Foreign Key Migrations in Rails 2.0

January 15th, 2008

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Before Rails 2.0, adding a foreign key column to your migration was easy:

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class CreateOfferGroupListings < ActiveRecord::Migration
  def self.up
    create_table :offer_group_listings do |t|
	  t.integer :offer_id
	  t.integer :offer_group_id
      t.integer :weight, :default => 0
      t.timestamps
    end
  end
 
 
  def self.down
    drop_table :offer_group_listings
  end
end

With 2.0, it’s even EASIER!

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class CreateOfferGroupListings < ActiveRecord::Migration
  def self.up
    create_table :offer_group_listings do |t|
      t.references :offer, :offer_group
      t.integer :weight, :default => 0
      t.timestamps
    end
  end
  def self.down
    drop_table :offer_group_listings
  end
end
Posted by Jonathan Filed in Ruby on Rails

4 Responses to “Foreign Key Migrations in Rails 2.0”

  1. DuroNo Gravatar Says:
    January 18th, 2008 at 3:04 pm

    Now does this actually create foreign key constraints at the DB level, or the same old software level key enforcement?

  2. JonathanNo Gravatar Says:
    January 21st, 2008 at 12:05 pm

    No it does not.

  3. GeoffNo Gravatar Says:
    February 7th, 2008 at 4:20 pm

    That’s weak. Why is rails so afraid of referential integrity?

  4. Tiago Albineli MottaNo Gravatar Says:
    July 22nd, 2008 at 2:12 pm

    It’s very nice, but it doesn’t work:
    add_column :jogos, :mapa, :references

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