I would not call it that no.

For me the question is ... for a *ToMany path do you ever want to supply a
filter on that path (or conversely do you ALWAYS want to get ALL the beans
for that path (so this really only applies to the *ToMany paths).

So, lets say each customer had tens of thousands of Orders ... maybe we
think it is too expensive to practically navigate from customer to orders...
so perhaps you never allow it and remove the orders property from the
Customer entity bean and make it uni-directional.  *You have just modified
your ORM model purely due to cardinality.*

You then always have to navigate your model the other way - from order to
customer.

You would indeed build a similar object graph but it not exactly the same.
Your root objects are Orders and not Customers - and if you want to process
Customers primarily (with their new orders) you have some work to do to find
the list of unique customers first and then ...

Note that you never do this in the relational model - the relationship still
exists no matter the cardinality - and you can still use SQL to join both
ways.

That would be good. The generated SQL will clarify things.

blowing away all the records I didn't load?

Yes you can. You assumption is correct.

Hmmm, I'll have a look at that (I'd suggest that is a bug).

... but first I want to clarify that we do want the ability to apply a
filter on the *ToMany (and not having that ability can be a real problem).
Aka that we should get 1 role in the list and not 2 (and if you wanted to
filter the users in this case we should use a subquery ... and that should
actually match the SQL that is generated by the JPA query).

Cheers, Rob.

On Fri, Mar 5, 2010 at 2:22 AM, Daryl Stultz <kungfumachin...@gmail.com>wrote: