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Re: Schema validation terminology

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 12 Dec 2000 11:42:49 +0000
To: Michael Anderson <michael@research.canon.com.au>
Cc: "xmlschema-dev@w3.org" <xmlschema-dev@w3.org>
Message-ID: <f5bbsuhq30m.fsf@cogsci.ed.ac.uk>
Michael Anderson <michael@research.canon.com.au> writes:

<snip/>

> > The schema document as a whole has constraints on it independent of it
> > use in a particular validation episode.  <snip>
> 
> 
> What are these independent constraints?  In reference to a previous
> post by you (ht), is it (1) and (2)?
> 
> >
> >   1) Any schema documents involved must be schema-valid wrt the schema
> >      for schemas;
> >   2) They must satisfy the additional Schema Representation
> >      Constraints;
> >   3) The schema they correspond to must satisfy the Constraints on
> >      Schemas.
> >
> > Failure to satisfy these conditions is an error, and processing with
> > that schema should stop (except to provide additional feedback on
> > other errors).

All three.

> In reference to the specs, are these independent constraints the
> "Schema Representation Constraints" (which I thought included schema
> valid wrt the schema for schemas)?  And thus all the other dependent
> constraints, that concern errors in the schema, ie "Constraint on
> Schemas" and "Schema Information Set Contribution" can only be
> checked during an instance validation - as you don't know which
> components will be used until then?

I'm afraid you're being misled by the fact that XSV is incomplete, and 
doesn't check derivation correctness completely yet.  SRCs (including
conformance to the SforS as you point out) and COSs
should be checked comprehensively at first processing _as far as_
_possible given the provision for late binding_.  In practice I
suspect this means that processors won't check derivation at all until 
runtime, this is a bit of a grey area I guess.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
Received on Tuesday, 12 December 2000 06:42:51 GMT

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