RE: Query certain attributes

From: Gentry, Michael (michael_gentr..anniemae.com)
Date: Thu Oct 21 2004 - 17:46:22 EDT

  • Next message: Andrus Adamchik: "Re: Query certain attributes"

    Of course. Probably the easiest way is to use one of the Expression
    methods:

    Expression expression = Expression.fromString("paintingTitle =
    $paintingTitle");
    Map parameters = new HashMap();

    parameters.put("paintingTitle", "Daisy Verve");

    SelectQuery query = new SelectQuery(Painting.class,
    expression.expWithParameters(parameters));
    List paintings = dataContext.performQuery(query);

    If you are actually wanting to limit the number of columns coming back,
    look at SQLTemplate in section 7.6 of the manual. You won't get
    DataObjects coming back, though, just raw data rows.

    /dev/mrg

    -----Original Message-----
    From: Williams, Beth [mailto:beth.william..FIB.ORG]
    Sent: Thursday, October 21, 2004 5:32 PM
    To: cayenne-use..bjectstyle.org
    Subject: Query certain attributes

    I have just started working with Cayenne and have a pretty basic
    question related to querying. Is there a way to only query certain
    attributes from a db table. From the examples I've seen so far
    (SelectQuery query = new SelectQuery(Artist.class);) all attributes are
    returned; equivalent to a SELECT * FROM xxx_table;. Is it possible (and
    if so, how) to query only certain attributes; equivalent to SELECT
    painting_title, estimated_price FROM painting;.

    Hope that makes sense. Thanks.

    Beth



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