Python实现完整的事务操作示例

本文实例讲述了Python事务操作实现方法。分享给大家供大家参考，具体如下：

#coding=utf-8
import sys
import MySQLdb
class TransferMoney(object):
 def __init__(self,conn):
   self.conn = conn
 #检查账户是否合法
 def check_acct_avaiable(self,acctid):
   cursor = self.conn.cursor()
   try:
     sql = "select * from account where acctid=％s" ％ acctid
     cursor.execute(sql)
     print "check account:" + sql
     rs = cursor.fetchall()
     if len(rs) != 1:
       raise Exception("account ％s illega" ％ acctid)
   finally:
     cursor.close()
 #检查是否有足够的钱
 def has_enough_money(self,acctid,money):
   cursor = self.conn.cursor()
   try:
     sql = "select * from account where acctid=％s and money > ％s" ％ (acctid,money)
     cursor.execute(sql)
     print "has enough money:" + sql
     rs = cursor.fetchall()
     if len(rs) != 1:
       raise Exception("account ％s not enough money" ％ acctid)
   finally:
     cursor.close()
 #账户减钱
 def reduce_money(self,acctid,money):
   cursor = self.conn.cursor()
   try:
     sql = "update account set money = money-％s where acctid = ％s" ％ (money,acctid)
     cursor.execute(sql)
     print "reduce_money:" + sql
     if cursor.rowcount != 1:
       raise Exception("reduce money fail ％s" ％ acctid)
   finally:
     cursor.close()
 #账户加钱
 def add_money(self,acctid,money):
   cursor = self.conn.cursor()
   try:
     sql = "update account set money = money+％s where acctid = ％s" ％ (money,acctid)
     cursor.execute(sql)
     print "add_money:" + sql
     if cursor.rowcount != 1:
       raise Exception("add money fail ％s" ％ acctid)
   finally:
     cursor.close()
 #主执行语句
 def transfer(self,source_acctid,target_acctid,money):
   try:
     self.check_acct_avaiable(source_acctid)
     self.check_acct_avaiable(target_acctid)
     self.has_enough_money(source_acctid,money)
     self.reduce_money(source_acctid,money)
     self.add_money(target_acctid,money)
     self.conn.commit()
   except Exception as e:
     self.conn.rollback()
     raise e
if __name__ == "__main__":
 source_acctid = sys.argv[1]
 target_acctid = sys.argv[2]
 money = sys.argv[3]
 conn = MySQLdb.Connect(host = '127.0.0.1',port=3306,user='root',passwd='',db='test',charset='utf8')
 tr_money = TransferMoney(conn)
 try:
   tr_money.transfer(source_acctid,target_acctid,money)
 except Exception as e:
   print "Happen:" + str(e)
 finally:
   conn.close()

希望本文所述对大家Python程序设计有所帮助。