The Essential Guide to XML Technologies

Ron Turner, 2002. Upper Saddle River, NJ: Prentice Hall PTR. [ISBN 0-13-065565-1. 385 pages, including index. $34.99 USD (softcover).]

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Ron Turner's The essential guide to XML technologies is basically an XML briefing for IT managers, nontechnical professionals, and business decision makers. Turner presents his material in three parts. The first part covers the major themes for nontechnical readers, addressing XML as knowledge and as exposed content. The second part is more technical, with descriptions of XML core technologies; and the third part presents XML case studies.

In Part I, the author briefly describes how XML originated from SGML as a powerful metalanguage. Because SGML is not as user-friendly, Turner urges readers to use XML as a building block for constructing more powerful markup languages. To illustrate his point, he has provided an excellent example of a news reporting information distribution workflow within the journalism profession. Here, Turner presents an outstanding example of separation of internal structure from its final appearance, which is the heart of markup. The reader is shown how well-structured information can be transformed into hierarchical XML data and liberated from the presentation layer when XML tools and programs are applied to the data to perform various operations such as edit, store, locate, manage, exchange, transform, and deliver. Noteworthy is Turner's idea of using XML to digitize documents leveraging its structural and styling information, and then reconstructing it to its original form after transmission.

The author provides in Part I an excellent analogy between XML and natural languages. The XML Schema is like the grammar in any natural language. To understand a different natural language, you use translators. Equivalently, for XML-based business and industry applications, the communication or transaction must include an XML translation: a grammar-to-grammar conversion of data. Because of XML's built-in transformation capability, IT managers can be assured of the portability of XML and its reusability in a wide variety of applications. Knowledge is considered only in terms of the actual stored content. The best part of XML is that you can make the XML content "smart" by letting the XML markup encapsulate and convey additional layers of knowledge. Once this XML markup-borne knowledge is recognized, it can be used to express logical relationships among items of content.

Turner provides in Part II a quick primer about various technical aspects of core areas of XML. Within nine chapters, he touches on most of the important features used in XML technology. However, the explanations are brief and to the point. These pages make a good reference to use to quickly understand the terms and terminology used in XML. These chapters provide the necessary knowledge base for IT managers and nontechnical people to understand and speak the language of XML. The author explains the usual XML concepts of elements, attributes, entities, Document Type Definitions, XML Schema, XML namespaces, XPath, translation, XLink, XPointer, and other XML-related topics. He provides enough background information to show that XML is both a recommendation and a standard by itself.

In Part III, readers get a chance to gain experience in applying the power of XML in real-life examples. However, readers will find this a disappointing section. The author has chosen five example applications to demonstrate how XML is a promising technology and can be applied in the fields of manufacturing, business reporting, security, law, and wireless applications. He misses the big picture by not showing how XML can best be adopted within the more promising areas of e-commerce, printing, publishing, and channel distribution.

Turner provides inadequate arguments for the necessity for XML in several examples in Part III. For instance, he appears to have simply dumped some recommendations from the legal community into the book to explain how XML can be used in legal documents. Similarly, drawing parallels between a bill of materials in manufacturing and an XML hierarchical structure, as Turner describes, won't necessarily convince management of the wisdom of adopting XML in manufacturing. Turner presents a justification to view Extensible Business Reporting Language (XBRL) not as a risk but as best practice in the accounting, financial, and federal government domains. The IT community will not convince these giants to use XBRL just by throwing in one sample report and an abstract of the XBRL specification. Rather, a simple but practical example of converting 1040 Forms into various accounting reports using an XML Schema taxonomy would have been more appropriate. Also, the examples and text used to describe how XML is best suited for security applications using encryption and digital signatures are also too elementary, as is the chapter on how XML is used in the Wireless Markup Language and the Wireless Application Protocol, providing basic and overly trivial information.

Although Turner presses some weak arguments in Part III, overall, the book is well written and provides ample insight into adopting XML as a core technology for various industrial and commercial applications. Its goal is mainly to introduce XML briefings to nontechnical and business decision makers. The book serves its purpose to that extent.

VIVEK VAISHAMPAYAN is an experienced information technology analyst in designing, developing, and testing computer systems. He has more than 15 years' experience in the industry and has taught courses in HTML, XML, and Java-Script. He has reviewed books on quality assurance and software development.