CodeIgniter PDO database driver not working

I'm trying to use the PDO MySQL driver in my CodeIgniter application. This is my database config: ``` $active_group = 'default'; $active_record = TRUE; $db['default']['hostname'] = 'localhost'; $db['default']['username'] = 'root'; $db['default']['password'] = ''; $db['default']['database'] = 'testdatabase'; $db['default']['dbdriver'] = 'pdo'; $db['default']['dbprefix'] = ''; $db['default']['pconnect'] = TRUE; $db['default']['db_debug'] = TRUE; $db['default']['cache_on'] = FALSE; $db['default']['cachedir'] = ''; $db['default']['char_set'] = 'utf8'; $db['default']['dbcollat'] = 'utf8_general_ci'; $db['default']['swap_pre'] = ''; $db['default']['autoinit'] = TRUE; $db['default']['stricton'] = FALSE; ``` However, I'm getting this error when I load a controller: Fatal error: Uncaught exception 'PDOException' with message 'invalid data source name' in C:\xampp\htdocs\testsite\system\database\drivers\pdo\pdo_driver.php:114 I've checked the data source using `die($this->hostname);` in `pdo_driver.php` and it's coming out as: ``` localhost;dbname=testdatabase ``` so it is getting the correct database name. The database exists and I do have MySQL running. What could be going wrong here? Thank you.