Imposing pairing between two relationships indexed as attributes in thinking sphinx search

Question

I have a User model that indexes ProfileAnswer, a has_many relationship. I am indexing profile_answers.response as well profile_answers.question_id .

I need to be able to run search queries that search a string for one particular question.

Here is the way I am doing this which is wrong. with data points

A{

profile_answer{
  id = 99
  question_id = 1
  answer = 'Hi'
}

profile_answer{
  id = 100
  question_id = 2
  answer = 'Bye'
}

}
B{

 profile_answer{
     id = 102
     question_id = 1
    answer = 'Bye'
 }

 profile_answer{
    id = 101
    question_id = 2
    answer = 'Hi'
 }

}

A and B are both returned when I search for 'Hi' on question_id = 2.

Here is my index definition:

 indexes profile_answers.answer, sortable: true, as: "answer"
 has profile_answers.question_id, as: "question_id"

and do my search as:

  User.search('@answer "Hi"', match_mode: :extended, with: {question_id: given_question.id})

I have tried indexing some combination of these columns and search that but that has never produced the right index.

Answer 1

Answered this on the Thinking Sphinx Google group too:

What you’re trying to do is not possible (while searching on Users, at least). Sphinx has no concept of hashes/dictionaries… in your index, each user has a field called answer, which contains all the answers joined together in a single string, and then an attribute that is an array of question ids. There’s no relationship between the question ids and each answer.

A better approach would be to define an index on ProfileAnswer, and search via that instead - and then display the user for each ProfileAnswer in the search results.