Product Description

Learning the fundamentals of XML might take a programmer a week. Learning how to use XML effectively might take a lifetime. While many books have been written that teach developers how to use the basic syntax of XML, this is the first one that really focuses on how to use XML well. This book is not a tutorial. It is not going to teach you what a tag is or how to write a DTD (Document Type Definition). Instead it's going to tell you when, why, where, and how to use such tools effectively (and equally important when not to use them).Since XML has become a fundamental underpinning of new software systems, it becomes important to ask new questions, not just what XML is, but how does one use it effectively? Which techniques work and which don't? Perhaps most importantly, which techniques appear to work at first but fail to scale as systems are further developed? This book answers these questions. It is not enough to write programs that compile and produce the expected results. It is important to write code that is extensible, legible, and maintainable. XML can be used to produce robust, extensible, maintainable systems.

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Product Details

• Amazon Sales Rank: #311740 in Books
• Published on: 2003-10-02
• Original language: English
• Number of items: 1
• Binding: Paperback
• 336 pages

From the Back Cover

"This is an excellent collection of XML best practices: essential reading for any developer using XML. This book will help you avoid common pitfalls and ensure your XML applications remain practical and interoperable for as long as possible."—Edd Dumbill, Managing Editor, XML.com and Program Chair, XML Europe

"A collection of useful advice about XML and related technologies. Well worth reading before, during, and after XML application development."—Sean McGrath, CTO, Propylon

If you want to become a more effective XML developer, you need this book. You will learn which tools to use when in order to write legible, extensible, maintainable and robust XML code.

Page 36: How do you write DTDs that are independent of namespace prefixes? Page 82: What do parsers reliably report and what don't they? Page 130: Which schema language is the right one for your job? Page 178: Which API should you choose for maximum speed and minimum size? Page 257: What can you do to ensure fast, reliable access to DTDs and schemas without making your document less portable? Page 283: Is XML too verbose for your application?

Elliotte Rusty Harold provides you with 50 practical rules of thumb based on real-world examples and best practices. His engaging writing style is easy to understand and illustrates how you can save development time while improving your XML code. Learn to write XML that is easy to edit, simple to process, and is fully interoperable with other applications and code. Understand how to design and document XML vocabularies so they are both descriptive and extensible. After reading this book, you'll be ready to choose the best tools and APIs for both large-scale and small-scale processing jobs. Elliotte provides you with essential information on building services such as verification, compression, authentication, caching, and content management.

If you want to design, deploy, or build better systems that utilize XML—then buy this book and get going!

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About the Author

Elliotte Rusty Harold is an internationally respected writer, programmer, and educator. He is an Adjunct Professor of Computer Science at Polytechnic University in Brooklyn, where he lectures on Java and object-oriented programming. His Cafe con Leche Web site has become one of the most popular sites for information on XML. In addition, he is the author and coauthor of numerous books, the most recent of which are The XML Bible (John Wiley & Sons, 2001) and XML in a Nutshell (O'Reilly, 2002).

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Excerpt. © Reprinted by permission. All rights reserved.

Learning the fundamentals of XML might take a programmer a week. Learning how to use XML effectively might take a lifetime. While many books have been written that teach developers how to use the basic syntax of XML, this is the first one that really focuses on how to use XML well. This book is not a tutorial. It is not going to teach you what a tag is or how to write a DTD. I assume you know these things. Instead it's going to tell you when, why, where, and how to use such tools effectively (and perhaps equally importantly when not to use them). This book derives directly from my own experiences teaching and writing about XML. Over the last five years. I've written several books and taught numerous introductory courses about XML syntax, APIs, and tools. Increasingly I'm finding that audiences are already familiar with the basics of XML. They know what a tag is, how to validate a document against a DTD, and how to transform a document with an XSLT style sheet. The question of what XML is and why to use it has been sufficiently well evangelized. The essential syntax and rules are reasonably well understood. However, although most developers know what a CDATA section is, they are not sure what to use one for. Although programmers know how to add attribute and child nodes to elements, they are not certain which one to use when.

Since XML has become a fundamental underpinning of new software systems, it becomes important to begin asking new questions, not just what XML is, but how does one use it effectively? Which techniques work and which don't? Perhaps most importantly, which techniques appear to work at first but fail to scale as systems are further developed? When I teach programming at my university, one of the first things I tell my students is that it is not enough to write programs that compile and produce the expected results. It is as important (perhaps more important) to write code that is extensible, legible, and maintainable. XML can be used to produce robust, extensible, maintainable, comprehensible systems or it can be used to create masses of unmaintainable, illegible, fragile, closed code. In the immortal words of Eric Clapton, "It's in the way that you use it." XML is not a programming language. It is a markup language; but it is being successfully used by many programmers. There have been markup languages before, but in the developer community XML is far and away the most successful. However, the newness and unfamiliarity of markup languages have meant that many developers are using it less effectively than they could. Many programmers are hacking together systems that work, but are not as robust, extensible, or portable as XML promises. This is to be expected. Programmers working with XML are pioneers exploring new territory, opening up new vistas in software, and accomplishing things that could not easily be accomplished just a few years ago. However one definition of a pioneer is someone with an arrow in their back, and more than a few XML pioneers have returned from the frontier with arrows in their backs.

Five years after the initial release of XML into the world, certain patterns and antipatterns for the proper design of XML applications are becoming apparent. All of us in the XML community have made mistakes while exploring this new territory, the author of this book prominently among them. However, we've learned from those mistakes, and we're beginning to develop some principles that may help those who follow in our footsteps to avoid making the same mistakes we did. It is time to put up some caution signs in the road. We may not exactly say "Here there be dragons", but we can at least say, "That road is a lot rockier than it looks at first glance, and you might really want to take this slightly less obvious but much smoother path off to the left."

This book is divided into four parts beginning with the lowest layer of XML and gradually working up to the highest:

• Part I covers XML syntax, those aspects of XML that don't really affect the information content of an XML document, but may have large impacts on how easy or hard those documents are to edit and process.
• Part II looks at XML structures, the general organization and annotation of information in an XML document.
• Part III discusses the various techniques and APIs that are available for processing XML with languages such as C++, C#, Java, Python, and Perl and thus local semantics to the labeled structures of XML.
• Part IV explores effective techniques for systems built around XML documents, rather than looking at individual documents in isolation.

Although, this is how I've organized the book, you should be able to begin reading at essentially any chapter. This book makes an excellent bathroom reader. :-) You may wish to read the introduction first, which defines a number of key terms that are used throughout the book, and which are frequently misused or confused. However, after that feel free to pick and choose from the topics as your interest and needs dictate. I've made liberal use of cross-references to throughout to direct you along other paths through the book that may be of interest.

I hope that this book is a beginning, not an end. It's still early in the life of XML, and much remains to be discovered and invented. You may well develop best practices of your own that are not mentioned here. If you do I'd love to hear about them. You may also take issue with some of the principles stated here. I'd like to hear about that too. Discussion of many of the guidelines identified here has taken place on the xml-dev mailing list, and seems likely to continue in the future. If you're interested in further discussion of the issues raised in this book, I recommend you subscribe and participate there. Complete details can be found at http://lists.xml.org/. On the other hand, if you find out and out mistakes in this book (The ID attribute value on p. 87 is missing a closing quote. The word "Cat" is misspelled on p. 46.) you can write me directly at elharo@metalab.unc.edu. I maintain a web page listing known errata for this book, as well as any updates at http://www.cafeconleche.org/books/effectivexml/. I hope this book makes your use of XML both more effective and more enjoyable.

—Elliotte Rusty Harold
elharo@metalab.unc.edu
Brooklyn NY
April 22, 2003

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Customer Reviews

A Maturing and More Sophisticated XML
... Harold has put together an advanced overview of ALL
XML.

A significant part of the value of this book is in Harold's assessment of the various proposed extensions to XML, like the XML Schema language, or the abovementioned XLink and XQuery. XML is still growing rapidly, and there is a real need for various extensions. But there is also a consequent need for
independent comparative assessments of those extensions. For example, if you have a book devoted to XML Schema, it might not even tell you that there are other competing schema languages.

En passant, he gives an unusually clear explanation of the difference between a character set and a character encoding. The former is a mapping of some characters to numbers. The latter is an instantiation of those numbers as an actual numerical storage. Often in other books, you can see the two phrases used interchangeably and imprecisely. By contrast,
throughout this book Harold emphasises a precision of terminology. A priori, if you are into XML, then you need to be precise.

I have one minor quibble. He says that multiple XML documents "can be stored in a single file, though this is unusual in practice." He might have added that one of these instances is instructive. If you have a continuously running program that periodically writes to a log file in XML, then during the writing, for efficiency, you would append XML documents to the file. So notice that at all times, the entire file is not an XML document, because there are no enclosing tags.

The best XML book I've read
Effective XML is a collection of about 50 tips for working with XML. Although XML seems is simple and easy to use, it's also easy to get wrong. I've often scratched your head and wondered why things like XML Schema, for example, just doesn't feel right. But it wasn't until I read Effective XML that I understood what was really awkward with it.

Because the book is so diverse (an amazing feat considering the small page count), it is hard to single out any specific part as being a reason to read the book. The book doesn't just talk about schemas, the infoset, etc..., it digs down and really explains what is good and bad about the technologies and what the best ways to apply them are. All I can say is that I use XML day in and day out and have learned everything I know by trial an error. I've made many mistakes along the way. I've tried my best to learn from them, but Effective XML was the book that made everything click for me. The best part is that the book went well beyond just helping me see my errors. I've already applied some of the ideas to new work I've done recently and have been able to head off some of the problems I would have encountered.


Effective XML is by far the best XML book I've ever read, and quite possibly the best tech book I've read all year. I might even have to add it to my favorite tech books list. If you work with XML to any significant degree, I can't recommend this book highly enough.

I wish the XML Schema working group had a copy per member
This is not a book explaining XML. This is not a book that goes into any depth on XML APIs. It is not a book explaining any one XML format like XSLT, RSS, or XSD.

Instead it is a book on how to work with XML. How to design an XML application to take full advantage of the facilties of XML: schemas, processing instructions, XSL transforms, namespaces. It is all structured to slowly introduce you into the complexities, and deserves to sit up on the bookshelf with Effective C++, Java and Enterprise Java.

If you already know the basics of XML, it is actually quite a good way to learn about some of the more esoteric concepts -from the pragmatic perspective. Too many XML books rant about how wonderful some feature like XML schema's extension stuff is, why XML is the most universal format ever, SOAP and WS-* the best protocol for distributed systems ever, and XQuery everything you need for an XML database.

This book bursts the bubble of hype with rational analysis of what makes sense, and what doesn't. Item 28: Use only what you need, is my favourite: A review of the main XML specs and analysis of what really matters, which comes down to #35, navigate with XPath.

If you are designing an XML schema/system/application, you need this book. If you have to put up with architects telling you about WS-MetadataExchange, WS-Transfer and RDF, you need a copy to roll up and hit them over the head. And, if like me, you are involved in standards bodies that produce XML related things, you need to buy a copy for all the other participants, so that what you produce will actually work.

Remember that XML is a language designed for use by people and machines. The machines have the upper hand. But with this book, and some thinking, you can design XML applications that people can use.