"The whole callback chain is wrapped in a transaction. If any before callback method returns exactly false or raises an exception, the execution chain gets halt

"The whole callback chain is wrapped in a transaction. If any before callback method returns exactly false or raises an exception, the execution chain gets halted and a ROLLBACK is issued; after callbacks can only accomplish that by raising an exception." ― http://guides.rubyonrails.org/active_record_validations_callbacks.html#halting-execution http://guides.rubyonrails.org/active_record_validations_call...