如何解决错误编号：1048列'photo_pict'不能为空？

I got this error:

A Database Error Occurred
Error Number: 1048

Column 'photo_pict' cannot be null

    INSERT INTO `tester` (`photo_pict`, `press_pict`, `name_pict`) VALUES (NULL, NULL, NULL)

Filename: C:/xampp/htdocs/pretest/system/database/DB_driver.php

Line Number: 691

I'm using CodeIgniter and I'm a beginner programmer.

I was making a register form, all I have to do is just saving the input from the register form to the database. But every data has been saved to database except the data for saving photo to the database.

Code show here

Model :

function insert($data){
     $data = array(
        'first_name' => $data['first_name'],
        'last_name' => $data['last_name'],
        'birthDate' => $data['birthDate'],
        'gender' => $data['gender'],
        'posisi' => $data['posisi'],
        'media_name' => $data['media_name'],
        'media_region' => $data['media_region'],
        'media_ctgry' => $data['media_ctgry'],
        'company_addrss' => $data['company_addrss'],
        'website' => $data['website'],
        'editor_email' => $data['editor_email'],
        'office_phone' => $data['office_phone'],
        'office_fax' => $data['office_fax'],
        'personal_email' => $data['personal_email'],
        'phone_number' => $data['phone_number'],
        'working_email' => $data['working_email']
    );
    $this->db->insert('tester', $data);
}

    function upload($data){
     $gambar = array(
    'photo_pict'=> $data['photo_pict'],
    'press_pict'=> $data['press_pict'],
    'name_pict'=> $data['name_pict']
    );
    $this->db->insert('tester', $gambar);
}

    function proses_regist(){
    return $this->db->insert('tester', $data);
    }
}

My Controller :

public function __construct(){
    parent :: __construct();
    $this->load->model("Model_regist");
    $this->load->helper(array('url','form'));
}

public function index(){
    $this->load->view('home');
}

function register(){
    $gambar = array(
    'press_pict'=>$this->upload->data("photo_pict"),
    'photo_pict'=>$this->upload->data("press_pict"),
    'name_pict'=>$this->upload->data("name_pict")
    );

    $data = array(
        'first_name' => $this->input->post("first_name"),
        'last_name' => $this->input->post("last_name"),
        'birthDate' => $this->input->post("birthDate"),
        'gender' => $this->input->post("gender"),
        'posisi' => $this->input->post("posisi"),
        'media_name' => $this->input->post("media_name"),
        'media_region' => $this->input->post("media_region"),
        'media_ctgry' => $this->input->post("media_ctgry"),
        'company_addrss' => $this->input->post("company_addrss"),
        'website' => $this->input->post("website"),
        'editor_email' => $this->input->post("editor_email"),
        'office_phone' => $this->input->post("office_phone"),
        'office_fax' => $this->input->post("office_fax"),
        'personal_email' => $this->input->post("personal_email"),
        'phone_number' => $this->input->post("phone_number"),
        'working_email' => $this->input->post("working_email")
);
    $this->Model_regist->insert($data);
    $this->Model_regist->upload($gambar);
    $this->index();
}

private function uploadImage(){
    $config['upload_path']          = './gambar/';
    $config['allowed_types']        = 'gif|jpg|png';
    $config['file_name']            = $this->product_id;
    $config['max_size']             = 100;
    $config['max_width']            = 1024;
    $config['max_height']           = 768;
    $config['overwrite']             = true;
    $nama_file                   = "gambar_".time();
    $config['file_name']             = $nama_file;
    $this->load->library('upload', $config);

if( ! $this->upload->do_upload('berkas')){
    $error = array('error' => $this->upload->display_errors());
}else{
    $this->upload->data();
}
    $this->Model_regist->upload($gambar);
    $this->Model_regist->insert($data);
    $this->index();

}

I expect the photo that has been chosen can be saved in the database and can be saved in the file that I have made before. The file name is gambar.