mysql数据库怎么重复写入

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(255) UNIQUE,
    email VARCHAR(255) UNIQUE
);

-- 使用INSERT IGNORE忽略重复插入
INSERT IGNORE INTO users (username, email) VALUES ('john_doe', 'john@example.com');

-- 使用ON DUPLICATE KEY UPDATE更新已有记录
INSERT INTO users (username, email) VALUES ('john_doe', 'john@example.com')
ON DUPLICATE KEY UPDATE email = 'john@example.com';

import mysql.connector

def insert_user(username, email):
    conn = mysql.connector.connect(user='user', password='password', host='host', database='database')
    cursor = conn.cursor()
    
    # 检查用户是否存在
    cursor.execute("SELECT id FROM users WHERE username = %s OR email = %s", (username, email))
    result = cursor.fetchone()
    
    if result is None:
        cursor.execute("INSERT INTO users (username, email) VALUES (%s, %s)", (username, email))
        conn.commit()
    else:
        print("User already exists.")
    
    cursor.close()
    conn.close()