Question

在Rails / ActiveReocrd中有一种方法可以将一个实例替换为另一个实例，以便解析所有关系/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，有人已经离开并创建了customer2，不知道customer1，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：customer

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， Ĵ

Answer 1

这样的事情可能有用，虽然可能有更合适的方式：

已更新：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, associated_record, 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, associated_record, 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

我已经列举了一个关于如何处理某些关联的示例，但总的来说这可能会变得棘手。

重新分配ActiveRecord实例和相应的外键

1 个答案: