public static void insert(ArrayList<Double> list, String tableName, int id)
			throws FileNotFoundException, SQLException {
		// *********update
		// test if the given id is already in the table or not
		String retrievalSql = "SELECT `object` FROM `" + tableName
				+ "` where `id` = " + id;

		pst = conn.prepareStatement(retrievalSql);

		ResultSet result = (ResultSet) pst.executeQuery();
		// the result set is not empty
		if (result.next() == true) {
			// return and don't try to insert
			System.out.println("Already exists");
			return;
		}

		// ******************

		String fileName = "list.bin";
		save2(list, fileName);
		String sql = "INSERT INTO `" + tableName
				+ "` (`id`, `object`) VALUES (" + id + ",?)";

		// System.out.println(sql);

		// same the arrayList to the file
		save2(list, fileName);

		// read the object from the file
		File file = new File(fileName);
		FileInputStream fin = new FileInputStream(file);

		// STEP 4: Execute a query
		// System.out.println("Creating statement...");
		pst = conn.prepareStatement(sql);
		pst.setBinaryStream(1, fin, (int) file.length());
		pst.executeUpdate();
		// System.out.println("Insertion Done!");
	}


	public void dropTable(String tableName) throws SQLException {
		String query = "DROP table `" + tableName + "`";
		pst = conn.prepareStatement(query);
		System.out.println(query);
		if (pst.execute())
			System.out.println("Table droped successfully");
	}