Dogcows Code - chaz/p5-DBIx-Class-ResultSet-RecursiveUpdate/blob - README

   1 NAME
   2     DBIx::Class::ResultSet::RecursiveUpdate - like update_or_create - but
   3     recursive
   4
   5 VERSION
   6     This document describes DBIx::Class::ResultSet::RecursiveUpdate version
   7     0.006
   8
   9 SYNOPSIS
  10     The functional interface:
  11
  12         my $new_item = DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update({
  13             resultset => $schema->resultset( 'Dvd' ),
  14             updates => {
  15                 id => 1,
  16                 owned_dvds => [
  17                     {
  18                       title => 'One Flew Over the Cuckoo's Nest'
  19                     }
  20                 ]
  21             }
  22         });
  23
  24     As ResultSet subclass:
  25
  26         __PACKAGE__->load_namespaces( default_resultset_class => '+DBIx::Class::ResultSet::RecursiveUpdate' );
  27
  28     in the Schema file (see t/lib/DBSchema.pm). Or appriopriate 'use base'
  29     in the ResultSet classes.
  30
  31     Then:
  32
  33         my $user = $user_rs->recursive_update( {
  34             id => 1,
  35             owned_dvds => [
  36             {
  37               title => 'One Flew Over the Cuckoo's Nest'
  38             }
  39             ]
  40           }
  41         );
  42
  43 DESCRIPTION
  44 This is still experimental. I've added a functional interface so that it can be used
  45 in Form Processors and not require modification of the model.
  46     You can feed the ->create method with a recursive datastructure and have
  47     the related records created. Unfortunately you cannot do a similar thing
  48     with update_or_create - this module tries to fill that void.
  49
  50     It is a base class for ResultSets providing just one method:
  51     recursive_update which works just like update_or_create but can
  52     recursively update or create data objects composed of multiple rows. All
  53     rows need to be identified by primary keys - so you need to provide them
  54     in the update structure (unless they can be deduced from the parent row
  55     - for example when you have a belongs_to relationship). If not all
  56     colums comprising the primary key are specified - then a new row will be
  57     created, with the expectation that the missing columns will be filled by
  58     it (as in the case of auto_increment primary keys).
  59
  60     If the resultset itself stores an assignement for the primary key, like
  61     in the case of:
  62
  63         my $restricted_rs = $user_rs->search( { id => 1 } );
  64
  65     then you need to inform recursive_update about additional predicate with
  66     a second argument:
  67
  68         my $user = $restricted_rs->recursive_update( {
  69             owned_dvds => [
  70             {
  71               title => 'One Flew Over the Cuckoo's Nest'
  72             }
  73             ]
  74           },
  75           [ 'id' ]
  76         );
  77
  78     This will work with a new DBIC release.
  79
  80     For a many_to_many (pseudo) relation you can supply a list of primary
  81     keys from the other table - and it will link the record at hand to those
  82     and only those records identified by them. This is convenient for
  83     handling web forms with check boxes (or a SELECT box with multiple
  84     choice) that let you update such (pseudo) relations.
  85
  86     For a description how to set up base classes for ResultSets see
  87     load_namespaces in DBIx::Class::Schema.
  88
  89 DESIGN CHOICES
  90   Treatment of many to many pseudo relations
  91     The function gets the information about m2m relations from
  92     DBIx::Class::IntrospectableM2M. If it is not loaded in the ResultSource
  93     classes - then the code relies on the fact that: if($object->can($name)
  94     and !$object->result_source->has_relationship($name) and $object->can(
  95     'set_' . $name ) )
  96
  97     then $name must be a many to many pseudo relation. And that in a
  98     similarly ugly was I find out what is the ResultSource of objects from
  99     that many to many pseudo relation.
 100
 101 INTERFACE
 102 METHODS
 103   recursive_update
 104     The method that does the work here.
 105
 106   is_m2m
 107     $self->is_m2m( 'name ' ) - answers the question if 'name' is a many to
 108     many (pseudo) relation on $self.
 109
 110   get_m2m_source
 111     $self->get_m2m_source( 'name' ) - returns the ResultSource linked to by
 112     the many to many (pseudo) relation 'name' from $self.
 113
 114 DIAGNOSTICS
 115 CONFIGURATION AND ENVIRONMENT
 116     DBIx::Class::RecursiveUpdate requires no configuration files or
 117     environment variables.
 118
 119 DEPENDENCIES
 120         DBIx::Class
 121
 122 INCOMPATIBILITIES
 123     None reported.
 124
 125 BUGS AND LIMITATIONS
 126     No bugs have been reported.
 127
 128     Please report any bugs or feature requests to
 129     "bug-dbix-class-recursiveput@rt.cpan.org", or through the web interface
 130     at <http://rt.cpan.org>.
 131
 132 AUTHOR
 133     Zbigniew Lukasiak "<zby@cpan.org>" Influenced by code by Pedro Melo.
 134
 135 LICENCE AND COPYRIGHT
 136     Copyright (c) 2008, Zbigniew Lukasiak "<zby@cpan.org>". All rights
 137     reserved.
 138
 139     This module is free software; you can redistribute it and/or modify it
 140     under the same terms as Perl itself. See perlartistic.
 141
 142 DISCLAIMER OF WARRANTY
 143     BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
 144     FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
 145     OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
 146     PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
 147     EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 148     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
 149     ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
 150     YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
 151     NECESSARY SERVICING, REPAIR, OR CORRECTION.
 152
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