Reloading object from DB without overwriting Hibernate cache

fox_mttraa@trashmail.net · **Joined:** Mon Aug 25, 2008 10:07 pm **Posts:** 1

Dear Hibernate experts.

I have the following problem.

My method A needs to check the persistent object O (instance O1) and see if it has changed since it was last persisted in the DB.
In order to do that A needs to reload a "fresh" version of O (instance O2 of the same object) and compare it with O1.

However if I use the Session.Refresh(), O1 gets reinitialized with the same values as O2 and I cannot compare the 2 objects anymore.
And if I use Session.Get(), then O2 will be the same as O1 because Hibernate will use the cached version of O.

Is there any way to reload O from the DB without overwriting the cache (i.e. O1) ?

I guess a solution would be to load O2 in a another session but that sounds pretty heavy for this simple problem.

Any suggestion would be greatly appreciated.

Thank you.

Clement

frag · **Joined:** Sun Aug 31, 2008 9:22 pm **Posts:** 2

Hi Clement,

You can use a criteria to obtain an object from the database.
You can write something like that :

Code:

dim O2 as YourObjectType
Using session As ISession = _SessionFactory.OpenSession()
    Dim c As ICriteria = session.CreateCriteria(GetType(YourObjectType)) _
                    .Add(Expression.Eq("PropertyX", O1.PropertyX)) _
                    .Add(Expression.Eq("PropertyY", O1.PropertyY)) _
                    .SetMaxResults(1)
    O2 = c.UniqueResult(Of YourObjectType)()
End Using

Hope this will help you.