Before_save =多次更改默认值 [英] Before_save = Change default value for many to many

问题描述

有人可以帮我弄清楚应该在我的change_default方法中放什么代码吗?

Can someone help me figure out what code I should put in my change_default method?

我希望能够做这样的事情...

I would like to be able to do something like this...

user = User.find(1)
user.companies.first.default!
or 
user.companies.find_by_company_id(2).default!

我的代码:

class Role < ActiveRecord::Base 
  before_save :change_default

  belongs_to :user
  belongs_to :company

  def change_default
    #update default field for to false for current scope
    #Update current record default field to true

    #this is what I currently have, but it's not setting my defaults to false
    if self.default == true
     roles = Roles.where( :user_id => self.user_id) 
     roles.update_all(:default => false)
    end
  end

  def default!
    self.default=true
    self.save
  end

end

class User < ActiveRecord::Base
  has_many :roles
  has_many :companies, :through => :roles
end

class Company < ActiveRecord::Base
  has_many :roles
  has_many :users, :through => :roles
end

代码运行:

pry(main)> a.roles.last.default!

   (0.1ms)  begin transaction
SCOPING
  SQL (0.4ms)  UPDATE "roles" SET "default" = 'f' WHERE "roles"."user_id" = 1
   (2.0ms)  commit transaction
=> true

[5] pry(main)> a.roles

=> [#<Role id: 1, company_id: 1, name: nil, view_document: nil, edit_document: nil, upload_document: nil, delete_document: nil, review_document: nil, company_info: nil, company_clients: nil, company_users: nil, company_admin: nil, created_at: "2014-08-04 20:10:23", updated_at: "2014-08-04 22:29:40", user_id: 1, default: true>,

    #<Role id: 2, company_id: 2, name: nil, view_document: nil, edit_document: nil, upload_document: nil, delete_document: nil, review_document: nil, company_info: nil, company_clients: nil, company_users: nil, company_admin: nil, created_at: "2014-08-04 20:11:10", updated_at: "2014-08-04 20:11:10", user_id: 1, default: nil>,

    #<Role id: 3, company_id: 3, name: nil, view_document: nil, edit_document: nil, upload_document: nil, delete_document: nil, review_document: nil, company_info: nil, company_clients: nil, company_users: nil, company_admin: nil, created_at: "2014-08-04 20:11:14", updated_at: "2014-08-04 22:29:16", user_id: 1, default: true>]

您可以看到更新已运行，但是默认值未设置为false.如果您有任何建议或需要检查的内容，请告诉我.

As you can see the update ran, but the default values are not set to false. If you have any recommendations or things I can check, please let me know.

推荐答案

需要排除正在修改的当前记录.添加了where.not子句

Needed to exclude the current record that is being modified. Added the where.not clause

  def change_default
    if self.default_changed? && self.default == true
      roles = Role.where( :user_id => self.user_id)
      roles = roles.where.not(:id => self.id)
      roles.update_all(:default => false)  
    end
  end

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