Rails双重多态依赖：销毁没有正确销毁

Question

我有这个模型，LeaveManagementRule。 A Rule有sender，receiver。发送者可以是一个Role或User（同样为接收器）：

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 

这里是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模型是相同的用户模型。为了这个问题的目的，我不觉得需要详细说明。

这里是leave_management_rules表的数据库的摘录：

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 | 
+----+-----------+-------------+--------+-------------+---------------+------------+ 

我们将专注于user_id: 56，它出现在两个项目在这里（作为sender入境1，作为receiver为条目2）。现在

，我试图删除用户56我的Rails控制台：

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，现在是空的。但还有一个条目：

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 | 
+----+-----------+-------------+--------+-------------+---------------+------------+ 

有没有什么我在做我的代码错了？

我正在Rails 4.2.4

Answer 1

我没有找到答案，为什么dependent: :destroy回调不能正确触发。

相反，我写了一个自定义的before_destroy回调的User和Role型号：

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

我认为你没有做很好的double-polimymorphic关联。尝试这样的事情：

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