group_by($by[, $escape = NULL])

$this->db->call_function(); This function enables you to call PHP database functions that are not natively included in CodeIgniter,

update([$table = ''[, $set = NULL[, $where = NULL[, $limit = NULL]]]])

dbprefix([$table = ''])

cache_delete([$segment_one = ''[, $segment_two = '']])

db_pconnect()

start_cache()

modify_column($table, $field)

CodeIgniter’s database abstraction allows you to use transactions with databases that support transaction-safe table types. In MySQL, you’ll need to be running InnoDB or BDB

add_column($table[, $field = array()[, $_after = NULL]])