Exam 10: Transaction Management and Concurrency Control

Atomicity indicates the permanence of the database's consistent state.

A(n) occurs when a transaction executes a query at time t1, and then it runs the same query at time t2, yielding additional rows that satisfy the query.

To ensure consistency of the database, every transaction must begin with the database in an unstable state.

In the wait/die scheme,:

are required to prevent another transaction from reading inconsistent data.

What is a rule that applies to the two-phase locking protocol?

A scheduler facilitates data isolation to ensure that two transactions do not update the same data element at the same time.

The phenomenon of uncommitted data occurs when two transactions are executed concurrently and the first transaction is rolled back after the second transaction has already accessed the uncommitted data-thus violating the isolation property of transactions.

Time stamping demands a lot of system resources because many transactions might have to be stopped, rescheduled, and stamped.

What are database checkpoints?

In a heavily used database management system (DBMS), the prevention and detection of constitutes an important DBMS function.

One of the three most common data integrity and consistency problems is .

The manager is responsible for assigning and policing the locks used by the transactions.

Uniqueness ensures that no equal time stamp values can exist, and ensures that time stamp values always increase.

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

A field-level lock allows concurrent transactions to access the same row, as long as they require the use of different fields within that row.

The isolation level ensures that queries return consistent results.

The implicit beginning of a transaction is .

How do transaction recovery procedures use the deferred-write and write-through techniques to recover transactions?

As a rule, a(n) must unlock the object after its termination.