#
# This module contains code that should never have seen the light of day,
# does not belong in the Storage, or is otherwise unfit for public
-# display. The arrival of SQLA2 should immediately oboslete 90% of this
+# display. The arrival of SQLA2 should immediately obsolete 90% of this
#
use strict;
use base 'DBIx::Class::Storage';
use mro 'c3';
-use Carp::Clan qw/^DBIx::Class/;
+use List::Util 'first';
+use Scalar::Util 'blessed';
+use Sub::Name 'subname';
+use namespace::clean;
#
# This code will remove non-selecting/non-restricting joins from
# {from} specs, aiding the RDBMS query optimizer
#
sub _prune_unused_joins {
- my ($self) = shift;
-
+ my $self = shift;
my ($from, $select, $where, $attrs) = @_;
+ return $from unless $self->_use_join_optimizer;
+
if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY') {
return $from; # only standard {from} specs are supported
}
my $aliastypes = $self->_resolve_aliastypes_from_select_args(@_);
+ my $orig_joins = delete $aliastypes->{joining};
+ my $orig_multiplying = $aliastypes->{multiplying};
+
# a grouped set will not be affected by amount of rows. Thus any
# {multiplying} joins can go
- delete $aliastypes->{multiplying} if $attrs->{group_by};
-
+ delete $aliastypes->{multiplying}
+ if $attrs->{_force_prune_multiplying_joins} or $attrs->{group_by};
my @newfrom = $from->[0]; # FROM head is always present
- my %need_joins = (map { %{$_||{}} } (values %$aliastypes) );
+ my %need_joins;
+
+ for (values %$aliastypes) {
+ # add all requested aliases
+ $need_joins{$_} = 1 for keys %$_;
+
+ # add all their parents (as per joinpath which is an AoH { table => alias })
+ $need_joins{$_} = 1 for map { values %$_ } map { @{$_->{-parents}} } values %$_;
+ }
+
for my $j (@{$from}[1..$#$from]) {
push @newfrom, $j if (
- (! $j->[0]{-alias}) # legacy crap
+ (! defined $j->[0]{-alias}) # legacy crap
||
$need_joins{$j->[0]{-alias}}
);
}
- return \@newfrom;
+ return ( \@newfrom, {
+ multiplying => { map { $need_joins{$_} ? ($_ => $orig_multiplying->{$_}) : () } keys %$orig_multiplying },
+ %$aliastypes,
+ joining => { map { $_ => $orig_joins->{$_} } keys %need_joins },
+ } );
}
#
# This is the code producing joined subqueries like:
-# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
+# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
#
sub _adjust_select_args_for_complex_prefetch {
my ($self, $from, $select, $where, $attrs) = @_;
- $self->throw_exception ('Nothing to prefetch... how did we get here?!')
- if not @{$attrs->{_prefetch_select}};
-
$self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY');
+ my $root_alias = $attrs->{alias};
# generate inner/outer attribute lists, remove stuff that doesn't apply
my $outer_attrs = { %$attrs };
- delete $outer_attrs->{$_} for qw/where bind rows offset group_by having/;
+ delete @{$outer_attrs}{qw(where bind rows offset group_by _grouped_by_distinct having)};
my $inner_attrs = { %$attrs };
- delete $inner_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/;
+ delete @{$inner_attrs}{qw(from for collapse select as _related_results_construction)};
-
- # bring over all non-collapse-induced order_by into the inner query (if any)
- # the outer one will have to keep them all
- delete $inner_attrs->{order_by};
- if (my $ord_cnt = @{$outer_attrs->{order_by}} - @{$outer_attrs->{_collapse_order_by}} ) {
- $inner_attrs->{order_by} = [
- @{$outer_attrs->{order_by}}[ 0 .. $ord_cnt - 1]
- ];
- }
+ # there is no point of ordering the insides if there is no limit
+ delete $inner_attrs->{order_by} if (
+ delete $inner_attrs->{_order_is_artificial}
+ or
+ ! $inner_attrs->{rows}
+ );
# generate the inner/outer select lists
# for inside we consider only stuff *not* brought in by the prefetch
# on the outside we substitute any function for its alias
my $outer_select = [ @$select ];
- my $inner_select = [];
- for my $i (0 .. ( @$outer_select - @{$outer_attrs->{_prefetch_select}} - 1) ) {
+ my $inner_select;
+
+ my ($root_node, $root_node_offset);
+
+ for my $i (0 .. $#$from) {
+ my $node = $from->[$i];
+ my $h = (ref $node eq 'HASH') ? $node
+ : (ref $node eq 'ARRAY' and ref $node->[0] eq 'HASH') ? $node->[0]
+ : next
+ ;
+
+ if ( ($h->{-alias}||'') eq $root_alias and $h->{-rsrc} ) {
+ $root_node = $h;
+ $root_node_offset = $i;
+ last;
+ }
+ }
+
+ $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
+ unless $root_node;
+
+ # use the heavy duty resolver to take care of aliased/nonaliased naming
+ my $colinfo = $self->_resolve_column_info($from);
+ my $selected_root_columns;
+
+ for my $i (0 .. $#$outer_select) {
my $sel = $outer_select->[$i];
+ next if (
+ $colinfo->{$sel} and $colinfo->{$sel}{-source_alias} ne $root_alias
+ );
+
if (ref $sel eq 'HASH' ) {
$sel->{-as} ||= $attrs->{as}[$i];
- $outer_select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "inner_column_$i") );
+ $outer_select->[$i] = join ('.', $root_alias, ($sel->{-as} || "inner_column_$i") );
+ }
+ elsif (! ref $sel and my $ci = $colinfo->{$sel}) {
+ $selected_root_columns->{$ci->{-colname}} = 1;
}
push @$inner_select, $sel;
push @{$inner_attrs->{as}}, $attrs->{as}[$i];
}
- # construct the inner $from for the subquery
- # we need to prune first, because this will determine if we need a group_by below
- my $inner_from = $self->_prune_unused_joins ($from, $inner_select, $where, $inner_attrs);
-
- # if a multi-type join was needed in the subquery - add a group_by to simulate the
- # collapse in the subq
- $inner_attrs->{group_by} ||= $inner_select
- if List::Util::first
- { ! $_->[0]{-is_single} }
- (@{$inner_from}[1 .. $#$inner_from])
- ;
-
- # generate the subquery
- my $subq = $self->_select_args_to_query (
- $inner_from,
- $inner_select,
+ # We will need to fetch all native columns in the inner subquery, which may
+ # be a part of an *outer* join condition, or an order_by (which needs to be
+ # preserved outside)
+ # We can not just fetch everything because a potential has_many restricting
+ # join collapse *will not work* on heavy data types.
+ my $connecting_aliastypes = $self->_resolve_aliastypes_from_select_args(
+ $from,
+ [],
$where,
- $inner_attrs,
+ $inner_attrs
);
- my $subq_joinspec = {
- -alias => $attrs->{alias},
- -source_handle => $inner_from->[0]{-source_handle},
- $attrs->{alias} => $subq,
+ for (sort map { keys %{$_->{-seen_columns}||{}} } map { values %$_ } values %$connecting_aliastypes) {
+ my $ci = $colinfo->{$_} or next;
+ if (
+ $ci->{-source_alias} eq $root_alias
+ and
+ ! $selected_root_columns->{$ci->{-colname}}++
+ ) {
+ # adding it to both to keep limits not supporting dark selectors happy
+ push @$inner_select, $ci->{-fq_colname};
+ push @{$inner_attrs->{as}}, $ci->{-fq_colname};
+ }
+ }
+
+ # construct the inner $from and lock it in a subquery
+ # we need to prune first, because this will determine if we need a group_by below
+ # throw away all non-selecting, non-restricting multijoins
+ # (since we def. do not care about multiplication those inside the subquery)
+ my $inner_subq = do {
+
+ # must use it here regardless of user requests
+ local $self->{_use_join_optimizer} = 1;
+
+ # throw away multijoins since we def. do not care about those inside the subquery
+ my ($inner_from, $inner_aliastypes) = $self->_prune_unused_joins ($from, $inner_select, $where, {
+ %$inner_attrs, _force_prune_multiplying_joins => 1
+ });
+
+ # uh-oh a multiplier (which is not us) left in, this is a problem
+ if (
+ $inner_aliastypes->{multiplying}
+ and
+ # if there are user-supplied groups - assume user knows wtf they are up to
+ ( ! $inner_aliastypes->{grouping} or $inner_attrs->{_grouped_by_distinct} )
+ and
+ my @multipliers = grep { $_ ne $root_alias } keys %{$inner_aliastypes->{multiplying}}
+ ) {
+
+ # if none of the multipliers came from an order_by (guaranteed to have been combined
+ # with a limit) - easy - just slap a group_by to simulate a collapse and be on our way
+ if (
+ ! $inner_aliastypes->{ordering}
+ or
+ ! first { $inner_aliastypes->{ordering}{$_} } @multipliers
+ ) {
+
+ my $unprocessed_order_chunks;
+ ($inner_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ({
+ %$inner_attrs,
+ from => $inner_from,
+ select => $inner_select,
+ });
+
+ $self->throw_exception (
+ 'A required group_by clause could not be constructed automatically due to a complex '
+ . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable '
+ . 'group_by by hand'
+ ) if $unprocessed_order_chunks;
+ }
+ else {
+ # We need to order by external columns and group at the same time
+ # so we can calculate the proper limit
+ # This doesn't really make sense in SQL, however from DBICs point
+ # of view is rather valid (order the leftmost objects by whatever
+ # criteria and get the offset/rows many). There is a way around
+ # this however in SQL - we simply tae the direction of each piece
+ # of the foreign order and convert them to MIN(X) for ASC or MAX(X)
+ # for DESC, and group_by the root columns. The end result should be
+ # exactly what we expect
+
+ # supplement the main selection with pks if not already there,
+ # as they will have to be a part of the group_by to collapse
+ # things properly
+ my $cur_sel = { map { $_ => 1 } @$inner_select };
+
+ my @pks = map { "$root_alias.$_" } $root_node->{-rsrc}->primary_columns
+ or $self->throw_exception( sprintf
+ 'Unable to perform complex limited prefetch off %s without declared primary key',
+ $root_node->{-rsrc}->source_name,
+ );
+ for my $col (@pks) {
+ push @$inner_select, $col
+ unless $cur_sel->{$col}++;
+ }
+
+ # wrap any part of the order_by that "responds" to an ordering alias
+ # into a MIN/MAX
+ # FIXME - this code is a joke, will need to be completely rewritten in
+ # the DQ branch. But I need to push a POC here, otherwise the
+ # pesky tests won't pass
+ my $sql_maker = $self->sql_maker;
+ my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
+ my $own_re = qr/ $lquote \Q$root_alias\E $rquote $sep | \b \Q$root_alias\E $sep /x;
+ my @order_chunks = map { ref $_ eq 'ARRAY' ? $_ : [ $_ ] } $sql_maker->_order_by_chunks($attrs->{order_by});
+ my @new_order = map { \$_ } @order_chunks;
+ my $inner_columns_info = $self->_resolve_column_info($inner_from);
+
+ # loop through and replace stuff that is not "ours" with a min/max func
+ # everything is a literal at this point, since we are likely properly
+ # quoted and stuff
+ for my $i (0 .. $#new_order) {
+ my $chunk = $order_chunks[$i][0];
+
+ # skip ourselves
+ next if $chunk =~ $own_re;
+
+ ($chunk, my $is_desc) = $sql_maker->_split_order_chunk($chunk);
+
+ # maybe our own unqualified column
+ my $ord_bit = (
+ $lquote and $sep and $chunk =~ /^ $lquote ([^$sep]+) $rquote $/x
+ ) ? $1 : $chunk;
+
+ next if (
+ $ord_bit
+ and
+ $inner_columns_info->{$ord_bit}
+ and
+ $inner_columns_info->{$ord_bit}{-source_alias} eq $root_alias
+ );
+
+ $new_order[$i] = \[
+ sprintf(
+ '%s(%s)%s',
+ ($is_desc ? 'MAX' : 'MIN'),
+ $chunk,
+ ($is_desc ? ' DESC' : ''),
+ ),
+ @ {$order_chunks[$i]} [ 1 .. $#{$order_chunks[$i]} ]
+ ];
+ }
+
+ $inner_attrs->{order_by} = \@new_order;
+
+ # do not care about leftovers here - it will be all the functions
+ # we just created
+ ($inner_attrs->{group_by}) = $self->_group_over_selection ({
+ %$inner_attrs,
+ from => $inner_from,
+ select => $inner_select,
+ });
+ }
+ }
+
+ # we already optimized $inner_from above
+ # and already local()ized
+ $self->{_use_join_optimizer} = 0;
+
+ # generate the subquery
+ $self->_select_args_to_query (
+ $inner_from,
+ $inner_select,
+ $where,
+ $inner_attrs,
+ );
};
# Generate the outer from - this is relatively easy (really just replace
# - it is part of the restrictions, in which case we need to collapse the outer
# result by tackling yet another group_by to the outside of the query
- # normalize a copy of $from, so it will be easier to work with further
- # down (i.e. promote the initial hashref to an AoH)
+ # work on a shallow copy
$from = [ @$from ];
- $from->[0] = [ $from->[0] ];
- # so first generate the outer_from, up to the substitution point
my @outer_from;
- while (my $j = shift @$from) {
- if ($j->[0]{-alias} eq $attrs->{alias}) { # time to swap
- push @outer_from, [
- $subq_joinspec,
- @{$j}[1 .. $#$j],
- ];
- last; # we'll take care of what's left in $from below
- }
- else {
- push @outer_from, $j;
- }
+
+ # we may not be the head
+ if ($root_node_offset) {
+ # first generate the outer_from, up and including the substitution point
+ @outer_from = splice @$from, 0, $root_node_offset;
+
+ push @outer_from, [
+ {
+ -alias => $root_alias,
+ -rsrc => $root_node->{-rsrc},
+ $root_alias => $inner_subq,
+ },
+ @{$from->[0]}[1 .. $#{$from->[0]}],
+ ];
}
+ else {
+ @outer_from = {
+ -alias => $root_alias,
+ -rsrc => $root_node->{-rsrc},
+ $root_alias => $inner_subq,
+ };
+ }
+
+ shift @$from; # what we just replaced above
- # scan the from spec against different attributes, and see which joins are needed
+ # scan the *remaining* from spec against different attributes, and see which joins are needed
# in what role
- my $outer_aliastypes =
+ my $outer_aliastypes = $outer_attrs->{_aliastypes} =
$self->_resolve_aliastypes_from_select_args( $from, $outer_select, $where, $outer_attrs );
+ # unroll parents
+ my ($outer_select_chain, @outer_nonselecting_chains) = map { +{
+ map { $_ => 1 } map { values %$_} map { @{$_->{-parents}} } values %{ $outer_aliastypes->{$_} || {} }
+ } } qw/selecting restricting grouping ordering/;
+
# see what's left - throw away if not selecting/restricting
- # also throw in a group_by if restricting to guard against
- # cross-join explosions
- #
+ # also throw in a group_by if a non-selecting multiplier,
+ # to guard against cross-join explosions
+ my $need_outer_group_by;
while (my $j = shift @$from) {
my $alias = $j->[0]{-alias};
- if ($outer_aliastypes->{selecting}{$alias}) {
- push @outer_from, $j;
+ if (
+ $outer_select_chain->{$alias}
+ ) {
+ push @outer_from, $j
}
- elsif ($outer_aliastypes->{restricting}{$alias}) {
+ elsif (first { $_->{$alias} } @outer_nonselecting_chains ) {
push @outer_from, $j;
- $outer_attrs->{group_by} ||= $outer_select unless $j->[0]{-is_single};
+ $need_outer_group_by ||= $outer_aliastypes->{multiplying}{$alias} ? 1 : 0;
}
}
- # demote the outer_from head
- $outer_from[0] = $outer_from[0][0];
+ if ( $need_outer_group_by and $attrs->{_grouped_by_distinct} ) {
+ my $unprocessed_order_chunks;
+ ($outer_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ({
+ %$outer_attrs,
+ from => \@outer_from,
+ select => $outer_select,
+ });
+
+ $self->throw_exception (
+ 'A required group_by clause could not be constructed automatically due to a complex '
+ . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable '
+ . 'group_by by hand'
+ ) if $unprocessed_order_chunks;
+
+ }
# 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, and even
# then if where conditions apply to the *right* side of the prefetch, you may have
# to both filter the inner select (e.g. to apply a limit) and then have to re-filter
- # the outer select to exclude joins you didin't want in the first place
+ # the outer select to exclude joins you didn't want in the first place
#
# OTOH it can be seen as a plus: <ash> (notes that this query would make a DBA cry ;)
return (\@outer_from, $outer_select, $where, $outer_attrs);
#
# Due to a lack of SQLA2 we fall back to crude scans of all the
# select/where/order/group attributes, in order to determine what
-# aliases are neded to fulfill the query. This information is used
+# aliases are needed to fulfill the query. This information is used
# throughout the code to prune unnecessary JOINs from the queries
# in an attempt to reduce the execution time.
# Although the method is pretty horrific, the worst thing that can
or next;
$alias_list->{$al} = $j;
- $aliases_by_type->{multiplying}{$al} = 1
- unless $j->{-is_single};
+ $aliases_by_type->{multiplying}{$al} ||= { -parents => $j->{-join_path}||[] } if (
+ # not array == {from} head == can't be multiplying
+ ( ref($_) eq 'ARRAY' and ! $j->{-is_single} )
+ or
+ # a parent of ours is already a multiplier
+ ( grep { $aliases_by_type->{multiplying}{$_} } @{ $j->{-join_path}||[] } )
+ );
}
- # get a column to source/alias map (including unqualified ones)
+ # get a column to source/alias map (including unambiguous unqualified ones)
my $colinfo = $self->_resolve_column_info ($from);
# set up a botched SQLA
my $sql_maker = $self->sql_maker;
- my $sep = quotemeta ($self->_sql_maker_opts->{name_sep} || '.');
- my ($orig_lquote, $orig_rquote) = map { quotemeta $_ } (do {
- if (ref $sql_maker->{quote_char} eq 'ARRAY') {
- @{$sql_maker->{quote_char}}
- }
- else {
- ($sql_maker->{quote_char} || '') x 2;
- }
- });
+ # these are throw away results, do not pollute the bind stack
+ local $sql_maker->{select_bind};
+ local $sql_maker->{where_bind};
+ local $sql_maker->{group_bind};
+ local $sql_maker->{having_bind};
+ local $sql_maker->{from_bind};
+
+ # we can't scan properly without any quoting (\b doesn't cut it
+ # everywhere), so unless there is proper quoting set - use our
+ # own weird impossible character.
+ # Also in the case of no quoting, we need to explicitly disable
+ # name_sep, otherwise sorry nasty legacy syntax like
+ # { 'count(foo.id)' => { '>' => 3 } } will stop working >:(
+ local $sql_maker->{quote_char} = $sql_maker->{quote_char};
+ local $sql_maker->{name_sep} = $sql_maker->{name_sep};
+
+ unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
+ $sql_maker->{quote_char} = ["\x00", "\xFF"];
+ # if we don't unset it we screw up retarded but unfortunately working
+ # 'MAX(foo.bar)' => { '>', 3 }
+ $sql_maker->{name_sep} = '';
+ }
- local $sql_maker->{quote_char} = "\x00"; # so that we can regex away
+ my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
# generate sql chunks
my $to_scan = {
restricting => [
$sql_maker->_recurse_where ($where),
- $sql_maker->_order_by({
- map { $_ => $attrs->{$_} } (qw/group_by having/)
- }),
+ $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} }),
+ ],
+ grouping => [
+ $sql_maker->_parse_rs_attrs ({ group_by => $attrs->{group_by} }),
+ ],
+ joining => [
+ $sql_maker->_recurse_from (
+ ref $from->[0] eq 'ARRAY' ? $from->[0][0] : $from->[0],
+ @{$from}[1 .. $#$from],
+ ),
],
selecting => [
- $self->_parse_order_by ($attrs->{order_by}, $sql_maker),
$sql_maker->_recurse_fields ($select),
],
+ ordering => [
+ map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker),
+ ],
};
# throw away empty chunks
$_ = [ map { $_ || () } @$_ ] for values %$to_scan;
- # first loop through all fully qualified columns and get the corresponding
+ # first see if we have any exact matches (qualified or unqualified)
+ for my $type (keys %$to_scan) {
+ for my $piece (@{$to_scan->{$type}}) {
+ if ($colinfo->{$piece} and my $alias = $colinfo->{$piece}{-source_alias}) {
+ $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
+ $aliases_by_type->{$type}{$alias}{-seen_columns}{$colinfo->{$piece}{-fq_colname}} = $piece;
+ }
+ }
+ }
+
+ # now loop through all fully qualified columns and get the corresponding
# alias (should work even if they are in scalarrefs)
for my $alias (keys %$alias_list) {
my $al_re = qr/
- \x00 $alias \x00 $sep
+ $lquote $alias $rquote $sep (?: $lquote ([^$rquote]+) $rquote )?
|
- \b $alias $sep
+ \b $alias \. ([^\s\)\($rquote]+)?
/x;
- # add matching for possible quoted literal sql
- $al_re = qr/ $al_re | $orig_lquote $alias $orig_rquote /x
- if ($orig_lquote && $orig_rquote);
-
-
for my $type (keys %$to_scan) {
for my $piece (@{$to_scan->{$type}}) {
- $aliases_by_type->{$type}{$alias} = 1 if ($piece =~ $al_re);
+ if (my @matches = $piece =~ /$al_re/g) {
+ $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
+ $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = "$alias.$_"
+ for grep { defined $_ } @matches;
+ }
}
}
}
# now loop through unqualified column names, and try to locate them within
# the chunks
for my $col (keys %$colinfo) {
- next if $col =~ $sep; # if column is qualified it was caught by the above
-
- my $col_re = qr/ \x00 $col \x00 /x;
+ next if $col =~ / \. /x; # if column is qualified it was caught by the above
- $col_re = qr/ $col_re | $orig_lquote $col $orig_rquote /x
- if ($orig_lquote && $orig_rquote);
+ my $col_re = qr/ $lquote ($col) $rquote /x;
for my $type (keys %$to_scan) {
for my $piece (@{$to_scan->{$type}}) {
- $aliases_by_type->{$type}{$colinfo->{$col}{-source_alias}} = 1 if ($piece =~ $col_re);
+ if ( my @matches = $piece =~ /$col_re/g) {
+ my $alias = $colinfo->{$col}{-source_alias};
+ $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
+ $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = $_
+ for grep { defined $_ } @matches;
+ }
}
}
}
# Add any non-left joins to the restriction list (such joins are indeed restrictions)
for my $j (values %$alias_list) {
my $alias = $j->{-alias} or next;
- $aliases_by_type->{restricting}{$alias} = 1 if (
+ $aliases_by_type->{restricting}{$alias} ||= { -parents => $j->{-join_path}||[] } if (
(not $j->{-join_type})
or
($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
);
}
- # mark all join parents as mentioned
- # (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too )
- for my $type (keys %$aliases_by_type) {
- for my $alias (keys %{$aliases_by_type->{$type}}) {
- $aliases_by_type->{$type}{$_} = 1
- for (map { values %$_ } @{ $alias_list->{$alias}{-join_path} || [] });
- }
+ for (keys %$aliases_by_type) {
+ delete $aliases_by_type->{$_} unless keys %{$aliases_by_type->{$_}};
}
return $aliases_by_type;
}
+# This is the engine behind { distinct => 1 }
+sub _group_over_selection {
+ my ($self, $attrs) = @_;
+
+ my $colinfos = $self->_resolve_column_info ($attrs->{from});
+
+ my (@group_by, %group_index);
+
+ # the logic is: if it is a { func => val } we assume an aggregate,
+ # otherwise if \'...' or \[...] we assume the user knows what is
+ # going on thus group over it
+ for (@{$attrs->{select}}) {
+ if (! ref($_) or ref ($_) ne 'HASH' ) {
+ push @group_by, $_;
+ $group_index{$_}++;
+ if ($colinfos->{$_} and $_ !~ /\./ ) {
+ # add a fully qualified version as well
+ $group_index{"$colinfos->{$_}{-source_alias}.$_"}++;
+ }
+ }
+ }
+
+ # add any order_by parts *from the main source* that are not already
+ # present in the group_by
+ # we need to be careful not to add any named functions/aggregates
+ # i.e. order_by => [ ... { count => 'foo' } ... ]
+ my @leftovers;
+ for ($self->_extract_order_criteria($attrs->{order_by})) {
+ # only consider real columns (for functions the user got to do an explicit group_by)
+ if (@$_ != 1) {
+ push @leftovers, $_;
+ next;
+ }
+ my $chunk = $_->[0];
+
+ if (
+ !$colinfos->{$chunk}
+ or
+ $colinfos->{$chunk}{-source_alias} ne $attrs->{alias}
+ ) {
+ push @leftovers, $_;
+ next;
+ }
+
+ $chunk = $colinfos->{$chunk}{-fq_colname};
+ push @group_by, $chunk unless $group_index{$chunk}++;
+ }
+
+ return wantarray
+ ? (\@group_by, (@leftovers ? \@leftovers : undef) )
+ : \@group_by
+ ;
+}
+
sub _resolve_ident_sources {
my ($self, $ident) = @_;
my $alias2source = {};
- my $rs_alias;
# the reason this is so contrived is that $ident may be a {from}
# structure, specifying multiple tables to join
- if ( Scalar::Util::blessed($ident) && $ident->isa("DBIx::Class::ResultSource") ) {
+ if ( blessed $ident && $ident->isa("DBIx::Class::ResultSource") ) {
# this is compat mode for insert/update/delete which do not deal with aliases
$alias2source->{me} = $ident;
- $rs_alias = 'me';
}
elsif (ref $ident eq 'ARRAY') {
my $tabinfo;
if (ref $_ eq 'HASH') {
$tabinfo = $_;
- $rs_alias = $tabinfo->{-alias};
}
if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') {
$tabinfo = $_->[0];
}
- $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-source_handle}->resolve
- if ($tabinfo->{-source_handle});
+ $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-rsrc}
+ if ($tabinfo->{-rsrc});
}
}
- return ($alias2source, $rs_alias);
+ return $alias2source;
}
# Takes $ident, \@column_names
# for all sources
sub _resolve_column_info {
my ($self, $ident, $colnames) = @_;
- my ($alias2src, $root_alias) = $self->_resolve_ident_sources($ident);
-
- my $sep = $self->_sql_maker_opts->{name_sep} || '.';
- my $qsep = quotemeta $sep;
+ my $alias2src = $self->_resolve_ident_sources($ident);
- my (%return, %seen_cols, @auto_colnames);
+ my (%seen_cols, @auto_colnames);
# compile a global list of column names, to be able to properly
# disambiguate unqualified column names (if at all possible)
my $rsrc = $alias2src->{$alias};
for my $colname ($rsrc->columns) {
push @{$seen_cols{$colname}}, $alias;
- push @auto_colnames, "$alias$sep$colname" unless $colnames;
+ push @auto_colnames, "$alias.$colname" unless $colnames;
}
}
grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols),
];
- COLUMN:
+ my (%return, $colinfos);
foreach my $col (@$colnames) {
- my ($alias, $colname) = $col =~ m/^ (?: ([^$qsep]+) $qsep)? (.+) $/x;
+ my ($source_alias, $colname) = $col =~ m/^ (?: ([^\.]+) \. )? (.+) $/x;
- unless ($alias) {
- # see if the column was seen exactly once (so we know which rsrc it came from)
- if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1) {
- $alias = $seen_cols{$colname}[0];
- }
- else {
- next COLUMN;
- }
- }
+ # if the column was seen exactly once - we know which rsrc it came from
+ $source_alias ||= $seen_cols{$colname}[0]
+ if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1);
- my $rsrc = $alias2src->{$alias};
- $return{$col} = $rsrc && {
- %{$rsrc->column_info($colname)},
+ next unless $source_alias;
+
+ my $rsrc = $alias2src->{$source_alias}
+ or next;
+
+ $return{$col} = {
+ %{
+ ( $colinfos->{$source_alias} ||= $rsrc->columns_info )->{$colname}
+ ||
+ $self->throw_exception(
+ "No such column '$colname' on source " . $rsrc->source_name
+ );
+ },
-result_source => $rsrc,
- -source_alias => $alias,
+ -source_alias => $source_alias,
+ -fq_colname => $col eq $colname ? "$source_alias.$col" : $col,
+ -colname => $colname,
};
+
+ $return{"$source_alias.$colname"} = $return{$col} if $col eq $colname;
}
return \%return;
# the top of the stack, and if not - make sure the chain is inner-joined down
# to the root.
#
-sub _straight_join_to_node {
+sub _inner_join_to_node {
my ($self, $from, $alias) = @_;
# subqueries and other oddness are naturally not supported
# So it looks like we will have to switch some stuff around.
# local() is useless here as we will be leaving the scope
# anyway, and deep cloning is just too fucking expensive
- # So replace the first hashref in the node arrayref manually
+ # So replace the first hashref in the node arrayref manually
my @new_from = ($from->[0]);
my $sw_idx = { map { (values %$_), 1 } @$switch_branch }; #there's one k/v per join-path
return \@new_from;
}
-# Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
-# a condition containing 'me' or other table prefixes will not work
-# at all. What this code tries to do (badly) is introspect the condition
-# and remove all column qualifiers. If it bails out early (returns undef)
-# the calling code should try another approach (e.g. a subquery)
-sub _strip_cond_qualifiers {
- my ($self, $where) = @_;
-
- my $cond = {};
-
- # No-op. No condition, we're updating/deleting everything
- return $cond unless $where;
-
- if (ref $where eq 'ARRAY') {
- $cond = [
- map {
- my %hash;
- foreach my $key (keys %{$_}) {
- $key =~ /([^.]+)$/;
- $hash{$1} = $_->{$key};
- }
- \%hash;
- } @$where
- ];
- }
- elsif (ref $where eq 'HASH') {
- if ( (keys %$where) == 1 && ( (keys %{$where})[0] eq '-and' )) {
- $cond->{-and} = [];
- my @cond = @{$where->{-and}};
- for (my $i = 0; $i < @cond; $i++) {
- my $entry = $cond[$i];
- my $hash;
- my $ref = ref $entry;
- if ($ref eq 'HASH' or $ref eq 'ARRAY') {
- $hash = $self->_strip_cond_qualifiers($entry);
- }
- elsif (! $ref) {
- $entry =~ /([^.]+)$/;
- $hash->{$1} = $cond[++$i];
- }
- else {
- $self->throw_exception ("_strip_cond_qualifiers() is unable to handle a condition reftype $ref");
- }
- push @{$cond->{-and}}, $hash;
- }
- }
- else {
- foreach my $key (keys %$where) {
- $key =~ /([^.]+)$/;
- $cond->{$1} = $where->{$key};
- }
- }
- }
- else {
- return undef;
- }
-
- return $cond;
-}
-
-sub _parse_order_by {
+sub _extract_order_criteria {
my ($self, $order_by, $sql_maker) = @_;
my $parser = sub {
- my ($sql_maker, $order_by) = @_;
+ my ($sql_maker, $order_by, $orig_quote_chars) = @_;
return scalar $sql_maker->_order_by_chunks ($order_by)
unless wantarray;
+ my ($lq, $rq, $sep) = map { quotemeta($_) } (
+ ($orig_quote_chars ? @$orig_quote_chars : $sql_maker->_quote_chars),
+ $sql_maker->name_sep
+ );
+
my @chunks;
- for my $chunk (map { ref $_ ? @$_ : $_ } ($sql_maker->_order_by_chunks ($order_by) ) ) {
- $chunk =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
+ for ($sql_maker->_order_by_chunks ($order_by) ) {
+ my $chunk = ref $_ ? [ @$_ ] : [ $_ ];
+ ($chunk->[0]) = $sql_maker->_split_order_chunk($chunk->[0]);
+
+ # order criteria may have come back pre-quoted (literals and whatnot)
+ # this is fragile, but the best we can currently do
+ $chunk->[0] =~ s/^ $lq (.+?) $rq $sep $lq (.+?) $rq $/"$1.$2"/xe
+ or $chunk->[0] =~ s/^ $lq (.+) $rq $/$1/x;
+
push @chunks, $chunk;
}
}
else {
$sql_maker = $self->sql_maker;
+
+ # pass these in to deal with literals coming from
+ # the user or the deep guts of prefetch
+ my $orig_quote_chars = [$sql_maker->_quote_chars];
+
local $sql_maker->{quote_char};
- return $parser->($sql_maker, $order_by);
+ return $parser->($sql_maker, $order_by, $orig_quote_chars);
+ }
+}
+
+sub _order_by_is_stable {
+ my ($self, $ident, $order_by, $where) = @_;
+
+ my $colinfo = $self->_resolve_column_info($ident, [
+ (map { $_->[0] } $self->_extract_order_criteria($order_by)),
+ $where ? @{$self->_extract_fixed_condition_columns($where)} :(),
+ ]);
+
+ return undef unless keys %$colinfo;
+
+ my $cols_per_src;
+ $cols_per_src->{$_->{-source_alias}}{$_->{-colname}} = $_ for values %$colinfo;
+
+ for (values %$cols_per_src) {
+ my $src = (values %$_)[0]->{-result_source};
+ return 1 if $src->_identifying_column_set($_);
+ }
+
+ return undef;
+}
+
+# this is almost identical to the above, except it accepts only
+# a single rsrc, and will succeed only if the first portion of the order
+# by is stable.
+# returns that portion as a colinfo hashref on success
+sub _main_source_order_by_portion_is_stable {
+ my ($self, $main_rsrc, $order_by, $where) = @_;
+
+ die "Huh... I expect a blessed result_source..."
+ if ref($main_rsrc) eq 'ARRAY';
+
+ my @ord_cols = map
+ { $_->[0] }
+ ( $self->_extract_order_criteria($order_by) )
+ ;
+ return unless @ord_cols;
+
+ my $colinfos = $self->_resolve_column_info($main_rsrc);
+
+ for (0 .. $#ord_cols) {
+ if (
+ ! $colinfos->{$ord_cols[$_]}
+ or
+ $colinfos->{$ord_cols[$_]}{-result_source} != $main_rsrc
+ ) {
+ $#ord_cols = $_ - 1;
+ last;
+ }
+ }
+
+ # we just truncated it above
+ return unless @ord_cols;
+
+ my $order_portion_ci = { map {
+ $colinfos->{$_}{-colname} => $colinfos->{$_},
+ $colinfos->{$_}{-fq_colname} => $colinfos->{$_},
+ } @ord_cols };
+
+ # since all we check here are the start of the order_by belonging to the
+ # top level $rsrc, a present identifying set will mean that the resultset
+ # is ordered by its leftmost table in a stable manner
+ #
+ # RV of _identifying_column_set contains unqualified names only
+ my $unqualified_idset = $main_rsrc->_identifying_column_set({
+ ( $where ? %{
+ $self->_resolve_column_info(
+ $main_rsrc, $self->_extract_fixed_condition_columns($where)
+ )
+ } : () ),
+ %$order_portion_ci
+ }) or return;
+
+ my $ret_info;
+ my %unqualified_idcols_from_order = map {
+ $order_portion_ci->{$_} ? ( $_ => $order_portion_ci->{$_} ) : ()
+ } @$unqualified_idset;
+
+ # extra optimization - cut the order_by at the end of the identifying set
+ # (just in case the user was stupid and overlooked the obvious)
+ for my $i (0 .. $#ord_cols) {
+ my $col = $ord_cols[$i];
+ my $unqualified_colname = $order_portion_ci->{$col}{-colname};
+ $ret_info->{$col} = { %{$order_portion_ci->{$col}}, -idx_in_order_subset => $i };
+ delete $unqualified_idcols_from_order{$ret_info->{$col}{-colname}};
+
+ # we didn't reach the end of the identifying portion yet
+ return $ret_info unless keys %unqualified_idcols_from_order;
+ }
+
+ die 'How did we get here...';
+}
+
+# returns an arrayref of column names which *definitely* have some
+# sort of non-nullable equality requested in the given condition
+# specification. This is used to figure out if a resultset is
+# constrained to a column which is part of a unique constraint,
+# which in turn allows us to better predict how ordering will behave
+# etc.
+#
+# this is a rudimentary, incomplete, and error-prone extractor
+# however this is OK - it is conservative, and if we can not find
+# something that is in fact there - the stack will recover gracefully
+# Also - DQ and the mst it rode in on will save us all RSN!!!
+sub _extract_fixed_condition_columns {
+ my ($self, $where, $nested) = @_;
+
+ return unless ref $where eq 'HASH';
+
+ my @cols;
+ for my $lhs (keys %$where) {
+ if ($lhs =~ /^\-and$/i) {
+ push @cols, ref $where->{$lhs} eq 'ARRAY'
+ ? ( map { $self->_extract_fixed_condition_columns($_, 1) } @{$where->{$lhs}} )
+ : $self->_extract_fixed_condition_columns($where->{$lhs}, 1)
+ ;
+ }
+ elsif ($lhs !~ /^\-/) {
+ my $val = $where->{$lhs};
+
+ push @cols, $lhs if (defined $val and (
+ ! ref $val
+ or
+ (ref $val eq 'HASH' and keys %$val == 1 and defined $val->{'='})
+ ));
+ }
}
+ return $nested ? @cols : \@cols;
}
1;
projects / dbsrgits/DBIx-Class.git / blobdiff