MySQL Installation on CentOS/Redhat

Install and Start MySQL

1. Install MySQL and tell it which runlevels to start on:
   

   yum install mysql-server /sbin/chkconfig --levels 235 mysqld on

2. Then to start the MySQL server:
   

   service mysqld start

   MySQL will bind to localhost (127.0.0.1) by default.
   

Allowing unrestricted access to MySQL on a public IP not advised, but you may change the address it listens on by modifying the bind-address parameter in /etc/my.cnf. If you decide to bind MySQL to your public IP, you should implement firewall rules that only allow connections from specific IP addresses.

Harden MySQL Server

1. Run the mysql_secure_installation script to address several security concerns in a default MySQL installation.
   

   mysql_secure_installation

You will be given the choice to change the MySQL root password, remove anonymous user accounts, disable root logins outside of localhost, and remove test databases. It is recommended that you answer yes to these options.

Using MySQL

The standard tool for interacting with MySQL is the mysql client which installs with the mysql-server package. The MySQL client is used through a terminal.

Root Login

1. To log in to MySQL as the Root User:
   

   mysql -u root -p

2. When prompted, enter the root password you assigned when the mysql_secure_installation script was run.
   You’ll then be presented with the MySQL monitor display:
   

   1 2 3 4 5 6 7

   Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 Server version: 5.0.45 Source distribution Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql>

3. To generate a list of commands for the MySQL prompt, enter \h. You’ll then see:
   

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

   List of all MySQL commands: Note that all text commands must be first on line and end with ';' ? (\?) Synonym for `help'. clear (\c) Clear command. connect (\r) Reconnect to the server. Optional arguments are db and host. delimiter (\d) Set statement delimiter. NOTE: Takes the rest of the line as new delimiter. edit (\e) Edit command with $EDITOR. ego (\G) Send command to mysql server, display result vertically. exit (\q) Exit mysql. Same as quit. go (\g) Send command to mysql server. help (\h) Display this help. nopager (\n) Disable pager, print to stdout. notee (\t) Don't write into outfile. pager (\P) Set PAGER [to_pager]. Print the query results via PAGER. print (\p) Print current command. prompt (\R) Change your mysql prompt. quit (\q) Quit mysql. rehash (\#) Rebuild completion hash. source (\.) Execute an SQL script file. Takes a file name as an argument. status (\s) Get status information from the server. system (\!) Execute a system shell command. tee (\T) Set outfile [to_outfile]. Append everything into given outfile. use (\u) Use another database. Takes database name as argument. charset (\C) Switch to another charset. Might be needed for processing binlog with multi-byte charsets. warnings (\W) Show warnings after every statement. nowarning (\w) Don't show warnings after every statement. For server side help, type 'help contents' mysql>

Create a New MySQL User and Database

1. In the example below, testdb is the name of the database, testuser is the user, and password is the user’s password.
   

   create database testdb; create user 'testuser'@'localhost' identified by 'password'; grant all on testdb.* to 'testuser' identified by 'password';

   You can shorten this process by creating the user while assigning database permissions:
   

   create database testdb; grant all on testdb.* to 'testuser' identified by 'password';

2. Then exit MySQL.
   

   exit

Create a Sample Table

1. Log back in as testuser.
   

   mysql -u testuser -p

2. Create a sample table called customers. This creates a table with a customer ID field of the type INT for integer (auto-incremented for new records, used as the primary key), as well as two fields for storing the customer’s name.
   

   use testdb; create table customers (customer_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name TEXT, last_name TEXT);

3. Then exit MySQL.
   

   exit

Reset the MySQL Root Password

If you forget your root MySQL password, it can be flushed and then reset.

1. Stop the current MySQL server instance, then restart it with an option to not ask for a password.
   

   /etc/init.d/mysqld stop mysqld_safe --skip-grant-tables &

2. Reconnect to the MySQL server with the MySQL root account.
   

   mysql -u root

3. Use the following commands to reset root’s password. Replace password with a strong password.
   

   use mysql; update user SET PASSWORD=PASSWORD("password") WHERE USER='root'; flush privileges; exit

4. Then restart MySQL.
   

   service mysqld restart

You’ll now be able to log in again using mysql -u root -p.