首页 > 数据库> > mysql基础

mysql基础

2022-07-24 14:34:41 作者：互联网

mysql基础
2. mysql安装与配置
- 2.1 mysql安装
  - 2.2 mysql配置
- 3.mariadb安装与配置
  - 3.1 mariadb安装

mysql基础

数据库

关系型数据库

：存储在硬盘

mysql：5.7版本前是开源软件
oracle：商业软件
mariadb：开源软件，由mysql原班人马开发
sqlserver 商业软件
MSSQL： MicroSoft 微软sql

nosql

：存储在内存，变量的形式key=value

redis
memcache
mongodb
pgsql

sqlite

：数据是存放在“文件（数据文件）”中

1关系型数据库介绍

1.1 数据结构模型

数据结构模型主要有：

层次模型
网状结构
关系模型

关系模型：
二维关系：row，column

数据库管理系统：DBMS
关系：Relational，RDBMS

1.2 RDBMS专业名词

常见的关系型数据库管理系统：

MySQL：MySQL，MariaDB，Percona-Server
PostgreSQL：简称为pgsql
Oracle
MSSQL
SQL：Structure Query Language，结构化查询语言

约束：constraint，向数据表提供的数据要遵守的限制

主键约束：一个或多个字段的组合，填入的数据必须能在本表中唯一标识本行。且必须提供数据，不能为空（NOT NULL）。
一个表只能存在一个
惟一键约束：一个或多个字段的组合，填入的数据必须能在本表中唯一标识本行。允许为空（NULL）
一个表可以存在多个
外键约束：一个表中的某字段可填入数据取决于另一个表的主键已有的数据
检查性约束

索引：将表中的一个或多个字段中的数据复制一份另存，并且这些数据需要按特定次序排序存储

1.3 关系型数据库的常见组件

关系型数据库的常见组件有：

数据库：database
表：table，由行（row）和列（column）组成
索引：index
视图：view
用户：user
权限：privilege
存储过程：procedure
存储函数：function
触发器：trigger
事件调度器：event scheduler

1.4 SQL语句

SQL语句有三种类型：

DDL：Data Defination Language，数据定义语言
DML：Data Manipulation Language，数据操纵语言
DCL：Data Control Language，数据控制语言

|SQL语句类型 |对应操作|
|--- |: -----|
|DDL |CREATE：创建； DROP：删除；ALTER：修改；|
|DML |INSERT：向表中插入数据；DELETE：删除表中数据；UPDATE：更新表中数据；SELECT：查询表中数据；|
|DCL |GRANT：授权；REVOKE：移除授权；|

2. mysql安装与配置

2.1 mysql安装

mysql安装方式有三种：

源代码：编译安装
二进制格式的程序包：展开至特定路径，并经过简单配置后即可使用
程序包管理器管理的程序包：
rpm：有两种
- OS Vendor：操作系统发行商提供的
- 项目官方提供的
deb

配置mysql的yum源
1.下载mysql的yum repository

[root@localhost ~]# wget http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm

2.更新下载好的yum repository

[root@localhost ~]#  rpm -Uvh mysql57-community-release-el7-11.noarch.rpm

3.查看/etc/yum.repos.d/下多了两个mysql的repo

[root@localhost ~]# ls /etc/yum.repos.d/
myrepo.repo  mysql-community.repo  mysql-community-source.repo

4.开始安装mysql，安装前先禁用默认的mysql模块

[root@localhost ~]# yum module disable mysql
[root@localhost ~]# yum -y install mysql-community-server mysql-community-client mysql-community-common mysql-community-devel --nogpgcheck

2.2 mysql配置

启动mysql并设置开机自动启动

[root@localhost ~]# systemctl enable --now mysqld

查看3306端口已经监听

[root@localhost ~]# systemctl status mysqld
● mysqld.service - MySQL Server
   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
   Active: active (running) since Sun 2022-07-24 13:57:18 CST; 3min 9s ago
     Docs: man:mysqld(8)
           http://dev.mysql.com/doc/refman/en/using-systemd.html
  Process: 2729 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
  Process: 2679 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
 Main PID: 2731 (mysqld)
    Tasks: 27 (limit: 11201)
   Memory: 316.4M
   CGroup: /system.slice/mysqld.service
           └─2731 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid

Jul 24 13:57:14 localhost.localdomain systemd[1]: Starting MySQL Server...
Jul 24 13:57:18 localhost.localdomain systemd[1]: Started MySQL Server.

[root@localhost ~]# ss -antl
State            Recv-Q            Send-Q                       Local Address:Port                       Peer Address:Port           Process           
LISTEN           0                 128                                0.0.0.0:22                              0.0.0.0:*                                
LISTEN           0                 80                                       *:3306                                  *:*                                
LISTEN           0                 128                                   [::]:22                                 [::]:*

在日志文件中找出临时密码

[root@localhost ~]# grep "password" /var/log/mysqld.log 
2022-07-24T05:57:15.560498Z 1 [Note] A temporary password is generated for root@localhost: g>u%=yugt6gW

使用获取到的临时密码登录mysql，密码为 g>u%=yugt6gW

[root@localhost ~]# mysql -uroot -p
Enter password: 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
[root@localhost ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.38

Copyright (c) 2000, 2022, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

修改mysql登录密码

mysql> alter user 'root'@'localhost' identified by 'Luojialong123!';
Query OK, 0 rows affected (0.00 sec)

使用新密码登录mysql

[root@localhost ~]# mysql -uroot -pLuojialong123!
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.38 MySQL Community Server (GPL)

Copyright (c) 2000, 2022, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

避免mysql自动升级,卸载最开始安装的yum源

[root@localhost ~]# rpm -e mysql57-community-release

3.mariadb安装与配置

3.1 mariadb安装

[root@localhost ~]# yum -y install mariadb*
[root@localhost ~]# systemctl enable --now mariadb
[root@localhost ~]# systemctl  status mariadb
● mariadb.service - MariaDB 10.3 database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: d>
   Active: active (running) since Sun 2022-07-24 02:21:37 EDT; 19s ago
     Docs: man:mysqld(8)
           https://mariadb.com/kb/en/library/systemd/
  Process: 7967 ExecStartPost=/usr/libexec/mysql-check-upgrade (code=exited, status=0>
  Process: 7831 ExecStartPre=/usr/libexec/mysql-prepare-db-dir mariadb.service (code=>
  Process: 7806 ExecStartPre=/usr/libexec/mysql-check-socket (code=exited, status=0/S>
 Main PID: 7936 (mysqld)
   Status: "Taking your SQL requests now..."
    Tasks: 30 (limit: 4615)
   Memory: 103.9M
   CGroup: /system.slice/mariadb.service
           └─7936 /usr/libexec/mysqld --basedir=/usr

设置密码

[root@localhost ~]# mysql
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 8
Server version: 10.3.28-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> set password = password('123456');
Query OK, 0 rows affected (0.000 sec)

MariaDB [(none)]> \q
Bye

测试登录

[root@localhost ~]# mysql -uroot -p123456
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 9
Server version: 10.3.28-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

标签：mariadb,基础,mysqld,mysql,MariaDB,root,localhost
来源： https://www.cnblogs.com/loronoa/p/16514472.html