ruby on rails - How to validate uniqueness in join table record

Question

I have 3 models: Open House, Attendee, and Registration (Registration is a join model to allow attendees to register for open houses. A registration belongs to an Open House and an attendee).

How do I create a validation on the Open House model that prevents an Attendee from registering twice for the same Open House?

I'm a little confused because the :attendee_id is on the Registration rather than the Open House, and that is the attribute that defines uniqueness in this scenario. Any help is appreciated!

question from:https://stackoverflow.com/questions/65945029/how-to-validate-uniqueness-in-join-table-record

Answer 1

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