JDBC

Question 0

The JDBC classes are part of the packages java.sql.* and javax.sql.*?

Answer 0

Yes

Question 1

JDBC 4.1 introduces RowSet and its related utility classes such as RowSetFactory and RowSetProvider?

Answer 1

Yes

Question 2

Connection interface of the java.sql package represents a connection from application to the database?

Answer 2

Yes

Question 3

You can get a connection object by invoking the DriverManager.getConnection() method; the method expects the URL of the database along with a database name, user name, and password?

Answer 3

Yes

Question 4

Prior to JDBC 4.0, you would have to explicitly load the JDBC driver using the Class.forName() statement, as in the following: Class.forName(“com.mysql.jdbc.Driver”).newInstance(); Connection connection = DriverManager.getConnection(url + database, userName, password)

Answer 4

Yes

Question 5

JDBC provides two important interfaces to support queries: Statement and Resultset.

Answer 5

Yes

Question 6

Statement comes in three flavors: Statement, PreparedStatement, and CallableStatement

Answer 6

Yes

Question 7

when you need to send a SQL statement to the database without any parameter. In normal cases, you need to use…

Answer 7

Statement

Question 8

You can create an instance of Statement using…

Answer 8

…createStatement() method in the Connection interface

Question 9

a precompiled SQL statement that can be customized using IN parameters. Usually, it is more efficient than a Statement object; hence, it is used to improve the performance, especially if a SQL statement is executed multiple times…

Answer 9

PreparedStatement

Question 10

You can get an instance of PreparedStatement by calling the…

Answer 10

preparedStatement() method in the Connection interface.

Question 11

used to execute stored procedures…

Answer 11

CallableStatement

Question 12

to get an instance of CallableStatement…

Answer 12

You need to call the prepareCall() method in the Connection interface to get an instance of this class

Question 13

If your SQL statement is a SELECT query, you can use the … method, which returns a ResultSet

Answer 13

executeQuery()

Question 14

When you want to update a database using one of the INSERT, UPDATE, or DELETE statements, you should use the…() method, which returns an integer reflecting the updated number of rows

Answer 14

executeUpdate()

Question 15

If you don’t know the type of SQL statement, you can use the…() method, which may return multiple resultsets or multiple update counts or a combination of both

Answer 15

execute()

Question 16

ResultSet is a table with column headings and associated values requested by the query…

Answer 16

Yes

Question 17

column index starts from …

Answer 17

1, not from 0

Question 18

always call updateRow() after modifying the row contents; otherwise you will lose the changes

Answer 18

Yes

Question 19

You can get the metadata from a Connection object to examine the capabilities of the underlying database. You can do this by calling the …

Answer 19

getMetaData() method in the Connection interface

Question 20

The boolean absolute(int) method in ResultSet moves the cursor to the passed row number in that ResultSet object

Answer 20

Yes

Question 21

The boolean absolute(int) method if the row number is negative,

Answer 21

…it moves to that position from the end of the ResultSet object. Assume that there are 10 entries in the ResultSet object. Calling absolute(3) will move the cursor to the third row. Calling absolute(−3) will move the cursor to the 10–3, seventh row. If you give out of range values, the cursor will move to either beginning or end

Question 22

In a ResultSet object, calling absolute(1) is equivalent to calling first(), and calling absolute(−1) is equivalent to calling last

Answer 22

Yes

Question 23

Atomicity…

Answer 23

Each transaction should be carried out in its entirety; if one part of the transaction fails, then the whole transaction fails

Question 24

Consistency:

Answer 24

Consistency: The database should be in a valid state before and after the performed transaction

Question 25

Isolation

Answer 25

Isolation: Each transaction should execute in complete isolation without knowing the existence of other transactions

Question 26

Durability:

Answer 26

Once the transaction is complete, the changes made by the transaction are permanent (even in the occurrence of unusual events such as power loss

Question 27

Transaction-Related Methods in the Connection Interface…

Answer 27

void setAutoCommit(boolean autoCommit) 
boolean getAutoCommit() 
Savepoint setSavepoint() 
Savepoint setSavepoint(String name) 
void releaseSavepoint(Savepoint savepoint) 
void rollback(Savepoint savepoint) 
void rollback() void commit

Question 28

You can use column name or column index with ResultSet methods…

Answer 28

Yes The index you use is the index of the ResultSet object, not the column number in the database table

Question 29

It is your responsibility to issue a correct SQL command…

Answer 29

Yes…a JDBC Statement will not check for its correctness. For example, if there is a syntax error in the SQL command string, then you will not get a compiler error. Rather, you’ll get a MySQLSyntaxErrorException at runtime