Question

Is this possible to write xsds for the following xml:

<list add:type="single" view:type="multi"/>

where add and view point to different schemas? I will then use schema name to filter required attribute value.

Answer 1

You will use three schema documents to do this.

• Schema document 1 will have a targetNamespace for add’s namespace and will declare a global attribute named “type”.
• Schema document 2 will have a targetNamespace for view’s namespace and will declare a global attribute named “type”.
• Schema document 3 will import the two namespaces. It will also declare a complexType that has two attributes defined using attribute references to “add:type” and “view:type”. Element “list” will be of that type. You will be sure to include xmlns:add=”…” and xmlns:view=”…” namespace declarations in the scope of the attribute definitions.

Basically, any time you want elements or attributes from other namespaces, you have another schema document with a targetNamespace of that namespace. There, the elements or attributes for that namespace are declared globally. Then, when you wish to use these attributes or elements in some other schema document you 1) import the namespace (xs:import) 2) declare a ns prefix for the namespace and 3) use ref=”nsprefix:attr_or_elem_name” to refer to the attribute or element.