More explanation on key-many-to-one

scesbron · **Joined:** Thu Sep 04, 2003 8:23 am **Posts:** 368

Hi,

In the book there is a sentence about key-many-to-one that says

Quote:

However, it's usually inconvenient to have an association in a composite identifier class, so this approach isn't recommended except in special circumstances

Is it possible to have any explanation on this. Why it is not recommended to use 'key-many-to-one' ?

Thanx for your help

Seb

christian · **Posted:** Fri Nov 05, 2004 5:39 pm

Well, key-many-to-one just sucks in Hibernate. Use a key-property and a many-to-one mapped with update/insert=false.

scesbron · **Joined:** Thu Sep 04, 2003 8:23 am **Posts:** 368

So this is just an hibernate restriction ?

I don't like your proposition because the new property is just here for an hibernate purpose. It pollutes my domain model.

Maybe there is another solution. I have a parent/child relationship. I want the child pk to be a composition of the parent id and another relation.

For me the best way to design this with hibernate is to use a composite-element. My problem is just a schema generation relative problem. I cannot with this design generate a pk on my composite-element table. So I tried to do it with a one-to-many relation but this leads me in a key-many-to-one on the child element. I am so just curious on why this is a bad idea.

If somebody can tell me how to generate my pk on my child table with a composite-element I think this would be the best way to do

Thanx

Seb