Schema

mysql> describe openbadges_assertion;
+--------------------+------------------+------+-----+---------+----------------+
| Field              | Type             | Null | Key | Default | Extra          |
+--------------------+------------------+------+-----+---------+----------------+
| obl_id             | int(11)          | NO   | PRI | NULL    | auto_increment |
| obl_timestamp      | binary(14)       | NO   | MUL | NULL    |                |
| obl_receiver       | int(10) unsigned | NO   | MUL | NULL    |                |
| obl_badge_id       | int(11)          | NO   |     | NULL    |                |
| obl_badge_evidence | varchar(255)     | YES  |     | NULL    |                |
| obl_expiration     | binary(14)       | YES  |     | NULL    |                |
+--------------------+------------------+------+-----+---------+----------------+
6 rows in set (0.01 sec)