Hi,
I encounter some trouble using Hibernate.
I use a table "User" and I have 2 access in parallel (using Web Services) on the same entry in my musql DB table.
Each method is useed to modify a different field (data1 and data2) in my entry.
I have the following :
Methode1
User user = get(user);
try {
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();

user.setData1(data1);

session.update(user);

transaction.commit();
session.close();

} catch (HibernateException e) {
e.printStackTrace();
}

Methode2
User user = get(user);
try {
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();

user.setData2(data2);

session.update(user);

transaction.commit();
session.close();

} catch (HibernateException e) {
e.printStackTrace();
}

The matter is that my 2 accesses occur at the same time and my objects "User" are not synchronized. An atomicity problem.
My 2 processes call the getUser method first (query select on my DB) at the same time. Then if the data1 is modified by the first process, this modification isn't taken into account and is lost by the second process during the data2 processing.
What can be done ?

Two other questions :
- How can I confgure Hibernate to update only the field (or the colonn) I have modified in my entry ?

- How can I perform an update request like that :
String hqlUpdate = "update User u set u.data1 = :mydata1 where u.name = :name";
int updatedEntities = s.createQuery( hqlUpdate )
.setString( "name", name )
.setString( "mydata1", mydata1 )
.executeUpdate();
tx.commit();
session.close();
I found 1 entity but it doesn't commit the data.

Thanks.

An idea ?

Try enabling dynamic-update and using "dirty" optimistic locking:

Hibernate will only update fields that have changed. Be aware that when the _same_ field is changed by both threads hibernate will throw a StaleObjectStateException on one.

I tried your update code, it works perfectly for me.

Hi,
>> Each method is useed to modify a different field (data1 and data2) in my entry.

Since we update different columns from 2 sessions, we need to use
<optimistic-lock="all">

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Ok, thanks.
It stills doesn't work.

1. I use an hibernate.cfg.xml file.
My database has already been created without the optimistic-lock option and populated... so my question is the following : will the <property name="hibernate.hbm2ddl.auto">update</property> property allows to configure the dynamic-update="true" optimistic-lock="dirty" options or must I use a <property name="hibernate.hbm2ddl.auto">update</property> to do so ?
I tried these options in my dev environment using HSQL but it doesn't work with "dirty" and "all".
An idea ?
I need to try it with mysql and oracle.

2. Have you an idea why the following doesn't work :
String hqlUpdate = "update User u set u.data1 = :mydata1 where u.name = :name";
How can I make an update SQL request ?

3. Last question, I tried to use a session.lock(user, LockMode.UPGRADE) that doesn't work too. Can it be linked to the fact that I change the session for each request ?

Thanks a lot.