请用python3.0编写一段代码能连接oracle，每天定时从一个一个库抽取数据插入另一个库

import cx_Oracle
import datetime conn = cx_Oracle.connect('username/password@host:port/database')
c = conn.cursor() #获取当前时间
now = datetime.datetime.now() #定义源数据库
source_db = 'source_db' #定义目标数据库
target_db = 'target_db' #定义插入SQL
insert_sql = 'INSERT INTO {} VALUES(:1, :2, :3)'.format(target_db) #定义查询SQL
select_sql = 'SELECT * FROM {} WHERE time > :1'.format(source_db) #每次抽取的数据量
num = 1000
while(True):
#查询数据
c.execute(select_sql, (now - datetime.timedelta(minutes=5),)) #插入数据
c.executemany(insert_sql, c.fetchmany(num))
conn.commit() #更新当前时间
now = datetime.datetime.now()