Hello: I'm a student and I need your help because my proyect depend on hibernate.

I have a one problem when I try to recovery a set from one-to-many relationship.

I have 3 classes: Alumno, Ramo and RamoAlumno. RamoAlumno is intermediate class, because in my model I have
Alumno--many-to-many--Ramo, and I have propieties in the relation.

Then, I have 2 relations from RamoAlumno

Alumno -- one-to-many -- RamoAlumno

and

Ramo -- one-to-many -- RamoAlumno

if I recovery one Alumno (Alumno is subclass of Persona):
Query q = sess.createQuery("from Persona r where r.rut = :rut");
q.setString("rut", rut);
Alumno p = (Alumno) q.uniqueResult();

and I load one Ramo:

Ramo r = (Ramo) sess.load(Ramo.class, id_ramo);

and I create a new RamoAlumno

RamoAlumno rp = new RamoAlumno();
rp.setEstado(estado); //one propiety of RamoAlumno
rp.setSemestre(sem); //other
rp.setAgno(agno); //and other
rp.setAlumno(p); // this is for relation to Alumno
rp.setRamo(r); // and Ramo
sess.save(rp); // this work
p.getRamo_alumno().add(rp); // this work fine
r.getRamo_alumno().add(rp); // this don't work

sess.getTransaction().commit();

This cause a big problem in the application, because I can't recovery set from one class. Neither I can to do

RamoAlumno.getRamo().getId(); // this don't work :(

to do join
if(RamoAlumno.getRamo().getId()==r.getId())

In the schema of database, RamoAlumno have all propieties and fk belong to Alumno and Ramo.

In summary, Why when I have one class with 2 or more relationships (RamoAlumno) just one relation work fine??? The other relation is dead?

Previously, I put others post about this problem, with others case.

Please, help.

Hibernate version: Hibernate 3.1.3

Mapping documents:

Alumno is a subclass of Persona:

<joined-subclass name="encuestas.Alumno" table="ALUMNO">
<key column="ALUMNO_ID"/>

(propieties.....)

<set name="Ramo_alumno"
lazy="true"
inverse="true"
cascade="delete" >
<key>
<column name="alumnoID" />
</key>
<one-to-many class="encuestas.RamoAlumno"/>
</set>

</joined-subclass>
</class>

</hibernate-mapping>


Ramo.hbm.xml

<?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>
<class name="encuestas.Ramo" table="RAMO">

<id name="id" type="long" column="ID">
<!-- <meta attribute="finder-method">findByID</meta> -->
<generator class="native"/>
</id>
(propieties....)

<set name="Ramo_alumno"
lazy="true"
inverse="true"
cascade="delete" >
<key>
<column name="ramoID" />
</key>
<one-to-many class="encuestas.RamoAlumno"/>
</set>


</class>

</hibernate-mapping>


RamoAlumno.hbm.xml

<?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>
<class name="encuestas.RamoAlumno" table="RAMO_ALUMNO">

<id name="id" type="long" column="ID">
<!-- <meta attribute="finder-method">findByID</meta> -->
<generator class="native"/>
</id>

<property name="semestre"
type="string"
not-null="true"
update="false">
<column name="SEMESTRE"/>
</property>
<property name="agno"
type="int"
not-null="true"
update="false">
<column name="AGNO"/>
</property>
<property name="estado"
type="string"
not-null="true"
>
<column name="ESTADO"/>
</property>

<many-to-one
name="alumno"
class="encuestas.Persona">
<column name="alumnoID" not-null="true" />
</many-to-one>

<many-to-one
name="ramo"
class="encuestas.Ramo"
>
<column name="ramoID" not-null="true" />
</many-to-one>

</class>

</hibernate-mapping>


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

Ramo r = (Ramo) sess.load(Ramo.class, idp);
out.println("xxxxx");

for (Iterator it = r.getRamo_alumno().iterator(); it.hasNext();) {
out.println("yyyyy");
RamoAlumno ra = (RamoAlumno) it.next();
out.println("<p>Alumno: "+ra.getAlumno().getNombre());
}

}
}


sess.getTransaction().commit();


Full stack trace of any exception that occurs:

Name and version of the database you are using:
Mysql 5.0.22-Debian_0ubuntu6.06.2

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

Thank you.

Well typically you'd do something like the following:

Ramo r = session.load(...);
Alumno p = session.load(...);

Transaction transaction = sess.getTransaction();
transaction.beginTransaction();
RamoAlumno rp = new RamoAlumno();
rp.setEstado(estado);
rp.setSemestre(sem);
...
r.add( rp );
p.add( rp );
transaction.commit();

And inside your methods you'd have:

class Ramo {

public void add( RamoAlumno ra ) {
ramoAlumnos.add( ra );
ra.setRamo( this );
}
}

and vice versa for your Alumno class with a similiar method.

Remember when you use inverse=true on your one-to-many relationships Hibernate won't modify the DB when you change those. You have to modify the RamoAlumno object for hibernate to notice there has been a change that needs to be saved to the DB. That's why it's a good idea to do the above code and encapsulate those calls behind a method so you don't forget to modify the persistant side of the relationship.

I wonder if you tried removing the session.save() call and just let everything commit when the transaction is committed if it would work.

Charlie