Question

有4种型号。（时尚，时尚内衣，内衣，品牌）。每个用户都可以从时尚形式中选择自己的风格。时尚形式有各种项目的下拉盒，如牛仔裤和袜子。我想重新排列项目按字母顺序在Drop框中按品牌分类，所以我使用了范围。

#### Underwear dropbox
Adidas
  adidas underwear 1
  adidas underwear 2
NIKE
  NIKE underwear 1
  NIKE underwear 2
  NIKE underwear 3

它适用于范围，但现在我收到警告，你应该包括范围。在下面的代码中，打开Fashions / new.html会给我一个警告“Please Include UnderwearNameAsc”。我研究过各种各样的东西并尝试过，但在所有使用儿童模型的情况下，我找不到解决的线索。

### Fashion model
has_one :fashion_underwear
accepts_nested_attributes_for :fashion_underwear

### FashionUnderwear model(Intermediate table)
belongs_to :fashion
belongs_to :underwear

### Underwear model
has_many :fashion_underwears
belongs_to :brand

scope :UnderwearNameAsc, -> { order(UnderwearName: :asc) }

### Brand model
has_many :underwear

has_many :UnderwearNameAsc, -> { order(UnderwearName: :asc) }, class_name: 'Underwear'

### Fashions.controller
def new
  @fashion = Fashion.new
  @fashion.build_fashion_underwear
  @brand = Brand.includes(:fashion_underwears).joins(:fashion_underwears).order(brand_name: :asc)
end

### Fashion/new.html
= simple_form_for(@fashion) do |f|
  = f.simple_fields_for :fashion_underwear do |p|
    = p.input :underwear_id, collection: @brand, as: :grouped_select, group_method: :UnderwearNameAsc, group_label_method: :brand_name, label_method: :UnderwearName

Answer 1

子弹指出你有n+1 query problem。它建议您通过添加includes来解决问题，从而更改Brand模型中的has_many关联，如下所示：

has_many :UnderwearNameAsc, -> { includes(:underwear).order(UnderwearName: :asc) }, class_name: 'Underwear'

当你在这里时，你真的应该在standard Ruby style中将范围和方法的名称更改为snake_case。否则Ruby会认为这些方法和范围是常量。

此外，我只会为您返回的内容命名范围，而不是该模型上的单个属性。最后，我要单独使用一个作用域，并在需要对资源进行排序时显式调用它。

has_many :underwear # Or has_many :underwears if Rails interprets the plural that way
scope :sorted, -> { includes(:underwear).order(underwear: {name: :asc} }

然后你可以这样做：

Brand.all # Returns unsorted records
Brand.all.sorted # Returns records sorted by underwear.name

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