mysql多字段联合唯一约束

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    email VARCHAR(255) NOT NULL,
    username VARCHAR(255) NOT NULL,
    UNIQUE KEY unique_email_username (email, username)
);

import mysql.connector

try:
    conn = mysql.connector.connect(user='user', password='password', host='host', database='database')
    cursor = conn.cursor()
    query = "INSERT INTO users (email, username) VALUES (%s, %s)"
    values = ('user@example.com', 'unique_username')
    cursor.execute(query, values)
    conn.commit()
except mysql.connector.IntegrityError as err:
    print(f"Error: {err}")
finally:
    cursor.close()
    conn.close()

SHOW CREATE TABLE users;