activerecord - Create missing auto increment attribute with rails migration

Question

I'm writing a migration to convert a non-rails app into the right format for rails - one of the tables for some reason does not have auto increment set on the id column. Is there a quick way to turn it on while in a migration, maybe with change_column or something?

Answer 1

You need to execute an SQL statement.

statement = "ALTER TABLE `users` CHANGE `id` `id` SMALLINT( 5 ) UNSIGNED NOT NULL AUTO_INCREMENT"
ActiveRecord::Base.connection.execute(statement)

Note this is just an example. The final SQL statement syntax depends on the database.