如何插入使用mongoid，而不必做額外的查詢？

Question

當我這樣做時，有什麼辦法可以防止查詢db的問題。

has_and_belongs_to_many :followed_questions, class_name: 'Question', inverse_of: nil 
qid = "501928374" 
q = Question.find(qid) 
self.followed_questions << q unless self.followed_questions.include?(q) 
self.save 

我想這樣做：

has_and_belongs_to_many :followed_questions, class_name: 'Question', inverse_of: nil 
qid = "501928374"  
self.followed_questions << qid unless self.followed_questions.include?(qid) 
self.save 

Answer 1

是的，你可以通過指定id，而不是文件

has_and_belongs_to_many :followed_questions, class_name: 'Question', inverse_of: nil 
qid = "501928374"  
self.followed_question_ids << qid unless self.followed_question_ids.include?(qid) 
self.save 

做