Thank you Greg, But I think that you've implemented a different behavior than what I'm looking for (or please correct me if I'm wrong!).
What happens if the user modifies the row that a second user has placed a query for? For example, user A access the db first and deletes one row, at the same time user B tried to modify that row, but had to wait because A is working with the db. After A deleted the row, the db is released and B's query to modify a now-deleted row is sent. I would rather just give a message to the user that the db is locked and ask him to come back later than to wait and process that query. And I wish to update user B's db display after A has finished working with the db (I'm thinking of using mailslots for that). Dennis ----- Original Message ----- From: Greg Obleshchuk To: Dennis Volodomanov Sent: Wednesday, October 29, 2003 11:40 AM Subject: Re: [sqlite] Checking the busy state Hi Dennis, I have just done some work on this. Take a look at this wiki page http://www.sqlite.org/cvstrac/wiki?p=MultiThreading The lock is only help while updating. If you follow the instructions in the above page Updates in transactions and you add a loop like the one in the solution then actual SQLITE_BUSY situation should be reduced to a bare minimum. You approach of using a secondary table to write to and see is not the best approach because if the write works there is no guarantee that the write to your primary table will work (someone might get in and still lock it) Yet an update in a transaction if fails will rollback. So the code could look something like begin transaction while not sqlite_busy and retries count not reached update table increase a retries counter if sqlite_busy delay for some time (10ms) loop if not sqlite_busy then commit transaction else rollback transaction regards Greg O ----- Original Message ----- From: Dennis Volodomanov To: [EMAIL PROTECTED] Sent: Wednesday, October 29, 2003 11:07 AM Subject: [sqlite] Checking the busy state Hello, I would like to check for the state of the database before letting the user change any values, because it's on a LAN and could be in use by another machine, but how can I do that without issuing a sqlite_exec() that would attempt to write something and then checking for the SQLITE_BUSY? Is there any way except that? If I understand correctly, I can set up a one-row table for that purpose and before each modification try to write to it and see what the return is? But will I get a SQLITE_BUSY if another table is being used? Does SQLite lock the entire database when it works with it or just one table? I read the explanation of SQLITE_LOCKED, but it didn't answer my question - as I understood it, it means if I screw up somehow then it's issued? Thank you in advance, Dennis
