Rails3 Active Admin-如何仅过滤满足集合中所有选中项目的记录 [英] Rails3 Active Admin - How to filter only records that meet all checked items in collection

问题描述

我与网络模型之间存在一对多的用户关联。我的架构信息的相关部分如下。

I have a one-to-many associaton of user to network model. The relevant parts of my schema information is as follows.

# == Schema Information      
# Table name: users
#
#  id                     :integer         not null, primary key
#  name                   :string(255)

#
# Table name: networks
#
#  id         :integer         not null, primary key
#  user_id    :integer
#  uid        :string(255)
#  name   :string(255)
#  pub_url    :string(255)

我想使用的name属性过滤出具有特定多个网络的用户网络模型。例如，如果我检查facebook和foursquare作为过滤器，我想找回同时连接了facebook和foursquare的用户。我当前的实现是传递一个包含用户可以添加的网络名称的数组，如下所示。

I want to filter out users who have specific multiple networks using the name property of the network model. For example if I check facebook and foursquare as filters, I want to get back users who have connected both facebook and foursquare. My current implementation is to pass an array containing the names of networks a user can add as displayed below.

filter :networks_name, :as => :check_boxes,
:collection => %w(facebook twitter foursquare linkedin)

但这对过滤器使用OR条件，以任何选中的项目。我真正想要得到的是满足所有已检查项目的用户。
实现此目标的正确方法是什么？

This however uses an OR condition for the filters which retrieves users with any of the checked items. What I actually want to get is users who meet all the checked items. What's the right way of achieving this?

推荐答案

ActiveAdmin使用meta_search作为其过滤器（ https://github.com/ernie/meta_search ）：

ActiveAdmin uses meta_search for its filters (https://github.com/ernie/meta_search):

filter :networks_name_all,
  :as => :check_boxes,
  :collection => %w(facebook twitter foursquare linkedin)

在您的用户模型中：

scope :networks_names_all_in, -> names {
  names.reduce(scoped) do |scope, name|
    subquery = User.select('`users`.`id`').
      joins(:networks).
      where('networks.name = ?', name)
    scope.where("`users`.`id` IN (#{subquery.to_sql})")
  end
}
search_methods :networks_name_all_in

这将为您创建一个不错的SQL查询，

This will create a nice single SQL query for you, with proper joins and where conditions.

例如：

User.networks_name_all_in(["facebook", "twitter"])

将生成以下SQL请求：

will generate the following SQL request:

SELECT *
FROM `users`
WHERE `users`.`id` IN (SELECT `users`.`id`
                       FROM `users`
                       INNER JOIN `networks`
                       ON `networks`.`user_id` = `users`.`id`
                       WHERE `networks`.`name` = 'facebook')
  AND `users`.`id` IN (SELECT `users`.`id`
                       FROM `users`
                       INNER JOIN `networks`
                       ON `networks`.`user_id` = `users`.`id`
                       WHERE `networks`.`name` = 'twitter')

更新：增加了功能范围。

更新2：使范围对范围合并问题具有弹性。

Update 2: Make scope resilient to scope merging problems.

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