my @hdr = qw/title instructor inst_email active max_students
            description syllabus begin_date syll_name
            begin_time class_length/;
my @val = map "?", @hdr;
my @real_val = map{param($_)}@hdr;
my $sql;
{
   local $" = ',';
   $sql = "insert into class_info(@hdr) values (@val)";
}
my $sth = $dbh->prepare($sql);
$sth->execute(@real_val);