Zbigniew Łukasiak > DBIx-Class-ResultSet-RecursiveUpdate > DBIx::Class::ResultSet::RecursiveUpdate

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Module Version: 0.012   Source   Latest Release: DBIx-Class-ResultSet-RecursiveUpdate-0.34

NAME ^

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

VERSION ^

This document describes DBIx::Class::ResultSet::RecursiveUpdate version 0.006

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 CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

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