如何避免在MySQL中使用nodejs和reactjs插入未定义的内容？

import React from 'react';
import { Formik, Form, Field, ErrorMessage } from 'formik';
import * as Yup from 'yup';

const validationSchema = Yup.object({
  name: Yup.string().required('Name is required'),
  email: Yup.string().email('Invalid email').required('Email is required'),
});

const MyForm = () => (
  <Formik
    initialValues={{ name: '', email: '' }}
    validationSchema={validationSchema}
    onSubmit={(values) => {
      // 提交数据到后端
      console.log(values);
    }}
  >
    {({ isSubmitting }) => (
      <Form>
        <Field type="text" name="name" />
        <ErrorMessage name="name" component="div" />

        <Field type="email" name="email" />
        <ErrorMessage name="email" component="div" />

        <button type="submit" disabled={isSubmitting}>
          Submit
        </button>
      </Form>
    )}
  </Formik>
);

export default MyForm;

const express = require('express');
const Joi = require('joi');
const app = express();

app.use(express.json());

const schema = Joi.object({
  name: Joi.string().required(),
  email: Joi.string().email().required(),
});

app.post('/submit', (req, res) => {
  const { error } = schema.validate(req.body);
  if (error) {
    return res.status(400).send(error.details[0].message);
  }
  // 插入数据到MySQL
  res.send('Data inserted successfully');
});

app.listen(3000, () => console.log('Server running on port 3000'));