流畅的NHibernate:如何告诉它不要映射基类

public abstract class BaseClass
{
    // 基类属性和方法
}

public class SubClassMap : ClassMap<SubClass>
{
    public SubClassMap()
    {
        Id(x => x.Id);
        Map(x => x.Property);
        References(x => x.BaseClass).Not.LazyLoad();
    }
}

    <id name="Id">
       <generator class="native" />
    </id>
   <union-subclass name="SubClass" table="SubClass">
       <property name="Property" />
    </union-subclass>
</class>

public class BaseClassMap : ClassMap<BaseClass>
{
    public BaseClassMap()
    {
        Id(x => x.Id);
        Map(x => x.Property);
    }
}

public class SubClassMap : SubclassMap<SubClass>
{
    public SubClassMap()
    {
        Map(x => x.SubClassProperty);
    }
}