ruby-on-rails - 种子错误 ActiveModel::UnknownAttributeError:列表的未知属性 'excerpt'

Question

我正在设置我的种子文件以将一些数据添加到我的 Rails 5 应用程序。当我运行 rake db:seed 时出现此错误

rake aborted!
ActiveModel::UnknownAttributeError: unknown attribute 'excerpt' for List.

无法真正理解为什么我得到这个。我使用 PostgreSQL 作为 DB 和 Rails 5.2。我正在尝试构建一个 API。

我设置了数据库进行了迁移，但种子不起作用。

我还有另外两个模型和一个元素 Controller 。

种子文件:

List.create(title:"West Sweden Road Trip", excerpt:"A cool road trip with stops in harbors of the coast")

我的模型是:

class List < ApplicationRecord
  has_many :list_items
  has_many :items, through: :list_items
end

Controller :

module Api::V1
  class ListsController < ApplicationController
    before_action :set_list, only: [:show, :update, :destroy]

    # GET /lists
    def index
      @lists = List.order(:id)

      render json: @lists
    end

    # GET /lists/1
    def show
      render json: @list
    end

    # POST /lists
    def create
      @list = List.new(list_params)

      if @list.save
        render json: @list, status: :created
      else
        render json: @list.errors, status: :unprocessable_entity
      end
    end

    # PATCH/PUT /lists/1
    def update
      if @list.update(list_params)
        render json: @list
      else
        render json: @list.errors, status: :unprocessable_entity
      end
    end

    # DELETE /lists/1
    def destroy
      @list.destroy
      if @list.destroy
        head :no_content, status: :ok
      else
        render json: @list.errors, status: :unprocessable_entity
      end
    end

    private
    # Use callbacks to share common setup or constraints between actions.
    def set_list
      @list = List.find(params[:id])
    end

    # Only allow a trusted parameter "white list" through.
    def list_params
      params.require(:list).permit(:title, :excerpt, :description, :upvotes)
    end
  end
end

我的架构:

ActiveRecord::Schema.define(version: 2018_10_14_135801) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"

  create_table "items", force: :cascade do |t|
    t.integer "type"
    t.string "name"
    t.text "excerpt"
    t.text "description"
    t.string "url"
    t.integer "upvotes"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "list_items", force: :cascade do |t|
    t.bigint "list_id"
    t.bigint "item_id"
    t.text "description"
    t.integer "position"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["item_id"], name: "index_list_items_on_item_id"
    t.index ["list_id"], name: "index_list_items_on_list_id"
  end

  create_table "lists", force: :cascade do |t|
    t.string "title"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  add_foreign_key "list_items", "items"
  add_foreign_key "list_items", "lists"
end

Answer 1

rake aborted! ActiveModel::UnknownAttributeError: unknown attribute 'excerpt' for List.

嗯，List没有名为excerpt的属性，但是Item有摘录属性

改成

List.create(title:"West Sweden Road Trip")

更新:

如果要将excerpt 列添加到List，则生成一个迁移

rails g migration add_excerpt_to_lists excerpt:text

然后执行rake db:migrate