名称错误：主题，耙db：重置错误，我无法确定的来源

Question

当我耙db：重置时，我不断在我的终端中出现以下错误。我不知道为什么主题对象是未定义的。我创建了一个主题控制器和模型，这里的代码：

NameError: undefined local variable or method `topics' for main:Object 
/Users/ericpark/rails_projects/code/bloccit/db/seeds.rb:26:in `block in <top (required)>' 
/Users/ericpark/rails_projects/code/bloccit/db/seeds.rb:23:in `times' 
/Users/ericpark/rails_projects/code/bloccit/db/seeds.rb:23:in `<top (required)>' 
/Users/ericpark/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `load' 
/Users/ericpark/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `block in load' 
/Users/ericpark/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:240:in `load_dependency' 
/Users/ericpark/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `load' 
/Users/ericpark/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/engine.rb:547:in `load_seed' 
/Users/ericpark/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/tasks/database_tasks.rb:250:in `load_seed' 
/Users/ericpark/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/railties/databases.rake:180:in `block (2 levels) in <top (required)>' 
/Users/ericpark/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/railties/databases.rake:139:in `block (2 levels) in <top (required)>' 
Tasks: TOP => db:setup => db:seed 
Error 

主题控制器

class TopicsController < ApplicationController 
    def index 
    @topics = Topic.all 
    #authorize @topics 
    end 

    def new 
    @topic = Topic.new 
    authorize @topic 
    end 

    def show 
    @topic = Topic.find(params[:topic_id]) 
    #authorize @topic 
    end 

    def edit 
    @topic = Topic.find(params[:id]) 
    authorize @topic 
    end 

    def create 
    @topic = Topic.new(params.require(:topic).permit(:name, :description, :public)) 
    authorize @topic 
    if @topic.save 
     redirect_to @topic, notice: "Topic was saved successfully." 
    else 
     flash[:error] = "Error creating topic. Please try again." 
     render :new 
    end 
    end 

    def update 
    @topic = Topic.find(params[:id]) 
    authorize @topic 
    if @topic.update_attributes(params.require(:topic).permit(:name, :description, :public)) 
     redirect_to @topic 
    else 
     flash[:error] = "Error saving topic. Please try again." 
     render :edit 
    end 
    end 
end 

主题模式

class Topic < ActiveRecord::Base 
    has_many :posts 
end 

Seed.rb

require 'faker' 

5.times do 
    user = User.new(
    name:  Faker::Name.name, 
    email: Faker::Internet.email, 
    password: Faker::Lorem.characters(10) 
    ) 
    user.skip_confirmation! 
    user.save! 
end 
users = User.all 

#Create Topics 
15.times do 
    Topic.create!(
    name:   Faker::Lorem.sentence, 
    description: Faker::Lorem.paragraph 
    ) 
end 

# Create Posts 
50.times do 
    Post.create!(
    user: users.sample, 
     topic: topics.sample, 
    title: Faker::Lorem.sentence, 
    body: Faker::Lorem.paragraph 
    ) 
end 
posts = Post.all 

# Create Comments 
100.times do 
    Comment.create!(
     #We have not yet associated users with comments 
    post: posts.sample, 
    body: Faker::Lorem.paragraph 
    ) 
end 

topics=Topic.all 

# user = User.first 
# user.skip_reconfirmation! 
# user.update_attributes!(
# email: 'erichoonpark@gmail.com', 
# password: 'bullseye' 
#) 

admin = User.new(
    name: 'Admin User', 
    email: 'admin@example.com', 
    password: 'examplepass', 
    role: 'admin' 
) 
admin.skip_confirmation! 
admin.save! 

moderator = User.new(
    name: 'Moderator', 
    email: 'moderator@example.com', 
    password: 'examplepass', 
    role: 'moderator' 
) 
moderator.skip_confirmation! 
moderator.save! 

member = User.new(
    name: 'User', 
    email: 'user@example.com', 
    password: 'examplepass' 
) 
member.skip_confirmation! 
member.save! 


puts "Seed finished" 
puts "#{User.count} users created" 
puts "#{Post.count} posts created" 
puts "#{Comment.count} comments created" 

可能有人解释为什么话题是不确定的编辑为终端？当我创建topics.sample时，我究竟在做些什么？它是控制器吗？

谢谢！

Answer 1

这与控制器无关。 topics未在seeds.rb中定义，因为没有定义它。你可能只是设定

topics = Topic.all 

您所创建的主题后，然后将topics.sample随机从数组