persistence@glassfish.java.net

JPA and merging

From: bea <beaotx_at_gmail.com>
Date: Wed, 2 Sep 2009 16:39:41 +0200

Hi,

I'm using JPA (version 1.0.2) in order to manage some entities.
Right now I've one entity called Operator with an attribute called Contacts,
that is a relation-ship one-to-many to other table, with a cascade type ALL.

Some times I update the Operator and the nested Contacts with the merge
method. I've two questions:

1. Is there any way to delete or add a nested contact in the update
operation? ie, I update some date of the operator with a merge and at the
same time I wanto to delete one of its contacts.

2. If I've an entity of the database persisted, and I've a new entity with
the same ID than the one persisted but some data modified, could I merge the
second entity with the first one with a simple merge method? If I do that
all the old data not represented in the new entity is removed.



Thanks