如何将嵌套属性保存在 MongoDB 的新集合中的新文档中？

Question

I am new to MongoDB and still trying to learn more. I am trying to create a new document in one collection by copying nested properties from another collection. For example:

userId: 12345
products: [
    {
        "productId": "123",
        "quantity": 1
    },
    {
        "productId": "124",
        "quantity": 2,

    }
]

I am trying to get the nested "productid" with their corresponding quantity to be saved to a new document in a new collection.

Answer 1

You can simply get data from one collection and store into an array and dump into another. You can also perform some operations on that array if you want. Here is working example....

 const dataFromOneCollection = [ { userId: 12345, products: [ { productId: "123", quantity: 1, }, { productId: "124", quantity: 2, }, ], }, { userId: 6789, products: [ { productId: "456", quantity: 1, }, { productId: "245", quantity: 2, }, ], }, ]; // map data and flat it to one array const dataToStoreAnotherCollection = dataFromOneCollection.map(i => i.products).flat(1); console.log(dataToStoreAnotherCollection); // insert data to another collection db.collection("products").insertMany(dataToStoreAnotherCollection);