Rails has_many：through - >如何設置關聯以從多個連接模型中拉取？

Question

我想設置多個has_many：通過並行關係。這裏是我的2個標準和2個連接模型：

User.rb

has_many :ownerships, dependent: :destroy 
has_many :devices, through: :ownerships 

has_many :bookings, dependent: :destroy 
has_many :devices, through: :bookings 

Ownership.rb

belongs_to :user, touch: true, counter_cache: :devices_count 
belongs_to :device, touch: true 

Booking.rb

belongs_to :user, touch: true, counter_cache: :bookings_count 
belongs_to :device, touch: true, counter_cache: :bookings_count 

Device.rb

has_many :ownerships, dependent: :destroy 
has_many :users, through: :ownerships 

has_many :bookings, dependent: :destroy 
has_many :users, through: :bookings 

預期該電流設置不工作，似乎是加盟模式之間的串擾。我希望連接模型能夠獨立並行（即用戶可以擁有關係 - 所有權 - 設備無法預訂）。我不在這裏尋找嵌套的has_many：through關係。

當我更改設備的用戶所有權似乎改變了預訂的數量，反之亦然......我應該如何正確設置它的任何想法？

Answer 1

我想你已經得到了第一個錯誤是你同名調用兩個協會（users/devices）

幫助任何進一步的受訪者中，真正的問題是 - >how do you set up an association to pull from multiple join models?

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快速修復

的Rails協會按其類爲主命名，但BEC衝突的使用，你應該避免設置它們兩次。這就是你看到當前問題的原因。一個簡單的分辨率會用不同的名字來調用關聯：

User.rb 
has_many :ownerships, dependent: :destroy 
has_many :owner_devices, through: :ownerships, class_name: "Device", foreign_key: "ownership_id" 

has_many :bookings, dependent: :destroy 
has_many :booking_devices, through: :ownerships, class_name: "Device", foreign_key: "booking_id" 

我仍然在尋找的信息，你怎麼可以設置關聯使用兩個模型

Answer 2

這似乎是一個可行的解決方案如下豐富佩克建議：

User.rb

has_many :ownerships, dependent: :destroy 
has_many :device_ownerships, through: :ownerships, class_name: "Device", foreign_key: "device_id", source: :device 

has_many :bookings, dependent: :destroy 
has_many :device_bookings, through: :bookings, class_name: "Device", foreign_key: "device_id", source: :device 

Booking.rb（加入模型）

belongs_to :user, touch: true, counter_cache: :bookings_count 
belongs_to :device, touch: true, counter_cache: :bookings_count 

Ownership.rb（加入模型）

belongs_to :user, touch: true, counter_cache: :devices_count 
belongs_to :device, touch: true, counter_cache: :users_count 

設備。RB

has_many :ownerships, dependent: :destroy 
has_many :user_ownerships, through: :ownerships, class_name: "User", foreign_key: "user_id", source: :user 

has_many :bookings, dependent: :destroy 
has_many :user_bookings, through: :bookings, class_name: "User", foreign_key: "user_id", source: :user 

說實話，我在爲什麼foreign_key的需要（？）被設置爲他們有點糊塗了，所以我必須做更多的閱讀了。否則它看起來是功能性的，我沒有看到這些連接模型之間的串擾了。