TEST

[code delphi]
procedure TForm1.cdsUsePrdNoChange(Sender: TField);
begin
SHOWMESSAGE(cds.FieldByName('USEPrdNo').AsString);

fmDM.qyTemp.Close;
fmDM.qyTemp.SQL.Clear;
fmDM.qyTemp.SQL.Text :=
'select Name from PRDT where Prd_No = :Prd_No ';
fmDM.qyTemp.Parameters.ParamByName('Prd_No').Value :=
cds.Fieldbyname('UsePrdNo').Value;
fmDM.qyTemp.Open;
cds.Fieldbyname('PrdNm').AsString :=
fmDM.qyTemp.Fieldbyname('Name').AsString;
end;
[/code]

TEST