1$table = "my_table";
2$id = 1;
3$update = ["status"=>"working"];
4//Edit just above /\ if you don't need extra "where" clause
5$query = $this->db->select()
6 ->from($table)
7 ->where('id', $id)
8 ->get_compiled_select();
9$data = $this->db->query("$query FOR UPDATE")->row_array();
10$this->db->where('id', $data['id'])->update($table,$update);