Python操作MySQL模擬銀行轉(zhuǎn)賬

發(fā)布時(shí)間：2020-09-04 17:47:29 來(lái)源：腳本之家閱讀：252 作者：freedom098 欄目：開(kāi)發(fā)技術(shù)

今天在慕課網(wǎng)上學(xué)習(xí)了有關(guān)于python操作MySQL的相關(guān)知識(shí)，在此做些總結(jié)。python操作數(shù)據(jù)庫(kù)還是相對(duì)比較簡(jiǎn)單的，由于python統(tǒng)一了各個(gè)數(shù)據(jù)庫(kù)的接口程序，也就是所謂的Python DB，所以無(wú)論使用何種數(shù)據(jù)可，都可以用統(tǒng)一的接口對(duì)數(shù)據(jù)庫(kù)進(jìn)行操作。操作中主要涉及connection對(duì)象的操作和cursor的操作，前者主要是為了建立起python與數(shù)據(jù)庫(kù)的數(shù)據(jù)交換通道，后者則是訪問(wèn)數(shù)據(jù)的游標(biāo)，也可以理解為指針。數(shù)據(jù)庫(kù)的相關(guān)結(jié)構(gòu)化語(yǔ)言在Python中均是以字符串的形式呈現(xiàn)的。另外注意rollback的重要性，一旦操作失敗，所有操作都要回滾到之前的狀態(tài)，否則會(huì)發(fā)生錯(cuò)誤。

另外，在編寫(xiě)實(shí)例的時(shí)候，對(duì)于面向?qū)ο蟮木幊趟悸酚钟辛诵碌恼J(rèn)識(shí)，自頂向下的程序編寫(xiě)模式非常有利于拆分程序的功能，分而治之。面向?qū)ο蟮姆庋b性在此提醒的淋漓盡致！

代碼如下，在原有基礎(chǔ)上，我又增加了添加記錄的功能。

#coding=utf8 
import MySQLdb 
import sys 
 
class TranseferMonet(object): 
 
  def __init__(self,conn): 
    self.conn = conn 
 
  def createNewUser(self,userID,money): 
    cursor = self.conn.cursor() 
    try: 
      sql = 'INSERT account VALUES(%s,%s)' %(str(userID),str(money)) 
      cursor.execute(sql) 
      self.conn.commit() 
    except Exception as e: 
      self.conn.rollback() 
      raise e 
 
  def transferMoney(self,transeferID,recivierID,money): 
    try: 
      self.checkID(transeferID) 
      self.checkID(receiverID) 
      self.checkEnoughMoney(transferID,money) 
      self.subMoney(transferID,money) 
      self.addMoney(receiverID,money) 
      self.conn.commit() 
    except Exception as e: 
      self.conn.rollback() 
      raise e 
 
  def checkID(self,userID): 
    cursor = self.conn.cursor() 
    try: 
      sql = 'SELECT userID FROM account WHERE userID = %s' %str(userID) 
      cursor.execute(sql) 
      rs = cursor.fetchall() 
      if len(rs) != 1: 
        raise Exception("ID錯(cuò)誤！") 
    finally: 
      cursor.close() 
 
  def checkEnoughMoney(self,transferID,money): 
    cursor = self.conn.cursor() 
    try: 
      sql = 'SELECT money FROM account WHERE userID = %s and money >= %s' %(str(transferID),str(money)) 
      cursor.execute(sql) 
      rs = cursor.fetchall() 
      if len(rs) != 1: 
        raise Exception("余額不足！") 
    finally: 
      cursor.close() 
  def subMoney(self,transferID,money): 
    cursor = self.conn.cursor() 
    try: 
      sql = 'UPDATE account SET money = money-%s WHERE userID = %s' %(str(money),str(transferID)) 
      cursor.execute(sql) 
      if cursor.rowcount != 1: 
        raise Exception('減款失??！') 
    finally: 
      cursor.close() 
 
  def addMoney(self,receiverID,money): 
 
    cursor = self.conn.cursor() 
    try: 
      sql = 'UPDATE account SET money = money+%s WHERE userID = %s' %(str(money),str(receiverID)) 
      cursor.execute(sql) 
      if cursor.rowcount != 1: 
        raise Exception('加款失敗！') 
    finally: 
      cursor.close() 
 
if __name__=="__main__": 
 
  transferID = 2002 
  receiverID = 2001 
  money = 300 
 
  newID = 2003 
  newmoney = 900 
 
  conn = MySQLdb.connect(host = '127.0.0.1',port = 3306,user = 'root',passwd = '914767195',db = 'test',charset = 'utf8') 
 
  trMoney = TranseferMonet(conn) 
 
  try: 
    trMoney.transferMoney(transferID,receiverID,money) 
  except Exception as e: 
    print "轉(zhuǎn)賬錯(cuò)誤"+str(e) 
  try: 
    trMoney.createNewUser(newID,newmoney) 
  except Exception as e: 
    print "創(chuàng)建用戶(hù)失敗！"+str(e) 
  finally: 
    conn.close()

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持億速云。

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Python操作MySQL模擬銀行轉(zhuǎn)賬

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