当我不知道文档 ID 时，如何使用 mongoose 查询子文档

Question

I have been tasked with rebuilding a more monolithic database using mongo db. In this database, I have a product document which looks like this.

{
  product_id: 4.
  questions: [
    {
      question_id: 10,
      question_text: "hello?",
      helpfulness: 0
    },
    {
      question_id: 11,
      question_text: "goodbye?",
      helpfulness: 1
    }
  ]
}

I will receive a request to my server that includes the question_id (ie 11) and I will need to increment the question's helpfulness. I have looked everywhere, but I cant seem to find a method to query my database with only the question id and update that question without first knowing the product Id. Is there a way to do this? thanks so much for any help!

Answer 1

I think that given query can help you to fetch and update your product document :

db.product.update({questions: {$elemMatch: {question_id:'11'}}},{
     $inc: {"questions.helpfulness": 1}
})

Here $inc is used to increment your helpfulness value by 1

Answer 2

Here you go, first you need to match the question id and then inc the relative helpfulness by 1. Do try this out

db.collection.updateOne({'questions.question_id' : 11}, {$inc : {"questions.$.helpfulness" : 1}})

Output :

{ 
    "_id" : ObjectId("5f891ca72857d128c68bf01a"), 
    "product_id" : 4.0, 
    "questions" : [
        {
            "question_id" : 10.0, 
            "question_text" : "hello?", 
            "helpfulness" : 0.0
        }, 
        {
            "question_id" : 11.0, 
            "question_text" : "goodbye?", 
            "helpfulness" : 2.0
        }
    ]
}