回滚事务不使用块 [英] Rolling back Transactions Without using a Block

问题描述

注意：这是一个后续问题的优化Rspec的测试，以避免重复复杂的设置Proceedures 的

Note: This is a follow up question to Optimising Rspec Tests to Avoid Repeating Complex Setup Proceedures

有关原因是这个问题的范围（见上述注），我希望能够启动Rails的数据库事务，然后回滚该交易在不同的范围。例如：

For reasons that are outside the scope of this question (see the note above), I want to be able to start a Rails database transaction and then rollback that transaction in a different scope. E.g:

def before_callback
  start_transaction # Start the transaction
  # Create/Update some records
end

def after_callback
  rollback_transaction # Rollback changes from before_callback and do_stuff
end

def do_stuff
  before_callback
  # Do some stuff
  after_callback
end

do_stuff

我意识到这是交易中的人为例子可以很容易地来解决办..结束和一个小重构，但在上下文心目中 do_stuff 的是，我真的不希望惹外部插件的一部分。有没有办法做到像我在Rails的刚才所描述的东西吗？

I realize this is a contrived example which could be resolved easily with transaction do .. end and a little refactoring, but in the context have in mind do_stuff is part of an external plugin that I really don't want to mess with. Is there a way to do something similar to what I just described in Rails?

推荐答案

有关原油快速和肮脏的解决方案，你可以只执行所需的SQL命令直接数据库连接的：

For a crude quick-and-dirty solution you could just execute the required SQL commands directly on the database connection:

def start_transaction
  ActiveRecord::Base.connection.execute("BEGIN")
end

def rollback_transaction
  ActiveRecord::Base.connection.execute("ROLLBACK")
end

另外在看事务的源方法可能给你如何以更精致的方式处理这一一些想法。

Also looking at the source of the transaction method might give you some ideas on how to approach this in a more refined manner.

（你可以找到它在的ActiveRecord :: ConnectionAdapters ::在 DatabaseStatements 的lib / active_record / connection_adapters /抽象/ database_statements.rb ）

(You can find it in ActiveRecord::ConnectionAdapters::DatabaseStatements in lib/active_record/connection_adapters/abstract/database_statements.rb)

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