Designing good PHP quiz script.

Question

hi! I'm developing a quiz module for a school with php and mysql. The requirements are simple:

1) There are 10 categories(subjects).

2) Select 8 random questions from each category and display them one by one.

3) Get the students input.

4) Calculate the result and display it.

Now, the problem that i face is how to make the script as efficient as possible. Efficient in the sense, make less database hits. I want to store the 80 answers for that particular user in a place and then update them all at once in the DB. I don't want to use cookies. In what way can i achieve that?

Are there any simple php quiz modules that i can refer?

Thanks :)

Answer 1

If you have to show them one by one, you need to store the results somewhere and since http is stateless you have 2 choices: db or cookie. Now, in my opinion is better to store the answers in a cookie in a var like this

"a:1,b:2,question:answer,.."

and then explode them at the end and check the result.

Answer 2

You should not want that. It is perfectly normal for a webapp to store intermediate results in a database. Most apps do several database queries per page.

You could use sessions. This allows you to store data which is coupled to a user. However, session data is also stored somewhere, so efficiency is not a reason to store it in a session instead of a database.

Answer 3

You clearly want a fast cache layer. I suggest either memcached or APC for that purpose. Session data may also work.

That said, you'd probably be better off using a full-stack PHP framework for this. A good one will manage caches for you. I suggest looking into symfony or CakePHP.

Here's the real question, though: are you trying to address this problem up-front before you have established that there actually is a problem? This is a bad approach. Make sure you have a problem before you try to solve it.

Answer 4

From my personal point of view, if I'd be asked to design something similar, I would do the following:

• If I don't want to use database resources I'd have a "before starting quizz" step where I'd fetch my questions from the database
• Each user (even if not registered) has a unique session; the data fetched from the database would sit right there on the session (and because session is stored server side I wouldn't care for encrypting it)
• Session it's a bit problematic, though, but using the cookie and encrypting the data seems more work rather than making a longer session (maybe the students need some time to solve the quizz and a 5minute session would be a little low, but that's not a big problem, you can set it as you wish
• The answers are also stored on the session, at the end you just need to compare the results in the session with the answers in the session which is a pretty basic task: if the results are stored in a separate array, you could just call in_array() on each answer (the array being the correct results) and increment a variable to know how many questions are answered right (that works if every question has the same "value")

Enjoy!

Answer 5

What you want to do is a sort of wizard-style flow, with a Next button on each page. This is common to store the results in session for such things.

If you store the questions extracted randomly in session, like this :

$_SESSION['questions'] = array(
    array(
        'question'    => 'What is the response to life ?', 
        'answer'      => '42', 
        'user_answer' => null,   // Will contain the user answer
        'answered'    => false), // Will be set to true once the question is answered
    array(
        'question'    => 'What is the color of the sky ?',
        'answer'      => 'blue',
        'user_answer' => null, 
        'answered'    => false)
);

Then you could iterate over the questions, keeping trace of the answered questions.