php_mysql_tutorial_1.pdf

PHP/MySQL Tutorial

by Graeme Merrall

Lesson 1:

Overview

Open source has brought a lot more than Linux to the computing world. It has also given us PHP and

MySQL. According to Graeme, PHP and MySQL are the world's best combination for creating data-driven

sites. In the first installment of this three-lesson tutorial, our Kiwi guide covers everything you need to

know to begin developing database hubs. He gives instructions for installation on both Unix and Windows,

and then goes on to show some simple scripts that will insert information into a database and display that

data on a Web page.

Lesson 2 covers more PHP/MySQL goodies than you could probably imagine. Graeme starts by showing

while loops, then talks about the ever-useful if -else statement. But this information alone means little if

you don't continue and see how PHP can be used with HTML forms. By the time you've polished off this

lesson, you'll be able to add, edit, and remove information from your database.

In Lesson 3, Graeme shows some of the secrets that will turn your simple data-driven site into a useful

application. As he covers validation, he'll show how to prevent users from leaving key form fields blank and

how to make sure numeric files don't contain letters. He'll also teach you how PHP handles includes and

functions. Plus you'll see how these two features, when deployed together, can make the coder's life much

easier. Graeme winds it all up with some tearful parting words and a bit of advice for the aspiring

PHP/MySQL coder.

Other PHP articles on Webmonkey:

Site Navigation with PHP

Image Creation with PHP

Threaded Discussion with PHP/MySQL

Introducing PHP and MySQL

Unless you've been living on Mars for the last six to eight months, you've heard of open source software

(OSS). This movement has got so much momentum that even the big boys are taking notice. Companies

like Oracle, Informix, and a host of others are releasing their flagship database products for that poster

child of the OSS movement, Linux.

Having a massively complex RDBMS (relational database management system) is all well and good if you

know what to do with it. But perhaps you are just getting into the world of databases. You've read Jay's

article and you want to put up your own data-driven Web site. But you find you don't have the resources

or desire for an ASP server or some pricey database. You want something free, and you want it to work

with Unix.

Enter PHP and MySQL. These two make up what must be the best combination for data-driven Web sites

on the planet. You needn't take my word for it. An unofficial Netcraft survey shows that PHP usage has

jumped from 7,500 hosts in June 1998 to 410,000 in March 1999. That's not bad. The combination was also

awarded Database of the Year at Webcon98, where it received a lovely tiara.

MySQL is a small, compact database server ideal for small - and not so small - applications. In addition to

supporting standard SQL (ANSI), it compiles on a number of platforms and has multithreading abilities on

Unix servers, which make for great performance. For non-Unix people, MySQL can be run as a service on

Windows NT and as a normal process in Windows 95/98 machines.

PHP is a server-side scripting language. If you've seen ASP, you'll be familiar with embedding code within an

HTML page. Like ASP, PHP script is processed by the Web server. After the server plays with the PHP code,

it returns plain old HTML back to the browser. This kind of interaction allows for some pretty complex

operations.

In addition to being free (MySQL does have some licensing restrictions though), the PHP-MySQL

combination is also cross-platform, which means you can develop in Windows and serve on a Unix platform.

Also, PHP can be run as an external CGI process, a stand-alone script interpreter, or an embedded Apache

module.

If you're interested, PHP also supports a massive number of databases, including Informix, Oracle, Sybase,

Solid, and PostgreSQL - as well as the ubiquitous ODBC.

PHP supports a host of other features right at the technological edge of Internet development. These

include authentication, XML, dynamic image creation, WDDX, shared memory support, and dynamic PDF

document creation to name but a few. If that's not enough, PHP is easy to extend, so you can roll your

own solution if you're programming savvy.

Finally, since both efforts are collaborative in nature, there's always plenty of support from documentation

and mailing lists. Bugs are fixed rapidly, and requests for features are always heard, evaluated, and if

feasible, implemented.

Enough talk! Let's go over what we're going to cover in this tutorial.

Lesson 1 is going to cover the installation of these products on both Unix and Windows systems. If you

don't need to worry about that (you're working on your ISP's machine, perhaps), jump right to the first

example scripts, where the magic starts.

In Lesson 2 we'll look at some more complex scripting goodies, including looping, form input, and sending

data from and to the database.

Lesson 3 will cover validation and techniques for making your PHP scripts smart and clean.

Let's roll.

Installing MySQL

Let's jump straight in, grab ourselves a copy of these great packages, and get hacking! This isn't simple

stuff. There are lots of options available to you for obtaining, compiling, and installing the software. Let's

deal with MySQL first, as we'll need it before we get PHP going.

MySQL central is http://www.mysql.com/. As befits a program of its stature, there are a zillion mirrors

located all over the globe, so do the Internet a favor and pick the one closest to you.

You've got plenty of choices at this point. If you're a do-it-yourselfer, then grab the source code. If you're

not that brave, there are some precompiled binaries for other platforms already available for download.

In addition, there is a shareware version of MySQL for Windows users. It is an older version of MySQL. If

you want the latest version, you'll have to purchase a license. There are also ODBC drivers that let your

applications talk to MySQL. Various other exciting bits and pieces are lurking about on the site, too, so

take a look.

The precompiled Unix versions and the Windows version are as simple as unpacking and going, and they

don't require much explanation. So let's compile from the source code. Windows users, please keep in mind

that you need to run mysqld in the mysql/bin directory.

Download the compressed file into your source directory and uncompress and untar it using gzip and tar.

The fast way of doing this is to type:

gunzip < mysql-xxxx.tar.gz | tar xvf -

The xxxx is where you put the version number. This will create a directory called mysql-xxxx, which

contains all the source files. Move to that directory by typing cd mysql-xxxx and check out the various

README and INSTALL files. They're lifesavers in sticky situations.

MySQL comes with a handy configuration script. Simply type ./configure and let things take care of

themselves. If you need to specify what happens and where, typing ./configure --help gives you a list of

options to choose from. For example, if you're compiling on a machine with little memory, you can opt for

the --with-low-memory flag. I like MySQL to install in one handy directory tree rather then in various

locations on my machine, so I specify an install location with the --prefix flag.

You can also specify lots of other options, such as what to compile and what to skip. Let's assume that we

want everything under /usr/local/mysql on our server. This means we'd type ./configure --

prefix=/usr/local/mysql.

The configure script will run and inspect your system and then build the necessary files to successfully

compile. If it fails, you'll usually get a helpful error message saying why. Quite often, you'll find the script

will fail when it's looking for threading libraries. Check that you've got MIT-pthreads installed on your

machine, and if not, add them. Linux users will have to download LinuxThreads. These are critical libraries

that allow MySQL to multithread (i.e., run multiple versions of itself). Recent distributions of Linux may

already have these libraries installed.

If everything goes according to plan, simply type make and go get a coffee. MySQL is a complex program

and takes some time to compile. If you get an error, check the documentation to see if there is anything

specific that you've missed for your particular OS.

Next, type make install and all the necessary files will be installed in all the necessary spots. Now you're

almost ready to roll! If you are a MySQL virgin and you've never installed MySQL before, you need to

create the default permissions, so type ... scripts/mysql_install_db to set these up.

That's it. We're ready to roll. All we need to do is add the ability to start and stop the server at boot -up

and shutdown times. And yes, there's a script for that as well. Typing mysql.server start starts the server,

and mysql.server stop stops the server. It's kind of obvious, really. To start the server manually (so you

can play without rebooting) enter the root directory in your MySQL installation (/usr/local/mysql) and type

bin/safe_mysqld &. You're halfway there. Now on to PHP.

Installing PHP

Phew! Hopefully you've got MySQL all up and running by now. That was almost fun! Now for PHP ... This

process is slightly easier, but the array of options is dazzling. Don't be daunted, though. You can always go

back later and recompile PHP to add or remove options as needed.

The home of PHP is http://www.php.net/. The PHP site is a mine of information, from project listings to bug

reports. As with MySQL, you should choose a nearby mirror. Obviously you'll want the Downloads section to

get PHP.

Your range of options here is a little more limited. A few precompiled binaries are available, but these are

experimental. If you're on anything except a Windows platform, grab the source code and compile it

yourself.

But first let's cover Windows. When using PHP, a common practice is to develop on a Windows machine and

then run your site on a Unix server. It may end up that you will do this yourself, which means you need to

be proficient in installing on both platforms.

Let's grab the Windows binary and uncompress it using our favorite Zip decompression tool into a directory

on your C drive called php3. The supplied README file deals with the installation in some detail, but here's

the Reader's Digest version: If you want to install PHP to a folder other than C:\php3, you'll need to edit

the .inf file that comes with PHP.

In the php3 directory, you'll find a lot of .dll files. Take all the .dll files that don't begin with php_ and move

them into your \windows\system directory. Then rename php.ini-dist to php3.ini and move it into your

\windows directory. If you open up that file, you'll see there are lots of interesting things to change. For

now just "uncomment" the line:

extension=php3_mysql.dll

If you're using Apache for Win32, set up Apache to recognize and parse PHP files. Depending on the version

of Apache you're using, you'll need to add the following to either the httpd.conf or srm.conf file:

ScriptAlias /php3/"c:/path-to-php-dir/"

AddType application/x-httpd-php3 .php3

Action application/x-httpd-php3"/php3/php.exe"

Or if you're using IIS or PWS, right-click on php_iis_reg.inf and select 'Install'. You'll need to reboot for IIS

to see this change.

OK, now that Windows is out of the way, let's get to Unix. Of course, we'll be compiling from source code.

As with MySQL, download and unpack the source code. Again, PHP comes with a configure script. You

can't get away with going for defaults here, though. Run ./configure -help | more to see pages and pages

of new and interesting options. You have to decide between compiling as a CGI or as an Apache module. If

you are using the Apache Web server and you are able to recompile it, use the module: It's faster and

easier to use. Otherwise, you can go with the CGI version. We also need to compile in MySQL support.

For now we'll assume that we're running the module with MySQL support. If you want to add other options

or other libraries, you can do this later. Type:

./configure --with-apache=/path/to/apache/dir --with-mysql=/usr/local/mysql

Skip the -with-apache option if you're creating a CGI version. The configure process will run and produce

the relevant system files. Now simply type make again.

It's time for another coffee. If you start feeling a bit nervous and shaky at this point, don't worry about it.

We all get a little anxious during our first PHP install. Have some more coffee.

If you've created a CGI version, you're now ready to roll. Simply copy the resulting executable file into your

CGI file. For Apache module users, type make install to copy files to your Apache directory. From there,

follow the instructions to add a module to Apache and recompile.

You'll need to tell your Web server how to process pages through the PHP program now. If you're not using

Apache, you'll need to check your Web server documentation on how to get it to process documents with

a .php3 extension. Apache 1.3.x users can simply add AddType application/x-httpd-php3 .php3 to the

httpd.conf or srm.conf file. If you're using the CGI version, you'll need to add the following before AddType:

ScriptAlias /php3/"/path-to-php-dir/" AddType application/x-httpd-php3 .php3 Action application/x-httpd-

php3"/php3/php"

That's it. With any luck, you've now got MySQL running and PHP functioning. Don't forget to check the

FAQs and documentation if you get stuck. Also try the mailing lists.

Now that we've managed all that, lets put this stuff in motion!

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