mongoDb - 如何从嵌套数组中删除 object

Question

    "ProductCategory": [
        {
          "_id": "6246e0d09b16cf549256ed75",
          "name": "Arduino Boards",
          "desc": "this is for demo purpose",
          "date": "2022-03-31T18:30:00.000Z",
          "products": [
            {
              "name": "Arduino Uno R3 CH340G",
              "imgUrl": "",
              "price": "799",
              "desc": "",
              "_id": "6246e1fb9b16cf549256ed77"
            },
            {
              "name": "Arduino Nano V3.0 ATMEGA 328P (with USB Cable)",
              "imgUrl": "",
              "price": "599",
              "desc": "",
              "_id": "6246e3049b16cf549256ed79"
            }
          ]
        },
        {
          "_id": "6246e32d9b16cf549256ed7d",
          "name": "Sensors",
          "desc": "this is for demo purpose",
          "date": "2022-03-31T18:30:00.000Z",
          "products": [
            {
              "name": "PU6050 Gyroscope Sensor",
              "imgUrl": "",
              "price": "129",
              "desc": "",
              "_id": "6246e3d29b16cf549256ed7f"
            },
            {
              "name": "CCS811 Carbon Monoxide Gas Sensor",
              "imgUrl": "",
              "price": "1799",
              "desc": "",
              "_id": "6246e3d29b16cf549234ea3r"
            }
          ]
        }

This is a data in mongoDB with the collection named as ProductCategory . I want to find the product with _id "6246e3049b16cf549256ed79" which is "Arduino Nano V3.0 ATMEGA 328P (with USB Cable)" . How can I find it and also delete it.

Answer 1

In order to delete from a nested array, you can use pipeline update and $filter for this:

db.ProductCategory.update({
  "products._id": idToDelete
},
[
  {
    $set: {
      products: {
        $filter: {
          input: "$products",
          as: "item",
          cond: {$ne: ["$$item._id", idToDelete]}
        }
      }
    }
  }
])

This will filter the products array to contain only items that their id is not idToDelete .

You can see it works on the playground

In order to just find the document, you can use:

db.ProductCategory.find({"products._id": idToDelete})

Answer 2

db.categories.deleteOne( {"_id": ObjectId("6246e3049b16cf549256ed79")});

https://www.mongodb.com/docs/manual/tutorial/remove-documents/