Question

I have a Django web application that’s similar to the typical Q&A system.

A user asks a question. other users submit answers to that question:

• Each user is allowed to submit up to N answers to each question,
  where N > 1 (so, say each user can submit no more than 3 answers to
  each question)
• A user can edit his existing answers, or submit new answer(s) if he
  hasn’t already reached his limit.

It’s straightforward to do this if each user is allowed only 1 answer
– just do:

unique_together = (("user.id", "question_id"),)

But in case of N>1, what is the best way to implement this?

Answer 1

I’d add the following method to your Question model:

class Question(models.Model):

    def can_answer(self, user):
        return Answer.filter(question=self, user=user).count() < 3

You can use this method to decide if a user can add answers to the question.