1 package DBIx::Class::Relationship::Base;
6 use base qw/DBIx::Class/;
8 use Scalar::Util qw/weaken blessed/;
10 use DBIx::Class::_Util 'UNRESOLVABLE_CONDITION';
15 DBIx::Class::Relationship::Base - Inter-table relationships
19 __PACKAGE__->add_relationship(
20 spiders => 'My::DB::Result::Creatures',
24 "$args->{foreign_alias}.id" => { -ident => "$args->{self_alias}.id" },
25 "$args->{foreign_alias}.type" => 'arachnid'
32 This class provides methods to describe the relationships between the
33 tables in your database model. These are the "bare bones" relationships
34 methods, for predefined ones, look in L<DBIx::Class::Relationship>.
38 =head2 add_relationship
42 =item Arguments: $rel_name, $foreign_class, $condition, $attrs
46 __PACKAGE__->add_relationship('rel_name',
50 Create a custom relationship between one result source and another
51 source, indicated by its class name.
55 The condition argument describes the C<ON> clause of the C<JOIN>
56 expression used to connect the two sources when creating SQL queries.
58 =head4 Simple equality
60 To create simple equality joins, supply a hashref containing the remote
61 table column name as the key(s) prefixed by C<'foreign.'>, and the
62 corresponding local table column name as the value(s) prefixed by C<'self.'>.
63 Both C<foreign> and C<self> are pseudo aliases and must be entered
64 literally. They will be replaced with the actual correct table alias
65 when the SQL is produced.
69 My::Schema::Author->has_many(
70 books => 'My::Schema::Book',
71 { 'foreign.author_id' => 'self.id' }
76 $author_rs->search_related('books')->next
78 will result in the following C<JOIN> clause:
80 ... FROM author me LEFT JOIN book books ON books.author_id = me.id ...
82 This describes a relationship between the C<Author> table and the
83 C<Book> table where the C<Book> table has a column C<author_id>
84 containing the ID value of the C<Author>.
88 My::Schema::Book->has_many(
89 editions => 'My::Schema::Edition',
91 'foreign.publisher_id' => 'self.publisher_id',
92 'foreign.type_id' => 'self.type_id',
98 $book_rs->search_related('editions')->next
100 will result in the C<JOIN> clause:
103 LEFT JOIN edition editions ON
104 editions.publisher_id = me.publisher_id
105 AND editions.type_id = me.type_id ...
107 This describes the relationship from C<Book> to C<Edition>, where the
108 C<Edition> table refers to a publisher and a type (e.g. "paperback"):
110 =head4 Multiple groups of simple equality conditions
112 As is the default in L<SQL::Abstract>, the key-value pairs will be
113 C<AND>ed in the resulting C<JOIN> clause. An C<OR> can be achieved with
114 an arrayref. For example a condition like:
116 My::Schema::Item->has_many(
117 related_item_links => My::Schema::Item::Links,
119 { 'foreign.left_itemid' => 'self.id' },
120 { 'foreign.right_itemid' => 'self.id' },
124 will translate to the following C<JOIN> clause:
126 ... FROM item me JOIN item_relations related_item_links ON
127 related_item_links.left_itemid = me.id
128 OR related_item_links.right_itemid = me.id ...
130 This describes the relationship from C<Item> to C<Item::Links>, where
131 C<Item::Links> is a many-to-many linking table, linking items back to
132 themselves in a peer fashion (without a "parent-child" designation)
134 =head4 Custom join conditions
136 NOTE: The custom join condition specification mechanism is capable of
137 generating JOIN clauses of virtually unlimited complexity. This may limit
138 your ability to traverse some of the more involved relationship chains the
139 way you expect, *and* may bring your RDBMS to its knees. Exercise care
140 when declaring relationships as described here.
142 To specify joins which describe more than a simple equality of column
143 values, the custom join condition coderef syntax can be used. For
146 My::Schema::Artist->has_many(
147 cds_80s => 'My::Schema::CD',
152 "$args->{foreign_alias}.artist" => { -ident => "$args->{self_alias}.artistid" },
153 "$args->{foreign_alias}.year" => { '>', "1979", '<', "1990" },
160 $artist_rs->search_related('cds_80s')->next;
162 will result in the C<JOIN> clause:
164 ... FROM artist me LEFT JOIN cd cds_80s ON
165 cds_80s.artist = me.artistid
169 with the bind values:
173 C<< $args->{foreign_alias} >> and C<< $args->{self_alias} >> are supplied the
174 same values that would be otherwise substituted for C<foreign> and C<self>
175 in the simple hashref syntax case.
177 The coderef is expected to return a valid L<SQL::Abstract> query-structure, just
178 like what one would supply as the first argument to
179 L<DBIx::Class::ResultSet/search>. The return value will be passed directly to
180 L<SQL::Abstract> and the resulting SQL will be used verbatim as the C<ON>
181 clause of the C<JOIN> statement associated with this relationship.
183 While every coderef-based condition must return a valid C<ON> clause, it may
184 elect to additionally return a simplified B<optional> join-free condition
185 hashref when invoked as C<< $result->$relationship >>, as opposed to
186 C<< $rs->related_resultset('relationship') >>. In this case C<$result> is
187 passed to the coderef as C<< $args->{self_result_object} >>. Alternatively
188 the user-space could be calling C<< $result->set_from_related( $rel =>
189 $foreign_related_object ) >>, in which case C<$foreign_related_object> will
190 be passed to the coderef as C<< $args->{foreign_result_object >>. In other
191 words if you define your condition coderef as:
198 "$args->{foreign_alias}.artist" => { -ident => "$args->{self_alias}.artistid" },
199 "$args->{foreign_alias}.year" => { '>', "1979", '<', "1990" },
201 ! $args->{self_result_object} ? () : {
202 "$args->{foreign_alias}.artist" => $args->{self_result_object}->artistid,
203 "$args->{foreign_alias}.year" => { '>', "1979", '<', "1990" },
205 ! $args->{foreign_result_object} ? () : {
206 "$args->{self_alias}.artistid" => $args->{foreign_result_object}->artist,
213 my $artist = $schema->resultset("Artist")->find({ id => 4 });
214 $artist->cds_80s->all;
216 Can skip a C<JOIN> altogether and instead produce:
218 SELECT cds_80s.cdid, cds_80s.artist, cds_80s.title, cds_80s.year, cds_80s.genreid, cds_80s.single_track
220 WHERE cds_80s.artist = ?
224 With the bind values:
230 my $cd = $schema->resultset("CD")->search({ artist => 1 }, { rows => 1 })->single;
231 my $artist = $schema->resultset("Artist")->new({});
232 $artist->set_from_related('cds_80s');
234 Will properly set the C<< $artist->artistid >> field of this new object to C<1>
236 Note that in order to be able to use
237 L<< $result->create_related|DBIx::Class::Relationship::Base/create_related >>,
238 the coderef must not only return as its second such a "simple" condition
239 hashref which does not depend on joins being available, but the hashref must
240 contain only plain values/deflatable objects, such that the result can be
241 passed directly to L<DBIx::Class::Relationship::Base/set_from_related>. For
242 instance the C<year> constraint in the above example prevents the relationship
243 from being used to create related objects (an exception will be thrown).
245 In order to allow the user to go truly crazy when generating a custom C<ON>
246 clause, the C<$args> hashref passed to the subroutine contains some extra
247 metadata. Currently the supplied coderef is executed as:
249 $relationship_info->{cond}->({
250 self_resultsource => The resultsource instance on which rel_name is registered
251 rel_name => The relationship name (does *NOT* always match foreign_alias)
253 self_alias => The alias of the invoking resultset
254 foreign_alias => The alias of the to-be-joined resultset (does *NOT* always match rel_name)
256 # only one of these (or none at all) will ever be supplied to aid in the
257 # construction of a join-free condition
258 self_result_object => The invocant object itself in case of a $result_object->$rel_name( ... ) call
259 foreign_result_object => The related object in case of $result_object->set_from_related( $rel_name, $foreign_result_object )
261 # deprecated inconsistent names, will be forever available for legacy code
262 self_rowobj => Old deprecated slot for self_result_object
263 foreign_relname => Old deprecated slot for rel_name
268 The L<standard ResultSet attributes|DBIx::Class::ResultSet/ATTRIBUTES> may
269 be used as relationship attributes. In particular, the 'where' attribute is
270 useful for filtering relationships:
272 __PACKAGE__->has_many( 'valid_users', 'MyApp::Schema::User',
273 { 'foreign.user_id' => 'self.user_id' },
274 { where => { valid => 1 } }
277 The following attributes are also valid:
283 Explicitly specifies the type of join to use in the relationship. Any SQL
284 join type is valid, e.g. C<LEFT> or C<RIGHT>. It will be placed in the SQL
285 command immediately before C<JOIN>.
287 =item proxy =E<gt> $column | \@columns | \%column
289 The 'proxy' attribute can be used to retrieve values, and to perform
290 updates if the relationship has 'cascade_update' set. The 'might_have'
291 and 'has_one' relationships have this set by default; if you want a proxy
292 to update across a 'belongs_to' relationship, you must set the attribute
299 An arrayref containing a list of accessors in the foreign class to create in
300 the main class. If, for example, you do the following:
302 MyApp::Schema::CD->might_have(liner_notes => 'MyApp::Schema::LinerNotes',
304 proxy => [ qw/notes/ ],
307 Then, assuming MyApp::Schema::LinerNotes has an accessor named notes, you can do:
309 my $cd = MyApp::Schema::CD->find(1);
310 $cd->notes('Notes go here'); # set notes -- LinerNotes object is
311 # created if it doesn't exist
313 For a 'belongs_to relationship, note the 'cascade_update':
315 MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd,
316 { proxy => ['title'], cascade_update => 1 }
318 $track->title('New Title');
319 $track->update; # updates title in CD
323 A hashref where each key is the accessor you want installed in the main class,
324 and its value is the name of the original in the foreign class.
326 MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd', {
327 proxy => { cd_title => 'title' },
330 This will create an accessor named C<cd_title> on the C<$track> result object.
334 NOTE: you can pass a nested struct too, for example:
336 MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd', {
337 proxy => [ 'year', { cd_title => 'title' } ],
342 Specifies the type of accessor that should be created for the relationship.
343 Valid values are C<single> (for when there is only a single related object),
344 C<multi> (when there can be many), and C<filter> (for when there is a single
345 related object, but you also want the relationship accessor to double as
346 a column accessor). For C<multi> accessors, an add_to_* method is also
347 created, which calls C<create_related> for the relationship.
349 =item is_foreign_key_constraint
351 If you are using L<SQL::Translator> to create SQL for you and you find that it
352 is creating constraints where it shouldn't, or not creating them where it
353 should, set this attribute to a true or false value to override the detection
354 of when to create constraints.
358 If C<cascade_copy> is true on a C<has_many> relationship for an
359 object, then when you copy the object all the related objects will
360 be copied too. To turn this behaviour off, pass C<< cascade_copy => 0 >>
361 in the C<$attr> hashref.
363 The behaviour defaults to C<< cascade_copy => 1 >> for C<has_many>
368 By default, DBIx::Class cascades deletes across C<has_many>,
369 C<has_one> and C<might_have> relationships. You can disable this
370 behaviour on a per-relationship basis by supplying
371 C<< cascade_delete => 0 >> in the relationship attributes.
373 The cascaded operations are performed after the requested delete,
374 so if your database has a constraint on the relationship, it will
375 have deleted/updated the related records or raised an exception
376 before DBIx::Class gets to perform the cascaded operation.
380 By default, DBIx::Class cascades updates across C<has_one> and
381 C<might_have> relationships. You can disable this behaviour on a
382 per-relationship basis by supplying C<< cascade_update => 0 >> in
383 the relationship attributes.
385 The C<belongs_to> relationship does not update across relationships
386 by default, so if you have a 'proxy' attribute on a belongs_to and want to
387 use 'update' on it, you muse set C<< cascade_update => 1 >>.
389 This is not a RDMS style cascade update - it purely means that when
390 an object has update called on it, all the related objects also
391 have update called. It will not change foreign keys automatically -
392 you must arrange to do this yourself.
394 =item on_delete / on_update
396 If you are using L<SQL::Translator> to create SQL for you, you can use these
397 attributes to explicitly set the desired C<ON DELETE> or C<ON UPDATE> constraint
398 type. If not supplied the SQLT parser will attempt to infer the constraint type by
399 interrogating the attributes of the B<opposite> relationship. For any 'multi'
400 relationship with C<< cascade_delete => 1 >>, the corresponding belongs_to
401 relationship will be created with an C<ON DELETE CASCADE> constraint. For any
402 relationship bearing C<< cascade_copy => 1 >> the resulting belongs_to constraint
403 will be C<ON UPDATE CASCADE>. If you wish to disable this autodetection, and just
404 use the RDBMS' default constraint type, pass C<< on_delete => undef >> or
405 C<< on_delete => '' >>, and the same for C<on_update> respectively.
409 Tells L<SQL::Translator> that the foreign key constraint it creates should be
410 deferrable. In other words, the user may request that the constraint be ignored
411 until the end of the transaction. Currently, only the PostgreSQL producer
412 actually supports this.
416 Tells L<SQL::Translator> to add an index for this constraint. Can also be
417 specified globally in the args to L<DBIx::Class::Schema/deploy> or
418 L<DBIx::Class::Schema/create_ddl_dir>. Default is on, set to 0 to disable.
422 =head2 register_relationship
426 =item Arguments: $rel_name, $rel_info
430 Registers a relationship on the class. This is called internally by
431 DBIx::Class::ResultSourceProxy to set up Accessors and Proxies.
435 sub register_relationship { }
437 =head2 related_resultset
441 =item Arguments: $rel_name
443 =item Return Value: L<$related_resultset|DBIx::Class::ResultSet>
447 $rs = $cd->related_resultset('artist');
449 Returns a L<DBIx::Class::ResultSet> for the relationship named
452 =head2 $relationship_accessor
456 =item Arguments: none
458 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | L<$related_resultset|DBIx::Class::ResultSet> | undef
462 # These pairs do the same thing
463 $result = $cd->related_resultset('artist')->single; # has_one relationship
464 $result = $cd->artist;
465 $rs = $cd->related_resultset('tracks'); # has_many relationship
468 This is the recommended way to traverse through relationships, based
469 on the L</accessor> name given in the relationship definition.
471 This will return either a L<Result|DBIx::Class::Manual::ResultClass> or a
472 L<ResultSet|DBIx::Class::ResultSet>, depending on if the relationship is
473 C<single> (returns only one row) or C<multi> (returns many rows). The
474 method may also return C<undef> if the relationship doesn't exist for
475 this instance (like in the case of C<might_have> relationships).
479 sub related_resultset {
482 $self->throw_exception("Can't call *_related as class methods")
487 return $self->{related_resultsets}{$rel}
488 if defined $self->{related_resultsets}{$rel};
490 return $self->{related_resultsets}{$rel} = do {
492 my $rsrc = $self->result_source;
494 my $rel_info = $rsrc->relationship_info($rel)
495 or $self->throw_exception( "No such relationship '$rel'" );
497 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
498 $attrs = { %{$rel_info->{attrs} || {}}, %$attrs };
500 $self->throw_exception( "Invalid query: @_" )
501 if (@_ > 1 && (@_ % 2 == 1));
502 my $query = ((@_ > 1) ? {@_} : shift);
504 # condition resolution may fail if an incomplete master-object prefetch
505 # is encountered - that is ok during prefetch construction (not yet in_storage)
506 my ($cond, $is_crosstable) = try {
507 $rsrc->_resolve_condition( $rel_info->{cond}, $rel, $self, $rel )
510 $self->throw_exception ($_) if $self->in_storage;
511 UNRESOLVABLE_CONDITION; # RV, no return()
514 # keep in mind that the following if() block is part of a do{} - no return()s!!!
515 if ($is_crosstable and ref $rel_info->{cond} eq 'CODE') {
517 # A WHOREIFFIC hack to reinvoke the entire condition resolution
518 # with the correct alias. Another way of doing this involves a
519 # lot of state passing around, and the @_ positions are already
520 # mapped out, making this crap a less icky option.
522 # The point of this exercise is to retain the spirit of the original
523 # $obj->search_related($rel) where the resulting rset will have the
524 # root alias as 'me', instead of $rel (as opposed to invoking
525 # $rs->search_related)
527 local $rsrc->{_relationships}{me} = $rsrc->{_relationships}{$rel}; # make the fake 'me' rel
528 my $obj_table_alias = lc($rsrc->source_name) . '__row';
529 $obj_table_alias =~ s/\W+/_/g;
531 $rsrc->resultset->search(
532 $self->ident_condition($obj_table_alias),
533 { alias => $obj_table_alias },
534 )->search_related('me', $query, $attrs)
537 # FIXME - this conditional doesn't seem correct - got to figure out
538 # at some point what it does. Also the entire UNRESOLVABLE_CONDITION
539 # business seems shady - we could simply not query *at all*
540 if ($cond eq UNRESOLVABLE_CONDITION) {
541 my $reverse = $rsrc->reverse_relationship_info($rel);
542 foreach my $rev_rel (keys %$reverse) {
543 if ($reverse->{$rev_rel}{attrs}{accessor} && $reverse->{$rev_rel}{attrs}{accessor} eq 'multi') {
544 weaken($attrs->{related_objects}{$rev_rel}[0] = $self);
546 weaken($attrs->{related_objects}{$rev_rel} = $self);
550 elsif (ref $cond eq 'ARRAY') {
552 if (ref $_ eq 'HASH') {
554 foreach my $key (keys %$_) {
555 my $newkey = $key !~ /\./ ? "me.$key" : $key;
556 $hash->{$newkey} = $_->{$key};
564 elsif (ref $cond eq 'HASH') {
565 foreach my $key (grep { ! /\./ } keys %$cond) {
566 $cond->{"me.$key"} = delete $cond->{$key};
570 $query = ($query ? { '-and' => [ $cond, $query ] } : $cond);
571 $rsrc->related_source($rel)->resultset->search(
578 =head2 search_related
582 =item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
584 =item Return Value: L<$resultset|DBIx::Class::ResultSet> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
588 Run a search on a related resultset. The search will be restricted to the
589 results represented by the L<DBIx::Class::ResultSet> it was called
592 See L<DBIx::Class::ResultSet/search_related> for more information.
597 return shift->related_resultset(shift)->search(@_);
600 =head2 search_related_rs
602 This method works exactly the same as search_related, except that
603 it guarantees a resultset, even in list context.
607 sub search_related_rs {
608 return shift->related_resultset(shift)->search_rs(@_);
615 =item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
617 =item Return Value: $count
621 Returns the count of all the rows in the related resultset, restricted by the
622 current result or where conditions.
627 shift->search_related(@_)->count;
634 =item Arguments: $rel_name, \%col_data
636 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
640 Create a new result object of the related foreign class. It will magically set
641 any foreign key columns of the new object to the related primary key columns
642 of the source object for you. The newly created result will not be saved into
643 your storage until you call L<DBIx::Class::Row/insert> on it.
648 my ($self, $rel, $data) = @_;
650 return $self->search_related($rel)->new_result( $self->result_source->_resolve_relationship_condition (
651 infer_values_based_on => $data,
653 self_result_object => $self,
654 foreign_alias => $rel,
656 )->{inferred_values} );
659 =head2 create_related
663 =item Arguments: $rel_name, \%col_data
665 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
669 my $result = $obj->create_related($rel_name, \%col_data);
671 Creates a new result object, similarly to new_related, and also inserts the
672 result's data into your storage medium. See the distinction between C<create>
673 and C<new> in L<DBIx::Class::ResultSet> for details.
680 my $obj = $self->new_related($rel, @_)->insert;
681 delete $self->{related_resultsets}->{$rel};
689 =item Arguments: $rel_name, \%col_data | @pk_values, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
691 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
695 my $result = $obj->find_related($rel_name, \%col_data);
697 Attempt to find a related object using its primary key or unique constraints.
698 See L<DBIx::Class::ResultSet/find> for details.
703 #my ($self, $rel, @args) = @_;
704 return shift->search_related(shift)->find(@_);
707 =head2 find_or_new_related
711 =item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
713 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
717 Find a result object of a related class. See L<DBIx::Class::ResultSet/find_or_new>
722 sub find_or_new_related {
724 my $obj = $self->find_related(@_);
725 return defined $obj ? $obj : $self->new_related(@_);
728 =head2 find_or_create_related
732 =item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
734 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
738 Find or create a result object of a related class. See
739 L<DBIx::Class::ResultSet/find_or_create> for details.
743 sub find_or_create_related {
745 my $obj = $self->find_related(@_);
746 return (defined($obj) ? $obj : $self->create_related(@_));
749 =head2 update_or_create_related
753 =item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
755 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
759 Update or create a result object of a related class. See
760 L<DBIx::Class::ResultSet/update_or_create> for details.
764 sub update_or_create_related {
765 #my ($self, $rel, @args) = @_;
766 shift->related_resultset(shift)->update_or_create(@_);
769 =head2 set_from_related
773 =item Arguments: $rel_name, L<$result|DBIx::Class::Manual::ResultClass>
775 =item Return Value: not defined
779 $book->set_from_related('author', $author_obj);
780 $book->author($author_obj); ## same thing
782 Set column values on the current object, using related values from the given
783 related object. This is used to associate previously separate objects, for
784 example, to set the correct author for a book, find the Author object, then
785 call set_from_related on the book.
787 This is called internally when you pass existing objects as values to
788 L<DBIx::Class::ResultSet/create>, or pass an object to a belongs_to accessor.
790 The columns are only set in the local copy of the object, call L</update> to
791 set them in the storage.
795 sub set_from_related {
796 my ($self, $rel, $f_obj) = @_;
798 $self->set_columns( $self->result_source->_resolve_relationship_condition (
799 infer_values_based_on => {},
801 foreign_result_object => $f_obj,
802 foreign_alias => $rel,
804 )->{inferred_values} );
809 =head2 update_from_related
813 =item Arguments: $rel_name, L<$result|DBIx::Class::Manual::ResultClass>
815 =item Return Value: not defined
819 $book->update_from_related('author', $author_obj);
821 The same as L</"set_from_related">, but the changes are immediately updated
826 sub update_from_related {
828 $self->set_from_related(@_);
832 =head2 delete_related
836 =item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
838 =item Return Value: $underlying_storage_rv
842 Delete any related row, subject to the given conditions. Internally, this
845 $self->search_related(@_)->delete
847 And returns the result of that.
853 my $obj = $self->search_related(@_)->delete;
854 delete $self->{related_resultsets}->{$_[0]};
860 B<Currently only available for C<has_many>, C<many_to_many> and 'multi' type
863 =head3 has_many / multi
867 =item Arguments: \%col_data
869 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
873 Creates/inserts a new result object. Internally, this calls:
875 $self->create_related($rel, @_)
877 And returns the result of that.
883 =item Arguments: (\%col_data | L<$result|DBIx::Class::Manual::ResultClass>), \%link_col_data?
885 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
889 my $role = $schema->resultset('Role')->find(1);
890 $actor->add_to_roles($role);
891 # creates a My::DBIC::Schema::ActorRoles linking table result object
893 $actor->add_to_roles({ name => 'lead' }, { salary => 15_000_000 });
894 # creates a new My::DBIC::Schema::Role result object and the linking table
895 # object with an extra column in the link
897 Adds a linking table object. If the first argument is a hash reference, the
898 related object is created first with the column values in the hash. If an object
899 reference is given, just the linking table object is created. In either case,
900 any additional column values for the linking table object can be specified in
903 See L<DBIx::Class::Relationship/many_to_many> for additional details.
907 B<Currently only available for C<many_to_many> relationships.>
911 =item Arguments: (\@hashrefs_of_col_data | L<\@result_objs|DBIx::Class::Manual::ResultClass>), $link_vals?
913 =item Return Value: not defined
917 my $actor = $schema->resultset('Actor')->find(1);
918 my @roles = $schema->resultset('Role')->search({ role =>
919 { '-in' => ['Fred', 'Barney'] } } );
921 $actor->set_roles(\@roles);
922 # Replaces all of $actor's previous roles with the two named
924 $actor->set_roles(\@roles, { salary => 15_000_000 });
925 # Sets a column in the link table for all roles
928 Replace all the related objects with the given reference to a list of
929 objects. This does a C<delete> B<on the link table resultset> to remove the
930 association between the current object and all related objects, then calls
931 C<add_to_$rel> repeatedly to link all the new objects.
933 Note that this means that this method will B<not> delete any objects in the
934 table on the right side of the relation, merely that it will delete the link
937 Due to a mistake in the original implementation of this method, it will also
938 accept a list of objects or hash references. This is B<deprecated> and will be
939 removed in a future version.
941 =head2 remove_from_$rel
943 B<Currently only available for C<many_to_many> relationships.>
947 =item Arguments: L<$result|DBIx::Class::Manual::ResultClass>
949 =item Return Value: not defined
953 my $role = $schema->resultset('Role')->find(1);
954 $actor->remove_from_roles($role);
955 # removes $role's My::DBIC::Schema::ActorRoles linking table result object
957 Removes the link between the current object and the related object. Note that
958 the related object itself won't be deleted unless you call ->delete() on
959 it. This method just removes the link between the two objects.
961 =head1 AUTHOR AND CONTRIBUTORS
963 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
967 You may distribute this code under the same terms as Perl itself.