Hi, I'm new to PHP oop stuff.

I'm trying to create class database and call other classes from it. Am I doing it the right way?

class database:

class database extends mysqli {

private $classes = array();

public function __construct() {
parent::__construct('localhost', 'root', 'password', 'database');
    if (mysqli_connect_error()) {
    $this->error(mysqli_connect_errno(), mysqli_connect_error());
    }
}

public function __call($class, $args) {
    if (!isset($this->classes[$class])) {
    $class = 'db_'.$class;
    $this->classes[$class] = new $class(); 
    }
return $this->classes[$class];
}

private function error($eNo, $eMsg) {
die ('MySQL error: ('.$eNo.': '.$eMsg);
}

}

class db_users:

class db_users extends database {

public function test() {
echo 'foo';
}

}

and how I'm using it

$db = new database();
$db->users()->test();

Is it the right way or should it be done another way?

Thank you.