public static void saveRentalBook(int rentId, int prodId){
	
	try {
		   if(conn == null || conn.isClosed()){
		    conn = DatabaseConnection.getConnection();
		   }
		  } catch (SQLException e1) {
		   // TODO Auto-generated catch block
		   e1.printStackTrace();
		  }
		
		try {
			conn.setAutoCommit(false);
			PreparedStatement stmnt = conn.prepareStatement("INSERT INTO Rentals(rental_id, product_id)"
					+  "VALUES (?, ?)");
			
			
			stmnt.setInt(1, rentId);
			stmnt.setInt(2, prodId);
			
			stmnt.execute();
			conn.commit();
			conn.setAutoCommit(true);
			
		}catch(SQLException e){
			System.out.println("insert fail book!! - " + e);
		}
		
	}