sub writeElems {
    my ($tbl, $prm, $dbh) = (shift, shift, shift);
            #table name, CGI object, DBI connection.
    my %valid = preinsert($prm, $tbl); #Creates the hash
    if (%valid) { $dbh->do(insertstr($tbl, %valid)); } #Creates and execs the statement
    return %valid;
}

##</code><code>##

# A sub to take CGI parameters, untaint and validate them.
# Returns: a hash with ready-to-insert data,
#          or undef if any field fails to validate or untaint;
# Arguments: A CGI object, the name of a table to prepare.

sub preinsert {
    my $page = shift;
    my $tbl = shift;
    my (%fields, %retval);

    foreach ($page->param) {
	if ($_ =~ /^$tbl\./) {
	    s/^($tbl\.)//;
	    $fields{$_} = $page->param("$tbl.$_");
	}
    }

#There's a table XML descriptor, and it's just fine.
    my $dsc = XMLin(M_LIB."/$tbl.descriptor", 
		    ForceArray => ['field']);

    foreach my $fieldref (keys %{$dsc->{field}}) {
	my %tags = %{$dsc->{field}->{$fieldref}};
	my $untaint;

	return undef if ($fields{$fieldref} !~ /$tags{untaint}/);
	$untaint = $1;
	print STDERR "recieved $1\n";
	if ($untaint =~ /$tags{validate}/) {
	    print STDERR "transmitted", ($retval{$fieldref} = $untaint), "\n";
	} else {
	    print STDERR "Invalid data";
	    return undef;
	}
    }
    return %retval;
}

##</code><code>##

# Prepares the insert statement string, using results of preinsert.
sub insertstr {
    my $tbl = shift;
    my %fields = @_;
    my $str = "insert into $tbl set";
    
    foreach (keys %fields) {print STDERR "$fields{$_}\n"; 
			    $str .= " $_=\'$fields{$_}\',";}
    
#watch this print:
    chop($str); print STDERR "$str\n";
    return $str.";";
}

##</code><code>##

if (scalar($page->param) > 1) {
    $Xtable = getXTableName($mtype, $dbh);
    $page->param('items.media_type', $mtype);

#This is it:
    writeElems('items', $page, $dbh);
    writeElems($Xtable, $page, $dbh) if $Xtable;

    $page->delete('items.media_type');
}