问题描述
我有一个通过 has_many 关联到项目模型的任务模型,需要在通过关联删除/插入之前操作数据.
I have a Task model associated to a Project model via has_many through and need to manipulate the data before delete/insert via the association.
由于 "自动删除连接模型是直接的,不会触发销毁回调."我不能为此使用回调.
Since "Automatic deletion of join models is direct, no destroy callbacks are triggered." i can not use callbacks for this.
在任务中,我需要所有的 project_ids 来计算任务保存后的项目值.如何通过关联禁用删除或更改删除以在 has_many 上销毁?这个问题的最佳实践是什么?
In Task i need all project_ids to calculate a value for Project after Task is saved.How can i disable delete or change delete to destroy on has_many through association?What is best practise for this problem?
class Task
has_many :project_tasks
has_many :projects, :through => :project_tasks
class ProjectTask
belongs_to :project
belongs_to :task
class Project
has_many :project_tasks
has_many :tasks, :through => :project_tasks
推荐答案
似乎我必须使用 关联回调 before_add
、after_add
、before_remove
或 after_remove
Seems like i have to use associations callbacks before_add
, after_add
, before_remove
or after_remove
class Task
has_many :project_tasks
has_many :projects, :through => :project_tasks,
:before_remove => :my_before_remove,
:after_remove => :my_after_remove
protected
def my_before_remove(obj)
...
end
def my_after_remove(obj)
...
end
end
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