W3C home > Mailing lists > Public > www-rdf-interest@w3.org > May 2001

Re: QName Problem Isn't One

From: Aaron Swartz <aswartz@swartzfam.com>
Date: Sun, 06 May 2001 10:22:13 -0500
To: "Sean B. Palmer" <sean@mysterylights.com>, RDF Interest <www-rdf-interest@w3.org>
CC: Jonathan Borden <jonathan@openhealth.org>
Message-ID: <B71AD653.AD1D%aswartz@swartzfam.com>
Sean B. Palmer <sean@mysterylights.com> wrote:

> The use of the XSD namespace simply denotes that one is referring to a
> set of names within that namespace. Hence, XSV uses something like:-
> 
>    {http://www.w3.org/2001/XMLSchema}element
> 
> If you change the namespace name, then you are referring to a
> different set of names altogether; end of story.

Exactly Sean, you are making my point perfectly clear. Since RDF is not
using XSchema to refer to a namespaced datatype element (hey, even XSchema
does not even use XSchema refer to a namespaced datatype element!) this use
is just fine. IOW, we're not referring to one of the elements or attributes
"in" the XML Schema namespace -- instead, we're simply referring to a set of
URIs that happen to start with the character sequence
"http://www.w3.org/2001/XMLSchema#". To confuse other processors by making
them think we were using XML Schema elements would be a serious mistake.

We would not want the namespaces to be equal, since they are not.

>> http://www.w3.org/2001/XMLSchema#   (notice the extra # sign)
>> 
>> An XSD processor will not recognize this as an XML Schema
>> document (good -- it isn't) and will not process it.
> 
> Er... but the http://www.w3.org/2001/XMLSchema namespace is not an XML
> Schema document either - are you saying it should be?

Err, no, it's a namespace. What do you mean?

>> The secondary point -- that a different namespace is used in each
>> document -- is done correctly, since to use the same namespace would
>> needlessly confuse processors.
> 
> Come again? Namespaces are only identical when they're identical. If
> you're using a new namespace, then you should state in some
> specification both why you're using it, and what it represents.

This is a tenuous area, I admit. RDF does not state the meaning of the
namespaces which it uses, but nor does XMLNS. The Dublin Core namespace does
not describe its meaning either. However, I would venture to say that RDF
uses a namespace to mean "the set of all URIs generated by adding one or
more XMLName characters to the end of the namespace".

BTW, Brian, this whole thread should be linked in to:
http://www.w3.org/2000/03/rdf-tracking/#rdfms-qname-uri-mapping

-- 
[ Aaron Swartz | me@aaronsw.com | http://www.aaronsw.com ]
Received on Sunday, 6 May 2001 11:22:37 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:49 GMT