Perhaps this is one of the areas under revision... My experience has been
that non-database developers don't always get this issue right away.
You could model it as a dependent object of one of the entities, but cascade
delete behavior could be very expensive. Making it an entity in it's own
right probably isn't a big win either.
Cheers
Jay Walters
-----Original Message-----
From: Robert Krueger [mailto:[EMAIL PROTECTED]]
Sent: Monday, February 19, 2001 2:57 PM
To: [EMAIL PROTECTED]
Subject: Re: Modeling relationships with attributes with EJB2.0 CMP
At 13:20 19.02.2001 , you wrote:
>On Mon, 19 Feb 2001, Robert Krueger wrote:
>
> > Say I have an entity Person and an Entity Door and a relationship
> > PersonDoorAccess with multiplicity many-many. Then things like
lastAccessed
> > and PIN would be modelled as an attribute of that relationship. I don't
see
> > any way of doing that using EJB2.0 CMP except for modeling the
relationship
> > PersonDoorAccess as an entity itself.
>It sounds like a dependent of either Person or Door to me.
its life cycle is not necessarily controlled by just one entity, so I think
dependent doesn't apply here.
> >
> > Is there an obvious reason why relationship attributes don't seem to be
> > supported? Is my modeling approach wrong?
> >
> > It would be great if anyone who's closer to the specifcation process
could
> > enlighten me where my mistake is.
>I'm no closer to the spec. process than you, but I have heard rumors that
>there will be substantial changes before the spec. is final.
yes, don't know which source you're referring to but rickard oberg
mentioned that on the jBoss list I think. he didn't mention what areas,
though (probably can't without getting in trouble).
regards,
robert
(-) Robert Krüger
(-) SIGNAL 7 Gesellschaft für Informationstechnologie mbH
(-) Brüder-Knauß-Str. 79 - 64285 Darmstadt,
(-) Tel: 06151 665401, Fax: 06151 665373
(-) [EMAIL PROTECTED], www.signal7.de
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