XQuery

Namespaces and XQuery

Now that you have seen how namespaces are used in XML documents, let's look at how they are used in queries. Namespace-qualified names are used in queries in a number of ways:

• The input documents may contain elements and attributes that are in one or more namespaces.

• The query may construct new elements and attributes that are in one or more namespaces.

• The functions that are declared and/or called in a query have qualified names. This includes user-defined functions and XQuery built-in functions.

• The types used in a query have qualified names that are used, for example, in function signatures and in the constructors that create new values of that type.

  • Built-in types are in the XML Schema Namespace, and are conventionally prefixed with xs:.

  • User-defined types are in the target namespace of the schema document in which they are defined.

• The variables used in a query have qualified names. Many variables will have no namespace and no prefix, but the names are still considered qualified names.