named_scope
比如很多查询都使用一个相同的conditions的化那么可以如下定义一个named_scope
named_scope :today, :conditions => ['created_at = ?', 0.days.ago]
还可以加参数
named_scope:bydate, lambda { |*args| {:conditions => ['created_at = ?', (args.first || 0.days.ago)]}}
使用方法
Post.today
Post.bydate(2.days.ago)