method

configure_dependency_for_has_many

v3.0.9 - Show latest stable - Class: ActiveRecord::Associations::ClassMethods

configure_dependency_for_has_many(reflection, extra_conditions = nil)

private

Creates before_destroy callback methods that nullify, delete or destroy has_many associated objects, according to the defined :dependent rule. If the association is marked as :dependent => :restrict, create a callback that prevents deleting entirely.

See HasManyAssociation#delete_records. Dependent associations delete children, otherwise foreign key is set to NULL. See HasManyAssociation#delete_records. Dependent associations delete children if the option is set to :destroy or :delete_all, set the foreign key to NULL if the option is set to :nullify, and do not touch the child records if the option is set to :restrict.

The extra_conditions parameter, which is not used within the main Active Record codebase, is meant to allow plugins to define extra finder conditions.

# File activerecord/lib/active_record/associations.rb, line 1600
        def configure_dependency_for_has_many(reflection, extra_conditions = nil)
          if reflection.options.include?(:dependent)
            case reflection.options[:dependent]
              when :destroy
                method_name = "has_many_dependent_destroy_for_#{reflection.name}".to_sym
                define_method(method_name) do
                  send(reflection.name).each do |o|
                    # No point in executing the counter update since we're going to destroy the parent anyway
                    counter_method = ('belongs_to_counter_cache_before_destroy_for_' + self.class.name.downcase).to_sym
                    if(o.respond_to? counter_method) then
                      class << o
                        self
                      end.send(:define_method, counter_method, Proc.new {})
                    end
                    o.destroy
                  end
                end
                before_destroy method_name
              when :delete_all
                before_destroy do |record|
                  self.class.send(:delete_all_has_many_dependencies,
                  record,
                  reflection.name,
                  reflection.klass,
                  reflection.dependent_conditions(record, self.class, extra_conditions))
                end
              when :nullify
                before_destroy do |record|
                  self.class.send(:nullify_has_many_dependencies,
                  record,
                  reflection.name,
                  reflection.klass,
                  reflection.primary_key_name,
                  reflection.dependent_conditions(record, self.class, extra_conditions))
                end
              when :restrict
                method_name = "has_many_dependent_restrict_for_#{reflection.name}".to_sym
                define_method(method_name) do
                  unless send(reflection.name).empty?
                    raise DeleteRestrictionError.new(reflection)
                  end
                end
                before_destroy method_name
              else
                raise ArgumentError, "The :dependent option expects either :destroy, :delete_all, :nullify or :restrict (#{reflection.options[:dependent].inspect})"
            end
          end
        end

configure_dependency_for_has_many

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