X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FRelationship.pm;h=c6720e9a609361b1455d553aea25d25c0ce25763;hb=a918d9014c5fc4684efb8b6c2abb84cf60d9c826;hp=9420ab713c8672967ac89facad8523f8bfba2063;hpb=3bd6e3e0f621c4fe3d7562827a9b86ee5b91cbf2;p=dbsrgits%2FDBIx-Class-Historic.git diff --git a/lib/DBIx/Class/Relationship.pm b/lib/DBIx/Class/Relationship.pm index 9420ab7..c6720e9 100644 --- a/lib/DBIx/Class/Relationship.pm +++ b/lib/DBIx/Class/Relationship.pm @@ -113,20 +113,34 @@ See L for a list of valid attributes. $obj->author($new_author_obj); Creates a relationship where the calling class stores the foreign class's -primary key in one (or more) of its columns. If $cond is a column name +primary key in one (or more) of its columns. If C<$cond> is a column name instead of a join condition hash, that is used as the name of the column -holding the foreign key. If $cond is not given, the relname is used as +holding the foreign key. If C<$cond> is not given, the relname is used as the column name. -Cascading deletes are off per default on a C relationship, to turn -them on, pass C<< cascade_delete => 1 >> in the $attr hashref. +If the relationship is optional - i.e. the column containing the foreign +key can be NULL - then the belongs_to relationship does the right +thing - so in the example above C<$obj-Eauthor> would return C. +However in this case you would probably want to set the C +attribute so that a C is done, which makes complex +resultsets involving C or C operations work correctly. +The modified declaration is shown below: + + # in a Book class (where Author has_many Books) + __PACKAGE__->belongs_to(author => 'My::DBIC::Schema::Author', + 'author', {join_type => 'left'}); + + +Cascading deletes are off by default on a C +relationship. To turn them on, pass C<< cascade_delete => 1 >> +in the $attr hashref. NOTE: If you are used to L relationships, this is the equivalent of C. =head2 has_many - # in an Author class (where Author has many Books) + # in an Author class (where Author has_many Books) My::DBIC::Schema::Author->has_many(books => 'My::DBIC::Schema::Book', 'author'); my $booklist = $obj->books; my $booklist = $obj->books({ @@ -142,21 +156,22 @@ of C. Creates a one-to-many relationship, where the corresponding elements of the foreign class store the calling class's primary key in one (or more) of its columns. You should pass the name of the column in the foreign class as the -$cond argument, or specify a complete join condition. +C<$cond> argument, or specify a complete join condition. Three methods are created when you create a has_many relationship. The first method is the expected accessor method. The second is almost exactly the same as the accessor method but "_rs" is added to the end of the method name. This method works just like the normal accessor, except that it returns a resultset no matter what, even in list context. The third method, named -C<< add_to_ >>, will also be added to your Row items, this allows +C<< add_to_ >>, will also be added to your Row items; this allows you to insert new related items, using the same mechanism as in L. If you delete an object in a class with a C relationship, all -the related objects will be deleted as well. However, any database-level -cascade or restrict will take precedence. To turn this behavior off, pass -C<< cascade_delete => 0 >> in the $attr hashref. +the related objects will be deleted as well. To turn this behaviour off, +pass C<< cascade_delete => 0 >> in the C<$attr> hashref. However, any +database-level cascade or restrict will take precedence over a +DBIx-Class-based cascading delete. =head2 might_have @@ -166,12 +181,13 @@ C<< cascade_delete => 0 >> in the $attr hashref. Creates an optional one-to-one relationship with a class, where the foreign class stores our primary key in one of its columns. Defaults to the primary -key of the foreign class unless $cond specifies a column or join condition. +key of the foreign class unless C<$cond> specifies a column or join condition. If you update or delete an object in a class with a C -relationship, the related object will be updated or deleted as well. -Any database-level update or delete constraints will override this behaviour. -To turn off this behavior, add C<< cascade_delete => 0 >> to the $attr hashref. +relationship, the related object will be updated or deleted as well. To +turn off this behavior, add C<< cascade_delete => 0 >> to the C<$attr> +hashref. Any database-level update or delete constraints will override +this behavior. =head2 has_one @@ -204,7 +220,7 @@ left join. My::DBIC::Schema::Actor->many_to_many( roles => 'actor_roles', 'role' ); -Creates a accessors bridging two relationships; not strictly a relationship in +Creates accessors bridging two relationships; not strictly a relationship in its own right, although the accessor will return a resultset or collection of objects just as a has_many would. @@ -212,62 +228,6 @@ To use many_to_many, existing relationships from the original table to the link table, and from the link table to the end table must already exist, these relation names are then used in the many_to_many call. -=head3 Created accessors - -=head4 $rel - -=over 4 - -=item Arguments: $vals?, $attrs - -=back - - my $role_rs = $actor->roles; - - my $role1 = $actor->roles({ name => 'role1' })->first; - -Returns a resultset for the foreign table on the right side of the -many-to-many relationship. (e.g., in the above example, a CD's -producers). Takes the same arguments as L. - -=head4 add_to_$rel - -=over 4 - -=item Arguments: ($foreign_vals | $obj), $link_vals? - -=back - - my $role = $schema->resultset('Role')->find(1); - $actor->add_to_roles($role); - # creates a My::DBIC::Schema::ActorRoles linking table row object - - $actor->add_to_roles({ name => 'lead' }, { salary => 15_000_000 }); - # creates a new My::DBIC::Schema::Role row object and the linking table - # object with an extra column in the link - -Adds a linking table object for C<$obj> or C<$foreign_vals>. If the first -argument is a hash reference, the related object is created first with the -column values in the hash. If an object reference is given, just the linking -table object is created. In either case, any additional column values for the -linking table object can be specified in C<$link_vals>. - -=head4 remove_from_$rel - -=over 4 - -=item Arguments: $obj - -=back - - my $role = $schema->resultset('Role')->find(1); - $actor->remove_from_roles($role); - # removes $role's My::DBIC::Schema::ActorRoles linking table row object - -Removes the link between the current object and the related object. Note that -the related object itself won't be deleted unless you call ->delete() on -it. This method just removes the link between the two objects. - =cut 1;