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Re: datatypes: conversation with Mark Butler, chair of cc/pp

From: int Patrick Stickler <patrick.stickler@nokia.com>
Date: Thu, 15 Aug 2002 09:17:15 +0300
To: "RDF Core" <w3c-rdfcore-wg@w3.org>, "ext Brian McBride" <bwm@hplb.hpl.hp.com>
Cc: mark_butler@otter.hpl.hp.com
Message-ID: <NYcVPGYxCBVp.HhDjXNXL@mail.nokia.com>

I have also myself been having discussions with some of
my collegues about validation of cc/pp instances, but don't
consider it necessary to marry XML Schema and RDF in
order to do so.

Firstly, since cc/pp uses implicit, global datatyping, with
the inline idiom, one can define an XML Schema which
constrains the property elements to the particular
datatypes. No xsi:type is needed to validate.

Secondly, for RDF applications, one can specify the
analog of the XML Schema property element type
definitions with rdfs:range definitions. It also would
be straightforward to autogenerate an XML Schema
for lexical form validation directly from the RDF
knowledge about property range constraints. Thus,
rather than infusing XML Schema machinery into
the RDF/XML, one would derive an XML Scema
from the RDF.

Thirdly, I think it is important to keep clear the fact
that, even though RDF employs XML and thus its
serialization falls within the scope of XML Schema,
(1) RDF is not XML nor is it an extension of XML
Schema, (2) RDF can fully support datatyping using
XML Schema datatypes without recourse to XML
Schema machinery, and (3) even though both RDF
and XML Schema are both "children" of the W3C,
creating interdependencies between them, or any
standards, should be done only when absolutely
necessary or if there is overwhelming benefit. I don't
see either justification in this case.

So, I don't see the cc/pp validation needs as 
sufficient reason for the adoption of xsi:type
or the XML Schema'zation of RDF/XML.


_____________Original message ____________
Subject:	datatypes: conversation with Mark Butler, chair of cc/pp
Sender:	ext Brian McBride <bwm@hplb.hpl.hp.com>
Date:		Thu, 15 Aug 2002 08:56:48 +0300

I chatted with Mark Butler yesterday, including some discussion of 
datatypes in cc/pp.

One of the ideas that Mark favours is to define an XML Schema for the cc/pp 
language.  This would enable:

   o validation of incoming cc/pp profiles to a server
   o the use of default attributes to insert datatype attributes such as 
xsi:type="xsd:decimal" automatically, thus providing global implicit 
datatyping in the parser.

Whilst not perfect, does this technique go some way towards meeting the 
need for global implicit datatyping.

Received on Thursday, 15 August 2002 02:18:20 UTC

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