This is possibly a dumb question, but it has been triggered by a conversation I'm having with a colleague in our Dev team.
My understanding is that the 'Last Modified Date' of the MDF file (in Windows) is only changed when the Database is Closed/Reopened or data is written to the MDF file causing it to grow (eg. by a Full Backup or Transaction Log Backup, assuming database recovery mode is full)
However I've just noticed our hourly log backups are not changing the date of my .mdf files - they are stuck at the date/time of the last full backup. Shouldn't they be changing hourly for active databases?
What if there was no write activity captured in the log during that hour? Would it not affect the .mdf modified date? And if this is the case, would the modified date for readonly databases (databases that are defunct for write purposes but still used for read purposes) ever change?