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Re: re-opening the DESCRIBE issue

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Mon, 3 Apr 2006 11:11:44 -0400
Message-Id: <1dc5594024683d27e86c00b363513591@isr.umd.edu>
Cc: Dan Connolly <connolly@w3.org>, RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: "Eric Prud'hommeaux" <eric@w3.org>

On Apr 3, 2006, at 10:56 AM, Eric Prud'hommeaux wrote:
[snip]
> I propose the following text:
> [[ http://www.w3.org/2001/sw/DataAccess/rq23/#describe
> 10.4 Descriptions of Resources
>
> Current conventions for DESCRIBE constrain it to return an RDF
> graph.

You mean the specification? Isn't there reason to leave that a bit 
open, e.g.,
	DESCRIBE according to CBF as HTML

I.e., why put in *this* constraint (convention?)?

>  Future SPARQL specifications may further constrain the results
> of DESCRIBE, rendering some currently valid DESCRIBE responses
> invalid.
>
> [ Non-normative: The DESCRIBE form returns a single result RDF graph
> containing RDF data about resources. This data is not prescribed by a
> SPARQL query, where the query client would need to know the structure
> of the RDF in the data source, but, instead, is determined by the
> SPARQL query processor. The query pattern is used to create a result
> set. The DESCRIBE form takes each of the resources identified in a
> solution, together with any resources directly named by IRI, and
> assembles a single RDF graph by taking a "description" from the target
> knowledge base. The description is determined by the query service. ]
>
> An empty graph is a valid response to any DESCRIBE query.
> ]]

I don't like the non-determinism this introduces. That is, there should 
be a difference between not having any valid answers and just not 
handling DESCRIBE.

Cheers,
Bijan.
Received on Monday, 3 April 2006 15:11:57 GMT

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