View source for Database - MariaDB

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Something to note: When working with MariaDB, you will occasionally see utilities & such referring to mySQL.  This is normal as MariaDB is a replacement for mySQL & the developers have not recreated things that work for both. (in many cases, this means that commands you would expect to be based on '''mariadb''' will be '''mysql''' instead.)

= Installation =

* <code>sudo apt install mariadb-server mariadb-client php-mysql</code>

= Initial Configuration =

* <code>sudo mysql_secure_installation</code>

<pre style="color: rgb(22, 145, 121);">
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, we'll need the current
password for the root user. If you've just installed MariaDB, and
haven't set the root password yet, you should just press enter here.

Enter current password for root (enter for none): 
</pre>

Press '''Enter'''

<pre style="color: rgb(22, 145, 121);">
OK, successfully used password, moving on...

Setting the root password or using the unix_socket ensures that nobody
can log into the MariaDB root user without the proper authorisation.

You already have your root account protected, so you can safely answer 'n'.

Switch to unix_socket authentication [Y/n]
</pre>

Select '''N'''

<pre style="color: rgb(22, 145, 121);">
 ... skipping.

You already have your root account protected, so you can safely answer 'n'.

Change the root password? [Y/n] 
</pre>

Select '''N'''

<pre style="color: rgb(22, 145, 121);">
 ... skipping.

By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] 
</pre>

Select '''Y'''

<pre style="color: rgb(22, 145, 121);">
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] 
</pre>

Select '''Y'''

<pre style="color: rgb(22, 145, 121);">
 ... Success!

By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] 
</pre>

Select '''Y'''

(Don't think I've EVER used the test database... EVER...)

<pre style="color: rgb(22, 145, 121);">
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] 
</pre>

Select '''Y'''

This is a silly question.

<pre style="color: rgb(22, 145, 121);">
 ... Success!

Cleaning up...

All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!
</pre>

= Allowing non-localhost access =
By default, MariaDB (like MySQL) binds to 127.0.0.1...

This is ugly, but works for now:

* <code>sudo vi /etc/mysql/mariadb.conf.d/50-server.cnf</code>
& change

<code>bind-address              = 127.0.0.1</code>

to

<code>bind-address              = '''Machine.Domain.TLD'''</code>

(where '''Machine.Domain.TLD''' is the FQDN or IP address of the database server itself...)

= Set up at least one database user =

* <code>sudo mysql -u root</code>
<pre>
CREATE USER 'someone'@'localhost' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;
EXIT;
</pre>

('''Hint:''' This'd be a good time to create yourself as that user with your non-admin password of choice...)

If this is to be a remotely accessed Database Server, ''''localhost'''' will actually be the name/address of the remote machine you'll access '''from'''. (Possibly even ''''*'''' as a wildcard)

= Some Reference Materials =

*[https://www.w3schools.com/sql/default.asp SQL Tutorial]
*[http://g2pc1.bu.edu/~qzpeng/manual/MySQL%20Commands.htm Commands]
*[https://www.freecodecamp.org/news/basic-sql-commands/ Basic SQL Commands - The List of Database Queries and Statements You Should Know]
*[https://linuxize.com/post/how-to-manage-mysql-databases-and-users-from-the-command-line/ How to Manage MySQL Databases and Users from the Command Line]
*[https://www.hostinger.com/tutorials/?s=mysql Some handy tutorials]
**[https://www.hostinger.com/tutorials/mysql-show-users/ How to Show Users in MySQL on Linux]

= Some Useful Things =

*Sign into MySQL
**<code>sudo mysql -u root -p</code>
*Restart MySQL
**<code>sudo systemctl restart mysql.service</code>
*Change a user password
**<code>ALTER USER 'userName'@'localhost' IDENTIFIED BY 'New-Password-Here';</code>
*Create a new database
**<code>CREATE DATABASE db_name;</code>
*Trash a complete database '''(WARNING! DANGER! DAMAGE LIKELY!)'''
**<code>DROP DATABASE wp_Someblog;</code>
*List existing databases
**<code>SHOW databases;</code>
*List existing users
**<code>SELECT user,host FROM mysql.user;</code>

==Move a database from one server to another==

===On the originating server:===

*<code>sudo mysql -u root -p</code>
**<code>GRANT ALL ON *.* TO 'user'@'localhost';</code>
**<code>FLUSH PRIVILEGES;</code>
**<code>EXIT;</code>

*<code>mysqldump -u user -p DBname > DBname.sql</code>
*<code>scp DBname.sql user@Machine.Domain.TLD:~</code>

===On the destination server:===
Create the user & database (following the instructions for the application requiring the database)

*<code>mysql -u user -p DBname < DBname.sql</code>

===If using a separate DB Server...===
Create the user & database on the DB Server, then log onto the application server &do the following

(You may have to backtrack & SCP the file to the application server...  :P )

*<code>mysql -u user -p -h Machine.Domain.TLD DBname < DBname.sql</code>