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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; |
109 | $self->throw_exception("Can't call *_related as class methods") unless ref $self; |
110 | my $rel = shift; |
111 | my $rel_obj = $self->relationship_info($rel); |
112 | $self->throw_exception( "No such relationship ${rel}" ) unless $rel_obj; |
113 | |
114 | return $self->{related_resultsets}{$rel} ||= do { |
115 | my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {}); |
116 | $attrs = { %{$rel_obj->{attrs} || {}}, %$attrs }; |
117 | |
118 | $self->throw_exception( "Invalid query: @_" ) if (@_ > 1 && (@_ % 2 == 1)); |
119 | my $query = ((@_ > 1) ? {@_} : shift); |
120 | |
121 | my $cond = $self->result_source->resolve_condition($rel_obj->{cond}, $rel, $self); |
122 | if (ref $cond eq 'ARRAY') { |
123 | $cond = [ map { my $hash; |
124 | foreach my $key (keys %$_) { |
125 | my $newkey = $key =~ /\./ ? "me.$key" : $key; |
126 | $hash->{$newkey} = $_->{$key}; |
127 | }; $hash } @$cond ]; |
128 | } else { |
129 | foreach my $key (grep { ! /\./ } keys %$cond) { |
130 | $cond->{"me.$key"} = delete $cond->{$key}; |
131 | } |
132 | } |
133 | $query = ($query ? { '-and' => [ $cond, $query ] } : $cond); |
134 | $self->result_source->related_source($rel)->resultset->search($query, $attrs); |
135 | }; |
136 | } |
137 | |
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138 | =head2 search_related |
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139 | |
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140 | $rs->search_related('relname', $cond, $attrs); |
141 | |
142 | Run a search on a related resultset. The search will be restricted to the |
143 | item or items represented by the L<DBIx::Class::ResultSet> it was called |
144 | upon. This method can be called on a ResultSet, a Row or a ResultSource class. |
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145 | |
146 | =cut |
147 | |
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148 | sub search_related { |
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149 | return shift->related_resultset(shift)->search(@_); |
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150 | } |
151 | |
152 | =head2 count_related |
153 | |
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154 | $obj->count_related('relname', $cond, $attrs); |
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155 | |
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156 | Returns the count of all the items in the related resultset, restricted by |
157 | the current item or where conditions. Can be called on a L<DBIx::Classl::Manual::Glossary/"ResultSet"> or a L<DBIx::Class::Manual::Glossary/"Row"> object. |
158 | |
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159 | =cut |
160 | |
161 | sub count_related { |
162 | my $self = shift; |
163 | return $self->search_related(@_)->count; |
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164 | } |
165 | |
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166 | =head2 new_related |
167 | |
168 | my $new_obj = $obj->new_related('relname', \%col_data); |
169 | |
170 | Create a new item of the related foreign class. If called on a |
171 | L<DBIx::Class::Manual::Glossary/"Row"> object, it will magically |
172 | set any primary key values into foreign key columns for you. The newly |
173 | created item will not be saved into your storage until you call C<insert> |
174 | on it. |
175 | |
176 | =cut |
177 | |
178 | sub new_related { |
179 | my ($self, $rel, $values, $attrs) = @_; |
180 | return $self->search_related($rel)->new($values, $attrs); |
181 | } |
182 | |
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183 | =head2 create_related |
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184 | |
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185 | my $new_obj = $obj->create_related('relname', \%col_data); |
186 | |
187 | Creates a new item, similarly to new_related, and also inserts the item's data |
188 | into your storage medium. See the distinction between C<create> and C<new> |
189 | in L<DBIx::Class::ResultSet> for details. |
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190 | |
191 | =cut |
192 | |
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193 | sub create_related { |
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194 | my $self = shift; |
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195 | my $rel = shift; |
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196 | my $obj = $self->search_related($rel)->create(@_); |
197 | delete $self->{related_resultsets}->{$rel}; |
198 | return $obj; |
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199 | } |
200 | |
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201 | =head2 find_related |
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202 | |
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203 | my $found_item = $obj->find_related('relname', @pri_vals | \%pri_vals); |
204 | |
205 | Attempt to find a related object using its primary key or unique constraints. |
206 | See C<find> in L<DBIx::Class::ResultSet> for details. |
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207 | |
208 | =cut |
209 | |
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210 | sub find_related { |
211 | my $self = shift; |
212 | my $rel = shift; |
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213 | return $self->search_related($rel)->find(@_); |
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214 | } |
215 | |
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216 | =head2 find_or_create_related |
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217 | |
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218 | my $new_obj = $obj->find_or_create_related('relname', \%col_data); |
219 | |
220 | Find or create an item of a related class. See C<find_or_create> in |
221 | L<DBIx::Class::ResultSet> for details. |
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222 | |
223 | =cut |
224 | |
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225 | sub find_or_create_related { |
226 | my $self = shift; |
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227 | return $self->find_related(@_) || $self->create_related(@_); |
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228 | } |
229 | |
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230 | =head2 set_from_related |
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231 | |
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232 | $book->set_from_related('author', $author_obj); |
233 | |
234 | Set column values on the current object, using related values from the given |
235 | related object. This is used to associate previously separate objects, for |
236 | example, to set the correct author for a book, find the Author object, then |
237 | call set_from_related on the book. |
238 | |
239 | The columns are only set in the local copy of the object, call C<update> to set |
240 | them in the storage. |
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241 | |
242 | =cut |
243 | |
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244 | sub set_from_related { |
245 | my ($self, $rel, $f_obj) = @_; |
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246 | my $rel_obj = $self->relationship_info($rel); |
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247 | $self->throw_exception( "No such relationship ${rel}" ) unless $rel_obj; |
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248 | my $cond = $rel_obj->{cond}; |
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249 | $self->throw_exception( "set_from_related can only handle a hash condition; the " |
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250 | ."condition for $rel is of type ".(ref $cond ? ref $cond : 'plain scalar')) |
251 | unless ref $cond eq 'HASH'; |
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252 | my $f_class = $self->result_source->schema->class($rel_obj->{class}); |
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253 | $self->throw_exception( "Object $f_obj isn't a ".$f_class ) |
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254 | unless $f_obj->isa($f_class); |
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255 | $self->set_columns( |
256 | $self->result_source->resolve_condition( |
257 | $rel_obj->{cond}, $f_obj, $rel)); |
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258 | return 1; |
259 | } |
260 | |
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261 | =head2 update_from_related |
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262 | |
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263 | $book->update_from_related('author', $author_obj); |
264 | |
265 | As C<set_from_related>, but the changes are immediately updated onto your |
266 | storage. |
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267 | |
268 | =cut |
269 | |
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270 | sub update_from_related { |
271 | my $self = shift; |
272 | $self->set_from_related(@_); |
273 | $self->update; |
274 | } |
275 | |
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276 | =head2 delete_related |
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277 | |
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278 | $obj->delete_related('relname', $cond, $attrs); |
279 | |
280 | Delete any related item subject to the given conditions. |
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281 | |
282 | =cut |
283 | |
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284 | sub delete_related { |
285 | my $self = shift; |
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286 | my $obj = $self->search_related(@_)->delete; |
287 | delete $self->{related_resultsets}->{$_[0]}; |
288 | return $obj; |
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289 | } |
290 | |
291 | 1; |
292 | |
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293 | =head1 AUTHORS |
294 | |
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295 | Matt S. Trout <mst@shadowcatsystems.co.uk> |
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296 | |
297 | =head1 LICENSE |
298 | |
299 | You may distribute this code under the same terms as Perl itself. |
300 | |
301 | =cut |
302 | |