- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Wed, 22 Dec 2004 18:35:54 +0000
- To: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
- Cc: DAWG public list <public-rdf-dawg@w3.org>
Steve Harris wrote: > On Wed, Dec 22, 2004 at 05:49:00PM +0000, Andy Seaborne wrote: > >>Steve Harris wrote: >> >>>Here one of mine [sorry for the lateness] >> >>I'm having to catch up :-( >> >> >>>A user wanted to get a list of papers from our computer science research >>>KB, but he only wanted ones that probably weren't processed by some >>>heuristics based nataural language software, so hte query (in DAWG speak) >>>was: >>> >>> SELECT ?id ?title >>> WHERE SOURCE ?src (?id dc:title ?title) >>> (?src dc:creator ?creator) >>> AND ?creator !~ /^Armadillo/ >>> >>>assuming a direct relation between the SOURCE node and the document URI, >>>and >>> >>> SELECT ?id ?title >>> WHERE SOURCE ?src (?id dc:title ?title) >>> (?src dawg:source ?doc) >>> (?doc dc:creator ?creator) >>> AND ?creator !~ /^Armadillo/ >>> >>>if not. s/dawg:source/dc:source/ if you prefer >> >>Both queries are legal. Just depends what you decide to put in the default >>KB. You can model your provenance how you like. >> >>In either design, ?src is a URI (otherwise you can't put it in a graph) - >>bNodes also work apart from GRAPH declarations (which 3Store wouldn't use) >>but ?src as a graph does not. >> >>Collapsing dawg:source (i.e. design 1) is a matter of do you want to record >>other information gainst ?doc that is not true of ?src. As ever, a more >>detailed modelling gets inconvenient in general use. returning ?src (some >>pre-read-in-doc) URI is not going to be what apps usually want. Unless >>they are the data maintenance app, of course! > > > Yes, exactly. The problem with collapsing is that it rules out that class > of data-maintainance task. I agree its somewhat inconvient though, as the > 2 queries show. > > In defense of the dawg:source style, systems that dont care about > historical provenance can just assert (<uri> dawg:source <uri>) and get on > with it. > > I could live with a collapsed form though, You don't have to! You-the-DB-designer can choose. It isn't a WG decision. That's what I meant by both are legal. Andy > I will just have to provide > some API mechanism to indirect at asserion time for people who need the > extra level. Which is more or less what I do now, you can specify a graph > URI (or request a bnode) that is distinct from the resolved URI. > > - Steve >
Received on Wednesday, 22 December 2004 18:36:26 UTC