public function getSchedulingObjects($principalUri)
    {
        $stmt = $this->pdo->prepare('SELECT id, calendardata, uri, lastmodified, etag, size FROM '.$this->schedulingObjectTableName.' WHERE principaluri = ?');
        $stmt->execute([$principalUri]);

        $result = [];
        foreach ($stmt->fetchAll(\PDO::FETCH_ASSOC) as $row) {
            $result[] = [
                'calendardata' => $row['calendardata'],
                'uri' => $row['uri'],
                'lastmodified' => $row['lastmodified'],
                'etag' => '"'.$row['etag'].'"',
                'size' => (int) $row['size'],
            ];
        }

        return $result;
    }