private void insertDemoProducts(){
        try {
            db = new DataBase();
            Random randomNumbers;
            int n=0;
            
            for(int i=0;i<=20;i++){
                con = db.getConnection();
                statement = con.createStatement();
                randomNumbers = new Random();
                int number = 190 + randomNumbers.nextInt( 300 - 200 + 1 );
                int av = 20 + randomNumbers.nextInt( 50 - 20 + 1 );
                String quality;
                if(av%2==0){
                    quality="Good";
                }else{
                    quality="Normal";
                }
                
                String query = "INSERT INTO  `products` (`product_name` ,  `brand` ,  `model` ,  `quality` ,  `price` ,  `available` ) \n" +
                    "VALUES (\n" +
                    "'Monitor',  'Samsung',  'Md-d"+i+"-4df',  '"+quality+"',  '"+number+"',  '"+av+"'\n" +
                    ");";
                statement.executeUpdate(query);

                
            }
            
            for(int i=0;i<=10;i++){
                con = db.getConnection();
                statement = con.createStatement();
                randomNumbers = new Random();
                int number = 100 + randomNumbers.nextInt( 200 - 150 + 1 );
                int av = 20 + randomNumbers.nextInt( 50 - 20 + 1 );
                String quality;
                if(av%2==0){
                    quality="Good";
                }else{
                    quality="Normal";
                }
                
                String query = "INSERT INTO  `products` (`product_name` ,  `brand` ,  `model` ,  `quality` ,  `price` ,  `available` ) \n" +
                    "VALUES (\n" +
                    "'Printer',  'Samsung',  'Md-dow-a"+i+"',  '"+quality+"',  '"+number+"',  '"+av+"'\n" +
                    ");";
                statement.executeUpdate(query);
                
            }
            
            for(int i=0;i<=18;i++){
                con = db.getConnection();
                statement = con.createStatement();
                randomNumbers = new Random();
                int number = 100 + randomNumbers.nextInt( 200 - 150 + 1 );
                int av = 20 + randomNumbers.nextInt( 50 - 20 + 1 );
                String quality;
                if(av%2==0){
                    quality="Good";
                }else{
                    quality="Normal";
                }
                
                String query = "INSERT INTO  `products` (`product_name` ,  `brand` ,  `model` ,  `quality` ,  `price` ,  `available` ) \n" +
                    "VALUES (\n" +
                    "'Printer',  'LG',  'b-"+i+"',  '"+quality+"',  '"+number+"',  '"+av+"'\n" +
                    ");";
                statement.executeUpdate(query);
                n++;
                
            }
            
            for(int i=0;i<=22;i++){
                con = db.getConnection();
                statement = con.createStatement();
                randomNumbers = new Random();
                int number = 100 + randomNumbers.nextInt( 200 - 150 + 1 );
                int av = 20 + randomNumbers.nextInt( 50 - 20 + 1 );
                String quality;
                if(av%2==0){
                    quality="Good";
                }else{
                    quality="Normal";
                }
                
                String query = "INSERT INTO  `products` (`product_name` ,  `brand` ,  `model` ,  `quality` ,  `price` ,  `available` ) \n" +
                    "VALUES (\n" +
                    "'NoteBook',  'Samsung',  'bm-"+i+"20',  '"+quality+"',  '"+number+"',  '"+av+"'\n" +
                    ");";
                statement.executeUpdate(query);

                n++;
                
            }

            con.close();
            
            
        } catch (Exception ex) {
            Logger.getLogger(InitializationForm.class.getName()).log(Level.SEVERE, null, ex);
        }
    }