I can't connect to MySQL database.

When you see this message during installation, type the correct username and password for access to MySQL database. If you are trying to connect to a remote database, check if MySQL is configured for networking (disable option --skip-networking in MySQL configuration file). If you forgot your username and password into MySQL, please, refer to the database documentation (chapter How to Reset the Root Password) or use following steps:

1. Log on to your system as either the Unix root user or as the same user that the mysqld server runs as.
2. Locate the `.pid' file that contains the server's process ID. The exact location and name of this file depends on your distribution, hostname, and configuration. Common locations are `/var/lib/mysql/', `/var/run/mysqld/', and `/usr/local/mysql/data/'. Generally, the filename has the extension of `.pid' and begins with either `mysqld' or your system's hostname. Now you can stop the MySQL server by sending a normal kill (not kill -9) to the mysqld process, using the pathname of the `.pid' file in the following command:

   kill `cat /mysql-data-directory/host_name.pid`

   Note the use of back ticks rather than forward quotes with the cat command; these cause the output of cat to be substituted into the kill command.
   You may also use the following command:

   killall mysqld

3. Restart the MySQL server with the special --skip-grant-tables option:

   mysqld --skip-grant-tables &

4. Set a new password for the root@localhost MySQL account:

   mysqladmin -u root flush-privileges password "newpwd" 

   Replace "newpwd" with the actual root password that you want to use.
5. Restart the MySQL server without any special option.

   mysqld_safe &

6. You should now be able to connect using the new password.