XML (abbreviation for "eXtensible Markup Language") is a subset of SGML (Standard Generalized Markup Language). XML is a structured language that facilitates the standardized representation of format and representation and organization of data in an automated environment, such as the use of a browser on a web page.
XML is sanctioned by the World Wide Web Consortium to define a way of transmitting and representing data. XML is designed to transmit data and the meaning of the data. This is accomplished by allowing data "tags" to define both the name of a data element and the format of the data within that element. XML also allows structured relationships to be defined; for example, one named person (subject) in the database might have multiple street addresses and multiple personal contacts, all of which XML is capable of recognizing, revealing, and communicating as "relationships."
XML is easily transmitted as text over the current Internet infrastructure. It is compatible with major Internet transmission protocols and is also highly compressible for faster transmission. Major database vendors and their database applications provide software development "tools" to assist users to develop and use XML more efficiently and productively applications. XML is very developer-friendly, yet ordinary users with no particular XML expertise can make sense of an XML file. The XML standard is designed to be independent of vendor, operating system, source application, destination application, storage medium, and/or transport protocol.