public RatingVo insert(RatingVo input)
        {
            using (var db = new MainDb())
            {

                db.ratings.Add(input);
                db.SaveChanges();

                return input;
            }
        }
        public RatingVo update(RatingVo input, Guid? ratingId= null)
        {
            using (var db = new MainDb())
            {

                if (ratingId == null)
                    ratingId = input.ratingId;

                var res = db.ratings.FirstOrDefault(e => e.ratingId == ratingId);

                if (res == null) return null;

                input.created = res.created;
               // input.createdBy = res.createdBy;
                db.Entry(res).CurrentValues.SetValues(input);

                db.SaveChanges();
                return res;

            }
        }