express链接数据库
时间: 2023-11-02 18:10:18 浏览: 31
在 Node.js 中使用 Express 框架连接数据库需要使用相应的数据库驱动程序。以下是连接 MySQL 数据库的示例代码:
1. 安装 MySQL 驱动程序
```
npm install mysql
```
2. 引入 MySQL 驱动程序
```javascript
const mysql = require('mysql');
```
3. 创建数据库连接
```javascript
const connection = mysql.createConnection({
host: 'localhost',
user: 'root',
password: 'password',
database: 'my_database'
});
```
4. 连接数据库
```javascript
connection.connect((err) => {
if (err) {
console.error('error connecting: ' + err.stack);
return;
}
console.log('connected as id ' + connection.threadId);
});
```
5. 查询数据
```javascript
connection.query('SELECT * FROM my_table', (error, results, fields) => {
if (error) throw error;
console.log('The solution is: ', results);
});
```
完整代码示例:
```javascript
const express = require('express');
const mysql = require('mysql');
const app = express();
const connection = mysql.createConnection({
host: 'localhost',
user: 'root',
password: 'password',
database: 'my_database'
});
connection.connect((err) => {
if (err) {
console.error('error connecting: ' + err.stack);
return;
}
console.log('connected as id ' + connection.threadId);
});
app.get('/', (req, res) => {
connection.query('SELECT * FROM my_table', (error, results, fields) => {
if (error) throw error;
res.send(results);
});
});
app.listen(3000, () => {
console.log('Server started on port 3000');
});
```