Rails 中的双向图

发布于 2024-07-29 05:13:02 字数 573 浏览 7 评论 0原文

我有一个简单的模型“Match”，它应该保存两个对象（同类）之间的双向链接。

class Match < ActiveRecord::Base
  belongs_to :obj1, :class_name => "MyModel", :foreign_key => :obj1_id
  belongs_to :obj2, :class_name => "MyModel", :foreign_key => :obj2_id

...
end

我遇到的问题是，对于我发现的每个双向匹配，我都会得到两个数据库条目。例如 1：obj1-> 对象2, 2：obj2-> obj1

如何使用 validates_uniqueness_of 来避免这种情况？我尝试过

validates_uniqueness_of :obj1_id, :scope => :obj2_id
validates_uniqueness_of :obj2_id, :scope => :obj1_id

，但没有成功。

原文

I have a simple model "Match" that is supposed to save the bi-directional link between two objects (of the same kind).

class Match < ActiveRecord::Base
  belongs_to :obj1, :class_name => "MyModel", :foreign_key => :obj1_id
  belongs_to :obj2, :class_name => "MyModel", :foreign_key => :obj2_id

...
end

The problem I have is that for each bi-directional Match that I discover I get two database entries. E.g.
1: obj1 -> obj2,
2: obj2 -> obj1

How can I use validates_uniqueness_of to avoid this here? I tried

validates_uniqueness_of :obj1_id, :scope => :obj2_id
validates_uniqueness_of :obj2_id, :scope => :obj1_id

but that didn't work.

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べ映画 2024-08-05 05:13:02

validates_uniqueness_of :obj1_id, :scope => :obj2_id

def validate
  if find(:first, :conditions => { :obj1 => obj2, :obj2 => obj1 })
    errors.add_to_base("already exists")
  end
end

很难看。添加一些唯一的数据库索引。

validates_uniqueness_of :obj1_id, :scope => :obj2_id

def validate
  if find(:first, :conditions => { :obj1 => obj2, :obj2 => obj1 })
    errors.add_to_base("already exists")
  end
end

Pretty ugly. Add some unique database indexes.

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