Hi Krish,
well I have the impression that all those are workarounds for something
that could be solved rather easily by the spec authors. Fact is, that
relationship attributes are commonplace in many-many-relationships and that
everyone implements them some way. Viewing the relationship as an object
(as in the case of modelling the relationship as an entity) IMHO is a
rather object-oriented approach, yet it's rather heavyweight. IMHO all
that's missing is the definition of a semantically clean way of accessing
relationship attributes. The way we implement it today on top of EJB1.1 is
as follows:
we have three entities (suppose the many-many relationship is bidirectional)
Person
Door
PersonDoorAccess
in the remote interface of Person we have methods:
Collection getAccessibleDoors(); (implemented lazily using finders on top
of the CMP engine)
PersonDoorAccess getPersonDoorAccess(Door); (also implemented with finders,
throwing ObjectNotFound if there is no relationship between the two)
in analogy in Door we have
Collection getPersonsWithAccess();
PersonDoorAccess getPersonDoorAccess(Person);
in PersonDoorAccess we have stuff like get/setPIN() or get/setLastAccessed()
This works very well for us in practice as navigating the relationship is
efficient because no intermediate steps are taken and editing the
relationship attributes is easy but I would whish for something similar to
be part of the CMP contract for relationships. Let's wait and see what the
next iteration of the spec will bring.
regards,
robert
At 10:42 20.02.2001 , you wrote:
>Hi Robert,
>
>I think there could be another approach to what you
>described, and this is what we (at our organization)
>use. (ejb spec 1.1 though ... i am looking at the 2.0
>but at the moment i don't see any solution there)
<snip/>
(-) 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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