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1 | package DBIx::Class::Relationship::Base; |
2 | |
3 | use strict; |
4 | use warnings; |
5 | |
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6 | use base qw/DBIx::Class/; |
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7 | |
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8 | =head1 NAME |
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9 | |
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10 | DBIx::Class::Relationship::Base - Inter-table relationships |
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11 | |
12 | =head1 SYNOPSIS |
13 | |
14 | =head1 DESCRIPTION |
15 | |
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16 | This class provides methods to describe the relationships between the |
17 | tables in your database model. These are the "bare bones" relationships |
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18 | methods, for predefined ones, look in L<DBIx::Class::Relationship>. |
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19 | |
20 | =head1 METHODS |
21 | |
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22 | =head2 add_relationship |
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23 | |
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24 | =over 4 |
25 | |
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26 | =item Arguments: 'relname', 'Foreign::Class', $cond, $attrs |
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27 | |
28 | =back |
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29 | |
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30 | __PACKAGE__->add_relationship('relname', 'Foreign::Class', $cond, $attrs); |
31 | |
32 | The condition needs to be an SQL::Abstract-style representation of the |
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33 | join between the tables. When resolving the condition for use in a JOIN, |
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34 | keys using the pseudo-table I<foreign> are resolved to mean "the Table on the |
35 | other side of the relationship", and values using the pseudo-table I<self> |
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36 | are resolved to mean "the Table this class is representing". Other |
37 | restrictions, such as by value, sub-select and other tables, may also be |
38 | used. Please check your database for JOIN parameter support. |
39 | |
40 | For example, if you're creating a rel from Author to Book, where the Book |
41 | table has a column author_id containing the ID of the Author row: |
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42 | |
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43 | { 'foreign.author_id' => 'self.id' } |
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44 | |
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45 | will result in the JOIN clause |
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46 | |
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47 | author me JOIN book book ON bar.author_id = me.id |
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48 | |
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49 | You can specify as many foreign => self mappings as necessary. Each key/value |
50 | pair provided in a hashref will be used as ANDed conditions, to add an ORed |
51 | condition, use an arrayref of hashrefs. See the L<SQL::Abstract> documentation |
52 | for more details. |
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53 | |
54 | Valid attributes are as follows: |
55 | |
56 | =over 4 |
57 | |
58 | =item join_type |
59 | |
60 | Explicitly specifies the type of join to use in the relationship. Any SQL |
61 | join type is valid, e.g. C<LEFT> or C<RIGHT>. It will be placed in the SQL |
62 | command immediately before C<JOIN>. |
63 | |
64 | =item proxy |
65 | |
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66 | An arrayref containing a list of accessors in the foreign class to create in |
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67 | the main class. If, for example, you do the following: |
68 | |
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69 | MyDB::Schema::CD->might_have(liner_notes => 'MyDB::Schema::LinerNotes', |
70 | undef, { |
71 | proxy => [ qw/notes/ ], |
72 | }); |
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73 | |
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74 | Then, assuming MyDB::Schema::LinerNotes has an accessor named notes, you can do: |
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75 | |
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76 | my $cd = MyDB::Schema::CD->find(1); |
77 | $cd->notes('Notes go here'); # set notes -- LinerNotes object is |
78 | # created if it doesn't exist |
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79 | |
80 | =item accessor |
81 | |
82 | Specifies the type of accessor that should be created for the relationship. |
83 | Valid values are C<single> (for when there is only a single related object), |
84 | C<multi> (when there can be many), and C<filter> (for when there is a single |
85 | related object, but you also want the relationship accessor to double as |
86 | a column accessor). For C<multi> accessors, an add_to_* method is also |
87 | created, which calls C<create_related> for the relationship. |
88 | |
89 | =back |
90 | |
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91 | =head2 register_relationship |
92 | |
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93 | =over 4 |
94 | |
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95 | =item Arguments: $relname, $rel_info |
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96 | |
97 | =back |
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98 | |
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99 | Registers a relationship on the class. This is called internally by |
100 | L<DBIx::Class::ResultSourceProxy> to set up Accessors and Proxies. |
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101 | |
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102 | =cut |
103 | |
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104 | sub register_relationship { } |
105 | |
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106 | =head2 related_resultset |
107 | |
108 | =over 4 |
109 | |
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110 | =item Arguments: $relationship_name |
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111 | |
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112 | =item Return Value: $related_resultset |
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113 | |
114 | =back |
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115 | |
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116 | $rs = $cd->related_resultset('artist'); |
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117 | |
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118 | Returns a L<DBIx::Class::ResultSet> for the relationship named |
119 | $relationship_name. |
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120 | |
121 | =cut |
122 | |
123 | sub related_resultset { |
124 | my $self = shift; |
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125 | $self->throw_exception("Can't call *_related as class methods") |
126 | unless ref $self; |
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127 | my $rel = shift; |
128 | my $rel_obj = $self->relationship_info($rel); |
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129 | $self->throw_exception( "No such relationship ${rel}" ) |
130 | unless $rel_obj; |
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131 | |
132 | return $self->{related_resultsets}{$rel} ||= do { |
133 | my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {}); |
134 | $attrs = { %{$rel_obj->{attrs} || {}}, %$attrs }; |
135 | |
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136 | $self->throw_exception( "Invalid query: @_" ) |
137 | if (@_ > 1 && (@_ % 2 == 1)); |
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138 | my $query = ((@_ > 1) ? {@_} : shift); |
139 | |
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140 | my $cond = $self->result_source->resolve_condition( |
141 | $rel_obj->{cond}, $rel, $self |
142 | ); |
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143 | if (ref $cond eq 'ARRAY') { |
144 | $cond = [ map { my $hash; |
145 | foreach my $key (keys %$_) { |
146 | my $newkey = $key =~ /\./ ? "me.$key" : $key; |
147 | $hash->{$newkey} = $_->{$key}; |
148 | }; $hash } @$cond ]; |
149 | } else { |
150 | foreach my $key (grep { ! /\./ } keys %$cond) { |
151 | $cond->{"me.$key"} = delete $cond->{$key}; |
152 | } |
153 | } |
154 | $query = ($query ? { '-and' => [ $cond, $query ] } : $cond); |
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155 | $self->result_source->related_source($rel)->resultset->search( |
156 | $query, $attrs |
157 | ); |
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158 | }; |
159 | } |
160 | |
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161 | =head2 search_related |
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162 | |
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163 | $rs->search_related('relname', $cond, $attrs); |
164 | |
165 | Run a search on a related resultset. The search will be restricted to the |
166 | item or items represented by the L<DBIx::Class::ResultSet> it was called |
167 | upon. This method can be called on a ResultSet, a Row or a ResultSource class. |
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168 | |
169 | =cut |
170 | |
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171 | sub search_related { |
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172 | return shift->related_resultset(shift)->search(@_); |
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173 | } |
174 | |
175 | =head2 count_related |
176 | |
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177 | $obj->count_related('relname', $cond, $attrs); |
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178 | |
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179 | Returns the count of all the items in the related resultset, restricted by the |
180 | current item or where conditions. Can be called on a |
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181 | L<DBIx::Class::Manual::Glossary/"ResultSet"> or a |
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182 | L<DBIx::Class::Manual::Glossary/"Row"> object. |
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183 | |
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184 | =cut |
185 | |
186 | sub count_related { |
187 | my $self = shift; |
188 | return $self->search_related(@_)->count; |
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189 | } |
190 | |
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191 | =head2 new_related |
192 | |
193 | my $new_obj = $obj->new_related('relname', \%col_data); |
194 | |
195 | Create a new item of the related foreign class. If called on a |
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196 | L<DBIx::Class::Manual::Glossary/"Row"> object, it will magically set any |
197 | primary key values into foreign key columns for you. The newly created item |
198 | will not be saved into your storage until you call L<DBIx::Class::Row/insert> |
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199 | on it. |
200 | |
201 | =cut |
202 | |
203 | sub new_related { |
204 | my ($self, $rel, $values, $attrs) = @_; |
205 | return $self->search_related($rel)->new($values, $attrs); |
206 | } |
207 | |
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208 | =head2 create_related |
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209 | |
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210 | my $new_obj = $obj->create_related('relname', \%col_data); |
211 | |
212 | Creates a new item, similarly to new_related, and also inserts the item's data |
213 | into your storage medium. See the distinction between C<create> and C<new> |
214 | in L<DBIx::Class::ResultSet> for details. |
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215 | |
216 | =cut |
217 | |
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218 | sub create_related { |
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219 | my $self = shift; |
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220 | my $rel = shift; |
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221 | my $obj = $self->search_related($rel)->create(@_); |
222 | delete $self->{related_resultsets}->{$rel}; |
223 | return $obj; |
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224 | } |
225 | |
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226 | =head2 find_related |
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227 | |
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228 | my $found_item = $obj->find_related('relname', @pri_vals | \%pri_vals); |
229 | |
230 | Attempt to find a related object using its primary key or unique constraints. |
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231 | See L<DBIx::Class::ResultSet/find> for details. |
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232 | |
233 | =cut |
234 | |
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235 | sub find_related { |
236 | my $self = shift; |
237 | my $rel = shift; |
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238 | return $self->search_related($rel)->find(@_); |
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239 | } |
240 | |
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241 | =head2 find_or_new_related |
242 | |
243 | my $new_obj = $obj->find_or_new_related('relname', \%col_data); |
244 | |
245 | Find an item of a related class. If none exists, instantiate a new item of the |
246 | related class. The object will not be saved into your storage until you call |
247 | L<DBIx::Class::Row/insert> on it. |
248 | |
249 | =cut |
250 | |
251 | sub find_or_new_related { |
252 | my $self = shift; |
253 | return $self->find_related(@_) || $self->new_related(@_); |
254 | } |
255 | |
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256 | =head2 find_or_create_related |
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257 | |
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258 | my $new_obj = $obj->find_or_create_related('relname', \%col_data); |
259 | |
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260 | Find or create an item of a related class. See |
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261 | L<DBIx::Class::ResultSet/find_or_create> for details. |
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262 | |
263 | =cut |
264 | |
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265 | sub find_or_create_related { |
266 | my $self = shift; |
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267 | return $self->find_related(@_) || $self->create_related(@_); |
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268 | } |
269 | |
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270 | =head2 update_or_create_related |
271 | |
272 | my $updated_item = $obj->update_or_create_related('relname', \%col_data, \%attrs?); |
273 | |
274 | Update or create an item of a related class. See |
275 | L<DBIx::Class::ResultSet/"update_or_create"> for details. |
276 | |
277 | =cut |
278 | |
279 | sub update_or_create_related { |
280 | my $self = shift; |
281 | my $rel = shift; |
282 | return $self->related_resultset($rel)->update_or_create(@_); |
283 | } |
284 | |
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285 | =head2 set_from_related |
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286 | |
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287 | $book->set_from_related('author', $author_obj); |
288 | |
289 | Set column values on the current object, using related values from the given |
290 | related object. This is used to associate previously separate objects, for |
291 | example, to set the correct author for a book, find the Author object, then |
292 | call set_from_related on the book. |
293 | |
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294 | The columns are only set in the local copy of the object, call L</update> to |
295 | set them in the storage. |
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296 | |
297 | =cut |
298 | |
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299 | sub set_from_related { |
300 | my ($self, $rel, $f_obj) = @_; |
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301 | my $rel_obj = $self->relationship_info($rel); |
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302 | $self->throw_exception( "No such relationship ${rel}" ) unless $rel_obj; |
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303 | my $cond = $rel_obj->{cond}; |
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304 | $self->throw_exception( |
305 | "set_from_related can only handle a hash condition; the ". |
306 | "condition for $rel is of type ". |
307 | (ref $cond ? ref $cond : 'plain scalar') |
308 | ) unless ref $cond eq 'HASH'; |
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309 | my $f_class = $self->result_source->schema->class($rel_obj->{class}); |
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310 | $self->throw_exception( "Object $f_obj isn't a ".$f_class ) |
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311 | unless $f_obj->isa($f_class); |
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312 | $self->set_columns( |
313 | $self->result_source->resolve_condition( |
314 | $rel_obj->{cond}, $f_obj, $rel)); |
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315 | return 1; |
316 | } |
317 | |
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318 | =head2 update_from_related |
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319 | |
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320 | $book->update_from_related('author', $author_obj); |
321 | |
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322 | The same as L</"set_from_related">, but the changes are immediately updated |
323 | in storage. |
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324 | |
325 | =cut |
326 | |
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327 | sub update_from_related { |
328 | my $self = shift; |
329 | $self->set_from_related(@_); |
330 | $self->update; |
331 | } |
332 | |
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333 | =head2 delete_related |
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334 | |
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335 | $obj->delete_related('relname', $cond, $attrs); |
336 | |
337 | Delete any related item subject to the given conditions. |
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338 | |
339 | =cut |
340 | |
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341 | sub delete_related { |
342 | my $self = shift; |
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343 | my $obj = $self->search_related(@_)->delete; |
344 | delete $self->{related_resultsets}->{$_[0]}; |
345 | return $obj; |
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346 | } |
347 | |
348 | 1; |
349 | |
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350 | =head1 AUTHORS |
351 | |
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352 | Matt S. Trout <mst@shadowcatsystems.co.uk> |
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353 | |
354 | =head1 LICENSE |
355 | |
356 | You may distribute this code under the same terms as Perl itself. |
357 | |
358 | =cut |
359 | |