2024.8.2（MySQL）

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.rpm \[root@mysql \~\]# 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.rpm \[root@mysql \~\]# 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\

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 -p123456 mysql\> quit Bye

9、数据库对象

1. 数据库系统 DBMS

2. 数据库 DB

3. 表 table

4. 记录 record

5. 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