documentation fixes and improvements
[chaz/p5-DBIx-Class-ResultSet-RecursiveUpdate] / 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 # warn 'entering: ' . $self->result_source->from();
51 carp 'fixed fields needs to be an array ref'
52 if defined $fixed_fields && ref $fixed_fields ne 'ARRAY';
53
54 if ( blessed($updates) && $updates->isa('DBIx::Class::Row') ) {
55 return $updates;
56 }
57 if ( $updates->{id} ) {
58 $object = $self->find( $updates->{id}, { key => 'primary' } );
59 }
60
61 my %fixed_fields = map { $_ => 1 } @$fixed_fields
62 if $fixed_fields;
63 my @missing =
64 grep { !exists $updates->{$_} && !exists $fixed_fields{$_} }
65 $self->result_source->primary_columns;
66 if ( !$object && !scalar @missing ) {
67
68 # warn 'finding by: ' . Dumper( $updates ); use Data::Dumper;
69 $object = $self->find( $updates, { key => 'primary' } );
70 }
71 $updates = { %$updates, %$resolved };
72 @missing =
73 grep { !exists $resolved->{$_} } @missing;
74 if ( !$object && !scalar @missing ) {
75
76 # warn 'finding by +resolved: ' . Dumper( $updates ); use Data::Dumper;
77 $object = $self->find( $updates, { key => 'primary' } );
78 }
79 $object ||= $self->new( {} );
80
81 # warn Dumper( $updates ); use Data::Dumper;
82 # direct column accessors
83 my %columns;
84
85 # relations that that should be done before the row is inserted into the
86 # database like belongs_to
87 my %pre_updates;
88
89 # relations that that should be done after the row is inserted into the
90 # database like has_many, might_have and has_one
91 my %post_updates;
92 my %other_methods;
93 my %columns_by_accessor = _get_columns_by_accessor($self);
94
95 # warn 'resolved: ' . Dumper( $resolved );
96 # warn 'updates: ' . Dumper( $updates ); use Data::Dumper;
97 # warn 'columns: ' . Dumper( \%columns_by_accessor );
98 for my $name ( keys %$updates ) {
99 my $source = $self->result_source;
100
101 # columns
102 if ( exists $columns_by_accessor{$name}
103 && !( $source->has_relationship($name)
104 && ref( $updates->{$name} ) ) )
105 {
106
107 #warn "$name is a column\n";
108 $columns{$name} = $updates->{$name};
109 next;
110 }
111
112 # relationships
113 if ( $source->has_relationship($name) ) {
114 if ( _master_relation_cond( $self, $name ) ) {
115
116 #warn "$name is a pre-update rel\n";
117 $pre_updates{$name} = $updates->{$name};
118 next;
119 }
120 else {
121
122 #warn "$name is a post-update rel\n";
123 $post_updates{$name} = $updates->{$name};
124 next;
125 }
126 }
127
128 # many-to-many helper accessors
129 if ( is_m2m( $self, $name ) ) {
130
131 #warn "$name is a many-to-many helper accessor\n";
132 $other_methods{$name} = $updates->{$name};
133 next;
134 }
135
136 # accessors
137 if ( $object->can($name) && not $source->has_relationship($name) ) {
138
139 #warn "$name is an accessor";
140 $other_methods{$name} = $updates->{$name};
141 next;
142 }
143
144 # unknown
145
146 # don't throw a warning instead of an exception to give users
147 # time to adapt to the new API
148 carp(
149 "No such column, relationship, many-to-many helper accessor or generic accessor '$name'"
150 ) unless $unknown_params_ok;
151
152 #$self->throw_exception(
153 # "No such column, relationship, many-to-many helper accessor or generic accessor '$name'"
154 #);
155 }
156
157 # warn 'other: ' . Dumper( \%other_methods ); use Data::Dumper;
158
159 # first update columns and other accessors
160 # so that later related records can be found
161 for my $name ( keys %columns ) {
162
163 #warn "update col $name\n";
164 $object->$name( $columns{$name} );
165 }
166 for my $name ( keys %other_methods ) {
167
168 #warn "update other $name\n";
169 $object->$name( $updates->{$name} );
170 }
171 for my $name ( keys %pre_updates ) {
172
173 #warn "pre_update $name\n";
174 _update_relation( $self, $name, $pre_updates{$name}, $object,
175 $if_not_submitted );
176 }
177
178 # $self->_delete_empty_auto_increment($object);
179 # don't allow insert to recurse to related objects
180 # do the recursion ourselves
181 # $object->{_rel_in_storage} = 1;
182 #warn "CHANGED: " . $object->is_changed . "\n":
183 #warn "IN STOR: " . $object->in_storage . "\n";
184 $object->update_or_insert if $object->is_changed;
185 $object->discard_changes;
186
187 # updating many_to_many
188 for my $name ( keys %$updates ) {
189 next if exists $columns{$name};
190 my $value = $updates->{$name};
191
192 if ( is_m2m( $self, $name ) ) {
193
194 #warn "update m2m $name\n";
195 my ($pk) = _get_pk_for_related( $self, $name );
196 my @rows;
197 my $result_source = $object->$name->result_source;
198 my @updates;
199 if ( !defined $value ) {
200 next;
201 }
202 elsif ( ref $value ) {
203 @updates = @{$value};
204 }
205 else {
206 @updates = ($value);
207 }
208 for my $elem (@updates) {
209 if ( ref $elem ) {
210 push @rows,
211 recursive_update(
212 resultset => $result_source->resultset,
213 updates => $elem
214 );
215 }
216 else {
217 push @rows,
218 $result_source->resultset->find( { $pk => $elem } );
219 }
220 }
221 my $set_meth = 'set_' . $name;
222 $object->$set_meth( \@rows );
223 }
224 }
225 for my $name ( keys %post_updates ) {
226
227 #warn "post_update $name\n";
228 _update_relation( $self, $name, $post_updates{$name}, $object,
229 $if_not_submitted );
230 }
231 return $object;
232 }
233
234 # returns DBIx::Class::ResultSource::column_info as a hash indexed by column accessor || name
235 sub _get_columns_by_accessor {
236 my $self = shift;
237 my $source = $self->result_source;
238 my %columns;
239 for my $name ( $source->columns ) {
240 my $info = $source->column_info($name);
241 $info->{name} = $name;
242 $columns{ $info->{accessor} || $name } = $info;
243 }
244 return %columns;
245 }
246
247 # Arguments: $rs, $name, $updates, $row, $if_not_submitted
248 sub _update_relation {
249 my ( $self, $name, $updates, $object, $if_not_submitted ) = @_;
250
251 # this should never happen because we're checking the paramters passed to
252 # recursive_update, but just to be sure...
253 $object->throw_exception("No such relationship '$name'")
254 unless $object->has_relationship($name);
255
256 #warn "_update_relation $name: OBJ: " . ref($object) . "\n";
257
258 my $info = $object->result_source->relationship_info($name);
259
260 # get a related resultset without a condition
261 my $related_resultset =
262 $self->related_resultset($name)->result_source->resultset;
263 my $resolved;
264 if ( $self->result_source->can('_resolve_condition') ) {
265 $resolved =
266 $self->result_source->_resolve_condition( $info->{cond}, $name,
267 $object );
268 }
269 else {
270 $self->throw_exception(
271 "result_source must support _resolve_condition");
272 }
273
274 # warn "$name resolved: " . Dumper( $resolved ); use Data::Dumper;
275 $resolved = {}
276 if defined $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
277 && $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
278 == $resolved;
279
280 my @rel_cols = keys %{ $info->{cond} };
281 map {s/^foreign\.//} @rel_cols;
282
283 #warn "REL_COLS: " . Dumper(@rel_cols); use Data::Dumper;
284 #my $rel_col_cnt = scalar @rel_cols;
285
286 # find out if all related columns are nullable
287 my $all_fks_nullable = 1;
288 for my $rel_col (@rel_cols) {
289 $all_fks_nullable = 0
290 unless $related_resultset->result_source->column_info($rel_col)
291 ->{is_nullable};
292 }
293
294 $if_not_submitted = $all_fks_nullable ? 'nullify' : 'delete'
295 unless defined $if_not_submitted;
296
297 #warn "\tNULLABLE: $all_fks_nullable ACTION: $if_not_submitted\n";
298
299 #warn "RELINFO for $name: " . Dumper($info); use Data::Dumper;
300
301 # the only valid datatype for a has_many rels is an arrayref
302 if ( $info->{attrs}{accessor} eq 'multi' ) {
303
304 # handle undef like empty arrayref
305 $updates = []
306 unless defined $updates;
307 $self->throw_exception(
308 "data for has_many relationship '$name' must be an arrayref")
309 unless ref $updates eq 'ARRAY';
310
311 my @updated_objs;
312
313 #warn "\tupdating has_many rel '$name' ($rel_col_cnt columns cols)\n";
314 for my $sub_updates ( @{$updates} ) {
315 my $sub_object = recursive_update(
316 resultset => $related_resultset,
317 updates => $sub_updates,
318 resolved => $resolved
319 );
320
321 push @updated_objs, $sub_object;
322 }
323
324 #warn "\tcreated and updated related rows\n";
325
326 my @related_pks = $related_resultset->result_source->primary_columns;
327
328 my $rs_rel_delist = $object->$name;
329
330 # foreign table has a single pk column
331 if ( scalar @related_pks == 1 ) {
332 $rs_rel_delist = $rs_rel_delist->search_rs(
333 { $related_pks[0] =>
334 { -not_in => [ map ( $_->id, @updated_objs ) ] }
335 }
336 );
337 }
338
339 # foreign table has multiple pk columns
340 else {
341 my @cond;
342 for my $obj (@updated_objs) {
343 my %cond_for_obj;
344 for my $col (@related_pks) {
345 $cond_for_obj{$col} = $obj->get_column($col);
346 }
347 push @cond, \%cond_for_obj;
348 }
349
350 # only limit resultset if there are related rows left
351 if ( scalar @cond ) {
352 $rs_rel_delist =
353 $rs_rel_delist->search_rs( { -not => [@cond] } );
354 }
355 }
356
357 #warn "\tCOND: " . Dumper(\%cond);
358 #my $rel_delist_cnt = $rs_rel_delist->count;
359 if ( $if_not_submitted eq 'delete' ) {
360
361 #warn "\tdeleting related rows: $rel_delist_cnt\n";
362 $rs_rel_delist->delete;
363 }
364 elsif ( $if_not_submitted eq 'set_to_null' ) {
365
366 #warn "\tnullifying related rows: $rel_delist_cnt\n";
367 my %update = map { $_ => undef } @rel_cols;
368 $rs_rel_delist->update( \%update );
369 }
370 }
371 elsif ($info->{attrs}{accessor} eq 'single'
372 || $info->{attrs}{accessor} eq 'filter' )
373 {
374
375 #warn "\tupdating rel '$name': $if_not_submitted\n";
376 my $sub_object;
377 if ( ref $updates ) {
378
379 # for might_have relationship
380 if ( $info->{attrs}{accessor} eq 'single'
381 && defined $object->$name )
382 {
383 $sub_object = recursive_update(
384 resultset => $related_resultset,
385 updates => $updates,
386 object => $object->$name
387 );
388 }
389 else {
390 $sub_object = recursive_update(
391 resultset => $related_resultset,
392 updates => $updates,
393 resolved => $resolved
394 );
395 }
396 }
397 else {
398 $sub_object = $related_resultset->find($updates)
399 unless (
400 !$updates
401 && ( exists $info->{attrs}{join_type}
402 && $info->{attrs}{join_type} eq 'LEFT' )
403 );
404 }
405 $object->set_from_related( $name, $sub_object )
406 unless (
407 !$sub_object
408 && !$updates
409 && ( exists $info->{attrs}{join_type}
410 && $info->{attrs}{join_type} eq 'LEFT' )
411 );
412 }
413 else {
414 $self->throw_exception(
415 "recursive_update doesn't now how to handle relationship '$name' with accessor "
416 . $info->{attrs}{accessor} );
417 }
418 }
419
420 sub is_m2m {
421 my ( $self, $relation ) = @_;
422 my $rclass = $self->result_class;
423
424 # DBIx::Class::IntrospectableM2M
425 if ( $rclass->can('_m2m_metadata') ) {
426 return $rclass->_m2m_metadata->{$relation};
427 }
428 my $object = $self->new( {} );
429 if ( $object->can($relation)
430 and !$self->result_source->has_relationship($relation)
431 and $object->can( 'set_' . $relation ) )
432 {
433 return 1;
434 }
435 return;
436 }
437
438 sub get_m2m_source {
439 my ( $self, $relation ) = @_;
440 my $rclass = $self->result_class;
441
442 # DBIx::Class::IntrospectableM2M
443 if ( $rclass->can('_m2m_metadata') ) {
444 return $self->result_source->related_source(
445 $rclass->_m2m_metadata->{$relation}{relation} )
446 ->related_source(
447 $rclass->_m2m_metadata->{$relation}{foreign_relation} );
448 }
449 my $object = $self->new( {} );
450 my $r = $object->$relation;
451 return $r->result_source;
452 }
453
454 sub _delete_empty_auto_increment {
455 my ( $self, $object ) = @_;
456 for my $col ( keys %{ $object->{_column_data} } ) {
457 if ($object->result_source->column_info($col)->{is_auto_increment}
458 and ( !defined $object->{_column_data}{$col}
459 or $object->{_column_data}{$col} eq '' )
460 )
461 {
462 delete $object->{_column_data}{$col};
463 }
464 }
465 }
466
467 sub _get_pk_for_related {
468 my ( $self, $relation ) = @_;
469 my $result_source;
470 if ( $self->result_source->has_relationship($relation) ) {
471 $result_source = $self->result_source->related_source($relation);
472 }
473
474 # many to many case
475 if ( is_m2m( $self, $relation ) ) {
476 $result_source = get_m2m_source( $self, $relation );
477 }
478 return $result_source->primary_columns;
479 }
480
481 # This function determines wheter a relationship should be done before or
482 # after the row is inserted into the database
483 # relationships before: belongs_to
484 # relationships after: has_many, might_have and has_one
485 # true means before, false after
486 sub _master_relation_cond {
487 my ( $self, $name ) = @_;
488
489 my $source = $self->result_source;
490 my $info = $source->relationship_info($name);
491
492 #warn "INFO: " . Dumper($info) . "\n";
493
494 # has_many rels are always after
495 return 0
496 if $info->{attrs}->{accessor} eq 'multi';
497
498 my @foreign_ids = _get_pk_for_related( $self, $name );
499
500 #warn "IDS: " . join(', ', @foreign_ids) . "\n";
501
502 my $cond = $info->{cond};
503
504 sub _inner {
505 my ( $source, $cond, @foreign_ids ) = @_;
506
507 while ( my ( $f_key, $col ) = each %{$cond} ) {
508
509 # might_have is not master
510 $col =~ s/^self\.//;
511 $f_key =~ s/^foreign\.//;
512 if ( $source->column_info($col)->{is_auto_increment} ) {
513 return 0;
514 }
515 if ( any { $_ eq $f_key } @foreign_ids ) {
516 return 1;
517 }
518 }
519 return 0;
520 }
521
522 if ( ref $cond eq 'HASH' ) {
523 return _inner( $source, $cond, @foreign_ids );
524 }
525
526 # arrayref of hashrefs
527 elsif ( ref $cond eq 'ARRAY' ) {
528 for my $new_cond (@$cond) {
529 return _inner( $source, $new_cond, @foreign_ids );
530 }
531 }
532 else {
533 $source->throw_exception(
534 "unhandled relation condition " . ref($cond) );
535 }
536 return;
537 }
538
539 1; # Magic true value required at end of module
540 __END__
541
542 =head1 SYNOPSIS
543
544 # The functional interface:
545
546 my $schema = MyDB::Schema->connect();
547 my $new_item = DBIx::Class::ResultSet::RecursiveUpdate::Functions::recursive_update(
548 resultset => $schema->resultset('User'),
549 updates => {
550 id => 1,
551 owned_dvds => [
552 {
553 title => "One Flew Over the Cuckoo's Nest"
554 }
555 ]
556 },
557 unknown_params_ok => 1,
558 );
559
560
561 # As ResultSet subclass:
562
563 __PACKAGE__->load_namespaces( default_resultset_class => '+DBIx::Class::ResultSet::RecursiveUpdate' );
564
565 # in the Schema file (see t/lib/DBSchema.pm). Or appropriate 'use base' in the ResultSet classes.
566
567 my $user = $schema->resultset('User')->recursive_update({
568 id => 1,
569 owned_dvds => [
570 {
571 title => "One Flew Over the Cuckoo's Nest"
572 }
573 ]
574 }, {
575 unknown_params_ok => 1,
576 });
577
578 # You'll get a warning if you pass non-result specific data to
579 # recursive_update. See L</"Additional data in the updates hashref">
580 # for more information how to prevent this.
581
582 =head1 DESCRIPTION
583
584 This is still experimental.
585
586 You can feed the ->create method of DBIx::Class with a recursive datastructure
587 and have the related records created. Unfortunately you cannot do a similar
588 thing with update_or_create. This module tries to fill that void until
589 L<DBIx::Class> has an api itself.
590
591 The functional interface can be used without modifications of the model,
592 for example by form processors like L<HTML::FormHandler::Model::DBIC>.
593
594 It is a base class for L<DBIx::Class::ResultSet>s providing the method
595 recursive_update which works just like update_or_create but can recursively
596 update or create result objects composed of multiple rows. All rows need to be
597 identified by primary keys so you need to provide them in the update structure
598 (unless they can be deduced from the parent row. For example a related row of
599 a belongs_to relationship). If any of the primary key columns are missing,
600 a new row will be created, with the expectation that the missing columns will
601 be filled by it (as in the case of auto_increment primary keys).
602
603 If the resultset itself stores an assignment for the primary key,
604 like in the case of:
605
606 my $restricted_rs = $user_rs->search( { id => 1 } );
607
608 you need to inform recursive_update about the additional predicate with the fixed_fields attribute:
609
610 my $user = $restricted_rs->recursive_update( {
611 owned_dvds => [
612 {
613 title => 'One Flew Over the Cuckoo's Nest'
614 }
615 ]
616 },
617 {
618 fixed_fields => [ 'id' ],
619 }
620 );
621
622 For a many_to_many (pseudo) relation you can supply a list of primary keys
623 from the other table and it will link the record at hand to those and
624 only those records identified by them. This is convenient for handling web
625 forms with check boxes (or a select field with multiple choice) that lets you
626 update such (pseudo) relations.
627
628 For a description how to set up base classes for ResultSets see
629 L<DBIx::Class::Schema/load_namespaces>.
630
631 =head2 Additional data in the updates hashref
632
633 If you pass additional data to recursive_update which doesn't match a column
634 name, column accessor, relationship or many-to-many helper accessor, it will
635 throw a warning by default. To disable this behaviour you can set the
636 unknown_params_ok attribute to a true value.
637
638 The warning thrown is:
639 "No such column, relationship, many-to-many helper accessor or generic accessor '$key'"
640
641 When used by L<HTML::FormHandler::Model::DBIC> this can happen if you have
642 additional form fields that aren't relevant to the database but don't have the
643 noupdate attribute set to a true value.
644
645 NOTE: in a future version this behaviour will change and throw an exception
646 instead of a warning!
647
648
649 =head1 DESIGN CHOICES
650
651 Columns and relationships which are excluded from the updates hashref aren't
652 touched at all.
653
654 =head2 Treatment of belongs_to relations
655
656 In case the relationship is included but undefined in the updates hashref,
657 all columns forming the relationship will be set to null.
658 If not all of them are nullable, DBIx::Class will throw an error.
659
660 Updating the relationship:
661
662 my $dvd = $dvd_rs->recursive_update( {
663 id => 1,
664 owner => $user->id,
665 });
666
667 Clearing the relationship (only works if cols are nullable!):
668
669 my $dvd = $dvd_rs->recursive_update( {
670 id => 1,
671 owner => undef,
672 });
673
674 =head2 Treatment of might_have relationships
675
676 In case the relationship is included but undefined in the updates hashref,
677 all columns forming the relationship will be set to null.
678
679 Updating the relationship:
680
681 my $user = $user_rs->recursive_update( {
682 id => 1,
683 address => {
684 street => "101 Main Street",
685 city => "Podunk",
686 state => "New York",
687 }
688 });
689
690 Clearing the relationship:
691
692 my $user = $user_rs->recursive_update( {
693 id => 1,
694 address => undef,
695 });
696
697 =head2 Treatment of has_many relations
698
699 If a relationship key is included in the data structure with a value of undef
700 or an empty array, all existing related rows will be deleted, or their foreign
701 key columns will be set to null.
702
703 The exact behaviour depends on the nullability of the foreign key columns and
704 the value of the "if_not_submitted" parameter. The parameter defaults to
705 undefined which neither nullifies nor deletes.
706
707 When the array contains elements they are updated if they exist, created when
708 not and deleted if not included.
709
710 =head3 All foreign table columns are nullable
711
712 In this case recursive_update defaults to nullifying the foreign columns.
713
714 =head3 Not all foreign table columns are nullable
715
716 In this case recursive_update deletes the foreign rows.
717
718 Updating the relationship:
719
720 Passing ids:
721
722 my $user = $user_rs->recursive_update( {
723 id => 1,
724 owned_dvds => [1, 2],
725 });
726
727 Passing hashrefs:
728
729 my $user = $user_rs->recursive_update( {
730 id => 1,
731 owned_dvds => [
732 {
733 name => 'temp name 1',
734 },
735 {
736 name => 'temp name 2',
737 },
738 ],
739 });
740
741 Passing objects:
742
743 my $user = $user_rs->recursive_update( {
744 id => 1,
745 owned_dvds => [ $dvd1, $dvd2 ],
746 });
747
748 You can even mix them:
749
750 my $user = $user_rs->recursive_update( {
751 id => 1,
752 owned_dvds => [ 1, { id => 2 } ],
753 });
754
755 Clearing the relationship:
756
757 my $user = $user_rs->recursive_update( {
758 id => 1,
759 owned_dvds => undef,
760 });
761
762 This is the same as passing an empty array:
763
764 my $user = $user_rs->recursive_update( {
765 id => 1,
766 owned_dvds => [],
767 });
768
769 =head2 Treatment of many-to-many pseudo relations
770
771 If a many-to-many accessor key is included in the data structure with a value
772 of undef or an empty array, all existing related rows are unlinked.
773
774 When the array contains elements they are updated if they exist, created when
775 not and deleted if not included.
776
777 See L</is_m2m> for many-to-many pseudo relationship detection.
778
779 Updating the relationship:
780
781 Passing ids:
782
783 my $dvd = $dvd_rs->recursive_update( {
784 id => 1,
785 tags => [1, 2],
786 });
787
788 Passing hashrefs:
789
790 my $dvd = $dvd_rs->recursive_update( {
791 id => 1,
792 tags => [
793 {
794 id => 1,
795 file => 'file0'
796 },
797 {
798 id => 2,
799 file => 'file1',
800 },
801 ],
802 });
803
804 Passing objects:
805
806 my $dvd = $dvd_rs->recursive_update( {
807 id => 1,
808 tags => [ $tag1, $tag2 ],
809 });
810
811 You can even mix them:
812
813 my $dvd = $dvd_rs->recursive_update( {
814 id => 1,
815 tags => [ 2, { id => 3 } ],
816 });
817
818 Clearing the relationship:
819
820 my $dvd = $dvd_rs->recursive_update( {
821 id => 1,
822 tags => undef,
823 });
824
825 This is the same as passing an empty array:
826
827 my $dvd = $dvd_rs->recursive_update( {
828 id => 1,
829 tags => [],
830 });
831
832
833 =head1 INTERFACE
834
835 =head1 METHODS
836
837 =head2 recursive_update
838
839 The method that does the work here.
840
841 =head2 is_m2m
842
843 =over 4
844
845 =item Arguments: $name
846
847 =item Return Value: true, if $name is a many to many pseudo-relationship
848
849 =back
850
851 The function gets the information about m2m relations from
852 L<DBIx::Class::IntrospectableM2M>. If it isn't loaded in the ResultSource
853 class, the code relies on the fact:
854
855 if($object->can($name) and
856 !$object->result_source->has_relationship($name) and
857 $object->can( 'set_' . $name )
858 )
859
860 to identify a many to many pseudo relationship. In a similar ugly way the
861 ResultSource of that many to many pseudo relationship is detected.
862
863 So if you need many to many pseudo relationship support, it's strongly
864 recommended to load L<DBIx::Class::IntrospectableM2M> in your ResultSource
865 class!
866
867 =head2 get_m2m_source
868
869 =over 4
870
871 =item Arguments: $name
872
873 =item Return Value: $result_source
874
875 =back
876
877 =head1 CONFIGURATION AND ENVIRONMENT
878
879 DBIx::Class::RecursiveUpdate requires no configuration files or environment variables.
880
881 =head1 DEPENDENCIES
882
883 DBIx::Class
884
885 optional but recommended:
886 DBIx::Class::IntrospectableM2M
887
888 =head1 INCOMPATIBILITIES
889
890 None reported.
891
892
893 =head1 BUGS AND LIMITATIONS
894
895 The list of reported bugs can be viewed at L<http://rt.cpan.org/Public/Dist/Display.html?Name=DBIx-Class-ResultSet-RecursiveUpdate>.
896
897 Please report any bugs or feature requests to
898 C<bug-dbix-class-recursiveput@rt.cpan.org>, or through the web interface at
899 L<http://rt.cpan.org>.
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