Hi,

I am making a simple PHP framework, this has a 'base' class, then includes other classes, like a database abstraction class and a form validation class.

I have got the classes all working and including, but I cant seam to reference another sub class from with in a sub class?

example:
PHP Code:
<?php

    
require_once('db.php'); // databse class
    
require_once('validation.php'); // validation class
    
    
class Base {
        
        function 
Base() {
            
            
// load extending classes
            
$this->db = new Db();
            
$this->validation = new Validation();
            
        }
        
        function 
test() {
            
            
print_r($this->validation->run());
            
        }
    }
    
    class 
Db extends base {
        
        function 
Db() {
            
        }
        
        function 
query($sql) {
            
//
        
}
    }
    
    class 
Validation extends base {
        
        function 
Validation() {
            
        }
        
        function 
run() {
            
            
$this->db->query("SELECT * FROM `table`");
            
        }
    }
What I want to be able to do, is call a sub function from another sub function.

for example:
PHP Code:
<?php

// load main class, and my two sub classes
$instance = new Base();

// fire a function which has access to my validation class, and my DB class.
$instance->test();
however I get the PHP Error

Fatal error: Call to a member function query() on a non-object

I have tried using the parent:: tag at the top of my subclasses like below, but that didn't seam to help;
PHP Code:
    class Db extends base {
        
        function 
Db() {
            
parent::System();
        }