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RE: XML Schema Design Patterns: Avoiding Complexity

From: Dare Obasanjo <dareo@microsoft.com>
Date: Sat, 23 Nov 2002 13:38:52 -0800
Message-ID: <B885BEDCB3664E4AB1C72F1D85CB29F8040EF7DA@RED-MSG-10.redmond.corp.microsoft.com>
To: "Dan Vint" <dvint@mindspring.com>, <xmlschema-dev@w3.org>

The guidelines were meant for schema authors and were not influenced by implementations except for the part about complex type restrictions which was influenced by both. 

	-----Original Message----- 
	From: Dan Vint [mailto:dvint@mindspring.com] 
	Sent: Thu 11/21/2002 9:45 AM 
	To: xmlschema-dev@w3.org 
	Cc: 
	Subject: Re: XML Schema Design Patterns: Avoiding Complexity
	
	


	Interesting set of Do's and Don'ts. I see several items listed as implement
	carefully. Has this set only been considered as individual items, or have
	they also been evaluated in the context of having a schema that uses all of
	them.
	
	Seems to me that you might easily work with one or two of the "careful"
	items and still have a manageable schema, but try and use all the
	recommendations together and the complexity returns.
	
	I didn't see a statement of whose complexity we are considering - is it the
	tools and parsers or complexity in terms of the human trying to implement?
	For instance I have had problems with complexType definitions that are
	fairly easy to follow by hand, but when these are nested several tools
	loose the ability to detect duplicate attribute declarations that occur due
	to inheritance. This would be a type based upon another type nested 3
	layers deep.
	
	The use of substitution groups are impossible to try and manage by hand in
	a schema over 20 elements in size, but maybe is easy for the parser to deal
	with. We haven't used these much so I don't know how well the tools support
	this (or report what elements would now be allowed that you might not be
	thinking of).
	
	..dan
	
	At 07:19 PM 11/20/2002 -0800, Dare Obasanjo wrote:
	
	>http://www.xml.com/pub/a/2002/11/20/schemas.html
	>
	>The above link is to an article just published on XML.com on working with
	>W3C XML Schema which is part guidelines on how best to use the language
	>while avoiding getting bogged down in the complex bits and part response
	>to Koshuke Kawaguchi's article at
	>http://www.xml.com/pub/a/2001/06/06/schemasimple.html
	
	
Received on Saturday, 23 November 2002 16:39:25 GMT

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