Rails的嵌套的聯接

Question

廠商

has_many :product 

產品

has_many :part 

PartsRequest

belongs_to :part 
belongs_to :manufacturer 

我試圖做一些PartsRequest 例如製造商A正試圖從製造商B處獲得零件請求如何加入零件，然後從零件加入產品中？

Answer 1

scope :incoming_requests, lambda{|mid| joins(:part => :product).where(:product => {:manufacturer_id => mid}) }