my %mappings_form2db = (
  # form  => db
  counter => 'count'          ,
  name    => 'name'           ,
  tel     => 'telephoneNumber',
);
my $cgi = CGI->new();
my %params = $cgi->Vars();
# hier dann die gueltigkeit ueberpruefen
# ...
# und dann das sql bauen:
my $sql = qq~INSERT INTO table (~
  . join (', ', values %mappings_form2db)
  . qq~) VALUES (~
  . join(', ', map { $dbh->quote($params{$_} ) } keys %mappings_form2db
  . ")";