- From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
- Date: 07 May 2001 12:18:03 +0100
- To: "Roger L. Costello" <costello@mitre.org>
- Cc: xmlschema-dev@w3.org
"Roger L. Costello" <costello@mitre.org> writes:
> Subject: Is it legal for a schema to reference a
> component in another namespace, when there
> is no <import> element at the top of the
> schema?
>
> I have observed that XSV allows you to create a
> schema which contains references to components in
> other namespaces, even though there is no <import>
> element. Consider the following schema.
>
> weather-station.xsd
> ----------------------------------------------------
> <?xml version="1.0"?>
> <xsd:schema xmlns:xsd="http://www.w3.org/2000/10/XMLSchema"
> targetNamespace="http://www.weather-station.org"
> xmlns="http://www.weather-station.org"
> xmlns:s="http://www.sensor.org"
> elementFormDefault="qualified">
> <xsd:element name="weather-station">
> <xsd:complexType>
> <xsd:sequence>
> <xsd:element name="sensor" type="s:sensor_type"
> maxOccurs="unbounded"/>
> </xsd:sequence>
> </xsd:complexType>
> </xsd:element>
> </xsd:schema>
> ----------------------------------------------------
>
> Note that the "sensor" element references a
> sensor_type which is in another namespace, and note
> that there is no <import> element.
>
> All the other schema validators that I tested
> (xerces, oracle, XML Spy) do not accept this schema.
They are right, XSV is wrong. This is _not_ a "you can wait until
runtime" issue. See QName resolution (Schema Document) [1], the last
clause:
"[the QName's] ·namespace name· is either the target namespace of the schema
document containing the ·QName· or that schema document contains an
<import> element information item the ·actual value· of whose
namespace [attribute] is identical to that ·namespace name·."
ht
[1] http://www.w3.org/TR/xmlschema-1/#src-resolve
--
Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
W3C Fellow 1999--2001, part-time member of W3C Team
2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
URL: http://www.ltg.ed.ac.uk/~ht/
Received on Monday, 7 May 2001 07:18:18 UTC