一、mysql
1、下载mysql软件包
root@mysql \~# yum -y install wget
root@mysql \~# wget https://downloads.mysql.com/archives/get/p/23/file/mysql-8.0.33-1.el7.x86_64.rpm-bundle.tar
2、解压
root@mysql \~# tar -xf mysql-8.0.33-1.el7.x86_64.rpm-bundle.tar
3、安装依赖包
root@mysql \~# rpm -e --nodeps mariadb-libs
root@mysql \~# rpm -ivh mysql-community-common-8.0.33-1.el7.x86_64.rpm
root@mysql \~# rpm -ivh mysql-community-client-plugins-8.0.33-1.el7.x86_64.rpmroot@mysql \~# rpm -ivh mysql-community-libs-8.0.33-1.el7.x86_64.rpm
root@mysql \~# rpm -ivh mysql-community-client-8.0.33-1.el7.x86_64.rpm
root@mysql \~# rpm -ivh mysql-community-icu-data-files-8.0.33-1.el7.x86_64.rpmroot@mysql \~# rpm -ivh mysql-community-server-8.0.33-1.el7.x86_64.rpm
4、初始化mysqld服务
root@mysql \~# mysqld --initialize --console
5、添加权限 启动服务
root@mysql \~# chown -R mysql:mysql /var/lib/mysql/
root@mysql \~# systemctl start mysqld
6、在/var/log/mysqld.log中找到初始密码，复制
root@mysql \~# cat /var/log/mysqld.log | grep localhost
2024-08-02T01:49:19.435048Z 6 Note MY-010454 Server A temporary password is generated for root@localhost: dQ1o<YO&YNyX 密码
7、登录管理
root@mysql \~# mysql -uroot -p
Enter password: 密码mysql>
8、设置新的密码
mysql> alter user 'root'@'localhost'identified by '123456';
Query OK, 0 rows affected (0.01 sec)
root@mysql \~# mysql -uroot -p123456mysql> quit
Bye
9、数据库对象
数据库系统 DBMS
数据库 DB
表 table
记录 record
字段 feild
10、数据库操作
1. 数据库操作
1.1 查看数据库
1.2 创建库
1.3 删除库
2. 表的操作
2.1 选择库
2.2 查看表
2.3 创建表
语法：create table user( id int primarykey,username varchar，password varchar );
mysql> create table `test1`(
`id` int not null auto_increment,
`username` varchar(45) not null,
`password` varchar(45) not null,
primary key(`id`)
);
2.4 删除表
mysql> drop table user0;
Query OK, 0 rows affected (0.01 sec)
2.5 其他
2.5.1 新增列
ALTER TABLE `test`
ADD COLUMN `realname` VARCHAR(45) NULL AFTER `password`;
2.5.2 修改列名
mysql> ALTER TABLE `test`
-> CHANGE COLUMN `realname` `zsxm` VARCHAR(45) NULL DEFAULT NULL ; Query OK, 0 rows affected (0.02 sec)
Records: 0 Duplicates: 0 Warnings: 0
2.5.3 删除列
mysql> ALTER TABLE `test`
-> DROP COLUMN `zsxm`;
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0
3. 记录的操作
1. 新增
#insert into 表名 (字段名列表) values (字段值列表)
mysql> insert into test (id,username,password) values (3,'zhangsan','zhangsan');
Query OK, 1 row affected (0.01 sec)
mysql> insert into test(username,password)values('lisi','lisi');
Query OK, 1 row affected (0.00 sec)
2. 删除
delte from user where 条件;
mysql> delete from test where username='zhangsan';
Query OK, 1 row affected (0.00 sec)
3. 修改
mysql> insert into user values (1,'zhangsan','zhangsan');
Query OK, 1 row affected (0.00 sec)
mysql> update user set password=123 where username='zhangsan';
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0