use strict;
use warnings;

use DBI          qw( );
use Tree::Simple qw( );


{
    package Fruit;

    use Data::Dumper qw( Dumper );

    sub new { my $class = shift; bless({@_}, $class) }

    sub dump {
        my ($self, $prefix) = @_;

        local $Data::Dumper::Useqq    = 1;
        local $Data::Dumper::Terse    = 1;
        local $Data::Dumper::Indent   = 1;
        local $Data::Dumper::Pad      = $prefix;
        local $Data::Dumper::Sortkeys =
            sub{[qw( Parent Child Desc Property1 Property2 )]};

        return Dumper($self);
    }
}


sub treeify {
    my ($sth) = @_;

    my $tree = Tree::Simple->new(undef);

    my %children;
    while (my $row = $sth->fetchrow_hashref()) {
        my ($id, $parent_id) = @$row{qw( Child Parent )};

        my $parent = ( defined($parent_id)
            ? $children{$parent_id} ||= Tree::Simple->new(undef)
            : $tree
        );

        my $node = $children{$id} ||= Tree::Simple->new();
        $node->setNodeValue( Fruit->new(%$row) );
        $parent->addChild( $node );
    }

    return $tree;
}


sub dump_tree {
    my ($tree) = @_;

    $tree->traverse(sub {
        my ($node) = @_;
        my $prefix = "\t" x $node->getDepth();
        print( $node->getNodeValue()->dump( $prefix ) );
    });
}


{
    my $sponge = DBI->connect(
        'dbi:Sponge:', '', '',
        { RaiseError => 1 }
    );

    my $sth = $sponge->prepare(
        'SELECT * FROM Fruit',
        {
            NAME =>   [qw( Parent  Child  Desc             Property1  
+Property2        )],
            rows => [ [     undef,    50, 'Fruit',         'hidden',  
+'non-searchable'  ],
                      [        50,   100, 'Apple',         'hidden',  
+'non-searchable'  ],
                      [       100,   110, 'Granny Smith',  'Visible', 
+'searchable'      ],
            ],
        }
    );

    my $tree = treeify($sth);
    dump_tree($tree);
}
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