Re: Two messages from James Clark that ought to be read

James is absolutely correct.
We've been doing a Proof-of-Concept with a key goal of
separating validation from application or even data
layers. Our test case requires lighter validation at
the beginning and stronger validation towards the end.

The test case is in international freight logistics.
Here we have a customer provide initial booking
information and then ask an operations person to
complete the data set.

Our solution is to apply different schemas temporally
(at different times within the process) or even
dependent on the user role.

We are somewhat new to XSDs, but have found them very
useful for data typing, setting a field to be
non-nillable, etc. Unfortunately, we've not found
mechanism to support heuristic validation rules such
as a Estimated Time of Arrival must be equal to or
less than an Estimated Time of Departure.

It would be useful if this type of logic could be
embedded within the XSD rather than a piece of Java or
even possibly an XSLT. 

Again, these heuristic validation rules must also be
applied temporally.


--- Tim Bray <> wrote:
> from xml-dev:
>   -Tim

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Received on Monday, 10 June 2002 11:58:01 UTC