Commit | Line | Data |
c443438f |
1 | package #hide from PAUSE |
2 | DBIx::Class::Storage::DBIHacks; |
d28bb90d |
3 | |
4 | # |
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 |
7eb76996 |
7 | # display. The arrival of SQLA2 should immediately oboslete 90% of this |
d28bb90d |
8 | # |
9 | |
10 | use strict; |
11 | use warnings; |
12 | |
13 | use base 'DBIx::Class::Storage'; |
14 | use mro 'c3'; |
15 | |
16 | use Carp::Clan qw/^DBIx::Class/; |
17 | |
18 | # |
19 | # This is the code producing joined subqueries like: |
20 | # SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ... |
21 | # |
22 | sub _adjust_select_args_for_complex_prefetch { |
23 | my ($self, $from, $select, $where, $attrs) = @_; |
24 | |
25 | $self->throw_exception ('Nothing to prefetch... how did we get here?!') |
26 | if not @{$attrs->{_prefetch_select}}; |
27 | |
28 | $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute') |
29 | if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY'); |
30 | |
31 | |
32 | # generate inner/outer attribute lists, remove stuff that doesn't apply |
33 | my $outer_attrs = { %$attrs }; |
34 | delete $outer_attrs->{$_} for qw/where bind rows offset group_by having/; |
35 | |
36 | my $inner_attrs = { %$attrs }; |
37 | delete $inner_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/; |
38 | |
39 | |
40 | # bring over all non-collapse-induced order_by into the inner query (if any) |
41 | # the outer one will have to keep them all |
42 | delete $inner_attrs->{order_by}; |
43 | if (my $ord_cnt = @{$outer_attrs->{order_by}} - @{$outer_attrs->{_collapse_order_by}} ) { |
44 | $inner_attrs->{order_by} = [ |
45 | @{$outer_attrs->{order_by}}[ 0 .. $ord_cnt - 1] |
46 | ]; |
47 | } |
48 | |
49 | |
50 | # generate the inner/outer select lists |
51 | # for inside we consider only stuff *not* brought in by the prefetch |
52 | # on the outside we substitute any function for its alias |
53 | my $outer_select = [ @$select ]; |
54 | my $inner_select = []; |
55 | for my $i (0 .. ( @$outer_select - @{$outer_attrs->{_prefetch_select}} - 1) ) { |
56 | my $sel = $outer_select->[$i]; |
57 | |
58 | if (ref $sel eq 'HASH' ) { |
59 | $sel->{-as} ||= $attrs->{as}[$i]; |
60 | $outer_select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "inner_column_$i") ); |
61 | } |
62 | |
63 | push @$inner_select, $sel; |
64 | } |
65 | |
66 | # normalize a copy of $from, so it will be easier to work with further |
67 | # down (i.e. promote the initial hashref to an AoH) |
68 | $from = [ @$from ]; |
69 | $from->[0] = [ $from->[0] ]; |
d28bb90d |
70 | |
546f1cd9 |
71 | my ( $ra1, $sa1, $pa1 ) = |
72 | $self->_resolve_aliases_from_select_args( $from, $where, $inner_select, |
73 | $inner_attrs, ); |
74 | my ( $ra2, $sa2, $pa2 ) = |
75 | $self->_resolve_aliases_from_select_args( $from, $where, $outer_select, |
07f31d19 |
76 | $outer_attrs, ); |
546f1cd9 |
77 | my $restrict_aliases = { %$ra1, %$ra2 }; |
78 | my $select_aliases = { %$sa1, %$sa2 }; |
79 | my $prefetch_aliases = { %$pa1, %$pa2 }; |
d28bb90d |
80 | |
d28bb90d |
81 | # construct the inner $from for the subquery |
82 | my %inner_joins = (map { %{$_ || {}} } ($restrict_aliases, $select_aliases) ); |
83 | my @inner_from; |
84 | for my $j (@$from) { |
85 | push @inner_from, $j if $inner_joins{$j->[0]{-alias}}; |
86 | } |
87 | |
88 | # if a multi-type join was needed in the subquery ("multi" is indicated by |
89 | # presence in {collapse}) - add a group_by to simulate the collapse in the subq |
90 | unless ($inner_attrs->{group_by}) { |
91 | for my $alias (keys %inner_joins) { |
92 | |
93 | # the dot comes from some weirdness in collapse |
94 | # remove after the rewrite |
95 | if ($attrs->{collapse}{".$alias"}) { |
96 | $inner_attrs->{group_by} ||= $inner_select; |
97 | last; |
98 | } |
99 | } |
100 | } |
101 | |
102 | # demote the inner_from head |
103 | $inner_from[0] = $inner_from[0][0]; |
104 | |
105 | # generate the subquery |
106 | my $subq = $self->_select_args_to_query ( |
107 | \@inner_from, |
108 | $inner_select, |
109 | $where, |
110 | $inner_attrs, |
111 | ); |
112 | |
113 | my $subq_joinspec = { |
114 | -alias => $attrs->{alias}, |
115 | -source_handle => $inner_from[0]{-source_handle}, |
116 | $attrs->{alias} => $subq, |
117 | }; |
118 | |
119 | # Generate the outer from - this is relatively easy (really just replace |
120 | # the join slot with the subquery), with a major caveat - we can not |
121 | # join anything that is non-selecting (not part of the prefetch), but at |
122 | # the same time is a multi-type relationship, as it will explode the result. |
123 | # |
124 | # There are two possibilities here |
125 | # - either the join is non-restricting, in which case we simply throw it away |
126 | # - it is part of the restrictions, in which case we need to collapse the outer |
127 | # result by tackling yet another group_by to the outside of the query |
128 | |
129 | # so first generate the outer_from, up to the substitution point |
130 | my @outer_from; |
131 | while (my $j = shift @$from) { |
132 | if ($j->[0]{-alias} eq $attrs->{alias}) { # time to swap |
133 | push @outer_from, [ |
134 | $subq_joinspec, |
135 | @{$j}[1 .. $#$j], |
136 | ]; |
137 | last; # we'll take care of what's left in $from below |
138 | } |
139 | else { |
140 | push @outer_from, $j; |
141 | } |
142 | } |
143 | |
144 | # see what's left - throw away if not selecting/restricting |
145 | # also throw in a group_by if restricting to guard against |
146 | # cross-join explosions |
147 | # |
148 | while (my $j = shift @$from) { |
149 | my $alias = $j->[0]{-alias}; |
150 | |
151 | if ($select_aliases->{$alias} || $prefetch_aliases->{$alias}) { |
152 | push @outer_from, $j; |
153 | } |
154 | elsif ($restrict_aliases->{$alias}) { |
155 | push @outer_from, $j; |
156 | |
157 | # FIXME - this should be obviated by SQLA2, as I'll be able to |
158 | # have restrict_inner and restrict_outer... or something to that |
159 | # effect... I think... |
160 | |
161 | # FIXME2 - I can't find a clean way to determine if a particular join |
162 | # is a multi - instead I am just treating everything as a potential |
163 | # explosive join (ribasushi) |
164 | # |
165 | # if (my $handle = $j->[0]{-source_handle}) { |
166 | # my $rsrc = $handle->resolve; |
167 | # ... need to bail out of the following if this is not a multi, |
168 | # as it will be much easier on the db ... |
169 | |
170 | $outer_attrs->{group_by} ||= $outer_select; |
171 | # } |
172 | } |
173 | } |
174 | |
175 | # demote the outer_from head |
176 | $outer_from[0] = $outer_from[0][0]; |
177 | |
178 | # This is totally horrific - the $where ends up in both the inner and outer query |
179 | # Unfortunately not much can be done until SQLA2 introspection arrives, and even |
180 | # then if where conditions apply to the *right* side of the prefetch, you may have |
181 | # to both filter the inner select (e.g. to apply a limit) and then have to re-filter |
182 | # the outer select to exclude joins you didin't want in the first place |
183 | # |
184 | # OTOH it can be seen as a plus: <ash> (notes that this query would make a DBA cry ;) |
185 | return (\@outer_from, $outer_select, $where, $outer_attrs); |
186 | } |
187 | |
546f1cd9 |
188 | sub _resolve_aliases_from_select_args { |
189 | my ( $self, $from, $where, $select, $attrs ) = @_; |
190 | |
191 | my %original_join_info = map { $_->[0]{-alias} => $_->[0] } (@$from); |
192 | # decide which parts of the join will remain in either part of |
193 | # the outer/inner query |
194 | |
195 | # First we compose a list of which aliases are used in restrictions |
196 | # (i.e. conditions/order/grouping/etc). Since we do not have |
197 | # introspectable SQLA, we fall back to ugly scanning of raw SQL for |
198 | # WHERE, and for pieces of ORDER BY in order to determine which aliases |
199 | # need to appear in the resulting sql. |
200 | # It may not be very efficient, but it's a reasonable stop-gap |
201 | # Also unqualified column names will not be considered, but more often |
202 | # than not this is actually ok |
203 | # |
204 | # In the same loop we enumerate part of the selection aliases, as |
205 | # it requires the same sqla hack for the time being |
206 | my ( $restrict_aliases, $select_aliases, $prefetch_aliases ) = ( {}, {}, {} ); |
207 | { |
208 | # produce stuff unquoted, so it can be scanned |
209 | my $sql_maker = $self->sql_maker; |
210 | local $sql_maker->{quote_char}; |
211 | my $sep = $self->_sql_maker_opts->{name_sep} || '.'; |
212 | $sep = "\Q$sep\E"; |
213 | |
214 | my $non_prefetch_select_sql = $sql_maker->_recurse_fields ($select) || ''; |
215 | my $prefetch_select_sql = $sql_maker->_recurse_fields ($attrs->{_prefetch_select}) || ''; |
216 | my $where_sql = $sql_maker->where ($where); |
217 | my $group_by_sql = $sql_maker->_order_by({ |
218 | map { $_ => $attrs->{$_} } qw/group_by having/ |
219 | }) || ''; |
220 | my @non_prefetch_order_by_chunks = (map |
221 | { ref $_ ? $_->[0] : $_ } |
222 | $sql_maker->_order_by_chunks ($attrs->{order_by}) |
223 | ); |
224 | |
225 | |
226 | for my $alias (keys %original_join_info) { |
227 | my $seen_re = qr/\b $alias $sep/x; |
228 | |
229 | for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) { |
230 | if ($piece =~ $seen_re) { |
231 | $restrict_aliases->{$alias} = 1; |
232 | } |
233 | } |
234 | |
235 | if ($non_prefetch_select_sql =~ $seen_re) { |
236 | $select_aliases->{$alias} = 1; |
237 | } |
238 | |
239 | if ($prefetch_select_sql =~ $seen_re) { |
240 | $prefetch_aliases->{$alias} = 1; |
241 | } |
242 | |
243 | } |
244 | } |
245 | |
246 | # Add any non-left joins to the restriction list (such joins are indeed restrictions) |
247 | for my $j (values %original_join_info) { |
248 | my $alias = $j->{-alias} or next; |
249 | $restrict_aliases->{$alias} = 1 if ( |
250 | (not $j->{-join_type}) |
251 | or |
252 | ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi) |
253 | ); |
254 | } |
255 | |
256 | # mark all join parents as mentioned |
257 | # (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too ) |
258 | for my $collection ($restrict_aliases, $select_aliases) { |
259 | for my $alias (keys %$collection) { |
260 | $collection->{$_} = 1 |
261 | for (@{ $original_join_info{$alias}{-join_path} || [] }); |
262 | } |
263 | } |
264 | return ( $restrict_aliases, $select_aliases, $prefetch_aliases ); |
265 | } |
266 | |
07f31d19 |
267 | sub _choose_aliases_to_include { |
268 | my ( $self, $from, $where, $inner_select, $inner_attrs, $outer_select, |
269 | $outer_attrs ) = @_; |
270 | |
271 | my %original_join_info = map { $_->[0]{-alias} => $_->[0] } (@$from); |
272 | # decide which parts of the join will remain in either part of |
273 | # the outer/inner query |
274 | |
275 | # First we compose a list of which aliases are used in restrictions |
276 | # (i.e. conditions/order/grouping/etc). Since we do not have |
277 | # introspectable SQLA, we fall back to ugly scanning of raw SQL for |
278 | # WHERE, and for pieces of ORDER BY in order to determine which aliases |
279 | # need to appear in the resulting sql. |
280 | # It may not be very efficient, but it's a reasonable stop-gap |
281 | # Also unqualified column names will not be considered, but more often |
282 | # than not this is actually ok |
283 | # |
284 | # In the same loop we enumerate part of the selection aliases, as |
285 | # it requires the same sqla hack for the time being |
286 | my ($restrict_aliases, $select_aliases, $prefetch_aliases); |
287 | { |
288 | # produce stuff unquoted, so it can be scanned |
289 | my $sql_maker = $self->sql_maker; |
290 | local $sql_maker->{quote_char}; |
291 | my $sep = $self->_sql_maker_opts->{name_sep} || '.'; |
292 | $sep = "\Q$sep\E"; |
293 | |
294 | my $non_prefetch_select_sql = $sql_maker->_recurse_fields ($inner_select); |
295 | my $prefetch_select_sql = $sql_maker->_recurse_fields ($outer_attrs->{_prefetch_select}); |
296 | my $where_sql = $sql_maker->where ($where); |
297 | my $group_by_sql = $sql_maker->_order_by({ |
298 | map { $_ => $inner_attrs->{$_} } qw/group_by having/ |
299 | }); |
300 | my @non_prefetch_order_by_chunks = (map |
301 | { ref $_ ? $_->[0] : $_ } |
302 | $sql_maker->_order_by_chunks ($inner_attrs->{order_by}) |
303 | ); |
304 | |
305 | |
306 | for my $alias (keys %original_join_info) { |
307 | my $seen_re = qr/\b $alias $sep/x; |
308 | |
309 | for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) { |
310 | if ($piece =~ $seen_re) { |
311 | $restrict_aliases->{$alias} = 1; |
312 | } |
313 | } |
314 | |
315 | if ($non_prefetch_select_sql =~ $seen_re) { |
316 | $select_aliases->{$alias} = 1; |
317 | } |
318 | |
319 | if ($prefetch_select_sql =~ $seen_re) { |
320 | $prefetch_aliases->{$alias} = 1; |
321 | } |
322 | |
323 | } |
324 | } |
325 | |
326 | # Add any non-left joins to the restriction list (such joins are indeed restrictions) |
327 | for my $j (values %original_join_info) { |
328 | my $alias = $j->{-alias} or next; |
329 | $restrict_aliases->{$alias} = 1 if ( |
330 | (not $j->{-join_type}) |
331 | or |
332 | ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi) |
333 | ); |
334 | } |
335 | |
336 | # mark all join parents as mentioned |
337 | # (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too ) |
338 | for my $collection ($restrict_aliases, $select_aliases) { |
339 | for my $alias (keys %$collection) { |
340 | $collection->{$_} = 1 |
341 | for (@{ $original_join_info{$alias}{-join_path} || [] }); |
342 | } |
343 | } |
344 | return ( $restrict_aliases, $select_aliases, $prefetch_aliases ); |
345 | } |
346 | |
d28bb90d |
347 | sub _resolve_ident_sources { |
348 | my ($self, $ident) = @_; |
349 | |
350 | my $alias2source = {}; |
351 | my $rs_alias; |
352 | |
353 | # the reason this is so contrived is that $ident may be a {from} |
354 | # structure, specifying multiple tables to join |
355 | if ( Scalar::Util::blessed($ident) && $ident->isa("DBIx::Class::ResultSource") ) { |
356 | # this is compat mode for insert/update/delete which do not deal with aliases |
357 | $alias2source->{me} = $ident; |
358 | $rs_alias = 'me'; |
359 | } |
360 | elsif (ref $ident eq 'ARRAY') { |
361 | |
362 | for (@$ident) { |
363 | my $tabinfo; |
364 | if (ref $_ eq 'HASH') { |
365 | $tabinfo = $_; |
366 | $rs_alias = $tabinfo->{-alias}; |
367 | } |
368 | if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') { |
369 | $tabinfo = $_->[0]; |
370 | } |
371 | |
372 | $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-source_handle}->resolve |
373 | if ($tabinfo->{-source_handle}); |
374 | } |
375 | } |
376 | |
377 | return ($alias2source, $rs_alias); |
378 | } |
379 | |
380 | # Takes $ident, \@column_names |
381 | # |
382 | # returns { $column_name => \%column_info, ... } |
383 | # also note: this adds -result_source => $rsrc to the column info |
384 | # |
09e14fdc |
385 | # If no columns_names are supplied returns info about *all* columns |
386 | # for all sources |
d28bb90d |
387 | sub _resolve_column_info { |
388 | my ($self, $ident, $colnames) = @_; |
389 | my ($alias2src, $root_alias) = $self->_resolve_ident_sources($ident); |
390 | |
391 | my $sep = $self->_sql_maker_opts->{name_sep} || '.'; |
09e14fdc |
392 | my $qsep = quotemeta $sep; |
d28bb90d |
393 | |
09e14fdc |
394 | my (%return, %seen_cols, @auto_colnames); |
d28bb90d |
395 | |
396 | # compile a global list of column names, to be able to properly |
397 | # disambiguate unqualified column names (if at all possible) |
398 | for my $alias (keys %$alias2src) { |
399 | my $rsrc = $alias2src->{$alias}; |
400 | for my $colname ($rsrc->columns) { |
401 | push @{$seen_cols{$colname}}, $alias; |
09e14fdc |
402 | push @auto_colnames, "$alias$sep$colname" unless $colnames; |
d28bb90d |
403 | } |
404 | } |
405 | |
09e14fdc |
406 | $colnames ||= [ |
407 | @auto_colnames, |
408 | grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols), |
409 | ]; |
410 | |
d28bb90d |
411 | COLUMN: |
412 | foreach my $col (@$colnames) { |
09e14fdc |
413 | my ($alias, $colname) = $col =~ m/^ (?: ([^$qsep]+) $qsep)? (.+) $/x; |
d28bb90d |
414 | |
415 | unless ($alias) { |
416 | # see if the column was seen exactly once (so we know which rsrc it came from) |
417 | if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1) { |
418 | $alias = $seen_cols{$colname}[0]; |
419 | } |
420 | else { |
421 | next COLUMN; |
422 | } |
423 | } |
424 | |
425 | my $rsrc = $alias2src->{$alias}; |
426 | $return{$col} = $rsrc && { |
427 | %{$rsrc->column_info($colname)}, |
428 | -result_source => $rsrc, |
429 | -source_alias => $alias, |
430 | }; |
431 | } |
432 | |
433 | return \%return; |
434 | } |
435 | |
289ac713 |
436 | # The DBIC relationship chaining implementation is pretty simple - every |
437 | # new related_relationship is pushed onto the {from} stack, and the {select} |
438 | # window simply slides further in. This means that when we count somewhere |
439 | # in the middle, we got to make sure that everything in the join chain is an |
440 | # actual inner join, otherwise the count will come back with unpredictable |
441 | # results (a resultset may be generated with _some_ rows regardless of if |
442 | # the relation which the $rs currently selects has rows or not). E.g. |
443 | # $artist_rs->cds->count - normally generates: |
444 | # SELECT COUNT( * ) FROM artist me LEFT JOIN cd cds ON cds.artist = me.artistid |
445 | # which actually returns the number of artists * (number of cds || 1) |
446 | # |
447 | # So what we do here is crawl {from}, determine if the current alias is at |
448 | # the top of the stack, and if not - make sure the chain is inner-joined down |
449 | # to the root. |
450 | # |
451 | sub _straight_join_to_node { |
452 | my ($self, $from, $alias) = @_; |
453 | |
454 | # subqueries and other oddness are naturally not supported |
455 | return $from if ( |
456 | ref $from ne 'ARRAY' |
457 | || |
458 | @$from <= 1 |
459 | || |
460 | ref $from->[0] ne 'HASH' |
461 | || |
462 | ! $from->[0]{-alias} |
463 | || |
7eb76996 |
464 | $from->[0]{-alias} eq $alias # this last bit means $alias is the head of $from - nothing to do |
289ac713 |
465 | ); |
466 | |
467 | # find the current $alias in the $from structure |
468 | my $switch_branch; |
469 | JOINSCAN: |
470 | for my $j (@{$from}[1 .. $#$from]) { |
471 | if ($j->[0]{-alias} eq $alias) { |
472 | $switch_branch = $j->[0]{-join_path}; |
473 | last JOINSCAN; |
474 | } |
475 | } |
476 | |
7eb76996 |
477 | # something else went quite wrong |
289ac713 |
478 | return $from unless $switch_branch; |
479 | |
480 | # So it looks like we will have to switch some stuff around. |
481 | # local() is useless here as we will be leaving the scope |
482 | # anyway, and deep cloning is just too fucking expensive |
7eb76996 |
483 | # So replace the first hashref in the node arrayref manually |
289ac713 |
484 | my @new_from = ($from->[0]); |
485 | my $sw_idx = { map { $_ => 1 } @$switch_branch }; |
486 | |
487 | for my $j (@{$from}[1 .. $#$from]) { |
488 | my $jalias = $j->[0]{-alias}; |
489 | |
490 | if ($sw_idx->{$jalias}) { |
491 | my %attrs = %{$j->[0]}; |
492 | delete $attrs{-join_type}; |
493 | push @new_from, [ |
494 | \%attrs, |
495 | @{$j}[ 1 .. $#$j ], |
496 | ]; |
497 | } |
498 | else { |
499 | push @new_from, $j; |
500 | } |
501 | } |
502 | |
503 | return \@new_from; |
504 | } |
505 | |
bac6c4fb |
506 | # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus |
507 | # a condition containing 'me' or other table prefixes will not work |
508 | # at all. What this code tries to do (badly) is introspect the condition |
509 | # and remove all column qualifiers. If it bails out early (returns undef) |
510 | # the calling code should try another approach (e.g. a subquery) |
511 | sub _strip_cond_qualifiers { |
512 | my ($self, $where) = @_; |
513 | |
514 | my $cond = {}; |
515 | |
516 | # No-op. No condition, we're updating/deleting everything |
517 | return $cond unless $where; |
518 | |
519 | if (ref $where eq 'ARRAY') { |
520 | $cond = [ |
521 | map { |
522 | my %hash; |
523 | foreach my $key (keys %{$_}) { |
524 | $key =~ /([^.]+)$/; |
525 | $hash{$1} = $_->{$key}; |
526 | } |
527 | \%hash; |
528 | } @$where |
529 | ]; |
530 | } |
531 | elsif (ref $where eq 'HASH') { |
532 | if ( (keys %$where) == 1 && ( (keys %{$where})[0] eq '-and' )) { |
533 | $cond->{-and} = []; |
534 | my @cond = @{$where->{-and}}; |
535 | for (my $i = 0; $i < @cond; $i++) { |
536 | my $entry = $cond[$i]; |
537 | my $hash; |
538 | if (ref $entry eq 'HASH') { |
539 | $hash = $self->_strip_cond_qualifiers($entry); |
540 | } |
541 | else { |
542 | $entry =~ /([^.]+)$/; |
543 | $hash->{$1} = $cond[++$i]; |
544 | } |
545 | push @{$cond->{-and}}, $hash; |
546 | } |
547 | } |
548 | else { |
549 | foreach my $key (keys %$where) { |
550 | $key =~ /([^.]+)$/; |
551 | $cond->{$1} = $where->{$key}; |
552 | } |
553 | } |
554 | } |
555 | else { |
556 | return undef; |
557 | } |
558 | |
559 | return $cond; |
560 | } |
561 | |
562 | |
d28bb90d |
563 | 1; |