Reattach an object in Hibernate without issuing a SQL statement?

Question

How can I reattach a detached object to a Hibernate Session. The Object has not changed since it was last associated with a (different) Session, so I do not want Hibernate to issue an UPDATE or other SQL statement.

Maybe this will help: http://stackoverflow.com/questions/2730388/hibernate-safely-reattach-an-object-to-the-session — Multisync, Oct 16 '14 at 22:13
@Multisync Thanks. I saw that thread but I didn't see the comment "I think merge() hits the database, which I was hoping to avoid. Note that session.lock(detached_object, LockMode.NONE) does not hit the database at all (if you don't change it after re-attaching it)" ... I will test the lock with LockMode.NONE and report back on what happens. — KyleM, Oct 16 '14 at 22:18
@Multisync Yep, that works. It also works with the newer/not deprecated LockRequest with LockMode.NONE. — KyleM, Oct 16 '14 at 22:24

score 0 · Accepted Answer · answered Oct 16 '14 at 22:23

parent = new Parent();
parent.setName("NewParent");
Session session = util.getSession();
Transaction trans = session.beginTransaction();
LockRequest r = session.buildLockRequest(LockOptions.NONE);
r.lock(detachedChild);
parent.setChild(detachedChild);
session.save(parent);
trans.commit();
session.flush();
session.close();

Reattach an object in Hibernate without issuing a SQL statement?

1 Answers1