Database Processing, 15e (Kroenke)
Chapter 9: Managing Multiuser Databases
1) Database administration tasks must be performed for single-user, personal databases.
2) Database administration is more important, but less difficult, in multiuser database systems
than single-user database systems.
3) In general, the overall responsibility of the DBA is to facilitate the development and use of the
database system.
4) The DBA must find a balance between the conflicting goals of maximizing availability of the
database to users and protecting the database.
5) The DBA is responsible for managing changes to the database structure, but is rarely involved
in the original design of the structure.
6) Changes in the database structure usually involve only one application.
7) The database is most vulnerable to failure after a change to its structure.
8) One important reason for documenting changes to the database structure is for diagnosing
errors.
9) Concurrency control measures are taken to ensure that one user’s work has absolutely no
influence on another user’s work.
10) A transaction is sometimes called atomic because it is performed as a unit.
11) A transaction is a series of actions to be taken on the database such that either all of them are
performed successfully or none of them is performed at all.
12) A transaction is a group of alternative database actions, from which the database can choose
to perform only one of them.
13) The size of a lock is referred to as the lock granularity.
14) An exclusive lock locks the item from access of any type.
15) An exclusive lock locks the item from change, but not from read access.
16) Resource locking is one remedy to the lost update problem.
17) Locks placed by a command issued to the DBMS from the application program are called
explicit locks.
18) Locks placed automatically by the DBMS are called implicit locks.
19) Explicit locks are locks that are placed automatically by the DBMS.
20) Locks with large granularity are easy for the DBMS to administer, but frequently cause
conflicts.
21) Two-phased locking is a scheme for achieving serializability of transactions.
22) Two-phased locking has a growing phase and a shrinking phase.
23) In two-phase locking, all locks are obtained during the growing phase.
24) In two-phase locking, all locks are released during the contracting phase.
25) Resource locking must be carefully planned because most DBMS products cannot detect a
deadlock condition.
26) Requiring all application programs to lock resources in the same order is one way of
preventing a deadlock condition.
27) With optimistic locking, the assumption is made that no conflict will occur.
28) With pessimistic locking, the assumption is made that a conflict will occur.
29) Resources are locked for a shorter amount of time with pessimistic locking because the
transaction is pre-processed.
30) In general, optimistic locking is the preferred technique for Internet databases.
31) The transaction boundaries are the essential information that the DBMS needs from the
application programs to enforce different locking strategies.
32) A durable transaction is one for which all committed changes are permanent.
33) Transaction level consistency means that all rows impacted by any actions in a transaction
are protected from change during the entire transaction.
34) A dirty read happens when one transaction reads a changed record that has not been
committed to the database.
35) Nonrepeatable reads occur when a transaction rereads data it has previously read and finds
modifications or deletions caused by a committed transaction.
36) Repeatable Read isolation is the most restrictive level of isolation.
37) According to ANSI SQL, the serializable isolation level will not allow phantom reads, dirty
reads, and nonrepeatable reads.
38) A static cursor processes a snapshot of the relation that was taken when the cursor was
opened.
39) 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.
40) The goal of database security is to ensure that only authorized users can perform authorized
activities at authorized times.
41) Regarding database security, neither the DBMS nor the database applications can enforce
processing responsibilities.
43) Processing rights may be implemented at the DBMS level.
44) All commercial DBMS products use some version of “username and password” as part of
their security features.
45) The security provided by the DBMS often must be augmented by additional security features
within the application program.
46) A database save is used to mark the end of a transaction.
47) A checkpoint is a point of synchronization between the database and the transaction log.
48) 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.
49) Copies of each database record or page after it was changed by a transaction that are saved
for use in database recovery are called ghost images.
50) Reprocessing is normally the most convenient method for recovery after a system failure.
51) Rollforward is a method of database recovery that restores the database save and all valid
transactions since the save was reapplied.
52) Rollforward and reprocessing are two different names for the same technique.
53) To support rollforward and rollback recovery, transactions must be written to a script before
they are applied to the database.
54) Both rollforward and rollback require the use of a log of transaction results.
55) The DBA should periodically analyze run-time statistics of database performance to help
manage the DBMS.
56) An active data repository is one in which the metadata is automatically created as the system
components are created.
57) A standby data repository is one which requires a person to generate the metadata and place
it in the repository.
58) A passive data repository is preferred over an active repository because it requires less
human intervention.
59) Which of the following is not a database administration responsibility of a DBA?
A) Managing the database structure
B) Writing the applications
C) Managing the DBMS
D) Maintaining the data repository
60) Which of the following is true about making changes to the database structure?
A) The DBA need not get input from users on the issue because it is a technical decision.
B) Formal policies and procedures for requesting a change are not used because they are too
limiting.
C) Documentation of when the change was made, how it was made, and why it was made must
be created.
D) Changes do not produce unexpected results because the DBA will have investigated the
change thoroughly before implementing it.
61) The task of diagnosing errors due to changes in the database structure is eased by ________.
A) formal policies for requesting changes
B) database structure change documentation
C) rollback analysis
D) configuration control
62) Measures that are taken to prevent one user’s work from inappropriately influencing another
user’s work are called ________.
A) concurrency control
B) checkpoint
C) database recovery
D) database logging