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lib/App/DBCritic/Policy/DuplicateRelationships.pm  view on Meta::CPAN

package App::DBCritic::Policy::DuplicateRelationships;

# ABSTRACT: Check for ResultSources with unnecessary duplicate relationships

#pod =head1 SYNOPSIS
#pod
#pod     use App::DBCritic;
#pod
#pod     my $critic = App::DBCritic->new(
#pod         dsn => 'dbi:Oracle:HR', username => 'scott', password => 'tiger');
#pod     $critic->critique();
#pod
#pod =head1 DESCRIPTION
#pod
#pod This policy returns a violation if a
#pod L<DBIx::Class::ResultSource|DBIx::Class::ResultSource> has relationships to
#pod other tables that are identical in everything but name.
#pod
#pod =cut

use strict;
use utf8;
use Modern::Perl '2011';    ## no critic (Modules::ProhibitUseQuotedVersion)

our $VERSION = '0.023';     # VERSION
use Algorithm::Combinatorics 'combinations';
use Data::Compare;
use English '-no_match_vars';
use Moo;
use Sub::Quote;
use namespace::autoclean -also => qr{\A _}xms;

has description => (
    is      => 'ro',
    default => quote_sub q{'Duplicate relationships'},
);

#pod =attr description
#pod
#pod "Duplicate relationships"
#pod
#pod =cut

has explanation => (
    is      => 'ro',
    default => quote_sub
        q{'Each connection between tables should only be expressed once.'},
);

#pod =attr explanation
#pod
#pod "Each connection between tables should only be expressed once."
#pod
#pod =cut

sub violates {
    my $source = shift->element;
    return if $source->relationships < 2;

    return join "\n" => map { sprintf '%s and %s are duplicates', @{$_} }
        grep {
        Compare( map { $source->relationship_info($_) } @{$_} )
        } combinations( [ $source->relationships ], 2 );
}

#pod =method violates
#pod
#pod Returns details if the
#pod L<"current element"|App::DBCritic::Policy>'s C<relationship_info>
#pod hashes for any defined relationships are duplicated.
#pod
#pod =cut

with 'App::DBCritic::PolicyType::ResultSource';

#pod =attr applies_to
#pod
#pod This policy applies to L<ResultSource|DBIx::Class::ResultSource>s.
#pod
#pod =cut

1;

__END__

=pod

=encoding UTF-8

=for :stopwords Mark Gardner cpan testmatrix url annocpan anno bugtracker rt cpants
kwalitee diff irc mailto metadata placeholders metacpan

=head1 NAME

App::DBCritic::Policy::DuplicateRelationships - Check for ResultSources with unnecessary duplicate relationships

=head1 VERSION

version 0.023

=head1 SYNOPSIS

    use App::DBCritic;

    my $critic = App::DBCritic->new(
        dsn => 'dbi:Oracle:HR', username => 'scott', password => 'tiger');
    $critic->critique();

=head1 DESCRIPTION

This policy returns a violation if a
L<DBIx::Class::ResultSource|DBIx::Class::ResultSource> has relationships to
other tables that are identical in everything but name.

=head1 ATTRIBUTES

=head2 description

"Duplicate relationships"

=head2 explanation

"Each connection between tables should only be expressed once."

=head2 applies_to

This policy applies to L<ResultSource|DBIx::Class::ResultSource>s.

=head1 METHODS

=head2 violates

Returns details if the
L<"current element"|App::DBCritic::Policy>'s C<relationship_info>
hashes for any defined relationships are duplicated.

=head1 SUPPORT

=head2 Perldoc

You can find documentation for this module with the perldoc command.

  perldoc App::DBCritic::Policy::DuplicateRelationships

=head2 Websites

The following websites have more information about this module, and may be of help to you. As always,
in addition to those websites please use your favorite search engine to discover more resources.

=over 4

=item *

Search CPAN

The default CPAN search engine, useful to view POD in HTML format.

L<http://search.cpan.org/dist/App-DBCritic>

=item *

CPAN Ratings

The CPAN Ratings is a website that allows community ratings and reviews of Perl modules.

L<http://cpanratings.perl.org/d/App-DBCritic>