public static void NewEwithS(int idExpertise, SubjectDto subjectDto)
 {
     using (placementDepartmentDBEntities placementDepartmentDB = new placementDepartmentDBEntities())
     {
         Expertise expertise = placementDepartmentDB.Expertise.Find(idExpertise);
         Subject   subject   = placementDepartmentDB.Subject.Find(subjectDto.Id);
         if (!expertise.Subject.Contains(subject))
         {
             expertise.Subject.Add(subject);
             placementDepartmentDB.SaveChanges();
         }
         else
         {
             throw new Exception("Duplicate");
         }
     }
 }
 public static void DeleteExpertise(int id)
 {
     using (placementDepartmentDBEntities placementDepartmentDB = new placementDepartmentDBEntities())
     {
         try
         {
             Expertise expertise = placementDepartmentDB.Expertise.Find(id);
             placementDepartmentDB.Expertise.Remove(expertise);
             placementDepartmentDB.SaveChanges();
         }
         catch (DbUpdateException ex)
         {
             var sqlException = ex.GetBaseException() as SqlException;
             if (sqlException != null)
             {
                 if (sqlException.Number == 547)
                 {
                     throw new DbUpdateException("547");
                 }
             }
         }
     }
 }