python操作數據之更新數據庫

import pymysql
def update(sql):
    """
    更新數據
    """
    con = pymysql.connect(
        host="********",
        port=3306,
        user="root",
        password="******",
        database="******",
        charset='utf8'
    )  # 鏈接數據庫
    cur = con.cursor() # 獲取游標
    cur.execute(sql)
    con.commit() # 提交數據
    cur.close() # 關閉游標
    con.close() # 關閉鏈接
if __name__=='__main__':
    sql = "update plan set instance='*******' where id = 4"
    update(sql)