Foreign Key Migrations in Rails 2.0

January 15, 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
  • It's very nice, but it doesn't work:
    add_column :jogos, :mapa, :references
  • Geoff
    That's weak. Why is rails so afraid of referential integrity?
  • Jonathan
    No it does not.
  • Now does this actually create foreign key constraints at the DB level, or the same old software level key enforcement?
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