This book describesthe basics of W3C XML Schema (XSD) language, focusing primarily on 1.1 versionof the XSD language. XSD 1.1 is a successor of XSD 1.0 language and providesadvanced features for XML document validation. The book starts with describingbasics of XML, and then describes the abstract model on which XSD schemas arebased. It then progressively describes the various XSD language features thatare used to write XSD schema documents ranging from the simple ones to muchadvanced XSD schemas. The book provides complete coverage of every aspect of XSDlanguage, explaining the concepts supported by numerous examples.
There are at least three reasons why standardizing such schemas is useful:- When two groups are preparing to exchange informationusing XML documents, a schema gives them a way to agree on what the structureof the documents is to be.
- Because XML schemas are machine-processable and capturedin a standard form, tools can be built to help build XML documentsautomatically, perhaps by extracting information from databases, or to automaticallygenerate input forms to be presented to users. Similar tools can be used toautomatically extract XML information into databases, program APIs, orspreadsheets.
- When documents are generated or received through anetwork, validators can be used to check automatically that the rules have beenfollowed.
The W3C XML Schema language allows us to document the nestingstructure of the elements and attributes in valid documents. It alsostandardizes types such as integer, decimal, or date that apply to the contentof individual attributes or elements.
