def _load_metadata(self):
        """Load metadata from the archive file"""

        logger.debug("Loading metadata infomation of archive %s", self.archive_path)

        cursor = self._db.cursor()
        select_stmt = "SELECT origin, backend_name, backend_version, " \
                      "category, backend_params, created_on " \
                      "FROM " + self.METADATA_TABLE + " " \
                      "LIMIT 1"
        cursor.execute(select_stmt)
        row = cursor.fetchone()
        cursor.close()

        if row:
            self.origin = row[0]
            self.backend_name = row[1]
            self.backend_version = row[2]
            self.category = row[3]
            self.backend_params = pickle.loads(row[4])
            self.created_on = str_to_datetime(row[5])
        else:
            logger.debug("Metadata of archive %s was empty", self.archive_path)

        logger.debug("Metadata of archive %s loaded", self.archive_path)
Load metadata from the archive file