How can I add an auto generated ID to an existing table?

Question

I have a table in my schema that does not have an auto generated ID primary key because I deactivated that option when creating it. Is there a way to put a new column ID that is auto incremented in my table?

Answer 1

if you don't want to Add new migration, also if there is not much more data which is most useful, than rails Also provide functionality to DOWN Migration.

rake db:migrate:down VERSION=20190204205537

'20190204205537' this should be your migration version

it will 'DOWN' your migration, than you can edit it, i mean remove the PRIMARY KEY false. and simply run

rake db:migrate

I Hope this may help to you. Thank you.

Answer 2

Yes, generate a migration with primary_key:

rails g migration add_id_to_my_tables id:primary_key

That will produce a change with add_column:

def change
  add_column :my_tables, :id, :primary_key
end