XML Schema Complete Reference, The

6.2. Namespaces

Specifying namespaces, default namespaces, and a target namespace takes only a few lines of code in an XML schema document, yet namespaces seem to be one of the most confusing aspects when learning about XML schemas. This section presents an overview of namespaces, including a discussion of how an XML schema applies namespaces. Chapter 3 presents a thorough discussion of namespaces.

With the exception of anonymous schema components (see Section 1.3), all schema components have a name. Each name nominally belongs to a namespace. Many schemas explicitly have no namespace. A schema specifies the value of a namespace as a URI, although the URI does not have to exist (or be accessible to the XML validator).

Although all the components ...