ruby-on-rails - 如何在Ruby on Rails迁移中重命名数据库列？(How can I rename a database column in a Ruby on Rails migration?)

Question

I wrongly named a column hased_password instead of hashed_password .

(我错误地将列命名为hased_password而不是hashed_password 。)

How do I update the database schema, using migration to rename this column?

(如何使用迁移重命名此列来更新数据库架构？)

  ask by user1994764 translate from so

Answer 1

rename_column :table, :old_column, :new_column

Update:

(更新：)

You'll probably want to create a separate migration to do this.

(您可能希望创建单独的迁移来执行此操作。)

(Rename FixColumnName as you will)

(（按照您的意愿重命名FixColumnName）)

script/generate migration FixColumnName
# creates  db/migrate/xxxxxxxxxx_fix_column_name.rb

Then edit the migration to do your will.

(然后编辑迁移以执行您的意愿。)

# db/migrate/xxxxxxxxxx_fix_column_name.rb
class FixColumnName < ActiveRecord::Migration
  def self.up
    rename_column :table_name, :old_column, :new_column
  end

  def self.down
    # rename back if you need or do something else or do nothing
  end
end

---

An update for Rails 3.1

(Rails 3.1的更新)

While, the up and down methods still apply.

(同时，在up和down的方法仍然适用。)

Rails 3.1 receives a change method that "knows how to migrate your database and reverse it when the migration is rolled back without the need to write a separate down method"

(Rails 3.1接收一个change方法， “知道如何迁移数据库并在回滚迁移时将其反转，而无需编写单独的down方法”)

rails g migration FixColumnName

class FixColumnName < ActiveRecord::Migration
  def change
    rename_column :table_name, :old_column, :new_column
  end
end

---

If you happen to have a whole bunch of columns to rename, or something that would have required repeating the table name over and over again.

(如果您碰巧有一大堆要重命名的列，或者需要一遍又一遍地重复表名的内容。)

rename_column :table_name, :old_column1, :new_column1
rename_column :table_name, :old_column2, :new_column2
...

You could use change_table to keep things a little neater.

(你可以使用change_table来保持一点整洁。)

class FixColumnNames < ActiveRecord::Migration
  def change
    change_table :table_name do |t|
      t.rename :old_column1, :new_column1
      t.rename :old_column2, :new_column2
      ...
    end
  end
end

Thank you, Luke && Turadg , for bringing up the topic.

(感谢Luke && Turadg提出这个话题。)

Then just db:migrate as usual or however you go about your business.

(然后只是db:migrate像往常一样db:migrate ，或者你继续开展业务。)

---

An update for Rails 4

(Rails 4的更新)

While creating a Migration as for renaming a column, Rails 4 generates a change method instead of up and down as mentioned in the above answer.

(在创建Migration作为用于重命名的列，轨道4产生change的方法，而不是up和down如在上面提到的答案。)

The generated change method is as below :

(生成的change方法如下：)

$ > rails g migration ChangeColumnName

which will create a migration file similar to this :

(这将创建一个类似于此的迁移文件：)

class ChangeColumnName < ActiveRecord::Migration
  def change
    rename_column :table_name, :old_column, :new_column
  end
end