rake db:migrate导致StandardError - 未初始化的常量CreateObjects :: Object

时间:2015-09-30 07:17:24

标签: ruby activerecord uninitialized-constant

我有迁移20150930051523_create_objects.rb:

class CreateObjects < ActiveRecord::Migration
def change
  create_table :objects do |t|
    t.text :name
    t.timestamps null: false
  end

  Object.create :name => "A"
  Object.create :name => "B"
  Object.create :name => "C"

  end
end
$ rake:db migrate --trace cause output:
** Invoke db:migrate (first_time)
** Invoke db:environment (first_time)
** Execute db:environment
** Invoke db:load_config (first_time)
** Execute db:load_config
** Execute db:migrate
== 20150930051523 CreateObjects: migrating ====================================
-- create_table(:objects)
   -> 0.0010s
rake aborted!
StandardError: An error has occurred, this and all later migrations canceled:

uninitialized constant CreateObjects::Object/db/migrate/20150930051523_create_objects.rb:8:in `change'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:605:in `exec_migration'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:589:in `block (2 levels) in migrate'
/usr/lib/ruby/2.1.0/benchmark.rb:279:in `measure'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:588:in `block in migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:587:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:765:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:995:in `block in execute_migration_in_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:1041:in `block in ddl_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/transaction.rb:184:in `within_new_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/transactions.rb:220:in `transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:1041:in `ddl_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:994:in `execute_migration_in_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:956:in `block in migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:952:in `each'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:952:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:820:in `up'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:798:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/railties/databases.rake:44:in `block (2 levels) in '
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:240:in `call'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:240:in `block in execute'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:235:in `each'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:235:in `execute'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:179:in `block in invoke_with_call_chain'
/usr/lib/ruby/2.1.0/monitor.rb:211:in `mon_synchronize'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:172:in `invoke_with_call_chain'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:165:in `invoke'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:150:in `invoke_task'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:106:in `each'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:106:in `block in top_level'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:115:in `run_with_threads'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:100:in `top_level'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:78:in `block in run'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:176:in `standard_exception_handling'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:75:in `run'
/var/lib/gems/2.1.0/gems/rake-10.4.2/bin/rake:33:in `'
/usr/local/bin/rake:23:in `load'
/usr/local/bin/rake:23:in `'
NameError: uninitialized constant CreateObjects::Object/db/migrate/20150930051523_create_barbers.rb:8:in `change'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:605:in `exec_migration'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:589:in `block (2 levels) in migrate'
/usr/lib/ruby/2.1.0/benchmark.rb:279:in `measure'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:588:in `block in migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:587:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:765:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:995:in `block in execute_migration_in_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:1041:in `block in ddl_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/transaction.rb:184:in `within_new_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/transactions.rb:220:in `transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:1041:in `ddl_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:994:in `execute_migration_in_transaction'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:956:in `block in migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:952:in `each'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:952:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:820:in `up'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:798:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/railties/databases.rake:44:in `block (2 levels) in '
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:240:in `call'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:240:in `block in execute'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:235:in `each'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:235:in `execute'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:179:in `block in invoke_with_call_chain'
/usr/lib/ruby/2.1.0/monitor.rb:211:in `mon_synchronize'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:172:in `invoke_with_call_chain'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/task.rb:165:in `invoke'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:150:in `invoke_task'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:106:in `each'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:106:in `block in top_level'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:115:in `run_with_threads'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:100:in `top_level'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:78:in `block in run'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:176:in `standard_exception_handling'
/var/lib/gems/2.1.0/gems/rake-10.4.2/lib/rake/application.rb:75:in `run'
/var/lib/gems/2.1.0/gems/rake-10.4.2/bin/rake:33:in `'
/usr/local/bin/rake:23:in `load'
/usr/local/bin/rake:23:in `'
Tasks: TOP => db:migrate

在Object.create ......阶段出现错误,出了什么问题?

2 个答案:

答案 0 :(得分:0)

更新:在评论中指出实际代码不包含“对象”,因此这个答案基于错误的例子。

Object是一个用于(unscoped)Model类的错误名称,因为它已经由Ruby定义。

您调用create Object可能不是您在模型源中定义的Object类。

我假设你运行rails。从迁移中删除Object.create行。运行它,它应该工作正常。然后,拨打rails console,最后进入直播会话。在这里,您可以使用您的代码,例如:致电Object.createObject.where{id: 1}等我认为你会得到同样的错误。

因此,作为一种解决方案,请将您的Object重命名为其他内容,例如Class并查看其是否有效。

好的,这是个玩笑,当然Class对于模型类来说也是一个非常糟糕的名字:)。试着找到更有意义的东西。

答案 1 :(得分:0)

问题是通过设置pg gem来解决的,它会拉出另一个宝石和包(特别是postgresql-server-dev-all)。安装后,rake db:migrate命令可以正常工作。