无法访问子类中的pdo连接

Question

I am having a problem making a pdo connection accessible over extended classes eg :

class Model {

public $connection;

public function __construct(PDO $connection = null)
{
    global $config;
    $this->connection = $connection;
    if ($this->connection === null) {
        $this->connection = new PDO(
        'mysql:host='.$config['db_host'].';dbname='.$config['db_name'], $config['db_username'], $config['db_password']);
        $this->connection->setAttribute(
            PDO::ATTR_ERRMODE, 
            PDO::ERRMODE_EXCEPTION
        );
    }
}

And another class extending model

class User extends Model { 
    public function someFunction(){
        // how can I access the pdo connection in the parent constructer here?
    }
}

Thats the crux of the issue I wan't to access the parent connection created in the constructor in child classes, guidance much appreciated.

Answer 1

As constructors are not implicitly called in PHP, you need to add some lines at least, and afterwards just use $this :

class User extends Model {

    public function __construct(PDO $connection = null) {
         parent::__construct($connection);
    }

    public function someFunction(){
         // access the pdo connection in the parent here:
         $this->connection->.....

    }
}