londrum - 1:17 pm on Jul 31, 2013 (gmt 0)
if it only takes one minute to import it, and you get a new file every day, can't you just completely empty the database and re-import the new one?
if you don't want the site to be down for a minute then maybe you could have two identical databases (with different names). once you've imported the new file to the second database switch over which database your script connects to. then swap back and forth each day