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From Dave Dombrosky <dom...@gmail.com>
Subject Re: Order By Expression
Date Tue, 16 Mar 2010 17:33:01 GMT
Yes I'm using Cayenne 3.  I'm not sure if I stated the problem in
enough detail, because it seems like you guys are confused.  Or maybe
I just don't understand how to use what you are telling me about.

Maybe it would be better if I was helped with a full example.  Using
the Artist class from Cayenne's test schema, how would I go about
creating a SelectQuery to order all artists with the name "Tom" first?
 Basically to generate a query similar to this:

SELECT * FROM artist ORDER BY artist_name = 'Tom' DESC;

Would it be like this?

SelectQuery query = new SelectQuery(Artist.class);
query.addOrdering("artistName = 'Tom'", SortOrder.DESCENDING);
context.performQuery(query);

Because that still gets the error Unsupported ordering expression:
artistName = 'Tom'.

Am I doing something wrong, or is this impossible with a SelectQuery?
I'd rather not use SQLTemplate if I can avoid it.

-Dave

On Tue, Mar 16, 2010 at 8:39 AM, Michael Gentry <mgentry@masslight.net> wrote:
> Hi Dave,
>
> Since you are seeing deprecation warnings I'm assuming you are using
> Cayenne 3?  If so, you should use:
>
> addOrdering(Ordering ordering) or
> addOrdering(String sortPathSpec, SortOrder order)
>
> These are defined for your SelectQuery object.  Of course, if you are
> using the first of those methods, you'll have to create your own
> Ordering object first.  The second creates one for you behind the
> scenes.
>
> Let me know if you need additional pointers!
>
> mrg
>
>
> On Tue, Mar 16, 2010 at 1:11 AM, Dave Dombrosky <dombrd@gmail.com> wrote:
>> Is there any way to use sort expressions in a query?  Something like
>> "ORDER BY column = id"?  I get the error "Unsupported ordering
>> expression" when trying to execute a query with this in it.
>>
>> Also, it looks like I might be able to do this using in-memory
>> sorting, but the Ordering(Expression sortExpression, ...) methods are
>> deprecated.  So what's the preferred way to sort on expressions in
>> Cayenne?
>>
>> -Dave
>>
>

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