为什么我不能使用 db.collection.countDocuments()

Question

我想获取 'image' 集合中的文档数。

我的密码是

var express = require('express');
var mongoose = require('mongoose');
var bodyParser = require('body-parser');
var app = express();

app.set('view engine', 'ejs');
app.use(express.static(__dirname+'/public'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended:true}));

dburl = "mongodb+srv://...";
mongoose.connect(dburl);
var db = mongoose.connection;

//...

var imageSchema = mongoose.Schema({
  image_name:{type:String, required:true, unique:true}
});
var Image = mongoose.model('image', imageSchema);
var Dcount = db.image.countDocuments({});

但是控制台： enter image description here

Answer 1

countDocuments() 可直接在型号

上使用

你应该Image.countDocuments()

Image.countDocuments({}, function (err, count) {
    if (err){
        console.log(err)
    }else{
        console.log("Count :", count)
    }
});

为什么我不能使用 db.collection.countDocuments()

Why i can't use db.collection.countDocuments()

node.js

mongodb

mongoose