随着人工智能和深度学习的风暴来临，Python变得越来越火热，作者也准备从零学习这些知识，写相关文章。本篇文章讲解阿里云服务器CentOS系统下的MySQL数据库开启及配置过程，同时教大家如何编写Python操作MySQL数据库的基础代码，为后面的网络爬虫并存储至服务器打下基础。文章非常基础，希望这系列文章对您有所帮助，如果有错误或不足之处，还请海涵~
系列文章：
一. MySQL数据库开启
1.检查数据库是否安装
- 命令：rpm -qa | grep mysql
2.检查MySQL服务是否开启
- 命令：service mysqld status
3.开启MySQL服务
- 命令：service mysqld start
可以看到 /usr/bin 目录下存在mysqladmin命令。
4.使用root用户登录mysql数据
- 命令：mysqladmin -u root -p password 123456
但是报如下错，这是连接MySQL数据库最常见的一个错误，怎么解决呢？
mysqladmin: connect to server at 'localhost' failed error: 'Access denied for user 'root'@'localhost' (using password: NO)'
5.更新root密码登录
命令如下：
--关闭服务
service mysqld stop
--安装赋权限
mysqld_safe --skip-grant-tables &
--root用户登录
mysql -u root -p
--输入密码
123456
--使用数据库
use mysql;
--更新密码
update user set password=PASSWORD("123456") where user="root";
--更新权限
flush privileges;
--退出
quit
--服务器重启
service mysqld restart
--root用户登录
mysql -u root -p
新密码进入如下图所示：
然后输入“use mysql;”使用数据库，尝试“show databases;”显示所有数据库。
接下来就是更新root用户的密码：
6.重启服务本地连接mysql数据库
- 命令：service mysqld restart
- 命令：mysql -u root -p
二. MySQL数据库增加新用户
1.使用mysql数据库
- 命令：use mysql;
2.显示所有表
- 命令：show tables;
这里我们使用user表，定义mysql数据库的用户。
3.查看表结构
- 命令：describe user;
| Host | char(60) | NO | PRI | | |
| User | char(16) | NO | PRI | | |
| Password | char(41) | NO | | | |4.添加一个新用户yxz，密码为123456
命令如下：
mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> insert into mysql.user(Host,User,Password) value ("localhost","yxz",password("123456"));
Query OK, 1 row affected, 3 warnings (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> create database Eastmount;
Query OK, 1 row affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| Eastmount |
| junyun |
| mysql |
| test |
+--------------------+
5 rows in set (0.00 sec)
mysql> grant all privileges on Eastmount.* to yxz@localhost identified by "yxz";
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql>quit;如下图所示：
但是同样报错：error: 'Access denied for user 'root'@'localhost' (using password: NO)'，需要像前面一样修订密码，代码如下：
[root@iZ2ze9134z8zlqupc9t6mzZ ~]# service mysqld stop
Stopping mysqld: [ OK ]
[root@iZ2ze9134z8zlqupc9t6mzZ ~]# mysqld_safe --skip-grant-tables &
[1] 24403
[root@iZ2ze9134z8zlqupc9t6mzZ ~]# 180217 13:50:37 mysqld_safe Logging to '/var/log/mysqld.log'.
180217 13:50:37 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
mysql -u yxz -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.73 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| Eastmount |
| junyun |
| mysql |
| test |
+--------------------+
5 rows in set (0.00 sec)
mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> update user set password=PASSWORD("123456") where user="yxz";
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> quit;三. SQL语句
1.root登录并进入Eastmount数据库
命令如下：
[root@iZ2ze9134z8zlqupc9t6mzZ ~]# mysql -u yxz -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.1.73 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| Eastmount |
| test |
+--------------------+
3 rows in set (0.00 sec)
mysql> use Eastmount;
Database changed
mysql> show tables;
Empty set (0.00 sec)
mysql>2.创建表
命令如下：
create table student(
id int not null primary key,
name varchar(16) not null,
pwd varchar(20) not null
);3.显示表结构
- 命令：describe student;
4.插入数据
- 命令：insert into student(id,name,pwd) values(1,'yxz','111111');
5.查询数据
- 命令：select * from student;
6.更新数据
- 命令：update student set pwd='123456' where name='yxz';
7.删除数据
- 命令：delete from student where id='1';
8.删除表
- 命令：drop table studentl;
总之，希望这篇基础文章对您有所帮助，尤其是刚接触云服务器的新手，如果您是高手，还请多提意见，共同提高。很高兴重回阿里云，开心能与大家在这里认识，希望能分享更高质量的文章帮助大家，且行且珍惜。
（By：Eastmount 2021-11-09 夜于武汉）
