如何在没有数据库持久性的情况下让NHibernate知道一流的“Null对象”？

I would like to make use of the Null Object pattern in my domain, but I don't want to have records in my database that relate to it - I would prefer it if NHibernate were able to map a SQL null value to my Null object, and vice versa.I would like to make use of the Null Object pat