CSC 506: Software Engineering and Knowledge Engineering Dr. Syed Noman Hasany.
PHP By Dr. Syed Noman Hasany. PHP PHP was originally created by Rasmus Lerdorf in 1995. PHP stands...
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Transcript of PHP By Dr. Syed Noman Hasany. PHP PHP was originally created by Rasmus Lerdorf in 1995. PHP stands...
PHP
ByDr. Syed Noman Hasany
PHP• PHP was originally created by Rasmus Lerdorf in 1995.• PHP stands for PHP: Hypertext Preprocessor (a recursive
acronym).• Hypertext is the underlying concept defining the structure
of the World Wide Web, is the text displayed on a computer or other electronic device with references (hyperlinks) to other text.
• PHP has term “preprocessor” because PHP libraries are already compiled and processed. when any person request any PHP page in browser address bar that request first go to server for example Apache which interprets PHP files and return back response in form of HTML.
PHP
• PHP is a server-side scripting language, like ASP• An embedded scripting language for HTML. • PHP scripts are executed on the server• PHP supports many databases (MySQL,
Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.)
• PHP is an open source software, so it is free to download and use
PHP file
• PHP files can contain text, HTML tags and scripts
• PHP files are returned to the browser as plain HTML
Why PHP?
• PHP runs on different platforms (Windows, Linux, Unix, etc.)
• PHP is compatible with almost all servers used today (Apache, IIS, etc.)
• PHP is easy to learn ( syntax like C) and runs efficiently on the server side
MySQL
• MySQL is a database server• MySQL is ideal for both small and large
applications• MySQL supports standard SQL• MySQL compiles on a number of platforms• MySQL is free to download and use
PHP + MySQL + Apache• PHP combined with MySQL are cross-platform (you can
develop in Windows and serve on a Unix platform)• To get access to a web server with PHP support, you
can: Install Apache on your own server, install PHP, and MySQL
• Wamp server: All in one download and installation for Windows (visual C++ 2010 is needed)– http://sourceforge.net/projects/wampserver/files/latest/download – http
://download.cnet.com/Microsoft-Visual-C-2010-SP1-Redistributable-Package-x86/3000-2247_4-75450985.html
Installing Wamp• If the installation went well, you should have an new icon in
the bottom right, where the clock is:
Localhost• Localhost just refers to the server running on your own
computer. Another way to refer to your server is by using the IP address 127.0.0.1
Running PHP scripts
• Suppose created php script name is first.php√ http://localhost/first.php
• if a folder under www contains the file, then:√ http://localhost/folder_name/script_name.php
• Wrong formats:× c:/wamp/www/test1.php× http://localhost/www/test1.php
Basic PHP Syntax
• A PHP script starts with <?PHP and ends with ?> and can be placed anywhere in the document.
• On servers with shorthand-support, <? and end with ?>, but not recommended due to possible xml conflicts.
<?PHP?>
PHP Comments
• All php files are saved with extension .php• Can be written in notepad or any text editor• Single line comment– // this is single line comment
• Multi line comment– /*….
This is a multi line comment */
A PHP script
<html><body>
<?php echo “hello PHP”; ?></html>
The above program will display hello in the browser
Example 1: title
• <html> <head> <title>Example</title> </head> <body>
<?php echo "Hi, I'm a PHP script!"; ?>
</body></html>
Variables
• Case sensitive• Variables start with a $ symbol• Variables can contain _ or numbers or alphabets• $ should be followed by _ or alphabet and not
by a number• PHP is loosely typed language. There is no strict
data typing• Variable can be assigned with any values
Example 2
<html><body>
<?php echo "hello PHP"; $txt="Hello World!";$x=16;
echo $txt, $x;?></html>
Conditions• If else
if(condn) {….}elseif(condn) {….}else { ….}
• Switch caseswitch(var){case c1: statements;break..Default: statements; break;}
Example 3<html><body>
<?php$d=date("D");if ($d==“Wed") { echo "Have a nice weekend! <br />";
echo “ Good bye”; }else { echo "Have a nice day!"; }?></body></html>
Extract 3 character value from the system date
newline
Loops
• Forfor(intialisation;condition;increment/decrement){ statements }
• While while(condn) { ….}
• Do Whiledo {….} while(condn);
Example 4• <html>
<body>
<?php$i=1;do { $i++; echo "The number is " , $i , "<br />";
echo "The number is " . $i . "<br />"; }while ($i<=5);?>
</body></html>
, or . (dot) as concatenation operator
