Python database operations

Installing MySQL-python under Windows

Download address: https://pypi.python.org/pypi/MySQL-python/1.2.5 Just install it into the system.

Install MySQL-python under linux to connect to MySQL:

Download address: https://pypi.python.org/pypi/MySQL-python/

After decompression, enter the directory and execute python setup.py install

Common problems encountered during the installation process:

1. Tips If mysql_config cannot be found, it is usually because mysql is installed using the lnmp one-click installation package. The path is

. Solution: locate mysql_config to find the location of the mysql_config file, and then ln -s to make a soft connection. Go to /usr/bin/.

2. When Ubuntu prompts that 'x86_64-linux-gnu-gcc' is missing, you need to install the python-dev package:

Solution: sudo apt-get install python -dev -y

3. Command 'gcc' failed with exit status 1

is prompted under CentOS. Solution: yum install gcc python-devel -y

After the installation is complete, enter python and execute import MySQLdb to see if the import can be successful.

Supplement:

When I was operating under ubuntu, I found that I could not connect to the database. ss -lnt found that mysql only listened to the 3306 port on the loopback address, which needs to be modified.
Modify Ubuntu's mysql and change its listening port 127.0.0.1:3306 to allow external connections:
Edit /etc/mysql/my.cnf (the configuration parameters may be in other files in this directory, Look carefully)
Modify bind-address = 0.0.0.0 to allow access from any IP.
Then execute /etc/init.d/mysql restart to restart the mysqlserver service

# The following is an example of Python operating the database:

#!/usr/bin/env python
# -*- coding:utf8 -*-
import MySQLdb
conn = MySQLdb.connect(
host = '192.168.2.14',
port = 3306,
user = 'root',
passwd = '123456',
db = 'demo',
)
# 操作数据库首先需要创建游标
cur = conn.cursor()
# 通过游标cur操作execute()方法可以写入纯sql语句，如下：
# 创建数据表
# cur.execute("create table teacher (id int(5),name varchar(20),class varchar(20),age varchar(10))")
# 插入数据
# cur.execute("insert into teacher values(23,'zhangsan','science',15)")
# 修改数据
# cur.execute("update teacher set id=100 where name='zhangsan'")
# 删除数据
# cur.execute("delete from teacher where id=100")
#插入一条数据【也可以用像下面这种写法】
sqli="insert into teacher values(%s,%s,%s,%s)"
cur.execute(sqli, (23,'zhangsan','science',15))
# 使用executemany一次性向数据表中插入多条值,返回值为受影响的行数。
sqli="insert into teacher values(%s,%s,%s,%s)"
cur.executemany(sqli,[
(11,'wangwu','art',23),
(8,'john','math',22),
(3,'Tom','physical',25),
])
# 最后关闭游标，执行提交操作，并关闭数据库连接
cur.close()
conn.commit()
conn.close()

Retrieve and output data

#!/usr/bin/env python
# -*- coding:utf8 -*-
import MySQLdb
conn = MySQLdb.connect(
host = '192.168.2.14',
port = 3306,
user = 'root',
passwd = '123456',
db = 'demo',
)
cur = conn.cursor()
# 获得表中有多少条数据
aa = cur.execute("select * from teacher")
cur.fetchone() # fetchone()方法可以帮我们获得表中的数据，但是每执行一次输出一行满足条件的值
cur.fetchone()
......
cur.scroll(0,'absolute')# 这样能将游标定位到表中的第一条数据
info = cur.fetchmany(aa)
for i in info:
print i
cur.close()
conn.commit()
conn.close()

The editor will introduce you to this much about Python's database operations. I hope it will be helpful to you!

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