如果不需要使用操作系統和品牌名稱作為鍵，我有這樣的解決方案。
我會像這樣設置我的模式：
const mongoose = require("mongoose");
const operatingSystemSchema = new mongoose.Schema({
name: {
type: String,
required: true
}
});
const brandSchema = new mongoose.Schema({
name: {
type: String,
required: true
}
});
const productSchema = new mongoose.Schema({
model: {
type: String,
required: true
},
operatingSystem: {
type: mongoose.Schema.Types.ObjectId,
ref: "OperatingSystem"
},
brand: {
type: mongoose.Schema.Types.ObjectId,
ref: "Brand"
}
});
module.exports = {
OperatingSystem: mongoose.model("OperatingSystem", operatingSystemSchema),
Brand: mongoose.model("Brand", brandSchema),
Product: mongoose.model("Product", productSchema)
};
根據模式插入文檔后，我們可以使用以下聚合按操作系統和品牌進行分組：
db.products.aggregate([
{
$lookup: {
from: "operatingsystems",
localField: "operatingSystem",
foreignField: "_id",
as: "operatingSystems"
}
},
{
$lookup: {
from: "brands",
localField: "brand",
foreignField: "_id",
as: "brands"
}
},
{
$unwind: "$operatingSystems"
},
{
$unwind: "$brands"
},
{
$replaceRoot: {
newRoot: {
$mergeObjects: [
"$$ROOT",
{
operatingSystem: "$operatingSystems.name",
brand: "$brands.name"
}
]
}
}
},
{
$project: {
brands: 0,
operatingSystems: 0
}
},
{
$group: {
_id: {
"operatingSystem": "$operatingSystem",
"brand": "$brand",
},
products: {
$push: "$$ROOT"
}
}
},
{
$group: {
"_id": "$_id.operatingSystem",
"data": {
"$push": {
"brand": "$_id.brand",
"models": "$products.model"
}
}
}
},
{
$project: {
"OS": "$_id",
"_id": 0,
"data": 1
}
}
])
操場
以及快遞方面的示例路線：
router.get("/", async (req, res) => {
const result = await Product.aggregate([
{
$lookup: {
from: "operatingsystems",
localField: "operatingSystem",
foreignField: "_id",
as: "operatingSystems"
}
},
{
$lookup: {
from: "brands",
localField: "brand",
foreignField: "_id",
as: "brands"
}
},
{
$unwind: "$operatingSystems"
},
{
$unwind: "$brands"
},
{
$replaceRoot: {
newRoot: {
$mergeObjects: [
"$$ROOT",
{
operatingSystem: "$operatingSystems.name",
brand: "$brands.name"
}
]
}
}
},
{
$project: {
brands: 0,
operatingSystems: 0
}
},
{
$group: {
_id: {
operatingSystem: "$operatingSystem",
brand: "$brand"
},
products: {
$push: "$$ROOT"
}
}
},
{
$group: {
_id: "$_id.operatingSystem",
data: {
$push: {
brand: "$_id.brand",
models: "$products.model"
}
}
}
},
{
$project: {
OS: "$_id",
_id: 0,
data: 1
}
}
]);
res.send(result);
});
結果將如下所示：
[
{
"OS": "Windows",
"data": [
{
"brand": "Nokia",
"models": [
"Nokia 7.2"
]
}
]
},
{
"OS": "Android",
"data": [
{
"brand": "OnePlus",
"models": [
"oneplus7",
"oneplu6"
]
},
{
"brand": "Samsung",
"models": [
"S7",
"S6"
]
}
]
},
{
"OS": "IOS",
"data": [
{
"brand": "Apple",
"models": [
"Iphone7",
"Iphone6"
]
}
]
}
]
