BorlandTalk.com

bcb · Guest

Hello

Have you tried using EmptyTable? it will work much faster than iterating.
Also whenever looping through records in a Table that has data aware
controls connected to it first call
Table.DisableControls; loop through the records and last call
Table.EnableControls.

bcb · Guest

sorry that would be

TableName->DisableControls();
and
TableName->EnableControls();

;-)

Dwayne · Guest

Hello BCB

BCB>>Have you tried using EmptyTable? it will work much faster than
iterating. Also whenever looping through records in a Table that has data
aware controls connected to it first call Table.DisableControls; loop
through the records and last call Table.EnableControls.<<

His problem was not necessarily emptying the table, but "Shrinking"
the table to its actual size after deleting. Otherwise known as "Packing"
for those who do Dbase. I do not know of a command that will take a table
and "Pack" the table, after deleting all the records. Do you know of a way
to do such a job? I would be interested in knowing it. Either that, you
must have exclusive rights to the table.

Dwayne

bcb · Guest

Hi Dwayne,

You should try EmptyTable, If I remember correctly it does more than just
delete all records inside a table. I don't have the VCL source on the PC I'm
using at the moment to check what exactly happens behind the scenes but it
will revert the table file size back to as if it was just created.

bcb · Guest

p.s.

when using EmptyTable , I make sure the table isn't active during design
time, open the table at runtime. Then,

Table1->Close(); //active=false;
Table1->EmptyTable();
Table1->Open();

Works just fine.

bcb · Guest

Yes,Your suggestion would be the best if one would need to keep some records
and not a full empty, delete the records, create a new table and batchmove
over the records from the old into the new, delete the old, rename the new.
But those empty slots are relocated with data if new records are added, so
if it's constant loop of delete and add the same number or similar number of
records, then file size shouldn't be a problem these days.

Dwayne · Guest

Hello BCB,

BCB>>You should try EmptyTable, If I remember correctly it does more than
just delete all records inside a table. I don't have the VCL source on the
PC I'm using at the moment to check what exactly happens behind the scenes
but it will revert the table file size back to as if it was just created.<<

The gentleman could not use Empty Table, because there are active
records within that table. His comment was that there are sometimes records
at the end of the file that he did not want to delete.

One of the problems with Empty Table, is the Index is not sized
correctly. Thus, I stopped using EmptyTable, and just deleted the table
and index, following it by a CreateTable. Thus I had extreme speed to get
the job done. Finding a way to Pack a DBase table is a problem though.

Dwayne

Antonio Felix · Guest

Hi Dwayne,

See
http://info.borland.com/devsupport/bde/bdeapiex/dbidorestructure.html

for a sample on how to pack a Dbase Table. The code is
Delphi but it should be converted easily.
Meanwhile i'll try to locate a Bcb function that i've used in
the past to Pack Dbase Files...It was some time ago...

Antonio Felix · Guest

Hi Dwayne,

In order to use the Bde Api functions you must include the
bde.hpp file.

Check the Bde Online reference help file and look at
DbiPackTable

HTH
Antonio