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Re: Service Description document

From: Andy Seaborne <andy.seaborne@talis.com>
Date: Tue, 27 Apr 2010 16:09:51 +0100
Message-ID: <4BD6FE3F.6020103@talis.com>
To: Gregory Williams <greg@evilfunhouse.com>
CC: SPARQL Working Group WG <public-rdf-dawg@w3.org>


On 27/04/2010 9:15 AM, Andy Seaborne wrote:
>
>
> On 27/04/2010 3:24 AM, Gregory Williams wrote:
>> The second issue is one involving the naming of named graphs in a
>> dataset description. Sandro had brought this up at the F2F, and I hope
>> he can weigh in on it. Basically, I had the modeling in the document
>> like this:
>>
>> [] a sd:Dataset ;
>> sd:namedGraph [
>> sd:name<graph-uri> ;
>> sd:graph [ ... graph description goes here ... ] ;
>> ]
>>
>> I believe Sandro's concern was the use of the URI<graph-uri> since
>> we're not actually talking about the resource, but instead a name that
>> we've locally given to the graph (hopefully he'll correct me if I'm
>> mis-characterizing this). Instead, he suggested that it should be
>> "graph-uri"^^xsd:anyURI. If we adopt this change then the document
>> should clarify the rdfs:range of the sd:name property and the Example
>> section should be updated accordingly.
>
> I'm not sure this is helpful. The named graph paper uses URIs, as do
> TriG and NQuads, as well as SPARQL query. They don't use xsd:anyURI.
>
> The "local name" idea does not seem to me to get round the issue for
> xsd:anyURI as it's still associating a global identifier with the graph,
> even if it's not web-naming it. The use in a web document means we still
> have a global reference to the thing.


Test case: should this work:

query the service description doc and choose a graph to match based on that:

# Default graph = service description
# Named graphs = all the named graphs

SELECT *
{
    [] a sd:Dataset ;
      sd:namedGraph
     [
       sd:name ?g ;
       sd:graph ... some condition ... ]

    GRAPH ?g { ?s ?p ?o }
}



or using SERVICE:

FROM <description for X>

SELECT *
{
     # Choose the graph(s) of interest:
    [] a sd:Dataset ;
      sd:namedGraph
     [
       sd:name ?g ;
       sd:graph ... some condition ... ]
    # Go ask them ...
    SERVICE <X> { GRAPH ?g { ?s ?p ?o } }
}

	Andy
Received on Tuesday, 27 April 2010 15:10:24 GMT

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