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';
22 # This code will remove non-selecting/non-restricting joins from
23 # {from} specs, aiding the RDBMS query optimizer
25 sub _prune_unused_joins {
26 my ($self, $attrs) = @_;
28 # only standard {from} specs are supported, and we could be disabled in general
29 return ($attrs->{from}, {}) unless (
30 ref $attrs->{from} eq 'ARRAY'
34 ref $attrs->{from}[0] eq 'HASH'
36 ref $attrs->{from}[1] eq 'ARRAY'
38 $self->_use_join_optimizer
41 my $orig_aliastypes = $self->_resolve_aliastypes_from_select_args($attrs);
43 my $new_aliastypes = { %$orig_aliastypes };
45 # we will be recreating this entirely
46 my @reclassify = 'joining';
48 # a grouped set will not be affected by amount of rows. Thus any
49 # purely multiplicator classifications can go
50 # (will be reintroduced below if needed by something else)
51 push @reclassify, qw(multiplying premultiplied)
52 if $attrs->{_force_prune_multiplying_joins} or $attrs->{group_by};
54 # nuke what will be recalculated
55 delete @{$new_aliastypes}{@reclassify};
57 my @newfrom = $attrs->{from}[0]; # FROM head is always present
59 # recalculate what we need once the multipliers are potentially gone
60 # ignore premultiplies, since they do not add any value to anything
62 for ( @{$new_aliastypes}{grep { $_ ne 'premultiplied' } keys %$new_aliastypes }) {
63 # add all requested aliases
64 $need_joins{$_} = 1 for keys %$_;
66 # add all their parents (as per joinpath which is an AoH { table => alias })
67 $need_joins{$_} = 1 for map { values %$_ } map { @{$_->{-parents}} } values %$_;
70 for my $j (@{$attrs->{from}}[1..$#{$attrs->{from}}]) {
71 push @newfrom, $j if (
72 (! defined $j->[0]{-alias}) # legacy crap
74 $need_joins{$j->[0]{-alias}}
78 # we have a new set of joiners - for everything we nuked pull the classification
79 # off the original stack
80 for my $ctype (@reclassify) {
81 $new_aliastypes->{$ctype} = { map
82 { $need_joins{$_} ? ( $_ => $orig_aliastypes->{$ctype}{$_} ) : () }
83 keys %{$orig_aliastypes->{$ctype}}
87 return ( \@newfrom, $new_aliastypes );
91 # This is the code producing joined subqueries like:
92 # SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
94 sub _adjust_select_args_for_complex_prefetch {
95 my ($self, $attrs) = @_;
97 $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute') unless (
98 ref $attrs->{from} eq 'ARRAY'
100 @{$attrs->{from}} > 1
102 ref $attrs->{from}[0] eq 'HASH'
104 ref $attrs->{from}[1] eq 'ARRAY'
107 my $root_alias = $attrs->{alias};
109 # generate inner/outer attribute lists, remove stuff that doesn't apply
110 my $outer_attrs = { %$attrs };
111 delete @{$outer_attrs}{qw(from bind rows offset group_by _grouped_by_distinct having)};
113 my $inner_attrs = { %$attrs };
114 delete @{$inner_attrs}{qw(for collapse select as _related_results_construction)};
116 # there is no point of ordering the insides if there is no limit
117 delete $inner_attrs->{order_by} if (
118 delete $inner_attrs->{_order_is_artificial}
120 ! $inner_attrs->{rows}
123 # generate the inner/outer select lists
124 # for inside we consider only stuff *not* brought in by the prefetch
125 # on the outside we substitute any function for its alias
126 $outer_attrs->{select} = [ @{$attrs->{select}} ];
128 my ($root_node, $root_node_offset);
130 for my $i (0 .. $#{$inner_attrs->{from}}) {
131 my $node = $inner_attrs->{from}[$i];
132 my $h = (ref $node eq 'HASH') ? $node
133 : (ref $node eq 'ARRAY' and ref $node->[0] eq 'HASH') ? $node->[0]
137 if ( ($h->{-alias}||'') eq $root_alias and $h->{-rsrc} ) {
139 $root_node_offset = $i;
144 $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
147 # use the heavy duty resolver to take care of aliased/nonaliased naming
148 my $colinfo = $self->_resolve_column_info($inner_attrs->{from});
149 my $selected_root_columns;
151 for my $i (0 .. $#{$outer_attrs->{select}}) {
152 my $sel = $outer_attrs->{select}->[$i];
155 $colinfo->{$sel} and $colinfo->{$sel}{-source_alias} ne $root_alias
158 if (ref $sel eq 'HASH' ) {
159 $sel->{-as} ||= $attrs->{as}[$i];
160 $outer_attrs->{select}->[$i] = join ('.', $root_alias, ($sel->{-as} || "inner_column_$i") );
162 elsif (! ref $sel and my $ci = $colinfo->{$sel}) {
163 $selected_root_columns->{$ci->{-colname}} = 1;
166 push @{$inner_attrs->{select}}, $sel;
168 push @{$inner_attrs->{as}}, $attrs->{as}[$i];
171 # We will need to fetch all native columns in the inner subquery, which may
172 # be a part of an *outer* join condition, or an order_by (which needs to be
173 # preserved outside), or wheres. In other words everything but the inner
175 # We can not just fetch everything because a potential has_many restricting
176 # join collapse *will not work* on heavy data types.
177 my $connecting_aliastypes = $self->_resolve_aliastypes_from_select_args({
182 for (sort map { keys %{$_->{-seen_columns}||{}} } map { values %$_ } values %$connecting_aliastypes) {
183 my $ci = $colinfo->{$_} or next;
185 $ci->{-source_alias} eq $root_alias
187 ! $selected_root_columns->{$ci->{-colname}}++
189 # adding it to both to keep limits not supporting dark selectors happy
190 push @{$inner_attrs->{select}}, $ci->{-fq_colname};
191 push @{$inner_attrs->{as}}, $ci->{-fq_colname};
195 # construct the inner {from} and lock it in a subquery
196 # we need to prune first, because this will determine if we need a group_by below
197 # throw away all non-selecting, non-restricting multijoins
198 # (since we def. do not care about multiplication of the contents of the subquery)
199 my $inner_subq = do {
201 # must use it here regardless of user requests (vastly gentler on optimizer)
202 local $self->{_use_join_optimizer} = 1;
204 # throw away multijoins since we def. do not care about those inside the subquery
205 ($inner_attrs->{from}, my $inner_aliastypes) = $self->_prune_unused_joins ({
206 %$inner_attrs, _force_prune_multiplying_joins => 1
209 # uh-oh a multiplier (which is not us) left in, this is a problem for limits
210 # we will need to add a group_by to collapse the resultset for proper counts
212 grep { $_ ne $root_alias } keys %{ $inner_aliastypes->{multiplying} || {} }
214 # if there are user-supplied groups - assume user knows wtf they are up to
215 ( ! $inner_aliastypes->{grouping} or $inner_attrs->{_grouped_by_distinct} )
218 my $cur_sel = { map { $_ => 1 } @{$inner_attrs->{select}} };
220 # *possibly* supplement the main selection with pks if not already
221 # there, as they will have to be a part of the group_by to collapse
223 my $inner_select_with_extras;
224 my @pks = map { "$root_alias.$_" } $root_node->{-rsrc}->primary_columns
225 or $self->throw_exception( sprintf
226 'Unable to perform complex limited prefetch off %s without declared primary key',
227 $root_node->{-rsrc}->source_name,
230 push @{ $inner_select_with_extras ||= [ @{$inner_attrs->{select}} ] }, $col
231 unless $cur_sel->{$col}++;
234 ($inner_attrs->{group_by}, $inner_attrs->{order_by}) = $self->_group_over_selection({
236 $inner_select_with_extras ? ( select => $inner_select_with_extras ) : (),
237 _aliastypes => $inner_aliastypes,
241 # we already optimized $inner_attrs->{from} above
242 # and already local()ized
243 $self->{_use_join_optimizer} = 0;
245 # generate the subquery
246 $self->_select_args_to_query (
247 @{$inner_attrs}{qw(from select where)},
252 # Generate the outer from - this is relatively easy (really just replace
253 # the join slot with the subquery), with a major caveat - we can not
254 # join anything that is non-selecting (not part of the prefetch), but at
255 # the same time is a multi-type relationship, as it will explode the result.
257 # There are two possibilities here
258 # - either the join is non-restricting, in which case we simply throw it away
259 # - it is part of the restrictions, in which case we need to collapse the outer
260 # result by tackling yet another group_by to the outside of the query
262 # work on a shallow copy
263 my @orig_from = @{$attrs->{from}};
266 $outer_attrs->{from} = \ my @outer_from;
268 # we may not be the head
269 if ($root_node_offset) {
270 # first generate the outer_from, up to the substitution point
271 @outer_from = splice @orig_from, 0, $root_node_offset;
273 # substitute the subq at the right spot
276 -alias => $root_alias,
277 -rsrc => $root_node->{-rsrc},
278 $root_alias => $inner_subq,
280 # preserve attrs from what is now the head of the from after the splice
281 @{$orig_from[0]}[1 .. $#{$orig_from[0]}],
286 -alias => $root_alias,
287 -rsrc => $root_node->{-rsrc},
288 $root_alias => $inner_subq,
292 shift @orig_from; # what we just replaced above
294 # scan the *remaining* from spec against different attributes, and see which joins are needed
296 my $outer_aliastypes = $outer_attrs->{_aliastypes} =
297 $self->_resolve_aliastypes_from_select_args({ %$outer_attrs, from => \@orig_from });
300 my ($outer_select_chain, @outer_nonselecting_chains) = map { +{
301 map { $_ => 1 } map { values %$_} map { @{$_->{-parents}} } values %{ $outer_aliastypes->{$_} || {} }
302 } } qw/selecting restricting grouping ordering/;
304 # see what's left - throw away if not selecting/restricting
305 my $may_need_outer_group_by;
306 while (my $j = shift @orig_from) {
307 my $alias = $j->[0]{-alias};
310 $outer_select_chain->{$alias}
314 elsif (first { $_->{$alias} } @outer_nonselecting_chains ) {
315 push @outer_from, $j;
316 $may_need_outer_group_by ||= $outer_aliastypes->{multiplying}{$alias} ? 1 : 0;
320 # also throw in a synthetic group_by if a non-selecting multiplier,
321 # to guard against cross-join explosions
322 # the logic is somewhat fragile, but relies on the idea that if a user supplied
323 # a group by on their own - they know what they were doing
324 if ( $may_need_outer_group_by and $attrs->{_grouped_by_distinct} ) {
325 ($outer_attrs->{group_by}, $outer_attrs->{order_by}) = $self->_group_over_selection ({
327 from => \@outer_from,
331 # This is totally horrific - the {where} ends up in both the inner and outer query
332 # Unfortunately not much can be done until SQLA2 introspection arrives, and even
333 # then if where conditions apply to the *right* side of the prefetch, you may have
334 # to both filter the inner select (e.g. to apply a limit) and then have to re-filter
335 # the outer select to exclude joins you didn't want in the first place
337 # OTOH it can be seen as a plus: <ash> (notes that this query would make a DBA cry ;)
342 # I KNOW THIS SUCKS! GET SQLA2 OUT THE DOOR SO THIS CAN DIE!
344 # Due to a lack of SQLA2 we fall back to crude scans of all the
345 # select/where/order/group attributes, in order to determine what
346 # aliases are needed to fulfill the query. This information is used
347 # throughout the code to prune unnecessary JOINs from the queries
348 # in an attempt to reduce the execution time.
349 # Although the method is pretty horrific, the worst thing that can
350 # happen is for it to fail due to some scalar SQL, which in turn will
351 # result in a vocal exception.
352 sub _resolve_aliastypes_from_select_args {
353 my ( $self, $attrs ) = @_;
355 $self->throw_exception ('Unable to analyze custom {from}')
356 if ref $attrs->{from} ne 'ARRAY';
358 # what we will return
361 # see what aliases are there to work with
362 # and record who is a multiplier and who is premultiplied
364 for my $node (@{$attrs->{from}}) {
367 $j = $j->[0] if ref $j eq 'ARRAY';
368 my $al = $j->{-alias}
371 $alias_list->{$al} = $j;
373 $aliases_by_type->{multiplying}{$al} ||= { -parents => $j->{-join_path}||[] }
374 # not array == {from} head == can't be multiplying
375 if ref($node) eq 'ARRAY' and ! $j->{-is_single};
377 $aliases_by_type->{premultiplied}{$al} ||= { -parents => $j->{-join_path}||[] }
378 # parts of the path that are not us but are multiplying
379 if grep { $aliases_by_type->{multiplying}{$_} }
382 @{ $j->{-join_path}||[] }
385 # get a column to source/alias map (including unambiguous unqualified ones)
386 my $colinfo = $self->_resolve_column_info ($attrs->{from});
388 # set up a botched SQLA
389 my $sql_maker = $self->sql_maker;
391 # these are throw away results, do not pollute the bind stack
392 local $sql_maker->{select_bind};
393 local $sql_maker->{where_bind};
394 local $sql_maker->{group_bind};
395 local $sql_maker->{having_bind};
396 local $sql_maker->{from_bind};
398 # we can't scan properly without any quoting (\b doesn't cut it
399 # everywhere), so unless there is proper quoting set - use our
400 # own weird impossible character.
401 # Also in the case of no quoting, we need to explicitly disable
402 # name_sep, otherwise sorry nasty legacy syntax like
403 # { 'count(foo.id)' => { '>' => 3 } } will stop working >:(
404 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
405 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
407 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
408 $sql_maker->{quote_char} = ["\x00", "\xFF"];
409 # if we don't unset it we screw up retarded but unfortunately working
410 # 'MAX(foo.bar)' => { '>', 3 }
411 $sql_maker->{name_sep} = '';
414 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
416 # generate sql chunks
419 $sql_maker->_recurse_where ($attrs->{where}),
420 $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} }),
423 $sql_maker->_parse_rs_attrs ({ group_by => $attrs->{group_by} }),
426 $sql_maker->_recurse_from (
427 ref $attrs->{from}[0] eq 'ARRAY' ? $attrs->{from}[0][0] : $attrs->{from}[0],
428 @{$attrs->{from}}[1 .. $#{$attrs->{from}}],
432 map { $sql_maker->_recurse_fields($_) } @{$attrs->{select}},
435 map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker),
439 # throw away empty chunks and all 2-value arrayrefs: the thinking is that these are
440 # bind value specs left in by the sloppy renderer above. It is ok to do this
441 # at this point, since we are going to end up rewriting this crap anyway
442 for my $v (values %$to_scan) {
451 ( @$_ == 0 or @$_ == 2 )
456 require Data::Dumper::Concise;
457 $self->throw_exception("Unexpected ref in scan-plan: " . Data::Dumper::Concise::Dumper($v) );
466 # kill all selectors which look like a proper subquery
467 # this is a sucky heuristic *BUT* - if we get it wrong the query will simply
468 # fail to run, so we are relatively safe
469 $to_scan->{selecting} = [ grep {
470 $_ !~ / \A \s* \( \s* SELECT \s+ .+? \s+ FROM \s+ .+? \) \s* \z /xsi
471 } @{ $to_scan->{selecting} || [] } ];
473 # first see if we have any exact matches (qualified or unqualified)
474 for my $type (keys %$to_scan) {
475 for my $piece (@{$to_scan->{$type}}) {
476 if ($colinfo->{$piece} and my $alias = $colinfo->{$piece}{-source_alias}) {
477 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
478 $aliases_by_type->{$type}{$alias}{-seen_columns}{$colinfo->{$piece}{-fq_colname}} = $piece;
483 # now loop through all fully qualified columns and get the corresponding
484 # alias (should work even if they are in scalarrefs)
485 for my $alias (keys %$alias_list) {
487 $lquote $alias $rquote $sep (?: $lquote ([^$rquote]+) $rquote )?
489 \b $alias \. ([^\s\)\($rquote]+)?
492 for my $type (keys %$to_scan) {
493 for my $piece (@{$to_scan->{$type}}) {
494 if (my @matches = $piece =~ /$al_re/g) {
495 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
496 $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = "$alias.$_"
497 for grep { defined $_ } @matches;
503 # now loop through unqualified column names, and try to locate them within
505 for my $col (keys %$colinfo) {
506 next if $col =~ / \. /x; # if column is qualified it was caught by the above
508 my $col_re = qr/ $lquote ($col) $rquote /x;
510 for my $type (keys %$to_scan) {
511 for my $piece (@{$to_scan->{$type}}) {
512 if ( my @matches = $piece =~ /$col_re/g) {
513 my $alias = $colinfo->{$col}{-source_alias};
514 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
515 $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = $_
516 for grep { defined $_ } @matches;
522 # Add any non-left joins to the restriction list (such joins are indeed restrictions)
523 for my $j (values %$alias_list) {
524 my $alias = $j->{-alias} or next;
525 $aliases_by_type->{restricting}{$alias} ||= { -parents => $j->{-join_path}||[] } if (
526 (not $j->{-join_type})
528 ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
532 for (keys %$aliases_by_type) {
533 delete $aliases_by_type->{$_} unless keys %{$aliases_by_type->{$_}};
536 return $aliases_by_type;
539 # This is the engine behind { distinct => 1 } and the general
540 # complex prefetch grouper
541 sub _group_over_selection {
542 my ($self, $attrs) = @_;
544 my $colinfos = $self->_resolve_column_info ($attrs->{from});
546 my (@group_by, %group_index);
548 # the logic is: if it is a { func => val } we assume an aggregate,
549 # otherwise if \'...' or \[...] we assume the user knows what is
550 # going on thus group over it
551 for (@{$attrs->{select}}) {
552 if (! ref($_) or ref ($_) ne 'HASH' ) {
555 if ($colinfos->{$_} and $_ !~ /\./ ) {
556 # add a fully qualified version as well
557 $group_index{"$colinfos->{$_}{-source_alias}.$_"}++;
562 my @order_by = $self->_extract_order_criteria($attrs->{order_by})
563 or return (\@group_by, $attrs->{order_by});
565 # add any order_by parts that are not already present in the group_by
566 # to maintain SQL cross-compatibility and general sanity
568 # also in case the original selection is *not* unique, or in case part
569 # of the ORDER BY refers to a multiplier - we will need to replace the
570 # skipped order_by elements with their MIN/MAX equivalents as to maintain
571 # the proper overall order without polluting the group criteria (and
572 # possibly changing the outcome entirely)
574 my ($leftovers, $sql_maker, @new_order_by, $order_chunks, $aliastypes);
576 my $group_already_unique = $self->_columns_comprise_identifying_set($colinfos, \@group_by);
578 for my $o_idx (0 .. $#order_by) {
580 # if the chunk is already a min/max function - there is nothing left to touch
581 next if $order_by[$o_idx][0] =~ /^ (?: min | max ) \s* \( .+ \) $/ix;
583 # only consider real columns (for functions the user got to do an explicit group_by)
586 @{$order_by[$o_idx]} != 1
588 # only declare an unknown *plain* identifier as "leftover" if we are called with
589 # aliastypes to examine. If there are none - we are still in _resolve_attrs, and
590 # can just assume the user knows what they want
591 ( ! ( $chunk_ci = $colinfos->{$order_by[$o_idx][0]} ) and $attrs->{_aliastypes} )
593 push @$leftovers, $order_by[$o_idx][0];
596 next unless $chunk_ci;
598 # no duplication of group criteria
599 next if $group_index{$chunk_ci->{-fq_colname}};
602 $attrs->{_aliastypes}
604 $self->_resolve_aliastypes_from_select_args({
605 from => $attrs->{from},
606 order_by => $attrs->{order_by},
608 ) if $group_already_unique;
610 # check that we are not ordering by a multiplier (if a check is requested at all)
612 $group_already_unique
614 ! $aliastypes->{multiplying}{$chunk_ci->{-source_alias}}
616 ! $aliastypes->{premultiplied}{$chunk_ci->{-source_alias}}
618 push @group_by, $chunk_ci->{-fq_colname};
619 $group_index{$chunk_ci->{-fq_colname}}++
622 # We need to order by external columns without adding them to the group
623 # (eiehter a non-unique selection, or a multi-external)
625 # This doesn't really make sense in SQL, however from DBICs point
626 # of view is rather valid (e.g. order the leftmost objects by whatever
627 # criteria and get the offset/rows many). There is a way around
628 # this however in SQL - we simply tae the direction of each piece
629 # of the external order and convert them to MIN(X) for ASC or MAX(X)
630 # for DESC, and group_by the root columns. The end result should be
631 # exactly what we expect
633 # FIXME - this code is a joke, will need to be completely rewritten in
634 # the DQ branch. But I need to push a POC here, otherwise the
635 # pesky tests won't pass
636 # wrap any part of the order_by that "responds" to an ordering alias
638 $sql_maker ||= $self->sql_maker;
640 map { ref $_ eq 'ARRAY' ? $_ : [ $_ ] } $sql_maker->_order_by_chunks($attrs->{order_by})
643 my ($chunk, $is_desc) = $sql_maker->_split_order_chunk($order_chunks->[$o_idx][0]);
645 $new_order_by[$o_idx] = \[
646 sprintf( '%s( %s )%s',
647 ($is_desc ? 'MAX' : 'MIN'),
649 ($is_desc ? ' DESC' : ''),
651 @ {$order_chunks->[$o_idx]} [ 1 .. $#{$order_chunks->[$o_idx]} ]
656 $self->throw_exception ( sprintf
657 'A required group_by clause could not be constructed automatically due to a complex '
658 . 'order_by criteria (%s). Either order_by columns only (no functions) or construct a suitable '
659 . 'group_by by hand',
660 join ', ', map { "'$_'" } @$leftovers,
663 # recreate the untouched order parts
665 $new_order_by[$_] ||= \ $order_chunks->[$_] for ( 0 .. $#$order_chunks );
670 (@new_order_by ? \@new_order_by : $attrs->{order_by} ), # same ref as original == unchanged
674 sub _resolve_ident_sources {
675 my ($self, $ident) = @_;
677 my $alias2source = {};
679 # the reason this is so contrived is that $ident may be a {from}
680 # structure, specifying multiple tables to join
681 if ( blessed $ident && $ident->isa("DBIx::Class::ResultSource") ) {
682 # this is compat mode for insert/update/delete which do not deal with aliases
683 $alias2source->{me} = $ident;
685 elsif (ref $ident eq 'ARRAY') {
689 if (ref $_ eq 'HASH') {
692 if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') {
696 $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-rsrc}
697 if ($tabinfo->{-rsrc});
701 return $alias2source;
704 # Takes $ident, \@column_names
706 # returns { $column_name => \%column_info, ... }
707 # also note: this adds -result_source => $rsrc to the column info
709 # If no columns_names are supplied returns info about *all* columns
711 sub _resolve_column_info {
712 my ($self, $ident, $colnames) = @_;
713 my $alias2src = $self->_resolve_ident_sources($ident);
715 my (%seen_cols, @auto_colnames);
717 # compile a global list of column names, to be able to properly
718 # disambiguate unqualified column names (if at all possible)
719 for my $alias (keys %$alias2src) {
720 my $rsrc = $alias2src->{$alias};
721 for my $colname ($rsrc->columns) {
722 push @{$seen_cols{$colname}}, $alias;
723 push @auto_colnames, "$alias.$colname" unless $colnames;
729 grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols),
732 my (%return, $colinfos);
733 foreach my $col (@$colnames) {
734 my ($source_alias, $colname) = $col =~ m/^ (?: ([^\.]+) \. )? (.+) $/x;
736 # if the column was seen exactly once - we know which rsrc it came from
737 $source_alias ||= $seen_cols{$colname}[0]
738 if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1);
740 next unless $source_alias;
742 my $rsrc = $alias2src->{$source_alias}
747 ( $colinfos->{$source_alias} ||= $rsrc->columns_info )->{$colname}
749 $self->throw_exception(
750 "No such column '$colname' on source " . $rsrc->source_name
753 -result_source => $rsrc,
754 -source_alias => $source_alias,
755 -fq_colname => $col eq $colname ? "$source_alias.$col" : $col,
756 -colname => $colname,
759 $return{"$source_alias.$colname"} = $return{$col} if $col eq $colname;
765 # The DBIC relationship chaining implementation is pretty simple - every
766 # new related_relationship is pushed onto the {from} stack, and the {select}
767 # window simply slides further in. This means that when we count somewhere
768 # in the middle, we got to make sure that everything in the join chain is an
769 # actual inner join, otherwise the count will come back with unpredictable
770 # results (a resultset may be generated with _some_ rows regardless of if
771 # the relation which the $rs currently selects has rows or not). E.g.
772 # $artist_rs->cds->count - normally generates:
773 # SELECT COUNT( * ) FROM artist me LEFT JOIN cd cds ON cds.artist = me.artistid
774 # which actually returns the number of artists * (number of cds || 1)
776 # So what we do here is crawl {from}, determine if the current alias is at
777 # the top of the stack, and if not - make sure the chain is inner-joined down
780 sub _inner_join_to_node {
781 my ($self, $from, $alias) = @_;
783 # subqueries and other oddness are naturally not supported
789 ref $from->[0] ne 'HASH'
793 $from->[0]{-alias} eq $alias # this last bit means $alias is the head of $from - nothing to do
796 # find the current $alias in the $from structure
799 for my $j (@{$from}[1 .. $#$from]) {
800 if ($j->[0]{-alias} eq $alias) {
801 $switch_branch = $j->[0]{-join_path};
806 # something else went quite wrong
807 return $from unless $switch_branch;
809 # So it looks like we will have to switch some stuff around.
810 # local() is useless here as we will be leaving the scope
811 # anyway, and deep cloning is just too fucking expensive
812 # So replace the first hashref in the node arrayref manually
813 my @new_from = ($from->[0]);
814 my $sw_idx = { map { (values %$_), 1 } @$switch_branch }; #there's one k/v per join-path
816 for my $j (@{$from}[1 .. $#$from]) {
817 my $jalias = $j->[0]{-alias};
819 if ($sw_idx->{$jalias}) {
820 my %attrs = %{$j->[0]};
821 delete $attrs{-join_type};
835 sub _extract_order_criteria {
836 my ($self, $order_by, $sql_maker) = @_;
839 my ($sql_maker, $order_by, $orig_quote_chars) = @_;
841 return scalar $sql_maker->_order_by_chunks ($order_by)
844 my ($lq, $rq, $sep) = map { quotemeta($_) } (
845 ($orig_quote_chars ? @$orig_quote_chars : $sql_maker->_quote_chars),
850 for ($sql_maker->_order_by_chunks ($order_by) ) {
851 my $chunk = ref $_ ? [ @$_ ] : [ $_ ];
852 ($chunk->[0]) = $sql_maker->_split_order_chunk($chunk->[0]);
854 # order criteria may have come back pre-quoted (literals and whatnot)
855 # this is fragile, but the best we can currently do
856 $chunk->[0] =~ s/^ $lq (.+?) $rq $sep $lq (.+?) $rq $/"$1.$2"/xe
857 or $chunk->[0] =~ s/^ $lq (.+) $rq $/$1/x;
859 push @chunks, $chunk;
866 return $parser->($sql_maker, $order_by);
869 $sql_maker = $self->sql_maker;
871 # pass these in to deal with literals coming from
872 # the user or the deep guts of prefetch
873 my $orig_quote_chars = [$sql_maker->_quote_chars];
875 local $sql_maker->{quote_char};
876 return $parser->($sql_maker, $order_by, $orig_quote_chars);
880 sub _order_by_is_stable {
881 my ($self, $ident, $order_by, $where) = @_;
884 (map { $_->[0] } $self->_extract_order_criteria($order_by)),
885 $where ? @{$self->_extract_fixed_condition_columns($where)} :(),
888 my $colinfo = $self->_resolve_column_info($ident, \@cols);
890 return keys %$colinfo
891 ? $self->_columns_comprise_identifying_set( $colinfo, \@cols )
896 sub _columns_comprise_identifying_set {
897 my ($self, $colinfo, $columns) = @_;
900 $cols_per_src -> {$_->{-source_alias}} -> {$_->{-colname}} = $_
901 for grep { defined $_ } @{$colinfo}{@$columns};
903 for (values %$cols_per_src) {
904 my $src = (values %$_)[0]->{-result_source};
905 return 1 if $src->_identifying_column_set($_);
911 # this is almost identical to the above, except it accepts only
912 # a single rsrc, and will succeed only if the first portion of the order
914 # returns that portion as a colinfo hashref on success
915 sub _main_source_order_by_portion_is_stable {
916 my ($self, $main_rsrc, $order_by, $where) = @_;
918 die "Huh... I expect a blessed result_source..."
919 if ref($main_rsrc) eq 'ARRAY';
923 ( $self->_extract_order_criteria($order_by) )
925 return unless @ord_cols;
927 my $colinfos = $self->_resolve_column_info($main_rsrc);
929 for (0 .. $#ord_cols) {
931 ! $colinfos->{$ord_cols[$_]}
933 $colinfos->{$ord_cols[$_]}{-result_source} != $main_rsrc
940 # we just truncated it above
941 return unless @ord_cols;
943 my $order_portion_ci = { map {
944 $colinfos->{$_}{-colname} => $colinfos->{$_},
945 $colinfos->{$_}{-fq_colname} => $colinfos->{$_},
948 # since all we check here are the start of the order_by belonging to the
949 # top level $rsrc, a present identifying set will mean that the resultset
950 # is ordered by its leftmost table in a stable manner
952 # RV of _identifying_column_set contains unqualified names only
953 my $unqualified_idset = $main_rsrc->_identifying_column_set({
955 $self->_resolve_column_info(
956 $main_rsrc, $self->_extract_fixed_condition_columns($where)
963 my %unqualified_idcols_from_order = map {
964 $order_portion_ci->{$_} ? ( $_ => $order_portion_ci->{$_} ) : ()
965 } @$unqualified_idset;
967 # extra optimization - cut the order_by at the end of the identifying set
968 # (just in case the user was stupid and overlooked the obvious)
969 for my $i (0 .. $#ord_cols) {
970 my $col = $ord_cols[$i];
971 my $unqualified_colname = $order_portion_ci->{$col}{-colname};
972 $ret_info->{$col} = { %{$order_portion_ci->{$col}}, -idx_in_order_subset => $i };
973 delete $unqualified_idcols_from_order{$ret_info->{$col}{-colname}};
975 # we didn't reach the end of the identifying portion yet
976 return $ret_info unless keys %unqualified_idcols_from_order;
979 die 'How did we get here...';
982 # returns an arrayref of column names which *definitely* have some
983 # sort of non-nullable equality requested in the given condition
984 # specification. This is used to figure out if a resultset is
985 # constrained to a column which is part of a unique constraint,
986 # which in turn allows us to better predict how ordering will behave
989 # this is a rudimentary, incomplete, and error-prone extractor
990 # however this is OK - it is conservative, and if we can not find
991 # something that is in fact there - the stack will recover gracefully
992 # Also - DQ and the mst it rode in on will save us all RSN!!!
993 sub _extract_fixed_condition_columns {
994 my ($self, $where) = @_;
996 return unless ref $where eq 'HASH';
999 for my $lhs (keys %$where) {
1000 if ($lhs =~ /^\-and$/i) {
1001 push @cols, ref $where->{$lhs} eq 'ARRAY'
1002 ? ( map { @{ $self->_extract_fixed_condition_columns($_) } } @{$where->{$lhs}} )
1003 : @{ $self->_extract_fixed_condition_columns($where->{$lhs}) }
1006 elsif ($lhs !~ /^\-/) {
1007 my $val = $where->{$lhs};
1009 push @cols, $lhs if (defined $val and (
1012 (ref $val eq 'HASH' and keys %$val == 1 and defined $val->{'='})