Hi,

If I try to update an object loaded in the same session, by calling one of the setter and then flush(), if the new value of the property is the same like the old one, no update is issued to the DB.

Session session = ...
Person person = session.find(...)
person.setName("sameName") // same value as in the person object
session.flush();
session.close();

On the other hand, if I load Person in a previous session and try to update in a new one, an update is issued to the DB even if nothing changes in the object's fields

Session session = ...
Person person = session.find(...)
session.close();

Session session1 = ...
person.setName("sameName") // same value as in the person object
session1.update(); // or saveOrUpdate()
session1.flush();
session1.close();

Why is that? Can I achieve the same functionality as in the first case?

Thanks,

--steve

In Hibernate 2.1, you may enable select-before-update, which means that Hibernate will grab a snapshot from the database, and decide if it really needs to update the row. Otherwise, Hibernate has no snapshot when update() is used, so it must send an update. Also in 2.1, you can reassociate the object with the session using lock(), which does NOT force an update.

Thanks Gavin.

--steve