DBIx::...Missing(3pm)

🌸 DBIx::Class::Helper::Row::OnColumnMissing 🌸

okay bestie, so this is a page from User Contributed Perl Documentation for DBIx::Class::Helper::Row::OnColumnMissing, and no, the module name isn't broken — the man page title is literally DBIx::...Missing(3pm) because long names are rude to terminal widths 💅

---

✨ NAME ✨

DBIx::Class::Helper::Row::OnColumnMissing — configurable handling for when you go reaching for a column that just… isn't there 🙈

---

🎀 SYNOPSIS 🎀

so you drop this into your Result class, like:

package MyApp::Schema::Result::Account;

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

__PACKAGE__->load_components(qw(Helper::Row::OnColumnMissing));

__PACKAGE__->table('Account');

__PACKAGE__->add_columns(
   id => {
      data_type         => 'integer',
      is_auto_increment => 1,
   },
   name => {
      data_type => 'varchar',
      size => 25,
   },
   book => { data_type => 'text' },
);

sub on_column_missing { 'die' }

1;

or, if you're a DBIx::Class::Candy girlie 🍓:

package MyApp::Schema::Result::Account;

use DBIx::Class::Candy -components => ['Helper::Row::OnColumnMissing'];

table 'Account';

column id => {
   data_type         => 'integer',
   is_auto_increment => 1,
};

column amount => {
   data_type          => 'float',
   keep_storage_value => 1,
};

column book => { data_type => 'text' };

sub on_column_missing { 'die' }

1;

and then somewhere else entirely:

my $row = $rs->search(undef, { columns => [qw( id name )] })->one_row;

$row->book # dies

yeah. $row->book just dies. dramatic? absolutely. correct? also yes 💀

---

🦋 DESCRIPTION 🦋

okay so here's the vibe: this module exists to handle that one specific cursed situation where you limited which columns got pulled from the database, and then you — or more likely future you — accidentally touched one of the ones you didn't grab. classic.

the way it works is fully configurable: you just tweak whatever the "on_column_missing" method returns. that's it. that's the whole knob. 👑

---

🌈 MODES 🌈

you pick your "mode" by returning that "mode" from the "on_column_missing" method. and the default "mode" it returns? that's "warn". so out of the box it's gonna yell at you, not end you.

the predefined modes are, in all their glory:

• "die" — dies with "Column $name has not been loaded"
• "warn" — warns with "Column $name has not been loaded"
• "nothing" — does nothing. literally nothing. iconic behaviour honestly

and bestie, you can go further: predefine more modes by defining methods named "on_column_$mode", and you can even override the default modes by overriding the corresponding methods. if you need something ad-hoc, just return a code reference and that gets called as a method on the object. slay ✨

💜 ADVANCED USAGE 💜

if for some reason you find that you need to change your "mode" at runtime — chaotic, but valid — you can always replace the "on_column_missing" with an accessor. for example:

__PACKAGE__->mk_group_accessors(inherited => 'on_column_missing');
__PACKAGE__->on_column_missing('warn');

and elsewhere:

$row->on_column_missing('die');

and if you are especially crazy you could even do something like this:

$row->on_column_missing(sub {
   my ($self, $column) = @_;

   $self
      ->result_source
      ->resultset
      ->search({ id => $self->id })
      ->get_column($column)
      ->single
});

though if you do that, I would make it a named mode. maybe "retrieve"? just a thought 🫶

---

🌸 THANKS 🌸

big love to ZipRecruiter <https://www.ziprecruiter.com> for funding the development of this module. paying for open source dev? that's main character energy fr fr 💖

---

👑 AUTHOR 👑

Arthur Axel "fREW" Schmidt <frioux+cpan@gmail.com>

---

🎀 COPYRIGHT AND LICENSE 🎀

This software is copyright (c) 2024 by Arthur Axel "fREW" Schmidt.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

---

and that's the whole page, bestie — no cap, every flag, mode, method and code snippet made it through intact. this one's from perl v5.40.0, dated 2024-11-16, and it's filed under that iconically truncated DBIx::...Missing(3pm) name. go forth and warn responsibly 💅✨