public KetnoiPhieuChidinhCollection FetchAll()
 {
     KetnoiPhieuChidinhCollection coll = new KetnoiPhieuChidinhCollection();
     Query qry = new Query(KetnoiPhieuChidinh.Schema);
     coll.LoadAndCloseReader(qry.ExecuteReader());
     return coll;
 }
 public KetnoiPhieuChidinhCollection FetchByQuery(Query qry)
 {
     KetnoiPhieuChidinhCollection coll = new KetnoiPhieuChidinhCollection();
     coll.LoadAndCloseReader(qry.ExecuteReader()); 
     return coll;
 }