从rails 3升级到rails 4时has_many关联的顺序错误

我正在尝试将一个项目从Rails3更新到Rails4。在Rails 3中,我正在做:

class Sale < ActiveRecord::Base
  has_many :windows, :dependent => :destroy
  has_many :tint_codes, :through => :windows, :uniq => true, :order => 'code ASC'
  has_many :tint_types, :through => :tint_codes, :uniq => true, :order => 'value ASC'
end

当我调用sale.tint_types时,它在Rails3中执行以下查询:

SELECT DISTINCT "tint_types".* FROM "tint_types" INNER JOIN "tint_codes" ON "tint_types"."id" = "tint_codes"."tint_type_id" INNER JOIN "windows" ON "tint_codes"."id" = "windows"."tint_code_id" WHERE "windows"."sale_id" = 2 ORDER BY value ASC

我为Rails 4更新了它,如下所示:

class Sale < ActiveRecord::Base
  has_many :windows, :dependent => :destroy
  has_many :tint_codes, -> { order('code').uniq }, :through => :windows
  has_many :tint_types, -> { order('value').uniq }, :through => :tint_codes
end

查询更改为:

SELECT DISTINCT "tint_types".* FROM "tint_types" INNER JOIN "tint_codes" ON "tint_types"."id" = "tint_codes"."tint_type_id" INNER JOIN "windows" ON "tint_codes"."id" = "windows"."tint_code_id" WHERE "windows"."sale_id" = $1  ORDER BY value, code

它增加了 密码 在order子句中,这使得PostgreSQL通过了一个错误。我认为这是因为作用域的原因,但我不知道如何获得ORDERBY代码。

感谢任何帮助, 谢谢