read the following program and describe what the program does. write comments in

Question

read the following program and describe what the program does. write comments in the program listing to follow "//".

import java.io.*;

import java.sql.*;

public class Example { public static void main (String args []) throw SQL Exception, IOException {

try {

// //

Class.forName("oracle.jdbc.driver.OracleDriver");

}

// //

catch (ClassNotFoundException ex){

System.out.println("Driver could not be loaded");

return; }

// //

String url= jdbc:oracle:www.bookstore.com:3083";

// //

Connection con;

try {

// //

con= DriveManager.getConnection(url, userId, password);

// //

String sqlQuery = "SELECT isbn, title FROM Books WHERE publisher = 'MIT Press'"'

//

//

PreparedStatement stmt = con.prepareStatement(sqlQuery);

//

//

ResultSet rs = stmt.executeQuery(sqlQuery);

String isbn, title;

System.out.println("isbn, title");

//

//

while(rs.next()) {

isbn = rs.getString(1);

title = rs.getString("TITLE");

System.out.println(isbn + " " + title);

}

}

//

catch(SQLException ex){

System.out.println("ex.getMessage());

}

}

}

Explanation / Answer

import java.io.*;
import java.sql.*;
public class Example
{
   public static void main (String args []) throw SQL Exception, IOException
   {
try {
// this will returns the Class object of the name passed in the parameter
   Class.forName("oracle.jdbc.driver.OracleDriver");
}
// this will be executed if the class object is not returned
   catch (ClassNotFoundException ex)
   {
   System.out.println("Driver could not be loaded");
   return;
   }
   // // the below line will declare the string named with url which will tell the compiler the path of database
   String url= jdbc:oracle:www.bookstore.com:3083";
  
   // // the below line will declare the object of type connection which is use to make a conection with databas
   Connection con;
   try {
  
   // //the below line will create a connection by passing the url by using the userId and password
   con= DriveManager.getConnection(url, userId, password);
  
   // // this line will declare the SQL query which will return a table from the database
   String sqlQuery = "SELECT isbn, title FROM Books WHERE publisher = 'MIT Press'"'
  
// the below line will be used to execute the query which is passed in the parameter
   PreparedStatement stmt = con.prepareStatement(sqlQuery);
  
   // The ResultSet class object is use to execute the query and will store the result in rs named object`
   ResultSet rs = stmt.executeQuery(sqlQuery);
   String isbn, title;
   System.out.println("isbn, title");

   //the below code will loop over the object rs until the rs will have values
   while(rs.next()) {
   isbn = rs.getString(1);
   title = rs.getString("TITLE");
   System.out.println(isbn + " " + title);
   }
   }
   //   this will be exectued in case if any of the above lines throw any exception
   catch(SQLException ex){
   System.out.println("ex.getMessage());
   }
   }
   }

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