assert_equal toy.send(:timestamp_attributes_for_create_in_model), [:created_at]
+  end
+
+  def test_timestamp_attributes_for_update_in_model
+    toy = Toy.first
+    assert_equal toy.send(:timestamp_attributes_for_update_in_model), [:updated_at]
+  end
+
+  def test_all_timestamp_attributes_in_model
+    toy = Toy.first
+    assert_equal toy.send(:all_timestamp_attributes_in_model), [:created_at, :updated_at]
+  end
 end
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
index b0ccd71836..110a18772f 100644
--- a/activerecord/test/cases/transactions_test.rb
+++ b/activerecord/test/cases/transactions_test.rb
@@ -370,23 +370,23 @@ class TransactionTest < ActiveRecord::TestCase
       assert topic_2.save
       @first.save
       @second.destroy
-      assert_equal true, topic_1.persisted?
+      assert topic_1.persisted?, 'persisted'
       assert_not_nil topic_1.id
-      assert_equal true, topic_2.persisted?
+      assert topic_2.persisted?, 'persisted'
       assert_not_nil topic_2.id
-      assert_equal true, @first.persisted?
+      assert @first.persisted?, 'persisted'
       assert_not_nil @first.id
-      assert_equal true, @second.destroyed?
+      assert @second.destroyed?, 'destroyed'
       raise ActiveRecord::Rollback
     end
 
-    assert_equal false, topic_1.persisted?
+    assert !topic_1.persisted?, 'not persisted'
     assert_nil topic_1.id
-    assert_equal false, topic_2.persisted?
+    assert !topic_2.persisted?, 'not persisted'
     assert_nil topic_2.id
-    assert_equal true, @first.persisted?
+    assert @first.persisted?, 'persisted'
     assert_not_nil @first.id
-    assert_equal false, @second.destroyed?
+    assert !@second.destroyed?, 'not destroyed'
   end
 
   if current_adapter?(:PostgreSQLAdapter) && defined?(PGconn::PQTRANS_IDLE)
diff --git a/activerecord/test/cases/unconnected_test.rb b/activerecord/test/cases/unconnected_test.rb
index 23ad10f3f9..f85fb4e5da 100644
--- a/activerecord/test/cases/unconnected_test.rb
+++ b/activerecord/test/cases/unconnected_test.rb
@@ -4,7 +4,7 @@ class TestRecord < ActiveRecord::Base
 end
 
 class TestUnconnectedAdapter < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+  self.use_transactional_fixtures = false unless supports_savepoints?
 
   def setup
     @underlying = ActiveRecord::Base.connection
@@ -14,6 +14,7 @@ class TestUnconnectedAdapter < ActiveRecord::TestCase
   def teardown
     @underlying = nil
     ActiveRecord::Base.establish_connection(@specification)
+    load_schema if in_memory_db?
   end
 
   def test_connection_no_longer_established
diff --git a/activerecord/test/cases/validations/uniqueness_validation_test.rb b/activerecord/test/cases/validations/uniqueness_validation_test.rb
index 679d67553b..b4f3dd034c 100644
--- a/activerecord/test/cases/validations/uniqueness_validation_test.rb
+++ b/activerecord/test/cases/validations/uniqueness_validation_test.rb
@@ -6,19 +6,6 @@ require 'models/warehouse_thing'
 require 'models/guid'
 require 'models/event'
 
-# The following methods in Topic are used in test_conditional_validation_*
-class Topic
-  has_many :unique_replies, :dependent => :destroy, :foreign_key => "parent_id"
-  has_many :silly_unique_replies, :dependent => :destroy, :foreign_key => "parent_id"
-end
-
-class UniqueReply < Reply
-  validates_uniqueness_of :content, :scope => 'parent_id'
-end
-
-class SillyUniqueReply < UniqueReply
-end
-
 class Wizard < ActiveRecord::Base
   self.abstract_class = true
 
diff --git a/activerecord/test/cases/xml_serialization_test.rb b/activerecord/test/cases/xml_serialization_test.rb
index 2003e25e35..a6074b23e7 100644
--- a/activerecord/test/cases/xml_serialization_test.rb
+++ b/activerecord/test/cases/xml_serialization_test.rb
@@ -262,4 +262,10 @@ class DatabaseConnectedXmlSerializationTest < ActiveRecord::TestCase
     assert array.include? 'github'
   end
 
+  def test_should_support_aliased_attributes
+    xml = Author.select("name as firstname").to_xml
+    array = Hash.from_xml(xml)['authors']
+    assert_equal array.size, array.select { |author| author.has_key? 'firstname' }.size
+  end
+
 end
diff --git a/activerecord/test/cases/yaml_serialization_test.rb b/activerecord/test/cases/yaml_serialization_test.rb
index 0fc9918744..0b54c309d1 100644
--- a/activerecord/test/cases/yaml_serialization_test.rb
+++ b/activerecord/test/cases/yaml_serialization_test.rb
@@ -17,4 +17,30 @@ class YamlSerializationTest < ActiveRecord::TestCase
     t = YAML.load YAML.dump topic
     assert_equal topic, t
   end
+
+  def test_encode_with_coder
+    topic = Topic.first
+    coder = {}
+    topic.encode_with coder
+    assert_equal({'attributes' => topic.attributes}, coder)
+  end
+
+  begin
+    require 'psych'
+
+    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
+  rescue LoadError
+  end
 end
diff --git a/activerecord/test/connections/native_sqlite3/connection.rb b/activerecord/test/connections/native_sqlite3/connection.rb
index c517c2375e..c2aff5551f 100644
--- a/activerecord/test/connections/native_sqlite3/connection.rb
+++ b/activerecord/test/connections/native_sqlite3/connection.rb
@@ -3,21 +3,12 @@ require_dependency 'models/course'
 require 'logger'
 ActiveRecord::Base.logger = Logger.new("debug.log")
 
-class SqliteError < StandardError
-end
-
 BASE_DIR = FIXTURES_ROOT
 sqlite_test_db  = "#{BASE_DIR}/fixture_database.sqlite3"
 sqlite_test_db2 = "#{BASE_DIR}/fixture_database_2.sqlite3"
 
 def make_connection(clazz, db_file)
   ActiveRecord::Base.configurations = { clazz.name => { :adapter => 'sqlite3', :database => db_file, :timeout => 5000 } }
-  unless File.exist?(db_file)
-    puts "SQLite3 database not found at #{db_file}. Rebuilding it."
-    sqlite_command = %Q{sqlite3 "#{db_file}" "create table a (a integer); drop table a;"}
-    puts "Executing '#{sqlite_command}'"
-    raise SqliteError.new("Seems that there is no sqlite3 executable available") unless system(sqlite_command)
-  end
   clazz.establish_connection(clazz.name)
 end
 
diff --git a/activerecord/test/connections/native_sqlite3/in_memory_connection.rb b/activerecord/test/connections/native_sqlite3/in_memory_connection.rb
deleted file mode 100644
index 6aba9719bb..0000000000
--- a/activerecord/test/connections/native_sqlite3/in_memory_connection.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-print "Using native SQLite3\n"
-require_dependency 'models/course'
-require 'logger'
-ActiveRecord::Base.logger = Logger.new("debug.log")
-
-class SqliteError < StandardError
-end
-
-def make_connection(clazz, db_definitions_file)
-  clazz.establish_connection(:adapter => 'sqlite3', :database  => ':memory:')
-  File.read(SCHEMA_ROOT + "/#{db_definitions_file}").split(';').each do |command|
-    clazz.connection.execute(command) unless command.strip.empty?
-  end
-end
-
-make_connection(ActiveRecord::Base, 'sqlite.sql')
-make_connection(Course, 'sqlite2.sql')
-load(SCHEMA_ROOT + "/schema.rb")
diff --git a/activerecord/test/connections/native_sqlite3_mem/connection.rb b/activerecord/test/connections/native_sqlite3_mem/connection.rb
new file mode 100644
index 0000000000..14e10900d1
--- /dev/null
+++ b/activerecord/test/connections/native_sqlite3_mem/connection.rb
@@ -0,0 +1,19 @@
+# This file connects to an in-memory SQLite3 database, which is a very fast way to run the tests.
+# The downside is that disconnect from the database results in the database effectively being
+# wiped. For this reason, pooled_connections_test.rb is disabled when using an in-memory database.
+
+print "Using native SQLite3 (in memory)\n"
+require_dependency 'models/course'
+require 'logger'
+ActiveRecord::Base.logger = Logger.new("debug.log")
+
+class SqliteError < StandardError
+end
+
+def make_connection(clazz)
+  ActiveRecord::Base.configurations = { clazz.name => { :adapter => 'sqlite3', :database  => ':memory:' } }
+  clazz.establish_connection(clazz.name)
+end
+
+make_connection(ActiveRecord::Base)
+make_connection(Course)
diff --git a/activerecord/test/fixtures/companies.yml b/activerecord/test/fixtures/companies.yml
index ffaa097686..a982d3921d 100644
--- a/activerecord/test/fixtures/companies.yml
+++ b/activerecord/test/fixtures/companies.yml
@@ -12,6 +12,7 @@ first_firm:
   type: Firm
   name: 37signals
   ruby_type: Firm
+  firm_id: 1
 
 second_client:
   id: 3
diff --git a/activerecord/test/fixtures/dashboards.yml b/activerecord/test/fixtures/dashboards.yml
index e75bf46e6c..a4c7e0d309 100644
--- a/activerecord/test/fixtures/dashboards.yml
+++ b/activerecord/test/fixtures/dashboards.yml
@@ -1,3 +1,6 @@
 cool_first:
   dashboard_id: d1
-  name: my_dashboard
\ No newline at end of file
+  name: my_dashboard
+second:
+  dashboard_id: d2
+  name: second
diff --git a/activerecord/test/fixtures/posts.yml b/activerecord/test/fixtures/posts.yml
index 264ca164f0..7298096025 100644
--- a/activerecord/test/fixtures/posts.yml
+++ b/activerecord/test/fixtures/posts.yml
@@ -5,6 +5,7 @@ welcome:
   body: Such a lovely day
   comments_count: 2
   taggings_count: 1
+  tags_count: 1
   type: Post
 
 thinking:
@@ -14,6 +15,7 @@ thinking:
   body: Like I hopefully always am
   comments_count: 1
   taggings_count: 1
+  tags_count: 1
   type: SpecialPost
 
 authorless:
diff --git a/activerecord/test/fixtures/ships.yml b/activerecord/test/fixtures/ships.yml
index 137055aad1..df914262b3 100644
--- a/activerecord/test/fixtures/ships.yml
+++ b/activerecord/test/fixtures/ships.yml
@@ -1,5 +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
index 6a471aba0a..e12398f0c4 100644
--- a/activerecord/test/fixtures/speedometers.yml
+++ b/activerecord/test/fixtures/speedometers.yml
@@ -1,4 +1,8 @@
 cool_first:
   speedometer_id: s1
   name: my_speedometer
-  dashboard_id: d1
\ No newline at end of file
+  dashboard_id: d1
+second:
+  speedometer_id: s2
+  name: second
+  dashboard_id: d2
diff --git a/activerecord/test/fixtures/subscribers.yml b/activerecord/test/fixtures/subscribers.yml
index 9ffb4a156f..c6a8c2fa24 100644
--- a/activerecord/test/fixtures/subscribers.yml
+++ b/activerecord/test/fixtures/subscribers.yml
@@ -5,3 +5,7 @@ first:
 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/traffic_lights.yml b/activerecord/test/fixtures/traffic_lights.yml
new file mode 100644
index 0000000000..6dabd53474
--- /dev/null
+++ b/activerecord/test/fixtures/traffic_lights.yml
@@ -0,0 +1,6 @@
+uk:
+  location: UK
+  state:
+    - Green
+    - Red
+    - Orange
diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
index 43bfd93e60..f362f70dec 100644
--- a/activerecord/test/models/author.rb
+++ b/activerecord/test/models/author.rb
@@ -26,6 +26,12 @@ class Author < ActiveRecord::Base
   has_many :comments_with_order_and_conditions, :through => :posts, :source => :comments, :order => 'comments.body', :conditions => "comments.body like 'Thank%'"
   has_many :comments_with_include, :through => :posts, :source => :comments, :include => :post
 
+  has_many :first_posts
+  has_many :comments_on_first_posts, :through => :first_posts, :source => :comments, :order => 'posts.id desc, comments.id asc'
+
+  has_one :first_post
+  has_one :comment_on_first_post,  :through => :first_post, :source => :comments, :order => 'posts.id desc, comments.id asc'
+
   has_many :thinking_posts, :class_name => 'Post', :conditions => { :title => 'So I was thinking' }, :dependent => :delete_all
   has_many :welcome_posts,  :class_name => 'Post', :conditions => { :title => 'Welcome to the weblog' }
 
@@ -72,6 +78,11 @@ class Author < ActiveRecord::Base
 
   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, :through => :categorizations, :source => :category, :class_name => 'Category', :conditions => { :name => 'General' }
 
diff --git a/activerecord/test/models/bulb.rb b/activerecord/test/models/bulb.rb
index 9eefc5803a..7178bb0d00 100644
--- a/activerecord/test/models/bulb.rb
+++ b/activerecord/test/models/bulb.rb
@@ -1,7 +1,14 @@
 class Bulb < ActiveRecord::Base
-  
+
   default_scope :conditions => {:name => 'defaulty' }
-  
+
   belongs_to :car
 
+  attr_reader :scoped_methods_after_initialize
+
+  after_initialize :record_scoped_methods_after_initialize
+  def record_scoped_methods_after_initialize
+    @scoped_methods_after_initialize = self.class.scoped_methods.dup
+  end
+
 end
diff --git a/activerecord/test/models/categorization.rb b/activerecord/test/models/categorization.rb
index 8e2fa96498..09489b8ea4 100644
--- a/activerecord/test/models/categorization.rb
+++ b/activerecord/test/models/categorization.rb
@@ -1,7 +1,20 @@
 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
index 95825c72ef..02b85fd38a 100644
--- a/activerecord/test/models/category.rb
+++ b/activerecord/test/models/category.rb
@@ -22,9 +22,12 @@ class Category < ActiveRecord::Base
   end
 
   has_many :categorizations
-  has_many :authors, :through => :categorizations, :select => 'authors.*, categorizations.post_id'
-
   has_many :post_comments, :through => :posts, :source => :comments
+
+  has_many :authors, :through => :categorizations
+  has_many :authors_with_select, :through => :categorizations, :source => :author, :select => 'authors.*, categorizations.post_id'
+
+  scope :general, :conditions => { :name => 'General' }
 end
 
 class SpecialCategory < Category
diff --git a/activerecord/test/models/club.rb b/activerecord/test/models/club.rb
index 83d6b1b15a..24a65b0f2f 100644
--- a/activerecord/test/models/club.rb
+++ b/activerecord/test/models/club.rb
@@ -1,4 +1,5 @@
 class Club < ActiveRecord::Base
+  has_one :membership
   has_many :memberships
   has_many :members, :through => :memberships
   has_many :current_memberships
diff --git a/activerecord/test/models/comment.rb b/activerecord/test/models/comment.rb
index 1a3fb42b66..2a4c37089a 100644
--- a/activerecord/test/models/comment.rb
+++ b/activerecord/test/models/comment.rb
@@ -1,6 +1,7 @@
 class Comment < ActiveRecord::Base
   scope :limit_by, lambda {|l| limit(l) }
   scope :containing_the_letter_e, :conditions => "comments.body LIKE '%e%'"
+  scope :not_again, where("comments.body NOT LIKE '%again%'")
   scope :for_first_post, :conditions => { :post_id => 1 }
   scope :for_first_author,
               :joins => :post,
@@ -16,6 +17,11 @@ class Comment < ActiveRecord::Base
   def self.search_by_type(q)
     self.find(:all, :conditions => ["#{QUOTED_TYPE} = ?", q])
   end
+
+  def self.all_as_method
+    all
+  end
+  scope :all_as_scope, {}
 end
 
 class SpecialComment < Comment
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
index ee5f77b613..e0b30efd51 100644
--- a/activerecord/test/models/company.rb
+++ b/activerecord/test/models/company.rb
@@ -38,7 +38,9 @@ end
 class Firm < Company
   has_many :clients, :order => "id", :dependent => :destroy, :counter_sql =>
       "SELECT COUNT(*) FROM companies WHERE firm_id = 1 " +
-      "AND (#{QUOTED_TYPE} = 'Client' OR #{QUOTED_TYPE} = 'SpecialClient' OR #{QUOTED_TYPE} = 'VerySpecialClient' )"
+      "AND (#{QUOTED_TYPE} = 'Client' OR #{QUOTED_TYPE} = 'SpecialClient' OR #{QUOTED_TYPE} = 'VerySpecialClient' )",
+      :before_remove => :log_before_remove,
+      :after_remove  => :log_after_remove
   has_many :unsorted_clients, :class_name => "Client"
   has_many :clients_sorted_desc, :class_name => "Client", :order => "id DESC"
   has_many :clients_of_firm, :foreign_key => "client_of", :class_name => "Client", :order => "id"
@@ -46,20 +48,16 @@ class Firm < Company
   has_many :dependent_clients_of_firm, :foreign_key => "client_of", :class_name => "Client", :order => "id", :dependent => :destroy
   has_many :exclusively_dependent_clients_of_firm, :foreign_key => "client_of", :class_name => "Client", :order => "id", :dependent => :delete_all
   has_many :limited_clients, :class_name => "Client", :limit => 1
+  has_many :clients_with_interpolated_conditions, :class_name => "Client", :conditions => proc { "rating > #{rating}" }
   has_many :clients_like_ms, :conditions => "name = 'Microsoft'", :class_name => "Client", :order => "id"
-  has_many :clients_with_interpolated_conditions, :class_name => "Client", :conditions => 'rating > #{rating}'
   has_many :clients_like_ms_with_hash_conditions, :conditions => { :name => 'Microsoft' }, :class_name => "Client", :order => "id"
-  has_many :clients_using_sql, :class_name => "Client", :finder_sql => 'SELECT * FROM companies WHERE client_of = #{id}'
-  has_many :clients_using_multiline_sql, :class_name => "Client", :finder_sql => '
-  SELECT
-  companies.*
-  FROM companies WHERE companies.client_of = #{id}'
+  has_many :clients_using_sql, :class_name => "Client", :finder_sql => proc { "SELECT * FROM companies WHERE client_of = #{id}" }
   has_many :clients_using_counter_sql, :class_name => "Client",
-           :finder_sql  => 'SELECT * FROM companies WHERE client_of = #{id}',
-           :counter_sql => 'SELECT COUNT(*) FROM companies WHERE client_of = #{id}'
+           :finder_sql  => proc { "SELECT * FROM companies WHERE client_of = #{id} " },
+           :counter_sql => proc { "SELECT COUNT(*) FROM companies WHERE client_of = #{id}" }
   has_many :clients_using_zero_counter_sql, :class_name => "Client",
-           :finder_sql  => 'SELECT * FROM companies WHERE client_of = #{id}',
-           :counter_sql => 'SELECT 0 FROM companies WHERE client_of = #{id}'
+           :finder_sql  => proc { "SELECT * FROM companies WHERE client_of = #{id}" },
+           :counter_sql => proc { "SELECT 0 FROM companies WHERE client_of = #{id}" }
   has_many :no_clients_using_counter_sql, :class_name => "Client",
            :finder_sql  => 'SELECT * FROM companies WHERE client_of = 1000',
            :counter_sql => 'SELECT COUNT(*) FROM companies WHERE client_of = 1000'
@@ -88,6 +86,19 @@ class Firm < Company
   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
+
+  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
@@ -109,6 +120,9 @@ class Client < Company
   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, :class_name => "Firm", :foreign_key => "firm_id", :readonly => true
+  belongs_to :bob_firm, :class_name => "Firm", :foreign_key => "client_of", :conditions => { :name => "Bob" }
+  has_many :accounts, :through => :firm
+  belongs_to :account
 
   # Record destruction so we can test whether firm.clients.clear has
   # is calling client.destroy, deleting from the database, or setting
diff --git a/activerecord/test/models/contact.rb b/activerecord/test/models/contact.rb
index 975a885331..e081eee661 100644
--- a/activerecord/test/models/contact.rb
+++ b/activerecord/test/models/contact.rb
@@ -1,8 +1,14 @@
 class Contact < ActiveRecord::Base
+  establish_connection(:adapter => 'fake')
+
+  connection.tables = ['contacts']
+  connection.primary_keys = {
+    'contacts' => 'id'
+  }
+
   # mock out self.columns so no pesky db is needed for these tests
   def self.column(name, sql_type = nil, options = {})
-    @columns ||= []
-    @columns << ActiveRecord::ConnectionAdapters::Column.new(name.to_s, options[:default], sql_type.to_s, options[:null])
+    connection.merge_column('contacts', name, sql_type, options)
   end
 
   column :name,        :string
diff --git a/activerecord/test/models/contract.rb b/activerecord/test/models/contract.rb
index 606c99cd4e..94fd48e12a 100644
--- a/activerecord/test/models/contract.rb
+++ b/activerecord/test/models/contract.rb
@@ -1,4 +1,4 @@
 class Contract < ActiveRecord::Base
   belongs_to :company
   belongs_to :developer
-end
\ No newline at end of file
+end
diff --git a/activerecord/test/models/customer.rb b/activerecord/test/models/customer.rb
index e258ccdb6c..777f6b5ba0 100644
--- a/activerecord/test/models/customer.rb
+++ b/activerecord/test/models/customer.rb
@@ -70,4 +70,4 @@ class Fullname
   def to_s
     "#{first} #{last.upcase}"
   end
-end
\ No newline at end of file
+end
diff --git a/activerecord/test/models/joke.rb b/activerecord/test/models/joke.rb
index 3978abc2ba..d7f01e59e6 100644
--- a/activerecord/test/models/joke.rb
+++ b/activerecord/test/models/joke.rb
@@ -1,3 +1,7 @@
 class Joke < ActiveRecord::Base
   set_table_name 'funny_jokes'
 end
+
+class GoodJoke < ActiveRecord::Base
+  set_table_name 'funny_jokes'
+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/member.rb b/activerecord/test/models/member.rb
index fbf0b80164..991e0e051f 100644
--- a/activerecord/test/models/member.rb
+++ b/activerecord/test/models/member.rb
@@ -1,9 +1,10 @@
 class Member < ActiveRecord::Base
   has_one :current_membership
-  has_many :memberships
+  has_one :membership
   has_many :fellow_members, :through => :club, :source => :members
   has_one :club, :through => :current_membership
-  has_one :favourite_club, :through => :memberships, :conditions => ["memberships.favourite = ?", true], :source => :club
+  has_one :favourite_club, :through => :membership, :conditions => ["memberships.favourite = ?", true], :source => :club
+  has_one :hairy_club, :through => :membership, :conditions => {:clubs => {:name => "Moustache and Eyebrow Fancier Club"}}, :source => :club
   has_one :sponsor, :as => :sponsorable
   has_one :sponsor_club, :through => :sponsor
   has_one :member_detail
@@ -20,4 +21,10 @@ class Member < ActiveRecord::Base
   has_many :organization_member_details_2, :through => :organization, :source => :member_details
 
   has_one :club_category, :through => :club, :source => :category
+
+  has_many :current_memberships
+  has_one :club_through_many, :through => :current_memberships, :source => :club
+
+  has_many :current_memberships, :conditions => { :favourite => true }
+  has_many :clubs, :through => :current_memberships
 end
diff --git a/activerecord/test/models/person.rb b/activerecord/test/models/person.rb
index 5a5b6f9626..ad59d12672 100644
--- a/activerecord/test/models/person.rb
+++ b/activerecord/test/models/person.rb
@@ -1,17 +1,24 @@
 class Person < ActiveRecord::Base
   has_many :readers
+  has_one :reader
+
   has_many :posts, :through => :readers
   has_many :posts_with_no_comments, :through => :readers, :source => :post, :include => :comments, :conditions => 'comments.id is null'
 
   has_many :references
   has_many :bad_references
   has_many :fixed_bad_references, :conditions => { :favourite => true }, :class_name => 'BadReference'
-  has_many :jobs, :through => :references
   has_one :favourite_reference, :class_name => 'Reference', :conditions => ['favourite=?', true]
   has_many :posts_with_comments_sorted_by_comment_id, :through => :readers, :source => :post, :include => :comments, :order => 'comments.id'
 
+  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
@@ -20,3 +27,24 @@ class Person < ActiveRecord::Base
   scope :males, :conditions => { :gender => 'M' }
   scope :females, :conditions => { :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
diff --git a/activerecord/test/models/pirate.rb b/activerecord/test/models/pirate.rb
index f2c45053e7..0d3f62bb33 100644
--- a/activerecord/test/models/pirate.rb
+++ b/activerecord/test/models/pirate.rb
@@ -34,6 +34,8 @@ class Pirate < ActiveRecord::Base
     :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 :bulb, :foreign_key => :car_id
+
   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
@@ -78,3 +80,7 @@ class Pirate < ActiveRecord::Base
       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
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
index e9c8c02e45..b39325f949 100644
--- a/activerecord/test/models/post.rb
+++ b/activerecord/test/models/post.rb
@@ -38,9 +38,11 @@ class Post < ActiveRecord::Base
   end
 
   has_many :author_favorites, :through => :author
+  has_many :author_categorizations, :through => :author, :source => :categorizations
+  has_many :author_addresses, :through => :author
 
   has_many :comments_with_interpolated_conditions, :class_name => 'Comment',
-      :conditions => ['#{"#{aliased_table_name}." rescue ""}body = ?', 'Thank you for the welcome']
+    :conditions => proc { ["#{"#{aliased_table_name}." rescue ""}body = ?", 'Thank you for the welcome'] }
 
   has_one  :very_special_comment
   has_one  :very_special_comment_with_post, :class_name => "VerySpecialComment", :include => :post
@@ -55,11 +57,21 @@ class Post < ActiveRecord::Base
   has_many :taggings, :as => :taggable
   has_many :tags, :through => :taggings do
     def add_joins_and_select
-      find :all, :select => 'tags.*, authors.id as author_id', :include => false,
+      find :all, :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'
     end
   end
 
+  has_many :interpolated_taggings, :class_name => 'Tagging', :as => :taggable, :conditions => proc { "1 = #{1}" }
+  has_many :interpolated_tags, :through => :taggings
+  has_many :interpolated_tags_2, :through => :interpolated_taggings, :source => :tag
+
+  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, :through => :taggings, :source => :tag, :conditions => "tags.name = 'Misc'"
   has_many :funky_tags, :through => :taggings, :source => :tag
   has_many :super_tags, :through => :taggings
@@ -77,9 +89,21 @@ class Post < ActiveRecord::Base
   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 :readers_with_person, :include => :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) },
@@ -127,3 +151,10 @@ class PostForAuthor < ActiveRecord::Base
   cattr_accessor :selected_author
   default_scope lambda { where(:author_id => PostForAuthor.selected_author) }
 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
diff --git a/activerecord/test/models/project.rb b/activerecord/test/models/project.rb
index 416032cb75..efe1ce67da 100644
--- a/activerecord/test/models/project.rb
+++ b/activerecord/test/models/project.rb
@@ -7,14 +7,15 @@ class Project < ActiveRecord::Base
   has_and_belongs_to_many :developers_named_david, :class_name => "Developer", :conditions => "name = 'David'", :uniq => true
   has_and_belongs_to_many :developers_named_david_with_hash_conditions, :class_name => "Developer", :conditions => { :name => 'David' }, :uniq => true
   has_and_belongs_to_many :salaried_developers, :class_name => "Developer", :conditions => "salary > 0"
-  has_and_belongs_to_many :developers_with_finder_sql, :class_name => "Developer", :finder_sql => 'SELECT t.*, j.* FROM developers_projects j, developers t WHERE t.id = j.developer_id AND j.project_id = #{id} ORDER BY t.id'
-  has_and_belongs_to_many :developers_with_multiline_finder_sql, :class_name => "Developer", :finder_sql => '
-    SELECT
-      t.*, j.*
-    FROM
-      developers_projects j,
-      developers t WHERE t.id = j.developer_id AND j.project_id = #{id} ORDER BY t.id'
-  has_and_belongs_to_many :developers_by_sql, :class_name => "Developer", :delete_sql => "DELETE FROM developers_projects WHERE project_id = \#{id} AND developer_id = \#{record.id}"
+  has_and_belongs_to_many :developers_with_finder_sql, :class_name => "Developer", :finder_sql => proc { "SELECT t.*, j.* FROM developers_projects j, developers t WHERE t.id = j.developer_id AND j.project_id = #{id} ORDER BY t.id" }
+  has_and_belongs_to_many :developers_with_multiline_finder_sql, :class_name => "Developer", :finder_sql => proc {
+    "SELECT
+       t.*, j.*
+     FROM
+       developers_projects j,
+       developers t WHERE t.id = j.developer_id AND j.project_id = #{id} ORDER BY t.id"
+  }
+  has_and_belongs_to_many :developers_by_sql, :class_name => "Developer", :delete_sql => proc { |record| "DELETE FROM developers_projects WHERE project_id = #{id} AND developer_id = #{record.id}" }
   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}"},
@@ -28,6 +29,10 @@ class Project < ActiveRecord::Base
     @developers_log = []
   end
 
+  def self.all_as_method
+    all
+  end
+  scope :all_as_scope, {}
 end
 
 class SpecialProject < Project
diff --git a/activerecord/test/models/reader.rb b/activerecord/test/models/reader.rb
index 27527bf566..0207a2bd92 100644
--- a/activerecord/test/models/reader.rb
+++ b/activerecord/test/models/reader.rb
@@ -1,4 +1,5 @@
 class Reader < ActiveRecord::Base
   belongs_to :post
-  belongs_to :person
+  belongs_to :person, :inverse_of => :readers
+  belongs_to :single_person, :class_name => 'Person', :foreign_key => :person_id, :inverse_of => :reader
 end
diff --git a/activerecord/test/models/reference.rb b/activerecord/test/models/reference.rb
index 87d4a71963..e33a0f2acc 100644
--- a/activerecord/test/models/reference.rb
+++ b/activerecord/test/models/reference.rb
@@ -3,6 +3,18 @@ class Reference < ActiveRecord::Base
   belongs_to :job
 
   has_many :agents_posts_authors, :through => :person
+
+  class << self
+    attr_accessor :make_comments
+  end
+
+  before_destroy :make_comments
+
+  def make_comments
+    if self.class.make_comments
+      person.update_attributes :comments => "Reference destroyed"
+    end
+  end
 end
 
 class BadReference < ActiveRecord::Base
diff --git a/activerecord/test/models/reply.rb b/activerecord/test/models/reply.rb
index 110d540120..6adfe0ae3c 100644
--- a/activerecord/test/models/reply.rb
+++ b/activerecord/test/models/reply.rb
@@ -10,6 +10,13 @@ class Reply < Topic
   attr_accessible :title, :author_name, :author_email_address, :written_on, :content, :last_read, :parent_title
 end
 
+class UniqueReply < Reply
+  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
diff --git a/activerecord/test/models/sponsor.rb b/activerecord/test/models/sponsor.rb
index 50c2c2d76c..aa4a3638fd 100644
--- a/activerecord/test/models/sponsor.rb
+++ b/activerecord/test/models/sponsor.rb
@@ -1,4 +1,7 @@
 class Sponsor < ActiveRecord::Base
   belongs_to :sponsor_club, :class_name => "Club", :foreign_key => "club_id"
   belongs_to :sponsorable, :polymorphic => true
-end
\ No newline at end of file
+  belongs_to :thing, :polymorphic => true, :foreign_type => :sponsorable_type, :foreign_key => :sponsorable_id
+  belongs_to :sponsorable_with_conditions, :polymorphic => true,
+             :foreign_type => 'sponsorable_type', :foreign_key => 'sponsorable_id', :conditions => {:name => 'Ernie'}
+end
diff --git a/activerecord/test/models/student.rb b/activerecord/test/models/student.rb
new file mode 100644
index 0000000000..f459f2a9a3
--- /dev/null
+++ b/activerecord/test/models/student.rb
@@ -0,0 +1,3 @@
+class Student < ActiveRecord::Base
+  has_and_belongs_to_many :lessons
+end
diff --git a/activerecord/test/models/tagging.rb b/activerecord/test/models/tagging.rb
index c6ff8d390b..17e627a60e 100644
--- a/activerecord/test/models/tagging.rb
+++ b/activerecord/test/models/tagging.rb
@@ -8,5 +8,7 @@ class Tagging < ActiveRecord::Base
   belongs_to :invalid_tag, :class_name => 'Tag', :foreign_key => 'tag_id'
   belongs_to :blue_tag,    :class_name => 'Tag', :foreign_key => :tag_id, :conditions => "tags.name = 'Blue'"
   belongs_to :tag_with_primary_key, :class_name => 'Tag', :foreign_key => :tag_id, :primary_key => :custom_primary_key
+  belongs_to :interpolated_tag, :class_name => 'Tag', :foreign_key => :tag_id, :conditions => proc { "1 = #{1}" }
   belongs_to :taggable, :polymorphic => true, :counter_cache => true
+  has_many :things, :through => :taggable
 end
diff --git a/activerecord/test/models/task.rb b/activerecord/test/models/task.rb
index ee0282c79b..e36989dd56 100644
--- a/activerecord/test/models/task.rb
+++ b/activerecord/test/models/task.rb
@@ -1,3 +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
index 6496f36f7e..6440dbe8ab 100644
--- a/activerecord/test/models/topic.rb
+++ b/activerecord/test/models/topic.rb
@@ -45,6 +45,10 @@ class Topic < ActiveRecord::Base
 
   has_many :replies, :dependent => :destroy, :foreign_key => "parent_id"
   has_many :replies_with_primary_key, :class_name => "Reply", :dependent => :destroy, :primary_key => "title", :foreign_key => "parent_title"
+
+  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
diff --git a/activerecord/test/models/traffic_light.rb b/activerecord/test/models/traffic_light.rb
new file mode 100644
index 0000000000..228f3f7bd4
--- /dev/null
+++ b/activerecord/test/models/traffic_light.rb
@@ -0,0 +1,3 @@
+class TrafficLight < ActiveRecord::Base
+  serialize :state, Array
+end
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index 5deb233f2d..bdadd0698b 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -113,8 +113,10 @@ ActiveRecord::Schema.define do
 
   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|
@@ -145,6 +147,7 @@ ActiveRecord::Schema.define do
       t.text    :body, :null => false
     end
     t.string  :type
+    t.integer :taggings_count, :default => 0
   end
 
   create_table :companies, :force => true do |t|
@@ -155,6 +158,7 @@ ActiveRecord::Schema.define do
     t.string  :name
     t.integer :client_of
     t.integer :rating, :default => 1
+    t.integer :account_id
   end
 
   add_index :companies, [:firm_id, :type, :rating, :ruby_type], :name => "company_index"
@@ -231,6 +235,10 @@ ActiveRecord::Schema.define do
     t.string :name
   end
 
+  create_table :cold_jokes, :force => true do |t|
+    t.string :name
+  end
+
   create_table :goofy_string_id, :force => true, :id => false do |t|
     t.string :id, :null => false
     t.string :info
@@ -281,6 +289,15 @@ ActiveRecord::Schema.define do
     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 :line_items, :force => true do |t|
     t.integer :invoice_id
     t.integer :amount
@@ -419,6 +436,8 @@ ActiveRecord::Schema.define do
     t.string     :gender, :limit => 1
     t.references :number1_fan
     t.integer    :lock_version, :null => false, :default => 0
+    t.string     :comments
+    t.timestamps
   end
 
   create_table :pets, :primary_key => :pet_id ,:force => true do |t|
@@ -447,6 +466,11 @@ ActiveRecord::Schema.define do
     t.string  :type
     t.integer :comments_count, :default => 0
     t.integer :taggings_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|
@@ -516,6 +540,10 @@ ActiveRecord::Schema.define do
     t.string :sponsorable_type
   end
 
+  create_table :students, :force => true do |t|
+    t.string :name
+  end
+
   create_table :subscribers, :force => true, :id => false do |t|
     t.string :nick, :null => false
     t.string :name