Question 1

A(n) _____ lock exists when concurrent transactions are granted read access on the basis of a common lock.

Accepted Answer

A shared lock exists when concurrent transactions are granted read access on the basis of a common lock. This means that multiple transactions can hold a shared lock on a resource simultaneously, allowing them to read the resource but not modify it. This ensures that transactions can access the resource without interfering with each other, while still maintaining data consistency.

Question 2

To determine the appropriate order of the operations, the scheduler bases its actions on concurrency control algorithms, such as _____ or time stamping methods.

Accepted Answer

The answer of To determine the appropriate order of the...

Question 3

_____ can take place at any of the following levels: database, table, page, row, or field.

Accepted Answer

The answer of _____ can take place at any of...

Question 4

A(n) _____ specifically reserves access to the transaction that locked the object.

Accepted Answer

An exclusive lock specifically reserves access to the transaction that locked the object. A shared lock allows multiple transactions to read but not modify the locked object while an exclusive lock reserves the object for exclusive use by the transaction that locked it. A binary lock is a type of lock that either grants or denies access to a resource. Deadlock is a situation where two or more transactions are blocked and cannot proceed because they are each waiting for the other to release a resource.

Question 5

The _____ occurs when two concurrent transactions, T1 and T2, are updating the same data element and one of the updates is lost.

Accepted Answer

The answer of The _____ occurs when two concurrent transactions,...

Question 6

In the optimistic approach, during the _____ phase, changes are permanently applied to the database.

Accepted Answer

During the write phase, changes are actually made and permanently applied to the database. The read phase is for getting data from the database, while the validation phase checks if the changes made in the write phase are valid. The shared phase involves multiple transactions accessing the same data simultaneously. Therefore, the correct option is C.

Question 7

Although the DBMS is designed to recover a database to a previous consistent state when an interruption prevents the completion of a required set of transactions, the transactions themselves are defined by the end user or programmer and must be _____ correct.

Accepted Answer

The answer of Although the DBMS is designed to recover...

Question 8

A(n) _____ condition occurs when two or more transactions wait for each other to unlock data.

Accepted Answer

Deadlock occurs when two or more transactions are blocked and are waiting for each other to release the lock on a resource. It is a major problem in database systems and can cause system failure if not handled properly. Exclusive lock, binary lock, and two-phase lock are concepts related to locking mechanisms used to ensure data consistency but they do not directly pertain to a deadlock condition.

Question 9

A(n) _____ phase in a two phase lock is when a transaction releases all locks and cannot obtain a new lock.

Accepted Answer

In a two phase lock, the shrinking phase is when a transaction releases all locks and cannot obtain a new lock. During the shrinking phase, a transaction releases all the locks it acquired during the growing phase and cannot acquire any more locks. This ensures that the transaction does not make any further updates to the database and prepares itself for the commit phase.

Question 10

In the wait/die scheme, the:

Accepted Answer

In the wait/die scheme, if an older transaction requests a lock held by a younger transaction, the older transaction waits. If a younger transaction requests a lock held by an older transaction, the younger transaction is rolled back (dies).

Question 11

Most multiuser _____ automatically initiate and enforce locking procedures, where all locking information is managed by the lock manager.

Accepted Answer

The answer of Most multiuser _____ automatically initiate and enforce...

Question 12

The _____ isolation level ensures that queries return consistent results.

Accepted Answer

Serializable isolation level ensures that queries return consistent results by preventing dirty reads, non-repeatable reads, and phantom reads.

Question 13

What rule applies to the two-phase locking protocol?

Accepted Answer

Two-phase locking protocol ensures that two transactions cannot have conflicting locks, which helps maintain consistency and prevent deadlocks.

Question 14

_____-level locks are less restrictive than database-level locks, but they create traffic jams when many transactions are waiting to access the same table.

Accepted Answer

The answer of _____-level locks are less restrictive than database-level...

Question 15

The _____ interleaves the execution of database operations to ensure serializability.

Accepted Answer

The answer of The _____ interleaves the execution of database...

Question 16

In the optimistic approach, during the_____ phase, a transaction scans the database, executes the needed computations, and makes the updates to a private copy of the database values.

Accepted Answer

In the optimistic approach, the read phase is when a transaction scans the database, executes computations, and updates a private copy of the values.

Question 17

The objective of _____ control is to ensure the serializability of transactions in a multiuser database environment.

Accepted Answer

The answer of The objective of _____ control is to...

Question 18

The scheduler's main job is to create a(n) _____ of a transaction's operation, in which the interleaved executions of transactions yield the same results as if the transactions were executed in serial order.

Accepted Answer

The answer of The scheduler's main job is to create...

Question 19

If a(n) _____ is issued before the termination of a transaction, the DBMS will restore the database only for that particular transaction, rather than for all transactions, in order to maintain the durability of the previous transactions.

Accepted Answer

The answer of If a(n) _____ is issued before the...

Question 20

The _____ approach to scheduling concurrent transactions assigns a global unique stamp to each transaction.

Accepted Answer

The time stamping approach to scheduling concurrent transactions assigns a global unique stamp to each transaction, enabling the scheduler to determine the order in which transactions were initiated and hence the order in which they must be allowed to proceed. This approach ensures that transactions are executed in a serializable manner.

Quiz 10: Transaction Management and Concurrency Control