Hibernate: Mapping multiple classes to same table

Question

Consider a Transport table with 3 fields: Engine Wheels Wings

If Engine and Wheels are non-null and Wings is null then I wish to map this to a Vehicle class If Engine and Wings are non-null and Wheels is null then I wish to map this to a Plane class

I have been reading about discriminators to differentiate between subclasses but in any of the examples that I've read, they always refer to a discriminator value. Therefore, I'm wondering how I can go about my above scenario? Do I just implement separate mappings? I was hoping to find a neater way.

Thanks

Edit

Have just looked through the reference guide again and have noticed that null and not-null are valid values. So looks like this solves my problem. Will leave this open for a little while to confirm. Thanks!

Elias Dorneles · Accepted Answer · 2012-03-31 03:43:55Z

1

You can create an abstract parent class for your Plane and Vehicle classes and use @DiscriminatorFormula, which you use to write a formula that generates a value that you can later annotate as the @DiscriminatorValue for the Plane and Vehicle subclasses.

Take a look at this example in the Hibernate docs (though this example uses XML for the mapping, it's basically the same thing for the annotation):

http://docs.jboss.org/hibernate/core/3.6/reference/en-US/html/example-mappings.html#example-mappings-content-discrimination

answered Mar 31, 2012 at 3:43

Elias Dorneles

24.2k12 gold badges91 silver badges112 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Hibernate: Mapping multiple classes to same table

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related