Dynamic Granting of Insert Permissions?

I need to restrict insert permissions on a single table to a pre defined time window each day.

One way would be to craete a new user in NT and restrict login to the time window, and then only grant insert permissions on the table to this user.

better, though, would be to achieve this at DB level. Is this possible?Why would you ever need to do this at the DB level?

You might be able to set up a trigger to remove the inserted row after it is added if the time is in a range.

Better would be to have your application logic restrict access to the insert statement between certain times.