Fw: XML Tower of Babel - bring on UBL

[jon.bosak@sun.com]

Great article.  The author has also very helpfully contributed a
bug report against one of our example documents.

   http://www.it-analysis.com/article.php?articleid=11971

Jon

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XML Tower of Babel - bring on UBL
Thursday 10th June 2004

XML is taking over the world for all sorts of good reasons (see my
earlier article
http://www.it-director.com/article.php?articleid=11152 ). But just
as we thought that it would solve all our problems and let us
build a tower up to the gods babble intervenes.

XML has allowed messages to be passed from one system to another
in such a way that they can be parsed, dissected, queried and
rebuilt, but it only deals with the syntax and not the
semantics. To take a simple example, different messages using
different schemas could have tags like: zip, zipcode, zip_code,
post-code, post_code, postal_code, or PostalZone, all of which in
a generic sense relate to the same type of data. So a message from
one schema has to be transformed into another schema before it can
be processed.

This causes considerable redundant processing as well as adding
significant opportunities for errors, potential security exposures
and a need for additional modelling and testing. It also reduces
the opportunity for reuse and discrete services. For example, it
should be possible to develop a service that can be handed any XML
stream and it will add the insurance group for the PostalZone and
pass the message back; this would be much easier if the tag was
always the same.

Individual element names are one level of the problem and the next
level of problem is messages for typical transactions such as an
invoice. Again the advantage of a single agreed format would be
immense.

Well, OASIS looks as if it has solved this problem with the
publication of its Committee draft of the Universal Business
Language (UBL) 1.0 last month. This is a major piece of work which
is freely available and I believe should be the standard by which
all new XML schemas and messages are built. It provides for
extensions and is obviously not yet universal in its coverage. It
does however cover many of the basic concepts and elements needed
as its documents and component library are designed to support a
typical order-to-invoice procurement cycle. It includes the
following document types: Order, Order Response Simple, Order
Response (detailed), Order Change, Order Cancellation, Despatch
Advice, Receipt Advice and Invoice.

My intial review of the standard shows a great deal of thought and
understanding from the members of the committee. Given its size it
is remarkably easy to navigate around and find bits of
interest. Ever since my early data modelling experience, with a
pre-release version of IMS/DB, deciding how best to deal with
addresses has been a major issue. So I looked at this area in
particular and it does seem to work well and give the flexibility
needed (this is partly due to the greater flexibility of XML over
IMS) and I can easily see this becoming the standard. One small
criticism is that the definitions are somewhat terse and it is
probable that over time they will need to be expanded to ensure
real commonality of semantics.

In short an excellent version one with plenty of promise of more
to come.

For the detail go to http://docs.oasis-open.org/ubl/cd-UBL-1.0/
and you still have time to comment on the draft.

Peter Abrahams
Bloor Research