public DAL_GiaoVien() { cnn = new KetNoiDuLieu(); }
public DAL_User() { cnn = new KetNoiDuLieu(); }
public DAL_MonHoc() { cnn = new KetNoiDuLieu(); }
public DAL_Lop() { cnn = new KetNoiDuLieu(); }
public DAL_SinhVien() { cnn = new KetNoiDuLieu(); }
public DAL_LoaiDiem() { cnn = new KetNoiDuLieu(); }