Suppose the lock hierarchy for a database consists of database, relations, and tuples.

a. If a transaction needs to read a lot of tuples from a relation r, what locks should it acquire?

b. Now suppose the transaction wants to update a few of the tuples in r after reading a lot of tuples. What locks should it acquire?
c. If at run-time the transaction finds that it needs to actually update a very large number of tuples (after acquiring locks assuming only a few tuples would be updated). What problems would this cause to the lock table, and what could the database do to avoid the problem?