SQL基本語法 - Python版：
db = MySQLdb.connect(host="localhost", user="root", passwd="5796857968", db="OVS")
cursor = db.cursor()#Create instance to access DB
1. update
cursor.execute("update OVS.check_cv_Info set packets_now=%s,status=%s where subnet=%s and subnet_section=%s", [ n_packets[i], "1" ,db_value[j][0] ,db_value[j][1] ] )
db.commit()
2. select
cursor.execute("SELECT packets_now From check_cv_Info WHERE subnet=%s", [ get_subnet[i] ]) #15
packets_rownu = cursor.rowcount #rows number
packets = cursor.fetchall()
3. insert
cursor.execute("INSERT INTO Pica8_Switch_Help(FK, Help_Nu) VALUES(%s,%s)", [ str( int(j)+1 ), str( int(dead_switch[i])+1 ) ] ) #Update to DB, +1 in order to 'Nu' field
db.commit()
4. delete
cursor.execute("DELETE FROM OVS.check_cv_Info")
db.commit()
