         public function handleCompletion(command:String, rows:int, oid:int):void {
             if (_columns) {
                 onQueryResult(_columns, _data);
-                _columns = null;
-                _data = null;
             }
             onCompletion(command, rows);
         }

        }

        public function dispose() : void {
            /* do nothing */
        }

    }

            }
            _onQueryResult = onQueryResult;
            _onCompletion = onCompletion;
        }

        public function get columns():Array {
            return _columns;
        }
        
        public function get data():Array {
            return _data;
        }

        public function handleColumns(columns:Array):void {
