Why doesn't the physical db file get updated?

I'm pretty sure there have been tons of transactions occurred in the past two working days (5/11 and 5/12) but I just found out our production db physical file is currently stamped with the Modified date of 5/10/2015 12:06 am. How could that happen? Does it mean the SQL hasn't written anything back to the physical db file in the past two days??
Can someone help me understand this? Thanks.
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

PadawanDBAOperational DBACommented:
I believe that the date modified attribute is updated on file close. so when the database is detached or the sql server service stops.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Scott PletcherSenior DBACommented:
Exactly.  It would be far too much overhead for the file/Windows time stamps to be constantly updated.

>>  Does it mean the SQL hasn't written anything back to the physical db file in the past two days?? <<

Thus, no; there could be many pages written back to the file during that time.
CastlewoodAuthor Commented:
So even the file is always used as long as the SQL db is up the Modified Date won't get updated till the db detached or sql service stops? Again, the file is always used, correct?
PadawanDBAOperational DBACommented:
When a database in SQL Server is online it is locked by the sql server process, yes.
Scott PletcherSenior DBACommented:
Typically, yes, unless AUTO_CLOSE is (mistakenly) set on.  That should never be set to on with non-Express dbs; you should change it to no if you ever see it as yes.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft SQL Server 2008

From novice to tech pro — start learning today.