Hi ,

I am using Hibernate 3 and have a small query regarding hibernate session.

If suppose I have an Object called 'Order' containing 'Buyer' and 'Seller' references like



when I try to save order object like session.save(order) it will try to persist the Buyer and Seller details in their respective tables. Now while trying to persist Order if after saving the buyer details, and error comes up while trying to save the Seller details, would the Buyer details be also reverted back or do I have to use session.beginTransaction() in order to ensure atomicity before doing session.save(order);


Thanks ,
Ashish Abrol

Hi,

When calling session.save(order), the values are inserted but not commited.
So rollback the transaction if you get an error.
tx.rollback();

If you don't get any errors then tx.commit()

Thanks for the prompt reply but what I wanted to ask was that just using session.save would do that or do I have to use session.beginTransaction() method.

I agree with what you said that the values are inserted but not commited when we do session.save(order) but if there is any error then Hibernate would do that on its own or do we have to use transaction alongwith that.

I have many methods where I am only using session.save with using transactions. What I need to know is that while saving the order object if there is any error while saving any of the references will Hiberante revert back if I am not using transactions.

Hi,

Do look into the session methods.

http://www.hibernate.org/hib_docs/v3/ap ... ssion.html

I dont see any rollback in the session. we flush the session to save.

Possibly will investige and then let you know.

I think I failed to explain my problem properly. I'll try to do that again.

These are the steps-

1)Session s = HibernateUtil.currentSession();
2)s.save(order);

At this stage Buyer gets inserted but while trying to insert Seller there is some error. So it is obvious that Seller would not be inserted in the Seller table.

Now will the Buyer details that have already been inserted, would those details be also deleted or revert back.

Remember that I am NOT USING TRANSACTIONS anywhere in the above example. ie. There is no s.beginTransaction(); or rollback code above.

Every operation done with a session has an implicit transaction associated (even if you didn't create one yourself).

From the Session API Documentation (http://www.hibernate.org/hib_docs/v3/ap ... ssion.html):

"If the Session throws an exception, the transaction must be rolled back and the session discarded. The internal state of the Session might not be consistent with the database after the exception occurs."

From that phrase, I understand that you should call Session.getTransaction().rollback(), because your Session might have wrong data in it.

Hope it helps.

Pd: and answering your question, the buyer details should be still in the session, in spite of the exception.

You should have some kind of transaction management strategy in place.

Whether you do it programmatically or have some infrastructure (JTA-type setup) do it for you, you should plan out what you *want* to happen.

For example, doing it programmatically, if you want the entire operation to be atomic, then do this:

1)Session s = HibernateUtil.currentSession();
2)Transaction tx = s.beginTransaction();
3)s.save(order);
4)tx.commit();

If you get an error on line (3) then do a tx.rollback().

Now you don't have to ask anyone or wonder what Hibernate is doing.