Re: [xml-dev] [Summary] Big hierarchy of XML Schema documents ... which

[Mukul Gandhi <gandhi.mukul@gmail.com>]

On Thu, Aug 5, 2010 at 9:51 PM, Dowling, Nora M. <ndowling@mitre.org> wrote:
> During the validation of an XML document, is there a difference between the validator "loading a schema" and "validating the schema as it is loaded"?

Loading a schema (for example loading a specific ##.xsd file into a
memory object and doing no other checks to the constructed object) and
"validating the schema as it is loaded" (this means checking that the
memory object [constructed by loading say some ##.xsd file] satisfies
schema component constraints) surely have different meaning (i.e, what
is being done in these two cases is entirely different -- naively
speaking loading and validating are different concepts :)).

> 1) the XML document being validated never makes use of the schema;

I think it's best for the XML schema validator to simply discard the
associated schema's (this makes logical sense, and there is no point
for the validator to incur unnecessary overhead to load schema's in
this case), as soon as the validator is able to determine that the
schema's won't be needed for validating an XML document.

> 2) it makes use only of the valid parts of the linked-in schema;

I think, that XML schema's participating in a validation episode, need
to satisfy constraints defined for the overall schema (if we are
talking about the W3C XML Schema spec) and also the constraints on
each schema component that exist in the overall schema. So I believe,
that if certain parts of the XML schema document are not valid "XML
schema components", then none of parts (even if certain parts are
valid if you think so) of this schema document are usable during XML
schema validation, and the XML schema validator at some point during
validation process will abort the entire validation episode.

> 3) it uses the "invalid" definition in the schema?

I think, the XML schema validator will give an error (either the
validity error, "schema component error" or both) in this case at some
point during the validation episode, and the entire validation episode
will be aborted.



-- 
Regards,
Mukul Gandhi