- From: Dan Brickley <danbri@w3.org>
- Date: Mon, 17 Jan 2005 05:46:27 -0500
- To: public-rdf-dawg-comments@w3.org
Peeking at http://www.w3.org/2001/sw/DataAccess/rq23/ "10.3.2 Identifying Resources" I see evidence of an assumption that the data we're querying will be a true description of the world, or at least not self-evidently contradictory. The property foaf:mbox is defined as being an inverse function property in the FOAF vocabulary so that this query will retrun information about at most one person. Since we don't (do we?) assume DAWG services will all be OWL-capable, I can imagine scenarios where this paragraph doesn't hold. I'm interested in the thinking behind the 'so' --- is some form of OWL reasoning being assumed? is good/clean/tidy/true data being assumed? Is SPARQL supposed to be usable against both OWL-smart and OWL-ignorant systems? (typo btw, s/retrun/return; sorry, I realise this is an editor's draft, but I think my question general enough to be worth sending). The dataset could (inaccurately, but most databases contain errors) associate the same foaf:mbox value with several different people and their descriptions. And some datasets might very usefully contain false claims... http://rdfweb.org/people/danbri/2001/12/puzzle/unicorny.html is an example (confusing; Unicorn was a bad example) of doing so for the purposes of image annotation --- ie. an RDF graph might describe the scene depicted in some work. Family tree (eg. gedcom) and other historical datasets are another obvious example, as are any where we care to track the source/provenance of our possibly flawed data (foafcorp info about companies being my favourite usecase here). SPARQL's 'source' facilities make such applications pretty likely. I don't have a rewording suggestion for the text I quote above as I don't know what the WG's design is. One other Editorial/wording comment, for 10.3.2 in the editor's copy, http://www.w3.org/2001/sw/DataAccess/rq23/ "This enables resources which are bNodes to be identified" ...perhaps confuses the thing in the world with the thing in the RDF graph that stands for it. This btw is why RDFCore introduced the term "bNode" in preference to the previously-widespread "anonymous resource". Resources aren't intrinsically anonymous or blank; they might be URI-labelled or not in the possibly various RDF graphs which mention them. While we could argue bNodes, ie. bits of RDF graphs, are also things/resources, I expect the intent is not this, and we're talking about identification of the thing the bNode stands for. I Suggest something like: "This enables (indirect) identification of resources, regardless of whether they are labelled with a URI in the graph(s) being queried." cheers, Dan ps. I'm likely to propose you drop 10.3/DESCRIBE entirely, so don't kill yourselves wordsmithing... ;) <ducks/>
Received on Monday, 17 January 2005 10:46:28 UTC