This is Part 1 of my PHP Login System tutorial. By the end of this series, you’ll have your own custom social networking site. Users will be able to register, login, edit their profile and add pictures. We’re aiming for a very stripped down version of Facebook and Myspace.

For this tutorial you’ll need a webserver running PHP and mySQL. Click here for instructions on how to set one up on your local machine with XAMPP.

Lets start by making our database. Our users table will have 7 fields.
id, first, last, username, password, email and about.

Heres the SQL code to make this happen. You can paste it into your phpmyadmin SQL tab. Make sure you change the `db` in the first line to match the name of your database.

CREATE TABLE `db`.`users` (
`id` INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY ,
`first` VARCHAR( 32 ) NOT NULL ,
`last` VARCHAR( 32 ) NOT NULL ,
`username` VARCHAR(32) NOT NULL,
`password` VARCHAR(255) NOT NULL,
`email` VARCHAR(255) NOT NULL,
`about` TEXT NOT NULL
) ENGINE = MYISAM;

We make the id auto_increment so that every user that is added to the db has their own id. Since this field will be unique, we’ll make it our primary key. It will be used to reference each user later.

Our database is setup. We just need to connect to it using php. We’ll create our first php file, “db_connect.php”.

PHP has built in functions to interact with mysql databases, mysql_connect and mysql_select_db.

The mysql_connect function takes 3 arguments, the host, username, and password. We’ll store the result of this function into a variable. If the connect fails you tell it to die and show the error output on the screen using mysql_error().

If your connection is successful, you just have to select the database you want to
interact with. The mysql_select_db(“name_of_your_db”,”the_connection_resource”) function will select your database from the successful connection we established previously.

Heres the php code

<?php
$con = mysql_connect(localhost,"username","password") or die(mysql_error());
$db = mysql_select_db("db",$con);
?>

We’ve connected to the mysql server and selected our db.
Im going to add a function into this page that we’ll be using later

function protect($string)
{
  $string = mysql_real_escape_string($string);
  return $string;
}

This function will clean what the users submit to the database so that we won’t need to worry about SQL Injection. I made it a function because typing “mysql_real_escape_string” every time you need to use it is a pain.

The entire db_connect.php code

<?php
//db_connect.php
$con = mysql_connect(localhost,"username","password") or die(mysql_error());
$db = mysql_select_db("db",$con);
 
function protect($string)
{
 $string = mysql_real_escape_string($string);
 return $string;
}
?>

Next will be Part 2 where we create the Login and Registration Page.