XML, otherwise known as eXtensible Mark Up language is the latest buzz word on the internet.
- Why is this? XML is a meta language, meaning a language which describes data. Like HTML, it is a sub set of SGML (Standardized General Mark Up Language) but unlike HTML it is infinitely extensible.
- What do we mean by this? Well, HTML has a fixed number of tags and for the most part, these tags define what a page of text will look like in your browser - will it be bold, italic, a paragraph, a heading etc. This tells you nothing about the data the page contains. In XML, there is no limit to the number of tags and each tag describes the data it contains. So, if I was summarizing these book details in XML, I would have an pair of tags which would contain the ISBN number of the book, a pair of tags, an pair of tags and so on.
- So what, you may ask? So the possibilities this opens up for identifying and sorting data are huge. If I had a whole pile of individual title information sheets, and I wanted to produce a single document which listed all the ISBNS, all the prices etc, I would just sort on the specific XML tags. If I turned a book into XML - the Bible, the Koran and the works of Shakespeare have already been done - and then wanted details of a specific subject I would search for the XML tagged data.
XML is a user friendly version of SGML which will make the management of huge sets of on-line documentation much easier. It's a language which describes data, making it much easier to find and sort by the data type you require. It opens up the opportunity for industry groups, like the health care and automotive industries to create their own specific languages for the interchange of data. It speeds up the transfer of data from a database on the server to an application on the client - check out the Microsoft auction demo on the MS XML page. It has immense potential, and, crucially the support of both the major browser companies.