MongoMapper 一个模型上的两个一对多关系

Question

我正在尝试对类似于 StackOverflow 的问答系统进行建模，因为有一个问题，它有答案，并且问题和答案都属于不同的用户（但答案也属于问题）我的代码如下：

class User
    include MongoMapper::Document

    many :questions

    timestamps!
end

class Question
    include MongoMapper::Document

    belongs_to :user

    many :answers
    many :comments

    timestamps!
end

class Answer
    include MongoMapper::Document

    belongs_to :question

    many :comments

    timestamps!
end

我有几个问题：

1. 如何让两个事物与一个模型有关系？一个问题可以有多个答案，一个用户可以有多个答案。
2. 如果我使用question.answers.create() 创建答案，我如何将用户与其关联？我可以手动设置user_id 或类似的东西吗？

Answer 1

我自己想通了——我不太明白是什么让我相信我不能只拥有多重关系。我是多么封闭！

对于其他陷入困境的人：

class User
    include MongoMapper::Document

    many :questions
    many :answers

    timestamps!
end

class Question
    include MongoMapper::Document

    belongs_to :user

    many :answers
    many :comments

    timestamps!
end

class Answer
    include MongoMapper::Document

    belongs_to :question
    belongs_to :user

    many :comments

    timestamps!
end

像这样创建新的“答案”：

q = Question.find(id)
u = User.find(id)
a = q.answers.create(
    :user_id => u._id
)