The database organizes, stores and manages data according to the data structure. It is a warehouse built on the computer storage device.
Simply speaking, it can be regarded as an electronic file cabinet itself - the place where electronic files are stored. Users can add, intercept, update and delete data in files.
1. Install and deploy http://www.daiqiyang.com
#The database is already installed by default, if not, use the following command to install it
[root@mail ~]# yum install -y mariadb
#Start the database service
[root@mail ~]# systemctl restart mariadb
#Initialize the database
[root@mail ~]# mysql_secure_installation First direct return here: Set the password for the root of the database: Later, do some initialization settings, generally Y is OK.
#Add Permanent Allow Policy to Firewall
[root@mail ~]# firewall-cmd --permanent --add-service=mysql
#Reload Firewall Configuration
[root@mail ~]# firewall-cmd --reload
2. Landing Use
#Database System Logon
[root@mail ~]# Mysql-uroot-predhat //Note that there is no space between command and parameter here [root@mail ~]# Mysql-uroot-p //so login can hide password [root@mail ~]# mysql -u root -h localhost -p [DATABASE NAME]
-u: The user name to connect to the mysql server;
-h: ip address or hostname of mysql server;
-p: Password to connect to mysql server;
#See how many databases your system has
MariaDB [(none)]> show databases; //Commands in the database end with;
#Exit the database system
MariaDB [(none)]> quit MariaDB [(none)]> exit
#Create a database
MariaDB [(none)]> create database luntan;
#Switch to a database
MariaDB [mysql]> use mysql;
#View tables in the database
MariaDB [mysql]> show tables;
#View the table structure of the data table
MariaDB [mysql]> desc user;
#Query some data in the user table
MariaDB [mysql]> select host,user,password from user;
#Create a table
MariaDB [mysql]> create table person ( -> number int(11), -> name varchar(255), -> birthday date);
#Table structure of table created by query
MariaDB [mysql]> desc person;
#Insert several pieces of data
MariaDB [mysql]> insert into person (number,name,birthday) values (1,"haha",20191225); MariaDB [mysql]> insert into person (number,name,birthday) values (2,"xixi",20191226); MariaDB [mysql]> insert into person (number,name,birthday) values (3,"hehe",20191227);
#Query table contents
MariaDB [mysql]> select * from person;
#Delete table contents
MariaDB [mysql]> delete from person where name="haha"; MariaDB [mysql]> delete from person where number=3;
#Update data in tables
MariaDB [mysql]> update person set name="haha" where name="xixi"; MariaDB [mysql]> update person set number=1 where birthday=20191226;
3. User management and control of access rights
Create Database Logon User
MariaDB [mysql]> create user xiaoming@localhost identified by 'redhat'; MariaDB [mysql]> create user xiaohong@localhost identified by "redhat"; MariaDB [mysql]> select host,user,password from user;
View current users:
MariaDB [(none)]> select user();
View the current user's database:
MariaDB [(none)]> select database();
Use Xiaoming user to log in to the database:
[root@localhost ~]# mysql -u xiaoming -p
#View accessible databases
MariaDB [(none)]> show databases;
#Permissions to log in as root to a table for the xiaoming user
MariaDB [(none)]> grant select,update,insert,delete on mysql.person to xiaoming@localhost;
Exit the database system and log back in using the xiaoming user
[root@localhost ~]# mysql -u xiaoming -p MariaDB [(none)]> use mysql;
#Test various permissions
MariaDB [mysql]> select * from person; MariaDB [mysql]> insert person (number,name,birthday) value (3,"xiaoming",20181228); MariaDB [mysql]> update person set name="xixi" where number=1 MariaDB [mysql]> delete from person where number=1;
#Change the permissions of the xiaoming user by logging in with the root user
MariaDB [(none)]> revoke delete on mysql.person from xiaoming@localhost;
#Use the select statement to delete table data and confirm that permissions are disabled
MariaDB [mysql]> delete from person where number=3 ;
IV. Backup and Restore
Back up all tables of the entire database
[root@mail ~]# MySQL dump-u root-p MySQL >/mysql_backup_20160510.dump // Make a backup file in a location of your choice
#Log in to the database using the root user and delete the person table
MariaDB [mysql]> drop table person;
#Exit the system for restore
[root@mail ~]# mysql -u root -p mysql < /mysql_backup_20160510.dump
Or use the source command to read table information.
#Log on to the database system
[root@mail ~]# mysql -u root -p
#View person table
MariaDB [mysql]> select * from person;
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Copyright Statement: This is an original article by CSDN blogger "Pessimistic Optimist", which follows the CC 4.0 BY-SA copyright agreement. Please attach a link to the original source and this statement.
Original Link: https://blog.csdn.net/weixin_43997530/article/details/103634828