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Compatible evolution of schemas

From: David Orchard <dorchard@bea.com>
Date: Thu, 22 Jan 2004 09:41:16 -0800
To: <www-ws-desc@w3.org>
Message-ID: <039f01c3e10e$f1162d20$6401a8c0@beasys.com>

From my blog entry, [0]:

I've finally published the opus on what can and could be done to provide
compatible evolution of Schemas [1] . It lists all the ways people can do
extensibility and versioning now, such as wildcards (##other, ##any,
##targetnamespace), Extension Elements, and Type Extension. And then it goes
into a number of things, including potential changes to Schema, that could
be done to better meet the requirements for loosely coupled Web components.
I argue in Web Services = or != Distributed Objects [2] that Schema authors
tend to make tightly coupled Web services because they can't fully version
or evolve them. I proposed one simple schema design with related rules in
Versioning XML Languages [3], but I didn't have time to do justice to all
the current and possible techniques. That deficiency I consider rectified.

I've also made a collection of links to mine and others (notably David Bau)
writings on extensibility and compatibility in my compatibility index page
[4]. You can see the relationship amongst the writings on the importance of
loose coupling, how extensibility and versioning enable it, what you can and
can't do with XML schema today.

I hope this material helps in discussions about compatible evolution of web
service descriptions.  I would also be glad to do a tutorial or overview at
the WSDL WG F2F next week.

Cheers,
Dave Orchard

[0]
http://www.pacificspirit.com/blog/2004/01/19/providing_compatible_schema_evo
lution
[1]
http://www.pacificspirit.com/Authoring/Compatibility/ProvidingCompatibleSche
maEvolution.html
[2]
http://www.pacificspirit.com/blog/2004/01/12/web_services_or_distributed_obj
ects
[3] http://www.xml.com/pub/a/2003/12/03/versioning.html
[4] http://www.pacificspirit.com/Authoring/Compatibility/
Received on Thursday, 22 January 2004 12:40:02 GMT

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