python实现的MySQL增删改查操作实例小结

Python  /  管理员 发布于 7年前   180

本文实例总结了python实现的MySQL增删改查操作。分享给大家供大家参考，具体如下：

代码片段一

连接并执行sql

#encoding:UTF-8import MySQLdbconn = MySQLdb.Connect(  host = '127.0.0.1',  port = 3306,  user = 'root',  passwd='123456',  db='imooc',  charset='utf8')cursor = conn.cursor()print connprint cursorsql = "select * from user"cursor.execute(sql) #执行

取数据

print cursor.rowcount#取数据#fetchone()获取一条数据#fetchany(3)获取多条#fetchall()#获取客户缓冲区的所有数据# rs = cursor.fetchone()# print rs## rs = cursor.fetchmany(2)# print rs## rs = cursor.fetchall()# print rs# rs = cursor.fetchall()# for row in rs:#   print "userid=%s,username=%s" % row

更新数据库

# sql_insert = "insert into user(userid,username) values(10,'name10')"# sql_update = "update user set username='name91' where userid=9"# sql_delete = "delete from user where userid<3"# cursor.execute(sql_insert)# cursor.execute(sql_update)# cursor.execute(sql_delete)# #执行完后提交# conn.commit()# #发生异常时回滚# try:#   sql_insert = "insert into user(userid,username) values(10,'name10')"#   sql_update = "update user set username='name91' where userid=9"#   sql_delete = "delete from user where userid<3"#   cursor.execute(sql_insert)#   cursor.execute(sql_update)#   cursor.execute(sql_delete)#   conn.commit()# except Exception as e:#   print e#   conn.rollback()cursor.close()conn.close()

代码片段2 银行实例

#coding:UTF-8import sysimport MySQLdbclass TransferMoney(object):  def __init__(self,conn):    self.conn = conn  def tranfer(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 as e:      self.conn.rollback()      raise e  def check_acct_available(self, acctid):    cursor = self.conn.cursor()    try:      sql = "select * from account where acctid=%s"%acctid      cursor.execute(sql)      rs = cursor.fetchall()      if len(rs)!=1:        raise Exception("账号%s不存在"%acctid)    finally:      cursor.close()  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("账号%s没有足够的钱" % acctid)    finally:      cursor.close()  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("账号%s减款失败" % acctid)    finally:      cursor.close()  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 "reduce_money:" + sql      if cursor.rowcount != 1:        raise Exception("账号%s加款失败" % acctid)    finally:      cursor.close()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='123456',    db='imooc',    charset='utf8'  )  tr_money = TransferMoney(conn)  try:    tr_money.tranfer(source_acctid,target_acctid,money)  except Exception as e:    print "出现问题了" + str(e)  finally:    conn.close()

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