JDBC Interview Questions and Answers Most Frequently Asked

JDBC Experienced Interview Questions and Answers Most Frequently Asked . You can get simple and best definition for JDBC Interview Questions in this page. The following interview Questions are Most Frequently Asked in Interview.

JDBC Interview Questions and Answers Most Frequently Asked . The following interview Questions are Most Frequently Asked in Interview.
1) What are the steps involved in establishing a JDBC connection?
Answer:
2)How can you load the drivers?
Answer:
We can use Class.forName(Driver Name)
3)What will Class.forName do while loading drivers?
Answer:
  • Class.forName method explicitly loads the driver class.
  • It is used to create instance of a database driver and register in DriverManager.
  • When the driver is loaded it is available for making connection with database based on specified driver.
4)How can you make the connection?
Answer:
By using Connection Class we can connect the database.
Example:
String url = “jdbc:mysql://localhost:3306/”;
String dbName = “sampledb”;
String username = “root”;
String password = “root”;
Connection connection = DriverManager.getConnection(url+dbName ,username, password);
5)How can you create JDBC statements?
Answer:
Statement st = con.createStatement();
st.executeUpdate(“CREATE TABLE SAMPLE_DB”);
How can you retrieve data from the ResultSet?
ResultSet rs = st.executeQuery(“SELECT * FROM SAMPLE_DB”);
while(rs.next()){
System.out.println(“SAMLE_NAME “+rs.getString(1));
}
6)What are the different types of Statements?
Answer:
1)Statement
2)Prepared Statement
7)What is the different between Statement and PreparedStatement?
Answer:
Statement:
Execute static SQL Statement and obtaining the results produced by it.
Prepared Statement:
The simple definition is “Pre Compilation”
The user created SQL is sent to the database and complied before execution.
8 ) How can you use PreparedStatement?
Answer:
String sql =”select * from sample_db where first_name=?”;
PreparedStatement pst=con.prepareStatement(sql);
pst.setString=(1,”sample_name”);
ResultSet rs = pst.executeQuery();
while (rs.next()) {
System.out.print(“Sample_dept is “+rs.getString(2));
}
9) What does setAutoCommit do?
Answer:
When the JDBC connection is successfully created that time the transaction mode is set to aoto-commit by default. When the SQL query getting executed its automattically commit the transtaction.
We can set setAutoCommit is as true or false. Example like connectionObj.setAutoCommit(false); Once the setAutoCommit is set to false you need to commit the SQL statement explicitly based on your requirement.
10) How do I retrieve warnings?
Answer:
SQLWarning object is a sub class of SQLException by using that we can get database access warnings details.
Example:
SQLWarning warnObj = stmt.getWarnings();
if warnObj != null) {
while warnObj != null) {
System.out.println(“Message: ” + warnObj.getMessage());
System.out.println(“SQLState: ” + warnObj.getSQLState());
warnObj  = warnObj .getNextWarning();
}
}
11) How do you call a stored procedure from JDBC?
Answer:
We can call Stored procedure by using callablestatement class in java.
Example:
CallableStatement stmt = conn.prepareCall(“{call USER_DETAILS (?, ?)}”);
stmt.setString(1, “samplename”);
stmt.setString(2, “samplepwd”);
stmt.execute();
Example Procedure:
CREATE OR REPLACE PROCEDURE USER_DETAILS (username IN VARCHAR2, password IN VARCHAR2) AS
BEGIN
INSERT INTO users (username, password , email) VALUES (username, password, email);
END USER_DETAILS;