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Re: http-rdf-update and the default graph

From: Steve Harris <steve.harris@garlik.com>
Date: Thu, 30 Sep 2010 08:12:46 +0100
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <FE44E77A-04E9-4DFE-9398-7ED68DED9A34@garlik.com>
To: Andy Seaborne <andy.seaborne@epimorphics.com>
FWIW 4store uses ?graph=default: but that's a hack as it kind of gives the default graph a URI, it was just easier for the CGI hander to cope with.

?default seems OK.

- Steve

On 2010-09-29, at 22:55, Andy Seaborne wrote:

> In implementing http-rdf-update, I need to also address the default graph of a graph store, for POST and GET.
> 
> I have been using the absence of ?graph= to mean the default graph
> 
> http://host/dataset?graph=http://example/graph1
> http://host/dataset
> 
> but this is wrong because to look at it another way, the URI before the query string is the name of the graph store, not the default graph.  GET http://host/dataset might usefully return N-Quads.
> 
> Is this the right way to view it or should I be using some thing like:
> 
> http://host/dataset?default
> 
> At one level, this is an extension to http-rdf-update because http-rdf-update does not cover addressing the default graph of a graph store, but at the same time, it would be good for implementations to do the same thing.
> 
> "Network-manipulable Graph Store" excludes the default graph but I don't see an rationale for this.  If it had been just a collection of graphs, not a graph store, then the absence of an un-named one is explicable, but the document directly discusses graph stores and whether a URI identifies the underlying network-manipulable Graph Store.
> 
> A simple additional naming form would expose the default graph.
> 
> 
> Related to this:
> 
> Section 8:
> 
> [[
> It is RECOMMENDED that the web address of SPARQL 1.1/Service Descriptions be specified.
> ]]
> 
> This confused me.  Earlier, the text used the URI as the graph store, not the service (description).  We seem to have update and/or query service at the same place as the graph store.  This would be OK, as services are split by HTTP query string, but not if the graph store is GETtable and there is a service description to return.
> 
> For http-rdf-update, I'd suggest it's the graph store (RDF dataset) that is on the web.  The service model is more appropriate for SPARQL Update language and query.
> 
> 
> Minor editorial:
> 
> 5.4 HTTP GET
> mentions graph store without the network-manipulable qualification.
> 
> 	Andy
> 
> 

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Received on Thursday, 30 September 2010 07:13:19 GMT

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