Hi. In order to avoid a deadlock in my program a user must call lock then update or delete and then unlock methods. User can't lock a record before he unlocks the previous. But what if the clients machine will crash for some reasons. what if for example the user will call lock then update and then he will crash. If this happen my program will deadlock. So do I nead to solve this problem at all ? And if I do please tell how can I do it.