参数数量错误（1 代表 0） Hartl 第 10 章 ...bundle exec rake db:populate

Question

我是 Rails 新手，现在正在学习 Hartl Tutotial。我在使用

填充数据库时遇到了错误

bundle exec rake db:populate 

这是我的 sample_date.rake

namespace :db do
desc "Fill database with sample data"
task populate: :environment do
admin = User.create!(name: "Example User",
                     email: "example@railstutorial.org",
                     password: "foobar",
                     password_confirmation: "foobar",
                     admin: true)

99.times do |n|
  name  = Faker::Name.name
  email = "example-#{n+1}@railstutorial.org"
  password  = "password"
  User.create!(name: name,
               email: email,
               password: password,
               password_confirmation: password)
end
users = User.all(limit: 6)
50.times do
  content = Faker::Lorem.sentence(5)
  users.each { |user| user.microposts.create!(content: content) }
end
end
end

错误是指参数“Users.all”的第 24 行，但这里的问题是什么？？我检查了我所有的 rb 文件，但它们与教程标签匹配。

$ bundle exec rake db:populate --trace
** Invoke db:populate (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:populate
rake aborted!
ArgumentError: wrong number of arguments (1 for 0)
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-4.1.1/lib /active_record/scoping/named.rb:24:in `all'
C:/Users/Christian/Documents/Aptana Studio 3 Workspace/Tutorial3/lib/tasks/sample_data.rake:19:in `block (2 levels) in
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/task.rb:240:in `call'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/task.rb:240:in `block in execute'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/task.rb:235:in `each'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/task.rb:235:in `execute'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/task.rb:179:in `block in invoke_with_call_cha
c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/task.rb:172:in `invoke_with_call_chain'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/task.rb:165:in `invoke'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:150:in `invoke_task'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:106:in `block (2 levels) in to
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:106:in `each'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:106:in `block in top_level'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:115:in `run_with_threads'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:100:in `top_level'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:78:in `block in run'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:176:in `standard_exception_han
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/lib/rake/application.rb:75:in `run'
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-10.3.2/bin/rake:33:in `<top (required)>'
c:/RailsInstaller/Ruby1.9.3/bin/rake:23:in `load'
c:/RailsInstaller/Ruby1.9.3/bin/rake:23:in `<main>'
Tasks: TOP => db:populate

这是我的宝石文件：

来源'https://rubygems.org'

gem 'rails', '4.1.1'
gem "twitter-bootstrap-rails"
gem "bootstrap-sass", '~> 3.1.1.1'
gem 'sprockets', '~> 2.11.0'
gem 'bcrypt-ruby', '3.1.2'
gem 'faker', '1.1.2'
gem 'will_paginate', '3.0.5'
gem 'bootstrap-will_paginate', '0.0.10'
group :development, :test do
gem 'sqlite3'
gem 'rspec-rails', '2.14.2'
end
group :assets do 
gem 'sass-rails', '~> 4.0.3'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.0.0'
end
gem 'jquery-rails'
group :test do
  gem 'capybara', '2.2.1'
end
group :production do
  gem 'rails_12factor'
end
gem 'turbolinks'
gem 'jbuilder', '~> 2.0'
gem 'sdoc', '~> 0.4.0',          group: :doc
gem 'tzinfo-data', platforms: [:mingw, :mswin]

非常感谢您的帮助...我被困在这里了！

Answer 1

使用

users = User.all.limit(6)

或者只是

users = User.limit(6)

'all' 方法不带参数。 http://apidock.com/rails/ActiveRecord/Scoping/Named/ClassMethods/all