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Re: Comments on SPARQL Query Results XML Format

From: Bob MacGregor <bmacgregor@siderean.com>
Date: Wed, 23 Mar 2005 10:15:41 -0800
Message-ID: <4241B24D.8010200@siderean.com>
To: Arjohn Kampman <arjohn.kampman@aduna.biz>
CC: public-rdf-dawg-comments@w3.org



Arjohn Kampman wrote:

>
> Dear all,
>
> Here's another round of feedback, this time on the query results format.
> The feedback is based on version 1.20 (2005/02/28) of the editor's
> draft.
>
> * The current specification only lends itself for encoding bindings of
>   values to variables. This is due to the fact that variable names are
>   used as tag names. If, at some point in time (but hopefully soon:-)),
>   the SPARQL language is changed to allow functions and/or operators in
>   the projection, the format as it is defined now is no longer usable.
>   To be a little more specific: if SPARQL would allow functions and/or
>   (aggregation) operators in the SELECT-clause, then the query result
>   can no longer be seen as a variable binding. Some (pseudo-) examples
>   to clarify this:
>
>   Q1: SELECT COUNT(X), Y WHERE ... GROUP BY ...
>
>   Q2: SELECT concat(X,Y), sum(A,B) WHERE ...
>
>   IMHO, it would be wise to create a format that is more flexible with
>   respect to such future extensions.

Good point.  I think that SQL allows numbers as a substitute for 
attribute names in
deciphering output,  We could do the same (e.g., support C_1, C_2) or 
somesuch
to allow referencing any position in a select clause.

Cheers, Bob
Received on Wednesday, 23 March 2005 18:16:24 GMT

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