Managing Multiuser Databases

1.	Locks placed by command are called ________ .
	A. implicit locks B. explicit locks C. exclusive locks D. shared locks

2.	Which of the following locks the item from change but not from read?
	A. Implicit lock B. Explicit lock C. Exclusive lock D. Shared lock

3.	Which of the following occurs when a transaction rereads data and finds new rows that were inserted by a command transaction since the prior read?
	A. Nonrepeatable read B. Phantom read C. Dirty read D. Consistent read

4.	A transaction for which all committed changes are permanent is called:
	A. atomic. B. consistent. C. isolated. D. durable

5.	In this instance, dirty reads are disallowed, while nonrepeatable reads and phantom reads are allowed.
	A. Read committed B. Read uncommitted C. Repeatable read D. Serializable

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

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.

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

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

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