Update: Todd Huss has created a github project based on this – probably worth a look. You can find it here
Currently working on a merb project using datamapper – nice framework, but the auto-migrate feature is fairly limited – So I decided to hook up ActiveRecord’s migrations into the app. This code could be equally as easily adapted in to anything else.
First, I created a folder for the migrations to live in:
mkdir -p db/ar_migrationsI then appended a few tasks ripped out of Rails and slightly tweaked to the Rakefile:
These will read from database.yml in config/ , so make sure you’ve got datamapper set up.
Lastly, Let’s create an example migration to create the datamapper sessions table in db/ar_migrations/001_create_dm_session_table.rb:
Once this is done, you can run rake db:migrate , and the DB will get the sessions table added. The db:schema:load task is also there, so you should use this when you first deploy your app to a new server. The naming is also consistent with rails, so capistrano should interact with it out of the box, with the exception that the environment to load/migrate needs to be called MERB_ENV instead of RAILS_ENV
When creating additional migrations you will need to follow the ‘proper’ naming scheme: the filename should start with an incrementing three digit number, and the rest should be a ‘flattened’ version of the class name. (i.e migration class AddPostTable becomes add_post_table).