Python操作MySQL模拟银行转账
今天在慕课网上学习了有关于python操作MySQL的相关知识，在此做些总结。python操作数据库还是相对比较简单的，由于python统一了各个数据库的接口程序，也就是所谓的Python DB，所以无论使用何种数据可，都可以用统一的接口对数据库进行操作。操作中主要涉及connection对象的操作和cursor的操作，前者主要是为了建立起python与数据库的数据交换通道，后者则是访问数据的游标，也可以理解为指针。数据库的相关结构化语言在Python中均是以字符串的形式呈现的。另外注意rollback的重要性，一旦操作失败，所有操作都要回滚到之前的状态，否则会发生错误。
另外，在编写实例的时候，对于面向对象的编程思路又有了新的认识，自顶向下的程序编写模式非常有利于拆分程序的功能，分而治之。面向对象的封装性在此提醒的淋漓尽致！
代码如下，在原有基础上，我又增加了添加记录的功能。
#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错误！")
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("余额不足！")
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('减款失败！')
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('加款失败！')
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 "转账错误"+str(e)
try:
trMoney.createNewUser(newID,newmoney)
except Exception as e:
print "创建用户失败！"+str(e)
finally:
conn.close()
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持【听图阁-专注于Python设计】。
