use base qw/DBIx::Class/;
-=head1 NAME
+=head1 NAME
DBIx::Class::Relationship::Base - Inter-table relationships
This class provides methods to describe the relationships between the
tables in your database model. These are the "bare bones" relationships
-methods, for predefined ones, look in L<DBIx::Class::Relationship>.
+methods, for predefined ones, look in L<DBIx::Class::Relationship>.
=head1 METHODS
=head2 add_relationship
-=head3 Arguments: ('relname', 'Foreign::Class', $cond, $attrs)
+=over 4
+
+=item Arguments: 'relname', 'Foreign::Class', $cond, $attrs
+
+=back
__PACKAGE__->add_relationship('relname', 'Foreign::Class', $cond, $attrs);
-The condition needs to be an SQL::Abstract-style representation of the
-join between the tables. When resolving the condition for use in a JOIN,
-keys using the psuedo-table I<foreign> are resolved to mean "the Table on the
-other side of the relationship", and values using the psuedo-table I<self>
+The condition needs to be an L<SQL::Abstract>-style representation of the
+join between the tables. When resolving the condition for use in a C<JOIN>,
+keys using the pseudo-table C<foreign> are resolved to mean "the Table on the
+other side of the relationship", and values using the pseudo-table C<self>
are resolved to mean "the Table this class is representing". Other
restrictions, such as by value, sub-select and other tables, may also be
-used. Please check your database for JOIN parameter support.
+used. Please check your database for C<JOIN> parameter support.
-For example, if you're creating a rel from Author to Book, where the Book
-table has a column author_id containing the ID of the Author row:
+For example, if you're creating a relationship from C<Author> to C<Book>, where
+the C<Book> table has a column C<author_id> containing the ID of the C<Author>
+row:
{ 'foreign.author_id' => 'self.id' }
-will result in the JOIN clause
+will result in the C<JOIN> clause
+
+ author me JOIN book book ON book.author_id = me.id
- author me JOIN book book ON bar.author_id = me.id
+For multi-column foreign keys, you will need to specify a C<foreign>-to-C<self>
+mapping for each column in the key. For example, if you're creating a
+relationship from C<Book> to C<Edition>, where the C<Edition> table refers to a
+publisher and a type (e.g. "paperback"):
-You can specify as many foreign => self mappings as necessary. Each key/value
-pair provided in a hashref will be used as ANDed conditions, to add an ORed
-condition, use an arrayref of hashrefs. See the L<SQL::Abstract> documentation
-for more details.
+ {
+ 'foreign.publisher_id' => 'self.publisher_id',
+ 'foreign.type_id' => 'self.type_id',
+ }
+
+This will result in the C<JOIN> clause:
+
+ book me JOIN edition edition ON edition.publisher_id = me.publisher_id
+ AND edition.type_id = me.type_id
+
+Each key-value pair provided in a hashref will be used as C<AND>ed conditions.
+To add an C<OR>ed condition, use an arrayref of hashrefs. See the
+L<SQL::Abstract> documentation for more details.
Valid attributes are as follows:
An arrayref containing a list of accessors in the foreign class to create in
the main class. If, for example, you do the following:
- MyDB::Schema::CD->might_have(liner_notes => 'MyDB::Schema::LinerNotes', undef, {
- proxy => [ qw/notes/ ],
- });
+ MyDB::Schema::CD->might_have(liner_notes => 'MyDB::Schema::LinerNotes',
+ undef, {
+ proxy => [ qw/notes/ ],
+ });
Then, assuming MyDB::Schema::LinerNotes has an accessor named notes, you can do:
=head2 register_relationship
-=head3 Arguments: ($relname, $rel_info)
+=over 4
+
+=item Arguments: $relname, $rel_info
+
+=back
Registers a relationship on the class. This is called internally by
-L<DBIx::Class::ResultSourceProxy> to set up Accessors and Proxies.
+DBIx::Class::ResultSourceProxy to set up Accessors and Proxies.
=cut
sub register_relationship { }
-=head2 related_resultset($name)
+=head2 related_resultset
+
+=over 4
+
+=item Arguments: $relationship_name
+
+=item Return Value: $related_resultset
+
+=back
- $rs = $obj->related_resultset('related_table');
+ $rs = $cd->related_resultset('artist');
-Returns a L<DBIx::Class::ResultSet> for the relationship named $name.
+Returns a L<DBIx::Class::ResultSet> for the relationship named
+$relationship_name.
=cut
Returns the count of all the items in the related resultset, restricted by the
current item or where conditions. Can be called on a
-L<DBIx::Classl::Manual::Glossary/"ResultSet"> or a
+L<DBIx::Class::Manual::Glossary/"ResultSet"> or a
L<DBIx::Class::Manual::Glossary/"Row"> object.
=cut
my $new_obj = $obj->new_related('relname', \%col_data);
Create a new item of the related foreign class. If called on a
-L<DBIx::Class::Manual::Glossary/"Row"> object, it will magically
-set any primary key values into foreign key columns for you. The newly
-created item will not be saved into your storage until you call C<insert>
+L<DBIx::Class::Manual::Glossary/"Row"> object, it will magically set any
+primary key values into foreign key columns for you. The newly created item
+will not be saved into your storage until you call L<DBIx::Class::Row/insert>
on it.
=cut
my $found_item = $obj->find_related('relname', @pri_vals | \%pri_vals);
Attempt to find a related object using its primary key or unique constraints.
-See C<find> in L<DBIx::Class::ResultSet> for details.
+See L<DBIx::Class::ResultSet/find> for details.
=cut
my $new_obj = $obj->find_or_create_related('relname', \%col_data);
-Find or create an item of a related class. See C<find_or_create> in
-L<DBIx::Class::ResultSet> for details.
+Find or create an item of a related class. See
+L<DBIx::Class::ResultSet/"find_or_create"> for details.
=cut
sub find_or_create_related {
my $self = shift;
- return $self->find_related(@_) || $self->create_related(@_);
+ my $obj = $self->find_related(@_);
+ return (defined($obj) ? $obj : $self->create_related(@_));
}
=head2 set_from_related
example, to set the correct author for a book, find the Author object, then
call set_from_related on the book.
-The columns are only set in the local copy of the object, call C<update> to set
-them in the storage.
+The columns are only set in the local copy of the object, call L</update> to
+set them in the storage.
=cut
"condition for $rel is of type ".
(ref $cond ? ref $cond : 'plain scalar')
) unless ref $cond eq 'HASH';
- my $f_class = $self->result_source->schema->class($rel_obj->{class});
- $self->throw_exception( "Object $f_obj isn't a ".$f_class )
- unless $f_obj->isa($f_class);
+ if (defined $f_obj) {
+ my $f_class = $self->result_source->schema->class($rel_obj->{class});
+ $self->throw_exception( "Object $f_obj isn't a ".$f_class )
+ unless $f_obj->isa($f_class);
+ }
$self->set_columns(
$self->result_source->resolve_condition(
$rel_obj->{cond}, $f_obj, $rel));
$book->update_from_related('author', $author_obj);
-As C<set_from_related>, but the changes are immediately updated onto your
-storage.
+The same as L</"set_from_related">, but the changes are immediately updated
+in storage.
=cut