Question

我正在尝试将一个项目从Rails 3更新到Rails 4.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，它会在Rails 3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更新了这样的：

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

它在order子句中添加代码，这使得PostgreSQL通过错误。我认为这是因为范围，但我无法弄清楚如何获得ORDER BY代码。

感谢任何帮助，谢谢！

Answer 1

Rails社区帮助我找到了解决方案。

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

  def tint_types
    super.reorder(nil).order(:width => :asc)
  end
end

有关详细信息，请参阅https://github.com/rails/rails/issues/12719。

Answer 2

将tint_types关联更改为

has_many :tint_types, -> { reorder('value').uniq }, :through => :tint_codes

从rails 3升级到rails 4时，has_many关联的顺序错误

2 个答案: