Generate SQL from your migrations

On one of the projects we're working on, we needed to occassionaly generate SQL from our migrations. Déjà vu, I thought. A few minutes of Googling later, I remembered why: Jay and I had been on a project a couple of years ago whence we had the same need. Jay's code didn't quite work any more due to some ActiveRecord changes, and a search for an alternative implementation turned up nothing.

I took his code and modified it to our needs. A short time later, I had the code pulled out into a rails plugin, migration_sql_generator. Install it (script/plugin install git://github.com/muness/migration_sql_generator.git) and then run the rake task:

rake db:generate:migration_sql

Running this task generates two sql files per migration in db/migration_sql in the form 20090216224354_add_users.sql and 20090216224354_add_users_down.sql.

I've used the plugin with success using the sqlserver adapter, less luck with the mysql adapter (change_column and rename_column blow up because the mysql adapter checks for the presence of a column first) and no luck with the sqlite adapter. Haven't tried it with the postgres adapter.