python3 操作MYSQL实例及异常信息处理--用traceback模块

# 用traceback模块查看异常
import traceback import pymysql db = pymysql.connect(host='localhost', user='root', password='root', port=3306, db='spiders') cursor = db.cursor() try: sql = 'SELECT graph, brand_name FROM base_info'
    # 执行sql语句 
 cursor.execute(sql) result = cursor.fetchone() except: 
    # 输出异常信息 
 traceback.print_exc() # 如果发生异常，则回滚 
 db.rollback() finally: # 最终关闭数据库连接 
    db.close()