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Class: ActiveRecord::Associations::SingularAssociation

Do not use. This class is for internal use only.
Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
BelongsToAssociation, BelongsToPolymorphicAssociation, HasOneAssociation, HasOneThroughAssociation
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Association
Instance Chain:
self, Association
Inherits: ActiveRecord::Associations::Association
Defined in: activerecord/lib/active_record/associations/singular_association.rb

Class Method Summary

Association - Inherited

.new

Instance Attribute Summary

Association - Inherited

#collection?

Whether the association represent a single record or a collection of records.
#disable_joins,
#loaded?

Has the target been already loaded?
#options, #owner, #reflection,
#stale_target?

The target is stale if the target no longer points to the record(s) that the relevant foreign_key(s) refers to.
#target,
#target=

Sets the target of this association to \target, and the loaded flag to true.
#find_target?,
#foreign_key_present?

Returns true if there is a foreign key present on the owner which references the target.
#violates_strict_loading?

Instance Method Summary

Association - Inherited

#async_load_target, #create, #create!, #extensions, #initialize_attributes, #inversed_from, #inversed_from_queries,
#klass

Returns the class of the target.
#load_target

Loads the target if needed and returns it.
#loaded!

Asserts the target has been loaded setting the loaded flag to true.
#marshal_dump

We can’t dump @reflection and @through_reflection since it contains the scope proc.
#marshal_load,
#reload

Reloads the target and returns self on success.
#remove_inverse_instance

Remove the inverse association, if possible.
#reset

Resets the loaded flag to false and sets the target to nil.
#reset_negative_cache, #reset_scope, #scope,
#set_inverse_instance

Set the inverse association, if possible.
#set_inverse_instance_from_queries, #set_strict_loading,
#association_scope

The scope for this association.
#build_record, #enqueue_destroy_association,
#ensure_klass_exists!

Reader and writer methods call this so that consistent errors are presented when the association target class does not exist.
#find_target,
#foreign_key_for?

Returns true if record contains the foreign_key.
#inversable?, #inverse_association_for,
#inverse_reflection_for

Can be redefined by subclasses, notably polymorphic belongs_to The record parameter is necessary to support polymorphic inverses as we must check for the association in the specific class of the record.
#invertible_for?

Returns true if inverse association on the given record needs to be set.
#matches_foreign_key?,
#raise_on_type_mismatch!

Raises ::ActiveRecord::AssociationTypeMismatch unless record is of the kind of the class of the associated objects.
#scope_for_create,
#skip_statement_cache?

Returns true if statement cache should be skipped on the association reader.
#skip_strict_loading,
#stale_state

This should be implemented to return the values of the relevant key(s) on the owner, so that when stale_state is different from the value stored on the last find_target, the target is stale.
#target_scope

Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e.

Constructor Details

This class inherits a constructor from ActiveRecord::Associations::Association

Instance Method Details

#_create_record(attributes, raise_error = false, &block) (private)

Raises:

[ GitHub ] 

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 67



def _create_record(attributes, raise_error = false, &block)
  record = build_record(attributes, &block)
  saved = record.save
  set_new_record(record)
  raise RecordInvalid.new(record) if !saved && raise_error
  record
end


  








  

    #build(attributes = nil, &block)  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 29



def build(attributes = nil, &block)
  record = build_record(attributes, &block)
  set_new_record(record)
  record
end


  








  

    #find_target(async: false)   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 47



def find_target(async: false)
  if disable_joins
    if async
      scope.load_async.then(&:first)
    else
      scope.first
    end
  else
    super.then(&:first)
  end
end


  








  

    #force_reload_reader  
  



  

    

Implements the reload reader method, e.g. foo.reload_bar for Foo.has_one :bar


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 37



def force_reload_reader
  reload(true)
  target
end


  








  

    #reader  
  



  

    

Implements the reader method, e.g. foo.bar for Foo.has_one :bar


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 7



def reader
  ensure_klass_exists!

  if !loaded? || stale_target?
    reload
  end

  target
end


  








  

    #replace(record)   (private)
  



  

    
  





  
Raises:


    
  
  • 
    (NotImplementedError)
  
    • 





  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 59



def replace(record)
  raise NotImplementedError, "Subclasses must implement a replace(record) method"
end


  








  

    #reset  
  



  

    

Resets the loaded flag to false and sets the target to nil.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 18



def reset
  super
  @target = nil
  @future_target = nil
end


  








  

    #scope_for_create   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 43



def scope_for_create
  super.except!(*Array(klass.primary_key))
end


  








  

    #set_new_record(record)   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 63



def set_new_record(record)
  replace(record)
end


  








  

    #writer(record)  
  



  

    

Implements the writer method, e.g. foo.bar= for Foo.belongs_to :bar


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/singular_association.rb', line 25



def writer(record)
  replace(record)
end