Hi I just learning Catalyst and I got the following exception while i attempt to navigate to my url : http://localhost:3000/album I've created the following controller

package MusicApp::Controller::Album;
use Moose;
use namespace::autoclean;

BEGIN { extends 'Catalyst::Controller' }
    
sub base :Chained('/') :PathPart('album') :CaptureArgs(0) {
    my ($self, $c) = @_;
    $c->stash(resultset => $c->model('DB::Album'));
}

sub list :Chained('base') :PathPart('') :Args(0) {
    my ($self, $c) = @_;
    $c->stash(albums => [$c->stash->{resultset}->all]);
}

sub create :Chained('base') :PathPart('create') :Args(0) {
    my ($self, $c) = @_;
    
    if ($c->req->method eq 'POST') {
        my $album = $c->stash->{resultset}->create({
            title => $c->req->params->{title},
            artist => $c->req->params->{artist},
        });
        $c->response->redirect($c->uri_for($self->action_for('list')))
+;
    }
}

sub edit :Chained('base') :PathPart('edit') :Args(1) {
    my ($self, $c, $id) = @_;
    
    my $album = $c->stash->{resultset}->find($id);
    if ($c->req->method eq 'POST') {
        $album->update({
            title => $c->req->params->{title},
            artist => $c->req->params->{artist},
        });
        $c->response->redirect($c->uri_for($self->action_for('list')))
+;
    }
    $c->stash(album => $album);
}

sub delete :Chained('base') :PathPart('delete') :Args(1) {
    my ($self, $c, $id) = @_;
    
    my $album = $c->stash->{resultset}->find($id);
    $album->delete;
    $c->response->redirect($c->uri_for($self->action_for('list')));
}
1;
[download]

and created the ORM Entity Album :

# First, create the Models
# lib/MusicApp/Schema/Result/Album.pm
package MusicApp::Schema::Result::Album;
use strict;
use warnings;
use base qw/DBIx::Class::Core/;

__PACKAGE__->table('albums');
__PACKAGE__->add_columns(
    id => {
        data_type => 'integer',
        is_auto_increment => 1,
        is_nullable => 0,
    },
    title => {
        data_type => 'varchar',
        size => 128,
        is_nullable => 1,
    },
    artist => {
        data_type => 'varchar',
        size => 128,
        is_nullable => 1,
    },
);


__PACKAGE__->set_primary_key('id');
__PACKAGE__->has_many(album_songs => 'MusicApp::Schema::Result::AlbumS
+ong', 'album_id');
__PACKAGE__->many_to_many(songs => 'album_songs', 'song');
1;
[download]

And the Entity Song

package MusicApp::Schema::Result::Song;
use strict;
use warnings;
use base qw/DBIx::Class::Core/;

__PACKAGE__->table('songs');
__PACKAGE__->add_columns(
    id => {
        data_type => 'integer',
        is_auto_increment => 1,
        is_nullable => 0,
    },
    title => {
        data_type => 'varchar',
        size => 128,
        is_nullable => 1,
    },
    artist => {
        data_type => 'varchar',
        size => 128,
        is_nullable => 1,
    },
    length => {
        data_type => 'varchar',
        size => 16,
        is_nullable => 1,
    },
);

__PACKAGE__->set_primary_key('id');
__PACKAGE__->has_many(album_songs => 'MusicApp::Schema::Result::AlbumS
+ong', 'song_id');
__PACKAGE__->many_to_many(albums => 'album_songs', 'album');
1;
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And the relational table AlbumSong :

package MusicApp::Schema::Result::AlbumSong;
use strict;
use warnings;
use base qw/DBIx::Class::Core/;

__PACKAGE__->table('album_songs');
__PACKAGE__->add_columns(
    album_id => {
        data_type => 'integer',
        is_nullable => 0,
    },
    song_id => {
        data_type => 'integer',
        is_nullable => 0,
    },
);
__PACKAGE__->belongs_to(album => 'MusicApp::Schema::Result::Album', 'a
+lbum_id');
__PACKAGE__->belongs_to(song => 'MusicApp::Schema::Result::Song', 'son
+g_id');
1;  # Return true value at end of modules
[download]

I've created DB.pm file inside the directory MusicApp\Model\ folder (not sure if it's correct) :

package MusicApp::Model::DB;

use strict;
use base qw( Rose::DB );

__PACKAGE__->use_private_registry;

__PACKAGE__->register_db(
   domain   => __PACKAGE__->default_domain,
   type     => __PACKAGE__->default_type,
   driver   => 'sqlite',
   database => $ENV{DB_PATH} || 'mycrud.db',
);
1;

>/code>

My yaml config file 

<code>
---
abstract: 'Catalyst based application'
author:
  - 'Catalyst developer'
build_requires:
  ExtUtils::MakeMaker: 6.36
  Test::More: '0.88'
configure_requires:
  ExtUtils::MakeMaker: 6.36
distribution_type: module
dynamic_config: 1
generated_by: 'Module::Install version 1.21'
license: perl
meta-spec:
  url: http://module-build.sourceforge.net/META-spec-v1.4.html
  version: 1.4
name: MusicApp
no_index:
  directory:
    - inc
    - t
requires:
  Catalyst::Action::RenderView: 0
  Catalyst::Plugin::ConfigLoader: 0
  Catalyst::Plugin::Static::Simple: 0
  Catalyst::Runtime: '5.90132'
  Config::General: 0
  Moose: 0
  namespace::autoclean: 0
db_path: C:\MusicApp\script\music.db
resources:
  license: http://dev.perl.org/licenses/
version: '0.01'
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What can be wrong within this exception : Caught exception in MusicApp::Controller::Album->list "Can't call method "all" on an undefined value at C:\MusicApp\lib/MusicApp/Controller/Album.pm line 14." And that correspond to the following line of code :

    $c->stash(albums => [$c->stash->{resultset}->all]);
[download]