Hello Friends I am new to hibernate I have taken this example from hibernate quickely, I am using oracle 10 g. I have a problem when I run the EventLoader It inserts the values into database but the values inserted into to the database are unpredictab.

Explanation of problem is as follows:
there are two tables
1. Events
2. Locations

Event contains an uid field which is pk.
and Location contains an iid field which is pk

when I insert the values using the hibernate it inserts values into database as
for first insert row uid=1 and iid=2
for second insert row uid=3, and iid=4 and so on

but when I used the mysql this is working fine
what is problem with oracle

the following is the source code.

Location Class
import java.io.Serializable;
public class Location implements Serializable
{
private Long id;
private String name;
private String address;

public void setId(Long id){
this.id = id;
}

public void setName(String name){
this.name = name;
}

public void setAddress(String address){
this.address = address;
}

public Long getId(){
return this.id;
}

public String getName(){
return this.name;
}

public String getAddress(){
return this.address;
}
}

event Class

package com.manning.hq.ch01;

import java.io.Serializable;
import java.util.Date;

public class Event implements Serializable
{
private Long id;
private int duration;
private String name;
private Date startDate;
private Location location;

public Long getId(){
return this.id;
}

public void setId(Long id){
this.id = id;
}

public int getDuration(){
return this.duration;
}

public void setDuration(int duration){
this.duration = duration;
}

public String getName(){
return this.name;
}

public void setName(String name){
this.name = name;
}

public Date getStartDate(){
return this.startDate;
}

public void setStartDate(Date startDate){
this.startDate = startDate;
}

public Location getLocation(){
return this.location;
}

public void setLocation(Location location){
this.location = location;
}
}


EventLoader Class

import org.hibernate.*;
import org.hibernate.cfg.Configuration;
import java.util.*;
import com.manning.hq.ch01.Location;

public class EventLoader
{
public static void main(String[] args)
{
Location location = new Location();

location.setName("Nitin N Kalaskar");
location.setAddress("At post Nagapur dist beed");

Event event = new Event();

event.setName("Annual Meeting");
event.setDuration(60);
event.setStartDate(createDate(2008,2,7));
event.setLocation(location);

Session session = null;
Transaction tx = null;
SessionFactory sessionFactory = null;
try
{
Configuration configuration = new Configuration();
configuration.configure();

sessionFactory = configuration.buildSessionFactory();
session = sessionFactory.openSession();
tx = session.beginTransaction();
session.save(location);
session.save(event);
// Use cascading to save the location


session.flush();
tx.commit();
System.out.println("Event and location saved!");
}
catch (HibernateException e)
{
try
{
if(tx != null) {
tx.rollback();
}
}
catch (HibernateException ignore)
{
//ignore
}
throw e;
}
finally
{
if(session == null)
{
try
{
session.close();
}
catch (HibernateException ignore)
{
//ignore
}
}
if(sessionFactory != null){
try
{
sessionFactory.close();
}
catch (HibernateException ignore)
{
//ignore
}
}
}
}
private static Date createDate(int year, int month, int day){
Calendar calendar = Calendar.getInstance();
calendar.set(year, month, day);
return calendar.getTime();
}
}[/quote]

Since the values you refer to are primary keys, the way in which they are generated depends on what generator mechanism you specified in the "id" section on your mapping file.
In your case, the mechanism would seem to be an Oracle sequence shared by both entities.

Hello gonzao_diaz
I got the problem, thanks for your reply.

I have specified generated as native, and when I run the ant task with schema export it creates a sequence, now I have a question in my mind how to create more than one sequence useing schema-export task, please help me.

Thanks and regards
Nitin Kalaskar

With "native", hibernate chooses what generation method to apply, depending on the capabilities of the underlying database. (in your case, a database sequence).
If you want it specifically to be a sequence, try "sequence", specifying a different sequence name inside each node

http://www.hibernate.org/296.html