python 连接操作 各类数据库（python培训）

python 连接操作 各类数据库（python培训）

摘要：

用Python写脚本也有一段时间了，经常操作数据库（MySQL），现在就整理下对各类数据库的操作，如后面有新的参数会补进来，慢慢完善。

一，python 操作 MySQL:详情见：​​这里​​

mac 安装： 再  sudo python setup.py build

【apt-get install python-mysqldb】

【yum install python-devel  & pip install MySQL-python】

【yum install python-devel mysql-devel & pip install mysql-python】

#!/bin/env python# -*- encoding: utf-8 -*-#-------------------------------------------------------------------------------# Purpose: example for python_to_mysql# Author: zhoujy# Created: 2013-06-14# update: 2013-06-14#-------------------------------------------------------------------------------import MySQLdbimport os#建立和数据库系统的连接，格式#conn = MySQLdb.connect(host='localhost',user='root',passwd='123456',db='test',port=3306,charset='utf8')#指定配置文件，确定目录,或则写绝对路径cwd = os.path.realpath(os.path.dirname(__file__))db_conf = os.path.join(cwd, 'db.conf')conn = MySQLdb.connect(read_default_file=db_conf,host='localhost',db='test',port=3306,charset='utf8')#要执行的sql语句query = 'select id from t1'#获取操作游标cursor = conn.cursor()#执行SQLcursor.execute(query)#获取一条记录,每条记录做为一个元组返回,返回3，游标指到第2条记录。result1 = cursor.fetchone()for i in result1: print i#返回影响的行数 print cursor.rowcount#获取指定数量记录,每条记录做为一个元组返回,返回1，2，游标从第2条记录开始，游标指到第4条记录。result2 = cursor.fetchmany(2)for i in result2: for ii in i: print ii#获取所有记录,每条记录做为一个元组返回,返回3，4，7，6,游标从第4条记录开始到最后。result3 = cursor.fetchall()for i in result3: for ii in i: print ii#获取所有记录,每条记录做为一个元组返回,返回3，4，7，6,游标从第1条记录开始#重置游标位置，0为偏移量，mode＝absolute | relative,默认为relativecursor.scroll(0,mode='absolute')result3 = cursor.fetchall()for i in result3: for ii in i: print ii#以下2种方法都可以把数据插入数据库：#(one)for i in range (10,20): query2 = 'insert into t1 values("%d",now())' %i cursor.execute(query2) #提交 conn.rollback()#(two)rows = []for i in range (10,20): rows.append(i)query2 = 'insert into t1 values("%s",now())'#executemany 2个参数,第2个参数是变量。cursor.executemany(query2,rows)#提交conn.commit()#选择数据库query3 = 'select id from dba_hospital'#重新选择数据库conn.select_db('chushihua')cursor.execute(query3)result4 = cursor.fetchall()for i in result4: for ii in i: print ii#不定义query，直接执行：cursor.execute("set session binlog_format='mixed'")#关闭游标，释放资源cursor.close()'''+------+---------------------+| id | modifyT |+------+---------------------+| 3 | 2010-01-01 00:00:00 || 1 | 2010-01-01 00:00:00 || 2 | 2010-01-01 00:00:00 || 3 | 2010-01-01 00:00:00 || 4 | 2013-06-04 17:04:54 || 7 | 2013-06-04 17:05:36 || 6 | 2013-06-04 17:05:17 |+------+---------------------+'''

注意：在脚本中，密码写在脚本里面很容易暴露，这样可以用一个配置文件的方式来存密码，如db.conf：

[client]user=rootpassword=123456

二，python 操作 MongoDB:详情见​​这里​​​和​​这里​​​以及​​这里​​

#!/bin/env python# -*- encoding: utf-8 -*-#-------------------------------------------------------------------------------# Purpose: example for python_to_mongodb# Author: zhoujy# Created: 2013-06-14# update: 2013-06-14#-------------------------------------------------------------------------------import pymongoimport os#建立和数据库系统的连接,创建Connection时，指定host及port参数conn = pymongo.Connection(host='127.0.0.1',port=27017)#admin 数据库有帐号，连接-认证-切换库db_auth = conn.admindb_auth.authenticate('sa','sa')#连接数据库db = conn.abc#连接表collection = db.stu#查看全部表名称db.collection_names()#print db.collection_names()#访问表的数据，指定列item = collection.find({},{"sname":1,"course":1,"_id":0})for rows in item: print rows.values()#访问表的一行数据print collection.find_one()#得到所有的列for rows in collection.find_one(): print rows#插入collection.insert({"sno":100,"sname":"jl","course":{"D":80,"S":85}})#或u = dict(sno=102,sname='zjjj',course={"D":80,"S":85})collection.insert(u)#得到行数print collection.find().count()print collection.find({"sno":100})#排序，按照某一列的值。pymongo.DESCENDING:倒序；pymongo.ASCENDING:升序。按照sno倒序item = collection.find().sort('sno',pymongo.DESCENDING) for rows in item: print rows.values()#多列排序item = collection.find().sort([('sno',pymongo.DESCENDING),('A',pymongo.ASCENDING)])#更新，第一个参数是条件，第二个参数是更新操作，$set,%inc,$push,$ne,$addToSet,$rename 等collection.update({"sno":100},{"$set":{"sno":101}})#更新多行和多列collection.update({"sno":102},{"$set":{"sno":105,"sname":"SSSS"}},multi=True)#删除，第一个参数是条件，第二个参数是删除操作。collection.remove({"sno":101})'''sno:学号；sname：姓名；course：科目db.stu.insert({"sno":1,"sname":"张三","course":{"A":95,"B":90,"C":65,"D":74,"E":100}})db.stu.insert({"sno":2,"sname":"李四","course":{"A":90,"B":85,"X":75,"Y":64,"Z":95}})db.stu.insert({"sno":3,"sname":"赵五","course":{"A":70,"B":56,"F":85,"G":84,"H":80}})db.stu.insert({"sno":4,"sname":"zhoujy","course":{"A":64,"B":60,"C":95,"T":94,"Y":85}})db.stu.insert({"sno":5,"sname":"abc","course":{"A":87,"B":70,"Z":56,"G":54,"H":75}})db.stu.insert({"sno":6,"sname":"杨六","course":{"A":65,"U":80,"C":78,"R":75,"N":90}})db.stu.insert({"sno":7,"sname":"陈二","course":{"A":95,"M":68,"N":84,"S":79,"K":89}})db.stu.insert({"sno":8,"sname":"zhoujj","course":{"P":90,"B":77,"J":85,"K":68,"L":80}})db.stu.insert({"sno":9,"sname":"ccc","course":{"Q":85,"B":86,"C":90,"V":87,"U":85}})'''

计算Mongodb文档中各集合的数目：

import pymongoconn = pymongo.Connection(host='127.0.0.1',port=27017)db = conn.abc #abc文档for tb_name in db.collection_names(): #循环出各集合名 Count = db[tb_name].count() #计算各集合的数量 if Count > 2: #过滤条件 print tb_name + ':' + str(Count) '''conn = pymongo.Connection(host='127.0.0.1',port=27017)db = conn.abcfor tb_name in db.collection_names(): print tb_name + ':' exec('print ' + 'db.'+tb_name+'.count()') #变量当集合的处理方式ORconn = pymongo.Connection(host='127.0.0.1',port=27017)db = conn.abcfor tb_name in db.collection_names(): mon_dic=db.command("collStats", tb_name) #以字典形式返回 print mon_dic.get('ns'),mon_dic.get('count')'''

updatetime: 2015-06-30

MongoDB升级到了3.0之后，用python的连接会出错：

pymongo.errors.OperationFailure: command SON([('authenticate', 1), ('user', u'dba'), ('nonce', u'8c7842b068e14d3'), ('key', u'584ec63f1cdfd8525ce33d99cd269c2c')]) failed: auth failed

表示认证失败，说明MongoDB升级之后，对用用户的加密方式改变了。那就升级pymongo。

zhoujy@zhoujy:~$ sudo pip install pymongo --upgrade[sudo] password for zhoujy:......Successfully installed pymongoCleaning up...

升级成功，要是没有安装pip，看这里：​​sudo apt-get install python-pip python-dev build-essential $ sudo pip install --upgrade pip $ sudo pip install --upgrade virtualenv

ubuntu10.10之前的老版本：

$ sudo apt-get install python-setuptools python-dev build-essential $ sudo easy_install pip $ sudo pip install --upgrade virtualenv

升级成功之后，继续执行python脚本，还是出错：

AttributeError: 'module' object has no attribute 'Connection'

表示没有 Connection ，pymongo升级完之后不支持了，看​​手册​​，发现用MongoClient 来替换了Connection。修改脚本：

conn = pymongo.Connection(host='127.0.0.1',port=27017)改成conn = pymongo.MongoClient(host='127.0.0.1',port=27017)

最后执行python，正常。

三，python 操作 Redis:详情见​​这里​​ 和 ​​这里​​/​​这里​​；​​集群连接​​

#!/bin/env python# -*- encoding: utf-8 -*-#-------------------------------------------------------------------------------# Purpose: example for python_to_mongodb# Author: zhoujy# Created: 2013-06-14# update: 2013-06-14#-------------------------------------------------------------------------------import redisf = open('aa.txt')while True: line = f.readline().strip().split(' # ') if line == ['']: break UserName,Pwd,Email = line# print name.strip(),pwd.strip(),email.strip() rc = redis.StrictRedis(host='127.0.0.1',port=6379,db=15) rc.hset('Name:' + UserName,'Email',Email) rc.hset('Name:' + UserName,'Password',Pwd)f.close()alluser = rc.keys('*')#print alluserprint "===================================读出存进去的数据==================================="for user in alluser: print ' # '.join((user.split(':')[1],rc.hget(user,'Password'),rc.hget(user,'Email')))

一个pipeline的请看：这里

四，python 操作 memcache:详情见 这里​ 和 ​​这里​​

import memcachemc = memcache.Client(['127.0.0.1:11211'],debug=1)

#!/usr/bin/env python#coding=utf-8import MySQLdbimport memcacheimport sysimport timedef get_data(mysql_conn):# nn = raw_input("press string name:") mc = memcache.Client(['127.0.0.1:11211'],debug=1) t1 =time.time() value = mc.get('zhoujinyia') if value == None: t1 = time.time() print t1 query = "select company,email,sex,address from uc_user_offline where realName = 'zhoujinyia'" cursor= mysql_conn.cursor() cursor.execute(query) item = cursor.fetchone() t2 = time.time() print t2 t = round(t2-t1) print "from mysql cost %s sec" %t print item mc.set('zhoujinyia',item,60) else : t2 = time.time() t=round(t2-t1) print "from memcache cost %s sec" %t print valueif __name__ =='__main__': mysql_conn = MySQLdb.connect(host='127.0.0.1',user='root',passwd='123456',db='member',port=3306,charset='utf8') get_data(mysql_conn)

上面介绍了一些python连接数据库，红色部分是连接操作的关键部分，大部分的操作没有列出来，具体的请见各官网。

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