how to show data from 3 combinational table using codeIgniter - php

Question

I have three database tables, question_set, question and answer.
question_set contains set_name and set_id
question contains question and also question_set_id
answer contains answer , question_id
I can not work out a way to show all the data in one view file,
I tried joins but then question data is repeating with it prints because every question has three or four answer.

Answer 1

Just thought I would point out.
Your database design is horrible.
It will not scale well, and infact I do not think it would actually. work.
The way I would do it is
Three tables
sets => id, name
questions => id, set_id, question
answers => id, set_id, question_id, answer, points
Note that in my above example I am taking it one step further, rather than each answer being true or false, it can have an assigned point value.
hence, an answer that you deemed half correct could be given 5 points, where as a correct answer could be given 10 points, it also works as a boolean true, just have a correct answer as 1 point, and an incorrect answer as 0 points
Anyway.
With the above table design in mind.
You could do
$this->db->select('s.id as set, s.name as name, q.id as qid, q.question as qu, a.id as aid, a.answer as an, a.points as p')
->from('sets s')
->join('questions q', 'q.set_id = s.id')
->join('answers a', 's.set_id = s.id')
->where('s.id', 'SET ID');
$questions = $this->db->get();
$set = array('questions' => array());
foreach($questions as $s){
$set['id'] = $s->set;
$set['name'] = $s->name;
$set['questions'][$s->qid]['id'] = $q->qid;
$set['questions'][$s->qid]['question'] = $q->qu;
if(!isset($set['questions'][$s->qid]['answers']))
$set['questions'][$s->qid]['answers'] = array();
$set['questions'][$s->qid]['answers'][] = array(
'id' => $q->aid,
'answer' => $q->an',
'points' => $q->p
);
}
So then you end up with an array that looks something like
array(
'id' => 1,
'name' => 'My first quiz',
'questions' = array(
array(
'id' => 1,
'question' => 'What is 1+1+1?',
'answers' => array(
array(
'id' => 1,
'answer' => 1,
'points' => 0
),
array(
'id' => 2,
'answer' => 2,
'points' => 0
),
array(
'id' => 3,
'answer' => 3,
'points' => 1
)
)
),
array(
'id' => 2,
'question' => 'What is 2+2+2?',
'answers' => array(
array(
'id' => 4,
'answer' => 6,
'points' => 1
),
array(
'id' => 5,
'answer' => 2,
'points' => 0
),
array(
'id' => 6,
'answer' => 3,
'points' => 0
)
)
)
)
);
Then you can do.
echo '<h2>'.$set['name'].'</h2>';
foreach($set['questions'] as $q){
echo '<div class="question">';
echo '<h3>'.$q['question'].'</h3>';
echo '<div class="answers">';
foreach($q['answers'] as $a){
echo '<label for="a'.$a['id'].'">'.$a['answer'].'<input type="checkbox value="'.$a['id'].'" name="q'.$q['id'].'" /></label><br />';
}
echo '</div>';
echo '</div>';
}

Answer 2

The easiest way, but which of course requires more SQL calls, is to use nested loops for this.
1) Join the question set and question tables
2) For each entry in the result set, retrieve the answers for that entry and put it in a separate array, nested in a bigger array where the key is the id of the question.
Your view would then look something like this:
foreach($questions as $question)
{
//Print question information
$answers = $answers_array[$question['id']];
foreach($answers as $answer)
{
//Print answers information
}
}
Might not be best practice but it will do the trick.