CREATE DATABASE contact_db CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
CREATE TABLE contacts (
contact_id INT AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(50) NOT NULL,
phone VARCHAR(20) UNIQUE NOT NULL,
email VARCHAR(50),
address VARCHAR(100),
company VARCHAR(50),
created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);
INSERT INTO contacts (name, phone, email, address, company) VALUES
('张三', '13800138000', 'zhangsan@example.com', '北京市朝阳区', 'ABC公司'),
('李四', '13900139000', 'lisi@example.com', '上海市浦东新区', 'XYZ集团');