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DBIx::Class::Helper::ResultSet::CorrelateRelationship(3pUser Contributed Perl DocumentatDBIx::Class::Helper::ResultSet::CorrelateRelationship(3pm)

NAME
DBIx::Class::Helper::ResultSet::CorrelateRelationship - Easily correlate your ResultSets VERSION
version 2.013002 SYNOPSIS
package MyApp::Schema::ResultSet::Author; use base 'DBIx::Class::ResultSet'; __PACKAGE__->load_components(qw(Helper::ResultSet::CorrelateRelationship)); sub with_book_count { my $self = shift; $self->search(undef, { '+columns' => { book_count => $self->correlate('book')->count_rs->as_query } }); } 1; And then elsewhere, like in a controller: my $rows = $schema->resultset('Author')->with_book_count->all; DESCRIPTION
Correlated queries are one of the coolest things I've learned about for SQL since my initial learning of SQL. Unfortunately they are somewhat confusing. DBIx::Class has supported doing them for a long time, but generally people don't think of them because they are so rare. I won't go through all the details of how they work and cool things you can do with them, but here are a couple high level things you can use them for to save you time or effort. If you want to select a list of authors and counts of books for each author, you could use "group_by" and something like "COUNT(book.id)", but then you'd need to make your select list match your "group_by" and it would just be a hassle forever after that. The "SYNOPSIS" is a perfect example of how to implement this. If you want to select a list of authors and two separate kinds of counts of books for each author, as far as I know, you must use a correlated subquery in DBIx::Class. Here is an example of how you might do that: package MyApp::Schema::ResultSet::Author; use base 'DBIx::Class::ResultSet'; __PACKAGE__->load_components(qw(Helper::ResultSet::CorrelateRelationship)); sub with_good_book_count { my $self = shift; $self->search(undef, { '+columns' => { good_book_count => $self->correlate('books')->good->count_rs->as_query } }); } sub with_bad_book_count { my $self = shift; $self->search(undef, { '+columns' => { bad_book_count => $self->correlate('books')->bad->count_rs->as_query } }); } 1; And then elsewhere, like in a controller: my $rows = $schema->resultset('Author') ->with_bad_book_count ->with_good_book_count ->all; This assumes that the Book resultset has "good" and "bad" methods. See "NOTE" in DBIx::Class::Helper::ResultSet for a nice way to apply it to your entire schema. METHODS
correlate $rs->correlate($relationship_name) Correlate takes a single argument, a relationship for the invocant, and returns a resultset that can be used in the selector list. AUTHOR
Arthur Axel "fREW" Schmidt <frioux+cpan@gmail.com> COPYRIGHT AND LICENSE
This software is copyright (c) 2012 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 v5.14.2 2012-06-18 DBIx::Class::Helper::ResultSet::CorrelateRelationship(3pm)

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DBIx::Class::Helper::Row::ProxyResultSetMethod(3pm)	User Contributed Perl Documentation    DBIx::Class::Helper::Row::ProxyResultSetMethod(3pm)

NAME
DBIx::Class::Helper::Row::ProxyResultSetMethod - Efficiently reuse ResultSet methods from results VERSION
version 2.013002 SYNOPSIS
ResultSet: package MyApp::Schema::ResultSet::Foo; use base 'DBIx::Class::ResultSet'; __PACKAGE__->load_components(qw( Helper::ResultSet::CorrelateRelationship )); ...; sub with_friend_count { shift->search(undef, { '+columns' => { 'friend_count' => $self->correlate('friends')->count_rs->as_query, }, }) } Result: package MyApp::Schema::Result::Foo; use base 'DBIx::Class::Core'; __PACKAGE__->load_components(qw( Helper::Row::ProxyResultSetMethod )); __PACKAGE__->proxy_resultset_method('friend_count'); or with DBIx::Class::Candy: package MyApp::Schema::Result::Foo; use DBIx::Class::Candy -components => ['Helper::Row::ProxyResultSetMethod']; proxy_resultset_method 'friend_count'; Elsewhere: my $row = $foo_rs->first; say $row->friend_count . ' friends'; DESCRIPTION
This module makes reusing resultset methods from a result trivially easy. You should be using it. METHODS
proxy_resultset_method __PACKAGE__->proxy_resultset_method( $name => { slot => $slot, resultset_method => $rs_method }); "proxy_resultset_method"'s first argument is the name of the method to generate and is required. The other two arguments, $slot, and $resultset_method are optional. If unspecified $slot will default to $name and $resultset_method will default to "with_$name". $slot is the column that the data being retrieved is stored as in the ResultSet method being proxied to. $resultset_method is (duh) the ResultSet method being proxied to. CANDY EXPORTS
If used in conjunction with DBIx::Class::Candy this component will export: proxy_resultset_method DEDICATION
This module is dedicated to Ray Bradbury, who wrote Something Wicked This Way Comes, Dandelion Wine, and numerous short stories, plays, etc etc. Read this author's books. AUTHOR
Arthur Axel "fREW" Schmidt <frioux+cpan@gmail.com> COPYRIGHT AND LICENSE
This software is copyright (c) 2012 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 v5.14.2 2012-06-18 DBIx::Class::Helper::Row::ProxyResultSetMethod(3pm)
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