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Re: Dereferencing a URI vs querying a SPARQL endpoint

From: Daniel Schwabe <dschwabe@inf.puc-rio.br>
Date: Wed, 20 May 2009 23:25:59 -0300
Message-ID: <4A14BBB7.9050308@inf.puc-rio.br>
CC: semantic-web@w3.org, public-lod@w3.org
Kingsley Idehen wrote:
> Pierre-Antoine Champin wrote:
>> I would expect that a DESCRIBE query to the SPARQL endpoint return what
>> I get when dereferencing the URI.
>>
>>   pa
>>   
> Daniel,
>
> Is this your problem:
>
> Linked Data Servers publish URIs. The mechanism that delivers these 
> URIs tends to vary since they are the product of URL-rewrite rules 
> that may or may not be associated with SPARQL queries, and when SPARQL 
> Query based you may be dealing with a CONSTRUCT or a DESCRIBE.
If a URI actually refers to an RDF document, I would imagine there is no 
URL rewriting involved; it resolves to the document itself. And for 
SPARQL based, who knows what I may be dealing with? Peter already 
exemplified that you may get something that is neither a CONSTRUCT nor a 
DESCRIBE...

>
> Ideally, you would like to be able to discern via SPARQL, what SPARQL 
> query patterns sits behind the re-write rule for a given 
> de-referencable URI.
Basically yes, although I'm not even requiring being able to do it 
directly via SPARQL (that would be actually nice)...
Also, I'd be curious to know what is more efficient - dereferencing or 
issuing the query through the endpoint.

Cheers
D

>
Received on Thursday, 21 May 2009 02:26:39 UTC

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