diff --git a/gen.php b/gen.php
index 104a34f..4f77c77 100644
--- a/gen.php
+++ b/gen.php
@@ -1,8 +1,8 @@
 <?php
 
-$type = $_POST['type'];
-$def = $_POST['def'];
-$private = $_POST['private'] ? 1 : 0;
+$type = isset($_POST['type']) ? $_POST['type'] : NULL;
+$def = isset($_POST['def']) ? $_POST['def'] : NULL;
+$private = isset($_POST['private']) ? ($_POST['private'] ? 1 : 0) : 0;
 
 if ($type != 'graph' && $type != 'digraph')
 	die("Nuh-uh. Use one of the checkboxes.");
@@ -20,6 +20,7 @@ function get_one($q)
 {
 	$res = mysql_query($q);
 	if (!$res) die("Failed to get stuff from database. Sorry!");
+	if (mysql_num_rows($res) == 0) return NULL;
 	return mysql_result($res, 0);
 }
 function id_shorten($id)
diff --git a/get.php b/get.php
index a145d08..fd6ba39 100644
--- a/get.php
+++ b/get.php
@@ -16,7 +16,7 @@ function id_lengthen($id)
 	return $res;
 }
 
-$id = $_GET['id'];
+$id = isset($_GET['id']) ? $_GET['id'] : NULL;
 if (!$id) die("No ID given.");
 if (strlen($id) == 40)
 	$q = "graph_code = '".mysql_real_escape_string($id)."'";
diff --git a/index.php b/index.php
index c53307d..0f8b3e0 100644
--- a/index.php
+++ b/index.php
@@ -17,7 +17,7 @@
 <p>Definition (without the surrounding <code>[di]graph {}</code> thing): (<a
 href="http://en.wikipedia.org/wiki/DOT_language">syntax</a>, <a
 href="index.php?example=1">example</a>)<br>
-<textarea name="def" rows="20" cols="50"><?php if ($_GET['example']):
+<textarea name="def" rows="20" cols="50"><?php if (isset($_GET['example']) && $_GET['example']):
 ?>Sleep -&gt; Work [label="zombie"]
 Work -&gt; TV [label="zombie"]
 TV -&gt; Sleep [label="zombie"]