CodeIgniter:通过来自同一表单的两个数组填充两个表

我尝试了以下操作，但令人惊讶的是，它只填充第一个表（new_guest），而只向另一个表写入零值（new_reservation）。如何正确配置？

控制器：

function guest_checks_in() {    
    $data_guest = array (
        'guest_title' => $this->input->post('guest_title'),
        'guest_name' => $this->input->post('guest_name'),
        'guest_gender' => $this->input->post('guest_gender'),
        'guest_phone' => $this->input->post('guest_phone'),
        'guest_email' => $this->input->post('guest_email'),
        'guest_address' => $this->input->post('guest_address'),
        'guest_province' => $this->input->post('guest_province'),
        'guest_country' => $this->input->post('guest_country'),
        'guest_postal_code' => $this->input->post('guest_postal_code'),
        'guest_dob' => $this->input->post('guest_dob'),
        'guest_nic_pp_dl' => $this->input->post('guest_nic_pp_dl')
    );
    $data_reservation = array (
        'room_type' => $this->input->post('room_type'),
        'meal_type' => $this->input->post('meal_type'),
        'bed_type' => $this->input->post('bed_type'),
        'ext_beds' => $this->input->post('ext_beds'),
        'number_of_guests' => $this->input->post('number_of_guests'),
        'start_date' => $this->input->post('start_date'),
        'end_date' => $this->input->post('end_date'),
        'reservation_duration' => $this->input->post('reservation_duration'),
        'room_number' => $this->input->post('room_number'),
        'total' => $this->input->post('total')
    );
$this->reservations_model->add_guests($data_guest);
$this->reservations_model->add_reservations($data_reservation);
$this->confirm_check_in();
}

型号：

class Reservations_model extends CI_Model {
function add_guests($data_guest) {
    $this->db->insert('new_guest', $data_guest);
    return;
}
function add_reservations($data_reservation) {
    $this->db->insert('new_reservation', $data_reservation);
    return;
}
}