ODBC Time connection
lazarus / 16-Databases

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lcapitanache · 2024-05-27 19:23

Hello,

I have an application in Lazarus that connects to a MS Access 2007
database that is on a shared resource on a local network through an
ODBCConnection control. The program works correctly and I can perform
SQL queries without any problem.

However, I have noticed that when the computer hosting the database is
not available, my Lazarus application hangs waiting for the
connection. I have searched, but I see that the ODBCConnection control
does not have a Timeout property to set. In this scenario, how could I
set a connection timeout of, say, two seconds, so that I can display a
database unavailable error message?

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Zvoni · 2024-05-28 05:38

Quote from: lcapitanache on May 27, 2024, 09:23:03 pmHello,

I have an application in Lazarus that connects to a MS Access 2007
database that is on a shared resource on a local network through an
ODBCConnection control. The program works correctly and I can perform
SQL queries without any problem.

However, I have noticed that when the computer hosting the database is
not available, my Lazarus application hangs waiting for the
connection. I have searched, but I see that the ODBCConnection control
does not have a Timeout property to set. In this scenario, how could I
set a connection timeout of, say, two seconds, so that I can display a
database unavailable error message?
Since Access is a filebased database, why don't you just check if the
FileExists (hint!)?

EDIT: Found this:
https://forum.lazarus.freepascal.org/index.php?topic=57218.0
Funny enough: Didn't remember anymore...
No idea if it works for Access

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lcapitanache · 2024-05-29 19:29

Quote from: Zvoni on May 28, 2024, 07:38:00 amQuote from: lcapitanache
on May 27, 2024, 09:23:03 pmHello,

I have an application in Lazarus that connects to a MS Access 2007
database that is on a shared resource on a local network through an
ODBCConnection control. The program works correctly and I can perform
SQL queries without any problem.

However, I have noticed that when the computer hosting the database is
not available, my Lazarus application hangs waiting for the
connection. I have searched, but I see that the ODBCConnection control
does not have a Timeout property to set. In this scenario, how could I
set a connection timeout of, say, two seconds, so that I can display a
database unavailable error message?
Since Access is a filebased database, why don't you just check if the
FileExists (hint!)?

EDIT: Found this:
https://forum.lazarus.freepascal.org/index.php?topic=57218.0
Funny enough: Didn't remember anymore...
No idea if it works for Access

Hi, thank you very much for your time.

I tried your idea of verifying the existence of the database file
first, but I had exactly the same problem. The application hangs
looking for the existence of the file on the host.

I solved the problem by changing the approach a bit. What I did was to
elaborate a function that sends a ping to the computer host, and based
on its response I either open the database or display an
unavailability error message.