ruby-on-rails – 重新分配ActiveRecord实例和相应的外键

发布时间：2020-12-17 02:00:07 所属栏目：百科来源：网络整理

导读：在Rails / ActiveReocrd中有一种方法可以将一个实例替换为另一个实例,以便解决所有关系/外键. 我可以想象这样的事情： //setupcustomer1 = Customer.find(1)customer2 = Customer.find(2)//this would be coolcustomer1.replace_with(customer2) 假设custome

在Rails / ActiveReocrd中有一种方法可以将一个实例替换为另一个实例,以便解决所有关系/外键.

我可以想象这样的事情：

//setup
customer1 = Customer.find(1)
customer2 = Customer.find(2)

//this would be cool
customer1.replace_with(customer2)

假设customer1配置错误并且有人已经离开并创建了customer2,而不知道customer1那么能够快速将所有内容设置为客户2会很好

所以,这也需要更新任何外键

用户belongs_to：客户
???网站belongs_to：客户

然后任何具有外键customer_id = 1的用户/网站将通过此’replace_with’方法自动设置为2

这样的事情存在吗？

[我可以想象一个涉及Customer.reflect_on_all_associations(：has_many)等的黑客攻击]

干杯,
?

解决方法

像这样的东西可以工作,虽然可能有更合适的方式：

更新：更正了关联示例中的一些错误.

class MyModel < ActiveRecord::Base

  ...

  # if needed,force logout / expire session in controller beforehand.
  def replace_with (another_record)
    # handles attributes and belongs_to associations
    attribute_hash = another_record.attributes
    attribute_hash.delete('id')
    self.update_attributes!(attribute_hash)

    ### Begin association example,not complete.

    # generic way of finding model constants
    find_model_proc = Proc.new{ |x| x.to_s.singularize.camelize.constantize }
    model_constant = find_model_proc.call(self.class.name)

    # handle :has_one,:has_many associations
    have_ones = model_constant.reflect_on_all_associations(:has_one).find_all{|i| !i.options.include?(:through)}
    have_manys = model_constant.reflect_on_all_associations(:has_many).find_all{|i| !i.options.include?(:through)}

    update_assoc_proc = Proc.new do |assoc,associated_record,id|
      primary_key = assoc.primary_key_name.to_sym
      attribs = associated_record.attributes
      attribs[primary_key] = self.id
      associated_record.update_attributes!(attribs)
    end

    have_ones.each do |assoc|
      associated_record = self.send(assoc.name)
      unless associated_record.nil?
        update_assoc_proc.call(assoc,self.id)
      end
    end

    have_manys.each do |assoc|
      associated_records = self.send(assoc.name)
      associated_records.each do |associated_record|
        update_assoc_proc.call(assoc,self.id)
      end
    end

    ### End association example,not complete.

    # and if desired..
    # do not call :destroy if you have any associations set with :dependents => :destroy
    another_record.destroy
  end

  ...

end

我已经列举了一个如何处理一些关联的例子,但总的来说这可能变得棘手.

（编辑：李大同）

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