Commit | Line | Data |
876f6525 |
1 | package DBIx::Class::ResultSource::MultipleTableInheritance; |
2 | |
3 | use strict; |
4 | use warnings; |
5 | use parent qw(DBIx::Class::ResultSource::View); |
876f6525 |
6 | use Method::Signatures::Simple; |
7 | use Carp::Clan qw/^DBIx::Class/; |
ca79850d |
8 | use aliased 'DBIx::Class::ResultSource::Table'; |
7abe3af2 |
9 | use aliased 'DBIx::Class::ResultClass::HashRefInflator'; |
05fd2477 |
10 | use String::TT qw(strip tt); |
92ebfc06 |
11 | use Scalar::Util qw(blessed); |
ca79850d |
12 | use namespace::autoclean; |
c8e085ba |
13 | use Devel::Dwarn; |
70d56286 |
14 | |
146ec120 |
15 | our $VERSION = 0.01; |
70d56286 |
16 | |
803ffff2 |
17 | __PACKAGE__->mk_group_accessors(simple => qw(parent_source additional_parents)); |
876f6525 |
18 | |
e7189506 |
19 | # how this works: |
20 | # |
21 | # On construction, we hook $self->result_class->result_source_instance |
22 | # if present to get the superclass' source object |
23 | # |
24 | # When attached to a schema, we need to add sources to that schema with |
25 | # appropriate relationships for the foreign keys so the concrete tables |
26 | # get generated |
27 | # |
28 | # We also generate our own view definition using this class' concrete table |
29 | # and the view for the superclass, and stored procedures for the insert, |
30 | # update and delete operations on this view. |
31 | # |
32 | # deploying the postgres rules through SQLT may be a pain though. |
33 | |
876f6525 |
34 | method new ($class: @args) { |
35 | my $new = $class->next::method(@args); |
36 | my $rc = $new->result_class; |
37 | if (my $meth = $rc->can('result_source_instance')) { |
7abe3af2 |
38 | my $source = $rc->$meth; |
39 | if ($source->result_class ne $new->result_class |
40 | && $new->result_class->isa($source->result_class)) { |
41 | $new->parent_source($source); |
42 | } |
876f6525 |
43 | } |
44 | return $new; |
45 | } |
46 | |
4e4f71e3 |
47 | method add_additional_parents (@classes) { |
48 | foreach my $class (@classes) { |
49 | Class::C3::Componentised->ensure_class_loaded($class); |
50 | $self->add_additional_parent( |
51 | $class->result_source_instance |
52 | ); |
53 | } |
54 | } |
55 | |
803ffff2 |
56 | method add_additional_parent ($source) { |
57 | my ($our_pk, $their_pk) = map { |
58 | join('|',sort $_->primary_columns) |
59 | } ($self, $source); |
60 | |
61 | confess "Can't attach additional parent ${\$source->name} - it has different PKs ($their_pk versus our $our_pk)" |
62 | unless $their_pk eq $our_pk; |
63 | $self->additional_parents([ |
64 | @{$self->additional_parents||[]}, $source |
65 | ]); |
66 | $self->add_columns( |
67 | map { |
68 | $_ => # put the extra key first to default it |
69 | { originally_defined_in => $source->name, %{$source->column_info($_)}, }, |
70 | } grep !$self->has_column($_), $source->columns |
71 | ); |
72 | foreach my $rel ($source->relationships) { |
73 | my $rel_info = $source->relationship_info($rel); |
74 | $self->add_relationship( |
75 | $rel, $rel_info->{source}, $rel_info->{cond}, |
76 | # extra key first to default it |
77 | {originally_defined_in => $source->name, %{$rel_info->{attrs}}}, |
78 | ); |
79 | } |
a010ebf9 |
80 | { no strict 'refs'; |
81 | push(@{$self->result_class.'::ISA'}, $source->result_class); |
82 | } |
803ffff2 |
83 | } |
84 | |
8b229aa6 |
85 | method _source_by_name ($name) { |
86 | my $schema = $self->schema; |
87 | my ($source) = |
88 | grep { $_->name eq $name } |
89 | map $schema->source($_), $schema->sources; |
90 | confess "Couldn't find attached source for parent $name - did you use load_classes? This module is only compatible with load_namespaces" |
91 | unless $source; |
92 | return $source; |
93 | } |
94 | |
7abe3af2 |
95 | method schema (@args) { |
96 | my $ret = $self->next::method(@args); |
97 | if (@args) { |
c73d582b |
98 | if ($self->parent_source) { |
c73d582b |
99 | my $parent_name = $self->parent_source->name; |
8b229aa6 |
100 | $self->parent_source($self->_source_by_name($parent_name)); |
c73d582b |
101 | } |
8b229aa6 |
102 | $self->additional_parents([ |
103 | map { $self->_source_by_name($_->name) } |
104 | @{$self->additional_parents||[]} |
105 | ]); |
7abe3af2 |
106 | } |
107 | return $ret; |
108 | } |
109 | |
c73d582b |
110 | method attach_additional_sources () { |
4d88a8d7 |
111 | my $raw_name = $self->raw_source_name; |
ca79850d |
112 | my $schema = $self->schema; |
113 | |
114 | # if the raw source is already present we can assume we're done |
115 | return if grep { $_ eq $raw_name } $schema->sources; |
4d88a8d7 |
116 | |
ca79850d |
117 | # our parent should've been registered already actually due to DBIC |
118 | # attaching subclass sources later in load_namespaces |
4d88a8d7 |
119 | |
ca79850d |
120 | my $parent; |
121 | if ($self->parent_source) { |
122 | my $parent_name = $self->parent_source->name; |
123 | ($parent) = |
124 | grep { $_->name eq $parent_name } |
125 | map $schema->source($_), $schema->sources; |
126 | confess "Couldn't find attached source for parent $parent_name - did you use load_classes? This module is only compatible with load_namespaces" |
127 | unless $parent; |
05fd2477 |
128 | $self->parent_source($parent); # so our parent is the one in this schema |
ca79850d |
129 | } |
4d88a8d7 |
130 | |
131 | # create the raw table source |
132 | |
133 | my $table = Table->new({ name => $self->raw_table_name }); |
134 | |
ca79850d |
135 | # we don't need to add the PK cols explicitly if we're the root table |
4d88a8d7 |
136 | # since they'll get added below |
137 | |
803ffff2 |
138 | my %pk_join; |
139 | |
ca79850d |
140 | if ($parent) { |
ca79850d |
141 | foreach my $pri ($self->primary_columns) { |
142 | my %info = %{$self->column_info($pri)}; |
143 | delete @info{qw(is_auto_increment sequence auto_nextval)}; |
7abe3af2 |
144 | $table->add_column($pri => \%info); |
803ffff2 |
145 | $pk_join{"foreign.${pri}"} = "self.${pri}"; |
ca79850d |
146 | } |
4d88a8d7 |
147 | # have to use source name lookups rather than result class here |
148 | # because we don't actually have a result class on the raw sources |
803ffff2 |
149 | $table->add_relationship('parent', $parent->raw_source_name, \%pk_join); |
c8e085ba |
150 | $self->deploy_depends_on->{$parent->result_class} = 1; |
803ffff2 |
151 | } |
152 | |
153 | foreach my $add (@{$self->additional_parents||[]}) { |
154 | $table->add_relationship( |
155 | 'parent_'.$add->name, $add->source_name, \%pk_join |
156 | ); |
c8e085ba |
157 | $self->deploy_depends_on->{$add->result_class} = 1; |
ca79850d |
158 | } |
4d88a8d7 |
159 | |
160 | # add every column that's actually a concrete part of us |
161 | |
162 | $table->add_columns( |
163 | map { ($_ => { %{$self->column_info($_)} }) } |
164 | grep { $self->column_info($_)->{originally_defined_in} eq $self->name } |
165 | $self->columns |
166 | ); |
ca79850d |
167 | $table->set_primary_key($self->primary_columns); |
490d5481 |
168 | |
169 | # we need to copy our rels to the raw object as well |
170 | # note that ->add_relationship on a source object doesn't create an |
171 | # accessor so we can leave that part in the attributes |
172 | |
173 | # if the other side is a table then we need to copy any rels it has |
174 | # back to us, as well, so that they point at the raw table. if the |
175 | # other side is an MTI view then we need to create the rels to it to |
176 | # point at -its- raw table; we don't need to worry about backrels because |
177 | # it's going to run this method too (and its raw source might not exist |
178 | # yet so we can't, anyway) |
179 | |
180 | foreach my $rel ($self->relationships) { |
181 | my $rel_info = $self->relationship_info($rel); |
182 | |
803ffff2 |
183 | # if we got this from the superclass, -its- raw table will nail this. |
184 | # if we got it from an additional parent, it's its problem. |
185 | next unless $rel_info->{attrs}{originally_defined_in} eq $self->name; |
186 | |
490d5481 |
187 | my $f_source = $schema->source($rel_info->{source}); |
188 | |
189 | # __PACKAGE__ is correct here because subclasses should be caught |
190 | |
191 | my $one_of_us = $f_source->isa(__PACKAGE__); |
192 | |
193 | my $f_source_name = $f_source->${\ |
194 | ($one_of_us ? 'raw_source_name' : 'source_name') |
195 | }; |
196 | |
197 | $table->add_relationship( |
198 | '_'.$rel, $f_source_name, @{$rel_info}{qw(cond attrs)} |
199 | ); |
200 | |
201 | unless ($one_of_us) { |
202 | my $reverse = do { |
203 | # we haven't been registered yet, so reverse_ cries |
204 | # XXX this is evil and will probably break eventually |
205 | local @{$schema->source_registrations} |
206 | {map $self->$_, qw(source_name result_class)} |
207 | = ($self, $self); |
208 | $self->reverse_relationship_info($rel); |
209 | }; |
210 | foreach my $rev_rel (keys %$reverse) { |
211 | $f_source->add_relationship( |
212 | '_raw_'.$rev_rel, $raw_name, @{$reverse->{$rev_rel}}{qw(cond attrs)} |
213 | ); |
214 | } |
215 | } |
216 | } |
217 | |
ca79850d |
218 | $schema->register_source($raw_name => $table); |
219 | } |
220 | |
221 | method set_primary_key (@args) { |
222 | if ($self->parent_source) { |
223 | confess "Can't set primary key on a subclass"; |
224 | } |
225 | return $self->next::method(@args); |
876f6525 |
226 | } |
227 | |
4d88a8d7 |
228 | method raw_source_name () { |
876f6525 |
229 | my $base = $self->source_name; |
05fd2477 |
230 | confess "Can't generate raw source name for ${\$self->name} when we don't have a source_name" |
876f6525 |
231 | unless $base; |
232 | return 'Raw::'.$base; |
233 | } |
70d56286 |
234 | |
4d88a8d7 |
235 | method raw_table_name () { |
236 | return '_'.$self->name; |
237 | } |
238 | |
876f6525 |
239 | method add_columns (@args) { |
240 | my $ret = $self->next::method(@args); |
241 | $_->{originally_defined_in} ||= $self->name for values %{$self->_columns}; |
242 | return $ret; |
70d56286 |
243 | } |
244 | |
803ffff2 |
245 | method add_relationship ($name, $f_source, $cond, $attrs) { |
246 | $self->next::method( |
247 | $name, $f_source, $cond, |
248 | { originally_defined_in => $self->name, %{$attrs||{}}, } |
249 | ); |
250 | } |
251 | |
487f4489 |
252 | BEGIN { |
253 | |
254 | # helper routines, constructed as anon subs so autoclean nukes them |
255 | |
256 | use signatures; |
257 | |
258 | *argify = sub (@names) { |
259 | map '_'.$_, @names; |
260 | }; |
261 | |
262 | *qualify_with = sub ($source, @names) { |
92ebfc06 |
263 | my $name = blessed($source) ? $source->name : $source; |
264 | map join('.', $name, $_), @names; |
487f4489 |
265 | }; |
266 | |
267 | *body_cols = sub ($source) { |
268 | my %pk; @pk{$source->primary_columns} = (); |
269 | map +{ %{$source->column_info($_)}, name => $_ }, |
270 | grep !exists $pk{$_}, $source->columns; |
271 | }; |
272 | |
273 | *pk_cols = sub ($source) { |
274 | map +{ %{$source->column_info($_)}, name => $_ }, |
275 | $source->primary_columns; |
276 | }; |
277 | |
92ebfc06 |
278 | *names_of = sub (@cols) { map $_->{name}, @cols }; |
487f4489 |
279 | |
c8e085ba |
280 | *function_body = sub { |
281 | my ($name,$args,$body_parts) = @_; |
05fd2477 |
282 | my $arglist = join( |
283 | ', ', |
388d83fc |
284 | map "_${\$_->{name}} ${\uc($_->{data_type})}", |
05fd2477 |
285 | @$args |
286 | ); |
287 | my $body = join("\n", '', map " $_;", @$body_parts); |
288 | return strip tt q{ |
289 | CREATE OR REPLACE FUNCTION [% name %] |
290 | ([% arglist %]) |
291 | RETURNS VOID AS $function$ |
292 | BEGIN |
293 | [%- body %] |
294 | END; |
295 | $function$ LANGUAGE plpgsql; |
296 | }; |
487f4489 |
297 | }; |
c8e085ba |
298 | #*function_body = sub ($name,$args,$body_parts) { |
299 | #my $arglist = join( |
300 | #', ', |
301 | #map "_${\$_->{name}} ${\uc($_->{data_type})}", |
302 | #@$args |
303 | #); |
304 | #my $body = join("\n", '', map " $_;", @$body_parts); |
305 | #return strip tt q{ |
306 | #CREATE OR REPLACE FUNCTION [% name %] |
307 | #([% arglist %]) |
308 | #RETURNS VOID AS $function$ |
309 | #BEGIN |
310 | #[%- body %] |
311 | #END; |
312 | #$function$ LANGUAGE plpgsql; |
313 | #}; |
314 | #}; |
487f4489 |
315 | } |
316 | |
05fd2477 |
317 | BEGIN { |
318 | |
319 | use signatures; |
320 | |
321 | *arg_hash = sub ($source) { |
322 | map +($_ => \(argify $_)), names_of body_cols $source; |
323 | }; |
92ebfc06 |
324 | |
325 | *rule_body = sub ($on, $to, $oldlist, $newlist) { |
326 | my $arglist = join(', ', |
327 | (qualify_with 'OLD', names_of @$oldlist), |
328 | (qualify_with 'NEW', names_of @$newlist), |
329 | ); |
330 | $to = $to->name if blessed($to); |
331 | return strip tt q{ |
332 | CREATE RULE _[% to %]_[% on %]_rule AS |
333 | ON [% on | upper %] TO [% to %] |
334 | DO INSTEAD ( |
3c259cfb |
335 | SELECT [% to %]_[% on %]([% arglist %]) |
92ebfc06 |
336 | ); |
337 | }; |
338 | }; |
05fd2477 |
339 | } |
340 | |
341 | method root_table () { |
342 | $self->parent_source |
343 | ? $self->parent_source->root_table |
344 | : $self->schema->source($self->raw_source_name) |
345 | } |
346 | |
487f4489 |
347 | method view_definition () { |
348 | my $schema = $self->schema; |
349 | confess "Can't generate view without connected schema, sorry" |
350 | unless $schema && $schema->storage; |
351 | my $sqla = $schema->storage->sql_maker; |
2816c8ed |
352 | my $table = $self->schema->source($self->raw_source_name); |
487f4489 |
353 | my $super_view = $self->parent_source; |
2816c8ed |
354 | my @all_parents = my @other_parents = @{$self->additional_parents||[]}; |
355 | push(@all_parents, $super_view) if defined($super_view); |
356 | my @sources = ($table, @all_parents); |
487f4489 |
357 | my @body_cols = map body_cols($_), @sources; |
358 | my @pk_cols = pk_cols $self; |
92ebfc06 |
359 | |
360 | # SELECT statement |
361 | |
2816c8ed |
362 | my $am_root = !($super_view || @other_parents); |
363 | |
487f4489 |
364 | my $select = $sqla->select( |
2816c8ed |
365 | ($am_root |
366 | ? ($table->name) |
367 | : ([ # FROM _tbl _tbl |
487f4489 |
368 | { $table->name => $table->name }, |
2816c8ed |
369 | map { |
370 | my $parent = $_; |
371 | [ # JOIN view view |
372 | { $parent->name => $parent->name }, |
373 | # ON _tbl.id = view.id |
374 | { map +(qualify_with($parent, $_), qualify_with($table, $_)), |
375 | names_of @pk_cols } |
376 | ] |
377 | } @all_parents |
487f4489 |
378 | ]) |
2816c8ed |
379 | ), |
487f4489 |
380 | [ (qualify_with $table, names_of @pk_cols), names_of @body_cols ], |
05fd2477 |
381 | ).';'; |
92ebfc06 |
382 | |
2816c8ed |
383 | my ($now, @next) = grep defined, $super_view, $table, @other_parents; |
92ebfc06 |
384 | |
385 | # INSERT function |
386 | |
05fd2477 |
387 | # NOTE: this assumes a single PK col called id with a sequence somewhere |
388 | # but nothing else -should- so fixing this should make everything work |
389 | my $insert_func = |
c8e085ba |
390 | function_body |
05fd2477 |
391 | $self->name.'_insert', |
392 | \@body_cols, |
393 | [ |
2816c8ed |
394 | $sqla->insert( # INSERT INTO tbl/super_view (foo, ...) VALUES (_foo, ...) |
05fd2477 |
395 | $now->name, |
396 | { arg_hash $now }, |
397 | ), |
2816c8ed |
398 | (map { |
399 | $sqla->insert( # INSERT INTO parent (id, ...) |
400 | # VALUES (currval('_root_tbl_id_seq'), ...) |
401 | $_->name, |
402 | { |
403 | (arg_hash $_), |
404 | id => \"currval('${\$self->root_table->name}_id_seq')", |
405 | } |
406 | ) |
407 | } @next) |
05fd2477 |
408 | ]; |
92ebfc06 |
409 | |
05fd2477 |
410 | # note - similar to arg_hash but not quite enough to share code sanely |
411 | my $pk_where = { # id = _id AND id2 = _id2 ... |
412 | map +($_ => \"= ${\argify $_}"), names_of @pk_cols |
413 | }; |
92ebfc06 |
414 | |
415 | # UPDATE function |
416 | |
05fd2477 |
417 | my $update_func = |
c8e085ba |
418 | function_body |
05fd2477 |
419 | $self->name.'_update', |
420 | [ @pk_cols, @body_cols ], |
421 | [ map $sqla->update( |
422 | $_->name, # UPDATE foo |
423 | { arg_hash $_ }, # SET a = _a |
424 | $pk_where, |
425 | ), @sources |
426 | ]; |
92ebfc06 |
427 | |
428 | # DELETE function |
429 | |
05fd2477 |
430 | my $delete_func = |
c8e085ba |
431 | function_body |
05fd2477 |
432 | $self->name.'_delete', |
433 | [ @pk_cols ], |
434 | [ map $sqla->delete($_->name, $pk_where), @sources ]; |
92ebfc06 |
435 | |
436 | my @rules = ( |
437 | (rule_body insert => $self, [], \@body_cols), |
438 | (rule_body update => $self, \@pk_cols, \@body_cols), |
439 | (rule_body delete => $self, \@pk_cols, []), |
440 | ); |
441 | return join("\n\n", $select, $insert_func, $update_func, $delete_func, @rules); |
487f4489 |
442 | } |
443 | |
70d56286 |
444 | 1; |
146ec120 |
445 | |
446 | __END__ |
f5c54951 |
447 | |
146ec120 |
448 | =head1 NAME |
449 | |
f5c54951 |
450 | DBIx::Class::ResultSource::MultipleTableInheritance |
451 | Use multiple tables to define your classes |
452 | |
453 | =head1 NOTICE |
454 | |
455 | This only works with PostgreSQL for the moment. |
146ec120 |
456 | |
457 | =head1 SYNOPSIS |
458 | |
146ec120 |
459 | { |
f8864134 |
460 | package Cafe::Result::Coffee; |
146ec120 |
461 | |
f8864134 |
462 | use strict; |
463 | use warnings; |
464 | use parent 'DBIx::Class::Core'; |
465 | use aliased 'DBIx::Class::ResultSource::MultipleTableInheritance' |
466 | => 'MTI'; |
467 | |
468 | __PACKAGE__->table_class(MTI); |
146ec120 |
469 | __PACKAGE__->table('coffee'); |
470 | __PACKAGE__->add_columns( |
f8864134 |
471 | "id", { data_type => "integer" }, |
472 | "flavor", { |
473 | data_type => "text", |
474 | default_value => "good" }, |
146ec120 |
475 | ); |
476 | |
477 | __PACKAGE__->set_primary_key("id"); |
478 | |
479 | 1; |
480 | } |
481 | |
482 | { |
f8864134 |
483 | package Cafe::Result::Sumatra; |
146ec120 |
484 | |
f8864134 |
485 | use parent 'Cafe::Result::Coffee'; |
146ec120 |
486 | |
487 | __PACKAGE__->table('sumatra'); |
488 | |
f8864134 |
489 | __PACKAGE__->add_columns( "aroma", |
490 | { data_type => "text" } |
146ec120 |
491 | ); |
492 | |
493 | 1; |
494 | } |
495 | |
496 | ... |
497 | |
f8864134 |
498 | my $schema = Cafe->connect($dsn,$user,$pass); |
146ec120 |
499 | |
f8864134 |
500 | my $cup = $schema->resultset('Sumatra'); |
146ec120 |
501 | |
f8864134 |
502 | print STDERR Dwarn $cup->result_source->columns; |
146ec120 |
503 | |
f8864134 |
504 | "id" |
505 | "flavor" |
506 | "aroma" |
507 | .. |
146ec120 |
508 | |
f5c54951 |
509 | Inherit from this package and you can make a resultset class from a view, but |
510 | that's more than a little bit misleading: the result is B<transparently |
511 | writable>. |
146ec120 |
512 | |
f5c54951 |
513 | This is accomplished through the use of stored procedures that map changes |
514 | written to the view to changes to the underlying concrete tables. |
146ec120 |
515 | |
516 | =head1 WHY? |
517 | |
f5c54951 |
518 | In many applications, many classes are subclasses of others. Let's say you |
519 | have this schema: |
146ec120 |
520 | |
521 | # Conceptual domain model |
522 | |
523 | class User { |
f5c54951 |
524 | has id, |
525 | has name, |
526 | has password |
146ec120 |
527 | } |
528 | |
529 | class Investor { |
530 | has id, |
531 | has name, |
532 | has password, |
533 | has dollars |
534 | } |
535 | |
536 | That's redundant. Hold on a sec... |
537 | |
538 | class User { |
f5c54951 |
539 | has id, |
540 | has name, |
541 | has password |
146ec120 |
542 | } |
543 | |
e7189506 |
544 | class Investor extends User { |
146ec120 |
545 | has dollars |
546 | } |
547 | |
548 | Good idea, but how to put this into code? |
549 | |
f5c54951 |
550 | One far-too common and absolutely horrendous solution is to have a "checkbox" |
551 | in your database: a nullable "investor" column, which entails a nullable |
552 | "dollars" column, in the user table. |
146ec120 |
553 | |
554 | create table "user" ( |
555 | "id" integer not null primary key autoincrement, |
556 | "name" text not null, |
557 | "password" text not null, |
558 | "investor" tinyint(1), |
559 | "dollars" integer |
560 | ); |
561 | |
562 | Let's not discuss that further. |
563 | |
f5c54951 |
564 | A second, better, solution is to break out the two tables into user and |
565 | investor: |
146ec120 |
566 | |
567 | create table "user" ( |
568 | "id" integer not null primary key autoincrement, |
569 | "name" text not null, |
570 | "password" text not null |
571 | ); |
572 | |
573 | create table "investor" ( |
574 | "id" integer not null references user("id"), |
575 | "dollars" integer |
576 | ); |
577 | |
f5c54951 |
578 | So that investor's PK is just an FK to the user. We can clearly see the class |
579 | hierarchy here, in which investor is a subclass of user. In DBIx::Class |
580 | applications, this second strategy looks like: |
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581 | |
582 | my $user_rs = $schema->resultset('User'); |
583 | my $new_user = $user_rs->create( |
584 | name => $args->{name}, |
585 | password => $args->{password}, |
586 | ); |
587 | |
588 | ... |
589 | |
590 | my $new_investor = $schema->resultset('Investor')->create( |
591 | id => $new_user->id, |
592 | dollars => $args->{dollars}, |
593 | ); |
594 | |
f5c54951 |
595 | One can cope well with the second strategy, and it seems to be the most popular |
596 | smart choice. |
e7189506 |
597 | |
146ec120 |
598 | =head1 HOW? |
599 | |
f5c54951 |
600 | There is a third strategy implemented here. Make the database do more of the |
601 | work: hide the nasty bits so we don't have to handle them unless we really want |
602 | to. It'll save us some typing and it'll make for more expressive code. What if |
603 | we could do this: |
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604 | |
605 | my $new_investor = $schema->resultset('Investor')->create( |
606 | name => $args->{name}, |
607 | password => $args->{password}, |
608 | dollars => $args->{dollars}, |
609 | ); |
610 | |
e7189506 |
611 | And have it Just Work? The user... |
612 | |
613 | { |
614 | name => $args->{name}, |
615 | password => $args->{password}, |
616 | } |
617 | |
f5c54951 |
618 | should be created behind the scenes, and the use of either user or investor |
619 | in your code should require no special handling. Deleting and updating |
620 | $new_investor should also delete or update the user row. |
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621 | |
f5c54951 |
622 | It does. User and investor are both views, their concrete tables abstracted |
623 | away behind a set of rules and triggers. You would expect the above DBIC |
624 | create statement to look like this in SQL: |
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625 | |
626 | INSERT INTO investor ("name","password","dollars") VALUES (...); |
627 | |
628 | But using MTI, it is really this: |
629 | |
630 | INSERT INTO _user_table ("username","password") VALUES (...); |
631 | INSERT INTO _investor_table ("id","dollars") VALUES (currval('_user_table_id_seq',...) ); |
632 | |
f5c54951 |
633 | For deletes, the triggers fire in reverse, to preserve referential integrity |
634 | (foreign key constraints). For instance: |
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635 | |
636 | my $investor = $schema->resultset('Investor')->find({id => $args->{id}}); |
637 | $investor->delete; |
638 | |
639 | Becomes: |
640 | |
641 | DELETE FROM _investor_table WHERE ("id" = ?); |
642 | DELETE FROM _user_table WHERE ("id" = ?); |
643 | |
644 | |
e7189506 |
645 | =head1 METHODS |
646 | |
647 | =over |
648 | |
649 | =item new |
650 | |
651 | |
f5c54951 |
652 | MTI find the parents, if any, of your resultset class and adds them to the |
653 | list of parent_sources for the table. |
e7189506 |
654 | |
655 | |
656 | =item add_additional_parents |
657 | |
658 | |
659 | Continuing with coffee: |
660 | |
661 | __PACKAGE__->result_source_instance->add_additional_parents( |
662 | qw/ |
663 | MyApp::Schema::Result::Beverage |
664 | MyApp::Schema::Result::Liquid |
665 | / |
666 | ); |
667 | |
668 | This just lets you manually add additional parents beyond the ones MTI finds. |
669 | |
670 | =item add_additional_parent |
671 | |
672 | __PACKAGE__->result_source_instance->add_additional_parent( |
673 | MyApp::Schema::Result::Beverage |
674 | ); |
675 | |
676 | You can also add just one. |
677 | |
678 | =item attach_additional_sources |
679 | |
f5c54951 |
680 | MTI takes the parents' sources and relationships, creates a new |
681 | DBIx::Class::Table object from them, and registers this as a new, raw, source |
682 | in the schema, e.g., |
e7189506 |
683 | |
684 | use MyApp::Schema; |
685 | |
686 | print STDERR map { "$_\n" } MyApp::Schema->sources; |
687 | |
688 | # Coffee |
689 | # Beverage |
690 | # Liquid |
691 | # Sumatra |
692 | # Raw::Sumatra |
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693 | |
e7189506 |
694 | Raw::Sumatra will be used to generate the view. |
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695 | |
e7189506 |
696 | =item view_definition |
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697 | |
e7189506 |
698 | This takes the raw table and generates the view (and stored procedures) you will use. |
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699 | |
e7189506 |
700 | =back |
146ec120 |
701 | |
702 | =head1 AUTHOR |
703 | |
704 | Matt S. Trout, E<lt>mst@shadowcatsystems.co.ukE<gt> |
705 | |
706 | =head2 CONTRIBUTORS |
707 | |
f5c54951 |
708 | Amiri Barksdale, E<lt>amiri@metalabel.comE<gt> |
709 | |
710 | =head1 COPYRIGHT |
711 | |
712 | Copyright (c) 2010 the DBIx::Class::ResultSource::MultipleTableInheritance |
713 | L</AUTHOR> and L</CONTRIBUTORS> as listed above. |
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714 | |
715 | =head1 LICENSE |
716 | |
717 | This library is free software; you can redistribute it and/or modify |
718 | it under the same terms as Perl itself. |
719 | |
720 | =head1 SEE ALSO |
721 | |
722 | L<DBIx::Class> |
723 | L<DBIx::Class::ResultSource> |
724 | |
725 | =cut |