1 package #hide from PAUSE
2 DBIx::Class::Storage::DBIHacks;
5 # This module contains code that should never have seen the light of day,
6 # does not belong in the Storage, or is otherwise unfit for public
7 # display. The arrival of SQLA2 should immediately obsolete 90% of this
13 use base 'DBIx::Class::Storage';
16 use List::Util 'first';
17 use Scalar::Util 'blessed';
18 use Sub::Name 'subname';
19 use Data::Query::Constants;
20 use Data::Query::ExprHelpers;
24 # This code will remove non-selecting/non-restricting joins from
25 # {from} specs, aiding the RDBMS query optimizer
27 sub _prune_unused_joins {
28 my ($self, $attrs) = @_;
30 # only standard {from} specs are supported, and we could be disabled in general
31 return ($attrs->{from}, {}) unless (
32 ref $attrs->{from} eq 'ARRAY'
36 ref $attrs->{from}[0] eq 'HASH'
38 ref $attrs->{from}[1] eq 'ARRAY'
40 $self->_use_join_optimizer
43 my $orig_aliastypes = $self->_resolve_aliastypes_from_select_args($attrs);
45 my $new_aliastypes = { %$orig_aliastypes };
47 # we will be recreating this entirely
48 my @reclassify = 'joining';
50 # a grouped set will not be affected by amount of rows. Thus any
51 # purely multiplicator classifications can go
52 # (will be reintroduced below if needed by something else)
53 push @reclassify, qw(multiplying premultiplied)
54 if $attrs->{_force_prune_multiplying_joins} or $attrs->{group_by};
56 # nuke what will be recalculated
57 delete @{$new_aliastypes}{@reclassify};
59 my @newfrom = $attrs->{from}[0]; # FROM head is always present
61 # recalculate what we need once the multipliers are potentially gone
62 # ignore premultiplies, since they do not add any value to anything
64 for ( @{$new_aliastypes}{grep { $_ ne 'premultiplied' } keys %$new_aliastypes }) {
65 # add all requested aliases
66 $need_joins{$_} = 1 for keys %$_;
68 # add all their parents (as per joinpath which is an AoH { table => alias })
69 $need_joins{$_} = 1 for map { values %$_ } map { @{$_->{-parents}} } values %$_;
72 for my $j (@{$attrs->{from}}[1..$#{$attrs->{from}}]) {
73 push @newfrom, $j if (
74 (! defined $j->[0]{-alias}) # legacy crap
76 $need_joins{$j->[0]{-alias}}
80 # we have a new set of joiners - for everything we nuked pull the classification
81 # off the original stack
82 for my $ctype (@reclassify) {
83 $new_aliastypes->{$ctype} = { map
84 { $need_joins{$_} ? ( $_ => $orig_aliastypes->{$ctype}{$_} ) : () }
85 keys %{$orig_aliastypes->{$ctype}}
89 return ( \@newfrom, $new_aliastypes );
93 # This is the code producing joined subqueries like:
94 # SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
96 sub _adjust_select_args_for_complex_prefetch {
97 my ($self, $attrs) = @_;
99 $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute') unless (
100 ref $attrs->{from} eq 'ARRAY'
102 @{$attrs->{from}} > 1
104 ref $attrs->{from}[0] eq 'HASH'
106 ref $attrs->{from}[1] eq 'ARRAY'
109 my $root_alias = $attrs->{alias};
111 # generate inner/outer attribute lists, remove stuff that doesn't apply
112 my $outer_attrs = { %$attrs };
113 delete @{$outer_attrs}{qw(from bind rows offset group_by _grouped_by_distinct having)};
115 my $inner_attrs = { %$attrs };
116 delete @{$inner_attrs}{qw(for collapse select as _related_results_construction)};
118 # there is no point of ordering the insides if there is no limit
119 delete $inner_attrs->{order_by} if (
120 delete $inner_attrs->{_order_is_artificial}
122 ! $inner_attrs->{rows}
125 # generate the inner/outer select lists
126 # for inside we consider only stuff *not* brought in by the prefetch
127 # on the outside we substitute any function for its alias
128 $outer_attrs->{select} = [ @{$attrs->{select}} ];
130 my ($root_node, $root_node_offset);
132 for my $i (0 .. $#{$inner_attrs->{from}}) {
133 my $node = $inner_attrs->{from}[$i];
134 my $h = (ref $node eq 'HASH') ? $node
135 : (ref $node eq 'ARRAY' and ref $node->[0] eq 'HASH') ? $node->[0]
139 if ( ($h->{-alias}||'') eq $root_alias and $h->{-rsrc} ) {
141 $root_node_offset = $i;
146 $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
149 # use the heavy duty resolver to take care of aliased/nonaliased naming
150 my $colinfo = $self->_resolve_column_info($inner_attrs->{from});
151 my $selected_root_columns;
153 for my $i (0 .. $#{$outer_attrs->{select}}) {
154 my $sel = $outer_attrs->{select}->[$i];
157 $colinfo->{$sel} and $colinfo->{$sel}{-source_alias} ne $root_alias
160 if (ref $sel eq 'HASH' ) {
161 $sel->{-as} ||= $attrs->{as}[$i];
162 $outer_attrs->{select}->[$i] = join ('.', $root_alias, ($sel->{-as} || "inner_column_$i") );
164 elsif (! ref $sel and my $ci = $colinfo->{$sel}) {
165 $selected_root_columns->{$ci->{-colname}} = 1;
168 push @{$inner_attrs->{select}}, $sel;
170 push @{$inner_attrs->{as}}, $attrs->{as}[$i];
173 # We will need to fetch all native columns in the inner subquery, which may
174 # be a part of an *outer* join condition, or an order_by (which needs to be
175 # preserved outside), or wheres. In other words everything but the inner
177 # We can not just fetch everything because a potential has_many restricting
178 # join collapse *will not work* on heavy data types.
179 my $connecting_aliastypes = $self->_resolve_aliastypes_from_select_args({
184 for (sort map { keys %{$_->{-seen_columns}||{}} } map { values %$_ } values %$connecting_aliastypes) {
185 my $ci = $colinfo->{$_} or next;
187 $ci->{-source_alias} eq $root_alias
189 ! $selected_root_columns->{$ci->{-colname}}++
191 # adding it to both to keep limits not supporting dark selectors happy
192 push @{$inner_attrs->{select}}, $ci->{-fq_colname};
193 push @{$inner_attrs->{as}}, $ci->{-fq_colname};
197 # construct the inner {from} and lock it in a subquery
198 # we need to prune first, because this will determine if we need a group_by below
199 # throw away all non-selecting, non-restricting multijoins
200 # (since we def. do not care about multiplication of the contents of the subquery)
201 my $inner_subq = do {
203 # must use it here regardless of user requests (vastly gentler on optimizer)
204 local $self->{_use_join_optimizer} = 1;
206 # throw away multijoins since we def. do not care about those inside the subquery
207 ($inner_attrs->{from}, my $inner_aliastypes) = $self->_prune_unused_joins ({
208 %$inner_attrs, _force_prune_multiplying_joins => 1
211 # uh-oh a multiplier (which is not us) left in, this is a problem for limits
212 # we will need to add a group_by to collapse the resultset for proper counts
214 grep { $_ ne $root_alias } keys %{ $inner_aliastypes->{multiplying} || {} }
216 # if there are user-supplied groups - assume user knows wtf they are up to
217 ( ! $inner_aliastypes->{grouping} or $inner_attrs->{_grouped_by_distinct} )
220 my $cur_sel = { map { $_ => 1 } @{$inner_attrs->{select}} };
222 # *possibly* supplement the main selection with pks if not already
223 # there, as they will have to be a part of the group_by to collapse
225 my $inner_select_with_extras;
226 my @pks = map { "$root_alias.$_" } $root_node->{-rsrc}->primary_columns
227 or $self->throw_exception( sprintf
228 'Unable to perform complex limited prefetch off %s without declared primary key',
229 $root_node->{-rsrc}->source_name,
232 push @{ $inner_select_with_extras ||= [ @{$inner_attrs->{select}} ] }, $col
233 unless $cur_sel->{$col}++;
236 ($inner_attrs->{group_by}, $inner_attrs->{order_by}) = $self->_group_over_selection({
238 $inner_select_with_extras ? ( select => $inner_select_with_extras ) : (),
239 _aliastypes => $inner_aliastypes,
243 # we already optimized $inner_attrs->{from} above
244 # and already local()ized
245 $self->{_use_join_optimizer} = 0;
247 # generate the subquery
248 $self->_select_args_to_query (
249 @{$inner_attrs}{qw(from select where)},
254 # Generate the outer from - this is relatively easy (really just replace
255 # the join slot with the subquery), with a major caveat - we can not
256 # join anything that is non-selecting (not part of the prefetch), but at
257 # the same time is a multi-type relationship, as it will explode the result.
259 # There are two possibilities here
260 # - either the join is non-restricting, in which case we simply throw it away
261 # - it is part of the restrictions, in which case we need to collapse the outer
262 # result by tackling yet another group_by to the outside of the query
264 # work on a shallow copy
265 my @orig_from = @{$attrs->{from}};
268 $outer_attrs->{from} = \ my @outer_from;
270 # we may not be the head
271 if ($root_node_offset) {
272 # first generate the outer_from, up to the substitution point
273 @outer_from = splice @orig_from, 0, $root_node_offset;
275 # substitute the subq at the right spot
278 -alias => $root_alias,
279 -rsrc => $root_node->{-rsrc},
280 $root_alias => $inner_subq,
282 # preserve attrs from what is now the head of the from after the splice
283 @{$orig_from[0]}[1 .. $#{$orig_from[0]}],
288 -alias => $root_alias,
289 -rsrc => $root_node->{-rsrc},
290 $root_alias => $inner_subq,
294 shift @orig_from; # what we just replaced above
296 # scan the *remaining* from spec against different attributes, and see which joins are needed
298 my $outer_aliastypes = $outer_attrs->{_aliastypes} =
299 $self->_resolve_aliastypes_from_select_args({ %$outer_attrs, from => \@orig_from });
302 my ($outer_select_chain, @outer_nonselecting_chains) = map { +{
303 map { $_ => 1 } map { values %$_} map { @{$_->{-parents}} } values %{ $outer_aliastypes->{$_} || {} }
304 } } qw/selecting restricting grouping ordering/;
306 # see what's left - throw away if not selecting/restricting
307 my $may_need_outer_group_by;
308 while (my $j = shift @orig_from) {
309 my $alias = $j->[0]{-alias};
312 $outer_select_chain->{$alias}
316 elsif (first { $_->{$alias} } @outer_nonselecting_chains ) {
317 push @outer_from, $j;
318 $may_need_outer_group_by ||= $outer_aliastypes->{multiplying}{$alias} ? 1 : 0;
322 # also throw in a synthetic group_by if a non-selecting multiplier,
323 # to guard against cross-join explosions
324 # the logic is somewhat fragile, but relies on the idea that if a user supplied
325 # a group by on their own - they know what they were doing
326 if ( $may_need_outer_group_by and $attrs->{_grouped_by_distinct} ) {
327 ($outer_attrs->{group_by}, $outer_attrs->{order_by}) = $self->_group_over_selection ({
329 from => \@outer_from,
333 # This is totally horrific - the {where} ends up in both the inner and outer query
334 # Unfortunately not much can be done until SQLA2 introspection arrives, and even
335 # then if where conditions apply to the *right* side of the prefetch, you may have
336 # to both filter the inner select (e.g. to apply a limit) and then have to re-filter
337 # the outer select to exclude joins you didn't want in the first place
339 # OTOH it can be seen as a plus: <ash> (notes that this query would make a DBA cry ;)
344 # I KNOW THIS SUCKS! GET SQLA2 OUT THE DOOR SO THIS CAN DIE!
346 # Due to a lack of SQLA2 we fall back to crude scans of all the
347 # select/where/order/group attributes, in order to determine what
348 # aliases are needed to fulfill the query. This information is used
349 # throughout the code to prune unnecessary JOINs from the queries
350 # in an attempt to reduce the execution time.
351 # Although the method is pretty horrific, the worst thing that can
352 # happen is for it to fail due to some scalar SQL, which in turn will
353 # result in a vocal exception.
354 sub _resolve_aliastypes_from_select_args {
355 my ( $self, $attrs ) = @_;
357 $self->throw_exception ('Unable to analyze custom {from}')
358 if ref $attrs->{from} ne 'ARRAY';
360 # what we will return
363 # see what aliases are there to work with
364 # and record who is a multiplier and who is premultiplied
366 for my $node (@{$attrs->{from}}) {
369 $j = $j->[0] if ref $j eq 'ARRAY';
370 my $al = $j->{-alias}
373 $alias_list->{$al} = $j;
375 $aliases_by_type->{multiplying}{$al} ||= { -parents => $j->{-join_path}||[] }
376 # not array == {from} head == can't be multiplying
377 if ref($node) eq 'ARRAY' and ! $j->{-is_single};
379 $aliases_by_type->{premultiplied}{$al} ||= { -parents => $j->{-join_path}||[] }
380 # parts of the path that are not us but are multiplying
381 if grep { $aliases_by_type->{multiplying}{$_} }
384 @{ $j->{-join_path}||[] }
387 # get a column to source/alias map (including unambiguous unqualified ones)
388 my $colinfo = $self->_resolve_column_info ($attrs->{from});
390 # set up a botched SQLA
391 my $sql_maker = $self->sql_maker;
393 # these are throw away results, do not pollute the bind stack
394 local $sql_maker->{select_bind};
395 local $sql_maker->{where_bind};
396 local $sql_maker->{group_bind};
397 local $sql_maker->{having_bind};
398 local $sql_maker->{from_bind};
400 # we can't scan properly without any quoting (\b doesn't cut it
401 # everywhere), so unless there is proper quoting set - use our
402 # own weird impossible character.
403 # Also in the case of no quoting, we need to explicitly disable
404 # name_sep, otherwise sorry nasty legacy syntax like
405 # { 'count(foo.id)' => { '>' => 3 } } will stop working >:(
406 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
407 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
409 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
410 $sql_maker->{quote_char} = ["\x00", "\xFF"];
411 # if we don't unset it we screw up retarded but unfortunately working
412 # 'MAX(foo.bar)' => { '>', 3 }
413 $sql_maker->{name_sep} = '';
416 # delete local is 5.12+
417 local @{$sql_maker}{qw(renderer converter)};
418 delete @{$sql_maker}{qw(renderer converter)};
420 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
422 # generate sql chunks
426 ? ($sql_maker->_recurse_where($attrs->{where}))[0]
430 ? ($sql_maker->_recurse_where($attrs->{having}))[0]
436 ? ($sql_maker->_render_sqla(group_by => $attrs->{group_by}))[0]
441 $sql_maker->_recurse_from (
442 ref $attrs->{from}[0] eq 'ARRAY' ? $attrs->{from}[0][0] : $attrs->{from}[0],
443 @{$attrs->{from}}[1 .. $#{$attrs->{from}}],
447 map { $sql_maker->_render_sqla(select_select => $_) =~ /^SELECT\s+(.+)/ } @{$attrs->{select}||[]},
450 map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker),
454 # throw away empty chunks and all 2-value arrayrefs: the thinking is that these are
455 # bind value specs left in by the sloppy renderer above. It is ok to do this
456 # at this point, since we are going to end up rewriting this crap anyway
457 for my $v (values %$to_scan) {
466 ( @$_ == 0 or @$_ == 2 )
471 require Data::Dumper::Concise;
472 $self->throw_exception("Unexpected ref in scan-plan: " . Data::Dumper::Concise::Dumper($v) );
481 # kill all selectors which look like a proper subquery
482 # this is a sucky heuristic *BUT* - if we get it wrong the query will simply
483 # fail to run, so we are relatively safe
484 $to_scan->{selecting} = [ grep {
485 $_ !~ / \A \s* \( \s* SELECT \s+ .+? \s+ FROM \s+ .+? \) \s* \z /xsi
486 } @{ $to_scan->{selecting} || [] } ];
488 # first see if we have any exact matches (qualified or unqualified)
489 for my $type (keys %$to_scan) {
490 for my $piece (@{$to_scan->{$type}}) {
491 if ($colinfo->{$piece} and my $alias = $colinfo->{$piece}{-source_alias}) {
492 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
493 $aliases_by_type->{$type}{$alias}{-seen_columns}{$colinfo->{$piece}{-fq_colname}} = $piece;
498 # now loop through all fully qualified columns and get the corresponding
499 # alias (should work even if they are in scalarrefs)
500 for my $alias (keys %$alias_list) {
502 $lquote $alias $rquote $sep (?: $lquote ([^$rquote]+) $rquote )?
504 \b $alias \. ([^\s\)\($rquote]+)?
507 for my $type (keys %$to_scan) {
508 for my $piece (@{$to_scan->{$type}}) {
509 if (my @matches = $piece =~ /$al_re/g) {
510 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
511 $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = "$alias.$_"
512 for grep { defined $_ } @matches;
518 # now loop through unqualified column names, and try to locate them within
520 for my $col (keys %$colinfo) {
521 next if $col =~ / \. /x; # if column is qualified it was caught by the above
523 my $col_re = qr/ $lquote ($col) $rquote /x;
525 for my $type (keys %$to_scan) {
526 for my $piece (@{$to_scan->{$type}}) {
527 if ( my @matches = $piece =~ /$col_re/g) {
528 my $alias = $colinfo->{$col}{-source_alias};
529 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
530 $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = $_
531 for grep { defined $_ } @matches;
537 # Add any non-left joins to the restriction list (such joins are indeed restrictions)
538 for my $j (values %$alias_list) {
539 my $alias = $j->{-alias} or next;
540 $aliases_by_type->{restricting}{$alias} ||= { -parents => $j->{-join_path}||[] } if (
541 (not $j->{-join_type})
543 ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
547 for (keys %$aliases_by_type) {
548 delete $aliases_by_type->{$_} unless keys %{$aliases_by_type->{$_}};
551 return $aliases_by_type;
554 # This is the engine behind { distinct => 1 } and the general
555 # complex prefetch grouper
556 sub _group_over_selection {
557 my ($self, $attrs) = @_;
559 my $colinfos = $self->_resolve_column_info ($attrs->{from});
561 my (@group_by, %group_index);
563 # the logic is: if it is a { func => val } we assume an aggregate,
564 # otherwise if \'...' or \[...] we assume the user knows what is
565 # going on thus group over it
566 for (@{$attrs->{select}}) {
567 if (! ref($_) or ref ($_) ne 'HASH' ) {
570 if ($colinfos->{$_} and $_ !~ /\./ ) {
571 # add a fully qualified version as well
572 $group_index{"$colinfos->{$_}{-source_alias}.$_"}++;
577 my $sql_maker = $self->sql_maker;
578 my @order_by = $self->_extract_order_criteria($attrs->{order_by}, $sql_maker)
579 or return (\@group_by, $attrs->{order_by});
581 # add any order_by parts that are not already present in the group_by
582 # to maintain SQL cross-compatibility and general sanity
584 # also in case the original selection is *not* unique, or in case part
585 # of the ORDER BY refers to a multiplier - we will need to replace the
586 # skipped order_by elements with their MIN/MAX equivalents as to maintain
587 # the proper overall order without polluting the group criteria (and
588 # possibly changing the outcome entirely)
590 my ($leftovers, @new_order_by, $order_chunks, $aliastypes);
592 my $group_already_unique = $self->_columns_comprise_identifying_set($colinfos, \@group_by);
594 for my $o_idx (0 .. $#order_by) {
596 # if the chunk is already a min/max function - there is nothing left to touch
597 next if $order_by[$o_idx][0] =~ /^ (?: min | max ) \s* \( .+ \) $/ix;
599 # only consider real columns (for functions the user got to do an explicit group_by)
602 @{$order_by[$o_idx]} != 1
604 # only declare an unknown *plain* identifier as "leftover" if we are called with
605 # aliastypes to examine. If there are none - we are still in _resolve_attrs, and
606 # can just assume the user knows what they want
607 ( ! ( $chunk_ci = $colinfos->{$order_by[$o_idx][0]} ) and $attrs->{_aliastypes} )
609 push @$leftovers, $order_by[$o_idx][0];
612 next unless $chunk_ci;
614 # no duplication of group criteria
615 next if $group_index{$chunk_ci->{-fq_colname}};
618 $attrs->{_aliastypes}
620 $self->_resolve_aliastypes_from_select_args({
621 from => $attrs->{from},
622 order_by => $attrs->{order_by},
624 ) if $group_already_unique;
626 # check that we are not ordering by a multiplier (if a check is requested at all)
628 $group_already_unique
630 ! $aliastypes->{multiplying}{$chunk_ci->{-source_alias}}
632 ! $aliastypes->{premultiplied}{$chunk_ci->{-source_alias}}
634 push @group_by, $chunk_ci->{-fq_colname};
635 $group_index{$chunk_ci->{-fq_colname}}++
638 # We need to order by external columns without adding them to the group
639 # (eiehter a non-unique selection, or a multi-external)
641 # This doesn't really make sense in SQL, however from DBICs point
642 # of view is rather valid (e.g. order the leftmost objects by whatever
643 # criteria and get the offset/rows many). There is a way around
644 # this however in SQL - we simply tae the direction of each piece
645 # of the external order and convert them to MIN(X) for ASC or MAX(X)
646 # for DESC, and group_by the root columns. The end result should be
647 # exactly what we expect
649 # FIXME - this code is a joke, will need to be completely rewritten in
650 # the DQ branch. But I need to push a POC here, otherwise the
651 # pesky tests won't pass
652 # wrap any part of the order_by that "responds" to an ordering alias
655 $order_chunks ||= do {
657 my $dq_node = $sql_maker->converter->_order_by_to_dq($attrs->{order_by});
659 while (is_Order($dq_node)) {
661 is_desc => $dq_node->{reverse},
662 dq_node => $dq_node->{by},
665 @{$c[-1]}{qw(sql bind)} = $sql_maker->_render_dq($dq_node->{by});
667 $dq_node = $dq_node->{from};
673 $new_order_by[$o_idx] = {
674 ($order_chunks->[$o_idx]{is_desc} ? '-desc' : '-asc') => \[
675 sprintf ( '%s( %s )',
676 ($order_chunks->[$o_idx]{is_desc} ? 'MAX' : 'MIN'),
677 $order_chunks->[$o_idx]{sql},
679 @{ $order_chunks->[$o_idx]{bind} || [] }
685 $self->throw_exception ( sprintf
686 'A required group_by clause could not be constructed automatically due to a complex '
687 . 'order_by criteria (%s). Either order_by columns only (no functions) or construct a suitable '
688 . 'group_by by hand',
689 join ', ', map { "'$_'" } @$leftovers,
692 # recreate the untouched order parts
694 $new_order_by[$_] ||= {
695 ( $order_chunks->[$_]{is_desc} ? '-desc' : '-asc' )
696 => \ $order_chunks->[$_]{dq_node}
697 } for ( 0 .. $#$order_chunks );
702 (@new_order_by ? \@new_order_by : $attrs->{order_by} ), # same ref as original == unchanged
706 sub _resolve_ident_sources {
707 my ($self, $ident) = @_;
709 my $alias2source = {};
711 # the reason this is so contrived is that $ident may be a {from}
712 # structure, specifying multiple tables to join
713 if ( blessed $ident && $ident->isa("DBIx::Class::ResultSource") ) {
714 # this is compat mode for insert/update/delete which do not deal with aliases
715 $alias2source->{me} = $ident;
717 elsif (ref $ident eq 'ARRAY') {
721 if (ref $_ eq 'HASH') {
724 if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') {
728 $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-rsrc}
729 if ($tabinfo->{-rsrc});
733 return $alias2source;
736 # Takes $ident, \@column_names
738 # returns { $column_name => \%column_info, ... }
739 # also note: this adds -result_source => $rsrc to the column info
741 # If no columns_names are supplied returns info about *all* columns
743 sub _resolve_column_info {
744 my ($self, $ident, $colnames) = @_;
745 my $alias2src = $self->_resolve_ident_sources($ident);
747 my (%seen_cols, @auto_colnames);
749 # compile a global list of column names, to be able to properly
750 # disambiguate unqualified column names (if at all possible)
751 for my $alias (keys %$alias2src) {
752 my $rsrc = $alias2src->{$alias};
753 for my $colname ($rsrc->columns) {
754 push @{$seen_cols{$colname}}, $alias;
755 push @auto_colnames, "$alias.$colname" unless $colnames;
761 grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols),
764 my (%return, $colinfos);
765 foreach my $col (@$colnames) {
766 my ($source_alias, $colname) = $col =~ m/^ (?: ([^\.]+) \. )? (.+) $/x;
768 # if the column was seen exactly once - we know which rsrc it came from
769 $source_alias ||= $seen_cols{$colname}[0]
770 if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1);
772 next unless $source_alias;
774 my $rsrc = $alias2src->{$source_alias}
779 ( $colinfos->{$source_alias} ||= $rsrc->columns_info )->{$colname}
781 $self->throw_exception(
782 "No such column '$colname' on source " . $rsrc->source_name
785 -result_source => $rsrc,
786 -source_alias => $source_alias,
787 -fq_colname => $col eq $colname ? "$source_alias.$col" : $col,
788 -colname => $colname,
791 $return{"$source_alias.$colname"} = $return{$col} if $col eq $colname;
797 # The DBIC relationship chaining implementation is pretty simple - every
798 # new related_relationship is pushed onto the {from} stack, and the {select}
799 # window simply slides further in. This means that when we count somewhere
800 # in the middle, we got to make sure that everything in the join chain is an
801 # actual inner join, otherwise the count will come back with unpredictable
802 # results (a resultset may be generated with _some_ rows regardless of if
803 # the relation which the $rs currently selects has rows or not). E.g.
804 # $artist_rs->cds->count - normally generates:
805 # SELECT COUNT( * ) FROM artist me LEFT JOIN cd cds ON cds.artist = me.artistid
806 # which actually returns the number of artists * (number of cds || 1)
808 # So what we do here is crawl {from}, determine if the current alias is at
809 # the top of the stack, and if not - make sure the chain is inner-joined down
812 sub _inner_join_to_node {
813 my ($self, $from, $alias) = @_;
815 # subqueries and other oddness are naturally not supported
821 ref $from->[0] ne 'HASH'
825 $from->[0]{-alias} eq $alias # this last bit means $alias is the head of $from - nothing to do
828 # find the current $alias in the $from structure
831 for my $j (@{$from}[1 .. $#$from]) {
832 if ($j->[0]{-alias} eq $alias) {
833 $switch_branch = $j->[0]{-join_path};
838 # something else went quite wrong
839 return $from unless $switch_branch;
841 # So it looks like we will have to switch some stuff around.
842 # local() is useless here as we will be leaving the scope
843 # anyway, and deep cloning is just too fucking expensive
844 # So replace the first hashref in the node arrayref manually
845 my @new_from = ($from->[0]);
846 my $sw_idx = { map { (values %$_), 1 } @$switch_branch }; #there's one k/v per join-path
848 for my $j (@{$from}[1 .. $#$from]) {
849 my $jalias = $j->[0]{-alias};
851 if ($sw_idx->{$jalias}) {
852 my %attrs = %{$j->[0]};
853 delete $attrs{-join_type};
867 sub _extract_order_criteria {
868 my ($self, $order_by, $sql_maker, $ident_only) = @_;
870 $sql_maker ||= $self->sql_maker;
872 my $order_dq = $sql_maker->converter->_order_by_to_dq($order_by);
875 while (is_Order($order_dq)) {
876 push @by, $order_dq->{by};
877 $order_dq = $order_dq->{from};
880 # delete local is 5.12+
881 local @{$sql_maker}{qw(quote_char renderer converter)};
882 delete @{$sql_maker}{qw(quote_char renderer converter)};
884 return map { [ $sql_maker->_render_dq($_) ] } do {
887 scan_dq_nodes({ DQ_IDENTIFIER ,=> sub { push @by_ident, $_[0] } }, @by);
895 sub _order_by_is_stable {
896 my ($self, $ident, $order_by, $where) = @_;
899 (map { $_->[0] } $self->_extract_order_criteria($order_by, undef, 1)),
900 $where ? @{$self->_extract_fixed_condition_columns($where)} :(),
903 my $colinfo = $self->_resolve_column_info($ident, \@cols);
905 return keys %$colinfo
906 ? $self->_columns_comprise_identifying_set( $colinfo, \@cols )
911 sub _columns_comprise_identifying_set {
912 my ($self, $colinfo, $columns) = @_;
915 $cols_per_src -> {$_->{-source_alias}} -> {$_->{-colname}} = $_
916 for grep { defined $_ } @{$colinfo}{@$columns};
918 for (values %$cols_per_src) {
919 my $src = (values %$_)[0]->{-result_source};
920 return 1 if $src->_identifying_column_set($_);
926 # this is almost identical to the above, except it accepts only
927 # a single rsrc, and will succeed only if the first portion of the order
929 # returns that portion as a colinfo hashref on success
930 sub _main_source_order_by_portion_is_stable {
931 my ($self, $main_rsrc, $order_by, $where) = @_;
933 die "Huh... I expect a blessed result_source..."
934 if ref($main_rsrc) eq 'ARRAY';
938 ( $self->_extract_order_criteria($order_by) )
940 return unless @ord_cols;
942 my $colinfos = $self->_resolve_column_info($main_rsrc);
944 for (0 .. $#ord_cols) {
946 ! $colinfos->{$ord_cols[$_]}
948 $colinfos->{$ord_cols[$_]}{-result_source} != $main_rsrc
955 # we just truncated it above
956 return unless @ord_cols;
958 my $order_portion_ci = { map {
959 $colinfos->{$_}{-colname} => $colinfos->{$_},
960 $colinfos->{$_}{-fq_colname} => $colinfos->{$_},
963 # since all we check here are the start of the order_by belonging to the
964 # top level $rsrc, a present identifying set will mean that the resultset
965 # is ordered by its leftmost table in a stable manner
967 # RV of _identifying_column_set contains unqualified names only
968 my $unqualified_idset = $main_rsrc->_identifying_column_set({
970 $self->_resolve_column_info(
971 $main_rsrc, $self->_extract_fixed_condition_columns($where)
978 my %unqualified_idcols_from_order = map {
979 $order_portion_ci->{$_} ? ( $_ => $order_portion_ci->{$_} ) : ()
980 } @$unqualified_idset;
982 # extra optimization - cut the order_by at the end of the identifying set
983 # (just in case the user was stupid and overlooked the obvious)
984 for my $i (0 .. $#ord_cols) {
985 my $col = $ord_cols[$i];
986 my $unqualified_colname = $order_portion_ci->{$col}{-colname};
987 $ret_info->{$col} = { %{$order_portion_ci->{$col}}, -idx_in_order_subset => $i };
988 delete $unqualified_idcols_from_order{$ret_info->{$col}{-colname}};
990 # we didn't reach the end of the identifying portion yet
991 return $ret_info unless keys %unqualified_idcols_from_order;
994 die 'How did we get here...';
997 # returns an arrayref of column names which *definitely* have some
998 # sort of non-nullable equality requested in the given condition
999 # specification. This is used to figure out if a resultset is
1000 # constrained to a column which is part of a unique constraint,
1001 # which in turn allows us to better predict how ordering will behave
1004 # this is a rudimentary, incomplete, and error-prone extractor
1005 # however this is OK - it is conservative, and if we can not find
1006 # something that is in fact there - the stack will recover gracefully
1007 # Also - DQ and the mst it rode in on will save us all RSN!!!
1008 sub _extract_fixed_condition_columns {
1009 my ($self, $where) = @_;
1011 if (ref($where) eq 'REF' and ref($$where) eq 'HASH') {
1013 my $fixed = DBIx::Class::ResultSource->_extract_fixed_values_for($$where);
1014 return [ keys %$fixed ];
1017 return unless ref $where eq 'HASH';
1020 for my $lhs (keys %$where) {
1021 if ($lhs =~ /^\-and$/i) {
1022 push @cols, ref $where->{$lhs} eq 'ARRAY'
1023 ? ( map { @{ $self->_extract_fixed_condition_columns($_) } } @{$where->{$lhs}} )
1024 : @{ $self->_extract_fixed_condition_columns($where->{$lhs}) }
1027 elsif ($lhs !~ /^\-/) {
1028 my $val = $where->{$lhs};
1030 push @cols, $lhs if (defined $val and (
1033 (ref $val eq 'HASH' and keys %$val == 1 and defined $val->{'='})