express中MongoDB查询问题

Question

最近刚开始学express，在敲mdn的实践，想要小修改一下，遇上一点问题，先上代码：

//tagController.js：
const Tag = require('../models/tag');

exports.find_all = async (req, res, next) => {
        let result = await Tag.find({});
        debugger;
        res.send(result);                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
};

///./models/tag

const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const ObjectId = Schema.ObjectId;

var TagSchema = new Schema({
    context: String,
    tagId: ObjectId
    //tagId: {type: ObjectId, ref: 'Tag', required: true},
});

TagSchema
    .virtual('url')
    .get(function () {
        return '/tag/' + this._id;
    });

module.exports = mongoose.model('Tag', TagSchema, 'Tag');

//routes.js
const  express = require('express');
const  router = express.Router();
const tag_controller = require('../controllers/tagController');

router.get('/', tag_controller.find_all);

//Set up mongoose connection
var mongoose = require('mongoose');
var mongoDB = 'mongodb://****************************/test?ssl=true&replicaSet=piggybank-shard-0&authSource=admin&retryWrites=true';
const options = {
    useNewUrlParser: true,
    useCreateIndex: true,
    useFindAndModify: false,
    autoIndex: false, // Don't build indexes
    reconnectTries: Number.MAX_VALUE, // Never stop trying to reconnect
    reconnectInterval: 500, // Reconnect every 500ms
    poolSize: 10, // Maintain up to 10 socket connections
    // If not connected, return errors immediately rather than waiting for reconnect
    bufferMaxEntries: 0,
    connectTimeoutMS: 10000, // Give up initial connection after 10 seconds
    socketTimeoutMS: 45000, // Close sockets after 45 seconds of inactivity
    family: 4 // Use IPv4, skip trying IPv6

    // replicaSet: 'piggybank-shard-0',
    // ssl: true,
    // authSource: admin,
    // retryWrites: true
};
mongoose.connect(mongoDB,options);
mongoose.Promise = global.Promise;
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'MongoDB connection error:'));

数据库连接应该是正常的，能往表里插入数据，查询有问题，想问下可能是哪里写的不对，多谢:)

Answer 1

我试了下你的代码，查询是可以的，你可以看下我下面的截图：

我代码是直接copy的你上面的代码来的（就不贴代码了），所以我估计你查询不到数据，要么是你所谓的插入了数据可能插入失败了（你看下是不是把数据插入到Tag里了），要么是没有插入成功数据。