Adam,
Thanks, this looks nice. However I have the problem that I want to use
"GROUP BY" in my statements which is a kind of a problem as the "defined
finder" methods requires that exact the same parameters are returned which
isn't true in case of "GROUP BY" (the Sum() returns something that isn't in
the orginally resultset).
How can I still receive the result set form this Group by statement ?
I was thinking about defining an entity bean that contains the fields that
the Group by statement returns, but how ??? (Just like the elefantwalker
mentioned: have another entitybean that performs all the heavy stuff)
Can someone help me with this, as I don't knwo what the xml definition of
this entity bean should look like, as untill now was using simple entity
beans that are directly related to database tables, which isn't true in this
case.
Eddie
----- Original Message -----
From: Adam Cassar <[EMAIL PROTECTED]>
To: Orion-Interest <[EMAIL PROTECTED]>
Sent: Tuesday, April 17, 2001 3:41 AM
Subject: Re: findBy referencing another entity reference
>
> I found this reply to an earlier posting quite usefull.
>
> http://www.mail-archive.com/[email protected]/msg12085.html
>
> On 16 Apr 2001 17:23:15 -0700, Rian Schmidt wrote:
> > Oh boy... OK, maybe that was a bad example. "Read more about entity
beans"
> > is not very useful advice in any case. I just didn't want to explain
our
> > business model to ask the question.
> >
> > Try the situation where the top level is Vehicle -> Manufacturer ->
Model or
> > something many-to-many on each layer. My point is that I want to be
able to
> > "skip a layer" in the finder. Is that possible? If you don't know, or
the
> > answer is no, please just say that or ignore my question and move on.
If
> > you have an actual answer or alternative approach that might work, I'd
be
> > very appreciative to hear it.
> >
> > For what it's worth, I want to do it this way, as opposed to using some
kind
> > of bean-based (logical model) test or pseudo-BMP thing because, due to
the
> > volume of "3rd level (in my example)" entities running a findAll on them
is
> > performance-limiting and I'd rather not stick SQL directly in my beans.
> >
> > Thanks,
> > Rian
> > --
> > Rian Schmidt
> > [EMAIL PROTECTED]
> >
> > ----- Original Message -----
> > From: "elephantwalker" <[EMAIL PROTECTED]>
> > To: "Orion-Interest" <[EMAIL PROTECTED]>
> > Sent: Monday, April 16, 2001 2:54 PM
> > Subject: RE: findBy referencing another entity reference
> >
> >
> > > Rian,
> > >
> > > This is much too sql centric. You should resolve your entity beans
around
> > > business methods. So I would start off by reading more about entity
beans.
> > > Theserverside.com, for example has a download on an excellent book for
> > > entity beans. As for the sql, you are talking a one to one
relationship
> > for
> > > the car/model and a one to many relationship for the
manufacturer/model.
> > > There should be some examples of this on the sun's j2ee site. I know
that
> > > they specifically discuss this issue.
> > >
> > > Regards,
> > >
> > > the elephantwalker
> > >
> > >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED]
> > > [mailto:[EMAIL PROTECTED]]On Behalf Of Rian Schmidt
> > > Sent: Monday, April 16, 2001 2:23 PM
> > > To: Orion-Interest
> > > Subject: findBy referencing another entity reference
> > >
> > >
> > > Hi all,
> > >
> > > How about this scenario:
> > > There are three entities: manufacturer, model, car (as an example)
> > > model knows directly which manufacturer it is, car knows which model
it
> > is,
> > > but car has to do a model.getManufacturer to find out its
manufacturer...
> > >
> > > OK, so what I wanna know is can I a findByManufacturer for car? I'd
> > > like to be able to do something like this:
> > > query="$model.manufacturer = $1"
> > >
> > > Now, I know that I could specify a sub-query with the actual
persistence
> > > name of the other entity's thang, something like:
> > > query="$model in (select $model from model where manufacturer_id =
$1)"
> > > but it strikes me that Orion won't know what I'm going on about, and
best
> > > case, will have to talk to the database each time. Either way, I had
to
> > put
> > > the persistence name into the orion-ejb-jar.xml file, which is not
> > goodness.
> > >
> > > Is it possible maybe to say something like:
> > > query="model in ($1)"
> > > where $1 is a Collection of models taken from
> > ModelHome.findByManufacturer?
> > >
> > > Any thoughts on the best way to approach this?
> > >
> > > Thanks,
> > > Rian
> > > --
> > > Rian Schmidt
> > > [EMAIL PROTECTED]
> > >
> > >
> > >
> >
> >
> >
>
>
>
> --
>
> Adam Cassar
> Technical Development Manager
> ___________________________________________
> NetRegistry http://www.netregistry.au.com
> Tel: +61 2 9641 8609 | Fax: +61 2 9699 6088
> PO Box 270 Broadway NSW 2007 Australia
>
>
>
