Question

使用Nodejs，Express我想将数据作为整数存储到数据库中并找到Mean。目前，数据（名称和校园）都存储为String，当$ avg用于查找平均值时，db返回null值。数据库中的表是Name和Campus。名称必须为String，Campus必须为整数。 $ avg在Campus with Same Names上执行。这是我的server.js文件

const express = require('express');
var path = require('path');

const bodyParser = require('body-parser')
const MongoClient = require('mongodb').MongoClient


MongoClient.connect('mongodb://dbname:passw@d1111.mlab.com:11111/rank', (err, database) => {
  if (err) return console.log(err)
  db = database
  app.listen(8080, () => {
    console.log('listening on 8080')
  })
})

const app = express();
app.set('view engine', 'ejs')
app.use(express.static(path.join(__dirname, 'public')));



app.get('/', (req, res) => {
  db.collection('colleges').find().toArray((err, result) => {
    if (err) return console.log(err)
    // renders index.ejs
    res.render('index.ejs', {colleges: result})
  })
})

app.get('/answers', (req, res) => {
  db.collection('colleges').find().toArray((err, result) => {
    if (err) return console.log(err)
    // renders index.ejs
    res.render('index.ejs', {colleges: result})
  })
})


app.use(bodyParser.urlencoded({extender: true}))


app.post('/colleges', (req, res) =>{
    db.collection('colleges').save(req.body, (err, result) =>{
        if (err) return console.log(err)

        console.log('saved to database')
        console.log(JSON.stringify(req.body))

        res.redirect('/')
    })
})

这是我的index.ejs文件有这个表单

<form action="/colleges" method="POST">
  <input type="text" placeholder="name" name="name">
  <input type="number" placeholder="campus" name="campus">
  <button type="submit">Submit</button>
</form>

计算平均值的代码

db.colleges.aggregate([
           { $match: { college: "RVCE"}}, 
           { $group: {_id:"campus", total: {$avg: "$campus"}}}
           ])

Answer 1

我猜你可以做到这一点，

app.post('/colleges', (req, res) =>{
req.body.campus = parseInt(req.body.campus);
db.collection('colleges').save(req.body, (err, result) =>{
    if (err) return console.log(err)

    console.log('saved to database')
    console.log(JSON.stringify(req.body))

    res.redirect('/')
});

如何在NodeJS中将数据作为整数而不是字符串存储到MongoDB中？

1 个答案: