PHP PDO UPDATE not updating data - php

Question

I am having a tough time updating data using PDO. These are the two options that i've tried. None has actually updated the database, however.
Query 1:
$dateLastLoggedIn = date("Y-m-d H:i:s");
$username = mysql_real_escape_string($_POST['User']);
$sth = $dbh->prepare("UPDATE users SET dateLastLoggedIn = ? WHERE username = ?");
$sth->execute(array($dateLastLoggedIn,$username));
print_r($sth->queryString); just prints out UPDATE users SET dateLastLoggedIn = ? WHERE username = ?
Query 2:
$dateLastLoggedIn = date("Y-m-d H:i:s");
$username = mysql_real_escape_string($_POST['User']);
$sql = "UPDATE users SET dateLastLoggedIn = '".$dateLastLoggedIn."' WHERE username = '".$username."'";
$sth = $dbh->prepare($sql);
$sth->execute();
print_r($sth->queryString); prints out UPDATE users SET dateLastLoggedIn = '2012-08-03 13:36:32' WHERE username = 'testuser'
The second option generates the correct query but it doesn't actually update the data. I can manually run the generated script and it works, but not through the execute(). Anything i'm doing wrong? I'm still new to PDO, so it may be a simple fix.
SOLVED: see my last comment under the accepted answer.

Answer 1

getting connection :
function getConnection(){
$dbhost="127.0.0.1";
$dbuser="application";
$dbpass="password";
$dbname="abc";
$dbh = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbuser, $dbpass);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
try {
$dbh = getConnection();
$sth = $dbh->prepare("UPDATE users SET dateLastLoggedIn = :dateLastLoggedIn WHERE username = :username ");
$sth->bindParam('dateLastLoggedIn',$dateLastLoggedIn);
$sth->bindParam('username',$username );
$sth->execute();
$dbh = null; // after done
} catch(PDOException $e) {// simple exception handling
error_log($e->getMessage(), 3, '/var/tmp/php.log');
echo '{"error":{"text":'. $e->getMessage() .'}}';
}
Also, try to wrap this in try catch to see the error

Answer 2

print_r($sth->queryString); just prints out UPDATE users SET dateLastLoggedIn = ? WHERE username = ?
That's what will happen with PDO prepared queries.
If you're using PDO, mysql_real_escape_string isn't going to work. At all. It requires an existing connection via mysql_connect. Your username value is effectively blank.