Hi!

I'm using DBISAM 4.25 and Delphi7, C/S mode and internet access

1) I have a DBGrid showing some records, and some DBEdits, DBDateEdits and a
DBLookUpCombobox to show current record aditional data.
2) DBLookUpComboBox.ListSource is another remote (and opened) table.
3) When I scroll or click another record in the DBGrid (move from one record
to another), it takes about 5 seconds to set the cursor on the new record.

If I deactivate the DBLookUpComboBox, the scroll is instantaneous.
It seems that, when changing the current record, it makes a 'locate' to
second table.

Is it possible to increase the speed? Maybe using a independent Query for
lookup table? Any way to deactivate lookup locate?

Thanks!

If I deactivate the DBLookUpComboBox, the scroll is instantaneous.
It seems that, when changing the current record, it makes a 'locate' to
second table.

Luis,

I have been banging on this issue for 2 weeks now. (BDS 2006)

The problem comes from the DBLookUpComboBox.

Suppose you have a table (limited for explanation) that goes like this

Fields([(IsJob, ftBoolean), (JobKey, ftString[6]), (CustJobKey, ftString[6]), (Other data
...)])

IxCust : Index(IsJob, JobKey) -> SetRange IsJob=False in DBLookUpComboBox.ListSource.DataSet
IxJob  : Index(CustJobKey, IsJob, JobKey) -> No Range for a matching DBGrid

You cannot specify multiple KeyFields for the DBLookUpComboBox.ListSource.KeyField so
you will have indicated DataField=CustJobKey and KeyField=JobKey. What happens is
that DBLookUpComboBox (DBCtrls.TDDBLookupControl for that matter) tries to match
JobKey with the first field of Index IxCust which is of type ftBoolean and is a mismatch
of FieldType
SO Locates (in DBCtrls.TDBLookupControl.LocateKey and
DBCtrls.TDBLookupControl.ProcessSearchKey)
by default will scan all the rows of the table to find a corresponding CustJobKey. If the
table has something
like more than a hundred records you'll fill it badly.

In fact DBLookUpComboBox is generally very ill. It will make at least to or three locates
(even simple ones
with a non composite Key) doesn't clean up Key when they have been processed etc... etc
... Very Ill ...
and has been so since Delphi 3 but I had not felt it because my tables didn't need
multi-part keys.

IF SOMONE KNOWS OF A SIMPLE CONTROL THAT DOES THE JOB,  MENTION IT PLEASE. Of
course not one of these things that load all rows in memory, for obvious reasons.

Bruno

Bruno Krayenbuhl <b.kray@_bluewin> wrote in
news:E833B77A-9AFC-43F6-B16C-6F8B4B1E20DE@news.elevatesoft.com:

> If I deactivate the DBLookUpComboBox, the scroll is instantaneous.
> It seems that, when changing the current record, it makes a 'locate'
> to second table.
>
> IF SOMONE KNOWS OF A SIMPLE CONTROL THAT DOES THE JOB,  MENTION IT
> PLEASE. Of course not one of these things that load all rows in
> memory, for obvious reasons.
>

If in the main table's BeforeScroll event you deactivate the
DBLookUpComboBox and reset-then-set a timer that reactivates it after a few
hundred milliseconds, then if you scroll several times it will stay
deactivated all the time and refill its list only once you stop scrolling.

--
Chris
(XP-Pro + Delphi 7 Architect + DBISAM 4.25 build 4 + EDB 1.02 build 1)

Luis,

<< If I deactivate the DBLookUpComboBox, the scroll is instantaneous. It
seems that, when changing the current record, it makes a 'locate' to second
table.

Is it possible to increase the speed? Maybe using a independent Query for
lookup table? Any way to deactivate lookup locate? >>

The best way to work around performance issues like this is to set the
lookup field's LookupCache property to True.

--
Tim Young
Elevate Software
www.elevatesoft.com

Chris,

...
If in the main table's BeforeScroll event you deactivate the
DBLookUpComboBox and reset-then-set a timer that reactivates it after a few
hundred milliseconds, then if you scroll several times it will stay
deactivated all the time and refill its list only once you stop scrolling.
...

What I meant is that Borland's code is flawed in this particular control.
One might imagine fixing DBCtrls unit but if you do so, you wont be able to rebuild, for
example, DBSys because there will be a Version mismatch from QRStandard that is delivered
with Delphi and is used in DBSys.

To further elaborate just examine the private variable FLookupMode that is declared once
in TDBLookupControl and once in TDBLookupComboBox. I can tell you that in
TDBLookupComboBox.KeyValueChanged it is always false so there will systematically a new
LocateKey etc...

Regards, Bruno

with    assssssssssssssssssssssss

Chris,

Sorry for the last line of my post, it was a typing error on my part.

Regards, Bruno