NAME

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

SYNOPSIS

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

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