ibec_GetGlobalVar('IBE$DECIMAL_SEPARATOR', '-')

Application.UpdateFormatSettings := False;

procedure TApplication.WndProc(var Message: TMessage);
............
begin
    ..............
    CheckIniChange(Message);
    ..........
end;
..................
function TApplication.CheckIniChange(var Message: TMessage): Boolean;
begin
  Result := False;
  if (Cardinal(Message.Msg) = RM_TaskbarCreated) or
     (Cardinal(Message.Msg) = WM_WININICHANGE) then
  begin
    if UpdateFormatSettings then
    begin
      SetThreadLocale(LOCALE_USER_DEFAULT);
      GetFormatSettings;
    end;
    if UpdateMetricSettings then
      Screen.GetMetricSettings;
    ................
  end;
end;

procedure GetFormatSettings;
begin
  InitSysLocale;
  if SysLocale.FarEast then
    GetEraNamesAndYearOffsets;
  FormatSettings := TFormatSettings.Create('');
end;

SELECT CAST(999999999999 AS NUMERIC(18, 6)) FROM RDB$DATABASE;

                 CAST
=====================
  999999999999.000000

CREATE OR ALTER VIEW VW_VEW1(
    VAL)
AS
SELECT
  CAST(cfg.IDENT AS NUMERIC(18, 6))
FROM
  mytable cgf
;

CREATE OR ALTER TRIGGER TR_VW_VIEW1_BU0 FOR VW_VIEW1
ACTIVE BEFORE UPDATE POSITION 0
AS
BEGIN
  UPDATE mytable cfg SET
    cfg.IDENT = NEW.VAL
  WHERE
    cfg.IDENT = OLD.VAL
END