RE: Query on a Single Primary Key`

From: Lindsay Steele (lsteel..inet.net.au)
Date: Mon Sep 13 2004 - 03:25:05 EDT

  • Next message: Joćo Paulo Vasconcellos: "Handling DataObjects"

    It helps a lot .. Worked straight away ...

      Thanks heaps.

         Lindsay

    -----Original Message-----
    From: Andrus Adamchik [mailto:andru..bjectstyle.org]
    Sent: Monday, 13 September 2004 12:02 PM
    To: cayenne-use..bjectstyle.org
    Subject: Re: Query on a Single Primary Key`

    Hi Lindsay,

    DataObjectUtils is the way to go. I will write some documentation for
    it for the upcoming release, but it is very simple to use (see API at
    http://objectstyle.org/cayenne/api/cayenne/org/objectstyle/cayenne/
    DataObjectUtils.html). Here is one example:

    DataContext context = ...;
    Artist artist = (Artist) DataObjectUtils.objectForPK(context,
    Artist.class, 5);

    Hope this helps

    Andrus

    On Sep 12, 2004, at 3:41 AM, Lindsay Steele wrote:
    >
    > I have to do a query for a single object. The only way to identify
    > this object is to use it's primary key.
    >
    > It is just showing the details for that object.
    >
    > I have read through previous mailing list posts .. And have come up
    > with two ways of doing this ...
    >
    > One solution was something like this ...
    >
    > Expression expExtn =
    > ExpressionFactory.matchDbExp("EXTENSION_NO_PK_COLUMN", extn);
    >
    > This does not seem to work .... It comes back with the following
    > error
    > ..
    >
    > "[v.1.1B2 July 25 2004] Can't resolve path component:
    > [extension.EXTENSION_NO_PK_COLUMN]"
    >
    > I also see another solution being giving that is said to be even
    > better. It is to use
    > the DataObjectUtils class. I am not exactly sure how to implement
    > this though ?? I like to see code examples
    > of how something is being done.
    >
    > Does anyone have any code examples on how to use the DataObjectUtils
    > .... Or can they see anything wrong with the matchDbExp I am trying
    > use.
    >
    > Thanks,
    >
    > Lindsay
    >
    >
    >
    >
    >



    This archive was generated by hypermail 2.0.0 : Mon Sep 13 2004 - 03:25:22 EDT