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RE: WSDL WG request for adding multiple version extensibility into Schema 1.1

From: David Orchard <dorchard@bea.com>
Date: Sat, 14 Feb 2004 22:31:08 -0800
To: "'Bijan Parsia'" <bparsia@isr.umd.edu>, "'Mark Baker'" <distobj@acm.org>
Cc: <www-ws-desc@w3.org>
Message-ID: <02be01c3f38d$4bb07660$6501a8c0@beasys.com>

Bijan,

muchos thanks for the response.  Comments inline.

> On Feb 13, 2004, at 8:54 PM, Mark Baker wrote:
>
> > On Fri, Feb 13, 2004 at 12:06:01PM -0800, David Orchard wrote:
> >> <name>
> >> 	<first>Dave</first>
> >> 	<last>Orchard</last>
> >> </name>
> >>
> >> <name>
> >> 	<first>Dave</first>
> >> 	<last>Orchard</last>
> >> 	<middle>Bryce</middle>
> >> </name>
> >>
> >> <name>
> >> 	<first>Dave</first>
> >> 	<last>Orchard</last>
> >> 	<middle>Bryce</middle>
> >> 	<suffix>II</suffix>
> >> </name>
> >> We want these 3 of these documents to be valid against the
> 3 schemas.
> >> It
> >> seems that the simplest change would be to have a "low priority"
> >> wildcard as
> >> mentioned in previous discussions. The schemas using this would be
> >> something
> >> like:
> >
> > Can I ask why you wouldn't just use RDF/XML in that case?
>
> Because it's probably the wrong thing?
>
> >   It gives you
> > exactly the kind of extensibility you seem to require.
>
> Actually no. He requires "ignore unknowns" extensibilty *with*
> validation. If you try to validate a specific profile of RDF/XML, you
> could have similar problems.
>
> Presumably, you want *RDF*, not RDF/XML per se.

Well, the reason that I want "ignore unknowns" is because I know that
"ignore unknowns" has been deployed on the web for >10 years and it works
for versioning.  If there's another solution, I'm really really really
interested in it.

>
> > I understand that there's pushback against RDF/XML in WS circles,
>
> Not from me, semantic web person that I am :)

and that raises my opinion of you significantly.

>
> > but
> > really, solving this problem is *exactly* what RDF was designed for.
>
> Acutally only sort of. XML was, in part, similarly designed.
> Insofar as
> both are coming form the semistructured data cmmunity (which is more
> true for XML, actually), they tend to have been built to handle such
> problems. XML Schema much less so. And OWL and RDF(S) are 1) not
> *really* aiming at this and 2) have deep difficulties with *data*
> *validation* (see current threads on public-sws-ig).
>

Bijan, could you provide some of the examples of the difficulties?

> > If you want to give me a detailed example and the
> > versioning/extensibility requirements, I'd be happy to do the
> > conversion to RDF/XML.
>
> Won't help. And wouldn't meet the requirements anyway. I mean, if you
> want to leave it merely wellformed XML, you solve the problem too.
>

wellformed ain't right.  I'd like the type information for valid types.

So, what are the requirements:
1. Types that are valid have type information
2. Types that are not known do not break validation
3. Types allow for arbitrary extensibilty in ways not predicted by the
Version N schema author.
4. Types that are not known and optional can be added without breaking
compatibility (same as #2?)
5. Types that are known and not allowed break validation.

Assuming that these are roughly the requirements for doing compatibile
versioning, Bijan, what would the RDF/XML look like to express these
assurances?  How about taking the V1 (name(first,last)) and V2
(name(first,last,middle)) examples.

And thanks for the time to educated a SW-philistine like myself.  It's so
rare to encounter a SW person who doesn't say "drink the kool-aid" whenever
possible that I see this as an opportunity to get educated.

cheers,
Dave
Received on Sunday, 15 February 2004 01:30:47 UTC

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