private function _commitObject($id, $revision)
    {
        $update = '';
        //if version tracking is disabled, delete previous revisions of the object
        if (!$this->_options->versionTracking) {
            $update .= Statement::get(
                'DELETE_OBJECT_EXCEPT_REVISION',
                [
                    '@collection' => $this->_name,
                    '@id' => $this->_connector->quote($id),
                    '@revision' => $this->_connector->quote($revision)
                ]
            );
        }
        $update .= Statement::get(
            'UPDATE_OBJECT_TO_COMMITTED',
            [
                '@collection' => $this->_name,
                '@id' => $this->_connector->quote($id),
                '@revision' => $this->_connector->quote($revision)
            ]
        );

        $this->_connector->exec($update);
    }