模块：Mongoid::Association::Referenced

定义于：

lib/mongoid/association/referenced/has_one.rb 、
lib/mongoid/association/referenced/has_many.rb、
lib/mongoid/association/referenced/syncable.rb、
lib/mongoid/association/referenced/auto_save.rb、
lib/ mongoid/association/referenced/belongs_to.rb,
lib/mongoid/association/referenced/counter_cache.rb,
lib/mongoid/association/referenced/has_one/eager.rb,
lib/mongoid/association/referenced/has_one/proxy.rb,
lib/mongoid/association/referenced/has_many/eager.rb,
lib/mongoid/association/referenced/has_many/proxy.rb,
lib/mongoid/association/referenced/has_one/bounding.rb,
lib/mongoid/association/referenced/ belongs_to/eager.rb,
lib/mongoid/association/referenced/belongs_to/proxy.rb,
lib/mongoid/association/referenced/has_many/bounding.rb,
lib/mongoid/association/referenced/has_one/buildable.rb,
lib/ mongoid/association/referenced/belongs_to/bounding.rb,
lib/mongoid/association/referenced/has_many/buildable.rb,
lib/mongoid/association/referenced/has_many/enumerable.rb,
lib/mongoid/association/referenced/ belongs_to/buildable.rb,
lib/mongoid/association/referenced/has_and_belongs_to_many.rb,
lib/mongoid/association/referenced/with_poly态_criteria.rb,
lib/mongoid/association/referenced/has_and_belongs_to_many/eager.rb,
lib/mongoid/association/ referenced/has_and_belongs_to_many/proxy.rb、lib/mongoid/association/referenced/has_and_belongs_to_many/bounding.rb、lib/mongoid/association/referenced/has_and_belongs_to_many/buildable.rb

在命名空间下定义

模块： AutoSave 、 CounterCache 、 Syncable 、 WithPolymorphicCriteria 类：BelongsTo 、 HasAndBelongsToMany 、 HasMany 、 HasOne