Hi,

I'm implementing a DAO method to retrieve the next id in a column using pessimistic blocking, so I'm sure that anyone else uses the same number (what would derivate in a primary key violation).

My code is:

Integer maximo = null;
Query query = session
.createQuery(
"select max(padre.bloqueo)+1 from PadreVO padre")
.setLockMode("padre", LockMode.UPGRADE_NOWAIT);

while (true)
{
try
{
maximo = (Integer) query.uniqueResult();

break;
}
catch (HibernateOptimisticLockingFailureException e)
{
}
}

return maximo;

But I'm getting this exception:

java.lang.IllegalArgumentException: alias not found: padre

If I don't specify the select clause to my HSQL query, then it works great, but obviously don't get the desired result.

Any ideas?

It makes zero sense to acquire an UPGRADE lock on a projected entity. You only use upgrade locks for things you are going to update.

I see, but how can I accomplish the objective I'm trying to achieve?