CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-3activerecord
alf
alf

Reputation: 18540

Add Id column in a migration

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(:the_model, :id => false) do |t|
  # columns
end

Now, on a new migration, I want to add the id column in a Rails standard way (not using database specific sql). How can I do that?

I already tried this without success:

change_table(:the_model, :id => true) do |t|
end

Upvotes: 23

Views: 25330

Answers (3)

cdesrosiers
cdesrosiers

Reputation: 8892

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.

Upvotes: 49

Prabhat Thapa
Prabhat Thapa

Reputation: 81

You don't need to mention :integer

rails g migration add_id_to_model id:primary_key worked for me.

Upvotes: 8

Samiron
Samiron

Reputation: 5317

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.

Upvotes: 4

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