ruby-on-rails - Rails 变量第一次加载然后为零!

Question

我收到以下错误:

ActionView::TemplateError (You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.include?) on line #24 of app/views/index/index.html.erb:
21: <% @achievements.each do |achievement| %>
22:     <%= achievement.name %>
23:     <%= achievement.level %>
24:     by <%= achievement.user.username %><br/>
25: <% end %>

奇怪的是，第一次加载索引页面时没有任何问题。当我刷新时，出现上述错误。

Controller 看起来像这样:

class IndexController < ApplicationController
    def index
        @achievements = Achievement.find(:all)
    end
end

这与缓存有关吗？还是它使用了太多内存？如果是这样，我可以用另一种方式加载用户名吗？我糊涂了!

Answer 1

尝试通过在查找中添加“:include => :user”来预先加载用户:

class IndexController < ApplicationController
    def index
        @achievements = Achievement.find(:all, :include => :user)
    end
end