Mysql/en

Mysql is a handy database which is easy to manage using the phpmyadmin application. Using phpmyadmin requires HTTP server software as well for instance Apache2 or Nginx and Php5.

Installation

 aptitude install mysql-server

Give the mysql root user login password in installation. Do not forget the password. You can create more user accounts and change passwords later.

You can also use a mysql database without phpmyadmin but it helps a lot with managing it.

aptitude install mysql-client

• 

  Give password for MySQL server root user

• 

  Repeat root user password

MySQL configuration

Configuration file can be found in Ubuntu and Debian under:

 /etc/mysql/my.cnf

The port the MySQL server listens to. By default it is set to 3306.

[client]
port 3306

Address the server will listen to. Put a # number sign in front of the line and it will listen to all IP addresses.

bind-address               = 127.0.0.1

Command Line

Mysql databases can also be managed by command line.

You can connect to a mysql server with command line by:

 mysql -u root -p

Give the mysql root user password.

User Accounts

List user accounts:

  select host, user, password from mysql.user;

You can create a new user account with the command:

 CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';

Give privileges for the new user account. The following command gives pretty much all privileges except the ones for modifying user accounts.

 GRANT ALL PRIVILEGES ON * . * TO 'newuser'@'localhost';

This command gives the user all privileges including databases and users accounts.

 GRANT ALL PRIVILEGES ON * . * TO 'newuser'@'%' WITH GRANT OPTION;

Confirm privileges:

 FLUSH PRIVILEGES;

Add certain privileges to a user account:

GRANT [type of permission] ON [database name].[table name] TO ‘[username]’@'localhost’;

Remove certain privileges from a user account:

 REVOKE [type of permission] ON [database name].[table name] FROM ‘[username]’@‘localhost’;

Remove user account:

  DROP USER ‘demo’@‘localhost’;

Master and Slave

Asynchronous synchronization of a MySQL server from Master server to Slave servers.

Master

This goes in the Master server's configuration:

 nano /etc/mysql/my.cnf

Add these to the end of mysqld

[mysqld]
...
log-bin=mysql-bin
server-id	= 1
auto_increment_increment = 10
auto_increment_offset = 1

Form connection to MySQL server:

mysql -u root -p

We create the user account replicant, with login rights from wherever % and password is just "password"

 create user replicant@'%' identified by 'password';

Define privileges for the user:

 GRANT SELECT, PROCESS, FILE, SUPER, REPLICATION CLIENT, REPLICATION SLAVE, RELOAD ON *.* TO replicant@'%';
 Flush Privileges; 

Slave

This goes in the Slave server's configuration:

Establish a connection to the database server and give the Master server's IP-address, username and password.

HANGE MASTER TO
MASTER_HOST='10.10.10.100',
MASTER_USER='replicant',
MASTER_PASSWORD='password';

Käynnistä Slave palvelin

Start slave;

Varmista että kaikki toimii:

show slave status\G

Molempiin suuntiin synkroidessasi, sinun tulee määrittää molemmat palvelimet Slaveksi ja Masteriksi.

MYSQL ja PHP5

Voit hakea ja lähettää MySQL tietokantaan tietoa PHP:n avulla. Tämä onnistuu yksinkertaisesti tälläisellä funktiolla:

 <?php
 mysqli_connect(host,username,password,dbname);
 mysqli_close($con);
 ?>

Muokkaa tätä esimerkiksi:

 <?php
 //Muodostetaan yheyttä tietokantaan
 $con = mysqli_connect(127.0.0.1,root,Qwerty123,database);
 //Suljetaan yhteys tietokantaan
 mysqli_close($con);
 ?>

Eli palvelimen osoite, käyttäjätunnus, salasana ja tietokanta joka valitaan.

MySQL tietokannasta tulostaminen

 <?php
 $con=mysqli_connect("127.0.0.1","root","Qwerty123","database");
 if (mysqli_connect_errno()) {
 echo "Yhdistäminen epäonnistui " . mysqli_connect_error();
 }
 $result = mysqli_query($con,"SELECT * FROM data");
 while($row = mysqli_fetch_array($result)) {
 echo $row['mysql'];
 }
 mysqli_close($con);
 ?>

Huomaa, että tietokantaan täytyy kirjoittaa jotakin että voit tulostaa tietoa sieltä.

Talllenna edelliset konfiguroinnit mysql.php ja laita sitten esim. index.php tiedostoon:

 <?php
 include_once ('mysql.php');
 ?>

Näin sinun täytyy laittaa kaikkiin haluamaasi php tiedostoon, jotka käyttää tietokantaa.

Varmuuskopio

Automysqlbackup

Lähteet

https://www.digitalocean.com/community/tutorials/how-to-create-a-new-user-and-grant-permissions-in-mysql