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.