simulating select for update in hibernate.

[Chase Bonham]

I have a POJO mapped to a table (one primary key) and everytime I do an update to a row of that table I want to do a "select for update" effectively locking
other people from concurrently making the update. Is there a hibernate 2.0
mapping attribute I can use?

[Ghulam Rashid]

Probably you have use LockMode feature of Hibernate.


Transaction transaction = session.beginTransaction();
Country country =
(Country) session.get(Country.class, id, LockMode.UPGRADE);
cat.setName("India");
transaction.commit();

Country will be loaded into session using a SELECT FOR UPDATE,
thus locking the retrieved rows in the database until they�re released when the transaction ends.

Hope this will help.

Rashid

[Ghulam Rashid]

correction to above code.
country.setName("India");

[Kent Bull]

I know this is a bump. However, this post came up for me in a google search for Hibernate transaction locking so here is the updated solution I found:

class TransactionSequenceService implements ITransactionSequenceService {
        private TransactionSequence transactionSequence; // this is populated by

        //.... other methods to initialize service and populate transactionSequence;

        public Integer getNextTransactionNumber() {
          Integer newTransactionNumber;
          Session session = sessionFactory.openSession();
          Transaction transaction = session.beginTransaction();
          try {
  
              TransactionSequence _transactionSequence =
                      (TransactionSequence) session.get(TransactionSequence.class, new Integer(transactionSequence.getId()), new LockOptions(LockMode.READ));
              _transactionSequence.setLastTransactionNo(_transactionSequence.getLastTransactionNo() + 1);
              newTransactionNumber = _transactionSequence.getLastTransactionNo();
              session.flush();
              transaction.commit();
          } catch(Exception e) {
              logger.error("Could not set and get the latest transaction number!");
              throw new RuntimeException("Problem getting next transaction number");
          } finally {
              session.close();
          }  
          return newTransactionNumber;
    }
}