Question

我有这个型号：

class User < ActiveRecord::Base
  has_and_belongs_to_many :roles

  before_destroy do |u|
    if u.superadmin? and User.joins(:roles).where(:roles => {:superadmin => true}).count == 1
      u.errors.add(:base, "cannot delete last admin user")
      return false
    end
    return true
  end
end

class Role < ActiveRecord::Base
  has_and_belongs_to_many :users
end

当我尝试删除最后一个superadmin时，before_destroy回调会添加到errors数组并返回false。我在控制器中收到错误信息，一切似乎都没问题。

Rails3 从联接表中删除我的记录。的为什么？我返回false，因为我返回false，不继续删除。这是日志：

SQL (0.2ms)  SELECT COUNT(*) FROM "users" INNER JOIN "roles_users" ON "roles_users"."user_id" = "users"."id" INNER JOIN "roles" ON "roles"."id" = "roles_users"."role_id" WHERE "roles"."superadmin" = 't'
AREL (0.4ms)  DELETE FROM "roles_users" WHERE "roles_users"."user_id" = 1 AND "roles_users"."role_id" IN (1, 4)
Organization Load (0.4ms)  SELECT * FROM "organizations" INNER JOIN "organizations_users" ON "organizations".id = "organizations_users".organization_id WHERE ("organizations_users".user_id = 1 )

感谢您的帮助。

Answer 1

这看起来像这个rails错误，如果你使用旧的Rails版本（它应该在Rails 3.0.6 AFAIK中解决）：

https://rails.lighthouseapp.com/projects/8994/tickets/6191-habtm-association-is-being-destroyed-before-the-before_destory-callbacks-are-executed

当回调返回false时，Rails3删除HABTM记录

1 个答案: