Hibernate Table-Per-Subclass (not related to ZK question)

<hibernate-mapping>
   <class name="com.javalobby.tnt.hib.User" table="USER" lazy="false">
      <id name="id" type="long" column="ID">
         <generator class="identity" />
      </id>

      <discriminator column="type" type="string"/>
      
      <property name="firstName" column="first_name"/>
      <property name="lastName" column="last_name"/>
      
      <subclass name="com.javalobby.tnt.hib.Employee" discriminator-value="employee">
         <join table="employee">
            <key column="id"/>
            <property name="jobTitle" column="job_title"/>
            <many-to-one name="supervisor" column="supervisor_id" not-null="true" />
         </join>
      </subclass>
   </class>
</hibernate-mapping>