1 package DBIx::Class::Relationship::Base;
6 use base qw/DBIx::Class/;
8 use Scalar::Util qw/weaken blessed/;
14 DBIx::Class::Relationship::Base - Inter-table relationships
18 __PACKAGE__->add_relationship(
19 spiders => 'My::DB::Result::Creatures',
23 "$args->{foreign_alias}.id" => { -ident => "$args->{self_alias}.id" },
24 "$args->{foreign_alias}.type" => 'arachnid'
31 This class provides methods to describe the relationships between the
32 tables in your database model. These are the "bare bones" relationships
33 methods, for predefined ones, look in L<DBIx::Class::Relationship>.
37 =head2 add_relationship
41 =item Arguments: 'relname', 'Foreign::Class', $condition, $attrs
45 __PACKAGE__->add_relationship('relname',
49 Create a custom relationship between one result source and another
50 source, indicated by its class name.
54 The condition argument describes the C<ON> clause of the C<JOIN>
55 expression used to connect the two sources when creating SQL queries.
57 =head4 Simple equality
59 To create simple equality joins, supply a hashref containing the remote
60 table column name as the key(s) prefixed by C<'foreign.'>, and the
61 corresponding local table column name as the value(s) prefixed by C<'self.'>.
62 Both C<foreign> and C<self> are pseudo aliases and must be entered
63 literally. They will be replaced with the actual correct table alias
64 when the SQL is produced.
68 My::Schema::Author->has_many(
69 books => 'My::Schema::Book',
70 { 'foreign.author_id' => 'self.id' }
75 $author_rs->search_related('books')->next
77 will result in the following C<JOIN> clause:
79 ... FROM author me LEFT JOIN book books ON books.author_id = me.id ...
81 This describes a relationship between the C<Author> table and the
82 C<Book> table where the C<Book> table has a column C<author_id>
83 containing the ID value of the C<Author>.
87 My::Schema::Book->has_many(
88 editions => 'My::Schema::Edition',
90 'foreign.publisher_id' => 'self.publisher_id',
91 'foreign.type_id' => 'self.type_id',
97 $book_rs->search_related('editions')->next
99 will result in the C<JOIN> clause:
102 LEFT JOIN edition editions ON
103 editions.publisher_id = me.publisher_id
104 AND editions.type_id = me.type_id ...
106 This describes the relationship from C<Book> to C<Edition>, where the
107 C<Edition> table refers to a publisher and a type (e.g. "paperback"):
109 =head4 Multiple groups of simple equality conditions
111 As is the default in L<SQL::Abstract>, the key-value pairs will be
112 C<AND>ed in the resulting C<JOIN> clause. An C<OR> can be achieved with
113 an arrayref. For example a condition like:
115 My::Schema::Item->has_many(
116 related_item_links => My::Schema::Item::Links,
118 { 'foreign.left_itemid' => 'self.id' },
119 { 'foreign.right_itemid' => 'self.id' },
123 will translate to the following C<JOIN> clause:
125 ... FROM item me JOIN item_relations related_item_links ON
126 related_item_links.left_itemid = me.id
127 OR related_item_links.right_itemid = me.id ...
129 This describes the relationship from C<Item> to C<Item::Links>, where
130 C<Item::Links> is a many-to-many linking table, linking items back to
131 themselves in a peer fashion (without a "parent-child" designation)
133 =head4 Custom join conditions
135 NOTE: The custom join condition specification mechanism is capable of
136 generating JOIN clauses of virtually unlimited complexity. This may limit
137 your ability to traverse some of the more involved relationship chains the
138 way you expect, *and* may bring your RDBMS to its knees. Exercise care
139 when declaring relationships as described here.
141 To specify joins which describe more than a simple equality of column
142 values, the custom join condition coderef syntax can be used. For
145 My::Schema::Artist->has_many(
146 cds_80s => 'My::Schema::CD',
151 "$args->{foreign_alias}.artist" => { -ident => "$args->{self_alias}.artistid" },
152 "$args->{foreign_alias}.year" => { '>', "1979", '<', "1990" },
159 $artist_rs->search_related('cds_80s')->next;
161 will result in the C<JOIN> clause:
163 ... FROM artist me LEFT JOIN cd cds_80s ON
164 cds_80s.artist = me.artistid
168 with the bind values:
172 C<< $args->{foreign_alias} >> and C<< $args->{self_alias} >> are supplied the
173 same values that would be otherwise substituted for C<foreign> and C<self>
174 in the simple hashref syntax case.
176 The coderef is expected to return a valid L<SQL::Abstract> query-structure, just
177 like what one would supply as the first argument to
178 L<DBIx::Class::ResultSet/search>. The return value will be passed directly to
179 L<SQL::Abstract> and the resulting SQL will be used verbatim as the C<ON>
180 clause of the C<JOIN> statement associated with this relationship.
182 While every coderef-based condition must return a valid C<ON> clause, it may
183 elect to additionally return a simplified join-free condition hashref when
184 invoked as C<< $result->relationship >>, as opposed to
185 C<< $rs->related_resultset('relationship') >>. In this case C<$result> is
186 passed to the coderef as C<< $args->{self_rowobj} >>, so a user can do the
194 "$args->{foreign_alias}.artist" => { -ident => "$args->{self_alias}.artistid" },
195 "$args->{foreign_alias}.year" => { '>', "1979", '<', "1990" },
197 $args->{self_rowobj} && {
198 "$args->{foreign_alias}.artist" => $args->{self_rowobj}->artistid,
199 "$args->{foreign_alias}.year" => { '>', "1979", '<', "1990" },
206 my $artist = $schema->resultset("Artist")->find({ id => 4 });
207 $artist->cds_80s->all;
209 Can skip a C<JOIN> altogether and instead produce:
211 SELECT cds_80s.cdid, cds_80s.artist, cds_80s.title, cds_80s.year, cds_80s.genreid, cds_80s.single_track
213 WHERE cds_80s.artist = ?
217 With the bind values:
221 Note that in order to be able to use
222 L<< $result->create_related|DBIx::Class::Relationship::Base/create_related >>,
223 the coderef must not only return as its second such a "simple" condition
224 hashref which does not depend on joins being available, but the hashref must
225 contain only plain values/deflatable objects, such that the result can be
226 passed directly to L<DBIx::Class::Relationship::Base/set_from_related>. For
227 instance the C<year> constraint in the above example prevents the relationship
228 from being used to create related objects (an exception will be thrown).
230 In order to allow the user to go truly crazy when generating a custom C<ON>
231 clause, the C<$args> hashref passed to the subroutine contains some extra
232 metadata. Currently the supplied coderef is executed as:
234 $relationship_info->{cond}->({
235 self_resultsource => The resultsource instance on which rel_name is registered
236 rel_name => The relationship name (does *NOT* always match foreign_alias)
238 self_alias => The alias of the invoking resultset
239 foreign_alias => The alias of the to-be-joined resultset (does *NOT* always match rel_name)
241 self_resultobj => The invocant object itself in case of a $resultobj->$rel_name() call
243 # deprecated inconsistent names, will be forever available for legacy code
244 self_rowobj => Old deprecated slot for self_resultobj
245 foreign_relname => Old deprecated slot for rel_name
250 The L<standard ResultSet attributes|DBIx::Class::ResultSet/ATTRIBUTES> may
251 be used as relationship attributes. In particular, the 'where' attribute is
252 useful for filtering relationships:
254 __PACKAGE__->has_many( 'valid_users', 'MyApp::Schema::User',
255 { 'foreign.user_id' => 'self.user_id' },
256 { where => { valid => 1 } }
259 The following attributes are also valid:
265 Explicitly specifies the type of join to use in the relationship. Any SQL
266 join type is valid, e.g. C<LEFT> or C<RIGHT>. It will be placed in the SQL
267 command immediately before C<JOIN>.
269 =item proxy =E<gt> $column | \@columns | \%column
271 The 'proxy' attribute can be used to retrieve values, and to perform
272 updates if the relationship has 'cascade_update' set. The 'might_have'
273 and 'has_one' relationships have this set by default; if you want a proxy
274 to update across a 'belongs_to' relationship, you must set the attribute
281 An arrayref containing a list of accessors in the foreign class to create in
282 the main class. If, for example, you do the following:
284 MyApp::Schema::CD->might_have(liner_notes => 'MyApp::Schema::LinerNotes',
286 proxy => [ qw/notes/ ],
289 Then, assuming MyApp::Schema::LinerNotes has an accessor named notes, you can do:
291 my $cd = MyApp::Schema::CD->find(1);
292 $cd->notes('Notes go here'); # set notes -- LinerNotes object is
293 # created if it doesn't exist
295 For a 'belongs_to relationship, note the 'cascade_update':
297 MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd,
298 { proxy => ['title'], cascade_update => 1 }
300 $track->title('New Title');
301 $track->update; # updates title in CD
305 A hashref where each key is the accessor you want installed in the main class,
306 and its value is the name of the original in the foreign class.
308 MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd', {
309 proxy => { cd_title => 'title' },
312 This will create an accessor named C<cd_title> on the C<$track> result object.
316 NOTE: you can pass a nested struct too, for example:
318 MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd', {
319 proxy => [ 'year', { cd_title => 'title' } ],
324 Specifies the type of accessor that should be created for the relationship.
325 Valid values are C<single> (for when there is only a single related object),
326 C<multi> (when there can be many), and C<filter> (for when there is a single
327 related object, but you also want the relationship accessor to double as
328 a column accessor). For C<multi> accessors, an add_to_* method is also
329 created, which calls C<create_related> for the relationship.
331 =item is_foreign_key_constraint
333 If you are using L<SQL::Translator> to create SQL for you and you find that it
334 is creating constraints where it shouldn't, or not creating them where it
335 should, set this attribute to a true or false value to override the detection
336 of when to create constraints.
340 If C<cascade_copy> is true on a C<has_many> relationship for an
341 object, then when you copy the object all the related objects will
342 be copied too. To turn this behaviour off, pass C<< cascade_copy => 0 >>
343 in the C<$attr> hashref.
345 The behaviour defaults to C<< cascade_copy => 1 >> for C<has_many>
350 By default, DBIx::Class cascades deletes across C<has_many>,
351 C<has_one> and C<might_have> relationships. You can disable this
352 behaviour on a per-relationship basis by supplying
353 C<< cascade_delete => 0 >> in the relationship attributes.
355 The cascaded operations are performed after the requested delete,
356 so if your database has a constraint on the relationship, it will
357 have deleted/updated the related records or raised an exception
358 before DBIx::Class gets to perform the cascaded operation.
362 By default, DBIx::Class cascades updates across C<has_one> and
363 C<might_have> relationships. You can disable this behaviour on a
364 per-relationship basis by supplying C<< cascade_update => 0 >> in
365 the relationship attributes.
367 The C<belongs_to> relationship does not update across relationships
368 by default, so if you have a 'proxy' attribute on a belongs_to and want to
369 use 'update' on it, you muse set C<< cascade_update => 1 >>.
371 This is not a RDMS style cascade update - it purely means that when
372 an object has update called on it, all the related objects also
373 have update called. It will not change foreign keys automatically -
374 you must arrange to do this yourself.
376 =item on_delete / on_update
378 If you are using L<SQL::Translator> to create SQL for you, you can use these
379 attributes to explicitly set the desired C<ON DELETE> or C<ON UPDATE> constraint
380 type. If not supplied the SQLT parser will attempt to infer the constraint type by
381 interrogating the attributes of the B<opposite> relationship. For any 'multi'
382 relationship with C<< cascade_delete => 1 >>, the corresponding belongs_to
383 relationship will be created with an C<ON DELETE CASCADE> constraint. For any
384 relationship bearing C<< cascade_copy => 1 >> the resulting belongs_to constraint
385 will be C<ON UPDATE CASCADE>. If you wish to disable this autodetection, and just
386 use the RDBMS' default constraint type, pass C<< on_delete => undef >> or
387 C<< on_delete => '' >>, and the same for C<on_update> respectively.
391 Tells L<SQL::Translator> that the foreign key constraint it creates should be
392 deferrable. In other words, the user may request that the constraint be ignored
393 until the end of the transaction. Currently, only the PostgreSQL producer
394 actually supports this.
398 Tells L<SQL::Translator> to add an index for this constraint. Can also be
399 specified globally in the args to L<DBIx::Class::Schema/deploy> or
400 L<DBIx::Class::Schema/create_ddl_dir>. Default is on, set to 0 to disable.
404 =head2 register_relationship
408 =item Arguments: $rel_name, $rel_info
412 Registers a relationship on the class. This is called internally by
413 DBIx::Class::ResultSourceProxy to set up Accessors and Proxies.
417 sub register_relationship { }
419 =head2 related_resultset
423 =item Arguments: $rel_name
425 =item Return Value: L<$related_resultset|DBIx::Class::ResultSet>
429 $rs = $cd->related_resultset('artist');
431 Returns a L<DBIx::Class::ResultSet> for the relationship named
434 =head2 $relationship_accessor
438 =item Arguments: none
440 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | L<$related_resultset|DBIx::Class::ResultSet> | undef
444 # These pairs do the same thing
445 $result = $cd->related_resultset('artist')->single; # has_one relationship
446 $result = $cd->artist;
447 $rs = $cd->related_resultset('tracks'); # has_many relationship
450 This is the recommended way to traverse through relationships, based
451 on the L</accessor> name given in the relationship definition.
453 This will return either a L<Result|DBIx::Class::Manual::ResultClass> or a
454 L<ResultSet|DBIx::Class::ResultSet>, depending on if the relationship is
455 C<single> (returns only one row) or C<multi> (returns many rows). The
456 method may also return C<undef> if the relationship doesn't exist for
457 this instance (like in the case of C<might_have> relationships).
461 sub related_resultset {
464 $self->throw_exception("Can't call *_related as class methods")
469 return $self->{related_resultsets}{$rel}
470 if defined $self->{related_resultsets}{$rel};
472 return $self->{related_resultsets}{$rel} = do {
474 my $rel_info = $self->relationship_info($rel)
475 or $self->throw_exception( "No such relationship '$rel'" );
477 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
478 $attrs = { %{$rel_info->{attrs} || {}}, %$attrs };
480 $self->throw_exception( "Invalid query: @_" )
481 if (@_ > 1 && (@_ % 2 == 1));
482 my $query = ((@_ > 1) ? {@_} : shift);
484 my $rsrc = $self->result_source;
486 # condition resolution may fail if an incomplete master-object prefetch
487 # is encountered - that is ok during prefetch construction (not yet in_storage)
488 my ($cond, $is_crosstable) = try {
489 $rsrc->_resolve_condition( $rel_info->{cond}, $rel, $self, $rel )
492 $self->throw_exception ($_) if $self->in_storage;
493 $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION; # RV, no return()
496 # keep in mind that the following if() block is part of a do{} - no return()s!!!
497 if ($is_crosstable and ref $rel_info->{cond} eq 'CODE') {
499 # A WHOREIFFIC hack to reinvoke the entire condition resolution
500 # with the correct alias. Another way of doing this involves a
501 # lot of state passing around, and the @_ positions are already
502 # mapped out, making this crap a less icky option.
504 # The point of this exercise is to retain the spirit of the original
505 # $obj->search_related($rel) where the resulting rset will have the
506 # root alias as 'me', instead of $rel (as opposed to invoking
507 # $rs->search_related)
509 local $rsrc->{_relationships}{me} = $rsrc->{_relationships}{$rel}; # make the fake 'me' rel
510 my $obj_table_alias = lc($rsrc->source_name) . '__row';
511 $obj_table_alias =~ s/\W+/_/g;
513 $rsrc->resultset->search(
514 $self->ident_condition($obj_table_alias),
515 { alias => $obj_table_alias },
516 )->search_related('me', $query, $attrs)
519 # FIXME - this conditional doesn't seem correct - got to figure out
520 # at some point what it does. Also the entire UNRESOLVABLE_CONDITION
521 # business seems shady - we could simply not query *at all*
522 if ($cond eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
523 my $reverse = $rsrc->reverse_relationship_info($rel);
524 foreach my $rev_rel (keys %$reverse) {
525 if ($reverse->{$rev_rel}{attrs}{accessor} && $reverse->{$rev_rel}{attrs}{accessor} eq 'multi') {
526 weaken($attrs->{related_objects}{$rev_rel}[0] = $self);
528 weaken($attrs->{related_objects}{$rev_rel} = $self);
532 elsif (ref $cond eq 'ARRAY') {
534 if (ref $_ eq 'HASH') {
536 foreach my $key (keys %$_) {
537 my $newkey = $key !~ /\./ ? "me.$key" : $key;
538 $hash->{$newkey} = $_->{$key};
546 elsif (ref $cond eq 'HASH') {
547 foreach my $key (grep { ! /\./ } keys %$cond) {
548 $cond->{"me.$key"} = delete $cond->{$key};
552 $query = ($query ? { '-and' => [ $cond, $query ] } : $cond);
553 $rsrc->related_source($rel)->resultset->search(
560 =head2 search_related
564 =item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
566 =item Return Value: L<$resultset|DBIx::Class::ResultSet> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
570 Run a search on a related resultset. The search will be restricted to the
571 results represented by the L<DBIx::Class::ResultSet> it was called
574 See L<DBIx::Class::ResultSet/search_related> for more information.
579 return shift->related_resultset(shift)->search(@_);
582 =head2 search_related_rs
584 This method works exactly the same as search_related, except that
585 it guarantees a resultset, even in list context.
589 sub search_related_rs {
590 return shift->related_resultset(shift)->search_rs(@_);
597 =item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
599 =item Return Value: $count
603 Returns the count of all the rows in the related resultset, restricted by the
604 current result or where conditions.
609 shift->search_related(@_)->count;
616 =item Arguments: $rel_name, \%col_data
618 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
622 Create a new result object of the related foreign class. It will magically set
623 any foreign key columns of the new object to the related primary key columns
624 of the source object for you. The newly created result will not be saved into
625 your storage until you call L<DBIx::Class::Row/insert> on it.
630 my ($self, $rel, $values) = @_;
632 # FIXME - this is a bad position for this (also an identical copy in
633 # set_from_related), but I have no saner way to hook, and I absolutely
634 # want this to throw at least for coderefs, instead of the "insert a NULL
635 # when it gets hard" insanity --ribasushi
637 # sanity check - currently throw when a complex coderef rel is encountered
638 # FIXME - should THROW MOAR!
640 if (ref $self) { # cdbi calls this as a class method, /me vomits
642 my $rsrc = $self->result_source;
643 my $rel_info = $rsrc->relationship_info($rel)
644 or $self->throw_exception( "No such relationship '$rel'" );
645 my (undef, $crosstable, $nonequality_foreign_columns) = $rsrc->_resolve_condition (
646 $rel_info->{cond}, $rel, $self, $rel
649 $self->throw_exception("Relationship '$rel' does not resolve to a join-free condition fragment")
653 $nonequality_foreign_columns
655 my @unspecified_rel_condition_chunks = grep { ! exists $values->{$_} } @$nonequality_foreign_columns
657 $self->throw_exception(sprintf (
658 "Custom relationship '%s' not definitive - returns conditions instead of values for column(s): %s",
660 map { "'$_'" } @unspecified_rel_condition_chunks
665 return $self->search_related($rel)->new_result($values);
668 =head2 create_related
672 =item Arguments: $rel_name, \%col_data
674 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
678 my $result = $obj->create_related($rel_name, \%col_data);
680 Creates a new result object, similarly to new_related, and also inserts the
681 result's data into your storage medium. See the distinction between C<create>
682 and C<new> in L<DBIx::Class::ResultSet> for details.
689 my $obj = $self->new_related($rel, @_)->insert;
690 delete $self->{related_resultsets}->{$rel};
698 =item Arguments: $rel_name, \%col_data | @pk_values, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
700 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
704 my $result = $obj->find_related($rel_name, \%col_data);
706 Attempt to find a related object using its primary key or unique constraints.
707 See L<DBIx::Class::ResultSet/find> for details.
712 #my ($self, $rel, @args) = @_;
713 return shift->search_related(shift)->find(@_);
716 =head2 find_or_new_related
720 =item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
722 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
726 Find a result object of a related class. See L<DBIx::Class::ResultSet/find_or_new>
731 sub find_or_new_related {
733 my $obj = $self->find_related(@_);
734 return defined $obj ? $obj : $self->new_related(@_);
737 =head2 find_or_create_related
741 =item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
743 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
747 Find or create a result object of a related class. See
748 L<DBIx::Class::ResultSet/find_or_create> for details.
752 sub find_or_create_related {
754 my $obj = $self->find_related(@_);
755 return (defined($obj) ? $obj : $self->create_related(@_));
758 =head2 update_or_create_related
762 =item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
764 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
768 Update or create a result object of a related class. See
769 L<DBIx::Class::ResultSet/update_or_create> for details.
773 sub update_or_create_related {
774 #my ($self, $rel, @args) = @_;
775 shift->related_resultset(shift)->update_or_create(@_);
778 =head2 set_from_related
782 =item Arguments: $rel_name, L<$result|DBIx::Class::Manual::ResultClass>
784 =item Return Value: not defined
788 $book->set_from_related('author', $author_obj);
789 $book->author($author_obj); ## same thing
791 Set column values on the current object, using related values from the given
792 related object. This is used to associate previously separate objects, for
793 example, to set the correct author for a book, find the Author object, then
794 call set_from_related on the book.
796 This is called internally when you pass existing objects as values to
797 L<DBIx::Class::ResultSet/create>, or pass an object to a belongs_to accessor.
799 The columns are only set in the local copy of the object, call L</update> to
800 set them in the storage.
804 sub set_from_related {
805 my ($self, $rel, $f_obj) = @_;
807 my $rsrc = $self->result_source;
808 my $rel_info = $rsrc->relationship_info($rel)
809 or $self->throw_exception( "No such relationship '$rel'" );
811 if (defined $f_obj) {
812 my $f_class = $rel_info->{class};
813 $self->throw_exception( "Object '$f_obj' isn't a ".$f_class )
814 unless blessed $f_obj and $f_obj->isa($f_class);
818 # FIXME - this is a bad position for this (also an identical copy in
819 # new_related), but I have no saner way to hook, and I absolutely
820 # want this to throw at least for coderefs, instead of the "insert a NULL
821 # when it gets hard" insanity --ribasushi
823 # sanity check - currently throw when a complex coderef rel is encountered
824 # FIXME - should THROW MOAR!
825 my ($cond, $crosstable, $nonequality_foreign_columns) = $rsrc->_resolve_condition (
826 $rel_info->{cond}, $f_obj, $rel, $rel
828 $self->throw_exception("Relationship '$rel' does not resolve to a join-free condition fragment")
831 $self->throw_exception(sprintf (
832 "Custom relationship '%s' not definitive - returns conditions instead of values for column(s): %s",
834 map { "'$_'" } @$nonequality_foreign_columns
835 )) if $nonequality_foreign_columns;
837 $self->set_columns($cond);
842 =head2 update_from_related
846 =item Arguments: $rel_name, L<$result|DBIx::Class::Manual::ResultClass>
848 =item Return Value: not defined
852 $book->update_from_related('author', $author_obj);
854 The same as L</"set_from_related">, but the changes are immediately updated
859 sub update_from_related {
861 $self->set_from_related(@_);
865 =head2 delete_related
869 =item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
871 =item Return Value: $underlying_storage_rv
875 Delete any related row, subject to the given conditions. Internally, this
878 $self->search_related(@_)->delete
880 And returns the result of that.
886 my $obj = $self->search_related(@_)->delete;
887 delete $self->{related_resultsets}->{$_[0]};
893 B<Currently only available for C<has_many>, C<many_to_many> and 'multi' type
896 =head3 has_many / multi
900 =item Arguments: \%col_data
902 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
906 Creates/inserts a new result object. Internally, this calls:
908 $self->create_related($rel, @_)
910 And returns the result of that.
916 =item Arguments: (\%col_data | L<$result|DBIx::Class::Manual::ResultClass>), \%link_col_data?
918 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
922 my $role = $schema->resultset('Role')->find(1);
923 $actor->add_to_roles($role);
924 # creates a My::DBIC::Schema::ActorRoles linking table result object
926 $actor->add_to_roles({ name => 'lead' }, { salary => 15_000_000 });
927 # creates a new My::DBIC::Schema::Role result object and the linking table
928 # object with an extra column in the link
930 Adds a linking table object. If the first argument is a hash reference, the
931 related object is created first with the column values in the hash. If an object
932 reference is given, just the linking table object is created. In either case,
933 any additional column values for the linking table object can be specified in
936 See L<DBIx::Class::Relationship/many_to_many> for additional details.
940 B<Currently only available for C<many_to_many> relationships.>
944 =item Arguments: (\@hashrefs_of_col_data | L<\@result_objs|DBIx::Class::Manual::ResultClass>), $link_vals?
946 =item Return Value: not defined
950 my $actor = $schema->resultset('Actor')->find(1);
951 my @roles = $schema->resultset('Role')->search({ role =>
952 { '-in' => ['Fred', 'Barney'] } } );
954 $actor->set_roles(\@roles);
955 # Replaces all of $actor's previous roles with the two named
957 $actor->set_roles(\@roles, { salary => 15_000_000 });
958 # Sets a column in the link table for all roles
961 Replace all the related objects with the given reference to a list of
962 objects. This does a C<delete> B<on the link table resultset> to remove the
963 association between the current object and all related objects, then calls
964 C<add_to_$rel> repeatedly to link all the new objects.
966 Note that this means that this method will B<not> delete any objects in the
967 table on the right side of the relation, merely that it will delete the link
970 Due to a mistake in the original implementation of this method, it will also
971 accept a list of objects or hash references. This is B<deprecated> and will be
972 removed in a future version.
974 =head2 remove_from_$rel
976 B<Currently only available for C<many_to_many> relationships.>
980 =item Arguments: L<$result|DBIx::Class::Manual::ResultClass>
982 =item Return Value: not defined
986 my $role = $schema->resultset('Role')->find(1);
987 $actor->remove_from_roles($role);
988 # removes $role's My::DBIC::Schema::ActorRoles linking table result object
990 Removes the link between the current object and the related object. Note that
991 the related object itself won't be deleted unless you call ->delete() on
992 it. This method just removes the link between the two objects.
994 =head1 AUTHOR AND CONTRIBUTORS
996 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
1000 You may distribute this code under the same terms as Perl itself.