my @db_values = split (/,/,$entry);
next unless ( @db_values == 7 ); ## add this line
$DB->sql("INSERT INTO Files ... ");
I don't see how that would work if the array is actually filled with undef's. For example...
steve@kirk:~$ perl -wle'push @foo, undef for (0..6); print scalar @foo
+'
7
Your code will only work if you don't have 7 entries in the array. It doesn't do any more checking of the data than that. More checks are needed to guarantee it will work.
A more appropriate question, though, is why the OP is not letting the database do the work for him? jhourcle's entry below suggesting a prepare is probably the best reply here. Let the database do the checks for NULL values then. Simply turning off warnings is not really solving the problem. It's a bit like using duct tape. Its a repair, but not a real fix. Also, there should be a performace boost by not having to repeatedly reparse the insert multiple times.
Also, regarding the question on an empty $ARGV[0] to open(). I did run into issues, but I had not problems with it die'ing. My problem is that $! wasn't getting populated without using strict on a one-liner. I will open a perlbug for this problem, but I could not see where open was failing to behave as expected. Hopefully, I can get a fix for my problem done this evening.
steve@kirk:~$ perl -wle'open FOO, undef || die "FOO! $!";'
Name "main::FOO" used only once: possible typo at -e line 1.
FOO! at -e line 1.
steve@kirk:~$ perl -Mstrict -wle'open FOO, undef || die "FOO! $!";'
Name "main::FOO" used only once: possible typo at -e line 1.
FOO! Bad file descriptor at -e line 1.