Mongoid - 是否可以嵌入模型的embedded_in？

Question

是否有可能有以下的一种关系：

用户：

class User 
    include Mongoid::Document 
    include Mongoid::Paperclip 
    include Mongoid::Timestamps 

    store_in :users 
    belongs_to :team 
    field :full_name, :type => String 
    field :email,  :type => String 

    attr_accessible :full_name, 

end 

任务：

class Task 
    include Mongoid::Document 
    include Mongoid::Timestamps 

    embedded_in :user 
    embeds_one :sender, :class_name => "User" 

    field :text,  :type => String 
    field :due_time, :type => DateTime 
    field :completed, :type => Boolean, :default => false 

    attr_accessible :text, :due_time 
end 

但是当我尝试它在rails console，我有以下几点：

> u1 = User.where(...).first 
> u2 = User.where(...).first 
> task = Task.new 
> task.user = u1 
> task.sender = u2 

NoMethodError: undefined method `first' for #<Task:0x47631bc9> 
     from org/jruby/RubyKernel.java:227:in `method_missing' 
     from /Users/larry/.rvm/gems/jruby-1.6.7@entercamp/gems/mongoid-2.4.6/lib/mongoid/attributes.rb:166:in `method_missing' 
     from /Users/larry/.rvm/gems/jruby-1.6.7@entercamp/gems/mongoid-2.4.6/lib/mongoid/relations/embedded/many.rb:292:in `substitute' 
     from org/jruby/RubyProc.java:270:in `call' 
     from org/jruby/RubyProc.java:220:in `call' 
     from /Users/larry/.rvm/gems/jruby-1.6.7@entercamp/gems/mongoid-2.4.6/lib/mongoid/relations/embedded/atomic.rb:61:in `atomically' 
     from org/jruby/RubyProc.java:270:in `call' 
     from org/jruby/RubyProc.java:220:in `call' 
     from /Users/larry/.rvm/gems/jruby-1.6.7@entercamp/gems/mongoid-2.4.6/lib/mongoid/relations/embedded/atomic.rb:82:in `count_executions' 
     from /Users/larry/.rvm/gems/jruby-1.6.7@entercamp/gems/mongoid-2.4.6/lib/mongoid/relations/embedded/atomic.rb:60:in `atomically' 
     from /Users/larry/.rvm/gems/jruby-1.6.7@entercamp/gems/mongoid-2.4.6/lib/mongoid/relations/embedded/many.rb:290:in `substitute' 
     from org/jruby/RubyKernel.java:1787:in `tap' 
     from /Users/larry/.rvm/gems/jruby-1.6.7@entercamp/gems/mongoid-2.4.6/lib/mongoid/relations/embedded/many.rb:283:in `substitute' 
     from /Users/larry/.rvm/gems/jruby-1.6.7@entercamp/gems/mongoid-2.4.6/lib/mongoid/relations/accessors.rb:128:in `tasks=' 
     from org/jruby/RubyProc.java:270:in `call' 
     from org/jruby/RubyKernel.java:2080:in `send' 

就是这种定义是不可能的或者还有其他问题？

Answer 1

听起来好像你想要在用户内部存储单独的任务，并在该任务内部存储发送者用户。

在这种情况下，你想要做什么的轨道控制台进行测试，这将是：

> assignee = User.where(...).first 
> assigner = User.where(...).first 
> task = Task.new 
> task.sender = assigner 
> task.save 
> assignee.task = task 
> assignee.save 

，对吗？在这种情况下，我认为你的类可能是这样的：

任务

class Task 
    embedded_in :assignee, :class_name => "User" 
    embeds_one :assigner, :class_name => "User" 
end 

用户

class User 
    embeds_many :tasks 
    embedded_in :task 
end