CODEWITHSUNDEEP
ruby-on-railshas-many-through
rwehresmann
rwehresmann

Reputation: 1168

Get extra attribute value from 'has_many through' association

I have the following structure:

In my answer model:

class Answer < ApplicationRecord
  has_many :answer_test_case_results
  has_many :test_cases_result, through: :answer_test_case_results, source: :test_case
end

My answer_test_case_result:

class AnswerTestCaseResult < ApplicationRecord
  belongs_to :answer
  belongs_to :test_case

  def get_output
    output
  end
end

My answer_test_case_result model has an extra attribute, named output. In my answer model I would like access this output from my test_cases_result relationship, however the way it is this attribute returns only the test_case objects saved and associated with this answer.

There is a way to access the output without a query directly from my AnswerTestCaseResult (that is, AnswerTestCaseResult.where(answer: answer, test_case: test_case))?

Upvotes: 1

Views: 198

Answers (1)

rwehresmann
rwehresmann

Reputation: 1168

The scarcity of examples of this kind of operation is unbelievable. But now I understand what I was doing wrong: I should access my has_many :answer_test_case_results, not has_many :test_cases_result, through: :answer_test_case_results, source: :test_case.

And if I want to leave the attribute, for my case, more appropriate semantically, I can use: has_many :test_cases_result, class_name: "AnswerTestCaseResult"

So I can access output through answer.test_cases_reult.first.output, for instance.

Upvotes: 1

Related Questions