W3C home > Mailing lists > Public > www-tag@w3.org > February 2002

RE: [namespaceDocument-8] 14 Theses, take 2

From: Graham Klyne <GK@ninebynine.org>
Date: Tue, 19 Feb 2002 11:24:26 +0000
Message-Id: <>
To: "David Orchard" <david.orchard@bea.com>
Cc: "'TAG'" <www-tag@w3.org>
I think this pinhead-angel-counting has an important purpose beyond arguing 
about the meaning of "schema", viz that one might reasonably want to use a 
namespace URI to associate both syntactic and interpretive definitional 
material with a document.  I take that to be the substantive point behind 
the discussion so far.


At 02:29 PM 2/18/02 -0800, David Orchard wrote:
>This is starting to get discouraging.  I find it amazing that the TAG cannot
>get to consensus on what a schema is, even though it is used in different
>specifications at the W3C and the W3C even has an XML Schema language.
>I believe we must solve this definition problem and document this in our
>arch document.  We obviously have 2 camps:
>1) schemas are syntactic validation, and dtds/xml schema/relax/dcd/WSDL are
>2) schemas are any kind of definition used in interpretation.  This includes
>1) but adds in html, RDF Schema, others.  A fragment from RDF Schema
>illustrates "Unlike an XML DTD or Schema, which gives specific constraints
>on the structure of an XML document, an RDF Schema provides information
>about the interpretation of the statements given in an RDF data model. "
>For point of information, I did a quick survey internally and every single
>developer that I talked in my company found option #1 to be correct, and
>option #2 to be a non-helpful definition.  The re-inforcement of this
>position was pointed out in the very name of "XML Schema", which talks about
>syntactic constraints.  A developer asked about the difference between
>definition #2 of schema and the term metadata, to which I didn't have an
>answer.  I venture that every developer in my company and probably almost
>all of our > 10 000 customers consider #1 to be the correct definition.
>I briefly thought that we could define 2 sub-types of schema languages,
>something like: syntactic schema and interpretive/semantic/? schema.  I also
>ran this separation by our developers.  The response was one of disbelief
>that the TAG was even spending time on this when the "real" answer was so
>obvious and one developer joked about counting angels on pin heads.  All
>this reaffirmed my earlier position on the definition of schema.
>Is there any possibility that the proponents of option #2 could see their
>way to adopting schema definition #1?  I would volunteer to help with coming
>up with a new term for #2.
>Maybe I'm being naive that we can make progress on this, but it seems
>important to be precise and also obey the least-astonishment rule.
> > -----Original Message-----
> > From: www-tag-request@w3.org
> > [mailto:www-tag-request@w3.org]On Behalf Of
> > Tim Bray
> > Sent: Monday, February 18, 2002 1:51 PM
> > To: TAG
> > Subject: [namespaceDocument-8] 14 Theses, take 2
> >
> >
> > During the TAG telecon this morning, there was some discussion
> > of my theses on namespace documents.  Someone made the wild claim
> > that there was consensus on most points, which to be fair seems
> > a little unlikely since they had been published for considerably
> > less than 12 hours at the time.
> >
> > Having said that, Paul Cotton had an issue with thesis 7 "Definitive
> > material is normally distributed among multiple resources", offering
> > the counter-example of "lightweight" namespaces he and colleagues
> > routinely cook up for a list of words or the functions in an API
> > or something, that typically only come with a chunk of text.
> > Seems fair; I redrafted section 7 to acknowledge this case.  [I
> > don't think it weakens the arguments for any of the following theses].
> >
> > Several people had trouble with thesis 14 "Namespace documents
> > should not be schemas"; mostly it seemed, based on lack of agreement
> > as to what a schema is or should be.  I've redrafted that one to
> > make it clear that we're talking about the mostly-syntactic schemas
> > of today (e.g. DTDs, XML Schemas), what the world calls schemas
> > today - and put the word "schemas" in quotes in the thesis statement.
> >
> > Finally, Dan Connolly had an issue with Thesis 13 "Namespace
> > documents should not favor the needs of any one application or
> > application class" which I never got time to understand. Dan?
> >  -Tim
> >
> >

Graham Klyne
Received on Tuesday, 19 February 2002 06:56:21 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 7 January 2015 15:32:30 UTC