src/DrushStack.php
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;
    }
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;
    }
Runs pending database updates.

@return $this