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python实现的MySQL增删改查操作实例小结

2019-01-06 00:03 836 查看

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()

更多关于Python相关内容感兴趣的读者可查看本站专题：《Python+MySQL数据库程序设计入门教程》、《Python常见数据库操作技巧汇总》、《Python数学运算技巧总结》、《Python数据结构与算法教程》、《Python函数使用技巧总结》、《Python字符串操作技巧汇总》、《Python入门与进阶经典教程》及《Python文件与目录操作技巧汇总》

希望本文所述对大家Python程序设计有所帮助。

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