Quiz Module persistance implementation details

Question

In which part of the code is a new quiz stored in the database? What are the functions responsible for storing a new quiz in the database upon the submission of the form for creating a new quiz?

I'm trying to accomplish two things:

1. Timer per question
2. Dynamic question selection strategy

Quiz Module Version: 7.x-5.3

Answer 1

You need to be familiar with Drupal concepts like Nodes and Entities because they are used to model a Quiz.

The logic to keep the pieces synchronized is implemented via Hooks, like _hook_insert_ and _hook_update_, located on the quiz.module file.

Quiz 2.0 Architecture Information

A Quiz is a Drupal node, and thus the node table contains a row for each Quiz. Similarly, a Question is also a Drupal node, so it too has an entry in the node table. Additional properties for Quizzes can be found in the rows of the quiz_node_properties table. Similarly, all question-types have a table called quiz_node_question_properties to store additional data. Each question-type also makes it's own set of tables to hold answers and user feedback. That means the multichoice.module question-type gets a quiz_multichoice_answers and a quiz_multichoice_user_answers.

• From Community Documentation: Chapter 3 ~ Under The Hood

hook_insert

/**
 * Implements hook_insert().
 */
function quiz_insert($node) {
  // Need to set max_score if this is a cloned node.
  $max_score = 0;

  // Copy all the questions belonging to the quiz if this is a new translation.
  if ($node->is_new && isset($node->translation_source)) {
    quiz_copy_questions($node);
  }

  // Add references to all the questions belonging to the quiz if this is a
  // cloned quiz (node_clone compatibility).
  if ($node->is_new && isset($node->clone_from_original_nid)) {
    $old_quiz = node_load($node->clone_from_original_nid);

    $max_score = $old_quiz->max_score;

    $questions = quiz_get_questions($old_quiz->nid, $old_quiz->vid);

    quiz_set_questions($node, $questions);
  }

  _quiz_common_presave_actions($node);

  // If the quiz is saved as not randomized we have to make sure that questions
  // belonging to the quiz are saved as not random.
  _quiz_check_num_random($node);
  _quiz_check_num_always($node);

  quiz_update_defaults($node);
  _quiz_insert_resultoptions($node);
}

hook_update

/**
 * Implements hook_update().
 */
function quiz_update($node) {
  // Quiz node vid (revision) was updated.
  if (isset($node->revision) && $node->revision) {
    // Create new quiz-question relation entries in the quiz_node_relationship
    // table.
    quiz_update_quiz_question_relationship($node->old_vid, $node->vid, $node->nid);
    drupal_set_message(t('Some of the updated settings may not apply to quiz being taken already. To see all changes in action you need to start again.'), 'warning');
  }

  // Update an existing row in the quiz_node_properties table.
  _quiz_common_presave_actions($node);

  quiz_update_defaults($node);
  _quiz_update_resultoptions($node);

  _quiz_check_num_random($node);
  _quiz_check_num_always($node);
  quiz_update_max_score_properties(array($node->vid));
}