How do I add migration with multiple references to the same model in one table? Ruby/Rails
You can do this simply with the add_column
method in your migrations and set up the proper associations in your classes:
class AddFields < ActiveRecord::Migration def change add_column :tickets, :image_1_id, :integer add_column :tickets, :image_2_id, :integer endendclass Ticket < ActiveRecord::Base belongs_to :image_1, :class_name => "Image" belongs_to :image_2, :class_name => "Image"endclass Image < ActiveRecord::Base has_many :primary_tickets, :class_name => "Ticket", :foreign_key => "image_1_id" has_many :secondary_tickets, :class_name => "Ticket", :foreign_key => "image_2_id"end
This blog post, Creating Multiple Associations with the Same Table, goes into more detail.
In Rails 5.1 or greater you can do it like this:
Migration
class AddFields < ActiveRecord::Migration def change change_table(:tickets) do |t| t.references :image1, foreign_key: { to_table: 'images' } t.references :image2, foreign_key: { to_table: 'images' } end endend
This will create the fields image1_id
, and image2_id
and make the database level references to the images
table
Models
as in rossta's asnwer
class Ticket < ActiveRecord::Base belongs_to :image_1, class_name: "Image" belongs_to :image_2, class_name: "Image"endclass Image < ActiveRecord::Base has_many :primary_tickets, class_name: "Ticket", foreign_key: "image_1_id" has_many :secondary_tickets, class_name: "Ticket", foreign_key: "image_2_id"end
FactoryBot
If you uses FactoryBot then your factory might look something like this:
FactoryBot.define do factory :ticket do association :image1, factory: :image association :image2, factory: :image endend