public TrainingProvidersController(CatalogDbContext db)
 {
    _db = db;
 }
 protected override void Dispose(bool disposing)
 {
    if (disposing && _db != null)
    {
       _db.Dispose();
       _db = null;
    }
    base.Dispose(disposing);
 }
 public CoursesWithoutSpecializationsController(CatalogDbContext db)
 {
    _db = db;
 }