使用外键数组的ActiveRecord关系 [英] ActiveRecord relation using an array of foreign keys

问题描述

是否可能在树和分支之间建立关系，例如：

Is that possible to establish a relationship between Tree and Branch such as:

class Tree < ActiveRecord::Base
  has_many :branches
end

class Branch < ActiveRecord::Base
  belongs_to :tree
end

但是带有一系列存储在Tree中的外键 branch_ids ？我知道这与默认过程相反，但我想这样做（仅用于测试）。

But with an array of foreign keys branch_ids stored in Tree? I know it's the opposite of the default process, but I want to do so (just for testing).

非常感谢您的帮助。

推荐答案

正如利塔姆伯格提到的那样，这是一个错误的模式。因为您说的是仅用于测试，所以
如果分支ID将是一列用逗号分隔的值。您将无法建立亲戚关系。但是您可以创建这样的属性

As Lichtamberg mentioned it is a bad schema. Since you said "just for testing", if branch ids will be a column with comma separated values. You won't be able to establish a relatioship. But you can create an atribute like this

class Tree < ActiveRecord::Base
  def branches
      Branch.all(branch_ids.split(','))
  end
  def branches=(branches)
      branch_ids = branches.collect(&:id).join(',')
  end
end

但是不要这样做！！！

But don't do this!!!

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