Çalışan versiyon.
$userquoted = $this->db->quote($user);
$passquoted = $this->db->quote($pass);

$login= $this->db->prepare("SELECT id, username, password, factory_id, email FROM users WHERE username = $userquoted AND password = SHA1($passquoted) LIMIT 1");

$login->setFetchMode(PDO::FETCH_ASSOC);
$login->execute();



/*Çalışmayan Parametreli versiyon */
Parametreli kullanımda string sorunu geliyor çünkü PDO::quote(); stringi tek tırnak içerisine alıyor.

$userquoted = $this->db->quote($user);
$passquoted = $this->db->quote($pass);

$login= $this->db->prepare("SELECT id, username, password, factory_id, email FROM users WHERE username = :user AND password = SHA1(:pass) LIMIT 1");

$login->setFetchMode(PDO::FETCH_ASSOC);
$login->execute(
           array(
                ":user"=>$userquoted,
                ":pass"=>$passquoted
            )
);