This document discusses an agenda for a session on beginning PHP, including more topics on object-oriented programming (OOP) such as inheritance, subclasses, extending functionality, and single inheritance in PHP. It also covers visibility in classes as public, protected, or private and why non-public visibility is used, such as with getters and setters to inject behavior and protect state from unrelated code.

1. Beginning PHP
Session #7
January 12, 2011
Josh Butts

2. Agenda
• More OOP
• Database Object
• Update Vanity with Objects

3. Inheritance
• Objects can inherit behavior and default
state from other objects
• A class that inherits from another class is
called a sublcass
• When we subclass something, we “extend”
it
• Subclasses may add or change functionality

4. PHP’s Single Inheritance
• A class may have only one parent class
• Any given class can have many subclasses

5. Single Inheritance
Person
Student
Honors Exchange
Student Student

6. Visibility
• Public - anyone can call a method or modify
a property
• Protected - only this class or subclasses
may call the method or modify the
property
• Private - only this class may modify or call

7. Why use non-public?
• Getters & Setters can inject behavior
• Protects unrelated code from changing
your state