Re: Ways to restrict the properties a class may have?

From: Jan Algermissen <jalgermissen@topicmapping.com>
Subject: Re: Ways to restrict the properties a class may have?
Date: Fri, 29 Oct 2004 16:12:48 +0200

> 
> Chris Purcell wrote:
> > 
> > > OTH, checking that an employee cannot have a numberOfWindows property
> > > is not a bad thing after all :-)
> > 
> > [ex:numberOfWindows rdfs:domain ex:somethingWithWindows]
> > [ex:somethingWithWindows owl:disjointWith ex:employee]
> > 
> > Is that reasonable?
> 
> Hmm...not really. My point is that I want to develop a system that loads the
> constraints and rejects 'broken' updates. This is just like RDBMSs keep data
> from becoming 'incorrect' (according to the constraints). I want to avoid
> having to develop extra checking code.

Huh?  Why would a system that checks to see if an inconsistency results
from a update and rejects such updates not satisfy your requirements?

For example, 

ex:numberOfWindows rdfs:domain ex:somethingWithWindows .
ex:somethingWithWindows owl:disjointWith ex:employee .

ex:Jan rdf:type ex:employee .

ex:Jan numberOfWindows "5"^^xsd:int .

is inconsistent (in OWL) and an OWL reasoner can detect this.

> Basically, I want business rules (aka constraints) expressed as RDF.

Again, I don't understand what is lacking.

> I could of course develop my own vocabulary for this, but something
> standardized would be better.
> 
> Thanks anyway,
> 
> Jan

Peter F. Patel-Schneider
Bell Labs Research