Re: [xml-dev] RE: Caution using XML Schema backward- or forward-compatib

[Thomas Lord <lord@emf.net>]

Costello, Roger L. wrote:
> I think that for a client to be able to utilize a web service, the web
> service must specify three things:
>
> (1) Syntax of the data that the web service makes available to clients;
> use a grammar-based language such as XML Schemas, or RELAX NG, or DTD.
>
>   

Ok.


> (2) Relationship constraints (e.g. co-constraints) on the data; use
> Schematron.
>
>   

Seems a bit arbitrary.   Why "relationship constraints" of that 
particular form?
What's your theory, here?   Your claim wasn't that Schematron can be useful
but that "[in order] for a client to be able to utilize a web service 
[....]" which is
a remarkably strong claim.

 


> (3) Semantics of the data; use a data dictionary, or English prose, or
> RDF/S, or OWL, some combination thereof.
>
>   

Again, what's your theory?   Some notation that usefully indicates semantics
seems a good idea, I grant you.   Obviously, also, service has to be 
documented somewhere.
How did you get from there to "English prose, RDF/S, or OWL, some
combination thereof"?


(2) and (3) suggest investments, presumably with some return.   They 
also suggest
suggestions competitive with a lot of well developed theory in program 
typing and
in modeling the semantics of programs.   So, why are the technologies 
and approaches
you suggest the right choice here?

-t