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;

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';

Install MongoDB Community Edition

Install MongoDB Database using CentOS Package Installation Manager – yum. First, you need to create a file /etc/yum.repos.d/mongodb-org-4.4.repo for this database

# nano /etc/yum.repos.d/mongodb-org-4.4.repo

Then paste into your text editor what is described below:

[mongodb-org-4.4]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/4.4/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-4.4.asc

Save this and then you can close your text editor. After that, if you want to install the latest, stable and current version of MongoDB, you need to enter the following:

# sudo yum install -y mongodb-org

Configuring MongoDB

At this stage, the installation of this Database is completed. Now you need to configure it. To do this, you must first start MongoDB

# systemctl start mongod.service
# systemctl enable mongod.service

Next, connect to MongoDB

# mongo

MongoDB is insecure by default. You can follow this link to configure security and authentication of this Database.

If you need to install a specific version or prevent automatic updates, you can see the MongoDB documentation.

Update the package repository

\Before installing MongoDB, you need to make sure everything is up to date. This can be done by running the following command accordingly:

pkg update

There may be the following message stating that “package management tool” is not available, type Y, press Enter to continue. You can run pkg update -f a forced update if needed. If unsuccessful, go to step 2 – Installing MongoDB

Installing MongoDB

Install MongoDB using the following command:

pkg install mongodb

Start and Test The Installation of MongoDB

Check your MongoDB installation. This command will start the service:

service mongod onestart

The consol’ll look loke this:

MongoDB shell version: 4.4
connecting to: test
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
    http://docs.mongodb.org/
Questions? Try the support group
    http://groups.google.com/group/mongodb-user

Turn the MongoDB at each boot

If you don’t want to use “onestart” to start Mongo on boot, you can configure it to run start instead. To do this, you need to edit /etc/rc.conf. with vi or any other text editor and add mongod_enable = “YES” to the file. Once finished, it will start when your server boots up and you can now use its service mongod start to start the Mongo service. Other service commands such as stop and status will also be available.

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You can install MySql Workbench using a simple program, which will be described below. An important factor is that the package is part of the official Ubuntu repository. The official name of the package is MySQL-workbench, you can install it as follows:

apt-get install mysql-workbench

Then the step that must be completed: then you should go to the main menu and click the MySQL workbench start icon to start the program. The main page will appear after starting the program.

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.

Add MongoDB Public Key

This command adds the GPG MongoDB public key to the system key list:

apt-key adv --keyserver keyserver.ubuntu.com --recv 7F0CEB10

This key is necessary in order to ensure the consistency and authenticity of all packages.

Add MongoDB Storage

First you need to create the mongodb.list file to add the MongoDB repository to the system. You can do this with the following command:

echo "deb http://repo.mongodb.org/apt/debian "$(lsb_release -sc)"/mongodb-org/3.0 main" | tee /etc/apt/sources.list.d/mongodb-org-3.0.list

Package Updates

To get information about the latest packages, please nter the command:

apt-get update

Install MongoDB packages

To install the latest stable version of MongoDB, use the following command:

apt-get install -y mongodb-org

• mongodb-org-server
• mongodb-org-mongos
• mongodb-org-shell
• mongodb-org-tools

*Here are 4 packages that mongodb-org automatically install

Launch MongoDB

After installation is complete, MongoDB starts automatically. If you need to manually start the MongoDB server, use the following command:

service mongod start

To stop and restart mongodb processes, use this commands:

service mongod stop

service mongod restart

You can access the MongoDB shell by running the following command: (this allows you to connect to the MongoDB server)

mongo

When the shell starts, you will see the output in the following format:

MongoDB shell version: 3.0.0
connecting to: test
>