All transaction properties must display ____
atomicity, serializability, and durability
durability and isolation
serializability, durability, and isolation
atomicity, durability, serializability, and isolation
A ____ lock prevents the use of any tables in the database from one transaction while another transaction is being processed
database-level
table-level
page-level
row-level
A ____ lock locks the entire table preventing access to any row by a transaction while another transaction is using the table.
A ____ lock locks the entire diskpage.
transaction-level
A ____ lock allows concurrent transactions to access different rows of the same table.
A(n) ____ lock has only two stages (0 & 1).
shared
exclusive
binary
two-phase
A(n) ____ specifically reserves access to the transaction that locked the object.
shared lock
exclusive lock
binary lock
deadlock
A(n) ____ lock exists when concurrent transactions are granted read access on the basis of a common lock.
A(n) ____ lock defines how transactions acquire and relinquish locks.
A(n) ____ condition occurs when two transactions wait for each other to unlock data.
two-phase lock
Which of the following rules applies to the two-phase locking protocol?
Two transactions cannot have conflicting locks.
No unlock operation can precede a lock operation in a different transaction.
No data is affected until all locks are released.
No data is affected until the transaction is in its locked position.
____ control is the management of concurrent transaction execution.
Concurrency
Lock
Transaction
Database
The most common algorithms for concurrency control are locks, ____ stamping, and optimistic methods.
date
time
hour
minute
____ requires that all operations of a transaction be completed.
Specificity
Atomicity
Durability
Time stamping
____ means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.
Serializability
Isolation
When you read from and/or write to a database, you have created a(n) ____.
transaction
back up
update
queue
A transaction is a ____ unit of work that must be either entirely completed or aborted.
timed
practical
logical
physical
The ANSI has defined standards that govern SQL database transactions. Transaction support is provided by two SQL statements: ____ and ROLLBACK.
RETRIEVE
ASSIGN
UPDATE
COMMIT
The ____ establishes the order in which the operations within concurrent transactions are executed.
transaction log
timer
lock manager
scheduler
The ____ manager is responsible for assigning and policing the locks used by the transactions.
database
lock
schedule
Lock ____ indicates the level of lock use.
granularity
shrinking
growing
serializability
During the ____ phase, the transaction scans the database, executes the needed computations, and makes the updates to a private copy of the database values.
read
validation
write
During the ____ phase, the changes are permanently applied to the database.
A(n) ____ backup of the data is when only the last modifications done to the database are copied.
differential
complete
partial
incomplete
A transaction that changes the contents of the database must alter the database from one ____ state to another.
consistent
dependent
independent
inconsistent
When is the implicit beginning of a transaction?
When the database is started
When a table is accessed for the first time
When the first SQL statement is encountered
When the COMMIT command is issued
A(n) ____ phase in a two-phase lock is when a transaction releases all locks and cannot obtain any new lock.
locking
unlocking
The ____ approach is based on the assumption that the majority of the database operations do not conflict.
default
basic
scheduled
optimistic
A diskpage, or page, is the equivalent of a ____.
database table
disk sector
database schema
diskblock
The ____ is responsible for assigning and policing the locks used by the transactions.
DBA
What is a consistent database?
One in which all tables have foreign keys
One in which all data integrity constraints are satisfied
One in which all tables are normalized
One in which all SQL statements only update one table at a time
A transaction acquires a ____ prior to data access.
grain
timestamp
key
Changes are permanently applied to the database during the ____ phase of a transaction.
commit
input
output
The ____ approach to scheduling concurrent transactions assigns a global unique stamp to each transaction.
table-locking
unique
time-stamping
All transactions are controlled and executed by the ____ to guarantee database integrity.
DBMS
You can define ____ to help the DBMS ensure that the database remains in a consistent state.
integrity constraints
business rules
lock-level transactions
stored procedures
By its nature, a single-user database system automatically ensures ____ of the database, because only one transaction is executed at a time.
serializability and durability
atomicity and isolation
serializability and isolation
atomicity and serializability
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.
data dictionary
metadata
rollback manager
Which of the following is NOT stored in the transaction log?
The type of operation performed
A record for the beginning of a transaction
The name of the table
The number of affected records
What is one of the three most common data integrity and consistency problems?
Lost updates
Disk failures
User errors
Deadlocks
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.
lost updates
uncommitted data
transaction failure
inconsistent retrieval
____ occur when a transaction calculates some summary (aggregate) functions over a set of data while other transactions are updating the data.
Uncommitted data
Transaction failures
Inconsistent retrievals
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.
common
unrelated
locked
The scheduler facilitates data ____ to ensure that two transactions do not update the same data element at the same time.
durability
isolation
atomicity
What is the most restrictive lock granularity?
Table
Page
Row
Which lock granularity has the highest overhead?
Field
A ____ lock has only two states.