Module Foreigner::ConnectionAdapters::AbstractAdapter
In: lib/foreigner/connection_adapters/abstract/schema_statements.rb

Methods

Public Instance methods

Adds a new foreign key to the from_table, referencing the primary key of to_table

The foreign key will be named after the from and to tables unless you pass :name as an option.

Examples
Creating a foreign key
 add_foreign_key(:comments, :posts)

generates

 ALTER TABLE `comments` ADD CONSTRAINT
    `comments_post_id_fk` FOREIGN KEY (`post_id`) REFERENCES `posts` (`id`)
Creating a named foreign key
 add_foreign_key(:comments, :posts, :name => 'comments_belongs_to_posts')

generates

 ALTER TABLE `comments` ADD CONSTRAINT
    `comments_belongs_to_posts` FOREIGN KEY (`post_id`) REFERENCES `posts` (`id`)
Creating a cascading foreign_key on a custom column
 add_foreign_key(:people, :people, :column => 'best_friend_id', :dependent => :nullify)

generates

 ALTER TABLE `people` ADD CONSTRAINT
    `people_best_friend_id_fk` FOREIGN KEY (`best_friend_id`) REFERENCES `people` (`id`)
    ON DELETE SET NULL

Supported options

:column
Specify the column name on the from_table that references the to_table. By default this is guessed to be the singular name of the to_table with "_id" suffixed. So a to_table of :posts will use "post_id" as the default :column.
:primary_key
Specify the column name on the to_table that is referenced by this foreign key. By default this is assumed to be "id".
:name
Specify the name of the foreign key constraint. This defaults to use from_table and foreign key column.
:dependent
If set to :delete, the associated records in from_table are deleted when records in to_table table are deleted. If set to :nullify, the foreign key column is set to NULL.
:options
Any extra options you want appended to the foreign key definition.

Return the foreign keys for the schema_dumper

Remove the given foreign key from the table.

Examples
Remove the suppliers_company_id_fk in the suppliers table.
  remove_foreign_key :suppliers, :companies
Remove the foreign key named accounts_branch_id_fk in the accounts table.
  remove_foreign_key :accounts, :column => :branch_id
Remove the foreign key named party_foreign_key in the accounts table.
  remove_foreign_key :accounts, :name => :party_foreign_key

[Validate]