JAVA: Database Connection with Java Program

Programs Related to Database Connection with Java.

Here Is My database:

Here,Logical name is StudentDetails

Source Code:

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import sun.jdbc.odbc.*;
/*
<applet code="DataBaseDemo" width=550 height=550>
</applet>
*/

public class DataBaseDemo extends Applet implements ActionListener
{
Statement stmt;
String s="Wel Come.";
Label Lname,LRollNo;
Button Show,Insert,Update,Del;
TextField txtName,txtRoll;
public void init()
{
Lname=new Label("name");
LRollNo=new Label("roll no");
Show=new Button("show");
Insert=new Button("insert");
Update=new Button("update");
Del=new Button("delete");
txtName=new TextField(12);
txtRoll=new TextField(8);

add(Lname);
add(txtName);
add(LRollNo);
add(txtRoll);
add(Show);
add(Insert);
add(Update);
add(Del);

Show.addActionListener(this);
Insert.addActionListener(this);
Update.addActionListener(this);
Del.addActionListener(this);


try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn= DriverManager.getConnection("jdbc:odbc:StudentDetails","","");
stmt = conn.createStatement();
}
catch(Exception e)
{}

}
public void showData(String msg)
{
try
   {
   String sql = "select * from StudentDetail ";
   ResultSet rs = stmt.executeQuery(sql);
   s=msg;
   while(rs.next())
   {
   s = s+ rs.getString(1)+" ";
   s =s+ rs.getString(2)+" ";
   }
   }
   catch(Exception e)
{}
}
public void actionPerformed(ActionEvent ae)
{
String m=ae.getActionCommand();
if(m.equals("show"))
      {
showData("Name and Roll Number Stored in database are.. ");
    }
else if(m.equals("insert"))
{
      try
      {
String name=txtName.getText();
   String Roll=txtRoll.getText();
   String sql = "INSERT into StudentDetail VALUES ('"+name+"','"+Roll+"')";

   int num= stmt.executeUpdate(sql);
   showData("Inserted.New Data : ");
      }
      catch(Exception e)
{}
}
else if(m.equals("delete"))
{
try
{
String name=txtName.getText();
String Roll=txtRoll.getText();
String sql = "DELETE from StudentDetail WHERE StuRoll='"+Roll+"'";
int num= stmt.executeUpdate(sql);
showData("Deleted.New Data : ");
}
catch(Exception e)
{
}
}
else
{
   try
     {
   String name=txtName.getText();
String Roll=txtRoll.getText();
String sql = "UPDATE StudentDetail set StuName='"+name+"' WHERE StuRoll='"+Roll+"'";

int num= stmt.executeUpdate(sql);
   showData("Updated.New Data : ");
}
catch(Exception e)
{
}
}
repaint();
}

public void paint(Graphics g)
{
g.setColor(Color.red);
g.drawString(s,10,70);
}
}