python之数据库操作

数据库操作

Python 操作 Mysql 模块的安装

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linux：     yum install MySQL-python   window：     http://files.cnblogs.com/files/wupeiqi/py-mysql-win.zip

SQL基本使用

1、数据库操作

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show databases; use [databasename]; create database  [name];

2、数据表操作

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show tables;   create table students     (         id int  not null auto_increment primary key,         name char(8) not null,         sex char(4) not null,         age tinyint unsigned not null,         tel char(13) null default "-"     );

 CREATE TABLE `wb_blog` (
     `id` smallint(8) unsigned NOT NULL,
     `catid` smallint(5) unsigned NOT NULL DEFAULT ',
     `title` varchar(80) NOT NULL DEFAULT '',
     `content` text NOT NULL,
     PRIMARY KEY (`id`),
     UNIQUE KEY `catename` (`catid`)
 ) ; 

创建表wb_blog

3、数据操作

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insert into students(name,sex,age,tel) values('alex','man',18,'151515151')   delete from students where id =2;   update students set name = 'sb' where id =1;   select * from students

4、其他

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主键 外键 左右连接

Python MySQL API

一、插入数据

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import MySQLdb    conn = MySQLdb.connect(host='127.0.0.1',user='root',passwd='1234',db='mydb')    cur = conn.cursor()    reCount = cur.execute('insert into UserInfo(Name,Address) values(%s,%s)',('alex','usa')) # reCount = cur.execute('insert into UserInfo(Name,Address) values(%(id)s, %(name)s)',{'id':12345,'name':'wupeiqi'})    conn.commit()    cur.close() conn.close()    print reCount

import MySQLdb

conn = MySQLdb.connect(host=',db='mydb')

cur = conn.cursor()

li =[
     ('alex','usa'),
     ('sb','usa'),
]
reCount = cur.executemany('insert into UserInfo(Name,Address) values(%s,%s)',li)

conn.commit()
cur.close()
conn.close()

print reCount

MySQLdb

注意：cur.lastrowid

二、删除数据

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import MySQLdb   conn = MySQLdb.connect(host='127.0.0.1',user='root',passwd='1234',db='mydb')   cur = conn.cursor()   reCount = cur.execute('delete from UserInfo')   conn.commit()   cur.close() conn.close()   print reCount

三、修改数据

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import MySQLdb   conn = MySQLdb.connect(host='127.0.0.1',user='root',passwd='1234',db='mydb')   cur = conn.cursor()   reCount = cur.execute('update UserInfo set Name = %s',('alin',))   conn.commit() cur.close() conn.close()   print reCount

四、查数据

# ############################## fetchone/fetchmany(num)  ##############################

import MySQLdb

conn = MySQLdb.connect(host='127.0.0.1',user='root',passwd='1234',db='mydb')
cur = conn.cursor()

reCount = cur.execute('select * from UserInfo')

print cur.fetchone()
print cur.fetchone()
cur.scroll(-1,mode='relative')
print cur.fetchone()
print cur.fetchone()
cur.scroll(0,mode='absolute')
print cur.fetchone()
print cur.fetchone()

cur.close()
conn.close()

print reCount

# ############################## fetchall  ##############################

import MySQLdb

conn = MySQLdb.connect(host='127.0.0.1',user='root',passwd='1234',db='mydb')
#cur = conn.cursor(cursorclass = MySQLdb.cursors.DictCursor)
cur = conn.cursor()

reCount = cur.execute('select Name,Address from UserInfo')

nRet = cur.fetchall()

cur.close()
conn.close()

print reCount
print nRet
for i in nRet:
    print i[0],i[1]