Effective usage of :finder_sql in has_many associations in Rails

Question

In ActiveRecord models you can specify custom SQL-request for has_many associations. For example,

class User < AciveRecord::Base
  has_many :events, :finder_sql => 'SELECT something complex'
end

While user.events returns what I need, the number of records returned can be huge, so I need to have a way to pass parameters for LIMIT. Is there such a way?

The only solution I found yet is to create events(start, count) method instead and call Event.find_by_sql in it.

In case finder_sql doesn't allow doing this, what is it useful for?

Answer 1

I used named_scope for this sort of thing. Check out Railscast #108 for a good tutorial.