>>1) If a user locks a record, and the computer hangs - will the lock be released automatically?
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>>2) The first question, of course, reveals my lack of knowledge about what "really happens" when I lock a record. If anybody can illuminate me on this point... Are OS-functions called up? Is a bit changed in the memory on the file server?
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>>TIA, Hilmar.
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>Hilmar,
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>A lock is held in memory, ie the os keeps a list of the locks.
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>If your computer hangs, you will either shut it down or reboot. Since the locks are in memory, they are released
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>Above extended to file servers
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>on your pc you lock a record. The lock is held in your pc's memory and also transferred to the server.
>If you try to lock a record, the pc first looks whether it is already locked on your pc. If not, your pc communicates with the server to place a lock. If successful, the lock will reside in your pc as well as the server.
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>Now, if your pc has successfully placed a lock (on the server) and it reboots, there will still be a lock on the server. Some (most of, I think) servers detect that the pc is no longer there and release the lock. Others keep the lock for minutes and time out (release the lock) eventually
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>This is by no means complete, but it gives an idea

Thanks, that's what I wanted to know.

I was thinking to use some scheme to limit the number of users connected simultaneously (example: limit to 5 users). Locking 5 consecutive records in a table seems safer than saving information to a table. For, if the user's computer hangs, he will remain "logged in", if I use a REPLACE scheme.

Hilmar.