public IHttpActionResult GetByID(string id)
 {
     if (parentsService.ExistsID(id) == false)
     {
         return(NotFound());
     }
     return(Ok(parentsService.GetByID(id)));
 }
 public IHttpActionResult PutParentToStudent(string id, string parentId)
 {
     if (studentsService.ExistsID(id) == false || parentsService.ExistsID(parentId) == false)
     {
         return(NotFound());
     }
     if (studentsService.StudentHasParent(id, parentId) == true)
     {
         return(BadRequest("Student allready has this parent in his parent list"));
     }
     return(Ok(studentsService.PutParentToStudent(id, parentId)));
 }