public static List<Discount> GetAllData()
        {
            var dal = new DiscountDAL();
            var collection = new List<Discount>();

            foreach (DataRow row in dal.GetAllData().Rows)
            {
                var instance = new Discount();
                instance.Bind(row);

                collection.Add(instance);
            }

            return collection;
        }
        public static bool InsertNewDiscount(Discount instance)
        {
            var dal = new DiscountDAL();

            return dal.InsertNewDiscount(instance);
        }