ruby-on-rails - 如何回滚特定的迁移？(How to rollback a specific migration?)

Question

I have the following migration file db\migrate\20100905201547_create_blocks.rb

(我有以下迁移文件db\migrate\20100905201547_create_blocks.rb)

How can I specifically rollback that migration file?

(如何专门回滚该迁移文件？)

  ask by AnApprentice translate from so

Answer 1

rake db:rollback STEP=1

Is a way to do this, if the migration you want to rollback is the last one applied.

(如果要回滚的迁移是应用的最后一个迁移，则可以这样做。)

You can substitute 1 for however many migrations you want to go back.

(您可以将1替换为您想要返回的许多迁移。)

For example:

(例如：)

rake db:rollback STEP=5

Will also rollback all the migration that happened later (4, 3, 2 and also 1).

(还将回滚稍后发生的所有迁移（4,3,2和1）。)

To roll back all migrations back to (and including) a target migration, use: (This corrected command was added AFTER all the comments pointing out the error in the original post)

(要将所有迁移回滚到（并包括）目标迁移，请使用:(在所有注释指出原始帖子中的错误之后添加了此更正的命令）)

rake db:migrate VERSION=20100905201547

In order to rollback ONLY ONE specific migration (OUT OF ORDER) use:

(为了仅回滚一个特定的迁移（OUT OF ORDER），请使用：)

rake db:migrate:down VERSION=20100905201547

Note that this will NOT rollback any interceding migrations -- only the one listed.

(请注意，这不会回滚任何中间迁移 - 仅列出所迁移的迁移。)

If that is not what you intended, you can safely run rake db:migrate and it will re-run only that one, skipping any others that were not previously rolled back.

(如果这不是你想要的，你可以安全地运行rake db:migrate ，它将只重新运行那个，跳过之前没有回滚过的任何其他的。)