public function updatePrincipal($path, DAV\PropPatch $propPatch)
    {
        $propPatch->handle(array_keys($this->fieldMap), function ($properties) use ($path) {
            $query = 'UPDATE '.$this->tableName.' SET ';
            $first = true;

            $values = [];

            foreach ($properties as $key => $value) {
                $dbField = $this->fieldMap[$key]['dbField'];

                if (!$first) {
                    $query .= ', ';
                }
                $first = false;
                $query .= $dbField.' = :'.$dbField;
                $values[$dbField] = $value;
            }

            $query .= ' WHERE uri = :uri';
            $values['uri'] = $path;

            $stmt = $this->pdo->prepare($query);
            $stmt->execute($values);

            return true;
        });
    }