PHP and MySQL Web Development

893 Pages·2001·7.059 MB·English

by  Luke Welling, Laura Thomson

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PHP and MySQL
Web Development
Luke Welling and Laura Thomson
201 West 103rd St.,Indianapolis,Indiana,46290 USA
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PHP and MySQL Web Development ACQUISITIONSEDITOR
Shelley Johnston Markanday
Copyright © 2001 by Sams Publishing
DEVELOPMENTEDITOR
All rights reserved. No part of this book shall be reproduced,stored in a
Scott D. Meyers
retrieval system,or transmitted by any means,electronic,mechanical,photo-
copying,recording,or otherwise,without written permission from the pub- MANAGINGEDITOR
lisher. No patent liability is assumed with respect to the use of the information Charlotte Clapp
contained herein. Although every precaution has been taken in the preparation
COPYEDITOR
of this book,the publisher and author assume no responsibility for errors or
Rhonda Tinch-Mize
omissions. Neither is any liability assumed for damages resulting from the use
of the information contained herein. INDEXER
Kelly Castell
International Standard Book Number:0-672-31784-2
Library of Congress Catalog Card Number:99-64841 PROOFREADERS
Kathy Bidwell
Printed in the United States of America
Tony Reitz
First Printing:March 2001
TECHNICALEDITORS
04 03 02 01 4 3 2 1 Israel Denis
Chris Newman
Trademarks
All terms mentioned in this book that are known to be trademarks or service TEAMCOORDINATOR
Amy Patton
marks have been appropriately capitalized. Sams Publishing cannot attest to
the accuracy of this information. Use of a term in this book should not be SOFTWAREDEVELOPMENT
regarded as affecting the validity of any trademark or service mark. SPECIALIST
Dan Scherf
Warning and Disclaimer
INTERIORDESIGN
Every effort has been made to make this book as complete and as accurate as Anne Jones
possible,but no warranty or fitness is implied. The information provided is on
COVERDESIGN
an “as is”basis. The authors and the publisher shall have neither liability nor
Anne Jones
responsibility to any person or entity with respect to any loss or damages aris-
ing from the information contained in this book or from the use of the CD- PRODUCTION
ROM or programs accompanying it. Ayanna Lacey
Heather Hiatt Miller
Stacey Richwine-DeRome
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Overview
Introduction 1
PART I Using PHP
1 PHP Crash Course 9
2 Storing and Retrieving Data 49
3 Using Arrays 69
4 String Manipulation and Regular Expressions 93
5 Reusing Code and Writing Functions 117
6 Object-Oriented PHP 147
PART II Using MySQL
7 Designing Your Web Database 171
8 Creating Your Web Database 183
9 Working with Your MySQL Database 207
10 Accessing Your MySQL Database from the Web with PHP 227
11 Advanced MySQL 245
PART III E-commerce and Security
12 Running an E-commerce Site 267
13 E-commerce Security Issues 281
14 Implementing Authentication with PHP and MySQL 303
15 Implementing Secure Transactions with PHP and MySQL 327
PART IV Advanced PHP Techniques
16 Interacting with the File System and the Server 351
17 Using Network and Protocol Functions 369
18 Managing the Date and Time 391
19 Generating Images 401
20 Using Session Control in PHP 429
21 Other Useful Features 447
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PART V Building Practical PHP and MySQL Projects
22 Using PHP and MySQL for Large Projects 459
23 Debugging 477
24 Building User Authentication and Personalization 497
25 Building a Shopping Cart 539
26 Building a Content Management System 587
27 Building a Web-Based Email Service 617
28 Building a Mailing List Manager 655
29 Building Web Forums 711
30 Generating Personalized Documents in Portable Document Format (PDF) 743
PART VI
A Installing PHP 4 and MySQL 781
B Web Resources 803
Index 807
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Contents
Introduction 1
Who Should Read This Book? ..............................................................1
What Is PHP? ..........................................................................................1
What Is MySQL? ....................................................................................2
Why Use PHP and MySQL? ..................................................................2
Some of PHP’s Strengths ........................................................................3
Performance ......................................................................................3
Database Integration ..........................................................................3
Built-In Libraries ..............................................................................4
Cost ....................................................................................................4
Learning PHP ....................................................................................4
Portability ..........................................................................................4
Source Code ......................................................................................4
Some of MySQL’s Strengths ..................................................................4
Performance ......................................................................................5
Low Cost ..........................................................................................5
Ease of Use ........................................................................................5
Portability ..........................................................................................5
Source Code ......................................................................................5
How Is This Book Organized? ..............................................................5
What’s New in PHP Version 4? ..............................................................6
Finally ....................................................................................................6
PART I Using PHP 7
1 PHP Crash Course 9
Using PHP ............................................................................................11
Sample Application:Bob’s Auto Parts ................................................11
The Order Form ..............................................................................11
Processing the Form ........................................................................13
Embedding PHP in HTML ..................................................................13
Using PHP Tags ..............................................................................14
PHP Tag Styles ................................................................................15
PHP Statements ..............................................................................15
Whitespace ......................................................................................16
Comments ........................................................................................16
Adding Dynamic Content ....................................................................17
Calling Functions ............................................................................18
The date() Function ........................................................................18
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Accessing Form Variables ....................................................................19
Form Variables ................................................................................19
String Concatenation ......................................................................20
Variables and Literals ......................................................................21
Identifiers ..............................................................................................21
User-Declared Variables ......................................................................22
Assigning Values to Variables ..............................................................22
Variable Types ......................................................................................22
PHP’s Data Types ............................................................................22
Type Strength ..................................................................................23
Type Casting ....................................................................................23
Variable Variables ............................................................................23
Constants ..............................................................................................24
Variable Scope ......................................................................................25
Operators ..............................................................................................25
Arithmetic Operators ......................................................................26
String Operators ..............................................................................27
Assignment Operators ....................................................................27
Comparison Operators ....................................................................29
Logical Operators ............................................................................30
Bitwise Operators ............................................................................31
Other Operators ..............................................................................32
Using Operators:Working Out the Form Totals ..................................33
Precedence and Associativity:Evaluating Expressions ........................34
Variable Functions ................................................................................36
Testing and Setting Variable Types ................................................36
Testing Variable Status ....................................................................37
Reinterpreting Variables ..................................................................37
Control Structures ................................................................................38
Making Decisions with Conditionals ..................................................38
if Statements ....................................................................................38
Code Blocks ....................................................................................38
A Side Note:Indenting Your Code ................................................39
else Statements ................................................................................39
elseif Statements ..............................................................................40
switch Statements ............................................................................41
Comparing the Different Conditionals ............................................42
Iteration:Repeating Actions ................................................................43
while Loops ....................................................................................44
for Loops ........................................................................................45
do..while Loops ..............................................................................46
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CONTENTS
Breaking Out of a Control Structure or Script ....................................47
Next:Saving the Customer’s Order ......................................................47
2 Storing and Retrieving Data 49
Saving Data for Later ..........................................................................50
Storing and Retrieving Bob’s Orders ..................................................50
Overview of File Processing ................................................................52
Opening a File ......................................................................................52
File Modes ......................................................................................52
Using fopen() to Open a File ..........................................................53
Opening Files for FTP or HTTP ....................................................54
Problems Opening Files ..................................................................55
Writing to a File ....................................................................................57
Parameters for fwrite() ....................................................................57
File Formats ....................................................................................58
Closing a File ........................................................................................58
Reading from a File ..............................................................................59
Opening a File for Reading:fopen() ..............................................60
Knowing When to Stop:feof() ........................................................60
Reading a Line at a Time:fgets(),fgetss(),and fgetcsv() ..............60
Reading the Whole File:readfile(),fpassthru(),file() ....................61
Reading a Character:fgetc() ..........................................................62
Reading an Arbitrary Length:fread() ..............................................63
Other Useful File Functions ................................................................63
Checking Whether a File Is There:file_exists() ............................63
Knowing How Big a File Is:filesize() ............................................63
Deleting a File:unlink() ..................................................................63
Navigating Inside a File:rewind(),fseek(),and ftell() ..................64
File Locking ..........................................................................................65
Doing It a Better Way:Database Management Systems ......................66
Problems with Using Flat Files ......................................................66
How RDBMSs Solve These Problems ............................................67
Further Reading ....................................................................................67
Next ......................................................................................................67
3 Using Arrays 69
What Is an Array? ................................................................................70
Numerically Indexed Arrays ................................................................71
Initializing Numerically Indexed Arrays ........................................71
Accessing Array Contents ..............................................................72
Using Loops to Access the Array ....................................................73
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Associative Arrays ................................................................................73
Initializing an Associative Array ....................................................73
Accessing the Array Elements ........................................................73
Using Loops with each() and list() ..................................................74
Multidimensional Arrays ......................................................................75
Sorting Arrays ......................................................................................79
Using sort() ......................................................................................79
Using asort() and ksort() to Sort Associative Arrays ......................79
Sorting in Reverse ..........................................................................80
Sorting Multidimensional Arrays ........................................................80
User Defined Sorts ..........................................................................80
Reverse User Sorts ..........................................................................82
Reordering Arrays ................................................................................83
Using shuffle() ................................................................................83
Using array_reverse() ......................................................................84
Loading Arrays from Files ....................................................................85
Other Array Manipulations ..................................................................88
Navigating Within an Array:each,current(),reset(),
end(),next(),pos(),and prev() ....................................................88
Applying Any Function to Each Element in an Array:
array_walk() ..................................................................................89
Counting Elements in an Array:count(),sizeof(),and
array_count_values() ....................................................................90
Converting Arrays to Scalar Variables:extract() ............................91
Further Reading ....................................................................................92
Next ......................................................................................................92
4 String Manipulation and Regular Expressions 93
Example Application:Smart Form Mail ..............................................94
Formatting Strings ................................................................................96
Trimming Strings:chop(),ltrim(),and trim() ................................96
Formatting Strings for Presentation ................................................97
Formatting Strings for Storage:AddSlashes() and StripSlashes() 100
Joining and Splitting Strings with String Functions ..........................101
Using explode(),implode(),and join() ........................................102
Using strtok() ................................................................................102
Using substr() ................................................................................103
Comparing Strings ..............................................................................104
String Ordering:strcmp(),strcasecmp(),and strnatcmp() ............104
Testing String Length with strlen() ..............................................105
Matching and Replacing Substrings with String Functions ..............105
Finding Strings in Strings:strstr(),strchr(),strrchr(),stristr() ......106
Finding the Position of a Substring:strpos(),strrpos() ................107
Replacing Substrings:str_replace(),substr_replace() ..................108
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CONTENTS
Introduction to Regular Expressions ..................................................109
The Basics ....................................................................................109
Character Sets and Classes ............................................................110
Repetition ......................................................................................111
Subexpressions ..............................................................................111
Counted Subexpressions ................................................................112
Anchoring to the Beginning or End of a String ............................112
Branching ......................................................................................112
Matching Literal Special Characters ............................................112
Summary of Special Characters ....................................................113
Putting It All Together for the Smart Form ..................................113
Finding Substrings with Regular Expressions ....................................114
Replacing Substrings with Regular Expressions ................................115
Splitting Strings with Regular Expressions ........................................115
Comparison of String Functions and Regular Expression
Functions ..........................................................................................116
Further Reading ..................................................................................116
Next ....................................................................................................116
5 Reusing Code and Writing Functions 117
Why Reuse Code? ..............................................................................118
Cost ................................................................................................118
Reliability ......................................................................................119
Consistency ....................................................................................119
Using require() and include() ............................................................119
Using require() ..............................................................................119
File Name Extensions and Require() ............................................120
PHP Tags and require() ................................................................121
Using require() for Web Site Templates ............................................121
Using auto_prepend_file and auto_append_file ............................126
Using include() ..............................................................................127
Using Functions in PHP ....................................................................129
Calling Functions ..........................................................................129
Call to Undefined Function ..........................................................131
Case and Function Names ............................................................132
Why Should You Define Your Own Functions? ................................132
Basic Function Structure ....................................................................132
Naming Your Function ..................................................................133
Parameters ..........................................................................................134
Scope ..................................................................................................136
Pass by Reference Versus Pass by Value ............................................138
Returning from Functions ..................................................................140
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Returning Values from Functions ......................................................141
Code Blocks ..................................................................................142
Recursion ............................................................................................143
Further Reading ..................................................................................145
Next ....................................................................................................145
6 Object-Oriented PHP 147
Object-Oriented Concepts ..................................................................148
Classes and Objects ......................................................................148
Polymorphism ................................................................................149
Inheritance ....................................................................................150
Creating Classes,Attributes,Operations in PHP ..............................150
Structure of a Class ......................................................................151
Constructors ..................................................................................151
Instantiation ........................................................................................152
Using Class Attributes ........................................................................152
Calling Class Operations ....................................................................154
Implementing Inheritance in PHP ......................................................155
Overriding ......................................................................................156
Multiple Inheritance ......................................................................157
Designing Classes ..............................................................................158
Writing the Code for Your Class ........................................................159
Next ....................................................................................................168
PART II Using MySQL 169
7 Designing Your Web Database 171
Relational Database Concepts ............................................................172
Tables ............................................................................................173
Columns ........................................................................................173
Rows ..............................................................................................173
Values ............................................................................................173
Keys ..............................................................................................173
Schemas ........................................................................................175
Relationships ................................................................................175
How to Design Your Web Database ....................................................176
Think About the Real World Objects You Are Modeling ............176
Avoid Storing Redundant Data ....................................................176
Use Atomic Column Values ..........................................................178
Choose Sensible Keys ..................................................................179
Think About the Questions You Want to Ask the Database ..........179
Avoid Designs with Many Empty Attributes ................................179
Summary of Table Types ..............................................................180