Building a Database-Driven Web Site Using PHP and MySQL

by Kevin Yank of SitePoint.com

Installing MySQL under Linux

MySQL is freely available for Linux from http://www.mysql.com/ (or one of its mirrors listed at http://www.mysql.com/downloads/mirrors.html). Download the latest stable release (listed as "recommended" on the download page). You should grab the "tarball source download" version, with filename mysql-version.tar.gz.

With the program downloaded, you should make sure you're logged in as root before proceeding with the installation, unless you only want to install MySQL in your own home directory. Begin by unpacking the downloaded file and moving into the directory that is created:

% tar xfz mysql-version.tar.gz
% cd mysql-version

Next you need to configure the MySQL install. Unless you really know what you're doing, all you should have to do is tell it where to install. I recommend /usr/local/mysql:

% ./configure --prefix=/usr/local/mysql

After sitting through the screens and screens of configuration tests, you'll eventually get back to a command prompt. You're ready to compile MySQL:

% make

After even more screens of compilation, you'll again be returned to the command prompt. You're now ready to install your newly compiled program:

% make install

MySQL is now installed, but before it can do anything useful its database files need to be installed too. Still in the directory you installed from, type the following command:

% scripts/mysql_install_db

With that done, you can delete the directory you've been working in, which just contains all the source files and temporary installation files. If you ever need to reinstall, you can just re-extract the mysql-version.tar.gz file.

With MySQL installed and ready to store information, all that's left is to get the server running on your computer. While you can run the server as the root user, or even as yourself (if, for example, you installed the server in your own home directory), the best idea is to set up a special user on the system that can do nothing but run the MySQL server. This will remove any possibility of someone using the MySQL server as a way to break into the rest of your system. To create a special MySQL user, you'll need to log in as root and type the following commands:

% /usr/sbin/groupadd mysqlgrp
% /usr/sbin/useradd -g mysqlgrp mysqlusr

By default, MySQL stores all database information in the var subdirectory of the directory to which it was installed. We want to make it so that nobody can access that directory except our new MySQL user. The following commands will do this (I'm assuming you installed MySQL to the /usr/local/mysql directory):

% cd /usr/local/mysql
% chown -R mysqlusr.mysqlgrp var
% chmod -R go-rwx var

Everything's set for you to try launching the MySQL server for the first time. From the MySQL directory, type the following command:

% bin/safe_mysqld --user=mysqlusr &

The MySQL server has now been launched by the MySQL user and will stay running (just like your Web or FTP server) until your computer is shut down. To test that the server is running properly, type the following command:

% bin/mysqladmin -u root status

A little blurb with some statistics about the MySQL server should be displayed. If you get an error message, something has gone wrong. If retracing your steps to make sure you did everything described above doesn't solve the problem, a post to the SitePoint.com Forums will probably help you pin it down in no time.

If you want to set up your MySQL server to run automatically whenever the system is running (just like your Web server probably does), you'll have to set it up to do so. In the share/mysql subdirectory of the MySQL directory, you'll find a script called mysql.server that can be added to your system startup routines to do this.

Assuming you've set up a special MySQL user to run the MySQL server, you'll need to edit the mysql.server script before you use it. Open it in your favorite text editor and change the mysql_daemon_user setting to refer to the user you created above:

mysql_daemon_user=mysqlusr

Setting up the script to be run by your system at startup is a highly operating system-dependant task. If you're not using RedHat Linux and you're not sure of how to do this, you'd be best to ask someone who knows. In RedHat Linux, the following commands (starting in the MySQL directory) will do the trick:

% cp share/mysql/mysql.server /etc/rc.d/init.d/
% cd /etc/rc.d/init.d
% chmod 500 mysql.server
% cd /etc/rc.d/rc3.d
% ln -s ../init.d/mysql.server S99mysql
% cd /etc/rc.d/rc5.d
% ln -s ../init.d/mysql.server S99mysql

That's it! To test that this works, you can reboot your system and request the status of the server as before to make sure it runs properly at startup.

Article Index Introduction and Contents Part 1: Installation Part 2: Getting Started with MySQL Part 3: Getting Started with PHP Part 4: Publishing MySQL Data on the Web   Challenge Solution Buy this book in print format now

Installing PHP under Linux

SitePoint.com is a fast growing Web Developer Community. Kevin Yank is the Editor of the SitePoint TechTimes, a fresh, technically oriented newsletter for the serious Webmaster.