ActiveRecord::Associations::CollectionProxy

Association proxies in Active Record are middlemen between the object that holds the association, known as the @owner, and the actual associated object, known as the @target. The kind of association any proxy is about is available in @reflection. That’s an instance of the class ActiveRecord::Reflection::AssociationReflection.

For example, given

class Blog < ActiveRecord::Base
  has_many :posts
end

blog = Blog.first

the association proxy in blog.posts has the object in blog as @owner, the collection of its posts as @target, and the @reflection object represents a :has_many macro.

This class delegates unknown methods to @target via method_missing.

The @target object is not loaded until needed. For example,

blog.posts.count

is computed directly through SQL and does not trigger by itself the instantiation of the actual post records.