- From: Eric Hellman <eric@openly.com>
- Date: Fri, 31 Dec 1999 12:33:36 -0500
- To: Gabe Beged-Dov <begeddov@jfinity.com>, Jeff Sussna <jeff.sussna@quokka.com>
- Cc: "'www-rdf-interest@w3.org'" <www-rdf-interest@w3.org>
I agree this is confusing, it was referred to in an earlier discussion as "striping" of syntax. Implicit in the RDF syntax is the notion that something is either a property or a value. The parseType="Resource" attribute leads to confusion because it implies the creation of an anonymous resource. Having both rdf:ID and RDF:resource attributes is illegal because the parser can't decide whether it's a value or a property. Another way to look at this is to asK if you have > <playsFor rdf:ID="44" rdf:resource="Pirates"/> then what does the ID identify? the statement, or the resource? I agree it would be convenient to have a separate ID for the reification, but perhaps that's nasty. Presented with a similar problem to Jeff Sussna's, we explicitly made an intermediate object. so Mick has sponsorship x (x is a Sponsorship object) x has startyear 1985 x has stopyear 1990 x has sponsorname pennzoil So because RDF is property-oriented, we end up creating lots of objects. At 3:40 PM -0800 12/30/99, Gabe Beged-Dov wrote: >Jeff Sussna wrote: > > > > Given the notion of reification, it would be nice to be able to simply say > > "property X defined within description Y has the timeframe 1987-1993". As > > far as I can tell, however, this is impossible, since there is no way to > > make a statement about a single member of a container (the >contained in this > > case being the Bag of property statements contained by the description). > >Taken from the formal grammar section of the spec: > > Within propertyElt (production [6.12]), the URI used >in > a resource attribute identifies (after resolution) > the resource that is the object of the statement >(i.e., > the value of this property). The value of the ID > attribute, if specified, is the identifier for the > resource that represents the reification of the > statement. > >Note the second sentence. I don't think that this >information is maintained by current parsers but it >does allow you to identify the reification of a >specific statement in a description. > >If it was supported, you could say: > ><rdf:Description about="Jimmy"> > <playsFor rdf:ID="44" rdf:resource="Pirates"/> > <playsFor rdf:ID="55" rdf:resource="Brigands"/> ></rdf:Description> > ><rdf:Description about="#44"> > <startDate>2/3/78</startDate> > <endDate>2/2/81</endDate> ></rdf:Description> > ><rdf:Description about="#55"> > <startDate>2/3/81</startDate> > <endDate>2/2/83</endDate> ></rdf:Description> > >Cordially from Corvallis, > >Gabe Beged-Dov Eric Hellman Openly Informatics, Inc. http://www.openly.com/ 21st Century Information Infrastructure
Received on Friday, 31 December 1999 12:34:01 UTC