<?php

	function confirm_query($result_set) {
		if (!$result_set) {
			die("Database query failed.");
		}
	}
	
	function find_all_subjects() {
		global $connection;
		
		$query  = "SELECT * ";
		$query .= "FROM subjects ";
		$query .= "WHERE visible = 1 ";
		$query .= "ORDER BY position ASC";
		$subject_set = mysqli_query($connection, $query);
		confirm_query($subject_set);
		return $subject_set;
	}
	
	function find_pages_for_subject($subject_id) {
		global $connection;
		
		$query  = "SELECT * ";
		$query .= "FROM pages ";
		$query .= "WHERE visible = 1 ";
		$query .= "AND subject_id = {$subject_id} ";
		$query .= "ORDER BY position ASC";
		$page_set = mysqli_query($connection, $query);
		confirm_query($page_set);
		return $page_set;
	}
	
?>