use strict;
use warnings;

package MySchema::Result::A;

use parent 'DBIx::Class::Core';

__PACKAGE__->table('a');

__PACKAGE__->add_columns( id => { data_type => 'INT', is_auto_increment => 1 } );

__PACKAGE__->set_primary_key('id');

__PACKAGE__->has_many( b => 'MySchema::Result::B' );

package MySchema::Result::B;

use parent 'DBIx::Class::Core';

__PACKAGE__->table('b');

__PACKAGE__->add_columns(
    id => { data_type => 'INT', is_auto_increment => 1 },
    a  => { data_type => 'INT' },
);

__PACKAGE__->set_primary_key('id');

__PACKAGE__->belongs_to( a => 'MySchema::Result::A' );

__PACKAGE__->has_many( c => 'MySchema::Result::C' );

package MySchema::Result::C;

use parent 'DBIx::Class::Core';

__PACKAGE__->table('c');

__PACKAGE__->add_columns(
    b => { data_type => 'INT' },
    x => { data_type => 'INT' },
);

__PACKAGE__->set_primary_key( 'b', 'x' );

__PACKAGE__->belongs_to( b => 'MySchema::Result::B' );

package MySchema;

use parent 'DBIx::Class::Schema';

__PACKAGE__->load_classes( { 'MySchema::Result' => [qw< A B C >] } );

package main;

my $schema = MySchema->connect('dbi:SQLite::memory:');

$schema->deploy();

my $a = $schema->resultset('A')->create( {} );
my $b = $a->create_related( b => {} );
$b->create_related( c => { x => 1000 + $_ } ) for 1 .. 3;

my $c = $a->search_related('b')->search_related('c');

$c->count();    # uses 1 level JOIN on table 'b'

$c->get_column('x')->all;    # uses 2 level JOIN on table 'c'

$c->delete();                # fetches and enumerates PKs

$b->search_related('c')->delete();    # 1st level relationship works as expected