>What happens is that occationally and only when accessing tables on the network one of te records does not get updated in the inventory table. What is suppose to happen ist that user enters a recieved quantity and date for 1 or more records. Then those fileds are suppose to be updated in the vendor orders line items table and related calculated fields in the inventory table are suppose to be updated. This is a multi-user application. What I am looking for is hints on how to track down the problem and then fix it.

What I suggested was intended to help track down the problem (ie. Error Handling).

The way I usually handle transactions that update "masters" is to lock the masters, insert the transactions, update the masters, and unlock the masters. If a lock fails (which is determined via "error handling"), or an insert fails (more error handling), or the master update fails (another error), the complete transaction has to be retried or restarted.

The code that was illustrated made no provisions for "errors"; it basically assumed that there would never be a problem, whatever the reason ... with no provisions for allowing either the app or the user to retry the transaction.

(FWIW, multi-user can be simulated on a single computer by starting up multiple instances of the application).