Rails 2：has_many：通过验证？答案

【问题标题】：Rails 2: has_many :through validation?Rails 2：has_many：通过验证？
【发布时间】：2010-03-22 14:49:01
【问题描述】：

Rails 2.1.0（由于一些限制，目前无法升级）我正在努力实现这一目标。有什么提示吗？

一个项目通过join模型有很多用户
一个用户通过join模型拥有多个项目
Admin 类继承 User 类。它还有一些特定于管理员的东西。
对于 Supervisor 和 Operator 类似 Admin 的继承
项目有一名管理员、一名主管和多名操作员。

现在我想 1. 在一个项目表单中提交项目、管理员、主管和操作员的数据 2. 验证所有并在项目表单上显示错误。

Project has_many :projects_users ; has_many :users, :through => :projects_users
User has_many :projects_users ; has_many :projects, :through => :projects_users
ProjectsUser = :id integer, :user_id :integer, :project_id :integer
ProjectUser belongs_to :project, belongs_to :user
Admin < User # User has 'type:string' column for STI
Supervisor < User
Operator < User

方法正确吗？欢迎提出任何建议。

【问题讨论】：

标签： ruby-on-rails orm has-many-through has-many-polymorphs

【解决方案1】：

我想单表 Inberitance 和嵌套表单可能会帮助您。您可能想在文档中阅读它。 http://api.rubyonrails.org/classes/ActiveRecord/Base.html

【讨论】：

我确实有用于单表继承的“类型”列。

【解决方案2】：

我发现答案在于使用 has_many 的单表继承：通过

class Project < ActiveRecord::Base
  has_many :projects_users, :dependent => :destroy
  has_many :users, :through => :projects_users, :dependent => :destroy
  has_one :admin, :through => :projects_users, :source => :user, :conditions => {:type => "Admin"}
  has_one :supervisor, :through => :projects_users, :source => :user, :conditions => {:type => "Supervisor"}
  has_many :operators, :through => :projects_users, :source => :user, :conditions => {:type => "Operator"}
  validates_presence_of :name
  validates_associated :admin

  def admin_attributes=(attributes)
    # build an admin object and apply to this relation
  end

  def supervisor_attributes=(attributes)
    # build a supervisor object and apply to this relation
  end

  def operator_attributes=(operator_attributes)
    operator_attributes.each do |attributes|
      # build an operator object for each set of attributes and apply to this relation
    end
  end
end

class User < ActiveRecord::Base
  has_many :projects_users, :dependent => :destroy
  has_many :projects, :through => :projects_users, :dependent => :destroy
  validates_presence_of :name
  validates_associated :projects
end

class ProjectsUser < ActiveRecord::Base
  belongs_to :project
  belongs_to :user
end

class Admin < User
end

class Supervisor < User
end

class Operator < User
end

现在我们可以拥有以下内容

project1.users # User objects for admin, supervisor and operators
project1.admin # User object for Admin
project1.supervisor # User object for Supervisor
project1.operators # User objects for Operator

包含所有这些的复杂形式可以有

<% form_for :project ...
    <% fields_for "project[admin_attributes]", @project.admin do |admin_form|
    ...
    <% @project.operators.each do |operator| %>
        <% fields_for "project[operator_attributes][]", operator do |operator_form| %>

等等……

【讨论】：

【解决方案3】：

我最终为管理员、主管和操作员使用了虚拟属性其他一切都通过 ORM 关联

【讨论】：