PHP provides a vast library of built-in functions that let you perform all sorts of tasks without having to look to third party software vendors for a solution. The online reference to these functions provided by the PHP Official Website is second to none. Obtaining detailed information about a function is as simple as opening your browser and typing:
http://www.php.net/functionname
As a result of the convenience of this facility, we have judged that a complete PHP function reference is beyond the scope of this book. All the same, this appendix contains a reference to those PHP functions specifically designed to interact with MySQL databases, so that if you use this book as your primary reference while building a database-driven Website, you won't have to look elsewhere for the information you need.
This list of functions and their definitions are current as of PHP 4.3.0.