Rails雙重多態依賴：銷燬沒有正確銷燬

Question

我有這個模型，LeaveManagementRule。 A Rule有sender，receiver。發送者可以是一個Role或User（同樣爲接收器）：

class LeaveManagementRule < ActiveRecord::Base 

    belongs_to :sender, polymorphic: true # Sender can be a Role or a User 
    belongs_to :receiver , polymorphic: true # receiver can be a Role or a User 
    ... 
end 

這裏是User模型：

class User < ActiveRecord::Base 
    has_many :leave_management_rules, as: :sender, dependent: :destroy 
    has_many :leave_management_rules, as: :receiver, dependent: :destroy 
    ... 
end 

的Role模型是相同的用戶模型。爲了這個問題的目的，我不覺得需要詳細說明。

這裏是leave_management_rules表的數據庫的摘錄：

mysql> select * from leave_management_rules; 
+----+-----------+-------------+--------+-------------+---------------+------------+ 
| id | sender_id | sender_type | action | receiver_id | receiver_type | project_id | 
+----+-----------+-------------+--------+-------------+---------------+------------+ 
| 1 |  56 | User  |  1 |   19 | Role   |   33 | 
| 2 |  146 | User  |  2 |   56 | User   |   33 | 
+----+-----------+-------------+--------+-------------+---------------+------------+ 

我們將專注於user_id: 56，它出現在兩個項目在這裏（作爲sender入境1，作爲receiver爲條目2）。現在

，我試圖刪除用戶56我的Rails控制檯：

irb(main):020:0> u = User.find(56) 
irb(main):021:0> u.destroy 

所以，我希望我的leave_management_rules表，現在是空的。但還有一個條目：

mysql> select * from leave_management_rules; 
+----+-----------+-------------+--------+-------------+---------------+------------+ 
| id | sender_id | sender_type | action | receiver_id | receiver_type | project_id | 
+----+-----------+-------------+--------+-------------+---------------+------------+ 
| 1 |  56 | User  |  1 |   19 | Role   |   33 | 
+----+-----------+-------------+--------+-------------+---------------+------------+ 

有沒有什麼我在做我的代碼錯了？

我正在Rails 4.2.4

Answer 1

我沒有找到答案，爲什麼dependent: :destroy回調不能正確觸發。

相反，我寫了一個自定義的before_destroy回調的User和Role型號：

before_destroy :destroy_leave_management_rules 

def destroy_leave_management_rules 
    as_sender = LeaveManagementRule.where(sender: self) 
    as_receiver = LeaveManagementRule.where(receiver: self) 
    as_sender.destroy_all 
    as_receiver.destroy_all 
end 

Answer 2

我認爲你沒有做很好的double-polimymorphic關聯。嘗試這樣的事情：

class UserRulesRelation < ActiveRecord::Base 
    belongs_to :origin, polymorphic: true 
    belongs_to :leave_management_rules, polymorphic: true 
end 

class User < ActiveRecord::Base 
    has_many :user_rules_relations, as: :origin, dependent: :destroy 

    has_many :sent, through: :user_rules_relations, source: :leave_management_rules, source_type: "User" 
    has_many :received, through: :user_rules_relations, source: :leave_management_rules, source_type: "LeaveManagementRule" 
end 

class LeaveManagementRule < ActiveRecord::Base 
    has_many :user_rules_relations, as: :origin, dependent: :destroy 

    has_many :sent, through: :user_rules_relations, source: :leave_management_rules, source_type: "User" 
    has_many :received, through: :user_rules_relations, source: :leave_management_rules, source_type: "LeaveManagementRule" 
end