Exam 10: Transaction Management and Concurrency Control

What is transaction isolation and why it is important?

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

During the ____ phase,changes are permanently applied to the database.

In a page-level lock,the DBMS will lock an entire diskpage.

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

Serializability means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.

ANSI defines four events that signal the end of a transaction.Of the following events,which is defined by ANSI as being equivalent to a ROLLBACK?

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

The optimistic approach is based on the assumption that the majority of the database operations do not conflict.

A ____ lock locks the entire table preventing access to any row by a transaction while another transaction is using the table.

When using an optimistic approach,during the write phase,the transaction is validated to ensure that the changes made will not affect the integrity and consistency of the database.

The ANSI has defined standards that govern SQL database transactions.Transaction support is provided by two SQL statements: ____ and ROLLBACK.

As long as two transactions,T1 and T2,access ____ data,there is no conflict,and the order of execution is irrelevant to the final outcome.

All transactions must display ____.

A(n)____ lock has only two stages (0 and 1).

Lock ____ indicates the level of lock use.

The multiuser DBMS must implement controls to ensure serializability and isolation of transactions,in addition to atomicity and durability,in order to guard the database's consistency and integrity.

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.

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

What are database checkpoints?