将json数据插入CodeIgniter中的数据库

Question

我必须使用codeigniter将json数据插入数据库。但我有一些插入问题。

控制器

           $other_details=array($last_gradel,$years_studied,$school_name,$school_town,$school_district,$school_state,$school_country,
                          $school_tel_no,$school_mob_no,$school_email,$third_lang,$outstanding_achieve);     

        $application_insert = $this->career->insert_student_application($other_details);
        $status['result']  = "ok";
        echo json_encode($status);

模型

        function insert_student_application($other_details)
       {
            $data_insert = array(
            'applicant_prev_grade' => $other_details[0],
            'years_last_school' => $other_details[1],
            'school_name' => $other_details[2],
            'school_town' => $other_details[3],
            'school_district' => $other_details[4],
            'school_state' => $other_details[5],
            'school_country' => $other_details[6],
             'school_tel_number' => $other_details[7],
              'school_mob_number' => $other_details[8],
              'school_email_id' => $other_details[9],
               'third_language' => $other_details[10],
               'outstanding_achieve' => $other_details[11],
              'applicant_status' => 1,
              );
          $this->db->insert('student_application', $data_insert);
          return $this->db->last_query();
        }

** ajax *（以js为单位）

                      $.ajax({
                url: base_url+"admission/career_submit/",
                data: $('#career_submit_form').serialize(),//returns all cells' data
                dataType: 'json',
                type: 'POST',
                success: function (res) {
                  //  alert(res.result);
                    if (res.result === 'ok') {
                        window.scrollTo(0,0);
                    $("#succs_msg").css("display", "block"), 
                       window.setTimeout(function() { 
                            location.href=base_url+'admission' ;
                        }, 500);   
                    }
                    else {
                        alert("failed to save.Please Retry")
                    }
                },
                error: function (e) {
                    alert("function error") 
                    location.href=base_url+'admission' ; 
                }
            });

我在ajax函数之前获得了序列化数据。

现在我在ajax中收到错误函数错误。我在控制器中注释我的插入选项，然后显示成功消息。但我没有得到错误。