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Re: Sorting

From: Danny Ayers <danny.ayers@gmail.com>
Date: Tue, 8 Mar 2005 22:49:36 +0100
Message-ID: <1f2ed5cd05030813496305efd5@mail.gmail.com>
To: Dan Connolly <connolly@w3.org>
Cc: public-rdf-dawg-comments@w3.org, Leigh Dodds <leigh@ldodds.com>

On Tue, 8 Mar 2005 15:08:16 -0600, Dan Connolly <connolly@w3.org> wrote:
> 
>  > Is it the case then that Sparql will not include an ORDER BY or
>  > similar clause? If not, then would it be possible to elaborate
>  > why?
> 
> We adopted a LIMIT requirement over an objection (details below), but
> sorting has never had a critical mass of support. It competes with
> streaming results (http://www.w3.org/2001/sw/DataAccess/UseCases#r3.12
> ). We haven't discussed any designs for sorting.

I don't understand why sorting should compete with streaming - isn't
the transport at a different layer than order?

> You're welcome to elaborate on why you think it's important/required.
> Use cases are particularly welcome, especially use cases that argue for
> handling sorting in SPARQL rather than in a downstream component or
> client or XSLT engine or the like.

Use case: obtain a given number of most-recent items from a
triplestore-based RSS aggregator. (Something along the lines of
http://pubsub.com which aggregates data from several million feeds -
they use ASN.1 internally btw, though expose XML interfaces).

I may be missing something, but the most natural way I can think of
doing this is using a combination of ORDER BY and LIMIT.

Cheers,
Danny.

-- 

http://dannyayers.com
Received on Tuesday, 8 March 2005 21:49:38 GMT

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