Node.hbm.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
	assembly="NHibernate.Test"
	namespace="NHibernate.Test.Operations">

	<class name="Node" polymorphism="explicit">
		<id name="Name">
			<generator class="assigned"/>
		</id>
		<property name="Description"/>
		<many-to-one name="Parent"/>
		<property name="Created" not-null="true"/>
		<set name="Children" inverse="true" cascade="persist,merge,save-update,evict">
			<key column="parent"/>
			<one-to-many class="Node"/>
		</set>
		<set name="CascadingChildren" inverse="false" cascade="persist,merge,save-update,evict,delete">
			<key column="CASC_PARENT"/>
			<one-to-many class="Node"/>
		</set>
	</class>

	<class name="NumberedNode" polymorphism="explicit">
		<id name="Id" unsaved-value="0">
			<generator class="native"/>
		</id>
		<property name="Name">
			<column name="name" index="iname" not-null="true"/>
		</property>
		<property name="Description"/>
		<property name="Created" not-null="true"/>
		<many-to-one name="Parent" class="NumberedNode"/>
		<set name="Children" inverse="true" cascade="persist,merge,save-update" access="field.camelcase">
			<key column="parent"/>
			<one-to-many class="NumberedNode"/>
		</set>
	</class>

</hibernate-mapping>