使用用户表单数据，如何仅将字段的前五位数字传输到我的数据库字段(交叉发布)

<form action="/submit" method="POST">
  <input type="text" name="data" placeholder="请输入数据" required>
  <button type="submit">提交</button>
</form>

const express = require('express');
const mysql = require('mysql');

const app = express();
const connection = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'password',
  database: 'mydatabase'
});

app.use(express.urlencoded({ extended: true }));

app.post('/submit', (req, res) => {
  const inputData = req.body.data;
  const extractedData = inputData.substring(0, 5);

  connection.query('INSERT INTO mytable (field) VALUES (?)', [extractedData], (error, results) => {
    if (error) throw error;
    res.send('数据已成功提交到数据库');
  });
});

app.listen(3000, () => {
  console.log('服务器已启动');
});