CREATE TABLE `account` (
`acctid` int(11) DEFAULT NULL COMMENT '账户ID',
`money` int(11) DEFAULT NULL COMMENT '余额'
) ENGINE=InnoDB DEFAULT CHARSET=utf8
# coding:utf8 import MySQLdb
import sys class TransferMoney(object):
"""docstring for TransferMoney"""
def __init__(self, conn):
self.conn = conn def check_acct_avaiable(self,acctid):
cursor = self.conn.cursor()
try:
sql = "select * from account where acctid = %s" % acctid
cursor.execute(sql)
print "check_acct_avaiable:" + sql
rs = cursor.fetchall()
if len(rs) != 1:
raise Exception("账号%s不存在" % acctid)
finally:
cursor.close() 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("账号%s没有足够的钱" % acctid)
finally:
cursor.close() 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("账号%s减款失败" % acctid)
finally:
cursor.close() 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("账号%s加款失败" % acctid)
finally:
cursor.close() 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, 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 = 'njczy2010',
passwd = '',
db = 'czy',
charset = 'utf8'
) tr_money = TransferMoney(conn) try:
tr_money.transfer(source_acctid,target_acctid,money)
except Exception as e:
print "出现问题 " + str(e)
finally:
conn.close()
正确情况：
check_acct_avaiable:select * from account where acctid = 11
check_acct_avaiable:select * from account where acctid = 12
has_enough_money:select * from account where acctid = 11 and money > 100
reduce_money:update account set money = money - 100 where acctid = 11
add_money:update account set money = money + 100 where acctid = 12
错误情况：
check_acct_avaiable:select * from account where acctid = 11
check_acct_avaiable:select * from account where acctid = 12
has_enough_money:select * from account where acctid = 11 and money > 100
出现问题 账号11没有足够的钱