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如何与Rails 5中的has\u many through进行分组

activerecord postgresql ruby-on-rails

0

mayorsanmayor · 技术社区 · 7 年前

我有以下联想:

class Certificate < ApplicationRecord
  has_many :certificates_users
  has_many :users, :through => :certificates_users
end

class CertificatesUser < ApplicationRecord
  belongs_to :user
  belongs_to :certificate
end

class User < ApplicationRecord
  has_many :certificates_users, :dependent => :delete_all
  has_many :certificates, :through => :certificates_users
end

我正在尝试获取证书列表,然后按用户对其进行分组。基本上,列出所有用户并在其下显示其证书的子列表。下面是 UI looks like 只需点击桌子上的“市长”。

CertificatesUser 桌子

=> CertificatesUser(certificate_id: integer, user_id: integer, expiry_date: date, certificate_number: string, renewal_date: date, ispublic: integer)

answer ,我能够提出这些可能的解决方案,

Certificate.joins(:users).group('users.id').select('users.id')

User.joins(:certificates).group('certificates.id').select('certificates.id, certificates.name')

这里的问题是我需要的大部分字段都在 certificates_users certificates 桌子。

这是另一次尝试,试图让它工作,但没有工作- CertificatesUser.group(:user_id).select('user.id')

还有什么其他可能的解决办法?

3 回复 | 直到 7 年前

1

3

PGill 7 年前

@users = User.includes(certificates_users: [:certificate])

然后你可以在它们之间循环

@users.each do |u|
  u.certificates_users.each do |cu|
   cu.certificate_number
   cu.certificate.some_column
   ...
  end
end

仅获取具有证书的用户

@users = User.includes(certificates_users: [:certificate]).where("certificates_users.user_id = users.id")

2

0

Shiko 7 年前

根据您的模型中定义的关系,以下内容应适用:

CertificatesUser.joins(:user, :certificate)        
    .select('user_id, users.name, users.email, certificates.name')
    .group_by(&:user_id)

.group_by(&:user_id) 要根据json数组中的用户\ id对获取的数据进行分组,如下所示:

结果样本:

[1, [{ user_id: 1, certificate_id: 29, ....},{ user_id: 1, certificate_id: 22, ....}] ,
2, [{ user_id: 2, certificate_id: 34, ....},{ user_id: 2, certificate_id: 56, ....}] ,
3, [{ user_id: 3, certificate_id: 29, ....},{ user_id: 3, certificate_id: 12, ....}] ]

您可以从中添加字段用户证书但一定要用在而不是在 .

3

0

mayorsanmayor 7 年前

在控制器里,我有这个

@users_and_certificates = CertificatesUser.all.each_with_object({}) { |item, hash| hash[item.user_id] = item }

.card-body.table-responsive
  %table.table.table-hover.table-valign-middle
    %thead
      %tr
        %th Name
        %th E-mail
    %tbody
      - @users_and_certificates.each do |user_id, certificate_object|
         %tr{"data-target" => "#certificate_#{certificate_object.certificate_id}", "data-toggle" => "collapse"}
           - user = User.find(user_id)
           %td
             = user.full_name
           %td
             = user.email
         %tr
           %td.card-body.table-responsive.collapse{'id' => "certificate_#{certificate_object.certificate_id}"}
             %table.table.table-hover.table-valign-middle
               %thead
                 %tr
                   %th Certificate
                   %th Certificate No.
                   %th Expiry Date
                   %th Certificate
               %tbody
                 %tr
                   - certificate = Certificate.find(certificate_object.certificate_id)
                   %td
                     = certificate.name
                   %td
                     = certificate_object.certificate_number
                   %td
                     = certificate_object.expiry_date
                   %td Show

目前这个效果非常好。

谢谢。