book

Learning PHP and MySQL

by Michele E. Davis, Jon A. Phillips

June 2006

Beginner

376 pages

8h 55m

English

O'Reilly Media, Inc.

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Preface
AudienceAssumptions This Book MakesOrganization of This BookSupporting BooksConventions Used in This BookUsing Code ExamplesSafari® EnabledHow to Contact UsAcknowledgments
1. Dynamic Content and the Web
1.1. PHP and MySQL’s Place in Web Development1.1.1. Advantages of Using PHP with MySQL1.1.2. The Value of Open Source1.2. The Components of a PHP Application1.2.1. Birth of PHP1.2.2. Birth of Apache1.2.3. Apache Versions1.2.4. Birth of MySQL1.2.5. Compatibility1.3. Integrating Many Sources of Information1.3.1. MySQL Database1.3.2. PHP Templates1.3.3. Cascading Style Sheets1.3.4. HTML Markup1.4. Requesting Data from a Web Page1.4.1. PHP Interpretation on the Server1.5. Chapter 1 Questions
2. Installation
2.1. Developing Locally2.1.1. Installing Apache2.1.2. Installing PHP2.1.3. Installing MySQL 4.12.2. Working Remotely2.3. Chapter 2 Questions
3. Exploring PHP
3.1. PHP and HTML Text3.1.1. Text Output3.1.1.1. Separating PHP from HTML3.2. Coding Building Blocks3.2.1. Variables3.2.1.1. Reading a variable’s value3.2.1.2. Variable types3.2.1.3. Variable scope3.2.1.3.1. Global variables3.2.1.3.2. Static variables3.2.1.3.3. Super global variables3.2.2. Strings3.2.2.1. Special characters in strings3.2.2.2. Comparing strings3.2.3. Concatenation3.2.3.1. Combining strings with other types3.2.4. Constants3.2.4.1. Predefined constants3.2.5. Doing Math3.2.5.1. Combined assignment3.2.5.2. Autoincrement and autodecrement3.2.5.3. Pre-increment and -decrement3.3. Chapter 3 Questions
4. PHP Decision Making
4.1. Expressions4.2. Operator Concepts4.2.1. Number of Operands4.2.2. Types of Operands4.2.2.1. Order of precedence4.2.2.2. Associativity4.2.3. Relational Operators4.2.3.1. Equality4.2.3.2. Comparison operators4.2.3.3. Logical operators4.3. Conditionals4.3.1. The if Statement4.3.1.1. The else statement4.3.1.2. The elseif statement4.3.2. The ? Operator4.3.3. The switch Statement4.3.3.1. Breaking out4.3.3.2. Defaulting4.4. Looping4.4.1. while Loops4.4.2. do . . . while Loops4.4.3. for Loops4.4.4. Breaking Out of a Loop4.4.5. continue Statements4.5. Chapter 4 Questions
5. Functions
5.1. Calling Functions5.2. Defining Functions5.2.1. Parameters5.2.2. Parameter References5.2.3. Including and Requiring PHP Files5.2.4. The include Statement5.2.4.1. The include_once statement5.2.4.2. require and require_once functions5.2.5. Testing a Function5.3. Object-Oriented Programming5.3.1. Creating a Class5.3.2. Creating an Instance5.3.3. Methods and Constructors5.3.4. Variable Scope Within Classes5.3.5. Inheritance5.3.5.1. The extends operator5.3.5.2. The parent operator5.3.6. Static Methods and Variables5.3.6.1. The :: operator (scope resolution)5.3.7. Variable References5.4. Chapter 5 Questions
6. Arrays
6.1. Array Fundamentals6.1.1. Associative Versus Numeric Indexed Arrays6.1.2. Creating an Array6.1.2.1. Assignment via array identifiers6.1.2.2. Assignment using array6.1.2.3. Looping through and referencing array values6.1.2.4. Adding values to an array6.1.2.5. Counting how many elements are in an array6.1.2.6. Sorting arrays6.1.3. Multidimensional Arrays6.1.4. Extracting Variables from an Array6.1.4.1. Using compact to build an array from variables6.1.5. Array Functions in PHP6.2. Chapter 6 Questions
7. Database Basics
7.1. Database Design7.1.1. Relational Databases7.1.2. Relationship Types7.1.2.1. One-to-one relationships7.1.2.2. One-to-many relationships7.1.2.3. Many-to-many relationships7.1.3. Normalization7.1.4. Forms of Normalization7.1.4.1. First Normal Form7.1.4.2. Second Normal Form7.1.4.3. Third Normal Form7.1.5. Column Data Types7.2. Structured Query Language7.2.1. Creating Tables7.2.2. Adding Data to a Table7.2.3. Querying the Database7.2.3.1. Limit results with WHERE7.2.3.2. Specifying the order7.2.3.3. Joining tables together7.2.3.4. Natural joins7.2.3.5. Aliases7.2.4. Modifying Database Data7.2.5. Deleting Database Data7.2.6. Search Functions7.2.7. Logical Operators7.3. Chapter 7 Questions
8. Using MySQL
8.1. MySQL Database8.1.1. Accessing the Database with the Command Line8.1.1.1. Prompts8.1.1.2. Commands8.2. Managing the Database8.2.1. Creating Users8.2.2. Creating a MySQL Database8.2.3. Table Manipulation8.2.3.1. Renaming a table8.2.3.2. Changing a column’s data type8.2.3.3. Adding a column8.2.3.4. Remove a column8.2.3.5. Deleting an entire table8.2.4. Using phpMyAdmin8.3. Backing Up and Restoring Data8.3.1. Copying Database Files8.3.2. The mysqldump Command8.3.2.1. Backing up8.3.2.2. Restoring a MySQL backup8.3.2.3. Working with other formats8.3.2.4. The mysqlimport command8.3.2.5. Backup best practices8.4. Advanced SQL8.4.1. Indexes8.4.1.1. When indexes are used8.4.1.2. Where to specify the index8.4.1.3. Multicolumn indexes8.4.2. Selecting Using the LEFT JOIN ON Clause8.4.3. Using Database Functions8.4.3.1. String functions8.4.3.1.1. Concatenation8.4.3.1.2. Concatenation with a predefined separator8.4.3.1.3. Calculate a string length8.4.3.1.4. Changing strings to upper- or lowercase8.4.3.1.5. Trimming and padding strings8.4.3.1.6. String location and position8.4.3.1.7. Cutting up strings8.4.3.1.8. Search and replace function8.4.3.2. Date and time functions8.4.3.2.1. Days, months, years, and weeks8.4.3.2.2. Hours, minutes, and seconds8.4.3.2.3. Dates and times arithmetic8.4.3.2.4. NOW function8.4.3.2.5. Formatting for display8.5. Chapter 8 Questions
9. Getting PHP to Talk to MySQL
9.1. The Process9.1.1. Resources9.2. Querying the Database with PHP Functions9.2.1. Including Database Login Details9.2.2. Connecting to the Database9.2.2.1. Troubleshooting connection errors9.2.3. Selecting the Database9.2.4. Building the SQL SELECT Query9.2.5. Executing the Query9.2.6. Fetching and Displaying9.2.6.1. Fetch types9.2.7. Closing the Connection9.2.8. Putting It All Together9.3. Using PEAR9.3.1. Installing9.3.1.1. Unix9.3.1.2. Windows9.3.1.3. Hosted ISP9.3.2. Adding Additional Packages9.3.3. Rewriting the Books Example with PEAR9.3.3.1. Creating a connect instance9.3.3.2. Connect string9.3.3.3. Querying9.3.3.4. Fetching9.3.3.5. Closing9.3.3.6. PEAR error reporting9.4. Chapter 9 Questions

10. Working with Forms
10.1. Building a Form10.1.1. Accessing Submitted Form Values10.1.2. Default Values10.1.3. Types of Input10.1.3.1. Text boxes10.1.3.2. Text areas10.1.3.3. Checkboxes10.1.3.4. Radio buttons10.1.3.5. Hidden10.1.3.6. Selects10.1.4. Working with Multiple Values10.1.5. Validating Data10.1.5.1. Validating checkboxes, radio buttons, and selects10.1.5.2. Validating text boxes and text areas10.1.6. Building a Feet-to-Meters Converter in PHP10.1.7. Building a Time Zone Conversion Utility in PHP10.1.8. Querying the Database with Form Data10.2. Templates10.2.1. Template Engine10.2.2. Installation10.2.2.1. Application level directories10.2.2.2. Creating sample scripts10.2.2.3. Create a sample template10.3. Chapter 10 Questions
11. Practical PHP
11.1. String Functions11.1.1. Formatting Strings for Display11.1.1.1. Using printf11.1.1.2. Padding11.1.1.3. Specifying precision11.1.1.4. Using sprintf11.1.2. Length11.1.3. Changing Case11.1.4. Checking for a String11.1.5. Using String Position and Substring to Extract a Portion of a String11.2. Date and Time Functions11.2.1. Display Formats11.2.2. Arithmetic11.2.3. Validating Dates11.2.4. Using mktime to Create a Timestamp11.3. File Manipulation11.3.1. Functions and Precautions11.3.1.1. Permissions11.3.1.2. Creating files11.3.1.3. Deleting files11.3.1.4. Moving files11.3.2. URL Wrappers11.3.3. Uploading Files11.3.3.1. Accessing the file11.3.3.2. Validation11.4. Calling System Calls11.5. Chapter 11 Questions
12. Modifying MySQL Objects and PHP Data
12.1. Changing Database Objects from PHP12.1.1. Creating a Table12.1.2. Dropping a Table12.1.3. Errors Happen12.2. Manipulating Table Data12.2.1. Adding Data12.3. Displaying Results with Embedded Links12.4. Presenting a Form to Add and Process in One File12.4.1. SQL Injection12.4.2. Cross-Site Scripting Attacks12.5. Updating Data12.6. Deleting Data12.6.1. Generating Unique Identifiers12.7. Performing a Subquery12.8. Chapter 12 Questions
13. Cookies, Sessions, and Access Control
13.1. Cookies13.1.1. Setting a Cookie13.1.2. Accessing a Cookie13.1.3. Destroying a Cookie13.2. PHP and HTTP Authentication13.2.1. Storing a Username and Password in a Database13.3. Sessions13.3.1. Using Sessions13.3.2. Expanding Our Login Example13.3.3. Ending a Session13.3.3.1. Garbage collection13.3.3.2. Setting a session’s timeout13.4. Using Auth_HTTP to Authenticate13.5. Chapter 13 Questions
14. Security
14.1. 14.1.1. Limit Access to Administrative Pages14.1.2. Including Files14.1.3. Storing Passwords in the Database14.1.4. The Problem with Automatic Global Variables14.2. Session Security14.2.1. Session Hijacking and Session Fixation14.2.2. Trusting User Data14.2.3. Shared Hosting Concerns14.2.4. Preventing Access to the Database14.2.5. Blocking Access to the Database for External Hosts14.2.6. Create Separate Database Users14.2.7. Magic Quotes14.3. Chapter 14 Questions
15. Validation and Error Handling
15.1. Validating User Input with JavaScript15.2. Pattern Matching15.2.1. 15.2.1.1. Quantifiers15.2.1.2. Anchors15.2.1.3. Character classes15.2.1.4. Executing pattern matches in PHP15.2.1.5. preg_match15.3. Redisplaying a Form After PHP Validation Fails15.4. Chapter 15 Questions
16. Sample Applications
16.1. Building a Blog16.1.1. Configuration File16.1.2. Page Framework16.1.3. Database16.1.3.1. Sample data16.1.4. Displaying a Postings Summary16.1.5. Displaying a Posting and Its Comments16.1.6. Adding and Changing Posts16.1.7. Adding and Changing Comments16.2. Chapter 16 Questions
17. Finishing Your Journey
17.1. Finding Help on the Web17.1.1. Comments17.1.2. Formatting17.1.2.1. Indenting17.1.2.2. PHP tags17.1.2.3. Templating17.1.2.4. Expressions17.1.2.5. Function calls17.1.2.6. Function definitions17.1.3. Objects17.1.4. Naming17.1.5. Control Structures17.1.5.1. Including or requiring PHP files17.2. Web Sites17.2.1. Chat and Listservs for PHP17.2.2. PHP User Groups17.3. Zend17.4. Lampshade17.5. Chapter 17 Questions
A. Answers to Chapter Questions
A.1. Chapter 1A.2. Chapter 2A.3. Chapter 3A.4. Chapter 4A.5. Chapter 5A.6. Chapter 6A.7. Chapter 7A.8. Chapter 8A.9. Chapter 9A.10. Chapter 10A.11. Chapter 11A.12. Chapter 12A.13. Chapter 13A.14. Chapter 14A.15. Chapter 15A.16. Chapter 16A.17. Chapter 17
About the Authors
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Content preview from Learning PHP and MySQL

Chapter 15. Validation and Error Handling

We’ve already discussed performing validation within our PHP code. In this chapter, we’ll explore our options for validating form data before a form submission. We’ll also discuss what to do when validation fails, and how to process other errors. We can check information on the client side in the user’s browser using JavaScript. We can also check the data when it’s submitted directly in PHP.

There’s some information that can go out as part of a production error message that is not harmful for end users. For example, it’s OK to say that you’re having a problem connecting to your database. However, you don’t want to reveal more information than is necessary in an error messages that may go out to end users. For example, you don’t want to disclose the IP address of your database and certainly not the username that was attempted when you tried to connect. Both of those could aid a potential attacker in breaking in when the database comes back online.

Validating User Input with JavaScript

On the client side, your best tool for validating data is JavaScript. JavaScript is different than PHP, because it’s designed to execute in the user’s browser instead of on the server. Because it executes in the client’s computer, JavaScript is not allowed to access anything that could be a security risk, such as the local filesystem or network resources. JavaScript is primarily used in web pages. Although its name sounds like Java, it has no relationship to ...

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Learning PHP and MySQL

by Michele E. Davis, Jon A. Phillips

Chapter 15. Validation and Error Handling

Validating User Input with JavaScript

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