About the Authors Tim Converse has written software to recommend neckties, answer questions about space stations, pick value stocks, and make simulated breakfast. He has an M.S. in Computer Science from the University of Chicago, where he taught several programming classes. He is now an engineering manager in the Web search group at Yahoo!. Joyce Park has an M.A. in history from the University of Chicago, and has worked for several Silicon Valley startups including Epinions, KnowNow, and Friendster. She is a co-lead of the Mod-pubsub Open Source project. Clark Morgan is a Web application and educational software developer with more than five years’ experience writing PHP. He works primarily with medical clients and related busi- nesses. Originally from Boston, he now lives and works in Jacksonville, Florida, with his wife and two children. Clark spends entirely too much of his free time reading other people’s com- puter books.
Credits Acquisitions Editor Vice President and Publisher Debra Williams Cauley Joseph B. Wikert Development Editor Executive Editorial Director Sara Shlaer Mary Bednarek Production Editor Project Coordinator Eric Newman April Farling Technical Editors Graphics and Production Specialists Chris Cornell Beth Brooks David Wall Sean Decker Carrie Foster Copy Editor Lauren Goddard C. M. Jones Quality Control Technician Editorial Manager Laura Albert Mary Beth Wakefield Carl William Pierce Vice President & Executive Group Permissions Editor Publisher Carmen Krikorian Richard Swadley Media Development Specialist Vice President and Executive Angela Denny Publisher Bob Ipsen Proofreading and Indexing TECHBOOKS Production Services
To our parents: For their love, for their sacrifices, and for letting us read a lot when we were kids. — Tim Converse and Joyce Park This, my first serious writing effort, is for my lifelong friend Bob, who pointed me inthis direction nearly ten years ago and then had the nerve to suggest I write about it. — Clark Morgan
Preface W elcome to PHP5 and MySQL Bible! Although we’re biased, we believe that the PHP Web-scripting language is the hands-down win- ner in its niche — by far the easiest and most flexible server-side tool for getting great Web sites up and running in a hurry. Although millions of Web programmers worldwide could be wrong, in this particular case, they’re not. MySQL is the most popular open-source database platform, and it is the first choice of many for creating database-backed PHP-driven Web sites As we write this, PHP5 is in its third beta version, and PHP has continued to grow in reach, adoption, and features since we wrote the first two versions of this book.What Is PHP? PHP is an open-source, server-side, HTML-embedded Web-scripting language that is compati- ble with all the major Web servers (most notably Apache). PHP enables you to embed code fragments in normal HTML pages — code that is interpreted as your pages are served up to users. PHP also serves as a “glue” language, making it easy to connect your Web pages to server-side databases.Why PHP? We devote nearly all of Chapter 1 to this question. The short answer is that it’s free, it’s open source, it’s full featured, it’s cross-platform, it’s stable, it’s fast, it’s clearly designed, it’s easy to learn, and it plays well with others.What’s New in This Edition? Although this book has a new title, it is in some sense a third edition. Previous versions were: ✦ PHP 4 Bible. Published in August 2000, covering PHP through version 4.0. ✦ PHP Bible, Second Edition. Published in September 2002, a significantly expanded ver- sion of the first edition, current through PHP 4.2. Our initial plan for this book was to simply reorganize the second edition and bring it up to date with PHP5. We realized, however, that although the previous editions covered PHP/MySQL interaction, we had left readers in the dark about how to create and administer MySQL databases in the first place, and this led to many reader questions. As a result, we decided to beef up the coverage of MySQL and change the title.
x Preface New PHP5 features Although much of PHP4’s functionality survives unchanged in PHP5, there have been some deep changes. Among the ones we cover are: ✦ Zend Engine 2 and the new object model, with support for private/protected members, abstract classes, and interfaces ✦ PHP5’s completely reworked XML support, built around libmxl2 ✦ Exceptions and exception handling MySQL coverage We now cover MySQL 4.0 installation, database design, and administration, including back- ups, replication, and recovery. As with previous editions, we devote much of the book to techniques for writing MySQL-backed PHP applications. Other new material In addition to MySQL- and PHP5-specific features, we’ve added: ✦ Improved coverage of databases other than MySQL (Oracle, PostgreSQL, and the PEAR database interaction layer) ✦ The PEAR code repository ✦ A chapter on integrating PHP and Java ✦ Separate chapters on error-handling and debugging techniques Finally, we reorganized the entire book, pushing more advanced topics toward the end, to give beginners an easier ramp up. Who wrote the book? The first two editions were by Converse and Park, with a guest chapter by Dustin Mitchell and tech editing by Richard Lynch. For this version, Clark Morgan took on much of the revi- sion work, with help by Converse and Park as well as by David Wall and Chris Cornell, who also contributed chapters and did technical editing. Whom This Book Is For This book is for anyone who wants to build Web sites that exhibit more complex behavior than is possible with static HTML pages. Within that population, we had the following three particular audiences in mind: ✦ Web site designers who know HTML and want to move into creating dynamic Web sites ✦ Experienced programmers (in C, Java, Perl, and so on) without Web experience who want to quickly get up to speed in server-side Web programming ✦ Web programmers who have used other server-side technologies (Active Server Pages, Java Server Pages, or ColdFusion, for example) and want to upgrade or simply add another tool to their kit.
Preface xi We assume that the reader is familiar with HTML and has a basic knowledge of the workings of the Web, but we do not assume any programming experience beyond that. To help save time for more experienced programmers, we include a number of notes and asides that com- pare PHP with other languages and indicate which chapters and sections may be safely skipped. Finally, see our appendixes, which offer specific advice for C programmers, ASP coders, and pure-HTML designers.This Book Is Not the Manual The PHP Documentation Group has assembled a great online manual, located at www.php.net and served up (of course) by PHP. This book is not that manual or even a substitute for it. We see the book as complementary to the manual and expect that you will want to go back and forth between them to some extent. In general, you’ll find the online manual to be very comprehensive, covering all aspects and functions of the language, but inevitably without a great amount of depth in any one topic. By contrast, we have the leisure of zeroing in on aspects that are most used or least understood and give background, explanations, and lengthy examples.How the Book Is Organized This book is divided into five parts, as the following sections describe. Part I: PHP: The Basics This part is intended to bring the reader up to speed on the most essential aspects of PHP, with complexities and abstruse features deferred to later Parts. ✦ Chapters 1 through 4 provide an introduction to PHP and tell you what you need to know to get started. ✦ Chapters 5 through 10 are a guide to the most central facets of PHP (with the exception of database interaction): the syntax, the datatypes, and the most basic built-in functions. ✦ Chapter 11 is a guide to the most common pitfalls of PHP programming. Part II: PHP and MySQL Part II is devoted both to MySQL and to PHP’s interaction with MySQL. ✦ Chapters 12 and 13 provide a general orientation to Web programming with SQL databases, including advice on how to choose the database system that is right for you. ✦ Chapter 14 covers installation and administration of MySQL databases, and Chapter 15 is devoted to PHP functions for MySQL. ✦ Chapters 16 and 17 are detailed, code-rich case studies of PHP/MySQL interactions. ✦ Chapters 18 and 19 provide tips and gotchas specific to PHP/MySQL work.
Preface xiii If included in a code context, italics indicate portions that should be filled in appropriately, as opposed to being taken literally. In normal text, an italicized term means a possibly unfamiliar word or phrase. What the Icons Mean Icons similar to the following example are sprinkled liberally throughout the book. Their pur- pose is to visually set off certain important kinds of information. Tip Tip icons indicate PHP tricks or techniques that may not be obvious and that enable you to accomplish something more easily or efficiently. Note Note icons usually provide additional information or clarification but can be safely ignored if you are not already interested. Notes in this book are often audience-specific, targeted to people who already know a particular programming language or technology. Caution Caution icons indicate something that does not work as advertised, something that is easily misunderstood or misused, or anything else that can get programmers into trouble.Cross- We use this icon whenever related information is in a different chapter or section.Reference The Web Site and Sample Code All the sample code from the book, as well as supplementary material we develop after press time, can be found at our Web site at www.troutworks.com/phpbook. You can also find the sample code at www.wiley.com/compbooks/converse. We want to hear from you! Please send us e-mail at firstname.lastname@example.org with com- ments, errata, kudos, flames, or any other communication that you care to send our way.
Acknowledgments T his project began out of a conversation with Debra Williams Cauley, our acquisitions edi- tor at Wiley. She managed the project, found additional contributors, and maintained a sense of humor as she insulated naive first-time authors from the harsh realities of the pub- lishing business. (For the next two editions, she insulated naive second-time and third-time authors, respectively.) Sara Shlaer was the development editor who coordinated everything among the contributors, stayed on us to make the project not quite as late as it would otherwise have been, and cri- tiqued our drafts in detail, making some great saves along the way. Clark Morgan did the majority of the revision of previous material. David Wall and Chris Cornell each wrote novel chapters, revised previous chapters, and served as technical reviewers. Thanks to the Webmasters of the PHP team for permission to reproduce a graph of PHP usage; the folks at Zend for permission to use screenshots of their Zend Studio product; Amazon.com for data in the Web services chapter; KnowNow, Inc., for permission to excerpt code originally owned by them; Mimi Yin for her fabo design work; Alex Selkirk for permis- sion to reproduce material from Opencortex.org; Tim Perdue for inspiration; Hoang Nguyen for debugging help; and Jeff Barr of Syndic8.com for timely aid. Our obvious thanks go to everyone who created PHP itself (Rasmus Lerdorf, Zeev Suraski, Andi Gutmans, Thies Arntzen, Stig Bakken, Sascha Schumann, Andrei Zmievski, Sterling Hughes, Wez Furlong, George Schlossnagle, Dan Libby, Sam Ruby, and a host of other contributors), the peo- ple who have documented PHP (Stig Bakken, Alexander Aulbach, Egon Schmid, Lars Torben Wilson, Jim Winstead, and others), and everyone on the PHP mailing list. Special thanks to Rasmus, Sascha, and Richard Lynch for mailing-list answers to our own questions. Finally, both Converse and Park would like thank their spouses for their support while this book was being written and revised. In a very literal sense, we couldn’t have done it without them.