Installation and basic operation of Mysql database

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basic operation

1. Mysql database installation and environment configuration

1. Database download

Mysql download address


Click to download and decompress,
remember the decompression address

2. Environment configuration

Create a new input path to the bin directory after decompression in path

3. Configure the my.ini file

Find the decompression directory and create a new my.ini file

, enter the following content to save

[mysqld]
#端口号
port = 3306
#mysql-5.7.27-winx64的路径
basedir=E:\Program Files\Mysql\mysql-5.7.27-winx64
#mysql-5.7.27-winx64的路径+\data
datadir=E:\Program Files\Mysql\mysql-5.7.27-winx64\data 
#最大连接数
max_connections=200
#编码
character-set-server=utf8

default-storage-engine=INNODB

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

[mysql]
#编码
default-character-set=utf8 

4. Install mysql database

Enter cmd to run as an administrator

and enter the bin directory of the installation

Enter mysqld -install
the installation is successful
Enter to net start mysql
start the database
Enter the command mysql -u root -p, do not need to enter a password, just press Enter Enter
the command line use mysqlto enter the database
Enter the command line update user set authentication_string=password("xxxxxx") where user="root";xxxxxx is the new password you set,
and the installation operation is complete at this step

2. Common operations of Mysql database

library operation

1. database login

mysql -u root -p

2. View all current databases

show databases;

3. create a database

create database 数据库名 DEFAULT CHARSET utf8 COLLATE utf8_general_ci;
create database 数据库名 DEFAULT CHARSET 编码 COLLATE 排序规则

4. drop a database

drop database 数据库名;

5. enter the database

use 数据库名;

6. View all tables under the database

show tables

table operation

1. create a table

create table text（表名）(
	id（属性名） int not null auto_increment primary key , --不允许为空&主键&自增
	name varchar(16) not null , 		--不允许为空
	email varchar(32) null,			--不允许为空（默认）
	age int default 3 				--插入数据时，如果不给age列设置值，默认值为3
	) default charset=utf8;

Note: There can only be one auto-increment column in a table, which is generally the primary key

2. delete table

drop table 表名 ;

3. empty table

delete from 表名;
truncate table 表名;(速度快，无法回滚撤销等)

4. modify table

   1. add column

   alter table 表名 add 列名 类型
   alter table 表名 add 列名 类型 default 默认值;
   alter table 表名 add 列名 类型 not null default 默认值;
   alter table 表名 add 列名 类型 not null primary key auto_increment
   

   2. delete column

   alter table 表名 drop column 列名;
   

   3. modify column

   alter table 表名 modify column 列名 类型;
   alter table 表名 change 原列名 新列名 新类型;
   alter table 表名 alter 列名 set default 1000;