Foreign Key Migrations in Rails 2.0

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

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!

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

This entry was posted on Tuesday, January 15th, 2008 at 4:51 pm and is filed under ruby on rails. You can follow any comments to this entry through the RSS 2.0 feed. You can leave a comment, or trackback from your own site.

9 comments

  1. Duro
    January 18, 2008 at 11:04 pm

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

  2. Duro
    January 18, 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?

  3. Jonathan
    January 21, 2008 at 8:05 pm

    No it does not.

  4. Jonathan
    January 21, 2008 at 12:05 pm

    No it does not.

  5. Geoff
    February 8, 2008 at 12:20 am

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

  6. Geoff
    February 7, 2008 at 4:20 pm

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

  7. Tiago Albineli Motta
    July 22, 2008 at 10:12 pm

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

  8. Tiago Albineli Motta
    July 22, 2008 at 2:12 pm

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

  9. John Doe
    April 1, 2010 at 7:03 am

    MySQL doesn't respect foreign key. So I think it's the reason why those constraints are not automaticly created. (MySQL sucks!)

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