title: MongoDB Composite Key
body: <p>I'm just getting started with MongoDb and I've noticed that I get a lot of duplicate records for entries that I meant to be unique. I would like to know how to use a composite key for my data and I'm looking for information on how to create them. Lastly, I am using Java to access mongo and morphia as my ORM layer so including those in your answers would be awesome.</p>
  
  <p>Morphia: <a href="http://code.google.com/p/morphia/" rel="noreferrer">http://code.google.com/p/morphia/</a></p>