- From: Patrick Stickler <patrick.stickler@nokia.com>
- Date: Fri, 05 Apr 2002 06:31:04 +0300
- To: ext Graham Klyne <Graham.Klyne@mimesweeper.com>, RDF Core <w3c-rdfcore-wg@w3.org>
On 2002-04-04 22:51, "ext Graham Klyne" <Graham.Klyne@MIMEsweeper.com> wrote: > At 06:02 PM 4/4/02 +0100, Brian McBride wrote: >> RDF Schema Issues >> >> * rdfs-constraining-containers: Should it be possible to constrain >> the members of a container to be of a given type? > > I have a vague recollection we'd decided to defer this one?? (i.e. that > RDFS 1.0 would provide no such capability.) I just recieved email from an implementor, Garret Wilson at Global Mentor, that this is sorely needed for what they are doing. I encouraged him to post a summary of the issue to RDF comments. My present take on this is that we need an additional constraint property that applies to containers, such as rdfs:containerRange which would be used in conjunction with rdfs:range. We can't simply extend the semantics of rdfs:range to collections because one may wish to say that a property must take a collection, not just a single value, and thus, rdfs:range breaks. What is needed is an additional constraint mechanism, such as something like rdfs:collectionRange which would apply to the members of a collection. One would then specify e.g. that the property's rdfs:range would be rdf:Bag and the rdfs:collectionRange would be xsd:string, etc. If the rdfs:range is xsd:string, then a value of rdf:Bag is in fact a range violation since an instance of rdf:Bag is not an instance of xsd:string. Eh? Patrick -- Patrick Stickler Phone: +358 50 483 9453 Senior Research Scientist Fax: +358 7180 35409 Nokia Research Center Email: patrick.stickler@nokia.com
Received on Thursday, 4 April 2002 22:28:30 UTC