Mongoid 3.1.0 CounterCache不起作用

本文介绍了Mongoid 3.1.0 CounterCache不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在尝试使用Mongoid CounterCache，但是它不起作用.

I'm trying to use Mongoid CounterCache but it doesn't work.

我尝试只使用

belongs_to :user, counter_cache: true

但是它返回

Problem: Invalid option :counter_cache provided to relation :user. Summary: Mongoid checks the options that are passed to the relation macros to ensure that no ill side effects occur by letting something slip by. Resolution: Valid options are: autobuild, autosave, dependent, foreign_key, index, polymorphic, touch, class_name, extend, inverse_class_name, inverse_of, name, relation, validate, make sure these are the ones you are using.

所以我加了

include Mongoid::CounterCache

重新启动我的网络服务器，然后再试一次，但它返回

Restarted my webserver then tried again, but it returns

uninitialized constant Mongoid::CounterCache

关于这个问题有什么想法吗?

Any ideas about this problem?

推荐答案

我遇到了同样的问题.这是对我有用的东西.

I ran into this same thing. Here's what worked for me.

假设您的应用程序中已经有这些类，然后您决定稍后添加counter_cache.因此，您将counter_cache: true添加到您的子类中

Let's say you have these class already in your app, and you decided to add the counter_cache later. So you add the counter_cache: true to your child class

class User include Mongoid::Document field :name, type: String has_many :things end class Thing include Mongoid::Document field :name, type: String belongs_to :user, counter_cache: true end

然后您跳入控制台并执行以下操作:

Then you hop into your console and do this:

u = User.first u.things.count #=> 10 u.things_count #=> NoMethodError: undefined method things_count User.update_counters(u.id, things_count: u.things.count) u.reload u.things_count #=> 10

如果任何人都可以通过更简单或更干净的方法来做到这一点，那就太棒了.

If anyone has an easier or cleaner way to do this, that would be awesome.