Python 学习笔记 - 操作MySQL
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Python里面操作MySQL可以通过两个方式:
pymysql模块
ORM框架的SQLAchemey
本节先学习第一种方式。
学习Python模块之前,首先看看MySQL的基本安装和使用,具体语法可以参考豆子之前的博客http://beanxyz.blog.51cto.com/5570417/1609972
或者官方简介
https://mariadb.com/kb/en/mariadb/basic-sql-statements/
简单的回顾一下基本环境的搭建:
首先安装Mariadb(我的环境是CentOS7)
yum install mariadb* systemctl start mariadb
配置防火墙
firewall-cmd --add-port=3306/tcp --permanent systemctl restart firewalld
配置root密码
mysqladmin -u root password ‘mysql‘ mysql -uroot -p
创建一个测试用的数据库和表
MariaDB [(none)]> create database mydb; Query OK, 1 row affected (0.00 sec) MariaDB [(none)]> use mydb Database changed MariaDB [mydb]> create table student(id int not null auto_increment,name varchar(10), primary key(id)); Query OK, 0 rows affected (0.04 sec) MariaDB [mydb]> insert into student(name) values(‘Jay‘),(‘Bob‘),(‘Alex‘); Query OK, 3 rows affected (0.00 sec) Records: 3 Duplicates: 0 Warnings: 0 MariaDB [mydb]> select * from student; +----+------+ | id | name | +----+------+ | 1 | Jay | | 2 | Bob | | 3 | Alex | +----+------+ 3 rows in set (0.00 sec)
创建一个远程访问的账户
MariaDB [(none)]> create user [email protected]; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> set password for [email protected]‘10.2.100.60‘=password(‘yli‘); Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> grant all privileges on mydb.* to [email protected]; Query OK, 0 rows affected (0.00 sec)
然后安装一个图形界面的工具Navicat,绑定数据库
这样一个基本的测试环境就搭建好了。
现在来看看pymysql的使用。
在我的客户端安装一下pymysql的模块
C:\WINDOWS\system32>pip install pymysql Collecting pymysql Downloading PyMySQL-0.7.9-py3-none-any.whl (78kB) 100% |################################| 81kB 610kB/s Installing collected packages: pymysql Successfully installed pymysql-0.7.9
Python源码演示
查询
#!/usr/bin/env python # -*- coding:utf-8 -*- import pymysql #打开数据库连接 conn = pymysql.connect(host=‘sydnagios‘, port=3306, user=‘yli‘, passwd=‘yli‘, db=‘mydb‘) #创建一个游标对象 cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) #SQL查询 cursor.execute("select * from student") # 获取第一行数据 # row_1 = cursor.fetchone() # print(row_1) # 获取前n行数据 # row_2 = cursor.fetchmany(3) # 获取所有数据 row_3 = cursor.fetchall() print(row_3) #scroll可以使用相对位置或者绝对位置,这里相对位置(末尾)向上移动2行 cursor.scroll(-2,mode=‘relative‘) row_3 = cursor.fetchall() print(row_3) #提交,不然无法保存新的数据 conn.commit() #关闭游标 cursor.close() #关闭连接 conn.close() ----------- [{‘id‘: 1, ‘name‘: ‘Jay‘}, {‘id‘: 2, ‘name‘: ‘Bob‘}, {‘id‘: 3, ‘name‘: ‘Alex‘}] [{‘id‘: 2, ‘name‘: ‘Bob‘}, {‘id‘: 3, ‘name‘: ‘Alex‘}]
修改
#!/usr/bin/env python # -*- coding:utf-8 -*- import pymysql conn = pymysql.connect(host=‘sydnagios‘, port=3306, user=‘yli‘, passwd=‘yli‘, db=‘mydb‘) cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) cursor.execute("Update student set name=‘BoB‘ where id=2") cursor.execute("select * from student") row_3 = cursor.fetchall() print(row_3) conn.commit() cursor.close() conn.close() ---------- [{‘id‘: 1, ‘name‘: ‘Chris‘}, {‘id‘: 2, ‘name‘: ‘BoB‘}, {‘id‘: 3, ‘name‘: ‘Alex‘}]
删除
#!/usr/bin/env python # -*- coding:utf-8 -*- import pymysql conn = pymysql.connect(host=‘sydnagios‘, port=3306, user=‘yli‘, passwd=‘yli‘, db=‘mydb‘) cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) cursor.execute("delete from student where id=2") cursor.execute("select * from student") row_3 = cursor.fetchall() print(row_3) conn.commit() cursor.close() conn.close() ---------- [{‘id‘: 1, ‘name‘: ‘Chris‘}, {‘id‘: 2, ‘name‘: ‘BoB‘}, {‘id‘: 3, ‘name‘: ‘Alex‘}]
添加
#!/usr/bin/env python # -*- coding:utf-8 -*- import pymysql conn = pymysql.connect(host=‘sydnagios‘, port=3306, user=‘yli‘, passwd=‘yli‘, db=‘mydb‘) cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) cursor.execute("insert into student(name) value (‘ZhangSan‘),(‘LiSi‘)") cursor.execute("select * from student") row_3 = cursor.fetchall() print(row_3) conn.commit() cursor.close() conn.close() ---------- [{‘name‘: ‘Chris‘, ‘id‘: 1}, {‘name‘: ‘Alex‘, ‘id‘: 3}, {‘name‘: ‘ZhangSan‘, ‘id‘: 4}, {‘name‘: ‘LiSi‘, ‘id‘: 5}]
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