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

From: David Orchard <david.orchard@bea.com>
Date: Mon, 18 Feb 2002 14:29:28 -0800
To: "'TAG'" <www-tag@w3.org>
Message-ID: <004801c1b8cb$bb355130$0100007f@beasys.com>
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
Received on Monday, 18 February 2002 17:34:07 UTC

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