Database - Managing Multiuser Database
Database - Managing Multiuser Database
1. Locks placed by command are called ________ .
- implicit locks
- explicit locks
- exclusive locks
- shared locks
2. Which of the following locks the item from change but not from read?
- Implicit lock
- Explicit lock
- Exclusive lock
- 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?
- Nonrepeatable read
- Phantom read
- Dirty read
- Consistent read
4. A transaction for which all committed changes are permanent is called:
- atomic.
- consistent.
- isolated
- durable.
5. In this instance, dirty reads are disallowed, while nonrepeatable reads and phantom reads are allowed.
- Read committed
- Read uncommitted
- Repeatable read
- 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?
- Nonrepeatable read
- Phantom read
- Dirty read
- Consistent read
7. The advantage of optimistic locking is that:
- the lock is obtained only after the transaction has processed.
- the lock is obtained before the transaction has processed.
- the lock never needs to be obtained.
- 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?
- Forward only
- Static
- Keyset
- Dynamic
9. Which of the following refers to a cursor type where changes of any type and from any source are visible?
- Forward only
- Static
- Keyset
- Dynamic
10. Which of the following disallows both dirty reads and nonrepeatable reads, but allows phantom reads?
- Read committed
- Read uncommitted
- Repeatable read
- Serializable