Hi

From the presentation layer i am sending the partial java object where i am changing only one or two elements (i know the id or key). When i try to do session.merge() on the partial object, my understanding is if there is no persistent instance currently associated with the session, try to load it from the database and merge with the object i am passing.

The object which i am trying to update has both parent and child relations. After the merge i am loosing all the relations and only updating the fields which sets in the java object.

Question is there a way i can update the partial object and preserve all the relations or i have to pass the whole object (with relations) when i do merge. Any inside is of great help.


Regards
Rishi

Rishi,

First of all, read this

http://hibernar.org/articulos_en/persis ... ethods.php

(especially the part that describes what merge() does).

What you are trying to do, is some sort of "code repository style" merge, Hibernate is not designed to do that. How can Hibernate know what properties and/or collection items you want to keep, or to when interpret it as an overwrite?

You will have to resolve that "merging" algorithm yourself, according to your needs, most likely by first retrieving the current object, and then comparing it with the new information you want to persist.