Re: multiple namespaces

• From: Andrew Welch <andrew.j.welch@gmail.com>
• Date: Mon, 23 Apr 2007 16:05:47 +0100
• To: "noah_mendelsohn@us.ibm.com" <noah_mendelsohn@us.ibm.com>
• Cc: xmlschema-dev@w3.org
• Message-ID: <74a894af0704230805m535b3b40v96d248f569b294d8@mail.gmail.com>

Ok here's a complete example:

<ns1:root xmlns:ns1="firstNamespace" xmlns:ns2="secondNamespace">
	<ns1:foo>some text</ns1:foo>
	<ns2:bar>some <ns1:foo> more </ns1:foo> text</ns2:bar>
</ns1:root>

The keys points here are:

- there are two namespaces
- each namespace contains elements in the other namespace

In order to model this I created two schema documents ns1.xsd and
ns2.xsd which import each other:

==== ns1.xsd ====

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified" attributeFormDefault="unqualified"
    targetNamespace="firstNamespace"
	xmlns:ns1="firstNamespace"
	xmlns:ns2="secondNamespace">
	
	<xs:import namespace="secondNamespace" schemaLocation="ns2.xsd"/>
	
	<xs:element name="root" type="ns1:root"/>
	<xs:element name="foo" type="ns1:non-empty-string"/>
	
	<xs:complexType name="root">
		<xs:sequence>
			<xs:element ref="ns1:foo"/>
			<xs:element ref="ns2:bar"/>
		</xs:sequence>
	</xs:complexType>
	
	<xs:simpleType name="non-empty-string">		
		<xs:restriction base="xs:string">		
			<xs:minLength value="1"/>		
		</xs:restriction>		
    </xs:simpleType>	
</xs:schema>


==== ns2.xsd ====

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified" attributeFormDefault="unqualified"
    targetNamespace="secondNamespace"
	xmlns:ns1="firstNamespace"
	xmlns:ns2="secondNamespace">
	
	<xs:import namespace="firstNamespace" schemaLocation="ns1.xsd"/>
	
	<xs:element name="bar" type="ns2:bar"/>
	
	<xs:group name="various-elements">
		<xs:choice>
			<xs:element ref="ns1:foo" minOccurs="0"/>
			<!-- lots of other elements that can occur in any order -->
		</xs:choice>
	</xs:group>
	
	<xs:complexType name="bar" mixed="true">
		<xs:group ref="ns2:various-elements"/>
	</xs:complexType>
	
</xs:schema>


I'd like any comments on this approach - its seems strange to have
circular imports, and when referencing the simpleType and the group
prefixes are needed - unless as Mike says I add a default namespace,
which I think would make the top of the schema document:

targetNamespace="firstNamespace"
xmlns:ns1="firstNamespace"
xmlns="firstNamespace"

...which is fine but a little non-intuitive at the moment - is there a
preferred approach?

thanks
andrew

Received on Monday, 23 April 2007 15:05:54 UTC