xml-dev - Re: Schemata are not just constraints [was: "RDF + Topic Maps" =TheFutur

[Jonathan Borden <jborden@mediaone.net>]

Thomas B. Passin wrote:

> Martin Bryan wrote in part -
>
> The problem is that
> > neither RDF or Topic Maps have a requirement of the supply of any
> > human-readable descripition of the meaning of any referenced subject.
> >
> This is one of the reasons that I strongly disagree with requirements, for
> either RDF or Topic Maps, that subjects (or their equivalents) have to be
urns
> or some kind of address.   They ought to be able to just be data (like
> strings). If you want machine-readable terms for inference or
hyperlinking,
> fine, use them.  If you want text phrases for humans to read on a display,
use
> strings ( or data: urns).  Don't restrict the map creator.


    There is no restriction on the values of properties in RDF being URIs,
they may be either URIs (of rdf:type rdf:Resource) or string literals
(rdf:type rdf:Literal), so this restriction on the values of properties does
not exist. The subject is intended to be an addressable node hence a
resource, the object may be either a resource or literal. This places no
limits on the type of information which can be represented in RDF (beyond
what can be represented in XML itself).

    Your complain is directly akin to complaining that the tag name of an
element is restricted to a QName and may not be an arbitrary human readable
string. That's just how it is, yet we are able to do stuff with XML
nonetheless.

Jonathan Borden
The Open Healthcare Group
http://www.openhealth.org