Managing Multiuser Databases – General Questions

6. Which of the following occurs when a transaction rereads data it has previously read and finds modification or deletions caused by a committed transaction?

A. Nonrepeatable read
B. Phantom read
C. Dirty read
D. Consistent read

Correct Answer:  A. Nonrepeatable read

7. The advantage of optimistic locking is that:

A. the lock is obtained only after the transaction has processed.
B. the lock is obtained before the transaction has processed.
C. the lock never needs to be obtained.
D. transactions that are best suited are those with a lot of activity.

Correct Answer:  A. the lock is obtained only after the transaction has processed.

8. Which of the following refers to a cursor type that when the cursor is opened, a primary key value is saved for each row in the recordset; when the application accesses a row, the key is used to fetch the current values of the row?

A. Forward only
B. Static
C. Keyset
D. Dynamic

Correct Answer:  C. Keyset

9. Which of the following refers to a cursor type where changes of any type and from any source are visible?

A. Forward only
B. Static
C. Keyset
D. Dynamic

Correct Answer:  D. Dynamic

10. Which of the following disallows both dirty reads and nonrepeatable reads, but allows phantom reads?

A. Read committed
B. Read uncommitted
C. Repeatable read
D. Serializable

Correct Answer:  C. Repeatable read

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