diff --git a/QvitterPlugin.php b/QvitterPlugin.php
index 742a1ff..771de31 100644
--- a/QvitterPlugin.php
+++ b/QvitterPlugin.php
@@ -150,6 +150,12 @@ class QvitterPlugin extends Plugin {
         return true;
     }
 
+    public function onBeforePluginCheckSchema()
+    {
+        QvitterNotification::beforeSchemaUpdate();
+        return true;
+    }
+
 	// route/reroute urls
     public function onRouterInitialized($m)
     {
diff --git a/classes/QvitterNotification.php b/classes/QvitterNotification.php
index 869827c..3c77cdd 100644
--- a/classes/QvitterNotification.php
+++ b/classes/QvitterNotification.php
@@ -19,8 +19,8 @@ class QvitterNotification extends Managed_DataObject
         return array(
             'fields' => array(
                 'id' => array('type' => 'serial', 'not null' => true),
-                'to_profile_id' => array('type' => 'int', 'description' => 'the profile being notified'),
-                'from_profile_id' => array('type' => 'int', 'description' => 'the profile that is notifying'),                
+                'to_profile_id' => array('type' => 'int', 'not null'=>true, 'description' => 'the profile being notified'),
+                'from_profile_id' => array('type' => 'int', 'not null'=>true, 'description' => 'the profile that is notifying'),
                 'ntype' => array('type' => 'varchar', 'length' => 7, 'description' => 'reply, like, mention or follow'),
                 'notice_id' => array('type' => 'int', 'description' => 'id for the reply or mention or notice being faved'),
                 'is_seen' => array('type' => 'int', 'size' => 'tiny', 'default' => 0, 'description' => 'if the notification has been seen'),                
@@ -30,7 +30,8 @@ class QvitterNotification extends Managed_DataObject
             'foreign keys' => array(
                 'qvitternotification_to_profile_id_fkey' => array('profile', array('to_profile_id' => 'id')),
                 'qvitternotification_from_profile_id_fkey' => array('profile', array('from_profile_id' => 'id')),
-                'qvitternotification_notice_id_fkey' => array('notice', array('notice_id' => 'id')),
+                // removing this because there can be rows without related notice_id
+                //'qvitternotification_notice_id_fkey' => array('notice', array('notice_id' => 'id')),
             ),
             'indexes' => array(
                 'qvitternotification_created_idx' => array('created'),
@@ -54,5 +55,43 @@ class QvitterNotification extends Managed_DataObject
         return $result;
     }
 
+    static public function beforeSchemaUpdate()
+    {
+        printfnq("\nEnsuring no NULL values for foreign keys in QvitterNotification...");
+        // Because constraints to profile and notice table assume not null, we must
+        // remove any values in these columns that are NULL (or 0), because they
+        // are invalid anyway.
+        $qn = new QvitterNotification();
+        foreach (['to_profile_id', 'from_profile_id'] as $field) {
+            $qn->whereAdd(sprintf('%s is NULL', $field), 'OR');
+            $qn->whereAdd(sprintf('%s = 0', $field), 'OR');
+        }
+        if ($qn->find()) {
+            printfnq(" removing {$qn->N} rows...");
+            while ($qn->fetch()) {
+                $qn->delete();
+            }
+        }
+        printfnq("DONE.\n");
 
+        printfnq("Ensuring no dead profile or notice IDs are stored in QvitterNotification...");
+        // We could probably build a single statement for this but I just want it done...
+        // or maybe be smart and take it directly from our defined 'foreign keys'... but oh well!
+        $constraints = ['to_profile_id'     => 'profile:id',
+                        'from_profile_id'   => 'profile:id'];
+        foreach ($constraints as $field=>$foreign) {
+            $qn = new QvitterNotification();
+            $qn->selectAdd();
+            $qn->selectAdd('qvitternotification.id');   // to avoid confusion with profile.id, also we only need the primary key
+            $qn->joinAdd([$field, $foreign], 'LEFT');
+            $qn->whereAdd(str_replace(':', '.', $foreign).' IS NULL');
+            if ($qn->find()) {
+                printfnq("\n{$field}: {$qn->N} rows...");
+                while ($qn->fetch()) {
+                    $qn->delete();
+                }
+            }
+        }
+        printfnq("DONE.\n");
+    }
 }