Re: link same datamap to two different data nodes

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Sat Apr 26 2003 - 10:57:42 EDT

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    Hi Martin,

    No, it is not the Cayenne behavior to insert the same data into two
    databases in this case. In fact entities in DataMaps are used (among other
    things) as routing tokens to define the right DataNode to send query to.

    I was planning on writing some examples on how to use multiple databases
    with the same schema in Cayenne:

      http://objectstyle.org/cayenne/lists/cayenne-devel/2003/03/0176.html

    But I haven't started on this yet. But if you explain what problem you are
    trying to solve, maybe I or someone else on this list can provide some
    ideas. Do you really need to write the same exact data to the 2 databases?
    Is this for audit purposes or something? What about when you read it back,
    which database do you expect to respond?

    Andrus

    > hi..ll cayenne users,
    >
    > maybe you can help me with the following problem:
    >
    > i linked the same datamap to two different data nodes,
    > which represent two different databases; all stuff is
    > withing one data domain;
    >
    > i did expect, that cayenne inserts new persistent objects
    > into both databases, after comitting, but it does not ?!
    > cayenne inserts the objects into only one of the databases;
    >
    > is it possible to write simultaneously to two data nodes and if
    > yes, what is to do?
    >
    > thanx and so long
    >
    > marty



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