node.js - 使用node.js从mongoDB获取数据，连接有效但没有数据显示

Question

所以我使用node.js创建了一个应用程序并将其连接到mongoDB，但是没有显示数据，它只是显示空的json数据文件[]。数据库名称为 sample_geospatial，集合名为 shipwrecks，所有 IP 地址都可以连接。

为什么我在浏览器中显示数据的任务没有成功？

This is my app.js

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');

var indexRouter = require('./routes/index');
var shipwrecksRouter = require('./routes/shipwrecks');

var app = express();

// Database connect with moongoose
var mongoose = require('mongoose');
mongoose.connect('mongodb+srv://gockzor:***********@cluster0-boypg.azure.mongodb.net/test?retryWrites=true&w=majority');
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function (callback) {
    console.log("Kopplingen lyckades!");
});

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({
    extended: false
}));

app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', indexRouter);
app.use('/shipwrecks', shipwrecksRouter);

// catch 404 and forward to error handler
app.use(function (req, res, next) {
    next(createError(404));
});
module.exports = app;

This is my model

var mongoose = require('mongoose');

var WrecksSched = new mongoose.Schema({
    recrd: String,
    vesslterms: String,
    feature_type: String,
    chart: String,
    latdec: Number,
    londec: Number,
    gp_quality: String,
    depth: String,
    sounding_type: String,
    history: String,
    quasou: String,
    watlev: String,
    coordinates: Array,
}, {
    collection: 'shipwrecks'
});
module.exports = mongoose.model('ShipwrecksModel', WrecksSched);

This is my routes file

var express = require('express');
var router = express.Router();

var mongoose = require('mongoose');
var ShipwrecksModel = require('../models/ShipwrecksModel.js');

router.get('/', function (req, res, next) {
    ShipwrecksModel.find(function (err, wrecks) {
        if (err) return next(err);
        else {
            res.json(wrecks);
        }
    });
});
module.exports = router;

Answer 1

将其作为答案:

如果您在 api 响应中看到 [] 而不是错误 -

then the issue could either be you're not able to connect to proper collection name(if you're sure collection has data in it) or correct db where your collection exists.

因此，从您的数据库网址来看:

'mongodb+srv://gockzor:***********@cluster0-boypg.azure.mongodb.net/test?retryWrites=true&w=majority'

您已连接到test数据库，那么您的收藏shipwrecks就是在您的数据库中吗？如果不是，请尝试在连接后切换到实际数据库，或将 url 中的 test 替换为实际数据库名称。

所以默认情况下你会得到一个 url w.r.t.当您从 Atlas mongoDB 获取数据库时，将其发送到 test 数据库。因此，请一次性将其替换为 url，或者您可以在连接到数据库后使用 useDb 函数切换代码。 例如。 :-

从代码切换数据库的基本方法::

 async function myDbConnection() {

    const url = mongodb+srv://gockzor:***********@cluster0-boypg.azure.mongodb.net/test?retryWrites=true&w=majority';

    try {
        await mongoose.connect(url, { useNewUrlParser: true });
        console.log('Connected Successfully')
        mongoose.connection.useDb('myDB'); // Switching happens here..
        /**
         * Do some DB transaction with mongoose models as by now models has already been registered to created DB connection
         */
    } catch (error) {
        console.log('Error connecting to DB ::', error);
    }
}

或者你可以直接在 url 中添加类似的内容::

const dbUrl = mongodb+srv://gockzor:***********@cluster0-boypg.azure.mongodb.net/myDB?retryWrites=true&w=majority'