Rails的ActiveRecord的范围，它是＆QUOT;相反＆QUOT;另一范围，或者是用户的＆QUOT;缺少＆QUOT;一个属性 [英] Rails ActiveRecord Scope that is the "opposite" of another scope, or is users that "lack" a property

问题描述

我有一个模型，user.rb，我在其中定义管理​​员，这是一个有管理的通过权限表中角色的用户的作用域。

I have a model for user.rb, in which I define a scope for admins, which is users that have the role of admin through a permissions table.

has_many :permissions
has_many :roles, :through => :permissions

的范围是这样的：

The scope works like this:

scope :admins, joins(:permissions).merge(Permission.admin_permissions)

我也想创建一个名为范围非管理员之类的东西，这是不具有管理员角色的所有用户。

I'd also like to make a scope called non-admins or something like that, which is all users that do NOT have the admin role.

什么是做到这一点的最简单的方法是什么？

What's the easiest way to do this?

推荐答案

一个简单的方法，它的不会高性能对于很多用户的：

An easy way, which would not be performant for a lot of users:

admin_user_ids  = User.admins.map(&:id)
non_admin_users = User.all.reject { |u| admin_user_ids.include?(u.id) }

这篇关于Rails的ActiveRecord的范围，它是＆QUOT;相反＆QUOT;另一范围，或者是用户的＆QUOT;缺少＆QUOT;一个属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！