In previous posts I’ve covered a general overview of how SQL and PHP work together and the benefits of creating dynamic content. We have discussed content management systems and how they can simplify your life as a webmaster. Now we’ll start to look at how to actually construct a content management system, starting with connecting PHP to MySQL. 

First, we need to establish a connection using the builtin PHP function, “mysqli_connect”. The old PHP functions for MySQL communication have been outdated by the new “mysqli” family of functions. The standard functions haven’t  been deprecated, so you can still use them, but the added functionality of the “mysqli” group is very useful to have. 

Let’s set up an example where we connect to a MySQL database and pull out the member names, just like in the other examples. For clarity’s sake I’ll use the standard SQL functions instead of regular expressions. 

<?php
 //declare a global variable for database interaction (can be called by any function)
global $mysqli;  
//connect to server and select database; you may need it
$mysqli = mysqli_connect("localhost", "username", "password", “memberDB”);  
//if connection fails, stop script execution
if (mysqli_connect_errno()) {
            printf("Connect failed: %s\n", mysqli_connect_error());
            exit();
}   
//get member information
$get_data_sql = "SELECT lastname, firstname, email FROM members WHERE lastname LIKE “F%”;
  
//get the data or exit if there is an error
$get_data_res = mysqli_query($mysqli, $get_data_sql) or die(mysqli_error($mysqli));
while ($member_info = mysqli_fetch_array($get_data_res)) {
            $lastN = $member_info['lastname'];
            $firstN = $member_info['firstname'];
            $email = $member_info['email'];
echo “Last Name: “.$lastN.”First Name: “.$firstN.”Email: “.$email;
 }
//close connection to MySQL
mysqli_close($mysqli);
?>

When using this code, you will need to fill in “username” and “password” with the actual values you have set up for your database. It is bad practice to use the root account for this, as any script would have administrative access. Instead, set up another account that only has SELECT, INSERT, and UPDATE privileges. 

In the (while) loop we are pulling the data out of an array we construct from the record that MySQL returns based on our query. We then echo or print to screen the information so we can verify the script is working. Notice the break (
) tags inside the echo line – we are embedding HTML tags in PHP scripts. The other parts of the notation enable us to string together strings and variables. When the final print out is made, we will have something like the following:

Last Name: Falwell
First Name: James
Email: jfalwell@gmail.com

Last Name: Farney
First Name: Sarah Marie
Email: sarah_baby@msn.net

….

Last Name: Flaherty
First Name: Timothy
Email: tflaherty@salvationarmy.org

Pretty neat huh? We can use similar code to insert data into the database. The main code that we will reuse is the connection code, so perhaps we should make it modular and stick it into its own function. Next time I’ll show you how to make a login console that you can access from everywhere on your site and connect to different databases or using different logins! We’ll also discuss the php include() directive and how to make your page code modular to save space and leverage the power of the PHP scripting language.

Labels: CMS, command syntax, Content Management, Lesson, MySQL, PHP, SQL

This entry was posted on Wednesday, December 3, 2008 at 10:51 AM.