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schema_statements.rb
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schema_statements.rb
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module Foreigner
module ConnectionAdapters
module SchemaStatements
def self.included(base)
base::AbstractAdapter.class_eval do
include Foreigner::ConnectionAdapters::AbstractAdapter
end
end
end
module AbstractAdapter
def create_table(table_name, *args, &block)
definition = nil
super do |td|
definition = td # This is my trick to get the definition
block.call(td)
end
definition.foreign_keys.each { |c,o| add_foreign_key table_name, c, o }
end
def supports_foreign_keys?
false
end
# 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
# <tt>:name</tt> 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 <tt>:column</tt>.
# [: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 <tt>:delete</tt>, the associated records in from_table are deleted when records in to_table table are deleted.
# If set to <tt>:nullify</tt>, the foreign key column is set to +NULL+.
# [:options]
# Any extra options you want appended to the foreign key definition.
def add_foreign_key(from_table, to_table, options = {})
end
# 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
def remove_foreign_key(from_table, options)
end
# Return the foreign keys for the schema_dumper
def foreign_keys(table_name)
[]
end
end
end
end