Better linking in Relatiomship POD
[dbsrgits/DBIx-Class-Historic.git] / lib / DBIx / Class / Relationship / BelongsTo.pm
CommitLineData
9b83fccd 1package # hide from PAUSE
2 DBIx::Class::Relationship::BelongsTo;
3
4# Documentation for these methods can be found in
5# DBIx::Class::Relationship
07037f89 6
7use strict;
8use warnings;
9
10sub belongs_to {
11 my ($class, $rel, $f_class, $cond, $attrs) = @_;
aeb1bf75 12 # no join condition or just a column name
7b601771 13 if (!ref $cond) {
fd4df975 14 $class->ensure_class_loaded($f_class);
aeb1bf75 15 my %f_primaries = map { $_ => 1 } eval { $f_class->primary_columns };
fd4df975 16 $class->throw_exception(
17 "Can't infer join condition for ${rel} on ${class}; ".
18 "unable to load ${f_class}: $@"
19 ) if $@;
1e3bc087 20
21 my ($pri, $too_many) = keys %f_primaries;
fd4df975 22 $class->throw_exception(
23 "Can't infer join condition for ${rel} on ${class}; ".
24 "${f_class} has no primary keys"
25 ) unless defined $pri;
26 $class->throw_exception(
27 "Can't infer join condition for ${rel} on ${class}; ".
28 "${f_class} has multiple primary keys"
29 ) if $too_many;
1e3bc087 30
31 my $fk = defined $cond ? $cond : $rel;
fd4df975 32 $class->throw_exception(
33 "Can't infer join condition for ${rel} on ${class}; ".
34 "$fk is not a column of $class"
35 ) unless $class->has_column($fk);
1e3bc087 36
37 my $acc_type = $class->has_column($rel) ? 'filter' : 'single';
07037f89 38 $class->add_relationship($rel, $f_class,
1e3bc087 39 { "foreign.${pri}" => "self.${fk}" },
5a3c5f64 40 { accessor => $acc_type, %{$attrs || {}} }
07037f89 41 );
42 }
aeb1bf75 43 # explicit join condition
4ff1b819 44 elsif (ref $cond) {
45 if (ref $cond eq 'HASH') { # ARRAY is also valid
46 my $cond_rel;
47 for (keys %$cond) {
48 if (m/\./) { # Explicit join condition
49 $cond_rel = $cond;
50 last;
51 }
52 $cond_rel->{"foreign.$_"} = "self.".$cond->{$_};
99be059e 53 }
4ff1b819 54 $cond = $cond_rel;
07037f89 55 }
4ff1b819 56 my $acc_type = ((ref $cond eq 'HASH')
57 && keys %$cond == 1
58 && $class->has_column($rel))
59 ? 'filter'
60 : 'single';
07037f89 61 $class->add_relationship($rel, $f_class,
4ff1b819 62 $cond,
0cc03829 63 { accessor => $acc_type, %{$attrs || {}} }
07037f89 64 );
65 }
7b601771 66 else {
fd4df975 67 $class->throw_exception(
68 'third argument for belongs_to must be undef, a column name, '.
69 'or a join condition'
70 );
7b601771 71 }
07037f89 72 return 1;
73}
74
503536d5 75=head1 AUTHORS
76
77Alexander Hartmaier <Alexander.Hartmaier@t-systems.at>
78
79Matt S. Trout <mst@shadowcatsystems.co.uk>
80
81=cut
82
07037f89 831;