Dogcows Code - chaz/p5-DBIx-Class-ResultSet-RecursiveUpdate/blob - lib/DBIx/Class/ResultSet/RecursiveUpdate.pm

   1 use strict;
   2 use warnings;
   3
   4 package DBIx::Class::ResultSet::RecursiveUpdate;
   5
   6 # ABSTRACT: like update_or_create - but recursive
   7
   8 use base qw(DBIx::Class::ResultSet);
   9
  10 sub recursive_update {
  11     my ( $self, $updates, $attrs ) = @_;
  12
  13     my $fixed_fields;
  14     my $unknown_params_ok;
  15
  16     # 0.21+ api
  17     if ( defined $attrs && ref $attrs eq 'HASH' ) {
  18         $fixed_fields      = $attrs->{fixed_fields};
  19         $unknown_params_ok = $attrs->{unknown_params_ok};
  20     }
  21
  22     # pre 0.21 api
  23     elsif ( defined $attrs && ref $attrs eq 'ARRAY' ) {
  24         $fixed_fields = $attrs;
  25     }
  26
  27     return
  28         DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update(
  29         resultset         => $self,
  30         updates           => $updates,
  31         fixed_fields      => $fixed_fields,
  32         unknown_params_ok => $unknown_params_ok,
  33         );
  34 }
  35
  36 package DBIx::Class::ResultSet::RecursiveUpdate::Functions;
  37 use Carp::Clan qw/^DBIx::Class|^HTML::FormHandler|^Try::Tiny/;
  38 use Scalar::Util qw( blessed );
  39 use List::MoreUtils qw/ any /;
  40
  41 sub recursive_update {
  42     my %params = @_;
  43     my ( $self, $updates, $fixed_fields, $object, $resolved,
  44         $if_not_submitted, $unknown_params_ok )
  45         = @params{
  46         qw/resultset updates fixed_fields object resolved if_not_submitted unknown_params_ok/
  47         };
  48     $resolved ||= {};
  49
  50     my $source = $self->result_source;
  51
  52     croak "first parameter needs to be defined"
  53         unless defined $updates;
  54
  55     croak "first parameter needs to be a hashref"
  56         unless ref($updates) eq 'HASH';
  57
  58     # warn 'entering: ' . $source->from();
  59     croak 'fixed fields needs to be an arrayref'
  60         if defined $fixed_fields && ref $fixed_fields ne 'ARRAY';
  61
  62     # always warn about additional parameters if storage debugging is enabled
  63     $unknown_params_ok = 0
  64         if $source->storage->debug;
  65
  66     if ( blessed($updates) && $updates->isa('DBIx::Class::Row') ) {
  67         return $updates;
  68     }
  69     if ( exists $updates->{id} ) {
  70
  71         # warn "finding object by id " . $updates->{id} . "\n";
  72         $object = $self->find( $updates->{id}, { key => 'primary' } );
  73
  74         # warn "object not found by id\n"
  75         #     unless defined $object;
  76     }
  77
  78     my %fixed_fields = map { $_ => 1 } @$fixed_fields
  79         if $fixed_fields;
  80     my @missing =
  81         grep { !exists $updates->{$_} && !exists $fixed_fields{$_} }
  82         $source->primary_columns;
  83     if ( !$object && !scalar @missing ) {
  84
  85         # warn 'finding by: ' . Dumper( $updates ); use Data::Dumper;
  86         $object = $self->find( $updates, { key => 'primary' } );
  87     }
  88     $updates = { %$updates, %$resolved };
  89     @missing =
  90         grep { !exists $resolved->{$_} } @missing;
  91     if ( !$object && !scalar @missing ) {
  92
  93         # warn 'finding by +resolved: ' . Dumper( $updates ); use Data::Dumper;
  94         $object = $self->find( $updates, { key => 'primary' } );
  95     }
  96
  97     $object = $self->new( {} )
  98         unless defined $object;
  99
 100     # warn Dumper( $updates ); use Data::Dumper;
 101     # direct column accessors
 102     my %columns;
 103
 104     # relations that that should be done before the row is inserted into the
 105     # database like belongs_to
 106     my %pre_updates;
 107
 108     # relations that that should be done after the row is inserted into the
 109     # database like has_many, might_have and has_one
 110     my %post_updates;
 111     my %other_methods;
 112     my %m2m_accessors;
 113     my %columns_by_accessor = _get_columns_by_accessor($self);
 114
 115     #    warn 'resolved: ' . Dumper( $resolved );
 116     #    warn 'updates: ' . Dumper( $updates ); use Data::Dumper;
 117     #    warn 'columns: ' . Dumper( \%columns_by_accessor );
 118     for my $name ( keys %$updates ) {
 119
 120         # columns
 121         if ( exists $columns_by_accessor{$name}
 122             && !( $source->has_relationship($name)
 123                 && ref( $updates->{$name} ) ) )
 124         {
 125
 126             #warn "$name is a column\n";
 127             $columns{$name} = $updates->{$name};
 128             next;
 129         }
 130
 131         # relationships
 132         if ( $source->has_relationship($name) ) {
 133             if ( _master_relation_cond( $self, $name ) ) {
 134
 135                 #warn "$name is a pre-update rel\n";
 136                 $pre_updates{$name} = $updates->{$name};
 137                 next;
 138             }
 139             else {
 140
 141                 #warn "$name is a post-update rel\n";
 142                 $post_updates{$name} = $updates->{$name};
 143                 next;
 144             }
 145         }
 146
 147         # many-to-many helper accessors
 148         if ( is_m2m( $self, $name ) ) {
 149
 150             #warn "$name is a many-to-many helper accessor\n";
 151             $m2m_accessors{$name} = $updates->{$name};
 152             next;
 153         }
 154
 155         # accessors
 156         if ( $object->can($name) && not $source->has_relationship($name) ) {
 157
 158             #warn "$name is an accessor";
 159             $other_methods{$name} = $updates->{$name};
 160             next;
 161         }
 162
 163         # unknown
 164
 165         # don't throw a warning instead of an exception to give users
 166         # time to adapt to the new API
 167         carp(
 168             "No such column, relationship, many-to-many helper accessor or generic accessor '$name'"
 169         ) unless $unknown_params_ok;
 170
 171 #$self->throw_exception(
 172 #    "No such column, relationship, many-to-many helper accessor or generic accessor '$name'"
 173 #);
 174     }
 175
 176     # warn 'other: ' . Dumper( \%other_methods ); use Data::Dumper;
 177
 178     # first update columns and other accessors
 179     # so that later related records can be found
 180     for my $name ( keys %columns ) {
 181
 182         #warn "update col $name\n";
 183         $object->$name( $columns{$name} );
 184     }
 185     for my $name ( keys %other_methods ) {
 186
 187         #warn "update other $name\n";
 188         $object->$name( $other_methods{$name} );
 189     }
 190     for my $name ( keys %pre_updates ) {
 191
 192         #warn "pre_update $name\n";
 193         _update_relation( $self, $name, $pre_updates{$name}, $object,
 194             $if_not_submitted );
 195     }
 196
 197     # $self->_delete_empty_auto_increment($object);
 198     # don't allow insert to recurse to related objects
 199     # do the recursion ourselves
 200     # $object->{_rel_in_storage} = 1;
 201     #warn "CHANGED: " . $object->is_changed . "\n";
 202     #warn "IN STOR: " .  $object->in_storage . "\n";
 203     $object->update_or_insert if $object->is_changed;
 204     $object->discard_changes;
 205
 206     # updating many_to_many
 207     for my $name ( keys %m2m_accessors ) {
 208         my $value = $m2m_accessors{$name};
 209
 210         #warn "update m2m $name\n";
 211         # TODO: only first pk col is used
 212         my ($pk) = _get_pk_for_related( $self, $name );
 213         my @rows = ();
 214         my $result_source = $object->$name->result_source;
 215         my @updates;
 216         if ( defined $value && ref $value eq 'ARRAY' ) {
 217             @updates = @{$value};
 218         }
 219         elsif ( defined $value && !ref $value ) {
 220             @updates = ($value);
 221         }
 222         else {
 223             carp "value of many-to-many rel '$name' must be an arrayref or scalar";
 224         }
 225         for my $elem (@updates) {
 226             if ( blessed($elem) && $elem->isa('DBIx::Class::Row') ) {
 227                 push @rows, $elem;
 228             }
 229             elsif ( ref $elem eq 'HASH' ) {
 230                 push @rows,
 231                     recursive_update(
 232                     resultset => $result_source->resultset,
 233                     updates   => $elem
 234                     );
 235             }
 236             else {
 237                 push @rows,
 238                     $result_source->resultset->find( { $pk => $elem } );
 239             }
 240         }
 241         my $set_meth = 'set_' . $name;
 242         $object->$set_meth( \@rows );
 243     }
 244     for my $name ( keys %post_updates ) {
 245
 246         #warn "post_update $name\n";
 247         _update_relation( $self, $name, $post_updates{$name}, $object,
 248             $if_not_submitted );
 249     }
 250     return $object;
 251 }
 252
 253 # returns DBIx::Class::ResultSource::column_info as a hash indexed by column accessor || name
 254 sub _get_columns_by_accessor {
 255     my $self   = shift;
 256     my $source = $self->result_source;
 257     my %columns;
 258     for my $name ( $source->columns ) {
 259         my $info = $source->column_info($name);
 260         $info->{name} = $name;
 261         $columns{ $info->{accessor} || $name } = $info;
 262     }
 263     return %columns;
 264 }
 265
 266 # Arguments: $rs, $name, $updates, $row, $if_not_submitted
 267 sub _update_relation {
 268     my ( $self, $name, $updates, $object, $if_not_submitted ) = @_;
 269
 270     # this should never happen because we're checking the paramters passed to
 271     # recursive_update, but just to be sure...
 272     $object->throw_exception("No such relationship '$name'")
 273         unless $object->has_relationship($name);
 274
 275     #warn "_update_relation $name: OBJ: " . ref($object) . "\n";
 276
 277     my $info = $object->result_source->relationship_info($name);
 278
 279     # get a related resultset without a condition
 280     my $related_resultset =
 281         $self->related_resultset($name)->result_source->resultset;
 282     my $resolved;
 283     if ( $self->result_source->can('_resolve_condition') ) {
 284         $resolved =
 285             $self->result_source->_resolve_condition( $info->{cond}, $name,
 286             $object );
 287     }
 288     else {
 289         $self->throw_exception(
 290             "result_source must support _resolve_condition");
 291     }
 292
 293     # warn "$name resolved: " . Dumper( $resolved ); use Data::Dumper;
 294     $resolved = {}
 295         if defined $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
 296             && $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
 297             == $resolved;
 298
 299     my @rel_cols = keys %{ $info->{cond} };
 300     map {s/^foreign\.//} @rel_cols;
 301
 302     #warn "REL_COLS: " . Dumper(@rel_cols); use Data::Dumper;
 303     #my $rel_col_cnt = scalar @rel_cols;
 304
 305     # find out if all related columns are nullable
 306     my $all_fks_nullable = 1;
 307     for my $rel_col (@rel_cols) {
 308         $all_fks_nullable = 0
 309             unless $related_resultset->result_source->column_info($rel_col)
 310                 ->{is_nullable};
 311     }
 312
 313     $if_not_submitted = $all_fks_nullable ? 'nullify' : 'delete'
 314         unless defined $if_not_submitted;
 315
 316     #warn "\tNULLABLE: $all_fks_nullable ACTION: $if_not_submitted\n";
 317
 318     #warn "RELINFO for $name: " . Dumper($info); use Data::Dumper;
 319
 320     # the only valid datatype for a has_many rels is an arrayref
 321     if ( $info->{attrs}{accessor} eq 'multi' ) {
 322
 323         # handle undef like empty arrayref
 324         $updates = []
 325             unless defined $updates;
 326         $self->throw_exception(
 327             "data for has_many relationship '$name' must be an arrayref")
 328             unless ref $updates eq 'ARRAY';
 329
 330         my @updated_objs;
 331
 332         #warn "\tupdating has_many rel '$name' ($rel_col_cnt columns cols)\n";
 333         for my $sub_updates ( @{$updates} ) {
 334             my $sub_object = recursive_update(
 335                 resultset => $related_resultset,
 336                 updates   => $sub_updates,
 337                 resolved  => $resolved
 338             );
 339
 340             push @updated_objs, $sub_object;
 341         }
 342
 343         #warn "\tcreated and updated related rows\n";
 344
 345         my @related_pks = $related_resultset->result_source->primary_columns;
 346
 347         my $rs_rel_delist = $object->$name;
 348
 349         # foreign table has a single pk column
 350         if ( scalar @related_pks == 1 ) {
 351             $rs_rel_delist = $rs_rel_delist->search_rs(
 352                 {   $related_pks[0] =>
 353                         { -not_in => [ map ( $_->id, @updated_objs ) ] }
 354                 }
 355             );
 356         }
 357
 358         # foreign table has multiple pk columns
 359         else {
 360             my @cond;
 361             for my $obj (@updated_objs) {
 362                 my %cond_for_obj;
 363                 for my $col (@related_pks) {
 364                     $cond_for_obj{$col} = $obj->get_column($col);
 365                 }
 366                 push @cond, \%cond_for_obj;
 367             }
 368
 369             # only limit resultset if there are related rows left
 370             if ( scalar @cond ) {
 371                 $rs_rel_delist =
 372                     $rs_rel_delist->search_rs( { -not => [@cond] } );
 373             }
 374         }
 375
 376         #warn "\tCOND: " . Dumper(\%cond);
 377         #my $rel_delist_cnt = $rs_rel_delist->count;
 378         if ( $if_not_submitted eq 'delete' ) {
 379
 380             #warn "\tdeleting related rows: $rel_delist_cnt\n";
 381             $rs_rel_delist->delete;
 382         }
 383         elsif ( $if_not_submitted eq 'set_to_null' ) {
 384
 385             #warn "\tnullifying related rows: $rel_delist_cnt\n";
 386             my %update = map { $_ => undef } @rel_cols;
 387             $rs_rel_delist->update( \%update );
 388         }
 389     }
 390     elsif ($info->{attrs}{accessor} eq 'single'
 391         || $info->{attrs}{accessor} eq 'filter' )
 392     {
 393
 394         #warn "\tupdating rel '$name': $if_not_submitted\n";
 395         my $sub_object;
 396         if ( ref $updates ) {
 397             if ( blessed($updates) && $updates->isa('DBIx::Class::Row') ) {
 398                 $sub_object = $updates;
 399             }
 400
 401             # for might_have relationship
 402             elsif ( $info->{attrs}{accessor} eq 'single'
 403                 && defined $object->$name )
 404             {
 405                 $sub_object = recursive_update(
 406                     resultset => $related_resultset,
 407                     updates   => $updates,
 408                     object    => $object->$name
 409                 );
 410             }
 411             else {
 412                 $sub_object = recursive_update(
 413                     resultset => $related_resultset,
 414                     updates   => $updates,
 415                     resolved  => $resolved
 416                 );
 417             }
 418         }
 419         else {
 420             $sub_object = $related_resultset->find($updates)
 421                 unless (
 422                 !$updates
 423                 && ( exists $info->{attrs}{join_type}
 424                     && $info->{attrs}{join_type} eq 'LEFT' )
 425                 );
 426         }
 427         $object->set_from_related( $name, $sub_object )
 428             unless (
 429                !$sub_object
 430             && !$updates
 431             && ( exists $info->{attrs}{join_type}
 432                 && $info->{attrs}{join_type} eq 'LEFT' )
 433             );
 434     }
 435     else {
 436         $self->throw_exception(
 437             "recursive_update doesn't now how to handle relationship '$name' with accessor "
 438                 . $info->{attrs}{accessor} );
 439     }
 440 }
 441
 442 sub is_m2m {
 443     my ( $self, $relation ) = @_;
 444     my $rclass = $self->result_class;
 445
 446     # DBIx::Class::IntrospectableM2M
 447     if ( $rclass->can('_m2m_metadata') ) {
 448         return $rclass->_m2m_metadata->{$relation};
 449     }
 450     my $object = $self->new( {} );
 451     if (    $object->can($relation)
 452         and !$self->result_source->has_relationship($relation)
 453         and $object->can( 'set_' . $relation ) )
 454     {
 455         return 1;
 456     }
 457     return;
 458 }
 459
 460 sub get_m2m_source {
 461     my ( $self, $relation ) = @_;
 462     my $rclass = $self->result_class;
 463
 464     # DBIx::Class::IntrospectableM2M
 465     if ( $rclass->can('_m2m_metadata') ) {
 466         return $self->result_source->related_source(
 467             $rclass->_m2m_metadata->{$relation}{relation} )
 468             ->related_source(
 469             $rclass->_m2m_metadata->{$relation}{foreign_relation} );
 470     }
 471     my $object = $self->new( {} );
 472     my $r = $object->$relation;
 473     return $r->result_source;
 474 }
 475
 476 sub _delete_empty_auto_increment {
 477     my ( $self, $object ) = @_;
 478     for my $col ( keys %{ $object->{_column_data} } ) {
 479         if ($object->result_source->column_info($col)->{is_auto_increment}
 480             and ( !defined $object->{_column_data}{$col}
 481                 or $object->{_column_data}{$col} eq '' )
 482             )
 483         {
 484             delete $object->{_column_data}{$col};
 485         }
 486     }
 487 }
 488
 489 sub _get_pk_for_related {
 490     my ( $self, $relation ) = @_;
 491     my $result_source;
 492     if ( $self->result_source->has_relationship($relation) ) {
 493         $result_source = $self->result_source->related_source($relation);
 494     }
 495
 496     # many to many case
 497     if ( is_m2m( $self, $relation ) ) {
 498         $result_source = get_m2m_source( $self, $relation );
 499     }
 500     return $result_source->primary_columns;
 501 }
 502
 503 # This function determines wheter a relationship should be done before or
 504 # after the row is inserted into the database
 505 # relationships before: belongs_to
 506 # relationships after: has_many, might_have and has_one
 507 # true means before, false after
 508 sub _master_relation_cond {
 509     my ( $self, $name ) = @_;
 510
 511     my $source = $self->result_source;
 512     my $info   = $source->relationship_info($name);
 513
 514     #warn "INFO: " . Dumper($info) . "\n";
 515
 516     # has_many rels are always after
 517     return 0
 518         if $info->{attrs}->{accessor} eq 'multi';
 519
 520     my @foreign_ids = _get_pk_for_related( $self, $name );
 521
 522     #warn "IDS: " . join(', ', @foreign_ids) . "\n";
 523
 524     my $cond = $info->{cond};
 525
 526     sub _inner {
 527         my ( $source, $cond, @foreign_ids ) = @_;
 528
 529         while ( my ( $f_key, $col ) = each %{$cond} ) {
 530
 531             # might_have is not master
 532             $col   =~ s/^self\.//;
 533             $f_key =~ s/^foreign\.//;
 534             if ( $source->column_info($col)->{is_auto_increment} ) {
 535                 return 0;
 536             }
 537             if ( any { $_ eq $f_key } @foreign_ids ) {
 538                 return 1;
 539             }
 540         }
 541         return 0;
 542     }
 543
 544     if ( ref $cond eq 'HASH' ) {
 545         return _inner( $source, $cond, @foreign_ids );
 546     }
 547
 548     # arrayref of hashrefs
 549     elsif ( ref $cond eq 'ARRAY' ) {
 550         for my $new_cond (@$cond) {
 551             return _inner( $source, $new_cond, @foreign_ids );
 552         }
 553     }
 554     else {
 555         $source->throw_exception(
 556             "unhandled relation condition " . ref($cond) );
 557     }
 558     return;
 559 }
 560
 561 1;    # Magic true value required at end of module
 562 __END__
 563
 564 =head1 SYNOPSIS
 565
 566     # The functional interface:
 567
 568     my $schema = MyDB::Schema->connect();
 569     my $new_item = DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update(
 570         resultset => $schema->resultset('User'),
 571         updates => {
 572             id => 1,
 573             owned_dvds => [
 574                 {
 575                     title => "One Flew Over the Cuckoo's Nest"
 576                 }
 577             ]
 578         },
 579         unknown_params_ok => 1,
 580     );
 581
 582
 583     # As ResultSet subclass:
 584
 585     __PACKAGE__->load_namespaces( default_resultset_class => '+DBIx::Class::ResultSet::RecursiveUpdate' );
 586
 587     # in the Schema file (see t/lib/DBSchema.pm).  Or appropriate 'use base' in the ResultSet classes.
 588
 589     my $user = $schema->resultset('User')->recursive_update({
 590         id => 1,
 591         owned_dvds => [
 592             {
 593                 title => "One Flew Over the Cuckoo's Nest"
 594             }
 595         ]
 596     }, {
 597         unknown_params_ok => 1,
 598     });
 599
 600     # You'll get a warning if you pass non-result specific data to
 601     # recursive_update. See L</"Additional data in the updates hashref">
 602     # for more information how to prevent this.
 603
 604 =head1 DESCRIPTION
 605
 606 This is still experimental.
 607
 608 You can feed the ->create method of DBIx::Class with a recursive datastructure
 609 and have the related records created. Unfortunately you cannot do a similar
 610 thing with update_or_create. This module tries to fill that void until
 611 L<DBIx::Class> has an api itself.
 612
 613 The functional interface can be used without modifications of the model,
 614 for example by form processors like L<HTML::FormHandler::Model::DBIC>.
 615
 616 It is a base class for L<DBIx::Class::ResultSet>s providing the method
 617 recursive_update which works just like update_or_create but can recursively
 618 update or create result objects composed of multiple rows. All rows need to be
 619 identified by primary keys so you need to provide them in the update structure
 620 (unless they can be deduced from the parent row. For example a related row of
 621 a belongs_to relationship). If any of the primary key columns are missing,
 622 a new row will be created, with the expectation that the missing columns will
 623 be filled by it (as in the case of auto_increment primary keys).
 624
 625 If the resultset itself stores an assignment for the primary key,
 626 like in the case of:
 627
 628     my $restricted_rs = $user_rs->search( { id => 1 } );
 629
 630 you need to inform recursive_update about the additional predicate with the fixed_fields attribute:
 631
 632     my $user = $restricted_rs->recursive_update( {
 633             owned_dvds => [
 634             {
 635                 title => 'One Flew Over the Cuckoo's Nest'
 636             }
 637             ]
 638         },
 639         {
 640             fixed_fields => [ 'id' ],
 641         }
 642     );
 643
 644 For a many_to_many (pseudo) relation you can supply a list of primary keys
 645 from the other table and it will link the record at hand to those and
 646 only those records identified by them. This is convenient for handling web
 647 forms with check boxes (or a select field with multiple choice) that lets you
 648 update such (pseudo) relations.
 649
 650 For a description how to set up base classes for ResultSets see
 651 L<DBIx::Class::Schema/load_namespaces>.
 652
 653 =head2 Additional data in the updates hashref
 654
 655 If you pass additional data to recursive_update which doesn't match a column
 656 name, column accessor, relationship or many-to-many helper accessor, it will
 657 throw a warning by default. To disable this behaviour you can set the
 658 unknown_params_ok attribute to a true value.
 659
 660 The warning thrown is:
 661 "No such column, relationship, many-to-many helper accessor or generic accessor '$key'"
 662
 663 When used by L<HTML::FormHandler::Model::DBIC> this can happen if you have
 664 additional form fields that aren't relevant to the database but don't have the
 665 noupdate attribute set to a true value.
 666
 667 NOTE: in a future version this behaviour will change and throw an exception
 668 instead of a warning!
 669
 670
 671 =head1 DESIGN CHOICES
 672
 673 Columns and relationships which are excluded from the updates hashref aren't
 674 touched at all.
 675
 676 =head2 Treatment of belongs_to relations
 677
 678 In case the relationship is included but undefined in the updates hashref,
 679 all columns forming the relationship will be set to null.
 680 If not all of them are nullable, DBIx::Class will throw an error.
 681
 682 Updating the relationship:
 683
 684     my $dvd = $dvd_rs->recursive_update( {
 685         id    => 1,
 686         owner => $user->id,
 687     });
 688
 689 Clearing the relationship (only works if cols are nullable!):
 690
 691     my $dvd = $dvd_rs->recursive_update( {
 692         id    => 1,
 693         owner => undef,
 694     });
 695
 696 =head2 Treatment of might_have relationships
 697
 698 In case the relationship is included but undefined in the updates hashref,
 699 all columns forming the relationship will be set to null.
 700
 701 Updating the relationship:
 702
 703     my $user = $user_rs->recursive_update( {
 704         id => 1,
 705         address => {
 706             street => "101 Main Street",
 707             city   => "Podunk",
 708             state  => "New York",
 709         }
 710     });
 711
 712 Clearing the relationship:
 713
 714     my $user = $user_rs->recursive_update( {
 715         id => 1,
 716         address => undef,
 717     });
 718
 719 =head2 Treatment of has_many relations
 720
 721 If a relationship key is included in the data structure with a value of undef
 722 or an empty array, all existing related rows will be deleted, or their foreign
 723 key columns will be set to null.
 724
 725 The exact behaviour depends on the nullability of the foreign key columns and
 726 the value of the "if_not_submitted" parameter. The parameter defaults to
 727 undefined which neither nullifies nor deletes.
 728
 729 When the array contains elements they are updated if they exist, created when
 730 not and deleted if not included.
 731
 732 =head3 All foreign table columns are nullable
 733
 734 In this case recursive_update defaults to nullifying the foreign columns.
 735
 736 =head3 Not all foreign table columns are nullable
 737
 738 In this case recursive_update deletes the foreign rows.
 739
 740 Updating the relationship:
 741
 742     Passing ids:
 743
 744     my $user = $user_rs->recursive_update( {
 745         id         => 1,
 746         owned_dvds => [1, 2],
 747     });
 748
 749     Passing hashrefs:
 750
 751     my $user = $user_rs->recursive_update( {
 752         id         => 1,
 753         owned_dvds => [
 754             {
 755                 name => 'temp name 1',
 756             },
 757             {
 758                 name => 'temp name 2',
 759             },
 760         ],
 761     });
 762
 763     Passing objects:
 764
 765     my $user = $user_rs->recursive_update( {
 766         id         => 1,
 767         owned_dvds => [ $dvd1, $dvd2 ],
 768     });
 769
 770     You can even mix them:
 771
 772     my $user = $user_rs->recursive_update( {
 773         id         => 1,
 774         owned_dvds => [ 1, { id => 2 } ],
 775     });
 776
 777 Clearing the relationship:
 778
 779     my $user = $user_rs->recursive_update( {
 780         id         => 1,
 781         owned_dvds => undef,
 782     });
 783
 784     This is the same as passing an empty array:
 785
 786     my $user = $user_rs->recursive_update( {
 787         id         => 1,
 788         owned_dvds => [],
 789     });
 790
 791 =head2 Treatment of many-to-many pseudo relations
 792
 793 If a many-to-many accessor key is included in the data structure with a value
 794 of undef or an empty array, all existing related rows are unlinked.
 795
 796 When the array contains elements they are updated if they exist, created when
 797 not and deleted if not included.
 798
 799 See L</is_m2m> for many-to-many pseudo relationship detection.
 800
 801 Updating the relationship:
 802
 803     Passing ids:
 804
 805     my $dvd = $dvd_rs->recursive_update( {
 806         id   => 1,
 807         tags => [1, 2],
 808     });
 809
 810     Passing hashrefs:
 811
 812     my $dvd = $dvd_rs->recursive_update( {
 813         id   => 1,
 814         tags => [
 815             {
 816                 id   => 1,
 817                 file => 'file0'
 818             },
 819             {
 820                 id   => 2,
 821                 file => 'file1',
 822             },
 823         ],
 824     });
 825
 826     Passing objects:
 827
 828     my $dvd = $dvd_rs->recursive_update( {
 829         id   => 1,
 830         tags => [ $tag1, $tag2 ],
 831     });
 832
 833     You can even mix them:
 834
 835     my $dvd = $dvd_rs->recursive_update( {
 836         id   => 1,
 837         tags => [ 2, { id => 3 } ],
 838     });
 839
 840 Clearing the relationship:
 841
 842     my $dvd = $dvd_rs->recursive_update( {
 843         id   => 1,
 844         tags => undef,
 845     });
 846
 847     This is the same as passing an empty array:
 848
 849     my $dvd = $dvd_rs->recursive_update( {
 850         id   => 1,
 851         tags => [],
 852     });
 853
 854
 855 =head1 INTERFACE
 856
 857 =head1 METHODS
 858
 859 =head2 recursive_update
 860
 861 The method that does the work here.
 862
 863 =head2 is_m2m
 864
 865 =over 4
 866
 867 =item Arguments: $name
 868
 869 =item Return Value: true, if $name is a many to many pseudo-relationship
 870
 871 =back
 872
 873 The function gets the information about m2m relations from
 874 L<DBIx::Class::IntrospectableM2M>. If it isn't loaded in the ResultSource
 875 class, the code relies on the fact:
 876
 877     if($object->can($name) and
 878              !$object->result_source->has_relationship($name) and
 879              $object->can( 'set_' . $name )
 880          )
 881
 882 to identify a many to many pseudo relationship. In a similar ugly way the
 883 ResultSource of that many to many pseudo relationship is detected.
 884
 885 So if you need many to many pseudo relationship support, it's strongly
 886 recommended to load L<DBIx::Class::IntrospectableM2M> in your ResultSource
 887 class!
 888
 889 =head2 get_m2m_source
 890
 891 =over 4
 892
 893 =item Arguments: $name
 894
 895 =item Return Value: $result_source
 896
 897 =back
 898
 899 =head1 CONFIGURATION AND ENVIRONMENT
 900
 901 DBIx::Class::RecursiveUpdate requires no configuration files or environment variables.
 902
 903 =head1 DEPENDENCIES
 904
 905     DBIx::Class
 906
 907 optional but recommended:
 908     DBIx::Class::IntrospectableM2M
 909
 910 =head1 INCOMPATIBILITIES
 911
 912 None reported.
 913
 914
 915 =head1 BUGS AND LIMITATIONS
 916
 917 The list of reported bugs can be viewed at L<http://rt.cpan.org/Public/Dist/Display.html?Name=DBIx-Class-ResultSet-RecursiveUpdate>.
 918
 919 Please report any bugs or feature requests to
 920 C<bug-dbix-class-recursiveput@rt.cpan.org>, or through the web interface at
 921 L<http://rt.cpan.org>.