method
through_reflection

through_reflection()
public
Returns the AssociationReflection object specified in the :through option of a HasManyThrough or HasOneThrough association. Example:
class Post < ActiveRecord::Base has_many :taggings has_many :tags, :through => :taggings end tags_reflection = Post.reflect_on_association(:tags) taggings_reflection = tags_reflection.through_reflection