RE: ordering and path expression

From: Gentry, Michael \(Contractor\) ("Gentry,)
Date: Wed Aug 31 2005 - 13:17:21 EDT

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    I don't believe:

      ordering.orderList(p.getStudies());

    Will actually update the DataObject's list. So, the next time you do a p.getStudies(), you'll get the original list in it's original order.

    That's why I was suggesting using a cover method in your Patient class. Something like:

    public List getStudies()
    {
      List studies = super.getStudies();
      Ordering ordering = new Ordering("studydate", true);
      ordering.orderList(studies);
      return studies;
    }

    Of course, you could optimize that a bit, too (cache the sorted list). You'd also want to cover the addTo/etc methods if you do cache things, so you could keep the cache in-sync.

    /dev/mrg

    -----Original Message-----
    From: Arnaud Garcia [mailto:arnaud.garci..im.hcuge.ch]
    Sent: Wednesday, August 31, 2005 12:05 PM
    To: cayenne-use..bjectstyle.org
    Subject: Re: ordering and path expression

    thanks for help Michael,

    It still does not work, I try with a in Memory, but no difference ...
    this is my latest version:

    Expression exp = ExpressionFactory.matchExp(patientid, "1234");
    query = new SelectQuery(Patient.class, exp);
    query.addPrefetch(_Patient.STUDIES_PROPERTY);
    // query.addOrdering("studies.studydt", true); // nice but not work,
    however the sql request is ok, but certainely the fetch problem!!
     List patients = context.performQuery(query);

    // So, now I try a in Memory sort: For each patient, I get all his
    studies and try or order them by "studydate" (the getter or study.class),
    //
    for (int i = 0; i < patients.size(); i++) {
                Patient p = (Patient) patients.get(i);
                Ordering ordering = new Ordering("studydate", true); //
    Instead of the getter studydate I tried with studydt (obj-entity
    attribute) but no diff
                ordering.orderList(p.getStudies());
            }

    any idea ?
    thanks
    arnaud

    Gentry, Michael (Contractor) a écrit :

    >Ah, the orderings only apply to the returned object(s). In your case,
    >you are asking for a Patient with an ID of 1234. Only one object is
    >coming back in your List. Your studies will be prefecthed, but will be
    >in "random" order (to the best of my knowledge).
    >
    >The easiest way to handle this is to add a cover method in your subclass
    >(the non-underscore Patient.java) to do an in-memory sort of the studies
    >and use that method to get them in the order you want.
    >
    >Look at
    >http://www.objectstyle.org/cayenne/userguide/fetch/orderings.html to see
    >how to do the in-memory sort.
    >
    >/dev/mrg
    >
    >
    >-----Original Message-----
    >From: Arnaud Garcia [mailto:arnaud.garci..im.hcuge.ch]
    >Sent: Wednesday, August 31, 2005 10:10 AM
    >To: cayenne-use..bjectstyle.org
    >Subject: ordering and path expression
    >
    >
    >Hi,
    >
    >I would like to know how to use the ordering function with path
    >expression in my queries.
    >My objects are "Patient.class" with a list of "study.class" objects wich
    >
    >has a studydate getter (a simple one to many relationship)
    >
    >I want to retrieve my patients (by ID) with all the studies ordering by
    >date (the date is a filed of Study.class),
    >
    >My code:
    > Expression exp = ExpressionFactory.matchExp(patientid, "1234");
    > query = new SelectQuery(Patient.class, exp);
    > query.addPrefetch(studies);
    > query.addOrdering(".....???...", true); // maybe something
    >like: toPatient.study.studydate
    > List patients = context.performQuery(query);
    >
    >many thanks for help
    >
    >arnaud
    >
    >
    >
    >

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