Question

I am trying to implement singleton pattern and i am getting the following error

Fatal error: Access level to Database::__construct() must be public
(as in class PDO) in /config/database.php on line 29

<?php

class Database extends PDO
{
    private static $instance;

    private function __construct()
    {

            return parent::__construct(
                    "mysql:host=localhost;dbname=live",
                    "root",
                    "root"
            );

    }

    public function getInstance() {
        if(self::$instance === null) {
            self::$instance = new Database();
        }
        return self::$instance;
    }

    public function __clone() 
    {
        die(__CLASS__ . ' class cant be instantiated. Please use the method called getInstance.');
    }
}


$mySingleton = Database::getInstance();

var_dump($mySingleton);

?>

Answer 1

You can’t change the Access level for a override method.

Instead of extending PDO, you could just have a PDO instance in Database.
Composition is more flexible than inheritance.