The report schema, report.xsd, makes
use of the simple type xipo:SKU that is defined in another schema,
and in another target namespace. Recall that we used include so
that the schema in ipo.xsd could make
use of definitions and declarations from address.xsd. We
cannot use include here
because it can only pull in definitions and declarations from a schema whose
target namespace is the same as the including schema's target namespace. Hence,
the include
element does not identify a namespace (although it does require a schemaLocation).
The import mechanism that we describe in this section is an important mechanism
that enables schema components from different target namespaces to be used
together, and hence enables the schema validation of instance content defined
across multiple namespaces.
To import the type SKU and
use it in the report schema, we identify the namespace in which SKU
is defined, and associate that namespace with a prefix for use in the report
schema. Concretely, we use the import
element to identify SKU's target namespace,
http://www.example.com/IPO, and we associate the namespace with the
prefix xipo using a standard namespace declaration. The simple type
SKU, defined in the namespace
http://www.example.com/IPO, may then be referenced as
xipo:SKU in any of the report schema's definitions and
declarations.
Currently, the default namespace is
xmlns="http://www.w3.org/2001/XMLSchema". If we make soap the default
namespace, then we will have to start qualifying types from the above namespace
explicitly, e.g., xsd:nonNegativeInteger, instead of nonNegativeInteger. I don't
see why we should make such change now.
I agree that we should keep our version of envelope.xsd on our web site to
allow existing implementations to continue to refer to it.
Regards,
-Arvola