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Re: 3rd try on versioning question

From: Anthony B. Coates <abcoates@idmm.co.uk>
Date: Mon, 18 Oct 2004 21:34:07 +0100
To: xmlschema-dev@w3.org
Message-ID: <opsf2125f96mihty@idmm-vaio-vgn>

Although 'schemaLocation' and 'noNamespaceSchemaLocation' are obvious  
places to include schema locations that contain version information, the  
Schema spec makes it very clear that these are optional pieces of  
information that a Schema validator is a complete liberty to ignore.   
Because of that, it's hard to base a versioning solution on schema  
locations.

However, if you are able to guarantee that Schema locations won't be  
ignored, you can agree on which URLs will be used to canonically identify  
your Schema versions, and then use a suitable entity resolver to look up  
an OASIS XML Catalog and map the canonical Schema version URL to the  
actual one.

However, if you use this approach, you should consider using an entity  
resolver that won't download Schemas that are not listed in the Catalog,  
if you need to guarantee application security and hence isolate yourself  
 from the possibility of downloading arbitrary Schemas.

	Cheers,
		Tony.

On Mon, 18 Oct 2004 15:06:39 -0400, Xan Gregg <xan.gregg@jmp.com> wrote:

> XML Schema does provide a place that could be used for version  
> indicator: schemaLocation.  The location URI is a hint for the processor  
> -- seems like a processor could use it as a versioning hint.

-- 
Anthony B. Coates, Director
Information Design, Messaging and Management
mailto:abcoates@idmm.co.uk
Mobile/Cell: +44 (79) 0543 9026
--
MDDL Editor (Market Data Definition Language)
http://www.mddl.org/
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Received on Monday, 18 October 2004 20:34:39 UTC

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