Exam 9: Managing Multiuser Databases

An exclusive lock locks the item from access of any type.

Explain the concept of an "atomic transaction."

Two-phased locking is a scheme for achieving serializability of transactions.

The security provided by the DBMS often has to be augmented by additional security features within the application program.

All commercial DBMS products use some version of "username and password" as part of their security features.

Distinguish between the four cursor types.

Explain the purpose of transaction logs and checkpoints.

A dynamic cursor saves primary key values when the cursor is opened and retrieves the values for each row as the application program accesses it.

Database administration is more important but less difficult in multiuser database systems than in single-user database systems.

Explain the concept of serializable transactions.

Briefly explain the strategy of two-phased locking.

Resource locking is one remedy to the lost update problem.

The DBA has to find a balance between the conflicting goals of maximizing availability of the database to users and protecting the database.

Reprocessing is normally the most convenient method for recovery after a system failure.

Resource locking must be carefully planned because most DBMS products cannot detect a deadlock condition.

Transaction level consistency means that all rows impacted by any actions in a transaction are protected from change during the entire transaction.

Copies of each database record or page before being changed by a transaction that are saved for use in database recovery are called before images.

Both rollforward and rollback require the use of a log of transaction results.

In regard to database security,neither the DBMS nor the database applications can enforce processing responsibilities.

The size of a lock is referred to as the lock granularity.