begin
   ibcSourceList.SQL.Clear;
   ibcSourceList.SQL.Add('select rdb$relation_name from rdb$relations');
   ibcSourceList.SQL.Add('where rdb$system_flag = 0');
   ibcSourceList.SQL.Add('order by rdb$relation_name');
   ibcSourceList.Open;
   while not ibcSourceList.Eof do
   begin
     lbSourceTables.Items.Add(ibcSourceList.Fields[0].AsString);
     ibcSourceList.Next;
   end;
   ibcSourceList.Close;
 end;