title: How to quickly query multiple collections in Mongoid?
body: <p>Foo, Bar and Baz are all Mongoid collection models. There are the only collections in the DB.</p>
  
  <p>Is there a more efficient way to get all the data in the DB?</p>
  
  <pre><code>Foo.all + Bar.all + Baz.all
  </code></pre>