I am new to SO but I have faced this problem too. Many people find it troublesome to switch from mysql_* to PDO.
In my case I was using a separate connection.php that stored functions to connect to database and returned the handle
function connect() { $cn = mysql_connect("localhost","username","pass" ); $select = mysql_select_db("dbname", $cn); return($cn); } //For PDO function pdoconnect() { $db=""; try { $db=new PDO("mysql:host=localhost;dbname=dbname", "username", "pass"); $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); } catch (PDOException $er) { print("errr".$er."<br />"); return(1); } return($db); }
while for old functions I used $cn=connect();.
I switched to $cn=pdoconnect(); for new ones.
This worked because I was already using connect.php in old files as well.