XML

What is XML?
XML, Extensible Markup Language, is an open, text based markup language that provides structural and semantic information to data. XML is a metalanguage that can be used to create other language. It is used to structure and describe data that can be understood by other applications. Using XML, we can separate the user interface from data.

Features of XML ?
XML is a generalized markup language that means one can define his/her own tag sets.A valid XML document contains rules and is self-describing.The rules that are found in DTD allow the documents to be validated.


Describe the logical structure of XML.
XML documents comprise of declaration, elements and comments

XML Declaration
It identifies the version to which XML conforms


Document Type Declaration
It consists of markup code that indicates grammar rules or Document Type Definition (DTD) for the particular class of document.

This statement tells the XML processor that the document is of the class Car that conforms the rules specified in the DTD "cr.dtd".

Document element
The document element contains data of an XML document.


Why is XML so popular?
Due to the following advantages of using XML, it has become popular:
It supports Unicode. Therefore documents written in any human language can be communicated.
Data structures: records, lists and trees can be represented using XML.
Its format describes structure, field names and their specific values too. Its therefore called self-documenting.
Its syntax and parsing requirements make the necessary parsing algorithms very simple, efficient, and consistent.
It can be used as a document storage and processing format.
It is platform-independent.