mysql> describe wbs_propertypairs;
+-------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+---------------------+------+-----+---------+----------------+
| row_id | bigint(20) unsigned | NO | PRI | NULL | auto_increment |
| pid1 | int(10) unsigned | NO | MUL | NULL | |
| qid1 | int(10) unsigned | YES | | NULL | |
| pid2 | int(10) unsigned | NO | | NULL | |
| count | int(10) unsigned | NO | | NULL | |
| probability | float | NO | | NULL | |
| context | varbinary(32) | NO | | NULL | |
+-------------+---------------------+------+-----+---------+----------------+