Php - 没有使用PDO更新mysql中的行

I want to update a row in PHP by using PDO... but couldn't do that, & not giving an error too...

my SQL update function in php: // PDO Function To Handle Prepared Statements (FOR ALL QUERY)

function sql($DBH, $query, $params, $return) {
        try {
            // Prepare statement
            $STH = $DBH->prepare($query);
            // Execute statement
            $STH->execute($params);
            // Decide whether to return the rows themselves, or just count the rows
            if ($return == "rows") {
                return $STH->fetchAll();
            }
            elseif ($return == "count") {
                return $STH->rowCount();
            }
        }
        catch(PDOException $e) { 
            file_put_contents('PDOErrors.txt', $e->getMessage(), FILE_APPEND); # Errors Log File
        }
    }

my PDO SQL code for the update:

sql($DBH, "UPDATE tbl_causes SET title=?,para1=?,bullets=?,img=? WHERE id = ?", array($title, $para1, $bullets, $img, $id), "rows");