@SuppressWarnings("resource")
	public int getEmployeeNo(DataSource ds) {
		while (true) {
			System.out.print("Back = 0. Enter employee no or doctor name: ");
			Scanner s = new Scanner(System.in);
			String doctor_info = s.nextLine();
			try {
				int option = Integer.parseInt(doctor_info);
				if (option == 0) {
					return 0;
				}
			} catch (Exception e) {
			}
			ResultSet rs = ds.checkDoctor(doctor_info);
			Vector<Doctor> doctors = ds.getDoctorList(rs);
			int isExist = doctors.size();
			if (isExist == 0) {
				System.out.println("Doctor: " + doctor_info
						+ " does not exist.");
				continue;
			} else {
				Helper.printDoctors(doctors);
				if (isExist > 1) {
					return getEmployeeNo(ds);
				} else {
					return doctors.listIterator(0).next().getEmployee_no();
				}
			}
		}
	}