Rails transaction doesn't rollback on validation error.

Question

I have two models: user and company. They both get created from one form and I'm using a transaction like this:

 User.transaction do

  @user.save!

  @company.user = @user
  @company.save!

  @user.reload
  @user.company = @company
  @user.save!

 flash[:notice] = "Thank you for your registration."
  redirect_to_index
end

The user gets saved to the database even when one of the company's validations fails. I've tried adding explicit error handling of ActiveRecord::RecordInvalid but it didn't help. I thought the validation would raise the error to rollback the transaction anyway. Any help is greatly appreciated.

Thanks

Answer 1

http://tempe.st/2007/05/transaction-in-rails/

I believe you must use a begin end block outside the transaction loop.

Answer 2

You will have to consider these scenarios

1. Use a database system that supports transaction
2. Re-Factor that code for a more logical approach

As an example, if you only have a one-to-one relation, it can be handled in more optimized way

Company has_one User
User belongs_to Company

Now, in Company model

@company.user.build(user_attributes)
@company.save  # will save company as well as user

I have not tested it as an example. Just off my mind. Have I understood the problem correctly?

Answer 3

You must use a database engine that supports ACID transactions. For mysql that is INNODB.

show table status\G

If users or companies is not using InnoDB engine, you can change it w/ this command.

ALTER TABLE <table name> ENGINE INNODB;

the exception thrown from @company.save! *should trigger a ROLLBACK command to be sent to the database. you can verify this in the console/logfile when running script/server with DEBUG log level.

Answer 4

save() and destroy() are always under transaction (see http://railsapi.com/doc/rails-v2.3.5/classes/ActiveRecord/Transactions/ClassMethods.html).

What I think you want to be doing is

  begin
    @company = Company.create!(params[:company])
    @user    = User.create!(params[:user]) { |user| user.company => @company }
  rescue => ex
    # ... handle your validation errors
  end

This would solve your problem as when company validations fail an exception will be raised and the User.create statement never executes.