Skip to content

Adds foreign key helpers to migrations and correctly dumps foreign keys to schema.rb

License

Notifications You must be signed in to change notification settings

vizcay/foreigner

 
 

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Repository files navigation

Foreigner

<img src=“https://secure.travis-ci.org/matthuhiggins/foreigner.png?rvm=1.9.3” />

Foreigner introduces a few methods to your migrations for adding and removing foreign key constraints. It also dumps foreign keys to schema.rb.

The following adapters are supported:

  • mysql2

  • postgres

  • fb

  • sqlite (foreign key methods are a no-op)

Installation

Add the following to your Gemfile:

gem 'foreigner'

API Examples

Foreigner adds two methods to migrations.

  • add_foreign_key(from_table, to_table, options)

  • remove_foreign_key(from_table, options)

(Options are documented in connection_adapters/abstract/schema_definitions.rb):

For example, given the following model:

class Comment < ActiveRecord::Base
  belongs_to :post
end

class Post < ActiveRecord::Base
  has_many :comments, dependent: :delete_all
end

You should add a foreign key in your migration:

add_foreign_key(:comments, :posts)

The :dependent option can be moved from the has_many definition to the foreign key:

add_foreign_key(:comments, :posts, dependent: :delete)

If the column is named article_id instead of post_id, use the :column option:

add_foreign_key(:comments, :posts, column: 'article_id')

A name can be specified for the foreign key constraint:

add_foreign_key(:comments, :posts, name: 'comment_article_foreign_key')

Change Table Methods

Foreigner adds extra methods to create_table and change_table.

Create a new table with a foreign key:

create_table :products do |t|
  t.string :name
  t.integer :factory_id
  t.foreign_key :factories
end

Add a missing foreign key to comments:

change_table :comments do |t|
  t.foreign_key :posts, dependent: :delete
end

Remove an unwanted foreign key:

change_table :comments do |t|
  t.remove_foreign_key :users
end

Database specific options

Database specific options will never be supported by foreigner. You can add them using :options:

add_foreign_key(:comments, :posts, options: 'ON UPDATE DEFERRED')

Foreigner Add-ons

License

Copyright © 2012 Matthew Higgins, released under the MIT license

About

Adds foreign key helpers to migrations and correctly dumps foreign keys to schema.rb

Resources

License

Stars

Watchers

Forks

Packages

No packages published

Languages

  • Ruby 100.0%