Alex
At the very least you should
SQL.BeginUpdate
SQL.Add ('select');
SQL.Add ('from');
SQL.Add ('customers');
SQL.EndUpdate
This stops the TStrings.Onchange event (which is used to compile the SQL)
changing on each line
On an unrelated issue I was testing the performance of a Client/stais
Dataset and got these results (42,000 records)
To Open and download records 17 sec - To Scroll true (using next) 221 sec!
(on a client dataset!)
Then I wrapped it with DisableControls/EnableControls = 3.1 seconds -
strange thing is it is an unbound dataset - no
controls to disable but makes a huge difference in performance
with TestDataSet do
Try
Open
// 17 seconds for 42,000 records
DisableControls
first
while not EOF do Next
finally
// 221 sec without Dis/En 3.1 with
EnableControls
end
Regards
----- Original Message -----
From: Alex Kouznetsov <[EMAIL PROTECTED]>
To: Multiple recipients of list delphi <[EMAIL PROTECTED]>
Sent: Tuesday, 19 September 2000 23:03
Subject: [DUG]: Wow ! Every TADOQuery.SQL changing at run-time causes
separate sp_prepare call
> Am I crazy ? Am I doing something wrong ?
>
> I have just accidentally found, that whenever SQL property of TADOQuery
> changes, there is a separate stored procedure call sent to SQL server.
>
> It can be seen via SQL Server Profiler.
>
> Whenever either SQL.Add is used or SQL.Text is changed in any way, there
is
> a call looking like "sp_prepare @p1 output etc.."
>
> If I do
>
> SQL.Add ('select');
> SQL.Add ('from');
> SQL.Add ('customers');
>
> then there will be 3 calls to sp_prepare !!!
>
> I generate long sql statements in loops and get tonns of this sent to the
> server.
>
> I found that these calls do not occur if ParamCheck property of ADOQuery
is
> set to FALSE ! But then ':' style parameters do not get recognized by ADO
> and they all have to be somehow manually created.
>
> Does anyone have any suggestions,comments,ideas on this ?
>
> Regards
> Alex
>
>
>
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