Clifford's Blog: April 2012

Last week's post consisted of server-side technologies and today I am going to write about, what is probably the most widespread server-side technology out there and this is knows as PHP.

I will be dividing this post into 3 part like so:

What is PHP?
What is XAMPP?
Creating a simple PHP project using Netbeans 7.1 IDE

PHP Logo

What is PHP?

PHP stands for PHP:Hypertext Preprocessor and it's an open source, server-side scripting language, similar to JSP and Microsoft's ASP.

Basically a PHP file is made out of normal HTML code, but with embedded PHP scripts via the opening <?php and closing ?> tags. PHP scripts are used for various reasons, such as arithmetic calculations, database querying and probably the mostly used, dynamic generation of HTML.

How does it work?

PHP is executed on the hosting server, generates the HTML and sends it to the client as a normal HTML page. This method has an advantage over JavaScript as the client is not able to view your PHP source code as he/she is only receiving the generated HTML, whereas in JavaScript, being a client-side scripting language, has no other option other than sending the source code to the client machine.

XAMPP

What is XAMPP?

XAMPP is an Apache distribution which provides an easy way to install and monitor Apache web server, MySql database, PHP and various other applications typically used on a web hosting server.

Visit http://www.apachefriends.org/en/xampp.html to download a distribution and install it. I have installed mine ages ago, so I will not be using this post as an installation guide. But don't be afraid to do this as it's very simple to install and if any problems arise, there are tons of guides out there to help you out.

Creating a simple PHP project using Netbeans 7.1 IDE

N.B. - To carry out this example your selves, make sure you have already installed XAMPP on your machine.

PHP is known for being easy to use for beginners, so lets test it out a bit shall we.

Mind you this is my first time using PHP, so I'm going to keep it simple and create an HTML page which displays records from a table I have in MySQL.

Step 1

Open Netbeans and click on the New Project button at the top right.

Step 2

Choose PHP from the categories section, select PHP application from the projects section and click on the Next button.

Step 3

Netbeans will automatically scan your machine for the XAMPP document folder and set this as the source location. Give a name to the project and click on the Next button.

Step 4

This step is used for setting the run configuration, make sure the 'run as:' value is Local web site as for this example we will be using the Localhost, which refers to the hosting server on your machine. This could also be referred to as IP address 127.0.0.1

Step 5

This step is used to select a PHP framework but I decided not to select any and clicked on the Finish button.

Congratulations! You have now created your own PHP project...but it really doesn't do anything yet.

So lets continue by creating a simple HTML table which displays the data retrieved from some SQL query. I decided that I want to display the data I have in my sales_order table located in MySQL.

As I've said before, when tackling something new, the best thing to do is divide it into multiple sub-tasks. I divided mine like so:

HTML table
HTML table headers
Connect to MySQL via PHP
Execute an SQL query via PHP
Generate HTML table rows via PHP

Now I am assuming that if you are reading this post, you must have some knowledge of HTML already, therefore you must already know how to create an HTML table with headers, so I will not be going into much detail about that and jump straight to the PHP bits.

<h3 align="center">Sales Order</h3>

<tr>

<th>order_number</th>

<th>customer_number</th>

<th>product_code</th>

<th>order_date</th>

<th>entry_date</th>

<th>order_amount</th>

</tr>

</thead>

<tbody>

</tbody>

</table>

The code above contains the HTML parts I just mentioned. The first line creates a heading for the page and the rest creates a table with hard coded column names in the table header.

Now what I want to do is query my sales_order table and create a table row in the table's body for every record which gets returned. But to do so, first I must establish a connection between the PHP file and the database.

To do so, I used the 'mysql_connect()' function as my database is a MySQL database and embedded this code between the table body element tags.

<h3 align="center">Sales Order</h3>

<tr>

<th>order_number</th>

<th>customer_number</th>

<th>product_code</th>

<th>order_date</th>

<th>entry_date</th>

<th>order_amount</th>

</tr>

</thead>

<tbody>

<?php

// Make a MySQL Connection

mysql_connect("localhost", "root", "MySQLAdmin") or die(mysql_error());

//Set the schema which contains the table/s required

mysql_select_db("source") or die(mysql_error());

</tbody>

</table>

As you can see, I wrapped the PHP code in the <?PHP?> tag and placed it within the table body element tags.

The first line creates a connection to the database via the parameters I passed. These represent the; location of the database, the user name and the password of the MySQL database.

The second line simply specifies the name of the database schema I want to use.

The next step consists of executing a query, looping through the result and creating a row containing the data:

<h3 align="center">Sales Order</h3>

<tr>

<th>order_number</th>

<th>customer_number</th>

<th>product_code</th>

<th>order_date</th>

<th>entry_date</th>

<th>order_amount</th>

</tr>

</thead>

<tbody>

<?php

// Make a MySQL Connection

mysql_connect("localhost", "root", "MySQLAdmin") or die(mysql_error());

//Set the schema which contains the table/s required

mysql_select_db("source") or die(mysql_error());

// Retrieve all the data from the "sales_order" table

$result = mysql_query("SELECT * FROM sales_order") or die(mysql_error());

//loop through all the returned records and create a table row for each

while($row = mysql_fetch_array($result, MYSQLI_ASSOC)){

//Use the echo to output HTML code with the retrieved data

echo "<tr>";

echo "<td align=\"center\">".$row['order_number']."</td>";

echo "<td align=\"center\">".$row['customer_number']."</td>";

echo "<td align=\"center\">".$row['product_code']."</td>";

echo "<td align=\"center\">".$row['order_date']."</td>";

echo "<td align=\"center\">".$row['entry_date']."</td>";

echo "<td align=\"center\">".$row['order_amount']."</td>";

echo "</tr>";

}

</tbody>

</table>

To execute a query I used the 'mysql_query()' function and passed the SQL as a parameter. The second part of that line 'or die(mysql_error())' is an error handler.

After retrieving the table's data I used a while loop with the 'mysql_fetch_array()'. If no more records are available in the query result, this method returns 'False' and therefore stops the iteration. Else returns an array representation of a single row, which I store in '$row'.

Within this loop I used the echo to output the HTML code as strings and concatenated the values in '$row' in order to display the data.

Below is the result of my code:

Possible Improvements
Up to now my PHP script dynamically generates the table rows and populates them with the queried data. This is all well and good, but what if I add a previous page which contains a form? This would enable the user to filter out the returned data, thus creating user interaction!
I might implement this if I have the time and post about how I did it, but for this post, that's it for today :)

Hope you found it interesting and I will be posting some updates I did to the paper toss application I mentioned in earlier posts.

Clifford's Blog

6 April 2012

CMT3313 - Week 7 Post - PHP Technology

1 April 2012

CMT3313 - Week 6 Post - Some Server-Side Technologies