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Re: using namespaces to version

On 04/05/2001 15:43:01 C. M. Sperberg-McQueen wrote:

>In other words, the relation of namespace to schema is many-to-many,
>not one-to-one.  This turns out to be a hard pill for some to swallow,
>but I think it is time to accept the logical consequences of our
>designs.  (The people I know who want a one-to-one relation are,
>as far as I can tell, still fighting the battles involved in the
>development of the namespaces rec.  Let it go, friends! Let it go!)

Yes, the intersection between schemas, namespaces, and versioning is certainly
proving to be cathartic for me too.  However, in this many-to-many world, how
does my application determine which versions of all the many imported and
included schemas apply to a particular instance document?  Be aware that "your
application needs to be flexible and robust" is not a suitable answer, because
in the financial world contextual mistakes can be worth millions of dollars.  I
need to know exactly which version of each element was used, and I really need
this information to be available with the DOM tree that my parser returns.  The
situation you describe sounds fine if you don't expect to have to version your
elements, because their meaning isn't expected to change with time.  This will
be true in some areas, but certainly completely incorrect for others.  You
cannot always invent a new name just because the semantics change in some way.
Nor do I really see us wanting to have a separate namespace for each individual
element (and wouldn't that be a great bandwidth blow-out for our instance
documents).  There seems to be a piece of the puzzle that is missing, certainly
for enterprise usage.  Or is there something obvious that I am missing here?

Anthony B. Coates
Leader of XML Architecture & Design
Chief Technology Office
Reuters Plc, London.

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