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id setting issue

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pollux

Post subject: id setting issue

Posted: Fri Feb 15, 2008 5:24 am

Newbie

Joined: Fri Feb 15, 2008 5:05 am
Posts: 5
Location: Geneva

Good morning every body,

I've a little problem with the hibernate's id managing. I've learned in the reference documentation and in a book that I'm reading that when we persist an object, hibernate will associate the resulting id to the java object (depending on the id generator used).

In my testing code I use a native generator, so when I save the object, an insert occure immediately to retrieve the id. The id is returned by the save method but normally the id is set in the java object isn't it?... In my case... nothing happen. My object is correctly persisted but it doesn't have the id set.

I read, re-read the doc, I debug my code and hibernate, I searched in the forum, in the faq, on google... I didn't find why hibernate didn't init my id... Could anyone help me please?

Thanks in advance.

Hibernate version:3.2.5

Mapping documents:

Code:

<class name="Event" table="tevent">
    <id type="long">
        <generator class="native" />
    </id>
    <property name="title" type="string" />
    <many-to-one cascade="save-update" class="Speaker" column="speaker_id" name="speaker" />
</class>

Code between sessionFactory.openSession() and session.close():

Code:

tr = session.beginTransaction();
session.save(e);
tr.commit();
log.debug("ID Event = "+ e.getId());

Name and version of the database you are using: MySQL 5

The generated SQL (show_sql=true): insert into tevent (title, speaker_id) values (?, ?)

Debug level Hibernate log excerpt: DEBUG

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gishac

Post subject:

Posted: Fri Feb 15, 2008 10:35 am

Newbie

Joined: Fri Feb 15, 2008 5:07 am
Posts: 13

If your column is auto_increment you should change your generator to
<generator class="increment" />

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pollux

Post subject:

Posted: Fri Feb 15, 2008 11:29 am

Newbie

Joined: Fri Feb 15, 2008 5:05 am
Posts: 5
Location: Geneva

gishac wrote:

If your column is auto_increment you should change your generator to
<generator class="increment" />

Thank you gishac for your response.

Unfortunately, this doesn't work better. In my case, the id generation is correct, it's only the "binding" between the db and my pojo that doesn't work.

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ericp

Post subject:

Posted: Fri Feb 15, 2008 11:47 am

Newbie

Joined: Wed Feb 13, 2008 6:01 am
Posts: 8

Can you post the contents of the Event class and the top element of you hibernate mapping file i.e. <hibernate-mapping ........>

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pollux

Post subject:

Posted: Fri Feb 15, 2008 11:57 am

Newbie

Joined: Fri Feb 15, 2008 5:05 am
Posts: 5
Location: Geneva

ericp wrote:

Can you post the contents of the Event class and the top element of you hibernate mapping file i.e. <hibernate-mapping ........>

Of course.

Here is the top of the mapping file:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="org.poxd.entity">

and here is the content of the Event class:

Code:

package org.poxd.entity;

import java.io.Serializable;
import java.util.Set;
import java.util.jar.Attributes.Name;

public class Event implements Serializable{
   private static final long serialVersionUID = 1L;
   private Long id;
   private String title;
   private Speaker speaker;
   
   public Event() {
      this("", null);
   }
   
   public Event(String title, Speaker speaker) {
      this.title = title;
      this.speaker = speaker;
   }

   public Long getId() {
      return id;
   }
   public void setId(Long id) {
      this.id = id;
   }
   public String getTitle() {
      return title;
   }
   public void setTitle(String title) {
      this.title = title;
   }

   public Speaker getSpeaker() {
      return speaker;
   }

   public void setSpeaker(Speaker speaker) {
      this.speaker = speaker;
   }
   
   @Override
   public boolean equals(Object obj) {
      if (obj == this)
         return true;
      if (!(obj instanceof Event))
         return false;
      Event a = (Event) obj;
      if (a.id == this.id && a.title.equals(this.title))
         return true;
      return false;
   }
   
   @Override
   public int hashCode() {
      return this.title.hashCode();
   }
   
   @Override
   public String toString() {
      return title +" by " + speaker.getName();
   }
}

Last edited by pollux on Fri Feb 15, 2008 5:54 pm, edited 1 time in total.

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gishac

Post subject:

Posted: Fri Feb 15, 2008 12:17 pm

Newbie

Joined: Fri Feb 15, 2008 5:07 am
Posts: 13

pollux wrote:

gishac wrote:

If your column is auto_increment you should change your generator to
<generator class="increment" />

Thank you gishac for your response.

Unfortunately, this doesn't work better. In my case, the id generation is correct, it's only the "binding" between the db and my pojo that doesn't work.

It's strange i have the following configuration and hibernate bind's well the id in the object after insert

<id name="idRole" type="java.lang.Integer">
<column name="ID_ROLE" />
<generator class="increment" />
</id>

i'm using hibernate 3.1, how much is the diferrence between these versions?

:S

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pollux

Post subject:

Posted: Mon Feb 18, 2008 4:00 am

Newbie

Joined: Fri Feb 15, 2008 5:05 am
Posts: 5
Location: Geneva

This is really strange! It's fine with the version 3.1 and then when I tried with the 3.2 it went nice.... Odd... But tanks a lot!

Unfortunately I've always a problem.. Between the Event and the Attendee class I have a bidirectionnal relation. The retrieve of the Event's id is correct but for the attendees associated.... None id!... I don't understand.

Here is my Attendee class:

Code:

import java.io.Serializable;
import java.util.Set;

public class Attendee implements Serializable{
   private static final long serialVersionUID = 1L;
   private Long id;
   private String name;
   private Set<Event> events;

   public Attendee() {
      this("");
   }

   public Attendee(String name) {
      this.name = name;
   }
        
       //getter/setter

   @Override
   public int hashCode() {
      return name.hashCode();
   }

   @Override
   public boolean equals(Object obj) {
      if (obj == this)
         return true;
      if (!(obj instanceof Attendee))
         return false;
      Attendee a = (Attendee) obj;
      if (a.id == this.id && a.name.equals(this.name))
         return true;
      return false;
   }

   @Override
   public String toString() {
      return "[" + Attendee.class.getName() + " : " + getId() + " - " + getName() +" ]";
   }
}

In my Event class I just added a Set of Attendee member and its getter/setter and here is my mapping config:

Code:

<class name="Attendee" table="tattendee">
      <id type="long">
         <generator class="increment" />
      </id>
      <property name="name" type="string" />
      <set name="events" table="event_attendees" inverse="true">
         <key column="attendee_id" />
         <many-to-many class="Event" column="event_id"/>
      </set>
   </class>

...

<class name="Event" table="tevent">
      <id type="long">
         <generator class="increment" />
      </id>
      <property name="title" type="string" />
      <set name="attendees" cascade="save-update"
         table="event_attendees">
         <key column="event_id" />
         <many-to-many class="Attendee" column="attendee_id"/>
      </set>
   </class>

Somebody can help me?

Regards

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gishac

Post subject:

Posted: Mon Feb 18, 2008 11:34 am

Newbie

Joined: Fri Feb 15, 2008 5:07 am
Posts: 13

Did you try the lazy="false" attribute in atendee property?

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pollux

Post subject:

Posted: Mon Feb 18, 2008 11:40 am

Newbie

Joined: Fri Feb 15, 2008 5:05 am
Posts: 5
Location: Geneva

Thank you for your response but it's not better.

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