clause of the C<JOIN> statement associated with this relationship.
While every coderef-based condition must return a valid C<ON> clause, it may
-elect to additionally return a simplified join-free condition hashref when
-invoked as C<< $result->relationship >>, as opposed to
-C<< $rs->related_resultset('relationship') >>. In this case C<$result> is
-passed to the coderef as C<< $args->{self_resultobj} >>, so a user can do the
-following:
+elect to additionally return a simplified B<optional> join-free condition
+consisting of a hashref with B<all keys being fully qualified names of columns
+declared on the corresponding result source>. This boils down to two scenarios:
+
+=over
+
+=item *
+
+When relationship resolution is invoked after C<< $result->$rel_name >>, as
+opposed to C<< $rs->related_resultset($rel_name) >>, the C<$result> object
+is passed to the coderef as C<< $args->{self_result_object} >>.
+
+=item *
+
+Alternatively when the user-space invokes resolution via
+C<< $result->set_from_related( $rel_name => $foreign_values_or_object ) >>, the
+corresponding data is passed to the coderef as C<< $args->{foreign_values} >>,
+B<always> in the form of a hashref. If a foreign result object is supplied
+(which is valid usage of L</set_from_related>), its values will be extracted
+into hashref form by calling L<get_columns|DBIx::Class::Row/get_columns>.
+
+=back
+
+Note that the above scenarios are mutually exclusive, that is you will be supplied
+none or only one of C<self_result_object> and C<foreign_values>. In other words if
+you define your condition coderef as:
sub {
my $args = shift;
"$args->{foreign_alias}.artist" => { -ident => "$args->{self_alias}.artistid" },
"$args->{foreign_alias}.year" => { '>', "1979", '<', "1990" },
},
- $args->{self_resultobj} && {
- "$args->{foreign_alias}.artist" => $args->{self_resultobj}->artistid,
+ ! $args->{self_result_object} ? () : {
+ "$args->{foreign_alias}.artist" => $args->{self_result_object}->artistid,
"$args->{foreign_alias}.year" => { '>', "1979", '<', "1990" },
},
+ ! $args->{foreign_values} ? () : {
+ "$args->{self_alias}.artistid" => $args->{foreign_values}{artist},
+ }
);
}
-Now this code:
+Then this code:
my $artist = $schema->resultset("Artist")->find({ id => 4 });
$artist->cds_80s->all;
'4', '1990', '1979'
-Note that in order to be able to use
-L<< $result->create_related|DBIx::Class::Relationship::Base/create_related >>,
-the coderef must not only return as its second such a "simple" condition
-hashref which does not depend on joins being available, but the hashref must
-contain only plain values/deflatable objects, such that the result can be
-passed directly to L<DBIx::Class::Relationship::Base/set_from_related>. For
-instance the C<year> constraint in the above example prevents the relationship
-from being used to create related objects (an exception will be thrown).
+While this code:
+
+ my $cd = $schema->resultset("CD")->search({ artist => 1 }, { rows => 1 })->single;
+ my $artist = $schema->resultset("Artist")->new({});
+ $artist->set_from_related('cds_80s');
+
+Will properly set the C<< $artist->artistid >> field of this new object to C<1>
+
+Note that in order to be able to use L</set_from_related> (and by extension
+L<< $result->create_related|DBIx::Class::Relationship::Base/create_related >>),
+the returned join free condition B<must> contain only plain values/deflatable
+objects. For instance the C<year> constraint in the above example prevents
+the relationship from being used to create related objects using
+C<< $artst->create_related( cds_80s => { title => 'blah' } ) >> (an
+exception will be thrown).
In order to allow the user to go truly crazy when generating a custom C<ON>
clause, the C<$args> hashref passed to the subroutine contains some extra
metadata. Currently the supplied coderef is executed as:
$relationship_info->{cond}->({
- self_resultsource => The resultsource instance on which rel_name is registered
- rel_name => The relationship name (does *NOT* always match foreign_alias)
+ self_resultsource => The resultsource instance on which rel_name is registered
+ rel_name => The relationship name (does *NOT* always match foreign_alias)
- self_alias => The alias of the invoking resultset
- foreign_alias => The alias of the to-be-joined resultset (does *NOT* always match rel_name)
+ self_alias => The alias of the invoking resultset
+ foreign_alias => The alias of the to-be-joined resultset (does *NOT* always match rel_name)
# only one of these (or none at all) will ever be supplied to aid in the
# construction of a join-free condition
- self_resultobj => The invocant object itself in case of a $resultobj->$rel_name() call
- foreign_resultobj => The related object in case of $resultobj->set_from_related($rel_name, $foreign_resultobj)
+
+ self_result_object => The invocant *object* itself in case of a call like
+ $result_object->$rel_name( ... )
+
+ foreign_values => A *hashref* of related data: may be passed in directly or
+ derived via ->get_columns() from a related object in case of
+ $result_object->set_from_related( $rel_name, $foreign_result_object )
# deprecated inconsistent names, will be forever available for legacy code
- self_rowobj => Old deprecated slot for self_resultobj
- foreign_relname => Old deprecated slot for rel_name
+ self_rowobj => Old deprecated slot for self_result_object
+ foreign_relname => Old deprecated slot for rel_name
});
=head3 attributes
The C<belongs_to> relationship does not update across relationships
by default, so if you have a 'proxy' attribute on a belongs_to and want to
-use 'update' on it, you muse set C<< cascade_update => 1 >>.
+use 'update' on it, you must set C<< cascade_update => 1 >>.
This is not a RDMS style cascade update - it purely means that when
an object has update called on it, all the related objects also
# root alias as 'me', instead of $rel (as opposed to invoking
# $rs->search_related)
- local $rsrc->{_relationships}{me} = $rsrc->{_relationships}{$rel}; # make the fake 'me' rel
+ # make the fake 'me' rel
+ local $rsrc->{_relationships}{me} = {
+ %{ $rsrc->{_relationships}{$rel} },
+ _original_name => $rel,
+ };
+
my $obj_table_alias = lc($rsrc->source_name) . '__row';
$obj_table_alias =~ s/\W+/_/g;
return $self->search_related($rel)->new_result( $self->result_source->_resolve_relationship_condition (
infer_values_based_on => $data,
rel_name => $rel,
- self_resultobj => $self,
+ self_result_object => $self,
foreign_alias => $rel,
self_alias => 'me',
)->{inferred_values} );
This is called internally when you pass existing objects as values to
L<DBIx::Class::ResultSet/create>, or pass an object to a belongs_to accessor.
-The columns are only set in the local copy of the object, call L</update> to
-set them in the storage.
+The columns are only set in the local copy of the object, call
+L<update|DBIx::Class::Row/update> to update them in the storage.
=cut
$self->set_columns( $self->result_source->_resolve_relationship_condition (
infer_values_based_on => {},
rel_name => $rel,
- foreign_resultobj => $f_obj,
+ foreign_values => $f_obj,
foreign_alias => $rel,
self_alias => 'me',
)->{inferred_values} );
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