Rolling back Transactions Without using a Block

问题

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

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

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?

回答1:

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

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

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

来源：https://stackoverflow.com/questions/12675128/rolling-back-transactions-without-using-a-block

标签

ruby-on-rails

activerecord