Arthur Axel "fREW" Schmidt > DBIx-Class-Helpers-2.018001 > DBIx::Class::Helper::ResultSet::SearchOr

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Module Version: 2.018001   Source   Latest Release: DBIx-Class-Helpers-2.023006

NAME ^

DBIx::Class::Helper::ResultSet::SearchOr - Combine ResultSet searches with OR's

VERSION ^

version 2.018001

SYNOPSIS ^

 package MyApp::Schema::ResultSet::Tests;

 use base 'DBIx::Class::ResultSet';

 __PACKAGE__->load_components(qw(Helper::ResultSet::IgnoreWantarray Helper::ResultSet::SearchOr));

 sub failed {
   my $self = shift;

   my $me = $self->current_source_alias;

   $self->search({ "$me.passed" => '0' });
 }

 sub untested {
   my $self = shift;

   my $me = $self->current_source_alias;

   $self->search({ "$me.passed" => undef });
 }

 sub not_passed {
   my $self = shift;

   my $me = $self->current_source_alias;

   $self->search_or([$self->failed, $self->untested]);
 }

 1;

DESCRIPTION ^

I would argue that the most important feature of DBIx::Class is the fact that you can "chain" ResultSet searches. Unfortunately this can cause problems when you need to reuse multiple ResultSet methods as... well as or's. In the past I got around this by doing:

 $rs->foo->union([ $rs->bar]);

While this works, it can generate some hairy SQL pretty fast. This Helper is supposed to basically be a lightweight union. Note that it therefor has a number of "LIMITATIONS". The thing that makes this module special is that the ResultSet that is doing the "search_or" ing still limits everything correctly. To be clear, the following only returns $user's friends that match either of the following criteria:

 my $friend_rs = $schema->resultset('Friend');
 my @internet_friends = $user->friends->search_or([
   $friend_rs->on_facebook,
   $friend_rs->on_twitter,
 ])->all;

With a union, you'd have to implement it like this:

 $user->friends->on_facebook->union([ $user->friends->on_twitter ]);

The union will work, but it will generate more complex SQL that may have lower performance on your database.

See "NOTE" in DBIx::Class::Helper::ResultSet for a nice way to apply it to your entire schema.

METHODS ^

search_or

 my $new_rs = $rs->search_or([ $rs->foo, $rs->bar ]);

search_or takes a single arrayref of ResultSets. The ResultSets must point to the same source or you will get an error message. Additionally, no check is made to ensure that more than one ResultSet is in the ArrayRef, but only passing one ResultSet would not make any sense.

LIMITATIONS ^

Because this module us basically an expression union and not a true union, JOIN's won't Just Work. If you have a ResultSet method that uses a JOIN and you want to OR it with another method, you'll need to do something like this:

 my @authors = $authors->search(undef, { join => 'books' })->search_or([
    $authors->wrote_good_books,
    $authors->wrote_bestselling_books,
 ])->all;

Furthermore, if you want to OR two methods that JOIN in the same relationship via alternate paths you must use union.

AUTHOR ^

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

COPYRIGHT AND LICENSE ^

This software is copyright (c) 2013 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.

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