Error number: 42p01/7 error: relation "news" does not exist line 2: from "news" ^ di ci

saya baru mengikuti tutorial CI di sekolah koding, tapi ada error ini

saya menggunakan database postgre ini strukture nya

$db['default'] = array(
	'dsn'	=> 'pgsql:host=localhost;port=5432;dbname=olshop',
	'hostname' => 'localhost',
	'username' => 'postgres',
	'password' => '****',
	'database' => 'ci',
	'dbdriver' => 'pdo',
);

ini controller nya

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class News extends CI_Controller {

  public function __construct(){
    parent::__construct();
    $this->load->model('news_model');
    $this->load->helper('url_helper');

  }

	public function index()
	{
    $data['news'] = $this->news_model->get_news();
    $data['title'] = 'Arsip berita';

		$this->load->view('news/index', $data);
	}
}

ini modelnya

<?php
class News_model extends CI_Model
{
  public function __construct()
  {
    $this->load->database();
  }
  public function get_news(){
    $query = $this->db->get('news');
    return $query->result_array();
  }
}

saya juga bingung penggunaan pdo dan mysqli di CI