How to write a select box and id should be stored in database?

You haven't clarified your query properly. Anyways, here is an example of inserting the id value into the database according to the name selected from the drop down.

import java.sql.*;
import java.awt.*;
import java.util.*;
import javax.swing.*;
import java.awt.event.*;
class ComboBox{

    public static void main(String[] args) throws Exception{
        JFrame f=new JFrame();
        f.setLayout(null);
        JLabel lab=new JLabel("Select Name:");
        final JComboBox combo=new JComboBox();
        combo.addItem("George");
        combo.addItem("Maria");
        combo.addItem("John");
        combo.addItem("Jennifer");
        combo.addItem("Kate");

        ActionListener actionListener = new ActionListener(){
        public void actionPerformed(ActionEvent actionEvent) {
        ItemSelectable is = (ItemSelectable)actionEvent.getSource();
        String name=selectedString(is);
        try{
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root" );
        Statement st=conn.createStatement();
        st.executeUpdate("update data1 set id=60 where name='"+name+"'");
        System.out.println("Inserted");
        }
        catch(Exception E){}
        }
       };
       combo.addActionListener(actionListener);
       combo.setEditable(true);
       lab.setBounds(20,20,100,20);
       combo.setBounds(120,20,80,20);
       f.add(lab);
       f.add(combo);
       f.setVisible(true);
       f.setSize(300,120);
    }
    static private String selectedString(ItemSelectable is) {
    Object selected[] = is.getSelectedObjects();
    return ((selected.length == 0) ? "null" : (String)selected[0]);
  } 
}

Here is another example that simply insert the selected combobox value and id into the database.

import java.sql.*;
import java.awt.*;
import java.util.*;
import javax.swing.*;
import java.awt.event.*;
class ComboBox{

    public static void main(String[] args) throws Exception{
        JFrame f=new JFrame();
        f.setLayout(null);
        JLabel lab=new JLabel("Select Name:");
        final JComboBox combo=new JComboBox();
        combo.addItem("George");
        combo.addItem("Maria");
        combo.addItem("John");
        combo.addItem("Jennifer");
        combo.addItem("Kate");

        ActionListener actionListener = new ActionListener(){
        public void actionPerformed(ActionEvent actionEvent) {
        ItemSelectable is = (ItemSelectable)actionEvent.getSource();
        String name=selectedString(is);
        System.out.println(name);
        try{
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root" );
        Statement st=conn.createStatement();


        st.executeUpdate("insert into data1(id,name) values(60,'"+name+"')");
        System.out.println("Inserted");
        }
        catch(Exception e){
        System.out.println(e);
        }
        }
       };
       combo.addActionListener(actionListener);
       lab.setBounds(20,20,100,20);
       combo.setBounds(120,20,80,20);
       f.add(lab);
       f.add(combo);
       f.setVisible(true);
       f.setSize(300,120);
    }
    static private String selectedString(ItemSelectable is) {
    Object selected[] = is.getSelectedObjects();
    return ((selected.length == 0) ? "null" : (String)selected[0]);
  } 
}