What is XML?

XML (Extensible markup language) is all about describing data. Below is a XML which describes book store.

<?xml version=”1.0″ encoding=”ISO-8859-1″?>
<book>
<php>php by pcds infotech</php>
<java>Jave j2ee by pcds infotec</java>

An XML tag is not something predefined but it is something you have to define according to your needs. For instance in the above example of books all tags are defined according to business needs. The XML document is self explanatory, any one can easily understand looking at the XML data what exactly it means.