- From: Gregory Williams <greg@evilfunhouse.com>
- Date: Mon, 7 Feb 2011 15:22:09 -0500
- To: Chimezie Ogbuji <chimezie@gmail.com>
- Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
On Feb 7, 2011, at 2:32 PM, Chimezie Ogbuji wrote: > On Sun, Feb 6, 2011 at 5:30 PM, Andy Seaborne > <andy.seaborne@epimorphics.com> wrote: >>> returns >>> @prefix rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> . >>> @prefix sd:<http://www.w3.org/ns/sparql-service-description#> . >>> [] a sd:Service; >>> sd:defaultDatasetDescription<http://host/graphstore> >>> <http://host/graphstore> a sd:Dataset; ..snip.. > >> But this says: >> >> http://host/graphstore a sd:Dataset ; >> and >> >> [] a sd:Service; >> >> which is odd to return from Dataset HTTP Protocol service > > Yes. I guess that suggests (if we are using the SD vocabulary for > this purpose) we should expect the URLs of the sd:Service instance > (when retrieved from a Dataset HTTP protocol instance) to be used. On > that related note, I noticed the SD vocabulary has an sd:url property > with a domain of sd:Service and a range of a URI reference. How is > this different from the URI of the sd:Service instance itself? I.e., > this seems redundant: > > <http://example.com/dataset-service> a sd:Service; > sd:uri "http://example.com/dataset-service"^^xsd:anyURI Oh dear. The SD document seems to have slipped into some confusion here. My recollection is that the modeling: [] a sd:Service ; sd:url </sparql> was done because there's not always a one to one relationship between service and endpoint url. Doing the modeling as </sparql> a sd:Service means that to support situations where a service is accessible through several URLs means the SD must either duplicate a lot of the triples or support sameAs reasoning. The example RDF in the SD document uses the first modeling pattern in which the service is a blank node with a sd:url with the endpoint url. However, I realize I confused the issue with the recent addition of the conformance section that claims to require a triple of the form: <service-URL> rdf:type sd:Service > In the way you think about the service and the graph store, what is > the relationship between them? Is it one-to-one? i.e.: > > sd:defaultDatasetDescription a owl:FunctionalProperty I agree with this. I can add this to the SD vocab if there's agreement. > I think of it as a functional relationship. From the REST view-point, > however, I think of it in this way (using the vocabulary from my > earlier email on this thread and from "HTTP semantics in OWL" [1]): > > @prefix tag: <http://w3.org/2001/tag/awwsw/http#>. > sd:manages > a owl:FunctionalProperty; > rdfs:subPropertyOf sd:defaultDatasetDescription; > rdfs:domain sd:RESTDatasetService; > rdfs:range GraphStore Are you suggesting adding this to the SD vocab? > GraphStore owl:intersectionOf ( sd:DataSet tag:Get200WildRdfSubject > MutableWebResource ) I don't know what tag:Get200WildRdfSubject is, nor how MutableWebResource might be represented. .greg
Received on Monday, 7 February 2011 20:22:43 UTC