diff --git a/ch06.ipynb b/ch06.ipynb
index f552210..7b4e8b6 100644
--- a/ch06.ipynb
+++ b/ch06.ipynb
@@ -107,7 +107,7 @@
     "    order_id = Column(Integer(), primary_key=True)\n",
     "    user_id = Column(Integer(), ForeignKey('users.user_id'))\n",
     "    shipped = Column(Boolean(), default=False)\n",
-    "    user =  relationship(\"User\", backref=backref('orders', order_by=id))\n",
+    "    user =  relationship(\"User\", backref=backref('orders', order_by=order_id))\n",
     "\n",
     "\n",
     "class LineItems(Base):\n",
@@ -145,7 +145,7 @@
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
-    "version": 2
+    "version": 2.0
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
@@ -157,4 +157,4 @@
  },
  "nbformat": 4,
  "nbformat_minor": 0
-}
+}
\ No newline at end of file