egg学习笔记第二十八天：mongoose当中的聚合管道

mongoose当中的聚合管道

聚合管道主要就可以实现表关联。

model>order.js

var mongoose = require("./db.js");

var OrderSchema = mongoose.Schema({
  order_id: String,
  uid: Number,
  trade_no: String,
  all_price: Number,
  all_num: Number
});

module.exports = mongoose.model("Order", OrderSchema, "order");

model>order_item.js

var mongoose = require("./db.js");

var OrderItemSchema = mongoose.Schema({
  order_id: String,
  title: String,
  price: Number,
  num: Number
});

module.exports = mongoose.model("OrderItem", OrderItemSchema, "order_item");

app.js

var OrderModel = require("./model/order.js");

// 查询order表的数据
OrderModel.find({}, function(err, docs) {
  console.log(docs);
});

app.js order表关联order_item表

var OrderModel = require("./model/order.js");

// // 查询order表的数据
// OrderModel.find({}, function(err, docs) {
//   console.log(docs);
// });
OrderModel.aggregate(
  [
    {
      $lookup: {
        from: "order_item",
        localField: "order_id",
        foreignField: "order_id",
        as: "items"
      }
    }
  ],
  function(err, docs) {
    if (err) {
      console.log(err);
      return;
    }
    console.log(JSON.stringify(docs));
  }
);

[
    {
        "_id": "5e85a2d513e466f7ac6a236f",
        "order_id": "1",
        "uid": 10,
        "trade_no": "111",
        "all_price": 100,
        "all_num": 2,
        "items": [
            {
                "_id": "5e85a2d613e466f7ac6a2372",
                "order_id": "1",
                "title": "商品鼠标1",
                "price": 50,
                "num": 1
            },
            {
                "_id": "5e85a2d613e466f7ac6a2373",
                "order_id": "1",
                "title": "商品键盘2",
                "price": 50,
                "num": 1
            },
            {
                "_id": "5e85a2d613e466f7ac6a2374",
                "order_id": "1",
                "title": "商品键盘3",
                "price": 0,
                "num": 1
            }
        ]
    },
    {
        "_id": "5e85a2d613e466f7ac6a2370",
        "order_id": "2",
        "uid": 7,
        "trade_no": "222",
        "all_price": 90,
        "all_num": 2,
        "items": [
            {
                "_id": "5e85a2d613e466f7ac6a2375",
                "order_id": "2",
                "title": "牛奶",
                "price": 50,
                "num": 1
            },
            {
                "_id": "5e85a2d613e466f7ac6a2376",
                "order_id": "2",
                "title": "酸奶",
                "price": 40,
                "num": 1
            }
        ]
    },
    {
        "_id": "5e85a2d613e466f7ac6a2371",
        "order_id": "3",
        "uid": 9,
        "trade_no": "333",
        "all_price": 20,
        "all_num": 6,
        "items": [
            {
                "_id": "5e85a2d613e466f7ac6a2377",
                "order_id": "3",
                "title": "矿泉水",
                "price": 2,
                "num": 5
            },
            {
                "_id": "5e85a2d713e466f7ac6a2378",
                "order_id": "3",
                "title": "毛巾",
                "price": 10,
                "num": 1
            }
        ]
    }
]

app.js order表关联order_item表 all_price字段 大于90

var OrderModel = require("./model/order.js");

// // 查询order表的数据
// OrderModel.find({}, function(err, docs) {
//   console.log(docs);
// });
OrderModel.aggregate(
  [
    {
      $lookup: {
        from: "order_item",
        localField: "order_id",
        foreignField: "order_id",
        as: "items"
      }
    },
    {
      $match: { all_price: { $gte: 90 } }
    }
  ],
  function(err, docs) {
    if (err) {
      console.log(err);
      return;
    }
    console.log(JSON.stringify(docs));
  }
);

根目录：order.js 查询id为 5e85a2d613e466f7ac6a2373 的数据

// 查询order_item，找出商品名称是酸奶的商品，酸奶这个该商品对应的订单的订单号，以及订单的总价格。
var OrderItemModel = require("./model/order_item.js");

var OrderModel = require("./model/order.js");

OrderItemModel.find({ _id: "5e85a2d613e466f7ac6a2373" }, function(err, docs) {
  console.log(docs);
});

 

来源：oschina

链接：https://my.oschina.net/u/4446873/blog/4267566