- From: Jacek Kopecky <jacek@systinet.com>
- Date: Wed, 2 Jan 2002 19:44:27 +0100 (CET)
- To: Noah Mendelsohn <noah_mendelsohn@us.ibm.com>
- cc: "peter.hendry" <peter.hendry@capeclear.com>, xml-dist-app <xml-dist-app@w3.org>
Noah,
at first it was not clear to me that you're reacting to my post,
so maybe in some future post you might indicate that in a way.
Thanks in advance. 8-)
Back to business: I may be underestimating the value of
datatypes in XML Schema, as I see that language mainly poised for
validation. I'm nervous about using that language for description
of data structures, in my opinion it's too powerful for that
task, with its <all>s and <sequence>s, with its <choice>s and
whatnot.
AFAIK XML Schema is not even able to describe all the possible
structures in the XML data model (a tree), only a somewhat
restricted subset. I don't think going further would be
practical for XML Schema.
Anyway, I'm not against using XML Schema simple data types, on
the other hand I think that higher-level data structures are too
application-specific.
We can agree that NameValue pair (or KeyValue) is used often
where SOAP Encoding is used but I don't see in which way this
struct is special and so why it should be a part of SOAP
Encoding.
Best regards,
Jacek Kopecky
Senior Architect, Systinet (formerly Idoox)
http://www.systinet.com/
On Fri, 21 Dec 2001, Noah Mendelsohn wrote:
>
> Whatever the implications for the SOAP design, I think you are somewhat
> underestimating the reason for builtins such as positive integer in the
> schema language. Schema is NOT just used for validation. It is equally
> important as input to tools that do mappings to database languages,
> programming languages, etc. For these purposes, having well known and
> agreed upon names for commonly used types is extremely important.
> Otherwise, recognizing such types becomes a theorem proving exercise rather
> than a simple recognition of type names (e.g. you would have to prove that
> the facet restrictions on integer actually resulted in positive only. If,
> for example, someone restricted the lexical space to forbid minus signs,
> that might do it, but I bet it would be a mess to detect.)
>
> I think there is an analogy for SOAP encoding. Where we standardize well
> known type names, tools are more likely to be able to generate effective
> programming language mappings automatically. On the other hand, having too
> many such well-known types makes the spec too big, and tends to get us in
> the business of defining types that are more special purpose. I think the
> NameValue and NameValueList types under discussion are in the grey area
> where you can make a good case either way. Thanks very much.
>
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Received on Wednesday, 2 January 2002 13:44:35 UTC