code: public function updateDb()
      {
          $this->printTaskInfo('Do database updates');
          $this->drush('updb');
          $drushVersion = $this->getVersion();
          if (-1 === version_compare($drushVersion, '6.0')) {
              $this->printTaskInfo('Will clear cache after db updates for drush '
                  . $drushVersion);
              $this->clearCache();
          } else {
              $this->printTaskInfo('Will not clear cache after db updates, since drush '
                  . $drushVersion . ' should do it automatically');
          }
  
          return $this;
      }
docs: Runs pending database updates.
  
  @return $this