给mysql字段增加唯一性

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

ALTER TABLE users ADD UNIQUE (email);

CREATE TABLE orders (
    id INT AUTO_INCREMENT PRIMARY KEY,
    customer_id INT,
    order_date DATE,
    UNIQUE (customer_id, order_date)
);

ALTER TABLE orders ADD UNIQUE (customer_id, order_date);

INSERT INTO users (email, name) VALUES ('test@example.com', 'Test User')
ON DUPLICATE KEY UPDATE name = 'Test User';

try:
    cursor.execute("INSERT INTO users (email, name) VALUES (%s, %s)", ('test@example.com', 'Test User'))
    connection.commit()
except mysql.connector.IntegrityError as err:
    print(f"Error: {err}")

ALTER TABLE users DROP INDEX email;