import java.sql.*;
import java.io.*;

public class Test
{

public static void main(String [] args)
{
	if(args.length!=3)	{
		System.err.println("Usage: <URL> <UID> <PWD>");
		System.exit(1);
		}
	Test app=new Test();
	try	{
		app.go(args[0],args[1],args[2]);
		}
	catch(Exception e)	{
		System.err.println(e.getMessage());
		e.printStackTrace();
		}
}

private void go(String url,String uid,String pwd) throws Exception
{
	Class.forName("org.postgresql.Driver");
	Connection connection=DriverManager.getConnection(url,uid,pwd);
	connection.setAutoCommit(false);

	PreparedStatement s=connection.prepareStatement("select mykey from mytest");

	ResultSet rs=s.executeQuery();

	while(rs.next())	{
		PreparedStatement s2=connection.prepareStatement("select * from mytest where mykey=?");
		s2.setLong(1,rs.getLong(1));
		ResultSet rs2=s2.executeQuery();
		while(rs2.next())	{
			System.out.println(rs2.getLong(1) + " " + rs2.getString(2));
			}
		rs2.close();
		s.close();
		}

	rs.close();
	s.close();

	connection.commit();
	connection.close();
}

}