1、mysql 5.7 ubuntu17.04

系统：ubuntu17.04

数据库主要分文档型和服务型两类：

文档型：如sqlite3 （17.04自带/usr/bin/sqlite3）就是一个文件，应用在移动端如手机，pad，家电等

服务型：如mysql有服务端（存储数据）和客户端

mysql数据库是关系型数据库，采用E-R模型即实体-联系（或关系）模型

安装：

sudo apt install mysql-server，需要设置密码：xxx

sudo apt install mysql-client

sudo apt install libmysqlclient-dev

lyb@lyb:~$ sudo netstat -tap | grep mysql
tcp        0      0 localhost:mysql         *:*                     LISTEN      5167/mysqld

成功安装

登录：

l@l:~$ mysql -uroot -pxxx
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 5
Server version: 5.7.20-0ubuntu0.16.04.1 (Ubuntu)

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

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> show databases;　　#初始有四个数据库
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.16 sec)

创建用户并授权：

mysql> create user 'l'@'%' identified by '123';
Query OK, 0 rows affected (0.09 sec)

mysql> select user,host from user;
+---------------+-----------+
| user          | host      |
+---------------+-----------+
| l           | %         |
| mysql.session | localhost |
| mysql.sys     | localhost |
| root          | localhost |
+---------------+-----------+
4 rows in set (0.00 sec)

mysql> grant select on study.* to 'l'@'%';

desc  user；　　#显示其中user表的结构，如下：

+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Field                  | Type                              | Null | Key | Default               | Extra |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Host                   | char(60)                          | NO   | PRI |                       |       |
| User                   | char(32)                          | NO   | PRI |                       |       |
| Select_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Insert_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Update_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Delete_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Create_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Drop_priv              | enum('N','Y')                     | NO   |     | N                     |       |
| Reload_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Shutdown_priv          | enum('N','Y')                     | NO   |     | N                     |       |
| max_user_connections   | int(11) unsigned                  | NO   |     | 0                     |       |
| plugin                 | char(64)                          | NO   |     | mysql_native_password |       |
| authentication_string  | text                              | YES  |     | NULL                  |       |
| password_expired       | enum('N','Y')                     | NO   |     | N                     |       |
| password_last_changed  | timestamp                         | YES  |     | NULL                  |       |
| password_lifetime      | smallint(5) unsigned              | YES  |     | NULL                  |       |
| account_locked         | enum('N','Y')                     | NO   |     | N                     |       |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+

注：字段创建要有数据类型，长度；Null是否为空，NO表示不能为空；PRI表示主键，一般是一个，本表前两个是联合主键

select  字段  from  表

exit；　　#从mysql数据库退出

ps -ef |grep mysql　　#在命令行从所有进程筛选mysql