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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 | |
8 | __PACKAGE__->mk_classdata('_relationships', { } ); |
9 | |
10 | =head1 NAME |
11 | |
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12 | DBIx::Class::Relationship::Base - Inter-table relationships |
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13 | |
14 | =head1 SYNOPSIS |
15 | |
16 | =head1 DESCRIPTION |
17 | |
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18 | This class provides methods to describe the relationships between the |
19 | tables in your database model. These are the "bare bones" relationships |
20 | methods, for predefined ones, look in L<DBIx::Class::Relationship>. |
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21 | |
22 | =head1 METHODS |
23 | |
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24 | =head2 add_relationship |
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25 | |
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26 | =head3 Arguments: ('relname', 'Foreign::Class', $cond, $attrs) |
27 | |
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28 | __PACKAGE__->add_relationship('relname', 'Foreign::Class', $cond, $attrs); |
29 | |
30 | The condition needs to be an SQL::Abstract-style representation of the |
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31 | join between the tables. When resolving the condition for use in a JOIN, |
32 | keys using the psuedo-table I<foreign> are resolved to mean "the Table on the |
33 | other side of the relationship", and values using the psuedo-table I<self> |
34 | are resolved to mean "the Table this class is representing". Other |
35 | restrictions, such as by value, sub-select and other tables, may also be |
36 | used. Please check your database for JOIN parameter support. |
37 | |
38 | For example, if you're creating a rel from Author to Book, where the Book |
39 | table has a column author_id containing the ID of the Author row: |
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40 | |
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41 | { 'foreign.author_id' => 'self.id' } |
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42 | |
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43 | will result in the JOIN clause |
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44 | |
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45 | author me JOIN book book ON bar.author_id = me.id |
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46 | |
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47 | You can specify as many foreign => self mappings as necessary. Each key/value |
48 | pair provided in a hashref will be used as ANDed conditions, to add an ORed |
49 | condition, use an arrayref of hashrefs. See the L<SQL::Abstract> documentation |
50 | for more details. |
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51 | |
52 | Valid attributes are as follows: |
53 | |
54 | =over 4 |
55 | |
56 | =item join_type |
57 | |
58 | Explicitly specifies the type of join to use in the relationship. Any SQL |
59 | join type is valid, e.g. C<LEFT> or C<RIGHT>. It will be placed in the SQL |
60 | command immediately before C<JOIN>. |
61 | |
62 | =item proxy |
63 | |
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64 | An arrayref containing a list of accessors in the foreign class to create in |
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65 | the main class. If, for example, you do the following: |
66 | |
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67 | MyDB::Schema::CD->might_have(liner_notes => 'MyDB::Schema::LinerNotes', undef, { |
68 | proxy => [ qw/notes/ ], |
69 | }); |
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70 | |
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71 | Then, assuming MyDB::Schema::LinerNotes has an accessor named notes, you can do: |
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72 | |
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73 | my $cd = MyDB::Schema::CD->find(1); |
74 | $cd->notes('Notes go here'); # set notes -- LinerNotes object is |
75 | # created if it doesn't exist |
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76 | |
77 | =item accessor |
78 | |
79 | Specifies the type of accessor that should be created for the relationship. |
80 | Valid values are C<single> (for when there is only a single related object), |
81 | C<multi> (when there can be many), and C<filter> (for when there is a single |
82 | related object, but you also want the relationship accessor to double as |
83 | a column accessor). For C<multi> accessors, an add_to_* method is also |
84 | created, which calls C<create_related> for the relationship. |
85 | |
86 | =back |
87 | |
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88 | =head2 register_relationship |
89 | |
90 | =head3 Arguments: ($relname, $rel_info) |
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91 | |
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92 | Registers a relationship on the class. This is called internally by |
93 | L<DBIx::Class::ResultSourceProxy> to set up Accessors and Proxies. |
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94 | |
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95 | =cut |
96 | |
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97 | sub register_relationship { } |
98 | |
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99 | =head2 related_resultset($name) |
100 | |
101 | $rs = $obj->related_resultset('related_table'); |
102 | |
103 | Returns a L<DBIx::Class::ResultSet> for the relationship named $name. |
104 | |
105 | =cut |
106 | |
107 | sub related_resultset { |
108 | my $self = shift; |
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109 | $self->throw_exception("Can't call *_related as class methods") |
110 | unless ref $self; |
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111 | my $rel = shift; |
112 | my $rel_obj = $self->relationship_info($rel); |
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113 | $self->throw_exception( "No such relationship ${rel}" ) |
114 | unless $rel_obj; |
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115 | |
116 | return $self->{related_resultsets}{$rel} ||= do { |
117 | my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {}); |
118 | $attrs = { %{$rel_obj->{attrs} || {}}, %$attrs }; |
119 | |
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120 | $self->throw_exception( "Invalid query: @_" ) |
121 | if (@_ > 1 && (@_ % 2 == 1)); |
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122 | my $query = ((@_ > 1) ? {@_} : shift); |
123 | |
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124 | my $cond = $self->result_source->resolve_condition( |
125 | $rel_obj->{cond}, $rel, $self |
126 | ); |
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127 | if (ref $cond eq 'ARRAY') { |
128 | $cond = [ map { my $hash; |
129 | foreach my $key (keys %$_) { |
130 | my $newkey = $key =~ /\./ ? "me.$key" : $key; |
131 | $hash->{$newkey} = $_->{$key}; |
132 | }; $hash } @$cond ]; |
133 | } else { |
134 | foreach my $key (grep { ! /\./ } keys %$cond) { |
135 | $cond->{"me.$key"} = delete $cond->{$key}; |
136 | } |
137 | } |
138 | $query = ($query ? { '-and' => [ $cond, $query ] } : $cond); |
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139 | $self->result_source->related_source($rel)->resultset->search( |
140 | $query, $attrs |
141 | ); |
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142 | }; |
143 | } |
144 | |
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145 | =head2 search_related |
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146 | |
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147 | $rs->search_related('relname', $cond, $attrs); |
148 | |
149 | Run a search on a related resultset. The search will be restricted to the |
150 | item or items represented by the L<DBIx::Class::ResultSet> it was called |
151 | upon. This method can be called on a ResultSet, a Row or a ResultSource class. |
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152 | |
153 | =cut |
154 | |
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155 | sub search_related { |
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156 | return shift->related_resultset(shift)->search(@_); |
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157 | } |
158 | |
159 | =head2 count_related |
160 | |
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161 | $obj->count_related('relname', $cond, $attrs); |
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162 | |
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163 | Returns the count of all the items in the related resultset, restricted by the |
164 | current item or where conditions. Can be called on a |
165 | L<DBIx::Classl::Manual::Glossary/"ResultSet"> or a |
166 | L<DBIx::Class::Manual::Glossary/"Row"> object. |
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167 | |
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168 | =cut |
169 | |
170 | sub count_related { |
171 | my $self = shift; |
172 | return $self->search_related(@_)->count; |
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173 | } |
174 | |
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175 | =head2 new_related |
176 | |
177 | my $new_obj = $obj->new_related('relname', \%col_data); |
178 | |
179 | Create a new item of the related foreign class. If called on a |
180 | L<DBIx::Class::Manual::Glossary/"Row"> object, it will magically |
181 | set any primary key values into foreign key columns for you. The newly |
182 | created item will not be saved into your storage until you call C<insert> |
183 | on it. |
184 | |
185 | =cut |
186 | |
187 | sub new_related { |
188 | my ($self, $rel, $values, $attrs) = @_; |
189 | return $self->search_related($rel)->new($values, $attrs); |
190 | } |
191 | |
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192 | =head2 create_related |
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193 | |
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194 | my $new_obj = $obj->create_related('relname', \%col_data); |
195 | |
196 | Creates a new item, similarly to new_related, and also inserts the item's data |
197 | into your storage medium. See the distinction between C<create> and C<new> |
198 | in L<DBIx::Class::ResultSet> for details. |
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199 | |
200 | =cut |
201 | |
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202 | sub create_related { |
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203 | my $self = shift; |
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204 | my $rel = shift; |
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205 | my $obj = $self->search_related($rel)->create(@_); |
206 | delete $self->{related_resultsets}->{$rel}; |
207 | return $obj; |
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208 | } |
209 | |
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210 | =head2 find_related |
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211 | |
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212 | my $found_item = $obj->find_related('relname', @pri_vals | \%pri_vals); |
213 | |
214 | Attempt to find a related object using its primary key or unique constraints. |
215 | See C<find> in L<DBIx::Class::ResultSet> for details. |
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216 | |
217 | =cut |
218 | |
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219 | sub find_related { |
220 | my $self = shift; |
221 | my $rel = shift; |
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222 | return $self->search_related($rel)->find(@_); |
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223 | } |
224 | |
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225 | =head2 find_or_create_related |
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226 | |
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227 | my $new_obj = $obj->find_or_create_related('relname', \%col_data); |
228 | |
229 | Find or create an item of a related class. See C<find_or_create> in |
230 | L<DBIx::Class::ResultSet> for details. |
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231 | |
232 | =cut |
233 | |
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234 | sub find_or_create_related { |
235 | my $self = shift; |
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236 | return $self->find_related(@_) || $self->create_related(@_); |
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237 | } |
238 | |
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239 | =head2 set_from_related |
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240 | |
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241 | $book->set_from_related('author', $author_obj); |
242 | |
243 | Set column values on the current object, using related values from the given |
244 | related object. This is used to associate previously separate objects, for |
245 | example, to set the correct author for a book, find the Author object, then |
246 | call set_from_related on the book. |
247 | |
248 | The columns are only set in the local copy of the object, call C<update> to set |
249 | them in the storage. |
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250 | |
251 | =cut |
252 | |
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253 | sub set_from_related { |
254 | my ($self, $rel, $f_obj) = @_; |
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255 | my $rel_obj = $self->relationship_info($rel); |
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256 | $self->throw_exception( "No such relationship ${rel}" ) unless $rel_obj; |
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257 | my $cond = $rel_obj->{cond}; |
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258 | $self->throw_exception( |
259 | "set_from_related can only handle a hash condition; the ". |
260 | "condition for $rel is of type ". |
261 | (ref $cond ? ref $cond : 'plain scalar') |
262 | ) unless ref $cond eq 'HASH'; |
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263 | my $f_class = $self->result_source->schema->class($rel_obj->{class}); |
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264 | $self->throw_exception( "Object $f_obj isn't a ".$f_class ) |
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265 | unless $f_obj->isa($f_class); |
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266 | $self->set_columns( |
267 | $self->result_source->resolve_condition( |
268 | $rel_obj->{cond}, $f_obj, $rel)); |
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269 | return 1; |
270 | } |
271 | |
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272 | =head2 update_from_related |
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273 | |
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274 | $book->update_from_related('author', $author_obj); |
275 | |
276 | As C<set_from_related>, but the changes are immediately updated onto your |
277 | storage. |
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278 | |
279 | =cut |
280 | |
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281 | sub update_from_related { |
282 | my $self = shift; |
283 | $self->set_from_related(@_); |
284 | $self->update; |
285 | } |
286 | |
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287 | =head2 delete_related |
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288 | |
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289 | $obj->delete_related('relname', $cond, $attrs); |
290 | |
291 | Delete any related item subject to the given conditions. |
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292 | |
293 | =cut |
294 | |
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295 | sub delete_related { |
296 | my $self = shift; |
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297 | my $obj = $self->search_related(@_)->delete; |
298 | delete $self->{related_resultsets}->{$_[0]}; |
299 | return $obj; |
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300 | } |
301 | |
302 | 1; |
303 | |
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304 | =head1 AUTHORS |
305 | |
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306 | Matt S. Trout <mst@shadowcatsystems.co.uk> |
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307 | |
308 | =head1 LICENSE |
309 | |
310 | You may distribute this code under the same terms as Perl itself. |
311 | |
312 | =cut |
313 | |