Extension:Proofread Page/pr index table

mysql> describe pr_index;
+------------+---------+------+-----+---------+-------+
| Field      | Type    | Null | Key | Default | Extra |
+------------+---------+------+-----+---------+-------+
| pr_page_id | int(11) | NO   | PRI | NULL    |       |
| pr_count   | int(11) | NO   |     | 0       |       |
| pr_q0      | int(11) | NO   |     | 0       |       |
| pr_q1      | int(11) | NO   |     | 0       |       |
| pr_q2      | int(11) | NO   |     | 0       |       |
| pr_q3      | int(11) | NO   |     | 0       |       |
| pr_q4      | int(11) | NO   |     | 0       |       |
+------------+---------+------+-----+---------+-------+