Hi,

I have a class that consists of a one-to-one mapping class and a one-to-many mapping class. No own table is required for that class. So this class doesn't require a key column by its own, but can use a key-property of the mapped (one-to-one) class.

My question is how I can express this in my associated *.hbm.xml-File. Do I have to use a composite-id? (But it's only one key- property needed) Is it possible to use the <id> tag with a costum type?

Using Hibernate 2.

Thanks for help,
Joerg

I don't really get you. Does component or collection of value does what you need ?

My class A look like this:


No other variables are required. B and C are hibernate mapped classes. A doesn't require its own table. What I'm searching for is a mapping for A like this:




What I need is an <id> for A. This identifier should be the same as the Identifier of class B. Is there a way to map that id?

Kind of
use <id> with foreign generator and <one-to-one constrained="true"/>
check the doc for appropriate details

Emmanuel, thanks for your support.
Is it necessary to declare a variable id for A? In my modell it would be better to use the identifier of class B in a way such as A.B.id instead of A.id. Your proposal means to map the values of A.B.id to A.id, is this correct? Is there a way to avoid A.id?

Joerg

No there is no way to avoid a.id (you can set it as private however)

Thats not entirely correct, you need an <id> mapping for every entity (value/component mappings of course don't), but not an identifier property (not even a private) in your persistent classes. Detached objects won't work without, however.