- From: Patrick Stickler <patrick.stickler@nokia.com>
- Date: Thu, 20 Nov 2003 13:37:44 +0200
- To: "ext Pete Johnston" <p.johnston@ukoln.ac.uk>
- Cc: www-rdf-interest@w3.org
Thanks, Pete, for touching on this issue. I had held back, figuring folks were tired of that particular "soap box" of mine ;-) For those interested in modelling vocabularies in RDF, have a look at http://sw.nokia.com/schemas/general/VOC-1.0.rdf or in browsable form http://sw.nokia.com/uriqa?uri=http://sw.nokia.com/VOC-1&format=text/html and to see how VOC supports the hierarchical organization of vocabularies and subvocabularies with terms selected from arbitrary namespaces, have a look at http://sw.nokia.com/schemas/nokia/FN-1.0.rdf or in browsable form http://sw.nokia.com/uriqa?uri=http://sw.nokia.com/FN-1&format=text/html I guess the VOC schema would be a candidate for SchemaWeb... ;-) Cheers, Patrick On Wednesday, Nov 19, 2003, at 16:29 Europe/Helsinki, ext Pete Johnston wrote: > > Victor Lindesay said: > >> SchemaWeb is at: >> http://www.schemaweb.info/ >> Your feedback is welcome. > > Thanks for this. It is very nice indeed, and a very useful service. > > Apologies if this seems like nit-picking, but I have one query in that > the display of metadata about a schema displays an entry "namespace", > and I'm not quite clear what "namespace" means in this context. Is it > the XML Namespace Name typically used in RDF/XML? Or is it used as a > synonym for "vocabulary"? > > Anyway the data available suggests to me that there is a one-to-one > correspondence between a schema and a "namespace". > > Patrick Stickler argued long and hard (and to me, at least, > convincingly) on this list, see e.g. > > http://lists.w3.org/Archives/Public/www-rdf-interest/2002Jun/0016.html > > and elsewhere that namespaces-as-XML-Namespaces are simply part of the > "punctuation" of the RDF/XML serialisation of RDF, and that there is no > necessary one-to-one correspondence between: > > - what the RDF specs call a vocabulary (a set of URIrefs) (I think > there > was an RDF Core decision to use the term "vocabulary" rather than > "namespace" for this purpose precisely in order to avoid any confusion > with XML Namespaces), > - a schema (an RDF/XML document providing info about the resources > denoted by those URIrefs), and > - an XML Namespace. > > It _may_ be that for all my classes and properties with URIrefs > beginning http://example.org/ns/, I create RDFS descriptions in one > RDF/XML document which I make available at that URL, but there is no > _requirement_ that that is the case. > > In fact one of the examples indexed by the registry highlights this. > The > metadata for the schema for the RDFS vocabulary > > http://www.schemaweb.info/schema/SchemaDetails.aspx?id=2 > > says > > Namespace: http://www.w3.org/2000/01/rdf-schema# > > But if you click on "classes and properties", you see that the data > provided in the schema currently located at > > http://www.w3.org/TR/rdf-schema/rdfs-namespace.xml > > does (quite reasonably) include descriptions of resources such as > http://www.w3.org/1999/02/22-rdf-syntax-ns#type etc - terms "from > another namespace", if you like, which of course are also described by > the schema located at > > http://www.w3.org/1999/02/22-rdf-syntax-ns > > and described by > > http://www.schemaweb.info/schema/SchemaDetails.aspx?id=1 > > So I think I'm wondering whether describing a relationship between a > schema and an XML Namespace is perhaps inappropriate; and while the > relationship between schema and vocabulary (if that is what is intended > by "Namespace" in this case rather than XML Namespace) may be worth > describing, it is potentially many to many, as this example suggests? > > Cheers > > Pete >
Received on Thursday, 20 November 2003 06:42:39 UTC