Add foreign key functionality for Rails migrations and schema dumps. MySQL and PostgreSQL adapters supported.
As Rails gem (from GemCutter)
sudo gem install foreign_keys
As Rails plugin
script/plugin install git://github.com/perfectline/foreign_keys.git
Just place the FK statements in your migrations. The simplest example is:
add_foreign_key :albums, :user_id
The referenced table and column are decidec by using rails conventions, i.e this example would result in a foreign key from 'albums.user_id' to 'users.id' column.
You can additionally provide multiple options for cases where the association information cannot be decided by conventions.
add_foreign_key :albums, :author_id, :references => :users, :keys => :user_id, :name => "my_special_fk"
Removing foreign keys is just as easy. You can remove them either by providing the constraint name or column(s).
remove_foreign_key :albums, :user_id
remove_foreign_key :albums, :name => "my_special_fk"
Note: MySQL creates an index on the FK column automatically. Removing a FK will remove that index also.
- references: name of the references table
- keys: column name(s) on the references table
- on_delete: on delete hook with a value of
:restrict,:set_null,:cascade - on_update: on update hook with a value of
:restrict,:set_null,:cascade - name: foreign key constraint name
The usual rake targets for db:schema:dump, db:schema:load, and db:reset
should all work as desired.
Tanel Suurhans - tanel.suurhans_at_perfectline.ee Tarmo Lehtpuu - tarmo.lehtpuu_at_perfectline.ee
This gem is based ideas and enhanchements from Dan Walters "foreign_keys" plugin-
Copyright 2009 by PerfectLine LLC (http://www.perfectline.co.uk) and is released under the MIT license.