16

我试图运行：

rake db:migrate VERSION=0

它会还原除最后一个迁移之外的所有迁移。

然后我尝试运行：

rake db:migrate:down VERSION=<timestamp_of_last_migration>

但它也没有恢复。为什么 ？

有没有一次运行所有down方法的命令？

4

4 回答 4

11

如果您的数据库仅与该项目相关，并且您试图撤消迁移中的所有内容，我只需删除数据库，然后运行 ​​rake db:create。

然后你有一个空的数据库准备好了。

还是您尝试运行向下脚本的其他原因？

于 2010-12-09T05:55:58.573 回答
10

你可以检查这个列表。

也许这可以帮助你

rake db:create[:all]: If :all not specified then create the database defined in config/database.yml for the current RAILS_ENV. If :all is specified then create all of the databases defined in config/database.yml.
rake db:fixtures:load: Load fixtures into the current environment's database. Load specific fixtures using FIXTURES=x,y
rake db:migrate [VERSION=n]: Migrate the database through scripts in db/migrate. Target specific version with VERSION=n
rake db:migrate:redo [STEP=n]: (2.0.2) Revert the database by rolling back "STEP" number of VERSIONS and re-applying migrations.
rake db:migrate:reset: (2.0.2) Drop the database, create it and then re-apply all migrations. The considerations outlined in the note to rake db:create apply.
rake db:reset: Drop and re-create database using db/schema.rb. The considerations outlined in the note to rake db:create apply.
rake db:rollback [STEP=N]: (2.0.2) Revert migration 1 or n STEPs back.
rake db:schema:dump: Create a db/schema.rb file that can be portably used against any DB supported by AR
rake db:schema:load: Load a schema.rb file into the database
rake db:sessions:clear: Clear the sessions table
rake db:sessions:create: Creates a sessions table for use with CGI::Session::ActiveRecordStore
rake db:structure:dump: Dump the database structure to a SQL file
rake db:test:clone: Recreate the test database from the current environment's database schema
rake db:test:clone_structure: Recreate the test databases from the development structure
rake db:test:prepare: Prepare the test database and load the schema
rake db:test:purge: Empty the test database
于 2010-12-09T17:27:26.953 回答
7

还有另一种方法：

rake db:rollback STEP=100

这将恢复最后 100 次迁移

taken from http://guides.rubyonrails.org/migrations.html#rolling-back

于 2013-09-26T11:16:59.363 回答
2

尝试：

rake db:migrate:down VERSION=<timestamp_of_first_migration>

这将为您的第一次迁移运行 self.down，基本上清除所有内容。至少，它对我有用！

于 2011-01-31T07:34:00.473 回答