Class: ActiveRecord::Reflection::AssociationReflection

Inherits:
MacroReflection show all
Defined in:
activerecord/lib/active_record/reflection.rb

Overview

Holds all the meta-data about an association as it was specified in the Active Record class.

Direct Known Subclasses

ThroughReflection

Constant Summary collapse

VALID_AUTOMATIC_INVERSE_MACROS = 
[:has_many, :has_one, :belongs_to]
INVALID_AUTOMATIC_INVERSE_OPTIONS = 
[:conditions, :through, :polymorphic, :foreign_key]

Instance Attribute Summary collapse

Attributes inherited from MacroReflection

#active_record, #macro, #name, #options, #plural_name, #scope

Instance Method Summary collapse

Methods inherited from MacroReflection

#==, #autosave=, #class_name

Constructor Details

#initialize(macro, name, scope, options, active_record) ⇒ AssociationReflection

Returns a new instance of AssociationReflection.



227
228
229
230
231
232
233
234
 
# File 'activerecord/lib/active_record/reflection.rb', line 227

def initialize(macro, name, scope, options, active_record)
  super
  @collection = [:has_many, :has_and_belongs_to_many].include?(macro)
  @automatic_inverse_of = nil
  @type         = options[:as] && "#{options[:as]}_type"
  @foreign_type = options[:foreign_type] || "#{name}_type"
  @constructable = calculate_constructable(macro, options)
end

Instance Attribute Details

#foreign_type ⇒ Object (readonly)

Returns the value of attribute foreign_type



224
225
226
 
# File 'activerecord/lib/active_record/reflection.rb', line 224

def foreign_type
  @foreign_type
end

#parent_reflection ⇒ Object

:name, Reflection 


225
226
227
 
# File 'activerecord/lib/active_record/reflection.rb', line 225

def parent_reflection
  @parent_reflection
end

#type ⇒ Object (readonly)

Returns the value of attribute type



224
225
226
 
# File 'activerecord/lib/active_record/reflection.rb', line 224

def type
  @type
end

Instance Method Details

#active_record_primary_key ⇒ Object 



275
276
277
 
# File 'activerecord/lib/active_record/reflection.rb', line 275

def active_record_primary_key
  @active_record_primary_key ||= options[:primary_key] || primary_key(active_record)
end

#association_class ⇒ Object 



370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
 
# File 'activerecord/lib/active_record/reflection.rb', line 370

def association_class
  case macro
  when :belongs_to
    if options[:polymorphic]
      Associations::BelongsToPolymorphicAssociation
    else
      Associations::BelongsToAssociation
    end
  when :has_many
    if options[:through]
      Associations::HasManyThroughAssociation
    else
      Associations::HasManyAssociation
    end
  when :has_one
    if options[:through]
      Associations::HasOneThroughAssociation
    else
      Associations::HasOneAssociation
    end
  end
end

#association_foreign_key ⇒ Object 



266
267
268
 
# File 'activerecord/lib/active_record/reflection.rb', line 266

def association_foreign_key
  @association_foreign_key ||= options[:association_foreign_key] || class_name.foreign_key
end

#association_primary_key(klass = nil) ⇒ Object

klass option is necessary to support loading polymorphic associations



271
272
273
 
# File 'activerecord/lib/active_record/reflection.rb', line 271

def association_primary_key(klass = nil)
  options[:primary_key] || primary_key(klass || self.klass)
end

#belongs_to? ⇒ Boolean

Returns true if self is a belongs_to reflection.

Returns:

  • (Boolean) 


366
367
368
 
# File 'activerecord/lib/active_record/reflection.rb', line 366

def belongs_to?
  macro == :belongs_to
end

#build_association(attributes, &block) ⇒ Object

Returns a new, unsaved instance of the associated class. attributes will be passed to the class’s constructor.



238
239
240
 
# File 'activerecord/lib/active_record/reflection.rb', line 238

def build_association(attributes, &block)
  klass.new(attributes, &block)
end

#chain ⇒ Object

A chain of reflections from this one back to the owner. For more see the explanation in ThroughReflection.



309
310
311
 
# File 'activerecord/lib/active_record/reflection.rb', line 309

def chain
  [self]
end

#check_validity! ⇒ Object 



287
288
289
 
# File 'activerecord/lib/active_record/reflection.rb', line 287

def check_validity!
  check_validity_of_inverse!
end

#check_validity_of_inverse! ⇒ Object 



291
292
293
294
295
296
297
 
# File 'activerecord/lib/active_record/reflection.rb', line 291

def check_validity_of_inverse!
  unless options[:polymorphic]
    if has_inverse? && inverse_of.nil?
      raise InverseOfAssociationNotFoundError.new(self)
    end
  end
end

#collection? ⇒ Boolean

Returns whether or not this association reflection is for a collection association. Returns true if the macro is either has_many or has_and_belongs_to_many, false otherwise.

Returns:

  • (Boolean) 


348
349
350
 
# File 'activerecord/lib/active_record/reflection.rb', line 348

def collection?
  @collection
end

#constructable? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


242
243
244
 
# File 'activerecord/lib/active_record/reflection.rb', line 242

def constructable? # :nodoc:
  @constructable
end

#counter_cache_column ⇒ Object 



279
280
281
282
283
284
285
 
# File 'activerecord/lib/active_record/reflection.rb', line 279

def counter_cache_column
  if options[:counter_cache] == true
    "#{active_record.name.demodulize.underscore.pluralize}_count"
  elsif options[:counter_cache]
    options[:counter_cache].to_s
  end
end

#foreign_key ⇒ Object 



258
259
260
 
# File 'activerecord/lib/active_record/reflection.rb', line 258

def foreign_key
  @foreign_key ||= options[:foreign_key] || derive_foreign_key
end

#has_inverse? ⇒ Boolean

Returns:

  • (Boolean) 


325
326
327
 
# File 'activerecord/lib/active_record/reflection.rb', line 325

def has_inverse?
  inverse_name
end

#inverse_of ⇒ Object 



329
330
331
332
333
 
# File 'activerecord/lib/active_record/reflection.rb', line 329

def inverse_of
  return unless inverse_name

  @inverse_of ||= klass._reflect_on_association inverse_name
end

#join_table ⇒ Object 



254
255
256
 
# File 'activerecord/lib/active_record/reflection.rb', line 254

def join_table
  @join_table ||= options[:join_table] || derive_join_table
end

#klass ⇒ Object

Returns the target association’s class.

class Author < ActiveRecord::Base
  has_many :books
end

Author.reflect_on_association(:books).klass
# => Book

Note: Do not call klass.new or klass.create to instantiate a new association object. Use build_association or create_association instead. This allows plugins to hook into association object creation.



220
221
222
 
# File 'activerecord/lib/active_record/reflection.rb', line 220

def klass
  @klass ||= active_record.send(:compute_type, class_name)
end

#nested? ⇒ Boolean

Returns:

  • (Boolean) 


313
314
315
 
# File 'activerecord/lib/active_record/reflection.rb', line 313

def nested?
  false
end

#polymorphic? ⇒ Boolean

Returns:

  • (Boolean) 


393
394
395
 
# File 'activerecord/lib/active_record/reflection.rb', line 393

def polymorphic?
  options.key? :polymorphic
end

#polymorphic_inverse_of(associated_class) ⇒ Object 



335
336
337
338
339
340
341
342
343
 
# File 'activerecord/lib/active_record/reflection.rb', line 335

def polymorphic_inverse_of(associated_class)
  if has_inverse?
    if inverse_relationship = associated_class._reflect_on_association(options[:inverse_of])
      inverse_relationship
    else
      raise InverseOfAssociationNotFoundError.new(self, associated_class)
    end
  end
end

#primary_key_column ⇒ Object 



262
263
264
 
# File 'activerecord/lib/active_record/reflection.rb', line 262

def primary_key_column
  klass.columns_hash[klass.primary_key]
end

#quoted_table_name ⇒ Object 



250
251
252
 
# File 'activerecord/lib/active_record/reflection.rb', line 250

def quoted_table_name
  klass.quoted_table_name
end

#scope_chain ⇒ Object

An array of arrays of scopes. Each item in the outside array corresponds to a reflection in the #chain.



319
320
321
 
# File 'activerecord/lib/active_record/reflection.rb', line 319

def scope_chain
  scope ? [[scope]] : [[]]
end

#source_reflection ⇒ Object 



303
304
305
 
# File 'activerecord/lib/active_record/reflection.rb', line 303

def source_reflection
  self
end

#table_name ⇒ Object 



246
247
248
 
# File 'activerecord/lib/active_record/reflection.rb', line 246

def table_name
  klass.table_name
end

#through_reflection ⇒ Object 



299
300
301
 
# File 'activerecord/lib/active_record/reflection.rb', line 299

def through_reflection
  nil
end

#validate? ⇒ Boolean

Returns whether or not the association should be validated as part of the parent’s validation.

Unless you explicitly disable validation with validate: false, validation will take place when:

  • you explicitly enable validation; validate: true

  • you use autosave; autosave: true

  • the association is a has_many association

Returns:

  • (Boolean) 


361
362
363
 
# File 'activerecord/lib/active_record/reflection.rb', line 361

def validate?
  !options[:validate].nil? ? options[:validate] : (options[:autosave] == true || macro == :has_many)
end