3537-4 FM.f.qc 12/15/00 15:31 Page i MySQL/PHP Database Applications 3537-4 FM.f.qc 12/15/00 15:31 Page ii 3537-4 FM.f.qc 12/15/00 15:31 Page iii MySQL/PHP Database Applications Jay Greenspan and Brad Bulger M&T Books An imprint of IDGBooks Worldwide, Inc. Foster City, CA (cid:2) Chicago, IL (cid:2) Indianapolis, IN (cid:2) New York, NY 3537-4 FM.f.qc 12/15/00 15:31 Page iv MySQL/PHP Database Applications Service department at 800-762-2974. For reseller Published by information, including discounts and premium sales, M&T Books please call our Reseller Customer Service department An imprint of IDG Books Worldwide, Inc. at 800-434-3422. 919 E. Hillsdale Blvd., Suite 400 For information on where to purchase IDG Books Foster City, CA 94404 Worldwide’s books outside the U.S., please contact our www.idgbooks.com(IDG Books Worldwide Web site) International Sales department at 317-572-3993 or fax Copyright ©2001 IDG Books Worldwide, Inc. All rights 317-572-4002. reserved. 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IDG Books Worldwide, Inc. from International Data Group, Inc. in the United States and/or other countries. 3537-4 FM.f.qc 12/15/00 15:31 Page v Welcome to the world of IDG Books Worldwide. IDG Books Worldwide, Inc., is a subsidiary of International Data Group, the world’s largest publisher of computer-related information and the leading global provider of information services on information technology. IDG was founded more than 30 years ago by Patrick J. McGovern and now employs more than 9,000 people worldwide. IDG publishes more than 290 computer publications in over 75 countries. More than 90 million people read one or more IDG publications each month. Launched in 1990, IDG Books Worldwide is today the #1 publisher of best-selling computer books in the United States. We are proud to have received eight awards from the Computer Press Association in recognition of editorial excellence and three from Computer Currents’ First Annual Readers’ Choice Awards. Our best- selling ...For Dummies® series has more than 50 million copies in print with translations in 31 languages. IDG Books Worldwide, through a joint venture with IDG’s Hi-Tech Beijing, became the first U.S. publisher to publish a computer book in the People’s Republic of China. In record time, IDG Books Worldwide has become the first choice for millions of readers around the world who want to learn how to better manage their businesses. Our mission is simple: Every one of our books is designed to bring extra value and skill-building instructions to the reader. Our books are written by experts who understand and care about our readers. The knowledge base of our editorial staff comes from years of experience in publishing, education, and journalism — experience we use to produce books to carry us into the new millennium. In short, we care about books, so we attract the best people. 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Founded in 1964, IDG had 1997 revenues of $2.05 billion and has more than 9,000 employees worldwide. IDG offers the widest range of media options that reach IT buyers in 75 countries representing 95% of worldwide IT spending. IDG’s diverse product and services portfolio spans six key areas including print publishing, online publishing, expositions and conferences, market research, education and training, and global marketing services. More than 90 million people read one or more of IDG’s 290 magazines and newspapers, including IDG’s leading global brands — Computerworld, PC World, Network World, Macworld and the Channel World family of publications. IDG Books Worldwide is one of the fastest-growing computer book publishers in the world, with more than 700 titles in 36 languages. The “...For Dummies®” series alone has more than 50 million copies in print. 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IDG Marketing Services helps industry-leading IT companies build international brand recognition by developing global integrated marketing programs via IDG’s print, online and exposition products worldwide. Further information about the company can be found at www.idg.com. 1/26/00 3537-4 FM.f.qc 12/15/00 15:31 Page vi Credits QUALITY CONTROL TECHNICIAN ACQUISITIONS EDITOR Dina F Quan Debra Williams Cauley PERMISSIONS EDITOR PROJECT EDITOR Laura Moss Neil Romanosky MEDIA DEVELOPMENT SPECIALIST TECHNICAL EDITORS Angela Denny Richard Lynch Michael Widenius MEDIA DEVELOPMENT COORDINATOR Marisa Pearman COPY EDITOR S. B. Kleinman BOOK DESIGNER Jim Donohue PROJECT COORDINATORS Louigene A. Santos ILLUSTRATORS Danette Nurse Gabriele McCann Ronald Terry GRAPHICS AND PRODUCTION SPECIALISTS PROOFREADING AND INDEXING Robert Bilhmayer York Production Services Rolly Delrosario Jude Levinson COVER IMAGE Michael Lewis ©Noma/Images.com Ramses Ramirez Victor Pérez-Varela About the Authors Jay Greenspan made his living as a technical consultant and editor before finding his way into Wired Digital’s Webmonkey. There he learned everything he knows about Web technology and gained an appreciation for electronic music, the color orange, and a “cute top.” He now makes his living as a writer and consultant. He will neither confirm nor deny the rumors that he once worked for a prime-time game show. Brad Bulgercan remember when computers were as big as refrigerators and old- timers would come into the machine room and call them “mini.” He learned more than anyone really should about database systems by working for Relational Technology nee Ingres nee CA for many years. After an interregnum, he got a job with Wired. He would still like to know when the future is going to get here, but has a sneaking suspicion he already knows. 3537-4 FM.f.qc 12/15/00 15:31 Page vii In memory of Dr. Jonathan B. Postel 3537-4 FM.f.qc 12/15/00 15:31 Page ix Preface Welcome. If you are thumbing through these pages, you’re probably considering writing Web-based applications with PHP and MySQL. If you decide to go with these tools, you’ll be in excellent company. Thousands of developers—from total newbies to programmers with years of experience—are turning to PHP and MySQL for their Web-based projects; and for good reason. Both PHP and MySQL are easy to use, fast, free, and powerful. If you want to get a dynamic Web site up quickly, there are no better choices. The PHP scripting lan- guage was built for the Web. All the tasks common to Web development can be accomplished in PHP with an absolute minimum of effort. Similarly, MySQL excels at tasks common to dynamic Web sites. Whether you’re creating a content-management system or an e-commerce application, MySQL is a great choice for your data storage. Is This Book for You? There are quite a few books that deal with PHP and a few that cover MySQL. We’ve read some of these and found a few to be quite helpful. If you’re looking for a book that deals with gory details of either of these packages, you should probably look elsewhere. The focus of this book is applications development. We are concerned with what it takes to get data-driven Web sites up and running in an organized and efficient way. The book does not go into arcane detail of every aspect of either of these tools. For example, in this book, you will not find a discussion of PHP’s LDAP functions or MySQL’s C application program interface (API). Instead, we will focus on the pieces of both packages that affect one another. We hope that by the time you’re done with this book you’ll know what it takes to get an application up and running using PHP and MySQL. How This Book Is Organized We have organized the book into four parts. Part I: Using MySQL Before you code any PHP scripts, you will need to know how to design a database, create tables in your database, and get the information you want from the database. Part I of this book will show you about all you need to know to work with MySQL. ix 3537-4 FM.f.qc 12/15/00 15:31 Page x x Preface Part II: Using PHP As an applications developer, the bulk of your time will be spent writing scripts that access the database and present HTML to a user’s browser. Part II will start by showing you the basics of the PHP scripting language, covering how PHP works with variables, conditions, and control structures. Part II will also cover many of PHP’s functions and discuss techniques for writing clean, manageable code. Part III: Simple Applications In this part, we present two of the seven applications in this book: a guestbook and a survey. Here you will see the lessons from Parts I and II put into practice as we build working applications. Part IV: Not So Simple Applications Here the applications will be more complex, as we present applications commonly used on the Web. You will see how you can design a content management system, a discussion board, a shopping cart, and other useful applications. Along the way, we will show some tips and techniques that should be helpful as you write your applications. Part V: Appendixes The appendixes cover several topics of interest to the MySQL/PHP developer. In the appendixes, you will find installation and configuration instructions, quick refer- ence guides to PHP and MySQL functions, a regular expressions overview, and guides to MySQL administration. In addition, there are a few helpful resources, snippets of code, and instructions on using the CD-ROM. Tell Us What You Think Both the publisher and authors of this book hope you find it a valuable resource. Please feel free to register this book at the IDG Books Web site (http://www. idgbooks.com) and give us your feedback. Also check in at the site we’ve dedicated to this book, http://www.mysqlphpapps.com/, where you will be able to contact the authors and find updates to the applications created for this book. 3537-4 FM.f.qc 12/15/00 15:31 Page xi Acknowledgments This book would never have happened if not for the efforts of Debra Williams Cauley. I thank her for her patience and persistence. The efforts and talents of Neil Romanosky, S. B. Kleinman, and many others at IDG Books have made this book more lucid and attractive than we could have hoped. Richard Lynch’s exacting eye and technical acumen kept our code clean, fast, and readable. Any book on open-source software owes debt to those who have created these great tools. So I thank everyone involved with PHP and MySQL, from the core developers to those who contribute to the documentation. Special thanks to Michael (Monty) Widenius, MySQL’s lead developer. He has not only created a ter- rific relational database, but has offered his advice and expertise to the authors of this book. xi