PHP
The PHP
Hypertext Preprocessor (PHP) is a programming language that allows web
developers to create dynamic content that interacts with databases.
PHP is
basically used for developing web based software applications.
PHP Introduction
PHP started out as a small
open source project that evolved as more and more people found out how useful
it was. Rasmus Lerdorf unleashed the first version of PHP way back in 1994.
- PHP is a recursive acronym for
"PHP: Hypertext Preprocessor".
- PHP is a server side scripting
language that is embedded in HTML. It is used to manage dynamic content,
databases, session tracking, even build entire e-commerce sites.
- It is integrated with a number of
popular databases, including MySQL, PostgreSQL, Oracle, Sybase, Informix,
and Microsoft SQL Server.
- PHP is pleasingly zippy in its
execution, especially when compiled as an Apache module on the Unix side.
The MySQL server, once started, executes even very complex queries with
huge result sets in record-setting time.
- PHP supports a large number of
major protocols such as POP3, IMAP, and LDAP. PHP4 added support for Java
and distributed object architectures (COM and CORBA), making n-tier
development a possibility for the first time.
- PHP is forgiving: PHP language
tries to be as forgiving as possible.
- PHP Syntax is C-Like.
Common uses of PHP:
- PHP performs system functions,
i.e. from files on a system it can create, open, read, write, and close
them.
- PHP can handle forms, i.e. gather
data from files, save data to a file, thru email you can send data, return
data to the user.
- You add, delete, modify elements
within your database thru PHP.
- Access cookies variables and set
cookies.
- Using PHP, you can restrict users
to access some pages of your website.
- It can encrypt data.
Characteristics of PHP
Five important
characteristics make PHP's practical nature possible:
- Simplicity
- Efficiency
- Security
- Flexibility
- Familiarity
Example:
To get a feel for PHP,
first start with simple PHP scripts. Since "Hello, World!" is an
essential example, first we will create a friendly little "Hello,
World!" script.
As mentioned earlier, PHP
is embedded in HTML. That means that in amongst your normal HTML (or XHTML if
you're cutting-edge) you'll have PHP statements like this:
|
<html>
<head>
<title>Hello World</title>
<body>
<?php echo "Hello, World!";?>
</body>
</html>
|
It will produce following
result:
|
Hello, World!
|
If you examine the HTML
output of the above example, you'll notice that the PHP code is not present in
the file sent from the server to your Web browser. All of the PHP present in
the Web page is processed and stripped from the page; the only thing returned
to the client from the Web server is pure HTML output.
All PHP code must be
included inside one of the three special markup tags ate are recognised by the
PHP Parser.
|
<?php PHP code goes here ?>
<?
PHP code goes here ?>
<script language="php"> PHP
code goes here </script>
|
Most common tag is the
<?php...?> and we will also use same tag in our tutorial.
From the next chapter we
will start with PHP Environment Setup on your machine and then we will dig out
almost all concepts related to PHP to make you comfortable with the PHP
language.
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