Rails 3的語法與attr_accessible和創建關聯的對象

Question

考慮以下模型：

rails g model Menu name:string 
rails g model MenuHeader mh_name:string menu_id:integer 

class Menu < ActiveRecord::Base 
    has_many :menu_headers 
    attr_accessible :menu_headers_attributes, :name 
end 

class MenuHeader < ActiveRecord::Base 
    belongs_to :menu 
end 

嘗試通過鐵軌控制檯添加，我得到：

Menu.create({"name"=>"My first menu",:menu_headers_attributes=>{:mh_name => "here is my name"}}) 
ActiveRecord::UnknownAttributeError: unknown attribute: menu_headers_attributes 

什麼會添加這個正確的語法？

我可以刪除attr_accessible嗎？

THX

編輯＃1從布里克的回答（THX順便說一句，真的很感謝！）

class Menu < ActiveRecord::Base 
    has_many :menu_headers 
    attr_accessible :name 
    accepts_nested_attributes_for :menu_headers 
end 

ruby-1.9.2-p290 :001 > Menu.create({"name"=>"My first menu",:menu_headers_attributes=>{"mh_name" => "here is my name"}}) 
TypeError: can't convert Symbol into Integer 
from /Users/jt/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/nested_attributes.rb:395:in `[]' 
from /Users/jt/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/nested_attributes.rb:395:in `block in assign_nested_attributes_for_collection_association' 
from /Users/jt/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/nested_attributes.rb:395:in `map' 
from /Users/jt/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/nested_attributes.rb:395:in `assign_nested_attributes_for_collection_association' 
from /Users/jt/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/nested_attributes.rb:287:in `menu_headers_attributes=' 
from /Users/jt/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/base.rb:1745:in `block in assign_attributes' 

Answer 1

您需要添加：

accepts_nested_attributes_for :menu_headers 

到您的菜單模式。這會將menu_headers_attributes作爲屬性添加到Menu。