Undefined Variable in Derivative Class with Private Variable in PHP? - php

Question

I'm attempting to create a mysql query using OOP in PHP. In the code below the class "database_disconnection" does not toss any errors or notices, however the last class "database_query" gives me a notice that $database_handle is undefined. I have no idea what's causing this as I created the database_query class as a derivative class of database_connection, which include the $database_handle variable as private. Any help would be greatly appreciated!
Instantiating the objects:
include("includes/database_classes.php");
new database_connection;
new database_query('SELECT * FROM users');
and the classes:
<?php
/*----------------------------------------------------------------------------------------------------*/
class database_connection
{
private $username = 'root';
private $password = '';
private $hostname = 'localhost';
private $database = 'assistant';
private $database_handle;
function connect()
{
try
{
$database_handle = new PDO("mysql:host=$hostname;dbname=$database", $username, $password);
}
catch (PDOException $e)
{
print "Error!: " . $e ->getMessage() . "<br/>";
die();
}
}
}
/*----------------------------------------------------------------------------------------------------*/
class database_disconnection extends database_connection
{
function disconnect()
{
$database_handle = null;
}
}
/*----------------------------------------------------------------------------------------------------*/
class database_query extends database_connection
{
private $mysql_statement;
function __construct( $mysql_statement )
{
$this->mysql_statement = $mysql_statement;
foreach($database_handle->query("$mysql_statement") as $row) {
print_r($row);
}
}
}
/*----------------------------------------------------------------------------------------------------*/
?>

Answer 1

In your database_query constructor, you're attempting to use $database_handle before initializing it. If you notice, you only initialize in the connect function of your parent class (database_connection).
Either call connect before trying to refer to it, or initialize it in the parent's constructor, and call it (parent::__construct();).