public StudentCourseService(DbService.IStudentEntityService studentService, DbService.ICourseEntityService courseService, DbService.IStudentCourseEntityService studentCourseService)
 {
     _studentService       = studentService;
     _courseService        = courseService;
     _studentCourseService = studentCourseService;
 }
 public CourseService(DbService.ICourseEntityService courseService)
 {
     _courseService = courseService;
 }