Hello,

I'm sorry to ask again about this topic, but I've some problem to understand the way to use List with inverse="true".

There are many other posts on this (like http://forum.hibernate.org/viewtopic.php?t=330), but I think it could be interesting to have a clarification on this point (and add it to the FAQ).

With a mapping like this :

<list
name="associations"
lazy="true"
inverse="true"
cascade="all">
<key column="key"/>
<index column="idx" />
<one-to-many class="com.foo.Whatever" />
</list>

the index column is not updated to the database. So, what to do :
- map the index column and put manually the collection index into the mapped index field ?
- Use inverse="false" (what are the risks of this ?) ?
- What else

Thanks for the clarification.

Either of those work. The second might perform badly.

I absolutely busted my brain trying to figure out a way to implement this w/o the need for an "index property", so that it would work for detached objects, and w/o requiring buildtime bytecode tricks.

But there is no way, AFAIK.

Thanks for the quick answer.

[quote="Philippe Chal

Yes its bugprone. Still, if you implement it in a addChild() method, its doable.


I personally do *not* recommend using Lists for a Parent/Child type relationships. They are good for "weaker" relationships where you can use inverse="false".

Note that an *almost* correct implementation of the index() property is:




Though this does break when Parent is mapped with a proxy.

And that really is where all my problems with detached objects start. :(

I don't want to implement anything where we have to go back to the database to retrieve the value of the index column when I update() a Child with an uninitialized Parent.

And I don't want to give up Hibernate's model of startup-time SQL generation.

So I'm kinda stuck :(

Gavin, I just want to make sure I'm reading this correctly: the code is correct as long as parent is NOT mapped with a proxy, correct?

Thanks.

yeah, I think so.