Re: to-many & List

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Thu Jun 03 2004 - 14:05:21 EDT

  • Next message: Glover, Tony (Contractor-ELMCO): "Cayenne and MS Access"

    There are two ways to get a list of objects - (1) via an explicit query
    or (2) via a to-many relationship. Mike was referring to the first
    case, while Bill is likely talking about the second.

    Well, lists obtained via relationships are using whatever order the
    database provides. At some point we wanted to implement an ordering as
    an optional property of the relationship in the DataMap. However there
    was some disagreement with folks who volunteered to do that, so this
    hasn't been done. I still think that we need this feature, so sooner or
    later this will be implemented.

    Andrus

    On Jun 3, 2004, at 1:04 PM, Bill Dudney wrote:

    > Thanks Mike,
    >
    > I was really wondering about the to-many relationships that cayenne is
    > building. So I have A->B and the relationship is to-many. Cayenne
    > builds a List, the DB does not specify an order of B's so either
    > Cayenne is just using whatever order the Bs come from the DB or its
    > ordering them in some way.
    >
    > I'd assume its in whatever order they are coming from the DB but
    > wanted to ask.
    >
    > Thanks again for all your help!
    >
    > -bd-
    >
    > On Jun 3, 2004, at 10:58 AM, Mike Kienenberger wrote:
    >
    >> Bill Dudney <bdudne..ac.com> wrote:
    >>> Hi Andrus,
    >>>
    >>> Does Cayenne then assume some ordering or is it just the arbitrary
    >>> order that comes from the db? Is it possible for me to specify the
    >>> 'order by' key?
    >>
    >> Same methodology as in EOF.
    >>
    >> http://www.objectstyle.org/cayenne/userguide/fetch/orderings.html
    >>
    >>
    >> You might also find this comparison between EOF and Cayenne useful.
    >>
    >> http://www.objectstyle.org/cayenne/userguide/misc.html
    >
    >



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