Commit | Line | Data |
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1 | package DBIx::Class::ResultSetColumn; |
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2 | |
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3 | use strict; |
4 | use warnings; |
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5 | |
2bb7b40b |
6 | use base 'DBIx::Class'; |
70c28808 |
7 | use DBIx::Class::Carp; |
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8 | use DBIx::Class::_Util 'fail_on_internal_wantarray'; |
64c50e81 |
9 | use namespace::clean; |
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10 | |
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11 | =head1 NAME |
12 | |
13 | DBIx::Class::ResultSetColumn - helpful methods for messing |
14 | with a single column of the resultset |
15 | |
16 | =head1 SYNOPSIS |
17 | |
18 | $rs = $schema->resultset('CD')->search({ artist => 'Tool' }); |
19 | $rs_column = $rs->get_column('year'); |
20 | $max_year = $rs_column->max; #returns latest year |
21 | |
22 | =head1 DESCRIPTION |
23 | |
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24 | A convenience class used to perform operations on a specific column of |
25 | a resultset. |
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26 | |
27 | =cut |
28 | |
29 | =head1 METHODS |
30 | |
31 | =head2 new |
32 | |
33 | my $obj = DBIx::Class::ResultSetColumn->new($rs, $column); |
34 | |
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35 | Creates a new resultset column object from the resultset and column |
36 | passed as params. Used internally by L<DBIx::Class::ResultSet/get_column>. |
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37 | |
38 | =cut |
39 | |
40 | sub new { |
41 | my ($class, $rs, $column) = @_; |
42 | $class = ref $class if ref $class; |
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43 | |
66e33361 |
44 | $rs->throw_exception('column must be supplied') unless $column; |
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45 | |
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46 | my $orig_attrs = $rs->_resolved_attrs; |
9b8930f4 |
47 | my $alias = $rs->current_source_alias; |
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48 | my $rsrc = $rs->result_source; |
472d7df3 |
49 | |
50 | # If $column can be found in the 'as' list of the parent resultset, use the |
51 | # corresponding element of its 'select' list (to keep any custom column |
52 | # definition set up with 'select' or '+select' attrs), otherwise use $column |
53 | # (to create a new column definition on-the-fly). |
54 | my $as_list = $orig_attrs->{as} || []; |
55 | my $select_list = $orig_attrs->{select} || []; |
87b12551 |
56 | my ($as_index) = grep { ($as_list->[$_] || "") eq $column } 0..$#$as_list; |
472d7df3 |
57 | my $select = defined $as_index ? $select_list->[$as_index] : $column; |
58 | |
aca094b4 |
59 | my $colmap; |
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60 | for ($rsrc->columns, $column) { |
61 | if ($_ =~ /^ \Q$alias\E \. ([^\.]+) $ /x) { |
62 | $colmap->{$_} = $1; |
63 | } |
64 | elsif ($_ !~ /\./) { |
65 | $colmap->{"$alias.$_"} = $_; |
66 | $colmap->{$_} = $_; |
67 | } |
68 | } |
69 | |
aca094b4 |
70 | my $new_parent_rs; |
472d7df3 |
71 | # analyze the order_by, and see if it is done over a function/nonexistentcolumn |
72 | # if this is the case we will need to wrap a subquery since the result of RSC |
73 | # *must* be a single column select |
472d7df3 |
74 | if ( |
75 | scalar grep |
2b3fc408 |
76 | { ! exists $colmap->{$_->[0]} } |
77 | ( $rsrc->schema->storage->_extract_order_criteria ($orig_attrs->{order_by} ) ) |
472d7df3 |
78 | ) { |
5716e003 |
79 | # nuke the prefetch before collapsing to sql |
aca094b4 |
80 | my $subq_rs = $rs->search_rs; |
37aafa2e |
81 | $subq_rs->{attrs}{join} = $subq_rs->_merge_joinpref_attr( $subq_rs->{attrs}{join}, delete $subq_rs->{attrs}{prefetch} ); |
9b8930f4 |
82 | $new_parent_rs = $subq_rs->as_subselect_rs; |
472d7df3 |
83 | } |
84 | |
85 | $new_parent_rs ||= $rs->search_rs; |
66e33361 |
86 | my $new_attrs = $new_parent_rs->{attrs} ||= {}; |
87 | |
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88 | # prefetch causes additional columns to be fetched, but we can not just make a new |
89 | # rs via the _resolved_attrs trick - we need to retain the separation between |
bed3a173 |
90 | # +select/+as and select/as. At the same time we want to preserve any joins that the |
91 | # prefetch would otherwise generate. |
37aafa2e |
92 | $new_attrs->{join} = $rs->_merge_joinpref_attr( $new_attrs->{join}, delete $new_attrs->{prefetch} ); |
b6e85b48 |
93 | |
d8dbe471 |
94 | # {collapse} would mean a has_many join was injected, which in turn means |
722c0140 |
95 | # we need to group *IF WE CAN* (only if the column in question is unique) |
f1693c0d |
96 | if (!$orig_attrs->{group_by} && $orig_attrs->{collapse}) { |
d8dbe471 |
97 | |
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98 | if ($colmap->{$select} and $rsrc->_identifying_column_set([$colmap->{$select}])) { |
99 | $new_attrs->{group_by} = [ $select ]; |
1e4f9fb3 |
100 | delete @{$new_attrs}{qw(distinct _grouped_by_distinct)}; # it is ignored when group_by is present |
d8dbe471 |
101 | } |
2b3fc408 |
102 | else { |
722c0140 |
103 | carp ( |
104 | "Attempting to retrieve non-unique column '$column' on a resultset containing " |
105 | . 'one-to-many joins will return duplicate results.' |
106 | ); |
107 | } |
d8dbe471 |
108 | } |
109 | |
722274d0 |
110 | return bless { |
111 | _select => $select, |
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112 | _as => $column, |
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113 | _parent_resultset => $new_parent_rs |
114 | }, $class; |
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115 | } |
116 | |
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117 | =head2 as_query |
658fa250 |
118 | |
119 | =over 4 |
120 | |
428a645e |
121 | =item Arguments: none |
658fa250 |
122 | |
00c12490 |
123 | =item Return Value: \[ $sql, L<@bind_values|DBIx::Class::ResultSet/DBIC BIND VALUES> ] |
658fa250 |
124 | |
125 | =back |
126 | |
127 | Returns the SQL query and bind vars associated with the invocant. |
128 | |
03834f77 |
129 | This is generally used as the RHS for a subquery. |
c7a9d102 |
130 | |
131 | =cut |
132 | |
0f6fc705 |
133 | sub as_query { return shift->_resultset->as_query(@_) } |
c7a9d102 |
134 | |
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135 | =head2 next |
136 | |
137 | =over 4 |
138 | |
139 | =item Arguments: none |
140 | |
141 | =item Return Value: $value |
142 | |
143 | =back |
144 | |
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145 | Returns the next value of the column in the resultset (or C<undef> if |
146 | there is none). |
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147 | |
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148 | Much like L<DBIx::Class::ResultSet/next> but just returning the |
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149 | one value. |
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150 | |
151 | =cut |
152 | |
153 | sub next { |
154 | my $self = shift; |
b7c79955 |
155 | |
156 | # using cursor so we don't inflate anything |
66521001 |
157 | my ($row) = $self->_resultset->cursor->next; |
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158 | |
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159 | return $row; |
160 | } |
161 | |
162 | =head2 all |
163 | |
164 | =over 4 |
165 | |
166 | =item Arguments: none |
167 | |
168 | =item Return Value: @values |
169 | |
170 | =back |
171 | |
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172 | Returns all values of the column in the resultset (or C<undef> if |
173 | there are none). |
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174 | |
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175 | Much like L<DBIx::Class::ResultSet/all> but returns values rather |
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176 | than result objects. |
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177 | |
178 | =cut |
179 | |
180 | sub all { |
181 | my $self = shift; |
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182 | |
183 | # using cursor so we don't inflate anything |
66521001 |
184 | return map { $_->[0] } $self->_resultset->cursor->all; |
185 | } |
186 | |
187 | =head2 reset |
188 | |
189 | =over 4 |
190 | |
191 | =item Arguments: none |
192 | |
193 | =item Return Value: $self |
194 | |
195 | =back |
196 | |
197 | Resets the underlying resultset's cursor, so you can iterate through the |
198 | elements of the column again. |
199 | |
200 | Much like L<DBIx::Class::ResultSet/reset>. |
201 | |
202 | =cut |
203 | |
204 | sub reset { |
205 | my $self = shift; |
206 | $self->_resultset->cursor->reset; |
b7c79955 |
207 | return $self; |
66521001 |
208 | } |
209 | |
210 | =head2 first |
211 | |
212 | =over 4 |
213 | |
214 | =item Arguments: none |
215 | |
216 | =item Return Value: $value |
217 | |
218 | =back |
219 | |
220 | Resets the underlying resultset and returns the next value of the column in the |
221 | resultset (or C<undef> if there is none). |
222 | |
223 | Much like L<DBIx::Class::ResultSet/first> but just returning the one value. |
224 | |
225 | =cut |
226 | |
227 | sub first { |
228 | my $self = shift; |
b7c79955 |
229 | |
230 | # using cursor so we don't inflate anything |
231 | $self->_resultset->cursor->reset; |
01dc6781 |
232 | my ($row) = $self->_resultset->cursor->next; |
b7c79955 |
233 | |
66521001 |
234 | return $row; |
2bb7b40b |
235 | } |
236 | |
4e55c3ae |
237 | =head2 single |
238 | |
239 | =over 4 |
240 | |
241 | =item Arguments: none |
242 | |
243 | =item Return Value: $value |
244 | |
245 | =back |
246 | |
247 | Much like L<DBIx::Class::ResultSet/single> fetches one and only one column |
248 | value using the cursor directly. If additional rows are present a warning |
249 | is issued before discarding the cursor. |
250 | |
251 | =cut |
252 | |
253 | sub single { |
254 | my $self = shift; |
255 | |
256 | my $attrs = $self->_resultset->_resolved_attrs; |
257 | my ($row) = $self->_resultset->result_source->storage->select_single( |
258 | $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs |
259 | ); |
260 | |
261 | return $row; |
262 | } |
263 | |
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264 | =head2 min |
265 | |
266 | =over 4 |
267 | |
268 | =item Arguments: none |
269 | |
270 | =item Return Value: $lowest_value |
271 | |
272 | =back |
273 | |
eb98561c |
274 | my $first_year = $year_col->min(); |
275 | |
276 | Wrapper for ->func. Returns the lowest value of the column in the |
277 | resultset (or C<undef> if there are none). |
2bb7b40b |
278 | |
279 | =cut |
280 | |
281 | sub min { |
6b051e14 |
282 | return shift->func('MIN'); |
2bb7b40b |
283 | } |
284 | |
4fa7bc22 |
285 | =head2 min_rs |
286 | |
287 | =over 4 |
288 | |
289 | =item Arguments: none |
290 | |
fb13a49f |
291 | =item Return Value: L<$resultset|DBIx::Class::ResultSet> |
4fa7bc22 |
292 | |
293 | =back |
294 | |
295 | my $rs = $year_col->min_rs(); |
296 | |
297 | Wrapper for ->func_rs for function MIN(). |
298 | |
299 | =cut |
300 | |
301 | sub min_rs { return shift->func_rs('MIN') } |
302 | |
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303 | =head2 max |
304 | |
305 | =over 4 |
306 | |
307 | =item Arguments: none |
308 | |
309 | =item Return Value: $highest_value |
310 | |
311 | =back |
312 | |
eb98561c |
313 | my $last_year = $year_col->max(); |
314 | |
315 | Wrapper for ->func. Returns the highest value of the column in the |
316 | resultset (or C<undef> if there are none). |
2bb7b40b |
317 | |
318 | =cut |
319 | |
320 | sub max { |
6b051e14 |
321 | return shift->func('MAX'); |
2bb7b40b |
322 | } |
323 | |
4fa7bc22 |
324 | =head2 max_rs |
325 | |
326 | =over 4 |
327 | |
328 | =item Arguments: none |
329 | |
fb13a49f |
330 | =item Return Value: L<$resultset|DBIx::Class::ResultSet> |
4fa7bc22 |
331 | |
332 | =back |
333 | |
334 | my $rs = $year_col->max_rs(); |
335 | |
336 | Wrapper for ->func_rs for function MAX(). |
337 | |
338 | =cut |
339 | |
340 | sub max_rs { return shift->func_rs('MAX') } |
341 | |
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342 | =head2 sum |
343 | |
344 | =over 4 |
345 | |
346 | =item Arguments: none |
347 | |
348 | =item Return Value: $sum_of_values |
349 | |
350 | =back |
351 | |
eb98561c |
352 | my $total = $prices_col->sum(); |
353 | |
354 | Wrapper for ->func. Returns the sum of all the values in the column of |
355 | the resultset. Use on varchar-like columns at your own risk. |
2bb7b40b |
356 | |
357 | =cut |
358 | |
359 | sub sum { |
6b051e14 |
360 | return shift->func('SUM'); |
2bb7b40b |
361 | } |
362 | |
4fa7bc22 |
363 | =head2 sum_rs |
364 | |
365 | =over 4 |
366 | |
367 | =item Arguments: none |
368 | |
fb13a49f |
369 | =item Return Value: L<$resultset|DBIx::Class::ResultSet> |
4fa7bc22 |
370 | |
371 | =back |
372 | |
373 | my $rs = $year_col->sum_rs(); |
374 | |
375 | Wrapper for ->func_rs for function SUM(). |
376 | |
377 | =cut |
378 | |
379 | sub sum_rs { return shift->func_rs('SUM') } |
380 | |
2bb7b40b |
381 | =head2 func |
382 | |
383 | =over 4 |
384 | |
385 | =item Arguments: $function |
386 | |
387 | =item Return Value: $function_return_value |
388 | |
389 | =back |
390 | |
e8419341 |
391 | $rs = $schema->resultset("CD")->search({}); |
392 | $length = $rs->get_column('title')->func('LENGTH'); |
2bb7b40b |
393 | |
eb98561c |
394 | Runs a query using the function on the column and returns the |
395 | value. Produces the following SQL: |
396 | |
397 | SELECT LENGTH( title ) FROM cd me |
2bb7b40b |
398 | |
399 | =cut |
400 | |
401 | sub func { |
6b051e14 |
402 | my ($self,$function) = @_; |
4fa7bc22 |
403 | my $cursor = $self->func_rs($function)->cursor; |
d4daee7b |
404 | |
5d62876f |
405 | if( wantarray ) { |
e89c7968 |
406 | DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_WANTARRAY and my $sog = fail_on_internal_wantarray; |
5d62876f |
407 | return map { $_->[ 0 ] } $cursor->all; |
408 | } |
409 | |
410 | return ( $cursor->next )[ 0 ]; |
2bb7b40b |
411 | } |
412 | |
4fa7bc22 |
413 | =head2 func_rs |
414 | |
415 | =over 4 |
416 | |
417 | =item Arguments: $function |
418 | |
fb13a49f |
419 | =item Return Value: L<$resultset|DBIx::Class::ResultSet> |
4fa7bc22 |
420 | |
421 | =back |
422 | |
423 | Creates the resultset that C<func()> uses to run its query. |
424 | |
425 | =cut |
426 | |
427 | sub func_rs { |
428 | my ($self,$function) = @_; |
3214abc7 |
429 | |
430 | my $rs = $self->{_parent_resultset}; |
431 | my $select = $self->{_select}; |
432 | |
433 | # wrap a grouped rs |
434 | if ($rs->_resolved_attrs->{group_by}) { |
435 | $select = $self->{_as}; |
436 | $rs = $rs->as_subselect_rs; |
437 | } |
438 | |
439 | $rs->search( undef, { |
440 | columns => { $self->{_as} => { $function => $select } } |
441 | } ); |
4fa7bc22 |
442 | } |
443 | |
5d1fc7dc |
444 | =head2 throw_exception |
445 | |
446 | See L<DBIx::Class::Schema/throw_exception> for details. |
d4daee7b |
447 | |
8273e845 |
448 | =cut |
d4daee7b |
449 | |
5d1fc7dc |
450 | sub throw_exception { |
f9080e45 |
451 | my $self = shift; |
1a58752c |
452 | |
5d1fc7dc |
453 | if (ref $self && $self->{_parent_resultset}) { |
1a58752c |
454 | $self->{_parent_resultset}->throw_exception(@_); |
455 | } |
456 | else { |
457 | DBIx::Class::Exception->throw(@_); |
5d1fc7dc |
458 | } |
459 | } |
460 | |
b6e85b48 |
461 | # _resultset |
462 | # |
463 | # Arguments: none |
464 | # |
465 | # Return Value: $resultset |
466 | # |
467 | # $year_col->_resultset->next |
468 | # |
469 | # Returns the underlying resultset. Creates it from the parent resultset if |
470 | # necessary. |
b7c79955 |
471 | # |
66521001 |
472 | sub _resultset { |
473 | my $self = shift; |
474 | |
722274d0 |
475 | return $self->{_resultset} ||= do { |
476 | |
477 | my $select = $self->{_select}; |
478 | |
479 | if ($self->{_parent_resultset}{attrs}{distinct}) { |
480 | my $alias = $self->{_parent_resultset}->current_source_alias; |
481 | my $rsrc = $self->{_parent_resultset}->result_source; |
482 | my %cols = map { $_ => 1, "$alias.$_" => 1 } $rsrc->columns; |
483 | |
484 | unless( $cols{$select} ) { |
485 | carp_unique( |
486 | 'Use of distinct => 1 while selecting anything other than a column ' |
885c3dbd |
487 | . 'declared on the primary ResultSource is deprecated (you selected ' |
488 | . "'$self->{_as}') - please supply an explicit group_by instead" |
722274d0 |
489 | ); |
490 | |
491 | # collapse the selector to a literal so that it survives the distinct parse |
492 | # if it turns out to be an aggregate - at least the user will get a proper exception |
493 | # instead of silent drop of the group_by altogether |
ad1d374e |
494 | $select = \[ $rsrc->storage->sql_maker->_recurse_fields($select) ]; |
722274d0 |
495 | } |
66521001 |
496 | } |
722274d0 |
497 | |
498 | $self->{_parent_resultset}->search(undef, { |
499 | columns => { $self->{_as} => $select } |
500 | }); |
501 | }; |
66521001 |
502 | } |
503 | |
a2bd3796 |
504 | =head1 FURTHER QUESTIONS? |
2bb7b40b |
505 | |
a2bd3796 |
506 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
eb98561c |
507 | |
a2bd3796 |
508 | =head1 COPYRIGHT AND LICENSE |
2bb7b40b |
509 | |
a2bd3796 |
510 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
511 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
512 | redistribute it and/or modify it under the same terms as the |
513 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |
2bb7b40b |
514 | |
515 | =cut |
a2bd3796 |
516 | |
517 | 1; |
518 | |