PHP & MySQL® Everyday Apps for dummies ppt

by Janet Valade
PHP & MySQL
®
Everyday Apps
FOR
DUMmIES
‰
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PHP & MySQL
®
Everyday Apps
FOR
DUMmIES
‰
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by Janet Valade
PHP & MySQL
®
Everyday Apps
FOR
DUMmIES
‰
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PHP & MySQL
®
Everyday Apps For Dummies
®
Published by

Wiley Publishing, Inc.
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Hoboken, NJ 07030-5774
www.wiley.com
Copyright © 2005 by Wiley Publishing, Inc., Indianapolis, Indiana
Published by Wiley Publishing, Inc., Indianapolis, Indiana
Published simultaneously in Canada
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About the Author
Janet Valade has 20 years of experience in the computing field. Her back-
ground includes work as a technical writer for several companies, as a Web
designer/programmer for an engineering firm, and as a systems analyst in a
university environment where, for over ten years, she supervised the installa-
tion and operation of computing resources, designed and developed a state-
wide data archive, provided technical support to faculty and staff, wrote
numerous technical papers and documentation, and designed and presented
seminars and workshops on a variety of technology topics.
Janet currently has two published books: PHP & MySQL For Dummies, 2nd
Edition, and PHP 5 For Dummies. In addition, she has authored chapters for
several Linux and Web development books.
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Dedication
This book is dedicated to anyone who finds it useful.
Author’s Acknowledgments
I wish to express my appreciation to the entire Open Source community.
Without those people who give their time and talent, there would be no cool
PHP for me to write about. Furthermore, I never would have learned this soft-
ware without the PHP lists where people generously spend their time answer-
ing foolish questions from beginners. Many ideas have come from reading
questions and answers on the lists.
I want to thank my mother for passing on a writing gene and a good work
ethic. Anything I accomplish has its roots in my beginnings. And, of course,
thank you to my children who manage to remain close, though far away, and
nourish my spirit.
And, of course, I want to thank the professionals who made it all possible.
Without my agent, my editors, and all the other people at Wiley, this book
would not exist. Because they all do their jobs so well, I can contribute my
part to this joint project.
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Publisher’s Acknowledgments
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Contents at a Glance
Introduction 1
Part I: Introducing Application Development 7
Chapter 1: Building Your Application 9
Chapter 2: Building in Application Security 23
Part II: Building a User Authentication Application 43
Chapter 3: User Authentication with HTTP 45
Chapter 4: User Login Application 77
Part III: Building Online Sales Applications 129
Chapter 5: Online Catalog Application 131
Chapter 6: Shopping Cart Application 159
Part IV: Building Other Useful Applications 233
Chapter 7: Building a Content Management System 235
Chapter 8: Hosting Discussions with a Web Forum 309
Part V: The Part of Tens 373
Chapter 9: Ten Hints for Application Development 375
Chapter 10: Ten Sources of PHP Code 379
Part VI: Appendixes 383
Appendix A: Introducing Object-Oriented Programming 385
Appendix B: Object-Oriented Programming with PHP 391
Appendix C: The MySQL and MySQL Improved Extensions 407
Appendix D: About the CD 411
Index 417
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Table of Contents
Introduction 1

About This Book 1
Conventions Used in This Book 1
Foolish Assumptions 2
How This Book Is Organized 3
Part I: Introducing Application Development 3
Part II: Building a User Authentication Application 4
Part III: Building Online Sales Applications 4
Part IV: Building Other Useful Applications 4
Part V: The Part of Tens 4
Part VI: Appendixes 4
About the CD 5
Icons Used in This Book 5
Where to Go from Here 5
Part I: Introducing Application Development 7
Chapter 1: Building Your Application . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Understanding PHP and MySQL Versions 10
MySQL 11
PHP 11
PHP and MySQL together 12
Using the Application Source Code 13
Choosing a location 13
Understanding the PHP code 14
Procedural versus object-oriented programs 15
Modifying the Source Code 16
Programming editors 17
Integrated Development Environment (IDE) 18
Planning Your Application 19
Planning the software 20
Additional planning 20
Chapter 2: Building in Application Security . . . . . . . . . . . . . . . . . . . . .23

Understanding Security Risks 24
Building Security into Your PHP Scripts 24
Don’t trust any information from an outside source 25
Storing information 30
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Using system calls 31
Handling errors 32
MySQL Security 33
Setting up accounts and passwords 33
Accessing MySQL from PHP scripts 37
Understanding SQL injection attacks 38
Backing up your databases 40
Using a Secure Web Server 41
Part II: Building a User Authentication Application 43
Chapter 3: User Authentication with HTTP . . . . . . . . . . . . . . . . . . . . . .45
Understanding HTTP Authentication 46
Understanding how the WWW works 46
Requesting a password-protected file 47
Authorizing access 48
Using HTTP Authentication with Apache 49
Configuring Apache 49
Creating the .htaccess file 50
Creating the password file 51
Apache HTTP authentication in action 52
Designing an HTTP Authentication Application in PHP 52
Creating a User Database 54
Designing the user database 54
Creating the user database 55
Accessing the user database 55
Building the Authentication Application in PHP:

The Procedural Approach 56
Building the Authentication Application in PHP:
The Object-Oriented Approach 60
Developing the objects 60
Writing the PasswordPrompter class 61
Writing the Database class 62
Writing the Account class 66
Writing the WebPage class 71
Writing the Auth-OO script 73
Chapter 4: User Login Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Designing the Login Application 78
Creating the User Database 78
Designing the database 79
Building the database 80
Accessing the database 81
Adding data to the database 81
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Building the Login Web Page 82
Designing the login Web page 82
Writing the code for the login page 83
Displaying the login Web page 91
Building the Login Application: The Procedural Approach 91
Writing the application script 92
Protecting your Web pages 100
Building the Login Application: The Object-Oriented Approach 101
Developing the objects 101
Writing the WebForm class 102
Writing the Database class 110

Writing the Account class 111
Writing the Session class 114
Writing the Email class 117
Writing the login application script 119
Protecting your Web pages 126
Adding Features to the Application 126
Part III: Building Online Sales Applications 129
Chapter 5: Online Catalog Application . . . . . . . . . . . . . . . . . . . . . . . . .131
Designing the Online Catalog Application 131
Creating the Catalog Database 132
Designing the Catalog database 132
Building the Catalog database 134
Accessing the food database 134
Adding data to the database 135
Building the Catalog Web Pages 135
Designing the catalog Web pages 136
Writing the code for the index page 138
Writing the code for the products page 140
Displaying the catalog Web pages 145
Building the Online Catalog Application: Procedural Approach 145
Building the Online Catalog Application: The Object-Oriented
Approach 149
Developing the Objects 149
Writing the Catalog class 150
Writing the catalog application script 155
Growing the Catalog class 157
Chapter 6: Shopping Cart Application . . . . . . . . . . . . . . . . . . . . . . . . .159
Designing the Shopping Cart Application 159
Basic application design decisions 159
Application functionality design 161

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Creating the Shopping Cart Database 162
Designing the shopping cart database 162
Building the shopping cart database 164
Accessing the shopping cart database 165
Adding data to the shopping cart database 165
Building the Shopping Cart Web Pages 166
Designing the shopping cart Web pages 166
Writing the code for the product information page 171
Writing the code for the shopping cart Web page 175
Writing the code for the shipping information form 182
Writing the code for the summary page 187
Building the Shopping Cart Application: The Procedural Approach 193
Writing ShopCatalog.php 193
Writing ShoppingCart.php 197
Writing ProcessOrder.php 200
Building the Shopping Cart Application:
The Object-Oriented Approach 207
Developing the objects 207
Writing the Catalog class 208
Writing the Item class 210
Writing the ShoppingCart class 212
Writing the Database class 215
Writing the Order class 216
Writing the WebForm class 221
Writing the WebPage class 222
Writing the Email Class 223
Writing the shopping cart application script 223

Adding Features to the Application 231
Part IV: Building Other Useful Applications 233
Chapter 7: Building a Content Management System . . . . . . . . . . . . .235
Designing the CMS Application 235
Creating the CMS Database 236
Designing the CMS database 237
Building the CMS database 240
Accessing the CMS database 243
Designing the CMS Web Pages 243
Building the CMS Application: Procedural Approach 246
Writing the login code 246
Writing CompanyHome.php, a data retrieval file 253
Writing company.inc, the main HTML display file 262
Writing the content detail code 265
Writing Admin.php, the data manipulation code 269
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Building the CMS Application: Object-Oriented Approach 275
Writing the object model 275
Writing a basic data class 277
Writing the Department class 279
Writing the ContentType class 281
Writing the ContentItem class 283
Writing the ContentDownload class 289
Writing the Database class 291
Writing the WebForm class 292
Writing the code for the login page 293
Writing fields_content.inc and content_form.inc 294
Writing the display code 294

Writing Admin-OO.php, the data manipulation code 303
Enhancing the Content Management System 307
Chapter 8: Hosting Discussions with a Web Forum . . . . . . . . . . . . . .309
Designing the Forum Application 309
Creating the Forum Database 310
Designing the Forum database 311
Building the forum tables 314
Accessing the forum tables 315
Adding data to the database 316
Building the Forum Web Pages 317
Designing the Forum Web pages 317
Writing the code for the Forums page 321
Writing the code for the Threads page 324
Writing the code for the Messages page 328
Writing the code for the New Message page 331
Writing the code for the Reply page 334
Building the Forum Application: Procedural Approach 337
Writing viewForums.php 337
Writing viewTopic.php 338
Writing viewThread.php 338
Writing postMessage.php 339
Writing postReply.php 342
Writing the supporting functions 345
Building the Forum Application: The Object-Oriented Approach 347
Developing the objects 348
Writing the TableAccessor class 349
Writing the Thread class 353
Writing the Post class 355
Writing the Database class 357
Writing the WebForm class 358

Writing the Forum application scripts 359
Writing the supporting functions 368
Possible Enhancements 371
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Part V: The Part of Tens 373
Chapter 9: Ten Hints for Application Development . . . . . . . . . . . . . .375
Plan First 375
Be Consistent 376
Test Code Incrementally 376
Remember Those Who Follow 376
Use Constants 376
Write Reusable Code 377
Separate Page Layout from Function 377
Don’t Reinvent the Wheel 377
Use the Discussion Lists Frequently, but Wisely 378
Document Everything 378
Chapter 10: Ten Sources of PHP Code . . . . . . . . . . . . . . . . . . . . . . . . .379
SourceForge.net 379
WeberDev 380
PHP Classes 380
Codewalkers 380
PHP Builder 381
HotScripts.com 381
Zend 381
PHP Freaks 382
PX: The PHP Code Exchange 382
Free PHP and MySQL Hosting Directory 382
Part VI: Appendixes 383

Appendix A: Introducing Object-Oriented Programming . . . . . . . . .385
Understanding Object-Oriented Programming Concepts 385
Objects and classes 386
Properties 386
Methods 387
Abstraction 387
Inheritance 388
Information hiding 389
Creating and Using the Class 390
Appendix B: Object-Oriented Programming with PHP . . . . . . . . . . .391
Writing a Class Statement 391
The class statement 391
Naming the class 392
Adding the class code 392
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Setting properties 392
Adding methods 394
Accessing properties and methods 395
Writing the constructor 396
Putting it all together 397
Using inheritance in your class 398
Using a Class 399
Creating an object 399
Using methods 399
Accessing properties 400
Using Exceptions 400
Copying Objects 401
Destroying Objects 402

Using Abstract Classes 403
Using Interfaces 404
Testing an Object 405
Object-Oriented Concepts That PHP 5 Omits 405
Appendix C: The MySQL and MySQL Improved Extensions . . . . . . .407
Appendix D: About the CD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .411
System Requirements 411
Using the CD 412
What You Can Find on the CD 412
Source code files 412
Links to useful PHP and MySQL information 413
A bonus chapter 414
Troubleshooting 414
Index 417
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Introduction
B
ecause you’re looking at a book called PHP & MySQL Everyday Apps For
Dummies, I assume you want to build a Web application with the PHP
scripting language and a MySQL backend database. If you need to build a
dynamic Web application for a specific purpose, you’re in the right place.
You will find six popular applications in this book and one additional applica-
tion chapter on the CD. If the exact application you need isn’t here, you can
probably adapt one of the applications to suit your needs.
About This Book

This book is a practical introduction to dynamic Web applications. It provides
the code and information needed to build several of the most popular appli-
cations on the Web. The applications in this book allow you to
ߜ Restrict your Web site or part of your Web site to authorized users
ߜ Sell products on your Web site
ߜ Provide a place where users can communicate with each other online
ߜ Allow users to publish and edit their documents on a Web site
ߜ Manage mailing lists
You can use these applications as is, modify them for use on your Web site,
or build your own application by using techniques that I show you in these
applications.
Conventions Used in This Book
This book includes many listings of PHP code. Line numbers appear at the end
of some of the lines in the listings. I explain the code after the code listing.
The line numbers in the explanation refer to the specific line in the code.
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In MySQL queries in the code listings, the SQL commands and key words
appear in uppercase letters. The parameters specific to your application,
such as the database name and field names, use their specific names, usually
lowercase letters or, sometimes, lowercase letters with a beginning upper-
case letter. For example, look at the following SQL query:
SELECT name FROM Customer WHERE account_number=”$acc_no”
The all-uppercase words are SQL commands and keywords, which must be
spelled exactly as shown. The words with lowercase letters are the names of
items in your database, such as the table name and field names.
A continuation symbol (
Æ) appears at the end of some lines of code to indi-
cate when a line is too long to fit in its allotted space on the printed page.
Foolish Assumptions
I assume that:

ߜ You’re building your Web application in an environment that includes
access to PHP and MySQL. This might be your own computer or a Web
hosting company. This book doesn’t include instructions for installing
PHP or MySQL. I assume that your environment is already installed and
working.
ߜ You have some experience with PHP. You don’t need to be an expert
PHP coder. You don’t need advanced PHP skills. You only need a basic
understanding of how PHP works and its basic features, such as if state-
ments and
foreach loops.
When I explain the code in the listings, I don’t explain each line in detail.
I provide a general description of the tasks performed by the script and
tasks performed by specific loops. I provide a detailed explanation only
for parts of the script that are specialized or potentially confusing.
Even if you don’t have experience with PHP, if you have programming
experience in another language, such as Perl or C, you might be able to
understand and use the applications in this book. PHP is close to C syntax
and is designed to be easy to use. Its features are quite familiar to anyone
with programming experience.
ߜ You have a basic understanding of MySQL. I don’t explain how to create
MySQL databases. I don’t provide any description of SQL. I do provide
SQL queries that you can use to create each database, but assume that
you know how to use the SQL query.
2
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ߜ You know HTML and a little CSS. If you have experience with PHP, you
necessarily have experience with HTML. I also assume a slight acquain-
tance with CSS. The applications in this book display some Web pages,
such as the catalog or the login screen, so HTML and CSS are included in

the code listings. I keep the HTML as simple as possible so that it doesn’t
interfere with your understanding of the PHP. However, some HTML is
necessary. In general, I use in-line CSS code to format the HTML. I don’t
explain the HTML or CSS.
How This Book Is Organized
This book is divided into six parts, with two chapters in each part. Chapters 3
through 8 present applications. An additional bonus application chapter
is included on the CD. Each application chapter includes the following
information:
ߜ Discussion of issues
ߜ Structure of the database
ߜ Code listings
ߜ Explanation of the code
Each application chapter presents both procedural code and object-oriented
code for the application.
The additional chapters provide information that’s useful when building
applications (for example, I demystify security considerations).
Part I: Introducing Application
Development
Chapter 1 in this part provides the information needed to use the applications
in this book. It discusses PHP and MySQL versions, installing and modifying
applications, and procedural versus object-oriented programming. In Chapter 2,
you find out how to write secure code.
3
Introduction
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Part II: Building a User Authentication
Application
This part provides information and code to build a user login application.
I present two types of applications: user authentication using HTTP authenti-

cation (Chapter 3) and a user login application that allows users to register
their own accounts, as well as log in to a secure Web site (Chapter 4).
Part III: Building Online
Sales Applications
This part provides information and code for online sales applications. In
Chapter 5, you find out how to write code for an application that provides an
online catalog. Chapter 6 covers writing an application that allows customers
to buy products from the catalog.
Part IV: Building Other
Useful Applications
In Part IV, I present two other applications that you may find useful. In
Chapter 7, I describe how to build a content management system (CMS).
I describe how to build a Web forum in Chapter 8.
Part V: The Part of Tens
This part provides a useful list of important things to keep in mind when build-
ing an application (Chapter 9). I also provide a list of Web sites offering useful
resources, such as code libraries, tutorials, articles, and so on (Chapter 10).
Part VI: Appendixes
This part provides instructions for object-oriented programming. Appendix
A provides an introduction to the object-oriented programming features of
PHP for people who know PHP, but are unfamiliar with the concepts and termi-
nology of object-oriented programming. Appendix B describes the syntax of
PHP object-oriented features for those who are familiar with object-oriented
4
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