23909197
Descripción
Test por Craig Willey, actualizado hace más de 1 año
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Creado por Craig Willey
hace más de 4 años
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Pregunta 1
Pregunta
All transaction properties must display ____
Respuesta
-
atomicity, serializability, and durability
-
durability and isolation
-
serializability, durability, and isolation
-
atomicity, durability, serializability, and isolation
Pregunta 2
Pregunta
A ____ lock prevents the use of any tables in the database from one transaction while another transaction is being processed
Respuesta
-
database-level
-
table-level
-
page-level
-
row-level
Pregunta 3
Pregunta
A ____ lock locks the entire table preventing access to any row by a transaction while another transaction is using the table.
Respuesta
-
database-level
-
table-level
-
page-level
-
row-level
Pregunta 4
Pregunta
A ____ lock locks the entire diskpage.
Respuesta
-
transaction-level
-
table-level
-
page-level
-
row-level
Pregunta 5
Pregunta
A ____ lock allows concurrent transactions to access different rows of the same table.
Respuesta
-
database-level
-
table-level
-
page-level
-
row-level
Pregunta 6
Pregunta
A(n) ____ lock has only two stages (0 & 1).
Respuesta
-
shared
-
exclusive
-
binary
-
two-phase
Pregunta 7
Pregunta
A(n) ____ specifically reserves access to the transaction that locked the object.
Respuesta
-
shared lock
-
exclusive lock
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binary lock
-
deadlock
Pregunta 8
Pregunta
A(n) ____ lock exists when concurrent transactions are granted read access on the basis of a common lock.
Respuesta
-
shared
-
exclusive
-
binary
-
two-phase
Pregunta 9
Pregunta
A(n) ____ lock defines how transactions acquire and relinquish locks.
Respuesta
-
shared
-
exclusive
-
binary
-
two-phase
Pregunta 10
Pregunta
A(n) ____ condition occurs when two transactions wait for each other to unlock data.
Respuesta
-
deadlock
-
exclusive lock
-
binary lock
-
two-phase lock
Pregunta 11
Pregunta
Which of the following rules applies to the two-phase locking protocol?
Respuesta
-
Two transactions cannot have conflicting locks.
-
No unlock operation can precede a lock operation in a different transaction.
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No data is affected until all locks are released.
-
No data is affected until the transaction is in its locked position.
Pregunta 12
Pregunta
____ control is the management of concurrent transaction execution.
Respuesta
-
Concurrency
-
Lock
-
Transaction
-
Database
Pregunta 13
Pregunta
The most common algorithms for concurrency control are locks, ____ stamping, and optimistic methods.
Respuesta
-
date
-
time
-
hour
-
minute
Pregunta 14
Pregunta
____ requires that all operations of a transaction be completed.
Respuesta
-
Specificity
-
Atomicity
-
Durability
-
Time stamping
Pregunta 15
Pregunta
____ means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.
Respuesta
-
Serializability
-
Atomicity
-
Isolation
-
Time stamping
Pregunta 16
Pregunta
When you read from and/or write to a database, you have created a(n) ____.
Respuesta
-
transaction
-
back up
-
update
-
queue
Pregunta 17
Pregunta
A transaction is a ____ unit of work that must be either entirely completed or aborted.
Respuesta
-
timed
-
practical
-
logical
-
physical
Pregunta 18
Pregunta
The ANSI has defined standards that govern SQL database transactions. Transaction support is provided by two SQL statements: ____ and ROLLBACK.
Respuesta
-
RETRIEVE
-
ASSIGN
-
UPDATE
-
COMMIT
Pregunta 19
Pregunta
The ____ establishes the order in which the operations within concurrent transactions are executed.
Respuesta
-
transaction log
-
timer
-
lock manager
-
scheduler
Pregunta 20
Pregunta
The ____ manager is responsible for assigning and policing the locks used by the transactions.
Respuesta
-
transaction
-
database
-
lock
-
schedule
Pregunta 21
Pregunta
Lock ____ indicates the level of lock use.
Respuesta
-
granularity
-
shrinking
-
growing
-
serializability
Pregunta 22
Pregunta
During the ____ phase, the transaction scans the database, executes the needed computations, and makes the updates to a private copy of the database values.
Respuesta
-
read
-
validation
-
write
-
shared
Pregunta 23
Pregunta
During the ____ phase, the changes are permanently applied to the database.
Respuesta
-
read
-
validation
-
write
-
shared
Pregunta 24
Pregunta
During the ____ phase, the changes are permanently applied to the database.
Respuesta
-
read
-
validation
-
write
-
shared
Pregunta 25
Pregunta
A(n) ____ backup of the data is when only the last modifications done to the database are copied.
Respuesta
-
differential
-
complete
-
partial
-
incomplete
Pregunta 26
Pregunta
A transaction that changes the contents of the database must alter the database from one ____ state to another.
Respuesta
-
consistent
-
dependent
-
independent
-
inconsistent
Pregunta 27
Pregunta
When is the implicit beginning of a transaction?
Respuesta
-
When the database is started
-
When a table is accessed for the first time
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When the first SQL statement is encountered
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When the COMMIT command is issued
Pregunta 28
Pregunta
A(n) ____ phase in a two-phase lock is when a transaction releases all locks and cannot obtain any new lock.
Respuesta
-
growing
-
shrinking
-
locking
-
unlocking
Pregunta 29
Pregunta
The ____ approach is based on the assumption that the majority of the database operations do not conflict.
Respuesta
-
default
-
basic
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scheduled
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optimistic
Pregunta 30
Pregunta
A diskpage, or page, is the equivalent of a ____.
Respuesta
-
database table
-
disk sector
-
database schema
-
diskblock
Pregunta 31
Pregunta
The ____ is responsible for assigning and policing the locks used by the transactions.
Respuesta
-
lock manager
-
scheduler
-
DBA
-
transaction log
Pregunta 32
Pregunta
What is a consistent database?
Respuesta
-
One in which all tables have foreign keys
-
One in which all data integrity constraints are satisfied
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One in which all tables are normalized
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One in which all SQL statements only update one table at a time
Pregunta 33
Pregunta
A transaction acquires a ____ prior to data access.
Respuesta
-
grain
-
timestamp
-
lock
-
key
Pregunta 34
Pregunta
Changes are permanently applied to the database during the ____ phase of a transaction.
Respuesta
-
commit
-
write
-
input
-
output
Pregunta 35
Pregunta
The ____ approach to scheduling concurrent transactions assigns a global unique stamp to each transaction.
Respuesta
-
scheduled
-
table-locking
-
unique
-
time-stamping
Pregunta 36
Pregunta
All transactions are controlled and executed by the ____ to guarantee database integrity.
Respuesta
-
scheduler
-
DBMS
-
transaction log
-
DBA
Pregunta 37
Pregunta
You can define ____ to help the DBMS ensure that the database remains in a consistent state.
Respuesta
-
integrity constraints
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business rules
-
lock-level transactions
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stored procedures
Pregunta 38
Pregunta
By its nature, a single-user database system automatically ensures ____ of the database, because only one transaction is executed at a time.
Respuesta
-
serializability and durability
-
atomicity and isolation
-
serializability and isolation
-
atomicity and serializability
Pregunta 39
Pregunta
The information stored in the ____ is used by the DBMS for a recovery requirement triggered by a ROLLBACK statement, a program’s abnormal termination, or a system failure such as a network discrepancy or a disk crash.
Respuesta
-
data dictionary
-
metadata
-
rollback manager
-
transaction log
Pregunta 40
Pregunta
Which of the following is NOT stored in the transaction log?
Respuesta
-
The type of operation performed
-
A record for the beginning of a transaction
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The name of the table
-
The number of affected records
Pregunta 41
Pregunta
What is one of the three most common data integrity and consistency problems?
Respuesta
-
Lost updates
-
Disk failures
-
User errors
-
Deadlocks
Pregunta 42
Pregunta
The phenomenon of ____ occurs when two transactions, T1 and T2, are executed concurrently and the first transaction (T1) is rolled back after the second transaction (T2) has already accessed the uncommitted data—thus violating the isolation property of transactions.
Respuesta
-
lost updates
-
uncommitted data
-
transaction failure
-
inconsistent retrieval
Pregunta 43
Pregunta
____ occur when a transaction calculates some summary (aggregate) functions over a set of data while other transactions are updating the data.
Respuesta
-
Lost updates
-
Uncommitted data
-
Transaction failures
-
Inconsistent retrievals
Pregunta 44
Pregunta
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.
Respuesta
-
shared
-
common
-
unrelated
-
locked
Pregunta 45
Pregunta
The scheduler facilitates data ____ to ensure that two transactions do not update the same data element at the same time.
Respuesta
-
durability
-
isolation
-
atomicity
-
serializability
Pregunta 46
Pregunta
What is the most restrictive lock granularity?
Respuesta
-
Database
-
Table
-
Page
-
Row
Pregunta 47
Pregunta
Which lock granularity has the highest overhead?
Respuesta
-
Database
-
Table
-
Row
-
Field
Pregunta 48
Pregunta
A ____ lock has only two states.
Respuesta
-
shared
-
binary
-
database
-
row-level
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