Question

我有以下带有关联的类：

class Customer < ActiveRecord::Base
  has_many :orders
  has_many :tickets, :through => :orders
  has_many :technicians, :through => :ticket
  has_many :services, :through => :ticket
end

class Order < ActiveRecord::Base
  belongs_to :customer
  has_many :tickets
  has_many :technicians, :through => :tickets
  has_many :services, :through => :tickets
end  

class Service < ActiveRecord::Base
  has_many :tickets
  has_many :technicians, :through => :tickets
  has_many :orders, :through => :tickets
end  

class Technician < ActiveRecord::Base
  has_many :tickets, :order => 'created_at DESC'
  has_many :services, :through => :tickets
  has_many :orders, :through => :tickets
end  

class Ticket < ActiveRecord::Base
  belongs_to :technician
  belongs_to :service
  belongs_to :order
end

我能做到：
technician.tickets.service.price

但我做不到：
customer.orders.technician.name
customer.orders.last.tickets.technician.name

我如何从客户到技术人员或服务人员？

Answer 1

问题是你无法在一组对象上调用属性。

customer.orders.technician.name

这里有一个orders的集合。每个order可以有不同的technician。这就是为什么你不能在集合上调用technician。

解决方案：在每个technician对象上调用order：

customer.orders.each do |order|
  order.technician.name
end

第二个例子也是如此。而不是：

customer.orders.last.tickets.technician.name

使用：

customer.orders.last.tickets.each do |ticket|
  ticket.technician.name
end

Active Record Rails 3个关联无法正常工作

1 个答案: