Python从数据库读取大量数据批量写入文件的方法

#%%import pymssql as MySQLdb #这里是python3 如果你是python2.x的话，import MySQLdb#数据库连接属性hst = '188.10.34.18'usr = 'sa'passwd = 'p@ssw0rd'db = 'HistoryTrace' #总共多少数据allData = 1674333#每个批次多少条数据dataOfEach = 20000#批次batch = ceil(allData/dataOfEach) #文件名global IDctrl IDctrl = 1filename = str(IDctrl)+'.txt' #连接数据库conn = MySQLdb.connect(host=hst,user=usr,password=passwd,database=db)cur=conn.cursor() while IDctrl<batch: #读取数据库 sql = 'SELECT Longitude,Latitude,Altitude,VelComOfLong,VelComOfLati,Aircraft,Section,TimeMinus/    FROM dealed1 where ID>=' + str(IDctrl) + ' and ID <' + str(IDctrl + dataOfEach)  cur.execute(sql) rows=cur.fetchall() #写文件 f = open(filename,'w') f.writelines(str(rows)) #文件名加1 IDctrl+=1 filename = str(IDctrl)+'.txt' #关闭数据库连接f.close()conn.close()