The condition argument describes the C<ON> clause of the C<JOIN>
expression used to connect the two sources when creating SQL queries.
-To create simple equality joins, supply a hashref containing the
-remote table column name as the key(s), and the local table column
-name as the value(s), for example given:
+=head4 Simple equality
+
+To create simple equality joins, supply a hashref containing the remote
+table column name as the key(s) prefixed by C<'foreign.'>, and the
+corresponding local table column name as the value(s) prefixed by C<'self.'>.
+Both C<foreign> and C<self> are pseudo aliases and must be entered
+literally. They will be replaced with the actual correct table alias
+when the SQL is produced.
+
+For example given:
My::Schema::Author->has_many(
books => 'My::Schema::Book',
C<Book> table where the C<Book> table has a column C<author_id>
containing the ID value of the C<Author>.
-C<foreign> and C<self> are pseudo aliases and must be entered
-literally. They will be replaced with the actual correct table alias
-when the SQL is produced.
-
Similarly:
My::Schema::Book->has_many(
This describes the relationship from C<Book> to C<Edition>, where the
C<Edition> table refers to a publisher and a type (e.g. "paperback"):
+=head4 Multiple groups of simple equality conditions
+
As is the default in L<SQL::Abstract>, the key-value pairs will be
-C<AND>ed in the result. C<OR> can be achieved with an arrayref, for
-example a condition like:
+C<AND>ed in the resulting C<JOIN> clause. An C<OR> can be achieved with
+an arrayref. For example a condition like:
My::Schema::Item->has_many(
related_item_links => My::Schema::Item::Links,
C<Item::Links> is a many-to-many linking table, linking items back to
themselves in a peer fashion (without a "parent-child" designation)
+=head4 Custom join conditions
+
+ NOTE: The custom join condition specification mechanism is capable of
+ generating JOIN clauses of virtually unlimited complexity. This may limit
+ your ability to traverse some of the more involved relationship chains the
+ way you expect, *and* may bring your RDBMS to its knees. Exercise care
+ when declaring relationships as described here.
+
To specify joins which describe more than a simple equality of column
values, the custom join condition coderef syntax can be used. For
example:
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<< $row_object->relationship >>, as opposed to
-C<< $rs->related_resultset('relationship') >>. In this case C<$row_object> is
+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_rowobj} >>, so a user can do the
following:
'4', '1990', '1979'
Note that in order to be able to use
-L<< $row->create_related|DBIx::Class::Relationship::Base/create_related >>,
+L<< $result->create_related|DBIx::Class::Relationship::Base/create_related >>,
the coderef must not only return as its second such a "simple" condition
hashref which does not depend on joins being available, but the hashref must
contain only plain values/deflatable objects, such that the result can be
passed directly to L<DBIx::Class::Relationship::Base/set_from_related>. For
instance the C<year> constraint in the above example prevents the relationship
-from being used to to create related objects (an exception will be thrown).
+from being used to create related objects (an exception will be thrown).
In order to allow the user to go truly crazy when generating a custom C<ON>
clause, the C<$args> hashref passed to the subroutine contains some extra
metadata. Currently the supplied coderef is executed as:
$relationship_info->{cond}->({
- self_alias => The alias of the invoking resultset ('me' in case of a row object),
+ self_alias => The alias of the invoking resultset ('me' in case of a result object),
foreign_alias => The alias of the to-be-joined resultset (often matches relname),
self_resultsource => The invocant's resultsource,
foreign_relname => The relationship name (does *not* always match foreign_alias),
- self_rowobj => The invocant itself in case of $row_obj->relationship
+ self_rowobj => The invocant itself in case of a $result_object->$relationship call
});
=head3 attributes
=item proxy =E<gt> $column | \@columns | \%column
+The 'proxy' attribute can be used to retrieve values, and to perform
+updates if the relationship has 'cascade_update' set. The 'might_have'
+and 'has_one' relationships have this set by default; if you want a proxy
+to update across a 'belongs_to' relationship, you must set the attribute
+yourself.
+
=over 4
=item \@columns
$cd->notes('Notes go here'); # set notes -- LinerNotes object is
# created if it doesn't exist
+For a 'belongs_to relationship, note the 'cascade_update':
+
+ MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd,
+ { proxy => ['title'], cascade_update => 1 }
+ );
+ $track->title('New Title');
+ $track->update; # updates title in CD
+
=item \%column
A hashref where each key is the accessor you want installed in the main class,
-and its value is the name of the original in the fireign class.
+and its value is the name of the original in the foreign class.
- MyApp::Schema::Track->belongs_to( cd => 'DBICTest::Schema::CD', 'cd', {
+ MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd', {
proxy => { cd_title => 'title' },
});
-This will create an accessor named C<cd_title> on the C<$track> row object.
+This will create an accessor named C<cd_title> on the C<$track> result object.
=back
NOTE: you can pass a nested struct too, for example:
- MyApp::Schema::Track->belongs_to( cd => 'DBICTest::Schema::CD', 'cd', {
+ MyApp::Schema::Track->belongs_to( cd => 'MyApp::Schema::CD', 'cd', {
proxy => [ 'year', { cd_title => 'title' } ],
});
per-relationship basis by supplying C<< cascade_update => 0 >> in
the relationship 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 >>.
+
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
have update called. It will not change foreign keys automatically -
=over 4
-=item Arguments: $relname, $rel_info
+=item Arguments: $rel_name, $rel_info
=back
=over 4
-=item Arguments: $relationship_name
+=item Arguments: $rel_name
-=item Return Value: $related_resultset
+=item Return Value: L<$related_resultset|DBIx::Class::ResultSet>
=back
$rs = $cd->related_resultset('artist');
Returns a L<DBIx::Class::ResultSet> for the relationship named
-$relationship_name.
+$rel_name.
+
+=head2 $relationship_accessor
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | L<$related_resultset|DBIx::Class::ResultSet> | undef
+
+=back
+
+ # These pairs do the same thing
+ $result = $cd->related_resultset('artist')->single; # has_one relationship
+ $result = $cd->artist;
+ $rs = $cd->related_resultset('tracks'); # has_many relationship
+ $rs = $cd->tracks;
+
+This is the recommended way to traverse through relationships, based
+on the L</accessor> name given in the relationship definition.
+
+This will return either a L<Result|DBIx::Class::Manual::ResultClass> or a
+L<ResultSet|DBIx::Class::ResultSet>, depending on if the relationship is
+C<single> (returns only one row) or C<multi> (returns many rows). The
+method may also return C<undef> if the relationship doesn't exist for
+this instance (like in the case of C<might_have> relationships).
=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_info = $self->relationship_info($rel);
- $self->throw_exception( "No such relationship ${rel}" )
- unless $rel_info;
- return $self->{related_resultsets}{$rel} ||= do {
+ return $self->{related_resultsets}{$rel}
+ if defined $self->{related_resultsets}{$rel};
+
+ return $self->{related_resultsets}{$rel} = do {
+
+ my $rel_info = $self->relationship_info($rel)
+ or $self->throw_exception( "No such relationship '$rel'" );
+
my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
$attrs = { %{$rel_info->{attrs} || {}}, %$attrs };
if (@_ > 1 && (@_ % 2 == 1));
my $query = ((@_ > 1) ? {@_} : shift);
- my $source = $self->result_source;
+ my $rsrc = $self->result_source;
# condition resolution may fail if an incomplete master-object prefetch
# is encountered - that is ok during prefetch construction (not yet in_storage)
my ($cond, $is_crosstable) = try {
- $source->_resolve_condition( $rel_info->{cond}, $rel, $self, $rel )
+ $rsrc->_resolve_condition( $rel_info->{cond}, $rel, $self, $rel )
}
catch {
if ($self->in_storage) {
# keep in mind that the following if() block is part of a do{} - no return()s!!!
if ($is_crosstable) {
$self->throw_exception (
- "A cross-table relationship condition returned for statically declared '$rel'")
- unless ref $rel_info->{cond} eq 'CODE';
+ "A cross-table relationship condition returned for statically declared '$rel'"
+ ) unless ref $rel_info->{cond} eq 'CODE';
# A WHOREIFFIC hack to reinvoke the entire condition resolution
# with the correct alias. Another way of doing this involves a
# root alias as 'me', instead of $rel (as opposed to invoking
# $rs->search_related)
- local $source->{_relationships}{me} = $source->{_relationships}{$rel}; # make the fake 'me' rel
- my $obj_table_alias = lc($source->source_name) . '__row';
+ local $rsrc->{_relationships}{me} = $rsrc->{_relationships}{$rel}; # make the fake 'me' rel
+ my $obj_table_alias = lc($rsrc->source_name) . '__row';
$obj_table_alias =~ s/\W+/_/g;
- $source->resultset->search(
+ $rsrc->resultset->search(
$self->ident_condition($obj_table_alias),
{ alias => $obj_table_alias },
)->search_related('me', $query, $attrs)
# at some point what it does. Also the entire UNRESOLVABLE_CONDITION
# business seems shady - we could simply not query *at all*
if ($cond eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
- my $reverse = $source->reverse_relationship_info($rel);
+ my $reverse = $rsrc->reverse_relationship_info($rel);
foreach my $rev_rel (keys %$reverse) {
if ($reverse->{$rev_rel}{attrs}{accessor} && $reverse->{$rev_rel}{attrs}{accessor} eq 'multi') {
weaken($attrs->{related_objects}{$rev_rel}[0] = $self);
}
$query = ($query ? { '-and' => [ $cond, $query ] } : $cond);
- $self->result_source->related_source($rel)->resultset->search(
+ $rsrc->related_source($rel)->resultset->search(
$query, $attrs
);
}
=head2 search_related
- @objects = $rs->search_related('relname', $cond, $attrs);
- $objects_rs = $rs->search_related('relname', $cond, $attrs);
+=over 4
+
+=item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
+
+=item Return Value: L<$resultset|DBIx::Class::ResultSet> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
+
+=back
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.
+results represented by the L<DBIx::Class::ResultSet> it was called
+upon.
+
+See L<DBIx::Class::ResultSet/search_related> for more information.
=cut
=head2 search_related_rs
- ( $objects_rs ) = $rs->search_related_rs('relname', $cond, $attrs);
-
This method works exactly the same as search_related, except that
it guarantees a resultset, even in list context.
=head2 count_related
- $obj->count_related('relname', $cond, $attrs);
+=over 4
+
+=item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
+
+=item Return Value: $count
+
+=back
-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::Class::Manual::Glossary/"ResultSet"> or a
-L<DBIx::Class::Manual::Glossary/"Row"> object.
+Returns the count of all the rows in the related resultset, restricted by the
+current result or where conditions.
=cut
sub count_related {
- my $self = shift;
- return $self->search_related(@_)->count;
+ shift->search_related(@_)->count;
}
=head2 new_related
- my $new_obj = $obj->new_related('relname', \%col_data);
+=over 4
+
+=item Arguments: $rel_name, \%col_data
-Create a new item of the related foreign class. If called on a
-L<Row|DBIx::Class::Manual::Glossary/"Row"> object, it will magically
-set any foreign key columns of the new object to the related primary
-key columns of the source object for you. The newly created item will
-not be saved into your storage until you call L<DBIx::Class::Row/insert>
-on it.
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
+
+=back
+
+Create a new result object of the related foreign class. It will magically set
+any foreign key columns of the new object to the related primary key columns
+of the source object for you. The newly created result will not be saved into
+your storage until you call L<DBIx::Class::Row/insert> on it.
=cut
sub new_related {
- my ($self, $rel, $values, $attrs) = @_;
+ my ($self, $rel, $values) = @_;
# FIXME - this is a bad position for this (also an identical copy in
# set_from_related), but I have no saner way to hook, and I absolutely
if (ref $self) { # cdbi calls this as a class method, /me vomits
my $rsrc = $self->result_source;
- my (undef, $crosstable, $relcols) = $rsrc->_resolve_condition (
- $rsrc->relationship_info($rel)->{cond}, $rel, $self, $rel
+ my $rel_info = $rsrc->relationship_info($rel)
+ or $self->throw_exception( "No such relationship '$rel'" );
+ my (undef, $crosstable, $cond_targets) = $rsrc->_resolve_condition (
+ $rel_info->{cond}, $rel, $self, $rel
);
$self->throw_exception("Custom relationship '$rel' does not resolve to a join-free condition fragment")
if $crosstable;
- if (@{$relcols || []} and @$relcols = grep { ! exists $values->{$_} } @$relcols) {
+ if (my @unspecified_rel_condition_chunks = grep { ! exists $values->{$_} } @{$cond_targets||[]} ) {
$self->throw_exception(sprintf (
"Custom relationship '%s' not definitive - returns conditions instead of values for column(s): %s",
$rel,
- map { "'$_'" } @$relcols
+ map { "'$_'" } @unspecified_rel_condition_chunks
));
}
}
- my $row = $self->search_related($rel)->new($values, $attrs);
- return $row;
+ return $self->search_related($rel)->new_result($values);
}
=head2 create_related
- my $new_obj = $obj->create_related('relname', \%col_data);
+=over 4
+
+=item Arguments: $rel_name, \%col_data
+
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
+
+=back
-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.
+ my $result = $obj->create_related($rel_name, \%col_data);
+
+Creates a new result object, similarly to new_related, and also inserts the
+result's data into your storage medium. See the distinction between C<create>
+and C<new> in L<DBIx::Class::ResultSet> for details.
=cut
=head2 find_related
- my $found_item = $obj->find_related('relname', @pri_vals | \%pri_vals);
+=over 4
+
+=item Arguments: $rel_name, \%col_data | @pk_values, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
+
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
+
+=back
+
+ my $result = $obj->find_related($rel_name, \%col_data);
Attempt to find a related object using its primary key or unique constraints.
See L<DBIx::Class::ResultSet/find> for details.
=cut
sub find_related {
- my $self = shift;
- my $rel = shift;
- return $self->search_related($rel)->find(@_);
+ #my ($self, $rel, @args) = @_;
+ return shift->search_related(shift)->find(@_);
}
=head2 find_or_new_related
- my $new_obj = $obj->find_or_new_related('relname', \%col_data);
+=over 4
+
+=item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
-Find an item of a related class. If none exists, instantiate a new item of the
-related class. The object will not be saved into your storage until you call
-L<DBIx::Class::Row/insert> on it.
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
+
+=back
+
+Find a result object of a related class. See L<DBIx::Class::ResultSet/find_or_new>
+for details.
=cut
=head2 find_or_create_related
- my $new_obj = $obj->find_or_create_related('relname', \%col_data);
+=over 4
-Find or create an item of a related class. See
+=item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
+
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
+
+=back
+
+Find or create a result object of a related class. See
L<DBIx::Class::ResultSet/find_or_create> for details.
=cut
=head2 update_or_create_related
- my $updated_item = $obj->update_or_create_related('relname', \%col_data, \%attrs?);
+=over 4
+
+=item Arguments: $rel_name, \%col_data, { key => $unique_constraint, L<%attrs|DBIx::Class::ResultSet/ATTRIBUTES> }?
+
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
-Update or create an item of a related class. See
+=back
+
+Update or create a result object of a related class. See
L<DBIx::Class::ResultSet/update_or_create> for details.
=cut
sub update_or_create_related {
- my $self = shift;
- my $rel = shift;
- return $self->related_resultset($rel)->update_or_create(@_);
+ #my ($self, $rel, @args) = @_;
+ shift->related_resultset(shift)->update_or_create(@_);
}
=head2 set_from_related
+=over 4
+
+=item Arguments: $rel_name, L<$result|DBIx::Class::Manual::ResultClass>
+
+=item Return Value: not defined
+
+=back
+
$book->set_from_related('author', $author_obj);
$book->author($author_obj); ## same thing
my $rsrc = $self->result_source;
my $rel_info = $rsrc->relationship_info($rel)
- or $self->throw_exception( "No such relationship ${rel}" );
+ or $self->throw_exception( "No such relationship '$rel'" );
if (defined $f_obj) {
my $f_class = $rel_info->{class};
- $self->throw_exception( "Object $f_obj isn't a ".$f_class )
+ $self->throw_exception( "Object '$f_obj' isn't a ".$f_class )
unless blessed $f_obj and $f_obj->isa($f_class);
}
#
# sanity check - currently throw when a complex coderef rel is encountered
# FIXME - should THROW MOAR!
- my ($cond, $crosstable, $relcols) = $rsrc->_resolve_condition (
+ my ($cond, $crosstable, $cond_targets) = $rsrc->_resolve_condition (
$rel_info->{cond}, $f_obj, $rel, $rel
);
$self->throw_exception("Custom relationship '$rel' does not resolve to a join-free condition fragment")
$self->throw_exception(sprintf (
"Custom relationship '%s' not definitive - returns conditions instead of values for column(s): %s",
$rel,
- map { "'$_'" } @$relcols
- )) if @{$relcols || []};
+ map { "'$_'" } @$cond_targets
+ )) if $cond_targets;
$self->set_columns($cond);
=head2 update_from_related
+=over 4
+
+=item Arguments: $rel_name, L<$result|DBIx::Class::Manual::ResultClass>
+
+=item Return Value: not defined
+
+=back
+
$book->update_from_related('author', $author_obj);
The same as L</"set_from_related">, but the changes are immediately updated
=head2 delete_related
- $obj->delete_related('relname', $cond, $attrs);
+=over 4
+
+=item Arguments: $rel_name, $cond?, L<\%attrs?|DBIx::Class::ResultSet/ATTRIBUTES>
+
+=item Return Value: $underlying_storage_rv
+
+=back
-Delete any related item subject to the given conditions.
+Delete any related row, subject to the given conditions. Internally, this
+calls:
+
+ $self->search_related(@_)->delete
+
+And returns the result of that.
=cut
=head2 add_to_$rel
-B<Currently only available for C<has_many>, C<many-to-many> and 'multi' type
+B<Currently only available for C<has_many>, C<many_to_many> and 'multi' type
relationships.>
+=head3 has_many / multi
+
=over 4
-=item Arguments: ($foreign_vals | $obj), $link_vals?
+=item Arguments: \%col_data
+
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
+
+=back
+
+Creates/inserts a new result object. Internally, this calls:
+
+ $self->create_related($rel, @_)
+
+And returns the result of that.
+
+=head3 many_to_many
+
+=over 4
+
+=item Arguments: (\%col_data | L<$result|DBIx::Class::Manual::ResultClass>), \%link_col_data?
+
+=item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
=back
my $role = $schema->resultset('Role')->find(1);
$actor->add_to_roles($role);
- # creates a My::DBIC::Schema::ActorRoles linking table row object
+ # creates a My::DBIC::Schema::ActorRoles linking table result object
$actor->add_to_roles({ name => 'lead' }, { salary => 15_000_000 });
- # creates a new My::DBIC::Schema::Role row object and the linking table
+ # creates a new My::DBIC::Schema::Role result object and the linking table
# object with an extra column in the link
-Adds a linking table object for C<$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>.
+Adds a linking table object. 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_col_data>.
+
+See L<DBIx::Class::Relationship/many_to_many> for additional details.
=head2 set_$rel
-B<Currently only available for C<many-to-many> relationships.>
+B<Currently only available for C<many_to_many> relationships.>
=over 4
-=item Arguments: (\@hashrefs | \@objs), $link_vals?
+=item Arguments: (\@hashrefs_of_col_data | L<\@result_objs|DBIx::Class::Manual::ResultClass>), $link_vals?
+
+=item Return Value: not defined
=back
=head2 remove_from_$rel
-B<Currently only available for C<many-to-many> relationships.>
+B<Currently only available for C<many_to_many> relationships.>
=over 4
-=item Arguments: $obj
+=item Arguments: L<$result|DBIx::Class::Manual::ResultClass>
+
+=item Return Value: not defined
=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 $role's My::DBIC::Schema::ActorRoles linking table result 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.
-=head1 AUTHORS
+=head1 AUTHOR AND CONTRIBUTORS
-Matt S. Trout <mst@shadowcatsystems.co.uk>
+See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
=head1 LICENSE
projects / dbsrgits/DBIx-Class.git / blobdiff