title: NHibernate base and derived class mapping
body: <p>Situation:
  I have a class <strong>MyClass</strong> and its "lightweight" version <strong>MyClassLite</strong>, so i have</p>
  
  <pre><code>public class MyClass : MyClassLite
  </code></pre>
  
  <p>I also use <strong>hbm</strong> file for mapping my classes (they are mapped to the same table).
  The thing is that when i try to get a list of <strong>MyClassLite</strong> entities, i get not only <strong>MyClassLite</strong> entities, but a list of <strong>MyClass</strong> entities moreover. How can i rid of that?</p>