just went to phpbb site, and look at their Medal System Mod:
http://www.phpbb.com/phpBB/viewtopic.php?t=148362
Didnt install that mod and test it, but the database structure looks much better.
They add medals (awards) by issue_id, with fields medal_id, user_id, issue_reason, issue_time, which allow you to limit the size of database, without adding a whole bunch of empty awards for all users (like the current one does)
I know that Arial is paying for the hack to be made, but ... just wondering if anyone can share the idea
https://vborg.vbsupport.ru/showthread.php?p=621249