delete old child set before insert new child set

JavaJason · **Joined:** Thu Jul 22, 2004 4:32 am **Posts:** 31

parentPO.setChildSet(childSet);
I want to delete old child set from database before insert new child set

What should I do?

ParentPO.hbm.xml

Code:

        <set name="childSet" lazy="true" inverse="true" cascade="all">
            <key column="parentId"/>
            <one-to-many class="ParentPO"/>
        </set>

ChildPO.hbm.xml

Code:

        <many-to-one name="parentPO" class="ParentPO">
                 <column name="parentId" />
        </many-to-one>

Any suggestion would be appriciated.

JavaJason · **Joined:** Thu Jul 22, 2004 4:32 am **Posts:** 31

When I set ParentPO.hbm.xml like this:
<set name="userSet" lazy="true" inverse="true" cascade="all-delete-orphan">
a error occurs:
net.sf.hibernate.HibernateException: You may not dereference a collection with cascade="all-delete-orphan"
at net.sf.hibernate.impl.SessionImpl.updateUnreachableCollection(SessionImpl.java:2915)
at net.sf.hibernate.impl.SessionImpl.flushCollections(SessionImpl.java:2784)
at net.sf.hibernate.impl.SessionImpl.flushEverything(SessionImpl.java:2257)
at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2235)

ernst_pluess · **Posted:** Thu Sep 02, 2004 2:30 am

My guess is, that your replacing the Set. Instead clear it and then fill the new entries into the empty one.

HTH
Ernst

JavaJason · **Joined:** Thu Jul 22, 2004 4:32 am **Posts:** 31

ernst_pluess,Thanks for you reply.
But this still did not work.

ernst_pluess · **Posted:** Thu Sep 02, 2004 6:11 am

Please show the Java code between sessionFactory.openSession() and session.close().
The red box! you know?

Ernst

JavaJason · **Joined:** Thu Jul 22, 2004 4:32 am **Posts:** 31

parentPO = session.load(ParentPO.class,"p001");
childPO1.setParentPO(parentPO);
childPO2.setParentPO(parentPO);
HashSet set = new HashSet();
set.add(childPO1);
set.add(childPO2);

parentPO.setChildSet(set);

I want hibernate to delete old child set before insert,but it doesn't work correctly,It will insert two child po into database directly

anthony · **Posted:** Thu Sep 02, 2004 7:35 am

you should have 2 methods (addChild() & removeChild()) to have a secure object graph when working on your collection.

Anyway, change

Code:

HashSet set = new HashSet(); 
set.add(childPO1); 
set.add(childPO2); 

parentPO.setChildSet(set); 

to

Code:

parentPO.getChildSet().add(childPO1); 
parentPO.getChildSet().add(childPO2); 

oh, and if you want to remove all childs, just call parentPO.getChildSet().removeAll(); (but don't forget, for each child, to call theChild.setParent(null).

JavaJason · **Joined:** Thu Jul 22, 2004 4:32 am **Posts:** 31

Thanks a million.