帮我用python写一个简单的员工管理器，需要通过数据库进行增删改

好的，以下是一个简单的员工管理器示例，它使用 MySQL 数据库进行增删改查操作。在使用之前，需要先安装 `mysql-connector-python` 库。

import mysql.connector

# 连接数据库
cnx = mysql.connector.connect(user='username', password='password',
                              host='hostname',
                              database='database_name')
cursor = cnx.cursor()

# 添加员工
def add_employee(emp_id, name, salary):
    add_employee_query = ("INSERT INTO employees "
                          "(emp_id, name, salary) "
                          "VALUES (%s, %s, %s)")
    data = (emp_id, name, salary)
    cursor.execute(add_employee_query, data)
    cnx.commit()
    print("员工添加成功！")

# 删除员工
def delete_employee(emp_id):
    delete_employee_query = ("DELETE FROM employees "
                             "WHERE emp_id = %s")
    data = (emp_id,)
    cursor.execute(delete_employee_query, data)
    cnx.commit()
    print("员工删除成功！")

# 更新员工信息
def update_employee(emp_id, name, salary):
    update_employee_query = ("UPDATE employees "
                             "SET name = %s, salary = %s "
                             "WHERE emp_id = %s")
    data = (name, salary, emp_id)
    cursor.execute(update_employee_query, data)
    cnx.commit()
    print("员工信息更新成功！")

# 查询员工信息
def query_employee(emp_id):
    query_employee_query = ("SELECT * FROM employees "
                            "WHERE emp_id = %s")
    data = (emp_id,)
    cursor.execute(query_employee_query, data)
    result = cursor.fetchone()
    if result:
        print("员工信息如下：")
        print(f"员工编号：{result[0]}")
        print(f"员工姓名：{result[1]}")
        print(f"员工薪资：{result[2]}")
    else:
        print("没有找到该员工！")

# 关闭数据库连接
def close_connection():
    cursor.close()
    cnx.close()

# 测试代码
if __name__ == '__main__':
    add_employee(1, '张三', 10000)
    add_employee(2, '李四', 12000)
    query_employee(1)
    query_employee(2)
    update_employee(1, '王五', 15000)
    delete_employee(2)
    query_employee(1)
    query_employee(2)
    close_connection()

在上面的代码中，我们定义了四个函数来实现增删改查操作，然后在 `if __name__ == '__main__':` 块中进行了测试。你可以根据自己的需求进行修改和扩展。