$rows = $self->get_cache;
}
+ # reset the selector list
+ if (List::Util::first { exists $attrs->{$_} } qw{columns select as}) {
+ delete @{$our_attrs}{qw{select as columns +select +as +columns include_columns}};
+ }
+
my $new_attrs = { %{$our_attrs}, %{$attrs} };
# merge new attrs into inherited
- foreach my $key (qw/join prefetch +select +as bind/) {
+ foreach my $key (qw/join prefetch +select +as +columns include_columns bind/) {
next unless exists $attrs->{$key};
$new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
}
- if (List::Util::first { exists $new_attrs->{$_} } qw{select as}) {
- delete $new_attrs->{$_} for (qw{+select +as});
- }
-
- if (exists $new_attrs->{columns}) {
- delete $new_attrs->{'+columns'};
- }
-
my $cond = (@_
? (
(@_ == 1 || ref $_[0] eq "HASH")
# extra selectors do not go in the subquery and there is no point of ordering it
delete $sub_attrs->{$_} for qw/collapse select _prefetch_select as order_by/;
- # if we prefetch, we group_by primary keys only as this is what we would get out
- # of the rs via ->next/->all. We DO WANT to clobber old group_by regardless
- if ( keys %{$attrs->{collapse}} ) {
+ # if we multi-prefetch we group_by primary keys only as this is what we would
+ # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
+ if ( keys %{$attrs->{collapse}} ) {
$sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } ($rsrc->primary_columns) ]
}
$sub_attrs->{select} = $rsrc->storage->_subq_count_select ($rsrc, $sub_attrs);
# this is so that the query can be simplified e.g.
- # * non-limiting joins can be pruned
# * ordering can be thrown away in things like Top limit
$sub_attrs->{-for_count_only} = 1;
return ($self->{attrs} || {})->{alias} || 'me';
}
+=head2 as_subselect_rs
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $resultset
+
+=back
+
+Act as a barrier to SQL symbols. The resultset provided will be made into a
+"virtual view" by including it as a subquery within the from clause. From this
+point on, any joined tables are inaccessible to ->search on the resultset (as if
+it were simply where-filtered without joins). For example:
+
+ my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
+
+ # 'x' now pollutes the query namespace
+
+ # So the following works as expected
+ my $ok_rs = $rs->search({'x.other' => 1});
+
+ # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
+ # def) we look for one row with contradictory terms and join in another table
+ # (aliased 'x_2') which we never use
+ my $broken_rs = $rs->search({'x.name' => 'def'});
+
+ my $rs2 = $rs->as_subselect_rs;
+
+ # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
+ my $not_joined_rs = $rs2->search({'x.other' => 1});
+
+ # works as expected: finds a 'table' row related to two x rows (abc and def)
+ my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
+
+Another example of when one might use this would be to select a subset of
+columns in a group by clause:
+
+ my $rs = $schema->resultset('Bar')->search(undef, {
+ group_by => [qw{ id foo_id baz_id }],
+ })->as_subselect_rs->search(undef, {
+ columns => [qw{ id foo_id }]
+ });
+
+In the above example normally columns would have to be equal to the group by,
+but because we isolated the group by into a subselect the above works.
+
+=cut
+
+sub as_subselect_rs {
+ my $self = shift;
+
+ return $self->result_source->resultset->search( undef, {
+ alias => $self->current_source_alias,
+ from => [{
+ $self->current_source_alias => $self->as_query,
+ -alias => $self->current_source_alias,
+ -source_handle => $self->result_source->handle,
+ }]
+ });
+}
+
# This code is called by search_related, and makes sure there
# is clear separation between the joins before, during, and
# after the relationship. This information is needed later
# we consider the last one thus reverse
for my $j (reverse @requested_joins) {
- if ($rel eq $j->[0]{-join_path}[-1]) {
+ my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
+ if ($rel eq $last_j) {
$j->[0]{-relation_chain_depth}++;
$already_joined++;
last;
}
}
-# alternative way to scan the entire chain - not backwards compatible
-# for my $j (reverse @$from) {
-# next unless ref $j eq 'ARRAY';
-# if ($j->[0]{-join_path} && $j->[0]{-join_path}[-1] eq $rel) {
-# $j->[0]{-relation_chain_depth}++;
-# $already_joined++;
-# last;
-# }
-# }
unless ($already_joined) {
push @$from, $source->_resolve_join(
my %already_grouped = map { $_ => 1 } (@{$attrs->{group_by}});
my $storage = $self->result_source->schema->storage;
+
my $rs_column_list = $storage->_resolve_column_info ($attrs->{from});
- my @chunks = $storage->sql_maker->_order_by_chunks ($attrs->{order_by});
- for my $chunk (map { ref $_ ? @$_ : $_ } (@chunks) ) {
- $chunk =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
+ for my $chunk ($storage->_parse_order_by($attrs->{order_by})) {
if ($rs_column_list->{$chunk} && not $already_grouped{$chunk}++) {
push @{$attrs->{group_by}}, $chunk;
}
my $prefetch_ordering = [];
- my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
+ # this is a separate structure (we don't look in {from} directly)
+ # as the resolver needs to shift things off the lists to work
+ # properly (identical-prefetches on different branches)
+ my $join_map = {};
+ if (ref $attrs->{from} eq 'ARRAY') {
+
+ my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
+
+ for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
+ next unless $j->[0]{-alias};
+ next unless $j->[0]{-join_path};
+ next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
+
+ my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
+
+ my $p = $join_map;
+ $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
+ push @{$p->{-join_aliases} }, $j->[0]{-alias};
+ }
+ }
my @prefetch =
$source->_resolve_prefetch( $prefetch, $alias, $join_map, $prefetch_ordering, $attrs->{collapse} );
return $self->{_attrs} = $attrs;
}
-sub _joinpath_aliases {
- my ($self, $fromspec, $seen) = @_;
-
- my $paths = {};
- return $paths unless ref $fromspec eq 'ARRAY';
-
- my $cur_depth = $seen->{-relation_chain_depth} || 0;
-
- if ($cur_depth % 2) {
- $self->throw_exception ("-relation_chain_depth is not even, something went horribly wrong ($cur_depth)");
- }
-
- for my $j (@$fromspec) {
-
- next if ref $j ne 'ARRAY';
- next if ($j->[0]{-relation_chain_depth} || 0) < $cur_depth;
-
- my $jpath = $j->[0]{-join_path};
-
- my $p = $paths;
- $p = $p->{$_} ||= {} for @{$jpath}[$cur_depth/2 .. $#$jpath]; #only even depths are actual jpath boundaries
- push @{$p->{-join_aliases} }, $j->[0]{-alias};
- }
-
- return $paths;
-}
-
sub _rollout_attr {
my ($self, $attr) = @_;
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