Question

有人可以帮我弄清楚我应该在change_default方法中输入什么代码吗？

我希望能够做到这样......

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>]

如您所见，更新已运行，但默认值未设置为false。如果您有任何我可以查看的建议或事项，请告诉我。

Answer 1

需要排除正在修改的当前记录。添加了where.not子句

  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

Answer 2

在示例中，您似乎永远不会在角色上调用save。因此，您的before_save :change_default未被执行。也许在role.save中添加def default!至少会执行before_save因为我不确定您当前的控制台测试是否实际运行change_default方法。

如果我错了并且它实际上正在运行，那么我不确定为什么你的块不会将default值设置为false。

Before_save =更改多对多的默认值

2 个答案: