I've been asked to write a program for a small company. They will have just a few users (1 to 4) accessing a database. The database will probably grow to just 20,000 records at the most. If multiple users are accessing simultaneously and one of them adds or updates a record, they want the screens of the other users to be refreshed and reflect the newly added data.

My thought is to write the application in MSVC++ and connect to an MS Access DB using ODBC. My dilemma is in deciding the best way to handle the updating of all the users screens when one user has added a record.

1) I could have the application spawn a thread, which would kickoff a timer. Say every 20 seconds, the timer would run a query against the DB and see if any records have been added. If so, it's time to refresh the data here on this machine.

2) I could also maybe write a service that would run on the server with the database. The application on each users machine would interact with this service, not the database. The service would accept all the requests from the users (clients), interact with the DB and respond to the clients. If a record is added or updated, the service would send a msg or invoke a callback on the client and tell it to update.

3) I'm not sure about this, but I think there also might be some broadcast function/message that I can use.

Does anyone have any suggestions or warnings or previous experience with this?

Thanks very much!
Brian