数据库的安装初始化及管理

1.官网下载或者wget

[root@mysql ~]# ls

anaconda-ks.cfg

initserver.sh

mysql-8.0.33-1.el7.x86_64.rpm-bundle.tar

mysql-community-client-8.0.33-1.el7.x86_64.rpm

mysql-community-client-plugins-8.0.33-1.el7.x86_64.rpm

mysql-community-common-8.0.33-1.el7.x86_64.rpm

mysql-community-debuginfo-8.0.33-1.el7.x86_64.rpm

mysql-community-devel-8.0.33-1.el7.x86_64.rpm

mysql-community-embedded-compat-8.0.33-1.el7.x86_64.rpm

mysql-community-icu-data-files-8.0.33-1.el7.x86_64.rpm

mysql-community-libs-8.0.33-1.el7.x86_64.rpm

mysql-community-libs-compat-8.0.33-1.el7.x86_64.rpm

mysql-community-server-8.0.33-1.el7.x86_64.rpm

mysql-community-server-debug-8.0.33-1.el7.x86_64.rpm

mysql-community-test-8.0.33-1.el7.x86_64.rpm

2.确定mysql-community-server正常安装之后就可以开始配置

3.初始化mysqld 服务 mysqld initeialize

4.启动服务 systemctl start mysqld

5.添加开机启动列表 systecmctrl enable mysqld

6.在/var/log/mysql.log中找到初始密码，前后复制空格7.登录管理 mysql -uroot -p

将复制的密码粘贴到输入密码的区

域，实现登录

8.设置新的密码

9.退出登录

**1.****数据库的对象 **

1.数据库系统 DBMS

2.数据库

DB

3.表

table

4.记录

record

5.字段

feild

**1.****数据库操作 **

删除库

**创建库 **

mysql> create datababse test charset utf8;

Query OK, 1 row affected, 1 warning (0.01 sec)

mysql> show databases;**查看库 **

**2.****表的操作 **

**1.****选择库 **

+--------------------+

mysql> create datababse test charset utf8;

Query OK, 1 row affected, 1 warning (0.01 sec)

mysql> show databases;**查看库 **

**2.****表的操作 **

**1.****选择库 **

**2.**查看表

**3.**创建表

mysql> CREATE TABLE test.user (

-> id INT NOT NULL AUTO_INCREMENT,

-> username VARCHAR(45) NOT NULL,

-> password VARCHAR(45) NOT NULL,

-> PRIMARY KEY (id),

-> UNIQUE INDEX username_UNIQUE (username ASC)

VISIBLE)

-> COMMENT = 'us';

mysql> show tables;

+----------------+

| Tables_in_test |

+----------------+

| user |

| user0 |

**4.****删除表 **

**新增列 **

mysql> show tables;

+----------------+

| Tables_in_test |

+----------------+

| user |

| user0 |

+----------------+

2 rows in set (0.00 sec)

mysql> drop table user0;

Query OK, 0 rows affected (0.01 sec)

mysql> show tables;

+----------------+

| Tables_in_test |

+----------------+

| user |

+----------------+

1 row in set (0.01 sec)

ALTER TABLE test.user

ADD COLUMN realname VARCHAR(45) NULL AFTER password;

mysql> desc user;

+----------+-------------+------+-----+---------+---------

-------+

| Field | Type | Null | Key | Default | Extra

|

+----------+-------------+------+-----+---------+---------

-------+

| id | int | NO | PRI | NULL |

auto_increment |

| username | varchar(45) | NO | UNI | NULL |

|**修改列名 **

| password | varchar(45) | NO | | NULL |

|

| realname | varchar(45) | YES | | NULL |

|

+----------+-------------+------+-----+---------+---------

-------+

4 rows in set (0.01 sec)

mysql> ALTER TABLE test.user

-> CHANGE COLUMN realname zsxm VARCHAR(45) NULL

DEFAULT NULL ;

Query OK, 0 rows affected (0.02 sec)

Records: 0 Duplicates: 0 Warnings: 0

mysql> desc user;

+----------+-------------+------+-----+---------+---------

-------+

| Field | Type | Null | Key | Default | Extra

|

+----------+-------------+------+-----+---------+---------

-------+

| id | int | NO | PRI | NULL |

auto_increment |

| username | varchar(45) | NO | UNI | NULL |

|

| password | varchar(45) | NO | | NULL |

|

| zsxm | varchar(45) | YES | | NULL |

|

+----------+-------------+------+-----+---------+---------

-------+**删除列 **

5.其他

3.记录的操作

1. 新增

mysql> ALTER TABLE test.user

-> DROP COLUMN zsxm;

Query OK, 0 rows affected (0.01 sec)

Records: 0 Duplicates: 0 Warnings: 0

mysql> desc user;

+----------+-------------+------+-----+---------+---------

-------+

| Field | Type | Null | Key | Default | Extra

|

+----------+-------------+------+-----+---------+---------

-------+

| id | int | NO | PRI | NULL |

auto_increment |

| username | varchar(45) | NO | UNI | NULL |

|

| password | varchar(45) | NO | | NULL |

|

+----------+-------------+------+-----+---------+---------

-------+

3 rows in set (0.00 sec)

#insert into 表名 (字段名列表) values (字段值列表)

mysql> select * from user;

Empty set (0.00 sec)

mysql> insert into user (id,username,password) values

(3,'zhangsan','zhangsan');Query OK, 1 row affected (0.01 sec)

mysql> select * from user;

+----+----------+----------+

| id | username | password |

+----+----------+----------+

| 3 | zhangsan | zhangsan |

+----+----------+----------+

1 row in set (0.00 sec)

mysql> select * from user;

+----+----------+----------+

| id | username | password |

+----+----------+----------+

| 3 | zhangsan | zhangsan |

+----+----------+----------+

1 row in set (0.00 sec)

mysql> insert into

user(username,password)values('lisi','lisi');

Query OK, 1 row affected (0.00 sec)

mysql> select * from user;

+----+----------+----------+

| id | username | password |

+----+----------+----------+

| 3 | zhangsan | zhangsan |

| 4 | lisi | lisi |

+----+----------+----------+

2 rows in set (0.00 sec)

mysql> desc user;

+----------+-------------+------+-----+---------+------

----------+

| Field | Type | Null | Key | Default | Extra

|+----------+-------------+------+-----+---------+------

----------+

| id | int | NO | PRI | NULL |

auto_increment |

| username | varchar(45) | NO | UNI | NULL |

|

| password | varchar(45) | NO | | NULL |

|

+----------+-------------+------+-----+---------+------

----------+

3 rows in set (0.00 sec)

1. 删除

delte from user where 条件;

mysql> delete from user where username='zhangsan';

Query OK, 1 row affected (0.00 sec)

mysql> select * from user;

+----+----------+----------+

| id | username | password |

+----+----------+----------+

| 4 | lisi | lisi |

+----+----------+----------+

1 row in set (0.00 sec)

mysql> delete from user;

Query OK, 1 row affected (0.00 sec)mysql> select * from user;

Empty set (0.00 sec)

1. 修改

mysql>

mysql> insert into user values

(1,'zhangsan','zhangsan');

Query OK, 1 row affected (0.00 sec)

mysql> insert into user values (2,'lisi','lisi');

Query OK, 1 row affected (0.00 sec)

mysql> insert into user values (3,'wangwu','wangwu');

Query OK, 1 row affected (0.00 sec)

mysql> select * from user;

+----+----------+----------+

| id | username | password |

+----+----------+----------+

| 1 | zhangsan | zhangsan |

| 2 | lisi | lisi |

| 3 | wangwu | wangwu |

+----+----------+----------+

3 rows in set (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

mysql> select * from user;

+----+----------+----------+

| id | username | password |

+----+----------+----------+

| 1 | zhangsan | 123 || 2 | lisi | lisi |

| 3 | wangwu | wangwu |

+----+----------+----------+

3 rows in set (0.00 sec)

1. 查询