Re: Help! I need the magic no-cache recipe

From: Chris Gamache (cgamach..mail.com)
Date: Mon Jun 16 2008 - 10:36:33 EDT

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    For clarification:

    DataContext.invalidateObjects(...) What strategy would you use to
    invalidate everything?

    For .addPrefetch(String s), does s need to match the relation name in
    the xml files?

    And on a related note...

    What does "Max. Number of Shared Objects" actually limit, and what
    does the "Use Shared Cache" toggle do?

    If I set my "Max. Number of Shared Objects" to zero, or unchecked "Use
    Shared Cache" would that force Cayenne to hit the database every time
    a query was executed or a relation was fetched?

    On Tue, Jun 10, 2008 at 3:03 AM, Andrus Adamchik <andru..bjectstyle.org> wrote:
    > To control relationship refresh you can either use
    > DataContext.invalidateObjects(..) or plan a bit ahead and refresh it
    > together with the query that fetched the root object by using prefetching on
    > that relationship. E.g.
    >
    > someQuery.addPrefetch("relatedRows");
    > List rows = context.performQuery(someQuery);
    >
    > Judging from your example the prefetch option should be exactly what you
    > need.
    >
    > Andrus
    >
    >
    > On Jun 9, 2008, at 11:08 PM, Chris Gamache wrote:
    >>
    >> Using Cayenne 2.0.3 ...
    >>
    >> I'm having problems when I use an accessor to get rows from a related
    >> table. It pulls fresh data the first time I use the accessor, but if
    >> data is modified outside of the Java application, it is not reflected
    >> the next time I use the accessor in a different execution stack within
    >> the same JVM.
    >>
    >> List rowsA = context.performQuery(someQuery);
    >> ...
    >> SomeTable dataSetA = rowA.getRelatedRows();
    >> //object rowA and dataSetA and someQuery pass out of scope
    >> ...
    >> //Data is Modified directly on the database, not in Java application
    >> ...
    >> List rowsB = context.performQuery(theSameQuery);
    >> ...
    >> SomeTable expectedModifiedButGotSetA = rowB.getRelatedRows();
    >>
    >>
    >> The primary key which the relation uses to get the related data
    >> doesn't change from rowsA to rowsB. We're looking at the same related
    >> rowset, just updated data.
    >>
    >> I would like to know what is the magic no-cache recipe to force that
    >> particular accessor to always pull fresh data from the database...
    >>
    >> It appears that SelectQuery doesn't suffer from the same problem.
    >>
    >> I'm sure there's some configuration switches that I can trip, but
    >> there are several places caching policies can be modified and several
    >> confusingly similar yet different options to choose from.
    >>
    >
    >



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