使用值Friendly_id从belongs_to的关联 [英] Friendly_id using value from belongs_to association

问题描述

我有以下型号：

 类用户＆LT; ActiveRecord的::基地
  延长FriendlyId
  friendly_id：FIRST_NAME，：使用=＆GT; ：猛击  HAS_ONE：教授
  after_create：create_professor  高清create_professor
    self.professor ​​= Professor.create
  结束结束一流的教授，LT; ActiveRecord的::基地
  延长FriendlyId
  friendly_id：FIRST_NAME，：使用=＆GT; ：猛击  belongs_to的：用户
  高清FIRST_NAME
    user.first_name
  结束结束
 

在该 create_professor ​​调用;因此，执行传递到教授的模型（ self.professor ​​= Professor.create ），当它到达尝试这种方法来创建蛞蝓

 高清FIRST_NAME
  user.first_name
结束
 

我得到一个的零未定义的方法FIRST_NAME：NilClass ，如此看来教授对象不知道什么是自己的相关用户

如何解决这个任何提示？

解决方案

您不需要

 高清create_professor
    self.professor ​​= Professor.create
  结束
 

由于create_professor是由您的关联创建。<​​/ P>

I have the following models:

class User < ActiveRecord::Base
  extend FriendlyId
  friendly_id :first_name, :use => :slugged

  has_one :professor
  after_create :create_professor

  def create_professor
    self.professor = Professor.create 
  end

end 

class Professor < ActiveRecord::Base
  extend FriendlyId
  friendly_id :first_name, :use => :slugged

  belongs_to :user
  def first_name
    user.first_name 
  end

end

At the time that create_professor is called and therefore the execution passes to the Professor model (self.professor = Professor.create), when it gets to try to create the slug in this method:

def first_name
  user.first_name 
end

I get an undefined method first_name for nil:NilClass, so it seems the Professor object doesn't know what is his associated user.

Any tips on how to solve this?

解决方案

You don't need:

  def create_professor
    self.professor = Professor.create 
  end

Since create_professor is created by your association.

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