public static function drop() {
		foreach([
			"DROP VIEW IF EXISTS v_usess",
			"DROP TABLE IF EXISTS usess",
			"DROP TABLE IF EXISTS udata",
			"DROP TABLE IF EXISTS meta",
		] as $drop) {
			// @codeCoverageIgnoreStart
			try {
				self::$sql->query_raw($drop);
			} catch(SQLError $e) {
				$msg = "Cannot drop data:" . $e->getMessage();
				self::$logger->error("Zapmin: sql error: $msg");
				throw new AdminStoreError($msg);
			}
			// @codeCoverageIgnoreEnd
		}
	}