Computer Education World

3.1 INTRODUCTION
PHP 3 is the version that introduced support for object-oriented programming
(OOP). Although useable, the support was extremely simplistic and not very
much improved upon with the release of PHP 4, where backward compatibil-
ity was the main concern. Because of popular demand for improved OOP sup-
port, the entire object model was completely redesigned for PHP 5, adding a
large amount of features and changing the behavior of the base “object” itself.
If you are new to PHP, this chapter covers the object-oriented model.
Even if you are familiar with PHP 4, you should read it because almost every-
thing about OOP has changed with PHP 5.
When you finish reading this chapter, you will have learned
The basics of the OO model
Object creation and life-time, and how it is controlled
The three main access restriction keywords (public, protected, and
private)
The benefits of using class inheritance
Tips for successful exception handling