keys, keyrefs, and the default namespace

[Joseph Rank <jr...@austin.rr.com>]

Hello, all.

I'm using Xerces 2.4.0 on Linux and am having no luck getting the SAX 
parser to enforce XML Schema identity constraints using the default 
namespace.

On the other hand, if I specify an explicit namespace for my schema, and 
the XPath expressions in my key and keyref selectors use the qualified 
name that includes the prefix, everything works.

So, having defined a document root, a child element of the root, and the 
child's children, "thing" and "thingRef", this

<xsd:schema xmlns="http://example.com/schema"
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"
   targetNamespace="http://example.com/schema">

...

   <xsd:key name="thingKey">
     <xsd:selector xpath=".//thing"/>
     <xsd:field xpath="@code"/>
   </xsd:key>

   <xsd:keyref name="thingKeyRef" refer="thingKey">
     <xsd:selector xpath=".//thingRef"/>
     <xsd:field xpath="@id"/>
   </xsd:keyref>

...

</xsd:schema>

doesn't throw any errors when the thingRef ids don't match the thing 
codes in an instance document (which was a surprise; I expected an 
identity constraint error), but this

<xsd:schema xmlns:pre="http://example.com/schema"
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"
   targetNamespace="http://example.com/schema">

...

   <xsd:key name="thingKey">
     <xsd:selector xpath=".//pre:thing"/>
     <xsd:field xpath="@code"/>
   </xsd:key>

   <xsd:keyref name="thingKeyRef" refer="pre:thingKey">
     <xsd:selector xpath=".//pre:thingRef"/>
     <xsd:field xpath="@id"/>
   </xsd:keyref>

...

</xsd:schema>

does. Shouldn't the case with the default namespace behave the same as 
the case with the explicit namespace?

Any insight would be appreciated,

-Joe