Rails“ ActiveRecord_Associations_CollectionProxy的未定义方法”； [英] Rails "undefined method for ActiveRecord_Associations_CollectionProxy"

问题描述

我有这个模型：

class Student < ActiveRecord::Base

    has_many :tickets
    has_many :movies, through: :tickets

end


class Movie < ActiveRecord::Base

    has_many :tickets, dependent: :destroy
    has_many :students, through: :tickets
    belongs_to :cinema

end


class Ticket < ActiveRecord::Base

    belongs_to :movie, counter_cache: true
    belongs_to :student

end


class Cinema < ActiveRecord::Base

    has_many :movies, dependent: :destroy
    has_many :students, through: :movies

    has_many :schools, dependent: :destroy
    has_many :companies, through: :yard_companies

end


class School < ActiveRecord::Base 

    belongs_to :company
    belongs_to :student
    belongs_to :cinema, counter_cache: true

end


class Teacher < ActiveRecord::Base

    belongs_to :movie, counter_cache: true
    belongs_to :company

end


class Contract < ActiveRecord::Base

    belongs_to :company
    belongs_to :student

end


class Company < ActiveRecord::Base

    has_many :teachers
    has_many :movies, through: :teachers

    has_many :contracts
    has_many :students, through: :contracts

end

如果我在 movies_controller.rb中写这个：

@students = @ movie.cinema.companies.students.all

我遇到此错误：

#Company :: ActiveRecord_Associations_CollectionProxy：0x00000007f13d88>的未定义方法学生>

相反，我这样写：

@students = @movie。 Cinema.companies.find（6）.students.all

它向我显示了我选择的学生中正确的学生。

it shows me the correct students in my select_collection.

如何更好地理解此过程？

更新：

我需要这部电影的电影公司的每个学生的全集。

I need the collection_select of every students in companies of a cinema of this movie.

如何

推荐答案

如 Nermin 您正在尝试从一组儿童中请求一组儿童。

As described by Nermin you're trying to request a collection of children, from a collection of children.

您可以使用 collect 沿以下路线收集公司的学生：

You could use collect to gather the students from the companies along the lines of:

@movie.cinema.companies.collect(&:students).flatten.uniq

但是我认为您最好按照以下方式为您的Student模型添加范围：

But I think you would do better to add a scope to your Student model along the lines of:

scope :for_companies, ->(_companies) {joins(:companies).where(company: _companies)}

用 Student.for_companies（@ movie.cinema.companies）

免责声明：未经测试，但应该作为起点！

Disclaimer: untested, but should be a starting point!

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