Foreign Keys

Add foreign key functionality for Rails migrations and schema dumps. MySQL and PostgreSQL adapters supported.

Installation

As Rails gem (from GemCutter)

sudo gem install foreign_keys

As Rails plugin

script/plugin install git://github.com/perfectline/foreign_keys.git

Quickstart

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.

Options

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

Schema Dump

The usual rake targets for db:schema:dump, db:schema:load, and db:reset should all work as desired.

Authors

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-