text: const mongoose = require('mongoose');
  
  const questionAnswerSchema = mongoose.Schema({
      _id: mongoose.Schema.Types.ObjectId,
      question_id: {
          type: Number,
          required: true
      },
      question_option_id: {
          type: Number,
          required: true
      },
      answer_time: {
          type: Number,
          required: true
      },
      student_id: {
          type: Number,
          required: true
      },
  });
  
  module.exports = mongoose.model('QuestionAnswer', questionAnswerSchema);