public SaveResult Add(PeriodGradeStudentModel entity)
 {
     try
     {
         ObjectParameter param1 = new ObjectParameter("periodGradeStudentId", entity.PeriodGradeStudentId);
         var             result = _context.proc_PeriodGradeStudent_Insert(param1, entity.PeriodGradeGroupModel.PeriodGradeGroupId,
                                                                          entity.StudentModel.StudentId);
         return(new SaveResult
         {
             Id = (int)param1.Value,
             Message = "Student Grade was created.",
             Status = "OK"
         });
     }
     catch (Exception ex)
     {
         return(new SaveResult
         {
             Id = 0,
             Message = "Error on PeriodGradeStudent Add method. " + ex.InnerException != null ? ex.InnerException.Message : ex.Message,
             Status = "ERROR"
         });
     }
 }