The entire contents of this edition of the book were updated to correspond to version 6 of PHP and version 5 of MySQL. Approximately 50% of the material requires version 5 or later of PHP, mostly because the book only uses the Improved MySQL functions, added in PHP 5 and MySQL 4.1. Another 20% or so of the material requires version 6 of PHP. This 20% reflects the bulk of the new material in this edition.

In terms of what’s new, there are five entirely new chapters. Chapter 4: Introduction to MySQL takes some material out of the previous edition, breaks it down into smaller steps, and adds a discussion of phpMyAdmin. Chapter 12: Security Methods is entirely new, focusing on addressing specific security concerns (although some of the material is from previous editions). Chapter 13: Perl-compatible Regular Expressions is also entirely new, discussing a different (more or less preferred) type of regular expressions. The bulk of the new Chapter 14: Making Universal Sites is Unicode, support for which has been added in PHP 6. The chapter also has discussion of using time zones in MySQL and locales in PHP. Chapter 15: Example—Message Board is a new example chapter, creating a mulit-lingual forum.

In terms of revised content, Chapter 6: Advanced SQL and MySQL uses an entirely new example–a message board/forum–for all of the steps and SQL queries. Every chapter that uses both PHP and MySQL together, which is about half the book, has been updated to use the Improved MySQL functions instead of the older MySQL functions. Chapter 11: Cookies and Sessions handles the login/logout process a bit differently. Chapter 16: Example—User Registration has been updated to support different levels of users. Chapter 17: Example—E-Commerce and a couple of other chapters make more use of sticky forms, a concept that’s much more thoroughly covered in this edition. Finally, the Windows installation instructions in Appendix A: Installation have been updated to use XAMPP, a truly great (and free!) product.