Ruby on Rails，活动记录更新
正在编写 Ruby on Rails 教程。我刚刚注意到，在生成迁移时，我拼错了其中一个列名称。当我尝试与关联合作时，我收到此错误。
first_page = Page.new(:name => "first page", :permalink => 'first', :position => 1)
ActiveRecord::UnknownAttributeError: unknown attribute: position
from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.8/lib/active_record/base.rb:1564:in `attributes='
from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.8/lib/active_record/base.rb:1560:in `each'
from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.8/lib/active_record/base.rb:1560:in `attributes='
from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.8/lib/active_record/base.rb:1412:in `initialize'
from (irb):5:in `new'
from (irb):5
>>
我的问题是如何使用职位的正确拼写更新活动记录。我已经在我的架构文件中更改了它。
working on a tutorial for Ruby on Rails. I just noticed that I had miss-spelled one of my column names when I generated my migrations. When I try to work with associations I get this error.
first_page = Page.new(:name => "first page", :permalink => 'first', :position => 1)
ActiveRecord::UnknownAttributeError: unknown attribute: position
from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.8/lib/active_record/base.rb:1564:in `attributes='
from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.8/lib/active_record/base.rb:1560:in `each'
from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.8/lib/active_record/base.rb:1560:in `attributes='
from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.8/lib/active_record/base.rb:1412:in `initialize'
from (irb):5:in `new'
from (irb):5
>>
My question is how do I update active record with the correct spelling of the Position. I've changed it in my Schema file.
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您应该使用迁移功能来更新架构，而不是手动执行此操作。
在此处查找更多信息：http://guides.rubyonrails.org/migrations.html
You should use the migration feature to update your schema rather than doing that manually.
Find more info here: http://guides.rubyonrails.org/migrations.html
如果您已经提交/推送了迁移，那么其他人可能已经执行了它，因此您最好使用新的迁移来解决问题，来自@Ed Haywood：
如果您没有共享此迁移，则可以修复迁移而不是创建一个新的。撤消上次迁移
然后修复迁移并再次运行
rake db:migrate您应该永远不要手动编辑 schema.rb，它会在每次运行迁移时更新。在您没有编辑它的情况下，当您解决问题时它应该是正确的。
If you already commit/push your migration, it is possible than other people already execute it so you are better to fix the problem with a new migration, from @Ed Haywood :
If you do not have shared this migration, you can fix the migration instead of creating a new one. To undo the last migration
Then fix your migration and run it again
rake db:migrateYou should never edit your schema.rb manually, it is updated each time you run a migration. In your case without editing it, it should be correct when you have fixed the problem.
切勿手动编辑架构。这不会对您的数据库表进行任何更改。
只需运行新的迁移来重命名列：
要回答您的问题“如何更新 Active Record”，您对您的术语有点不清楚。您的意思是“如何更新数据库表”？如果是这样，答案是回滚迁移并修复它，或者运行新的迁移。两者都可以，但回滚可能会导致生产模式下的数据丢失（我认为这不是您的情况）。
要更改模型，您只需在文本编辑器中打开 ruby 文件并进行更改即可。
Never edit the schema manually. That will not make any changes to your database tables.
Simply run a new migration to rename the column:
To answer your question "How do I update Active Record", you're being a bit unclear with your terms. Do you mean "How do I update the database table"? If so, the answer is either rollback your migration and fix it, or run a new migration. Either will work, but rollbacks can cause data loss in production mode (which I assume is not your case).
To change the models you simply open the ruby file in a text editor and change it.
修复您的初始迁移以获得正确的拼写，然后运行：
这将删除您的开发数据库（以及其中的任何数据！），创建一个空的开发数据库，然后针对它重新运行所有定义的迁移。
fix your initial migration to have the correct spelling, then run:
This will delete your development database (and any data in it!), create an empty development db, and re-run all the defined migrations against it.
通常我会回滚迁移（使用 rake db:rollback），修复它并再次运行；
Usually I rollback the migration (with rake db:rollback), fix it and run it again;