- From: Ian Horrocks <horrocks@cs.man.ac.uk>
- Date: Thu, 2 May 2002 21:27:45 +0100
- To: Dan Connolly <connolly@w3.org>
- Cc: Ziv Hellman <ziv@unicorn.com>, www-webont-wg@w3.org
On May 2, Dan Connolly writes: > On Thu, 2002-05-02 at 12:46, Ziv Hellman wrote: > > I was recently looking through some DAML+OIL documentation and I noticed > > that in order to, for example, constrain the property 'age' of a class > > Adult to being 17 or over, one needs the following syntax. > > > > <daml:Class rdf:ID="Adult"> > > <daml:intersectionOf rdf:parseType="daml:collection"> > > <daml:Class rdf:about="#Person"/> > > <daml:Restriction> > > <daml:onProperty rdf:resource="#age"/> > > <daml:hasClass > > > > rdf:resource="http://www.daml.org/2001/03/daml+oil-ex-dt#over17"/> > > </daml:Restriction> > > </daml:intersectionOf> > > </daml:Class> > > > > <xsd:simpleType name="over17"> > > <!-- over17 is an XMLS datatype based on decimal --> > > <!-- with the added restriction that values must be >= 17 --> > > <xsd:restriction base="xsd:decimal"> > > <xsd:minInclusive value="17"/> > > </xsd:restriction> > > </xsd:simpleType> > > In the course of the design of DAML+OIL, I suggested incorporating > XML Schema datatype facets into RDF/DAML+OIL; it might look > like this... > > <rdf:RDF > xmlns:dt="http://www.w3.org/2001/XMLSchema#" > xmlns:ex="http://example/vocab#" > xmlns:ont="http://www.daml.org/2001/03/daml+oil#" > xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" > xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"> > > <rdfs:Class rdf:about="http://example/vocab#Adult"> > <ont:intersectionOf rdf:parseType="ont:collection"> > <rdfs:Class rdf:about="http://example/vocab#Person"/> > <ont:Restriction> > <ont:hasClass rdf:parseType="Resource"> > <ont:intersectionOf rdf:parseType="ont:collection"> > <rdfs:Class > rdf:resource="http://www.w3.org/2001/XMLSchema#decimal"/> > <rdfs:Class> > <dt:minInclusive>17</dt:minInclusive> > </rdfs:Class> > </ont:intersectionOf> > </ont:hasClass> > <ont:onProperty rdf:resource="http://example/vocab#age"/> > </ont:Restriction> > </ont:intersectionOf> > </rdfs:Class> > </rdf:RDF> > > or something like that. > > But the group decided to keep the datatypes and the rest of the universe > of discourse separate, and this was one of the related consequences. Syntax and semantics are separate issues and completely orthogonal in this case: we could keep the current syntax but change the semantics to have a single universe OR change the syntax to some "in-line" format without changing the semantics OR change both (OR change neither). Ian > > I have raised the issue of splitting datatypes out... > http://www.w3.org/2001/sw/WebOnt/webont-issues.html#5.1-Uniform-treatment-of-literal/data-values > > But maybe this is worth a separate issue. > > In the RDF Core WG's discussions about datatypes, I recently > suggested we include facets in the design... > > # user-defined datatype (facet) support needed? > Dan Connolly (Tue, Apr 30 2002) > http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Apr/0547.html > > > > [...] > > Will OWL inherit this type of behaviout from DAML+OIL? > > Unless somebody raises an issue and we decide to resolve > the issue by changing it, yes. > > -- > Dan Connolly, W3C http://www.w3.org/People/Connolly/ >
Received on Thursday, 2 May 2002 16:31:00 UTC