mongoid - 我如何使用 mongoid 插入而不需要做额外的查询？

Question

有什么方法可以防止我在执行此操作时不必向数据库查询问题。

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

我想做这个：

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，您可以通过分配 ID 而不是文档来完成

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