调用一个成员函数bindParam（）是什么？

Question

My php code is given below.

class Login {

    public function logar($login, $senha){
        $db = new Database();
        try{
            $conn = $db->connect();
            $prepare = $conn->prepare("SELECT * FROM account WHERE Login = :login AND Passwd = :senha");
            $prepare->bindParam(':login', $login, PDO::PARAM_STR);
            $prepare->bindParam(':senha', $senha, PDO::PARAM_STR);
            $prepare->execute();
            $ranking = $prepare->rowCount();
            if ($ranking >= 1){
                return "<div class='n_ok' style='margin:9px 15px;'><p>Successfully.</p></div>";
            }else{
                return "<div class='n_error' style='margin:9px 15px;'><p>Usuario ou senha incorreta.</p></div>";
            }
        }catch(PDOException $e){
            echo "Erro: ".$e->getMessage();
        }
    }

}

While i am running this below error is occured

Fatal error: Call to a member function bindParam() on boolean in C:\AppServ\www\class\Login.class.php on line 9**

Answer 1

What does "new Database()" refer to. I hope it should return PDO Connection.

Below Code will work fine for sure

class Login {
    public function logar($login, $senha){
        $conn = new PDO('mysql:host=dbhostname;dbname=databasename', $user, $pass);
        try{
            $prepare = $conn->prepare("SELECT * FROM account WHERE Login = :login AND Passwd = :senha");
            $prepare->bindParam(':login', $login, PDO::PARAM_STR);
            $prepare->bindParam(':senha', $senha, PDO::PARAM_STR);
            $prepare->execute();
            $ranking = $prepare->rowCount();
            if ($ranking >= 1){
                return "<div class='n_ok' style='margin:9px 15px;'><p>Successfully.</p></div>";
            }else{
                return "<div class='n_error' style='margin:9px 15px;'><p>Usuario ou senha incorreta.</p></div>";
            }
        }catch(PDOException $e){
            echo "Erro: ".$e->getMessage();
        }
    }

}