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Re: XML Schema: DOs and DON'Ts

From: Jeff Rafter <jeffrafter@---------.--->
To: Kohsuke KAWAGUCHI <kohsukekawaguchi@-----.--->
Date: 5/21/2001 3:19:00 PM
First off let me say thanks for writing up this document-- while I don't
agree with several parts I find it very informative and useful--

> > But my point is that when you use attribute groups you *are* using local
> > attribute declarations. The attribute
> Right. But I want readers to understand that <attribute> is allowed only
> under an <attributeGroup>, just like DTD.  People don't need to learn
> another way to do the same thing. One is enough.

One of the biggest issues I am struggling to understand is your rationale
against local attribute declarations.  It seems to be 100% in contrast to
your rationale against global complexTypes.  In global complexTypes the only
additional learning is how to refer to them-- which seems to correspond with
the additional reference to an attributeGroup.  While I am happy to see
attributeGroup survive the simplicity surgery, I think it is at odds with
the basic nature of your document.  As far as "learning another way to do
the same thing" I disagree.  You would be learning less if attributeGroup
were excluded in favor of local attributeDeclarations to begin with.  It is
simply a matter of placement of the attribute declaration-- which is easier
than understanding the attributeGroup syntax.  Granted if you recommended
only using local attribute declarations you would lose some significant
features-- but isn't that the purpose of the document?

IMHO I think that attributeGroup is not on the first level of simplicity--
it is on the second, with global complex types.  Somewhere on the third
level of simplicity/difficulty is type-substitution and inheritence.  The
fourth level is reserved for qualified/unqualified and importing/redifining.

It seems a reformulation of the document based on levels of difficulty
regardless of feature loss might hit your target audience a little better.

All of that said, I do like the document-- keep up the good work.

Jeff Rafter
Defined Systems
XML Development and Developer Web Hosting


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