Reorder rows in TClientDataSet - delphi

Question

In order to show my data in some order, I have ORDER column. So I can move up and down rows. That is already working, I just swap ORDER number for the affected rows. My problem is, when I delete a row, I need to reorder all other rows. To show the rows in the proper order I use the .IndexFieldNames := 'ORDER', but when I iterate through all rows and assign the new ORDER number, with active index its pretty slow. When I remove the .IndexFieldNames := '', then the rows are not in the correct order anymore, and the new order is wrong.
Here is my code:
class procedure TDataModuleEx.ReOrderColumn(const aDataSet: TClientDataSet;
const aFieldName: string; aResetClone: Boolean);
var
clone: TClientDataSet;
newOrderNo: Integer;
begin
newOrderNo := 0;
clone := TClientDataSet.Create(nil);
try
clone.CloneCursor(aDataSet, aResetClone);
clone.IndexFieldNames := aFieldName;
clone.IndexFieldNames := ''; //Indexed Edit is too slow
clone.First;
while not clone.eof do
begin
Inc(newOrderNo);
clone.Edit;
clone.FieldByName(aFieldName).AsInteger := newOrderNo;
clone.Post;
clone.Next;
end;
finally
clone.Free;
end;
end;
How can I reorder my rows after one is deleted efficiently?

Answer 1

I made some testing on a table with 10 000 records. Procedure ReOrderColumn made renumbering for about 3 seconds. ClientDataSet. ApplyUpdate took about 30 seconds.
Total about 33 seconds.
I wrote stored procedure in Firebird database which made renumbering for about 3 seconds.
SET TERM ^ ;
create or alter procedure REORDER
as
declare variable ID integer;
declare variable I integer;
BEGIN
i = 0;
FOR
select new_table.id
from new_table
order by FORDER
INTO :ID
as cursor tcur
DO
BEGIN
i = :i + 1;
update new_table t set t.forder = :i
where current of tcur;
END
END^
SET TERM ; ^
From Delphi
procedure Reorder;
begin
//Apply changes to server
dm1.ClientDataSet1.ApplyUpdates(0);
//execute stored procedure
dm1.spReorder.ExecProc; <--- ABOUT 3 SEC FOR 10 000 records
//Refresh dataset
dm1.ClientDataSet1.Close;
dm1.ClientDataSet1.Open;
end;