Aim: Write a program by using JDBC to execute an update query using PreparedStatement and display the results.

Theory:

PreparedStatement interface:

The PreparedStatement interface is a subinterface of Statement. It is used to execute parameterized query.

Let's see the example of parameterized query:

String sql="insert into emp values(?,?,?)";

As you can see, we are passing parameter (?) for the values. Its value will be set by calling the setter methods of PreparedStatement.

Improves performance: The performance of the application will be faster if you use PreparedStatement interface because query is compiled only once.

To get the instance of PreparedStatement:

The prepareStatement() method of Connection interface is used to return the object of PreparedStatement. Syntax:

1. public PreparedStatement prepareStatement(String query)throws SQLException{}

Methods of PreparedStatement interface:

The important methods of PreparedStatement interface are given below:

Method	Description
public void setInt(int paramIndex, int value)	sets the integer value to the given parameter index.
public void setString(int paramIndex, String value)	sets the String value to the given parameter index.
public void setFloat(int paramIndex, float value)	sets the float value to the given parameter index.
public void setDouble(int paramIndex, double value)	sets the double value to the given parameter index.
public int executeUpdate()	executes the query. It is used for create, drop, insert, update, delete etc.
public ResultSet executeQuery()	executes the select query. It returns an instance of ResultSet.

Program:

import java.sql.*;
import java.util.*;
class Update1
{
public static void main(String args[])
{
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection c =DriverManager.getConnection("jdbc:odbc:xe","system","swapna");
PreparedStatement ps=c.prepareStatement("update student36 set name='diya shirley' where num=11");
System.out.println("\n\nUpdated\n\n");
ps.executeUpdate();

Statement st= c.createStatement();
ResultSet r1=st.executeQuery("select *from student36");
while(r1.next())
{
int x = r1.getInt("NUM");
String y= r1.getString("NAME");
System.out.println(x+"\t "+y);
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}