【python-mysql】| 银行转账案例代码

#!/usr/bin/env python
# coding:utf-8

"""
@Name: mysql_01.py
@Author: lvah
@Date:2/28/18
@Connect: [email protected]
@Desc:

    银行转账的数据库实现;


"""

print "mysql_01.py代码结果展示:"

import sys
import MySQLdb as mysql


# 抽象出一个转账的类；
class TransferMoney(object):
    def __init__(self, conn):
        self.conn = conn

    def transfer(self, source_acctid, target_acctid, money):
        try:
            self.check_acct_available(source_acctid)
            self.check_acct_available(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

    def check_acct_available(self, acct_id):
        cursor = self.conn.cursor()
        try:
            sql = "select * from account where acctid=%s" % (acct_id)
            cursor.execute(sql)
            print "check_acct_available:" + sql
            rs = cursor.fetchall()
            if len(rs) != 1:
                raise Exception("帐号%s不存在" % acct_id)
        finally:
            cursor.close()

    def has_enough_money(self, acct_id, money):
        cursor = self.conn.cursor()
        try:
            sql = "select * from account where acctid=%s and money > %s" % (acct_id, money)
            cursor.execute(sql)
            print "has_enough_money:" + sql
            rs = cursor.fetchall()
            if len(rs) != 1:
                raise Exception("帐号%s没有足够的钱" % acct_id)
        finally:
            cursor.close()


    def reduce_money(self, acct_id, money):
        cursor = self.conn.cursor()
        try:
            sql = "update account set money=money-%s where acctid=%s" % (money, acct_id)
            cursor.execute(sql)
            print "reduce_money:" + sql
            if cursor.rowcount != 1:
                raise Exception("帐号%s减款失败" % acct_id)
        finally:
            cursor.close()
    def add_money(self, acct_id, money):
        cursor = self.conn.cursor()
        try:
            sql = "update account set money=money+%s where acctid=%s" % (money, acct_id)
            cursor.execute(sql)
            print "reduce_money:" + sql
            if cursor.rowcount != 1:
                raise Exception("帐号%s加款失败" % acct_id)
        finally:
            cursor.close()


if __name__ == "__main__":
    # source_acctid = sys.argv[1]
    # target_acctid = sys.argv[2]
    # money = sys.argv[3]


    source_acctid = 2
    target_acctid = 1
    money = 100

    conn = mysql.connect(host='localhost', user='root', passwd='westos', db='bank_data')
    tr_money = TransferMoney(conn)

    try:
        tr_money.transfer(source_acctid, target_acctid, money)
    except Exception, e:
        print "出现问题:" + str(e)
    finally:
        conn.close()