Module: ActiveRecord::Reflection::ClassMethods
Relationships & Source Files | |
Defined in: | activerecord/lib/active_record/reflection.rb |
Overview
Reflection enables the ability to examine the associations and aggregations of Active Record classes and objects. This information, for example, can be used in a form builder that takes an Active Record object and creates input fields for all of the attributes depending on their type and displays the associations to other objects.
MacroReflection
class has info for AggregateReflection
and AssociationReflection
classes.
Instance Method Summary
-
#reflect_on_aggregation(aggregation)
Returns the
AggregateReflection
object for the namedaggregation
(use the symbol). -
#reflect_on_all_aggregations
Returns an array of
AggregateReflection
objects for all the aggregations in the class. -
#reflect_on_all_associations(macro = nil)
Returns an array of
AssociationReflection
objects for all the associations in the class. -
#reflect_on_all_autosave_associations
Returns an array of
AssociationReflection
objects for all associations which have:autosave
enabled. -
#reflect_on_association(association)
Returns the
AssociationReflection
object for theassociation
(use the symbol). -
#reflections
Returns a
::Hash
of name of the reflection as the key and anAssociationReflection
as the value.
Instance Method Details
#reflect_on_aggregation(aggregation)
Returns the AggregateReflection
object for the named aggregation
(use the symbol).
Account.reflect_on_aggregation(:balance) # => the balance AggregateReflection
# File 'activerecord/lib/active_record/reflection.rb', line 69
def reflect_on_aggregation(aggregation) aggregate_reflections[aggregation.to_s] end
#reflect_on_all_aggregations
Returns an array of AggregateReflection
objects for all the aggregations in the class.
# File 'activerecord/lib/active_record/reflection.rb', line 61
def reflect_on_all_aggregations aggregate_reflections.values end
#reflect_on_all_associations(macro = nil)
Returns an array of AssociationReflection
objects for all the associations in the class. If you only want to reflect on a certain association type, pass in the symbol (:has_many
, :has_one
, :belongs_to
) as the first parameter.
Example:
Account.reflect_on_all_associations # returns an array of all associations
Account.reflect_on_all_associations(:has_many) # returns an array of all has_many associations
# File 'activerecord/lib/active_record/reflection.rb', line 106
def reflect_on_all_associations(macro = nil) association_reflections = reflections.values association_reflections.select! { |reflection| reflection.macro == macro } if macro association_reflections end
#reflect_on_all_autosave_associations
Returns an array of AssociationReflection
objects for all associations which have :autosave
enabled.
# File 'activerecord/lib/active_record/reflection.rb', line 126
def reflect_on_all_autosave_associations reflections.values.select { |reflection| reflection. [:autosave] } end
#reflect_on_association(association)
Returns the AssociationReflection
object for the association
(use the symbol).
Account.reflect_on_association(:owner) # returns the owner AssociationReflection
Invoice.reflect_on_association(:line_items).macro # returns :has_many
# File 'activerecord/lib/active_record/reflection.rb', line 117
def reflect_on_association(association) reflections[association.to_s] end
#reflections
Returns a ::Hash
of name of the reflection as the key and an AssociationReflection
as the value.
Account.reflections # => {"balance" => AggregateReflection}
# File 'activerecord/lib/active_record/reflection.rb', line 77
def reflections @__reflections ||= begin ref = {} _reflections.each do |name, reflection| parent_reflection = reflection.parent_reflection if parent_reflection parent_name = parent_reflection.name ref[parent_name.to_s] = parent_reflection else ref[name] = reflection end end ref end end