How to use named_scope in Rails
Simple example of how to use the named_scope feature:
class Feed < ActiveRecord::Base
named_scope :active, :conditions => "(active = 1)"
named_scope :stale, :conditions => ["last_updated > ?", 30.minutes.ago.to_s(:db)]
Usage:
Feed.active # return the active feeds
Chaining is also possible:
Feed.active.stale # return the feeds that need to be updated