Read more about the shortcomings of application level reference validations here: http://robots.thoughtbot.com/referential-integrity-with-foreign-keys http://ro

Read more about the shortcomings of application level reference validations here: http://robots.thoughtbot.com/referential-integrity-with-foreign-keys http://robots.thoughtbot.com/referential-integrity-with-fore... Note: that post talks about using `foreigner` gem which predates having foreign key support in rails core.