From: Tau Christiansen Date: 2010-11-10T02:27:48+09:00 Subject: Undefined method I am very new to ROR. (Ruby 1.8.7, rails 2.1.1, rack 0.8.7, mysql 5.1.41) I has my_app/lib/migration_helpers.rb file: module MigrationHelpers def self.foreign_key(from_table, from_column, to_table) constraint_name = "fk_#{from_table}_#{to_table}" execute %{alter table #{from_table} add constraint #{constraint_name} foreign key (#{from_column}) references #{to_table}(id) }.... end In my_app/db/migrate/001_create_dummy.rb: require "migration_helpers" class CreateAirports < ActiveRecord::Migration extend MigrationHelpers def self.up create_table (:airports, :options => "ENGINE=InnoDB") do |t| t.integer :country_id, :null => false #foreign key t.string :code, :null => false, :limit => 3 t.string :name, :null => false, :limit => 45 t.timestamps end foreign_key(:airports, :country_id, :countries) end def self.down drop_table :airports end end When I rake db:migration it got this error: -- create_table(:airports, {:options=>"ENGINE=InnoDB"}) -> 0.0156s -- foreign_key(:airports, :country_id, :countries) rake aborted! undefined method `foreign_key' for # What did I miss? Thank you -- Posted via http://www.ruby-forum.com/.