Using php with PDB

Hi

I use commands such as those below to access the Participants DataBase

$boatdata = Participants_Db::get_participant($user_id);
$username = $boatdate[‘username’];$user_id = Participants_Db::get_record_id_by_term(‘username’, $wp_username);

What I would ask

is there a list of php commands that are available to work with PDB, or where can I get further information with regards to working with PDB using php.

Thanks