Re: entities with calculated fields

From: Aristedes Maniatis (ar..sh.com.au)
Date: Tue Feb 20 2007 - 06:21:29 EST

  • Next message: Andrus Adamchik: "Re: entities with calculated fields"

    On 20/02/2007, at 1:43 AM, Andrus Adamchik wrote:

    >> I think Andrus is the right person to answer your question, but I do
    >> recall a conversation where the intention was for derived dbentities
    >> to be removed.
    >
    > True - that was an ugly and limited workaround. We do need to get
    > rid of it.

    Would you like me to create a task that we mark the API and
    documentation mentions of it as deprecated? Would a goal be to
    replace this with something like:

    http://developer.apple.com/documentation/LegacyTechnologies/
    WebObjects/WebObjects_4.5/System/Documentation/Developer/
    EnterpriseObjects/EOTools/DerivedProperties1.html

    or do you think that SQLtemplates are the catch all for this?

    >> SQLTemplate can also work with data objects, just need to make sure
    >> the object properties match the returned column names. The SQL
    >> template has a nice facility to support multiple database versions as
    >> well.
    >
    > Yep, that would be my recommendation as well.

    I've read the docs but I don't quite understand how this mapping back
    to an object entity will work. If I use the #result notation to
    specify all the attributes already in the _Artist.class and I then
    add something like paintingCount to Artist.class, how do I then tell
    the SQLtemplate to return that derived attribute into paintingCount?

    #result('COUNT(SELECT ...)' 'int' paintingCount)

    Will that do it? Is the columnAlias mapped to the attribute in the
    object entity?

    Ari

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