Harnessing the Power of XML For Your Business

You can't avoid hearing about XML (Extensible Markup Language). Sometimes it seems like everybody is talking about it. Trade journals, technical web sites and business magazines are full of references to this new technology. There's so much hype about XML that sometimes it's difficult to get a clear picture of just how this technology can be harnessed to achieve useful and measureable business objectives.

This article will cut through some of that hype by providing a concise description of what XML is, as well as showing two of the primary ways that it can be useful to businesses.

What is XML?

In practical terms, XML is a language for representing content in a structured manner. Like HTML, the language in which web pages are created, XML is a markup language. However, XML differs from HTML in that it is what is known as a metalanguage, or a language for creating other languages.

This sounds complicated, so let's put it in perspective. HTML consists of a finite set of element types, or tags, that can be used to record information about content. These tags are referred to as markup. For example, HTML tags can be used to indicate that a web browser should display some text in boldface, as shown below:

<b>This displays as bold on a web page.</b>

Since HTML consists of a finite set of tags, it stands to reason that it has limitations in representing content. As an example, a web page may contain a phone number, but there's no way in HTML to indicate what the content means. With HTML, a phone number can be displayed in a particular font, in boldface or in a selected color, but there's no way to explicitly state that this piece of information is a phone number.

Unlike HTML, XML lets you define your own markup elements. Thus, you can have tags that have meaning within a designated knowledge area. XML will alow you to define a <phone_number> tag to mark phone numbers within your documents. Representing content in XML thus becomes a data modeling activity, much akin to relational database design.

Another key feature of XML is that it encourages the separation of content and presentation logic. The idea is that XML documents will contain content and tags that describe the meaning of the content. Presentation logic is extracted into a style sheet, a separate file that describes how the elements of an XML document should be displayed.

How Can XML Be Useful to Businesses?

There are two primary ways in which XML can be useful to businesses:

  • Content Reuse
  • Communication

Content is a valuable commodity, and leveraging content in different ways can provide significant advantages for companies. XML facilitates the reuse of content.

As an example, consider a newspaper that stores its news articles in XML. The documents will contain tags that describe the meaning of the content, such as <headline>, <byline>, etc. Presentation logic will exist in a separate style sheet. This means that the newspaper company could have separate style sheets to display an XML document in print media and on the web. The same news story, but used in two different ways. The same content could also be easily reused in newsletters, email marketing campaigns or news feeds to other companies.

XML also represents a valuable communication medium. The language promotes the structured representation of content, with data elements that are meaningful within a specified knowledge domain. This means one company can effectively provide content to other companies, with no ambiguity in the meaning of the information.

Furthermore, since XML is a standard language, there are a wide variety of tools available for processing and manipulating XML content. XML thus offers significant advantages over proprietary data dissemination methods.


David Keener By dkeener on Sunday, June 20, 2010 at 12:51 AM EST

This was originally published on the Guident web site. Guident is a small contracting firm, serving primarily the government, based in Herndon, VA. I worked there during the early part of the Internet boom, from 1999 to 2000.

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