1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
|
require 'active_record/associations/association_collection'
require 'active_record/associations/has_many_association'
require 'active_record/associations/has_and_belongs_to_many_association'
require 'active_record/deprecated_associations'
class << Object #:nodoc:
# Make require_association available as a bare method.
unless respond_to?(:require_association)
def require_association(file_name)
ActiveRecord::Base.require_association(file_name)
end
end
# Use const_missing to autoload associations so we don't have to
# require_association when using single-table inheritance.
unless respond_to?(:pre_association_const_missing)
alias_method :pre_association_const_missing, :const_missing
def const_missing(class_id)
begin
require_association(Inflect.underscore(Inflector.demodulize(class_id.to_s)))
rescue LoadError
pre_association_const_missing(class_id)
end
end
end
end
module ActiveRecord
module Associations # :nodoc:
def self.append_features(base)
super
base.extend(ClassMethods)
end
# Associations are a set of macro-like class methods for tying objects together through foreign keys. They express relationships like
# "Project has one Project Manager" or "Project belongs to a Portfolio". Each macro adds a number of methods to the class which are
# specialized according to the collection or association symbol and the options hash. It works much the same was as Ruby's own attr*
# methods. Example:
#
# class Project < ActiveRecord::Base
# belongs_to :portfolio
# has_one :project_manager
# has_many :milestones
# has_and_belongs_to_many :categories
# end
#
# The project class now has the following methods (and more) to ease the traversal and manipulation of its relationships:
# * <tt>Project#portfolio, Project#portfolio=(portfolio), Project#portfolio.nil?, Project#portfolio?(portfolio)</tt>
# * <tt>Project#project_manager, Project#project_manager=(project_manager), Project#project_manager.nil?,</tt>
# <tt>Project#project_manager?(project_manager), Project#build_project_manager, Project#create_project_manager</tt>
# * <tt>Project#milestones.empty?, Project#milestones.size, Project#milestones, Project#milestones<<(milestone),</tt>
# <tt>Project#milestones.delete(milestone), Project#milestones.find(milestone_id), Project#milestones.find_all(conditions),</tt>
# <tt>Project#milestones.build, Project#milestones.create</tt>
# * <tt>Project#categories.empty?, Project#categories.size, Project#categories, Project#categories<<(category1),</tt>
# <tt>Project#categories.delete(category1)</tt>
#
# == Example
#
# link:../examples/associations.png
#
# == Is it belongs_to or has_one?
#
# Both express a 1-1 relationship, the difference is mostly where to place the foreign key, which goes on the table for the class
# saying belongs_to. Example:
#
# class Post < ActiveRecord::Base
# has_one :author
# end
#
# class Author < ActiveRecord::Base
# belongs_to :post
# end
#
# The tables for these classes could look something like:
#
# CREATE TABLE posts (
# id int(11) NOT NULL auto_increment,
# title varchar default NULL,
# PRIMARY KEY (id)
# )
#
# CREATE TABLE authors (
# id int(11) NOT NULL auto_increment,
# post_id int(11) default NULL,
# name varchar default NULL,
# PRIMARY KEY (id)
# )
#
# == Caching
#
# All of the methods are built on a simple caching principle that will keep the result of the last query around unless specifically
# instructed not to. The cache is even shared across methods to make it even cheaper to use the macro-added methods without
# worrying too much about performance at the first go. Example:
#
# project.milestones # fetches milestones from the database
# project.milestones.size # uses the milestone cache
# project.milestones.empty? # uses the milestone cache
# project.milestones(true).size # fetches milestones from the database
# project.milestones # uses the milestone cache
#
# == Modules
#
# By default, associations will look for objects within the current module scope. Consider:
#
# module MyApplication
# module Business
# class Firm < ActiveRecord::Base
# has_many :clients
# end
#
# class Company < ActiveRecord::Base; end
# end
# end
#
# When Firm#clients is called, it'll in turn call <tt>MyApplication::Business::Company.find(firm.id)</tt>. If you want to associate
# with a class in another module scope this can be done by specifying the complete class name, such as:
#
# module MyApplication
# module Business
# class Firm < ActiveRecord::Base; end
# end
#
# module Billing
# class Account < ActiveRecord::Base
# belongs_to :firm, :class_name => "MyApplication::Business::Firm"
# end
# end
# end
#
# == Type safety with ActiveRecord::AssociationTypeMismatch
#
# If you attempt to assign an object to an association that doesn't match the inferred or specified <tt>:class_name</tt>, you'll
# get a ActiveRecord::AssociationTypeMismatch.
#
# == Options
#
# All of the association macros can be specialized through options which makes more complex cases than the simple and guessable ones
# possible.
module ClassMethods
# Adds the following methods for retrival and query of collections of associated objects.
# +collection+ is replaced with the symbol passed as the first argument, so
# <tt>has_many :clients</tt> would add among others <tt>has_clients?</tt>.
# * <tt>collection(force_reload = false)</tt> - returns an array of all the associated objects.
# An empty array is returned if none are found.
# * <tt>collection<<(object, ...)</tt> - adds one or more objects to the collection by setting their foreign keys to the collection's primary key.
# * <tt>collection.delete(object, ...)</tt> - removes one or more objects from the collection by setting their foreign keys to NULL. This does not destroy the objects.
# * <tt>collection.clear</tt> - removes every object from the collection. This does not destroy the objects.
# * <tt>collection.empty?</tt> - returns true if there are no associated objects.
# * <tt>collection.size</tt> - returns the number of associated objects.
# * <tt>collection.find(id)</tt> - finds an associated object responding to the +id+ and that
# meets the condition that it has to be associated with this object.
# * <tt>collection.find_all(conditions = nil, orderings = nil, limit = nil, joins = nil)</tt> - finds all associated objects responding
# criterias mentioned (like in the standard find_all) and that meets the condition that it has to be associated with this object.
# * <tt>collection.build(attributes = {})</tt> - returns a new object of the collection type that has been instantiated
# with +attributes+ and linked to this object through a foreign key but has not yet been saved.
# * <tt>collection.create(attributes = {})</tt> - returns a new object of the collection type that has been instantiated
# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
#
# Example: A Firm class declares <tt>has_many :clients</tt>, which will add:
# * <tt>Firm#clients</tt> (similar to <tt>Clients.find_all "firm_id = #{id}"</tt>)
# * <tt>Firm#clients<<</tt>
# * <tt>Firm#clients.delete</tt>
# * <tt>Firm#clients.clear</tt>
# * <tt>Firm#clients.empty?</tt> (similar to <tt>firm.clients.size == 0</tt>)
# * <tt>Firm#clients.size</tt> (similar to <tt>Client.count "firm_id = #{id}"</tt>)
# * <tt>Firm#clients.find</tt> (similar to <tt>Client.find_on_conditions(id, "firm_id = #{id}")</tt>)
# * <tt>Firm#clients.find_all</tt> (similar to <tt>Client.find_all "firm_id = #{id}"</tt>)
# * <tt>Firm#clients.build</tt> (similar to <tt>Client.new("firm_id" => id)</tt>)
# * <tt>Firm#clients.create</tt> (similar to <tt>c = Client.new("client_id" => id); c.save; c</tt>)
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# from the association name. So <tt>has_many :products</tt> will by default be linked to the +Product+ class, but
# if the real class name is +SpecialProduct+, you'll have to specify it with this option.
# * <tt>:conditions</tt> - specify the conditions that the associated objects must meet in order to be included as a "WHERE"
# sql fragment, such as "price > 5 AND name LIKE 'B%'".
# * <tt>:order</tt> - specify the order in which the associated objects are returned as a "ORDER BY" sql fragment,
# such as "last_name, first_name DESC"
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_many association will use "person_id"
# as the default foreign_key.
# * <tt>:dependent</tt> - if set to true all the associated object are destroyed alongside this object.
# May not be set if :exclusively_dependent is also set.
# * <tt>:exclusively_dependent</tt> - if set to true all the associated object are deleted in one SQL statement without having their
# before_destroy callback run. This should only be used on associations that depend solely on this class and don't need to do any
# clean-up in before_destroy. The upside is that it's much faster, especially if there's a counter_cache involved.
# May not be set if :dependent is also set.
# * <tt>:finder_sql</tt> - specify a complete SQL statement to fetch the association. This is a good way to go for complex
# associations that depends on multiple tables. Note: When this option is used, +find_in_collection+ is _not_ added.
# * <tt>:counter_sql</tt> - specify a complete SQL statement to fetch the size of the association. If +:finder_sql+ is
# specified but +:counter_sql+, +:counter_sql+ will be generated by replacing SELECT ... FROM with SELECT COUNT(*) FROM.
#
# Option examples:
# has_many :comments, :order => "posted_on"
# has_many :people, :class_name => "Person", :conditions => "deleted = 0", :order => "name"
# has_many :tracks, :order => "position", :dependent => true
# has_many :subscribers, :class_name => "Person", :finder_sql =>
# 'SELECT DISTINCT people.* ' +
# 'FROM people p, post_subscriptions ps ' +
# 'WHERE ps.post_id = #{id} AND ps.person_id = p.id ' +
# 'ORDER BY p.first_name'
def has_many(association_id, options = {})
validate_options([ :foreign_key, :class_name, :exclusively_dependent, :dependent, :conditions, :order, :finder_sql, :counter_sql ], options.keys)
association_name, association_class_name, association_class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key])
require_association_class(association_class_name)
if options[:dependent] and options[:exclusively_dependent]
raise ArgumentError, ':dependent and :exclusively_dependent are mutually exclusive options. You may specify one or the other.' # ' ruby-mode
elsif options[:dependent]
module_eval "before_destroy '#{association_name}.each { |o| o.destroy }'"
elsif options[:exclusively_dependent]
module_eval "before_destroy { |record| #{association_class_name}.delete_all(%(#{association_class_primary_key_name} = \#{record.quoted_id})) }"
end
define_method(association_name) do |*params|
force_reload = params.first unless params.empty?
association = instance_variable_get("@#{association_name}")
if association.nil?
association = HasManyAssociation.new(self,
association_name, association_class_name,
association_class_primary_key_name, options)
instance_variable_set("@#{association_name}", association)
end
association.reload if force_reload
association
end
# deprecated api
deprecated_collection_count_method(association_name)
deprecated_add_association_relation(association_name)
deprecated_remove_association_relation(association_name)
deprecated_has_collection_method(association_name)
deprecated_find_in_collection_method(association_name)
deprecated_find_all_in_collection_method(association_name)
deprecated_create_method(association_name)
deprecated_build_method(association_name)
end
# Adds the following methods for retrival and query of a single associated object.
# +association+ is replaced with the symbol passed as the first argument, so
# <tt>has_one :manager</tt> would add among others <tt>has_manager?</tt>.
# * <tt>association(force_reload = false)</tt> - returns the associated object. Nil is returned if none is found.
# * <tt>association=(associate)</tt> - assigns the associate object, extracts the primary key, sets it as the foreign key,
# and saves the associate object.
# * <tt>association?(object, force_reload = false)</tt> - returns true if the +object+ is of the same type and has the
# same id as the associated object.
# * <tt>association.nil?</tt> - returns true if there is no associated object.
# * <tt>build_association(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
# with +attributes+ and linked to this object through a foreign key but has not yet been saved.
# * <tt>create_association(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
#
# Example: An Account class declares <tt>has_one :beneficiary</tt>, which will add:
# * <tt>Account#beneficiary</tt> (similar to <tt>Beneficiary.find_first "account_id = #{id}"</tt>)
# * <tt>Account#beneficiary=(beneficiary)</tt> (similar to <tt>beneficiary.account_id = account.id; beneficiary.save</tt>)
# * <tt>Account#beneficiary?</tt> (similar to <tt>account.beneficiary == some_beneficiary</tt>)
# * <tt>Account#beneficiary.nil?</tt>
# * <tt>Account#build_beneficiary</tt> (similar to <tt>Beneficiary.new("account_id" => id)</tt>)
# * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>)
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# from the association name. So <tt>has_one :manager</tt> will by default be linked to the +Manager+ class, but
# if the real class name is +Person+, you'll have to specify it with this option.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "rank = 5".
# * <tt>:order</tt> - specify the order from which the associated object will be picked at the top. Specified as
# an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:dependent</tt> - if set to true the associated object is destroyed alongside this object
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_one association will use "person_id"
# as the default foreign_key.
#
# Option examples:
# has_one :credit_card, :dependent => true
# has_one :last_comment, :class_name => "Comment", :order => "posted_on"
# has_one :project_manager, :class_name => "Person", :conditions => "role = 'project_manager'"
def has_one(association_id, options = {})
options.merge!({ :remote => true })
belongs_to(association_id, options)
association_name, association_class_name, class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key], false)
require_association_class(association_class_name)
has_one_writer_method(association_name, association_class_name, class_primary_key_name)
build_method("build_", association_name, association_class_name, class_primary_key_name)
create_method("create_", association_name, association_class_name, class_primary_key_name)
module_eval "before_destroy '#{association_name}.destroy if has_#{association_name}?'" if options[:dependent]
end
# Adds the following methods for retrival and query for a single associated object that this object holds an id to.
# +association+ is replaced with the symbol passed as the first argument, so
# <tt>belongs_to :author</tt> would add among others <tt>has_author?</tt>.
# * <tt>association(force_reload = false)</tt> - returns the associated object. Nil is returned if none is found.
# * <tt>association=(associate)</tt> - assigns the associate object, extracts the primary key, and sets it as the foreign key.
# * <tt>association?(object, force_reload = false)</tt> - returns true if the +object+ is of the same type and has the
# same id as the associated object.
# * <tt>association.nil?</tt> - returns true if there is no associated object.
#
# Example: An Post class declares <tt>has_one :author</tt>, which will add:
# * <tt>Post#author</tt> (similar to <tt>Author.find(author_id)</tt>)
# * <tt>Post#author=(author)</tt> (similar to <tt>post.author_id = author.id</tt>)
# * <tt>Post#author?</tt> (similar to <tt>post.author == some_author</tt>)
# * <tt>Post#author.nil?</tt>
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# from the association name. So <tt>has_one :author</tt> will by default be linked to the +Author+ class, but
# if the real class name is +Person+, you'll have to specify it with this option.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "authorized = 1".
# * <tt>:order</tt> - specify the order from which the associated object will be picked at the top. Specified as
# an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of the associated class in lower-case and "_id" suffixed. So a +Person+ class that makes a belongs_to association to a
# +Boss+ class will use "boss_id" as the default foreign_key.
# * <tt>:counter_cache</tt> - caches the number of belonging objects on the associate class through use of increment_counter
# and decrement_counter. The counter cache is incremented when an object of this class is created and decremented when it's
# destroyed. This requires that a column named "#{table_name}_count" (such as comments_count for a belonging Comment class)
# is used on the associate class (such as a Post class).
#
# Option examples:
# belongs_to :firm, :foreign_key => "client_of"
# belongs_to :author, :class_name => "Person", :foreign_key => "author_id"
# belongs_to :valid_coupon, :class_name => "Coupon", :foreign_key => "coupon_id",
# :conditions => 'discounts > #{payments_count}'
def belongs_to(association_id, options = {})
validate_options([ :class_name, :foreign_key, :remote, :conditions, :order, :dependent, :counter_cache ], options.keys)
association_name, association_class_name, class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key], false)
require_association_class(association_class_name)
association_class_primary_key_name = options[:foreign_key] || Inflector.underscore(Inflector.demodulize(association_class_name)) + "_id"
if options[:remote]
association_finder = <<-"end_eval"
#{association_class_name}.find_first(
"#{class_primary_key_name} = \#{quoted_id}#{options[:conditions] ? " AND " + options[:conditions] : ""}",
#{options[:order] ? "\"" + options[:order] + "\"" : "nil" }
)
end_eval
else
association_finder = options[:conditions] ?
"#{association_class_name}.find_on_conditions(#{association_class_primary_key_name}, \"#{options[:conditions]}\")" :
"#{association_class_name}.find(#{association_class_primary_key_name})"
end
has_association_method(association_name)
association_reader_method(association_name, association_finder)
belongs_to_writer_method(association_name, association_class_name, association_class_primary_key_name)
association_comparison_method(association_name, association_class_name)
if options[:counter_cache]
module_eval(
"after_create '#{association_class_name}.increment_counter(\"#{Inflector.pluralize(self.to_s.downcase). + "_count"}\", #{association_class_primary_key_name})" +
" if has_#{association_name}?'"
)
module_eval(
"before_destroy '#{association_class_name}.decrement_counter(\"#{Inflector.pluralize(self.to_s.downcase) + "_count"}\", #{association_class_primary_key_name})" +
" if has_#{association_name}?'"
)
end
end
# Associates two classes via an intermediate join table. Unless the join table is explicitly specified as
# an option, it is guessed using the lexical order of the class names. So a join between Developer and Project
# will give the default join table name of "developers_projects" because "D" outranks "P".
#
# Any additional fields added to the join table will be placed as attributes when pulling records out through
# has_and_belongs_to_many associations. This is helpful when have information about the association itself
# that you want available on retrival.
#
# Adds the following methods for retrival and query.
# +collection+ is replaced with the symbol passed as the first argument, so
# <tt>has_and_belongs_to_many :categories</tt> would add among others +add_categories+.
# * <tt>collection(force_reload = false)</tt> - returns an array of all the associated objects.
# An empty array is returned if none is found.
# * <tt>collection<<(object, ...)</tt> - adds one or more objects to the collection by creating associations in the join table
# (collection.push and collection.concat are aliases to this method).
# * <tt>collection.push_with_attributes(object, join_attributes)</tt> - adds one to the collection by creating an association in the join table that
# also holds the attributes from <tt>join_attributes</tt> (should be a hash with the column names as keys). This can be used to have additional
# attributes on the join, which will be injected into the associated objects when they are retrieved through the collection.
# (collection.concat_with_attributes is an alias to this method).
# * <tt>collection.delete(object, ...)</tt> - removes one or more objects from the collection by removing their associations from the join table.
# This does not destroy the objects.
# * <tt>collection.clear</tt> - removes every object from the collection. This does not destroy the objects.
# * <tt>collection.empty?</tt> - returns true if there are no associated objects.
# * <tt>collection.size</tt> - returns the number of associated objects.
#
# Example: An Developer class declares <tt>has_and_belongs_to_many :projects</tt>, which will add:
# * <tt>Developer#projects</tt>
# * <tt>Developer#projects<<</tt>
# * <tt>Developer#projects.delete</tt>
# * <tt>Developer#projects.clear</tt>
# * <tt>Developer#projects.empty?</tt>
# * <tt>Developer#projects.size</tt>
# * <tt>Developer#projects.find(id)</tt>
# The declaration may include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# from the association name. So <tt>has_and_belongs_to_many :projects</tt> will by default be linked to the
# +Project+ class, but if the real class name is +SuperProject+, you'll have to specify it with this option.
# * <tt>:join_table</tt> - specify the name of the join table if the default based on lexical order isn't what you want.
# WARNING: If you're overwriting the table name of either class, the table_name method MUST be declared underneath any
# has_and_belongs_to_many declaration in order to work.
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_and_belongs_to_many association
# will use "person_id" as the default foreign_key.
# * <tt>:association_foreign_key</tt> - specify the association foreign key used for the association. By default this is
# guessed to be the name of the associated class in lower-case and "_id" suffixed. So the associated class is +Project+
# that makes a has_and_belongs_to_many association will use "project_id" as the default association foreign_key.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "authorized = 1".
# * <tt>:order</tt> - specify the order in which the associated objects are returned as a "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:uniq</tt> - if set to true, duplicate associated objects will be ignored by accessors and query methods
# * <tt>:finder_sql</tt> - overwrite the default generated SQL used to fetch the association with a manual one
# * <tt>:delete_sql</tt> - overwrite the default generated SQL used to remove links between the associated
# classes with a manual one
# * <tt>:insert_sql</tt> - overwrite the default generated SQL used to add links between the associated classes
# with a manual one
#
# Option examples:
# has_and_belongs_to_many :projects
# has_and_belongs_to_many :nations, :class_name => "Country"
# has_and_belongs_to_many :categories, :join_table => "prods_cats"
def has_and_belongs_to_many(association_id, options = {})
validate_options([ :class_name, :table_name, :foreign_key, :association_foreign_key, :conditions,
:join_table, :finder_sql, :delete_sql, :insert_sql, :order, :uniq ], options.keys)
association_name, association_class_name, association_class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key])
require_association_class(association_class_name)
join_table = options[:join_table] ||
join_table_name(undecorated_table_name(self.to_s), undecorated_table_name(association_class_name))
define_method(association_name) do |*params|
force_reload = params.first unless params.empty?
association = instance_variable_get("@#{association_name}")
if association.nil?
association = HasAndBelongsToManyAssociation.new(self,
association_name, association_class_name,
association_class_primary_key_name, join_table, options)
instance_variable_set("@#{association_name}", association)
end
association.reload if force_reload
association
end
before_destroy_sql = "DELETE FROM #{join_table} WHERE #{association_class_primary_key_name} = \\\#{self.quoted_id}"
module_eval(%{before_destroy "self.connection.delete(%{#{before_destroy_sql}})"}) # "
# deprecated api
deprecated_collection_count_method(association_name)
deprecated_add_association_relation(association_name)
deprecated_remove_association_relation(association_name)
deprecated_has_collection_method(association_name)
end
# Loads the <tt>file_name</tt> if reload_associations is true or requires if it's false.
def require_association(file_name)
if !associations_loaded.include?(file_name)
associations_loaded << file_name
reload_associations ? silence_warnings { load("#{file_name}.rb") } : require(file_name)
end
end
# Resets the list of dependencies loaded (typically to be called by the end of a request), so when require_association is
# called for that dependency it'll be loaded anew.
def reset_associations_loaded
self.associations_loaded = []
end
# Reload all the associations that have already been loaded once.
def reload_associations_loaded
associations_loaded.each { |file_name| silence_warnings { load("#{file_name}.rb") } }
end
private
# Raises an exception if an invalid option has been specified to prevent misspellings from slipping through
def validate_options(valid_option_keys, supplied_option_keys)
unknown_option_keys = supplied_option_keys - valid_option_keys
raise(ActiveRecord::ActiveRecordError, "Unknown options: #{unknown_option_keys}") unless unknown_option_keys.empty?
end
def join_table_name(first_table_name, second_table_name)
if first_table_name < second_table_name
join_table = "#{first_table_name}_#{second_table_name}"
else
join_table = "#{second_table_name}_#{first_table_name}"
end
table_name_prefix + join_table + table_name_suffix
end
def associate_identification(association_id, association_class_name, foreign_key, plural = true)
if association_class_name !~ /::/
association_class_name = type_name_with_module(
association_class_name ||
Inflector.camelize(plural ? Inflector.singularize(association_id.id2name) : association_id.id2name)
)
end
primary_key_name = foreign_key || Inflector.underscore(Inflector.demodulize(name)) + "_id"
return association_id.id2name, association_class_name, primary_key_name
end
def association_comparison_method(association_name, association_class_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{association_name}?(comparison_object, force_reload = false)
if comparison_object.kind_of?(#{association_class_name})
#{association_name}(force_reload) == comparison_object
else
raise "Comparison object is a #{association_class_name}, should have been \#{comparison_object.class.name}"
end
end
end_eval
end
def association_reader_method(association_name, association_finder)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{association_name}(force_reload = false)
if @#{association_name}.nil? || force_reload
begin
@#{association_name} = #{association_finder}
rescue ActiveRecord::StatementInvalid, ActiveRecord::RecordNotFound
nil
end
end
return @#{association_name}
end
end_eval
end
def has_one_writer_method(association_name, association_class_name, class_primary_key_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{association_name}=(association)
if association.nil?
@#{association_name}.#{class_primary_key_name} = nil
@#{association_name}.save(false)
@#{association_name} = nil
else
raise ActiveRecord::AssociationTypeMismatch unless #{association_class_name} === association
association.#{class_primary_key_name} = id
association.save(false)
@#{association_name} = association
end
end
end_eval
end
def belongs_to_writer_method(association_name, association_class_name, association_class_primary_key_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{association_name}=(association)
if association.nil?
@#{association_name} = self.#{association_class_primary_key_name} = nil
else
raise ActiveRecord::AssociationTypeMismatch unless #{association_class_name} === association
@#{association_name} = association
self.#{association_class_primary_key_name} = association.id
end
end
end_eval
end
def has_association_method(association_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def has_#{association_name}?(force_reload = false)
!#{association_name}(force_reload).nil?
end
end_eval
end
def build_method(method_prefix, collection_name, collection_class_name, class_primary_key_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{method_prefix + collection_name}(attributes = {})
association = #{collection_class_name}.new
association.attributes = attributes.merge({ "#{class_primary_key_name}" => id})
association
end
end_eval
end
def create_method(method_prefix, collection_name, collection_class_name, class_primary_key_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{method_prefix + collection_name}(attributes = nil)
#{collection_class_name}.create((attributes || {}).merge({ "#{class_primary_key_name}" => id}))
end
end_eval
end
def require_association_class(class_name)
return unless class_name
begin
require_association(Inflector.underscore(class_name))
rescue LoadError
# Failed to load the associated class -- let's hope the developer is doing the requiring himself.
end
end
end
end
end
|