1

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 导致输出：
** 调用 db:migrate (first_time)
** 调用 db:environment (first_time)
** 执行数据库：环境
** 调用 db:load_config (first_time)
** 执行 db:load_config
** 执行数据库：迁移
== 20150930051523 CreateObjects：迁移 ====================================
-- create_table(:objects)
   -> 0.0010 秒
耙中止！
StandardError：发生错误，此迁移和所有后续迁移已取消：

未初始化的常量 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 `迁移'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:765:in `迁移'
/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：在“事务”中
/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 `迁移'
/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 `迁移'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/tasks/database_tasks.rb:137：在“迁移”中
/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：未初始化的常量 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 `迁移'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/migration.rb:765:in `迁移'
/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：在“事务”中
/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 `迁移'
/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 `迁移'
/var/lib/gems/2.1.0/gems/activerecord-4.2.4/lib/active_record/tasks/database_tasks.rb:137：在“迁移”中
/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 `'
任务：TOP => db:migrate

在 Object.create... 阶段出现错误，出了什么问题？

4

2 回答 2

0

更新：在评论中指出实际代码不包含“对象”，因此此答案基于错误的示例。

Object用于（无范围的）模型类是一个不好的名称，因为它已经由 Ruby 定义。

Object您调用 create 的可能不是您在模型源中定义的类Object。

我假设你运行rails。Object.create从迁移中删除这些行。运行它，它应该可以正常工作。然后，调用rails console，您将进入实时会话。在这里您可以使用您的代码，例如 callObject.create等Object.where{id: 1}。我假设您会得到相同的错误。

因此，作为一种解决方案，将您的重命名Object为其他名称，例如Class并查看它是否有效。

好吧，那是个玩笑，当然Class对于模型类来说也是一个非常糟糕的名字:)。尝试寻找更有意义的东西。

于 2015-09-30T07:51:36.873 回答
0

通过设置 pg gem 解决了这个问题，它拉取了另一个 gem 和包（特别是 postgresql-server-dev-all）。安装后，命令 rake db:migrate 工作正常且完全。

于 2015-10-03T10:46:46.710 回答