4. To ensure that the results obtained when more than one user processes the database are consistent with what is expected.
7. A high level of control granularity means easy administration for the DBMS but poor throughput.
A low level of control granularity means difficult administration for the DBMS, but better throughput.
8. Atomicity states that database modifications must follow an all or nothing rule. Each transaction is said to be atomic. If one part of the transaction fails, the entire transaction fails. It is critical that the database management system maintain the atomic nature of transactions in spite of any DBMS, operating system or hardware failure.
9. With concurrent transactions, two or more users access the DB using a single CPU on the DB server. The CPU executes some instructions from one, and then executes some for the other, switching back and forth between them. The actions may appear simultaneous to the two users. For transactions to be processed simultaneously, two or more CPU's are required. With modern server computers, such processing is possible.
10. The lost update problem occurs when two transactions attempt to update the same data resource simultaneously. Because each transaction copies the record into its own work area, each can make changes to its own work area, then rewrite their work area to a database. The second update will destroy the first update, thus creating a lost update for the first transaction. Example: you withdraw money from an atom; a friend withdraws money from the same account at the same time at a different atm.
11.
Dirty read: The meaning of this term is as bad as it sounds. You're permitted to read uncommitted, or dirty, data. You can achieve this effect by just opening an OS file that someone else is writing and reading whatever data happens to be there. Data integrity is compromised, foreign keys are violated, and unique constraints are ignored.
No repeatable read: This simply means that if you read a row at time T1 and try to reread that row at time T2, the row may have changed. It may have disappeared, it may have been updated, and so on.
Phantom read: This means that if you execute a query at time T1 and re-execute it at time T2, additional rows may have been added to the database, which may affect your results. This differs from a no repeatable read in that with a phantom read, data you already read hasn't been changed, but instead, more data satisfies your query criteria than before.

12. Exclusive lock allows no other access; shared lock allows other transactions to read but not update the data.

13. Ths size of a locked data element. The lock of a column value of a particular row is a small granularity lock, and the lock of an entire table is a large granularity lock.
14.
15. The procedure by which looks are obtained and released in two phases. During the growing phase, the locks are obtained, and during the shrinking phase, the locks are released. After a lock is released, no other lock will be granted that transaction. Such a procedure ensures consistency in database updates in a concurrent-processing environment.
17. Deadlock occurs when two transactions are each waiting on a resource that the other transaction holds. Deadlock can be prevented by requiring transactions to acquire all locks at the same time; once it occurs, the only way to cure it is to abort one of the transactions and back out of partially completed work.
18. Optimistic locking: a locking strategy that assumes no conflict will occur, processes a transaction, and then checks to determine whether conflict did occur.
Pessimistic locking: a locking strategy that prevents conflict by placing locks before processing database read and write request.
21. ACID means Atomic, Consistency, Isolation, Durability, so when any transaction happen it should be Atomic that is it should either be complete or fully incomplete. There should not be anything like Semi complete. The Database State should remain consistent after the completion of the transaction. If there are more than one Transaction then the transaction should be scheduled in such a fashion that they remain in Isolation of one another. Durability means that once a transaction commits, its effects will persist even if there are system failures.
24. They exist to provide flexibility in the degree of isolation between the works of different transactions.
29. A movable indicator on a computer screen identifying the point that will be affected by input from the user, for example showing where typed text will be inserted.
32. The application can only move forward through the records, and changes made by other cursors in the transaction and other transactions will visible only if they occur to rows ahead of the cursor.
33. Takes a snapshot of a relation and processes that snapshot. Changes made using this cursor are visible; changes form otter sources are not available
34. Combine some features of static cursors with some features of dynamic cursors
35. Full featured cursor; all inserts, updates, deletions, and changes in row order are visible to dynamic cursor.
38. Users, roles and objects have many permissions.
39.
40. Advantages: can be tailored to unique requirements. Can provide horizontal security.
Disadvantages: Maybe done poorly or inconsistently, must be programmed and maintained, may not be as robust.
42. Rollback is when we correct mistakes caused by erroneous or partially processed transactions by undoing the changes they made in the database. Then the valid transactions that were in process at the time of the failure are restarted. Roll forward means the database is restored using the saved data and all valid transactions since the save are reapplied.
43. The most important objective to write the log before the database is changed is if there is any need to rollback or roll forward any transaction then if the log are not present then the rollback roll forward cannot be done accurately.
46. They can be taken automatically by the DBMS. In the event of a needed recovery, they can be used to perform recovery because they provide a point of synchronization between the log and the DB. This is faster than recovering the entire DB from a backup and then applying all after images since the backup was taken.