public IHttpActionResult DeleteSubjectFromTeacher(string id, int subjectId) { if (teachersService.ExistsID(id) == false || subjectsService.ExistsID(subjectId) == false) { return(NotFound()); } if (teachersService.TeacherHasSubject(id, subjectId) == false) { return(BadRequest("Teacher does not have refered subject in his subject list")); } return(Ok(teachersService.DeleteSubjectFromTeacher(id, subjectId))); }