Managing Multiuser Databases The advantage of optimistic locking is that: the lock is obtained only after the transaction has processed. the lock never needs to be obtained. transactions that are best suited are those with a lot of activity. the lock is obtained before the transaction has processed. the lock is obtained only after the transaction has processed. the lock never needs to be obtained. transactions that are best suited are those with a lot of activity. the lock is obtained before the transaction has processed. ANSWER DOWNLOAD EXAMIANS APP
Managing Multiuser Databases The lost update problem is when User A reads data that have been processed by a portion of a transaction from User B. True False True False ANSWER DOWNLOAD EXAMIANS APP
Managing Multiuser Databases A transaction for which all committed changes are permanent is called: consistent. atomic. isolated. durable. consistent. atomic. isolated. durable. ANSWER DOWNLOAD EXAMIANS APP
Managing Multiuser Databases In this instance, dirty reads are disallowed, while nonrepeatable reads and phantom reads are allowed. Read uncommitted Repeatable read Serializable Read committed Read uncommitted Repeatable read Serializable Read committed ANSWER DOWNLOAD EXAMIANS APP
Managing Multiuser Databases The goal of database security is to ensure that only authorized users can perform authorized activities at authorized times. True False True False ANSWER DOWNLOAD EXAMIANS APP
Managing Multiuser Databases 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 Consistent read Phantom read Dirty read Nonrepeatable read Consistent read Phantom read Dirty read ANSWER DOWNLOAD EXAMIANS APP