search for: possible_key

I am pretty much new at this ROR game and had what I think to be a simple question. I have a set of Sponsors that I would like to be able to select one at random and display in the my html. I have already set up the DB, scaffolded, set index controller and all is working smoothly. I know that I can display them all by doing <% for sponsor in @sponsors %> <%= sponsor.name %>

I am trying to speed up some DB operations and perhaps have gone overboard with indexes. Does MySQL usually use only one index per query and simply match keys on the results of the indexed first part? For example: DELETE FROM tokens WHERE 6813946236211560448 <= fnv AND fnv < 6818449835838930944 AND updated_at<''2010-06-20 14:08:55'' AND occurrences=0; If I understand

...k Load (0.0ms)←[0m ←[1mSELECT `tasks`.* FROM `tasks` ←[0m ←[1m←[35mEXPLAIN (30.0ms)←[0m EXPLAIN SELECT `tasks`.* FROM `tasks` EXPLAIN for: SELECT `tasks`.* FROM `tasks` +----+-------------+-------+------+---------------+------+---------+------+------+-------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+------+---------------+------+---------+------+------+-------+ | 1 | SIMPLE | tasks | ALL | NULL | NULL | NULL | NULL | 2 | | +----+-------------+-------+------+---------------+------+---------+------+------...