Rails 中通过同一个表进行多个 has_many 关联

发布于 2024-09-13 07:30:55 字数 680 浏览 8 评论 0 原文

我有以下数据库架构：

我希望能够做这样的事情：

dog.head << Feature.new(...)
dog.tail << Feature.new(...)

我是 Rails 新手，所以我并不总是 100% 确定我在写什么，但我尝试遵循 Dog 类的声明，但失败了:)：

class Dog < ActiveRecord::Base
  has_many :features, :through=>:dog_features
  has_many :head_features, :through=>:dog_features, :class_name=>'Feature', :conditions=>{:group=>1}
  has_many :tail_features, :through=>:dog_features, :class_name=>'Feature', :conditions=>{:group=>2}
end

原文

I have following database schema:

I want to be able to do something like this:

dog.head << Feature.new(...)
dog.tail << Feature.new(...)

I am new to Rails, so I am not always sure by 100% what I am writing, but I tried following declaration of Dog class, and failed :) :

class Dog < ActiveRecord::Base
  has_many :features, :through=>:dog_features
  has_many :head_features, :through=>:dog_features, :class_name=>'Feature', :conditions=>{:group=>1}
  has_many :tail_features, :through=>:dog_features, :class_name=>'Feature', :conditions=>{:group=>2}
end

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