UnitOfWork / Update / EXCEPTION [TOPLINK-6004]

Question

Hello!
I have an ItemObject which contains ItemLines (ValueHolder, Master-Detail).
I can update the (standard)Item-Objekt attributes, but how can i set the Itemlines-Object? Should i register the Itemlines-ValueHolder in the UnitOfWork? If this is a ValueHolder-Interface, should i read the collection from the database?
I get the following exception:
EXCEPTION [TOPLINK-6004] (TopLink - 9.0.3.2 (Build 429)): oracle.toplink.exceptions.QueryException
EXCEPTION DESCRIPTION: The object [linzag.imds.wdb.bo.model.bean.KnowledgeBranch@50], of class [class linzag.imds.wdb.bo.model.bean.KnowledgeBranch], with identity hashcode (System.identityHashCode()) [80],is not from this UnitOfWork object space, but the parent session's. The object was never registered in this UnitOfWork,but read from the parent session and related to an object registered in the UnitOfWork. Ensure that you are correctly registering your objects. If you are still having problems, you can use the UnitOfWork.validateObjectSpace() method to help debug where the error occurred. For more information, see the manual or FAQ.
regards
Harald.

Answer 1

Harald,
The simplest solution is to read in and register the ItemObject with a UnitOfWork (TX). Then the traversal of the indirect (ValueHolder) relationship will result in the collection of ItemLine objects automatically being registered.
At this point you can add, modify, or remove an ItemLine and the UnitOfWork.commit() will capture the change.
NOTE 1: If you want removal of an ItemLine from the collection to result in its deletion from the database make sure the 1:M relationship is marked as privately owned.
NOTE 2: For collection relationships such as this you do not need to use a ValueHolder for indirection. TopLink also support transparent indirection of collection relationships.
Doug