ok here is my prediciment. i have just been recently working with php classes and oop.

i have a system class that i have contain all the other classes (they extend system)

Class System

• database extends system
• security extends system

how can i get the security and database classes to be able to access each other's functions without including each class file in each function that i want to use that class in

ex. i want to use
from my security class without including database.class.php in each function i want to call something from the database in

if someone could shed some light on this i would really really appriciate it.

thanks