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Re: [All] Proposal: RDF Graph Identification

From: David Wood <david@3roundstones.com>
Date: Fri, 17 Aug 2012 09:48:57 -0400
Cc: public-rdf-wg@w3.org
Message-Id: <08847D4F-B80E-4710-A472-25AA106C2A0D@3roundstones.com>
To: Andy Seaborne <andy.seaborne@epimorphics.com>
On Aug 17, 2012, at 07:37, Andy Seaborne <andy.seaborne@epimorphics.com> wrote:

> On 16/08/12 16:45, Ivan Herman wrote:
>> 
>> On Aug 16, 2012, at 16:23 , Peter F. Patel-Schneider wrote:
>> 
>>> OK, let me throw out the first counter-proposal.
>> 
>> :-) This is not a counter proposal, just a reduction...
>> 
>>> 
>>> I find that this document goes quite a bit beyond what I think is necessary or desirable to support named graphs.  I propose instead a minimalist version of graph identification.  I will describe this minimalist version by stripping away pieces of the document.
>>> 
>>> Major changes:
>>> 
>>> 1/ No mutability:
>>> 
>>> Mutability is not required for named graphs or graph stores.  To effect this change, excise the first part of Section 2, Section 2.1, and Section 2.4.  Also fix up the abstract and Section 1.
>>> 
>>> I am somewhat ambivalent about whether the working group should do anything about mutability, but I am sure that the working group should not tie mutability to named graphs and certainly not to datasets.
>>> 
>> 
>> It is indeed the question whether mutability should be mentioned. The reason we thought of retaining this is because SPARQL has already introduced this with the differences between data stores and datasets. As the diagram shows this means that there is something 'missing' in the RDF related concepts (something that became also clear at the very beginning of the group's life when the term g-boxes were introduced) to make the picture complete. Indeed, the group may decide not to do anything here, but I still feel that the overall picture would be incomplete...
>> 
>> It is all SPARQL's fault!:-)
> 
> :-)
> 
> In SPARQL Update, graphs are not mutable.

I have no idea what anyone means when they use the bare word "graph" anymore.  In SPARQL Update, I do see:

Section 2: "A Graph Store is a mutable container of RDF graphs managed by a single service." [1]
Section 4.1.1: "A Graph Store GS is a mutable container of RDF graphs… The Graph Store can be viewed as a mutable RDF Dataset." [2]

I believe that is consistent with the RDF Graph Identification proposal's Figure 1.

Regards,
Dave


[1] http://www.w3.org/TR/sparql11-update/#graphStore
[2] http://www.w3.org/TR/sparql11-update/#def_graphstore


> 
> What's more, the definitions would work if a graph store contained a datasets and update was replace one dataset (value) by another.  An update operations changes on graph store state to another by definign the new dataset state. The spec no longer talks about changes to a slot.  It is however, a useful way to explain things.
> 
> 
> RDF could just no mention mutability.  On balance, some text in "concepts" to give an overview is useful; it does not need to be continued.  RDF specs define what is, not operations.  Implementers seem to have got on just fine with RDF-2004, and that program language "sets" are (with care) mutable does not cause problems.
> 
> 
> "concepts" should mentioned SPARQL if it is to continue its rule as the first, non-primer, port of call.
> 
> 
> Like Steve, the name "space" does not work for me either because of, for example, "data spaces".  We aren't naming from a clean sheet.
> 
> "container" works for me in the figure.  Something with the idea of containing (like 'slot' graph store).  "box"?
> 
> 	Andy
> 
Received on Friday, 17 August 2012 13:49:25 UTC

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