just learn attendance system today,
attendance system add 2 fields to the `char` table, which is `attendance_count` and `attendance_timer`
in theory, whenever player click to retrieve the item, in clif_parse_attendance_reward_request function,
-> update `char` where account_id = sd->status.account_id
EDIT: it seems if the player create a new character in the account, will mess up the `attendance_count` ...
hmm ... have to fix this to the core ...