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 use Try::Tiny;
  41
  42 sub recursive_update {
  43     my %params = @_;
  44     my ( $self, $updates, $fixed_fields, $object, $resolved,
  45         $if_not_submitted, $unknown_params_ok )
  46         = @params{
  47         qw/resultset updates fixed_fields object resolved if_not_submitted unknown_params_ok/
  48         };
  49     $resolved ||= {};
  50
  51     my $source = $self->result_source;
  52
  53     croak "first parameter needs to be defined"
  54         unless defined $updates;
  55
  56     croak "first parameter needs to be a hashref"
  57         unless ref($updates) eq 'HASH';
  58
  59     # warn 'entering: ' . $source->from();
  60     croak 'fixed fields needs to be an arrayref'
  61         if defined $fixed_fields && ref $fixed_fields ne 'ARRAY';
  62
  63     # always warn about additional parameters if storage debugging is enabled
  64     $unknown_params_ok = 0
  65         if $source->storage->debug;
  66
  67     if ( blessed($updates) && $updates->isa('DBIx::Class::Row') ) {
  68         return $updates;
  69     }
  70
  71     if ( !defined $object && exists $updates->{id} ) {
  72
  73         # warn "finding object by id " . $updates->{id} . "\n";
  74         $object = $self->find( $updates->{id}, { key => 'primary' } );
  75
  76         # warn "object not found by id\n"
  77         #     unless defined $object;
  78     }
  79
  80     my %fixed_fields = map { $_ => 1 } @$fixed_fields
  81         if $fixed_fields;
  82
  83     # the updates hashref might contain the pk columns
  84     # but with an undefined value
  85     my @missing =
  86         grep { !defined $updates->{$_} && !exists $fixed_fields{$_} }
  87         $source->primary_columns;
  88
  89     # warn "MISSING: " . join(', ', @missing) . "\n";
  90     if ( !defined $object && scalar @missing == 0 ) {
  91
  92         # warn 'finding by: ' . Dumper( $updates ); use Data::Dumper;
  93         $object = $self->find( $updates, { key => 'primary' } );
  94     }
  95
  96     # add the resolved columns to the updates hashref
  97     $updates = { %$updates, %$resolved };
  98
  99     # the resolved hashref might contain the pk columns
 100     # but with an undefined value
 101     @missing = grep { !defined $resolved->{$_} } @missing;
 102
 103     #warn "MISSING2: " . join( ', ', @missing ) . "\n";
 104     if ( !defined $object && scalar @missing == 0 ) {
 105
 106        # warn 'finding by +resolved: ' . Dumper( $updates ); use Data::Dumper;
 107         $object = $self->find( $updates, { key => 'primary' } );
 108     }
 109
 110     $object = $self->new_result( {} )
 111         unless defined $object;
 112
 113     # warn Dumper( $updates ); use Data::Dumper;
 114     # direct column accessors
 115     my %columns;
 116
 117     # relations that that should be done before the row is inserted into the
 118     # database like belongs_to
 119     my %pre_updates;
 120
 121     # relations that that should be done after the row is inserted into the
 122     # database like has_many, might_have and has_one
 123     my %post_updates;
 124     my %other_methods;
 125     my %m2m_accessors;
 126     my %columns_by_accessor = _get_columns_by_accessor($self);
 127
 128     #    warn 'resolved: ' . Dumper( $resolved );
 129     #    warn 'updates: ' . Dumper( $updates ); use Data::Dumper;
 130     #    warn 'columns: ' . Dumper( \%columns_by_accessor );
 131     for my $name ( keys %$updates ) {
 132
 133         # columns
 134         if ( exists $columns_by_accessor{$name}
 135             && !( $source->has_relationship($name)
 136                 && ref( $updates->{$name} ) ) )
 137         {
 138
 139             #warn "$name is a column\n";
 140             $columns{$name} = $updates->{$name};
 141             next;
 142         }
 143
 144         # relationships
 145         if ( $source->has_relationship($name) ) {
 146             if ( _master_relation_cond( $self, $name ) ) {
 147
 148                 #warn "$name is a pre-update rel\n";
 149                 $pre_updates{$name} = $updates->{$name};
 150                 next;
 151             }
 152             else {
 153
 154                 #warn "$name is a post-update rel\n";
 155                 $post_updates{$name} = $updates->{$name};
 156                 next;
 157             }
 158         }
 159
 160         # many-to-many helper accessors
 161         if ( is_m2m( $self, $name ) ) {
 162
 163             #warn "$name is a many-to-many helper accessor\n";
 164             $m2m_accessors{$name} = $updates->{$name};
 165             next;
 166         }
 167
 168         # accessors
 169         if ( $object->can($name) && not $source->has_relationship($name) ) {
 170
 171             #warn "$name is an accessor";
 172             $other_methods{$name} = $updates->{$name};
 173             next;
 174         }
 175
 176         # unknown
 177
 178         # don't throw a warning instead of an exception to give users
 179         # time to adapt to the new API
 180         carp(
 181             "No such column, relationship, many-to-many helper accessor or generic accessor '$name'"
 182         ) unless $unknown_params_ok;
 183
 184 #$self->throw_exception(
 185 #    "No such column, relationship, many-to-many helper accessor or generic accessor '$name'"
 186 #);
 187     }
 188
 189     # warn 'other: ' . Dumper( \%other_methods ); use Data::Dumper;
 190
 191     # first update columns and other accessors
 192     # so that later related records can be found
 193     for my $name ( keys %columns ) {
 194
 195         #warn "update col $name\n";
 196         $object->$name( $columns{$name} );
 197     }
 198     for my $name ( keys %other_methods ) {
 199
 200         #warn "update other $name\n";
 201         $object->$name( $other_methods{$name} );
 202     }
 203     for my $name ( keys %pre_updates ) {
 204
 205         #warn "pre_update $name\n";
 206         _update_relation( $self, $name, $pre_updates{$name}, $object,
 207             $if_not_submitted );
 208     }
 209
 210     # $self->_delete_empty_auto_increment($object);
 211     # don't allow insert to recurse to related objects
 212     # do the recursion ourselves
 213     # $object->{_rel_in_storage} = 1;
 214     #warn "CHANGED: " . $object->is_changed . "\n";
 215     #warn "IN STOR: " .  $object->in_storage . "\n";
 216     $object->update_or_insert if $object->is_changed;
 217     $object->discard_changes;
 218
 219     # updating many_to_many
 220     for my $name ( keys %m2m_accessors ) {
 221         my $value = $m2m_accessors{$name};
 222
 223         #warn "update m2m $name\n";
 224         # TODO: only first pk col is used
 225         my ($pk) = _get_pk_for_related( $self, $name );
 226         my @rows;
 227         my $result_source = $object->$name->result_source;
 228         my @updates;
 229         if ( defined $value && ref $value eq 'ARRAY' ) {
 230             @updates = @{$value};
 231         }
 232         elsif ( defined $value && !ref $value ) {
 233             @updates = ($value);
 234         }
 235         elsif ( defined $value ) {
 236             carp
 237                 "value of many-to-many rel '$name' must be an arrayref or scalar: $value";
 238         }
 239         for my $elem (@updates) {
 240             if ( blessed($elem) && $elem->isa('DBIx::Class::Row') ) {
 241                 push @rows, $elem;
 242             }
 243             elsif ( ref $elem eq 'HASH' ) {
 244                 push @rows,
 245                     recursive_update(
 246                     resultset => $result_source->resultset,
 247                     updates   => $elem
 248                     );
 249             }
 250             else {
 251                 push @rows,
 252                     $result_source->resultset->find( { $pk => $elem } );
 253             }
 254         }
 255         my $set_meth = 'set_' . $name;
 256         $object->$set_meth( \@rows );
 257     }
 258     for my $name ( keys %post_updates ) {
 259
 260         #warn "post_update $name\n";
 261         _update_relation( $self, $name, $post_updates{$name}, $object,
 262             $if_not_submitted );
 263     }
 264     return $object;
 265 }
 266
 267 # returns DBIx::Class::ResultSource::column_info as a hash indexed by column accessor || name
 268 sub _get_columns_by_accessor {
 269     my $self   = shift;
 270     my $source = $self->result_source;
 271     my %columns;
 272     for my $name ( $source->columns ) {
 273         my $info = $source->column_info($name);
 274         $info->{name} = $name;
 275         $columns{ $info->{accessor} || $name } = $info;
 276     }
 277     return %columns;
 278 }
 279
 280 # Arguments: $rs, $name, $updates, $row, $if_not_submitted
 281 sub _update_relation {
 282     my ( $self, $name, $updates, $object, $if_not_submitted ) = @_;
 283
 284     # this should never happen because we're checking the paramters passed to
 285     # recursive_update, but just to be sure...
 286     $object->throw_exception("No such relationship '$name'")
 287         unless $object->has_relationship($name);
 288
 289     #warn "_update_relation $name: OBJ: " . ref($object) . "\n";
 290
 291     my $info = $object->result_source->relationship_info($name);
 292
 293     # get a related resultset without a condition
 294     my $related_resultset =
 295         $self->related_resultset($name)->result_source->resultset;
 296     my $resolved;
 297     if ( $self->result_source->can('_resolve_condition') ) {
 298         $resolved =
 299             $self->result_source->_resolve_condition( $info->{cond}, $name,
 300             $object );
 301     }
 302     else {
 303         $self->throw_exception(
 304             "result_source must support _resolve_condition");
 305     }
 306
 307     # warn "$name resolved: " . Dumper( $resolved ); use Data::Dumper;
 308     $resolved = {}
 309         if defined $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
 310             && $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
 311             == $resolved;
 312
 313     #warn "RESOLVED: " . Dumper($resolved); use Data::Dumper;
 314
 315     my @rel_cols = keys %{ $info->{cond} };
 316     map {s/^foreign\.//} @rel_cols;
 317
 318     #warn "REL_COLS: " . Dumper(@rel_cols); use Data::Dumper;
 319     #my $rel_col_cnt = scalar @rel_cols;
 320
 321     # find out if all related columns are nullable
 322     my $all_fks_nullable = 1;
 323     for my $rel_col (@rel_cols) {
 324         $all_fks_nullable = 0
 325             unless $related_resultset->result_source->column_info($rel_col)
 326                 ->{is_nullable};
 327     }
 328
 329     $if_not_submitted = $all_fks_nullable ? 'set_to_null' : 'delete'
 330         unless defined $if_not_submitted;
 331
 332     #warn "\tNULLABLE: $all_fks_nullable ACTION: $if_not_submitted\n";
 333
 334     #warn "RELINFO for $name: " . Dumper($info); use Data::Dumper;
 335
 336     # the only valid datatype for a has_many rels is an arrayref
 337     if ( $info->{attrs}{accessor} eq 'multi' ) {
 338
 339         # handle undef like empty arrayref
 340         $updates = []
 341             unless defined $updates;
 342         $self->throw_exception(
 343             "data for has_many relationship '$name' must be an arrayref")
 344             unless ref $updates eq 'ARRAY';
 345
 346         my @updated_objs;
 347
 348         #warn "\tupdating has_many rel '$name' ($rel_col_cnt columns cols)\n";
 349         for my $sub_updates ( @{$updates} ) {
 350             my $sub_object = recursive_update(
 351                 resultset => $related_resultset,
 352                 updates   => $sub_updates,
 353                 resolved  => $resolved
 354             );
 355
 356             push @updated_objs, $sub_object;
 357         }
 358
 359         #warn "\tcreated and updated related rows\n";
 360
 361         my @related_pks = $related_resultset->result_source->primary_columns;
 362
 363         my $rs_rel_delist = $object->$name;
 364
 365         # foreign table has a single pk column
 366         if ( scalar @related_pks == 1 ) {
 367             $rs_rel_delist = $rs_rel_delist->search_rs(
 368                 {   $related_pks[0] =>
 369                         { -not_in => [ map ( $_->id, @updated_objs ) ] }
 370                 }
 371             );
 372         }
 373
 374         # foreign table has multiple pk columns
 375         else {
 376             my @cond;
 377             for my $obj (@updated_objs) {
 378                 my %cond_for_obj;
 379                 for my $col (@related_pks) {
 380                     $cond_for_obj{$col} = $obj->get_column($col);
 381                 }
 382                 push @cond, \%cond_for_obj;
 383             }
 384
 385             # only limit resultset if there are related rows left
 386             if ( scalar @cond ) {
 387                 $rs_rel_delist =
 388                     $rs_rel_delist->search_rs( { -not => [@cond] } );
 389             }
 390             #warn "\tCOND: " . Dumper(\@cond);
 391         }
 392
 393         #my $rel_delist_cnt = $rs_rel_delist->count;
 394         if ( $if_not_submitted eq 'delete' ) {
 395
 396             #warn "\tdeleting related rows: $rel_delist_cnt\n";
 397             $rs_rel_delist->delete;
 398         }
 399         elsif ( $if_not_submitted eq 'set_to_null' ) {
 400
 401             #warn "\tnullifying related rows: $rel_delist_cnt\n";
 402             my %update = map { $_ => undef } @rel_cols;
 403             $rs_rel_delist->update( \%update );
 404         }
 405     }
 406     elsif ($info->{attrs}{accessor} eq 'single'
 407         || $info->{attrs}{accessor} eq 'filter' )
 408     {
 409
 410         #warn "\tupdating rel '$name': $if_not_submitted\n";
 411         my $sub_object;
 412         if ( ref $updates ) {
 413             if ( blessed($updates) && $updates->isa('DBIx::Class::Row') ) {
 414                 $sub_object = $updates;
 415             }
 416
 417             # for might_have relationship
 418             elsif ( $info->{attrs}{accessor} eq 'single'
 419                 && defined $object->$name )
 420             {
 421                 $sub_object = recursive_update(
 422                     resultset => $related_resultset,
 423                     updates   => $updates,
 424                     object    => $object->$name
 425                 );
 426             }
 427             else {
 428                 $sub_object = recursive_update(
 429                     resultset => $related_resultset,
 430                     updates   => $updates,
 431                     resolved  => $resolved
 432                 );
 433             }
 434         }
 435         else {
 436             $sub_object = $related_resultset->find($updates)
 437                 unless (
 438                 !$updates
 439                 && ( exists $info->{attrs}{join_type}
 440                     && $info->{attrs}{join_type} eq 'LEFT' )
 441                 );
 442         }
 443         $object->set_from_related( $name, $sub_object )
 444             unless (
 445                !$sub_object
 446             && !$updates
 447             && ( exists $info->{attrs}{join_type}
 448                 && $info->{attrs}{join_type} eq 'LEFT' )
 449             );
 450     }
 451     else {
 452         $self->throw_exception(
 453             "recursive_update doesn't now how to handle relationship '$name' with accessor "
 454                 . $info->{attrs}{accessor} );
 455     }
 456 }
 457
 458 sub is_m2m {
 459     my ( $self, $relation ) = @_;
 460     my $rclass = $self->result_class;
 461
 462     # DBIx::Class::IntrospectableM2M
 463     if ( $rclass->can('_m2m_metadata') ) {
 464         return $rclass->_m2m_metadata->{$relation};
 465     }
 466     my $object = $self->new_result( {} );
 467     if (    $object->can($relation)
 468         and !$self->result_source->has_relationship($relation)
 469         and $object->can( 'set_' . $relation ) )
 470     {
 471         return 1;
 472     }
 473     return;
 474 }
 475
 476 sub get_m2m_source {
 477     my ( $self, $relation ) = @_;
 478     my $rclass = $self->result_class;
 479
 480     # DBIx::Class::IntrospectableM2M
 481     if ( $rclass->can('_m2m_metadata') ) {
 482         return $self->result_source->related_source(
 483             $rclass->_m2m_metadata->{$relation}{relation} )
 484             ->related_source(
 485             $rclass->_m2m_metadata->{$relation}{foreign_relation} );
 486     }
 487     my $object = $self->new_result( {} );
 488     my $r = $object->$relation;
 489     return $r->result_source;
 490 }
 491
 492 sub _delete_empty_auto_increment {
 493     my ( $self, $object ) = @_;
 494     for my $col ( keys %{ $object->{_column_data} } ) {
 495         if ($object->result_source->column_info($col)->{is_auto_increment}
 496             and ( !defined $object->{_column_data}{$col}
 497                 or $object->{_column_data}{$col} eq '' )
 498             )
 499         {
 500             delete $object->{_column_data}{$col};
 501         }
 502     }
 503 }
 504
 505 sub _get_pk_for_related {
 506     my ( $self, $relation ) = @_;
 507     my $result_source;
 508     if ( $self->result_source->has_relationship($relation) ) {
 509         $result_source = $self->result_source->related_source($relation);
 510     }
 511
 512     # many to many case
 513     if ( is_m2m( $self, $relation ) ) {
 514         $result_source = get_m2m_source( $self, $relation );
 515     }
 516     return $result_source->primary_columns;
 517 }
 518
 519 # This function determines wheter a relationship should be done before or
 520 # after the row is inserted into the database
 521 # relationships before: belongs_to
 522 # relationships after: has_many, might_have and has_one
 523 # true means before, false after
 524 sub _master_relation_cond {
 525     my ( $self, $name ) = @_;
 526
 527     my $source = $self->result_source;
 528     my $info   = $source->relationship_info($name);
 529
 530     #warn "INFO: " . Dumper($info) . "\n";
 531
 532     # has_many rels are always after
 533     return 0
 534         if $info->{attrs}->{accessor} eq 'multi';
 535
 536     my @foreign_ids = _get_pk_for_related( $self, $name );
 537
 538     #warn "IDS: " . join(', ', @foreign_ids) . "\n";
 539
 540     my $cond = $info->{cond};
 541
 542     sub _inner {
 543         my ( $source, $cond, @foreign_ids ) = @_;
 544
 545         while ( my ( $f_key, $col ) = each %{$cond} ) {
 546
 547             # might_have is not master
 548             $col   =~ s/^self\.//;
 549             $f_key =~ s/^foreign\.//;
 550             if ( $source->column_info($col)->{is_auto_increment} ) {
 551                 return 0;
 552             }
 553             if ( any { $_ eq $f_key } @foreign_ids ) {
 554                 return 1;
 555             }
 556         }
 557         return 0;
 558     }
 559
 560     if ( ref $cond eq 'HASH' ) {
 561         return _inner( $source, $cond, @foreign_ids );
 562     }
 563
 564     # arrayref of hashrefs
 565     elsif ( ref $cond eq 'ARRAY' ) {
 566         for my $new_cond (@$cond) {
 567             return _inner( $source, $new_cond, @foreign_ids );
 568         }
 569     }
 570     else {
 571         $source->throw_exception(
 572             "unhandled relation condition " . ref($cond) );
 573     }
 574     return;
 575 }
 576
 577 1;    # Magic true value required at end of module
 578 __END__
 579
 580 =head1 SYNOPSIS
 581
 582     # The functional interface:
 583
 584     my $schema = MyDB::Schema->connect();
 585     my $new_item = DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update(
 586         resultset => $schema->resultset('User'),
 587         updates => {
 588             id => 1,
 589             owned_dvds => [
 590                 {
 591                     title => "One Flew Over the Cuckoo's Nest"
 592                 }
 593             ]
 594         },
 595         unknown_params_ok => 1,
 596     );
 597
 598
 599     # As ResultSet subclass:
 600
 601     __PACKAGE__->load_namespaces( default_resultset_class => '+DBIx::Class::ResultSet::RecursiveUpdate' );
 602
 603     # in the Schema file (see t/lib/DBSchema.pm).  Or appropriate 'use base' in the ResultSet classes.
 604
 605     my $user = $schema->resultset('User')->recursive_update({
 606         id => 1,
 607         owned_dvds => [
 608             {
 609                 title => "One Flew Over the Cuckoo's Nest"
 610             }
 611         ]
 612     }, {
 613         unknown_params_ok => 1,
 614     });
 615
 616     # You'll get a warning if you pass non-result specific data to
 617     # recursive_update. See L</"Additional data in the updates hashref">
 618     # for more information how to prevent this.
 619
 620 =head1 DESCRIPTION
 621
 622 This is still experimental.
 623
 624 You can feed the ->create method of DBIx::Class with a recursive datastructure
 625 and have the related records created. Unfortunately you cannot do a similar
 626 thing with update_or_create. This module tries to fill that void until
 627 L<DBIx::Class> has an api itself.
 628
 629 The functional interface can be used without modifications of the model,
 630 for example by form processors like L<HTML::FormHandler::Model::DBIC>.
 631
 632 It is a base class for L<DBIx::Class::ResultSet>s providing the method
 633 recursive_update which works just like update_or_create but can recursively
 634 update or create result objects composed of multiple rows. All rows need to be
 635 identified by primary keys so you need to provide them in the update structure
 636 (unless they can be deduced from the parent row. For example a related row of
 637 a belongs_to relationship). If any of the primary key columns are missing,
 638 a new row will be created, with the expectation that the missing columns will
 639 be filled by it (as in the case of auto_increment primary keys).
 640
 641 If the resultset itself stores an assignment for the primary key,
 642 like in the case of:
 643
 644     my $restricted_rs = $user_rs->search( { id => 1 } );
 645
 646 you need to inform recursive_update about the additional predicate with the fixed_fields attribute:
 647
 648     my $user = $restricted_rs->recursive_update( {
 649             owned_dvds => [
 650             {
 651                 title => 'One Flew Over the Cuckoo's Nest'
 652             }
 653             ]
 654         },
 655         {
 656             fixed_fields => [ 'id' ],
 657         }
 658     );
 659
 660 For a many_to_many (pseudo) relation you can supply a list of primary keys
 661 from the other table and it will link the record at hand to those and
 662 only those records identified by them. This is convenient for handling web
 663 forms with check boxes (or a select field with multiple choice) that lets you
 664 update such (pseudo) relations.
 665
 666 For a description how to set up base classes for ResultSets see
 667 L<DBIx::Class::Schema/load_namespaces>.
 668
 669 =head2 Additional data in the updates hashref
 670
 671 If you pass additional data to recursive_update which doesn't match a column
 672 name, column accessor, relationship or many-to-many helper accessor, it will
 673 throw a warning by default. To disable this behaviour you can set the
 674 unknown_params_ok attribute to a true value.
 675
 676 The warning thrown is:
 677 "No such column, relationship, many-to-many helper accessor or generic accessor '$key'"
 678
 679 When used by L<HTML::FormHandler::Model::DBIC> this can happen if you have
 680 additional form fields that aren't relevant to the database but don't have the
 681 noupdate attribute set to a true value.
 682
 683 NOTE: in a future version this behaviour will change and throw an exception
 684 instead of a warning!
 685
 686
 687 =head1 DESIGN CHOICES
 688
 689 Columns and relationships which are excluded from the updates hashref aren't
 690 touched at all.
 691
 692 =head2 Treatment of belongs_to relations
 693
 694 In case the relationship is included but undefined in the updates hashref,
 695 all columns forming the relationship will be set to null.
 696 If not all of them are nullable, DBIx::Class will throw an error.
 697
 698 Updating the relationship:
 699
 700     my $dvd = $dvd_rs->recursive_update( {
 701         id    => 1,
 702         owner => $user->id,
 703     });
 704
 705 Clearing the relationship (only works if cols are nullable!):
 706
 707     my $dvd = $dvd_rs->recursive_update( {
 708         id    => 1,
 709         owner => undef,
 710     });
 711
 712 =head2 Treatment of might_have relationships
 713
 714 In case the relationship is included but undefined in the updates hashref,
 715 all columns forming the relationship will be set to null.
 716
 717 Updating the relationship:
 718
 719     my $user = $user_rs->recursive_update( {
 720         id => 1,
 721         address => {
 722             street => "101 Main Street",
 723             city   => "Podunk",
 724             state  => "New York",
 725         }
 726     });
 727
 728 Clearing the relationship:
 729
 730     my $user = $user_rs->recursive_update( {
 731         id => 1,
 732         address => undef,
 733     });
 734
 735 =head2 Treatment of has_many relations
 736
 737 If a relationship key is included in the data structure with a value of undef
 738 or an empty array, all existing related rows will be deleted, or their foreign
 739 key columns will be set to null.
 740
 741 The exact behaviour depends on the nullability of the foreign key columns and
 742 the value of the "if_not_submitted" parameter. The parameter defaults to
 743 undefined which neither nullifies nor deletes.
 744
 745 When the array contains elements they are updated if they exist, created when
 746 not and deleted if not included.
 747
 748 =head3 All foreign table columns are nullable
 749
 750 In this case recursive_update defaults to nullifying the foreign columns.
 751
 752 =head3 Not all foreign table columns are nullable
 753
 754 In this case recursive_update deletes the foreign rows.
 755
 756 Updating the relationship:
 757
 758     Passing ids:
 759
 760     my $user = $user_rs->recursive_update( {
 761         id         => 1,
 762         owned_dvds => [1, 2],
 763     });
 764
 765     Passing hashrefs:
 766
 767     my $user = $user_rs->recursive_update( {
 768         id         => 1,
 769         owned_dvds => [
 770             {
 771                 name => 'temp name 1',
 772             },
 773             {
 774                 name => 'temp name 2',
 775             },
 776         ],
 777     });
 778
 779     Passing objects:
 780
 781     my $user = $user_rs->recursive_update( {
 782         id         => 1,
 783         owned_dvds => [ $dvd1, $dvd2 ],
 784     });
 785
 786     You can even mix them:
 787
 788     my $user = $user_rs->recursive_update( {
 789         id         => 1,
 790         owned_dvds => [ 1, { id => 2 } ],
 791     });
 792
 793 Clearing the relationship:
 794
 795     my $user = $user_rs->recursive_update( {
 796         id         => 1,
 797         owned_dvds => undef,
 798     });
 799
 800     This is the same as passing an empty array:
 801
 802     my $user = $user_rs->recursive_update( {
 803         id         => 1,
 804         owned_dvds => [],
 805     });
 806
 807 =head2 Treatment of many-to-many pseudo relations
 808
 809 If a many-to-many accessor key is included in the data structure with a value
 810 of undef or an empty array, all existing related rows are unlinked.
 811
 812 When the array contains elements they are updated if they exist, created when
 813 not and deleted if not included.
 814
 815 See L</is_m2m> for many-to-many pseudo relationship detection.
 816
 817 Updating the relationship:
 818
 819     Passing ids:
 820
 821     my $dvd = $dvd_rs->recursive_update( {
 822         id   => 1,
 823         tags => [1, 2],
 824     });
 825
 826     Passing hashrefs:
 827
 828     my $dvd = $dvd_rs->recursive_update( {
 829         id   => 1,
 830         tags => [
 831             {
 832                 id   => 1,
 833                 file => 'file0'
 834             },
 835             {
 836                 id   => 2,
 837                 file => 'file1',
 838             },
 839         ],
 840     });
 841
 842     Passing objects:
 843
 844     my $dvd = $dvd_rs->recursive_update( {
 845         id   => 1,
 846         tags => [ $tag1, $tag2 ],
 847     });
 848
 849     You can even mix them:
 850
 851     my $dvd = $dvd_rs->recursive_update( {
 852         id   => 1,
 853         tags => [ 2, { id => 3 } ],
 854     });
 855
 856 Clearing the relationship:
 857
 858     my $dvd = $dvd_rs->recursive_update( {
 859         id   => 1,
 860         tags => undef,
 861     });
 862
 863     This is the same as passing an empty array:
 864
 865     my $dvd = $dvd_rs->recursive_update( {
 866         id   => 1,
 867         tags => [],
 868     });
 869
 870
 871 =head1 INTERFACE
 872
 873 =head1 METHODS
 874
 875 =head2 recursive_update
 876
 877 The method that does the work here.
 878
 879 =head2 is_m2m
 880
 881 =over 4
 882
 883 =item Arguments: $name
 884
 885 =item Return Value: true, if $name is a many to many pseudo-relationship
 886
 887 =back
 888
 889 The function gets the information about m2m relations from
 890 L<DBIx::Class::IntrospectableM2M>. If it isn't loaded in the ResultSource
 891 class, the code relies on the fact:
 892
 893     if($object->can($name) and
 894              !$object->result_source->has_relationship($name) and
 895              $object->can( 'set_' . $name )
 896          )
 897
 898 to identify a many to many pseudo relationship. In a similar ugly way the
 899 ResultSource of that many to many pseudo relationship is detected.
 900
 901 So if you need many to many pseudo relationship support, it's strongly
 902 recommended to load L<DBIx::Class::IntrospectableM2M> in your ResultSource
 903 class!
 904
 905 =head2 get_m2m_source
 906
 907 =over 4
 908
 909 =item Arguments: $name
 910
 911 =item Return Value: $result_source
 912
 913 =back
 914
 915 =head1 CONFIGURATION AND ENVIRONMENT
 916
 917 DBIx::Class::RecursiveUpdate requires no configuration files or environment variables.
 918
 919 =head1 DEPENDENCIES
 920
 921     DBIx::Class
 922
 923 optional but recommended:
 924     DBIx::Class::IntrospectableM2M
 925
 926 =head1 INCOMPATIBILITIES
 927
 928 None reported.
 929
 930
 931 =head1 BUGS AND LIMITATIONS
 932
 933 The list of reported bugs can be viewed at L<http://rt.cpan.org/Public/Dist/Display.html?Name=DBIx-Class-ResultSet-RecursiveUpdate>.
 934
 935 Please report any bugs or feature requests to
 936 C<bug-dbix-class-recursiveput@rt.cpan.org>, or through the web interface at
 937 L<http://rt.cpan.org>.