(Solved)DBF Packtable
lazarus / 16-Databases

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MVD · 2017-09-21 10:07

Hi,
I have a program that is working very well, I have only one problem.
I am working with DBASE VII tables ( I know, is old  and there are
more modern databases but I am confortable with it because I was
programming in Delphi6 long time ago) and the table is open Shared.(So
we can use the program with 2 or more users). I have a menu item to
clean up the database. Regenerating indexes is no problem but when I
try to pack the table with ".packtable" I have a problem. To pack the
table I have to set the exclusive propertie, If a set:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i [color=red]
 hoofdvenster.Dbf1.Exclusive:=true;   hoofdvenster.Dbf1.PackTable;
[/color]I got the message : "Exclusive access is required for this
operation"
If I set:
   Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
[color=red]hoofdvenster.Dbf1.close; 
 hoofdvenster.Dbf1.Exclusive:=true;   hoofdvenster.Dbf1.open:=true  ; 
 hoofdvenster.Dbf1.PackTable; [/color]I got the message : "unable to
open file "C:\x.dbf"
??????

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fred · 2017-09-21 11:35

Perhaps the other has the database open so it can't be opened in
Exclusive mode?

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MVD · 2017-09-21 12:58

I am sure that de DBF is not used, so normal "exclusive" must be OK.
It is like I can not override the options I see in the object
inspector.
To work I have to set the database propertie active to false and the
exclusive propertie to true ( if I let the active propertie to
true I get the compiler error "unable to open file "x.dbf").
The program will work in exclusive mode but setting exclusive to
"false" will not change this.
procedure THoofdvenster.MenuItem3Click(Sender: TObject);
begin
   hoofdvenster.Dbf1.Active:=true  ;
   hoofdvenster.Dbf1.PackTable;
   hoofdvenster.Dbf1.Exclusive:=false;
   hoofdvenster.Dbf1.RegenerateIndexes;
   form_lijsten.Dbf2.RegenerateIndexes;
end;
In the program i can not override the exlusive option  from the object
inspector.

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fred · 2017-09-21 13:47

You can only change Exclusive when the database is closed/active =
false

From the TDbf.pdf file:

Quote7.12 Exclusive
property Exclusive: Boolean read FExclusive write FExclusive default
false;
Use Exclusive to prevent other applications from accessing a table
while it is open in this
application. Before opening the table, set Exclusive to true. A table
must be closed before
changing the Exclusive property.
When Exclusive is true, then when the application successfully opens
the table, no other
application can access it. If the table for which the application has
requested exclusive access
is already in use by another application, an exception is thrown. To
handle such exceptions,
wrap the code that opens the table in a try..catch block. See also
TryExclusive.

Do not set Exclusive to true at design time if you also set the Active
property to true at
design time. In this case an exception is thrown because the table is
already in use by the
IDE.

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avra · 2017-09-21 15:51

Quote from: MVD on September 21, 2017, 02:58:23 pmI am sure that de
DBF is not used, so normal "exclusive" must be OK.If you forgot to
uncheck TDBF's Active property in design mode, then in runtime you
have 2 active users on the same DBF.

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MVD · 2017-09-21 19:50

Quote from: avra on September 21, 2017, 05:51:07 pmQuote from: MVD on
September 21, 2017, 02:58:23 pmI am sure that de DBF is not used, so
normal "exclusive" must be OK.If you forgot to uncheck TDBF's Active
property in design mode, then in runtime you have 2 active users on
the same DBF. 
T :Dhanks, this is the solution, it seems as simple as one thinks
about it.

Fred, where did you find the TDbf.pdf file?

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fred · 2017-09-22 06:58

I have the (old) TDbf.pdf from here: https://sourceforge.net/projects/
tdbf/files/TDbf%20documentation/TDbf%20documentation%201.1/