我正在為帶有nodeJS的服務器使用express開發一個網頁。我在注冊頁面上，并且正在嘗試驗證用戶插入的數據，但是當我進行查詢時出現錯誤。auth.jsconst express = require('express');const router = express.Router();const { bd } = require('../database');const help_functions = require('../lib/common');router.post('/signup', async (req,res) => {    const fullname = req.body['fullname'];    const email = req.body['email'];    const username = req.body['username'];    const password = req.body['password'];    const password_repeat = req.body['password_repeat'];    var validation_msg = help_functions.validateSignUp(fullname, email, username, password, password_repeat);    validation_msg = await help_functions.checkRepeatedUserEmail(email);});數據庫.jsconst mysql = require('mysql');const { promisify } = require('util');const database =  { // Database credentials }const bd = mysql.createPool(database);bd.getConnection((err,connection) => {    if (err) {        if (err.code === 'PROTOCOL_CONNECTION_LOST') {            console.error('Database connection failed !');        }        if (err.code === 'ER_CON_COUNT_ERROR') {            console.error('Database has too many connections !');        }        if (err.code === 'ECONNREFUSED') {            console.error('Database connection was refused !');        }    }    if (connection) {        connection.release();        console.log('Database is connected !');        return;    }});bd.query = promisify(bd.query);module.exports = bd;common.jsconst { bd } = require('../database');const helper_functions = {}helper_functions.validateSignUp = (fullname, email, username, password, password_repeat) => {    if (fullname === '' || email === '' || username === '' || password === '' || password_repeat === '') {        return 'All the fields had to be completed!';    }    if (!(password.length >= 8 && (/\d/g.test(password) && (/[A-Z]/.test(password)))) ) {        return 'The password needs to contain at least one capital letter, a number and 8 digits!';    }有誰知道發生了什么？？謝謝閱讀！