Exam 9: Managing Multiuser Databases

Database administration tasks have to be performed for single-user,personal databases.

Concurrency control measures are taken to ensure that one user's work has absolutely no influence on another user's work.

Which of the following is not true of data repositories?

Repeatable Read isolation is the most restrictive level of isolation.

Requiring all application programs to lock resources in the same order is a technique for preventing what problem?

A lock placed automatically by the DBMS is called a(n)________ lock.

A checkpoint is a point of synchronization between the database and the transaction log.

According to ANSI SQL,the serializable isolation level will not allow phantom reads,dirty reads,and nonrepeatable reads.

Which of the following would not be contained in a transaction log?

What is a distributed database?

A transaction is a group of alternative database actions from which the database can choose to perform only one of them.

Explicit locks are locks that are placed automatically by the DBMS.

Distinguish between statement-level consistency and transaction-level consistency.

Resources are locked for a shorter amount of time with pessimistic locking because the transaction is pre-processed.

To support rollforward and rollback recovery,transactions must be written to a script before they are applied to the database.

The DBA is responsible for managing changes to the database structure,but is rarely involved in the original design of the structure.

With optimistic locking,the assumption is made that no conflict will occur.

A static cursor processes a snapshot of the relation that was taken when the cursor was opened.

Locks placed automatically by the DBMS are called implicit locks.

Which are more commonly used: implicit or explicit locks? Why?