Here is the case:
I know how to map all the children in the parent class using a list or set. But this one has a twist: I want to get only the child matches the last version number in the parent class.

Parent class:
<hibernate-mapping package="com.company.hibernate">
<class mutable="true" name="com.company.hibernate.Node" table="NODE">
<id name="id" column="UUID" type="UuidType">
</id>
<property name="lastVersionNumber" column="LAST_VERSION_NUMBER" not-null="false" type="int">
</property>
<property name="category" column="CATEGORY" not-null="true" type="string">
</property>
<property name="name" column="NAME" not-null="true" type="string">
</property>
?? how to map to get the content object that matches the lastVersionNumber in this class??
</class>
</hibernate-mapping>

Child class:
<hibernate-mapping package="com.company.hibernate">
<class mutable="true" name="com.company.hibernate.Content" table="CONTENT">
<composite-id class="com.company.hibernate.ContentKey" name="key">
<key-property name="id" column="UUID" type="UuidType">
</key-property>
<key-property name="version" column="VERSION" type="int">
</key-property>
</composite-id>
<property name="text" column="TEXT" not-null="false" type="string">
</property>
<many-to-one name="node" class="com.company.hibernate.Node"
lazy="false" insert="false" update="false">
<column name="UUID"/>
</many-to-one>
</class>
</hibernate-mapping>