What are the conditions under which a deadlock  situation may arise?

A program called lsu [104] gives access to role accounts. The user's access rights are checked, and the user is required to enter her password. If access rules allow the change and the user's password is correct, lsu allows the change. Given that Mary uses lsu from her account, why does lsu require her to enter her password? Name the principles involved, and why they require this

May I request an illustration of the operational mechanics of the queuing process?

A connection like sec course may be built from a collection of many-to-one connections. To what extent do the primary and foreign key restrictions enforce the many-to-one cardinality limitation of the relation? I was wondering why you came to that conclusion.