什么是belongs_to的和HAS_ONE之间的区别？ [英] What's the difference between belongs_to and has_one?

问题描述

之间的区别是什么 belongs_to的和 HAS_ONE ？

读Ruby on Rails的指南并没有帮助我。

Reading the Ruby on Rails guide hasn't helped me.

推荐答案

他们基本上做同样的事情，唯一的区别是你的关系是什么边。如果用户有一个简介，然后在用户类，你就会有 HAS_ONE：简介和简介类，你不得不 belongs_to的：用户。要确定谁拥有其他对象，看看那里的外键。我们可以说，一个用户拥有一个简介，因为配置文件表中有一个 USER_ID 列。如果有一个名为 PROFILE_ID 在用户列表，但是，我们可以说，一个简介有一个用户和belongs_to的/ HAS_ONE位置将被交换。

They essentially do the same thing, the only difference is what side of the relationship you are on. If a User has a Profile, then in the User class you'd have has_one :profile and in the Profile class you'd have belongs_to :user. To determine who "has" the other object, look at where the foreign key is. We can say that a User "has" a Profile because the profiles table has a user_id column. If there was a column called profile_id on the users table, however, we would say that a Profile has a User, and the belongs_to/has_one locations would be swapped.

此处是一个更详细的解释。

here is a more detailed explanation.

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