Database Management: Quiz 9

When a transaction reads a row that has been changed, but the change has not been committed, this is known as a ________. Dirty read Clean read Nonrepeatable read Phantom read

Dirty read

Which of the following is not true about two-phased locking? Has a shrinking phase Cannot obtain a new lock once a lock has been released Has a growing phase Uses only shared locks

Uses only shared locks

Locks that are placed assuming that a conflict will occur are called ________. optimistic locks explicit locks pessimistic locks implicit locks

pessimistic locks

One remedy for the inconsistencies caused by concurrent processing is ________. resource locking concurrency checkpointing rollback

resource locking

Measures that are taken to prevent one user's work from inappropriately influencing another user's work are called ________. checkpoint database recovery database logging concurrency control

concurrency control

Once processing rights have been defined, they may be implemented at any of these levels except ________. application network data operating system

data

The task of diagnosing errors due to changes in the database structure is eased by ________. database structure change documentation configuration control formal policies for requesting changes rollback analysis

database structure change documentation

The situation that occurs when two users are each waiting for a resource that the other person has locked is known as a(n) ________. inconsistent read problem lost update problem checkpoint deadlock

deadlock

A lock placed automatically by the DBMS is called a(n) ________ lock. explicit exclusive shared implicit

implicit

The situation that occurs when one user's changes to the database are lost by a second user's changes to the database is known as the ________. inconsistent read problem lost update problem deadly embrace problem inconsistent write problem

lost update problem

Locks that are placed assuming that a conflict will not occur are called ________. shared pessimistic optimistic dynamic

optimistic

Which of the following is not true of DBMS security features? Objects have many permissions. Both users and roles can have many permissions. A role may be assigned to only one user. Users may be assigned to one or more roles.

A role may be assigned to only one user.

Which type of data repository is composed of metadata that is created automatically as the system components are created? Active Dynamic Automatic Passive

Active

When two transactions are being processed against the database at the same time ________. they are called concurrent transactions they are usually interleaved they always result in a lost update problem Both they are called concurrent transactions and they are usually interleaved are correct

Both they are called concurrent transactions and they are usually interleaved are correct

Which of the following is true of forward only cursors? Changes made by the transaction are visible only if they occur on rows ahead of the cursor. Current values for each row are retrieved when the application accesses a row. It requires the greatest overhead of any cursor type. All changes of any type from any source are visible.

Changes made by the transaction are visible only if they occur on rows ahead of the cursor.

Requiring all application programs to lock resources in the same order is a technique for preventing what problem? Lost update Exclusive locks Correct Deadlock Concurrent update

Correct

Which of the following is true about making changes to the database structure? Changes do not produce unexpected results because the DBA will have investigated the change thoroughly before implementing it. Formal policies and procedures for requesting a change are not used because they are too limiting. Documentation of when the change was made, how it was made, and why it was made must be created. The DBA need not get input from users on the issue because it is a technical decision.

Documentation of when the change was made, how it was made, and why it was made must be created.

Which of the following would a DBA typically NOT do in managing the DBMS? Tune DBMS product options to accommodate other software in use Install new versions of the operating system, as needed Evaluate new DBMS product features Analyze system performance statistics

Install new versions of the operating system, as needed

Which of the following is not true about locks? Locks may have a database-level granularity. Locks may have a table-level granularity. Locks with small granularity cause more conflicts. Locks with large granularity are easier for the DBMS to administer.

Locks with small granularity cause more conflicts.

When a transaction rereads data that has been changed and finds changes due to committed transactions, this is known as a ________. Clean read Dirty read Phantom read Nonrepeatable read

Nonrepeatable read

Which of the following would not be contained in a transaction log? Permissions Type of operation Time of the action Before images

Permissions

Which of the following is allowed by "Repeatable Read Isolation"? Nonrepeatable reads Dirty reads Phantom reads Both Nonrepeatable reads and Dirty reads are correct

Phantom reads

Which of the following is allowed by "Repeatable Read Isolation"? Nonrepeatable reads Dirty reads Phantom reads Both Nonrepeatable reads and Dirty reads are correct

Phantom reads

Which of the following cannot be enforced in the DBMS or application programs? Security Cursors Processing rights Processing responsibilities Transaction isolation

Processing responsibilities

Which type of lock still allows other transactions to have read-only access to the locked resource? Exclusive lock Shared lock Implicit lock Explicit lock

Shared lock

Which of the following is not true of data repositories? They may be virtual. They may contain metadata about database applications. They may contain metadata about users. They are usually created after the database has been implemented and optimized for performance.

They are usually created after the database has been implemented and optimized for performance.

Which of the following is not a database administration responsibility of a DBA? Managing the DBMS Writing the applications Maintaining the data repository Managing the database structure

Writing the applications

Recovering a database via rollforward involves ________. restoring the database from the save and reprocessing all the transactions since the save restoring the database from the save and reapplying all the changes made by transactions since the save undoing the changes made by erroneous or partially processed transactions and restarting the valid transactions that were in process at the time of the failure re-creating the database by re-entering all of the data from the beginning, and then reprocessing all of the transactions

restoring the database from the save and reapplying all the changes made by transactions since the save

Recovering a database via reprocessing involves ________. recreating the database by reentering all of the data from the beginning, and then reprocessing all of the transactions undoing the changes made by erroneous or partially processed transactions and restarting the valid transactions that were in process at the time of the failure restoring the database from the save and reapplying all the changes made by transactions since the save restoring the database from the save and reprocessing all the transactions since the save

restoring the database from the save and reprocessing all the transactions since the save

A series of actions to be taken on the database such that either all actions are completed successfully, or none of them can be completed, is known as a ________. lock checkpoint log transaction

transaction

Ensuring that all rows impacted by the actions of a transaction are protected from changes until the entire transaction is completed is called ________. durable transactions transaction level consistency optimistic locking statement level consistency

transaction level consistency

Recovering a database via rollback involves ________. restoring the database from the save and reapplying all the changes made by transactions since the save undoing the changes made by erroneous or partially processed transactions and restarting the valid transactions that were in process at the time of the failure re-creating the database by re-entering all of the data from the beginning and, then reprocessing all of the transactions restoring the database from the save and reprocessing all the transactions since the save

undoing the changes made by erroneous or partially processed transactions and restarting the valid transactions that were in process at the time of the failure