(B) Update WaitingListRecord entity

Clinics.Backend/Domain/Entities/WaitingList/WaitingListRecord.cs

 using Domain.Entities.People.Doctors;
 using Domain.Entities.People.Patients;
+using Domain.Exceptions.InvalidValue;
 using Domain.Primitives;
 
 namespace Domain.Entities.WaitingList;
 
-public sealed class WaitingListRecord(int id) : Entity(id)
+public sealed class WaitingListRecord : Entity
 {
+    #region Private ctor
+    private WaitingListRecord(int id) : base(id) { }
+
+    private WaitingListRecord(int id, int patientId) : base(id)
+    {
+        PatientId = patientId;
+        IsServed = false;
+    }
+
+    #endregion
+
     #region Properties
 
     #region Patient
@@ -29,4 +41,28 @@ public sealed class WaitingListRecord(int id) : Entity(id)
     #endregion
 
     #endregion
+
+    #region Methods
+
+    #region Static factory
+
+    public static WaitingListRecord Create(int patientId)
+    {
+        if (patientId <= 0)
+            throw new InvalidValuesDomainException<WaitingListRecord>();
+        return new WaitingListRecord(0, patientId);
+    }
+
+    #endregion
+
+    #region Link to doctor
+    public void LinkToDoctor(int doctorId)
+    {
+        if (doctorId <= 0)
+            throw new InvalidValuesDomainException<WaitingListRecord>();
+        DoctorId = doctorId;
+    }
+    #endregion
+
+    #endregion
 }