General Search in all tables of site

Controller.php

class Controller {
  public function search()
  {
      $kelime = $_POST['query'];

      $result   = $this->site_model->search($keyword);

      foreach ($result as $item) {
          switch ($item->type) {
              case 'products':
                  $item->id = site_url('products/' . $item->id);
                  break;
              case 'posts':
                  $item->id = site_url('posts/' . $item->id);
                  break;
              case 'services':
                  $item->id = site_url('services/' . $item->id);
                  break;
              case 'articles':
                  $item->id = site_url('articles/' . $item->id);
                  break;
          }
      }

      echo json_encode($result);
  }
}

Model.php

Class Model {
  public function search($keyword)
  {
      $query  = "
          SELECT
            id,
            urun_adi AS ad,
            'urun' AS type
          FROM en_urunler
          WHERE urun_adi LIKE ('%{$keyword}%')
          UNION ALL
          SELECT
            id,
            isim AS ad,
            'sayfa' AS type
          FROM en_sayfa
          WHERE isim LIKE ('%{$keyword}%')
          UNION ALL
          SELECT
            id,
            isim AS ad,
            'basinda' AS type
          FROM en_basinda
          WHERE isim LIKE ('%{$keyword}%')
      ";
      $result  = $this->db->query($query)->result();

      return $result;
  }
}