从 has_many 获取列表关联 :through with a nested has_many in rails

Question

简单的问题我想不通。

如何获取与另一类型项目列表关联的关联项目列表。例如 Clinician has_many patients 到 care_group_assignments 和 patients has_many assessments。我想要一个 patients 的列表给我一个他们所有 assessments 的列表。 @patients 给我 patients 的列表；我如何获得他们的 assessments 列表？我希望 @assessments 成为与给定 clinician.

关联的所有 patients 关联的所有 assessments 的列表

我在 'Clinician' 和 'Patient' 之间有一个 has_many :through 关系，并且有一个联合模型 'CareGroupAssignment'。

clinician.rb（简体）

class Clinician < ActiveRecord::Base
    has_many :patients ,:through=> :care_group_assignments
    has_many :care_group_assignments, :dependent => :destroy
    has_many :assessments, :through => :patients

    belongs_to :user
    accepts_nested_attributes_for :user,  :allow_destroy => true
end

patient.rb

class Patient < ActiveRecord::Base
    has_many :clinicians ,:through=> :care_group_assignments
    has_many :care_group_assignments

    has_many :assessments, dependent: :destroy

    belongs_to :user
    accepts_nested_attributes_for :user,  :allow_destroy => true
end

care_group_assignments.rb

class CareGroupAssignment < ActiveRecord::Base
    belongs_to :clinician
    belongs_to :patient
end

我尝试使用 4720492, 9408931, and 15256541 的答案。

我正在尝试获取 ClinicianController 中的列表：

def show
  @clinician = Clinician.find_by(id: params["id"])
  @patients = @clinician.patients
  @assessments = @patients.assessments.order("created_at desc")
end

current_clinician 在我的 ApplicationController 中定义为：

class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception

  helper_method :current_user
  before_action :require_user
  helper_method :current_clinician
  before_action :require_clinician

  def current_user
    @current_user ||= User.find_by!(auth_token: cookies[:auth_token]) if cookies[:auth_token]
  end

  def require_user
    if current_user.nil?
      redirect_to new_session_path
    end
  end

  def current_clinician
    current_user.clinician
  end

  def require_clinician
    if current_clinician.nil?
      redirect_to new_session_path
    end
  end
end

现在我得到一个 NoMethodError in CliniciansController#show,

undefined method `assessments' for #Patient:.....

Rails 4.1.8，ruby 2.2.1p85，PostgreSQL

谢谢

Answer 1

根据您的 Patient 模型，Patient has_many 评估，但实际上 show 您使用：

@assessments = @patients.assessments.order("created_at desc")

其中 @patients - 模型的项目列表 Patient。

你应该在那里重构你的逻辑。

Answer 2

尝试这样做：

 @assessments = Assessment.joins(:patient => {:care_group_assignments => :clinician).where(["clinicians.id = ?", @clinician.id]).order("assessments.created_at desc")

希望对你有所帮助。

Answer 3

你试过@clinician.assessments了吗？通过 AR 和 join tables 的魔力，你应该能够得到你想要的结果！

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