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RE: Potential TAG issue in re consistency, Schema, etc.

From: Dare Obasanjo <dareo@microsoft.com>
Date: Fri, 18 Oct 2002 08:40:16 -0700
Message-ID: <B885BEDCB3664E4AB1C72F1D85CB29F8040EF676@RED-MSG-10.redmond.corp.microsoft.com>
To: "Rick Jelliffe" <ricko@topologi.com>, <www-tag@w3.org>

Being able to represent schema components is not necessary for XQuery's needs. You are right that other schema languages could be tweaked to satisfy the same needs of XQuery. For instance, I can imagine a modified [with little change] version of XDR or a [slightly more modified] version of RELAX NG used in place of W3C XML Schema. However I do not think it is the job of the W3C XML Query working group to define the common subset of functionality in schema languages that can be used as underlying type systems for an XML query language. 
 
As for your link to the email in the member-only XQuery working group,  I am well aware of the issues raised in that email given that I was one of the people who discussed the potential problems with Michael Rys before he brought it up on that list. I believe his email states this as well. 
 

	-----Original Message----- 
	From: Rick Jelliffe [mailto:ricko@topologi.com] 
	Sent: Fri 10/18/2002 4:45 AM 
	To: www-tag@w3.org 
	Cc: 
	Subject: RE: Potential TAG issue in re consistency, Schema, etc.
	
	


	From: "Dare Obasanjo" <dareo@microsoft.com>
	
	> XPath 2.0 and XQuery use W3C XML Schema as a basis for a type system and
	> not merely as a validation language.
	
	But XQuery has its own data model and  "The data model does not represent element
	or attribute declaration schema components, but it supports various type-related
	operations." [1]  
	
	The distinctive feature of WXS is not the type lattice in a resulting type-augmented
	infoset (other schema languages could be invented to provide that, if there were
	a reason) as much as its specific components: elements, abstract types,
	substitution groups, etc.
	
	(And, for the an interesting disconnect between XQuery and WXS, see also
	http://lists.w3.org/Archives/Member/w3c-xml-query-wg/2002Oct/0317.html)
	
	
	Cheers
	Rick Jelliffe
	
	[1] http://www.w3.org/TR/query-datamodel/#types
	
	
Received on Friday, 18 October 2002 11:40:48 GMT

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