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Re: SPARQL Update - Clarifying correct behavior when a graph is created implicitly

From: David Booth <david@dbooth.org>
Date: Tue, 01 Nov 2011 10:44:52 -0400
To: Lee Feigenbaum <lee@thefigtrees.net>
Cc: public-rdf-dawg-comments <public-rdf-dawg-comments@w3.org>, eric neumann <eneumann@pangenx.com>, Ian Emmons <iemmons@bbn.com>
Message-ID: <1320158692.8545.1030.camel@dbooth-laptop>
Yes, I am satisfied with this resolution.  

Thank you,
David

On Tue, 2011-11-01 at 10:29 -0400, Lee Feigenbaum wrote:
> Hi David,
> 
> In response to: 
> http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2011Sep/0008.html
> 
>  > Therefore, I suggest adding some clarification to this effect at the end
>  > of the first paragraph in section 3.1:
>  > http://www.w3.org/TR/sparql11-update/#graphUpdate
>  > [[
>  > If a graph is created implicitly by an update operation, then the
>  > behavior of the Graph Store MUST be functionally equivalent to its
>  > behavior if the graph had been created explicitly by a CREATE operation.
>  > ]]
> 
> We have adopted this suggestion in the latest editor's draft:
> 
> http://www.w3.org/2009/sparql/docs/update-1.1/Overview.xml#graphUpdate
> 
> and would kindly ask you to acknowledge that this addresses your comment.
> 
> best,
> Lee
> On behalf of the SPARQL WG
> 
> On 9/13/2011 6:40 PM, David Booth wrote:
> > The SPARQL Update spec indicates that "If data is inserted into a graph
> > that does not exist in the graph store, it *should* be created":
> > http://www.w3.org/TR/sparql11-update/#insertData
> > However, I've run into an issue with one implementation (Parliament
> > 2.7.1) in which the graph *is* created automatically in such
> > circumstances, but the graph is not persisted in the store unless it was
> > created explicitly using a CREATE operation.
> >
> > For example, the following query creates the named graph whether line 3
> > is commented out or not:
> >
> >    PREFIX test:<http://example/test/>
> >    DROP SILENT GRAPH test: ;
> >    CREATE SILENT GRAPH test: ;   # Line 3
> >    INSERT DATA
> >    {
> >      GRAPH test: { test:foo a test:bar }
> >    }
> >
> > But if line 3 is commented out, then the graph is not persisted.
> >
> > I consider this a bug (and I assume the Parliament implementers will
> > also, though I have not heard back from them yet) because it would lead
> > to substantial compatibility issues for SPARQL update queries if some
> > implementations persisted the graph and others did not.  But AFAICT, the
> > SPARQL Update spec does not make clear that this behavior is wrong.
> >
> > Therefore, I suggest adding some clarification to this effect at the end
> > of the first paragraph in section 3.1:
> > http://www.w3.org/TR/sparql11-update/#graphUpdate
> > [[
> > If a graph is created implicitly by an update operation, then the
> > behavior of the Graph Store MUST be functionally equivalent to its
> > behavior if the graph had been created explicitly by a CREATE operation.
> > ]]
> >
> > Thanks!
> >
> >
> 
> 

-- 
David Booth, Ph.D.
http://dbooth.org/

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Received on Tuesday, 1 November 2011 14:45:29 GMT

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