Chapter 34: Working with XML

Overview

One of the most complex features in InDesign is its set of XML features. XML is a structured language that essentially treats document components as data, so you can manage them through a database. The XML tools in InDesign let you treat InDesign documents as sources for XML databases, which are then linked into Web pages, PDF files, CD-ROMs, and so forth. They also let you create InDesign templates into which you flow data from XML files, all formatted and in the proper frames .

The key to XML is the fact that it's extensible. You create the tags, or labels, for various kinds of content (these are called data type descriptions, or DTDs) based on what makes sense for your content. Then you specify what happens to each of the types of labeled content in terms of what's published, how it's presented, and so forth. Compare that to the more rigid HTML and PDF formats, where there are only certain tags available that cannot be changed, and the presentation is fixed based on the label chosen .

XML code is similar to HTML in the sense that there are tags surrounded by angle brackets ( < and > ) and that commands and labels are turned on and off (such as <standardHeader> at the beginning of a header item and </standardHeader> at the end of it. Comments begin with <!-- and end with > , while custom commands and declarations (called processing instructions ) begin with <? and end with ?> . You don't have to understand this level of detail ‚ just keep in mind that there are different codes to look for in examining XML code, if the need arises.

Note ‚  

A DTD may define several types of content that have their own subcontent types and rules. These are called branches . For example, there could be an AuthorInformation branch and a CustomerList branch that both contain tags named Name. You'll need to know which branch text tagged Name should go into, because XML won't know the context.

Cross-Reference ‚  

The use of XML will likely involve assistance from a Webmaster, content engineer, or other programming-savvy person. Page designers might also want to read XML For Dummies , 3rd Edition, by Ed Tittel (Wiley Publishing, Inc.). The InDesign CS Bible limits itself to an overview of InDesign XML functions and is no substitute for a thorough understanding of XML.