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Re: Dereferencing a URI vs querying a SPARQL endpoint

From: Hugh Glaser <hg@ecs.soton.ac.uk>
Date: Wed, 20 May 2009 18:12:08 +0100
To: Daniel Schwabe <dschwabe@inf.puc-rio.br>, "public-lod@w3.org" <public-lod@w3.org>
CC: "semantic-web@w3.org" <semantic-web@w3.org>
Message-ID: <EMEW3|62f24e1e9a0e98fea886dc253476dc88l4JICM02hg|ecs.soton.ac.uk|B361%hg@ecs.soton.ac.uk>
I think sitemap may already have what you want.
We use slicing="subject-object"
For our sets such as:
(See http://acm.rkbexplorer.com/sitemap.xml).

http://sw.deri.org/2007/07/sitemapextension/
Says:

The <sc:linkedDataPrefix> and <sc:sparqlEndpointLocation> tags can have an optional slicing attribute that takes a value from the list of slicing methods below.

slicing="subject"
The description of a resource X includes the triples whose subject is X.

slicing="subject-object"
The description of a resource X includes the triples whose subject or object is X.

slicing="cbd"
The description of a resource X includes its Concise Bounded Description.

slicing="scbd"
The description of a resource X includes its Symmetric Concise Bounded Description.

slicing="msgs"
The description of a resource X includes all the Minimal Self-Contained Graphs involving X.



On 20/05/2009 17:59, "Daniel Schwabe" <dschwabe@inf.puc-rio.br> wrote:

Dear all,

while designing Explorator [1], where one can explore one or more triple repositories that provide SPARQL enpoints (as well as direct URI dereferencing), I found the following question, to which I don't really know the answer...

For the sake of this discussion, I'm considering only such sites, i.e., those that provide SPRQL enpoints.
For a given URI r, is there any relation between the triples I get when I dereference it directly, as opposed to  querying the SPARQL enpoint for all triples <r, ?p, ?o> ?  Should there be (I could also get <?s, ?p, r>, for example) ?
For sites such as dbpedia I believe that I get the same set of triples. But I believe this is not a general behavior.
Should there be a good practice about this for LoD sites that provide SPARQL endpoints?
At the very least, perhaps this could also be described in the semantic sitemap.xml, no?

Cheers
D

[1] http://www.tecweb.inf.puc-rio.br/explorator
Received on Wednesday, 20 May 2009 17:13:41 UTC

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