- From: Antoine Zimmermann <antoine.zimmermann@gmail.com>
- Date: Thu, 14 Apr 2011 21:36:55 +0200
- To: Pat Hayes <phayes@ihmc.us>
- CC: Ivan Herman <ivan@w3.org>, RDF Working Group WG <public-rdf-wg@w3.org>
Our decision today was about SPARQL datasets and what the URI in the <n,G> pairs is referring to. We said it does not necessarily identify the graph in the sense of what the RDF semantics says (the interpretation of n does not need to be the graph). This is enough to define a notion of interpretation and model of a dataset, as explained in section "Interpreting datasets" of http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs/RDF-Datasets-Proposal. Now, the use cases clearly show that we need a way to identify a graph (or rather a g-box) with a URI. My understanding was that this is independent from today's decision, and I hope it is. So all is good so far. Le 14/04/2011 19:09, Pat Hayes a écrit : > Well, the use of a URI inside an RDF triple assumes that the URI is > being used as a name, to refer to something. Using a URI which is the > name of a named graph, for example, would refer to the graph. But in > this decision we *explicitly* say that this is *not* how the SPARQL > association of URIs to graphs works: that the 'associated' graph > which is 'tagged' (if I have that right) by a URI might well not be > the entity referred to by the URI. The example was given in which the > URI is the name of a person, ie refers to a person, and still can be > used to 'tag' a graph for SPARQL purposes. If such a URI is used as > the object of an RDF triple, it will refer to the person, not to the > SPARQL-tagged graph. As there is no way to know whether the graph > that is SPARQL-tagged by a URI is, or is not, the referent of the > URI, any use of that URI as a name inside an RDF triple must be > basically unrelated to its use as a SPARQL graph tag; or at any rate, > that is the only safe assumption to make. > > In a nutshell, RDF uses URIs as referring names. Apparently, SPARQL > does not, when it comes to identifying graphs. So the uses of URIs in > RDF triples and in SPARQL tags are dissociated from one another, and > need have no relationship. So, no relationship can be relied upon. > The 'naming' of graphs in SPARQL is a wholly SPARQL-local business, > unrelated to RDF semantics and therefore to any RDF content. > > I assumed this was obvious at the time we were discussing this, by > the way. But I confess I had not at that time read the Wiki proposal > fully, and not seen the 'imports' examples. > > Pat > > On Apr 14, 2011, at 11:55 AM, Ivan Herman wrote: > >> Pat, >> >> sorry, but you will have to explain (me) what the problem is. >> >> Ivan >> >> ---- Ivan Herman web: http://www.ivan-herman.net mobile: +31 64 >> 1044 153 >> >> On 14 Apr 2011, at 18:43, Pat Hayes<phayes@ihmc.us> wrote: >> >>> I note in passing that the Proposed WG Decision dated 14 April >>> has the consequence that the IRi associated with a graph in >>> SPARQL cannot be used inside an RDF triple to reliably refer to >>> the graph. This means in particular that uses such as those >>> contemplated in >>> http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs/RDF-Datasets-Proposal, >>> which use the SPARQL name as the object in an 'imports' triple, >>> are ruled out by this decision. >>> >>> Pat >>> >>> On Apr 13, 2011, at 4:29 AM, RDF Working Group Issue Tracker >>> wrote: >>> >>>> >>>> ISSUE-30: How does SPARQL's notion of RDF dataset relate our >>>> notion of multiple graphs? >>>> >>>> http://www.w3.org/2011/rdf-wg/track/issues/30 >>>> >>>> Raised by: On product: >>>> >>>> >>>> >>>> >>>> >>>> >>> >>> ------------------------------------------------------------ IHMC >>> (850)434 8903 or (650)494 3973 40 South Alcaniz St. >>> (850)202 4416 office Pensacola >>> (850)202 4440 fax FL 32502 >>> (850)291 0667 mobile phayesAT-SIGNihmc.us >>> http://www.ihmc.us/users/phayes >>> >>> >>> >>> >>> >>> >> > > ------------------------------------------------------------ IHMC > (850)434 8903 or (650)494 3973 40 South Alcaniz St. > (850)202 4416 office Pensacola (850)202 > 4440 fax FL 32502 (850)291 0667 > mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes > > > > > >
Received on Thursday, 14 April 2011 19:37:27 UTC