不能訪問子類PDO連接

Question

我有一個問題作出PDO連接訪問在擴展類，例如：

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 
     ); 
    } 
} 

而另一擴展類模型

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

這就是癥結我不想訪問在子類中的構造函數中創建的父連接的問題，非常感謝。

Answer 1

由於構造函數不是在PHP隱式調用，您需要添加至少某些行，事後只使用$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->..... 

    } 
}