1 package DBIx::Class::Relationship::Base;
6 use base qw/DBIx::Class/;
8 __PACKAGE__->mk_classdata('_relationships', { } );
12 DBIx::Class::Relationship::Base - Inter-table relationships
18 This class provides methods to describe the relationships between the
19 tables in your database model. These are the "bare bones" relationships
20 methods, for predefined ones, look in L<DBIx::Class::Relationship>.
24 =head2 add_relationship
26 =head3 Arguments: ('relname', 'Foreign::Class', $cond, $attrs)
28 __PACKAGE__->add_relationship('relname', 'Foreign::Class', $cond, $attrs);
30 The condition needs to be an SQL::Abstract-style representation of the
31 join between the tables. When resolving the condition for use in a JOIN,
32 keys using the psuedo-table I<foreign> are resolved to mean "the Table on the
33 other side of the relationship", and values using the psuedo-table I<self>
34 are resolved to mean "the Table this class is representing". Other
35 restrictions, such as by value, sub-select and other tables, may also be
36 used. Please check your database for JOIN parameter support.
38 For example, if you're creating a rel from Author to Book, where the Book
39 table has a column author_id containing the ID of the Author row:
41 { 'foreign.author_id' => 'self.id' }
43 will result in the JOIN clause
45 author me JOIN book book ON bar.author_id = me.id
47 You can specify as many foreign => self mappings as necessary. Each key/value
48 pair provided in a hashref will be used as ANDed conditions, to add an ORed
49 condition, use an arrayref of hashrefs. See the L<SQL::Abstract> documentation
52 Valid attributes are as follows:
58 Explicitly specifies the type of join to use in the relationship. Any SQL
59 join type is valid, e.g. C<LEFT> or C<RIGHT>. It will be placed in the SQL
60 command immediately before C<JOIN>.
64 An arrayref containing a list of accessors in the foreign class to create in
65 the main class. If, for example, you do the following:
67 MyDB::Schema::CD->might_have(liner_notes => 'MyDB::Schema::LinerNotes', undef, {
68 proxy => [ qw/notes/ ],
71 Then, assuming MyDB::Schema::LinerNotes has an accessor named notes, you can do:
73 my $cd = MyDB::Schema::CD->find(1);
74 $cd->notes('Notes go here'); # set notes -- LinerNotes object is
75 # created if it doesn't exist
79 Specifies the type of accessor that should be created for the relationship.
80 Valid values are C<single> (for when there is only a single related object),
81 C<multi> (when there can be many), and C<filter> (for when there is a single
82 related object, but you also want the relationship accessor to double as
83 a column accessor). For C<multi> accessors, an add_to_* method is also
84 created, which calls C<create_related> for the relationship.
88 =head2 register_relationship
90 =head3 Arguments: ($relname, $rel_info)
92 Registers a relationship on the class. This is called internally by
93 L<DBIx::Class::ResultSourceProxy> to set up Accessors and Proxies.
97 sub register_relationship { }
99 =head2 related_resultset($name)
101 $rs = $obj->related_resultset('related_table');
103 Returns a L<DBIx::Class::ResultSet> for the relationship named $name.
107 sub related_resultset {
109 $self->throw_exception("Can't call *_related as class methods")
112 my $rel_obj = $self->relationship_info($rel);
113 $self->throw_exception( "No such relationship ${rel}" )
116 return $self->{related_resultsets}{$rel} ||= do {
117 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
118 $attrs = { %{$rel_obj->{attrs} || {}}, %$attrs };
120 $self->throw_exception( "Invalid query: @_" )
121 if (@_ > 1 && (@_ % 2 == 1));
122 my $query = ((@_ > 1) ? {@_} : shift);
124 my $cond = $self->result_source->resolve_condition(
125 $rel_obj->{cond}, $rel, $self
127 if (ref $cond eq 'ARRAY') {
128 $cond = [ map { my $hash;
129 foreach my $key (keys %$_) {
130 my $newkey = $key =~ /\./ ? "me.$key" : $key;
131 $hash->{$newkey} = $_->{$key};
134 foreach my $key (grep { ! /\./ } keys %$cond) {
135 $cond->{"me.$key"} = delete $cond->{$key};
138 $query = ($query ? { '-and' => [ $cond, $query ] } : $cond);
139 $self->result_source->related_source($rel)->resultset->search(
145 =head2 search_related
147 $rs->search_related('relname', $cond, $attrs);
149 Run a search on a related resultset. The search will be restricted to the
150 item or items represented by the L<DBIx::Class::ResultSet> it was called
151 upon. This method can be called on a ResultSet, a Row or a ResultSource class.
156 return shift->related_resultset(shift)->search(@_);
161 $obj->count_related('relname', $cond, $attrs);
163 Returns the count of all the items in the related resultset, restricted by the
164 current item or where conditions. Can be called on a
165 L<DBIx::Classl::Manual::Glossary/"ResultSet"> or a
166 L<DBIx::Class::Manual::Glossary/"Row"> object.
172 return $self->search_related(@_)->count;
177 my $new_obj = $obj->new_related('relname', \%col_data);
179 Create a new item of the related foreign class. If called on a
180 L<DBIx::Class::Manual::Glossary/"Row"> object, it will magically
181 set any primary key values into foreign key columns for you. The newly
182 created item will not be saved into your storage until you call C<insert>
188 my ($self, $rel, $values, $attrs) = @_;
189 return $self->search_related($rel)->new($values, $attrs);
192 =head2 create_related
194 my $new_obj = $obj->create_related('relname', \%col_data);
196 Creates a new item, similarly to new_related, and also inserts the item's data
197 into your storage medium. See the distinction between C<create> and C<new>
198 in L<DBIx::Class::ResultSet> for details.
205 my $obj = $self->search_related($rel)->create(@_);
206 delete $self->{related_resultsets}->{$rel};
212 my $found_item = $obj->find_related('relname', @pri_vals | \%pri_vals);
214 Attempt to find a related object using its primary key or unique constraints.
215 See C<find> in L<DBIx::Class::ResultSet> for details.
222 return $self->search_related($rel)->find(@_);
225 =head2 find_or_create_related
227 my $new_obj = $obj->find_or_create_related('relname', \%col_data);
229 Find or create an item of a related class. See C<find_or_create> in
230 L<DBIx::Class::ResultSet> for details.
234 sub find_or_create_related {
236 return $self->find_related(@_) || $self->create_related(@_);
239 =head2 set_from_related
241 $book->set_from_related('author', $author_obj);
243 Set column values on the current object, using related values from the given
244 related object. This is used to associate previously separate objects, for
245 example, to set the correct author for a book, find the Author object, then
246 call set_from_related on the book.
248 The columns are only set in the local copy of the object, call C<update> to set
253 sub set_from_related {
254 my ($self, $rel, $f_obj) = @_;
255 my $rel_obj = $self->relationship_info($rel);
256 $self->throw_exception( "No such relationship ${rel}" ) unless $rel_obj;
257 my $cond = $rel_obj->{cond};
258 $self->throw_exception(
259 "set_from_related can only handle a hash condition; the ".
260 "condition for $rel is of type ".
261 (ref $cond ? ref $cond : 'plain scalar')
262 ) unless ref $cond eq 'HASH';
263 my $f_class = $self->result_source->schema->class($rel_obj->{class});
264 $self->throw_exception( "Object $f_obj isn't a ".$f_class )
265 unless $f_obj->isa($f_class);
267 $self->result_source->resolve_condition(
268 $rel_obj->{cond}, $f_obj, $rel));
272 =head2 update_from_related
274 $book->update_from_related('author', $author_obj);
276 As C<set_from_related>, but the changes are immediately updated onto your
281 sub update_from_related {
283 $self->set_from_related(@_);
287 =head2 delete_related
289 $obj->delete_related('relname', $cond, $attrs);
291 Delete any related item subject to the given conditions.
297 my $obj = $self->search_related(@_)->delete;
298 delete $self->{related_resultsets}->{$_[0]};
306 Matt S. Trout <mst@shadowcatsystems.co.uk>
310 You may distribute this code under the same terms as Perl itself.