脚手架后无法迁移数据库。第 2.2 节 Ruby on Rails 教程 Michael Hartl答案

【问题标题】：Can't migrate database after scaffold. Section 2.2 Ruby on Rails Tutorial Michael Hartl脚手架后无法迁移数据库。第 2.2 节 Ruby on Rails 教程 Michael Hartl
【发布时间】：2015-01-24 04:22:24
【问题描述】：

我正在学习 Hartl ruby on rails 教程（第 2.2 节），但在迁移数据库时遇到了问题。一切似乎都正常，然后我运行 rails generate scaffold User name:string email:string 之后我尝试运行 bundle exec rake db:migrate 并收到以下错误消息：

$ bundle exec rake db:migrate
                                                                                 == 20141125234257 CreateUsers: migrating ======================================
-- create_table(:users)
   -> 0.0079s
== 20141125234257 CreateUsers: migrated (0.0080s) =============================

rake aborted!
StandardError: An error has occurred, this and all later migrations canceled:

wrong number of arguments (1 for 0)/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract_adapter.rb:271:in `initialize'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract_adapter.rb:271:in `new'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract_adapter.rb:271:in `substitute_at'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:97:in `block in substitute_values'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:96:in `each'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:96:in `each_with_index'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:96:in `substitute_values'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:56:in `insert'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb:521:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/counter_cache.rb:139:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/attribute_methods/dirty.rb:122:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:306:in `block in _create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:88:in `call'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:88:in `_run_callbacks'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:734:in `_run_create_callbacks'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:306:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/timestamp.rb:57:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb:501:in `create_or_update'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:302:in `block in create_or_update'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:88:in `call'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:88:in `_run_callbacks'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:734:in `_run_save_callbacks'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:302:in `create_or_update'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb:142:in `save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/validations.rb:42:in `save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/attribute_methods/dirty.rb:29:in `save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:289:in `block in save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:345:in `block in with_transaction_returning_status'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:218:in `transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:342:in `with_transaction_returning_status'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:289:in `save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb:51:in `create!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:1015:in `record_version_state_after_migrating'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:985:in `block in execute_migration_in_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:1030:in `block in ddl_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract/transaction.rb:188:in `within_new_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:218:in `transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:1030:in `ddl_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:983:in `execute_migration_in_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:945:in `block in migrate'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:941:in `each'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:941:in `migrate'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:813:in `up'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:791:in `migrate'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>'
ArgumentError: wrong number of arguments (1 for 0)
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract_adapter.rb:271:in `initialize'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract_adapter.rb:271:in `new'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract_adapter.rb:271:in `substitute_at'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:97:in `block in substitute_values'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:96:in `each'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:96:in `each_with_index'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:96:in `substitute_values'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/relation.rb:56:in `insert'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb:521:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/counter_cache.rb:139:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/attribute_methods/dirty.rb:122:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:306:in `block in _create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:88:in `call'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:88:in `_run_callbacks'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:734:in `_run_create_callbacks'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:306:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/timestamp.rb:57:in `_create_record'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb:501:in `create_or_update'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:302:in `block in create_or_update'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:88:in `call'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:88:in `_run_callbacks'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activesupport-4.2.0.beta4/lib/active_support/callbacks.rb:734:in `_run_save_callbacks'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/callbacks.rb:302:in `create_or_update'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb:142:in `save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/validations.rb:42:in `save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/attribute_methods/dirty.rb:29:in `save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:289:in `block in save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:345:in `block in with_transaction_returning_status'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:218:in `transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:342:in `with_transaction_returning_status'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:289:in `save!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/persistence.rb:51:in `create!'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:1015:in `record_version_state_after_migrating'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:985:in `block in execute_migration_in_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:1030:in `block in ddl_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract/transaction.rb:188:in `within_new_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/transactions.rb:218:in `transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:1030:in `ddl_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:983:in `execute_migration_in_transaction'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:945:in `block in migrate'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:941:in `each'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:941:in `migrate'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:813:in `up'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/migration.rb:791:in `migrate'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
/usr/local/rvm/gems/ruby-2.1.4@rails4/gems/activerecord-4.2.0.beta4/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

我尝试返回之前的提交并再次运行所有内容，但我收到相同的错误消息。还有什么我应该添加的文件可以帮助解决这个问题吗？

【问题讨论】：

您确实应该使用编写本教程的 Rails 版本。否则你可能会遇到各种各样的问题。
@sevenseacat，使用最新版本的 RT 第 3 版中描述的 rails 和其他 gem 的确切版本会出现此问题。我刚刚给作者 Michael Hartl 发了一封便条。
收到 Michael 的回复，他告诉我这个问题已于 2014 年 11 月 26 日星期三得到纠正。确保您的 Gemfile 来自之后，这应该不是问题。

标签： ruby-on-rails rake migrate scaffold dbmigrate

【解决方案1】：

我已经解决了这个问题

rake db:reset

之后

rake db:migrate

工作。

【讨论】：

【解决方案2】：

使用上述更改 gemfile 的解决方案。

 gem 'arel', '6.0.0.beta2'

我收到以下错误消息。

You have requested:arel = 6.0.0.beta2

The bundle currently has arel locked at 6.0.0.
Try running `bundle update arel`

之后

bundle update arel

成功了

【讨论】：

【解决方案3】：

我也遇到了这个问题。这是由于 ActiveRecord 4.2.0.beta4 将参数传递给Arel::Nodes::BindParam.new。 Arel 6.0.0 was just released today。在这个版本中，BindParam 的初始化器中不接受任何参数。

ActiveRecord 已经在 master 分支上修复了这个问题。在 beta5 发布之前，您需要将您的 Gemfile 锁定为 gem 'arel', '6.0.0.beta2'。

【讨论】：

非常感谢！像魅力一样工作。
谢谢！ fwiw 这也导致了 rspec 和 factory_girl 的问题；升级到 Arel 6.0.0.beta2 修复了它。
我已经这样做了，它修复了我无法运行 db:migrate - 但是，我的 Rails 应用程序仍然不会按预期添加新用户。错误显示：ArgumentError in UsersController#create wrong number of arguments (1 for 0) Arel 的第 271 行似乎有问题：Arel::Nodes::BindParam.new '?'。欢迎对此有任何想法！
出于某种原因，我在本地收到了该错误 - 但在部署到 heroku 时它工作正常。不知道那里发生了什么。