>I am wondering what approaches have been devised to efficiently requery views in a multi-user VFP application.
>
>You ideally would like to have every user see the latest data at all times. On a system with lots of users making changes on large data sets, this may not be feasible from a performance standpoint.
>
>How can you balance the contradictory goals of good performance and up-to-date data?
>
>To detect changes made by other users, I suppose you must call REFRESH(), then OLDVAL() and CURVAL() on the subset of fields you are interested for each alias concerned. This requires a lot of setup and instance code for each situation, and I am not sure how efficient it would be.
>
>For record-oriented data entry forms, this might be sufficient, but for grids you can't easily find out if records other than the one you are on have changed. How can you efficiently keep a grid up-to-date when other users are constantly changing the view bound to the grid?
>
>I have seen systems that use a timer to keep requerying the grid record source whenever the user has been sitting on one record for some minimum interval, but this seems to incur too much overhead. Requerying unconditionally on every form and page activate also seems like overkill.
>
>Are there any books or magazine articles that deal with this subject in detail?

We have tried a requery button for supervisors that need to be advised of recent changes. Then when ever they want to see updated data, they simply hit the requery button.