今天在慕課網上學習了有關于python操作MySQL的相關知識，在此做些總結。python操作數據庫還是相對比較簡單的，由于python統一了各個數據庫的接口程序，也就是所謂的Python DB，所以無論使用何種數據可，都可以用統一的接口對數據庫進行操作。操作中主要涉及connection對象的操作和cursor的操作，前者主要是為了建立起python與數據庫的數據交換通道，后者則是訪問數據的游標，也可以理解為指針。數據庫的相關結構化語言在Python中均是以字符串的形式呈現的。另外注意rollback的重要性，一旦操作失敗，所有操作都要回滾到之前的狀態，否則會發生錯誤。

另外，在編寫實例的時候，對于面向對象的編程思路又有了新的認識，自頂向下的程序編寫模式非常有利于拆分程序的功能，分而治之。面向對象的封裝性在此提醒的淋漓盡致！

代碼如下，在原有基礎上，我又增加了添加記錄的功能。

#coding=utf8 import MySQLdb import sys  class TranseferMonet(object):    def __init__(self,conn):     self.conn = conn    def createNewUser(self,userID,money):     cursor = self.conn.cursor()     try:       sql = 'INSERT account VALUES(%s,%s)' %(str(userID),str(money))       cursor.execute(sql)       self.conn.commit()     except Exception as e:       self.conn.rollback()       raise e    def transferMoney(self,transeferID,recivierID,money):     try:       self.checkID(transeferID)       self.checkID(receiverID)       self.checkEnoughMoney(transferID,money)       self.subMoney(transferID,money)       self.addMoney(receiverID,money)       self.conn.commit()     except Exception as e:       self.conn.rollback()       raise e    def checkID(self,userID):     cursor = self.conn.cursor()     try:       sql = 'SELECT userID FROM account WHERE userID = %s' %str(userID)       cursor.execute(sql)       rs = cursor.fetchall()       if len(rs) != 1:         raise Exception("ID錯誤！")     finally:       cursor.close()    def checkEnoughMoney(self,transferID,money):     cursor = self.conn.cursor()     try:       sql = 'SELECT money FROM account WHERE userID = %s and money >= %s' %(str(transferID),str(money))       cursor.execute(sql)       rs = cursor.fetchall()       if len(rs) != 1:         raise Exception("余額不足！")     finally:       cursor.close()   def subMoney(self,transferID,money):     cursor = self.conn.cursor()     try:       sql = 'UPDATE account SET money = money-%s WHERE userID = %s' %(str(money),str(transferID))       cursor.execute(sql)       if cursor.rowcount != 1:         raise Exception('減款失敗！')     finally:       cursor.close()    def addMoney(self,receiverID,money):      cursor = self.conn.cursor()     try:       sql = 'UPDATE account SET money = money+%s WHERE userID = %s' %(str(money),str(receiverID))       cursor.execute(sql)       if cursor.rowcount != 1:         raise Exception('加款失敗！')     finally:       cursor.close()  if __name__=="__main__":    transferID = 2002   receiverID = 2001   money = 300    newID = 2003   newmoney = 900    conn = MySQLdb.connect(host = '127.0.0.1',port = 3306,user = 'root',passwd = '914767195',db = 'test',charset = 'utf8')    trMoney = TranseferMonet(conn)    try:     trMoney.transferMoney(transferID,receiverID,money)   except Exception as e:     print "轉賬錯誤"+str(e)   try:     trMoney.createNewUser(newID,newmoney)   except Exception as e:     print "創建用戶失敗！"+str(e)   finally:     conn.close()