Hi Bram,

you do a bit unneccessary and confusing work in your example. There's no
need to Unprepare your IB_Query2, just make sure it is closed. Repreparing
is only required when you change the SQL statement, not when you change the
value of a parameter. And ParamByName automatically prepares a statement if
neccessary (which has to be done to make the parameters available), so your
call to IB_Query2.Prepare is redundant (you may include "if not
IB_Query2.Prepared then IB_Query.Prepare" for readability before you set
the parameter). I suggest you change your code to

procedure TMDIChild.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
if IB_Query2.Active then
IB_Query2.Close;
{ if not IB_Query2.Prepared then
IB_Query.Prepare;} //This "if" is optional
IB_Query2.ParamByName('PR1').Asstring:=edit1.text+Key;
IB_Query2.First;
end;

When it comes to incremental searching, I think it is possible to set a
parameter which specifies how many characters must be typed before the
incremental search begins. It would surprise me if starting the incremental
search after the first character would be a good idea when the table
contains 500 000 street names. The odds for being on the right record
immediately is rather low, and do many streets in the Netherlands have a
name of only one character? (if so, I think it would only be to hit enter
after the character).

Good luck,
Set

At 16:48 17.01.2001 +0100, you wrote:

>Thanks for your answer. Iam aware about the large result- problem but I
>always tend to disagree when I hear: not possible....
>
>My target clients are all 100MB so I do optimize for that. When doing my
>first test with the large database I was amazed how quick interbase/ibo gave
>a instant result back when only quering for specific streets. So Interbase
>has no speed problem to return anything specific from 500.000 rows. That
>leads me to believe there should by a possibilty to do incrematal search:
>
>When doing an incremental search the first thing that's important wether the
>keyed combination gives an result anyway. I tried to find a solution by
>searching first for a result with only one row returning. I found this by
>doing a query.first.
>
>I created an simple example and ib_query/editbox/ib_grid/ib_datasource with
>the following query:
>
>Select * from zipcode where street starts with :PR1
>
>when pressing an key inside the editbox the following is happening:
>
>procedure TMDIChild.Edit1KeyPress(Sender: TObject; var Key: Char);
>begin
>
> with IB_Query2 do begin
> if IB_Query2.Prepared then
> IB_Query2.Unprepare;
> IB_Query2.ParamByName('PR1').Asstring:=edit1.text+Key;
> IB_Query2.Prepare;
> IB_Query2.First;
> end;
>end;
>
>I connected the ib_grid to the datasource. It's refreshing automaticly and
>showing/filling only the rows visible inside the grid.
>
>The results are great. The only data transfered are the rows inside the
>grid. No more rowfetch at all. It doesn't matter wich letters I presse I get
>instant result from the 500.000 streets (and yes there are a lot of streets
>before the B).
>
>Am I totally wrong with this approach? Would this lead to unaccaptable
>performance at the server for other query's. I think there really small...
>only repeated a lot of times.
>
>
>Bram van der Voet
>
>
>
>
>