Francis John Thottungal - PHP Programming: Using MySQL & Oracle

PHP is a programming language to develop dynamic pages for the world wide web. HTML or hypertext markup language is the base for developing web pages but pages created in HTML are static. PHP allows these HTML pages to interact with a database and do things like adding data or retrieving data from one.

In addition, PHP can be used to create the ability to verify user input and provide protection to pages. The prerequisite to understanding PHP is HTML. JavaScript allows dynamism on web pages however, JavaScript is not server based. It works within the client browser. PHP on the other hand is server based. The fact is one needs HTML, JavaScript and scripting language like PHP to complete a professional looking and working page.

This book is about PHP. One may want to consider my book on JavaScript if they need a refresher on that subject.

The webpage for this book is located at: http://beamto.fjtbooks

Before we start:

To run a PHP script which is a server based script one will need the following:

A note pad editor or similar to save files with the extention ".php". and

A location to put the script when complete. This can be a hosted site of which there are many (free or inexpensive web hosting sites) that allow PHP scripts. On a standalone computer it is possible to download a free PHP editor software. The code for this book was developed using the EasyPHP editor (version 17) and server which can be downloaded and installed for free at the time of writing this book. PHP has different versions and the current version is 7. This book is written for both version 5 and 7. There are some significant differences between these two versions. However, many hosting sites are still using version 5 series.

The default database that is included in most hosting sites for PHP is MySQL and the free editors such as the one mentioned above also come with such a database. In addition to this database this book will explore connection to the Oracle database. The Oracle database being used with this book is the stand alone windows version 11.2g Express version which can be downloaded for free at http://www.oracle.com.

Chapter 1. Introduction

The first program by an unwritten tradition in any language is "Hello World". The way to do that in PHP is as follows:

Using notepad with a file extention ".php" create a file called hello (hello.php). Put the following lines in that file.

The location of the script will vary according to the editor. Even in EasyPHP editor it is possible to run this script under the projects folder in the older versions (12 through 14) or in the eds-www folder if in version 17. If an error occurs and it will from time to time-- read the error message, go back to the code written in notepad or editor and correct the code in and around the line number given in the error message. Single quotes mean that the item within them should be taken literally. Double quotes means that the values of the item within the quotes should be taken. For example: $name = 'John' and $name = "John" will give the same result. but $name = "$firstname" and $name ='$firstname' will give two results. Value of firstname= John and $firstname. It is possible to assign to a variable the value of another variable as: $name =$firstname; It is best to use double quotes and that is what will be used throughout the rest of this book. In addition to the print function there is another function called echo() which will print results or messages to the screen. If one is using the EasyPHP editor version (17) which has PHP 7 in it along with PHP 5.6 the interface will look like this. The two options above are for starting the apache server. The settings icon under HTTP server will allow one to switch between PHP 5.6 and PHP 7.1.3 in this case just by selecting the version from the drop down menu and clicking restart. At the time of writing this book most hosting websites - especially the low cost and free ones still have PHP version 5 on their servers. This book will show the output of both versions and highlight where there are significant changes in the new version of PHP. Unless otherwise stated the code seen in this book will work for both old and new versions of PHP. Chapter 2. HTML and PHP Form HTML is required to put PHP to full use. PHP programs can have HTML within it and HTML script can have PHP embedded in it. The first script in this chapter will request the name and phone number of a person. The form will have a box to enter the name and phone number and some radio buttons to choose the title of the person's name. The way it works is like this: An HTML form/page requests the user to input data. It then requests the PHP script on the server to process the data request which ultimately will be added to a database. HTML or a webpage has limited capability to interact with the server when it comes to data processing. It transfers this task using the method. Let us now write the html code first for the html webpage. Mr. Mrs. Ms. Please complete the feedback form Name: Phone: The output of this HTML file is as follows: Please note that the feedback.html file and its associated feedback.php file is kept in the same location. However, this is not a requirement. If the files are in separate folders the path to the PHP file must be included in the statement. So the feedback html file has three parts- selection of title, name and phone. The statement tells that this file will connect to a script file for further processing. The is closed by a Now that this html file is transferring data to a PHP file- the PHP file must be able to capture the data being transferred. Observe the statement. It is missing a method. There are two methods- get and post. What is the difference between the two methods? The GET method sends all the data gathered as a part of the URL. The POST method transmits the data invisibly. Thus choosing GET method might make some vital information visible when the submit button is clicked. There is also a limitation on the amount of data that can be send with GET. The method of transfer from the feedback.html file will be POST. The following change must be made to the feeback.html code in the previous page. The following is the code for the feedback.php file: If the, get method is used in the feedback.html file to transfer data to the feedback.php form then to retrieve the data the $_GET['fieldname'] method should be used. Older versions of PHP such as those before version 4.1 used to use $HTTP_POST_VARS and $HTTP_GET_VARS . Let us now look at another HTML file. This HTML page will request the price, quantity, discount and unfortunately the tax of three different items of a supplier. Let us call these different items as widget1, widget2 and widget3. The HTML code looks as follows: