Rails的5個註冊嵌套屬性HAS_MANY通過與正協會+ 1

Question

我和我的小應用程序的一個問題建立的Rails 5

項目只有4個表：用戶，自定義，聯繫人，ContactCustom

這個想法是一個用戶註冊他的海關字段，當他要添加新的聯繫人時，表單應該顯示用戶登錄的海關。

我的問題是當我嘗試註冊一個新的聯繫人的海關用戶登錄後，我有一個n + 1在ContactCustom表中插入一個零寄存器，並且不捕獲我用hidd傳遞的custom_id en_field。

我的模式是這樣的：

class Custom < ApplicationRecord 
    belongs_to :user 
    belongs_to :kind 
    has_many :contact_customs 

    has_many :contacts, through: :contact_customs 
end 

class ContactCustom < ApplicationRecord 
    belongs_to :contact, optional: true 
    belongs_to :custom, optional: true 

    accepts_nested_attributes_for :custom 
end 

class Contact < ApplicationRecord 
    belongs_to :user 
    has_many :contact_customs 
    has_many :customs, through: :contact_customs 

    accepts_nested_attributes_for :contact_customs 
end 

這裏我contact_controller：

class ContactsController < ApplicationController 
    before_action :set_contact, only: [:show, :edit, :update, :destroy] 
    before_action :set_user_and_custom, only: [ :new, :create, :edit ] 

    def index 
    @contacts = Contact.all 
    end 

    def show 
    end 

    def new 
    @contact = Contact.new 
    @contact.contact_customs.build 
    end 

    def edit 
    end 

    def create 
    @contact = Contact.new(contact_params) 
    @contact.contact_customs.build 
    #binding pry 

    respond_to do |format| 
     if @contact.save 
     format.html { redirect_to @contact, notice: 'Contact was successfully created.' } 
     format.json { render :show, status: :created, location: @contact } 

     else 
     format.html { render :new } 
     format.json { render json: @contact.errors, status: :unprocessable_entity } 
     end 
    end 
    end 

    private 

    def set_contact 
     @contact = Contact.find(params[:id]) 
    end 

    def set_user_and_custom 
     @user = current_user 
     @usercustom = Custom.where(user_id: @user) 
    end 

    def contact_params 
     params.require(:contact).permit(:email, :name, :user_id, 
     contact_customs_attributes: [ :id, :value, :custom_id, custom_attributes: [] ]) 
    end 
end 

，這裏是我的形式......我想，我做了一些錯誤與每個循環：

<% @usercustom.each do |c| %> 
     <%= f.fields_for :contact_customs do |cc| %> 
     <div class="field"> 
      <%= cc.label :value, c.name %> 
      <%= cc.text_field :value %> 
     </div> 

     <%= cc.fields_for :custom do |custom| %> 
       <%= custom.text_field :id, value: c.id %> 
     <% end %> 
     <% end %> 
    <% end %> 

我不知道如何顯示有多少自定義字段沒有這個循環和我的查詢〜> @u sercustom = Custom.where（user_id：@user）正在註冊一個更多的零記錄（n + 1）。

這裏是日誌消息時，我只有一個自定義記錄提交聯繫表單自定義表：

Started POST "/contacts" for 127.0.0.1 at 2017-03-17 09:14:02 -0300 
Processing by ContactsController#create as HTML 
    Parameters: {"utf8"=>"✓", "authenticity_token"=>"nIlwxH4Ua8DjAKkMpGh8B7nxwYf6gy1Fhkdh1PaMtSANx5sB6YaOKbBUekQ4M3KP56WuHgsX31iHq2lj4+fEwA==", "contact"=>{"email"=>"test@test", "name"=>"name test", "user_id"=>"1", "contact_customs_attributes"=>{"0"=>{"value"=>"custom test"}}}, "commit"=>"Create Contact"} 
    User Load (0.6ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 1], ["LIMIT", 1]] 
    (0.2ms) BEGIN 
    User Load (0.5ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2 [["id", 1], ["LIMIT", 1]] 
    SQL (108.3ms) INSERT INTO "contacts" ("email", "name", "user_id", "created_at", "updated_at") VALUES ($1, $2, $3, $4, $5) RETURNING "id" [["email", "test@test"], ["name", "name test"], ["user_id", 1], ["created_at", 2017-03-17 12:14:02 UTC], ["updated_at", 2017-03-17 12:14:02 UTC]] 
    SQL (7.7ms) INSERT INTO "contact_customs" ("value", "contact_id", "created_at", "updated_at") VALUES ($1, $2, $3, $4) RETURNING "id" [["value", "custom test"], ["contact_id", 3], ["created_at", 2017-03-17 12:14:02 UTC], ["updated_at", 2017-03-17 12:14:02 UTC]] 
    SQL (0.6ms) INSERT INTO "contact_customs" ("contact_id", "created_at", "updated_at") VALUES ($1, $2, $3) RETURNING "id" [["contact_id", 3], ["created_at", 2017-03-17 12:14:02 UTC], ["updated_at", 2017-03-17 12:14:02 UTC]] 
    (36.5ms) COMMIT 
Redirected to http://localhost:3000/contacts/3 
Completed 302 Found in 176ms (ActiveRecord: 154.5ms) 

Answer 1

試評或刪除@contact.contact_customs.buildcreate行動。這就是你有一個N + 1 contact_customs的原因，所有字段= nil。

當你做@contact = Contact.new(contact_params)創建@contact看起來應該像這樣的：

@contact = Contact.new(:email => contact_params[:email], :name => contact_params[:name], ..etc..., :custom_attributes => contact_customs_attributes: [ :id, :value, :custom_id, custom_attributes: [] ]) 

有了，你有一個@contact對象實例化，併爲數組：

@contact.contact_customs = [ first_contact_custom => [firstvalue, secondvalue], second_contact_custom => [firstvalue, secondvalue]] 

以下：

@contact.contact_customs.build 

就像在做

@custom = Custom.new() 
@contact.customs << @custom 

這將追加在連接表contact_customs是@custom進入與各界= nil。

@contact.contact_customs = [ first_contact_custom => [firstvalue, secondvalue], second_contact_custom => [firstvalue, secondvalue], second_contact_custom => [nil, nil] ] 

因此，嘗試刪除以下行

@contact.contact_customs.build 

在你需要該行是在new活動的地方，因爲你需要實例化形式的那些字段。