public void deleteObservationAndQuality(String feature_id){
		//first delete the quality entries
		String query = "DELETE FROM quality WHERE observation_id IN (SELECT observation_id FROM quality NATURAL INNER JOIN observation NATURAL INNER JOIN feature_of_interest WHERE feature_of_interest_id='"+feature_id+"');";
		try {
			Statement stmt = con.createStatement();
			stmt.execute(query);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		
		//delete observation entries
		query = "DELETE FROM observation WHERE feature_of_interest_id='"+feature_id+"';";
		try {
			Statement stmt = con.createStatement();
			stmt.execute(query);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		
	}