Sorry if I am asking a trivial question but I have been searching for a while without any luck. I need to design a system and I am looking for advice on the technology that should be used.

The layout is very simple: it is a sales application with a centralized database and multiple clients. Each salesperson has GUI app installed on his/her laptop that should be able to connect to the database to retrieve data and upload data (i.e. register new orders).

My question is the following: how should the communication between the client and the server be implemented? I doubt that connecting directly to the RDBMS is a good idea... Should I use web-services? XML-RPC? How to implement authentication and encode the data?

Thanks for your advice!