PHP Basic & Variables

Lecturer:
M.Zalmai “Rahmani”
rahmani.zalmai@gmail.com
Web Programming II
Lecture 02
PHP Basic & Variables
Azma Institute
Database Department

PHP Basic
What is PHP?
 PHP stands for PHP: Hypertext Preprocessor
 PHP is a server-side scripting language, like ASP
 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
 PHP is free to download and use

PHP Basic
What is a PHP File?
 PHP files can contain text, HTML tags and scripts
 PHP files are returned to the browser as plain HTML
 PHP files have a file extension of ".php", ".php3", or ".phtml"

PHP Basic
What is 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 Basic
What is 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
 PHP combined with MySQL (you can develop inWindows and serve
on a Unix platform)

PHP Basic
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 FREE to download from the official PHP resource: www.php.net
 PHP is easy to learn and runs efficiently on the server side
Where to Start?
 To get access to a web server with PHP support, you can:
Install Apache (or IIS) on your own server, install PHP, and MySQL
Or find a web hosting plan with PHP and MySQL support

PHP Basic
PHP Syntax
 A PHP scripting block always starts with <?php and ends with ?>. A PHP
scripting block can be placed anywhere in the document.
 On servers with shorthand support enabled you can start a scripting block
with <? and end with ?>

PHP Basic
PHP Syntax
 A PHP file normally contains HTML tags, just like an HTML file, and some
PHP scripting code.
 Below, we have an example of a simple PHP script which sends the text
"Hello World" to the browser:

PHP Basic
PHP Syntax
 A PHP file normally contains HTML tags, just like an HTML file, and some
PHP scripting code.
 Below, we have an example of a simple PHP script which sends the text
"HelloWorld" to the browser:
 Each code line in PHP must end with a semicolon.The semicolon is a
separator and is used to distinguish one set of instructions from another.
 There are two basic statements to output text with PHP:
echo and print. In the example above we have used
the echo statement to output the text "Hello World".
Note:The file must have a .php extension.
If the file has a .html extension,
the PHP code will not be executed.

PHP Basic
PHP Syntax
Comments in PHP
In PHP, we use // to make a single-line comment or /* and */ to make a large
comment block.

PHP Variables
Variables in PHP
 Variables are used for storing values, like text strings, numbers or arrays.
 When a variable is declared, it can be used over and over again in your script.
 All variables in PHP start with a $ sign symbol.
 The correct way of declaring a variable in PHP:
 New PHP programmers often forget the $ sign at the beginning of the
variable. In that case it will not work.
 Let's try creating a variable containing a string, and a variable containing a
number:

PHP Variables
PHP is a LooselyTyped Language
 PHP automatically converts the variable to the correct data type, depending
on its value.
 In a strongly typed programming language, you have to declare (define) the
type and name of the variable before using it.
 In PHP, the variable is declared automatically when you use it.
Naming Rules forVariables
 A variable name must start with a letter or an underscore "_"
 A variable name can only contain alpha-numeric characters and underscores
(a-z, A-Z, 0-9, and _ )
 A variable name should not contain spaces. If a variable name is more than
one word, it should be separated with an underscore ($my_string), or with
capitalization ($myString)

PHP Variables
The Concatenation Operator
 There is only one string operator in PHP.
 The concatenation operator (.) is used to put two string values together.
 To concatenate two string variables together, use the concatenation
operator:

PHP Operators
PHP Operators
This section lists the different operators used in PHP.

Conditional Statement
Conditional Statements
Very often when you write code, you want to perform different actions for
different decisions.
You can use conditional statements in your code to do this.
In PHP we have the following conditional statements:
 if statement - use this statement to execute some code only if a specified
condition is true
 if...else statement - use this statement to execute some code if a condition
is true and another code if the condition is false
 if...else if....else statement - use this statement to select one of several
blocks of code to be executed
 switch statement - use this statement to select one of many blocks of code
to be executed

The if Statement
 Use the if statement to execute some code only if a specified condition is
true.

The if …. else Statement
 Use the if....else statement to execute some code if a condition is true and
another code if a condition is false.
 If more than one line
should be executed if a
Condition is true/false,
the lines should
be enclosed within curly
braces

The if …. Else if….else Statement
 Use the if....else if...else statement to select one of several blocks of code to
be executed.

The PHP Switch Statement is not Recommend in this Course

PHP Basic & Variables

Recommended

More Related Content

What's hot (20)

Viewers also liked (20)

Similar to PHP Basic & Variables (20)

Recently uploaded (20)

PHP Basic & Variables