python实现的MySQL增删改查操作实例小结
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-8 import MySQLdb conn = MySQLdb.Connect( host = '127.0.0.1', port = 3306, user = 'root', passwd='123456', db='imooc', charset='utf8' ) cursor = conn.cursor() print conn print cursor sql = "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-8
import sys
import MySQLdb
class 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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