When working with CGI forms, I tend to farm the job out. Required fields, validation, etc. can get really painful if you have to deal with them manually - and pointless suffering is against my religion. :)

#!/usr/bin/perl -wT
use strict;
$|++;
use CGI::FormBuilder;
# Disable the next line for production
use CGI::Carp qw/warningsToBrowser fatalsToBrowser/;

my @fields = qw/name email zipcode/;
my @req = @fields[0, 1];                         ### These are the req
+uired fields
my %val = ( name => 'NAME', email => 'EMAIL' );  ### Validate via pre-
+defined methods

my $form = CGI::FormBuilder->new(method     =>   'post',
                                 fields     =>   \@fields,
                                 required   =>   \@req,
                                 validate   =>   \%val,
);

if ($form->submitted) {
    my $field = $form->fields;
    # update_db($field->fields};  # This is where you'd update the dat
+abase, etc.
    print $form->confirm(header => 1);
}
else {
    print $form->render(header => 1);
}
[download]

Be sure to take a look at the generated source. There's a lot going on behind the scenes.