at this level, it's not really about the database. It's just the name of the `dynamic segment` used to generate the routes:

> The `:param` option overrides the default resource identifier `:id` (name of the [dynamic segment](routing.html#dynamic-segments) used to generate the routes). You can access that segment from your controller using `params[<:param>]`

Also please wrap the line to 80 chars.