We have two objects that have a rather complex relationship. One is the User object, the other is called a Proof. The proof has a many to one relationship with the User as a field called creator. The user has two sets of proofs. One is proofs that the user created (a one-to-many relation), and the other is proofs that the user can see (a many-to-many relation). The problem is that with the many-to-many relationship, nothing gets persisted. If I add a proof to the user's pendingProofs set, it won't stay there. No row is created in the pendingProofz table. If I check the User object for the existence of the proof in the pendingProof set after adding it, it appears to be there, but the change isn't persisted at all. The table structure seems correct. I can't figure this out at all.

Here are the relevant parts to the mapping docs:

User.hbm.xml:
<set name="proofs" cascade="all" inverse="true" lazy="true">
<key column="creator_id" />
<one-to-many class="mc.Proof"/>
</set>

<set name="pendingProofs" lazy="true" table="pendingProofz">
<key column="user_id" />
<many-to-many class="mc.Proof" column="proof_id"/>
</set>


Proof.hbm.xml:
<many-to-one name="creator" class="md.user.User" column="creator_id" />


I apologize if I didn't explain this well, include enough information, or missed a pertinent part in the documentation. I will provide any more info and will gladly read through relevant parts of the documentation.

1. I would add cascade="save-update" to the <set>.
2. Didn't you forget to commit transaction ?

Show code which inserts proof into set and log Hibernate generates.

I added the cascade to the many-to-many set.

The code I use to insert the proof into the set is as follows:

User user = (User)getSession().load(md.user.User.class, (Long) iterator.next());
getProof().getLatestVersion().getUsers().add(user);
user.getPendingProofs().add(getProof());
commitContinue();


When I do that now, I get a TransientObjectException:
The following error has been reported:

java.lang.Exception: net.sf.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: md.user.User


We use a custom set of classes to take care of commits and db connections. The three classes we use are HibernateMonitor (a tapestry extension of sorts), HibernateEngine, and HibernateSessionSource. You can see the source for them here:
http://thechrisproject.com/prog/

Thanks for your reply!

Errr... do you have <set> from Proof to User??? Your mapping does not reflect this.

No, Proofs contain Versions, which contain sets of users. If you think that is relevant, I will post the mapping docs for the Version as well.

Does all of this happens within single session or you are loading some objects in one session and use them in another?

The proof is loaded in a different session and then set on this page before it is activated. The User is loaded in the session that is got at the beginning of the code I posted.

I thimk it is the problem...

http://forum.hibernate.org/viewtopic.ph ... eassociate

I think that was it. Someone else solved the problem by just passing the Proof's id to the page and reloading it there, which I guess assures that it is all done in the same session. Thanks for your help.