use strict;
use warnings;
use XML::LibXML;

my $doc = XML::LibXML::Document->new();
my $root = $doc->createElement("views");
$doc->setDocumentElement($root);

while ( <DATA> )
{
    chomp;
    my ( $view_id, $view_name, $param_id, $param_name ) = split /\s+/, $_, 4;

    # find or create...
    my ( $view_node ) = $root->findnodes("//view[\@id=$view_id]");
    unless ( $view_node )
    {
        $view_node = $doc->createElement("view");
        $view_node->setAttribute("name",$view_name);
        $view_node->setAttribute("id",$view_id);
        $root->appendChild($view_node);
    }
    my $param_node = $doc->createElement("parameter");
    $param_node->setAttribute("id", $param_id);
    $param_name = $doc->createTextNode($param_name);
    $param_node->appendChild($param_name);
    $view_node->appendChild($param_node);
}

print $doc->serialize(1);

__DATA__
123456       all          123           Param 1
123456       all          124           Param 2
123457      detail        125           Param 3
123457      detail        126           Param 4
123457      detail        127           Param 5
123457      detail        128           Param 6