NAME

       DBIx::Class::Helper::Row::OnColumnMissing - Configurably handle access of missing columns

SYNOPSIS

        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 with DBIx::Class::Candy:

        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;

       Elsewhere:

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

        $row->book # dies

DESCRIPTION

       This module is written to handle the odd condition where you have limited the columns
       retrieved from the database but accidentally access one of the ones not included.  It is
       configurable by tweaking the "on_column_missing" return value.

MODES

       You specify the "mode" by returning the "mode" from the "on_column_missing" method.  By
       default the "mode" returned is "warn".

       The predefined modes are:

       "die"
         Dies with "Column $name has not been loaded".

       "warn"
         Warns with "Column $name has not been loaded".

       "nothing"
         Does nothing

       You can predefine more modes by defining methods named "on_column_$mode", and also
       override the default modes by overriding the corresponding methods.  If you need ad-hoc
       behavior you can return a code reference and that will be called as a method on the
       object.

   ADVANCED USAGE
       If for some reason you find that you need to change your "mode" at runtime, 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');

       Elsewhere:

        $row->on_column_missing('die');

       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"?)

THANKS

       Thanks ZipRecruiter <https://www.ziprecruiter.com> for funding the development of this
       module.

AUTHOR

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

COPYRIGHT AND LICENSE

       This software is copyright (c) 2015 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.

perl v5.20.2                                2015-11DBIx::Class::Helper::Row::OnColumnMissing(3pm)