diff --git a/app/models/thread.py b/app/models/thread.py
index 418c6bc..8dfaa52 100644
--- a/app/models/thread.py
+++ b/app/models/thread.py
@@ -9,7 +9,8 @@ class Thread(db.Model):
     id = db.Column(db.Integer, primary_key=True)
 
     # Top comment
-    top_comment_id = db.Column(db.Integer, db.ForeignKey('comment.id'))
+    top_comment_id = db.Column(db.Integer,
+        db.ForeignKey('comment.id', use_alter=True))
     top_comment = db.relationship('Comment', foreign_keys=top_comment_id)
 
     # Post owning the thread, set only by Topic, Program, etc. In general, you