function add_quiz($title, $uid) {	
		$db = QzDB::get(); $qzid = (int) $qzid;
		$db->escape($title);
		if(!Qz_Data::is_qz($qzid)) {
			return $db->query("INSERT INTO qz_quizzes(title, uid) VALUES('$title', '$uid')");
		}
	}
	
function get_quizzes($uid) {
	$db = QzDB::get(); $uid = (int) $uid;
	return $db->get_results("SELECT qzid, title FROM qz_quizzes WHERE uid = '$uid'");
}
	
function add_question($question, $quiz_id) {
	$db = QzDB::get();
	$db->escape($question); $qzid = (int) $quiz_id;
	$db->query("INSERT INTO qz_questions(question, qzid) VALUES('$question', '$qzid')");
}
		
		function get_quiz_title($qzid) {
			$db = QzDB::get(); if(!is_int($qzid)) return;
			return $db->get_var("SELECT title FROM qz_quizzes WHERE qzid = '$qzid'");
		}
		
		function get_questions($qzid) {
			$db = QzDB::get(); if(!is_int($qzid)) return;
			return $db->get_results("SELECT qid, question FROM qz_questions WHERE qzid = '$qzid'");
		}
		
		function get_responses($qid) {
			$db = QzDB::get();
			return $db->get_results("SELECT cid, choice FROM qz_choices WHERE qid = '$qid'");
		}

function get_outcomes($qzid) {
	$db = QzDB::get(); if(!is_int($qzid)) return;
	return $db->get_results("SELECT oid, outcome, description FROM qz_outcomes WHERE qzid = '$qzid'");
}
		
		function add_choice($choice, $qid) {
			$db = QzDB::get();
			$db->escape($choice); $qid = (int) $qid;
			$db->query("INSERT INTO qz_choices(choice, qid) VALUES('$choice', '$qid')");
		}
	
	function map_outcome($cid, $oid) {
		$db = QzDB::get();
		if(!$db->get_var("SELECT COUNT(*) oid FROM qz_choice2outcome WHERE cid = '$cid'")) {
			$db->query("INSERT INTO qz_choice2outcome(cid, oid) VALUES('$cid', '$oid')");
		} else {
			$db->query("UPDATE qz_choice2outcome SET oid='$oid' WHERE cid='$cid'");
		}
	}
	
	function get_choice_outcome($cid) {
		$db = QzDB::get();
		return $db->get_var("SELECT oid FROM qz_choice2outcome WHERE cid = '$cid'");
	}
	
	function get_outcome($oid) {
		$db = QzDB::get();
		return $db->get_row("SELECT outcome, description FROM qz_outcomes WHERE oid = '$oid'");
	}
	
	function set_qz_title($title, $qzid) {
		$db = QzDB::get();
		if(!(is_numeric($qzid) && Qz_Data::is_qz($qzid))) return false;
		$db->escape($title);
		return $db->query("UPDATE qz_quizzes SET title = '$title' WHERE qzid = '$qzid'");
	}
	
	function is_qz($qzid) {
		$db = QzDB::get(); $qzid = (int) $qzid;
		return $db->get_var("SELECT COUNT(*) FROM qz_quizzes WHERE qzid = '$qzid'") != 0;
	}
}