Add Id column in a migration

Question

I have a Rails app, where one of the models does not have the id column. Doing some research I found the migration that created it:

create_table         


        

Answer 1

You can either manually add the id column:

add_column :table_name, :id, :primary_key

or clear (or backup) your data, rollback to this migration, get rid of the option :id => false, and re-migrate.

Answer 2

You already got your answer, but here is a one liner that does all in this case

rails generate migration AddIdToModel id:integer

Look at the syntax of migration file name AddColumnNameToTableName followed the column description. It will generate something like below

class AddIdToModel < ActiveRecord::Migration
  def change
    add_column :models, :id, :integer
  end
end

Now you can change this line if you feel for anything else. and just run rake db:migrate.

Answer 3

You don't need to mention :integer

rails g migration add_id_to_model id:primary_key worked for me.