Extended Markup Language(XML):-
Extended Markup Language or XML is a language used for exchanging data between applications. XML is not only used on internet but it is also used to simply exchange data between different platforms and applications.
The need for XML is simple. In commercial environments, application need to exchange data/information in order to integrate. Integration has traditionally been very difficult to do and XML together with web service is designed to reduce the difficulties and cost involved in software integration.
The actual structure of the data contained in the XML document is up to the customers and suppliers to decide. Any two parties who wish to exchange data using XML are completely free to decide what the document should look like.
XML is a lot more descriptive and it can be validated against a schema. A schema defines what the XML document or fragment should look like. XML is come out from "Standard General Markup Language(SGML)". In many ways XML is not a language as the name suggests but is rather a set of rules for defining your own markup language that allows the exchange of data.
XML is tag based,i.e, the document is made up of tags that contains data.
The above XML file represents the description of a book.
Beginning VB.NET 2003