Codeigniter query does not insert - php

Question

The data is being sent from the front end like this:
var data = {
'user_id':userid,
'qid':array[qnum].qid,
'user_ans':userAnswers[qnum].answer,
'user_time':userTime,
'exerciseid':exid,
'point_scored':points
};
$.post('<?php echo base_url()?>main/update_user_score',
{ myData : data },
function(result){} );
And in my "main" controller, I have:
$post_data = $_POST['myData'];
$data = array(
'user_id' => $post_data[user_id] ,
'qid' => $post_data[qid],
'user_ans' => $post_data[user_ans],
'user_time' => $post_data[user_time],
'exerciseid' => $post_data[exerciseid],
'point_scored' => $post_data[point_scored]
);
$this->load->model('Question_model','questions');
$this->questions->update_user_attempt($data);
In my Question_model / update_user_attempt:
error_log("data in model BEFORE INSERT:" . json_encode($data));
$this->db->insert('user_attempt', $data);
error_log("data in model AFTER INSERT: ");
The problem is, the data reaches (at least seems to me) the model quite fine. Here's the log entry:
[23-Apr-2012 16:04:47] data in model BEFORE INSERT:{"user_id":"5","qid":"3","user_ans":"d","user_time":"3","exerciseid":"cr1","point_scored":"35"}
BUT there is NO "after insert" log entry. The insert itself does not happen, and neither does the log entry after the insert.
I can read from the DB quite fine. So I checked in phpmyadmin the user privileges of the user in "config/database.php", and that user has ALL privileges, including INSERT.
So two questions:
What is the problem? What mistake am I making?
How do I even begin finding out what is going on with the insert statement? (I cannot find anything in the logs.)
I am looking at xampp/apache/logs/error.log and xampp/php/logs/php_error_log. Should I be looking at some other logs?

Answer 1

Try putting $this->db->_error_message(); after db insert
like this ...
error_log("data in model BEFORE INSERT:" . json_encode($data));
$this->db->insert('user_attempt', $data);
echo $this->db->_error_message();
error_log("data in model AFTER INSERT: ");

Answer 2

Aren't you missing this
$post_data['user_id']
Instead you are using without quotes

Answer 3

Don't forget to use $this->db->last_query() after your insert statement to see what the insert statement looks like. copy and paste that insert statement into your sql client to see if the query is actually working on its own.

Answer 4

Try adding
ini_set("display_errors", "1");
Also before your insert,
var_dump($data); die();
to see exactly what you are passing. Then check here to see that you are properly forming the insert statment.

Answer 5

First thing I thought was: shouldn't you use json_decode in stead of json_encode?
Did you set error_reporting(E_ALL);?