Ruby-on-rails 更改列名 Rails

change column name Rails

提问by Pere

I have this table:

我有这张桌子：

class CreateShoes < ActiveRecord::Migration
  def change
    create_table :shoes do |t|
      t.string :name
      t.boolean :leather
      t.integer :season

      t.timestamps null: false
    end
  end
end

the 'season' column should be called 'season_id'. I know that I have to write 't.rename :season, :season_id' as explained in http://edgeguides.rubyonrails.org/active_record_migrations.html#column-modifiersbut I don't manage to find the right syntax. Should it be?

“季节”列应称为“季节 ID”。我知道我必须按照http://edgeguides.rubyonrails.org/active_record_migrations.html#column-modifiers 中的说明编写 't.rename :season, :season_id'但我找不到正确的语法。应该是吗？

class CreateShoes < ActiveRecord::Migration
  def change
    create_table :shoes do |t|
      t.string :name
      t.boolean :leather
      t.integer :season

      t.timestamps null: false
    end

    change_table :products do |t|
      t.rename :season, :season_id
    end

  end
end

Doesn't work. Anything I have to do in the Mac console? Thanks!

不起作用。我必须在 Mac 控制台中做些什么？谢谢！

回答by Inpego

Run in your console:

在您的控制台中运行：

$ rails g migration rename_season_to_season_id

Now file db/migrate/TIMESTAMP_rename_season_to_season_id.rbcontains following:

现在文件db/migrate/TIMESTAMP_rename_season_to_season_id.rb包含以下内容：

class RenameSeasonToSeasonId < ActiveRecord::Migration
  def change
  end
end

Modify it as follows:

修改如下：

class RenameSeasonToSeasonId < ActiveRecord::Migration
  def change
    rename_column :shoes, :season, :season_id
  end
end

Then run $ rake db:migratein console.

然后$ rake db:migrate在控制台运行。

回答by ruby_newbie

Either fix your migration and do

要么修复你的迁移，然后做

rake db:rollback db:migrate

or make another migration like so:

或者像这样进行另一次迁移：

rename_column :shoes, :season, :season_id if column_exists?(:shoes, :season) && !column_exists?(:shoes, :season_id)

and then do

然后做

rake db:migrate

回答by Sushant

If your branch has been pushed to production then one probably needs to add the new migration by running the following command:

如果您的分支已推送到生产，那么您可能需要通过运行以下命令来添加新的迁移：

rails g migration RenameSeasonColumnNameToShoes

rails g migration RenameSeasonColumnNameToShoes

and if it hasn't been pushed to production or you have to currently make changes to your branch only, then do:

如果它还没有被推送到生产环境或者你目前只需要对你的分支进行更改，那么执行以下操作：

bundle exec rake db:rollback

bundle exec rake db:rollback

Then make changes to your migration file inside /db/migrate/<your_migration_file_name>

然后在里面修改你的迁移文件 /db/migrate/<your_migration_file_name>

Then in your migration file, using rename_columndo as follows:

然后在您的迁移文件中，使用rename_columndo 如下：

class RenameSeasonColumnNameToShoes < ActiveRecord::Migration
  def change
      rename_column :shoes, :season, :season_id
  end
end

and then do

然后做

bundle exec rake db:migrate db:test:prepare

bundle exec rake db:migrate db:test:prepare

回答by dixpac

If your intention is to rename column in table than you example migration is not making sense :)... Instead of this

如果您打算重命名表中的列，那么示例迁移没有意义:)... 而不是这个

class CreateShoes < ActiveRecord::Migration
  def change
    create_table :shoes do |t|
      t.string :name
      t.boolean :leather
      t.integer :season

      t.timestamps null: false
    end

    change_table :products do |t|
      t.rename :season, :season_id
    end

  end
end

You just need table change migration, like this(Rails will take care rollback for your):

您只需要表更改迁移，就像这样（Rails 会为您处理回滚）：

class RenameSessionColumnInsideShoes < ActiveRecord::Migration
  def change
    change_table :products do |t|
      t.rename :season, :season_id
    end
  end
end

renamemethod on table object in rails is valid method, as you can see in Rails source code

renamerails 中 table 对象的方法是有效的方法，如您在 Rails 源代码中所见

https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb#L582

https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb#L582