- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Mon, 18 Apr 2011 20:08:47 +0100
- To: public-rdf-wg@w3.org
Dan, Good example. There are various ways the SPARQL dataset notion can be used. IRI for each g-snap of the same g-box is certainly one of them. The whole concept of RDF datasets was a recognition that quad usage existed. "RDF dataset" is a compromise from various existing practices, from systems using the word "context" (usually collection of triples as subset of the graph) to multi-graph usages as you describe and variations in between. On 18/04/11 15:27, Dan Brickley wrote: > [snip] > > Let me offer a practical use case: the evolving RDF graphs served from > FOAF and Dublin Core namespace URIs. > > For the FOAF case xmlns="http://xmlns.com/foaf/0.1/", the RDF > available (via conneg, link rel or sometimes embedded in HTML) can be > found in our Subversion server at > http://svn.foaf-project.org/foaf/trunk/xmlns.com/htdocs/foaf/0.1/index.rdf > ... you can fetch any version going back to ~2002 via public SVN. > > For the Dublin Core case, xmlns="http://purl.org/dc/elements/1.1/" and > others nearby are documented in http://dublincore.org/schemas/rdfs/ > including links to each version of the schema file, and with > social/process documentation of those changes at > http://dublincore.org/usage/terms/history/ > > Consider a SPARQL service devoted to keeping record of what key > namespaces have said about themselves over the years. They could take > each of these snapshot RDF files and put the corresponding triples in > a different named graph. (Maybe we should prepare N-Quads/Trig dumps > of the data for testing?). and reserve the N-Quads and Trig as a syntax for RDF datasets. If there is to be a syntax form for a different notion, then keep them apart (based on graph literals a la N3?). > We should be able to queries such as "when did foaf:givenName change > from Unstable status" or "when did DCMI begin to mention dc:audience > ?". If we use the URI we 'GET'd for the graph name, these sort of > historically minded queries won't be possible as the graphs will get > mixed up. > > All this talk of HTTP response codes is great and nice and practical, > ... so long as we're crystal clear that the Web gives back different > things over time, and often we'll want to be explicit about that. > Eventually we'll also want to be a bit more clear about security > properties, such as which copies of a schema check out as having been > signed by such-and-so key. > > cheers, > > Dan > > ps. for the foaf case, revisions are available via: svn log > http://svn.foaf-project.org/foaf/trunk/xmlns.com/htdocs/foaf/0.1/index.rdf > ...then you can pull them (per directory) eg. with: svn co -r r186 > http://svn.foaf-project.org/foaf/trunk/xmlns.com/htdocs/foaf/0.1/ ... > so you can see that > <http://xmlns.com/foaf/0.1/homepage> > <http://www.w3.org/2000/01/rdf-schema#domain> > <http://xmlns.com/foaf/0.1/Person> . > ...used to be in there, before we broadened it. Question to my mind > is, how do we elevate the tooling so you can find this out using > SPARQL and RDF instead of SVN and grep? >
Received on Monday, 18 April 2011 19:09:19 UTC