Commit | Line | Data |
89c0a5a2 |
1 | package DBIx::Class::ResultSet; |
2 | |
3 | use strict; |
4 | use warnings; |
5 | use overload |
ebaefbc2 |
6 | '0+' => \&count, |
a910dc57 |
7 | 'bool' => sub { 1; }, |
89c0a5a2 |
8 | fallback => 1; |
3c5b25c5 |
9 | use Data::Page; |
ea20d0fd |
10 | use Storable; |
89c0a5a2 |
11 | |
701da8c4 |
12 | use base qw/DBIx::Class/; |
13 | __PACKAGE__->load_components(qw/AccessorGroup/); |
a50bcd52 |
14 | __PACKAGE__->mk_group_accessors('simple' => qw/result_source result_class/); |
701da8c4 |
15 | |
ee38fa40 |
16 | =head1 NAME |
17 | |
bfab575a |
18 | DBIx::Class::ResultSet - Responsible for fetching and creating resultset. |
ee38fa40 |
19 | |
bfab575a |
20 | =head1 SYNOPSIS |
ee38fa40 |
21 | |
a33df5d4 |
22 | my $rs = $schema->resultset('User')->search(registered => 1); |
23 | my @rows = $schema->resultset('Foo')->search(bar => 'baz'); |
ee38fa40 |
24 | |
25 | =head1 DESCRIPTION |
26 | |
bfab575a |
27 | The resultset is also known as an iterator. It is responsible for handling |
a33df5d4 |
28 | queries that may return an arbitrary number of rows, e.g. via L</search> |
bfab575a |
29 | or a C<has_many> relationship. |
ee38fa40 |
30 | |
a33df5d4 |
31 | In the examples below, the following table classes are used: |
32 | |
33 | package MyApp::Schema::Artist; |
34 | use base qw/DBIx::Class/; |
f4409169 |
35 | __PACKAGE__->load_components(qw/Core/); |
a33df5d4 |
36 | __PACKAGE__->table('artist'); |
37 | __PACKAGE__->add_columns(qw/artistid name/); |
38 | __PACKAGE__->set_primary_key('artistid'); |
39 | __PACKAGE__->has_many(cds => 'MyApp::Schema::CD'); |
40 | 1; |
41 | |
42 | package MyApp::Schema::CD; |
43 | use base qw/DBIx::Class/; |
f4409169 |
44 | __PACKAGE__->load_components(qw/Core/); |
45 | __PACKAGE__->table('cd'); |
a33df5d4 |
46 | __PACKAGE__->add_columns(qw/cdid artist title year/); |
47 | __PACKAGE__->set_primary_key('cdid'); |
48 | __PACKAGE__->belongs_to(artist => 'MyApp::Schema::Artist'); |
49 | 1; |
50 | |
ee38fa40 |
51 | =head1 METHODS |
52 | |
87c4e602 |
53 | =head2 new |
54 | |
55 | =head3 Arguments: ($source, \%$attrs) |
ee38fa40 |
56 | |
a33df5d4 |
57 | The resultset constructor. Takes a source object (usually a |
181a28f4 |
58 | L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see L</ATTRIBUTES> |
a33df5d4 |
59 | below). Does not perform any queries -- these are executed as needed by the |
60 | other methods. |
61 | |
62 | Generally you won't need to construct a resultset manually. You'll |
63 | automatically get one from e.g. a L</search> called in scalar context: |
64 | |
65 | my $rs = $schema->resultset('CD')->search({ title => '100th Window' }); |
ee38fa40 |
66 | |
67 | =cut |
68 | |
89c0a5a2 |
69 | sub new { |
fea3d045 |
70 | my $class = shift; |
f9db5527 |
71 | return $class->new_result(@_) if ref $class; |
fea3d045 |
72 | my ($source, $attrs) = @_; |
b98e75f6 |
73 | #use Data::Dumper; warn Dumper($attrs); |
ea20d0fd |
74 | $attrs = Storable::dclone($attrs || {}); # { %{ $attrs || {} } }; |
c7ce65e6 |
75 | my %seen; |
6aeb9185 |
76 | my $alias = ($attrs->{alias} ||= 'me'); |
a9433341 |
77 | if ($attrs->{cols} || !$attrs->{select}) { |
78 | delete $attrs->{as} if $attrs->{cols}; |
976f3686 |
79 | my @cols = ($attrs->{cols} |
80 | ? @{delete $attrs->{cols}} |
a9433341 |
81 | : $source->columns); |
6aeb9185 |
82 | $attrs->{select} = [ map { m/\./ ? $_ : "${alias}.$_" } @cols ]; |
976f3686 |
83 | } |
6aeb9185 |
84 | $attrs->{as} ||= [ map { m/^$alias\.(.*)$/ ? $1 : $_ } @{$attrs->{select}} ]; |
5ac6a044 |
85 | if (my $include = delete $attrs->{include_columns}) { |
86 | push(@{$attrs->{select}}, @$include); |
87 | push(@{$attrs->{as}}, map { m/([^\.]+)$/; $1; } @$include); |
88 | } |
976f3686 |
89 | #use Data::Dumper; warn Dumper(@{$attrs}{qw/select as/}); |
fea3d045 |
90 | $attrs->{from} ||= [ { $alias => $source->from } ]; |
8fab5eef |
91 | $attrs->{seen_join} ||= {}; |
b52e9bf8 |
92 | if (my $join = delete $attrs->{join}) { |
93 | foreach my $j (ref $join eq 'ARRAY' |
94 | ? (@{$join}) : ($join)) { |
c7ce65e6 |
95 | if (ref $j eq 'HASH') { |
96 | $seen{$_} = 1 foreach keys %$j; |
97 | } else { |
98 | $seen{$j} = 1; |
99 | } |
100 | } |
8fab5eef |
101 | push(@{$attrs->{from}}, $source->resolve_join($join, $attrs->{alias}, $attrs->{seen_join})); |
c7ce65e6 |
102 | } |
54540863 |
103 | $attrs->{group_by} ||= $attrs->{select} if delete $attrs->{distinct}; |
b3e8ac9b |
104 | |
a86b1efe |
105 | $attrs->{order_by} = [ $attrs->{order_by} ] |
106 | if $attrs->{order_by} && !ref($attrs->{order_by}); |
107 | $attrs->{order_by} ||= []; |
108 | |
0f66a01b |
109 | my $collapse = {}; |
110 | |
b3e8ac9b |
111 | if (my $prefetch = delete $attrs->{prefetch}) { |
0f66a01b |
112 | my @pre_order; |
b3e8ac9b |
113 | foreach my $p (ref $prefetch eq 'ARRAY' |
114 | ? (@{$prefetch}) : ($prefetch)) { |
115 | if( ref $p eq 'HASH' ) { |
116 | foreach my $key (keys %$p) { |
117 | push(@{$attrs->{from}}, $source->resolve_join($p, $attrs->{alias})) |
118 | unless $seen{$key}; |
119 | } |
120 | } |
121 | else { |
122 | push(@{$attrs->{from}}, $source->resolve_join($p, $attrs->{alias})) |
123 | unless $seen{$p}; |
124 | } |
a86b1efe |
125 | my @prefetch = $source->resolve_prefetch( |
0f66a01b |
126 | $p, $attrs->{alias}, {}, \@pre_order, $collapse); |
b3e8ac9b |
127 | #die Dumper \@cols; |
489709af |
128 | push(@{$attrs->{select}}, map { $_->[0] } @prefetch); |
129 | push(@{$attrs->{as}}, map { $_->[1] } @prefetch); |
b3e8ac9b |
130 | } |
0f66a01b |
131 | push(@{$attrs->{order_by}}, @pre_order); |
fef5d100 |
132 | } |
b3e8ac9b |
133 | |
6aeb9185 |
134 | if ($attrs->{page}) { |
135 | $attrs->{rows} ||= 10; |
136 | $attrs->{offset} ||= 0; |
137 | $attrs->{offset} += ($attrs->{rows} * ($attrs->{page} - 1)); |
138 | } |
0f66a01b |
139 | |
140 | #if (keys %{$collapse}) { |
141 | # use Data::Dumper; warn Dumper($collapse); |
142 | #} |
143 | |
89c0a5a2 |
144 | my $new = { |
701da8c4 |
145 | result_source => $source, |
a50bcd52 |
146 | result_class => $attrs->{result_class} || $source->result_class, |
89c0a5a2 |
147 | cond => $attrs->{where}, |
0a3c5b43 |
148 | from => $attrs->{from}, |
0f66a01b |
149 | collapse => $collapse, |
3c5b25c5 |
150 | count => undef, |
93b004d3 |
151 | page => delete $attrs->{page}, |
3c5b25c5 |
152 | pager => undef, |
89c0a5a2 |
153 | attrs => $attrs }; |
2f5911b2 |
154 | bless ($new, $class); |
9229f20a |
155 | return $new; |
89c0a5a2 |
156 | } |
157 | |
bfab575a |
158 | =head2 search |
0a3c5b43 |
159 | |
87f0da6a |
160 | my @obj = $rs->search({ foo => 3 }); # "... WHERE foo = 3" |
161 | my $new_rs = $rs->search({ foo => 3 }); |
162 | |
6009260a |
163 | If you need to pass in additional attributes but no additional condition, |
a33df5d4 |
164 | call it as C<search({}, \%attrs);>. |
87f0da6a |
165 | |
a33df5d4 |
166 | # "SELECT foo, bar FROM $class_table" |
167 | my @all = $class->search({}, { cols => [qw/foo bar/] }); |
0a3c5b43 |
168 | |
169 | =cut |
170 | |
171 | sub search { |
172 | my $self = shift; |
173 | |
ff7bb7a1 |
174 | my $rs; |
175 | if( @_ ) { |
176 | |
177 | my $attrs = { %{$self->{attrs}} }; |
8839560b |
178 | my $having = delete $attrs->{having}; |
ff7bb7a1 |
179 | if (@_ > 1 && ref $_[$#_] eq 'HASH') { |
180 | $attrs = { %$attrs, %{ pop(@_) } }; |
181 | } |
6009260a |
182 | |
3e0e9e27 |
183 | my $where = (@_ |
184 | ? ((@_ == 1 || ref $_[0] eq "HASH") |
185 | ? shift |
186 | : ((@_ % 2) |
187 | ? $self->throw_exception( |
188 | "Odd number of arguments to search") |
189 | : {@_})) |
190 | : undef()); |
ff7bb7a1 |
191 | if (defined $where) { |
192 | $where = (defined $attrs->{where} |
ad3d2d7c |
193 | ? { '-and' => |
194 | [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ } |
195 | $where, $attrs->{where} ] } |
0a3c5b43 |
196 | : $where); |
ff7bb7a1 |
197 | $attrs->{where} = $where; |
198 | } |
0a3c5b43 |
199 | |
8839560b |
200 | if (defined $having) { |
201 | $having = (defined $attrs->{having} |
202 | ? { '-and' => |
203 | [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ } |
204 | $having, $attrs->{having} ] } |
205 | : $having); |
206 | $attrs->{having} = $having; |
207 | } |
208 | |
ff7bb7a1 |
209 | $rs = (ref $self)->new($self->result_source, $attrs); |
210 | } |
211 | else { |
212 | $rs = $self; |
213 | $rs->reset(); |
214 | } |
0a3c5b43 |
215 | return (wantarray ? $rs->all : $rs); |
216 | } |
217 | |
87f0da6a |
218 | =head2 search_literal |
219 | |
6009260a |
220 | my @obj = $rs->search_literal($literal_where_cond, @bind); |
221 | my $new_rs = $rs->search_literal($literal_where_cond, @bind); |
222 | |
223 | Pass a literal chunk of SQL to be added to the conditional part of the |
87f0da6a |
224 | resultset. |
6009260a |
225 | |
bfab575a |
226 | =cut |
fd9f5466 |
227 | |
6009260a |
228 | sub search_literal { |
229 | my ($self, $cond, @vals) = @_; |
230 | my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {}); |
231 | $attrs->{bind} = [ @{$self->{attrs}{bind}||[]}, @vals ]; |
232 | return $self->search(\$cond, $attrs); |
233 | } |
0a3c5b43 |
234 | |
87c4e602 |
235 | =head2 find |
236 | |
237 | =head3 Arguments: (@colvalues) | (\%cols, \%attrs?) |
87f0da6a |
238 | |
239 | Finds a row based on its primary key or unique constraint. For example: |
240 | |
87f0da6a |
241 | my $cd = $schema->resultset('CD')->find(5); |
242 | |
243 | Also takes an optional C<key> attribute, to search by a specific key or unique |
244 | constraint. For example: |
245 | |
fd9f5466 |
246 | my $cd = $schema->resultset('CD')->find( |
87f0da6a |
247 | { |
248 | artist => 'Massive Attack', |
249 | title => 'Mezzanine', |
250 | }, |
251 | { key => 'artist_title' } |
252 | ); |
253 | |
a33df5d4 |
254 | See also L</find_or_create> and L</update_or_create>. |
255 | |
87f0da6a |
256 | =cut |
716b3d29 |
257 | |
258 | sub find { |
259 | my ($self, @vals) = @_; |
260 | my $attrs = (@vals > 1 && ref $vals[$#vals] eq 'HASH' ? pop(@vals) : {}); |
87f0da6a |
261 | |
701da8c4 |
262 | my @cols = $self->result_source->primary_columns; |
87f0da6a |
263 | if (exists $attrs->{key}) { |
701da8c4 |
264 | my %uniq = $self->result_source->unique_constraints; |
87f0da6a |
265 | $self->( "Unknown key " . $attrs->{key} . " on " . $self->name ) |
266 | unless exists $uniq{$attrs->{key}}; |
267 | @cols = @{ $uniq{$attrs->{key}} }; |
268 | } |
269 | #use Data::Dumper; warn Dumper($attrs, @vals, @cols); |
701da8c4 |
270 | $self->throw_exception( "Can't find unless a primary key or unique constraint is defined" ) |
87f0da6a |
271 | unless @cols; |
272 | |
716b3d29 |
273 | my $query; |
274 | if (ref $vals[0] eq 'HASH') { |
01bc091e |
275 | $query = { %{$vals[0]} }; |
87f0da6a |
276 | } elsif (@cols == @vals) { |
716b3d29 |
277 | $query = {}; |
87f0da6a |
278 | @{$query}{@cols} = @vals; |
716b3d29 |
279 | } else { |
280 | $query = {@vals}; |
281 | } |
01bc091e |
282 | foreach (keys %$query) { |
283 | next if m/\./; |
284 | $query->{$self->{attrs}{alias}.'.'.$_} = delete $query->{$_}; |
285 | } |
716b3d29 |
286 | #warn Dumper($query); |
a04ab285 |
287 | return (keys %$attrs |
288 | ? $self->search($query,$attrs)->single |
289 | : $self->single($query)); |
716b3d29 |
290 | } |
291 | |
b52e9bf8 |
292 | =head2 search_related |
293 | |
294 | $rs->search_related('relname', $cond?, $attrs?); |
295 | |
a33df5d4 |
296 | Search the specified relationship. Optionally specify a condition for matching |
297 | records. |
298 | |
b52e9bf8 |
299 | =cut |
300 | |
6aeb9185 |
301 | sub search_related { |
64acc2bc |
302 | return shift->related_resultset(shift)->search(@_); |
6aeb9185 |
303 | } |
b52e9bf8 |
304 | |
bfab575a |
305 | =head2 cursor |
ee38fa40 |
306 | |
bfab575a |
307 | Returns a storage-driven cursor to the given resultset. |
ee38fa40 |
308 | |
309 | =cut |
310 | |
73f58123 |
311 | sub cursor { |
312 | my ($self) = @_; |
701da8c4 |
313 | my ($attrs) = $self->{attrs}; |
6aeb9185 |
314 | $attrs = { %$attrs }; |
73f58123 |
315 | return $self->{cursor} |
701da8c4 |
316 | ||= $self->result_source->storage->select($self->{from}, $attrs->{select}, |
73f58123 |
317 | $attrs->{where},$attrs); |
318 | } |
319 | |
a04ab285 |
320 | =head2 single |
321 | |
322 | Inflates the first result without creating a cursor |
323 | |
324 | =cut |
325 | |
326 | sub single { |
327 | my ($self, $extra) = @_; |
328 | my ($attrs) = $self->{attrs}; |
329 | $attrs = { %$attrs }; |
330 | if ($extra) { |
331 | if (defined $attrs->{where}) { |
332 | $attrs->{where} = { |
333 | '-and' |
334 | => [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ } |
335 | delete $attrs->{where}, $extra ] |
336 | }; |
337 | } else { |
338 | $attrs->{where} = $extra; |
339 | } |
340 | } |
341 | my @data = $self->result_source->storage->select_single( |
342 | $self->{from}, $attrs->{select}, |
343 | $attrs->{where},$attrs); |
344 | return (@data ? $self->_construct_object(@data) : ()); |
345 | } |
346 | |
347 | |
87f0da6a |
348 | =head2 search_like |
349 | |
a33df5d4 |
350 | Perform a search, but use C<LIKE> instead of equality as the condition. Note |
351 | that this is simply a convenience method; you most likely want to use |
352 | L</search> with specific operators. |
353 | |
354 | For more information, see L<DBIx::Class::Manual::Cookbook>. |
87f0da6a |
355 | |
356 | =cut |
58a4bd18 |
357 | |
358 | sub search_like { |
359 | my $class = shift; |
360 | my $attrs = { }; |
361 | if (@_ > 1 && ref $_[$#_] eq 'HASH') { |
362 | $attrs = pop(@_); |
363 | } |
364 | my $query = ref $_[0] eq "HASH" ? { %{shift()} }: {@_}; |
365 | $query->{$_} = { 'like' => $query->{$_} } for keys %$query; |
366 | return $class->search($query, { %$attrs }); |
367 | } |
368 | |
87c4e602 |
369 | =head2 slice |
370 | |
371 | =head3 Arguments: ($first, $last) |
ee38fa40 |
372 | |
bfab575a |
373 | Returns a subset of elements from the resultset. |
ee38fa40 |
374 | |
375 | =cut |
376 | |
89c0a5a2 |
377 | sub slice { |
378 | my ($self, $min, $max) = @_; |
379 | my $attrs = { %{ $self->{attrs} || {} } }; |
6aeb9185 |
380 | $attrs->{offset} ||= 0; |
381 | $attrs->{offset} += $min; |
89c0a5a2 |
382 | $attrs->{rows} = ($max ? ($max - $min + 1) : 1); |
701da8c4 |
383 | my $slice = (ref $self)->new($self->result_source, $attrs); |
89c0a5a2 |
384 | return (wantarray ? $slice->all : $slice); |
385 | } |
386 | |
87f0da6a |
387 | =head2 next |
ee38fa40 |
388 | |
a33df5d4 |
389 | Returns the next element in the resultset (C<undef> is there is none). |
390 | |
391 | Can be used to efficiently iterate over records in the resultset: |
392 | |
393 | my $rs = $schema->resultset('CD')->search({}); |
394 | while (my $cd = $rs->next) { |
395 | print $cd->title; |
396 | } |
ee38fa40 |
397 | |
398 | =cut |
399 | |
89c0a5a2 |
400 | sub next { |
401 | my ($self) = @_; |
3e0e9e27 |
402 | my $cache; |
403 | if( @{$cache = $self->{all_cache} || []}) { |
64acc2bc |
404 | $self->{all_cache_position} ||= 0; |
405 | my $obj = $cache->[$self->{all_cache_position}]; |
406 | $self->{all_cache_position}++; |
407 | return $obj; |
408 | } |
3e0e9e27 |
409 | if ($self->{attrs}{cache}) { |
0f66a01b |
410 | $self->{all_cache_position} = 1; |
3e0e9e27 |
411 | return ($self->all)[0]; |
412 | } |
0f66a01b |
413 | my @row = (exists $self->{stashed_row} |
414 | ? @{delete $self->{stashed_row}} |
415 | : $self->cursor->next); |
a953d8d9 |
416 | # warn Dumper(\@row); use Data::Dumper; |
89c0a5a2 |
417 | return unless (@row); |
c7ce65e6 |
418 | return $self->_construct_object(@row); |
419 | } |
420 | |
421 | sub _construct_object { |
422 | my ($self, @row) = @_; |
b3e8ac9b |
423 | my @as = @{ $self->{attrs}{as} }; |
0f66a01b |
424 | |
425 | my $info = $self->_collapse_result(\@as, \@row); |
426 | |
a50bcd52 |
427 | my $new = $self->result_class->inflate_result($self->result_source, @$info); |
0f66a01b |
428 | |
33ce49d6 |
429 | $new = $self->{attrs}{record_filter}->($new) |
430 | if exists $self->{attrs}{record_filter}; |
f9cc31dd |
431 | |
33ce49d6 |
432 | return $new; |
89c0a5a2 |
433 | } |
434 | |
0f66a01b |
435 | sub _collapse_result { |
436 | my ($self, $as, $row, $prefix) = @_; |
437 | |
438 | my %const; |
439 | |
440 | my @copy = @$row; |
5a5bec6c |
441 | foreach my $this_as (@$as) { |
442 | my $val = shift @copy; |
443 | if (defined $prefix) { |
444 | if ($this_as =~ m/^\Q${prefix}.\E(.+)$/) { |
445 | my $remain = $1; |
446 | $remain =~ /^(?:(.*)\.)?([^\.]+)$/; |
447 | $const{$1||''}{$2} = $val; |
448 | } |
449 | } else { |
450 | $this_as =~ /^(?:(.*)\.)?([^\.]+)$/; |
451 | $const{$1||''}{$2} = $val; |
0f66a01b |
452 | } |
0f66a01b |
453 | } |
454 | |
0f66a01b |
455 | my $info = [ {}, {} ]; |
456 | foreach my $key (keys %const) { |
457 | if (length $key) { |
458 | my $target = $info; |
459 | my @parts = split(/\./, $key); |
460 | foreach my $p (@parts) { |
461 | $target = $target->[1]->{$p} ||= []; |
462 | } |
463 | $target->[0] = $const{$key}; |
464 | } else { |
465 | $info->[0] = $const{$key}; |
466 | } |
467 | } |
468 | |
5a5bec6c |
469 | my @collapse = (defined($prefix) |
470 | ? (map { (m/^\Q${prefix}.\E(.+)$/ ? ($1) : ()); } |
471 | keys %{$self->{collapse}}) |
472 | : keys %{$self->{collapse}}); |
473 | if (@collapse) { |
474 | my ($c) = sort { length $a <=> length $b } @collapse; |
0f66a01b |
475 | my $target = $info; |
0f66a01b |
476 | foreach my $p (split(/\./, $c)) { |
5a5bec6c |
477 | $target = $target->[1]->{$p} ||= []; |
0f66a01b |
478 | } |
5a5bec6c |
479 | my $c_prefix = (defined($prefix) ? "${prefix}.${c}" : $c); |
480 | my @co_key = @{$self->{collapse}{$c_prefix}}; |
0f66a01b |
481 | my %co_check = map { ($_, $target->[0]->{$_}); } @co_key; |
5a5bec6c |
482 | my $tree = $self->_collapse_result($as, $row, $c_prefix); |
0f66a01b |
483 | my (@final, @raw); |
5a5bec6c |
484 | while ( !(grep { |
485 | !defined($tree->[0]->{$_}) |
486 | || $co_check{$_} ne $tree->[0]->{$_} |
487 | } @co_key) ) { |
0f66a01b |
488 | push(@final, $tree); |
489 | last unless (@raw = $self->cursor->next); |
490 | $row = $self->{stashed_row} = \@raw; |
5a5bec6c |
491 | $tree = $self->_collapse_result($as, $row, $c_prefix); |
492 | #warn Data::Dumper::Dumper($tree, $row); |
0f66a01b |
493 | } |
494 | @{$target} = @final; |
0f66a01b |
495 | } |
496 | |
0f66a01b |
497 | return $info; |
498 | } |
499 | |
87c4e602 |
500 | =head2 result_source |
701da8c4 |
501 | |
502 | Returns a reference to the result source for this recordset. |
503 | |
504 | =cut |
505 | |
506 | |
bfab575a |
507 | =head2 count |
ee38fa40 |
508 | |
bfab575a |
509 | Performs an SQL C<COUNT> with the same query as the resultset was built |
6009260a |
510 | with to find the number of elements. If passed arguments, does a search |
511 | on the resultset and counts the results of that. |
ee38fa40 |
512 | |
bda4c2b8 |
513 | Note: When using C<count> with C<group_by>, L<DBIX::Class> emulates C<GROUP BY> |
514 | using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do |
515 | not support C<DISTINCT> with multiple columns. If you are using such a |
516 | database, you should only use columns from the main table in your C<group_by> |
517 | clause. |
518 | |
ee38fa40 |
519 | =cut |
520 | |
89c0a5a2 |
521 | sub count { |
6009260a |
522 | my $self = shift; |
523 | return $self->search(@_)->count if @_ && defined $_[0]; |
6aeb9185 |
524 | unless (defined $self->{count}) { |
64acc2bc |
525 | return scalar @{ $self->get_cache } |
526 | if @{ $self->get_cache }; |
15c382be |
527 | my $group_by; |
528 | my $select = { 'count' => '*' }; |
8839560b |
529 | my $attrs = { %{ $self->{attrs} } }; |
530 | if( $group_by = delete $attrs->{group_by} ) { |
531 | delete $attrs->{having}; |
dec2517f |
532 | my @distinct = (ref $group_by ? @$group_by : ($group_by)); |
15c382be |
533 | # todo: try CONCAT for multi-column pk |
534 | my @pk = $self->result_source->primary_columns; |
535 | if( scalar(@pk) == 1 ) { |
536 | my $pk = shift(@pk); |
8839560b |
537 | my $alias = $attrs->{alias}; |
15c382be |
538 | my $re = qr/^($alias\.)?$pk$/; |
d0f1e63f |
539 | foreach my $column ( @distinct) { |
15c382be |
540 | if( $column =~ $re ) { |
541 | @distinct = ( $column ); |
542 | last; |
543 | } |
544 | } |
545 | } |
546 | |
547 | $select = { count => { 'distinct' => \@distinct } }; |
548 | #use Data::Dumper; die Dumper $select; |
549 | } |
550 | |
8839560b |
551 | $attrs->{select} = $select; |
552 | $attrs->{as} = [ 'count' ]; |
ea20d0fd |
553 | # offset, order by and page are not needed to count. record_filter is cdbi |
554 | delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/; |
3c5b25c5 |
555 | |
701da8c4 |
556 | ($self->{count}) = (ref $self)->new($self->result_source, $attrs)->cursor->next; |
3c5b25c5 |
557 | } |
558 | return 0 unless $self->{count}; |
6aeb9185 |
559 | my $count = $self->{count}; |
560 | $count -= $self->{attrs}{offset} if $self->{attrs}{offset}; |
561 | $count = $self->{attrs}{rows} if |
562 | ($self->{attrs}{rows} && $self->{attrs}{rows} < $count); |
563 | return $count; |
89c0a5a2 |
564 | } |
565 | |
bfab575a |
566 | =head2 count_literal |
6009260a |
567 | |
a33df5d4 |
568 | Calls L</search_literal> with the passed arguments, then L</count>. |
6009260a |
569 | |
570 | =cut |
571 | |
572 | sub count_literal { shift->search_literal(@_)->count; } |
573 | |
bfab575a |
574 | =head2 all |
ee38fa40 |
575 | |
bfab575a |
576 | Returns all elements in the resultset. Called implictly if the resultset |
577 | is returned in list context. |
ee38fa40 |
578 | |
579 | =cut |
580 | |
89c0a5a2 |
581 | sub all { |
582 | my ($self) = @_; |
64acc2bc |
583 | return @{ $self->get_cache } |
584 | if @{ $self->get_cache }; |
5a5bec6c |
585 | |
586 | my @obj; |
587 | |
588 | if (keys %{$self->{collapse}}) { |
589 | # Using $self->cursor->all is really just an optimisation. |
590 | # If we're collapsing has_many prefetches it probably makes |
591 | # very little difference, and this is cleaner than hacking |
592 | # _construct_object to survive the approach |
593 | my @row; |
594 | $self->cursor->reset; |
595 | while (@row = $self->cursor->next) { |
596 | push(@obj, $self->_construct_object(@row)); |
597 | } |
598 | } else { |
599 | @obj = map { $self->_construct_object(@$_); } |
600 | $self->cursor->all; |
601 | } |
602 | |
64acc2bc |
603 | if( $self->{attrs}->{cache} ) { |
64acc2bc |
604 | $self->set_cache( \@obj ); |
64acc2bc |
605 | } |
5a5bec6c |
606 | |
607 | return @obj; |
89c0a5a2 |
608 | } |
609 | |
bfab575a |
610 | =head2 reset |
ee38fa40 |
611 | |
bfab575a |
612 | Resets the resultset's cursor, so you can iterate through the elements again. |
ee38fa40 |
613 | |
614 | =cut |
615 | |
89c0a5a2 |
616 | sub reset { |
617 | my ($self) = @_; |
64acc2bc |
618 | $self->{all_cache_position} = 0; |
73f58123 |
619 | $self->cursor->reset; |
89c0a5a2 |
620 | return $self; |
621 | } |
622 | |
bfab575a |
623 | =head2 first |
ee38fa40 |
624 | |
bfab575a |
625 | Resets the resultset and returns the first element. |
ee38fa40 |
626 | |
627 | =cut |
628 | |
89c0a5a2 |
629 | sub first { |
630 | return $_[0]->reset->next; |
631 | } |
632 | |
87c4e602 |
633 | =head2 update |
634 | |
635 | =head3 Arguments: (\%values) |
c01ab172 |
636 | |
a33df5d4 |
637 | Sets the specified columns in the resultset to the supplied values. |
c01ab172 |
638 | |
639 | =cut |
640 | |
641 | sub update { |
642 | my ($self, $values) = @_; |
701da8c4 |
643 | $self->throw_exception("Values for update must be a hash") unless ref $values eq 'HASH'; |
644 | return $self->result_source->storage->update( |
645 | $self->result_source->from, $values, $self->{cond}); |
c01ab172 |
646 | } |
647 | |
87c4e602 |
648 | =head2 update_all |
649 | |
650 | =head3 Arguments: (\%values) |
c01ab172 |
651 | |
a33df5d4 |
652 | Fetches all objects and updates them one at a time. Note that C<update_all> |
653 | will run cascade triggers while L</update> will not. |
c01ab172 |
654 | |
655 | =cut |
656 | |
657 | sub update_all { |
658 | my ($self, $values) = @_; |
701da8c4 |
659 | $self->throw_exception("Values for update must be a hash") unless ref $values eq 'HASH'; |
c01ab172 |
660 | foreach my $obj ($self->all) { |
661 | $obj->set_columns($values)->update; |
662 | } |
663 | return 1; |
664 | } |
665 | |
bfab575a |
666 | =head2 delete |
ee38fa40 |
667 | |
c01ab172 |
668 | Deletes the contents of the resultset from its result source. |
ee38fa40 |
669 | |
670 | =cut |
671 | |
28927b50 |
672 | sub delete { |
89c0a5a2 |
673 | my ($self) = @_; |
ca4b5ab7 |
674 | my $del = {}; |
675 | $self->throw_exception("Can't delete on resultset with condition unless hash or array") |
676 | unless (ref($self->{cond}) eq 'HASH' || ref($self->{cond}) eq 'ARRAY'); |
677 | if (ref $self->{cond} eq 'ARRAY') { |
678 | $del = [ map { my %hash; |
679 | foreach my $key (keys %{$_}) { |
680 | $key =~ /([^\.]+)$/; |
681 | $hash{$1} = $_->{$key}; |
682 | }; \%hash; } @{$self->{cond}} ]; |
683 | } elsif ((keys %{$self->{cond}})[0] eq '-and') { |
684 | $del->{-and} = [ map { my %hash; |
685 | foreach my $key (keys %{$_}) { |
686 | $key =~ /([^\.]+)$/; |
687 | $hash{$1} = $_->{$key}; |
688 | }; \%hash; } @{$self->{cond}{-and}} ]; |
689 | } else { |
690 | foreach my $key (keys %{$self->{cond}}) { |
691 | $key =~ /([^\.]+)$/; |
692 | $del->{$1} = $self->{cond}{$key}; |
693 | } |
694 | } |
695 | $self->result_source->storage->delete($self->result_source->from, $del); |
89c0a5a2 |
696 | return 1; |
697 | } |
698 | |
c01ab172 |
699 | =head2 delete_all |
700 | |
a33df5d4 |
701 | Fetches all objects and deletes them one at a time. Note that C<delete_all> |
702 | will run cascade triggers while L</delete> will not. |
c01ab172 |
703 | |
704 | =cut |
705 | |
706 | sub delete_all { |
707 | my ($self) = @_; |
708 | $_->delete for $self->all; |
709 | return 1; |
710 | } |
28927b50 |
711 | |
bfab575a |
712 | =head2 pager |
ee38fa40 |
713 | |
714 | Returns a L<Data::Page> object for the current resultset. Only makes |
a33df5d4 |
715 | sense for queries with a C<page> attribute. |
ee38fa40 |
716 | |
717 | =cut |
718 | |
3c5b25c5 |
719 | sub pager { |
720 | my ($self) = @_; |
721 | my $attrs = $self->{attrs}; |
701da8c4 |
722 | $self->throw_exception("Can't create pager for non-paged rs") unless $self->{page}; |
6aeb9185 |
723 | $attrs->{rows} ||= 10; |
724 | $self->count; |
725 | return $self->{pager} ||= Data::Page->new( |
93b004d3 |
726 | $self->{count}, $attrs->{rows}, $self->{page}); |
3c5b25c5 |
727 | } |
728 | |
87c4e602 |
729 | =head2 page |
730 | |
731 | =head3 Arguments: ($page_num) |
ee38fa40 |
732 | |
bfab575a |
733 | Returns a new resultset for the specified page. |
ee38fa40 |
734 | |
735 | =cut |
736 | |
3c5b25c5 |
737 | sub page { |
738 | my ($self, $page) = @_; |
6aeb9185 |
739 | my $attrs = { %{$self->{attrs}} }; |
3c5b25c5 |
740 | $attrs->{page} = $page; |
701da8c4 |
741 | return (ref $self)->new($self->result_source, $attrs); |
fea3d045 |
742 | } |
743 | |
87c4e602 |
744 | =head2 new_result |
745 | |
746 | =head3 Arguments: (\%vals) |
fea3d045 |
747 | |
87f0da6a |
748 | Creates a result in the resultset's result class. |
fea3d045 |
749 | |
750 | =cut |
751 | |
752 | sub new_result { |
753 | my ($self, $values) = @_; |
701da8c4 |
754 | $self->throw_exception( "new_result needs a hash" ) |
fea3d045 |
755 | unless (ref $values eq 'HASH'); |
701da8c4 |
756 | $self->throw_exception( "Can't abstract implicit construct, condition not a hash" ) |
fea3d045 |
757 | if ($self->{cond} && !(ref $self->{cond} eq 'HASH')); |
758 | my %new = %$values; |
759 | my $alias = $self->{attrs}{alias}; |
760 | foreach my $key (keys %{$self->{cond}||{}}) { |
761 | $new{$1} = $self->{cond}{$key} if ($key =~ m/^(?:$alias\.)?([^\.]+)$/); |
762 | } |
a50bcd52 |
763 | my $obj = $self->result_class->new(\%new); |
701da8c4 |
764 | $obj->result_source($self->result_source) if $obj->can('result_source'); |
097d3227 |
765 | $obj; |
fea3d045 |
766 | } |
767 | |
87c4e602 |
768 | =head2 create |
769 | |
770 | =head3 Arguments: (\%vals) |
fea3d045 |
771 | |
87f0da6a |
772 | Inserts a record into the resultset and returns the object. |
fea3d045 |
773 | |
a33df5d4 |
774 | Effectively a shortcut for C<< ->new_result(\%vals)->insert >>. |
fea3d045 |
775 | |
776 | =cut |
777 | |
778 | sub create { |
779 | my ($self, $attrs) = @_; |
701da8c4 |
780 | $self->throw_exception( "create needs a hashref" ) unless ref $attrs eq 'HASH'; |
fea3d045 |
781 | return $self->new_result($attrs)->insert; |
3c5b25c5 |
782 | } |
783 | |
87c4e602 |
784 | =head2 find_or_create |
785 | |
786 | =head3 Arguments: (\%vals, \%attrs?) |
87f0da6a |
787 | |
788 | $class->find_or_create({ key => $val, ... }); |
c2b15ecc |
789 | |
fd9f5466 |
790 | Searches for a record matching the search condition; if it doesn't find one, |
791 | creates one and returns that instead. |
87f0da6a |
792 | |
87f0da6a |
793 | my $cd = $schema->resultset('CD')->find_or_create({ |
794 | cdid => 5, |
795 | artist => 'Massive Attack', |
796 | title => 'Mezzanine', |
797 | year => 2005, |
798 | }); |
799 | |
800 | Also takes an optional C<key> attribute, to search by a specific key or unique |
801 | constraint. For example: |
802 | |
803 | my $cd = $schema->resultset('CD')->find_or_create( |
804 | { |
805 | artist => 'Massive Attack', |
806 | title => 'Mezzanine', |
807 | }, |
808 | { key => 'artist_title' } |
809 | ); |
810 | |
811 | See also L</find> and L</update_or_create>. |
812 | |
c2b15ecc |
813 | =cut |
814 | |
815 | sub find_or_create { |
816 | my $self = shift; |
87f0da6a |
817 | my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {}); |
818 | my $hash = ref $_[0] eq "HASH" ? shift : {@_}; |
819 | my $exists = $self->find($hash, $attrs); |
c2b15ecc |
820 | return defined($exists) ? $exists : $self->create($hash); |
821 | } |
822 | |
87f0da6a |
823 | =head2 update_or_create |
824 | |
825 | $class->update_or_create({ key => $val, ... }); |
826 | |
827 | First, search for an existing row matching one of the unique constraints |
828 | (including the primary key) on the source of this resultset. If a row is |
829 | found, update it with the other given column values. Otherwise, create a new |
830 | row. |
831 | |
832 | Takes an optional C<key> attribute to search on a specific unique constraint. |
833 | For example: |
834 | |
835 | # In your application |
836 | my $cd = $schema->resultset('CD')->update_or_create( |
837 | { |
838 | artist => 'Massive Attack', |
839 | title => 'Mezzanine', |
840 | year => 1998, |
841 | }, |
842 | { key => 'artist_title' } |
843 | ); |
844 | |
845 | If no C<key> is specified, it searches on all unique constraints defined on the |
846 | source, including the primary key. |
847 | |
848 | If the C<key> is specified as C<primary>, search only on the primary key. |
849 | |
a33df5d4 |
850 | See also L</find> and L</find_or_create>. |
851 | |
87f0da6a |
852 | =cut |
853 | |
854 | sub update_or_create { |
855 | my $self = shift; |
856 | |
857 | my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {}); |
858 | my $hash = ref $_[0] eq "HASH" ? shift : {@_}; |
859 | |
701da8c4 |
860 | my %unique_constraints = $self->result_source->unique_constraints; |
87f0da6a |
861 | my @constraint_names = (exists $attrs->{key} |
862 | ? ($attrs->{key}) |
863 | : keys %unique_constraints); |
864 | |
865 | my @unique_hashes; |
866 | foreach my $name (@constraint_names) { |
867 | my @unique_cols = @{ $unique_constraints{$name} }; |
868 | my %unique_hash = |
869 | map { $_ => $hash->{$_} } |
870 | grep { exists $hash->{$_} } |
871 | @unique_cols; |
872 | |
873 | push @unique_hashes, \%unique_hash |
874 | if (scalar keys %unique_hash == scalar @unique_cols); |
875 | } |
876 | |
877 | my $row; |
878 | if (@unique_hashes) { |
879 | $row = $self->search(\@unique_hashes, { rows => 1 })->first; |
880 | if ($row) { |
881 | $row->set_columns($hash); |
882 | $row->update; |
883 | } |
884 | } |
885 | |
886 | unless ($row) { |
887 | $row = $self->create($hash); |
888 | } |
889 | |
890 | return $row; |
891 | } |
892 | |
64acc2bc |
893 | =head2 get_cache |
894 | |
895 | Gets the contents of the cache for the resultset. |
896 | |
897 | =cut |
898 | |
899 | sub get_cache { |
900 | my $self = shift; |
901 | return $self->{all_cache} || []; |
902 | } |
903 | |
904 | =head2 set_cache |
905 | |
906 | Sets the contents of the cache for the resultset. Expects an arrayref of objects of the same class as those produced by the resultset. |
907 | |
908 | =cut |
909 | |
910 | sub set_cache { |
911 | my ( $self, $data ) = @_; |
912 | $self->throw_exception("set_cache requires an arrayref") |
913 | if ref $data ne 'ARRAY'; |
a50bcd52 |
914 | my $result_class = $self->result_class; |
64acc2bc |
915 | foreach( @$data ) { |
916 | $self->throw_exception("cannot cache object of type '$_', expected '$result_class'") |
917 | if ref $_ ne $result_class; |
918 | } |
919 | $self->{all_cache} = $data; |
920 | } |
921 | |
922 | =head2 clear_cache |
923 | |
924 | Clears the cache for the resultset. |
925 | |
926 | =cut |
927 | |
928 | sub clear_cache { |
929 | my $self = shift; |
930 | $self->set_cache([]); |
931 | } |
932 | |
933 | =head2 related_resultset |
934 | |
935 | Returns a related resultset for the supplied relationship name. |
936 | |
937 | $rs = $rs->related_resultset('foo'); |
938 | |
939 | =cut |
940 | |
941 | sub related_resultset { |
942 | my ( $self, $rel, @rest ) = @_; |
943 | $self->{related_resultsets} ||= {}; |
944 | my $resultsets = $self->{related_resultsets}; |
945 | if( !exists $resultsets->{$rel} ) { |
946 | #warn "fetching related resultset for rel '$rel'"; |
947 | my $rel_obj = $self->result_source->relationship_info($rel); |
948 | $self->throw_exception( |
949 | "search_related: result source '" . $self->result_source->name . |
950 | "' has no such relationship ${rel}") |
951 | unless $rel_obj; #die Dumper $self->{attrs}; |
a86b1efe |
952 | my $rs = $self->search(undef, { join => $rel }); |
953 | #if( $self->{attrs}->{cache} ) { |
954 | # $rs = $self->search(undef); |
955 | #} |
956 | #else { |
957 | #} |
64acc2bc |
958 | #use Data::Dumper; die Dumper $rs->{attrs};#$rs = $self->search( undef ); |
959 | #use Data::Dumper; warn Dumper $self->{attrs}, Dumper $rs->{attrs}; |
960 | my $alias = (defined $rs->{attrs}{seen_join}{$rel} |
961 | && $rs->{attrs}{seen_join}{$rel} > 1 |
962 | ? join('_', $rel, $rs->{attrs}{seen_join}{$rel}) |
963 | : $rel); |
964 | $resultsets->{$rel} = |
965 | $self->result_source->schema->resultset($rel_obj->{class} |
966 | )->search( undef, |
967 | { %{$rs->{attrs}}, |
968 | alias => $alias, |
969 | select => undef(), |
970 | as => undef() } |
971 | )->search(@rest); |
972 | } |
973 | return $resultsets->{$rel}; |
974 | } |
975 | |
701da8c4 |
976 | =head2 throw_exception |
977 | |
978 | See Schema's throw_exception |
979 | |
980 | =cut |
981 | |
982 | sub throw_exception { |
983 | my $self=shift; |
984 | $self->result_source->schema->throw_exception(@_); |
985 | } |
986 | |
40dbc108 |
987 | =head1 ATTRIBUTES |
076652e8 |
988 | |
a33df5d4 |
989 | The resultset takes various attributes that modify its behavior. Here's an |
990 | overview of them: |
bfab575a |
991 | |
992 | =head2 order_by |
076652e8 |
993 | |
a33df5d4 |
994 | Which column(s) to order the results by. This is currently passed through |
995 | directly to SQL, so you can give e.g. C<foo DESC> for a descending order. |
076652e8 |
996 | |
87c4e602 |
997 | =head2 cols |
998 | |
999 | =head3 Arguments: (arrayref) |
976f3686 |
1000 | |
a33df5d4 |
1001 | Shortcut to request a particular set of columns to be retrieved. Adds |
1002 | C<me.> onto the start of any column without a C<.> in it and sets C<select> |
1003 | from that, then auto-populates C<as> from C<select> as normal. |
976f3686 |
1004 | |
87c4e602 |
1005 | =head2 include_columns |
1006 | |
1007 | =head3 Arguments: (arrayref) |
5ac6a044 |
1008 | |
1009 | Shortcut to include additional columns in the returned results - for example |
1010 | |
1011 | { include_columns => ['foo.name'], join => ['foo'] } |
1012 | |
1013 | would add a 'name' column to the information passed to object inflation |
1014 | |
87c4e602 |
1015 | =head2 select |
1016 | |
1017 | =head3 Arguments: (arrayref) |
976f3686 |
1018 | |
4a28c340 |
1019 | Indicates which columns should be selected from the storage. You can use |
1020 | column names, or in the case of RDBMS back ends, function or stored procedure |
1021 | names: |
1022 | |
1023 | $rs = $schema->resultset('Foo')->search( |
1024 | {}, |
1025 | { |
cf7b40ed |
1026 | select => [ |
4a28c340 |
1027 | 'column_name', |
1028 | { count => 'column_to_count' }, |
1029 | { sum => 'column_to_sum' } |
cf7b40ed |
1030 | ] |
4a28c340 |
1031 | } |
1032 | ); |
1033 | |
1034 | When you use function/stored procedure names and do not supply an C<as> |
1035 | attribute, the column names returned are storage-dependent. E.g. MySQL would |
1036 | return a column named C<count(column_to_count)> in the above example. |
976f3686 |
1037 | |
87c4e602 |
1038 | =head2 as |
1039 | |
1040 | =head3 Arguments: (arrayref) |
076652e8 |
1041 | |
4a28c340 |
1042 | Indicates column names for object inflation. This is used in conjunction with |
1043 | C<select>, usually when C<select> contains one or more function or stored |
1044 | procedure names: |
1045 | |
1046 | $rs = $schema->resultset('Foo')->search( |
1047 | {}, |
1048 | { |
cf7b40ed |
1049 | select => [ |
4a28c340 |
1050 | 'column1', |
1051 | { count => 'column2' } |
cf7b40ed |
1052 | ], |
4a28c340 |
1053 | as => [qw/ column1 column2_count /] |
1054 | } |
1055 | ); |
1056 | |
1057 | my $foo = $rs->first(); # get the first Foo |
1058 | |
1059 | If the object against which the search is performed already has an accessor |
1060 | matching a column name specified in C<as>, the value can be retrieved using |
1061 | the accessor as normal: |
1062 | |
1063 | my $column1 = $foo->column1(); |
1064 | |
1065 | If on the other hand an accessor does not exist in the object, you need to |
1066 | use C<get_column> instead: |
1067 | |
1068 | my $column2_count = $foo->get_column('column2_count'); |
1069 | |
1070 | You can create your own accessors if required - see |
1071 | L<DBIx::Class::Manual::Cookbook> for details. |
ee38fa40 |
1072 | |
bfab575a |
1073 | =head2 join |
ee38fa40 |
1074 | |
a33df5d4 |
1075 | Contains a list of relationships that should be joined for this query. For |
1076 | example: |
1077 | |
1078 | # Get CDs by Nine Inch Nails |
1079 | my $rs = $schema->resultset('CD')->search( |
1080 | { 'artist.name' => 'Nine Inch Nails' }, |
1081 | { join => 'artist' } |
1082 | ); |
1083 | |
1084 | Can also contain a hash reference to refer to the other relation's relations. |
1085 | For example: |
1086 | |
1087 | package MyApp::Schema::Track; |
1088 | use base qw/DBIx::Class/; |
1089 | __PACKAGE__->table('track'); |
1090 | __PACKAGE__->add_columns(qw/trackid cd position title/); |
1091 | __PACKAGE__->set_primary_key('trackid'); |
1092 | __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD'); |
1093 | 1; |
1094 | |
1095 | # In your application |
1096 | my $rs = $schema->resultset('Artist')->search( |
1097 | { 'track.title' => 'Teardrop' }, |
1098 | { |
1099 | join => { cd => 'track' }, |
1100 | order_by => 'artist.name', |
1101 | } |
1102 | ); |
1103 | |
2cb360cc |
1104 | If the same join is supplied twice, it will be aliased to <rel>_2 (and |
1105 | similarly for a third time). For e.g. |
1106 | |
1107 | my $rs = $schema->resultset('Artist')->search( |
1108 | { 'cds.title' => 'Foo', |
1109 | 'cds_2.title' => 'Bar' }, |
1110 | { join => [ qw/cds cds/ ] }); |
1111 | |
1112 | will return a set of all artists that have both a cd with title Foo and a cd |
1113 | with title Bar. |
1114 | |
1115 | If you want to fetch related objects from other tables as well, see C<prefetch> |
ae1c90a1 |
1116 | below. |
ee38fa40 |
1117 | |
87c4e602 |
1118 | =head2 prefetch |
1119 | |
1120 | =head3 Arguments: arrayref/hashref |
ee38fa40 |
1121 | |
ae1c90a1 |
1122 | Contains one or more relationships that should be fetched along with the main |
bfab575a |
1123 | query (when they are accessed afterwards they will have already been |
a33df5d4 |
1124 | "prefetched"). This is useful for when you know you will need the related |
ae1c90a1 |
1125 | objects, because it saves at least one query: |
1126 | |
1127 | my $rs = $schema->resultset('Tag')->search( |
1128 | {}, |
1129 | { |
1130 | prefetch => { |
1131 | cd => 'artist' |
1132 | } |
1133 | } |
1134 | ); |
1135 | |
1136 | The initial search results in SQL like the following: |
1137 | |
1138 | SELECT tag.*, cd.*, artist.* FROM tag |
1139 | JOIN cd ON tag.cd = cd.cdid |
1140 | JOIN artist ON cd.artist = artist.artistid |
1141 | |
1142 | L<DBIx::Class> has no need to go back to the database when we access the |
1143 | C<cd> or C<artist> relationships, which saves us two SQL statements in this |
1144 | case. |
1145 | |
2cb360cc |
1146 | Simple prefetches will be joined automatically, so there is no need |
1147 | for a C<join> attribute in the above search. If you're prefetching to |
1148 | depth (e.g. { cd => { artist => 'label' } or similar), you'll need to |
1149 | specify the join as well. |
ae1c90a1 |
1150 | |
1151 | C<prefetch> can be used with the following relationship types: C<belongs_to>, |
2cb360cc |
1152 | C<has_one> (or if you're using C<add_relationship>, any relationship declared |
1153 | with an accessor type of 'single' or 'filter'). |
ee38fa40 |
1154 | |
87c4e602 |
1155 | =head2 from |
1156 | |
1157 | =head3 Arguments: (arrayref) |
ee38fa40 |
1158 | |
4a28c340 |
1159 | The C<from> attribute gives you manual control over the C<FROM> clause of SQL |
1160 | statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN> |
1161 | clauses. |
ee38fa40 |
1162 | |
a33df5d4 |
1163 | NOTE: Use this on your own risk. This allows you to shoot off your foot! |
4a28c340 |
1164 | C<join> will usually do what you need and it is strongly recommended that you |
1165 | avoid using C<from> unless you cannot achieve the desired result using C<join>. |
1166 | |
1167 | In simple terms, C<from> works as follows: |
1168 | |
1169 | [ |
1170 | { <alias> => <table>, -join-type => 'inner|left|right' } |
1171 | [] # nested JOIN (optional) |
1172 | { <table.column> = <foreign_table.foreign_key> } |
1173 | ] |
1174 | |
1175 | JOIN |
1176 | <alias> <table> |
1177 | [JOIN ...] |
1178 | ON <table.column> = <foreign_table.foreign_key> |
1179 | |
1180 | An easy way to follow the examples below is to remember the following: |
1181 | |
1182 | Anything inside "[]" is a JOIN |
1183 | Anything inside "{}" is a condition for the enclosing JOIN |
1184 | |
1185 | The following examples utilize a "person" table in a family tree application. |
1186 | In order to express parent->child relationships, this table is self-joined: |
1187 | |
1188 | # Person->belongs_to('father' => 'Person'); |
1189 | # Person->belongs_to('mother' => 'Person'); |
1190 | |
1191 | C<from> can be used to nest joins. Here we return all children with a father, |
1192 | then search against all mothers of those children: |
1193 | |
1194 | $rs = $schema->resultset('Person')->search( |
1195 | {}, |
1196 | { |
1197 | alias => 'mother', # alias columns in accordance with "from" |
1198 | from => [ |
1199 | { mother => 'person' }, |
1200 | [ |
1201 | [ |
1202 | { child => 'person' }, |
1203 | [ |
1204 | { father => 'person' }, |
1205 | { 'father.person_id' => 'child.father_id' } |
1206 | ] |
1207 | ], |
1208 | { 'mother.person_id' => 'child.mother_id' } |
fd9f5466 |
1209 | ], |
4a28c340 |
1210 | ] |
1211 | }, |
1212 | ); |
1213 | |
1214 | # Equivalent SQL: |
1215 | # SELECT mother.* FROM person mother |
1216 | # JOIN ( |
1217 | # person child |
1218 | # JOIN person father |
1219 | # ON ( father.person_id = child.father_id ) |
1220 | # ) |
1221 | # ON ( mother.person_id = child.mother_id ) |
1222 | |
1223 | The type of any join can be controlled manually. To search against only people |
1224 | with a father in the person table, we could explicitly use C<INNER JOIN>: |
1225 | |
1226 | $rs = $schema->resultset('Person')->search( |
1227 | {}, |
1228 | { |
1229 | alias => 'child', # alias columns in accordance with "from" |
1230 | from => [ |
1231 | { child => 'person' }, |
1232 | [ |
1233 | { father => 'person', -join-type => 'inner' }, |
1234 | { 'father.id' => 'child.father_id' } |
1235 | ], |
1236 | ] |
1237 | }, |
1238 | ); |
1239 | |
1240 | # Equivalent SQL: |
1241 | # SELECT child.* FROM person child |
1242 | # INNER JOIN person father ON child.father_id = father.id |
ee38fa40 |
1243 | |
bfab575a |
1244 | =head2 page |
076652e8 |
1245 | |
a33df5d4 |
1246 | For a paged resultset, specifies which page to retrieve. Leave unset |
bfab575a |
1247 | for an unpaged resultset. |
076652e8 |
1248 | |
bfab575a |
1249 | =head2 rows |
076652e8 |
1250 | |
4a28c340 |
1251 | For a paged resultset, how many rows per page: |
1252 | |
1253 | rows => 10 |
1254 | |
1255 | Can also be used to simulate an SQL C<LIMIT>. |
076652e8 |
1256 | |
87c4e602 |
1257 | =head2 group_by |
1258 | |
1259 | =head3 Arguments: (arrayref) |
54540863 |
1260 | |
bda4c2b8 |
1261 | A arrayref of columns to group by. Can include columns of joined tables. |
54540863 |
1262 | |
675ce4a6 |
1263 | group_by => [qw/ column1 column2 ... /] |
1264 | |
54540863 |
1265 | =head2 distinct |
1266 | |
a33df5d4 |
1267 | Set to 1 to group by all columns. |
1268 | |
1269 | For more examples of using these attributes, see |
1270 | L<DBIx::Class::Manual::Cookbook>. |
54540863 |
1271 | |
bfab575a |
1272 | =cut |
076652e8 |
1273 | |
89c0a5a2 |
1274 | 1; |