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