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RE: ACTION on xsi:type recommendation for variable binding results

From: Howard Katz <howardk@fatdog.com>
Date: Wed, 23 Mar 2005 11:31:55 -0800
To: "Dave Beckett" <dave.beckett@bristol.ac.uk>
Cc: "DAWG Mailing List" <public-rdf-dawg@w3.org>

 > From: Dave Beckett [mailto:dave.beckett@bristol.ac.uk]
 > Sent: Wednesday, March 23, 2005 8:07 AM
 > To: howardk@fatdog.com
 > Cc: DAWG Mailing List
 > Subject: Re: ACTION on xsi:type recommendation for variable binding
 > results
 > On Mon, 2005-03-14 at 16:06 -0800, Howard Katz wrote:

   [ snip ... ]

 > > I think this would be useful to make RDF datatypes accessible
 > > to outside manipulation.
 > Strictly, it makes XML Schema datatypes accessible.  The RDF datatypes
 > are the URI values of the datatype attribute and cannot always be
 > written in xsi:type value forms (the reverse is also true).

Yes, I realized after I sent that that I was being rather more poetic than
technically accurate.

 > > I would recommend we adopt this mechanism, mapping from our
 > > own number/@datatype attribute to an xsi:type representation
 > whenever an XML
 > > Schema simple datatype is present in the variable binding
 > results output,
 > > and emitting the two xmlns declarations on the outer <results> element
 > > wrapper if any xsi:type attributes have been so mapped.
 > That makes the header dependent on the body content, potentially the
 > very last result in a long list could have an XML schema simple datatype
 > value.  I'd prefer to say that *if* any xsi:type is emitted, then the
 > two xmlns declarations must be on the outer results allowing the users
 > to either
 >   1. always emit it (easy)
 >   2. or to do it only if they have an XSD simple datatype in a result
 >   (requires some storage for the full results or some other knowledge).
 > I'd expect most people would chose #1.

I don't think it's a big deal either way. FWIW I've noticed that Saxon
constructs the appropriate declaration if it encounters any predefined
prefixes in a query result. It's also similar to what you have to do in
order to construct the <variables> block, no? Don't you need to pre-process
the entire result set first in order to determine the union of all bound
variables before you can emit?

 > You also suggest just applying this to the XML Schema simple datatype, I
 > assume exclusively.  Would other xsi:type values be allowed to be
 > emitted if the application knew the RDF datatype URI <> XML qname
 > mapping?  Or forbid this?

Sorry, I'm not understanding what you're asking here, Dave ...

 > One other thought is that the additional in-scope XML namespaces would
 > "infect" any XML content given.  I'm not sure that's a big problem,
 > compared to that with RDF/XML's parseType="Literal" where C14N appears.
 > Dave
 > > Howard
 > >
 > > [1]
 > >
> ml
> [2] http://www.w3.org/TR/xmlschema-1/#xsi_type
> [3] http://www.w3.org/TR/xmlschema-1/#d0e16860
> [4] http://www.w3.org/TR/2003/REC-soap12-part2-20030624/#enctypename
> [5]
> ml
Received on Wednesday, 23 March 2005 19:32:11 UTC

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