Re: [xml-dev] Non-schema approach to web service design: comments?

[Tech Rams <techmailing@yahoo.com>]

Well...my aim was not to glorify the OOness of XSD - I
do realize the eccentricities of extensions.

My aim was to point out that a schema is an outline of
data (as in a data structure) - it does not outline
any processing requirements on the data - either at
the time of creating the data, or at the time of
processing it.

As well as we can argue that we need constructs to
specify how to generate data (like it must be the
checksum of some other data), we can also argue the
need to specify how to interpret the results (in a web
service for example).

Such requirements, unfortunately, are still in the
domain of human communications (external
documentation), as far as I know.

-rams



--- Amelia A Lewis <amyzing@talsever.com> wrote:

> On Fri, 28 Oct 2005 13:29:09 -0700 (PDT)
> Tech Rams <techmailing@yahoo.com> wrote:
> >Whether or not we like it, XSD/WSDL are based on
> >programmatic and object-oriented data structures.
> If
> 
> Err, what?
> 
> I s'pose it depends on which version of WSDL you're
> talking about; 1.1
> was designed to support SOAP when SOAP was still an
> acronym.  For that
> matter, WSDL 2.0 can be viewed through the prism of
> object-oriented
> programming or even (ugh) RPC.  It can also be
> viewed, however, as a
> contract for the exchange of messages.  And it isn't
> tied exclusively to
> W3C XML Schema, either.
> 
> As for W3C XML Schema, describing it as based on
> programmatic and
> object-oriented data structures is, at best,...
> kind.  In fact, the
> requirements given to the working group that
> ultimately produced it were
> as psychotic as the ultimate result (hardly a
> surprise), requiring that
> the language be able to specify traditional "markup"
> types, database
> types (possibly one could refer to this as
> "programmatic", but I
> wouldn't), certain over-hyped internal
> pseudo-pointer types, as well as
> the noted 'programmatic' types (which I think might
> be better labelled as
> 'register types', conforming to bit patterns in CPU
> registers).  W3C XML
> Schema has absolutely nothing object-oriented about
> it, though.  Its
> techniques for deriving data structures from
> previously-defined types
> (extension and restriction) does *not* model
> inheritance in
> object-oriented languages.  Worst of all, many of
> its types differ in
> significant detail from the types (in various and
> sundry languages) to
> which they are mapped, with consequences that are
> amusing or disastrous
> (depending upon your sense of humor and your job
> security when it occurs).
> 
> Possibly we're stuck living with this.  And probably
> we're stuck with
> procedural and object-oriented languages ruling the
> roost and defining
> the consensus set of datatypes.  That doesn't,
> however, make W3C XML
> Schema's set of types match the consensus set, nor
> does it make it
> object-oriented.  Likewise, it's hard to regard WSDL
> 1.1 as
> object-oriented when it lacks the facility to base
> one portType on the
> definition of another, though there are OO dialects
> that use aggregation
> to the exclusion of inheritance.  Nor is it likely
> (in my opinion, which
> is undoubtedly biased given that I've spent many
> hours teleconferencing
> on the subject) that we'll be "stuck with" WSDL 1.1
> once 2.0 is completed
> (soon, I hope), nor is it necessary to view WSDL 2.0
> as exclusively
> representing procedural or OO programming models.
> 
> Amy!
> -- 
> Amelia A. Lewis                    amyzing {at}
> talsever.com
> Confidence: a feeling peculiar to the stage just
> before full
> comprehension of the problem.
> 
>
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