On Tue, 19 Jul 2005 10:47:52 +0100, CRAWFORD, Mark <>
wrote:
> And if we don't minor version our namespaces?
In transactional messaging, there can be the risk of legal consequences if
you don't know exactly which version of a message Schema applies to an
message instance, since each Schema version is like a different version of
a contract, and you introduce a business risk of you decide do something
under the terms of a contract, without checking which version of the
contract actually applies.
The upshot is that each message instance really should identify which
Schema, and which version of that Schema, applies to it. The most popular
way to do this is to have a unique namespace for each version of each
Schema. The way I like to do it, sometimes in addition to the namespace
technique, is to provide top-level attributes which have a fixed value
that is required to appear, and which identify the Schema and version.
Sometimes people try to use the 'schemaLocation' to provide Schema version
information, but this is a fragile technique that I don't recommend in
general.
So, there is some flexibility in the exact solution that could be chosen
for this reason (explicit version identification). I do think we need to
be thinking of this when choosing the UBL solution.
Cheers, Tony.
--
Anthony B. Coates
London Market Systems Limited
33 Throgmorton Street, London, EC2N 2BR, UK
http://www.londonmarketsystems.com/
mailto:
Mobile/Cell: +44 (79) 0543 9026
[MDDL Editor (Market Data Definition Language), http://www.mddl.org/]
[FpML Arch WG Member (Financial Products Markup Language),
http://www.fpml.org/]
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