(B) Update visit-related entities, add FKs to visit

Clinics.Backend/Domain/Entities/Visits/Relations/VisitMedicalImages/VisitMedicalImage.cs

 using Domain.Entities.Medicals.MedicalImages;
+using Domain.Exceptions.InvalidValue;
 using Domain.Primitives;
 
 namespace Domain.Entities.Visits.Relations.VisitMedicalImages;
 
 // TODO: Convert result to a value object
-public sealed class VisitMedicalImage(int id) : Entity(id)
+public sealed class VisitMedicalImage : Entity
 {
+    #region Private ctor
+
+    private VisitMedicalImage(int id) : base(id) { }
+
+    private VisitMedicalImage(int id, int visitId, int medicalImageId) : base(id)
+    {
+        VisitId = visitId;
+        MedicalImageId = medicalImageId;
+
+        Result = null;
+    }
+
+    #endregion
+
     #region Properties
 
     #region Visit
@@ -29,4 +44,28 @@ public sealed class VisitMedicalImage(int id) : Entity(id)
     #endregion
 
     #endregion
+
+    #region Methods
+
+    #region Static factory
+    public static VisitMedicalImage Create(int visitId, int medicalImageId)
+    {
+        if (visitId <= 0 || medicalImageId <= 0)
+            throw new InvalidValuesDomainException<VisitMedicalImage>();
+
+        return new VisitMedicalImage(0, visitId, medicalImageId);
+    }
+    #endregion
+
+    #region Add result
+    public void AddResult(string result)
+    {
+        if (result is null)
+            throw new InvalidValuesDomainException<VisitMedicalImage>();
+
+        Result = result;
+    }
+    #endregion
+
+    #endregion
 }

Clinics.Backend/Domain/Entities/Visits/Relations/VisitMedicalTests/VisitMedicalTest.cs

 using Domain.Entities.Medicals.MedicalTests;
+using Domain.Entities.Visits.Relations.VisitMedicalImages;
+using Domain.Exceptions.InvalidValue;
 using Domain.Primitives;
 
 namespace Domain.Entities.Visits.Relations.VisitMedicalTests;
 
 // TODO: Convert result to a value object
-public sealed class VisitMedicalTest(int id) : Entity(id)
+public sealed class VisitMedicalTest : Entity
 {
+    #region Private ctor
+
+    private VisitMedicalTest(int id) : base(id) { }
+
+    private VisitMedicalTest(int id, int visitId, int medicalTestId) : base(id)
+    {
+        VisitId = visitId;
+        MedicalTestId = medicalTestId;
+
+        Result = null;
+    }
+
+    #endregion
+
     #region Properties
 
     #region Visit
@@ -29,4 +45,28 @@ public sealed class VisitMedicalTest(int id) : Entity(id)
     #endregion
 
     #endregion
+
+    #region Methods
+
+    #region Static factory
+    public static VisitMedicalTest Create(int visitId, int medicalTestId)
+    {
+        if (visitId <= 0 || medicalTestId <= 0)
+            throw new InvalidValuesDomainException<VisitMedicalTest>();
+
+        return new VisitMedicalTest(0, visitId, medicalTestId);
+    }
+    #endregion
+
+    #region Add result
+    public void AddResult(string result)
+    {
+        if (result is null)
+            throw new InvalidValuesDomainException<VisitMedicalTest>();
+
+        Result = result;
+    }
+    #endregion
+
+    #endregion
 }

Clinics.Backend/Domain/Entities/Visits/Relations/VisitMedicines/VisitMedicine.cs

 using Domain.Entities.Medicals.Medicines;
+using Domain.Exceptions.InvalidValue;
 using Domain.Primitives;
 
 namespace Domain.Entities.Visits.Relations.VisitMedicines;
 
-public sealed class VisitMedicine(int id) : Entity(id)
+public sealed class VisitMedicine : Entity
 {
+
+    #region Private ctor
+    private VisitMedicine(int id) : base(id) { }
+
+    private VisitMedicine(int id, int visitId, int medicineId, int number) : base(id)
+    {
+        VisitId = visitId;
+        MedicineId = medicineId;
+
+        Number = number;
+    }
+    #endregion
+
     #region Properties
 
     #region Visit
@@ -28,4 +42,18 @@ public sealed class VisitMedicine(int id) : Entity(id)
     #endregion
 
     #endregion
+
+    #region Methods
+
+    #region Static factory
+    public static VisitMedicine Create(int visitId, int medicineId, int number)
+    {
+        if (visitId <= 0 || medicineId <= 0 || number <= 0)
+            throw new InvalidValuesDomainException<VisitMedicine>();
+
+        return new VisitMedicine(0, visitId, medicineId, number);
+    }
+    #endregion
+
+    #endregion
 }

Clinics.Backend/Domain/Entities/Visits/Visit.cs

 using Domain.Entities.Medicals.Hospitals;
+using Domain.Entities.Medicals.MedicalImages;
+using Domain.Entities.Medicals.MedicalTests;
+using Domain.Entities.Medicals.Medicines;
 using Domain.Entities.People.Doctors;
 using Domain.Entities.People.Patients;
 using Domain.Entities.Visits.Relations.VisitMedicalImages;
 using Domain.Entities.Visits.Relations.VisitMedicalTests;
 using Domain.Entities.Visits.Relations.VisitMedicines;
+using Domain.Exceptions.InvalidValue;
 using Domain.Primitives;
 
 namespace Domain.Entities.Visits;
 
-public sealed class Visit(int id) : Entity(id)
+public sealed class Visit : Entity
 {
+    #region Private ctor
+
+    private Visit(int id) : base(id) { }
+
+    private Visit(int id, int patientId, int doctorId, DateOnly date, string diagnosis) : base(id)
+    {
+        PatientId = patientId;
+        DoctorId = doctorId;
+        Date = date;
+        Diagnosis = diagnosis;
+
+        HospitalId = null;
+    }
+
+    #endregion
+
     #region Properties
 
+    #region Patient
+
+    public int PatientId { get; set; }
     public Patient Patient { get; set; } = null!;
 
+    #endregion
+
+    #region Doctor
+
+    public int DoctorId { get; set; }
     public Doctor Doctor { get; set; } = null!;
 
-    public Hospital? Hospital { get; set; }
+    #endregion
+
+    #region Additional
 
     public DateOnly Date { get; set; }
 
     public string Diagnosis { get; set; } = null!;
 
+    #region Hospital
+
+    public int? HospitalId { get; set; }
+    public Hospital? Hospital { get; set; }
+
+    #endregion
+
+    #endregion
+
     #region Navigations
 
     public ICollection<VisitMedicalImage> MedicalImages { get; set; } = [];
@@ -31,4 +70,84 @@ public sealed class Visit(int id) : Entity(id)
     #endregion
 
     #endregion
+
+    #region Methods
+
+    #region Static factory
+    public static Visit Create(int patientId, int doctorId,  DateOnly date, string diagnosis)
+    {
+        if (patientId <= 0 || doctorId <= 0 || diagnosis is null)
+            throw new InvalidValuesDomainException<Visit>();
+        
+        return new Visit(0, patientId, doctorId, date, diagnosis);
+    }
+    #endregion
+
+    #region Add medical image
+    public void AddMedicalImage(MedicalImage medicalImage)
+    {
+        VisitMedicalImage entry;
+        try
+        {
+            entry = VisitMedicalImage.Create(Id, medicalImage.Id);
+        }
+        catch
+        {
+            throw;
+        }
+
+        if (MedicalImages is null)
+            MedicalImages = [];
+
+        MedicalImages.Add(entry);
+    }
+    #endregion
+
+    #region Add medical test
+    public void AddMedicalTest(MedicalTest medicalTest)
+    {
+        VisitMedicalTest entry;
+        try
+        {
+            entry = VisitMedicalTest.Create(Id, medicalTest.Id);
+        }
+        catch
+        {
+            throw;
+        }
+        if (MedicalTests is null)
+            MedicalTests = [];
+        MedicalTests.Add(entry);
+    }
+    #endregion
+
+    #region Add medicine
+    public void AddMedicine (Medicine medicine, int number)
+    {
+        VisitMedicine entry;
+        try
+        {
+            entry = VisitMedicine.Create(Id, medicine.Id, number);
+        }
+        catch
+        {
+            throw;
+        }
+        if (Medicines is null)
+            Medicines = [];
+        Medicines.Add(entry);
+    }
+    #endregion
+
+    #region Add hospital
+    public void AddHospital(Hospital hospital)
+    {
+        if (hospital is null)
+            throw new InvalidValuesDomainException<Visit>();
+        Hospital = hospital;
+        HospitalId = hospital.Id;
+    }
+    #endregion
+
+    #endregion
 }

Clinics.Backend/Persistence/Configurations/People/Patients/PatientConfiguration.cs

@@ -23,6 +23,7 @@ internal class PatientConfiguration : IEntityTypeConfiguration<Patient>
 
         builder.HasMany(patient => patient.Visits)
             .WithOne(visit => visit.Patient)
+            .HasForeignKey(visit => visit.PatientId)
             .OnDelete(DeleteBehavior.NoAction);
     }
 }
\ No newline at end of file

Clinics.Backend/Persistence/Configurations/Visits/VisitConfiguration.cs

@@ -14,10 +14,12 @@ internal class VisitConfiguration : IEntityTypeConfiguration<Visit>
 
         builder.HasOne(visit => visit.Doctor)
             .WithMany()
+            .HasForeignKey(visit => visit.DoctorId)
             .OnDelete(DeleteBehavior.NoAction);
 
         builder.HasOne(visit => visit.Hospital)
             .WithMany()
+            .HasForeignKey(visit => visit.HospitalId)
             .OnDelete(DeleteBehavior.NoAction);
     }
 }
\ No newline at end of file