>Hi Al,
>
>I am using VMP but unless there is some code that I have not yet found, it does not handle problems when using optimistic file locking. Well, it does allow you to configure a dialog to inform the user that it was not possible to save the changes. Because of that, years ago I incorporated a type of pessimistic file locking. VMP has code that fires on the first keystroke into a field that changes a field. From that central code, I have augmented their code to attempt a file lock. If that fails, then the user is alerted, the view is reverted and the screen flips to being all read-only controls. What I did not do was to apply this to all child tables of the screen. That is, when User #1 gets a lock on the parent record, I do not lock all of the child tables that user #1 might work on. Then when user #2 tries to get a lock on the parent, they cannot and are prevented from continuing with the edit.
>
>That has always worked - until now when a different screen altogether only changes some of the child records - I guess I will need to augment the code in the second screen to also get a lock as soon as someone starts editing a row...will have to think about this a bit as the 2nd user is working with child rows from a bunch of different screens.
>
>Thanks...got me thinking
>
>
>>If you're using a framework such as VMP, does it not handle these details for you if you configure it appropriately?
>>
>>Other than that - have you given any thought to using pessimistic rather than optimistic buffering? I've never used it myself but I understand it's pretty much required in high-contention environments such as airplane and concert/venue ticketing. As I understand it a lot of the issues you're describing could be avoided.
>>
>>You'd need to take measures to avoid "lunch lock" but maybe you could use it minimally in critical sections.
>>

Hey Albert,
VMP has the option of using a semaphore lock when you edit a record. I implemented some VMP apps that used an explicit Edit button and at that point in time I would "lock" the record with a semaphore, so no one else could edit it at the same time.
Not sure that this would help in your situation though. You can find details in the MP help file under "Semaphore Lock" and "setup data-entry forms with an explicit Edit button?"