> I'm trying to do a very simple read-ahead for a
> particular relationship mapped via a relationship
> table. Unfortunately, I can't add key fields when I
> use a <read-ahead>.... But I need both sides of the
> relationship-role populated for the relation-table!
>
> has anyone done that before?

You lost me. You can eagerload a multivalued field (cmr), but you can lazy load across the relationship. I personally consider this a design flaw, and I plan on fixing it in 4.0.

> As a side comment to the excellent JBoss people, the
> JBoss CMP doc is good, but I wonder if detail
> coverage of optimised loading would be useful for
> people with lots of relationships and not so much
> findBy method? Because in an ideal OO world, you
> would walk your object trees rather than doing a lot
> of findBy (which is more like doing raw sql).

Yes in an ideal 00 world you would walt the tree, but we live in a relational world. This means the optimal way to deal with relationships is to execute a query that "jumps" to the desired data. Remember that at the end of the day your are dealing with an array of bytes on a disk.