Exam 10: Transaction Management and Concurrency Control

A shared lock produces no conflict as long as all the concurrent transactions are read-write only.

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.

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

A _____ lock will lock the entire table, preventing access to any row by a transaction while another transaction is using the table.

The scheduler establishes the order in which the operations within concurrent transactions are executed.

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

Of the following events, which is defined by ANSI as being equivalent to a COMMIT?

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

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

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

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

The _____ rule states that only one transaction at a time can own an exclusive lock on the same object.

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

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.

A single-user database system automatically ensures_____ of the database, because only one transaction is executed at a time.

Time stamps must only have the single property of uniqueness.

A(n) ______ occurs when a transaction executes a query at time T1, and it runs the same query at same time T2, yielding additional rows that satisfy the query.

The _____ isolation level ensures that queries return consistent results.

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

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