Rails 3.1.1 : MySQL : composite keys

how can I rewrite the migration script to generate the composite keys
from an existing table

......
  PRIMARY KEY (`id`),
  KEY `by_scheduled_sent_released`
(`scheduled_at`,`sent_at`,`released_at`),
  KEY `by_account_uidl` (`account_id`,`unique_id`),
  KEY `by_account_message` (`account_id`,`message_id`),
  KEY `by_released_sent_received`
(`released_at`,`sent_at`,`received_at`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

is it true that Rails doesn't support it ?

thanks fy feedback

Kad Kerforn wrote in post #1034598:

how can I rewrite the migration script to generate the composite keys
from an existing table

......
  PRIMARY KEY (`id`),
  KEY `by_scheduled_sent_released`
(`scheduled_at`,`sent_at`,`released_at`),
  KEY `by_account_uidl` (`account_id`,`unique_id`),
  KEY `by_account_message` (`account_id`,`message_id`),
  KEY `by_released_sent_received`
(`released_at`,`sent_at`,`received_at`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

is it true that Rails doesn't support it ?

It is true that ActiveRecord does not support composite keys, not
without help. Thankfully, there is a gem for that:

https://github.com/drnic/composite_primary_keys

Note: I have not used this gem and have no opinion about it one way or
the other. It is just the first one to come up in the Github search.

Thanks a lot Walter .. I'll have a look at it