Select query with else

In CodeIgniter Query Builder style:

PHP Code:

$this->db
->select('tb_kunde_id')
->from('db_kunde')
->where('tb_kunde_vorname',$tb_kunde_vorname)
->where('tb_kunde_nachname', $tb_kunde_nachname)
->where('tb_kunde_land', $tb_kunde_land);

$query = $this->db->get();

if ($query->num_rows() == 0) {
  $this->db->insert('db_kunde',$client_data);
  $id_kunde = $this->db->insert_id();
}
else {
  $id_kunde = $query->row()->tb_kunde_id;
}