Re: re-opening the DESCRIBE issue

On Wed, Mar 29, 2006 at 04:06:31PM -0600, Dan Connolly wrote:
> 
> In reviewing our request for CR,
>   http://www.w3.org/2001/sw/DataAccess/crq349
> there was a lot of concern about interoperability
> around DESCRIBE. TimBL took a close look at CBD
> and MSG from
> http://semanticweb.deit.univpm.it/submissions/www2005/WWW2005_signignRDF.pdf
> and looked briefly at GK's recent proposal
>  http://www.w3.org/mid/4427D376.9070504@ninebynine.org
> and concluded that this issue merits considerable further work.
> We talked about the possibility of postponing the issue
> and marking the DESCRIBE syntax "reserved for future use"
> and he was supportive of that.
> 
> The issue is hereby re-opened.
> http://www.w3.org/2001/sw/DataAccess/issues#DESCRIBE
> 
> I look forward to proposals to close/postpone it. I gather Andy is
> available to discuss them only thru this Friday.
> 
> There's still a reasonably good chance that we can get
> a SPARQL CR out next week, if we come to consensus on
> something quickly.

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. 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.
]]
-- 
-eric

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