Rails 4更新嵌套属性 [英] Rails 4 Update Nested Attributes

问题描述

更新嵌套属性追加而不是更新有很多关系
我正在尝试使用Rails 4 Update_attributes

Updating Nested Attributes append instead of updating in has many relationships I am trying to use Rails 4 Update_attributes

Class Person <ActiveRecord::Base
 has_many :pets
 accepts_nested_attributes_for :pets
end

Class Pet < ActiveRecord::Base
 belongs_to :person
end

在我的控制器中，我是将参数接收为
{id：23，house_no：'22A'，pets：[{name：'jeffy'，type：'dog'}，{name：'sharky'，type：'fish'}] }

In my controller I am recieveing the params as {id: 23, house_no:'22A', pets: [{name:'jeffy', type:'dog'}, {name:'sharky', type:'fish'}]}

，而我的更新方法是

def update
  @Person = Person.find(params[:id])
  if @Person.update(person_params)
    @Person.save
    render 'persons/create', status 200
  else
    render 'persons/create', status 400
  end
end

private
def person_params
  person_params = params.permit(:house_no)
  person_params.merge! ({pets_attributes: params[:pets]}) if params[:pets].present?
  person_params
end

现在，当我更新
时，如果这个人已经有一只宠物
，那么新的宠物会被附加，而不是更新
，例如，如果一个ID为1的人有1只宠物命名为 Tiger
，而我将该人更新为2只宠物命名为 Shasha和 Monti，则个人记录中有3只宠物（老虎，Shasha和Monti）而不是将其更新为2（Shasha和Monti）

Now when I update it and if the person already has a pet then the new pets gets appended instead of getting updated eg if a person with id 1 has 1 pet named "Tiger" and I update that person with 2 pets named "Shasha" and "Monti" then the person record has 3 pets (Tiger, Shasha and Monti) instead of updating it to 2 (Shasha and Monti)

推荐答案

请参见手册：

http://api.rubyonrails.org/v4.0.1/classes/ActiveRecord/NestedAttributes/ClassMethods.html

您需要发送诸如 pets_attributes之类的属性：[{name：'jeffy'，type：'dog'}，{name：'sharky '，键入：'fish'}]

，它应该可以正常工作。

and it should work fine.

请阅读

您不能w通过成员的属性哈希值设置或更新关联帖子的属性：包括键：posts_attributes并将帖子属性的哈希值数组作为值。对于每个没有id键的哈希值，将实例化一个新记录，除非哈希还包含一个评估为true的_destroy键。

You can now set or update attributes on the associated posts through an attribute hash for a member: include the key :posts_attributes with an array of hashes of post attributes as a value.For each hash that does not have an id key a new record will be instantiated, unless the hash also contains a _destroy key that evaluates to true.

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