Filtering two IBTable and insert or edit IBTable

[danten]

I need to recursively insert data from one table to another table by index (USERID =>> ID) common to both tables.
My function does not complete the operation.

Delphi-Quellcode:

function TFrm_main.Add_UserName:boolean;
var
  i:Integer;
begin
  ds_users.DataSet.First;
  for I := 0 to ds_users.DataSet.RecordCount -1 do
  begin
    Application.ProcessMessages;
    ds_attendant.DataSet.Filtered := False;
    ds_attendant.DataSet.Filter := 'USERID = '+QuotedStr(ds_users.DataSet.FieldByName('ID').Value);
    ds_attendant.DataSet.Filtered := True;
    Application.ProcessMessages;
  while not  ds_attendant.DataSet.Eof do
  begin
  if (ds_attendant.DataSet.RecordCount > 0) then
  begin
    Application.ProcessMessages;
    ds_attendant.DataSet.Edit;
    ds_attendant.DataSet.FieldByName('NAME').Value := ds_users.DataSet.FieldByName('USERNAME').Value;
    ds_attendant.DataSet.Post;
    Application.ProcessMessages;
  end else
  begin
    ds_users.DataSet.Next;;
  end;
  end;
    ds_users.DataSet.Next;
  end;
  Result := True;
  ds_attendant.DataSet.Filtered := False;
end;