第四单元 mysql 数据库的基本管理

1.什么是数据库    数据库就是个高级的表格软件

2.常见数据库  Mysql Oracle
3.Mysql (SUNmongodbdb2 sqlite sqlserver .......-----> Oracle)
4.mariadb
数据库中的常用名词
1.字段:表格中的表头
2.表:表格
3.库:存放表格的目录
4.查询:对表格中的指定内容进行查看

dnf install mariadb-server -y

systemctl enable --now  mariadb
rpm -qc mariadb-server   查询mariadb配置文件

/etc/my.cnf.d/mariadb-server.cnfll /

var/lib/mysql    数据目录,当需要重新安装mariadb时需要清理此目录或备份

[root@westoslinux112 yum.repos.d]# netstat -antlupe | grep mysql
tcp6       0      0 :::3306                 :::*                    LISTEN      27         73763      17527/mysqld        
[root@westoslinux112 yum.repos.d]# vim /etc/my.cnf.d/mariadb-server.cnf

编辑内容：

skip-netmorking=1
[root@westoslinux112 yum.repos.d]# systemctl restart mariadb
[root@westoslinux112 yum.repos.d]# netstat -antlupe | grep mysql

 mysql_secure_installation
[root@Mariadb ~]# mysql          默认不需要密码,初始化完毕后需要
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
[root@Mariadb ~]# mysql -uroot -p                     u 指定登陆用户 -p 密码

1.查看
SHOW DATAbaseS;     ##显示库名称
USE mysql;          ##进入mysql库
SHOW TABLES;        ##显示库中的所有表
SELECt * FROM user; ##查询所有数据
SELECt Host,User,Password FROM user;    ##查询指定字段
SELECt Host FROM mysql.user WHERe User='root'

 2.新建
CREATE DATAbase westos;    ##新建库
CREATE TABLE user (        ##新建表
username varchar(6) not null,
password varchar(30) not null
);
DESC userlist;                                 ##显示表结构
INSERT INTO userlist VALUES ('user1','123');   #插入数据
SELECt * FROM userlist
FLUSH PRIVILEGES;                           #刷新数据库

 3.更改

UPDATe userlist SET password='456' WHERe username='user2';
username='user2';

ALTER userlist RENAME user;

SHOW TABLES;SHOW TABLES; 

ALTER TABLE user add address VARCHAr(50);

ALTER TABLE user add age VARCHAr(4) AFTER password;

DESC user;

 4.删除

DELETE FROM westos.user WHERe username='user1'

SELECt * FROM westos.user;

DROp TABLE westos.user;

DROP DATAbase westos;

SHOW DATAbaseS;

1.当密码没有改过时，可以执行命令
[root@westoslinux112 yum.repos.d]# mysqladmin -uroot -p password lee
Enter password:    输入旧密码

[root@westoslinux112 yum.repos.d]# mysql -uroot -p
Enter password:
Welcome to the MariaDB monitor.  Commands end with ; or g.  修改成功

2.当密码改过时，可执行命令：

systemctl stop mariadb
mysqld_safe --skip-grant-tables &

UPDATE mysql.user SET Password=password('westos') WHERe User='root';  ##当未使用过mysladmin更改过
密码
UPDATE mysql.user SET authentication_string=password('westos') WHERe User='root'; ##当使用过mysladmin更改过密码

[root@westoslinux112 yum.repos.d]# systemctl stop mariadb
[root@westoslinux112 yum.repos.d]# mysqld_safe --skip-grant-tables &
[1] 31421
[root@westoslinux112 yum.repos.d]# 211110 21:02:43 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
211110 21:02:44 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

[root@westoslinux112 yum.repos.d]# mysql -uroot -p
Enter password:
Welcome to the MariaDB monitor.  Commands end with ; or g.
Your MariaDB connection id is 8
Server version: 10.3.17-MariaDB MariaDB Server

MariaDB [(none)]> UPDATe mysql.user SET authentication_string=password('westos') WHERe User='root';

[root@westoslinux112 yum.repos.d]# fg    （crtl+z）
mysqld_safe --skip-grant-tables
^Z
[1]+  Stopped                 mysqld_safe --skip-grant-tables

[root@westoslinux112 yum.repos.d]# killall -9 mysqld_safe
[1]+  Killed                  mysqld_safe --skip-grant-tables
[root@westoslinux112 yum.repos.d]# ps aux | grep mysql
mysql      31515  0.2 10.5 1340688 88552 pts/1   Sl   21:02   0:00 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mariadb/plugin --user=mysql --skip-grant-tables --log-error=/var/log/mariadb/mariadb.log --pid-file=/run/mariadb/mariadb.pid --socket=/var/lib/mysql/mysql.sock
root       31612  0.0  0.1  12108  1044 pts/1    S+   21:09   0:00 grep --color=auto mysql
[root@westoslinux112 yum.repos.d]# kill -9 31515
[root@westoslinux112 yum.repos.d]# ps aux | grep mysql
root       31614  0.0  0.1  12108   988 pts/1    R+   21:09   0:00 grep --color=auto mysql

[root@westoslinux112 yum.repos.d]# systemctl start mariadb
[root@westoslinux112 yum.repos.d]# mysql -uroot -p
Enter password:                    密码修改成功

CREATE USER westos@localhost identified by 'westos';  只能用localhost登陆
CREATE USER westos@% identified by '%';       ##可以通过网络或localhost登陆

CREATE USER westos@localhost identified by 'westos';

 SELECT User from mysql.user;

mysql -uroot -p 

SHOW DATAbaseS;  没有权限什么都看不到

GRANT SELECt ON *.* TO westos@localhost;     添加查看权限

MariaDB [(none)]> SHOW GRANTS FOR westos@localhost;
+----------------------------------------------------------------------------------------------------------------+
| Grants for westos@localhost                                                                                    |
+----------------------------------------------------------------------------------------------------------------+
| GRANT SELECT ON *.* TO 'westos'@'localhost' IDENTIFIED BY PASSWORD '*28C1E2BE21B45562A34B6CC34A19CFAFC2F88F96' |      添加成功

GRANT INSECT ON *.* TO westos@localhost;      添加插入权限

---------------------+
| Grants for westos@localhost                                                                                            |
+------------------------------------------------------------------------------------------------------------------------+
| GRANT SELECT, INSERT ON *.* TO 'westos'@'localhost' IDENTIFIED BY PASSWORD '*28C1E2BE21B45562A34B6CC34A19CFAFC2F88F96' |     添加成功

MariaDB [(none)]> REVOKE INSERT ON *.* FROM westos@localhost;    移除插入权限
Query OK, 0 rows affected (0.000 sec)            

mysql -uroot -pwestos -e "CREATE DATAbase westos;"
mysql -uroot -pwestos -e "CREATE TABLE westos.user(user varchar(10) not null,passwd varchar(50) not null);"
mysql -uroot -pwestos -e "INSERT INTO westos.user VALUES ('user1','123'),('user2','123');"
mysql -uroot -pwestos -e "SELECt * FROM westos.user;"
mysqldump -uroot -pwestos --all-database --no-data
mysqldump -uroot -pwestos westos > /mnt/westos.sql
ls /mnt
mysql -uroot -pwestos -e "DROp DATAbase westos"
[root@westoslinux112 squid]# mysql -uroot -pwestos westos < /mnt/westos.sql
ERROR 1049 (42000): Unknown database 'westos'
[root@westoslinux112 squid]# mysql -uroot -pwestos -e "CREATE DATAbase westos;"
[root@westoslinux112 squid]# mysql -uroot -pwestos westos < /mnt/westos.sql
[root@westoslinux112 squid]# mysql -uroot -pwestos -e "SELECT * FROM westos.user;"
+-------+--------+
| user  | passwd |
+-------+--------+
| user1 | 123    |
| user2 | 123    |
+-------+--------+
[root@westoslinux112 squid]#  mysql -uroot -pwestos -e "DROp DATAbase westos;"
[root@westoslinux112 squid]# vim /mnt/westos.sql
编辑内容：
CREATE DATAbase westos;
USE westos;
[root@westoslinux112 yum.repos.d]# mysql -uroot -pwestos < /mnt/westos.sql
[root@westoslinux112 squid]# mysql -uroot -pwestos -e "SELECT * FROM westos.user;"
+-------+--------+
| user  | passwd |
+-------+--------+
| user1 | 123    |
| user2 | 123    |
+-------+--------+

phpmyadmin的安装
cd /mnt
[root@westoslinux112 mnt]# wget http://172.25.254.250/software/phpMyAdmin-3.4.0-all-languages.tar.bz2
dnf install httpd php php-mysqlnd -y
systemctl enable --now httpd
[root@westoslinux112 mnt]# tar jxf  phpMyAdmin-3.4.0-all-languages.tar.bz2 -C /var/www/html/
[root@westoslinux112 mnt]# ls /var/www/html/
phpMyAdmin-3.4.0-all-languages
[root@westoslinux112 mnt]# cd /var/www/html/
[root@westoslinux112 html]# mv phpMyAdmin-3.4.0-all-languages/ myadmin
[root@westoslinux112 html]# cd myadmin
[root@westoslinux112 myadmin]# less README
[root@westoslinux112 myadmin]# less documentation.txt
[root@westoslinux112 myadmin]# cp config.sample.inc.php config.inc.php
[root@westoslinux112 myadmin]# vim config.inc.php
编辑内容：
$cfg['blowfish_secret'] = 'ba17c1ec07d65003';

[root@westoslinux112 myadmin]# systemctl restart httpd
Job for httpd.service failed because the control process exited with error code.
See "systemctl status httpd.service" and "journalctl -xe" for details.
[root@westoslinux112 myadmin]# systemctl stop squid
[root@westoslinux112 myadmin]# systemctl restart httpd
在浏览器上访问172.25.254.112/myadmin