Many To Many relations: how to?

From: Claudio Rosati (claudio.rosat..csys.it)
Date: Thu Jul 01 2004 - 09:02:44 EDT

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    Hello all,
     
    I have two classes, Record and Collocation, that should have a many-to-many
    relation, like the one in the picture.
     
    Class diagram
     
    Each class is backed by a corresponding DbEntity (records and collections).
    These entities contains just one attribute: a primary key VARCHAR[64] one
    called uid, reflected into the corresponding class as the uid String
    attribute.
     
    What I would like is the situation depicted, where when I add a Collocation
    to a Record using the addToCollocations method, the corresponding list of
    Records in the Collocation object is updated automatically.
     
    Being ignorant about DBs and their management (this is why I'm using
    Cayenne), I don't understand if it is possible and how to realize it with
    Cayenne (and its modeler): I need to add some attributes to the DbEntities
    (which one?), I need to add helper tables (whicwh one?), Which kind of
    relation I need to set up...?
     
    Thanks in advance for any help.
     
    Claudio
     
     

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    Claudio Rosati
    Project Manager Advanced Computer Systems S.p.A.
    via Della Bufalotta 378
    00139 Roma, RM
    Italy
    claudio.rosat..csys.it
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