RE: [xml-dev] Can we treat XML elements and attributes as sets

From
Mukul Gandhi <>
To
Michael Kay <>,
Date
2005-08-21T14:21:46Z
ID
<>
Thread
RE: [xml-dev] Can we treat XML elements and attributes as sets
Thanks Mike for your comments..

Regards,
Mukul

--- Michael Kay <> wrote:

> The terminology of each of the specs is slightly
> different.
> 
> XML doesn't know about namespaces at all
> (unfortunately).
> 
> The XML namespaces spec says "If the URI reference
> in a default namespace
> declaration is empty, then unprefixed elements in
> the scope of the
> declaration are not considered to be in any
> namespace. " 
> 
> The Infoset says, of the [namespace name] property
> of an element information
> item: " If the element does not belong to a
> namespace, this property has no
> value."
> 
> The XPath 2.0 data model says that the name of an
> element or attribute is a
> QName as defined by the xs:QName data type in XML
> Schema. XML Schema Part 2
> says that a QName contains a namespace name and a
> local part; oddly, it does
> not mention that the namespace name might be absent
> or null.
> 
> Most of these specs avoid using the dreaded "null"
> word, probably because of
> its traumatic history in relational databases. But
> XSLT says (in 3.1):
> 
> "Throughout this specification, an element or
> attribute that is in no
> namespace, or an expanded-QName whose namespace part
> is an empty sequence,
> is referred to as having a null namespace URI." 
> 
> This is to enable the spec to retain terminology
> that's familar from XSLT
> 1.0.
> 
> Note that a namespace URI cannot itself be null; but
> a property of an object
> that might otherwise hold a namespace URI, and that
> might be referred to as
> "the namespace URI property", can be said to be null
> when the namespace URI
> is absent.
> 
> Michael Kay
> http://www.saxonica.com/



		
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