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 $sql_maker->_recurse_fields ($attrs->{select}),
435 map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker),
439 # throw away empty chunks
440 $_ = [ map { $_ || () } @$_ ] for values %$to_scan;
442 # first see if we have any exact matches (qualified or unqualified)
443 for my $type (keys %$to_scan) {
444 for my $piece (@{$to_scan->{$type}}) {
445 if ($colinfo->{$piece} and my $alias = $colinfo->{$piece}{-source_alias}) {
446 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
447 $aliases_by_type->{$type}{$alias}{-seen_columns}{$colinfo->{$piece}{-fq_colname}} = $piece;
452 # now loop through all fully qualified columns and get the corresponding
453 # alias (should work even if they are in scalarrefs)
454 for my $alias (keys %$alias_list) {
456 $lquote $alias $rquote $sep (?: $lquote ([^$rquote]+) $rquote )?
458 \b $alias \. ([^\s\)\($rquote]+)?
461 for my $type (keys %$to_scan) {
462 for my $piece (@{$to_scan->{$type}}) {
463 if (my @matches = $piece =~ /$al_re/g) {
464 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
465 $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = "$alias.$_"
466 for grep { defined $_ } @matches;
472 # now loop through unqualified column names, and try to locate them within
474 for my $col (keys %$colinfo) {
475 next if $col =~ / \. /x; # if column is qualified it was caught by the above
477 my $col_re = qr/ $lquote ($col) $rquote /x;
479 for my $type (keys %$to_scan) {
480 for my $piece (@{$to_scan->{$type}}) {
481 if ( my @matches = $piece =~ /$col_re/g) {
482 my $alias = $colinfo->{$col}{-source_alias};
483 $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] };
484 $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = $_
485 for grep { defined $_ } @matches;
491 # Add any non-left joins to the restriction list (such joins are indeed restrictions)
492 for my $j (values %$alias_list) {
493 my $alias = $j->{-alias} or next;
494 $aliases_by_type->{restricting}{$alias} ||= { -parents => $j->{-join_path}||[] } if (
495 (not $j->{-join_type})
497 ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
501 for (keys %$aliases_by_type) {
502 delete $aliases_by_type->{$_} unless keys %{$aliases_by_type->{$_}};
505 return $aliases_by_type;
508 # This is the engine behind { distinct => 1 } and the general
509 # complex prefetch grouper
510 sub _group_over_selection {
511 my ($self, $attrs) = @_;
513 my $colinfos = $self->_resolve_column_info ($attrs->{from});
515 my (@group_by, %group_index);
517 # the logic is: if it is a { func => val } we assume an aggregate,
518 # otherwise if \'...' or \[...] we assume the user knows what is
519 # going on thus group over it
520 for (@{$attrs->{select}}) {
521 if (! ref($_) or ref ($_) ne 'HASH' ) {
524 if ($colinfos->{$_} and $_ !~ /\./ ) {
525 # add a fully qualified version as well
526 $group_index{"$colinfos->{$_}{-source_alias}.$_"}++;
531 my @order_by = $self->_extract_order_criteria($attrs->{order_by})
532 or return (\@group_by, $attrs->{order_by});
534 # add any order_by parts that are not already present in the group_by
535 # to maintain SQL cross-compatibility and general sanity
537 # also in case the original selection is *not* unique, or in case part
538 # of the ORDER BY refers to a multiplier - we will need to replace the
539 # skipped order_by elements with their MIN/MAX equivalents as to maintain
540 # the proper overall order without polluting the group criteria (and
541 # possibly changing the outcome entirely)
543 my ($leftovers, $sql_maker, @new_order_by, $order_chunks, $aliastypes);
545 my $group_already_unique = $self->_columns_comprise_identifying_set($colinfos, \@group_by);
547 for my $o_idx (0 .. $#order_by) {
549 # if the chunk is already a min/max function - there is nothing left to touch
550 next if $order_by[$o_idx][0] =~ /^ (?: min | max ) \s* \( .+ \) $/ix;
552 # only consider real columns (for functions the user got to do an explicit group_by)
555 @{$order_by[$o_idx]} != 1
557 # only declare an unknown *plain* identifier as "leftover" if we are called with
558 # aliastypes to examine. If there are none - we are still in _resolve_attrs, and
559 # can just assume the user knows what they want
560 ( ! ( $chunk_ci = $colinfos->{$order_by[$o_idx][0]} ) and $attrs->{_aliastypes} )
562 push @$leftovers, $order_by[$o_idx][0];
565 next unless $chunk_ci;
567 # no duplication of group criteria
568 next if $group_index{$chunk_ci->{-fq_colname}};
571 $attrs->{_aliastypes}
573 $self->_resolve_aliastypes_from_select_args({
574 from => $attrs->{from},
575 order_by => $attrs->{order_by},
577 ) if $group_already_unique;
579 # check that we are not ordering by a multiplier (if a check is requested at all)
581 $group_already_unique
583 ! $aliastypes->{multiplying}{$chunk_ci->{-source_alias}}
585 ! $aliastypes->{premultiplied}{$chunk_ci->{-source_alias}}
587 push @group_by, $chunk_ci->{-fq_colname};
588 $group_index{$chunk_ci->{-fq_colname}}++
591 # We need to order by external columns without adding them to the group
592 # (eiehter a non-unique selection, or a multi-external)
594 # This doesn't really make sense in SQL, however from DBICs point
595 # of view is rather valid (e.g. order the leftmost objects by whatever
596 # criteria and get the offset/rows many). There is a way around
597 # this however in SQL - we simply tae the direction of each piece
598 # of the external order and convert them to MIN(X) for ASC or MAX(X)
599 # for DESC, and group_by the root columns. The end result should be
600 # exactly what we expect
602 # FIXME - this code is a joke, will need to be completely rewritten in
603 # the DQ branch. But I need to push a POC here, otherwise the
604 # pesky tests won't pass
605 # wrap any part of the order_by that "responds" to an ordering alias
607 $sql_maker ||= $self->sql_maker;
609 map { ref $_ eq 'ARRAY' ? $_ : [ $_ ] } $sql_maker->_order_by_chunks($attrs->{order_by})
612 my ($chunk, $is_desc) = $sql_maker->_split_order_chunk($order_chunks->[$o_idx][0]);
614 $new_order_by[$o_idx] = \[
615 sprintf( '%s( %s )%s',
616 ($is_desc ? 'MAX' : 'MIN'),
618 ($is_desc ? ' DESC' : ''),
620 @ {$order_chunks->[$o_idx]} [ 1 .. $#{$order_chunks->[$o_idx]} ]
625 $self->throw_exception ( sprintf
626 'A required group_by clause could not be constructed automatically due to a complex '
627 . 'order_by criteria (%s). Either order_by columns only (no functions) or construct a suitable '
628 . 'group_by by hand',
629 join ', ', map { "'$_'" } @$leftovers,
632 # recreate the untouched order parts
634 $new_order_by[$_] ||= \ $order_chunks->[$_] for ( 0 .. $#$order_chunks );
639 (@new_order_by ? \@new_order_by : $attrs->{order_by} ), # same ref as original == unchanged
643 sub _resolve_ident_sources {
644 my ($self, $ident) = @_;
646 my $alias2source = {};
648 # the reason this is so contrived is that $ident may be a {from}
649 # structure, specifying multiple tables to join
650 if ( blessed $ident && $ident->isa("DBIx::Class::ResultSource") ) {
651 # this is compat mode for insert/update/delete which do not deal with aliases
652 $alias2source->{me} = $ident;
654 elsif (ref $ident eq 'ARRAY') {
658 if (ref $_ eq 'HASH') {
661 if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') {
665 $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-rsrc}
666 if ($tabinfo->{-rsrc});
670 return $alias2source;
673 # Takes $ident, \@column_names
675 # returns { $column_name => \%column_info, ... }
676 # also note: this adds -result_source => $rsrc to the column info
678 # If no columns_names are supplied returns info about *all* columns
680 sub _resolve_column_info {
681 my ($self, $ident, $colnames) = @_;
682 my $alias2src = $self->_resolve_ident_sources($ident);
684 my (%seen_cols, @auto_colnames);
686 # compile a global list of column names, to be able to properly
687 # disambiguate unqualified column names (if at all possible)
688 for my $alias (keys %$alias2src) {
689 my $rsrc = $alias2src->{$alias};
690 for my $colname ($rsrc->columns) {
691 push @{$seen_cols{$colname}}, $alias;
692 push @auto_colnames, "$alias.$colname" unless $colnames;
698 grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols),
701 my (%return, $colinfos);
702 foreach my $col (@$colnames) {
703 my ($source_alias, $colname) = $col =~ m/^ (?: ([^\.]+) \. )? (.+) $/x;
705 # if the column was seen exactly once - we know which rsrc it came from
706 $source_alias ||= $seen_cols{$colname}[0]
707 if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1);
709 next unless $source_alias;
711 my $rsrc = $alias2src->{$source_alias}
716 ( $colinfos->{$source_alias} ||= $rsrc->columns_info )->{$colname}
718 $self->throw_exception(
719 "No such column '$colname' on source " . $rsrc->source_name
722 -result_source => $rsrc,
723 -source_alias => $source_alias,
724 -fq_colname => $col eq $colname ? "$source_alias.$col" : $col,
725 -colname => $colname,
728 $return{"$source_alias.$colname"} = $return{$col} if $col eq $colname;
734 # The DBIC relationship chaining implementation is pretty simple - every
735 # new related_relationship is pushed onto the {from} stack, and the {select}
736 # window simply slides further in. This means that when we count somewhere
737 # in the middle, we got to make sure that everything in the join chain is an
738 # actual inner join, otherwise the count will come back with unpredictable
739 # results (a resultset may be generated with _some_ rows regardless of if
740 # the relation which the $rs currently selects has rows or not). E.g.
741 # $artist_rs->cds->count - normally generates:
742 # SELECT COUNT( * ) FROM artist me LEFT JOIN cd cds ON cds.artist = me.artistid
743 # which actually returns the number of artists * (number of cds || 1)
745 # So what we do here is crawl {from}, determine if the current alias is at
746 # the top of the stack, and if not - make sure the chain is inner-joined down
749 sub _inner_join_to_node {
750 my ($self, $from, $alias) = @_;
752 # subqueries and other oddness are naturally not supported
758 ref $from->[0] ne 'HASH'
762 $from->[0]{-alias} eq $alias # this last bit means $alias is the head of $from - nothing to do
765 # find the current $alias in the $from structure
768 for my $j (@{$from}[1 .. $#$from]) {
769 if ($j->[0]{-alias} eq $alias) {
770 $switch_branch = $j->[0]{-join_path};
775 # something else went quite wrong
776 return $from unless $switch_branch;
778 # So it looks like we will have to switch some stuff around.
779 # local() is useless here as we will be leaving the scope
780 # anyway, and deep cloning is just too fucking expensive
781 # So replace the first hashref in the node arrayref manually
782 my @new_from = ($from->[0]);
783 my $sw_idx = { map { (values %$_), 1 } @$switch_branch }; #there's one k/v per join-path
785 for my $j (@{$from}[1 .. $#$from]) {
786 my $jalias = $j->[0]{-alias};
788 if ($sw_idx->{$jalias}) {
789 my %attrs = %{$j->[0]};
790 delete $attrs{-join_type};
804 sub _extract_order_criteria {
805 my ($self, $order_by, $sql_maker) = @_;
808 my ($sql_maker, $order_by, $orig_quote_chars) = @_;
810 return scalar $sql_maker->_order_by_chunks ($order_by)
813 my ($lq, $rq, $sep) = map { quotemeta($_) } (
814 ($orig_quote_chars ? @$orig_quote_chars : $sql_maker->_quote_chars),
819 for ($sql_maker->_order_by_chunks ($order_by) ) {
820 my $chunk = ref $_ ? [ @$_ ] : [ $_ ];
821 ($chunk->[0]) = $sql_maker->_split_order_chunk($chunk->[0]);
823 # order criteria may have come back pre-quoted (literals and whatnot)
824 # this is fragile, but the best we can currently do
825 $chunk->[0] =~ s/^ $lq (.+?) $rq $sep $lq (.+?) $rq $/"$1.$2"/xe
826 or $chunk->[0] =~ s/^ $lq (.+) $rq $/$1/x;
828 push @chunks, $chunk;
835 return $parser->($sql_maker, $order_by);
838 $sql_maker = $self->sql_maker;
840 # pass these in to deal with literals coming from
841 # the user or the deep guts of prefetch
842 my $orig_quote_chars = [$sql_maker->_quote_chars];
844 local $sql_maker->{quote_char};
845 return $parser->($sql_maker, $order_by, $orig_quote_chars);
849 sub _order_by_is_stable {
850 my ($self, $ident, $order_by, $where) = @_;
853 (map { $_->[0] } $self->_extract_order_criteria($order_by)),
854 $where ? @{$self->_extract_fixed_condition_columns($where)} :(),
857 my $colinfo = $self->_resolve_column_info($ident, \@cols);
859 return keys %$colinfo
860 ? $self->_columns_comprise_identifying_set( $colinfo, \@cols )
865 sub _columns_comprise_identifying_set {
866 my ($self, $colinfo, $columns) = @_;
869 $cols_per_src -> {$_->{-source_alias}} -> {$_->{-colname}} = $_
870 for grep { defined $_ } @{$colinfo}{@$columns};
872 for (values %$cols_per_src) {
873 my $src = (values %$_)[0]->{-result_source};
874 return 1 if $src->_identifying_column_set($_);
880 # this is almost identical to the above, except it accepts only
881 # a single rsrc, and will succeed only if the first portion of the order
883 # returns that portion as a colinfo hashref on success
884 sub _main_source_order_by_portion_is_stable {
885 my ($self, $main_rsrc, $order_by, $where) = @_;
887 die "Huh... I expect a blessed result_source..."
888 if ref($main_rsrc) eq 'ARRAY';
892 ( $self->_extract_order_criteria($order_by) )
894 return unless @ord_cols;
896 my $colinfos = $self->_resolve_column_info($main_rsrc);
898 for (0 .. $#ord_cols) {
900 ! $colinfos->{$ord_cols[$_]}
902 $colinfos->{$ord_cols[$_]}{-result_source} != $main_rsrc
909 # we just truncated it above
910 return unless @ord_cols;
912 my $order_portion_ci = { map {
913 $colinfos->{$_}{-colname} => $colinfos->{$_},
914 $colinfos->{$_}{-fq_colname} => $colinfos->{$_},
917 # since all we check here are the start of the order_by belonging to the
918 # top level $rsrc, a present identifying set will mean that the resultset
919 # is ordered by its leftmost table in a stable manner
921 # RV of _identifying_column_set contains unqualified names only
922 my $unqualified_idset = $main_rsrc->_identifying_column_set({
924 $self->_resolve_column_info(
925 $main_rsrc, $self->_extract_fixed_condition_columns($where)
932 my %unqualified_idcols_from_order = map {
933 $order_portion_ci->{$_} ? ( $_ => $order_portion_ci->{$_} ) : ()
934 } @$unqualified_idset;
936 # extra optimization - cut the order_by at the end of the identifying set
937 # (just in case the user was stupid and overlooked the obvious)
938 for my $i (0 .. $#ord_cols) {
939 my $col = $ord_cols[$i];
940 my $unqualified_colname = $order_portion_ci->{$col}{-colname};
941 $ret_info->{$col} = { %{$order_portion_ci->{$col}}, -idx_in_order_subset => $i };
942 delete $unqualified_idcols_from_order{$ret_info->{$col}{-colname}};
944 # we didn't reach the end of the identifying portion yet
945 return $ret_info unless keys %unqualified_idcols_from_order;
948 die 'How did we get here...';
951 # returns an arrayref of column names which *definitely* have some
952 # sort of non-nullable equality requested in the given condition
953 # specification. This is used to figure out if a resultset is
954 # constrained to a column which is part of a unique constraint,
955 # which in turn allows us to better predict how ordering will behave
958 # this is a rudimentary, incomplete, and error-prone extractor
959 # however this is OK - it is conservative, and if we can not find
960 # something that is in fact there - the stack will recover gracefully
961 # Also - DQ and the mst it rode in on will save us all RSN!!!
962 sub _extract_fixed_condition_columns {
963 my ($self, $where) = @_;
965 return unless ref $where eq 'HASH';
968 for my $lhs (keys %$where) {
969 if ($lhs =~ /^\-and$/i) {
970 push @cols, ref $where->{$lhs} eq 'ARRAY'
971 ? ( map { @{ $self->_extract_fixed_condition_columns($_) } } @{$where->{$lhs}} )
972 : @{ $self->_extract_fixed_condition_columns($where->{$lhs}) }
975 elsif ($lhs !~ /^\-/) {
976 my $val = $where->{$lhs};
978 push @cols, $lhs if (defined $val and (
981 (ref $val eq 'HASH' and keys %$val == 1 and defined $val->{'='})