user_bids(*user_id, *item_end_date, *bid_id, *item_id)
bids_with_user(*item_id, *bid_id, *user_id, item_end_date)
bids_by_date(*item_id, *bid_date, *bid_id, *user_id, user_nickname, bid_qty, bid_value)

user_bids item_id -> item_end_date
user_bids bid_id -> user_id, item_id
bids_with_user item_id -> item_end_date
bids_with_user bid_id -> user_id, item_id
bids_by_date bid_id -> bid_date, bid_qty, bid_value, user_id, item_id
bids_by_date user_id -> user_nickname

user_bids item_id, item_end_date, bid_id, user_id == bids_with_user ...
user_bids item_id, bid_id, user_id == bids_by_date ...
bids_with_user item_id, bid_id, user_id == bids_by_date ...