BONUS SUKI
POS

helper/DatabaseHelper.javapublic static synchronized Connection getConnect() {
    if (conn == null) {
        try {
            conn = DriverManager.getConnection(URL);
            Statement pragma = null;
            try {
                pragma = conn.createStatement();
                pragma.execute("PRAGMA foreign_keys = ON");
            } finally {
                closeQuietly(null, pragma);
            }
            createTablesIfEmpty();   // ไฟล์ใหม่ = สร้างตาราง + mock data
        } catch (SQLException ex) {
            LOG.log(Level.SEVERE, "เชื่อมต่อไม่สำเร็จ", ex);
        }
    }
    return conn;
}

model/Member.javapublic class Member {
    private String memberId;      // ← Member_ID (PK เช่น M001)
    private String memberName;    // ← Member_Name
    private String memberPhoneNo; // ← UNIQUE 10 หลัก
    private String memberAddress; // ← NULL ได้
    private int pointBalance;

    // constructor 3 แบบ + getter/setter (Ctrl+I)

    public static Member fromRS(ResultSet rs) throws SQLException {
        Member m = new Member();
        m.setMemberId(rs.getString("Member_ID"));
        m.setMemberName(rs.getString("Member_Name"));
        m.setMemberPhoneNo(rs.getString("Member_PhoneNo"));
        m.setMemberAddress(rs.getString("Member_Address"));
        m.setPointBalance(rs.getInt("Point_Balance"));
        return m;
    }
}

dao/MemberDao.java@Override
public Member get(String id) {
    String sql = "SELECT * FROM Member WHERE Member_ID = ?";
    Connection conn = DatabaseHelper.getConnect();
    PreparedStatement stmt = null;
    ResultSet rs = null;
    try {
        stmt = conn.prepareStatement(sql);
        stmt.setString(1, id);
        rs = stmt.executeQuery();
        return rs.next() ? Member.fromRS(rs) : null;
    } catch (SQLException ex) {
        LOG.log(Level.WARNING, "get(" + id + ") ล้มเหลว", ex);
        return null;
    } finally {
        DatabaseHelper.closeQuietly(rs, stmt);
    }
}

ui/MemberPanel.java (ส่วนที่เขียนเอง · ย่อ)public MemberPanel() {
    initComponents();
    tblMember.getSelectionModel()
        .addListSelectionListener(this::tblMemberValueChanged);
    loadTable(memberService.getAll());
}

private void loadTable(List<Member> list) {
    DefaultTableModel model = Form.readOnlyModel(
            "รหัส", "ชื่อ-นามสกุล", "เบอร์โทร", "แต้ม");
    for (Member m : list) {
        model.addRow(new Object[]{m.getMemberId(), m.getMemberName(), ...});
    }
    tblMember.setModel(model);
}

private void btnSaveActionPerformed(ActionEvent evt) {
    try {
        if (id == null) memberService.add(m);
        else memberService.edit(m);
        loadTable(memberService.getAll());
    } catch (IllegalArgumentException ex) {
        JOptionPane.showMessageDialog(this, ex.getMessage());
    }
}

Session จำว่าใครล็อกอินอยู่ ทุกหน้าเรียก Session.isManager() ได้โดยไม่ต้องส่งต่อทาง constructor

service/LoginService.javapublic UserAccount login(String username,
        String password, String role) {
    UserAccount user = userAccountDao.getByUsername(username);
    if (user == null
            || !user.getPassword().equals(password)
            || !user.getRole().equals(role)) {
        return null;
    }
    Employee employee = employeeDao.get(user.getEmpId());
    Session.login(user, employee);
    return user;
}

ui/LoginFrame.java (ย่อ)private void btnLoginActionPerformed(ActionEvent evt) {
    String role = tglManager.isSelected()
            ? UserAccount.ROLE_MANAGER : UserAccount.ROLE_EMPLOYEE;
    UserAccount user = loginService.login(...);
    if (user == null) {   // แจ้งเตือนแล้วล้างช่องรหัส
        return;
    }
    new MainFrame().setVisible(true);
    dispose();
}

service/PosService.java (ย่อ)public Bill checkout(...) throws SQLException {
    Connection conn = DatabaseHelper.getConnect();
    conn.setAutoCommit(false);
    try {
        double discount = promotionService.calcDiscount(...);
        double net = round2(total - discount);
        if (received < net) {
            throw new IllegalArgumentException("รับเงินไม่พอ ...");
        }
        require(billDao.update(bill) != null, "บันทึกบิลไม่สำเร็จ");
        stockItemService.deductByBom(orderId);
        memberService.addPoints(memberId, net);
        diningTableDao.updateStatus(tableId, DiningTable.STATUS_VACANT);
        conn.commit();
        return bill;
    } catch (RuntimeException | SQLException ex) {
        conn.rollback();
        throw ex;
    } finally {
        conn.setAutoCommit(true);
    }
}