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As one of the early authors of this document I can provide further information (please note that I am not representing X12 in this response - this is a personal response as I am simply providing information that I hope will help clarify the observations below).
<Excerpt>
Page 53 of the PDF advises against user-defined simple
types which anyone who has used W3C XML Schema knows are very useful
(heck, didn't someone just post about needing one a few days ago[0]) and
quite straightforward to utilize.
</Excerpt>
I believe you are referring to the recommendation of "Use only XML Schema built-in data types.". What I *believe* was intended here was to recommend that W3C Schema's built-in data types (date, time, etc.) be used rather than user-defined formats, for the reasons stated under "Benefits" (interoperability and automatic validation).
<Excerpt>
Interestingly enough the X.12 Reference Model for XML Design also
prohibits using xs:appinfo elements which means that they practises like
embedding Schematron in W3C XML Schema is against their rules.
</Excerpt>
The document makes no direct assertion (pardon the pun) regarding Schematron. It simply lists the following under "Risk":
"The use of the <appinfo> element is considered highly risky at this time, due to the immaturity of XML schema processors available. There is no guarantee that a given schema processor will properly pass the processing instructions to an application, or, if it does, that an application will be able to accept them or handle them properly."
Kind Regards,
Joe Chiusano
LMI
> **************************************************************************
> Joseph M. Chiusano
> Logistics Management Institute
> 2000 Corporate Ridge
> McLean, VA 22102
> Email: jchiusano@lmi.org
> Tel: 571.633.7722
> **************************************************************************
>
-----Original Message-----
From: Dare Obasanjo [mailto:dareo@microsoft.com]
Sent: Saturday, August 31, 2002 11:36 PM
To: Rick Jelliffe; xml-dev@lists.xml.org
Subject: RE: [xml-dev] xml schema
In my personal opinion, an article that advises against using complex
types in W3C XML Schema cannot claim to be without bias. It was just
fortunate that one doesn't have to look to hard to find out why there is
bias.
As for the X.12 Reference Model for XML Design it doesn't go to as
ludicrous levels in prohibiting useful parts of the W3C XML Schema but
they still make some pronouncements that are not worthwhile advice in
the general case. Page 53 of the PDF advises against user-defined simple
types which anyone who has used W3C XML Schema knows are very useful
(heck, didn't someone just post about needing one a few days ago[0]) and
quite straightforward to utilize.
Interestingly enough the X.12 Reference Model for XML Design also
prohibits using xs:appinfo elements which means that they practises like
embedding Schematron in W3C XML Schema is against their rules. I find it
rather ironic that you are touting the document as a guideline of how to
use W3C XML Schema.
[0] http://lists.xml.org/archives/xml-dev/200208/msg01731.html
--
PITHY WORDS OF WISDOM
Old cars never die, they just smell that way.
This posting is provided "AS IS" with no warranties, and confers no
rights.
>
>
> -----Original Message-----
> From: Rick Jelliffe [mailto:ricko@allette.com.au]
> Sent: Saturday, August 31, 2002 8:15 PM
> To: xml-dev@lists.xml.org
>
> From: "Dare Obasanjo" <dareo@microsoft.com>
>
> > From the author's description at
> http://www.xml.com/pub/au/105 it is
> > noted that he is on the OASIS Technical Committee for a competing
> > schema language, RELAX NG as well as a developer for a
> RELAX NG tool.
>
> ??? He is also on the W3C XML Schema Working Group, and has
> developed an XML Schema tool too (a subset + datatypes). He
> is one of the few people in the world to have actually tried
> to implement XML Schemas (*and* RELAX NG, and TREX, and
> RELAX, and DTDs, and an experimental Schematron). Which
> would make him the most experienced implementor of different
> schema languages in the world.
>
> His article[1] is aimed at people who want to know what are
> the minimal elements they need to know about without
> sacrificing constraining power.
> And without "driving things to the limit", given that the
> wheels on a lot of WXS products are a little wonky.
>
> > I'll let you draw your own conclusions.
>
> He has worked for Sun. Some other guy works for Microsoft, who are
> competitors to Sun and have a big investment in WXS. What
> conclusions
> are we allowed to draw from that? Pfa.
>
> If we look at the X.12 Reference Model for XML Design[2] we
> see that they recommend against using the following (which
> all seem to be things that fit in with Kawaguchi-san's approach):
> * abstract types
> * substitution groups
> * redefinition
> * anonymous types
> * user-defined simple types
> * type redefinition
> * type substitution
> * no fixed or default attributes
> * chameleon schemas
>
> They go against Kawaguchi's recommendations in
> * prefer local to global
> * prefer types to groups (but they follow his approach of
> favouring a single mechanism when there are several ways to
> do something, but they choose a different mechanism)
>
> So I don't see that his views should be dismissed summarily.
> And certainly not by selectively quoting just some of his
> affiliations and proven technical expertise. Most of the
> people on the RELAX NG WG have been seminal in the XML
> specifications at W3C, and in open source software.
>
> Cheers
> Rick Jelliffe
> (Not writing on behalf of employer)
>
> [1]
> http://www.xml.com/pub/a/2001/06/06/schemasimple.html#avoid_complex
> [2]
> http://www.x12.org/x12org/comments/X12Reference_Model_For_XML_
Design.pdf
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