Databases Reference
In-Depth Information
8.
An uncommitted read is also known as which of the following?
(a)
dirty read
(b)
phantom read
(c)
nonrepeatable read
(d)
inconsistent analysis
9.
What is a phantom read?
(a)
reading data that is changed, but not committed
(b)
reading data that is committed, but not written to the hard disk
(c)
reading a range of rows, with one or more rows missing on a subse-
quent read
(d)
data that is changed after it is read by a transaction
10.
Which of the following is NOT a method for minimizing the occurrence
of concurrency errors?
(a)
Keep transaction size to a minimum.
(b)
Segregate additional operations as nested transactions.
(c)
Have all transactions access resources in the same order.
(d)
Keep resources open for as short a time as possible.
11.
Which concurrency method assumes that transaction interaction is
unlikely, so the transaction processor does not check for potential
conflicts?
(a)
locking
(b)
timestamp ordering
(c)
Optimistic processing
(d)
transaction scheduling
12.
Which locking level is less likely to cause a blocked transaction?
(a)
server
(b)
database
(c)
table
(d)
row
13.
A transaction will acquire a shared locked before modifying data to pre-
vent other transactions from accessing the same data. True or False?
14.
Database servers use concurrent transaction processing to improve perfor-
mance and optimize processor use. True or False?
15.
SQL Server 2005 transaction isolation support is limited to isolation lev-
els specified in the SQL-99 standard. True or False?
16.
Which transaction isolation level is the least restrictive?
(a)
read uncommitted
