title: How to map a self-reference in NHibernate
body: <p>I have a very special NHibernate mapping case. The class has a reference to itself.</p>
  
  <pre><code>public class MyClass
  {
     public Guid Id { get; set; }
     public MyClass SelfReference { get; set; }
  }
  </code></pre>
  
  <p>The data base table has a foreign key field on the primary key of the same table. And event worse, this self reference can be null.</p>
  
  <p>Is that possible to map and how can this be done?</p>