XML schema language: taking XML to the next level

Schemas add data typing and inheritance features, giving XML the sophistication required to create enterprise-class business applications. The XML schema language describes the legal structure, content, and constraints of XML documents. The XML schema language provides the necessary framework for creating XML documents by specifying the valid structure, constraints, and data types for the various elements and attributes of an XML document. Schema language provides enhanced as well as more comprehensive and powerful features than a document type definition (DTD). The XML schema language provides the rich data typing associated with ordinary programming languages. The W3C XML schema specification defines several different built-in data types, such as string, integer, Boolean, date, and time, among others. The specification also provides the capability for defining new types. Developers can use these built-in as well as user-defined data types to effectively define and constrain XML document attributes and element values.