# <class name="Parent">   
# <id name="id">   
# <generator class="sequence"/>   
# </id>   
# <property name="name" column="name"/>   
# <set name="boyChildren" table="child">   
# <composite-key>   
# <property column="parent_id"/>   
# <property column="gender" value"male"/>   
# <composite-key>   
# <one-to-many class="Child" column="id"/>   
# </set>   
# <set name="babyChildren" table="child">   
# <composite-key>   
# <property column="parent_id"/>   
# <property column="gender"/ value="female">   
# </composite-key>   
# <one-to-many class="Child" column="id"/>   
# </set>   
# </class>