What is XML, and Why Should You Care?--McIlroy

If you've been following the latest developments in the world of electronic publishing, you've probably come across the abbreviation "XML" (short for eXtended Markup Language). If you've seen it, you're probably confused about it. Most people are—it's very complicated, and there's a lot of imprecise and overly technical information out there. If you haven't heard of XML before, well, I guess you just did. Let's take a look at what XML is, and why it might matter to printers and publishers.

Style Sheets
Do you know style sheets? We've had them for years now in our desktop applications, from Microsoft Word to PageMaker to QuarkXPress. Style sheets are used to simplify the process of formatting text. See that sub-heading just above? It says "Style Sheets" and it's in bold text. If I were working in Word and wanted to change the format of that sub-heading and all the other ones in this article to bold-italic, I'd have two choices. The hard way would be to do it manually: Select each one, and change the format on each from bold to bold-italic. The easy way is to assign a "style" to each one, let's say a style called . Then I can just use the Style commands in Word to change the appearance of to bold-italic. All of my sub-headings would change at once.

If I didn't like the look of bold-italic, I could change back to bold, or to italic, until I found an appearance that I liked. It's a little more upfront work, but it gives users a lot of power and flexibility later in the process.

Power of a Database
Now let's think about databases for a moment. When you set up a database, every field receives a name. If it's a contact database, you'd create a named field for each piece of data. The first field could be where you define whether the person is "Mr.," "Ms.," "Dr." and so on. The second field could be , the third and the fourth . When it's time to print out a mailing list, you'd specify the print order: