RE: Schema Instance why does xmlns attribute causes problem?

A test element in no namespace and a test element in namespace
<http://people.rit.edu/~jjp1820/770/project/xtml_test>
http://people.rit.edu/~jjp1820/770/project/xtml_test are as different as
chalk and cheese - literally. They have competely unrelated names. A schema
defines rules for validating an element of a particular name, and if you
change the element's name, the rules don't apply. And the namespace is part
of the name, just as your surname is part of your name.
 
Michael Kay
http://www.saxonica.com/


  _____  

From: xmlschema-dev-request@w3.org [mailto:xmlschema-dev-request@w3.org] On
Behalf Of Joseph Pecoraro
Sent: 13 November 2008 17:29
To: xmlschema-dev@w3.org
Subject: Schema Instance why does xmlns attribute causes problem?


Hello,

I have a quick question.  I'm trying to validate an XML document using
a Schema and I ran into an issue.  I can't tell, based on the specification
why what I have appears invalid.

I have the following: 

<test test_id="1"
    xmlns="http://people.rit.edu/~jjp1820/770/project/xtml_test"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://people.rit.edu/~jjp1820/770/project/xtml_test
 
http://people.rit.edu/~jjp1820/770/project/xtml_test.xsd">

Which appears invalid in the tool that I'm using.

But, Once I remove the plain xmlns attribute and get the following
which appears valid:

<test test_id="1"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://people.rit.edu/~jjp1820/770/project/xtml_test
 
http://people.rit.edu/~jjp1820/770/project/xtml_test.xsd">

I would like to know why the top, previous example is "invalid."  To me,
it means the exact same thing, but its slightly redundant.  I will certainly
use the bottom from now on, but I would be interested in knowing
how, why, or even if the top syntax is invalid.

Thanks guys,
Joseph Pecoraro