public KetnoiDichvuCollection FetchAll()
 {
     KetnoiDichvuCollection coll = new KetnoiDichvuCollection();
     Query qry = new Query(KetnoiDichvu.Schema);
     coll.LoadAndCloseReader(qry.ExecuteReader());
     return coll;
 }
 public KetnoiDichvuCollection FetchByQuery(Query qry)
 {
     KetnoiDichvuCollection coll = new KetnoiDichvuCollection();
     coll.LoadAndCloseReader(qry.ExecuteReader()); 
     return coll;
 }
 public KetnoiDichvuCollection FetchByID(object Id)
 {
     KetnoiDichvuCollection coll = new KetnoiDichvuCollection().Where("ID", Id).Load();
     return coll;
 }