Rails has_many關聯返回空數組

Question

訪問與用戶關聯的查詢不返回查詢列表，而是返回空白數組。

例如：

user = User.first 
    => [valid user] 
    i = Inquiry.first 
    => [valid inquiry] 
    i.user = user 
    user.inquiries 
    => #<ActiveRecord::Associations::CollectionProxy []> 

我的三個型號：

user.rb

class User < ActiveRecord::Base 
    devise :database_authenticatable, :registerable, 
     :recoverable, :rememberable, :trackable, :validatable 

    has_many :clients 
    has_many :inquiries 
end 

client.rb

class Client < ActiveRecord::Base 
    belongs_to :user 

    validates :user_id, :name, presence: true 
end 

inquiry.rb

class Inquiry < ActiveRecord::Base 
    belongs_to :user 

    validates :user_id, :client_name, presence: true 
end 

客戶端和查詢模型在遷移文件中有t.references，index：true。

Answer 1

由於您只是在控制檯上進行試驗，請嘗試如下所示

user = User.first 
user.inquiries.create(whatever the params are for inquiry) 

user.inquiries # will return the inquiries, which for now is just the one in an array. 

退房http://guides.rubyonrails.org/association_basics.html#has-many-association-reference更多信息

Answer 2

如果您使用:inverse_of方法來幫助導出一些內容，可以實現您想要的功能。所以像這樣定義的相關項目：

class User < ActiveRecord::Base 
    has_many :inquiries, inverse_of: :user 
end 

class Inquiry < ActiveRecord::Base 
    belongs_to :user, inverse_of: :inquiries 
end 

你會發現，在:inverse_of選項一起使用的值等於關聯的模型的關聯名。這樣，導軌知道檢查逆模型的關係，應該允許正是這一點：

u = User.first 
i = Inquiry.first 
i.user = u 
u.inquiries # => [i] 

欲瞭解更多的:inverse_of選項，搜索以下鏈接爲inverse_of：

1. http://apidock.com/rails/ActiveRecord/Associations/ClassMethods/belongs_to
2. http://apidock.com/rails/ActiveRecord/Associations/ClassMethods/has_many