How to read data from json array in jquery?

I have to retrieve many rows from MySQL and send by encoding with ajax and I done this. but the problem is I am not able to handle the output array data in ajax. can anyone help me please?

1>one.php

<?php   



  $host = "localhost";
  $user = "root";
  $pass = "";

  $databaseName = "elearning";
  $tableName = "users";



    $con = mysql_connect($host,$user,$pass);
    $dbs = mysql_select_db($databaseName, $con);
    if(isset($_POST)){

                $exam_id=$_POST['exam_id'];
                $sql="select * from exam_to_question where exam_id=$exam_id";
                $result = mysql_query($sql);

                $dataArray = array();

                while($array = mysql_fetch_assoc($result)){
                    $dataArray[] = $array;
                } 

                echo json_encode($dataArray);
    }

?>

2> and ajax code is:

   $.ajax({    
      type: 'POST',
      url: '../functions/one.php',                          
      data: "exam_id="+exam_id,         
      dataType: 'json',
      success: function(data){


             //alert(data[0]['question_id']);
            // i have to handle data here 

            },
      error:function(){
    alert("AJAX failure");
        }   
    });