Hi guys,

I really tried to found the answer myself, but I'm not wiser after reading the documentation:
My problem is:

I want to map a class, but no table exist for that class.

Class Segment {}
Class MyType{}

Class SegmentR extends Segment {
Integer id
Collection myCollectionOfMyTypes
}

I want to map SegmentR, something like this:
<class segmentR>
<bag><one to many MyType></one-to-many> </bag>
</class>

I want to do this, because other subclasses have tables, but this one doesn't , and I want to write general methods, not distinguishing the concrete subclass. Simply, to be as transparen as I can. Thanks.

p.s. to hibernate team: don't give up ;)


Hibernate version:

Mapping documents:

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

Full stack trace of any exception that occurs:

Name and version of the database you are using:

Debug level Hibernate log excerpt:

I guess you're looking for a inheritance mapping. Chapters 5.1.13, 5.1.14 of the reference manual have more infos about this.
The new Hibernate in Action Book has also a very nice description in chapter 3.6.

HTH
Ernst

I don't think so.
Clearly, it's possible to declare a parent-child relationship where no table exists for parent.

But I don't see any possibility to declare a composition relationship(so Parent contains some type), where no table exists for parent.

Please, if you know any solution, post it.

Do I get you right? SegmentR acts as a template for subclasses. There will probably never be an instance of type SegmentR (if yes, using abstract class or interface is a good idea).

Best Regards
Ernst

no...

ok, I'll try to explain it simplier:

I have a class, let's say MyClass. Myclass contains some objectc, which are mapped in hibernate, and works 100% fine.

But there is no table for myclass. Altought, I want to define it in Hibernate. I want to tell hibernate:
Here's MyClass, which has these object types. If I tell load(Myclass), create an instance of myClass, and load all it's objects. If I say save(myClass), don't do anything, or throw an exception.

I know, It's possible to say
<class name="thisClassDoesNotHaveTable">
<subclass name"butThisOneHas">

but I want to map:
<class "thisClassWithNoTable>
<property name="ClassWithTable" type....>

any idea?is it possible?

Ok, I got it!

I don't think Hibernate suports this, but I'm not 100% sure. (Can one of the experts confirm this?)

You could do this by using the DAO pattern.

Let's assume you have MyParent-->MyChild, with no table for MyParent (which means it's not persistent).

For MyParent write a InMemoryMyParentDAO, for the MyChild write a HibernateMyChildDAO. Now the InMemoryMyParentDAO can load its children via the HibernateMyChildDAO in the getter method. I think would be to hard to even implement a kind of cascade all between the two.

HTH
Ernst

No, this is not possible. How should hibernate know which objects are associated to your MyClass. You can only load classes which have actually a table associated (or are superclasses of persistent classes, via polymorphic queries)

ok, thanks both of you guys.