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RE: Removal of Texts and Compatibility

From: Marc de Graauw <marc@marcdegraauw.com>
Date: Fri, 14 Sep 2007 14:54:35 +0200
To: "'David Orchard'" <dorchard@bea.com>, "'www-tag'" <www-tag@w3.org>
Message-ID: <BAD446E2E4AD4C1DACF5301275BA1E19@Marc>

David Orchard:

| I've just posted a couple of entries on Removal of Texts and 
| Compatibility.  The first looks at the question from a Set 
| perspective, and the second from an XML Schema 1.0 
| perspective.  I don't know whether we'll have a chance or 
| interest to discuss at the f2f but I think they are quite 
| applicable to the TAG versioning finding.

These are important ideas. I guess you haven't read my recent posts on
Making Changes Compatible [1], [2], which outline very similar ideas. I've
got a solid use case too: in the Dutch HL7-based EHR, we're effectively at
version 2 (previous versions weren't implemented for production) and -
you'll guess it - the Schema's have no wildcards nor any real provisions for
forward compatibility. Since we in fact do expect the removal of a required
element (amongst others) we need a non-disruptive approach to changes. For
some changes we are in a n:m situation. We have a central National Hub, but
this Hub is not allowed to touch medical content, so can only mediate for
changes in non-medical content. Since the nodes are all healthcare providers
(from GP to hospital) the number of nodes will be large, and moving to later
versions has to be a gradual process where Vn+1 senders don't break existing
receivers. So I'm excited to see your proposals, and I for one do think such
ideas are very relevant for the Versioning Finding. In our situation, it's
not just removal approaches we need, but additions as well since we don't
have the wildcards in place, so you'll find those too in my [1] and [2]. 
Especially your second post with the Schema's is very helpful.



[3] ... to be written yet ...

| http://www.pacificspirit.com/blog/2007/09/13/when_can_language
| _components_be_removed_and_maintain_backwards_or_forwards_comp
| atibility
| http://www.pacificspirit.com/blog/2007/09/13/using_xml_schema_
| 10_when_can_language_components_be_removed_and_maintain_backwa
| rds_or_forwards_compatibility
| Cheers,
| Dave
Received on Friday, 14 September 2007 12:54:51 UTC

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