Hi,

I ran across a problem and tried different solutions without any luck. I dont think there's a bug in hibernate but probably a lack of similar kind of example and my understanding of hibernate, I am not able to sovle it yet.

So, now I am trying to figure out how other people are solving this problem as I BELIEVE this is a common use-case.

1. User loads a parent object with children collection in a session.
2. User updates the parent object and adds/removes/updates some children and pass them on for update.

* Due to the disconnected nature of the application, we dont keep the children ids as these are meaningless for the user (and GUI).
* We want to avoid finding out new/modified/delete children and hence want to throw away existing children and save new ones and update the parent object.

I've gone through all FAQs and hibernate javadocs without any luck.

Can somebody please guide me to an example of above update use-case.

Thanks,
Tahir

I mistyped when I wrote javadocs.......actually I've printed and read the complete manual (PDF) and could not find an example of one-shot-delete in my scenario.

I tried various solutions but nothing has worked so far. Should I start posting exceptions/warnings in each of those cases?

Tahir

It looks like you are a bit confused. one shot delete does not apply to parent/child relationships. It is mainly of value for many-to-many associations and collections of values.

Dereferencing a collection of entities does NOT delete them. This should be quite clear from the documentation.

Gavin: Thanks for your reply. Can you point me to some open-source example to learn using parent/child with hibernate.


No doubt, I am confused. I "now" have the following line working that removes the existing children from the DB during the update.
voyage.getVoyagePorts().clear();


For Add-New, I had code that used to work with hibernate 1.x and stopped working in 2.x till I changed to following.

try {
tx = session.beginTransaction();
session.save(voyage);
session.flush();

// previously only voyage.setVoyageCrew(crewData); was required and the children collection was saved. But now, I have to do the following.

for (int i=0; i<crewData.size(); i++) {
VoyageCrew vc = (VoyageCrew) crewData.get(i);
vc.setVoyage(voyage);
session.save(vc);
}
tx.commit();
} catch (HibernateException e) {
if (null != tx)
tx.rollback();
log.error("Error in addVoyage",e);
throw e;
} finally {
session.close();
}

Now, I am fine as my code is working now but it would be nice to know exactly how Hibernate expect me to write addNew and update methods.

Tahir

http://www.hibernate.org/159.html
http://www.hibernate.org/78.html

You'll probably find what you want.