diff --git a/sites/all/modules/custom/contrib/anon_comment/anon_comment.install b/sites/all/modules/custom/contrib/anon_comment/anon_comment.install
index 011fa62..a251878 100644
--- a/sites/all/modules/custom/contrib/anon_comment/anon_comment.install
+++ b/sites/all/modules/custom/contrib/anon_comment/anon_comment.install
@@ -25,10 +25,17 @@ function anon_comment_schema() {
         'not null' => TRUE
         )
       ),
-    'primary_key' => array('cid', 'uid'),
+    'primary key' => array('cid', 'uid'),
     'indexes' => array(
       'authors' => array('uid')
     )
   );
   return $schema;
-}
\ No newline at end of file
+}
+
+/**
+ * Fix primary key.
+ */
+function anon_comment_update_7001() {
+  db_add_primary_key('anon_comment_authors', array('cid', 'uid'));
+}