Mongomapper many to many issue with Array

问题

I would like to list all the task names for the User form the user's tasklist

But when I use the code below I get the following message:

undefined method `task_id' for ...

Here are my classes:

class User
  include MongoMapper::Document
  key :name, String
  key :tasklist, Array # I need this to hold ObjIds

  many :tasks, :in => :tasklist, :class_name => 'Task'

  def add(taskid)
    a = self.new
    a.task_id << taskid
    a.save
end

class Task
  include MongoMapper::Document
  key :name, String

  many :users
end  

回答1:

I used:

a = self.new
a.tasklist = [object1,object2]
a.save

Then I can iterate through all the object references using:

a = User.find(a.id)
a.tasks.each do |task|
  puts task.name
end

来源：https://stackoverflow.com/questions/24724393/mongomapper-many-to-many-issue-with-array