Re: using namespaces to version

[Brian Grainger <bgranam@home.com>]

----- 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
8-4-4-4-12
characters.

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
namespace
layout:

versionid="cid:uuid:" followed again by a uuid, but of course different from
the
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
notation
to use for versioning.

Regards,
Brian