Login script using PDO extension not working - php

Question

I am unsure if I am doing it properly but I just started working with PDO and I am not able to get my code to work. I continue to get the error "sorry could not connect" and I am unable to figure out what is wrong.
Included below is the code that I am using:
function doRun( $data )
{
try
{
$db = new PDO('mysql:host=localhost;dbname=testData', 'root', 'root');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$stmt = $db->prepare(' SELECT
username, pass
FROM
testTable
WHERE
username = :name
AND
pass = :pass
');
$stmt->bindParam(':name', $username, PDO::PARAM_STR);
$stmt->bindParam(':pass', $pass, PDO::PARAM_STR);
$stmt->execute();
//$result = $stmt->fetchAll(PDO::FETCH_ASSOC);
$result = $stmt->fetchColumn();
if($result == false)
{
echo 'sorry could not connect';
}
else
{
$_SESSION['username'] = $user;
echo 'logged in as' . $user;
}
}
catch (PDOException $e)
{
echo "throw";
}
$db = NULL;
}

Answer 1

This would give you 0 rows as it seems that $username and $pass are not defined:
$stmt->bindParam(':name', $username, PDO::PARAM_STR);
$stmt->bindParam(':pass', $pass, PDO::PARAM_STR);
^^^^^^^^^
You probably want some elements from $data variable you are feeding to the function as a username and password.
Later on you are using a variable $user that is undefined as well.
What does $data contain?

Answer 2

The reason that you are "unable to connect", even though you are connecting but you're not finding a match, is because your user variables are not defined.
Try the following solution:
<?php
function doRun( $data )
{
$msg = '';
$username = isset($_POST['name']);
$pass = isset($_POST['pass']);
try
{
$db = new PDO('mysql:host=localhost;dbname=testData', 'root', 'root');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$stmt = $db->prepare('
select
username
,pass
from
testTable
where
username = :name
and pass = :pass
');
$stmt->execute(array(':name' => $username, ':pass' => $pass);
$result = $stmt->fetchAll();
if(!empty($result)){
$_SESSION['username'] = $user;
$msg = "logged in as $user";
}else{
$msg = "Unable to connect";
}
} catch (PDOException $e) {
echo "Error: $e";
}
echo $msg
$db = NULL;
}
?>