Re: [xml] Question about default namespace with XML Schema

[Kasimier Buchcik <kbuchcik 4commerce de>]

Hi,

On Mon, 2005-05-02 at 11:03 +0200, GUY Fabrice wrote:
> Hi,
>
> I'm using this schema :
>
> <?xml version="1.0" encoding="ISO-8859-1"?>
> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema";>
>   <xsd:element name="ELEMENTS">
>     <xsd:complexType>
>       <xsd:sequence>
>         <xsd:element name="element" type="xsd:string" minOccurs="0"
> maxOccurs="unbounded"/>
>         <xsd:element name="element2" type="xsd:string" minOccurs="0"
> maxOccurs="unbounded"/>
>       </xsd:sequence>
>     </xsd:complexType>
>     <xsd:key name="key">
>       <xsd:selector xpath="element"/>
>       <xsd:field xpath="."/>
>     </xsd:key>
>     <xsd:keyref name="keref" refer="key">
>       <xsd:selector xpath="element2"/>
>       <xsd:field xpath="."/>
>     </xsd:keyref>
>   </xsd:element>
> </xsd:schema>
>
> with this xml file :
>
> <?xml version="1.0" encoding="ISO-8859-1"?>
> <ELEMENTS>
>     <element>test1</element>
>     <element>test2</element>
>     <element2>test2</element2>
> </ELEMENTS>
>
> And that works perferctly fine.
>
> But when I try to use the default namespace in the schema (to avoid
> using the xsd: prefix), I get this message when I validate it with
> xmllint :
> test.xsd:14: element keyref: Schemas parser error : keyRef 'keref':
> References from this schema to components in the namespace
> 'http://www.w3.org/2001/XMLSchema' are not valid, since not indicated
> by an import statement.

The error report is OK. The "refer" and the "ref" attributes hold
QNames, acting as references to schema components. So the value "key"
expands to the QName "{http://www.w3.org/2001/XMLSchema}key";, for which
there is no schema component; furthermore, references to "foreign"
namespaces (i.e namespaces other than specified in targetNamespace)
are disallowed if not explicitely <import>ed by the schema.

> Here's my schema with the default namespace :
>
> <?xml version="1.0" encoding="ISO-8859-1"?>
> <schema xmlns="http://www.w3.org/2001/XMLSchema";>
>   <element name="ELEMENTS">
>     <complexType>
>       <sequence>
>         <element name="element" type="string" minOccurs="0"
> maxOccurs="unbounded"/>
>         <element name="element2" type="string" minOccurs="0"
> maxOccurs="unbounded"/>
>       </sequence>
>     </complexType>
>     <key name="key">
>       <selector xpath="element"/>
>       <field xpath="."/>
>     </key>
>     <keyref name="keref" refer="key">
>       <selector xpath="element2"/>
>       <field xpath="."/>
>     </keyref>
>   </element>
> </schema>
>
> Have I missed something (namespace declaration,...) or this is a bug ?

If you want the schema to have no targetNamespace, you need to use a
prefix for the XSD nodes, or avoid references to components; the latter
being quite unpractical.

Regards,

Kasimier