// Program to insert, delete, update in table using PreparedStatement.
                import java.sql.*;
                import java.util.Scanner;
                
                class Database{
                    Connection c;
                    PreparedStatement s;
                    public Database(String url,String uname,String pass) throws SQLException,ClassNotFoundException{
                    Class.forName("com.mysql.cj.jdbc.Driver");
                         c=DriverManager.getConnection(url,uname,pass);
                    }
                     void insert() throws SQLException {
                    s=c.prepareStatement("insert into users values(?,?,?)");
                    s.setInt(1,13);
                    s.setString(2,"Ankush");
                    s.setString(3,"Ankush@gmail.com");
                System.out.println(s.executeUpdate() +"Row affected");
                   }
                     void delete() throws SQLException {
                        s=c.prepareStatement("delete from users where id=?");
                        s.setInt(1,8);
                System.out.println(s.executeUpdate() +"Row affected");
                        }
                
                     void update() throws SQLException {
                       s=c.prepareStatement("update users set username=? where id=?");
                       s.setString(1,"Srk");
                       s.setInt(2,1);
                       System.out.println(s.executeUpdate() +"Row affected");
                        }
                }
                class Db{
                    public static void main(String str [])throws SQLException,ClassNotFoundException,java.io.IOException{
                        String url = "jdbc:mysql://localhost:3306/mydb";
                        String username = "root";
                        String password = "";
                        Database d=new Database(url,username,password);
                        int c = 5;
                        Scanner sc=new Scanner(System.in);
                        while(c!=4){
                            System.out.println(" Press 1 for insert. \n Press 2 for delete \n Press 3 for update \n Press 4 for Exit");
                            c=sc.nextInt();
                            switch(c){
                              case 1:
                              d.insert();
                              break;
                              
                              case 2:
                              d.delete();
                              break;
                              
                              case 3:
                              d.update();
                              break;
                              case 4:
                              System.out.println("Exit Successfully");
                              break;
                              default :
                              System.out.println("Choose between 1-4");
                              break;
                            }
                        }
                    }
                }