ActiveModel::MissingAttributeError（无法写入未知属性`flights_count`）：

Question

我正在做一些重构，我已经看过这个项目一段时间了，从我上次回忆的情况来看，它确实有效。但问题是，我正在尝试创建一个航班，但在尝试时我不断收到“ActiveModel::MissingAttributeError (can't write unknown attribute flights_count):”创建一个新的航班。

就我的模型而言：

我的飞行，飞行员模型

class Flight < ActiveRecord::Base
    has_many :passengers
    belongs_to :destination
    belongs_to :pilot, counter_cache: true
    accepts_nested_attributes_for :passengers
    belongs_to :user, class_name: "Flight" ,optional: true 
    validates_presence_of :flight_number
    validates :flight_number, uniqueness: true
    scope :order_by_flight_international, -> { order(flight_number: :asc).where("LENGTH(flight_number) > 3") }
    scope :order_by_flight_domestic, -> { order(flight_number: :asc).where("LENGTH(flight_number) <= 2 ") }
    

    def dest_name=(name)
        
        self.destination = Destination.find_or_create_by(name: name)
    end

    def dest_name
        
        self.destination ? self.destination.name : nil
    end

    def pilot_name=(name)
        self.pilot = Pilot.find_or_create_by(name: name)
    end

    def pilot_name
        
        self.pilot ? self.pilot.name : nil
    end

    

end


class Pilot < ActiveRecord::Base
    belongs_to :user, optional: true
    has_many :flights
    has_many :destinations, through: :flights
    
    validates_presence_of :name, :rank
    validates :name, uniqueness: true
    scope :top_pilot, -> { order(flight_count: :desc).limit(1)}
   
end

编辑 飞行控制器

class FlightsController < ApplicationController
    before_action :verified_user
    layout 'flightlayout'

    def index
        @flights = Flight.order_by_flight_international
        @dom_flights = Flight.order_by_flight_domestic
    end

    
    
    def new
        @flight = Flight.new
        10.times {@flight.passengers.build}
       
    end

    def create
        @flight = Flight.new(flight_params)
        # byebug
        if @flight.save!
  
            redirect_to flight_path(current_user,@flight)
        else
            flash.now[:danger] = 'Flight Number, Destination, and Pilot have to be selected at least'
            render :new
  
           
        end
    end
  private

    def flight_params
        params.require(:flight).permit(:flight_number,:date_of_flight, :flight_time, :flight_id, :destination_id, :pilot_id, :pilot_id =>[], :destination_id =>[], passengers_attributes:[:id, :name])
    end
    
    
end

编辑 航班、试点模式

create_table "flights", force: :cascade do |t|
    t.integer "pilot_id"
    t.integer "destination_id"
    t.string "flight_number"
    t.string "date_of_flight"
    t.string "flight_time"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "pilots", force: :cascade do |t|
    t.string "name"
    t.string "rank"
    t.integer "user_id"
    t.integer "flight_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.integer "flight_count", default: 0
  end

正如我上次在这个项目上工作时所说的，一切正常，但我面临这个问题。这次我做错了什么。

Answer 1

您在Flight 模型中为pilots 定义了一个counter_cache。当您只使用counter_cache: true 定义它时，ActiveRecord 将在您的pilots 表中查找名为flights_count 的列，但我看到您已将其命名为flight_count。您可以将列重命名为 flights_count 或使用 counter_cache: :flight_count 将自定义列名称传递给它

来源https://guides.rubyonrails.org/association_basics.html#options-for-belongs-to-counter-cache