Question

class Property < ActiveRecord::Base
  has_many :units

  def self.default_scope
    where('active_at <= :now AND inactive_at > :now', now: Time.zone.now)
  end
end

class Unit < ActiveRecord::Base
  belongs_to :property

  def self.with_active_properties
   joins(:property)
  end
end

我正在尝试将Rails 4.0.2 default_scope与连接一起使用，但是当我调用Unit.with_active_properties时为什么我会得到以下重复的SQL？

SELECT "units".* FROM "units" INNER JOIN "properties" ON "properties"."id" = "units"."property_id" AND (active_at <= '2014-03-11 03:36:13.994068' AND inactive_at > '2014-03-11 03:36:13.994068') AND (active_at <= '2014-03-11 03:36:13.967550' AND inactive_at > '2014-03-11 03:36:13.967550')

Answer 1

经过进一步调查后，似乎这个错误是rails 4.0.x中的错误导致default_scope被调用两次的结果。我在github上发布了这个问题：

https://github.com/rails/rails/issues/14351

由于对这个问题提供了极好的帮助，所以需要得到拉里·里德的信用。

Rails加入重复的default_scope

1 个答案: