Rails - 如何在多对多关系中列出每个对象的对象？

Question

我有多个具有连接表的模型，我想在控制器中实现这些项目的列表。

Customer <- many -> Products
Products <- many -> Teams
Products <- many -> Documents

型号：

class Customer < ActiveRecord::Base
   has_many :cstprd_relations
   has_many :products, :through => :cstprd_relations
end

class Product < ActiveRecord::Base
  has_many :cstprd_relations
  has_many :customers, :through => :cstprd_relations

  has_many :teaprd_relations
  has_many :teams, :through => :teaprd_relations
end

class Team < ActiveRecord::Base
  has_many :teaprd_relations
  has_many :products, :through => :teaprd_relations
end

class Document < ActiveRecord::Base
  has_many :prddoc_relations
  has_many :products, :through => :prddoc_relations
end

例如，文档迁移：

class CreateDocuments < ActiveRecord::Migration
  def change
    create_table :documents do |t|
      t.string :name

      t.timestamps null: false
    end
  end
end

class AddDocumentRefToProducts < ActiveRecord::Migration
  def change
    add_reference :products, :document, index: true, foreign_key: true
  end
end

如何列出属于产品的唯一文档并将它们 link 给团队（文档）？

像这样：

客户 1：

“产品 'Calc' 的文档 'Testing phase 1' 已由团队完成 'QA, TestTeam, Dev'"
“产品 'Phone' 的文档 'Testing phase 2' 已由团队完成 'QA, TechSpec, MarketingTeam'"
"Document 'Install Guide' for product 'App' is finished by teams 'Dev, TechSpec'"

Answer 1

不确定我是否理解这个问题，但您可以将 ActiveRecord 关联与 where 子句混合匹配，如下所示：

team_4_documents = Document.where(product_id: Team.find(4).products).all

( .find(4) 这里是一个让 Team 成为特定 Team 的例子)

Answer 2

也许这段代码展示了它的样子。

Product.all.each do | prod |
  Document.products( prod.id ).teams.each do | team |
    # generate message
  end 
end

或基于文档

Document.where( :id => id ).each do | doc |
  doc.products.each do | prod |
    prod.teams.each do | team |
      # generate you message
    end
  end
end

编辑在评论中回答问题

Customer.all.each do | cust |
  puts "Customer #{cust.name}"
  cust.products.each do | prod |
    prod.documents.each do | doc |
      print "* Document #{doc.name} for product #{prod.name} is finished by teams "
      puts "'" + prod.teams.map(&:name).join(', ') + "'"
    end 
  end
end

Rails - 如何在多对多关系中列出每个对象的对象？

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