猫鼬保存内部文档创建一个包含文档的文档

Question

我正在学习 mongoose，我对如何保存多个文档有疑问：

// Product.js
const categorySchema = mongoose.Schema(
  { name: String },
  { collection: "categories" }
);
const productSchema = mongoose.Schema(
  { name: String, category: categorySchema },
  { collection: "products" }
);
modules.exports = mongoose.model("Product", productSchema);

我的想法是，当我以这种方式创建产品时

const Product = require("./Product.js")
const product = new Product({name: 'Soccer Ball', category: {name: "Sports"})
await product.save()

我想获取 collection 产品中的文档以及 collection 类别中的文档

怎么可能

提前致谢

PD：我得到了这个，但类别没有保存在 collection

{
  "msg": "Product created succesfully",
  "ok": true,
  "product": {
    "name": "Soccer ball",
    "category": {
      "name": "Sports",
      "_id": "6275df4c8149967bea21e7c0"
    },
    "_id": "6275df4c8149967bea21e7bf",
    "__v": 0
  }
}

Answer 1

您应该将 Product 的 category 定义为 ref 属性：

// Product.js
const categorySchema = mongoose.Schema(
    { name: String },
    { collection: 'categories' }
  );
const productSchema = mongoose.Schema(
    {
      name: String,
      category: { type: mongoose.Schema.Types.ObjectId, ref: 'categories' },
    },
    { collection: 'products' }
  );
modules.exports = {
    Category: mongoose.model('Category', categorySchema),
    Product: mongoose.model('Product', productSchema),
}

为此，您需要将类别的 _id 分配给新的 Product:

const { Category } = require("./Product.js")
const { Product } = require("./Product.js")
// Create category (supposing it is not present)
const category = new Category({ name: "Sports" })
await category.save()
// Add category _id to product
const product = new Product({name: 'Soccer Ball', category: category._id})
await product.save()

最后，您将能够使用 populate 检索产品：

const product = await Product.findById(<product_id>).populate('categories').exec()

此查询应给出与之前相同的结果，但 Category 数据将从 Category 集合中的引用加载。

猫鼬保存内部文档创建一个包含文档的文档

mongoose save internal documents creating a document that contains a document

mongoose

mongodb

node.js