Auto Generate Sequence in ClientDataSet

    FLastID: Integer;

   ........

procedure TForm1.ClientDataSet1BeforeInsert(DataSet: TDataSet);
var
 b: TBookMark;
begin
 with DataSet do
  begin
    DisableControls;
    b := GetBookmark;
    try
      Last;
      FLastID := DataSet.FindField('id').AsInteger;
      GotoBookmark(b);
    finally
      FreeBookmark(b);
      EnableControls;
    end;
  end;
end;

procedure TForm1.ClientDataSet1AfterInsert(DataSet: TDataSet);
begin
 DataSet.FindField('id').AsInteger := FLastID + 1;
end;