diff --git a/framework/core/migrations/2018_01_11_155300_change_discussions_add_foreign_keys.php b/framework/core/migrations/2018_01_11_155300_change_discussions_add_foreign_keys.php
index 6cf2adc44..3e33b765c 100644
--- a/framework/core/migrations/2018_01_11_155300_change_discussions_add_foreign_keys.php
+++ b/framework/core/migrations/2018_01_11_155300_change_discussions_add_foreign_keys.php
@@ -37,8 +37,8 @@ return [
             $table->foreign('user_id')->references('id')->on('users')->onDelete('set null');
             $table->foreign('last_posted_user_id')->references('id')->on('users')->onDelete('set null');
             $table->foreign('hidden_user_id')->references('id')->on('users')->onDelete('set null');
-            $table->foreign('first_post_id')->references('id')->on('posts');
-            $table->foreign('last_post_id')->references('id')->on('posts');
+            $table->foreign('first_post_id')->references('id')->on('posts')->onDelete('set null');
+            $table->foreign('last_post_id')->references('id')->on('posts')->onDelete('set null');
         });
     },
 
diff --git a/framework/core/src/Discussion/Discussion.php b/framework/core/src/Discussion/Discussion.php
index cfad12d27..d9feb4b6c 100644
--- a/framework/core/src/Discussion/Discussion.php
+++ b/framework/core/src/Discussion/Discussion.php
@@ -100,21 +100,6 @@ class Discussion extends AbstractModel
 
         static::deleted(function (Discussion $discussion) {
             $discussion->raise(new Deleted($discussion));
-
-            // Delete all of the posts in the discussion. Before we delete them
-            // in a big batch query, we will loop through them and raise a
-            // PostWasDeleted event for each post.
-            $posts = $discussion->posts()->allTypes();
-
-            foreach ($posts->cursor() as $post) {
-                $discussion->raise(new PostDeleted($post));
-            }
-
-            $posts->delete();
-
-            // Delete all of the 'state' records for all of the users who have
-            // read the discussion.
-            $discussion->readers()->detach();
         });
 
         static::saving(function (Discussion $discussion) {
diff --git a/framework/core/src/Group/Group.php b/framework/core/src/Group/Group.php
index 19f1b19fd..103dd4fea 100644
--- a/framework/core/src/Group/Group.php
+++ b/framework/core/src/Group/Group.php
@@ -64,8 +64,6 @@ class Group extends AbstractModel
 
         static::deleted(function (Group $group) {
             $group->raise(new Deleted($group));
-
-            $group->permissions()->delete();
         });
     }
 
diff --git a/framework/core/src/User/User.php b/framework/core/src/User/User.php
index aad9c5f0b..4ad6e1476 100644
--- a/framework/core/src/User/User.php
+++ b/framework/core/src/User/User.php
@@ -126,22 +126,6 @@ class User extends AbstractModel
 
         static::deleted(function (User $user) {
             $user->raise(new Deleted($user));
-
-            // Delete all of the posts by the user. Before we delete them
-            // in a big batch query, we will loop through them and raise a
-            // PostWasDeleted event for each post.
-            $posts = $user->posts()->allTypes();
-
-            foreach ($posts->cursor() as $post) {
-                $user->raise(new PostDeleted($post));
-            }
-
-            $posts->delete();
-
-            $user->read()->detach();
-            $user->groups()->detach();
-            $user->accessTokens()->delete();
-            $user->notifications()->delete();
         });
 
         static::$dispatcher->fire(