This is correct behaviour. The modified dates change when SQL Server closes the files (SQL Server shut down or the database is detached), or when the file is grown (either automatically or manually). All other times, SQL Server essentially bypasses the file system when performing the writes, and so the modified dates aren't updated.why?Assuming no fragmentation in the log file, the log is written to disk in a continuous fashion, and the disk head doesn't need to move. If you wanted the Modified datetime to be updated whenever the file is changed, the disk head would need to move to the position in the FAT where this value is stored and change it after each update, and then move back into position to write the next entry to the log.
说数据库的MDF和LDF文件更新时间