use strict;
use warnings;
-use base qw/Class::Data::Inheritable/;
+use base qw/DBIx::Class/;
+
+__PACKAGE__->load_own_components(qw/
+ Helpers
+ Accessor
+ CascadeActions
+ ProxyMethods
+ Base
+/);
__PACKAGE__->mk_classdata('_relationships', { } );
+sub relationships
+{
+ my $self = shift;
+
+ return keys %{$self->_relationships};
+}
+
+sub relationship_info
+{
+ my $self = shift;
+ my ($rel) = @_;
+
+ return $self->_relationships->{$rel};
+}
+
=head1 NAME
DBIx::Class::Relationship - Inter-table relationships
=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.
+model. It allows you to set up relationships and perform joins on them.
+
+Only the helper methods for setting up standard relationship types
+are documented here. For the basic, lower-level methods, see
+L<DBIx::Class::Relationship::Base>.
=head1 METHODS
-=over 4
+All helper methods take the following arguments:
-=cut
+ __PACKAGE__>$method_name('relname', 'Foreign::Class', $cond, $attrs);
+
+Both C<$cond> and C<$attrs> are optional. Pass C<undef> for C<$cond> if
+you want to use the default value for it, but still want to set C<$attrs>.
+See L<DBIx::Class::Relationship::Base> for a list of valid attributes.
-sub add_relationship {
- my ($class, $rel, $f_class, $cond, $attrs) = @_;
- die "Can't create relationship without join condition" unless $cond;
- $attrs ||= {};
- eval "use $f_class;";
- my %rels = %{ $class->_relationships };
- $rels{$rel} = { class => $f_class,
- cond => $cond,
- attrs => $attrs };
- $class->_relationships(\%rels);
- #warn %{$f_class->_columns};
-
- return unless eval { %{$f_class->_columns}; }; # Foreign class not loaded
- my %join = (%$attrs, _action => 'join',
- _aliases => { 'self' => 'me', 'foreign' => $rel },
- _classes => { 'me' => $class, $rel => $f_class });
- eval { $class->_cond_resolve($cond, \%join) };
-
- if ($@) { # If the resolve failed, back out and re-throw the error
- delete $rels{$rel}; #
- $class->_relationships(\%rels);
- $class->throw("Error creating relationship $rel: $@");
- }
- 1;
-}
+=head2 belongs_to
-sub _cond_key {
- my ($self, $attrs, $key) = @_;
- my $action = $attrs->{_action} || '';
- if ($action eq 'convert') {
- unless ($key =~ s/^foreign\.//) {
- $self->throw("Unable to convert relationship to WHERE clause: invalid key ${key}");
- }
- return $key;
- } elsif ($action eq 'join') {
- my ($type, $field) = split(/\./, $key);
- if (my $alias = $attrs->{_aliases}{$type}) {
- my $class = $attrs->{_classes}{$alias};
- $self->throw("Unknown column $field on $class as $alias")
- unless exists $class->_columns->{$field};
- return join('.', $alias, $field);
- } else {
- $self->throw( "Unable to resolve type ${type}: only have aliases for ".
- join(', ', keys %{$attrs->{_aliases} || {}}) );
- }
- }
- return $self->NEXT::ACTUAL::_cond_key($attrs, $key);
-}
+ # in a Bar class (where Foo has many Bars)
+ __PACKAGE__->belongs_to(foo => Foo);
+ my $f_obj = $obj->foo;
+ $obj->foo($new_f_obj);
-sub _cond_value {
- my ($self, $attrs, $key, $value) = @_;
- my $action = $attrs->{_action} || '';
- if ($action eq 'convert') {
- unless ($value =~ s/^self\.//) {
- $self->throw( "Unable to convert relationship to WHERE clause: invalid value ${value}" );
- }
- unless ($self->_columns->{$value}) {
- $self->throw( "Unable to convert relationship to WHERE clause: no such accessor ${value}" );
- }
- push(@{$attrs->{bind}}, $self->get_column($value));
- return '?';
- } elsif ($action eq 'join') {
- my ($type, $field) = split(/\./, $value);
- if (my $alias = $attrs->{_aliases}{$type}) {
- my $class = $attrs->{_classes}{$alias};
- $self->throw("Unknown column $field on $class as $alias")
- unless exists $class->_columns->{$field};
- return join('.', $alias, $field);
- } else {
- $self->throw( "Unable to resolve type ${type}: only have aliases for ".
- join(', ', keys %{$attrs->{_aliases} || {}}) );
- }
- }
-
- return $self->NEXT::ACTUAL::_cond_value($attrs, $key, $value)
-}
+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
+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
+the column name.
-sub search_related {
- my $self = shift;
- return $self->_literal_related('search', @_);
-}
+NOTE: If you are used to L<Class::DBI> relationships, this is the equivalent
+of C<has_a>.
-sub count_related {
- my $self = shift;
- return $self->_literal_related('count', @_);
-}
+=head2 has_many
-sub _literal_related {
- my $self = shift;
- my $op = shift;
- my $meth = "${op}_literal";
- my $rel = shift;
- my $attrs = { };
- if (@_ > 1 && ref $_[$#_] eq 'HASH') {
- $attrs = { %{ pop(@_) } };
- }
- my $rel_obj = $self->_relationships->{$rel};
- $self->throw( "No such relationship ${rel}" ) unless $rel_obj;
- $attrs = { %{$rel_obj->{attrs} || {}}, %{$attrs || {}} };
- my $s_cond;
- if (@_) {
- $self->throw( "Invalid query: @_" ) if (@_ > 1 && (@_ % 2 == 1));
- my $query = ((@_ > 1) ? {@_} : shift);
- $s_cond = $self->_cond_resolve($query, $attrs);
- }
- $attrs->{_action} = 'convert'; # shouldn't we resolve the cond to something
- # to merge into the AST really?
- my ($cond) = $self->_cond_resolve($rel_obj->{cond}, $attrs);
- $cond = "${s_cond} AND ${cond}" if $s_cond;
- #warn $rel_obj->{class}." $meth $cond ".join(', ', @{$attrs->{bind}});
- return $self->resolve_class($rel_obj->{class}
- )->$meth($cond, @{$attrs->{bind} || []}, $attrs);
-}
+ # in a Foo class (where Foo has many Bars)
+ __PACKAGE__->has_many(bar => Bar, 'foo');
+ my $f_resultset = $obj->foo;
+ my $f_resultset = $obj->foo({ name => { LIKE => '%macaroni%' }, { prefetch => [qw/bar/] });
+ my @f_obj = $obj->foo;
-sub create_related {
- my $class = shift;
- return $class->new_related(@_)->insert;
-}
+ $obj->add_to_foo(\%col_data);
-sub new_related {
- my ($self, $rel, $values, $attrs) = @_;
- $self->throw( "Can't call new_related as class method" )
- unless ref $self;
- $self->throw( "new_related needs a hash" )
- unless (ref $values eq 'HASH');
- my $rel_obj = $self->_relationships->{$rel};
- $self->throw( "No such relationship ${rel}" ) unless $rel_obj;
- $self->throw( "Can't abstract implicit create for ${rel}, condition not a hash" )
- unless ref $rel_obj->{cond} eq 'HASH';
- $attrs = { %{$rel_obj->{attrs}}, %{$attrs || {}}, _action => 'convert' };
- my %fields = %$values;
- while (my ($k, $v) = each %{$rel_obj->{cond}}) {
- $self->_cond_value($attrs, $k => $v);
- $fields{$self->_cond_key($attrs, $k)} = (@{delete $attrs->{bind}})[0];
- }
- return $self->resolve_class($rel_obj->{class})->new(\%fields);
-}
+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.
-sub find_or_create_related {
- my $self = shift;
- return ($self->search_related(@_))[0] || $self->create_related(@_);
-}
+If you delete an object in a class with a C<has_many> relationship, all
+related objects will be deleted as well. However, any database-level
+cascade or restrict will take precedence.
-sub set_from_related {
- my ($self, $rel, $f_obj) = @_;
- my $rel_obj = $self->_relationships->{$rel};
- $self->throw( "No such relationship ${rel}" ) unless $rel_obj;
- my $cond = $rel_obj->{cond};
- $self->throw( "set_from_related can only handle a hash condition; the "
- ."condition for $rel is of type ".(ref $cond ? ref $cond : 'plain scalar'))
- unless ref $cond eq 'HASH';
- my $f_class = $self->resolve_class($rel_obj->{class});
- $self->throw( "Object $f_obj isn't a ".$f_class )
- unless $f_obj->isa($f_class);
- foreach my $key (keys %$cond) {
- next if ref $cond->{$key}; # Skip literals and complex conditions
- $self->throw("set_from_related can't handle $key as key")
- unless $key =~ m/^foreign\.([^\.]+)$/;
- my $val = $f_obj->get_column($1);
- $self->throw("set_from_related can't handle ".$cond->{$key}." as value")
- unless $cond->{$key} =~ m/^self\.([^\.]+)$/;
- $self->set_column($1 => $val);
- }
- return 1;
-}
+=head2 might_have
-sub update_from_related {
- my $self = shift;
- $self->set_from_related(@_);
- $self->update;
-}
+ __PACKAGE__->might_have(baz => Baz);
+ my $f_obj = $obj->baz; # to get the baz object
-1;
+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.
+
+If you update or delete an object in a class with a C<might_have> relationship,
+the related object will be updated or deleted as well. Any database-level update
+or delete constraints will override this behavior.
+
+=head2 has_one
-=back
+ __PACKAGE__->has_one(gorch => Gorch);
+ my $f_obj = $obj->gorch;
+
+Creates a one-to-one relationship with another class. This is just like C<might_have>,
+except the implication is that the other object is always present. The only different
+between C<has_one> and C<might_have> is that C<has_one> uses an (ordinary) inner join,
+whereas C<might_have> uses a left join.
+
+
+=head2 many_to_many
+
+ __PACKAGE__->many_to_many( 'accessorname' => 'a_to_b', 'table_b' );
+ my @f_objs = $obj_a->accessorname;
+
+=cut
+
+1;
=head1 AUTHORS
-Matt S. Trout <perl-stuff@trout.me.uk>
+Matt S. Trout <mst@shadowcatsystems.co.uk>
=head1 LICENSE
projects / dbsrgits/DBIx-Class.git / blobdiff