Database

Database

Managing Multiuser Databases has 40 Questions
Locks placed by command are called ________ .

implicit locks
explicit locks
exclusive locks
shared locks
Resource locking is a process to prevent multiple applications from obtaining copies of the same record when the record is about to be changed.

True
False
Which of the following locks the item from change but not from read?

Implicit lock
Explicit lock
Exclusive lock
Shared lock
The overall responsibility of the DBA is to facilitate the development and use of the database.

True
False
Which of the following occurs when a transaction rereads data and finds new rows that were inserted by a command transaction since the prior read?

Nonrepeatable read
Phantom read
Dirty read
Consistent read
The size of the lock is referred to as the lock granularity.

True
False
A transaction for which all committed changes are permanent is called:

atomic.
consistent.
isolated.
durable.
A durable transaction is one in which all committed changes are permanent.

True
False
In this instance, dirty reads are disallowed, while nonrepeatable reads and phantom reads are allowed.

Read committed
Read uncommitted
Repeatable read
Serializable
An ACID transaction is one that is atomic, consistent isolated, and durable.

True
False
Which of the following occurs when a transaction rereads data it has previously read and finds modification or deletions caused by a committed transaction?

Nonrepeatable read
Phantom read
Dirty read
Consistent read
When one transaction reads a changed record that has not been committed to the database a filthy read occurs.

True
False
The advantage of optimistic locking is that:

the lock is obtained only after the transaction has processed.
the lock is obtained before the transaction has processed.
the lock never needs to be obtained.
transactions that are best suited are those with a lot of activity.
The size of a lock is referred to as lock sizing.

True
False
Which of the following refers to a cursor type that when the cursor is opened, a primary key value is saved for each row in the recordset; when the application accesses a row, the key is used to fetch the current values of the row?

Forward only
Static
Keyset
Dynamic
When two transactions are being processed against the database at the same time they are termed concurrent transactions.

True
False
Which of the following refers to a cursor type where changes of any type and from any source are visible?

Forward only
Static
Keyset
Dynamic
Locks placed by the DBMS are explicit locks.

True
False
Which of the following disallows both dirty reads and nonrepeatable reads, but allows phantom reads?

Read committed
Read uncommitted
Repeatable read
Serializable
In optimistic locking, the assumption is made that conflict will occur.

True
False
Dirty read, nonrepeatable, and phantom reads are not possible in this instance.

Read committed
Read uncommitted
Repeatable read
Serializable
Two transactions that run concurrently and generate results that are consistent with the results that would have occurred if they had run separately are referred to as serializable transactions.

True
False
A transaction in which either all of the database actions occur or none of them do is called:

atomic.
consistent.
isolated.
durable.
The lost update problem is when User A reads data that have been processed by a portion of a transaction from User B.

True
False
A cursor type in which the application can only move forward through the recordset is called:

forward only.
static.
keyset.
dynamic.
The transaction log contains a copy of every database record (or page) after it has changed. These records are called before images.

True
False
Which of the following occurs when one transaction reads a changed record that has not been committed to the database?

Nonrepeatable read
Phantom read
Dirty read
Consistent read
Database administration refers to a function that applies to the entire organization.

True
False
Which of the following allows dirty reads, nonrepeatable reads and phantom reads to occur?

Read committed
Read uncommitted
Repeatable read
Serializable
Locks placed by command are implicit locks.

True
False
Which of the following locks the item from access of any type?

Implicit lock
Explicit lock
Exclusive lock
Shared lock
The goal of database security is to ensure that only authorized users can perform authorized activities at authorized times.

True
False
The size of a lock is called:

implicit lock.
lock granularity.
exclusive lock.
shared lock.
A phantom read occurs when a transaction rereads data it has previously read and finds modifications or deletions caused by a committed transaction.

True
False
A cursor type in which the application sees the data as they were at the time the cursor was opened is called:

forward only.
static.
keyset.
dynamic.
A transaction is a series of actions to be taken on the database so that either all of them are performed successfully or none of them are performed at all.

True
False
What is the overall responsibility of the DBA?

Facilitate the development and use of the database
Create and populate tables
Development, operation, and maintenance of the database and its applications
Both the first and third answers above are correct.
A point of synchronization between the database and the transaction log is generally referred to as a stop point.

True
False
Locks placed by the DBMS are called ________ .

implicit locks
explicit locks
exclusive locks
shared locks
An exclusive lock locks the item from change but not from read.

True
False