Hibernate version:3.1 Beta
Name and version of the database you are using:oracle 9i

I have an entity called "SCHOOL", which is associated (ONE TO MANY relation) to an entity called "STUDENT" that inherited from the abstract entity called "PERSON".
The code of the entities is like this:

The Person entity:
@Entity
@Table(name="PERSON")
@Inheritance(discriminatorValue="1", strategy=InheritanceType.SINGLE_TABLE, discrimunatorType=DiscriminatorType.INTEGER)
@DiscriminatorColumn(name="TYPE")
public abstract class Person imlements Serializable {
...
}

The Student entity:
@Entity
@Inheritance(discriminatorValue="2")
public class Student extends Person imlements Serializable {
...
}

The School entity:
@Entity
@Table(name="SCHOOL")
public class School imlements Serializable {
...
@OneToMany(targetEntity=Student.class, mappedBy="school")
public List<Student> getStudents() {
return students;
}
}

When I used merge to the master entity, I get all the kinds of Persons to the students list and not just the Students as I would expect.
I'm trying a lot, but couldn't undersatnd why it merges like this.
By the way, when I merge the Student without association it works great.

Thanks, Roni[/quote]

The Person entity:
@Entity
@Table(name="PERSON")


@Inheritance(discriminatorValue="1", strategy=InheritanceType.SINGLE_TABLE, discrimunatorType=DiscriminatorType.INTEGER)
@DiscriminatorColumn(name="TYPE")


==> Try this : here you should NOT specify any descriminator for the parent abstract class since it has not to be instantiated ... only concrete subclasses need to be"descriminated" ...

Please keep me informed of the result !



public abstract class Person imlements Serializable {
...
}

The Student entity:
@Entity
@Inheritance(discriminatorValue="2")
public class Student extends Person imlements Serializable {
...
}

The School entity:
@Entity
@Table(name="SCHOOL")
public class School imlements Serializable {
...
@OneToMany(targetEntity=Student.class, mappedBy="school")
public List<Student> getStudents() {
return students;
}
}

Thank for your reply.

I have tried to create the abstract entity without the discriminator value to the Person entity as you offered, but it didn't pass compilation without this.
This is the reason I added this also to the abstract entity.
I'll happy to get other ideas..

Roni

Please provide your XML mapping files instead of xDoclet tags. I feel more confortable with that.

Anyway, try this : since the Person class is abstract you do not really need to map it to the table person.

Just map Student to PERSON table in the usual way (but keep the inheritance in your java code) ; in case you have an additional concrete subclass, map it also in the usual way independently from the Student class.

In the mapping files use the attribute where="descriminator=1" to descriminate Student from the other concrete subclass in Table Person.

This is a very correct work around ... (I recently faced a similar issue I could solved this way).