Question

我有......

class Report < ActiveRecord::Base
  has_and_belongs_to_many :elements
end

class Element < ActiveRecord::Base
  has_and_belongs_to_many :reports
end

我在命令行看到一些非常奇怪的行为：

$Element.all
[#<Element id: 1, name: "fdafda", created_at: "2013-03-12 02:10:56", updated_at: "2013-03-12 02:10:56">,
 #<Element id: 2, name: "Foo", created_at: "2013-03-14 10:46:56", updated_at: "2013-03-14 10:46:56">, 
 #<Element id: 3, name: "Bar", created_at: "2013-03-14 10:47:03", updated_at: "2013-03-14 10:47:03">]

$ Report.first.elements
[#<Element id: 2, name: "Foo", created_at: "2013-03-14 10:46:56", updated_at: "2013-03-14 10:46:56">, 
 #<Element id: 2, name: "Foo", created_at: "2013-03-14 10:46:56", updated_at: "2013-03-14 10:46:56">, 
 #<Element id: 3, name: "Bar", created_at: "2013-03-14 10:47:03", updated_at: "2013-03-14 10:47:03">, 
 #<Element id: 3, name: "Bar", created_at: "2013-03-14 10:47:03", updated_at: "2013-03-14 10:47:03">]

(rdb:2) Report.first.elements.uniq
[#<Element id: 2, name: "Foo", created_at: "2013-03-14 10:46:56", updated_at: "2013-03-14 10:46:56">, 
 #<Element id: 3, name: "Bar", created_at: "2013-03-14 10:47:03", updated_at: "2013-03-14 10:47:03">]

Report.first.elements中的元素重复怎么可能？我怎么能阻止它？

rails -v
Rails 3.2.11
$ ruby -v
ruby 1.9.2p320 (2012-04-20 revision 35421) [x86_64-darwin12.2.1]

Answer 1

找到答案。在reports / id / elements / new的表单中有一个报表选择器。如果用户在报表选择器中选择了当前报表，则会在联接表中创建元素和报表之间的两个链接。

为什么ActiveRecord关联返回每个关联对象的两个副本

1 个答案: