public void addPhenomenon(String phenomenon_id,
			String phenomenon_description, String unit, String valuetype) {
		// only add phenomenon to database if not yet added
		if (!this.isPhenomenonInDatabase(phenomenon_id)) {

			String query = "INSERT INTO phenomenon VALUES ('" + phenomenon_id
					+ "', '" + phenomenon_description + "', '" + unit + "','"
					+ valuetype + "');";
			try {
				Statement stmt = con.createStatement();
				stmt.execute(query);
			} catch (SQLException e) {
				logger.warn("Invalid query: "+ query, e);
				e.printStackTrace();
			}
		}
	}