是否有可能重载PHP

Question

中的构造函数，例如在C＃中，您可以使用相同的方法名重载方法，但PHP呢？

class Database { 
    private $dsn; 
    private $host; 
    private $user; 
    private $password; 
    private $enckey; 

    function __construct($dbname, $host, $user, $password) { 
     $this->dsn = "mysql:dbname=" . $dbname . ';host=' . $host; 
     $this->user = $user; 
     $this->password = $password; 
} 
    function __construct($dbname, $host, $user, $password, $enckey) { 
     $this->dsn = "mysql:dbname=" . $dbname . ';host=' . $host; 
     $this->user = $user; 
     $this->password = $password; 
     $this->enckey = $enckey; 
    } 
} 

Answer 1

这是什么意思？

class Database { 
    private $dsn; 
    private $host; 
    private $user; 
    private $password; 
    private $enckey; 

    function __construct($dbname, $host, $user, $password, $enckey = null) { 
     $this->dsn = "mysql:dbname=" . $dbname . ';host=' . $host; 
     $this->user = $user; 
     $this->password = $password; 
     $this->enckey = $enckey; 
    } 
}