public void PutStudent(int id, Student stud)
 {
     stud.Id = id;
     dbCtxt.Students.Attach(stud);
     dbCtxt.Entry(stud).State = System.Data.EntityState.Modified;
     dbCtxt.SaveChanges();
 }
        public HttpResponseMessage PostStudent(Student stud)
        {
            if (!ModelState.IsValid)
            {
                throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.BadRequest, this.ModelState));
            }

            dbCtxt.Students.Add(stud);
            int records = dbCtxt.SaveChanges();

            var response = Request.CreateResponse(HttpStatusCode.Created, stud);
            response.Headers.Location = new Uri(Url.Link(ODataRouteNames.GetById, new { Controller = "Students", Id = stud.Id }));
            return response;
        }