php - Autoloading a database class within another class? -

i have 2 classes, database , user. in database class have function connect database. wanting able have connection database within user class. doing in user class:

class user {      function __construct()      {         require_once 'database.class.php';         $dbh = new database();         $dbh->connect();     }      function register_user()     {         $dbh->prepare('insert users values (:username, :password, :forename, :surname)');         $dbh->execute(array(':username' => 'administrator', ':password' => '5f4dcc3b5aa765d61d8327deb882cf99', ':forename' => 'richie', ':surname' => 'jenkins'));     } } 

i following error:

php fatal error: call member function prepare() on non-object

you should read "scope." $dbh declared locally in __construct().

rectifying easy. add

class user {    private $dbh; 

and wherever have $dbh change $this->dbh. may read $this , member variables well.