Transitioning from one database to another, or even to a whole new database with a new adapter, can be tough. Here's an easy way to transition content.
For whatever reason, you might just need to transition your Rails app's content from one database type to another (or even just to a new database with the same adapter). I've found that yaml_db does a great job helping you with this task.
The first thing to do is get
$ bundle install
To dump the data, just run the appropriate rake task.
$ bundle exec rake db:data:dump
Then, switch your database over to the new database. Note: If you're switching adapters, make sure you have the appropriate gem(s) installed.
You'll need to make sure your database is setup. If it isn't, then get on it!
$ bundle exec rake db:create $ bundle exec rake db:migrate
And then you can bring the data into the new database.
$ bundle exec rake db:data:load
Nice and easy! Be sure to note that if you're doing this to move content, then you may need to go through additional steps to move any uploaded assets.
Here are a couple methods for dealing with uni-directional many-to-many associations in Rails.