MySQL连接池(Pool)常用方法详解

const mysql = require('mysql2/promise'); // 使用Promise版本

const pool = mysql.createPool({
  host: 'localhost',
  user: 'root',
  password: 'password',
  database: 'test',
  waitForConnections: true,
  connectionLimit: 10, // 最大连接数
  queueLimit: 0 // 无限制的排队请求
});

const [rows] = await pool.query('SELECT * FROM users WHERE age > ?', [18]);

const [rows] = await pool.execute('SELECT * FROM products WHERE price > ?', [100]);

const connection = await pool.getConnection();
try {
  // 使用connection执行查询
} finally {
  connection.release(); // 必须释放
}

await connection.beginTransaction();

await connection.commit();

await connection.rollback();

await pool.end(); // 关闭所有连接

const name = pool.escape(userInput); // 防止SQL注入

const tableName = pool.escapeId('user table');

const connection = await pool.getConnection();
try {
  await connection.beginTransaction();
  
  // 执行多个操作
  await connection.query('UPDATE accounts SET balance = balance - ? WHERE id = ?', [100, 1]);
  await connection.query('UPDATE accounts SET balance = balance + ? WHERE id = ?', [100, 2]);
  
  await connection.commit();
} catch (err) {
  await connection.rollback();
  throw err;
} finally {
  connection.release();
}

pool.on('acquire', (connection) => {
  console.log('Connection %d acquired', connection.threadId);
});

pool.on('release', (connection) => {
  console.log('Connection %d released', connection.threadId);
});