问Nodejs，Express mysql总是返回ER_BAD_DB_ERROR

EN

  code: 'ER_BAD_DB_ERROR',
  errno: 1049,
  sqlMessage: "Unknown database 'moneydb'",
  sqlState: '42000',
  fatal: true

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 usersRouter = require('./routes/users');

var app = express();

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

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('/users', usersRouter);

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

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

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

// connection setup
const connection = mysql.createConnection({
    host: 'localhost',
    user: 'root',
    password: '',
    database: 'moneydb'
});


// connect to database
connection.connect((err) => {
    if (err) {
        console.log('Not connected to database');
        throw err;
    } else {
        console.log('Connected to database');
    }
});

// make connection global
global.db = connection;

/*
*  Every page we declare here will be under the index path
*  localhost:3000/ will render home page
*  localhost:3000/disheslist will be under the home page path and will render the disheslist
* */

/* GET home page. */
router.get('/', function (req, res, next) {
    res.render('index', {title: 'Express'});
});

/*GET dish list. */
/*render contains views(pug files)*/
router.get('/dishes', function (req, res, next) {
    let query = "SELECT * FROM `dish` ORDER BY id ASC";

    // execute query
    db.query(query, (err, result) => {
        if (err) {
            // we should redirect to an error page maybe
            res.redirect('/');
        }

        if (result) {
            res.render('dishes', {tableData: result});
        } else {
            res.send("Error");
        }
    });
});

module.exports = router;

doctype html
html
    head
        title = title
        link(rel='stylesheet', href='/stylesheets/style.css')
    body
    table
        thead
            tr
            th id
            th name
            tbody