JAVA JDBC Connection

 import java.sql.*;
import java.io.*;

class dataDB
{
DataInputStream in =new DataInputStream(System.in);
Connection con;
void  connect()
{
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
con=DriverManager.getConnection("jdbc:odbc:she","scott","tiger");
System.out.println("Connected");
}
catch(Exception e)
{
System.out.println(e.getMessage());
}
}
void insert()throws IOException
{
Statement stmt;
try
{
stmt=con.createStatement();
System.out.println("How many records to insert?");
int n=Integer.parseInt(in.readLine());
for(int i=1;i<=n;i++)
{
System.out.println("Enter studid:");
int si=Integer.parseInt(in.readLine());
System.out.println("Enter stud name:");
String na=in.readLine();
System.out.println("Enter marks:");
int ma=Integer.parseInt(in.readLine());
String query="insert into studs values("+si+",'"+na+"',"+ma+")";
int rows=stmt.executeUpdate(query);
System.out.println("Rows Inserted");
con.commit();
}
}
catch(Exception e1)
{
System.out.println(e1+"Exception insertion");
}
}
void create()
{
Statement stmt;
try
{
stmt=con.createStatement();
String query="create table studs(studid number(3),name varchar2(20),marks number

(5))";
int rows=stmt.executeUpdate(query);
System.out.println("Table Created");
}
catch(SQLException e1)
{
//System.out.println(e1.getMessage());
System.out.println("Table already exists");
}
}

void update()throws IOException
{
Statement stmt;
try
{
stmt=con.createStatement();
System.out.println("Enter studid to update:");
int sid=Integer.parseInt(in.readLine());
System.out.println("Enter new marks:");
int ma=Integer.parseInt(in.readLine());
String query="update studs set marks="+ma+"where studid="+sid;
int rows=stmt.executeUpdate(query);
System.out.println(rows+"Rows Updated");
con.commit();
}
catch(Exception e1)
{
System.out.println(e1.getMessage());
}
}

void delete()throws IOException
{
Statement stmt;
try
{
stmt=con.createStatement();
System.out.println("Enter studid:");
int si=Integer.parseInt(in.readLine());
String query="delete from studs where studid="+si;
int rows=stmt.executeUpdate(query);
System.out.println(rows+"Rows Deleted");
con.commit();
}
catch(Exception e1)
{
System.out.println(e1+"Exception Deletion");
}
}

void disp()throws IOException
{
Statement stmt;
try
{
stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("select * from studs");
System.out.println("Student Details");
System.out.println("Studid      Name    Marks");
while(rs.next())
{
System.out.print(rs.getInt(1)+"           ");
System.out.print(rs.getString(2)+"           ");
System.out.print(rs.getString(3)+"         \n ");
}
}
catch(Exception e1)
{
System.out.println(e1+"Exception insertion");
}
}

public static void main(String ar[])throws IOException
{
DataInputStream in =new DataInputStream(System.in);
dataDB d=new dataDB();
int c;
System.out.println("VARIOUS OPERATION ON DATABASE");
d.connect();
do
{
System.out.println("1.create");
System.out.println("2.insert");
System.out.println("3.delete");
System.out.println("4.modify");
System.out.println("5.display");
System.out.println(" enter ur choice:");
int ch=Integer.parseInt(in.readLine());
switch(ch)
{
case 1:
d.create();
break;
case 2:
d.insert();
break;
case 3:
d.delete();
break;
case 4:
d.update();
break;
case 5:
d.disp();
break;
}
System.out.println("Enter 1->Continue");
c=Integer.parseInt(in.readLine());
}while(c==1);
}
}