AW: [xml] libxml schema validation - conflict result on attributevalidation

["Buchcik, Kasimier" <k buchcik 4commerce de>]

Hi, 

> -----Ursprüngliche Nachricht-----
> Von: xml-bounces gnome org [mailto:xml-bounces gnome org] Im 
>
> I'm trying libxml on a very simple same file and got some rather
> conflicting result. I'm still learning schema and libxml so any tip is
> much appreciated.
>
> Thanks.
>
> result:
> correct/test.xml:2: element sample: Schemas validity error : Element
> '{http://www.test.com}sample', attribute 'abc': The attribute 'abc' is
> not allowed.
> correct/test.xml:2: element sample: Schemas validity error : Element
> '{http://www.test.com}sample': The attribute
> '{http://www.test.com}abc' is required but missing.
> correct/test.xml fails to validate

This looks like a conflict at first glance, but it isn't.

The first error reports: "The attribute 'abc' is not allowed."
Thus, an attribute "abc" in *no* namespace in not allowed.

The second error reports: "The attribute '{http://www.test.com}abc' 
is required but missing."
Thus, an attribute "abc" in the namespace "http://www.test.com"; is
defined to be required, but is missing.

> xsd:
> <?xml version="1.0" encoding="UTF-8" ?>
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";
> targetNamespace="http://www.test.com"; elementFormDefault="qualified"
> xmlns ="http://www.test.com";>
>
> <xs:attribute name="abc" type="xs:integer"/>

This is a global attribute declaration. Global element/attribute
declarations declare the element/attribute to be in the
*targetNamespace". So you declare the attribute "abc" to be
in the namespace "http://www.text.com";.

> <xs:element name="sample">
>     <xs:complexType>
>         <xs:sequence>
>                 <xs:element name="test"/>
>         </xs:sequence>
>         <xs:attribute ref="abc" use="required"/>
>     </xs:complexType>
> </xs:element>
> </xs:schema>
>
>
> xml:
> <?xml version="1.0" encoding="ISO-8859-1"?>
> <sample xmlns="http://www.test.com";
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; abc="23">
> <test/>
> </sample>

The attribute "abc" in this instance document is in *no* namespace;
thus not the one you actually declared in the schema.

I hope this clarifies the error reports.

To fix your scenario, either you declare a *local* attribute in
the schema (you also may want to read about the implications of
"attributeFormDefault"):

<xs:complexType>
  ...
  <xs:attribute name="abc" use="required"/>
</xs:complexType>

... - this way the attribute "abc" will be in no namespace -,
or you fix your instance document by putting the attribute
"abc" into the declared namespace:

<test:sample xmlns:test="http://www.test.com";
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; test:abc="23">


Regards,

Kasimier