title: Multiple Rails ORM
body: <p>We have a Rails 3 application with a <strong>PostgreSQL</strong> database (with ~10 tables) mapped by <code>activerecord</code>.  Everything's working fine.</p>
  
  <p>However, we could also like to use:</p>
  
  <ul>
  <li>a <strong>MongoDB</strong> database in order to store images (probably with <code>mongoid</code> gem).</li>
  <li>a <strong>Neo4j</strong> database (probably with <code>neo4j-rails</code> gem) instead of PostgreSQL for some tables.</li>
  </ul>
  
  <p>Using a database with one Rails ORM is simple, thanks to <code>database.yml</code>.  But when there's more than one ORM, how can we process?  Is there a good way to do so?  For instance, ActiveHash (and ActiveYaml) can work well with ActiveRecord.  I think there could be a possibility to let differents ORM working together.  Thanks for any tips.</p>