title: What is a Projection in NHibernate?
body: <p>I have a project where I'm using NHibernate to handle bindings to the database. So far I have mostly been using the basics when it comes to queries. Now I'm struggling with a more difficult query, and I notice new parts of NHibernate. In particular I'm curious about <code>SetProjection</code>, which seems to be important when doing queries.  </p>
  
  <p>What is a Projection, and how will I typically use it? I am assuming that a projection is a general term when it comes to databases, so you are welcome to give more general answers too.. </p>