Module: Sequel::Plugins::Polymorphic::ClassMethods

Defined in:
lib/sequel_polymorphic/sequel_polymorphic.rb

Instance Method Summary collapse

Instance Method Details

#many_to_many(*args, &block) ⇒ Object

Creates a many-to-many relationship. NB: Removing/clearing the collection deletes the instances in the through relationship (as opposed to nullifying the *able fields as in the one-to-many) Example: Post.many_to_many :tags, :through => :taggings, :as => :taggable



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# File 'lib/sequel_polymorphic/sequel_polymorphic.rb', line 90

def many_to_many(*args, &block)
  collection_name, options = *args
  options ||= {}

  if through = (options[:through] || options[:join_table]) and able = options[:as]
    able_id                = :"#{able}_id"
    able_type              = :"#{able}_type"
    collection_singular    = singularize(collection_name.to_s).to_sym # => tag
    collection_singular_id = :"#{collection_singular}_id"
    through_klass          = constantize(singularize(through.to_s).capitalize) # => Tagging

    associate(:many_to_many, collection_name,
      :left_key   => able_id,
      :join_table => through,
      :conditions => {able_type => self.to_s},
      :adder      => proc { |many_of_instance| through_klass.create(collection_singular_id => many_of_instance.pk, able_id => pk, able_type => self.class.to_s) },
      :remover    => proc { |many_of_instance| through_klass.where(collection_singular_id => many_of_instance.pk, able_id => pk, able_type => self.class.to_s).delete },
      :clearer    => proc { through_klass.where(able_id => pk, able_type => self.class.to_s).delete }
    )

  else
    associate(:many_to_many, *args, &block)
  end
end

#many_to_one(*args, &block) ⇒ Object Also known as: belongs_to

Example: Comment.many_to_one :commentable, polymorphic: true



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# File 'lib/sequel_polymorphic/sequel_polymorphic.rb', line 15

def many_to_one(*args, &block)
  able, options = *args
  options ||= {}

  if options[:polymorphic]
    model = self.to_s.downcase          # comment
    plural_model = pluralize(model)     # comments

    associate(:many_to_one, able,
      :reciprocal => plural_model.to_sym,
      :reciprocal_type => :many_to_one,
      :setter => (proc do |able_instance|
        self[:"#{able}_id"]   = (able_instance.pk if able_instance)
        self[:"#{able}_type"] = (able_instance.class.name if able_instance)
      end),
      :dataset => (proc do
        klass = constantize(send(:"#{able}_type"))
        klass.where(klass.primary_key => send(:"#{able}_id"))
      end),
      :eager_loader => (proc do |eo|
        id_map = {}
        eo[:rows].each do |model|
          model.associations[able] = nil
          ((id_map[model.send(:"#{able}_type")] ||= {})[model.send(:"#{able}_id")] ||= []) << model
        end
        id_map.each do |klass_name, id_map|
          klass = constantize(klass_name)
          klass.where(klass.primary_key=>id_map.keys).all do |related_obj|
            id_map[related_obj.pk].each do |model|
              model.associations[able] = related_obj
            end
          end
        end
      end)
    )

  else
    associate(:many_to_one, *args, &block)
  end
end

#one_to_many(*args, &block) ⇒ Object Also known as: has_many

Creates a one-to-many relationship. NB: Removing/clearing nullifies the *able fields in the related objects Example: Post.one_to_many :comments, as: :commentable



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# File 'lib/sequel_polymorphic/sequel_polymorphic.rb', line 61

def one_to_many(*args, &block)
  collection_name, options = *args
  options ||= {}

  if able = options[:as]
    able_id           = :"#{able}_id"
    able_type         = :"#{able}_type"
    many_dataset_name = :"#{collection_name}_dataset"

    associate(:one_to_many, collection_name,
      :key        => able_id,
      :reciprocal => able,
      :reciprocal_type => :one_to_many,
      :conditions => {able_type => self.to_s},
      :adder      => proc { |many_of_instance| many_of_instance.update(able_id => pk, able_type => self.class.to_s) },
      :remover    => proc { |many_of_instance| many_of_instance.update(able_id => nil, able_type => nil) },
      :clearer    => proc { send(many_dataset_name).update(able_id => nil, able_type => nil) }
    )

  else
    associate(:one_to_many, *args, &block)
  end
end