数据库
一.基本配置
1.cd /etc/yum.repos.d/
ls
rhel_dvd.repo
vim rhel_dvd.repo 配置yum源

2.yum clean all 清空缓存

3. kill -9 将进程id (如果被占用结束进程)
4. yum clean all 清空缓存
5. yum search mariadb 查看软件包

6. yum install mariadb-server.x86_64 -y 安装软件


7. systemctl start mariadb 打开软件
8. systemctl enable mariadb 设置开机启动

9. netstat -antlupe | grep mysql 查看mysql服务的端口
10. vim /etc/my.cnf 编辑配置文件给数据库加密
内容:
skip-networking=1 开机时跳过网络
[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid
11. systemctl restart mariadb.service 重启服务
12. netstat -antlupe | grep mysql 查看mysql服务的端口

二.设置安全初始化:
1. mysql_secure_installation 命令
2.Enter current password for root (enter for none): 当前root用户密码(没有不用设)
OK, successfully used password, moving on...

3.Set root password? [Y/n] Y 设置数据库密码
New password: 输入密码
Re-enter new password: 再次确认密码
Password updated successfully!
Reloading privilege tables..
... Success! 密码设置成功

三.创建数据库,修改数据苦信息,加密后登陆方式:
1.)mysql -uroot -p (-p后面加密码,回车后输入密码)
mysql命令:(注意每条命令后必须以;结尾。在企业写命令用大写)
1.MariaDB [(none)]> show databases; 显示数据库

2.MariaDB [(none)]> use mysql; 进入数据库
3.MariaDB [mysql]> create database westos; 创建westos数据库

4.MariaDB [(none)]> show databases; 显示数据库

5.MariaDB [mysql]> use westos; 进入westos数据库
6.MariaDB [westos]> create table linux ( 创建linux表
-> username varchar(50) not null,
-> password varchar(50) not null
-> );
7.MariaDB [westos]> select * from linux; 查看linux表
Empty set (0.01 sec)

MariaDB [westos]> desc linux; 查看linux表的数据结构

8.MariaDB [westos]> insert into linux values ('lee','123'); 写入数据
Query OK, 1 row affected (0.04 sec)
9.MariaDB [westos]> select * from linux; 查看linux表

10.MariaDB [westos]> insert into linux values ('lee1','123'); 写入数据
Query OK, 1 row affected (0.02 sec)
11.MariaDB [westos]> select * from linux; 查看linux表

2.)更改linux表信息:
1.MariaDB [westos]> update linux set password='456' where username='lee';
Query OK, 1 row affected (0.09 sec)
Rows matched: 1 Changed: 1 Warnings: 0 把lee密码改为456
2.MariaDB [westos]> select * from linux; 查看表信息

3.MariaDB [westos]> alter table linux add age varchar(4) after username;
Query OK, 2 rows affected (0.50 sec)
Records: 2 Duplicates: 0 Warnings: 0 在username之后加入一个字段age
4.MariaDB [westos]> select * from linux; 查看表

5.MariaDB [westos]> alter table linux drop age; 删除age字段
Query OK, 2 rows affected (0.43 sec)
Records: 2 Duplicates: 0 Warnings: 0
6.MariaDB [westos]> select * from linux; 查询表

7.MariaDB [westos]> alter table linux rename messages; 把linux表名称改为messages
Query OK, 0 rows affected (0.34 sec)
8.MariaDB [westos]> show tables; 显示数据库中的表

3.)删除:
1.MariaDB [westos]> delete from messages where username='lee'; 删除lee
Query OK, 1 row affected (0.03 sec)
2.MariaDB [westos]> select * from messages; 查看表

3.MariaDB [westos]> drop tables messages; 删除messages表
Query OK, 0 rows affected (0.38 sec)
4.MariaDB [westos]> show databases; 查看数据库
5.MariaDB [westos]> drop database westos; 删除数据库
Query OK, 0 rows affected (0.00 sec)
6.MariaDB [(none)]> show databases; 查看数据库

四.用户登陆授权:
1.
MariaDB [(none)]>create database westos; 创建库
Query OK, 1 row affected (0.00 sec)

2.MariaDB [(none)]> create table westos.linux( username varchar(50) not null,
-> password varchar(50) not null)
-> ;
Query OK, 0 rows affected (0.36 sec)
创建linux表
3.MariaDB [(none)]> insert into westos.linux values ('lee','123'); 写入信息
Query OK, 1 row affected (0.35 sec)

4.MariaDB [westos]> select * from linux; 查看表

5.MariaDB [westos]> grant select on *.* to westos@locahost; 给westos的本地用户授权,查询所有数据库内容
Query OK, 0 rows affected (0.00 sec)
6.MariaDB [westos]> show grants for westos@locahost; 查看westos本地用户的权限

7.MariaDB [westos]> grant update on *.* to westos@locahost; 本地用户授权更新
Query OK, 0 rows affected (0.00 sec)
8.MariaDB [westos]> show grants for westos@locahost; 查看权限

9.MariaDB [westos]> grant SELECT,INSERT on westos.* to lee@locahost;
Query OK, 0 rows affected (0.00 sec) 给lee用户在wstos库下权限
五.数据库的备份:
1.mysqldump -uroot -plinux westos > /mnt/westos.sql
把westos数据库备份到/mnt/westos.sql里面
2.drop database westos; 删除westos库
3.vim westos.sql 编辑文件
内容:
CREATE DATABASE westos; 创建westos库
USE westos; 进入到库里
DROP TABLE IF EXISTS `linux`;
4.mysql -uroot -plinux < /mnt/westos.sql 将/mnt/westos.sql导入到westos库里
5.mysql -uroot -p 登陆
6.MariaDB [(none)]> show databases; 查看所有库

六.数据库root密码更改:
1.systemctl stop mariadb.service 关闭数据库服务
2. mysqld_safe --skip-grant-tables & 跳过网络打入后台
3.mysql 登陆

4.use mysql; 进入数据库
5.select * from user; 查看root密码

6.MariaDB [mysql]> update mysql.user set Password=password('redhat') where User='root';
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0 修改密码,成功后退出
7. mysqld_safe --skip-grant-tables 跳过初始化认证

8. killall -9 mysqld_safe 有进程时候,结束进程
[1]+ Killed mysqld_safe --skip-grant-tables
9. ps aux | grep mysql 查看mysql其他进程

10. kill -9 4659 结束进程
11. systemctl restart mariadb 重启服务
12. mysql -uroot -predhat 登陆(密码修改成功)
