Rails Cheatsheet

Rescuing within a Transaction

{% highlight ruby %} def foo begin ActiveRecord::Base.transaction do p = Post.first p.content = "Once upon a time in Camarin" p.save! # p object is valid and would save at this point p1 = Post.last p1.user_id = nil #lets say this is required p1.save! end rescue ActiveRecord::RecordInvalid => e # at this point, rollback is already done false end end {% endhighlight %}

From the rails guides:

Also have in mind that exceptions thrown within a transaction block will be propagated (after triggering the ROLLBACK), so you should be ready to catch those in your application code."