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Re: using namespaces to version

----- Original Message -----
From: "Warren Hedley" <w.hedley@auckland.ac.nz>
To: <xml-dev@lists.xml.org>
Sent: Wednesday, May 02, 2001 4:29 PM
Subject: using namespaces to version

> I'm wondering if anyone on the list has any strong opinions about
> the use of namespaces for versioning. In particular, am I likely
> to run into any problems if I base my namespaces on the Dublin Core
> format shown below?

I've used a system for versioning schemas based on uuid's which seems
to work quite well, although your mileage may vary.

I define a fixed namespace using the 'urn' prefix:

xmlns:foo="urn:uuid:" followed by a uuid in random hex notation of

To version the schema, I insert a 'versionid' attribute into the root
element of the
schema of type xsd:uriReference, and then use notation similar to my

versionid="cid:uuid:" followed again by a uuid, but of course different from
namespace uuid.

That way, my schema namespace never changes, and if I need to check the
version, I just refer to the 'versionid' attribute. The 'cid' prefix is
defined by
IANA, and means 'content identifier', so it seemed to me like the right
to use for versioning.