Suppose I have something like this:

Table T1 with primary key (common_id, T1_ID)

Table T2 with primary key (common_id, T2_ID)

and an association table A3 modeling a many-to-many relation between
T1 and T2. A3 has primary key (common_id, T1_ID, T2_ID), and
two foreign keys: (common_id, T1_ID) =>T1, and
(common_id, T2_ID) =>T2. Note that both foreign keys
share the "common_id" column.

When I try to map this in hibernate, I try to construct
the class for A3 using a composite-id something like this:

<composite-id>

<key-many-to-one name="T1">
<column name="common_id"/>
<column name="T1_ID"/>
</key-many-to-one>

<key-many-to-one name="T2">
<column name="common_id"/>
<column name="21_ID"/>
</key-many-to-one>

</composite-id>


However, when I try to use a mapping like the above, I get an error about common_id
being a repeated column, and the message suggests that I
use update="false" and insert="false" in defining the property. That doesn't
really make sense for a composite-id, though.

So, is there actually a way to map these three tables into three classes? (other
than some kind of crazy hack, like defining a view that gives two different names
to the same column or something like that.)

Thanks for shedding any light.

I've the same problem the key of my new object is a reference to two objects wich have a composite-id having a repeated column.

Thanks

To begin with, I don't think <key-many-to-one> is really that nice a feature. So, first, get rid of that ;-)

Create a pk class, FooBarKey, with the 3 pk attributes:



We should add something like this to the wiki or doco or faq...

Yes I've bypassed the problem in a similar way. Leaving only one object in the key and a property. And the other object in the class.

But from the objects view it's not the best solution I've to duplicate code. Will this be improved in the version 3? It will be an interesting feature.

Thanks