ruby on rails - 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(: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

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.