In this situation, a Schwatzian Transformation is going to be necessary, as you'll need to have some way to convert from "HH:MM AP" to, say, a 24hr time. Assuming that the times are all within the same day, you can use hand coded stuff, but there are always modules like Date::Manip that will convert the time string to a epoch time.

But a simple starting point could be as follows:

sub time_to_2400 { 
   my $time = shift;
   my ( $hour, $min, $ap ) = ( $time =~ /^(\d{1,2}):(\d\d)\s([APM]{2})
+$/;
   $hour = 0 if $hour == 12;  #
   return ( $hour * 100 + $minute + ( ( $ap eq 'AM' ) ? 0 : 1200 ) );
}

my @sorted_list = 
    map { $database_in[ $$_[0] ] }
    sort { $$a[1] <=> $$b[1] }
    map { [ $_, time_to_2400( (split /\t/, $database_in[ $_ ])[4] ) ] 
+}
    (0..@database_in-1);
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Update and to the second part of the question, whenever new data is added to the database, given that you're using a flatfile, you can either run this sort again to get it into the right place, or better, read the flat file line by line and write to a new version of it, inserting the new item into the right place based on the time field, then write out the remaining part of the original flat file to the new file, and then move the new file over the old file when done.

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Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain