mysqli_bind_param()已经被废弃并且将会被移除。 那现在用什么代替？

<code><?php    
$username = "aaa";    
$pwd = "pwd";    
$sql = "SELECT * FROM table WHERE username = ? AND pwd = ?";    
bindParam($sql, 1, $username, 'STRING');  //以字符串的形式.在第一个问号的地方绑定$username这个变量    
bindParam($sql, 2, $pwd, 'STRING');       //以字符串的形式.在第二个问号的地方绑定$pwd这个变量    
echo $sql;    
?></code>

<code><?php    
$username = "aaa";    
$pwd = "pwd";    
$sql = "SELECT * FROM table WHERE username = ? AND pwd = ?";    
bindParam($sql, 1, $username, 'STRING');  //以字符串的形式.在第一个问号的地方绑定$username这个变量    
bindParam($sql, 2, $pwd, 'STRING');       //以字符串的形式.在第二个问号的地方绑定$pwd这个变量    
echo $sql;    
?></code>

<code class="php">$username = "aaa";    
$pwd = "pwd";    
$sql = "SELECT * FROM table WHERE username = ? AND pwd = ?";   
$sth = $dbh->prepare($sql);
$sth->bindParam(1, $username, PDO::PARAM_STR);
$sth->bindParam(2, $pwd , PDO::PARAM_STR, 12);
$sth->execute();</code>