回调函数在rails before_save中不起作用

I have the following in the model:

我在模型中有以下内容：

before_save :set_defaults

def set_defaults
  self.num_results ||= 5
end

And I create the object in my controller like this:

我在我的控制器中创建对象，如下所示：

Search.create!(  :keyword        => params[:keyword],
                 :ip_address     => request.remote_ip,
                 :referring_page => request.referer )

Even though I haven't set a value for num_results it's still getting saved as 0 (which is the default value in the DB schema). The callback function doesn't get called at all. Any clues?

即使我没有为num_results设置一个值，它仍然保存为0（这是数据库模式中的默认值）。根本没有调用回调函数。有什么线索吗？

Update:

更新：

I turns out the callback does get called, the problem is in:

我发现回调确实被调用，问题在于：

self.num_results ||= 5

self.num_results || = 5

How would I set the default value in ruby? As this doesn't seem to work.

我如何在ruby中设置默认值？因为这似乎不起作用。

1 个解决方案

#1

num_results is only set to 5, if num_result is nil. In your case it is set to 0 by default, so the assignemt does not do anything. Try to change your assignment to:

如果num_result为nil，则num_results仅设置为5。在您的情况下，默认设置为0，因此assignemt不执行任何操作。尝试将您的作业更改为：

self.num_results = 5