title: PDO prepared statement with placeholder not work
body: <p>i have some problems with execute a PDO.
  No error, just nothing happens. The code looks like:</p>
  
  <pre><code>$stmt = $dbh-&gt;prepare("INSERT INTO `member_accounts` ('firstname','lastname','email','password') VALUES (:fname,:lname,:e,:pw)");
                   $arr = array(
                      ':fname' =&gt; $_POST['firstname'],
                      ':lname' =&gt; $_POST['lastname'],
                      ':e' =&gt; $_POST['email'],
                      ':pw' =&gt; $_POST['password'],
                      );
                   $stmt-&gt;execute($arr);
  </code></pre>
  
  <p>Anyone see the problem? I'm to new at PDO.. Thanks</p>