Introduction to mysql
MySQL is a relational database management software. The characteristic of relational databases is to store data in different two-dimensional tables. The most commonly used standardized language for accessing and managing MySQL databases is SQL structured query language.
1. MySQL installation
There are many ways to install mysql, the simplest and most suitable is the binary method installation. Next, we use the mysql binary package to install and deploy mysql
Unzip software
- tar xf mysql-5.6.35-linux-glibc2.5-x86_64.tar.gz -C /data1/server/
- cd /data1/server/
- ln -s mysql-5.6.35-linux-glibc2.5-x86_64 mysql
Create a dedicated user
- useradd -s /sbin/nologin -M mysql
Initialize the mysql database
- /data1/server/mysql/scripts/mysql_install_db --basedir=/data1/server/mysql --datadir=/data1/server/mysql/data1/ --user=mysql
Related configuration files
Database configuration file management
- mv /etc/my.cnf /etc/my.cnf-bak
- cp /data1/server/mysql/support-files/my-default.cnf /etc/my.cnf
Database startup command configuration (simultaneously copied to the input command)
- cp /data1/server/mysql/support-files/mysql.server /etc/init.d/mysqld
- chmod +x /etc/init.d/mysqld
Start file modification
- sed -i 's#/usr/local/mysql#/data1/server/mysql#g' /data1/server/mysql/bin/mysqld_safe /etc/init.d/mysqld
After the file is modified, enter cat /etc/init.d/mysqld and modify the path to / data1 / server / mysql
Database file permission management
- chown -R mysql.mysql /data1/server/mysql/
Detailed explanation of sed file content modification commands (simpler than vim command editing content):
Start the database
Check before starting the database
- netstat -tnulp | grep mysql
Start the database
- /etc/init.d/mysqld start
Check the database startup status
- netstat -tnulp|grep mysqld
Configure environment variables
- vim /etc/profile
# Add this configuration at the end (the role is to add all commands of mysql to all command paths)
- PATH=/data1/server/mysql/bin:$PATH
Make the configuration file effective
- source /etc/profile
At this point, the mysql installation is complete: test whether the installation is successful, directly enter the mysql command
Database command operation
- show databases; <--- query the default database information
Choose to use a database
- use mysql; <--- means to choose to use a database, which is equivalent to CD entering a database
View the current database
- select database (); <--- means to view the current database, similar to the function of pwd command
View the user currently logged in to the database
- select user (); <--- view the user currently logged in to the database, similar to the whoami command and mysql can also restrict where the specified user can connect to log in to the database
View the directory where you can log in to the mysql database
- select user, host from mysql.user; --- View the directory where you can log in to the mysql database, and where you can manage the mysql database
Create a database
- create database database name; ===> can create a database
Via show databases; view
Create a user for the specified database
The user who created a database:
- grant all on iwebshop.* to 'iwebshop'@'localhost' identified by '123456';
- grant all on database name. * to 'database login user name' @ 'database login host' identified by 'password';
#Create a user wordpress with permissions of all, and set the network segment that allows login, and finally set the password
After creating a user, update the database information flush privileges;
- mysql> flush privileges; refresh privileges
- #flush privileges After creating users, update the database information
View the user information of the database select user, host from mysql.user;
Delete a database
- drop database database; ===> can delete a database, through show databases; view
