NAME

DBIx::Class::ParameterizedJoinHack - Parameterized Relationship Joins

SYNOPSIS

#
#   The Result class we want to allow to join with a dynamic
#   condition.
#
package MySchema::Result::Person;
use base qw(DBIx::Class::Core);

__PACKAGE__->load_components(qw(ParameterizedJoinHack));
__PACKAGE__->table('person');
__PACKAGE__->add_columns(
    id => {
        data_type => 'integer',
        is_nullable => 0,
        is_auto_increment => 1,
    },
    name => {
        data_type => 'text',
        is_nullable => 0,
    }
);

...

__PACKAGE__->parameterized_has_many(
    priority_tasks => 'MySchema::Result::Task',
    [['min_priority'] => sub {
        my $args = shift;
        return +{
            "$args->{foreign_alias}.owner_id" => {
                -ident => "$args->{self_alias}.id",
            },
            "$args->{foreign_alias}.priority" => {
                '>=' => $_{min_priority},
            },
        };
    }],
);

1;

#
#   The ResultSet class belonging to your Result
#
package MySchema::ResultSet::Person;
use base qw(DBIx::Class::ResultSet);

__PACKAGE__->load_components(qw(ResultSet::ParameterizedJoinHack));

1;

#
#   A Result class to join against.
#
package MySchema::Result::Task;
use base qw(DBIx::Class::Core);

__PACKAGE__->table('task');
__PACKAGE__->add_columns(
    id => {
        data_type => 'integer',
        is_nullable => 0,
        is_auto_increment => 1,
    },
    owner_id => {
        data_type => 'integer',
        is_nullable => 0,
    },
    priority => {
        data_type => 'integer',
        is_nullable => 0,
    },
);

...

1;

#
#   Using the parameterized join.
#
my @urgent = MySchema
    ->connect(...)
    ->resultset('Person')
    ->with_parameterized_join(
        priority_tasks => {
            min_priority => 300,
        },
    )
    ->all;

WARNING

This module uses DBIx::Class internals and may break at any time.

DESCRIPTION

This DBIx::Class component allows to declare dynamically parameterized has-many relationships.

Add the component to your Result class as usual:

__PACKAGE__->load_components(qw( ParameterizedJoinHack ));

See "parameterized_has_many" for details on declaring relations.

See DBIx::Class::ResultSet::ParameterizedJoinHack for ResultSet usage.

Note: Currently only "parameterized_has_many" is implemented, since it is the most requested use-case. However, adding support for other relationship types is possible if a use-case is found.

METHODS

parameterized_has_many

__PACKAGE__->parameterized_has_many(
    $relation_name,
    $foreign_source,
    [\@join_arg_names, \&join_builder],
    $attrs,
);

The $relation_name, $foreign_source, and $attrs are passed through to has_many as usual. The third argument is an array reference containing an (array reference) list of argument names and a code reference used to build the join conditions.

The code reference will be called with the same arguments as if it had been passed to has_many directly, but the global %_ hash will contain the named arguments for the join.

See the "SYNOPSIS" for an example of a definition.

SPONSORS

Development of this module was sponsored by

• Ctrl O http://ctrlo.com

AUTHOR

Matt S. Trout <mst@shadowcat.co.uk>

CONTRIBUTORS

Robert Sedlacek <r.sedlacek@shadowcat.co.uk>

COPYRIGHT

Copyright (c) 2015 the DBIx::Class::ParameterizedJoinHack "AUTHOR" and "CONTRIBUTORS" as listed above.

LICENSE

This library is free software and may be distributed under the same terms as perl itself.