diff --git a/HrmsEmployeeDAO.cs b/HrmsEmployeeDAO.cs
new file mode 100644
index 0000000..b55e2bd
--- /dev/null
+++ b/HrmsEmployeeDAO.cs
@@ -0,0 +1,130 @@
+using MySql.Data.MySqlClient;
+using System;
+
+namespace HanvonF710XAttendanceService
+{
+    /// <summary>
+    /// HRMS employee row used for Hanvon display name and portal photo URL.
+    /// Device enroll/serial must NOT be treated as employee.id.
+    /// </summary>
+    internal sealed class HrmsEmployeeInfo
+    {
+        public HrmsEmployeeInfo(string employeeId, string serialNumberInt, string concatenatedName, string department = "")
+        {
+            EmployeeId = employeeId ?? "";
+            SerialNumberInt = serialNumberInt ?? "";
+            ConcatenatedName = concatenatedName ?? "";
+            Department = department ?? "";
+        }
+
+        /// <summary>employee.id — used for portal photo URL only.</summary>
+        public string EmployeeId { get; }
+
+        /// <summary>employee.serial_number_int — matches device / attendance_machine_user.serial_number.</summary>
+        public string SerialNumberInt { get; }
+
+        /// <summary>employee.concatenated_name — Hanvon user display name.</summary>
+        public string ConcatenatedName { get; }
+
+        /// <summary>Department display name when available; otherwise department_id.</summary>
+        public string Department { get; }
+    }
+
+    internal sealed class HrmsEmployeeDAO
+    {
+        /// <summary>
+        /// Match device serial (attendance_machine_user.serial_number) to employee.serial_number_int.
+        /// </summary>
+        public bool TryGetByDeviceSerial(MySqlConnection connection, string deviceSerial, out HrmsEmployeeInfo employee)
+        {
+            employee = null;
+            if (connection == null || string.IsNullOrWhiteSpace(deviceSerial))
+            {
+                return false;
+            }
+
+            string serial = deviceSerial.Trim();
+
+            // Prefer department name; fall back to department_id if departments table/join is unavailable.
+            const string queryWithDeptName =
+                "SELECT e.id, e.serial_number_int, e.concatenated_name, " +
+                "COALESCE(NULLIF(TRIM(d.name), ''), CAST(e.department_id AS CHAR), '') AS department " +
+                "FROM hrms.employee e " +
+                "LEFT JOIN hrms.departments d ON d.id = e.department_id " +
+                "WHERE CAST(e.serial_number_int AS CHAR) = @DeviceSerial " +
+                "LIMIT 1";
+
+            const string queryBasic =
+                "SELECT e.id, e.serial_number_int, e.concatenated_name, " +
+                "CAST(e.department_id AS CHAR) AS department " +
+                "FROM hrms.employee e " +
+                "WHERE CAST(e.serial_number_int AS CHAR) = @DeviceSerial " +
+                "LIMIT 1";
+
+            try
+            {
+                if (TryReadEmployee(connection, queryWithDeptName, serial, out employee))
+                {
+                    return true;
+                }
+            }
+            catch
+            {
+                // departments table/column may differ; fall back.
+            }
+
+            return TryReadEmployee(connection, queryBasic, serial, out employee);
+        }
+
+        private static bool TryReadEmployee(MySqlConnection connection, string query, string serial, out HrmsEmployeeInfo employee)
+        {
+            employee = null;
+            using (var cmd = new MySqlCommand(query, connection))
+            {
+                cmd.CommandTimeout = 60;
+                cmd.Parameters.AddWithValue("@DeviceSerial", serial);
+                using (var reader = cmd.ExecuteReader())
+                {
+                    if (!reader.Read())
+                    {
+                        return false;
+                    }
+
+                    string id = reader.IsDBNull(0) ? "" : Convert.ToString(reader.GetValue(0))?.Trim();
+                    string serialInt = reader.IsDBNull(1) ? "" : Convert.ToString(reader.GetValue(1))?.Trim();
+                    string name = reader.IsDBNull(2) ? "" : Convert.ToString(reader.GetValue(2))?.Trim();
+                    string department = reader.FieldCount > 3 && !reader.IsDBNull(3)
+                        ? Convert.ToString(reader.GetValue(3))?.Trim()
+                        : "";
+
+                    if (string.IsNullOrWhiteSpace(id))
+                    {
+                        return false;
+                    }
+
+                    employee = new HrmsEmployeeInfo(id, serialInt, name, department);
+                    return true;
+                }
+            }
+        }
+
+        public string ResolveDisplayName(
+            MySqlConnection connection,
+            string deviceSerial,
+            string fallbackName = null)
+        {
+            if (TryGetByDeviceSerial(connection, deviceSerial, out HrmsEmployeeInfo employee)
+                && !string.IsNullOrWhiteSpace(employee.ConcatenatedName))
+            {
+                return employee.ConcatenatedName;
+            }
+
+            if (!string.IsNullOrWhiteSpace(fallbackName))
+            {
+                return fallbackName.Trim();
+            }
+
+            return string.IsNullOrWhiteSpace(deviceSerial) ? "" : deviceSerial.Trim();
+        }
+    }
+}
diff --git a/HrmsEmployeeMappingTests.cs b/HrmsEmployeeMappingTests.cs
new file mode 100644
index 0000000..0635cd0
--- /dev/null
+++ b/HrmsEmployeeMappingTests.cs
@@ -0,0 +1,66 @@
+using System;
+
+namespace HanvonF710XAttendanceService
+{
+    internal static class HrmsEmployeeMappingTests
+    {
+        public static int RunAll()
+        {
+            int failed = 0;
+            failed += Run("photo URL uses employees.id not device serial", TestPhotoUrlUsesEmployeeId);
+            failed += Run("display name prefers concatenated_name", TestDisplayNamePrefersConcatenatedName);
+            failed += Run("display name falls back to device serial", TestDisplayNameFallback);
+            return failed;
+        }
+
+        private static int Run(string name, Func<bool> test)
+        {
+            try
+            {
+                if (!test())
+                {
+                    Console.WriteLine("FAIL: " + name);
+                    return 1;
+                }
+
+                Console.WriteLine("PASS: " + name);
+                return 0;
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine("FAIL: " + name + " err=" + ex.Message);
+                return 1;
+            }
+        }
+
+        private static bool TestPhotoUrlUsesEmployeeId()
+        {
+            // Device serial=15057 maps to employees.id=84321 for photo URL only.
+            string url = HrmsEmployeePhotoClient.BuildPhotoUrl(
+                "https://portal.utopiaindustries.pk/uind/employee-photo/",
+                "84321");
+            return string.Equals(
+                url,
+                "https://portal.utopiaindustries.pk/uind/employee-photo/84321.jpeg",
+                StringComparison.OrdinalIgnoreCase);
+        }
+
+        private static bool TestDisplayNamePrefersConcatenatedName()
+        {
+            var info = new HrmsEmployeeInfo("84321", "15057", "John Smith");
+            return info.EmployeeId == "84321"
+                && info.SerialNumberInt == "15057"
+                && info.ConcatenatedName == "John Smith"
+                && info.EmployeeId != info.SerialNumberInt;
+        }
+
+        private static bool TestDisplayNameFallback()
+        {
+            var info = new HrmsEmployeeInfo("84321", "15057", "");
+            string name = !string.IsNullOrWhiteSpace(info.ConcatenatedName)
+                ? info.ConcatenatedName
+                : "15057";
+            return name == "15057";
+        }
+    }
+}