Rails db:种子错误"未定义的方法`finder_needs_type_condition？' 为零:NilClass"

Question

尝试填充我的sqlite数据库时遇到问题.关于特定错误"finder_needs_type_condition？"的信息不多.我可以找到,但我对Rails没有多少经验,甚至怀疑问题可能在哪里.

模型:

class Character < ActiveRecord::Base
  validates :user_id, :name, :class, presence: true
end

控制器:

class CharactersController < ApplicationController
  before_action :authenticate_user!
  respond_to :json

  @user_id = current_user[:id]

  def index
    @characters = Character.all
  end

  def show
    @character = Character.find(params[:id])
  end

  def new
    @character = Character.new
  end

  def create
    @characters = Character.all
    @character = Character.create(character_params)
  end

  private
    def character_params
      params.require(:character).permit(:user_id, :name, :class)
    end
end

schema.rb:

create_table "characters", force: :cascade do |t|
  t.datetime "created_at",             null: false
  t.datetime "updated_at",             null: false
  t.string   "name"
  t.string   "class"
  t.integer  "user_id",    default: 0, null: false
end

seeds.rb:

Character.delete_all
Character.create!([
  {id: 1, name: "nameone", class: "Warrior", user_id: 1},
  {id: 2, name: "nametwo", class: "Mage", user_id: 1},
  {id: 3, name: "namethree", class: "Wizard", user_id: 1},
  {id: 4, name: "namefour", class: "Warlock", user_id: 1},
  {id: 5, name: "namefive", class: "Rogue", user_id: 1}
])

尝试种子时的错误:

$ bundle exec rake db:seed
rake aborted!
NoMethodError: undefined method `finder_needs_type_condition?' for nil:NilClass
/var/rubyapps/test/db/seeds.rb:2:in `<top (required)>'
Tasks: TOP => db:seed

在生成模型时我误解了什么吗？

Answer 1

您不能拥有列名class,因为这是一个保留字.您已经character_class在种子中使用了数据库中不存在的种子,因此您需要做的就是将此列重命名为数据库.

rails g migration RenameCharactersClassColumn

然后将此行添加到迁移文件中.

rename_column :characters, :class, :character_class

运行rake db:migrate,这应该解决它.