| Subject: | Grouping JOIN Clauses with Parentheses |
As far as I can tell, it's not possible to group joining, as in the following SQL:
SELECT *
FROM A
LEFT JOIN (D JOIN E ON E.d_id = D.id) ON (D.a_id = A.id);
(Only grab D if it also has E.)
The attached patch piggybacks off relationships' join attributes, allowing one relationship to include another, surrounding them both in parentheses:
package Test::Schema::Result::A;
...
__PACKAGE__->has_many(
"D" => "Test::Schema::Result::D",
{ "foreign.a_id" => "self.id" },
{ join => 'E' },
);
It seems to work for complex joins, as well, but it's only been lightly tested (though it does NOT fail the current test suite).
| Subject: | dbic_join_grouping.patch |
diff -rupN DBIx-Class-0.082820/lib/DBIx/Class/ResultSource.pm DBIx-Class-0.082820.new/lib/DBIx/Class/ResultSource.pm
--- DBIx-Class-0.082820/lib/DBIx/Class/ResultSource.pm 2015-03-20 12:31:00.000000000 -0400
+++ DBIx-Class-0.082820.new/lib/DBIx/Class/ResultSource.pm 2015-05-05 17:40:07.646500380 -0400
@@ -1700,6 +1700,12 @@ sub _resolve_join {
or $self->throw_exception("No such relationship $join on " . $self->source_name);
my $rel_src = $self->related_source($join);
+
+ my @grouped_joins;
+ if ($rel_info->{attrs}{join}){
+ @grouped_joins = $rel_src->_resolve_join($rel_info->{attrs}{join}, $as, $seen, [@$jpath, {$join => $as}]);
+ }
+
return [ { $as => $rel_src->from,
-rsrc => $rel_src,
-join_type => $parent_force_left
@@ -1714,6 +1720,7 @@ sub _resolve_join {
),
-alias => $as,
-relation_chain_depth => ( $seen->{-relation_chain_depth} || 0 ) + 1,
+ @grouped_joins ? (-join => \@grouped_joins) : (),
},
scalar $self->_resolve_condition($rel_info->{cond}, $as, $alias, $join)
];
diff -rupN DBIx-Class-0.082820/lib/DBIx/Class/SQLMaker.pm DBIx-Class-0.082820.new/lib/DBIx/Class/SQLMaker.pm
--- DBIx-Class-0.082820/lib/DBIx/Class/SQLMaker.pm 2015-03-20 07:54:07.000000000 -0400
+++ DBIx-Class-0.082820.new/lib/DBIx/Class/SQLMaker.pm 2015-05-05 17:38:39.899603508 -0400
@@ -402,6 +402,9 @@ sub _gen_from_blocks {
if (ref $to eq 'ARRAY') {
push(@j, '(', $self->_recurse_from(@$to), ')');
}
+ elsif (ref $to eq 'HASH' and $to->{-join}){
+ push(@j, '(', $self->_recurse_from($to, @{$to->{-join}}), ')');
+ }
else {
push(@j, $self->_from_chunk_to_sql($to));
}