//protected DoctorData doctorData; public StudentDoctorAddEdit(Student student, DBCommand dbc) : base(student, dbc) { _database = new DoctorData(_dbc); foreach (Doctor doctor in student.Doctors) { bool personExists = _database.PersonExists(doctor.PersonId, student.PersonId); if (!personExists) { _database.Allocate(doctor, student.PersonId); } } foreach (object obj in student.RemovedObjects) { if (obj is Doctor) { _database.Remove((Doctor)obj, student.PersonId); } } }