XML – eXtensible Markup Language
A Unicorn InterGlobal White Paper
Shaun Rudderham
Printed March 2000
What is XML eXtensible Markup Language?
XML is a new technology designed for creating Internet/Web applications. XML is used both to present information to people and to enable computer-to-computer (read business-to-business) transactions.
Where did it come from and why?
In 1996 the World Wide Web Consortium (W3C) began developing XML as it was already evident that HTML, which forms the basis for most Web pages, had inherent limitations when it came to describing data. Like HTML, XML is based on SGML – Standard Generalised Markup Language. It is not owned by any particular company, individual or organisation and therefore represents an “open” standard for software developers. It’s important to realise that while XML wasn’t designed to replace HTML, there are new variations appearing very rapidly such as XHTML that may already spell the end for HTML.
How does it work?
XML provides a way to put structured data into text files. By structured data we mean documents, spreadsheets, address books, financial transactions, etc. The word eXtensible means XML allows you to create your own tags (words bracketed by ‘<‘ and ‘>’) and attributes (of the form name=”value”) to describe the information in a document. HTML also uses tags and attributes but these are typically pre-defined and used to describe the presentation of a document. Table 1 shows a few basic examples of HTML and XML tags.
| HTML Tags | Purpose | XML Tags | Purpose |
| <bold> | Display bold text | <prod-name> | store product name |
| <italic> | Display italic text | <prot-price> | store product price |
| <font> | Set the font style | <qty-ordered> | store quantity ordered |
Table 1 – Basic HTML &XML tags
Another important feature of XML is that it provides a simple way to create documents that can easily be presented or published to various forms of electronic and physical media, including PC’s, PDA’s, the latest mobile phones and the good old printed page. Finally, perhaps the most compelling aspect of XML is that it provides a means by which incompatible computer systems can automatically exchange information. This may sound like Utopia or Armageddon, depending on your viewpoint, but it’s now reality. XML has been in use for over two years now and most of the major players are already firm supporters.
What XML can be used for?
- Automating the exchange of information between organisations
- Uploading/downloading data from databases
- Facilitating e-commerce applications that interact with several organizations to serve a customer
- Delivering information to hand-held devices such as PDAs, WebTVs, Mobile Phones, etc
A few other advantages
- it’s free….as it’s a W3C standard there are no licence fees
- platform independence (remember XML files are just text files…)
- there’s a rapidly growing community of developers and organizations providing a wide range of associated products and services
- did I mention it’s free….?
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