同時Datamapper兩個協會

Question

可以說我有一個帖子，這篇文章應該有一定數量的評論，這些評論應該由certian用戶創建。因此，這些都是我的DataMapper模式：

class User 
include DataMapper::Resource 

property :id, Serial 
property :name, String, 
property :password, String 

has n, :post 
end 

class Post 
include DataMapper::Resource 

property :id, Serial 
property :text, Text 
property :created_at, DateTime 

belongs_to :user 
end 

class Comment 
include DataMapper::Resource 

property :text, Text, 
property :created_at, DateTime 

belongs_to :post 
belongs_to :user 
end 

所以我們可以說用戶X創建帖子和用戶Y想要創建這個信息的評論中。那我該怎麼做呢？我需要的是這樣的：

user = User.get(sessions[:user_id]) 
post = Post.get(params[:post_id]) 
comment = post.user.Comment.new { 
:text => "Bla", 
[...] 
} 

[...] 

comment.save 

[...] 

所以basicly模型後應與模型評論和型號後有關，我怎麼知道呢？

Answer 1

comment = Comment.create :post => post, :user => user, :text => 'Foo'