Rails教程user.save提供参数错误(1为0)

Question

首先，这是一个在这里发布文章的菜鸟，所以如果我的格式是关闭的或者类似的东西，请告诉我，我很乐意修复它:)

我一直在学习迈克尔·哈特尔的Rails教程，它非常棒。我确信我的问题是因为我没有正确地做一些事情，但是我在网上找不到任何能解决我的问题的东西。

我在第6章中创建了一个用户数据库。在我尝试做user.save之前，一切都很好

为了供参考，下面是导致问题的步骤：

rails generate model User name:string email:string

然后：

bundle exec rake db:migrate 

打开沙箱控制台：

 rails console --sandbox

创建一个新用户

user = User.new(name: "Michael Hartl", email: "mhartl@example.com")

保存它：

user.save

所有东西都给出了预期的输出，直到user.save给出了这样的结果

irb(main):002:0> user.save (0.1ms) SAVEPOINT active_record_1 (0.1ms)回滚到SAVEPOINT active_record_1 ArgumentError:错误数量的参数(1为0)来自于抽象_适配器.irb:271：在/Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adap /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4中的initialize' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adap ters/abstract_adapter.rb:271:in中，new‘from _ters_Adapter.rb:271 :in substitute_at' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:97: in块in substitute_values’.2.0.beta 4/lib/active_record/Relation.rb:96: in each' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:96: ineach_with_index‘from each' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:96: ineach_with_index in substitute_values' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:56: in插入’from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb: 521:in _create_record' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/counter_cache.r b:139:in_create_record‘from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/attribute_metho ds/dirty.rb:122:in _create_record' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:30 6:inblock in _create_record’来自/Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb: 88:in call' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb: 88:in_run_callbacks‘in /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb：734:在_run_create_callbacks' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:30 6:in_create_record‘. 22层.从/Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands/console.rb:9:in s tart' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands/commands_tasks.rb: 68:inconsole‘到/Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands/commands_tasks.rb: 39:in来自/Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.的run_command!' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands.rb:17:in‘rb:252:在/Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.中的require' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies. rb:252:in块中rb:237:在/Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.中，load_dependency' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies. rb:252:in要求‘from /User/Jonathon/Aptana 3 Workspace/RoR/bin/rails:8:in <top (required)>' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies. rb:246:inload’rb:246:in block in load' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies. rb:237:inload_dependency‘inblock in load' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies. rb:237:inload_dependencyrb:246:in load' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:inrequire‘from load' from /Users/Jonathon/.rbenv/versions/2.1.3/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in require' from -e:1:in'irb(main):003:0>

我已经将我的user.rb文件放在这里：

class User < ActiveRecord::Base end

还有我的create_users.rb文件

class CreateUsers < ActiveRecord::Migration def change create_table :users do |t| t.string :name t.string :email t.timestamps null: false end end end

谢谢，如果我还需要提供更多的信息，请告诉我！

Answer 1

谢谢大家的帮助！

斯拉斯贝尔是对的，结果是我的数据库出了问题。克隆了本教程git并解决了问题。

Answer 2

我也有同样的问题。一开始，当我像你一样尝试ArgumentError时，我就有了user.save。然后，当我尝试rake db:drop和rake db:migrate时，也遇到了同样的错误。

对于我的情况，它是在bundle update之后，我发现这个arel创业板版本造成了问题。它在Gemfile.lock上显示了Gemfile.lock，但是当我像以前一样尝试arel (6.0.0.beta2)时，它起了作用。

我也不知道原因。不过，我找到了这一讨论。现在我们的非beta Rails 4.2.0没有问题，如果我们没有在示例应用程序上使用bundle update (正如作者所说)，Hartl教程也没有问题。