public void updatePatient(int health_care_no, String field, String value) {
		// UPDATE table_name
		// SET column1=value1,column2=value2,...
		// WHERE some_column=some_value;

		String patientUpdate = "";

		if (field.equals("name") || field.equals("address")
				|| field.equals("phone")) {
			patientUpdate = "UPDATE patient SET " + field + "='" + value
					+ "' WHERE health_care_no=" + health_care_no;
		} else if (field.equals("birth_day")) {
			patientUpdate = "UPDATE patient SET " + field + "=to_date('"
					+ value + "', 'YYYY-MM-DD') WHERE health_care_no="
					+ health_care_no;
		}

		try {
			stmt.executeUpdate(patientUpdate);
			con.commit();
			System.out.println("Patient updated.");
		} catch (SQLException e) {
			System.out.println("Sorry, could not update " + field);
		}
	}