* Add an `:if_not_exists` option to `create_table`.
Example:
create_table :posts, if_not_exists: true do |t|
t.string :title
end
That would execute:
CREATE TABLE IF NOT EXISTS posts (
...
)
If the table already exists, `if_not_exists: false` (the default) raises an
exception whereas `if_not_exists: true` does nothing.
*fatkodima*, *Stefan Kanev*
* Defining an Enum as a Hash with blank key, or as an Array with a blank value, now raises an `ArgumentError`.
*Christophe Maximin*
* Adds support for multiple databases to `rails db:schema:cache:dump` and `rails db:schema:cache:clear`.
*Gannon McGibbon*
* `update_columns` now correctly raises `ActiveModel::MissingAttributeError`
if the attribute does not exist.
*Sean Griffin*
* Add support for hash and url configs in database hash of `ActiveRecord::Base.connected_to`.
````
User.connected_to(database: { writing: "postgres://foo" }) do
User.create!(name: "Gannon")
end
config = { "adapter" => "sqlite3", "database" => "db/readonly.sqlite3" }
User.connected_to(database: { reading: config }) do
User.count
end
````
*Gannon McGibbon*
* Support default expression for MySQL.
MySQL 8.0.13 and higher supports default value to be a function or expression.
https://dev.mysql.com/doc/refman/8.0/en/create-table.html
*Ryuta Kamizono*
* Support expression indexes for MySQL.
MySQL 8.0.13 and higher supports functional key parts that index
expression values rather than column or column prefix values.
https://dev.mysql.com/doc/refman/8.0/en/create-index.html
*Ryuta Kamizono*
* Fix collection cache key with limit and custom select to avoid ambiguous timestamp column error.
Fixes #33056.
*Federico Martinez*
* Add basic API for connection switching to support multiple databases.
1) Adds a `connects_to` method for models to connect to multiple databases. Example:
```
class AnimalsModel < ApplicationRecord
self.abstract_class = true
connects_to database: { writing: :animals_primary, reading: :animals_replica }
end
class Dog < AnimalsModel
# connected to both the animals_primary db for writing and the animals_replica for reading
end
```
2) Adds a `connected_to` block method for switching connection roles or connecting to
a database that the model didn't connect to. Connecting to the database in this block is
useful when you have another defined connection, for example `slow_replica` that you don't
want to connect to by default but need in the console, or a specific code block.
```
ActiveRecord::Base.connected_to(role: :reading) do
Dog.first # finds dog from replica connected to AnimalsBase
Book.first # doesn't have a reading connection, will raise an error
end
```
```
ActiveRecord::Base.connected_to(database: :slow_replica) do
SlowReplicaModel.first # if the db config has a slow_replica configuration this will be used to do the lookup, otherwise this will throw an exception
end
```
*Eileen M. Uchitelle*
* Enum raises on invalid definition values
When defining a Hash enum it can be easy to use [] instead of {}. This
commit checks that only valid definition values are provided, those can
be a Hash, an array of Symbols or an array of Strings. Otherwise it
raises an ArgumentError.
Fixes #33961
*Alberto Almagro*
* Reloading associations now clears the Query Cache like `Persistence#reload` does.
```
class Post < ActiveRecord::Base
has_one :category
belongs_to :author
has_many :comments
end
# Each of the following will now clear the query cache.
post.reload_category
post.reload_author
post.comments.reload
```
*Christophe Maximin*
* Added `index` option for `change_table` migration helpers.
With this change you can create indexes while adding new
columns into the existing tables.
Example:
change_table(:languages) do |t|
t.string :country_code, index: true
end
*Mehmet Emin İNAÇ*
* Fix `transaction` reverting for migrations.
Before: Commands inside a `transaction` in a reverted migration ran uninverted.
Now: This change fixes that by reverting commands inside `transaction` block.
*fatkodima*, *David Verhasselt*
* Raise an error instead of scanning the filesystem root when `fixture_path` is blank.
*Gannon McGibbon*, *Max Albrecht*
* Allow `ActiveRecord::Base.configurations=` to be set with a symbolized hash.
*Gannon McGibbon*
* Don't update counter cache unless the record is actually saved.
Fixes #31493, #33113, #33117.
*Ryuta Kamizono*
* Deprecate `ActiveRecord::Result#to_hash` in favor of `ActiveRecord::Result#to_a`.
*Gannon McGibbon*, *Kevin Cheng*
* SQLite3 adapter supports expression indexes.
```
create_table :users do |t|
t.string :email
end
add_index :users, 'lower(email)', name: 'index_users_on_email', unique: true
```
*Gray Kemmey*
* Allow subclasses to redefine autosave callbacks for associated records.
Fixes #33305.
*Andrey Subbota*
* Bump minimum MySQL version to 5.5.8.
*Yasuo Honda*
* Use MySQL utf8mb4 character set by default.
`utf8mb4` character set with 4-Byte encoding supports supplementary characters including emoji.
The previous default 3-Byte encoding character set `utf8` is not enough to support them.
*Yasuo Honda*
* Fix duplicated record creation when using nested attributes with `create_with`.
*Darwin Wu*
* Configuration item `config.filter_parameters` could also filter out
sensitive values of database columns when call `#inspect`.
We also added `ActiveRecord::Base::filter_attributes`/`=` in order to
specify sensitive attributes to specific model.
```
Rails.application.config.filter_parameters += [:credit_card_number, /phone/]
Account.last.inspect # => #<Account id: 123, name: "DHH", credit_card_number: [FILTERED], telephone_number: [FILTERED] ...>
SecureAccount.filter_attributes += [:name]
SecureAccount.last.inspect # => #<SecureAccount id: 42, name: [FILTERED], credit_card_number: [FILTERED] ...>
```
*Zhang Kang*, *Yoshiyuki Kinjo*
* Deprecate `column_name_length`, `table_name_length`, `columns_per_table`,
`indexes_per_table`, `columns_per_multicolumn_index`, `sql_query_length`,
and `joins_per_query` methods in `DatabaseLimits`.
*Ryuta Kamizono*
* `ActiveRecord::Base.configurations` now returns an object.
`ActiveRecord::Base.configurations` used to return a hash, but this
is an inflexible data model. In order to improve multiple-database
handling in Rails, we've changed this to return an object. Some methods
are provided to make the object behave hash-like in order to ease the
transition process. Since most applications don't manipulate the hash
we've decided to add backwards-compatible functionality that will throw
a deprecation warning if used, however calling `ActiveRecord::Base.configurations`
will use the new version internally and externally.
For example, the following `database.yml`:
```
development:
adapter: sqlite3
database: db/development.sqlite3
```
Used to become a hash:
```
{ "development" => { "adapter" => "sqlite3", "database" => "db/development.sqlite3" } }
```
Is now converted into the following object:
```
#<ActiveRecord::DatabaseConfigurations:0x00007fd1acbdf800 @configurations=[
#<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fd1acbded10 @env_name="development",
@spec_name="primary", @config={"adapter"=>"sqlite3", "database"=>"db/development.sqlite3"}>
]
```
Iterating over the database configurations has also changed. Instead of
calling hash methods on the `configurations` hash directly, a new method `configs_for` has
been provided that allows you to select the correct configuration. `env_name`, and
`spec_name` arguments are optional. For example these return an array of
database config objects for the requested environment and a single database config object
will be returned for the requested environment and specification name respectively.
```
ActiveRecord::Base.configurations.configs_for(env_name: "development")
ActiveRecord::Base.configurations.configs_for(env_name: "development", spec_name: "primary")
```
*Eileen M. Uchitelle*, *Aaron Patterson*
* Add database configuration to disable advisory locks.
```
production:
adapter: postgresql
advisory_locks: false
```
*Guo Xiang*
* SQLite3 adapter `alter_table` method restores foreign keys.
*Yasuo Honda*
* Allow `:to_table` option to `invert_remove_foreign_key`.
Example:
remove_foreign_key :accounts, to_table: :owners
*Nikolay Epifanov*, *Rich Chen*
* Add environment & load_config dependency to `bin/rake db:seed` to enable
seed load in environments without Rails and custom DB configuration
*Tobias Bielohlawek*
* Fix default value for mysql time types with specified precision.
*Nikolay Kondratyev*
* Fix `touch` option to behave consistently with `Persistence#touch` method.
*Ryuta Kamizono*
* Migrations raise when duplicate column definition.
Fixes #33024.
*Federico Martinez*
* Bump minimum SQLite version to 3.8
*Yasuo Honda*
* Fix parent record should not get saved with duplicate children records.
Fixes #32940.
*Santosh Wadghule*
* Fix logic on disabling commit callbacks so they are not called unexpectedly when errors occur.
*Brian Durand*
* Ensure `Associations::CollectionAssociation#size` and `Associations::CollectionAssociation#empty?`
use loaded association ids if present.
*Graham Turner*
* Add support to preload associations of polymorphic associations when not all the records have the requested associations.
*Dana Sherson*
* Add `touch_all` method to `ActiveRecord::Relation`.
Example:
Person.where(name: "David").touch_all(time: Time.new(2020, 5, 16, 0, 0, 0))
*fatkodima*, *duggiefresh*
* Add `ActiveRecord::Base.base_class?` predicate.
*Bogdan Gusiev*
* Add custom prefix/suffix options to `ActiveRecord::Store.store_accessor`.
*Tan Huynh*, *Yukio Mizuta*
* Rails 6 requires Ruby 2.4.1 or newer.
*Jeremy Daer*
* Deprecate `update_attributes`/`!` in favor of `update`/`!`.
*Eddie Lebow*
* Add `ActiveRecord::Base.create_or_find_by`/`!` to deal with the SELECT/INSERT race condition in
`ActiveRecord::Base.find_or_create_by`/`!` by leaning on unique constraints in the database.
*DHH*
* Add `Relation#pick` as short-hand for single-value plucks.
*DHH*
Please check [5-2-stable](https://github.com/rails/rails/blob/5-2-stable/activerecord/CHANGELOG.md) for previous changes.
