How to add foreign key in rails migration with different table name

Question

How can I assign different table name with adding foreign key. for e.g

I have a model like

class MyPost < ActiveRecord::Base
  has_many :comments, cla         


        

Answer 1

You can pass in options for the foreign key as following:

class CreatePostComments < ActiveRecord::Migration
  def change
    create_table :post_comments do |t|
      t.references :post, foreign_key: { to_table: :my_posts }, index: true
      t.timestamps null: false
    end
  end
end

This is also true for the index option if you like to add a unique constraint:

t.references :post, foreign_key: { to_table: :my_posts }, index: { unique: true}

By the way, references is an alias for belongs_to, or to be more exact, belongs_to is an alias for references.

See the details in the implementation rails 5.0.rc2 & rails 4.2