public IHttpActionResult Create(ArtistModel item)
        {
            if (!this.ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }

            var newItem = new Artist()
            {
                Name = item.Name,
                Country = item.Country,
                DateOfBirth = item.DateOfBirth,
            };

            this.data.Artists.Add(newItem);
            this.data.Artists.SaveChanges();

            item.Id = newItem.Id;

            return this.Ok(item);
        }
        public IHttpActionResult Update(int id, ArtistModel item)
        {
            if (!this.ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }

            var existingItem = this.data.Artists.Find(id);

            if (existingItem == null)
            {
                return this.BadRequest("Invalid Artist");
            }

            // Check if some of the fields in the new data are not null
            if (!string.IsNullOrEmpty(item.Name))
            {
                existingItem.Name = item.Name;
            }

            if (!string.IsNullOrEmpty(item.Country))
            {
                existingItem.Country = item.Country;
            }

            if (item.DateOfBirth != null)
            {
                existingItem.DateOfBirth = item.DateOfBirth;
            }

            this.data.Artists.SaveChanges();

            item.Id = existingItem.Id;

            return this.Ok(item);
        }