How to replicate an object in Hibernate??

sthirunav · **Joined:** Fri Jul 28, 2006 9:52 am **Posts:** 12

I have a parent table for eg: User_Mst is my table and the corresponding POJO object is UserMst.java.

I also have a child table which is User_Addr_Mst and the corresponding POJO object is UserAddrMst.java.

The assocciation between the parent and child is one to many, so Set of UserAddrMst is aggregated with the parent POJO(UserMst).

Now iam fetching a record from User_Mst table using the session.query and iam gettinga the parent object which consist of child set(UserAddrMst).

My requirement is to create another user with the same details as the object with which i have. which means i want to insert a new record with the details of the current object.

How do i do this?

I tried cloning the parent object and tried setting the primary key as null, but it throws me an exception..

Code:

org.jboss.tm.JBossRollbackException: Unable to commit, tx=TransactionImpl:XidImpl[FormatId=257, GlobalId=HP16003273432/46, BranchQual=, localId=46] status=STATUS_NO_TRANSACTION; - nested throwable: (org.hibernate.HibernateException: identifier of an instance of com.myproject.UserMst altered from 4444 to null)

I have the alternate solution as callling an store procedure.. but is it possible with hibernate.. is there any other method to replicate an object..??

Firestarter · **Joined:** Thu Mar 09, 2006 11:52 am **Posts:** 13

When you read an object from the database, it is bound to the session and has the state persistent. You must not set the identifier property of a persistent object to null, cause then the binding to the database row gets messed up.

You have to instantiate a new (transient) object of your type and set all the properties except for the identifier property which you can then make persistent by a call to session.save(yourNewTransientObject).

Hope this helps.

zzyborg · **Posted:** Mon Aug 21, 2006 2:09 am

i back firestarter :) u can have only one single instance of persistant object representing same data inside a session , so changing id of object will result in a complaint from hibernate :) . better u go with a transient object for the new data

ojojoj · **Joined:** Wed Dec 07, 2005 6:31 am **Posts:** 9

Dunno if this helps, but I'm struggling with object replication myself.

I've had some limited success with

Code:

session.evict( myObject ); // detach object from session
myObject.setID( 0 );
session.replicate( myObject, ReplicationMode.OVERWRITE); // rewrite with new id

This produce a new identical row in myObject entity table (except for the new id), but related objects are now related to the new copy. This might be because I'm using annotations and haven't figured out how to cascade "REPLICATE" yet... Anyone know how?

OJ[/code]