You work as an Application Developer for Nero Inc. You want to instruct the DBMS to set the transaction
isolation level so that when a user updates a tablein the database, other users cannot read the valueat the
same time. Which of the following methods will you use to define the transaction level?

A.
setTransactionIsolation()

B.
isClosed()

C.
getTransactionIsolation()

D.
supportsTransactions()

Explanation:
The setTransactionIsolation() method of the Connection interface takes an integer as a parameter and sets the
transaction isolation level.
There are five levels of transaction isolation levels provided by JDBC 2.0. The higher the transactionlevel, the
more care is taken to avoid
database conflicts. On the other hand , the higher the level of isolation, the slower the application executes
(due to increased locking
overhead and decreased concurrency between users). The developer must balance the need for performance
with the need for data
consistency when making a decision about what isolation level to use. However, the level that can actually be
supported depends on the
capabilities of the underlying DBMS.
The highest transaction isolation level specifies that if one transaction is operating on a database, no other
transaction can access that part
of the database.
Answer C is incorrect. The getTransactionIsolation() method returns the current isolation mode of the
transaction associated with the
Connection object.
Answer B is incorrect. The isClosed() method of theConnection object returns a Boolean true if the connection
to the database is
closed, and a Boolean false if the database connection is currently open. Answer D is incorrect. The
supportsTransactions() method of the DatabaseMetaData interface is used to determine whether a given
database supports the use of transactions or not. It returns a Boolean true if the database supports a
transaction and a Boolean false if it does not.