Uninstall MySQL server

To get started, run these commands as root or use sudo

service mysql stop
apt-get remove mysql-server mysql-common libmysqlclient18

Install MariaDB

Run the following command

apt-get install software-properties-common

Add MariaDB Store Key

sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xcbcb082a1bb943db

Add MariaDB Repository

sudo add-apt-repository 'deb http://ftp.utexas.edu/mariadb/repo/10.0/ubuntu trusty main'

Install MariaDB

apt-get install mariadb-server libmariadbclient18

Handling Unsatisfied Dependencies

The MariaDB installer may fail (which often happens) with an error, such as this one:

mariadb-server : Depends: mariadb-server-10.0 (specific version) but it is not going to be installed.

This can be frustrating and may not look right. Next, you need to install all the adjacent dependencies. Add g ++ repository to server to resolve libstdc ++ 6 dependency.

Add g ++

add-apt-repository ppa:ubuntu-toolchain-r/test
apt-get update
apt-get install g++-4.9

Pin the MariaDB repository

This is done by creating a file with MariaDB.pref in /etc/apt/preferences.d/ with the contents shown below:

Package: *
Pin: origin <mirror-domain>
Pin-Priority: 1000

Replace the <mirror-domain> that is displayed when accessing the MarizDB repository selection page

In my case, I chose the “University of Dallas”. After updating, the file now has the following contents:

Package: *
Pin: origin http://ftp.udallas.edu/mariadb/repo/10.0/ubuntu
Pin-Priority: 1000

Save the file, upgrade your system.

apt-get update

Now, dependency problems have been resolved. If you use 12.04, then pay attention to the fact (it is important) that there were reports that g ++ was excluded from this version.

Install MariaDB again

apt-get install mariadb-server

Check your installation of MariaDB

service mysql start
mysql -u root -p

Now, you can see the following (or the same) output

Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is XXXX
Server version: 10.0.X


Copyright (c) 2000, 2014, Oracle, Monty Program Ab and others.


Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]>

Substring is a special function that is used to return or extract a string from strings in any table. The general syntax looks like this:

SUBSTRING(string, start, length)

In order for you to understand this function, you can take a table as an example and use the following commands to extract rows from it. We will open a terminal and type “mysql” to enter the MySQL environment.

sudo mysql

Next, you should open the list of databases, all that you currently have in MySQL

show DATABASES;

Next, you should open a database, for example with the name “sample database”:

SHOW TABLES;

In the output, we can see that the company database contains only one table named “Hello_World_from_here“. We will now access this table to display its contents:

DESCRIBE Hello_World_from_here

We can now display the contents of the table:

SELECT * FROM Hello_World_from_here

We say that we want to extract the string “Hello” from the table using the Substring function, then we will use the code according to the syntax we discussed above, and we will use “AS ExtractString” to return a value in the form of a string from the table …

SELECT SUBSTRING(employee_name, 1, 5) AS ExtractString FROM Hello_World_from_here;

This command is used as a terminal. This is necessary in order to fetch a row from a column named employee_name, start at the first character, and extract the next 5 characters. To understand this better, let’s say we want to extract 2 characters from the column named World_from_here, but it starts at the third character, so the command will be.

SELECT SUBSTRING(World_from_here, 1, 5) AS ExtractString FROM Hello_World_from_here;\

This output will deal with extracting only “dr” and “xi”. In addition, a command will be run to retrieve the string.

SELECT SUBSTRING(“Hello”, +3, 2) AS World_from_here;

So, what happened in the latest changes.

The terminal was requested to use a special MySQL function that returns string characters from the string “World” and starts at its third position from the start point, the + ve sign tells it to start at the start point and extract the next two characters. So, in the line “World”, if we start at the third position from the starting point, it will start with “d”, and if we extract two characters next to it, then it will be “dr”

Now, at the moment, you need to run the following command. This will now allow you to extract “ax” from the string “Maxim” using a starting point at the end of the string.

SELECT SUBSTRING(“Maxim”, -4, 2) AS World_from_here;

The syntax for using the nysqldump command to export a database is. This shows us the following:

Access to the username database;

Mysqldump may ask you for a password;

Following are the processes that will tell us about backing up databases to an SQL file named name.sq

Restore your database

Primarily! If something went wrong for you, you can easily restore your database. Log in to get started

mysql -u username -p

Then create a new database

CREATE DATABASE newdb;

Quit MySQL

exit

After that, you can import the SQL file into a new database

mysql -u username -p newdb < name.sql

This completes the process of importing your SQL file into a new database!

Backup process

We recommend a way to back up a MySQL or MariaDB database using the mysqldump dump command.

echo "SHOW DATABASES;" | sudo mysql

This command displays a list of your databases. Make sure you know which .sql file you need, and then simply run the following command to backup to the file.

sudo mysqldump example_database > $(date +"%F").sql

The command described above will back up the example_database to a file with a date ending in .sql. It is also possible to change the name of this file to any other, although saving the file name as a date will be useful if you accidentally delete an important row or column. Use date –help to learn about other ways to style your date.

Recovery

Here you need to find the .sql file that you created and run the following:

sudo mysql example_database < filename.sql

Migrating to MariaDB from MySQL

The first thing to do is back up each of your databases:

sudo mysqldump example_database > example_database.sql

After that, you will need to install MariaDB, which will replace MySQL, and restore your databases by following these steps for each database.

sudo mysql example_database < example_database.sql

mysql - V

Check for the latest up-to-date database version. If it is, then proceed to the step of checking the status of the system mysql.service. To do this, run the following command:

sudo systemctl status mysql

If the service is not active, start the service

sudo systemctl start mysql

After starting the service, connect to the MySQL client or log into the MySQL shell as the root user. If you do not have access to the root user account, replace “root” with your username

sudo mysql -u root -p

After logging into MySQL, list the databases with SHOW DATABASES command:

SHOWDATABASES;

After you have a list of databases, then you need to select the database in which you want to delete. If you want to drop an existing database, you can run a simple DROP DATABASE command along with the database name like this:

DROPDATABASE your_database_name;

After deleting the database, you need to list the databases again, for this use the SHOW DATABASES command

SHOWDATABASES;

Now it is possible to notice that the remote database no longer exists in MySQL.

1. Add to my.cnf file forever

vim /etc/my.cnf 
log = /home/general-query.log

Install via MySQL Console

SET general_log = 1;

Start server

systemctl restart mysqld

2. Add to my.cnf file permanently or include general queries for MySQL on versions higher than 5.1.29

general_log_file = /path/to/general-query.log

general_log = 1

Install via MySQL Console

SET general_query_log = 1;

Then create the general-query.log file in which you want to store these logs

touch general-query.log

chown -R mysql:mysql general-query.log

systemctl restart mysqld

Done! You have now successfully enabled the general MySQL query log on Linux.

First, update the apt package index with the command:

sudo apt update

Then install the package:

sudo apt install mysql-server

This command will install MySQL, then basic MySQL configuration is required

Configure MySQL

Run the security script with:

sudo mysql_secure_installation

As you can see, security is at the plinth level. At least there is no anonymous user. To configure the basic things in the server, run the server configuration through mysql_secure_installation. At the time of this installation, the password will be security. Your same password, as you know, should be different

/usr/bin/mysql_secure_installation

Skip root password for root

We haven’t set the root password yet, so when you run the script and ask for the root password, just press Enter. Install new password for root: security, and here you can set the password for root. Do remove an anonymous user. When asked whether to remove an anonymous user, answer Yes

Do not disallow remote connections. Do not prohibit the connection to our North from remote servers (if, of course, this option you need, in other case, prohibit it). Do remove a test database. Test base we do not need – remove it. Do reload the privileges. Overload privileges to activate them

The password is now set for all root users. If you did not set a root password during this configuration, you can do so as follows:

SET PASSWORD FOR 'root'@'localhost' = PASSWORD('security');

SET PASSWORD FOR 'root'@'localhost.localdomain' = PASSWORD('security');

SET PASSWORD FOR 'root'@'127.0.0.1' = PASSWORD('security');

or

UPDATE mysql.user SET Password = PASSWORD('security') WHERE user = 'root';

If you did not run the configuration through mysql_secure_installation or do not want to do so for some other reason, the following commands will remove any users:

DROP USER "@'localhost';

DROP USER "@'localhost.localdomain';

Also, the password for IPv6 localhost (@::1) can be set this way:

SET PASSWORD FOR 'root'@'::1' = PASSWORD(<password>);

The final of our action is coming. There are two things. Open the ports for mysql:

sudo iptables -I INPUT -p tcp --dport 3306 -m state --state NEW,ESTABLISHED -j ACCEPT

sudo iptables -I OUTPUT -p tcp --sport 3306 -m state --state ESTABLISHED -j ACCEPT

Set the default UTF-8 encoding to /etc/my.cnf

[mysqld]

init_connect=‘SET collation_connection = utf8_unicode_ci’

character-set-server = utf8

collation-server = utf8_unicode_ci

[client]

default-character-set = utf8

Overloading the service:

sudo service mysqld restart

Conclusion

mysqld: can't create directory '/var/lib/mysql/' (Errcode: 17 - File exists)

. . .

2019-07-15T14:30:25.572066 Z 0 [ERROR] Abortion

Note that although you have set a password for The MySQL root user, this user is not configured for password authentication when connecting to the MySQL shell.

Check if the service started:

systemctl status mysql.service

mysql.service – MySQL Community Server

Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: en

Active: active (running) since Mon 2019-07-15 14:30:25 UTC; 30min ago

Main PID: 3754 (mysqld)

Tasks: 28

Memory: 149.3 M

CPU: 2.094 s

CGroup: /system.slice/mysql.service

7875 /usr/sbin/mysqld

Optional configure authentication and privileges

On servers running Ubuntu that use MySQL 5.7 (and later), the MySQL root user is authenticated by default using the auth_socket plugin, not by password. This is generally more secure and convenient in many cases, but not when you need to organize access to MySQL from a third-party program, for example, phpMyAdmin.

In order for the MySQL root user to be able to use the login password, you need to change the authentication method from auth_socket to mysql_native_password. To do this, enter the MySQL shell with the following command:

sudo mysql

Next, check which authentication method is used for each of your MySQL users. SELECT user,host,authentication_string,plugin FROM mysql.user. Like this you can see

+------------------+-----------+-------------------------------------------+-----------------------+

| user | host | authentication_string | plugin |

+------------------+-----------+-------------------------------------------+-----------------------+

| root | localhost | | auth_socket |

| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password |

| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password |

| debian-sys-maint | localhost | *CC744277A401A7D25BE1CA89AFF17BF607F876FF | mysql_native_password |

+------------------+-------------------------------------------+-----------------------+-----------+

4 rows in set (0.00 sec)

The string auth_socket means that the user will be able to connect without entering a password when connecting via a local UNUX socket. If you are not satisfied with this behavior of MySQL, enter the following command in the mysql console.

> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'VERY_VERY_SECURE_PASSWORD';

Naturally VERY_VERY_SECURE_PASSWORD replace really safe, known only to those who should know it

> FLUSH PRIVILEGES;

Check yourself! SELECT user,host,authentication_string,plugin FROM mysql.user. Like this you can see

+------------------+-----------+-------------------------------------------+-----------------------+

| user | host | authentication_string | plugin |

+------------------+-----------+-------------------------------------------+-----------------------+

| root | localhost | *8C744276549879874FC098CABFF17BF607F876FF | mysql_native_password |

| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password |

| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password |

| debian-sys-maint | localhost | *CC744277A401A7D25BE1CA89AFF17BF607F876FF | mysql_native_password |

+------------------+-------------------------------------------+-----------------------+-----------+

4 rows in set (0.00 sec)

For verification:

• Exit the mysql client (ctrl+d or write exit) if you are in it;
• As root, type mysql or (sudo mysql) as another user.

Mysql program should ask for a password if you log in without a password recheck the steps. Add a local tommy superuser with full database access and the right to assign rights to other users:

> GRANT ALL PRIVILEGES ON *.* TO 'tommy'@'localhost' WITH GRANT OPTION IDENTIFIED BY 'VERY_SECURE_TOO_PASSWORD';

Adding user jonny connecting with IP 123.45.67.89 to work with WORDPRESS database:

> GRANT ALL PRIVILEGES ON *.WORDPRESS TO 'tommy'@'123.45.67.89' IDENTIFIED BY 'OTHER_VERY_SECURE_PASSWORD';

Apache installation

First of all (as with any other installation of programs), you need to update the package manager

sudo apt-get update -y

Install and start Apache

sudo apt-get install apache2 -y
sudo systemctl start apache2.service

It is important to make sure that Apache was installed correctly and without errors. To do this, enter hostname -I in order to get your IP address and go to the link http:// SERVER_IP/

MySQL installation

sudo apt-get install mysql-server -y

This command will install the MariaBD database server and will then be prompted to enter the password for the root MySQL user. This step is required.

Install PHP

You can install PHP using the following command:

sudo apt-get install php -y

After installing PHP, you need to install common PHP extensions, such as GD, MySQL, and so on, using the following command:

sudo apt-get install -y php-{bcmath,bz2,intl,gd,mbstring,mcrypt,mysql,zip} && sudo apt-get install libapache2-mod-php  -y

Automatically Starting Apache and MySQL on Boot

These commands will allow you to start Apache and MySQL always when loading your web environment

sudo systemctl enable apache2.service
sudo systemctl enable mysql.service

Next, restart the Apache server for PHP to work

systemctl restart apache2.service

apt update

It is recommended that you install the snapd package for Workbench to work properly. This can be installed by running the following command:

apt install snapd

Install the kernel files using Snap by running the following command:

snap install core

Now, to install MySQL Workbench using Snap, run the following command:

snap install mysql-workbench-community

Once installed, you can find MySQL Workbench in the application finder, or in the applications menu. In Debian 11, you will see a warning that the operating system is not supported. MySQL Workbench currently supports the following operating systems: Ubuntu, Red Hat Enterprise, Oracle Linux, Fedora, and Microsoft Windows. The fact that your system is not officially supported can be ignored, and this does not mean that you will run into errors. However, below I decided to add some Linux compatible alternatives to MySQL Workbench. More information on MySQL Workbench can be obtained at this link.

Copying your data from the Ubuntu server

First, you need to be logged in as a user with root privileges. After successful login, you need to check the list of databases. This can be done by entering a simple command:

mysql -u USERNAME

Further, after a successful login, you need to enter a special command that will provide you with the entire list of databases. This command looks like this:

SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| test_data          |
| important_db       |
| information_schema |
| mysql              |
| performance_schema |
+--------------------+
5 rows in set (0.012 sec)

Then you can close the command line by typing exit;

Using Mysqldump

You may need to use a password for login. To do this, just add -p to the command below. If you need to keep all databases, you can use the shortcut –all-databases instead of –databases names

mysqldump -u USERNAME --databases test_data important_db > database_dump.sql

Then the file is automatically generated. It will be named “database_dump.sql”. Its content includes all data for restoring the databases that you specify.

Protecting Your Backup Process

An important recommendation: if the data in the database contains sensitive data, then you should definitely encrypt it before you save or start the process of moving between servers. Run the first command below and then enter your password; it will not appear on your screen.

openssl enc -aes-256-cbc -pbkdf2 -in database_dump.sql -out database_dump.sql.enc
  enter aes-256-cbc encryption password:
  Verifying - enter aes-256-cbc encryption password:


rm database_dump.sql

In order for you to be able to decrypt your backup, you can use a special command, which is indicated below:

openssl enc -d -aes-256-cbc -pbkdf2 -in database_dump.sql.enc -out database_dump.sql
  enter aes-256-cbc encryption password:

The process of moving a backup

During the backup process, the .sql size can be bulky in size. This will negatively affect the file and data transfer process. Instead, you can use tools such as rsync to exchange data directly between servers.

rsync -a ./database_dump.sql user@185.186.244.123:/tmp/

185.186.244.123 – should be changed to your server address
user is the username on the remote server
tmp/ – should be replaced with your remote server directory

To restore your database, you can use the special mysql utility, an example is shown below:

mysql -u USERNAME <database_dump.sql