package DBIx::Class::Relationship::BelongsTo;
use strict;
use warnings;
sub belongs_to {
my ($class, $rel, $f_class, $cond, $attrs) = @_;
eval "require $f_class";
if ($@) {
$class->throw_exception($@) unless $@ =~ /Can't locate/;
}
# no join condition or just a column name
if (!ref $cond) {
my %f_primaries = map { $_ => 1 } eval { $f_class->primary_columns };
$class->throw_exception("Can't infer join condition for ${rel} on ${class}; unable to load ${f_class}")
if $@;
my ($pri, $too_many) = keys %f_primaries;
$class->throw_exception("Can't infer join condition for ${rel} on ${class}; ${f_class} has no primary keys")
unless defined $pri;
$class->throw_exception("Can't infer join condition for ${rel} on ${class}; ${f_class} has multiple primary keys")
if $too_many;
my $fk = defined $cond ? $cond : $rel;
$class->throw_exception("Can't infer join condition for ${rel} on ${class}; $fk is not a column")
unless $class->has_column($fk);
my $acc_type = $class->has_column($rel) ? 'filter' : 'single';
$class->add_relationship($rel, $f_class,
{ "foreign.${pri}" => "self.${fk}" },
{ accessor => $acc_type, %{$attrs || {}} }
);
}
# explicit join condition
elsif (ref $cond eq 'HASH') {
my $cond_rel;
for (keys %$cond) {
if (m/\./) { # Explicit join condition
$cond_rel = $cond;
last;
}
$cond_rel->{"foreign.$_"} = "self.".$cond->{$_};
}
my $acc_type = (keys %$cond_rel == 1 and $class->has_column($rel)) ? 'filter' : 'single';
$class->add_relationship($rel, $f_class,
$cond_rel,
{ accessor => $acc_type, %{$attrs || {}} }
);
}
else {
$class->throw_exception('third argument for belongs_to must be undef, a column name, or a join condition');
}
return 1;
}
=head1 AUTHORS
Alexander Hartmaier <Alexander.Hartmaier@t-systems.at>
Matt S. Trout <mst@shadowcatsystems.co.uk>
=cut
1;