diff --git a/user_guide/libraries/trackback.html b/user_guide/libraries/trackback.html
index f86ccca..4f60f5a 100644
--- a/user_guide/libraries/trackback.html
+++ b/user_guide/libraries/trackback.html
@@ -152,8 +152,8 @@
  blog_name varchar(100) NOT NULL,
  tb_date int(10) NOT NULL,
  ip_address varchar(16) NOT NULL,
- PRIMARY KEY (tb_id),
- KEY (entry_id)
+ PRIMARY KEY `tb_id` (`tb_id`),
+ KEY `entry_id` (`entry_id`)
 );</textarea>