Re: delete rule for flatten relationship?

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Wed Aug 27 2003 - 18:08:23 EDT

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    On Wednesday, August 27, 2003, at 05:19 AM, Tore Halset wrote:
    > Hello
    >
    > A<<-->a_in_b<-->>B are flattened to
    > A<<-->>B
    >
    > What are the best way to delete a A? Deleting the A should delete all
    > entries in a_in_b for the given A.

    This situation is indeed not handled by Cayenne. I will open a bug
    report. Just need to define the right criteria for automatically
    deleting join records. Any ideas are welcomed (one being an explicit
    setting of additional delete rule on a flattened relationship).

    For now delete rules for tables that do not map to an ObjEntity may be
    specified at the database level. I think even MySQL has some limited
    support for row delete rules (?)

    > I have tried with delete rule nullify, but it did not work. I am afraid
    > that a cascade (on the A-->>B relation) will delete all B's.

    Exactly. Delete rule will have no effect on the join table in case of
    flattened relationships.

    Andrus

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