=head1 DESCRIPTION
-This class handles relationships between the tables in your database
-model. It allows your to set up relationships, and to perform joins
-on searches.
+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>.
=head1 METHODS
=head2 add_relationship
+=head3 Arguments: ('relname', 'Foreign::Class', $cond, $attrs)
+
__PACKAGE__->add_relationship('relname', 'Foreign::Class', $cond, $attrs);
The condition needs to be an SQL::Abstract-style representation of the
-join between the tables. For example, if you're creating a rel from Foo to Bar,
+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>
+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.
+
+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:
- { 'foreign.foo_id' => 'self.id' }
+ { 'foreign.author_id' => 'self.id' }
will result in the JOIN clause
- foo me JOIN bar bar ON bar.foo_id = me.id
+ author me JOIN book book ON bar.author_id = me.id
-You can specify as many foreign => self mappings as necessary.
+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.
Valid attributes are as follows:
=item proxy
-An arrayref containing a list of accessors in the foreign class to proxy in
+An arrayref containing a list of accessors in the foreign class to create in
the main class. If, for example, you do the following:
- __PACKAGE__->might_have(bar => 'Bar', undef, { proxy => [ qw/margle/ ] });
+ MyDB::Schema::CD->might_have(liner_notes => 'MyDB::Schema::LinerNotes', undef, {
+ proxy => [ qw/notes/ ],
+ });
-Then, assuming Bar has an accessor named margle, you can do:
+Then, assuming MyDB::Schema::LinerNotes has an accessor named notes, you can do:
- my $obj = Foo->find(1);
- $obj->margle(10); # set margle; Bar object is created if it doesn't exist
+ my $cd = MyDB::Schema::CD->find(1);
+ $cd->notes('Notes go here'); # set notes -- LinerNotes object is
+ # created if it doesn't exist
=item accessor
=head3 Arguments: ($relname, $rel_info)
-Registers a relationship on the class
+Registers a relationship on the class. This is called internally by
+L<DBIx::Class::ResultSourceProxy> to set up Accessors and Proxies.
=cut
sub register_relationship { }
+=head2 related_resultset($name)
+
+ $rs = $obj->related_resultset('related_table');
+
+Returns a L<DBIx::Class::ResultSet> for the relationship named $name.
+
+=cut
+
+sub related_resultset {
+ my $self = shift;
+ $self->throw_exception("Can't call *_related as class methods") unless ref $self;
+ my $rel = shift;
+ my $rel_obj = $self->relationship_info($rel);
+ $self->throw_exception( "No such relationship ${rel}" ) unless $rel_obj;
+
+ return $self->{related_resultsets}{$rel} ||= do {
+ my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
+ $attrs = { %{$rel_obj->{attrs} || {}}, %$attrs };
+
+ $self->throw_exception( "Invalid query: @_" ) if (@_ > 1 && (@_ % 2 == 1));
+ my $query = ((@_ > 1) ? {@_} : shift);
+
+ my $cond = $self->result_source->resolve_condition($rel_obj->{cond}, $rel, $self);
+ if (ref $cond eq 'ARRAY') {
+ $cond = [ map { my $hash;
+ foreach my $key (keys %$_) {
+ my $newkey = $key =~ /\./ ? "me.$key" : $key;
+ $hash->{$newkey} = $_->{$key};
+ }; $hash } @$cond ];
+ } else {
+ foreach my $key (grep { ! /\./ } keys %$cond) {
+ $cond->{"me.$key"} = delete $cond->{$key};
+ }
+ }
+ $query = ($query ? { '-and' => [ $cond, $query ] } : $cond);
+ $self->result_source->related_source($rel)->resultset->search($query, $attrs);
+ };
+}
+
=head2 search_related
- My::Table->search_related('relname', $cond, $attrs);
+ $rs->search_related('relname', $cond, $attrs);
+
+Run a search on a related resultset. The search will be restricted to the
+item or items represented by the L<DBIx::Class::ResultSet> it was called
+upon. This method can be called on a ResultSet, a Row or a ResultSource class.
=cut
$obj->count_related('relname', $cond, $attrs);
+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/"Row"> object.
+
=cut
sub count_related {
return $self->search_related(@_)->count;
}
+=head2 new_related
+
+ my $new_obj = $obj->new_related('relname', \%col_data);
+
+Create a new item of the related foreign class. If called on a
+L<DBIx::Class::Manual::Glossary/"Row"> object, it will magically
+set any primary key values into foreign key columns for you. The newly
+created item will not be saved into your storage until you call C<insert>
+on it.
+
+=cut
+
+sub new_related {
+ my ($self, $rel, $values, $attrs) = @_;
+ return $self->search_related($rel)->new($values, $attrs);
+}
+
=head2 create_related
- My::Table->create_related('relname', \%col_data);
+ my $new_obj = $obj->create_related('relname', \%col_data);
+
+Creates a new item, similarly to new_related, and also inserts the item's data
+into your storage medium. See the distinction between C<create> and C<new>
+in L<DBIx::Class::ResultSet> for details.
=cut
return $obj;
}
-=head2 new_related
-
- My::Table->new_related('relname', \%col_data);
-
-=cut
-
-sub new_related {
- my ($self, $rel, $values, $attrs) = @_;
- return $self->search_related($rel)->new($values, $attrs);
-}
-
=head2 find_related
- My::Table->find_related('relname', @pri_vals | \%pri_vals);
+ 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.
=cut
=head2 find_or_create_related
- My::Table->find_or_create_related('relname', \%col_data);
+ 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.
=cut
=head2 set_from_related
- My::Table->set_from_related('relname', $rel_obj);
+ $book->set_from_related('author', $author_obj);
+
+Set column values on the current object, using related values from the given
+related object. This is used to associate previously separate objects, for
+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.
=cut
=head2 update_from_related
- My::Table->update_from_related('relname', $rel_obj);
+ $book->update_from_related('author', $author_obj);
+
+As C<set_from_related>, but the changes are immediately updated onto your
+storage.
=cut
=head2 delete_related
- My::Table->delete_related('relname', $cond, $attrs);
+ $obj->delete_related('relname', $cond, $attrs);
+
+Delete any related item subject to the given conditions.
=cut
1;
-=head2 related_resultset($name)
-
-Returns a L<DBIx::Class::ResultSet> for the relationship named $name.
-
- $rs = $obj->related_resultset('related_table');
-
-=cut
-
-sub related_resultset {
- my $self = shift;
- $self->throw_exception("Can't call *_related as class methods") unless ref $self;
- my $rel = shift;
- my $rel_obj = $self->relationship_info($rel);
- $self->throw_exception( "No such relationship ${rel}" ) unless $rel_obj;
-
- return $self->{related_resultsets}{$rel} ||= do {
- my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
- $attrs = { %{$rel_obj->{attrs} || {}}, %$attrs };
-
- $self->throw_exception( "Invalid query: @_" ) if (@_ > 1 && (@_ % 2 == 1));
- my $query = ((@_ > 1) ? {@_} : shift);
-
- my $cond = $self->result_source->resolve_condition($rel_obj->{cond}, $rel, $self);
- if (ref $cond eq 'ARRAY') {
- $cond = [ map { my $hash;
- foreach my $key (keys %$_) {
- my $newkey = $key =~ /\./ ? "me.$key" : $key;
- $hash->{$newkey} = $_->{$key};
- }; $hash } @$cond ];
- } else {
- foreach my $key (grep { ! /\./ } keys %$cond) {
- $cond->{"me.$key"} = delete $cond->{$key};
- }
- }
- $query = ($query ? { '-and' => [ $cond, $query ] } : $cond);
- $self->result_source->related_source($rel)->resultset->search($query, $attrs);
- };
-}
-
=head1 AUTHORS
Matt S. Trout <mst@shadowcatsystems.co.uk>
projects / dbsrgits/DBIx-Class.git / commitdiff