XSD is an acronym for eXtensible Schema Document. A XML schema is similar to a DTD, but allows more flexibility and precision in structure specification.
This is an XML schema for the XML file above.
The structure of an XSL file is that of a standard XML file, with the addition of some possibly specialised parts. The structure will be as follows.
- XML Prologue
An XSL file is a standard XML file and thus starts with a standard XML prologue.
The top level element of a schema is the xsd:schema element, which must be defined with the namespace prefix pointing to "http://www.w3.org/2001/XMLSchema".
The following code shows a valid schema declaration.