An overview of XML Schema

The structure of an XML document is represented by an XML schema. An XML schema is also an XML document in the namespace http://www.w3.org/2001/XMLSchema.

Root element

The root element in a schema is schema. The schema namespace is specified in the root element with the declaration xmlns:xs=http://www.w3.org/2001/XMLSchema. A prefix other than xs may be used, such as xsd. A schema element may have attributes targetNamespace, version, attributeFormDefault, and elementFormDefault.

• targetNamespace specifies the namespace described in the schema. "An XML namespace is a collection of names, identified by a URI reference, which are used in XML documents as element types and attribute names." (http://www.w3.org/TR/1999/REC-xml-names-19990114/)

• elementFormDefault and attributeFormDefault specify whether elements and attributes in the targetNamespace are required to be qualified by default.

A qualified name consists of a prefix that is mapped to a namespace URI followed...