NAME
    DBIx::Class::ResultSet::RecursiveUpdate - like update_or_create - but
    recursive

SYNOPSIS
    The functional interface:

        my $new_item = DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update({ 
            resultset => $schema->resultset( 'Dvd' ),
            updates => {
                id => 1, 
                owned_dvds => [ 
                    { 
                      title => 'One Flew Over the Cuckoo's Nest' 
                    } 
                ] 
            }
        });

    As ResultSet subclass:

        __PACKAGE__->load_namespaces( default_resultset_class => '+DBIx::Class::ResultSet::RecursiveUpdate' );

    in the Schema file (see t/lib/DBSchema.pm). Or appriopriate 'use base'
    in the ResultSet classes.

    Then:

        my $user = $user_rs->recursive_update( { 
            id => 1, 
            owned_dvds => [ 
            { 
              title => 'One Flew Over the Cuckoo's Nest' 
            } 
            ] 
          }
        );

DESCRIPTION
This is still experimental. I've added a functional interface so that it can be used 
in Form Processors and not require modification of the model.
    You can feed the ->create method with a recursive datastructure and have
    the related records created. Unfortunately you cannot do a similar thing
    with update_or_create - this module tries to fill that void.

    It is a base class for ResultSets providing just one method:
    recursive_update which works just like update_or_create but can
    recursively update or create data objects composed of multiple rows. All
    rows need to be identified by primary keys - so you need to provide them
    in the update structure (unless they can be deduced from the parent row
    - for example when you have a belongs_to relationship). If not all
    colums comprising the primary key are specified - then a new row will be
    created, with the expectation that the missing columns will be filled by
    it (as in the case of auto_increment primary keys).

    If the resultset itself stores an assignement for the primary key, like
    in the case of:

        my $restricted_rs = $user_rs->search( { id => 1 } );

    then you need to inform recursive_update about additional predicate with
    a second argument:

        my $user = $restricted_rs->recursive_update( { 
            owned_dvds => [ 
            { 
              title => 'One Flew Over the Cuckoo's Nest' 
            } 
            ] 
          },
          [ 'id' ]
        );

    This will work with a new DBIC release.

    For a many_to_many (pseudo) relation you can supply a list of primary
    keys from the other table - and it will link the record at hand to those
    and only those records identified by them. This is convenient for
    handling web forms with check boxes (or a SELECT box with multiple
    choice) that let you update such (pseudo) relations.

    For a description how to set up base classes for ResultSets see
    load_namespaces in DBIx::Class::Schema.

DESIGN CHOICES
  Treatment of many to many pseudo relations
    The function gets the information about m2m relations from
    DBIx::Class::IntrospectableM2M. If it is not loaded in the ResultSource
    classes - then the code relies on the fact that: if($object->can($name)
    and !$object->result_source->has_relationship($name) and $object->can(
    'set_' . $name ) )

    then $name must be a many to many pseudo relation. And that in a
    similarly ugly was I find out what is the ResultSource of objects from
    that many to many pseudo relation.

INTERFACE
METHODS
  recursive_update
    The method that does the work here.

  is_m2m
    $self->is_m2m( 'name ' ) - answers the question if 'name' is a many to
    many (pseudo) relation on $self.

  get_m2m_source
    $self->get_m2m_source( 'name' ) - returns the ResultSource linked to by
    the many to many (pseudo) relation 'name' from $self.

DIAGNOSTICS
CONFIGURATION AND ENVIRONMENT
    DBIx::Class::RecursiveUpdate requires no configuration files or
    environment variables.

DEPENDENCIES
        DBIx::Class

INCOMPATIBILITIES
    None reported.

BUGS AND LIMITATIONS
    No bugs have been reported.

    Please report any bugs or feature requests to
    "bug-dbix-class-recursiveput@rt.cpan.org", or through the web interface
    at <http://rt.cpan.org>.

AUTHOR
    Zbigniew Lukasiak "<zby@cpan.org>" Influenced by code by Pedro Melo.

LICENCE AND COPYRIGHT
    Copyright (c) 2008, Zbigniew Lukasiak "<zby@cpan.org>". All rights
    reserved.

    This module is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself. See perlartistic.

DISCLAIMER OF WARRANTY
    BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
    FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
    OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
    PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
    EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
    ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
    YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
    NECESSARY SERVICING, REPAIR, OR CORRECTION.

    IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
    WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
    REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
    TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR
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    SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
    RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
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