Validate uniqueness of in association

Question

Given the following classes:

class Candidate
  has_many :applications
  has_many :companies, :through => :job_offers
end

class JobOffer
  belongs_to :company         


        

Answer 1

As the image points out, a candidate and a job offer will have many applications & a candidate can only apply to one job offer per company. So, validating uniqueness of candidate scoped to a job offer in application might do.

class Candidate
  has_many :applications
  has_many :job_offers, :through => :applications
end

class JobOffer
  belongs_to :company
  has_many :applications
  has_many :candidates, :through => :applications
end

class Application
  belongs_to :candidate
  belongs_to :job_offer

  validates_uniqueness_of :candidate_id, :scope => :job_offer_id
end

This will prevent an application to be associated to the same candidate for the same job offer. The candidate can apply to other job offers, right?

And as pointed out by @ez., renaming application to something appropriate is better.

Hope this helps.