At 11:49 20.02.2001 , you wrote:
>Hi Robert,
>
>I would like you to take this solution with a caveat. I also request to wait
>for the final specification before proceeding further on CMP component
>contract in EJB2.0.
is there any timeline (weeks, months?).
<snip/>
>1. What type of relationship - many-to-one bidirectional or many-to-one
>unidirectional - exists between PersonDoorAccess entity and Person entity ?
>
>2. Similarly what type of relationship - many-to-one bidirectional or
>many-to-one unidirectional - exists between PersonDoorAccess entity and
>Door entity ?
<snip/>
>With these questions in mind, lets consider the example in section 9.4.13 of
>Proposed Final Draft of EJB2.0 specification.
>I consider the relationship between Order and Product entity as
>many-to-many. An Order can be placed for many products, and a Product can be
>included in many orders. In this example, quantity of product ordered, etc
>are attributes of the many-to-many relationship. The example, in the PFD,
>model the relationship using LineItem entity and defining
>many-one-bidirectional relationship and many-to-one unidirectional
>relationship.
thanks for pointing that out. that's how we model it at the moment using
EJB 1.1 CMP. But that means that I will probably never have a direct
many-many relationship in my ejb2.0 model as we almost always have an order
attribute in the relationship, that has to be manipulated my clients. So
the current state of the spec is as I suspected. Relationship attributes in
many-many relationships can only be modelled indirectly by making the
relationship an entity (or dependent object). Let's see what the expert
group is going to come up with.
thanks and best 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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