public boolean update(User user) {

    if (user.getUser_name() != null && user.getUser_name() != "") {
      dbOperator.update(
          String.format(UPDATE_USER, "user_name", user.getUser_name(), user.getUser_id()));
    }
    if (user.getDepartment_id() > 0) {
      dbOperator.update(
          String.format(UPDATE_USER, "department_id", user.getDepartment_id(), user.getUser_id()));
    }
    if (user.getStaff_position() != null && user.getStaff_position() != "") {
      dbOperator.update(
          String.format(
              UPDATE_USER, "staff_position", user.getStaff_position(), user.getUser_id()));
    }
    if (user.getPwd() != null && user.getPwd() != "") {
      dbOperator.update(String.format(UPDATE_USER, "pwd", user.getPwd(), user.getUser_id()));
    }
    return true;
  }
 public boolean add(User user) {
   return dbOperator.add(
       String.format(
           ADD_USER,
           user.getUser_id(),
           user.getUser_name(),
           user.getPwd(),
           user.getDepartment_id() > 0 ? user.getDepartment_id() : null,
           user.getStaff_position() != null ? "'" + user.getStaff_position() + "'" : null,
           user.getTotal_annual_leave() != 0 ? user.getTotal_annual_leave() : null));
 }