[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: XQuery and DTD/Schema?

bray xquery schema
At 09:31 AM 7/3/2002 -0700, Tim Bray wrote:
>At the moment this latter assumes that the schema validation is done by 
>XSD because as far as I can tell nobody ever asked for the ability to use 
>a different validation facility.  I see no architectural reason why you 
>couldn't add an argument or environment variable or something 
>saying  "here's the identifier of the schema language I'm using".
>It's going to be tough to tear XQuery away from XML Schema's base data 
>types, and probably not worth doing; they ain't perfect but the code to 
>deal with them is written and out there, so why fight it.  Note that XSD 
>base types are effectively built-in to RELAX software too these days.
>Beyond that, I see no architectural difficulty in making XQuery 
>schema-language agnostic.  -Tim

Making a query language agnostic with respect to the underlying model is 
fairly difficult, and the devil is in the details.

RELAX-NG uses purely structural typing. XML Schema uses named typing, as 
does XQuery (for the most part).

There is no problem supporting RELAX-NG as well-formed XML with datatypes, 
but you would have to define a mapping that creates type annotations for 
the simple types. If you want XQuery to support the structure of elements, 
you would have to create type annotations for these as well. I think all of 
this could be done, but this would require someone to sit down and do a 
fair amount of work.

There are some aspects of RELAX-NG which XQuery would not support, such as 
co-occurrence constraints.



Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
First Name
Last Name
Subscribe in XML format
RSS 2.0
Atom 0.3

Stylus Studio has published XML-DEV in RSS and ATOM formats, enabling users to easily subcribe to the list from their preferred news reader application.

Stylus Studio Sponsored Links are added links designed to provide related and additional information to the visitors of this website. they were not included by the author in the initial post. To view the content without the Sponsor Links please click here.

Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.