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Problem updating a collection

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ulfreich

Post subject: Problem updating a collection

Posted: Tue Nov 23, 2004 11:26 am

Beginner

Joined: Tue Sep 21, 2004 1:49 pm
Posts: 33
Location: Bogota, Colombia

Hi, consider an object A that has a one-to-many collection of B objects. Usually when I set an entire collection to an object (A.setBs(set);) what it does is deleting all the items in the collection and adding the new ones, which generates a delete in sql that eliminates the records and then an insert that creates the new ones. The problem I'm having is that the deletion doesnt occur so, if my collection has objects B1, B2 and B3, and I eliminate B3, the result is B1, B2, B1, B2. (the new collection to be set has B1 and B2 and thus it duplicates them)

(I've done this same operation with other classes and it works just fine.. but I cant find any difference. Need I check my equals() and hashcode() in the B class?)

Has anyone been here before? thanks..

Hibernate version: 2.1.2

Mapping documents:
A:

Code:

    <class
        name="A"
        table="As"
        dynamic-update="false"
        dynamic-insert="false"
        select-before-update="false"
    >

    (...)

        <set
            name="Bs"
            lazy="false"
            inverse="true"
            cascade="save-update"
            sort="unsorted"
        >
            <cache 
                usage="read-write" 
             />

              <key
                  column="A_ID"
              >
              </key>

              <one-to-many
                  class="B"
              />

        </set>

    </class>

Code:

    <class
        name="B"
        table="Bs"
        dynamic-update="false"
        dynamic-insert="false"
        select-before-update="false"
    >

        <many-to-one
            name="AObj"
            class="A"
            cascade="none"
            outer-join="auto"
            update="true"
            insert="true"
            access="property"
            column="A_ID"
        />

    </class>

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

Code:

   public void updateBs(A item, HashSet set)
      throws HibernateException, BusinessException {

      if (item == null) log.debug("****** A IS NULL *******");
      log.debug("Updating Bs for A: " + item.getId());

      log.debug("Set size: " + set.size());

      item.setBs(set);
      HibernateUtil.getSession().update(item);
      log.debug("Done.");
   }

Full stack trace of any exception that occurs: No Exception. Just the insert without the previous delete.

Name and version of the database you are using: Oracle 9i

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ulfreich

Post subject: An update

Posted: Tue Nov 23, 2004 12:17 pm

Beginner

Joined: Tue Sep 21, 2004 1:49 pm
Posts: 33
Location: Bogota, Colombia

An update..

Reading the log in detail, I found this: In my logic I first update the properties of the A object and then try to update its set of Bs before flushing. In the log I found that when I save the A object it cascades saveOrUpdate over the Bs collection:

Code:

2004-11-23 10:48:05,792 DEBUG [net.sf.hibernate.impl.SessionImpl] updating [com.edesa.matri.persistence.Inscripcion#44]
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.engine.Cascades] processing cascades for: com.edesa.matri.persistence.Inscripcion
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.engine.Cascades] cascading to collection: com.edesa.matri.persistence.Inscripcion.instituciones
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.engine.Cascades] cascading to saveOrUpdate()
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.engine.Cascades] id unsaved-value strategy NULL
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.impl.SessionImpl] saveOrUpdate() previously saved instance with id: 80
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.impl.SessionImpl] updating [com.edesa.matri.persistence.Opcion#80]
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.engine.Cascades] cascading to saveOrUpdate()
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.engine.Cascades] id unsaved-value strategy NULL
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.impl.SessionImpl] saveOrUpdate() previously saved instance with id: 72
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.impl.SessionImpl] updating [com.edesa.matri.persistence.Opcion#72]
2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.engine.Cascades] cascading to saveOrUpdate()

(...)

2004-11-23 10:48:05,823 DEBUG [net.sf.hibernate.engine.Cascades] done processing cascades for: com.edesa.matri.persistence.Inscripcion

So, when I try to set the new collection it says:

Code:

2004-11-23 10:48:06,026 DEBUG [net.sf.hibernate.impl.SessionImpl] object already associated with session

Then it inserts the new collection over the other. :S

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ulfreich

Post subject: Monologue.

Posted: Tue Nov 23, 2004 1:34 pm

Beginner

Joined: Tue Sep 21, 2004 1:49 pm
Posts: 33
Location: Bogota, Colombia

Well I made it work but I dont think it's the best way to do it, I'd appreciate some advise on it..

I changed my code to this:

Code:

public void updateBs(A item, HashSet set)
   throws HibernateException, BusinessException {

   if (item == null) log.debug("****** A IS NULL *******");
   log.debug("Updating Bs for A: " + item.getId()); 
   log.debug("Number of Bs: " + set.size());

   // Eliminates current Bs from A.
   item.setBs(null);

   // Eliminates A's Bs from database.
   String q = "from B b " +
      "where b.a.id = " + item.getId();
   HibernateUtil.getSession().delete(q);

   // Adds the new Bs.
   item.setBs(set);
   HibernateUtil.getSession().update(item);
   log.debug("Done.");
}

I dont think it looks so healthy.. is there a way to make it simpler?

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