When the first edition of this book was written, XML was a relatively new language but already gaining ground fast and becoming more and more widely used in a vast range of applications. By the time of the second edition, XML had already proven itself to be more than a passing fad, and was in fact being used throughout the industry for an incredibly wide range of uses. With the third edition, it was clear that XML was a mature technology, but more important, it became evident that the XML landscape was dividing into several areas of expertise. Now in this edition, we needed to categorize the increasing number of specifications surrounding XML, which either use XML or provide functionality in addition to the XML core specification.
So what is XML? It’s a markup language, used to describe the structure of data in meaningful ways. Anywhere that data is input/output, stored, or transmitted from one place to another, is a potential fit for XML’s capabilities. Perhaps the most well-known applications are web-related (especially with the latest developments in handheld web access—for which some of the technology is XML-based). However, there are many other non-web-based applications for which XML is useful—for example, as a replacement for (or to complement) traditional databases, or for the transfer of financial information between businesses. News organizations, along with individuals, have also been using XML to distribute syndicated news stories and blog entries.
This book aims to teach you all you need to know about XML—what it is, how it works, what technologies surround it, and how it can best be used in a variety of situations, from simple data transfer to using XML in your web pages. It answers the fundamental questions:
* What is XML?
* How do you use XML?
* How does it work?
* What can you use it for, anyway?
This book is for people who know that it would be a pretty good idea to learn XML but aren’t 100 percent sure why. You’ve heard the hype but haven’t seen enough substance to figure out what XML is and what it can do. You may be using development tools that try to hide the XML behind user interfaces and scripts, but you want to know what is really happening behind the scenes. You may already be somehow involved in web development and probably even know the basics of HTML, although neither of these qualifications is absolutely necessary for this book.
What you don’t need is knowledge of markup languages in general. This book assumes that you’re new to the concept of markup languages, and we have structured it in a way that should make sense to the beginner and yet quickly bring you to XML expert status.
The word “Beginning” in the title refers to the style of the book, rather than the reader’s experience level. There are two types of beginner for whom this book is ideal:
* Programmers who are already familiar with some web programming or data exchange techniques. Programmers in this category will already understand some of the concepts discussed here, but you will learn how you can incorporate XML technologies to enhance those solutions you currently develop.
* Those working in a programming environment but with no substantial knowledge or experience of web development or data exchange applications. In addition to learning how XML technologies can be applied to such applications, you will be introduced to some new concepts to help you understand how such systems work.
The subjects covered in this book are arranged to take you from novice to expert in as logical a manner as we could. This Fourth Edition is structured in sections based on various areas of XML expertise. Unless you are already using XML, you should start by reading the introduction to XML in Part I. From there, you can quickly jump into specific areas of expertise, or, if you prefer, you can read through the book in order. Keep in mind that there is quite a lot of overlap in XML, and that some of the sections make use of techniques described elsewhere in the book.
* The book begins by explaining what exactly XML is and why the industry felt that a language like this was needed.
* After covering the why, the next logical step is the how, so it shows you how to create well-formed XML.
* Once you understand the whys and hows of XML, you’ll go on to some more advanced things you can do when creating your XML documents, to make them not only well formed, but valid. (And you’ll learn what “valid” really means.)
* After you’re comfortable with XML and have seen it in action, the book unleashes the programmer within and looks at an XML-based programming language that you can use to transform XML documents from one format to another.
* Eventually, you will need to store and retrieve XML information from databases. At this point, you will learn not only the state of the art for XML and databases, but also how to query XML information using an SQL-like syntax called XQuery.
* XML wouldn’t really be useful unless you could write programs to read the data in XML documents and create new XML documents, so we’ll get back to programming and look at a couple of ways that you can do that.
* Understanding how to program and use XML within your own business is one thing, but sending that information to a business partner or publishing it to the Internet is another. You’ll learn about technologies that use XML that enable you to send messages across the Internet, publish information, and discover services that provide information.
* Since you have all of this data in XML format, it would be great if you could easily display it to people, and it turns out you can. You’ll see an XML version of HTML called XHTML. You’ll also look at a technology you may already be using in conjunction with HTML documents called CSS. CSS enables you to add visual styles to your XML documents. In addition, you’ll learn how to design stunning graphics and make interactive forms using XML.
* Finally, the book ends with a case study, which should help to give you ideas about how XML can be used in real-life situations, and which could be used in your own applications.
This book builds on the strengths of the earlier editions, and provides new material to reflect the changes in the XML landscape—notably XQuery, RSS and Atom, and AJAX. Updates have been made to reflect the most recent versions of specifications and best practices throughout the book. In addition to the many changes, each chapter has a set of exercise questions to test your understanding of the material. Possible solutions to these questions appear in Appendix A.
Part I: Introduction: The introduction is where most readers should begin. The first three chapters introduce some of the goals of XML as well as the specific rules for constructing XML. Once you have read this part you should be able to read and create your own XML documents.
Chapter 1: What Is XML?: This chapter cover some basic concepts, introducing the fact that XML is a markup language (a bit like HTML) whereby you can define your own elements, tags, and attributes (known as a vocabulary). You’ll see that tags have no presentation meaning—they’re just a way to describe the structure of the data.
Chapter 2: Well-Formed XML: In addition to explaining what well-formed XML is, we offer a look at the rules that exist (the XML 1.0 and 1.1 Recommendations) for naming and structuring elements—you need to comply with these rules in order to produce well-formed XML.
Chapter 3: XML Namespaces: Because tags can be made up, you need to avoid name conflicts when sharing documents. Namespaces provide a way to uniquely identify a group of tags, using a URI. This chapter explains how to use namespaces.
Part II: Validation: In addition to the well-formedness rules you learn in Part I, you will most likely want to learn how to create and use different XML vocabularies. This Part introduces you to DTDs, XML Schemas, and RELAX NG: three languages that define custom XML vocabularies. It also shows you how to utilize these definitions to validate your XML documents.
Chapter 4: Document Type Definitions: You can specify how an XML document should be structured, and even provide default values, using Document Type Definitions (DTDs). If XML conforms to the associated DTD, it is known as valid XML. This chapter covers the basics of using DTDs.
Chapter 5: XML Schemas: XML Schemas, like DTDs, enable you to define how a document should be structured. In additio...
Amazon.com Review: Beginning XML provides a complete course in the Extensible Markup Language (XML) with an unusually gradual learning curve. In fact, the introduction states that the book is "for people who know that it would be a pretty good idea to learn the language, but aren't 100 percent sure why." Despite its recognition of the fuzziness of readers' understanding of the technology, the book delivers a rather comprehensive study of XML.
Very little space is wasted detailing the history of XML and its relation to SGML, as is the case in many other titles. The argument for the importance of XML is made quickly, and the basics of well-formed syntax are tackled right off. One notable distinction of this book is its excellent coverage of related technologies, such as cascading style sheets (CSS) and relational databases.
In addition to discussing the crucial companion standards to the core XML language (DTDs, XSL, and XSLT), the book adds a nice perspective to the broad range of applications in which XML can play a role. One section, "Other Uses for XML," illustrates how XML can be used to serialize object models, creating stateless objects and utilizing the Resource Description Framework (RDF). Case studies on--among other things--how XML can be used to build discussion groups, and provide B2B data transfer, round out the text. This book is perfect for Web programmers who are turning their attention to XML for the first time. It imparts a solid understanding of the XML forest and XML trees. --Stephen W. Plain
A Must Buy This book is very concise and it tells a lot about the subject including other topics such as XSLT, RSS, and many other web technologies related to XML. Would highly suggest buying.
Excellent XML book I'm currently reading this book and enjoying it very much. You probably would understand it more if you are already a programmer. But I think it's good for non-programmers as well. Covers a lot of the new technologies that are using XML, which is very useful.
Great XML Reference Book. Other than the fact that you can tell that the book was written by 5 different guys because of the the difference in writing styles between chapters, overall it is packed full of information and a handy reference.
Choppy and poorly written (I don't have time for a full review right now,so I will write a few comments and try to add to them.)
I knew very little about XML, so this sounded promising. As of Chapter 8, my general comments are:
1. The teaching structure is often murky. At many spots, the authors don't seem to grasp what a beginner needs to know first in order to go to the next step. This makes the material unnecessarily difficult and confusing.
2. Instead of one example page, for some reason the authors will sometimes create one XML page to illustrate a point, then create another completely different page to illustrate the next point, then go back to the first one for the next point, etc. It's inexplicable. The book would be much easier to follow, and probably easier to write, if they built one XML page from scratch and used/modified it throughout the book.
3. There are too many editorial screw-ups, such as "Figures" that are labeled incorrectly or don't exist -- that is, the text will say "see Figure 7 for the output" and Figure 7 will be the wrong one. I really have no patience with expensive books that don't bother to pay for one thorough copy-editing.
I am currently on Chapter 8 (XSLT), one of the worst-written ones. After a completely unnecessary discussion about "procedural" versus "declarative" programming (I imagine every reader is at least basically familiar with css, and if not, it is hardly difficult to understand "declarative" programming), the book just starts throwing XLST terms at you, with no foundation as to what they are doing or why. I finally gave up and pulled up the online W3C tutorial. This tutorial is free, covers most of the material, and is well-organized and easy to understand. Teaching in logical order isn't that hard.
There is a ton of good information in "Beginning XML", and the information on how to find, install, and use software such as Saxon and Schematron is invaluable. It is a shame that the authors didn't take the time to actually give the book to a few XML novices and then rewrite it as the introductory text it is supposed to be. The poorly organized writing at least doubles, and often triples, the time, energy, and painful confusion needed to learn the material.
Fairly good, but not practical for non-Microsoft users I am taking an XML class at the University using this book as the required course text. The authors do a good job at highlighting the key technologies, and the examples and tutorials significantly enhance the material. I enjoy the straight-forward manner with which Hunter and his friends explains what the example code in the book does. My only disappointment is that the book does not explain in enough detail how to use XML technologies on non-Microsoft systems. I believe a greater emphasis on Java and non-VB/ASP/.NET can extend the benefits this book otherwise offers.
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