循环数据集字段赋默认值

              for i:=0 to FieldCount-1 do
                if Fields[i].IsNull then
                  case Fields[i].DataType of
                    ftInteger          : Fields[i].AsInteger:=0;
                    ftFloat, ftCurrency: Fields[i].AsCurrency:=0.00;
                    ftString           : Fields[i].AsString:='';
                    ftDateTime         : ;
                  end;