Ruby-on-rails 在 rails 中显示挂起的迁移
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Show pending migrations in rails
提问by Readonly
Is there a rake task that shows the pending migrations in a rails app?
是否有一个 rake 任务显示 Rails 应用程序中的待处理迁移？
回答by jrdioko
rake db:migrate:status(Rails 3 to 5) or rails db:migrate:status(Rails 5) will accomplish this. See this commit.
rake db:migrate:status(Rails 3 到 5) 或rails db:migrate:status(Rails 5) 将实现这一点。看到这个提交。
upmeans the migration has been run. downmeans the migration has not been run.
up意味着迁移已经运行。down表示尚未运行迁移。
回答by theIV
There is rake db:abort_if_pending_migrations(at least in Rails 2.3.3, not sure when it was introduced). The description says 'Raises an error if there are pending migrations'. This seems to be used more as a prerequisite for other tasks, but I'm guessing you could use it for your purposes.
有rake db:abort_if_pending_migrations（至少在 Rails 2.3.3 中，不确定何时引入）。描述说“如果有待处理的迁移，则会引发错误”。这似乎更多地用作其他任务的先决条件，但我猜您可以将它用于您的目的。
EDIT: Here is an example of the output after having just generated and not run a 'test' migration
编辑：这是刚刚生成但未运行“测试”迁移后的输出示例
rails_project theIV$ rake db:abort_if_pending_migrations
(in /Users/theIV/Sites/rails_project/)
You have 1 pending migrations:
20090828200602 Test
Run "rake db:migrate" to update your database then try again.
回答by Deepak Mahakale
This command will list all migrations with their status (UPor DOWN)
此命令将列出所有迁移及其状态（UP或DOWN）
Rails 3 and 4
轨道 3 和 4
rake db:migrate:status
Rails 5
导轨 5
rake db:migrate:status
# Or
rails db:migrate:status
回答by gerryster
rake db:versionwill accomplish this on Rails 2.
rake db:version将在 Rails 2 上实现这一点。
回答by Sairam
This works for rails 5.2
这适用于 rails 5.2
ActiveRecord::Base.connection.migration_context.needs_migration?
回答by John Lockwood
Try rake -h (help) and have a look at rake -n (= rake --dry-run). So probably something like rake -n db:migrate should get you what you want.
尝试 rake -h (help) 并查看 rake -n (= rake --dry-run)。所以可能像 rake -n db:migrate 这样的东西应该能让你得到你想要的。
回答by wondersz1
Might not quite be what OP is asking for, but if you just need to quickly check if any migrations are pending for use in a rake task, without resorting to
可能不是 OP 所要求的，但是如果您只需要快速检查是否有任何迁移正在等待在 rake 任务中使用，而无需求助于
rake db:migrate:status | grep down (might not work if you're on Windows)
耙数据库：迁移：状态| grep down（如果你在 Windows 上可能不起作用）
ActiveRecord::Migration.check_pending! (raises ActiveRecord::PendingMigrationError that you need to rescue)
ActiveRecord::Migration.check_pending！（引发需要救援的 ActiveRecord::PendingMigrationError）
you can use needs_migration? method: https://apidock.com/rails/v4.0.2/ActiveRecord/Migrator/needs_migration%3F/class
你可以使用needs_migration吗？方法：https: //apidock.com/rails/v4.0.2/ActiveRecord/Migrator/needs_migration%3F/class
回答by Foram Thakral
If you want to see how much migration is done or pending you can see using below command.
如果您想查看已完成或待处理的迁移量，您可以使用以下命令查看。
rails db:migrate:status
More on this link: Rails Active Record Migration
有关此链接的更多信息：Rails Active Record Migration
回答by niborg
If you need a bash one-liner to determine whether to run a migration or not (e.g., only migrate in a Heroku release phase commandwhen there is a pending migration), this works:
如果您需要一个 bash one-liner 来确定是否运行迁移（例如，只有在有待处理的迁移时才在Heroku 发布阶段命令中迁移），这有效：
(rails db:migrate:status | grep "^\s*down") && rails db:migrate || echo "No pending migrations found."
回答by puneet18
Following command to check migration status:
以下命令检查迁移状态：
rake db:migrate:status
OR
或者
when you run your server, it will display a message to run your pending migration first.
当您运行服务器时，它会显示一条消息，要求您先运行待处理的迁移。
