Learning PHP, MySQL, and JavaScript Robin Nixon Beijing • Cambridge • Farnham • Köln • Sebastopol • Taipei • Tokyo Learning PHP, MySQL, and JavaScript by Robin Nixon Copyright © 2009 Robin Nixon. All rights reserved. Printed in the United States of America. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (http://my.safaribooksonline.com). For more information, contact our corporate/institutional sales department: (800) 998-9938 or [email protected]. Editor: Andy Oram Indexer: Ellen Troutman Zaig Production Editor: Sumita Mukherji Cover Designer: Karen Montgomery Copyeditor: Nancy Kotary Interior Designer: David Futato Proofreader: Kiel Van Horn Illustrator: Robert Romano Printing History: July 2009: First Edition. Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. Learning PHP, MySQL, and JavaScript, the image of sugar gliders, and related trade dress are trademarks of O’Reilly Media, Inc. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and O’Reilly Media, Inc., was aware of a trademark claim, the designations have been printed in caps or initial caps. While every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions, or for damages resulting from the use of the information con- tained herein. TM This book uses RepKover™, a durable and flexible lay-flat binding. ISBN: 978-0-596-15713-5 [M] 1246467361 Table of Contents Preface . xiii 1. Introduction to Dynamic Web Content ... ................................... 1 HTTP and HTML: Berners-Lee’s Basics 2 The Request/Response Procedure 2 The Benefits of PHP, MySQL, and JavaScript 5 Using PHP 5 Using MySQL 6 Using JavaScript 7 The Apache Web Server 8 About Open Source 9 Bringing It All Together 9 Test Your Knowledge: Questions 11 2. Setting Up a Development Server . ...................................... 13 What Is a WAMP, MAMP, or LAMP? 13 Installing a WAMP on Windows 14 Overcoming Installation Problems 14 Testing the Installation 16 Alternative WAMPs 18 Installing a MAMP on Mac OS X 19 Some Final Tweaking 24 Other Alternatives 25 Installing a LAMP on Linux 25 Working Remotely 26 Logging In 27 Using FTP 27 Using a Program Editor 28 Using an IDE 30 Test Your Knowledge: Questions 32 iii 3. Introduction to PHP . ................................................. 33 Incorporating PHP Within HTML 33 Calling the PHP Parser 34 This Book’s Examples 35 The Structure of PHP 36 Using Comments 36 Basic Syntax 37 Understanding Variables 38 Operators 42 Variable Assignment 45 Multiple-Line Commands 47 Variable Typing 49 Constants 50 The Difference Between the echo and print Commands 51 Functions 52 Variable Scope 53 Test Your Knowledge: Questions 58 4. Expressions and Control Flow in PHP . ................................... 61 Expressions 61 Literals and Variables 62 Operators 63 Operator Precedence 64 Associativity 66 Relational Operators 67 Conditionals 70 The if Statement 71 The else Statement 72 The elseif Statement 73 The switch Statement 74 The ? Operator 77 Looping 78 while Loops 78 do...while Loops 80 for Loops 81 Breaking Out of a Loop 83 The continue Statement 84 Implicit and Explicit Casting 84 PHP Dynamic Linking 85 Dynamic Linking in Action 86 Test Your Knowledge: Questions 87 iv | Table of Contents 5. PHP Functions and Objects . ........................................... 89 PHP Functions 90 Defining a Function 91 Returning a Value 92 Returning an Array 93 Passing by Reference 94 Returning Global Variables 95 Recap of Variable Scope 96 Including and Requiring Files 96 The include Statement 96 Using include_once 97 Using require and require_once 97 PHP Version Compatibility 98 PHP Objects 98 Terminology 99 Declaring a Class 100 Creating an Object 101 Accessing Objects 101 Constructors 104 Writing Methods 105 Declaring Properties 106 Declaring Constants 107 Property and Method Scope in PHP 5 107 Inheritance 109 Test Your Knowledge: Questions 113 6. PHP Arrays . 115 Basic Access 115 Numerically Indexed Arrays 115 Associative Arrays 117 Assignment Using the array Keyword 118 The foreach...as Loop 119 Multidimensional Arrays 121 Using Array Functions 123 is_array() 123 count() 124 sort() 124 shuffle() 124 explode() 125 extract() 125 compact() 126 reset() 127 end() 128 Table of Contents | v Test Your Knowledge: Questions 128 7. Practical PHP . ...................................................... 129 Using printf 129 Precision Setting 131 String Padding 132 Using sprintf 133 Date and Time Functions 133 Date Constants 136 Using checkdate 136 File Handling 137 Checking Whether a File Exists 137 Creating a File 137 Reading from Files 139 Copying Files 139 Moving a File 140 Deleting a File 140 Updating Files 141 Locking Files for Multiple Accesses 142 Reading an Entire File 143 Uploading Files 144 System Calls 149 XHTML 151 The Benefits of XHTML 151 XHTML Versions 151 What’s Different? 152 HTML 4.01 Document Types 153 XHTML 1.0 Document Types 153 XHTML Validation 154 Test Your Knowledge: Questions 155 8. Introduction to MySQL . .............................................. 157 MySQL Basics 157 Summary of Database Terms 158 Accessing MySQL via the Command Line 158 Starting the Command-Line Interface 159 Using the Command-Line Interface 163 MySQL Commands 164 Data Types 168 Indexes 177 Creating an Index 178 Querying a MySQL Database 183 Joining Tables Together 192 vi | Table of Contents Using Logical Operators 194 MySQL Functions 194 Accessing MySQL via phpMyAdmin 195 Windows Users 195 Mac OS X Users 195 Linux Users 195 Using phpMyAdmin 197 Test Your Knowledge: Questions 198 9. Mastering MySQL ... .................................................. 201 Database Design 201 Primary Keys: The Keys to Relational Databases 202 Normalization 203 First Normal Form 204 Second Normal Form 206 Third Normal Form 208 When Not to Use Normalization 210 Relationships 211 One-to-One 211 One-to-Many 212 Many-to-Many 212 Databases and Anonymity 214 Transactions 214 Transaction Storage Engines 215 Using BEGIN 216 Using COMMIT 216 Using ROLLBACK 216 Using EXPLAIN 217 Backing Up and Restoring 218 Using mysqldump 219 Creating a Backup File 220 Restoring from a Backup File 222 Dumping Data in CSV Format 222 Planning Your Backups 223 Test Your Knowledge: Questions 223 10. Accessing MySQL Using PHP . ......................................... 225 Querying a MySQL Database with PHP 225 The Process 225 Creating a Login File 226 Connecting to MySQL 227 A Practical Example 232 The $_POST Array 234 Table of Contents | vii Deleting a Record 235 Displaying the Form 236 Querying the Database 236 Running the Program 237 Practical MySQL 238 Creating a Table 238 Describing a Table 239 Dropping a Table 240 Adding Data 240 Retrieving Data 241 Updating Data 242 Deleting Data 242 Using AUTO_INCREMENT 243 Performing Additional Queries 244 Preventing SQL Injection 245 Preventing HTML Injection 248 Test Your Knowledge: Questions 250 11. Form Handling .. .................................................... 251 Building Forms 251 Retrieving Submitted Data 253 register_globals: An Old Solution Hangs On 254 Default Values 254 Input Types 256 Text Boxes 256 Text Areas 256 Checkboxes 257 Radio Buttons 259 Hidden Fields 260 Select 260 Labels 262 Sanitizing Input 262 An Example Program 264 Test Your Knowledge: Questions 266 12. Templating with Smarty . ............................................ 269 Why Smarty? 270 Installation 270 Creating Scripts 271 Creating Templates 272 A Practical Example 272 Test Your Knowledge: Questions 277 viii | Table of Contents 13. Cookies, Sessions, and Authentication . 279 Using Cookies in PHP 279 Setting a Cookie 281 Accessing a Cookie 281 Destroying a Cookie 282 HTTP Authentication 282 Storing Usernames and Passwords 285 Salting 285 Using Sessions 289 Starting a Session 289 Ending a Session 292 Session Security 293 Test Your Knowledge: Questions 296 14. Exploring JavaScript . ................................................ 299 JavaScript and HTML Text 299 Using Scripts Within a Document Head 301 Older and Nonstandard Browsers 301 Including JavaScript Files 302 Debugging JavaScript Errors 303 Using Comments 305 Semicolons 305 Variables 306 String Variables 306 Numeric Variables 307 Arrays 307 Operators 308 Arithmetic Operators 308 Assignment Operators 308 Comparison Operators 309 Logical Operators 309 Variable Incrementing and Decrementing 310 String Concatenation 310 Escaping Characters 310 Variable Typing 311 Functions 312 Global Variables 312 Local Variables 312 The Document Object Model 314 Browser Incompatibilities 316 Using the DOM 317 Test Your Knowledge: Questions 318 Table of Contents | ix 15. Expressions and Control Flow in JavaScript . 319 Expressions 319 Literals and Variables 320 Operators 321 Operator Precedence 321 Associativity 322 Relational Operators 323 The with Statement 325 Using onError 326 Using try...catch 327 Conditionals 328 The if Statement 328 The switch Statement 329 The ? Operator 331 Looping 331 while Loops 331 do...while Loops 332 for Loops 332 Breaking Out of a Loop 333 The continue Statement 334 Explicit Casting 334 Test Your Knowledge: Questions 335 16. JavaScript Functions, Objects, and Arrays . 337 JavaScript Functions 337 Defining