12.  Appendix 2: Optimistic locking

Suppose, for example, the user wants to change a customer's address. To do this, he performs an activity in the appropriate SF Pilot. It's highly likely that the human-machine interface for this activity will display a range of information about the customer, including the current address. Our user starts to enter the new address, but is interrupted by a phone call. Meanwhile, another user performs an activity that changes the customer's address. Our first user, who resumes his activity at the end of his telephone conversation, is unaware of the modification made by the other user and therefore risks overwriting...