Question

我有这个模型，LeaveManagementRule。 Rule有一个sender，一个receiver。发件人可以是Role或User（对于收件人也是如此）：

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

以下是User型号：

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

Role模型与用户模型相同。出于这个问题的目的，我觉得不需要详细说明。

以下是db：{/ p>中leave_management_rules表的摘录

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

我们将重点关注user_id: 56，它出现在此处的两个条目中（作为条目1的sender，作为条目2的receiver。

现在，我正在尝试删除Rails控制台中的用户56：

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。但仍有一个条目：

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

我的代码中有什么问题吗？

我正在运行Rails 4.2.4

Answer 1

我认为你在double-polimymorphic协会做得不好。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

Answer 2

我没有找到为什么dependent: :destroy回调无法正确触发的答案。

相反，我为before_destroy和User模型编写了自定义Role回调：

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

Rails双重多态依赖：破坏未被正确破坏

2 个答案: