} @bind;
}
+sub _flatten_bind_params {
+ my ($self, @bind) = @_;
+
+ ### Turn @bind from something like this:
+ ### ( [ "artist", 1 ], [ "cdid", 1, 3 ] )
+ ### to this:
+ ### ( 1, 1, 3 )
+ return
+ map {
+ if ( defined( $_ && $_->[1] ) ) {
+ @{$_}[ 1 .. $#$_ ];
+ }
+ else { undef; }
+ } @bind;
+}
+
sub _query_start {
my ( $self, $sql, @bind ) = @_;
$self->throw_exception ('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/;
delete $sub_attrs->{$_} for qw/for collapse select order_by/;
-
my $alias = $attrs->{alias};
# create subquery select list
];
}
+ # mangle {from}
+ $from = [ @$from ];
+ my $select_root = shift @$from;
+ my @outer_from = @$from;
+
+ my %inner_joins;
+ my %join_info = map { $_->[0]{-alias} => $_->[0] } (@$from);
- # mangle the from, separating it into an outer and inner part
- my $self_ident = shift @$from;
- my %join_map = map { $_->[0]{-alias} => $_->[0]{-join_path} } (@$from);
+ # 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;
- my (%inner_joins, %outer_joins);
+ 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
+
+ # decide which parts of the join will remain on the inside
+ #
+ # this is not a very viable optimisation, but it was written
+ # before I realised this, so might as well remain. We can throw
+ # away _any_ branches of the join tree that are:
+ # 1) not mentioned in the condition/order
+ # 2) left-join leaves (or left-join leaf chains)
+ # Most of the join ocnditions will not satisfy this, but for real
+ # complex queries some might, and we might make some RDBMS happy.
#
- # resolve the prefetch-needed joins here as well, as the $attr->{prefetch}
- # is 1) resolved away 2) unreliable as it may be a result of search_related
- # and whatnot
#
# since we do not have introspectable SQLA, we fall back to ugly
# scanning of raw SQL for WHERE, and for pieces of ORDER BY
# in order to determine what goes into %inner_joins
# It may not be very efficient, but it's a reasonable stop-gap
{
- # produce stuff unquoted, so it's easier to scan
+ # produce stuff unquoted, so it can be scanned
my $sql_maker = $self->sql_maker;
local $sql_maker->{quote_char};
my $where_sql = $sql_maker->where ($where);
# sort needed joins
- for my $alias (keys %join_map) {
+ for my $alias (keys %join_info) {
+ # any table alias found on a column name in where or order_by
+ # gets included in %inner_joins
+ # Also any parent joins that are needed to reach this particular alias
for my $piece ($where_sql, @order_by ) {
if ($piece =~ /\b$alias\./) {
$inner_joins{$alias} = 1;
- $inner_joins{$_} = 1 for @{$join_map{$alias}};
- }
- }
-
- for my $sel (@$select) {
- if ($sel =~ /^$alias\./) {
- $outer_joins{$alias}++;
- $outer_joins{$_} = 1 for @{$join_map{$alias}};
}
}
}
}
- my $inner_from = [ $self_ident ];
- if (keys %inner_joins) {
- for my $j (@$from) {
- push @$inner_from, $j if $inner_joins{$j->[0]{-alias}};
+ # scan for non-leaf/non-left joins and mark as needed
+ # also mark all ancestor joins that are needed to reach this particular alias
+ # (e.g. join => { cds => 'tracks' } - tracks will bring cds too )
+ #
+ # traverse by the size of the -join_path i.e. reverse depth first
+ for my $alias (sort { @{$join_info{$b}{-join_path}} <=> @{$join_info{$a}{-join_path}} } (keys %join_info) ) {
+
+ my $j = $join_info{$alias};
+ $inner_joins{$alias} = 1 if (! $j->{-join_type} || ($j->{-join_type} !~ /^left$/i) );
+
+ if ($inner_joins{$alias}) {
+ $inner_joins{$_} = 1 for (@{$j->{-join_path}});
}
+ }
- # 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) {
+ # construct the inner $from for the subquery
+ my $inner_from = [ $select_root ];
+ for my $j (@$from) {
+ push @$inner_from, $j if $inner_joins{$j->[0]{-alias}};
+ }
- # the dot comes from some weirdness in collapse
- # remove after the rewrite
- if ($attrs->{collapse}{".$alias"}) {
- $sub_attrs->{group_by} = $sub_select;
- last;
- }
+ # 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 $alias (keys %inner_joins) {
+
+ # the dot comes from some weirdness in collapse
+ # remove after the rewrite
+ if ($attrs->{collapse}{".$alias"}) {
+ $sub_attrs->{group_by} = $sub_select;
+ last;
}
}
+ # generate the subquery
my $subq = $self->_select_args_to_query (
$inner_from,
$sub_select,
$sub_attrs
);
- my $outer_from = [ { me => $subq } ];
- if (keys %outer_joins) {
- for my $j (@$from) {
- push @$outer_from, $j if $outer_joins{$j->[0]{-alias}};
- }
- }
+ # put it in the new {from}
+ unshift @outer_from, { $alias => $subq };
- return ($outer_from, $select, {}, $attrs); # where ended up in the subquery, thus {}
+ # 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 (\@outer_from, $select, $where, $attrs);
}
sub _resolve_ident_sources {
return $alias2source;
}
-sub count {
- my ($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) = @_;
-
+
my $bind_attributes;
foreach my $column ($source->columns) {
-
+
my $data_type = $source->column_info($column)->{data_type} || '';
$bind_attributes->{$column} = $self->bind_attribute_by_data_type($data_type)
if $data_type;
projects / dbsrgits/DBIx-Class.git / blobdiff