I am using the WEB appliaction. In this, two users are chnaging the same field of the same screen simultaneously.
So data inconsistancy is there. This may create problem in my application.
In data base, master as well as children data are changing.
You have two choices:
1) Optimistic - Keep track of when the field was last updated. Don't allow the second update once the last updated time doesn't match.
2) Pessimistic - Set a flag when the first user reads the field. Don't allow updates until the field is reset. (You need a timeout with this approach so it isn't locked forever if the user goes away.)