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[Bug 8913] New: Rec 1.1 authorizes schemas not to be valid schemas

From: <bugzilla@wiggum.w3.org>
Date: Wed, 10 Feb 2010 06:46:34 +0000
To: www-xml-schema-comments@w3.org
Message-ID: <bug-8913-703@http.www.w3.org/Bugs/Public/>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=8913

           Summary: Rec 1.1 authorizes schemas not to be valid schemas
           Product: XML Schema
           Version: 1.1 only
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: externalComments
          Severity: major
          Priority: P2
         Component: Structures: XSD Part 1
        AssignedTo: David_E3@VERIFONE.com
        ReportedBy: jjthomasson@free.fr
         QAContact: www-xml-schema-comments@w3.org
                CC: cmsmcq@blackmesatech.com, jjthomasson@free.fr


Dear members of the XSD 1.1 working group

In the text of recommendation 1.1, the rules number :

- 1.1 and 1.2 of section 4.2.3
- 2.1 and 2.2 of section 4.2.4

have been changed so that an included or redefined <schema> could now be not a
conforming schema.

By doing this, it appears that one same root element "xs:schema" could
introduce both a simple "well formed XML document" and a conforming XML Schema.
I'm afraid that it is :
1) introducing confusions about what is a schema and what is not.
2) transforming the original pure XML Schema logic into the traditional DTD
approach where physical chunking could led to bad management of elements
definitions.

The original strict logic of XSD has helped some working groups to clarify the
design of complex models, to rationalize the writing of those models and the
organization of the sets of elements and attributes.
You will find enclosed the presentation I did about the problem of physical
chunking to the ASD/S1000D/EPWG (the Electronic Publication Working Group of
the Association of the Aerospace and Defence Industry) at Clearwater (Florida)
in 2005.

If a physical chunking is necessary for the migration of some past models based
on DTDs, then I suggest that a clear new element is used instead of <xs:schema>
and clear new statements are used instead of <xs:include/import/redefine>. At
least to avoid confusion between the past and this new approach and help the
designers to choose between one or the other approach.

About the new <xs:override> mechanism, I would also like to highlight the fact
that the need for such a feature could be the result of some past DTD
mechanisms (of course the SYSTEM ENTITY one). In terms of data modeling, I
consider that it does not help at designing pure XML "hierarchical" models.

Those changes in the specification dramatically change the phylosophy and logic
of XML Schema and one question arises : Should XML Schema mimics the DTDS ? Do
we really need a 100% functional compatibility between DTDs, XML Schema and
Relax NG ? and also Schematron ?

Yours sincerely and I apologize if you condiser that my vision and comment are
stupid.

Jean-Jacques Thomasson
French translator of XML Schema Part 0 and 1.
French translator of O'Reilly book "XML Schema".
Author of "Schémas XML" (2002) and "Modélisation XML" (2006) at Eyrolles
publishing house.


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Received on Wednesday, 10 February 2010 06:46:36 GMT

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