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89c0a5a2 |
1 | package DBIx::Class::ResultSet; |
2 | |
3 | use strict; |
4 | use warnings; |
5 | use overload |
6 | '0+' => 'count', |
7 | fallback => 1; |
3c5b25c5 |
8 | use Data::Page; |
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9 | |
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10 | =head1 NAME |
11 | |
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12 | DBIx::Class::ResultSet - Responsible for fetching and creating resultset. |
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13 | |
df8abd99 |
14 | =head1 SYNOPSIS |
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15 | |
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16 | my $rs = MyApp::DB::Class->search(registered => 1); |
17 | my @rows = MyApp::DB::Class->search(foo => 'bar'); |
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18 | |
19 | =head1 DESCRIPTION |
20 | |
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21 | The resultset is also known as an iterator. It is responsible for handling |
22 | queries that may return an arbitrary number of rows, e.g. via C<search> |
23 | or a C<has_many> relationship. |
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24 | |
25 | =head1 METHODS |
26 | |
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27 | =head2 new($db_class, \%$attrs) |
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28 | |
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29 | The resultset constructor. Takes a table class and an attribute hash |
30 | (see below for more information on attributes). Does not perform |
31 | any queries -- these are executed as needed by the other methods. |
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32 | |
33 | =cut |
34 | |
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35 | sub new { |
7624b19f |
36 | my ($it_class, $db_class, $attrs) = @_; |
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37 | #use Data::Dumper; warn Dumper(@_); |
38 | $it_class = ref $it_class if ref $it_class; |
39 | $attrs = { %{ $attrs || {} } }; |
c7ce65e6 |
40 | my %seen; |
41 | $attrs->{cols} ||= [ map { "me.$_" } $db_class->_select_columns ]; |
42 | $attrs->{from} ||= [ { 'me' => $db_class->_table_name } ]; |
fef5d100 |
43 | if ($attrs->{join}) { |
c7ce65e6 |
44 | foreach my $j (ref $attrs->{join} eq 'ARRAY' |
45 | ? (@{$attrs->{join}}) : ($attrs->{join})) { |
46 | if (ref $j eq 'HASH') { |
47 | $seen{$_} = 1 foreach keys %$j; |
48 | } else { |
49 | $seen{$j} = 1; |
50 | } |
51 | } |
52 | push(@{$attrs->{from}}, $db_class->_resolve_join($attrs->{join}, 'me')); |
53 | } |
54 | foreach my $pre (@{$attrs->{prefetch} || []}) { |
55 | push(@{$attrs->{from}}, $db_class->_resolve_join($pre, 'me')) |
56 | unless $seen{$pre}; |
57 | push(@{$attrs->{cols}}, |
58 | map { "$pre.$_" } |
ddab752c |
59 | $db_class->_relationships->{$pre}->{class}->_select_columns); |
fef5d100 |
60 | } |
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61 | my $new = { |
62 | class => $db_class, |
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63 | cols => $attrs->{cols} || [ $db_class->_select_columns ], |
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64 | cond => $attrs->{where}, |
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65 | from => $attrs->{from} || $db_class->_table_name, |
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66 | count => undef, |
67 | pager => undef, |
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68 | attrs => $attrs }; |
9229f20a |
69 | bless ($new, $it_class); |
70 | $new->pager if ($attrs->{page}); |
71 | return $new; |
89c0a5a2 |
72 | } |
73 | |
df8abd99 |
74 | =head2 cursor |
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75 | |
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76 | Return a storage-driven cursor to the given resultset. |
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77 | |
78 | =cut |
79 | |
73f58123 |
80 | sub cursor { |
81 | my ($self) = @_; |
82 | my ($db_class, $attrs) = @{$self}{qw/class attrs/}; |
3c5b25c5 |
83 | if ($attrs->{page}) { |
84 | $attrs->{rows} = $self->pager->entries_per_page; |
85 | $attrs->{offset} = $self->pager->skipped; |
86 | } |
73f58123 |
87 | return $self->{cursor} |
fef5d100 |
88 | ||= $db_class->storage->select($self->{from}, $self->{cols}, |
73f58123 |
89 | $attrs->{where},$attrs); |
90 | } |
91 | |
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92 | =head2 slice($first, $last) |
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93 | |
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94 | Returns a subset of elements from the resultset. |
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95 | |
96 | =cut |
97 | |
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98 | sub slice { |
99 | my ($self, $min, $max) = @_; |
100 | my $attrs = { %{ $self->{attrs} || {} } }; |
101 | $self->{class}->throw("Can't slice without where") unless $attrs->{where}; |
102 | $attrs->{offset} = $min; |
103 | $attrs->{rows} = ($max ? ($max - $min + 1) : 1); |
7624b19f |
104 | my $slice = $self->new($self->{class}, $attrs); |
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105 | return (wantarray ? $slice->all : $slice); |
106 | } |
107 | |
df8abd99 |
108 | =head2 next |
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109 | |
df8abd99 |
110 | Returns the next element in the resultset (undef is there is none). |
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111 | |
112 | =cut |
113 | |
89c0a5a2 |
114 | sub next { |
115 | my ($self) = @_; |
73f58123 |
116 | my @row = $self->cursor->next; |
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117 | return unless (@row); |
c7ce65e6 |
118 | return $self->_construct_object(@row); |
119 | } |
120 | |
121 | sub _construct_object { |
122 | my ($self, @row) = @_; |
90f3f5ff |
123 | my @cols = @{ $self->{attrs}{cols} }; |
124 | s/^me\.// for @cols; |
3cbddeb1 |
125 | @cols = grep { /\(/ or ! /\./ } @cols; |
33ce49d6 |
126 | my $new; |
c7ce65e6 |
127 | unless ($self->{attrs}{prefetch}) { |
33ce49d6 |
128 | $new = $self->{class}->_row_to_object(\@cols, \@row); |
c7ce65e6 |
129 | } else { |
130 | my @main = splice(@row, 0, scalar @cols); |
33ce49d6 |
131 | $new = $self->{class}->_row_to_object(\@cols, \@main); |
c7ce65e6 |
132 | PRE: foreach my $pre (@{$self->{attrs}{prefetch}}) { |
133 | my $rel_obj = $self->{class}->_relationships->{$pre}; |
dd417d06 |
134 | my $pre_class = $self->{class}->resolve_class($rel_obj->{class}); |
135 | my @pre_cols = $pre_class->_select_columns; |
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136 | my @vals = splice(@row, 0, scalar @pre_cols); |
dd417d06 |
137 | my $fetched = $pre_class->_row_to_object(\@pre_cols, \@vals); |
c7ce65e6 |
138 | $self->{class}->throw("No accessor for prefetched $pre") |
139 | unless defined $rel_obj->{attrs}{accessor}; |
140 | if ($rel_obj->{attrs}{accessor} eq 'single') { |
141 | foreach my $pri ($rel_obj->{class}->primary_columns) { |
7cd300ea |
142 | unless (defined $fetched->get_column($pri)) { |
143 | undef $fetched; |
144 | last; |
145 | } |
c7ce65e6 |
146 | } |
147 | $new->{_relationship_data}{$pre} = $fetched; |
148 | } elsif ($rel_obj->{attrs}{accessor} eq 'filter') { |
149 | $new->{_inflated_column}{$pre} = $fetched; |
150 | } else { |
3125eb1f |
151 | $self->{class}->throw("Don't know how to store prefetched $pre"); |
c7ce65e6 |
152 | } |
153 | } |
c7ce65e6 |
154 | } |
33ce49d6 |
155 | $new = $self->{attrs}{record_filter}->($new) |
156 | if exists $self->{attrs}{record_filter}; |
157 | return $new; |
89c0a5a2 |
158 | } |
159 | |
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160 | =head2 count |
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161 | |
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162 | Performs an SQL C<COUNT> with the same query as the resultset was built |
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163 | with to find the number of elements. |
164 | |
165 | =cut |
166 | |
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167 | sub count { |
168 | my ($self) = @_; |
7624b19f |
169 | my $db_class = $self->{class}; |
59f8e584 |
170 | my $attrs = { %{ $self->{attrs} } }; |
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171 | unless ($self->{count}) { |
172 | # offset and order by are not needed to count |
173 | delete $attrs->{$_} for qw/offset order_by/; |
174 | |
175 | my @cols = 'COUNT(*)'; |
fef5d100 |
176 | $self->{count} = $db_class->storage->select_single($self->{from}, \@cols, |
3c5b25c5 |
177 | $self->{cond}, $attrs); |
178 | } |
179 | return 0 unless $self->{count}; |
9229f20a |
180 | return $self->{pager}->entries_on_this_page if ($self->{pager}); |
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181 | return ( $attrs->{rows} && $attrs->{rows} < $self->{count} ) |
59f8e584 |
182 | ? $attrs->{rows} |
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183 | : $self->{count}; |
89c0a5a2 |
184 | } |
185 | |
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186 | =head2 all |
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187 | |
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188 | Returns all elements in the resultset. Called implictly if the resultset |
189 | is returned in list context. |
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190 | |
191 | =cut |
192 | |
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193 | sub all { |
194 | my ($self) = @_; |
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195 | return map { $self->_construct_object(@$_); } |
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196 | $self->cursor->all; |
89c0a5a2 |
197 | } |
198 | |
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199 | =head2 reset |
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200 | |
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201 | Resets the resultset's cursor, so you can iterate through the elements again. |
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202 | |
203 | =cut |
204 | |
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205 | sub reset { |
206 | my ($self) = @_; |
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207 | $self->cursor->reset; |
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208 | return $self; |
209 | } |
210 | |
df8abd99 |
211 | =head2 first |
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212 | |
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213 | Resets the resultset and returns the first element. |
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214 | |
215 | =cut |
216 | |
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217 | sub first { |
218 | return $_[0]->reset->next; |
219 | } |
220 | |
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221 | =head2 delete |
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222 | |
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223 | Deletes all elements in the resultset. |
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224 | |
225 | =cut |
226 | |
28927b50 |
227 | sub delete { |
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228 | my ($self) = @_; |
229 | $_->delete for $self->all; |
230 | return 1; |
231 | } |
232 | |
28927b50 |
233 | *delete_all = \&delete; # Yeah, yeah, yeah ... |
234 | |
df8abd99 |
235 | =head2 pager |
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236 | |
237 | Returns a L<Data::Page> object for the current resultset. Only makes |
238 | sense for queries with page turned on. |
239 | |
240 | =cut |
241 | |
3c5b25c5 |
242 | sub pager { |
243 | my ($self) = @_; |
244 | my $attrs = $self->{attrs}; |
245 | delete $attrs->{offset}; |
246 | my $rows_per_page = delete $attrs->{rows} || 10; |
247 | $self->{pager} ||= Data::Page->new( |
248 | $self->count, $rows_per_page, $attrs->{page} || 1); |
249 | $attrs->{rows} = $rows_per_page; |
250 | return $self->{pager}; |
251 | } |
252 | |
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253 | =head2 page($page_num) |
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254 | |
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255 | Returns a new resultset for the specified page. |
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256 | |
257 | =cut |
258 | |
3c5b25c5 |
259 | sub page { |
260 | my ($self, $page) = @_; |
261 | my $attrs = $self->{attrs}; |
262 | $attrs->{page} = $page; |
263 | return $self->new($self->{class}, $attrs); |
264 | } |
265 | |
076652e8 |
266 | =head1 Attributes |
267 | |
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268 | The resultset takes various attributes that modify its behavior. |
269 | Here's an overview of them: |
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270 | |
df8abd99 |
271 | =head2 order_by |
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272 | |
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273 | Which column(s) to order the results by. This is currently passed |
274 | through directly to SQL, so you can give e.g. C<foo DESC> for a |
275 | descending order. |
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276 | |
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277 | =head2 cols |
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278 | |
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279 | Which columns should be retrieved. |
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280 | |
df8abd99 |
281 | =head2 join |
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282 | |
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283 | Contains a list of relationships that should be joined for this query. Can also |
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284 | contain a hash reference to refer to that relation's relations. So, if one column |
285 | in your class C<belongs_to> foo and another C<belongs_to> bar, you can do |
286 | C<< join => [qw/ foo bar /] >> to join both (and e.g. use them for C<order_by>). |
287 | If a foo contains many margles and you want to join those too, you can do |
288 | C<< join => { foo => 'margle' } >>. If you want to fetch the columns from the |
289 | related table as well, see C<prefetch> below. |
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290 | |
87980de7 |
291 | =head2 prefetch |
292 | |
293 | Contains a list of relationships that should be fetched along with the main |
294 | query (when they are accessed afterwards they will have already been |
295 | "prefetched"). This is useful for when you know you will need the related |
296 | object(s), because it saves a query. Currently limited to prefetching |
297 | one relationship deep, so unlike C<join>, prefetch must be an arrayref. |
298 | |
df8abd99 |
299 | =head2 from |
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300 | |
df8abd99 |
301 | This attribute can contain a arrayref of elements. Each element can be another |
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302 | arrayref, to nest joins, or it can be a hash which represents the two sides |
303 | of the join. |
304 | |
df8abd99 |
305 | NOTE: Use this on your own risk. This allows you to shoot your foot off! |
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306 | |
df8abd99 |
307 | =head2 page |
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308 | |
df8abd99 |
309 | For a paged resultset, specifies which page to retrieve. Leave unset |
310 | for an unpaged resultset. |
076652e8 |
311 | |
df8abd99 |
312 | =head2 rows |
076652e8 |
313 | |
df8abd99 |
314 | For a paged resultset, how many rows per page |
076652e8 |
315 | |
df8abd99 |
316 | =cut |
076652e8 |
317 | |
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318 | 1; |