Hibernate version: 2.1.7

Mapping documents:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 2.0//EN" "hibernate-mapping-2.0.dtd">

<hibernate-mapping>

<class name="com.test.oneToOne.OneToOneParent" table="one_to_one_parent">
<id name="pk" column="pk" type="java.lang.Long">
<generator class="sequence">
<param name="sequence">hibernate_sequence</param>
</generator>
</id>
<property name="comment" column="comment" type="java.lang.String"/>
<one-to-one
name="child"
property-ref="parent"
cascade="all"
class="com.test.oneToOne.OneToOneChild"
constrained="false"/>
</class>

<class name="com.test.oneToOne.OneToOneChild" table="one_to_one_child">
<id name="pk" column="pk" type="java.lang.Long">
<generator class="sequence">
<param name="sequence">hibernate_sequence</param>
</generator>
</id>
<many-to-one
name="parent"
class="com.test.oneToOne.OneToOneParent"
column="fk_parent"
cascade="save-update"/>
</class>
</hibernate-mapping>


Code between sessionFactory.openSession() and session.close():
tx = hibernateSession.beginTransaction();
hibernateSession.saveOrUpdate(bean);
tx.commit();


The generated SQL (show_sql=true):update one_to_one_parent set comment=? where pk=?

Code Parent:
public class OneToOneParent extends HBBean{
private String comment;
private OneToOneChild child;

public String getComment() {
return comment;
}

public void setComment(String comment) {
this.comment = comment;
}

public OneToOneChild getChild() {
return child;
}

public void setChild(OneToOneChild child) {
if(child != null){
child.setParent(this);
}
this.child = child;
}
}

Code Child:
public class OneToOneChild extends HBBean{
private OneToOneParent parent;

public OneToOneParent getParent() {
return parent;
}

public void setParent(OneToOneParent parent) {
this.parent = parent;
}
}


I want to delete child (OneToOneChild) in parent (OneToOneParent). I set null to a parent's property: child
but it is not deleted :-( Is there a way to?

I've searched all documents and forum but couldn't find :-(

pls, help me. Any help is welcome.