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)