python如何实现事务机制

def transaction_test():

"""

事务演示

"""

conn, cursor = get_conn('testdb')

sql = "delete from employee where age > %s" % (20)

try:

   # 执行SQL语句

   cursor.execute(sql)

   # 这里以除0异常，来演示现实场景

   n = 1 / 0

   # 向数据库提交

   conn.commit()

except:

   # 发生错误时回滚

   print('事务回滚')

   conn.rollback()

cursor.close()

conn.close()