JDBC Interview Questions

Here is a collection of most of the interview questions in JDBC.

Explain what do you mean by JDBC?

Short for Java Database Connectivity, a Java API that enables Java programs

to execute SQL statements. This allows Java programs to interact with any SQL-compliant

database. Since nearly all relational database management systems (DBMSs) support SQL, and

because Java itself runs on most platforms, JDBC makes it possible to write a single database

application that can run on different platforms and interact with different DBMSs.
JDBC is similar to ODBC, but is designed specifically for Java programs,

whereas ODBC is language-independent

What are the components that constitute JDBC ?

JDBC Components include connection Pools, Data Sources, and MultiPools

How to you load the drivers in JDBC?

Class.forName() method is used in JDBC to load the JDBC drivers

dynamically

What do you mean by batch updates ?

if you want to execute a set of statements, i.e. SQL statements at a time

then we use batch update statement.
resultset=pst.batchUpdate();

Explain how you can establish a connection ?

Loading Drivers
Class.forName(“Driver”);
Getting connection
Connection con = DriverManager.getConnection(url,”myLogin”,

“myPassword”);

What are the  different types of statements in JDBC ?

java.sql.Statement – Top most interface which provides basic methods useful

for executing SELECT, INSERT, UPDATE and DELETE SQL statements.
java.sql.PreparedStatement – An enhanced verion of java.sql.Statement which

allows precompiled queries with parameters. It is more efficient to use

java.sql.PreparedStatement if you have to specify parameters to your SQL queries.
java.sql.CallableStatement – Allows you to execute stored procedures within

a RDBMS which supports stored procedures (MySQL doesn’t support stored procedures at the

moment).

Have you used prepared statements? Where have you used prepared statements ?

Yes. If you want to execute a Statement object many times, it will normally

reduce execution time to use a PreparedStatement object instead.
The main feature of a PreparedStatement object is that, unlike a Statement

object, it is given an SQL statement when it is created. The advantage to this is that in most

cases, this SQL statement will be sent to the DBMS right away, where it will be compiled. As a

result, the PreparedStatement object contains not just an SQL statement, but an SQL statement

that has been precompiled. This means that when the PreparedStatement is executed, the DBMS can

just run the PreparedStatement ‘s SQL statement without having to compile it first.
Although PreparedStatement objects can be used for SQL statements with no

parameters, you will probably use them most often for SQL statements that take parameters. The

advantage of using SQL statements that take parameters is that you can use the same statement

and supply it with different values each time you execute it.