Hi,

I desperately need help. I couldn't work out a simple example of hibernate .

I am using oracle as a database. Here is my hbm.xml file

<hibernate-mapping>
<class name="events.Event" table="EVENTS">
<id name="id" column="EVENT_ID" type="integer" unsaved-value="0">
<generator class="increment"/>
</id>
<property name="dt" type="timestamp" column="EVENT_DATE"/>
<property name="title" column="TITLE"/>
</class>
</hibernate-mapping>


the class file doing transactions :

/*
* EventManager.java
*
* Created on 12 January 2006, 10:33
*/

package events;

import org.hibernate.Session;

import java.util.Date;
import java.util.List;
import util.HibernateUtil;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;


public class EventManager {
private static Log log = LogFactory.getLog(HibernateUtil.class);
public static void main(String[] args) {

EventManager mgr = new EventManager();
long id = 101;
Event eve = new Event();
System.out.println("INSIDE LIST... ");
if (args[0].equals("store")) {

mgr.createAndStoreEvent("My Event", new Date());
}
else if (args[0].equals("list")) {
List events = mgr.listEvents();
for (int i = 0; i < events.size(); i++) {
Event theEvent = (Event) events.get(i);
System.out.println("Event: " + theEvent.getTitle() +
" Time: " + theEvent.getDt());
}
}
HibernateUtil.getSessionFactory().close();
}

private void createAndStoreEvent(String title, Date theDate) {
try {
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();

Event theEvent = new Event();

theEvent.setTitle(title);
theEvent.setDt(theDate);

session.save(theEvent);
session.update(theEvent);
System.out.println("event id : "+theEvent.getId());
System.out.println("event title : "+theEvent.getTitle());
session.getTransaction().commit();
session.connection().commit();

//session.connection().createStatement().execute("SHUTDOWN");
}catch(Exception e){}
}


private List listEvents() {

Session session = HibernateUtil.getSessionFactory().getCurrentSession();

session.beginTransaction();

List result = session.createQuery("from Event").list();

session.getTransaction().commit();

return result;
}

}

I am not getting any exceptions. But the values not been stored into the table. Please help me with it. Anybody have an idea ?

Thanks,
JSV.

You aren't doing anything in your catch statement. Are you sure you aren't getting an error?

I had this one, once before in a application I took over. It was very funny to find out the problem.

Never catch all exceptions without outputting the message!!!

Regards Sebastian

Yes you are right. I printed the exception. I got the exception :

identifier of an instance of events.Event was altered from 1 to 1

I couldn't find out why this exception happens. Please help me...


Thanks,

you cannot change the primary key of an object. Hibernate identifies the objects in the session by the primary key.
If you could change this, you would pull the rug out from under Hibernate.

Regards Sebastian

I solved the problem. I noticed that i have given mistakenly the type of primary key . Instead of long, I gave integer.

Now its working fine.

Thanks Sebastian for your replies and suggestions.