扶手：的has_many通过与多态关联 - 将这项工作？ [英] Rails: has_many through with polymorphic association - will this work?

问题描述

A 人可以有多个活动，每个事件可以有一个多态 Eventable 记录。如何指定关系的人和 Eventable 记录？

A Person can have many Events and each Event can have one polymorphic Eventable record. How do I specify the relationship between the Person and the Eventable record?

下面是我的模型：

class Event < ActiveRecord::Base
  belongs_to :person
  belongs_to :eventable, :polymorphic => true
end

class Meal < ActiveRecord::Base
  has_one :event, :as => eventable
end

class Workout < ActiveRecord::Base
  has_one :event, :as => eventable
end

主要的问题是关于人类：

class Person < ActiveRecord::Base
  has_many :events
  has_many :eventables, :through => :events  # is this correct???
end

我说的has_many：eventables，：通过=＆GT; ：？事件像我上面

还是我必须拼他们全力以赴，像这样：

Or do I have to spell them all out like so:

has_many :meals, :through => :events
has_many :workouts, :through => :events

如果你看到一个更简单的方式来完成我后，我所有的耳朵！ ： - ）

If you see an easier way to accomplish what I'm after, I'm all ears! :-)

推荐答案

您需要做的：

class Person < ActiveRecord::Base
  has_many :events
  has_many :meals, :through => :events, :source => :eventable,
    :source_type => "Meal"
  has_many :workouts, :through => :events, :source => :eventable,
    :source_type => "Workout"
end

这将使你能够做到这一点：

This will enable you to do this:

p = Person.find(1)

# get a person's meals
p.meals.each do |m|
  puts m
end

# get a person's workouts
p.workouts.each do |w|
  puts w
end

# get all types of events for the person
p.events.each do |e|
  puts e.eventable
end

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