Rails的 - 改变的关联不标记对象为脏 [英] Rails - Changing association doesn't mark object as dirty

问题描述

修改：添加澄清

由于以下两类

class Foo < ActiveRecord::Base
  belongs_to :bar
end

class Bar < ActiveRecord::Base
end

当我更改栏上富，我想办法看到，foo的实例已更改：

When I change a bar on a foo, I would like a way to see that the foo instance has changed:

foo = Foo.find(x)
foo.bar      # returns #<Bar id:1>
foo.bar = Bar.new
foo.changed? # returns false
foo.changes  # returns an empty hash

我不想设定bar_id为肮脏的（因为它并没有改变），这将是不错的有以下几种：

I don't want to set bar_id as dirty (because it hasn't changed) It would be nice to have the following:

foo.changed? # returns true
foo.changes  # returns {:bar => [#<Bar id: 1>, nil]}

有一个聪明的方法来破解这个到Rails？还有一个原因是，这不是Rails的一部分？

Is there a clever way to hack this into Rails? Is there a reason this is not part of Rails?

推荐答案

今天我面临同样的问题，并通过轨道源运行后，我发现了一个解决方法，应该做你脑子里想什么，如果我得到你的问题正确的做法。

I faced the same problem today and after running through the rails-source i found a workaround that should do what you had in mind, if i got your question the right way.

传送到您的例子中，code看起来应该是：

Transferred to your example the code should look like that:

class Foo < ActiveRecord::Base
  belongs_to :bar

  def info
    bar.info
  end

  def info=(val)
    @changed_attributes[:info] = self.info unless val == self.info
    self.time_entry.update_attributes! :info => val
  end
end

class Bar < ActiveRecord::Base
  attr_accessible :info
end

这种方式，你丹通话.changed？和的.changes在富类的对象。

This way you dan call .changed? and .changes on objects of the Foo-class.

希望这有助于即使答案来得有点晚：）

hope this helps even if the answer comes a bit late :)

亲切的问候 基督教

BTW。遗憾的英文不好。我的工作是尽可能在我的红宝石技能;）的

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