Changing database entry only by entering a password

Question

I'm trying to have a page that displays a persons data and each person is assigned to an agent. I want the field where the persons agent can be changed to have a password.
i.e if some other agent tries to change the persons agent they have to fill in the original agents password, so that only the agent assigned can change the assigned agent to a new one.
I hope that makes some sense some example code would be great.
Thanks Paul :)

Answer 1

THANK YOU SO MUCH!
It is a client-side setup. I'm afraid though i have a few more questions. I read your post a few times to gleam all i could.
I understand most of it, I'm just unsure of how to "connect to database to get the password corresponding to this user name". You said to use an int if i wanted different access levels the problem is that i need different access levels and each 'agent'/'user name' to only be able to edit the properties they have added to the database. how could i achieve this?
this is what i've come up with, it work but when i press login i get two errors:
* There is an error with your username, please fill it in exactly as assigned.
* You are not logged in, or your username does not exist or your password is not correct.
import javax.swing.event.*;
import javax.swing.*;
import java.sql.*;
import java.awt.*;
import java.util.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener; // used for ActionListener
public class Login extends JFrame implements ActionListener
    private JComboBox cmbNames;
    private JLabel lblUsrName = new JLabel ("User name");
    private JLabel lblPass = new JLabel ("Password");
    private JTextField txtUsrName = new JTextField ();
    private JTextField txtPass = new JTextField ();
    private JPasswordField pasPass = new JPasswordField ();
    private JButton btnLogin = new JButton ("Login");
    private JButton btnCancel = new JButton ("Cancel");
    private boolean loggedIn = false; //or you can have an int here to show access level with 0=notlogged, 1=user, 2=admin for example
    private Connection conn = null;
    private Container c;
    public Login ()
        super ("Agent Login Panel");
        setDefaultCloseOperation (EXIT_ON_CLOSE);
        setSize (235, 160);
        setResizable (false);
        show ();
        Dimension dim = Toolkit.getDefaultToolkit ().getScreenSize ();
        int w = getSize ().width;
        int h = getSize ().height;
        int x = (dim.width - w) / 2;
        int y = (dim.height - h) / 2;
        setLocation (x, y);
        c = getContentPane ();
        c.setLayout (null);
        connectToDB ();
        populateFrame ();
        show ();
    public void connectToDB ()
        try
            Class.forName ("sun.jdbc.odbc.JdbcOdbcDriver");
        catch (ClassNotFoundException c)
            JOptionPane.showMessageDialog (this, "Error loading driver", "Error", JOptionPane.ERROR_MESSAGE);
        try
            conn = DriverManager.getConnection ("jdbc:odbc:BASE");
        catch (Exception e)
            JOptionPane.showMessageDialog (this, "Error with connect", "Error", JOptionPane.ERROR_MESSAGE);
    public void dispose ()
        super.dispose ();
        try
            conn.close ();
        catch (SQLException e)
            JOptionPane.showMessageDialog (this, "Error with Disconnect", "Error", JOptionPane.ERROR_MESSAGE);
    public void populateFrame ()
        c.add (lblUsrName); // horz vert
        lblUsrName.setBounds (30, 20, 75, 30);
        c.add (lblPass); //       width height
        lblPass.setBounds (30, 50, 75, 30);
        c.add (txtUsrName);
        txtUsrName.setBounds (105, 20, 100, 30);
        c.add (pasPass);
        pasPass.setBounds (105, 50, 100, 30);
        c.add (btnLogin);
        btnLogin.addActionListener (this);
        btnLogin.setBounds (20, 85, 95, 30);
        c.add (btnCancel);
        btnCancel.addActionListener (this);
        btnCancel.setBounds (115, 85, 95, 30);
    public void actionPerformed (ActionEvent e)
        if (e.getSource () == btnLogin) //or the "OK" buton of the loginDialog
            try
                Statement s = conn.createStatement ();
                ResultSet rs = s.executeQuery ("SELECT Password FROM tblAgents WHERE UserName = " + txtUsrName.getText ()); //ORDER BY used to find names easier
                txtPass.setText (rs.getString ("Password"));
                rs.close ();
                s.close ();
            catch (SQLException se)
                JOptionPane.showMessageDialog (this, "There is an error woth your username, please fill it in exactly as assigned.", "Error", JOptionPane.ERROR_MESSAGE);
            //verify user
            String username = txtUsrName.getText ();
            String correctPassword = txtUsrName.getText (); //the correct pass now stored as 'correctPassword'
            if (pasPass.getText ().equals (correctPassword))
                loggedIn = true;
            else
                JOptionPane.showMessageDialog (this, "You are not logged in, or your username does not exist or your password is not correct.", "Error", JOptionPane.ERROR_MESSAGE);
            //Finally checks if logged in and open new window
            if (loggedIn)
            {                new MainHome ();            }
        else if (e.getSource () == btnCancel)
            dispose ();
        }    } }