如何使我的文本视图从会话中获取ID？

Question

我想在文本框中显示会话数据。我使用以下模型获取ID，并在下拉菜单中显示数据。但是我不知道如何从数据库中的会话中获取[id_dosen]。我该怎么办？

这是我的_dosen_model.php _：

public function getDosen(){
    $this->db->order_by('id_dosen','ASC');
    $dosen= $this->db->get('dosen');

    return $dosen->result_array();
}

这是我登录的控制器：

public function login() {
    $user       = $_POST['user'];
    $pass       = $_POST['pass'];
    $QuerySaya  = $this->db->query(
                    "SELECT * FROM user LEFT JOIN mahasiswa ON user.id_user=mahasiswa.id_user LEFT JOIN dosen ON user.id_user=dosen.id_user 
                    WHERE user.username='$user' AND user.password='$pass';"     
                );
    if ($QuerySaya->num_rows() == 0) {
        $this->load->view('login');
    } else {
        $data       = $QuerySaya->row();
        $this->session->set_userdata('id_admin_ti',             $data->id_user);
        $this->session->set_userdata('username',                $data->username);
        $this->session->set_userdata('password',                $data->password);
        $this->session->set_userdata('level_user',              $data->level_user);
        $this->session->set_userdata('id_kelas',                $data->id_kelas);   
        $this->session->set_userdata('id_dosen',                $data->id_dosen);
        $this->session->set_userdata('id_mhs',                  $data->id_mhs);
        $level = $this->session->userdata('level_user');
        if ($level == 'mahasiswa') {
            $this->load->view('dashboard_mhs', $data);
        }else if($level == 'admin'){
            $this->load->view('dashboard', $data);
        }else if($level == 'dosen'){
            $this->load->view('dashboard_dosen', $data);
        }
    }
}

这是我的观点：

<select id="dosen" name="dosen" class="required form-control input-xs" placeholder="Mata Kuliah" type="text" required="required">
    <option>-Nama Dosen-</option>
    <?php
        foreach ($dosen as $a) {
            echo "<option value=".$a['id_dosen'].">".$a['nama_dosen']."</option>";
        }
    ?>
</select>