public DBNXB() { db = new QLNSEntities(); }
public DBHoaDonBan() { db = new QLNSEntities(); }
public DBNhanVien() { db = new QLNSEntities(); }
public DBSach() { db = new QLNSEntities(); }
public DBHoaDonNhap() { db = new QLNSEntities(); }
public DBTheLoai() { db = new QLNSEntities(); }
public DBTaiKhoan() { db = new QLNSEntities(); }
public DBNhaCC() { db = new QLNSEntities(); }