Re: auto-prefetch in a toMany?

From: Craig L Russell (Craig.Russel..un.COM)
Date: Mon Oct 22 2007 - 11:26:37 EDT

  • Next message: Andrus Adamchik: "Re: auto-prefetch in a toMany?"

    On Oct 22, 2007, at 4:39 AM, Andrus Adamchik wrote:

    > Actually JPA allows to specify that certain relationships are
    > always "eagerly fetched"

    true

    > (although it doesn't have a concept of prefetching in the queries)...

    There is an explicit "fetch join" in JPA queries that you can use to
    explicitly eagerly fetch related entities.

    Craig

    > I haven't thought yet how we may handle that in Cayenne, but that
    > feature is essentially what you are asking for. (But of course
    > it'll be quicker to hack the getter, like you suggested).
    >
    > Andrus
    >
    > On Oct 22, 2007, at 2:26 PM, Tore Halset wrote:
    >> Hello.
    >>
    >> We have a to-many relationship that is used all over the
    >> application. Each time someone goes over that to-many relationship
    >> they want to take a look at the next to-many relationship as well.
    >>
    >> A <-->> B <-->> C
    >>
    >> To make this faster, I want to prefetch the relationship from B to
    >> C each time someone goes from A to B.
    >>
    >> Is this possible by just overriding A.getBs() without loosing the
    >> positive sides of faulting? I think I want the ToManyList to use
    >> prefetches in its underlying SelectQuery.
    >>
    >> Regards,
    >> - Tore.
    >>
    >

    Craig Russell
    Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
    408 276-5638 mailto:Craig.Russel..un.com
    P.S. A good JDO? O, Gasp!





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