public bool Delete(ScheduleExam exam)
        {
            db.ScheduleExams.Remove(exam);
            bool isDeleted = db.SaveChanges() > 0;

            return(isDeleted);
        }
        public bool Add(ScheduleExam exam)
        {
            db.ScheduleExams.Add(exam);
            bool isAdded = db.SaveChanges() > 0;

            return(isAdded);
        }
        public bool Update(ScheduleExam exam)
        {
            db.ScheduleExams.Attach(exam);
            db.Entry(exam).State = EntityState.Modified;
            bool isUpdated = db.SaveChanges() > 0;

            return(isUpdated);
        }