$self->throw_exception ('has_many prefetch with limit (rows/offset) is not supported on resultsets with a custom from attribute')
if (ref $from ne 'ARRAY');
+
# separate attributes
my $sub_attrs = { %$attrs };
delete $attrs->{$_} for qw/where bind rows offset/;
];
}
- # mangle the head of the {from}
- my $self_ident = shift @$from;
+ # mangle {from}
+ $from = [ @$from ];
+ my $select_root = shift @$from;
+ my @outer_from = @$from;
+ my %inner_joins;
my %join_info = map { $_->[0]{-alias} => $_->[0] } (@$from);
- my (%inner_joins);
+ # in complex search_related chains $alias may *not* be 'me'
+ # so always include it in the inner join, and also shift away
+ # from the outer stack, so that the two datasets actually do
+ # meet
+ if ($select_root->{-alias} ne $alias) {
+ $inner_joins{$alias} = 1;
+
+ while (@outer_from && $outer_from[0][0]{-alias} ne $alias) {
+ shift @outer_from;
+ }
+ if (! @outer_from) {
+ $self->throw_exception ("Unable to find '$alias' in the {from} stack, something is wrong");
+ }
+
+ shift @outer_from; # the new subquery will represent this alias, so get rid of it
+ }
+
# decide which parts of the join will remain on the inside
#
}
# construct the inner $from for the subquery
- my $inner_from = [ $self_ident ];
- if (keys %inner_joins) {
- for my $j (@$from) {
- push @$inner_from, $j if $inner_joins{$j->[0]{-alias}};
- }
+ my $inner_from = [ $select_root ];
+ for my $j (@$from) {
+ push @$inner_from, $j if $inner_joins{$j->[0]{-alias}};
+ }
- # if a multi-type join was needed in the subquery ("multi" is indicated by
- # presence in {collapse}) - add a group_by to simulate the collapse in the subq
- for my $alias (keys %inner_joins) {
+ # if a multi-type join was needed in the subquery ("multi" is indicated by
+ # presence in {collapse}) - add a group_by to simulate the collapse in the subq
- # the dot comes from some weirdness in collapse
- # remove after the rewrite
- if ($attrs->{collapse}{".$alias"}) {
- $sub_attrs->{group_by} = $sub_select;
- last;
- }
+ for my $alias (keys %inner_joins) {
+
+ # the dot comes from some weirdness in collapse
+ # remove after the rewrite
+ if ($attrs->{collapse}{".$alias"}) {
+ $sub_attrs->{group_by} = $sub_select;
+ last;
}
}
$sub_attrs
);
- # put it back in $from
- unshift @$from, { $alias => $subq };
+ # put it in the new {from}
+ unshift @outer_from, { $alias => $subq };
# This is totally horrific - the $where ends up in both the inner and outer query
# Unfortunately not much can be done until SQLA2 introspection arrives
#
# OTOH it can be seen as a plus: <ash> (notes that this query would make a DBA cry ;)
- return ($from, $select, $where, $attrs);
+ return (\@outer_from, $select, $where, $attrs);
}
sub _resolve_ident_sources {
my $sep = $self->_sql_maker_opts->{name_sep} || '.';
$sep = "\Q$sep\E";
-
+
my %return;
foreach my $col (@{$colnames}) {
$col =~ m/^ (?: ([^$sep]+) $sep)? (.+) $/x;
return \%return;
}
-sub count {
- my ($self, $source, $attrs) = @_;
-
- my $tmp_attrs = { %$attrs };
-
- # take off any limits, record_filter is cdbi, and no point of ordering a count
- delete $tmp_attrs->{$_} for (qw/select as rows offset order_by record_filter/);
-
- # overwrite the selector
- $tmp_attrs->{select} = { count => '*' };
-
- my $tmp_rs = $source->resultset_class->new($source, $tmp_attrs);
- my ($count) = $tmp_rs->cursor->next;
-
- # if the offset/rows attributes are still present, we did not use
- # a subquery, so we need to make the calculations in software
- $count -= $attrs->{offset} if $attrs->{offset};
- $count = $attrs->{rows} if $attrs->{rows} and $attrs->{rows} < $count;
- $count = 0 if ($count < 0);
-
- return $count;
-}
-
-sub count_grouped {
- my ($self, $source, $attrs) = @_;
-
- # copy for the subquery, we need to do some adjustments to it too
- my $sub_attrs = { %$attrs };
-
- # these can not go in the subquery, and there is no point of ordering it
- delete $sub_attrs->{$_} for qw/collapse 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
- # simply deleting group_by suffices, as the code below will re-fill it
- # Note: we check $attrs, as $sub_attrs has collapse deleted
- if (ref $attrs->{collapse} and keys %{$attrs->{collapse}} ) {
- delete $sub_attrs->{group_by};
- }
-
- $sub_attrs->{group_by} ||= [ map { "$attrs->{alias}.$_" } ($source->primary_columns) ];
- $sub_attrs->{select} = $self->_grouped_count_select ($source, $sub_attrs);
-
- $attrs->{from} = [{
- count_subq => $source->resultset_class->new ($source, $sub_attrs )->as_query
- }];
-
- # the subquery replaces this
- delete $attrs->{$_} for qw/where bind collapse group_by having having_bind rows offset/;
-
- return $self->count ($source, $attrs);
+# Returns a counting SELECT for a simple count
+# query. Abstracted so that a storage could override
+# this to { count => 'firstcol' } or whatever makes
+# sense as a performance optimization
+sub _count_select {
+ #my ($self, $source, $rs_attrs) = @_;
+ return { count => '*' };
}
+# Returns a SELECT which will end up in the subselect
+# There may or may not be a group_by, as the subquery
+# might have been called to accomodate a limit
#
-# Returns a SELECT to go with a supplied GROUP BY
-# (caled by count_grouped so a group_by is present)
-# Most databases expect them to match, but some
-# choke in various ways.
+# Most databases would be happy with whatever ends up
+# here, but some choke in various ways.
#
-sub _grouped_count_select {
- my ($self, $source, $rs_args) = @_;
- return $rs_args->{group_by};
+sub _subq_count_select {
+ my ($self, $source, $rs_attrs) = @_;
+ return $rs_attrs->{group_by} if $rs_attrs->{group_by};
+
+ my @pcols = map { join '.', $rs_attrs->{alias}, $_ } ($source->primary_columns);
+ return @pcols ? \@pcols : [ 1 ];
}
+
sub source_bind_attributes {
my ($self, $source) = @_;
projects / dbsrgits/DBIx-Class.git / blobdiff