python中基于mysql数据库银行转账功能的实现

代码描述:
银行转账:
银行卡号:
金额：

import pymysql

class TransferMoney(object):
# 构造方法
def __init__(self, conn):
self.conn = conn
self.cur = conn.cursor()

def transfer(self, source_id, target_id, money):
# 1). 判断两个银行卡号是否存在?
# 2). 判断source_id是否有足够的钱？
# 3). source_id扣钱
# 4). target_id加钱
if not self.check_account_avaialbe(source_id):
raise  Exception("账户不存在")
if not self.check_account_avaialbe(target_id):
raise  Exception("账户不存在")

if self.has_enough_money(source_id, money):
try:
self.reduce_money(source_id, money)
self.add_money(target_id, money)
except Exception as e:
print("转账失败:", e)
self.conn.rollback()
else:
self.conn.commit()
print("%s给%s转账%s金额成功" % (source_id, target_id, money))

def check_account_avaialbe(self, acc_id):
"""判断帐号是否存在， 传递的参数是银行卡号的id"""
select_sqli = "select * from bankData where id=%d;" % (acc_id)
print("execute sql:", select_sqli)
res_count = self.cur.execute(select_sqli)
if res_count == 1:
return True
else:
# raise  Exception("账户%s不存在" %(acc_id))
return False

def has_enough_money(self, acc_id, money):
"""判断acc_id账户上金额> money"""
# 查找acc_id存储金额?
select_sqli = "select money from bankData where id=%d;" % (acc_id)
print("execute sql:", select_sqli)
self.cur.execute(select_sqli)  # ((1, 500), )

# 获取查询到的金额钱数;
acc_money = self.cur.fetchone()[0]
# 判断
if acc_money >= money:
return True
else:
return False

def add_money(self, acc_id, money):
update_sqli = "update bankData set money=money+%d  where id=%d" % (money, acc_id)
print("add money:", update_sqli)
self.cur.execute(update_sqli)

def reduce_money(self, acc_id, money):
update_sqli = "update bankData set money=money-%d  where id=%d" % (money, acc_id)
print("reduce money:", update_sqli)
self.cur.execute(update_sqli)

# 析构方法
def __del__(self):
self.cur.close()
self.conn.close()

if __name__ == '__main__':
# 1. 连接数据库，
conn = pymysql.connect(
host='localhost',
user='root',
password='redhat',
db='helloTest',
charset='utf8',
autocommit=True,    # 如果插入数据，， 是否自动提交? 和conn.commit()功能一致。
)
trans = TransferMoney(conn)
# assert trans.check_account_avaialbe(14255632) == False
# assert  trans.check_account_avaialbe(13997) == True
#
#
# assert  trans.has_enough_money(13997, 800) == False
# assert  trans.has_enough_money(13998, 700) == True
# trans.add_money(13998, 200)
# trans.reduce_money(13998, 200)
# # trans.transfer(12567, 16787, 100)
# trans.transfer(13997, 13998, 200)