python一套完整的事务操作
2015-08-30 22:01
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#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()
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